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Hemostatic markers and platelet aggregation factors as predictive markers for type of stroke and neurological disability following cerebral infarction
Abstract
We investigated the plasma levels of D-dimer, fibrinogen, beta-thromboglobulin (BTG) and platelet factor-4 (PF-4), indices of the occurrence of platelet activation in vivo, to find out their role in pathophysiology of ischemic stroke and whether or not such a role has any effect on the disability and the prognosis of stroke patients. A total of 76 patients with AIS aged from 26 to 85 (32 men, 44 women) and 30 cases as controls with similar age (18 men, 12 women) were included in the study. The plasma levels of D-dimer, BTG and PF-4 were measured by ELISA method using a special commercial kit. The cases were allocated into two groups as non-embolic (NEI) and cardioembolic stroke (CEI). The D-dimer levels in 76% of 42 patients in NEI group (p<0.05) and 85.2% of 34 patients in CEI group (p<0.05) were outside the confidence interval (CI) defined for the control group. The levels of BTG were elevated in 81% of 42 cases with NEI (p<0.05) and in 76% of 34 cases with CEI, with reference to CI of control group. The levels of PF-4 were significantly increased in 86% of cases with NEI (p<0.05) and in 88% of cases with CEI than controls (p<0.05). It was observed that the cases with high Rankin scores had higher levels of D-dimer (p<0.005), BTG (p<0.01) and PF-4 (p<0.01) than those with lower scores. There was a correlation between hemostatic markers, platelet activation and functional disability. D-dimer levels were an important marker that determined to degree of the activation of hemostatic system, especially in CEI subtype. The platelet aggregation had an important role in pathophysiology of ischemic stroke and this condition is significant in NEI subgroup and subjects with large infarcts and high disability scores.
... A total of 7 different biomarkers of primary hemostasis were measured in 10 studies, encompassing a total of 1314 patients of whom 690 (52.5%) were male and with a mean age ranging from 64.7 to 74.4 years. [7][8][9][10][11][12][13][14][15][16] Platelet count was measured in 281 patients <8 hours after symptom onset and showed no significant association with poor outcome. 10 In the same study, mean platelet volume was significantly higher in patients with poor outcome compared to patients with a good prognosis. ...
... 11 β-Thromboglobulin and platelet factor-4 levels measured <48 hours after symptom onset were shown to increase with ascending mRS score in one study conducted in 76 patients. 9 A total of 7 studies, including 881 patients, reported on VWF:Ag (Von Willebrand Factor antigen) levels and outcome after stroke. 7,8,[12][13][14][15][16] Most studies used ELISA for measuring VWF:Ag levels in plasma. ...
... A total of 6 biomarkers of fibrinolysis were measured in 21 different studies with a total of 3988 patie nts. 9,11,[15][16][17]20,21,24,26,27,29,33,[37][38][39][40][41][42][43][44][45] Seventeen studies including 3696 patients reported on D-dimer and clinical outcome after ischemic stroke. 9,15-17,21,24,26,27,29,33,37-43 Eight studies determined D-dimer levels with (latex enhanced) immunoturbidimetric assays. ...
Objectives—
The prediction of patients at risk for poor clinical outcome after acute ischemic stroke remains challenging. An imbalance of coagulation factors may play an important role in progression and prognosis of these patients. In this systematic review, we assessed the current literature on hemostasis biomarkers and the association with poor clinical outcome in acute ischemic stroke.
Approach and Results—
A systematic search of Embase, Medline, Cochrane Library, Web of Science, and Google Scholar was performed on studies reporting on hemostasis biomarkers and clinical outcome after acute ischemic stroke. Studies were considered eligible if blood samples were collected within 72 hours after symptom onset. Additionally, clinical outcome should be assessed using a disability score (Barthel Index or modified Rankin scale). Methodological quality of included studies was assessed with an adapted version of the Quality Assessment of Diagnostic Accuracy Studies questionnaire. A total of 80 articles were read full text, and 41 studies were considered eligible for inclusion, reporting on 37 different hemostasis biomarkers. No single biomarker appeared to be effective in predicting poor clinical outcome in acute ischemic stroke patients.
Conclusions—
Based on current literature, no clear recommendations can be provided on which hemostasis biomarkers are a predictor of clinical outcome after acute ischemic stroke. However, some biomarkers show promising results and need to be further investigated and validated in large populations with clear defined study designs.
... Platelets in particular play an important part in the formation of cerebral atherothrombotic events and ischemic processes, which encompass adhesion, release reaction, and aggregation of platelets. 4,5 Circulating platelets are heterogeneous with regard to their size, density, and reactivity, and platelet volume indices are biomarkers of degree of platelet activation that are thought to be associated with systemic inflammatory responses. These indices include platelet count )PC(, mean platelet volume )MPV(, and platelet distribution width )PDW(. ...
... It has been postulated that the MPV that is determined early post-stroke )for example, within the first 48 hours( largely represents the pre-stroke status. [4][5][6][7][8][9][10] International literature has controversial reports regarding the effect of MPV on stroke events. Although it has generally been asserted that platelet volumes are elevated in stroke, no previous study has examined the association between MPV and first-ever acute ischemic stroke )FEAIS( with regard to prognosis and stroke severity. ...
... Several plausible explanations may account for these contradictions between studies; first, these studies probably failed to reveal time-dependent artificial elevations in MPV due to the platelet-swelling that is observed following both EDTA and citrate anticoagulant incubation, and which is more prominent with regard to EDTA anticoagulants. 5,12,29,30 Some recent studies have found that this elevation of platelet volume amounts to less than 0.5 fL when the waiting interval is less than 2 hours after venipuncture. 8,16,[29][30][31] Second, the samples were measured with different automated cell counters, which may vary in their methods, hence, the accuracy of MPV measurements may be influenced by the platelet-counting method of the analyzers and can show poor agreement. ...
Objective
To investigate any possible effects of mean platelet volume (MPV) on short-term stroke prognosis and functional outcome in patients with first-ever acute ischemic stroke (FEAIS).
Methods
This retrospective cross-sectional study included 798 FEAIS patients admitted to the emergency department of a tertiary care hospital in Adiyaman, Turkey between January 2013 and June 2015. The data were evaluated according to whether alive or dead, MPV levels, modified Rankin scale (MRS) scores, National Institutes of Health Stroke Scale (NIHSS) scores. The patients were divided into 3 groups based on MPV level as 4.4-7.4 fL, 7.5-10.4 fL, higher than 10.4 fL.
Results
A total of 250 patients with FEAIS were included in the study. In both those who survived and those who died, the area under the curve related to hospitalization days, time interval of venipuncture (TIV), and MPV measurements was not statistically significant (p>0.05). The 3 MPV groups showed no significant differences in terms of MRS score, median NIHSS score, hospitalization, and TIV. In subgroups based on MRS scores, there were no statistically significant differences according to median latency (p=0.087), median hospitalization (p=0.394), TIV (p=0.201), and MPV levels (p=0.847). Furthermore, there were no differences in MPV levels between the MRS based groups (p=0.527).
Conclusion
The results showed that MPV was not a significantly associated and reliable marker for the prediction of prognosis or functional outcome of FEAIS attack.
... In the present study, advanced age (≥75 years), a female gender, and an elevated D-dimer level were independent predictors of a poor outcome (mRS score ≥3). These findings are consistent with those of several previous studies.2,14-16 Importantly, combining all three predictors yielded a high negative predictive value (0.889). ...
... Many clinical characteristics are known to be predictors of a poor outcome among patients suffering acute CI,2-4 including age, gender, severity of CI, cardiovascular comorbidities, diabetes mellitus, and prestroke functional status. Some blood markers are also associated with a poor outcome among patients with CI.18,26 Higher levels of C-reactive protein,15,18,19 D-dimer, 14-16 plasminogen activator inhibitor-1,20 and fibrinogen19 have been reported to predict a poor outcome; however, the previous results have not always been consistent.17 In the present study, advanced age (≥75 years), a female gender, and an elevated D-dimer level were independent predictors of a poor outcome (mRS score ≥3). ...
... We previously reported that an elevated D-dimer level was useful for distinguishing cardioembolic infarction from other CI subtypes in the emergency room.13 Some investigators have reported that the D-dimer level is an independent predictor of poor outcome among patients with acute CI.14-16 However, conflicting results have also been reported.17-20 ...
Plasma D-dimer levels are elevated during the acute phase of cerebral infarction (CI). We investigated whether the D-dimer level on admission and other clinical characteristics could be used to predict the poor outcome of patients with acute CI.
The clinical characteristics and plasma D-dimer levels measured within 3 days of onset were compared according to outcome among patients with acute CI.
In total, 359 consecutive patients (mean age, 71.8 years) were examined, of which 174 had a poor outcome [score on the modified Rankin scale (mRS) ≥3] at 30 days after hospitalization. The mean mRS score was higher and a poor outcome was observed more frequently among women than among men (p<0.001 for each). The proportions of women, cardioembolism, atrial fibrillation, advanced age (≥75 years), prior history of CI or transient ischemic attack, and elevated D-dimer level (≥1.0 µg/mL) were significantly higher among patients with a poor outcome than among those with a good outcome. A multivariate analysis showed that elevated D-dimer level [≥1.0 µg/mL; odds ratio (OR), 2.45; 95% confidence interval (95% CI), 1.52-3.89; p<0.01], advanced age (OR, 1.93; 95% CI, 1.21-3.07; p<0.01), and female gender (OR, 1.75; 95% CI, 1.08-2.83; p=0.02) were independent predictors of a poor outcome.
Certain clinical characteristics (gender and advanced age) and an elevated D-dimer level upon admission can be used to predict the outcome of patients with acute CI at 30 days after hospitalization.
... Several studies have also shown that D-dimer is associated with a higher risk of stroke, mainly with acute ischemic stroke [14,15]. It has been shown that D-dimer plays a crucial role in stroke diagnosis, progression, and death [16][17][18]. The results of some prior studies demonstrated a positive correlation between elevated D-dimer levels and the occurrence of ischemic stroke [19][20][21]. ...
... D-dimer has also a role in determining the best anticoagulation duration for patients with VTE, for DIC diagnosing and monitoring, and as a tool for identifying individuals with high risk for VTE [49]. Some prior studies have also shown the use of D-dimer in stroke diagnosis, progression, and death [17,18,50,51]. We indicated that, with 77.6% of performance, D-dimer could identify ischemic stroke among hypertension patients. ...
Background: Ischemic stroke is a common type of stroke that leads to death and functional
disability in hypertensive patients. However, there are no well-studied non-invasive and less
expensive fluid biomarkers routinely used to detect ischemic stroke in hypertensive patients.
Hence, this study aimed to tease out the performance of D-dimer, fibrinogen, and the D-dimer to
fibrinogen ratio (DDFR) in predicting hypertension-associated acute ischemic stroke.
Methods: A hospital-based cross-sectional study was done from October 2022 to January 2022 at
Yikatit 12 Hospital Medical College, Ethiopia. We recruited 55 hypertensive patients who had an
ischemic stroke and 110 who did not. A ROC curve was used to calculate the areas under the
curves (AUCs) and determine the diagnostic power of the D-dimer, fibrinogen, and DDFR. The
Youden index was used to find the best cut-off points for biomarkers in detecting acute ischemic
stroke. A De Long test was employed to show whether there was a significant difference between
the AUCs of biomarkers in diagnosing ischemic stroke.
Results: D-dimer yielded the highest diagnostic power (AUC = 0.776) in detecting acute ischemic
stroke, followed by DDFR (AUC = 0.763) and fibrinogen (AUC = 0.694), but there was no significant difference between them. At 0.52 μg/ml cut-off point, D-dimer had 82.9% sensitivity,
66.7% specificity, 62.5% PPV, and 85.3% NPV to diagnose acute ischemic stroke. Fibrinogen
could detect acute ischemic stroke at 405.85 mg/dl level, with 70.0% sensitivity, 57.1% specificity, 41.2% PPV and 81.6% NPV. At a 1.83 ratio, DDFR might also identify ischemic stroke with
80.0% sensitivity, 67.1% specificity, 51.1% PPV, and 88.7% NPV.
Conclusion: We showed D-dimer, fibrinogen, and DDFR as promising, affordable, and non-invasive
biomarkers for the detection of ischemic stroke among subjects with hypertension. This will help
clinicians make an early diagnosis and better guide patient therapy.
... Many researchers have concluded that higher D-dimer levels are associated with a higher risk of stroke [28][29][30]. It has been shown that D-DI is associated with the neural damage biomarker in severe stroke, and it can predict stroke progression and death in acute stroke [31][32][33][34]. Nevertheless, a number of investigators did not reach conclusions on the relationship between D-DI and stroke [35,36]. ...
... This is congruent with another study that showed D-DI levels to be appreciably elevated in stroke patients compared to controls [68]. In addition, a plethora of other studies also reported similar findings, in which a significantly increased D-DI levels were noted in stroke patients compared to the apparently healthy controls [33,69,70]. Likewise, other researchers suggested that elevated levels of D-DI increase the risk of both ischemic and hemorrhagic stroke [25]. ...
Background:
Stroke is one of the leading causes of global mortality and disability, particularly in hypertensive patients. This study aimed to compare lipid profile, fibrinogen, and D-dimer levels between hypertensive patient with and without stroke.
Methods:
This was a facility-based cross-sectional study conducted from November 2022 to January 2023 among 115 hypertensive patients (70 patients without stroke and 45 with stroke) who had follow-up at Yikatit 12 Hospital Medical College, Ethiopia. All data analyses were done using SPSS version 25.0 and comparisons of variables between groups were made using the Chi-square test, independent sample t-test, and Mann-Whitney U test. Multiple logistic regression analysis was done to identify predictors of stroke among hypertensive patients. A p-value <0.05 was assumed to be statistically significant for all statistical tests.
Results:
Significantly elevated levels of TC, LDL-C, D-DI, and fibrinogen were observed in the stroke group than in the non-stroke group (p-value<0.05). The mean values of TC, D-DI, and fibrinogen were significantly higher in patients with ischemic stroke compared to those with hemorrhagic stroke. Duration of hypertension (AOR: 1.21; CI: 1.10, 2.09), TC (AOR:1.07; CI: 1.01, 1.22), D-DI (AOR: 1.15; CI: 1.05, 1.69) and fibrinogen (AOR:1.19; CI: 1.10, 2.89) were identified to be independent predictors of stroke in hypertensive patients.
Conclusion:
The circulating levels of TC, LDL-C, D-DI and fibrinogen in hypertensive patients with stroke were significantly higher than in those without stroke. But only TC, D-DI, and fibrinogen were found to be predictors of stroke in hypertensives. Considerably higher TC, D-DI, and fibrinogen levels were also seen in patients with ischemic stroke than in those with hemorrhagic stroke. This confirms the key roles of dyslipidemia (hypercholesterolemia) and aberrant hemostatic activation to stroke development, notably ischemic stroke.
... The interruption of oxygen and glucose supply, essential for the production of high-energy phosphate compounds, and the existence of mediators of ischemic cellular injury are the secondary mechanisms leading to stroke [4,5]. Stroke is also associated with residual physical, cognitive, and behavioral impairments, recurrence, and increased risk of other types of vascular events [6]. ...
... These events are of prime importance in the progression and prognosis of stroke. Platelets play the leading role in the formation of cerebral atherothrombotic -ischemic processes, adhesion and aggregation [6,7]. Platelet size is found to be elevated in individuals with vascular diseases such as hypertension and diabetes mellitus [8]. ...
Objectives: The objectives of this study were to study the correlation and significance of platelet count (PC) and mean platelet volume (MPV) on the clinical severity of stroke and the interrelation of MPV and PC in acute ischemic stroke (AIS) patients. Methods: We studied MPV and PC of 52 AIS patients consecutively admitted in Neurology department at Geetanjali Medical University, India. Platelet variables were measured and compared with control of similar age, sex, and without vascular events. Conclusion: Increased MPV has an independent association with AIS and its severity and the mean MPV range did not change after acute treatment. It may be possible that these changes precede the vascular event, and further studies are warranted to unravel the underlying mechanism.
... The interruption of oxygen and glucose supply, essential for the production of high-energy phosphate compounds, and the existence of mediators of ischemic cellular injury are the secondary mechanisms leading to stroke [4,5]. Stroke is also associated with residual physical, cognitive, and behavioral impairments, recurrence, and increased risk of other types of vascular events [6]. ...
... These events are of prime importance in the progression and prognosis of stroke. Platelets play the leading role in the formation of cerebral atherothrombotic -ischemic processes, adhesion and aggregation [6,7]. Platelet size is found to be elevated in individuals with vascular diseases such as hypertension and diabetes mellitus [8]. ...
Objective: Role of platelets in the pathogenesis of the atherothrombosis and ischemic stroke has been documented. Mean platelet volume (MPV) and platelet count (PC) could be important predictors of acute ischemic stroke (AIS), its severity; therefore we investigated the correlation of MPV & PC in AIS patients. Methods: We studied MPV and PC of 52 AIS patients consecutively admitted in Neurology department at Geetanjali Medical University, India. Platelet variables were measured and compared with control of similar age, sex and without vascular events. Results: Out of 52 patients, 30 (57.69%) had Thirty (57.69%) patients had significantly higher MPV in AIS group (12.45fL compared with normal range of 6–11 fL in control,p<0.001). No significant differences were found between male and females, but the total mean was elevated. The mean of PC was 1.76×105 cells/cumm (normal range) and there was no correlation between the change in PC and AIS in both sexes. Repeated measurements of MPV and PC were also recorded on follow-up which showed no significant changes from the acute phase; however, MPV remained elevated. The comparison of MPV in patients with mRS score 2 versus 4, 2 versus 5, 3 versus 4 and 5, and 4 versus 5 were found to be statistically significant (p<0.05). Conclusion: Increased MPV has an independent association with AIS and its severity and it could not change after acute treatment. It is possible that these changes precede the vascular event, and further studies are warranted to unravel the underlying mechanism.
... In humans, a reliable and inexpensive diagnostic test and predictor of prognosis and risk of recurrence is being sought for ischemic stroke (4). It has been shown that plasma D-dimer levels are elevated in acute ischemic stroke compared to healthy control populations (4)(5)(6)(7)(8)(9)(10)(11). As D-dimers are solely derived from the degradation of cross-linked fibrin monomers in stable clots, they are specific for active coagulation and fibrinolysis. ...
... In humans, a normal D-dimer has been shown to be a valuable negative predictor to rule out intravascular thrombotic processes, in particular in cases of venous thromboembolic disease such as central venous thrombosis and deep venous thrombosis (4,12,24,25). Ddimer has also been shown to be significantly elevated in human ischemic stroke compared to healthy control populations (5)(6)(7)(8)(9)(10)(11), however, a normal D-dimer cannot rule out a diagnosis of ischemic stroke in people (4). In dogs, cerebral venous occlusion is reported but is thought to be a rare cause of ischemia due to abundant anastomoses (26,27). ...
Ischemic stroke is a condition increasingly recognized in dogs; however, the number of publications on dogs with ischemic stroke is still limited and hemostatic parameters are infrequently reported. D-dimer levels have been shown to be elevated in people with acute ischemic stroke compared to a healthy control population and it has been proposed that a normal D-dimer can be used to exclude thromboembolism in dogs. In this case series, we report hemostatic parameters, including D-dimer and thromboelastography (TEG) along with clinical and imaging findings for five dogs diagnosed with ischemic stroke. All dogs had a normal D-dimer concentration on presentation. A hypercoagulable state was identified in two dogs based on the results of the TEG, and was suspected in the remaining three cases based on a shortened TEG clot reaction time. Based on the findings in the present cases, a D-dimer within the normal reference range does not seem an appropriate negative predictor for canine ischemic stroke. The demonstration of a possible hypercoagulable state, as identified by the TEG, is an interesting finding which should be explored further to help reveal predisposing hypercoagulable conditions in dogs with ischemic stroke.
... D-dimer was significantly associated with increased frequencies of stroke, stroke progression, and even death, regardless of stroke subtype in several studies. [7][8][9][10] However, one study showed that after excluding venous thrombosis in all stroke patients using imaging studies along with adjustment for confounding factors, neither stroke severity nor total anterior circulation infarction was associated with D-dimer levels, and only old age was significantly associated with D-dimer levels. 11 Because of these equivocal relationships of other stroke subtypes with D-dimer levels, in contrast to the robust significant association of D-dimer with cardioembolism, we evaluated the association between D-dimer levels and long-term functional outcomes in patients with acute lacunar and large artery atherosclerosis (LAA) infarctions. ...
... 17,21 In a previous study, D-dimer levels were related to the extent of neurological damage and disability. 10 In contrast, other studies found no correlation between D-dimer levels and stroke severity. 17,22,23 Our results are in accordance with latter studies, because once significantly different functional outcomes were set initially depending on the D-dimer levels, longitudinal temporal changes in functional outcomes were not influenced by D-dimer levels (no group × time effect). ...
Background:
Although D-dimer levels are significantly associated with cardioembolic infarction, the significance of D-dimer levels in relation to the severity and functional outcomes of other stroke subtypes, such as lacunar and large artery atherosclerosis infarction, remains unclear. The purpose of this study was to evaluate whether elevated initial D-dimer levels are significantly and cross-sectionally associated with poor functional outcomes at each time point during a 9-month follow-up period. We also investigated the significance of D-dimer levels in longitudinal temporal changes of functional outcomes in these patients.
Methods:
We recruited 146 patients with lacunar infarction and 161 patients with large artery atherosclerosis infarction who were consecutively admitted to our hospital after acute stroke. Serum D-dimer levels were evaluated initially and the modified Rankin scale were measured initially and at 1-, 3-, 6-, and 9-month follow-up visits.
Results:
Patients with higher D-dimer levels had significantly worse initial functional outcomes, and these worse outcomes were maintained throughout the 9-month follow-up period compared with the low D-dimer group. However, regardless of stroke subtype, D-dimer levels did not influence long-term changes in functional outcomes over the 9-month follow-up period.
Conclusion:
This study suggests that elevated D-dimer levels can be used as a surrogate marker for poor functional outcomes only during the acute stage. Further evaluation of serum D-dimer levels could provide a helpful predictive marker for stroke prognosis.
... It follows that the degradation of the thrombus is associated with a higher systemic D-dimer concentration. Several studies [55,68,69] showed that D-dimer levels are significantly higher in ischaemic strokes of cardioembolic origin than in those of noncardioembolic origin. ...
... In a further cohort study [69], mean D-dimer levels were 1.7 times higher in patients suffering from cardioembolic ischaemic stroke (1,287.50 ng/ml, n = 34) than patients suffering from noncardioembolic stroke (750.20 ng/ml, n = 42). ...
Each year, over 5 million people die worldwide from stroke, and at least every sixth patient who survives will experience another stroke within five years [1]. We are therefore eager to advance early and rapid diagnosis, prognosis and optimal risk stratification, as well as secondary prevention. In this context, blood biomarkers may improve patient care, as they have already done in other fields in the past, for example, troponin T/I in patients with heart attacks, natriuretic peptides in patients with heart failure or PCT (procalcitonin) [2] in patients with pneumonia. In the setting of acute stroke, a blood biomarker can be any quantifiable entity that reflects the manifestation of a stroke-related process. The most fruitful implementation of stroke biomarkers is in areas where information from traditional clinical sources is limited. There may be markers, for example, to guide risk stratification, reveal stroke aetiology, identify patients who may benefit most from interventions, monitor treatment efficacy, and recognise the risk of shortterm complications or unfavourable long-term outcomes. For this review we focus on blood biomarkers that could help distinguish the underlying aetiology of an ischaemic stroke. Stroke tends to be a much more heterogeneous condition than ischaemic heart disease, which is caused by atherosclerosis in the vast majority of cases. Causes of stroke include small and large vessel disease, cardioembolism, dissections, and rare vasculo- and coagulopathies, among others. Because of this heterogeneity among stroke patients, it is clear that a monolithic approach to stroke prevention or secondary prevention is not warranted. Aetiological classification is important specifically because prognosis, risk of recurrence and management options differ greatly between aetiological subtypes. Considering that today up to 30% of stroke patients still cannot be classified into a specific subtype [3], the ability to improve aetiological classification to direct prevention methods at the underlying mechanism would be of greatest interest. For this review we collected data from studies, on aetiological blood biomarkers in ischaemic stroke patients, listed in PubMed up to October 2014. We describe the potential role of 22 selected blood biomarkers in the context of stroke aetiology. Finally we provide the readers with an outlook in this research field.
... Among these biomarkers, BNP [10] is associated with cardiac disorders, and its use is increasing in clinical practice. Other authors have studied the role of hemostatic markers, platelet aggregation factors, or D-dimer associated with ischemic strokes [11][12][13]. ...
... The results of our study are in accordance with previous reports stating the usefulness of blood biomarkers in diagnosing the different etiological subtypes of ischemic stroke [8,9,11,12]; in this case, some of these biomarkers may help us to select which patients are more likely to have embolic features after the cardiological explorations within the first hours after the stroke. When designing the study, we selected some biomarkers used for cardioembolic disorders or previously related to cardioembolic stroke; among them BNP, which is a potential marker of heart failure and myocardial ischemia. ...
The risk of recurrent stroke is likely related to etiology. Therefore it is important to identify which patients are at highest early risk. We evaluated whether selected blood biomarkers may aid in the diagnosis of stroke etiology. We studied consecutive non-lacunar stroke patients between November 2006 and January 2007, and selected undetermined origin strokes. Blood samples were drawn at arrival to test brain natriuretic peptide (BNP), D-dimer, CK-MB, myoglobin, and troponin. Second harmonic transthoracic echocardiography (SHTTE) and ECG-24 h monitoring were also performed within the first 24 h. We evaluated 294 patients with ischemic stroke; 89 had an initial undetermined origin. After a cardiological work-up, 49 were diagnosed as embolic including atrial fibrillation (4), severe aortic arch atheromatosis (24), severe wall abnormalities (12), valve disease (3), dilated cardiomyopathy (1), and patent foramen (5). Higher levels of CK-MB, BNP, and myoglobin were found in patients with embolic source in SHTTE, but only CK-MB >1.5 ng/ml and BNP >64 pg/ml remained as independent predictors: BNP (OR 8.86; CI 95 % 2.79-28.09), CK-MB (OR 6.28; CI 95 % 1.66-23.69). BNP showed specificity of 75 %, sensitivity of 63.4 %, and positive predictive value (PPV) of 75.6 %. CK-MB had specificity of 85 %, sensitivity of 47.9 %, and PPV of 79.3 %. Measuring both biomarkers improves the finding of embolic source, increasing specificity to 95 % and PPV to 88.2 %. High-level CK-MB and BNP during the acute phase of ischemic stroke are associated with an embolic source. Measurement of both biomarkers may improve the diagnosis, guiding the need to perform a heart exploration.
... These findings are in concurrence with similar studies wherein the authors attempted to understand a relationship between D Dimer and acute ischemic stroke in case control format. (14,15) Some studies reported that variations in D Dimer levels occur when age and gender comes into play. This is also in concurrence with our study, wherein such features were noted. ...
Background: Acute ischemic stroke has been known to be a severely debilitating affliction with a steep disability and co morbidity curve. Various tools and methods have been attempted to ascertain if the diagnosis and prognosis of stroke can be achieved faster as it aids in effective management as well as reduces the resultant damage to the brain. Aim: The present study was designed to assess if serum D Dimer levels can be used as a marker as well as a volumetric determinant of stroke. Methods: The study involved a patient pool of 50 patients and corresponding controls who were matched for age and gender. The data collected included demographic data, baseline clinical parameters, serum D Dimer levels and a radiological assessment of the volume of infract. Findings: The study revealed that a relationship exists between the levels of circulating D Dimer and DW MRI weighted images showing infarcts. The relationship was direct in nature. Conclusion: D Dimer levels can provide a estimate of the area under infarction and thus prove to be a prognostic as well as diagnostic marker. Keywords: Acute ischaemic Stroke, D Dimer, Volumetric Association
... These findings are in concurrence with similar studies wherein the authors attempted to understand a relationship between D Dimer and acute ischemic stroke in case control format. (14,15) Some studies reported that variations in D Dimer levels occur when age and gender comes into play. This is also in concurrence with our study, wherein such features were noted. ...
Background: Acute ischemic stroke has been known to be a severely debilitating affliction with a steep disability and co-morbidity curve. Various tools and methods have been attempted to ascertain if the diagnosis and prognosis of stroke can be achieved faster as it aids in effective management as well as reduces the resultant damage to the brain. Aim: The present study was designed to assess if serum D Dimer levels can be used as a marker as well as a volumetric determinant of stroke. Methods: The study involved a patient pool of 50 patients and corresponding controls who were matched for age and gender. The data collected included demographic data, baseline clinical parameters, serum D Dimer levels and a radiological assessment of the volume of infract. Findings: The study revealed that a relationship exists between the levels of circulating D Dimer and DW MRI weighted images showing infarcts. The relationship was direct in nature. Conclusion: D Dimer levels can provide a estimate of the area under infarction and thus prove to be a prognostic as well as diagnostic marker. Keywords: Acute ischaemic Stroke, D Dimer, Volumetric Association
... High fibrinogen levels are correlated with an increased risk of AD and VaD (Xu et al., 2008). As for the blood biomarker of AIS, fibrinogen level is associated with the prognosis of AIS (Tombul et al., 2005). ...
Reliable quantitative blood biomarkers are important in vascular dementia (VaD) because early diagnosis and therapeutic intervention are effective in preventing progression of dementia. Although many blood biomarkers for acute ischemic stroke (AIS) or VaD have been reported, there are few reliable blood biomarkers. VaD and AIS have similar pathological conditions that are associated with small vessel disease (SVD) such as oxidative stress, inflammation, endothelial dysfunction, and neuronal injury. Therefore, it may be possible to find superior blood biomarkers of VaD among AIS blood biomarkers. Owing to recent developments, noncoding RNAs such as microRNA and long noncoding RNA, which can be analyzed using a single drop of blood, are also particularly reliable VaD markers because they stably reflect brain tissue damage. A multimarker combining several blood biomarkers or artificial intelligence technology may also be beneficial to compensate for insufficiencies of a single blood biomarker. This review describes the blood biomarkers of VaD and how they are related to blood biomarkers of AIS.
... Also, platelets with larger volume have higher metabolic and enzymatic activity than platelets with lower volume. In some studies, increased MPV was indicated to be associated with increased platelet activity and therefore, may be related to the severity and prognosis of stroke; the higher MPV may result in a worse outcome (8)(9)(10)(11)(12)(13)(14). ...
Background:
Stroke is known to be the third most prominent cause of death in the developing countries and the most common debilitating neurologic disease. This study aimed to investigate the association of platelet count (PC) and mean platelet volume (MPV) index with various stroke types.
Methods:
This cross-sectional study was carried out on patients over the age of 18 years who presented with signs and symptoms of the first acute stroke. Exclusion criteria were underlying chronic liver or renal disease and the time more than 6 hours from symptom initiation, hematological and infectious disorders in patients. After recording of demographic data, a complete blood cell count (CBC) test was performed.
Results:
From 150 patients, who enrolled in the study, 54.7% of patients were males. The initial brain CT scan was normal in 13 (8.7%) patients and showed evidence of brain infarction and intracranial hemorrhage in 84 (56%) and 53 (35.3%) patients respectively. Patients with intracranial hemorrhage had significantly higher mean of MPV index than the patients with normal brain-CT scan and patients with evidence of brain infarction (p<0.001).
Conclusion:
The MVP index can be a predictor of the type of hemorrhagic or ischemic finding in emergency CT scan in stroke patients. This relationship may help to better understand the physiopathologic role of platelets in the development of stroke (hemorrhagic or ischemic), but will not replace cerebral computed tomography to diagnose the type of stroke, or it may not initiate treatment for hemorrhagic stroke.
... D-dimer, a fibrinogen compound with high molecular weight, is formed during activation of the coagulation system and derived from the degradation of cross-linked fibrinogen (6). In vivo, the activation of the thrombosis and fibrination could be reflected by the appearance and elevation of plasma d-dimer, which appeared to be one of the most valuable evaluation parameters for the investigation of thrombolysis (7,8). ...
Background: The aim of our meta-analysis was to evaluate the association between plasma d-dimer and intracerebral hemorrhage (ICH).
Methods: Embase, Pubmed, and Web of Science were searched up to the date of March 19th, 2018, and manual searching was used to extract additional articles. Standard mean difference (SMD) with 95% confidence intervals (CI) was calculated to evaluate d-dimer levels.
Results: Thirteen studies including 891 ICH patients and 1,573 healthy controls were included. Our results revealed that higher levels of d-dimer were displayed in ICH patients than those in healthy controls (95% CI= 0.98–2.00, p< 0.001). Subgroup analysis based on continent of Asia and Europe, sample size, as well as age in relation to d-dimer levels between ICH patients and healthy controls did not change the initial observation; whereas no differences of d-dimer levels were found between ICH and controls in America.
Conclusions: This meta-analysis revealed that high level of d-dimer is associated with the risk of ICH. Plasma d-dimer is suggested to be a potential biomarker for patients with ICH in Asia and Europe rather than in America. There were no impact of sample size-related differences and age-related diversities on the risk of ICH with respect to d-dimer levels.
... [40] Ek olarak, d-dimer yüksekli- ¤inin mortalite ile iliflkili oldu¤u saptanm›flt›r. [41,42] Bizim çal›flmam›zda da bu bulgulara paralel sonuçlar elde edil- mifltir. Ölen hastalarda taburcu olan hastalara göre d-dimer de¤erleri anlaml› olarak daha yüksek saptand›. ...
... 11,12 Our findings in terms of D-dimer are in line with previous studies and the recent subanalysis study of the ENGAGE AF-TIMI 48 trial showing that a higher D-dimer value was associated with increased risk for adverse cerebrovascular events. 4,[13][14][15][16][17] Several researchers have also reported the cross-sectional association between D-dimer levels and stroke severity in prior studies. [18][19][20] However, most of these cross-sectional studies included the patients with ischemic stroke from heterogeneous etiologies and did not focus only on the cardioembolic stroke. ...
Background A subanalysis study of the ENGAGE AF-TIMI 48 trial showed that cardiac troponin I, N-terminal proB-type natriuretic peptide, and D-dimer, were powerful predictors of cerebrovascular adverse events. We aimed to evaluate D-dimer and cardiac troponin I levels during the acute period of ischemic stroke in anticoagulation-naïve patients with non-valvular atrial fibrillation (NVAF) and also studied the association between these biomarkers and stroke severity. Methods Consecutive anticoagulation-naïve patients with acute ischemic stroke due to NVAF were enrolled within two days after each stroke event, and all patients were stratified into either moderate-to-severe or mild neurologic deficit groups using the National Institutes of Health Stroke Scale (NIHSS) at admission. Results A total of 98 patients were enrolled in this study. The median value for the D-dimer was above the upper limit of the normal reference range, but the troponin I value was within the normal range for all patients. After adjusting for CHA2DS2-VASc risk factors, the log-transformed values for D-dimer were positively correlated with an increasing NIHSS score (r=0.233; P=0.051). In the multivariate logistic analysis, the log-transformed D-dimer was positively associated with more severe strokes (odds ratio, 30.1; 95% confidence interval [CI], 1.9-486.2 and 29.7; 95% CI, 2.0-430.8 in the upper two quartiles respectively). The log-transformed values for troponin I did not correlate with the NIHSS score. Conclusion D-dimer levels were higher and an independent risk factor for severe stroke in anticoagulation-naïve patients with NVAF related stroke. In contrast, troponin I levels were normal and were not associated with stroke severity.
... The serum Ddimer level could be helpful for refining the clinical risk stratification for predicting a stroke and thromboembolism in patients with AF. The D-dimer level has been reported to be significantly associated with increased frequencies of stroke, stroke progression and even death (19)(20)(21)(22)(23). ...
Objective Left atrial enlargement (LAE) may predispose individuals to blood stasis in atrial fibrillation (AF), and thus play a crucial role in thrombogenesis. The D-dimer level is one of the surrogate markers for a hypercoagulable state and reflects thrombus formation in AF. Since the D-dimer level reflects hypercoagulability as well as thrombus and fibrin burdens, LAE could be associated with a D-dimer elevation. However, no studies have explored this association or which factors contribute to increases in the D-dimer levels in patients with AF. Therefore, we assessed whether the serum D-dimer levels are related to the left atrial volume index (LAVI) or other vascular risk factors and also evaluated the association between the D-dimer levels and the initial stroke severity. Methods Ninety-eight consecutive patients with an acute ischemic stroke and non-valvular AF (NVAF) who were anticoagulation-naïve were enrolled, and all patients were stratified into moderate-to-severe and mild neurologic deficit groups using the National Institutes of Health Stroke Scale on admission. The association between the initial serum D-dimer levels and the LAVI was evaluated in all enrolled patients, and the serum D-dimer levels were compared between the two groups. Results The patients were classified into two groups according to the severity of the neurologic deficit. In a partial correlation coefficient analysis adjusted for confounding factors, an increase in the initial serum D-dimer levels was significantly associated with LAVI (r=0.286; p=0.027). A linear regression analysis showed that a history of peripheral artery disease was the factor most strongly associated with the serum D-dimer level (t=3.90, p<0.001), followed by LAVI (t=2.37, p=0.021) and a history of congestive heart failure (t=2.16, p=0.035). The D-dimer levels were higher in the moderate-to-severe neurologic deficit group than in the mild deficit group, but this difference was not statistically significant (4.5±7.1 vs. 1.6±2.6 mg/L, p=0.068). Conclusion The serum D-dimer levels were significantly associated with LAE in anticoagulation-naïve patients with an acute ischemic stroke and NVAF.
... Plasmin separates the fibrin into FDP and DD when the coagulation and the fibrinolytic system is triggered. Many types of researches proved that DD, C-reactive protein, and other markers of hemostatic activation linked to diagnosis [33][34][35][36][37][38][39][40][41], progression, and death in AICS patients [33,[42][43][44]. Laskowitz et al. [45] stated that a biochemical marker list could give time-sensitive and beneficial characteristic data to AICS appraisal and fast detection of cases with suspected AICS, that could widen the accessibility of time-limited therapeutic approaches. ...
... The reference value of plasma DD measured using ELISA was below 200 ng/mL. A number of studies have confirmed that the plasma level of DD increases in patients with acute ischemic stroke compared with healthy people [15,16]. ...
The aim of this study was to evaluate the diagnostic value of the serum biochemical markers high-sensitivity C-reactive protein (hs-CRP), D-dimer (DD) and fibrinogen (Fg) in differentiating etiological subtypes of ischemic stroke. This study was a retrospective case-only study, consecutively including patients with acute ischemic stroke. All patients were classified into subtypes using the TOAST classification system. A total of 317 patients were evaluated. Hs-CRP and DD levels were significantly different among the subtypes and were the highest in CE, followed by LAA and SAA; no significant difference between the subtypes was found for Fg. Hs-CRP > 6.96 mg/L was classified as the CE subtype, with a sensitivity of 41% and a specificity of 74%; DD > 791.30 ng/mL was classified as CE, with a sensitivity of 58% and a specificity of 78%. The combination of hs-CRP and DD classification as CE yielded a sensitivity of 65% and a specificity of 91%. DD > 791.30 ng/mL was considered an independent predictive factor of CE. Hs-CRP and DD could be useful for identifying the etiological subtypes of acute ischemic stroke, especially for predicting CE. The diagnostic value of DD was higher than that of hs-CRP.
... Not known Not known CXCL4 Increased in plasma from stroke patients and higher levels associated with disability [ 61 ]. CXCL4 levels diminished along time [ 62 ]. ...
Chemokines act mainly in guiding leukocyte migration along the endothelium. Apart from angiogenesis or neuronal survival, chemokines are involved in damage and repair of brain tissue after ischemic stroke. We studied the presence of chemokines directly in neurons and brain blood vessels that were obtained by means of laser microdissection from human ischemic brains. Using multiple ELISA Searchlight® array we evaluated nine chemokines (CCL1−5, CCL11, CCL17, CCL22, and CXCL8) in microdissected samples. We found higher levels of CCL1 and CCL2 in neurons than in vessels; CCL5 and CCL22 were decreased in the infarcted areas.
The same ELISA array was performed in plasma samples from stroke patients. We explored the temporal profile of circulating chemokines from admission to 90 days after the cerebrovascular event, and found that only CCL22 showed significant changes along time and that these changes negatively correlated with neurological severity. When neurological outcome was assessed in the hyperacute phase of stroke no associations were found.
From our study, we can conclude that these chemokines do not perform a clear role of outcome biomarkers. Further studies are necessary to assess which mechanisms underlie the association of chemokines with the neurological state at distinct time points since the differences found here could be reflecting the dual role of chemokines in neuroinflammation.
... D-dimer, a breakdown product of fibrin, is one of the basic markers of fibrinolytic system activity. It is not only elevated in plasma taken from patients with atrial fibrillation (AF) -most common cardiac abnormality leading to stroke-but also has been found raised in CE stroke patients compared with other etiologies [22][23][24]. A recent study, conducted by Alvarez-Perez and collaborators with 200 stroke patients and 50 controls, shows a thrombogenic profile in patients with CE stroke characterized by higher D-dimer levels than LAA, SVD or undetermined etiologies (p<0.0001) ...
Stroke is one of the main causes of death and disability in the world. Cardioembolic etiology accounts for approximately
one fifth of all ischemic strokes whereas 25-30% remains undetermined even after an advanced diagnostic
workup. Despite there is not any biomarker currently approved to distinguish cardioembolic stroke among other etiologies
in clinical practice the use of biomarkers represents a promising valuable complement to determine stroke etiology reducing
the number of cryptogenic strokes and aiding in the prescription of the most appropriated primary and secondary
treatments in order to minimize therapeutic risks and to avoid recurrences. In this review we present an update about specific
cardioembolic stroke-related biomarkers at a protein, transcriptomic and genetic level. Finally, we also focused on
reported biomarkers associated with atrial fibrillation (a cardiac illness strongly related with cardioembolic stroke subtype)
thus with a potential to become biomarkers to detect cardioembolic stroke in the future.
... Our findings were consistent with results of previous prospective studies showing that D-dimer levels were elevated in the acute phase of AIS compared with the healthy control population [22][23]. Smith et al [24] reported that D-dimer could predict incident stroke in the general population, even though no significant association was seen in the Three-City French cohort study [25]. ...
It has been suggested that modestly elevated circulating D-dimer values may be associated with acute ischemic stroke (AIS). Thus, the purpose of this study was to investigate the association between plasma D -dimer level at admission and AIS in Chinese population.
In a prospective observational study, plasma D-dimer levels were measured using a particle-enhanced, immunoturbidimetric assay on admission in 240 Chinese patients with AIS. The National Institutes of Health Stroke Scale (NIHSS) score was assessed on admission blinded to D-dimer levels.
Plasma median D-dimer levels were significantly (P = 0.000) higher in AIS patients as compared to healthy controls (0.88; interquartiler range [IQR], 0.28-2.11 mg/L and 0.31; IQR, 0.17-0.74 mg/L). D-dimer levels increased with increasing severity of stroke as defined by the NIHSS score(r = 0.179, p = 0.005) and infarct volume(r = 0.425, p = 0.000). Those positive trends still existed even after correcting for possible confounding factors (P = 0.012, 0.000; respectively). Based on the Receiver operating characteristic (ROC) curve, the optimal cut-off value of plasma D-dimer levels as an indicator for diagnosis of cardioembolic strokes was projected to be 0.91 mg/L, which yielded a sensitivity of 83.7% and a specificity of 81.5%, the area under the curve was 0.862(95% confidence interval [CI], 0.811-0.912).
We had shown that plasma D-dimer levels increased with increasing severity of stroke as defined by the NIHSS score and infarct volume. These associations were independent other possible variables. In addition, cardioembolic strokes can be distinguished from other stroke etiologies by measuring plasma D-dimer levels very early (0-48hours from stroke symptom onset).
... Conventionally, elevated plasma levels of plasma PF4 and beta-TG are used as indicators of platelet activation. Increased plasma levels of both PF4 and beta-TG have been proposed to be used as diagnostic/prognostic biomarkers for various kinds of diseases, such as diagnosis of megakaryoblastic leukemia [30], prediction of thrombotic complications in patients with artificial heart valves [31], prognosis of cerebral infarction [32,33], etc. Moreover, it is not uncommon that plasma/serum proteomic profiling identified an alternated plasma/serum level of only either PF4 or beta-TF level, but not both, as a potential diagnostic/prognostic biomarker. ...
Previously, we reported that proteomic fingerprints were present in sera of patients with severe acute respiratory syndrome (SARS), and could separate patients into subgroups with different prognoses. In the present study, we examined the prognostic values of the SARS-associated proteomic features by biostatistical analysis, and deciphered the identities of those with prognostic values. Data of 20 SARS-associated serum proteomic features and ten serological variables from 38 SARS adult patients before treatment were subjected to multivariate logistic regression. Proteomic features of m/z 6634, m/z 7769, m/z 8635, and m/z 8865 were identified as independent prognostic markers. After purification by cation-exchange chromatography and gel electrophoresis, proteomic features of m/z 7769 and m/z 8865 were found to be platelet factor 4 (PF4) and beta-thromboglobulin (beta-TG) by tandem mass spectrometry, respectively. The associations of decreased serum PF4 and increased serum beta-TG levels with poor prognosis were confirmed by Western blot. Previous studies suggest that PF4 and beta-TG are involved in the pathogenesis of acute respiratory distress syndrome (ARDS) in a negative and positive way, respectively. Our results suggest that PF4 and beta-TG may also play similar roles in the development of ARDS in SARS patients.
A State of the Art lecture titled "coagulation biomarkers for ischemic stroke" was presented at the International Society on Thrombosis and Haemostasis (ISTH) Congress in 2022. Ischemic stroke (IS) is a common disease with major morbidity and mortality. It is a challenge to determine which patients are at risk for IS or have poor clinical outcome after IS. An imbalance of coagulation markers may contribute to the progression and prognosis of IS. Therefore, we now discuss studies on the association of selected coagulation biomarkers from the hemostasis, inflammation, and immunothrombosis systems with the risk of IS, stroke severity at the acute phase, and clinical outcome after treatment. We report on coagulation biomarker-induced risk of IS, stroke severity, and outcomes following IS derived from prospective population studies, case-control studies, and acute-phase IS studies. We found indications that many coagulation and inflammation biomarkers are associated with IS, but it is early to conclude that any of these biomarkers can be applied in a therapeutic setting to predict patients at risk of IS, stroke severity at the acute phase, and clinical outcome after treatment. The strongest evidence for a role in IS was found for beta-thromboglobulin, von Willebrand factor, factor VIII, fibrinogen, thrombin-activatable fibrinolysis inhibitor, D-dimer, and neutrophil extracellular traps, and therefore, they are promising candidates. Further research and validation in large-size populations using well-defined study designs are warranted. Finally, we provide a selection of recent data relevant to this subject that was presented at the 2022 ISTH Congress.
Background
The present study aimed to examine whether variables including D-dimer, high-sensitivity C-reactive protein (hsCRP), hemoglobin, platelet count, and nutritional status mediate the pathway between cancer and ischemic stroke outcomes.
Methods
We reviewed data from consecutive patients with ischemic stroke admitted to Osaka University Hospital between January 1, 2006, and December 31, 2016. Patients with ischemic stroke were grouped according to the presence of cancer. Nutritional status was assessed using Controlling Nutritional Status (CONUT) scores. Mediation analyses were utilized to address the study aims.
Results
Among 1,570 patients with ischemic stroke, 185 (12%) had active cancer. Relative to patients with ischemic stroke in the non-cancer group, those in the cancer group exhibited higher National Institutes of Health Stroke Scale scores on admission, higher D-dimer and hsCRP levels, lower hemoglobin levels and platelet counts, higher CONUT scores, and poorer modified Rankin Scale scores at discharge. Mediation analysis revealed that D-dimer, hsCRP, hemoglobin, platelet count, and CONUT scores acted as mediators of poor prognosis in the cancer group. The association between the exposure and outcome variables was no longer significant in the models containing D-dimer and CONUT scores as mediator variables, suggesting that they were strong mediators. Regarding the association between the mediator and outcome variables, hemoglobin, platelet count, and CONUT exhibited non-linearity (p for non-linearity < 0.001).
Conclusions
D-dimer, hsCRP, hemoglobin, platelet count, and CONUT score act as mediators of poor prognosis in patients with ischemic stroke with comorbid cancer. Such abnormalities can help to predict ischemic stroke outcomes.
A rise in the number of young and old patients suffering from a stroke or traumatic brain injury has led to the need for better drug development and treatment, as well as diagnosis and prevention of ischemic stroke and traumatic brain injury. This book provides a comprehensive overview of scientific advancements in these areas.
Chapters provide the latest knowledge in neuroscience, biotechnology, and personalized medicine applicable to acute brain injuries. Development of neuroprotective drugs is treated in detail. Chemical biomarkers for detection, imaging and preventative strategies are covered to provide medicinal chemists with a broad view of translational aspects of the field.
This book will be useful to postgraduate students and researchers in medicinal chemistry and pharmacology as well as specialists in the acute brain injury field.
Interest in biological markers (biomarkers) for personalized medicine and public health has recently increased, because they provide a cost-effective and objective means of screening patients for various disease processes in a timely, accurate, and reproducible fashion. In addition, biomarkers are increasingly utilized for their ability to provide diagnostic information to help guide the management of acute disease. Despite significant advances in the diagnosis and treatment of acute brain injuries, the early diagnosis and evaluation of prognosis and treatment efficacy remains challenging. In patients who experience ischemic stroke or hemorrhagic stroke from subarachnoid hemorrhage (SAH), high-quality biomarkers in the blood and cerebrospinal fluid are gaining increasing evidence-based traction for use in monitoring brain injury evolution and response to therapy. In addition to a comprehensive analysis of the current evidence supporting biomarkers for SAH and stroke, we discuss the persisting need for additional reliable biomarkers of neurological disease, the process of biomarker and point-of-care test development, and the importance of continued research in the area of biomarkers, particularly as it applies to cerebrovascular pathology.
Background The objective of the study was to evaluate the predictive value of plasma D-dimer at admission after acute ischemic stroke, and to assess its effect on short-term functional outcome. Methods Fasting plasma D-dimer was measured in 290 consecutive patients (61.7% men, mean age 67.0±12.3 years) within 3 days after the onset of acute ischemic stroke. The outcomes were measured at 3-months after stroke onset, by the modified Rankin Scale (mRS). Results Atrial fibrillation, hypertension, diabetes and involvement of the insular cortex, the levels of serum high sensitive C-reactive protein and D-dimer, as well as incidence of women and age, were all significantly higher in the poor outcome group (P
Acute brain injury as a result of stroke and traumatic brain injury are leading causes of disability and mortality. Methods to improve patient diagnosis and prognosis for these common conditions are needed. Molecular biomarkers are one method that has been evaluated to diagnose acute brain injury, determine its cause, and predict outcomes and response to therapy. Markers that have been identified include a variety of proteins, nucleic acids, and lipids that relate to the pathophysiology of acute brain injury. Inflammation plays an important role in acute brain injury and several molecules involved in inflammation have been identified as biomarkers. However, biomarkers for acute brain injury is a developing field that requires additional study is to identify markers for use in clinical practice. These studies will include evaluating a larger number of candidate markers using proteomic, genomic, metabolomic, and lipidomic approaches. Additionally, novel markers such as microRNA and the use of panels that integrate multiple markers may also prove to be valuable tools in acute brain injury. In this chapter, we provide a summary of identified inflammatory biomarkers in acute brain injury, and how these biomarkers could add to patient care.
Biomarkers provide critical mechanistic insights to key biologic processes that occur during cerebral ischemia which, when carefully applied, can improve clinical decision-making in acute stroke management. The translation of a blood-based biomarker in ischemic stroke to clinical practice is challenging, in part, due to the complexity of ischemic stroke pathogenesis and the presence of a blood-brain barrier that restricts the release of brain-specific markers into the circulation. The pathologic and clinical aspects of ischemic stroke are described in this review, where a non-exhaustive list of biomarkers that interrogate different aspects of ischemic stroke such as oxidative damage, inflammation, thrombus formation, cardiac function and brain injury are described. The potential roles of these biomarkers are further examined under different clinical scenarios aimed at (1) averting the risk of hemorrhagic transformation, (2) identifying individuals at risk of early neurologic deterioration and malignant infarction, (3) aiding in the diagnosis of ischemic stroke and its differentiation from other stroke mimics, (4) guiding the search for stroke etiology, and (5) assessing stroke risk within the community. Researchers should explore the roles of stroke biomarkers to enhance clinical decision-making that is presently largely based on intuition and subjective reasoning.
Background:
Despite being an important cause of death and functional disability, acute cerebral infarction (ACI) lacks accurate and easy tools to predict the outcome of patients beyond clinical variables such as age and stroke severity.
Methods:
To investigate if plasma D-dimer level can be used as such a prognostic biomarker for ACI, so as to better guide patients' management, we studied the association between plasma D-dimer and the functional recovery of 1173 ACI patients. The patients were divided into 2 groups according to modified Rankin Scale (mRS) scores or National Institutes of Health Stroke Scale (NIHSS) scores evaluated on the 30th day after onset.
Results:
We observed that plasma D-dimer level correlated significantly with the prognosis of ACI evaluated based on both mRS scores (389.68 ± 32.06 µg/L for poor prognosis versus 377.70 ± 32.68 µg/L for good prognosis, P < .001) and NIHSS scores (387.01 ± 30.60 µg/L for poor prognosis versus 375.23 ± 30.66 µg/L for good prognosis, P < .01). Logistic analysis confirmed that higher D-dimer level was a risk factor for poor prognosis (mRS: odds ratio [OR], 1.604; 95% confidence interval [CI], 1.360-1.892; P < .001; NIHSS: OR, 1.733; 95% CI, 1.461-2.056; P < .01), after adjusted for age, gender, hypertension, diabetes, smoking, and hyperlipidemia.
Conclusion:
Our results show that plasma D-dimer level is a promising prognosis biomarker for ACI.
A rapid and reliable diagnostic test to distinguish ischemic from hemorrhagic stroke in patients presenting with stroke-like symptoms is essential to optimize management and triage for thrombolytic therapy. The present study measured serum concentrations of ubiquitin C-terminal hydrolase (UCH-L1) and glial fibrillary astrocytic protein (GFAP) in acute stroke patients and healthy controls and investigated their relation to stroke severity and patient characteristics. We also assessed the diagnostic performance of these markers for the differentiation of intracerebral hemorrhage (ICH) from ischemic stroke (IS). Both UCH-L1 and GFAP concentrations were significantly greater in ICH patients than in controls (p < 0.0001). However, exclusively GFAP differed in ICH compared with IS (p < 0.0001). GFAP yielded an AUC of 0.86 for differentiating between ICH and IS within 4.5hrs of symptom onset with a sensitivity of 61% and a specificity of 96% using a cut-off of 0.34ng/ml. Higher GFAP levels were associated with stroke severity and history of prior stroke. Our results demonstrate that blood UCH-L1 and GFAP are increased early after stroke and distinct biomarker-specific release profiles are associated with stroke characteristics and type. We also confirmed the potential of GFAP as a tool for early rule-in of ICH, while UCH-L1 was not clinically useful.
In ischemic stroke patients, blood-based biomarkers may be applied for the diagnosis of ischemic origin and subtype, prediction of outcomes and targeted treatment in selected patients. Knowledge of the pathophysiology of cerebral ischemia has led to the evaluation of proteins, neurotransmitters, nucleic acids and lipids as potential biomarkers. The present report focuses on the role of blood-based biomarkers in the early stage of ischemic stroke—within 72 h of its onset—as gleaned from studies published in English in such patients. Despite growing interest in their potential role in clinical practice, the application of biomarkers for the management of cerebral ischemia is not currently recommended by guidelines. However, there are some promising clinical biomarkers, as well as the N-methyl-d-aspartate (NMDA) peptide and NMDA-receptor (R) autoantibodies that appear to identify the ischemic nature of stroke, and the glial fibrillary acidic protein (GFAP) that might be able to discriminate between acute ischemic and hemorrhagic strokes. Moreover, genomics and proteomics allow the characterization of differences in gene expression, and protein and metabolite production, in ischemic stroke patients compared with controls and, thus, may help to identify novel markers with sufficient sensitivity and specificity. Additional studies to validate promising biomarkers and to identify novel biomarkers are needed.
Background: Fibrinogen is a powerful predictor of vascular events in health populations and patients with cardiovascular disease. There is great evidence suggesting that patients suffering ischemic stroke has significantly higher plasma fibrinogen levels, these levels are associated with increased risk of ischemic stroke as well as significant prognostic influence in stroke patients. Objective: The objective of this study is to correlate the plasma fibrinogen levels with clinical outcome in patients with acute ischemic stroke. Methods: Thirty-five consecutive patients with acute ischemic stroke were evaluated within the first 48 hours of onset of symptoms and after three months duration. Serum fasting plasma fibrinogen level was measured within 48 hours of onset of symptoms. Results: Plasma fibrinogen levels were high in patients with ischemic stroke and ranged from 1.8 to 8.2 g/l with a mean of 5.33 g/l (S.D ±1.77). Twentyfive patients (71%) patient had plasma fibrinogen level >4.5 g/l and ten patients (29%) with fibrinogen levels ≤ 4.5 g/l. High fibrinogen levels were associated with poor outcome three months post stroke and the most prevalent risk factor was hypertension. Conclusion: There is association between plasma fibrinogen level and ischemic stroke. Elevated fibrinogen levels were predictive of poor outcome.
Little is known, in man, in the post-thrombolytic molecular dynamics of haemostasis, particularly the effect of rt-PA on antifibrinolytic components such as alpha2 anti-plasmin and Factor XIII.
The purpose of this study was to systematically determine changes in coagulation and fibrinolytic parameters after thrombolysis with rt-PA during 24h. We also aimed to correlate these parameters with different acute ischemic stroke subtypes and global outcome.
Eighty consecutive patients with cerebral infarcts treated with rt-PA had their plasma levels of fibrinogen, plasminogen, alpha2-antiplasmin, Factor XIII, fibrin(ogen) degradation products (FDP) and D-Dimers measured at baseline (h0), 2 (h2) and 24h (h24) after initiation of thrombolysis. Correlations between the variations of these components were statistically studied, using the Spearman rank test or the Pearson test. These haemostatic parameters were also compared with cardioembolic and non cardioembolic patients, as well as between poor and favourable outcome patients.
Between h0 and h2, a decrease in fibrinogen, plasminogen, alpha2-antiplasmin, and factor XIII was observed, while an increase in FDP and D-Dimers took place. These values returned to the initial levels at h24. At 2h, the decrease in fibrinogen was significantly correlated with that of plasminogen (0.48, p=0.01), alpha2-antiplasmin (0.48, p=0.004), and factor XIII (0.44, p=0.01); the decrease in plasminogen was significantly correlated with those of antifibrinolytic components, factor XIII (0.47, p=0.02) and alpha2-antiplasmin (r=0.77, p<0.001). These variations were independent of NIHSS. Cardioembolic infarcts showed a statistically significant greater h0-h2 decrease in plasminogen (p=0.04) and an h0-h2 increase in FDP (p=0.02). Poor outcome was linked to low plasminogen values at 2 and 24h.
Supposed to be fibrin-specific, rt-PA induces a decrease in circulating fibrinogen, significantly linked to a decrease in plasminogen. A collateral increase in antifibrinolytic agents such as factor XIII and alpha2-antiplasmin is also observed. At 2h, a significant decrease in plasminogen and a significant increase in fibrin(ogen) degradation products (FDP) are observed in cardioembolic infarcts, and appear as early independent predictors of this aetiology. A low plasminogen value at 2h is potentially predictive of poor prognosis at 3months.
Copyright © 2015 Elsevier B.V. All rights reserved.
Ischemic stroke is a leading cause of adult disability and mortality. With over 15 million strokes occurring every year in the world, methods to better identify patients at risk for stroke are needed, as are methods to improve patient diagnosis and prognosis when stroke occurs. Use of blood-based biomarkers is one method that has been evaluated to predict risk of stroke, diagnose stroke and its causes, predict stroke severity and outcome, and guide prevention therapy. Markers that have been identified include a variety of proteins, nucleic acids and lipids that relate to stroke pathophysiology. The role of blood biomarkers in ischemic stroke is still being defined, and further study is needed to develop blood biomarkers for clinical stroke use. In this review, the authors provide a summary of biomarkers that have been divided by their potential clinical application.
In clinical settings, cerebral infarct is a common disease of older adults, which usually increases the risk of cognitive impairment. This study aims to assess the quantitative electroencephalography (qEEG) as a predictive biomarker for the development of cognitive impairment, post-cerebral infarcts, in subjects from the Department of Neurology. They underwent biennial EEG recording. Cerebral infarct subjects, with follow-up cognitive evaluation, were analyzed for qEEG measures of background rhythm frequency (BRF) and relative δ, θ, α, and β band power. The relationship between cognitive impairment and qEEG, and other possible predictors, was assessed by Cox regression. The results showed that the risk hazard of developing cognitive impairment was 14 times higher for those with low BRF than for those with high BRF (P < .001). Hazard ratio (HR) was also significant for more than median θ band power (HR = 5, P = .002) compared with less than median θ band power. The HRs for δ, α, and β bands were equal to the baseline demographic, and clinical characteristics were not significantly different. In conclusion, qEEG measures of BRF, and relative power in θ band, are potential predictive biomarkers for cognitive impairment in patients with cerebral infarcts. These biomarkers might be valuable in early prediction of cognitive impairment in patients with cerebral infarcts.
Assessment of platelet activation after ischemic stroke could be clinically valuable if platelet markers existed that predict the risk of recurrent events and reflect the effect of antiplatelet therapy. Recently developed techniques such as the detection of activation-dependent neoantigens on the platelet surface by flow cytometry, the platelet function analyzer (PFA), or whole blood aggregometry represent methods that in the future could become helpful tools in stroke care. Studies showed an increased expression of activation-dependent markers such as CD62p (p-selectin) or CD63 after ischemic stroke, however, for these and other parameters it remains unclear whether an increased expression at any time point after stroke heralds an increased risk of future events. Sufficiently powered studies on the predictive value of platelet activation parameters and on effects of antiplatelet agents on these parameters after stroke are required in order to validate the potential clinical usefulness of these recently developed techniques.
Background: Although levels of D-dimer and fibrinogen/fibrin degradation products (FDP) are low in the circulation of healthy individuals, their levels are significantly elevated in patients with thromboembolic diseases. The aim of this study was to investigate the clinical utilities of D-dimer and FDP in the early diagnosis of stroke subtypes and the prediction of early prognosis. Methods: Hospitalized patients due to acute ischemic stroke underwent m easurement of plasma levels of D-dimer and FDP within 12 hours after admission. Stroke severity was assessed on admission and 2 weeks later using the National Institutes of Health Stroke Scale (NIHSS). Stroke subt ypes were classified according to the criteria of the Trial of ORG 10172 in Acute Stroke Treatment criterion. Results: D-dimer and FDP levels were significantly higher in the cardioembolic group than in the atherosclerotic and lacunar groups. There was independent correlation between the level of FDP and cardioembolism. Ninety-six patients showed clinical improvement that was defined by a redu ction of more than 4 points on the NIHSS two weeks later compared with that on admission. The level of D-dimer was higher in patients with clinical im- provement than in patien ts without improvement (p =0.032). However, there was no correlation between the level of D-dimer and early improvement. Conclusions: These results show that measurement of FDP in acute ischemic stroke could be helpful in subtype classification. However, D-dimer and FDP were not related with early prognosis. J Korean Neurol Assoc 26(2):123-127, 2008
Sickle cell anemia (SCA) is an autosomal recessive disorder, with Mendelian inheritance pattern, caused by a missense mutation in the β-polypeptide chain of the hemoglobin B. SCA preferentially affects populations in countries where malaria was/is present (e.g. Africa, USA, Brazil). Thereby, in USA, the incidence of SCA is relatively high, around 1/500, and the prevalence is about 1/1000. In Brazil, SCA represents a major public health problem with an incidence ranging from 1/2000 to 1/600 depending on the regions. Homozygotic patients present more severe medical conditions and reduced life expectancy than heterozygous individuals who generally are asymptomatic. Eventually, this life-threatening disease displays a complex etiology owing to heterogeneous phenotypes and clinical outcomes, subsequently affecting the management of the patients. One of the most critical complications associated with SCA is stroke, a leading neurologic cause of death and disability. About 24% of SCA patients have a stroke by the age of 45 and 11% by the age of 20. From the general population, twin and familial aggregation studies as well as genome-wide association studies (GWAS), mostly in pediatric populations with ischemic stroke, showed that the risk of stroke has a substantial genetic component. Nevertheless, to fully characterize genomic contributors of stroke and permit reliable personalized medicine, multidisciplinary studies incorporating knowledge from clinical medicine, epidemiology, genetics, and molecular biology, are required. In this manuscript, stroke in SCA patients is extensively reviewed with emphasis to the US and Brazilian populations. Recent advances in genomics analysis of stroke in SCA patients are highlighted.
Background:
Plasma D-dimer level may reflect the activity of thrombus formation in the left atrium of patients with nonvalvular atrial fibrillation (NVAF). Proper anticoagulation with warfarin dramatically decreases the rate of cerebral embolism, reduces stroke severity and subsequent risk of death, as well as the level of D-dimer in NVAF patients. However, the predictive value of D-dimer level on cerebral embolism severity has not been examined. Thus, the purpose of this study was to investigate the association between plasma D-dimer level at admission and infarct size in NVAF patients.
Methods:
We identified 124 patients with consecutive ischemic stroke and NVAF who were admitted within 48 h of symptom onset. We measured infarction volume from CT taken after 3 ± 1 days from the onset. Plasma D-dimer levels were measured at the time of admission. Relationships were analyzed between infarction volume and plasma D-dimer levels, cardiovascular risk factors, preadmission medications and admission conditions. We also assessed the influence of D-dimer level on functional outcome in patients with preadmission modified Rankin Scale (mRS) score of 0-1 and patients by tertile of D-dimer level (≤0.83, 0.83-2.16 and ≥2.16 µg/ml).
Results:
Infarction volume significantly correlated with D-dimer level (r = 0.309, p < 0.001), systolic blood pressure (r = 0.201, p = 0.026), diastolic blood pressure (r = 0.283, p = 0.002), National Institutes of Health Stroke Scale (NIHSS) score on admission (r = 0.546, p < 0.001) and mRS score at discharge (r = 0.557, p < 0.001). Multivariate regression analyses showed that the D-dimer level was significantly associated with infarction volume after adjusting for age, sex, current smoker or not, prothrombin time-international normalized ratio ≥1.6, diastolic blood pressure, CHADS(2) score and NIHSS score on admission. In patients with a preadmission mRS score of 0-1 (n = 108), D-dimer level was significantly associated with NIHSS score at admission (r = 0.318, p < 0.001) and mRS score at discharge (r = 0.310, p = 0.001). Patients in the highest D-dimer tertile group showed worse outcome than those in the middle (p = 0.041) and lowest (p < 0.001) tertiles.
Conclusions:
Plasma D-dimer level on admission is significantly related to infarction volume and functional outcome, following cardioembolic stroke in NVAF patients.
Aims:
This study was conducted to evaluate the clinical and MRI profiles in acute cancer strokes, and to demonstrate our experience with thrombolytic therapy in cancer stroke patients.
Methods:
We prospectively studied active cancer patients with acute ischemic stroke who underwent MRI within 48 h of the onset of symptoms. Patients were grouped based on the presence of conventional stroke mechanisms (CSM). Clinical characteristics and MRI profiles were evaluated.
Results:
A total of 70 patients were finally included in this study. Patients without CSM were more frequently presented with encephalopathy than those with CSM (29.4 vs. 2.8%, p = 0.002). The diffusion-perfusion mismatch pattern was more prevalent in patients with CSM (21 patients, 58.3%) than in patients without CSM (8 patients, 23.5%). Patients who had a higher tertiles of D-dimer level were significantly less likely to have the diffusion-perfusion mismatch pattern (p = 0.015). Among patients who presented within 6 h of the onset of stroke, revascularization therapy was performed in 4 of 16 (25%) patients with CSM, but none of the patients without CSM.
Conclusion:
Based on the stroke mechanisms, the optimal strategy of thrombolytic therapy should be considered differently in cancer patients with acute ischemic stroke.
The development of a clinically validated biomarker of acute cerebral ischemia would have the potential to facilitate the use of time-sensitive reperfusion strategies, allow for individualization of patient care by predicting relative risk of hemorrhage and volume of penumbral tissue, and add valuable prognostic information for patients presenting with acute stroke. Additionally, a stroke biomarker might benefit early stage clinical research by serving as a surrogate measure of ischemic injury. Although at present there are no clinically validated biomarkers of acute stroke, previous studies have focused on markers associated with different components of the ischemic cascade, including microglial activation, inflammation, oxidative stress, neuronal injury, hemostasis, and endothelial dysfunction. Evolving technologies have provided high throughput approaches to investigate potential gene and protein signatures, and methods to measure newly discovered markers of cell death and immune responses. Prior to defining the clinical utility of stroke biomarkers, it is critical to understand the inherent limitations of a biomarker-based approach and define its potential value for providing adjunctive diagnostic and prognostic information. The identification and validation of a clinically relevant biomarker, or panel of markers, of stroke will ultimately require incorporation of both stringent research design and assessment in the clinical context in which the marker will be used.
D-dimer is a breakdown product of fibrin mesh after factor XIII stabilization. Previously, many authors have demonstrated a relationship between D-dimer level and stroke progression or type. This study aimed to investigate the relationship between D-dimer level and stroke volume.
Between January 2008 and December 2009, we analyzed the D-dimer levels of 59 acute ischemic stroke patients in our neurosurgical department both upon admission and after seven days of initial treatment. Each patient's National Institute of Health Stroke Scale score, modified Rankin Scales score, Glasgow outcome score, and infarction volume were also evaluated.
Mean D-dimer level at admission was 626.6 µg/L (range, 77-4,752 µg/L) and the mean level measured after seven days of treatment was 238.3 µg/L (range, 50-924 µg/L). Mean D-dimer level at admission was 215.3 µg/L in patients with focal infarctions, 385.7 µg/L in patients with multiple embolic infarctions, 566.2 µg/L in those with 1-19 cc infarctions, 668.8 µg/L in 20-49 cc infarctions, 702.5 µg/L in 50-199 cc infarctions, and 844.0 µg/L in >200 cc infarctions (p=0.044). On the 7th day of treatment, the D-dimer levels had fallen to 201.0 µg/L, 293.2 µg/L, 272.0 µg/L, 232.8 µg/L, 336.6 µg/L, and 180.0 µg/L, respectively (p=0.530).
Our study shows that D-dimer level has the positive correlation with infarction volume and can be use to predict infarction-volume.
We have previously shown that platelet factor 4 (PF4), a platelet-specific CXC chemokine, can directly and specifically inhibit human megakaryocyte colony formation. We therefore hypothesized that PF4 might function as a negative autocrine regulator of megakaryocytopoiesis. Herein we present additional studies characterizing the inhibitory effect of CXC chemokines on human megakaryocyte development. We first corroborated our initial studies by showing that recombinant human (rH) PF4, like the native protein, inhibited megakaryocytopoiesis. We then examined the inhibitory properties of other CXC family members. Neutrophil activating peptide-2 (NAP-2), a naturally occurring N-terminally cleaved beta TG peptide, was found to inhibit megakaryocytopoiesis with two to three orders of magnitude greater potency than PF4. Structure function studies showed that an N-terminal mutation, which eliminated NAP-22s neutrophil activating properties (NAP-2E2-->A), also abrogated its ability to inhibit megakaryocyte development. Further investigations of this type demonstrated that a chimeric PF4 protein (AELR/PF4) in which PF42s N- terminus was replaced with the first four amino acids of NAP-2 was also a potent inhibitor of megakaryocytopoiesis. Interleukin (IL)-8, another CXC chemokine, and three CC chemokines (macrophage inhibitory protein-1 alpha [MIP-1 alpha], MIP-1 beta, and C10) also specifically inhibited megakaryocyte colony formation at NAP-2 equivalent doses. CXC and CC chemokine inhibition was additive suggesting that the effects might be mediated through a common pathway. The inhibitory effects of NAP-2 and MIP-1 alpha could not be overcome by adding physiologically relevant amounts of recombinant human megakaryocyte growth and development factor (MGDR) (50 ng/mL) to the cultures. Using Northern blot and reverse transcriptase-polymerase chain reaction (RT-PCR) based analyses, we documented mRNA expression of IL-8 receptor isoforms alpha and beta in total platelet RNA and in normal human megakaryocytes, respectively. Based on these results, we hypothesize that chemokines play a physiologic role in regulating megakaryocytopoiesis. Because chemokines are elaborated by ancillary marrow cells, both autocrine and paracrine growth control is suggested, the effects of which might be exerted, in part, through alpha and beta IL-8 receptors.
The recognition of molecular marker events leading to hemostatic and thrombotic disorders and technologic advances in molecular biology and immunology has added a new dimension in the diagnosis of bleeding and thrombotic disorders. Pathophysiologic activation of coagulation, fibrinolysis, kallikrein-kinin system, vascu— lar stress, and intercellular interactions result in the generation of cell/process specific markers of a pathophysiologic event. It has been two decades since the concept of molecular markers was first introduced in the diagnosis of hemostatic and thrombotic disorders. However, due to cost/technologic limitations and lack of understanding of this field at various levels its usage in clinical laboratory diagnosis was rather limited. With the advent of such analytical techniques such as enzyme-linked immunosorbent assays (ELISA) a disease specific molecular profiling can be readily accomplished. Subclinical activation of platelets, endothelial distress, and aberrations of the protease network can be readily diagnosed by utilizing specific assays. The concept of hypercoagulable state is now validated utilizing such markers of hemostatic activation such as platelet factor 4, thromboxane B2, fibrinopeptide A and plasminogen activator inhibitor. Cardiovascular disease risk and blood vascular disorders can be diagnosed utilizing these markers. The monitoring of antithrombotic drugs that do not produce any anticoagulant effects on blood can also be readily accomplished by using some of these lanalytes. Using specific monoclonal antibodies, various diagnostic profiles for such disorders as thrombotic stroke, disseminated intravascular coagulation, primary fibrinolysis, hemodynamic disorders, and diseases of vascular origin can be investigated. Since the introduction of this concept some 50 additional markers have been introduced. The recognition of tissue factor pathway inhibitor (TFPI) has introduced a new concept in the understanding of the plasmatic and vascular interactions. Tissue factor and its inhibitor can now be measured at fmol amounts in plasma and body fluids. Specific antibodies to these markers can also be utilized in immunocytometric and flow cytometric analysis and will provide valuable diagnostic information. High through-put instruments and cost/technologies compliance methodologies are available to provide affordable laboratory approaches in the new era of cost constraint diagnostic medicine. However, a major deficit in the educational programs still exists and warrants the development of these programs in medical and allied health curriculums. Key Words: Molecular markers—Hypercoagulable state—Enzyme-linked immunosorbent assay—Tissue factor pathway inhibitor— Tissue factor.
Platelet factor 4 is a low molecular weight protein contained in the storage granules of platelets and released during aggregation with a variety of aggregating agents. In vitro, it is a potent antiheparin. This property has been used for a rapid, simple purification procedure using affinity chromatography on heparin epsilon-aminocaproic aced Sepharose. Supernatants collected from outdated platelet concentrates, or platelet extracts prepared from washed, outdate platlets themselves, are first precipitated with 50% ammonium sulfate. The supernatant is dialyzed and applied to the affinity column. Contaminating proteins are washed from the column with 0.5 M NaCl in 0.005 M sodium barbital buffer, pH 7.4 and the column is then eluted with a gradient of 0.5 to 3.0 M NaCl in 0.005 M sodium barbital buffer, pH 7.4. When prepared from platelet extracts, a single protein peak with high platelet factor 4 activity is eluted at 0.9 to 1.0 M NaCl. The peak fractions demonstrate a single band on Na dodecyl-SO4-polyacrylamide gel electrophoresis. The molecular weight as determined by Na dodecyl-SO4 gel electrophoresis was 11,600 +/- 330, and was 40,000 by gel filtration.
Methods are described for the purification of a heparin-neutralizing protein from human platelets. The protein, obtained by conventional or affinity chromatographic techniques, is homogeneous by disc and sodium dodecyl sulfate gel electrophoresis, immunoelectrophoresis, and gel electrofocusing and can be obtained in a final yield of 75%. The protein has a subunit molecular weight of 9600, an isoelectric point at pH 7.6, and 18% basic and 22% acidic amino acid residues. The purified heparin-neutralizing protein forms dissociable complexes with heparin as measured by electrophoretic and Millipore filtration techniques employing [3H]heparin. The ability of a series of sulfated glycosaminoglycans to displace [3H]heparin from the binding protein was compared. The mole ratios required were: heparin less than heparan sulfate less than dermatan sulfate less than chondroitin 6-sulfate less than chondroitin 4-sulfate. Although the degree of sulfation of the aminoglycans correlated with the ability to displace [3H]heparin, the conformation fo the carboxyl group of the uronic acid and the location of the sulfate groups on the amino sugar also influenced the affinity for the protein. Evidence is also presented that binding to aminoglycans occurs via ionic interactions between lysine residues on the protein and negatively charged groups on the aminoglycan. Chemical modification of lysines by guanidination decreased heparin-neutralizing and binding activity, while modification of arginine residues had no effect. Heparin could prevent lysine modification when specifically bound to the heparin-neutralizing protein, but did not prevent lysine modification of other proteins.
Measurement of plasma levels of two secreted platelet proteins (beta-thromboglobulin and platelet factor 4) has been suggested as a means for detecting increased platelet activation in vivo. A crucial question in the measurement is the distinction between in vivo and in vitro secretion of the proteins. One approach to this distinction is the measurement of both proteins in each sample. These proteins are present in platelets in similar amounts and are released in similar quantities, but the plasma levels of beta-thromboglobulin exceed the plasma levels of platelet factor 4. This difference in plasma level is presumably due to more rapid removal of platelet factor 4 from the plasma level, and there is suggestive evidence that the rapid removal of released platelet factor 4 is due to its binding to endothelial cells. It appears that when there is increased release of beta-thromboglobulin and platelet factor 4 in vivo, there is an increase in the ratio of plasma beta-thromboglobulin to plasma platelet factor 4 compared to that found in normal individuals, whereas when in vitro release is responsible for elevated levels, the ratio decreases. Thus measurements of both proteins in each blood sample will allow distinction between in vivo release and artefactual in vitro release.
Fibrinogen degradation, fibrin polymerisation, and the insertion of cross links into fibrin by fibrin stabilising factor lead to the appearance of new antigenic determinants. Antibodies against these antigenic sites may react specifically with the derivatives but not with the parent molecules. We have utilised a monoclonal antibody, which interacts with the cross linked fragment D dimer and related high molecular weight fibrin derivatives, to develop an enzyme immunoassay which measures cross linked fibrin derivatives in plasma and serum using D dimer as standard. Mean concentration in plasma from normal subjects was 75 ng/ml with an upper limit of about 144 ng/ml. Concentrations in patients with pulmonary embolism, deep venous thrombosis, arterial thromboembolism, and disseminated intravascular coagulation were raised in all cases. Confirmation of the specific increase of cross linked fibrin derivatives in patients with disseminated intravascular coagulation was obtained by parallel monitoring of their fibrin degradation products in serum using affinity chromatography and sodium dodecyl sulphate (SDS) polyacrylamide gel electrophoresis. In many patients the plasma concentrations greatly exceeded the serum values of cross linked fibrin degradation products, suggesting that the procedure can measure fibrin derivatives in plasma which are absent from serum.
This study was designed to determine whether venous thrombosis is associated with a characteristic pattern in the plasma concentrations of fibrinopeptides and platelet alpha granule proteins. Patients undergoing elective craniotomy for tumor or vascular abnormality were studied prospectively for venous thrombosis with the 125I-fibrinogen uptake test and with daily measurement of the plasma concentrations of FPA (fibrinopeptide A), TIFPB (thrombin-increasable fibrinopeptide B reflecting Bβ 1-42), and βTG (β-thromboglobulin). Eighteen patients developed venous thrombosis and 14 did not. In the 14 patients who did not develop thrombosis, the mean FPA level was highest on the day after surgery and exceeded the TIFPB level so that the ratio of FPA to TIFPB, which is ≤ 0.5 in normals, was 1.2. During the next 14 days, both FPA and TIFPB levels were elevated, but the FPA/TIFPB ratio was not significantly different from the preoperative value. βTG and PF4 levels showed no clear pattern of change in the postoperative period. In 10 of the patients who developed thrombosis, the time of onset of thrombosis was documented by a change in the leg scan from negative to positive. In these 10 patients, the mean FPA level rose to equal the TIFPB level, producing an FPB/TIFPB ratio of approximately 1.0 for the 4 days preceding the change of the leg scan from negative to positive (p < 0.001). Changes in the βTG and PF4 levels were not statistically significant. We interpret the FPA and TIFPB levels as a distinct pattern that reflects sustained imbalance between thrombin and plasmin proteolysis of fibrinogen in association with the development of venous thrombosis. The finding of such sustained imbalance between FPA and TIFPB levels suggests that thrombosis is associated with impaired plasmin formation and/or action in addition to excessive fibrin formation. The finding that this pattern was evident several days before the leg scan became positive strongly supports efforts to develop a prognostic blood test. The blood tests used in this study showed adequate sensitivity, but low specificity for the detection of asymptomatic thrombosis. For this reason we suggest that use of these tests be confined to investigating the pathophysiology of thrombosis.
We have previously shown that platelet factor 4 (PF4), a platelet-specific CXC chemokine, can directly and specifically inhibit human megakaryocyte colony formation. We therefore hypothesized that PF4 might function as a negative autocrine regulator of megakaryocytopoiesis. Herein we present additional studies characterizing the inhibitory effect of CXC chemokines on human megakaryocyte development. We first corroborated our initial studies by showing that recombinant human (rH) PF4, like the native protein, inhibited megakaryocytopoiesis. We then examined the inhibitory properties of other CXC family members. Neutrophil activating peptide-2 (NAP-2), a naturally occurring N-terminally cleaved beta TG peptide, was found to inhibit megakaryocytopoiesis with two to three orders of magnitude greater potency than PF4. Structure function studies showed that an N-terminal mutation, which eliminated NAP-2's neutrophil activating properties (NAP-2E2-->A), also abrogated its ability to inhibit megakaryocyte development. Further investigations of this type demonstrated that a chimeric PF4 protein (AELR/PF4) in which PF4's N-terminus was replaced with the first four amino acids of NAP-2 was also a potent inhibitor of megakaryocytopoiesis. Interleukin (IL)-8, another CXC chemokine, and three CC chemokines (macrophage inhibitory protein-1 alpha [MIP-1 alpha], MIP-1 beta, and C10) also specifically inhibited megakaryocyte colony formation at NAP-2 equivalent doses. CXC and CC chemokine inhibition was additive suggesting that the effects might be mediated through a common pathway. The inhibitory effects of NAP-2 and MIP-1 alpha could not be overcome by adding physiologically relevant amounts of recombinant human megakaryocyte growth and development factor (MGDR) (50 ng/mL) to the cultures. Using Northern blot and reverse transcriptase-polymerase chain reaction (RT-PCR) based analyses, we documented mRNA expression of IL-8 receptor isoforms alpha and beta in total platelet RNA and in normal human megakaryocytes, respectively. Based on these results, we hypothesize that chemokines play a physiologic role in regulating megakaryocytopoiesis. Because chemokines are elaborated by ancillary marrow cells, both autocrine and paracrine growth control is suggested, the effects of which might be exerted, in part, through alpha and beta IL-8 receptors.
Epifluorescent microscopy was used to monitor the adhesion of platelets and the growth of platelet aggregates on collagen-coated glass tubes perfused with whole blood. The maximum basal length and width of the aggregate size increased linearly with time, growing symmetrically transverse to the direction of flow and asymmetrically in the plane longitudinal to the direction of flow. Aggregates had elliptical bases, with the major axis parallel to the direction of blood flow. These studies provide an experimental approach to studies of the kinetics of platelet interaction with artificial surfaces and give further support to the concept that blood flow has a major effect on the development of platelet thrombi.
Measurement of plasma levels of two secreted platelet proteins (beta- thromboglobulin and platelet factor 4) has been suggested as a means for detecting increased platelet activation in vivo. A crucial question in the measurement is the distinction between in vivo and in vitro secretion of the proteins. One approach to this distinction is the measurement of both proteins in each sample. These proteins are present in platelets in similar amounts and are released in similar quantities, but the plasma levels of beta-thromboglobulin exceed the plasma levels of platelet factor 4. This difference in plasma level is presumably due to more rapid removal of platelet factor 4 from the plasma level, and there is suggestive evidence that the rapid removal of released platelet factor 4 is due to its binding to endothelial cells. It appears that when there is increased release of beta-thromboglobulin and platelet factor 4 in vivo, there is an increase in the ratio of plasma beta-thromboglobulin to plasma platelet factor 4 compared to that found in normal individuals, whereas when in vitro release is responsible for elevated levels, the ratio decreases. Thus measurements of both proteins in each blood sample will allow distinction between in vivo release and artefactual in vitro release.
β-Thromboglobulin (β-TG) is present in human plasma at 30.7 ± 13.7 ng ml−1 (mean ± S.D.), approximately twice the concentration of platelet factor 4 (PF4). Plasma β-TG appears to equilibrate with synovial and amniotic fluids, but the PF4 concentration in these fluids is lower than in plasma. Neither protein passes freely into the cerebrospinal fluid. In each normal subject, the urinary concentration of β-TG is fairly constant at about 0.% of the plasma concentration. A higher percentage of immunologically intact PF4 enters the urine, but the concentration varies widely. β-TG added to the circulation by serum infusion is cleared with a -life of about 100 min., but the clearance of PF4 is so rapid that its -life cannot be estimated. The two proteins are released simultaneously from platelets . , the circulating concentration of PF4 is increased 20- to 30-fold by intravenous injection of 5000 units of mucous heparin, while β-TG levels remain unchanged.
Background andPurpose: TheOxfordshire CommunityStroke Project (OCSP)clinical classification of subtypes ofcerebral infarction (total andpartial anterior circulation infarction, lacunar infarction, and posterior circulation infarction) can beusedtopredict early mortality, functional outcome,andwhether theinfarct was likely duetolarge- or small-vessel occlusion. TheOCSP classification was originally developed andtested byneurologists as partofa community-based studyoffirst-ever stroke, inwhich some caseswere seenafter theacutephase. Weexamined theinterobserver reliability oftheclassification whenusedineveryday clinical practice inpatients seenduring theacutephaseofstroke shortly after admission tothehospital. Methods: Twoclinicians independently assessed consecutive patients admitted tothehospital withan acutestroke andrecorded boththeneurological features andtheir opinion ofthesubtype ofinfarct. Results: Eighty-five patients were assessed. Interobserver agreement fortheclassification was moderate togood(c=0.54; 95%confidence interval, 0.39to0.68). Differences intheassessment ofthecommonly elicited neurological signs explained many ofthedisagreements: interobserver agreement was goodfor some signs (hemiparesis (K=0.77), dysphasia (Kc=0.70)), moderate forsome (hemianopia (JC=0.39)), and poorforothers (sensory loss(Kc=0.15)). Conclusions: Theclassification was simple andpracticable (andcould bewidely usedinroutine clinical practice, randomized controlled trials, andaudit), andinterobserver reliability was satisfactory. (Stroke. 1993;24:1801-1804.)
Three proteins released from platelets were discussed. A significant advance in the study of the platelet-derived growth factor has been made by the development of a radioimmunoassay. Specific radioimmunoassays have been developed for platelet factor 4 and beta thromboglobulin. The primary structure of platelet factor 4 has been determined in three different laboratories. These three proteins appear to be released simultaneously from platelets by thrombin and collagen. Initial applications have been made of the radioimmunoassays for platelet factor 4 and beta thromboglobulin to clinical blood samples. Further definition of the activity and function of the mitogenic factor and application of all three assays appears to have great potential for advancing our understanding of the physiology of platelets in normal individuals and in disease.
The nature of hematologic disorders in different stroke subtypes remains uncertain. The purpose of this study was to clarify the differences in the coagulation and fibrinolytic activities among ischemic stroke subtypes.
We performed sequential measurements of hematologic parameters in 21 patients with acute cardioembolic stroke, 10 patients with atherothrombotic stroke, 23 patients with lacunar stroke, and 20 age-matched controls.
A marked elevation of plasma concentrations of the thrombin-antithrombin III complex and crosslinked D-dimer was observed only in cardioembolic stroke within 48 hours of onset (p less than 0.01), persisting for one month with a gradual decline. In atherothrombotic stroke, however, the level of crosslinked D-dimer was not elevated at the onset, but increased seven days after onset (p less than 0.01). No significant changes in these marker levels were observed in lacunar stroke.
Our findings suggest that the nature of altered coagulation and fibrinolysis are different in various subtypes of ischemic stroke, and that an assessment of these hematologic parameters may be useful for the early classification of these subtypes.
Stroke is a thrombotic process in at least 80% of cases. The acute phase of stroke is characterized by brisk thrombin activity and relatively depressed fibrinolytic activity. The presence of inhibitors of plasminogen activation may play a role in this impairment of fibrinolytic activity. Fibrinolytic activity rises slowly in the subacute phase after a stroke, but the contribution of specific activators and inhibitors during this time has not been delineated. These findings have important implications for the treatment of acute stroke.An important question remains as to whether all these changes are secondary to the stroke, or whether preexisting abnormalities of fibrinolysis contribute to the occurrence of a stroke. Large prospective epidemiologic studies using current techniques are necessary to determine whether fibrinolytic abnormalities are risk factors for stroke. [68] If this is so it would provide an important means of identifying patients at high risk for stroke. Further, it might eventually lead to new strategies of stroke prevention via augmentation of the fibrinolytic system.
The hematologic disorders in patients with acute cardioembolic stroke are not fully understood, and no reliable measures are available to identify patients at high risk for recurrent embolism. We analyzed coagulation and fibrinolytic functions in 22 patients with cardiogenic cerebral embolism less than or equal to 24 hours after onset and in 25 age-matched controls. The levels of antithrombin III, protein C, and alpha 2-plasmin inhibitor were significantly lower in the patients than in the controls (p less than 0.001, 0.02, and 0.05, respectively). In contrast, the plasma concentrations of thrombin-antithrombin III complex and crosslinked D-dimer were markedly higher in the patients than in the controls (p less than 0.01 and 0.001, respectively). At the time of admission, the plasma concentrations of thrombin-antithrombin III complex and crosslinked D-dimer in the eight patients at high risk for recurrent embolization (one with prodromal embolism, three with intracardiac thrombi, and four with recurrent embolization) were 2.8 and 3.5 times, respectively, higher than those in the 14 patients without recurrence or thrombus formation. The lowest concentration of crosslinked D-dimer in the eight patients at high risk for recurrent embolization was 600 ng/ml on admission. Our results suggest that patients with acute cardioembolic stroke have various degrees of consumption coagulopathy and that the plasma concentrations of thrombin-antithrombin III complex and crosslinked D-dimer can be useful indicators of those who are prone to recurrent embolization during this stage.
We investigated hemostatic function in patients with cerebral ischemia by evaluating platelet activation, fibrin generation, and fibrinolysis. Plasma beta-thromboglobulin, an index of platelet activation, was significantly increased both acutely (14.9 +/- 9.2 ng/mL; n = 85) and approximately 2 months later (17.3 +/- 10.1 ng/mL; n = 57). Thrombin activity was measured using assays for fibrinopeptide A and fibrin D-dimer. Increased fibrinopeptide A was found in 9 (11.5%) of 78 patients acutely and 6 (10.7%) of 56 at follow-up; fibrin D-dimer levels were significantly increased acutely (166 +/- 188 ng/mL; n = 66) but not at follow-up. Fibrinolytic activity was measured using assays for fibrinopeptide B-beta 1-42 and plasminogen activator inhibitor 1. Fibrinopeptide B-beta 1-42 was significantly reduced acutely (6.3 +/- 2.2 pmol/mL; n = 35) and at follow-up (4.8 +/- 1.5 pmol/mL; n = 21). Plasminogen activator inhibitor 1 was normal acutely (20.1 +/- 12.0 ng/mL; n = 73) but increased at follow-up (27.8 +/- 20.1 ng/mL; n = 45). These results demonstrate that patients with cerebral ischemia have abnormal hemostatic function that is not explained by the acute phase reaction, and that components of the prethrombotic state are present in some of these patients.
We assayed plasma concentrations of fibrinogen, fibrinopeptide A, plasmin-alpha 2 plasmin inhibitor complex, D dimer, and antithrombin III activity in 40 patients with cerebral thrombosis and nine patients with cerebral embolism during the acute (less than 7 days), subacute (7-27 days), and chronic (greater than or equal to 28 days) periods and compared these with 69 controls. In cerebral thrombosis, fibrinogen and fibrinopeptide A levels were elevated significantly in all stages (p less than 0.001), whereas plasmin-alpha 2 plasmin inhibitor complex and D dimer levels were elevated significantly in the subacute and chronic periods. The antithrombin III activity was significantly decreased in the acute stage. The elevation of fibrinogen and plasmin-alpha 2 plasmin inhibitor complex levels in the acute stage was significantly greater in patients with an infarct size greater than 10 mm2 compared to patients with an infarct size less than 10 mm2. We observed similar changes in patients with cerebral embolism. These results suggest that enhanced coagulation exists at all stages and endogenous fibrinolysis is activated in the subacute and chronic periods in a large proportion of patients with cerebral thrombosis and embolism.
More than a dozen primary hematologic disorders have been associated with ischemic stroke. Inherited deficiencies of antithrombin III, protein C, and protein S have been linked with stroke in case reports; optimal screening requires functional as well as antigenic assays. Antiphospholipid antibodies and lupus anticoagulants are the most frequently identified acquired states associated with ischemic stroke. Polycythemia vera, sickle cell anemia, sickle-C disease, and essential thrombocythemia are the major disorders of formed blood elements causing stroke. Special, step-wise screening for occult prothrombotic entities in stroke patients is recommended for young persons with stroke of uncertain cause, for those with prior venous thrombosis, for those with a family history of unusual thrombosis, and for those with no other explanation for recurrent stroke. Acquired, perhaps transient, abnormalities of platelets, coagulation inhibition, and fibrinolysis may contribute importantly to brain ischemia in synergy with other mechanisms, but at present these remain ill-defined. The contribution of prothrombotic diatheses to stroke is probably underrecognized and warrants further investigation.
Platelet basic protein (PBP) was purified from the supernatant of thrombin-stimulated, washed human platelets by ion-exchange, affinity, molecular sieve, and high-performance liquid chromatography (HPLC). The NH2-terminal amino acid sequence was determined by automated Edman degradation, revealing 9 unique residues followed by 10 residues of the established low-affinity platelet factor 4/beta-thromboglobulin (LA-PF4/beta TG) sequence. Among the nine were three basic residues, accounting for the high isoelectric point of PBP. Additional evidence for precursor status includes the immunological cross-reactivity of all three species and the ability of plasmin and trypsin to produce from PBP a species resembling beta TG in charge, hydrophobicity, and size. Tryptic peptide maps of PBP and LA-PF4 obtained by reverse-phase HPLC were very similar, and from each protein, a peptide was isolated which showed the amino acid composition predicted for the COOH-terminal tryptic peptide of beta TG. Normal platelets contained predominantly LA-PF4, with PBP ranging from 10% to 30% of total beta TG antigen. This was true even when fresh platelets were lysed with trichloroacetic acid in order to provide the most complete and rapid inhibition of proteolytic activity. beta TG itself was never detected in this situation or in the release supernatant of stimulated platelets, and only rarely in unprotected lysates. In agreement with earlier results, crude preparations of PBP were mitogenic for 3T3 cells, but highly purified preparations of PBP and LA-PF4 were free of this activity.
Although many drugs have inhibitory effects on platelet function, none of them inhibits all of the mechanisms that may be involved in the various forms of thrombosis. Choice of suitable drugs is hampered by lack of full knowledge concerning the reactions that make the major contributions to the formation of arterial thrombi at sites of repeated vessel wall injury or on atherosclerotic lesions. Drugs such as aspirin that inhibit the arachidonate pathway in platelets can only be expected to be effective against thromboembolic events in which the generation of thromboxane A2 plays a major part. If thrombin and fibrin formation are dominant, oral anticoagulant agents or heparin should be beneficial; thus, experimental evidence indicates that with repeated vessel wall injury, the formation of platelet fibrin thrombi on the vessel wall is probably influenced more by inhibitors of thrombin generation than by the subendothelial constituents such as collagen. Agents like prostacyclin that raise platelet cyclic adenosine monophosphate (AMP) levels in platelets by stimulating adenylate cyclase are potent inhibitors of the reaction of platelets to all aggregating and release-inducing stimuli, but these agents are not suitable for long-term administration. The effect of dipyridamole on platelet cyclic AMP levels is weak, and this drug may act through other effects on platelets or on other cells. Indeed, several of the drugs that have been tested in clinical trials may exert their effects through unrecognized mechanisms. Many combinations of drugs have been used to affect platelets or platelets and coagulation. This practice has been based on the theory that because several mechanisms may be involved in thrombus formation, combinations of drugs that inhibit different mechanisms may be beneficial.
To assess the time course of thrombosis and fibrinolysis after acute stroke, we measured concentrations of fibrinopeptide A (FpA), B-beta 1-42 peptide (B-beta 1-42), B-beta 15-42 peptide (B-beta 15-42), and crosslinked D-dimer (XDP) in 31 patients at varying times following acute ischemic stroke and in 13 neurologically stable patients with chronic strokes. FpA levels were markedly elevated during the first week after stroke and declined slowly during the first month. Mean FpA levels were not significantly elevated in chronic stroke patients. Mean XDP levels were slightly elevated during the first week and increased during the next 2 weeks after stroke. B-beta 1-42 and B-beta 15-42 levels were not elevated at any time following acute stroke. Our data suggest that fibrin formation greatly exceeds endogenous fibrinolysis during the acute phase of ischemic stroke. Endogenous fibrinolysis develops slowly following stroke. Prolonged elevation of FpA concentration suggests that thrombin activity and fibrin formation continue for up to 4 weeks in some patients with ischemic stroke.
To evaluate the clinical significance of hemostatic abnormalities in acute stroke, we studied coagulation and platelet function in 70 patients with recent cerebral infarction or hemorrhage and in 45 age-matched controls. Higher levels of one-stage factor VIII coagulant activity, fibrinopeptide A (FPA), and beta-thromboglobulin were associated with the occurrence of stroke. All hemostatic test results were remarkably similar in patients with ischemic and hemorrhagic stroke. FPA levels and size of the lesion on CT were the only variables independently predicting mortality in a multivariate regression analysis. Our findings demonstrate that hypercoagulability is an important prognostic factor in stroke and lend support to clinical trials of drugs interfering with the coagulation system in the early phase of cerebral ischemia.
It remains uncertain whether platelet activation in ischemic stroke is contributory or secondary to brain ischemia. The efficacy of aspirin (ASA) in stroke prevention suggests that platelet activation contributes to the occurrence of stroke. On the other hand, platelet activation may be simply a generalized consequence of cerebral ischemic damage. To examine this issue, plasma levels of the platelet specific proteins beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4) were measured in fifty-eight patients with various defined types of acute ischemic strokes. beta-TG was a broader indicator of platelet activation than PF4. Compared with an age-matched control group, thromboembolic and cardioembolic stroke patients had significantly elevated beta-TG levels (p less than 0.001). Also, beta-TG levels in these stroke categories were significantly higher in samples drawn within the first week after the event than in those drawn later (p less than 0.001). In contrast, beta-TG levels in lacunar stroke patients and in most TIA patients were normal. beta-TG levels did not correlate with the volume of cerebral infarction as measured by planimetry from CT scans. Moreover, beta-TG levels in patients on chronic ASA therapy at the time of stroke did not differ from those in patients of the same diagnostic categories not taking aspirin. These data indicate that platelet activation may be important in some, but not all, subtypes of ischemic stroke and that platelet activation can occur in stroke even though the platelet cyclooxygenase pathway is suppressed.
The plasma concentrations of protein C, an anticoagulant protein, and fibrinopeptide A were measured in 37 patients with acute hemispheric stroke and in age-matched controls with nonvascular neurologic diseases. In 11 stroke patients who died within 15 days after the onset (nonsurvivors) protein C antigen concentration on admission was lower than in the control group (p less than 0.005), with a mean value of 63% of the concentrations found in the 26 survivors (p less than 0.001). The difference in protein C concentrations was not associated with different prothrombin time ratios and serum albumin concentration in survivors and nonsurvivors of stroke and was independent of the size of the cerebral lesion. Increased fibrinopeptide A concentration on admission was found in all stroke patients (p less than 0.001), but it was higher in nonsurvivors than in survivors (p less than 0.01), suggesting that lower protein C concentrations in nonsurvivors might be due to increased thrombin-dependent protein C activation. In survivors, protein C concentration was slightly but significantly higher than in controls (p less than 0.05) and was unchanged 2 months after stroke, a time when fibrinopeptide A concentrations had returned to normal. These results show that protein C is involved in the hemostatic derangement caused by stroke and provide a rationale for clinical trials evaluating the therapeutic supplementation with protein C of patients with acute ischemic stroke.
Platelet factor 4 is a small protein (Mr 7756) from the alpha-granules of blood platelets which binds strongly to and neutralizes the anticoagulant properties of heparin. From an analysis of X-ray crystallographic data a model for the binding of platelet factor 4 to heparin is proposed.
Platelet antiheparin activity or platelet factor 4 (PF4) was purified from material released by collagen from washed pig platelets. After zinc sulfate precipitation and elution with sodium chloride, crude PF4 was further purified by DEAE-cellulose (DEAE-C) chromatography. The maximal antiheparin activity of 1 mg. purified PF4 corresponded to that of 2.1 mg. protamine sulfate. Purified PF4 was destroyed by proteolytic enzymes but was stable at 100 °C. for 10 minutes. The molecular weight of purified PF4 estimated by Sephadex filtration was found to be about 21,000. The purified material migrated to anode at pH 7.0 on microelectrophoresis. On a Sephadex G-150 column at pH 8.0, 35S-heparin eluted later than purified PF4. When PF4 and 35S-heparin were allowed to react before application to the column, the radioactivity eluted close to the void volume. These experiments suggested formation of a complex of heparin with PF4 and this was confirmed by microelectrophoresis. An immunodiffusion test using antiserum to purified PF4, produced in rabbits, indicated that most PF4 preparations had 2 antigens, one of which was related to antiheparin activity. PF4 from pig and human platelets did not cross-react in the immunodiffusion test. Heparin inhibited interaction of PF4 with antiserum. PF4 neither enhanced polymerization of fibrin nor neutralized the anticlotting activity of fibrinogen degradation products.
Epifluorescent microscopy was used to monitor the adhesion of platelets and the growth of platelet aggregates on collagen-coated glass tubes perfused with whole blood. The maximum basal length and width of the aggregate size increased linearly with time, growing symmetrically transverse to the direction of flow and asymmetrically in the plane longitudinal to the direction of flow. Aggregates had elliptical bases, with the major axis parallel to the direction of blood flow. These studies provide an experimental approach to studies of the kinetics of platelet interaction with artificial surfaces and give further support to the concept that blood flow has a major effect on the development of platelet thrombi.
The purpose of this study was to clarify differences in coagulation and fibrinolytic activation between the various subtypes and phases of ischaemic stroke. Haemostatic activation markers were measured in 52 patients with cardioembolic stroke, 32 with atherothrombotic stroke and 54 with lacunar stroke and compared with 23 age-matched controls. Data were obtained in the acute (< or = 7 days after onset), subacute (8-28 days) and chronic (> or = 29 days) phases of stroke. In patients with cardioembolic stroke, D-dimer and alpha 2-antiplasmin-plasmin complex levels were higher during the acute and subacute phases, while thrombin-antithrombin III complex levels were higher during the acute phase than in patients with lacunar stroke and controls. In cardioembolic stroke, fibrinopeptide A was increased during the acute and subacute phases, thrombin-antithrombin III complexes were higher during the subacute phase and D-dimer levels were higher during the chronic phase. Protein C activity was lower during the acute phase than in atherothrombotic stroke, lacunar stroke and controls. Protein C antigen was lower during the acute phase than in lacunar stroke and controls and during the chronic phase than in lacunar stroke. In contrast, only D-dimer levels were higher in atherothrombotic stroke patients than controls during the acute and chronic phases and no significant alterations in these markers were observed in the patients with lacunar stroke. These findings suggest that measurement of molecular markers of coagulation and fibrinolysis may be useful for detecting intracardiac thrombin and plasmin generation in patients with cardioembolic stroke.
Hematologic disorders that induce a thrombotic tendency contribute to overall ischemic stroke risk and may directly cause cerebral ischemia in patients without other risk factors. These disorders include platelet dysfunction, prothrombotic coagulopathies, defective fibrinolysis, abnormal red blood cell-vessel wall interactions, and antiphospholipid antibody syndromes. Multiple mechanisms promoting ischemia may underlie specific hematologic abnormalities. Improved markers for activation of platelets, coagulation and fibrinolysis are now being used to correlate prothrombotic mechanisms with ischemic pathology and, thus, to make therapeutic approaches more precise. Nevertheless, finding the ideal balance between preventing cerebral ischemia and incurring hemorrhagic toxicity remains difficult.
The Oxfordshire Community Stroke Project (OCSP) clinical classification of subtypes of cerebral infarction (total and partial anterior circulation infarction, lacunar infarction, and posterior circulation infarction) can be used to predict early mortality, functional outcome, and whether the infarct was likely due to large- or small-vessel occlusion. The OCSP classification was originally developed and tested by neurologists as part of a community-based study of first-ever stroke, in which some cases were seen after the acute phase. We examined the interobserver reliability of the classification when used in everyday clinical practice in patients seen during the acute phase of stroke shortly after admission to the hospital.
Two clinicians independently assessed consecutive patients admitted to the hospital with an acute stroke and recorded both the neurological features and their opinion of the subtype of infarct.
Eighty-five patients were assessed. Interobserver agreement for the classification was moderate to good (kappa = 0.54; 95% confidence interval, 0.39 to 0.68). Differences in the assessment of the commonly elicited neurological signs explained many of the disagreements: interobserver agreement was good for some signs (hemiparesis [kappa = 0.77], dysphasia [kappa = 0.70]), moderate for some (hemianopia [kappa = 0.39]), and poor for others (sensory loss [kappa = 0.15]).
The classification was simple and practicable (and could be widely used in routine clinical practice, randomized controlled trials, and audit), and interobserver reliability was satisfactory.
Hemostatic markers can identify activation of the coagulation system in stroke patients. We evaluated whether the levels of these markers at the time of stroke are correlated with stroke severity, type, or mortality.
We measured fibrinopeptide A, cross-linked D-dimer, and beta-thromboglobulin in 70 patients within 1 week of stroke. We examined the association between the level of each of these markers and survival. We adjusted for the possible confounding effect of age, stroke type, or stroke severity using a multivariate Cox proportional hazards model.
The median follow-up was 1.22 years. Fourteen patients died during follow-up. Univariate survival analysis identified age (hazard ratio, 1.06; 95% confidence interval [CI], 1.00 to 1.12), stroke type (hazard ratio, 4.44; 95% CI, 1.29 to 15.23), initial Toronto Stroke Scale score (hazard ratio, 5.05; 95% CI, 2.08 to 12.27), cross-linked D-dimer (hazard ratio, 6.43; 95% CI, 2.83 to 14.62), fibrinopeptide A (hazard ratio, 2.14; 95% CI, 1.26 to 3.63), and beta-thromboglobulin (hazard ratio, 7.63; 95% CI, 2.22 to 26.28) as significantly associated with mortality. In a multivariate model, initial stroke severity and each of the hemostatic markers were independently associated with subsequent mortality.
Elevated hemostatic markers after acute ischemic stroke identify patients with increased risk for mortality. This association appears to be independent of stroke severity or stroke type.
Cardioembolic cerebral infarction is a subtype of stroke with a high mortality. The purpose of this study was to determine predictors of in-hospital mortality in 231 consecutive patients with cardioembolic stroke by means of a multivariate analysis. Three predictive models were constructed. A first model was based on demographic, anamnestic and clinical variables collected at the bedside examination (total 8 variables). A second model was based on clinical and neuroimaging variables (total 10 variables). A third model was based on the aforementioned clinical and neuroimaging variables and the presence of early recurrent embolism (total 11 variables). Deteriorated level of consciousness, limb weakness, presence of congestive heart failure, male gender, and age appeared to be independent prognostic factors of in-hospital mortality in the predictive model based on clinical variables and in the predictive model based on clinical and neuroimaging variables. In addition to these variables, early recurrent embolization was selected in the third predictive model. In the first two models, setting a cut-off point of 0.50 for predicting vital status at hospital discharge resulted in a sensitivity of 60%, a specificity of 89% and a total correct classification of 81%. The corresponding values of the third model were 62, 89 and 81%, respectively. These data may help clinicians to establish an early prognosis of this stroke subtype more accurately as well as to allocate patients with cardioembolic stroke in clinical trials correctly.
Different coagulation abnormalities according to stroke subtypes have been reported. We have assessed the clinical utility of D-dimer, a product of fibrin degradation, in the early diagnosis of stroke subtypes.
Patients hospitalized after an acute ischemic cerebrovascular event underwent D-dimer assay (STA Liatest D-Dimer) (reference level, <0.50 micro g/mL) on days 1, 6 +/- 1, and 12 +/- 1 and were studied to identify stroke subtypes.
We included 126 patients (mean age, 75.5 years) and 63 age-matched control subjects. Stroke subtypes were cardioembolic in 34 patients (27%), atherothrombotic in 34 (27%), lacunar in 31 (25%), and unknown in 27 (21%). At all 3 measurements, D-dimer levels were significantly higher in the cardioembolic group (mean +/- SEM, 2.96 +/- 0.51, 2.58 +/- 0.40, and 3.79 +/- 0.30 micro g/mL, respectively) than in the atherothrombotic (1.34 +/- 0.21, 1.53 +/- 0.26, and 2.91 +/- 0.23 micro g/mL, respectively) (P<.05) and lacunar (0.67 +/- 0.08, 0.72 +/- 0.15, and 0.64 +/- 0.06 micro g/mL, respectively) groups (P<.01). The difference was also significant between the latter 2 groups (P<.01). We found no difference between the lacunar group and controls (0.53 +/- 0.14 micro g/mL). According to day 1 measurements, the optimal cutoff point for predicting cardioembolic stroke was 2.00 micro g/mL, resulting in a specificity of 93.2% and in a sensitivity of 59.3%. For predicting lacunar stroke, the cutoff point was 0.54 micro g/mL, with a specificity of 96.2% and a sensitivity of 61.3%.
The increasing use of the D-dimer assay in clinical practice could be extended to patients presenting with acute cerebrovascular ischemic events to help predict stroke subtype.
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