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Clot waveforms of individual patients. (a) Patient 1, (b) Patient 2, (c) Patient 3, (d) Patient 4, (e) Patient 5
Citations
... In this analysis, the optical solidification reaction waveform curve (ie, clotting curve) can be visualized using absorbance measurements. [4][5][6][7][8][9] Complex waveform analyses, which can be performed using ACL TOP software, have been used to evaluate the prognoses of patients with disseminated intravascular coagulation (DIC) and hemophilia. [10][11][12][13][14][15][16][17] In patients with APS, LA induces abnormal extension of the APTT, which suggests that the waveform would probably be distorted. ...
Background and Aims
Hemophilia was diagnosed in precedence research of clot waveform analysis (CWA) using the activated partial thromboplastin time (APTT). In patients with antiphospholipid syndrome (APS), lupus anticoagulant (LA) causes an increase in APTT, suggesting that the waveform would probably be distorted. Therefore, we evaluated using clinical samples. CWA may be useful low cost for clinical detection of LA. We assessed the clinical value of CWA for detection of LA and coagulation using clinical blood samples collected from patients with a prolonged APTT.
Methods
We used patient samples inspected between April 2011 and March 2013 in Yamagata University Hospital. CWA was performed using the ACL TOP coagulation analyzer, and the associated software program was used to calculate APTT clotting endpoints. An atypical peak was defined as a derivative plot that did not conform to the normal S‐shaped clot reaction curve.
Results
In total, 162 patients, including 66 men and 96 women, with an average age of 46 years (range: 24‐89 years) were included. We also collected control samples from unmatched healthy donors. All 162 patients were divided according to medication history or condition into the following five groups: heparin (n = 20), warfarin (n = 23), hepatic dysfunction (n = 13), normal (n = 20), and LA‐positive antiphospholipid syndrome (APS; n = 86). Twenty healthy individuals were included as controls.
Eighty patients had an atypical peak. Among all, 78 patients (90.6%) were LA‐positive, and 2 patients (2.5%) were treated with warfarin. The remaining two patients had prothrombin time international normalized ratios (PT‐INR) >4.0 while taking warfarin. Those who were APS LA positive with thrombosis and without thrombosis had split the reaction of clotting time, deceleration/acceleration time (D/A) ratio of 2.36 (1.99,3.24) vs 2.34 (2.04,2.86), respectively.
Conclusion
The significant atypical peak and D/A ratio extension may be explained by the clotting waveforms observed specifically in patients with LA‐positive APS.
Snake venoms have evolved primarily to immobilize and kill prey, and consequently, they contain some of the most potent natural toxins. Part of that armory is a range of hemotoxic components that affect every area of hemostasis, which we have harnessed to great effect in the study and diagnosis of hemostatic disorders. The most widely used are those that affect coagulation, such as thrombin-like enzymes unaffected by heparin and direct thrombin inhibitors, which can help confirm or dispute their presence in plasma. The liquid gold of coagulation activators is Russell's viper venom, since it contains activators of factor X and factor V. It is used in a range of clotting-based assays, such as assessment of factor X and factor V deficiencies, protein C and protein S deficiencies, activated protein C resistance, and probably the most important test for lupus anticoagulants, the dilute Russell's viper venom time. Activators of prothrombin, such as oscutarin C from Coastal Taipan venom and ecarin from saw-scaled viper venom, are employed in prothrombin activity assays and lupus anticoagulant detection, and ecarin has a valuable role in quantitative assays of direct thrombin inhibitors. Snake venoms affecting primary hemostasis include botrocetin from the jararaca, which can be used to assay von Willebrand factor activity, and convulxin from the cascavel, which can be used to detect deficiency of the platelet collagen receptor, glycoprotein VI. This article takes the reader to every area of the diagnostic hemostasis laboratory to appreciate the myriad applications of snake venoms available in diagnostic practice.
Introduction
Activated partial thromboplastin time (PTT) coagulation waveforms produced by optical detection system coagulation analyzers provide additional potentially useful and routinely underutilized information for the evaluation of a patient's coagulation system. We aimed to identify features of PTT coagulation waveforms, available for all PTT assays performed in our hospital laboratories, that may prove useful in directing early investigations in patients with unexplained prolonged PTT.
Methods
We retrospectively reviewed 211 PTT coagulation waveforms from patient testing and categorized them based on the underlying hemostatic abnormality: normal, therapeutic anticoagulation, lupus anticoagulant, congenital factor deficiency, or acquired factor VIII inhibitor. We compared quantitative waveform parameters and the frequency of qualitatively abnormal double‐peaked first derivative waveform curves between these groups.
Results
Partial thromboplastin time and derivative curve maxima and minima differed significantly between acquired factor VIII inhibitors and other diagnostic categories, and the second derivative curve minimum demonstrated the highest area under the receiver operator characteristic curve for identification of acquired factor VIII inhibitors (0.860; maximum accuracy: 79.5% for 2Dmin> −39.3 mAbs/s² [sensitivity 90.5%; specificity 77.2%]). The presence of an abnormal double‐peaked first derivative curve had a sensitivity of 83.3% and specificity of 81.6% for identification of acquired factor VIII inhibitors in cases with PTT >50 seconds.
Conclusion
Partial thromboplastin time coagulation waveform analysis can aid in identification of patients with acquired factor VIII inhibitors and may be of clinical utility in directing early laboratory investigations to identify patients at risk of severe bleeding without prompt intervention.
