Figure 1 - uploaded by Antonella Marcoccia
Content may be subject to copyright.
Normal appearance and density of capillaries in the human nailfold. Notice normal density and regular appearance of the capillaries in the first row.
Source publication
The term "microcirculation" refers to the terminal vascular network of the body, which includes arterioles, capillaries, venules as well as initial lymphatic vessels. Additionally, it insinuates to their unique function in thermoregulation, fluid balance, maintenance of cellular exchange, and metabolism. Disturbances of microvascular function were...
Context in source publication
Context 1
... was promoted as a first line diagnostic tool in Raynaud's phenomenon and in suspected connective tissue diseases, especially systemic sclerosis [12,30,31]. It proofed helpful to differentiate between a normal capillary pattern (see Figure 1), which is easy to learn and reproduce, unspecific morphologic or functional changes, and specific capillaroscopic pattern associated with scleroderma spectrum disorders [12,[32][33][34]. ...
Citations
... In recent years, the crucial importance of microcirculation for limb preservation in both DFS and PAD has been emphasized. There is clear evidence that the microvascular function is altered first in the presence of risk factors associated with atherosclerosis (17). Even at the stage of intermittent claudication, microcirculation plays an important pathophysiological role (18). ...
Background
Globally, diabetes mellitus (DM) and peripheral artery disease (PAD) have an increasing incidence and a high prevalence and are both associated with high morbidity and complication rates, e.g., as chronic non-healing peripheral ulcers. Impaired macro- and microcirculation and peripheral neuropathy lead to an increased risk of foot ulcers and infections. These complications are difficult to treat, have a high risk of becoming chronic and often lead to lower limb amputation. The aim of this planned study was to investigate the potential effects of acupuncture on improving microcirculation in patients with Diabetic Foot Syndrome (DFS) and PAD.
Materials and methods
In 18 patients with chronic non-healing peripheral ulcers and diagnosed DM or PAD, data on 8 microcirculatory parameters were collected simultaneously on intact skin close to the wound margin. Microcirculation was assessed using an O2C device combining laser Doppler shift and white light spectroscopy (LEA Medizintechnik GmbH, Giessen, Germany). Unilateral and bilateral acupuncture was performed on the connecting line between acupuncture points Stomach 14 and Stomach 15.
Results
After unilateral acupuncture (ipsilateral to the wound side), a statistically significant improvement in 7 out of 8 microcirculatory parameters was demonstrated compared to baseline measurements before acupuncture. After bilateral acupuncture, there was an additional improvement and statistical significance in all parameters in both DFS and PAD patients.
Discussion
These results show an improvement in the microcirculation and peripheral blood flow at the edges of the wound. As impaired micro- and macrocirculation is considered to be a critical prognostic factor for the healing of a peripheral lesion, the intervention could have a positive impact on the healing of (chronic) peripheral wounds.
... ON-INVASIVE and quantitative in-vivo assessment of skin features, including the microvasculature, carries significant potential for diagnostics and disease monitoring in a number of pathologies [1,2]. However, the use of non-invasive observations is currently limited by the tools available. ...
Ultra-wideband raster-scan optoacoustic mesoscopy (RSOM) is a novel modality that has demonstrated unprecedented ability to visualize epidermal and dermal structures
in-vivo
. However, an automatic and quantitative analysis of three-dimensional RSOM datasets remains unexplored. In this work we present our framework: Deep Learning RSOM Analysis Pipeline (DeepRAP), to analyze and quantify morphological skin features recorded by RSOM and extract imaging biomarkers for disease characterization. DeepRAP uses a multi-network segmentation strategy based on convolutional neural networks with transfer learning. This strategy enabled the automatic recognition of skin layers and subsequent segmentation of dermal microvasculature with an accuracy equivalent to human assessment. DeepRAP was validated against manual segmentation on 25 psoriasis patients under treatment and our biomarker extraction was shown to characterize disease severity and progression well with a strong correlation to physician evaluation and histology. In a unique validation experiment, we applied DeepRAP in a time series sequence of occlusion-induced hyperemia from 10 healthy volunteers. We observe how the biomarkers decrease and recover during the occlusion and release process, demonstrating accurate performance and reproducibility of DeepRAP. Furthermore, we analyzed a cohort of 75 volunteers and defined a relationship between aging and microvascular features
in-vivo
. More precisely, this study revealed that fine microvascular features in the dermal layer have the strongest correlation to age. The ability of our newly developed framework to enable the rapid study of human skin morphology and microvasculature in-vivo promises to replace biopsy studies, increasing the translational potential of RSOM.
... The PPI results allow visualization of malperfusion. It shows up as a relatively dark part in the BPA map [26]. In addition, the microcirculatory condition can be used to make a prognosis for some diseases. ...
photoplethysmographic imaging (PPI) is a noninva-sive method for assessing local blood flow beneath the skin surface by a video camera. The synchronization detection algorithm based on lock-in amplification (LIA) is a widely used method to obtain PPI. This method can obtain two maps: one is the amplitude map, which represents the strength of the PPG signal, and the other is the pulse-transit-time (PTT) map, which represents the time synchronization of the PPG signal. The latter is usually represented directly in form of a phase map. However, in general, the frequency of PPG signals is time-varying and contains harmonic components, which complicates the application of the algorithm. This article analyzes the relationship between the LIA calculation results and the time delay when the frequency of the signal is time-varying or the signal contains harmonics. Theoretical analysis results show that, when the signal contains harmonic components, the relationship between time delay and phase is approximately linear only when the time delay is not very large or the harmonic components are not very strong. Meanwhile, amplitude appears as a "bell-shaped" function, with its peak value located at the zero time delay. Video data were acquired by the video PPG acquisition system built in our laboratory, and the PPI was calculated by the synchronous detection algorithm using a reference signal generated directly by the Hilbert transform of an actual signal. Experiments show that the proposed method can obtain more stable results than using a constant-frequency reference signal when dealing with time-varying heart rate data. An interesting finding is that, when the reference signal contains harmonic components, PPG distribution features in the amplitude map can be enhanced. Index Terms-Hilbert transform, lock-in amplification (LIA), photoplethysmographic imaging (PPI), synchronous detection.
... Several techniques are currently available to determine tissue perfusion in the lower extremity. Transcutaneous oxygen pressure (TcPo 2 ) measurement is the most commonly used technique for tissue perfusion [1,[3][4][5][6][7][8]. Unfortunately, this technique is time consuming, operator dependent, and the level of high-quality evidence remains low [2,9,10]. ...
Purpose:
Hyperspectral imaging (HSI) is a noninvasive spectroscopy technique for determining superficial tissue oxygenation. The HyperView™ system is a hand-held camera that enables perfusion image acquisition. The evaluation of superficial tissue oxygenation is warranted in the evaluation of patients with peripheral arterial disease. The aim was to determine the reliability of repeated HSI measurements.
Methods:
In this prospective cohort study, HSI was performed on 50 healthy volunteers with a mean age of 26.4 ± 2.5 years, at the lower extremity. Two independent observers performed HSI during two subsequent measurement sessions. Short term test-retest reliability and intra- and inter-observer reliability were determined, and generalizability and decision studies were performed. Transcutaneous oxygen pressure (TcPO2) measurements were also performed.
Results:
The short term test-retest reliability was good for the HSI values determined at the lower extremity, ranging from 0.72 to 0.90. Intra- and inter-observer reliability determined at different days were poor to moderate for both HSI (0.24 to 0.71 and 0.30 to 0.58, respectively) and TcPO2 (0.54 and 0.56, and 0.51 and 0.31, respectively). Reliability can be increased to >0.75 by averaging two measurements on different days.
Conclusion:
This study showed good short term test-retest reliability for HSI measurements, however low intra- and inter-observer reliability was observed for tissue oxygenation measurements with both HSI and TcPO2 performed at separate days in young healthy volunteers. Reliability of HSI can be improved when determined as a mean of two measurements taken on different days.
... Therefore, in our protocol study we decided to evaluate the effectiveness of iloprost in improving the microcirculation of the foot in CLTI patients undergoing BTK procedure [23]. ...
Background: Two-dimensional (2D) perfusion angiography is useful for the evaluation of foot perfusion in patients with critical limb-threatening ischemia (CLTI). Iloprost is a synthetic prostacyclin analogue presenting vasodilating properties. Aim of this study was to demonstrate the utility of 2D perfusion angiography as quantitative method to evaluate iloprost effect on foot circulation. Patients and methods: Between January 2020 and June 2020 25 patients with CLTI underwent below-the-knee (BTK) endovascular revascularization, intra-arterial administration of iloprost, and assessment of foot perfusion by 2D perfusion angiography. Iloprost was administered as an intra-arterial bolus of 3 μg over 1–3 minutes immediately after BTK revascularization. The 2D perfusion angiography was performed in a standardized manner with a 5-F catheter placed into the popliteal artery. A wide region of interest (ROI) was identified to assess the foot perfusion. Time–density curves were calculated by the perfusion software. Changes of the overall time-density curves before and after the administration of iloprost were evaluated. Results: Endovascular revascularization was successful in all cases. The mean reduction of systolic pressure value after iloprost administration was 23.1 mmHg. Eight patients (32%) experienced a minor complication (6 cutaneous rush, 2 symptomatic hypotension >40 mmHg). In 20 patients the time-density curves under ROI increased after the intra-arterial administration of iloprost (+31.6%, range from +4.9% to +78.7%). Five patients had no modification or a slight decrease of foot perfusion after iloprost administration (non-responders patients). Conclusions: Patients undergoing intra-arterial administration of iloprost accounted for a not negligible rate of minor complications. 2D perfusion angiography was valuable as quantitative method to evaluate the iloprost effect on foot circulation. This technique could be useful to classify the patients in responders or non-responders to iloprost therapy.
... The skin is suited for the monitoring of ischaemia as it is readily accessible and skin physiology gives direct indications of underlying local parameters such as metabolic activity and blood and oxygen supply (Löndahl et al., 2011;Houben, Martens and Stehouwer, 2017;Marcoccia et al., 2020). TcPO2 detection was developed in neonatology, ...
NICE NG19 (2015) guides the early identification of neuroischaemia to help prevent diabetes foot complications, but these largely subjective assessments are not standardised. The aim of this doctoral thesis was to explore the concept that new technological devices (DPNCheck® and Medicap) could give a picture that is clearer and closer to that truth of underlying neuroischaemia, than existing NICE NG19 methods (10g monofilament and TBI). To achieve this, a series of cross-sectional observational investigations were undertaken to establish the reliability, validity and clinical effectiveness of the DPNCheck® against the 10g monofilament in the assessment of sensory neuropathy, and the Medicap against the TBI in the assessment of ischaemia, in adults with type 2 diabetes. Experimental Study 1 investigated DPNCheck® reliability in 21 healthy participants, and found ICC (2,1)velocity = 0.97 (95% CI = 0.91- 0.99), and ICC (2,1)amplitude between 0.76 – 0.96 (95% CI = 0.63 – 0.99). Medicap validity was investigated against a TCM400 amongst healthy (Experimental Study 2) and low risk diabetes (Experimental Study 3) participants. The Medicap demonstrated criterion validity, but overestimated TcPO2 by a mean of 24.8 (± 18.4) mmHg. Experimental Study 4 found TBI intrarater reliability ICC (2,2) ranging from 0.79 – 0.99 (SEM = 0.03; 95% CI; 0.68 – 0.99), and interrater reliability with ICC(2,2) between 0.81 – 0.98 (SEM 0.03; 95% CI; 0.65 – 0.99) ; and overall ICC (2,3) =0.96 (95% CI; 0.93 – 0.98). Experimental study 5 investigated the intrarater reliability of the TBI, DPNCheck®, Medicap and 10g monofilament in people with diabetes, and found ICC (3,1)TBI = 0.97 (95% CI = 0.84-0.99), and for ICC(3,1)DPNCheck® velocity and amplitude =0.96 ((95% CI = 0.87-0.99); ICC(3,1) Medicap = 0.66 (95% CI = 0.24 – 0.87), and ICC(3,1) 10g monofilament = 0.38 (95% CI = -0.08 – 0.73). In Experimental Study 6, from 92 participants with diabetes, the DPNCheck® suspected 45 participants of having neuropathy, against 21 by the 10g monofilament which had a false negative rate of 35.2%, a sensitivity of 44.4% (95% CI = 30.9 – 58.8%), specificity of 97.9% (95% CI = 88.9 -99.6%) and k=0.43 (95%C1:0.26 - 0.54; p < 0.001). In Experimental Study 7, both the TBI and Medicap each suspected 10 participants of ischaemia, but did not agree on any cases. Against the TBI, Medicap sensitivity was 0% (95% CI = 0 – 30.9%); specificity 86.6% (95% CI = 77.3- 93.1%), and - 0.12 (p = 0.24). The Medicap demonstrated criterion validity and fair reliability, whilst the DPNCheck® demonstrated and excellent reliability. The DPNCheck® was more effective at assessing sensory neuropathy than the 10g monofilament, whilst the Medicap and the TBI were poorly comparable in the assessment of ischaemia. Findings from these thesis investigations point to a new clinical paradigm for earlier detection of peripheral neuropathy in which the quality and quantity components of neuroischaemia assessment could be combined. The implications for this would be in the detection of neuropathy at the stage where interventions have the potential to change the course of tissue damage and thus prevent diabetes related foot ulceration and amputation.
Einleitung Bei zunehmender Alterung der Bevölkerung kommt es zu einem gehäuften Vorkommen von Majoramputationen als Ultima Ratio bei chronischer Ischämie und/oder Diabetes mellitus. Ein erhöhter Altersdurchschnitt geht mit vermehr-ter Mobilitätseinschränkung, Multimorbidität und erhöhter Pflegebedürftigkeit einher. Das Ziel der Studie besteht darin, den postoperativen Verlauf und das Outcome in Bezug auf Erhaltung der Mobilität, Alltagsbewältigung und Über-leben nach vaskulär-bedingten Majoramputationen zu untersuchen. Material und Methoden Es wurde eine prospektive Single-Center-Registerstudie für Majoramputatio-nen durchgeführt. Der Einschluss der Patienten erfolgte vom 01.07.2020 bis zum 30.06.2021. Einschlusskriterien waren eine Ober- oder Unterschenke-lamputation bei kritischer Extremitätenischämie oder Infektion. Es musste eine Einwilligungsfähigkeit vorliegen. Onkologisch- oder traumabedingte Amputati-onen galten als Ausschlusskriterium. Das Follow-Up der Patienten erfolgte telefonisch mittels Erhebung der körperlichen und psychischen Gesundheit mit Hilfe des SF-12, der Qualität der Prothesenmobilität mittels Houghton-Score, der allgemeinen Alltagsbewältigung mit Hilfe des Barthel-Index und die Abfrage der numerischen Schmerzskala. Die Befragungen wurden anhand des Studienprotokolls auf präoperativ, zwei Wochen nach Amputation, nach absolvierter Rehabilitation, drei und sechs Monate postoperativ festgelegt. Zu-dem erfolgte die Erfassung von Prothesenversorgung und Überleben. Ergebnisse Insgesamt wurden 64 % männliche und 36 % weibliche Patienten mit einem Durchschnittsalter von 68,4 Jahren amputiert. Bei 72 % erfolgte eine Ober-schenkelamputation, bei 28 % eine Unterschenkelamputation. 25 % der er-fassten Patienten verstarben im Beobachtungszeitraum von sechs Monaten. Es zeigten sich im Laufe des Follow-Up signifikante Verbesserungen des Bar-thel-Index (p = 0,001) und der psychischen Gesundheit (p = 0,008) im Ver-gleich zu den präoperativen Werten. Patienten mit einem initial höheren Bar-thel-Index wurden häufiger rehabilitationsfähig (85 vs. 58; p = 0,021) und be-kamen die Möglichkeit einer Prothesenanpassung (85 vs. 70; p = 0,017). Zu-dem zeigte sich ein höherer Ausgangswert für die körperliche Gesundheit als signifikanter Prognosefaktor (33 vs. 25; p = 0,03) für eine erfolgreiche Prothe-senmobilität. Schlussfolgerung In der Nachbeobachtung zeigte sich im Langzeitverlauf eine Verbesserung der Alltagsfähigkeit und der psychischen Gesundheit nach erfolgter Majoramputa-tion. Die Sterblichkeit nach Majoramputationen ist mit 25 % weiterhin hoch. Die Rehabilitations- und Prothesenfähigkeit wird maßgeblich vom Ausgangs-Barthel-Index beeinflusst. Deshalb sollten Majoramputationen, wenn indiziert, zeitnah nach Indikationsstellung erfolgen, um bessere Voraussetzungen zum Erreichen einer Prothesenmobilität zu schaffen.
Objectives: Nailfold video-capillaroscopy (NVC) is an inexpensive method of assessing microcirculation. We reviewed the literature to assess whether changes to the nailfold capillaries exist in patients with cardiovascular disease (CVD).
Methods: We searched PubMed, Scopus and Cochrane Library databases for original research articles relating to the use of noninvasive microvascular assessment in patients with CVD. Methodological quality was assessed with the 'Quality Assessment Tool for Observational Cohort and Cross-sectional Studies.' The results obtained from NVC were analysed qualitatively and compared with other forms of microvascular assessment.
Results: In total 2759 articles were screened, of which 22 studies involving 562 patients (~40% women) with CVD were included. Mean age ranged between 3.7-68.4 years (cases) and 4.0-58.0 years (controls). Reduced capillary density and increased capillary dimensions were seen in patients with pulmonary arterial hypertension (PAH). Among patients with systemic sclerosis, advanced scleroderma patterns can be used to identify patients with or at risk of developing PAH. Functional nailfold changes precede structural changes in patients with hypertension. However, the studies were heterogeneous in the diagnosis of disease and the measurement of nailfold parameters. Most studies did not exclude conditions with altered nailfold features, and only one study performed a power calculation. Furthermore, abnormal nailfold findings are present in patients without systemic disease.
Conclusions: Structural and functional changes to the nailfold are a feature of established CVD and precede the development of PAH. However, heterogeneity in measurement and abnormal findings in healthy participants limit their use in the wider population.
Whole body vibration (WBV) has been suggested as improving skin and blood flow. This study aimed to determine the effect of exposure to WBV on levels of partial transcutaneous oxygen pressure (TcPO2) in the foot of patients with type 2 diabetes (T2D) within the metabolic control goals. A block randomized, open, two-arm, parallel and controlled clinical trial was conducted. Participants recruited from the Center of Comprehensive Care for the Patient with Diabetes were assessed at the National Institute of Rehabilitation, Mexico City. Control group underwent multidisciplinary care for T2D; experimental group, in addition to the comprehensive diabetes care, was exposed to WBV through an exercise program, attending three times a week for a period of 3 months. TcPO2 was measured in the feet of the participants at baseline and after 12 weeks. A sample of 50 volunteers with recently-diagnosed T2D and similar baseline characteristics (demographic, cardiovascular risk, presence of diabetic polyneuropathy, and indicators of glycemic control and TcPO2) was recruited. The experimental group (n=27) showed a mean value of 47.7±6.1 mmHg in TcPO2, significantly higher (p=0.028) than the 44.3±7.5 mmHg of control group (n=23), at the end of intervention. In conclusion, exposure to WBV promoted an increase and a significant 3 mmHg difference in the foot TcPO2 levels between those subjects with T2D that underwent the 12-week exercise program and those not exposed to the treatment.
Objective
Many techniques have been introduced to enable quantification of tissue perfusion in patients with peripheral arterial disease (PAD). Currently, none of these techniques is widely used to analyse real time tissue perfusion changes during endovascular or surgical revascularisation procedures. The aim of this systematic review was to provide an up to date overview of the peri-procedural applicability of currently available techniques, diagnostic accuracy of assessing tissue perfusion and the relationship with clinical outcomes.
Data Sources
MEDLINE, Embase, CINAHL, and the Cochrane Central Register of Controlled Trials.
Review Methods
This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic review and Meta-Analysis (PRISMA) guidelines. Four electronic databases were searched up to 31 12 2020 for eligible articles: MEDLINE, Embase, CINAHL and the Cochrane Central Register of Controlled Trials. Eligible articles describing a perfusion measurement technique, used in a peri-procedural setting before and within 24 hours after the revascularisation procedure, with the aim of determining the effect of intervention in patients with PAD, were assessed for inclusion. The QUADAS-2 tool was used to assess the risk of bias and applicability of the studies.
Results
An overview of 10 techniques found in 26 eligible articles focused on study protocols, research goals, and clinical outcomes is provided. Non-invasive techniques included laser speckle contrast imaging, micro-lightguide spectrophotometry, magnetic resonance imaging perfusion, near infrared spectroscopy, skin perfusion pressure, and plantar thermography. Invasive techniques included two dimensional perfusion angiography, contrast enhanced ultrasound, computed tomography perfusion imaging, and indocyanine green angiography. The results of the 26 eligible studies, which were mostly of poor quality according to QUADAS-2, were without exception, not sufficient to substantiate implementation in daily clinical practice.
Conclusion
This systematic review provides an overview of 10 tissue perfusion assessment techniques for patients with PAD. It seems too early to appoint one of them as a reference standard. The scope of future research in this domain should therefore focus on clinical accuracy, reliability, and validation of the techniques.
