The combination of laser Doppler perfusion imaging and photoplethysmography is useful in the characterization of scleroderma and primary Raynaud's phenomenon

Deep learning classification of systemic sclerosis from multi-site photoplethysmography signals

Introduction: A pilot study assessing a novel approach to identify patients with Systemic Sclerosis (SSc) using deep learning analysis of multi-site photoplethysmography (PPG) waveforms ("DL-PPG"). Methods: PPG recordings having baseline, unilateral arm pressure cuff occlusion and reactive hyperaemia flush phases from 6 body sites were studied in 51 Controls and 20 SSc patients. RGB scalogram images were obtained from the PPG, using the continuous wavelet transform (CWT). 2 different pre-trained convolutional neural networks (CNNs, namely, GoogLeNet and EfficientNetB0) were trained to classify the SSc and Control groups, evaluating their performance using 10-fold stratified cross validation (CV). Their classification performance (i.e., accuracy, sensitivity, and specificity, with 95% confidence intervals) was also compared to traditional machine learning (ML), i.e., Linear Discriminant Analysis (LDA) and K-Nearest Neighbour (KNN). Results: On a participant basis DL-PPG accuracy, sensitivity and specificity for GoogLeNet were 83.1 (72.3-90.9), 75.0 (50.9-91.3) and 86.3 (73.7-94.3)% respectively, and for EfficientNetB0 were 87.3 (77.2-94.0), 80.0 (56.3-94.3) and 90.1 (78.6-96.7)%. The corresponding results for ML classification using LDA were 66.2 (53.9-77.0), 65.0 (40.8-84.6) and 66.7 (52.1-79.2)% respectively, and for KNN were 76.1 (64.5-85.4), 40.0 (19.1-63.9), and 90.2 (78.6-96.7)% respectively. Discussion: This study shows the potential of DL-PPG classification using CNNs to detect SSc. EfficientNetB0 gave an overall improved performance compared to GoogLeNet, with both CNNs performing better than the traditional ML methods tested. Our automatic AI approach, using transfer learning, could offer significant benefits for SSc diagnostics in a variety of clinical settings where low-cost portable and easy-to-use diagnostics can be beneficial.

Domain reporting in systemic sclerosis-related Raynaud's phenomenon: An OMERACT scoping review

BACKGROUND

Raynaud's phenomenon (RP) is a cardinal feature of SSc and is associated with significant disease-related morbidity that impacts on quality of life. The assessment of SSc-RP is challenging. The aim of this scoping review was to evaluate the outcome domains studied and outcome measures used in clinical studies of SSc-RP.

METHODS

Embase, MEDLINE, and the Cochrane Central Register of Controlled Trials were used to identify randomized control trials (RCTs), quasi-randomized studies, case-control studies, prospective and retrospective cohort studies, case series, and cross-sectional studies of adult participants with SSc-associated RP, written in English. A minimum of 25 participants for studies of imaging modalities and 40 participants for questionnaire-based studies was required for inclusion. Basic laboratory and genetic studies were excluded. No limitations were imposed based on intervention, comparator, or study setting. Study characteristics and primary and secondary target domains in each study were recorded.

RESULTS

58 studies (24 randomized clinical trials) were included in the final analysis. The commonest domains captured were severity of attacks (n=35), frequency of attacks (n=28), and duration of attacks (n=19). Objective assessments of digital perfusion were also commonly used in studies of SSc-RP.

CONCLUSION

The outcome domains and the associated outcomes used to assess the impact of SSc-RP in research studies are broad and have varied across studies. The results of this study will inform the OMERACT Vascular Disease in Systemic Sclerosis Working Group to establish a core set of disease domains encompassing the impact of RP in SSc.

Comparison of different forms of Raynaud's phenomenon by LASCA proximal-distal gradient perfusion

OBJECTIVE

To evaluate finger proximal-distal gradient (PDG) perfusion in subjects with primary Raynaud's phenomenon (PRP), then making comparisons with systemic sclerosis (SSc) patients and healthy controls (HC).

METHODS

Consecutive adult PRP subjects were enrolled, along with an equal number of SSc and HC. Peripheral blood perfusion of the hands was assessed by laser speckle contrast analysis (LASCA). PDG was then calculated applying a generalizable formula independent of both intra- and inter-personal factors. Non-specific anti-nuclear autoantibody (ANA) isolated positivity was assessed.

RESULTS

Fifty PRP patients (88 % female, mean age 45 ± 17.9 years) were enrolled, along with 50 SSc patients and 50 HC. After adjusting mean PDG results for age and sex, no significant differences emerged between PRP and SSc (1.80 ± 0.43 vs 1.76 ± 0.53; p = 0.294). Conversely, PRP values were significantly reduced when compared to HC (2.72 ± 0.37; p < 0.001). Among PRP subjects, no significant differences were found regarding isolated ANA positivity (1.86 ± 0.44 vs 1.74 ± 0.44; p = 0.42).

CONCLUSION

PRP and SSc seems to share the same basal PDG perfusion impairment assessed by LASCA. Isolated ANA positivity, in the absence of clinical and capillaroscopic suspicion for secondary causes, should not be considered an exclusion criterion for PRP classification.

Correlation between Microvascular Damage and Internal Organ Involvement in Scleroderma: Focus on Lung Damage and Endothelial Dysfunction

BACKGROUND

Systemic sclerosis (SSc) is an incurable connective tissue disease characterized by decreased peripheral blood perfusion due to microvascular damage and skin thickening/hardening. The microcirculation deficit is typically secondary to structural vessel damage, which can be assessed morphologically and functionally in a variety of ways, exploiting different technologies.

OBJECTIVE

This paper focuses on reviewing new studies regarding the correlation between microvascular damage, endothelial dysfunction, and internal organ involvement, particularly pulmonary changes in SSc.

METHODS

We critically reviewed the most recent literature on the correlation between blood perfusion and organ involvement.

RESULTS

Many papers have demonstrated the link between structural microcirculatory damage and pulmonary involvement; however, studies that have investigated correlations between microvascular functional impairment and internal organ damage are scarce. Overall, the literature supports the correlation between organ involvement and functional microcirculatory impairment in SSc patients.

CONCLUSIONS

Morphological and functional techniques appear to be emerging biomarkers in SSc, but obviously need further investigation.

Nailfold Microvascular Imaging by Dynamic Optical Coherence Tomography in Systemic Sclerosis: A Case-Controlled Pilot Study

In systemic sclerosis, outcome measures of skin microvasculopathy are needed for both clinical trials and practice. The aim of this study was to determine whether dynamic-optical coherence tomography (D-OCT) is able to provide information on microvasculopathy compared with the current gold standard, nailfold videocapillaroscopy (NVC), in patients with systemic sclerosis. This case-controlled study included (i) 40 patients with systemic sclerosis, classified by NVC pattern in four age- and sex-matched groups (normal/nonspecific, early, active, late); (ii) a fifth group of 10 age- and sex-matched healthy controls. All participants underwent NVC and D-OCT. D-OCT images were compared with the corresponding NVC images. Reliability was assessed. D-OCT images visualized the corresponding NVC patterns. D-OCT microvascular flow density was different across the five NVC pattern groups (P = 0.0114) with a significant trend test (P = 0.0006). Microvascular flow density correlated with the NVC semiquantitative score (r = -0.7, P < 0.0001), number of abnormal shapes/mm (r = ‒0.3, P = 0.0264), and number of capillaries/mm (r = 0.6, P < 0.0001). Reliability was excellent (intraclass correlation coefficient > 0.9). In conclusion, in patients with systemic sclerosis, D-OCT provided qualitative and quantitative information on nailfold microvasculopathy, showing a correlation between microvascular flow density and NVC scores. The development of D-OCT as a standardized imaging technique could provide a quantitative outcome measure in clinical trials and practice.

Application of a novel finger temperature device in the assessment of subjects with Raynaud's phenomenon

INTRODUCTION

Finger skin thermometry is one of the most commonly used methods for evaluating the response of the digital vessels to cold stimulation. The aim of this study was to evaluate the applicability of a novel finger skin temperature device for performing cold-stimulation test (CST) in subjects with primary and secondary Raynaud's phenomenon (RP).

METHODOLOGY

A total of 155 consecutive subjects were studied. They were divided into three groups: 73 patients with primary RP (8 males, 65 females, mean age 38.5 ± 16.2), 42 patients with secondary RP (4 males, 38 females, mean age 49.6 ± 13.1, connected with lupus erythematosus and systemic scleroderma), and 40 healthy controls (5 males, 35 females, mean age 38.8 ± 16.6). Standardized CST consisting of exposure of both hands to water with a temperature of 10℃ for 5 minutes was performed. Changes in skin temperature of both wrists and 2-5 fingers were measured using a novel finger temperature device (Courage & Khazaka). Measurements were made before and 5, 10, 15, 20, 25, and 30 minutes after cold stimulation. The time of recovery for baseline temperature of all fingers below 15 minutes was considered normal.

RESULTS

The CST was normal in 6 (8.2%) of the patients with primary RP, in 7 (16.6%) of the patients with secondary RP, and in 28 (70%) of the healthy control subjects. The time of complete recovery of baseline temperature with respect to the first finger and for all 2-5 fingers in the three groups was as follows: 24.8 and 28.5 minutes (primary RP), 21.7 and 26.8 minutes (secondary RP), and 11.1 and 15.2 minutes (healthy subjects). Furthermore, the microcirculation was seriously disturbed (rewarming time >31 minutes of all 2-5 digits of both hands) in 54.1% (n = 79), 34.5% (n = 29) and 5% (n = 4) in the same study groups.

DISCUSSION

Our results suggested that skin microcirculation is more disturbed in patients with primary RP than in patients with secondary RP. In support of this unexpected finding were the results reported by Ruaro B. et al (2019). They investigated the blood perfusion (BP) by laser speckle contrast analysis (LASCA) at different skin areas of hands and found that it was significantly lower in primary RP than in secondary RP related to systemic sclerosis.

CONCLUSION

The new finger temperature device used could be considered useful for performing cold-stimulation test in patients with Raynaud's phenomenon.

Manifestations of cold sensitivity - a case series

Objectives: To characterise cold sensitivity using a semi-structured interview, physical examination, thermal quantitative sensory testing (QST), and laser speckle contrast analysis (LASCA). Methods: Eight women and four men, ages 22-74, with cold sensitivity were interviewed and examined by an occupational physician. Thermal perception thresholds were established using QST, on the pulp of the index and little finger of the most affected hand. Skin perfusion in the dorsum of the hand was measured using LASCA, at baseline, after two-minute 12°C water immersion, and during rewarming. Results: The physical examination yielded few findings indicative of vascular or neurosensory pathology. One subject (8%) had impaired thermal perception thresholds. LASCA at baseline showed absent proximal-distal perfusion gradients in six subjects (50%), and a dyshomogeneous perfusion pattern in five (42%). Perfusion on a group level was virtually unchanged by cold stress testing (median 52.5 PU; IQR 9.0 before versus 51.3 PU; IQR 27.2 afterwards). Conclusions: Physical examination and thermal QST offered little aid in diagnosing cold sensitivity, which challenges the neurosensory pathophysiological hypothesis. LASCA indicated disturbances in microvascular regulation and could prove a useful tool in future studies on cold sensitivity.

Monitoring the microcirculation in the diagnosis and follow-up of systemic sclerosis patients: Focus on pulmonary and peripheral vascular manifestations

Systemic sclerosis (SSc) is a connective tissue disease, characterized by vascular damage and progressive fibrosis, affecting the skin and internal organs. The vascular changes include functional and structural abnormalities in the microcirculation, which play a central role not only in diagnosis but also in the prognosis and follow-up of systemic sclerosis patients. Nailfold videocapillaroscopy (NVC) is a safe, validated, noninvasive, inexpensive, reliable, and reproducible method that allows for the evaluation of structural changes in scleroderma microangiopathy. However, capillary blood flow/perfusion cannot be measured by NVC under standard conditions and, consequently, must rely on various laser techniques and thermography for the assessment and quantification of cutaneous blood perfusion. Other emerging technologies, such as optical Doppler tomography and spectroscopy, may be used to evaluate the skin flow. This review updates current knowledge on the use of microvascular evaluation techniques in SSc, including complications such as digital ulcers and pulmonary arterial hypertension.

Comparison of mental and physical health between patients with primary and secondary Raynaud's phenomenon Category: Article

OBJECTIVE

To compare anxiety, depression, physical health and quality of life in patients with primary Raynaud's phenomenon (PRP) and patients with secondary Raynaud's phenomenon (SRP).

METHOD

Adult patients with Raynaud's phenomenon (RP) were assessed for the severity of anxiety and depressive symptoms, physical health and quality of life by using the General Anxiety Disorder Scale (GAD-7), the Beck Depression Inventory (BDI), the 12-item Short Form Health Survey: Physical Component Scale (PCS-12), and the Raynaud Specific Quality of Life Questionnaire (RQLQ), respectively. Patients with PRP and SRP were recruited for comparison at a single clinical center in Debrecen, Hungary from September to December 2017.

RESULTS

In total, 60 primary and 41 secondary patients with RP were studied. Gender distribution, family status, employment status and smoking were similar in the two groups. Significantly more patients with SRP had anxiety and depressive symptoms than patients with PRP. Patients with SRP had significantly higher GAD-7 and BDI; and lower overall PCS-12 and RQLQ scores than patients with PRP.

CONCLUSION

Anxiety and depression is more common in patients with SRP than in patients with PRP. Patients with SRP have a lower physical health condition and RP specific quality of life than patients with PRP. Anxiety, depression and quality of life impairments should be taken into account when managing all patients with RP. Further study is needed to assess whether appropriately designed interventions have the potential to reduce the mental and physical health burdens of RP on quality of life (QOL), especially in patients with SRP.

Reactive hyperemia-peripheral arterial tonometry is useful for assessment of not only endothelial function but also stenosis of the digital artery

BACKGROUND

Although reactive hyperemia-peripheral arterial tonometry (RH-PAT) is widely used for assessment of endothelial function, RH index (RHI) cannot be measured in some cases when pulse wave amplitude (PWA) is very low. Decrease in PWA is mainly caused by proper palmar digital artery (PPDA) stenosis. The purpose of this study was to evaluate the relationship between PWA measured by RH-PAT and stenosis of the PPDA measured by digital subtraction angiography and to evaluate the limitation of assessment of endothelial function measured by RHI in patients with PPDA stenosis.

METHODS

We measured baseline PWA in 51 fingers including the first to third fingers of both hands in 10 patients who had PPDA stenosis and in 66 fingers that were the first fingers of both hands in 33 subjects who had no PPDA stenosis. Severe stenosis was defined as over 75% by lower percent diameter stenosis between two PPDAs in a finger.

RESULTS

PWA was significantly correlated with stenosis of the digital artery (r=-0.55; P<0.0001). A PWV value of 300mV was the optimal cut-off value for severe stenosis (sensitivity, 84.0%; specificity, 88.5%). Log RHI was significantly lower in patients with PPDA stenosis than in subjects without PPDA stenosis (0.33±0.27 versus 0.73±0.27, P=0.007).

CONCLUSIONS

RH-PAT may be useful for assessment of not only endothelial function but also PPDA stenosis. RHI may be underestimated in patients with PPDA stenosis. We should pay attention to low baseline PWA when measuring RHI.

CLINICAL TRIAL REGISTRATION INFORMATION

URL for clinical trial: http://UMIN; registration number for clinical trial: UMIN000003409.

Advances in nailfold capillaroscopic analysis in systemic sclerosis

Systemic sclerosis is an autoimmune connective tissue disease characterized by early and persistent microvascular impairment which leads to functional and organic manifestations, with progressive fibrosis of the skin and internal organs. Morphological and functional assessment of the peripheral microvasculature is a must, not only for diagnosis but also for the prognosis and therapeutical follow-up of systemic sclerosis patients, as reported in recent studies. Nailfold videocapillaroscopy is the validated technique for the study of scleroderma microangiopathy as it is able to detect peripheral microvascular morphology and both classify and score the capillary abnormalities into different microangiopathy patterns ('Early', 'Active' and 'Late'). Indeed, the possibility to early diagnose and follow the microvascular changes and the safety of the technique have made nailfold videocapillaroscopy a mandatory tool for patient evaluation and included its assessment in the new systemic sclerosis classification criteria. Important links between nailfold videocapillaroscopy patterns and systemic sclerosis clinical manifestations have been described.

A non-invasive technique for the evaluation of peripheral circulatory functions in female subjects with Raynaud's phenomenon

Japanese women now account for 43 percent of the labor force. A number of them are involved in construction, agricultural and forestry jobs. The aim of this study was to establish a non-invasive technique for the evaluation of peripheral circulatory functions in women with Raynaud's phenomenon (RP) and introduce a specific method for the assessment of vascular disturbances in females exposed to hand-transmitted vibration. The subjects of this study were 10 women with primary RP, 7 women with progressive systemic sclerosis (PSS) secondary to RP, and 17 females who were included as the control group. The evaluation of peripheral circulatory functions in all subjects was based on the values of finger blood flow (FBF) and finger skin temperature (FST) measured before, during and following a 5-min recovery period after the hand was immersed in cold water (5°C, 1 min). The measured values of FBF and FST of the primary RP group before and after the immersion test were significantly (p<0.01) lower compared to those of the control group. The technique applied in this study could be used as a non-invasive and tolerable technique to determine the digital circulatory functions in female subjects with RP.

Nickel-Related Intestinal Mucositis in IBS-Like Patients: Laser Doppler Perfusion Imaging and Oral Mucosa Patch Test in Use

Nickel (Ni) is often the trigger of irritable bowel syndrome (IBS)-like gastrointestinal disorders: its ingestion may cause allergic contact mucositis, identifiable by means of oral mucosa patch test (omPT). OmPT effectiveness has been proven, but it is still an operator-dependent method. Laser Doppler perfusion imaging (LDPI) was tested to support omPT in Ni allergic contact mucositis diagnosis. Group A: 22 patients with intestinal/systemic symptoms related to the ingestion of Ni-containing foods. Group B: 12 asymptomatic volunteers. Ni-related symptoms and their severity were tested by a questionnaire. All patients underwent Ni omPT with clinical evaluation at baseline (T0), after 30 min (T1), after 2 h (T2), and after 24-48 h (T3). LDPI was performed to evaluate the mean mucosal perfusion at T0, T1, and T2. Statistical analysis was performed by ANOVA test and Bonferroni multiple-comparison test. All 22 Ni-sensitive patients (group A) presented oral mucosa hyperemia and/or edema at T2. Eight out of the same 22 patients presented a local delayed vesicular reaction at T3 (group A1), unlike the remaining 14 out of 22 patients (group A2). All 12 patients belonging to control group B did not show any alteration. The mean mucosal perfusion calculated with LDPI showed an increase in both subgroups A1 and A2. In group B, no significant perfusion variations were observed. LDPI may support omPT for diagnostic purposes in Ni allergic contact mucositis. This also applies to symptomatic Ni-sensitive patients without aphthous stomatitis after 24-48 h from omPT and that could risk to miss the diagnosis.

[Critical limb ischemia in systemic sclerosis]

Vascular complications are common in systemic sclerosis (SSc). Critical limb ischemia leading to gangrene or amputation occurs in more than 10% of these patients and hence is a common emergency. This report highlights the different pathogenetic mechanisms leading to critical ischemic events and provides guidance for the diagnosis and therapy. Apart from SSc-associated vasculopathy and peripheral arterial disease, thromboembolic events and rarely also vasculitis may cause critical limb ischemia. An interdisciplinary approach to the diagnosis and therapy of these lesions is mandatory. Therapy goals are the prevention of further ischemia and, if possible, revascularization as well as optimal pain management.

Raynaud’s syndrome, 2011

Raynaud’s phenomenon is characterized by intense vasospasm of the digital arteries on cold exposure or emotional stress, leading to well-defined colour changes in the skin of the fingers. Behind the clinical manifestations, there is an imbalance between vasoconstrictor and vasodilator factors. It may be primary or secondary to an underlying condition, including autoimmune diseases. Physical examination, nail fold capillaroscopy and immunological tests can differentiate primary forms from secondary ones. The treatment is based on preventing exposure to cold, emotional stress and the administration of certain drugs and, if attacks are present, vasodilators, prostaglandin analogues and anticoagulants may be given. This review focuses on the characteristics of Raynaud’s phenomenon and the available diagnostic and therapeutic options. Orv. Hetil., 2012, 153, 403–409.