Development of a measuring app for systemic sclerosis-related digital ulceration (SALVE: Scleroderma App for Lesion VErification).

OBJECTIVES: To test the hypothesis that photographs (in addition to self-reported data) can be collected daily by patients with systemic sclerosis (SSc) using a smartphone app designed specifically for digital lesions, and could provide an objective outcome measure for use in clinical trials. METHODS: An app was developed to collect images and patient reported outcome measures (PROMS) including Pain score and the Hand Disability in Systemic Sclerosis-Digital Ulcers (HDISS-DU) questionnaire. Participants photographed their lesion(s) each day for 30 days and uploaded images to a secure repository. Lesions were analysed both manually and automatically, using a machine learning approach. RESULTS: 25 patients with SSc-related digital lesions consented of whom 19 completed the 30-day study, with evaluable data from 27 lesions. Mean (standard deviation [SD]) baseline Pain score was 5.7 (2.4) and HDISS-DU 2.2 (0.9), indicating high lesion and disease-related morbidity. 506 images were used in the analysis (mean number of used images per lesion 18.7, SD 8.3). Mean (SD) manual and automated lesion areas at day 1 were 11.6 (16.0) and 13.9 (16.7) mm2 respectively. Manual area decreased by 0.08mm2 per day (2.4mm2 over 30 days) and automated area by 0.1mm2 (3.0mm2 over 30 days). Average gradients of manual and automated measurements over 30 days correlated strongly (r = 0.81). Manual measurements were on average 40% lower than automated, with wide limits of agreement. CONCLUSION: Even patients with significant hand disability were able to use the app. Automated measurement of finger lesions could be valuable as an outcome measure in clinical trials.

A phase 2 trial investigating the effects of the angiotensin II type 2 receptor agonist C21 in systemic sclerosis-related Raynaud's.

OBJECTIVE: Our main aim was to investigate the effect of a single oral dose of C21, a selective angiotensin II type 2 receptor agonist, on cold-induced vasoconstriction in SSc-related RP. METHODS: This was a phase IIa, randomized, double-blind, cross-over, single-dose, placebo-controlled, single-centre study. Twelve female patients with SSc (median age 58.5 years, median duration of RP 19.0 years) attended on four occasions: screening, treatment visits 1 and 2 (separated by 3-7 days) and follow-up. At the first treatment visit, patients were randomized to receive either a single oral dose of C21 (200 mg) or placebo, then the opposite treatment on the second visit. Forty min after each treatment, each patient underwent a standard hand cold challenge. The primary end point was the area under the curve (AUC) for rewarming for each finger (eight fingers) over 15 min. Secondary end points included the maximum finger temperature after rewarming (MAX). Statistical analyses were performed by multiplicative ANCOVA models. RESULTS: For all eight fingers combined, mean AUC for rewarming was higher after treatment with C21 than after placebo (geometric mean 20 046°C*s vs 19 558°C*s), but not significantly (P = 0.380) and MAX (at 15 min) was also higher (geometric mean 23.5°C vs 22.5°C; P = 0.036). C21 was well tolerated. CONCLUSION: Despite the small trial size, a signal emerged suggesting that even in patients with established SSc, C21 may confer benefit for RP and deserves further investigation. TRIAL REGISTRATION: ClinicalTrials.gov, https://clinicaltrials.gov, NCT04388176.

A deep learning system for quantitative assessment of microvascular abnormalities in nailfold capillary images.

OBJECTIVES: Nailfold capillaroscopy is key to timely diagnosis of SSc, but is often not used in rheumatology clinics because the images are difficult to interpret. We aimed to develop and validate a fully automated image analysis system to fill this gap. METHODS: We mimicked the image interpretation strategies of SSc experts, using deep learning networks to detect each capillary in the distal row of vessels and make morphological measurements. We combined measurements from multiple fingers to give a subject-level probability of SSc.We trained the system using high-resolution images from 111 subjects (group A) and tested on images from subjects not in the training set: 132 imaged at high-resolution (group B); 66 imaged with a low-cost digital microscope (group C). Roughly half of each group had confirmed SSc, and half were healthy controls or had primary RP ('normal'). We also estimated the performance of SSc experts. RESULTS: We compared automated SSc probabilities with the known clinical status of patients (SSc versus 'normal'), generating receiver operating characteristic curves (ROCs). For group B, the area under the ROC (AUC) was 97% (94-99%) [median (90% CI)], with equal sensitivity/specificity 91% (86-95%). For group C, the AUC was 95% (88-99%), with equal sensitivity/specificity 89% (82-95%). SSc expert consensus achieved sensitivity 82% and specificity 73%. CONCLUSION: Fully automated analysis using deep learning can achieve diagnostic performance at least as good as SSc experts, and is sufficiently robust to work with low-cost digital microscope images.

Non-invasive imaging and clinical skin scores in juvenile localised scleroderma.

OBJECTIVES: To evaluate whether in juvenile localised scleroderma (JLS), non-invasive imaging can differentiate affected from non-affected skin and whether imaging correlates with a validated skin score (Localised Scleroderma Cutaneous Assessment Tool, LoSCAT). METHODS: 25 children with JLS were recruited into a prospective study and a single 'target' lesion selected. High frequency ultrasound (HFUS, measuring skin thickness), infrared thermography (IRT, skin temperature), laser Doppler imaging (LDI, skin blood flow) and multispectral imaging (MSI, oxygenation), were performed at four sites: two of affected skin (centre and inner edge of lesion) and two of non-affected skin (one cm from edge of lesion 'outer' and contralateral non-affected side), at 4 visits at 3 monthly intervals. RESULTS: Differences between affected and non-affected skin were detected with all 4 techniques. Compared with non-affected skin, affected skin was thinner (p< 0.001) with higher temperature (p< 0.001-0.006), perfusion (p< 0.001-0.039) and oxygenation (p< 0.001-0.028). Lesion skin activity (LoSCAT) was positively correlated with centre HFUS (r = 0.32; 95% CI [0.02, 0.61]; p= 0.036) and negatively correlated with centre LDI (r=-0.26; 95% CI [-0.49, -0.04]; p= 0.022). Lesion skin damage was positively correlated with centre and inner IRT (r = 0.43; 95% CI [0.19, 0.67]; p< 0.001, r = 0.36, 95% CI [0.12, 0.59]; p= 0.003, respectively) and with centre and inner LDI (r = 0.37; 95% CI [0.05, 0.69]; p= 0.024, r = 0.41; 95% CI [0.08, 0.74]; p= 0.015, respectively). CONCLUSION: Non-invasive imaging can detect differences between affected and non-affected skin in JLS and may help to differentiate between activity (thicker, less well perfused skin) and damage (thinner, highly perfused skin).

State-of-the-art technologies provide new insights linking skin and blood vessel abnormalities in SSc-related disorders.

OBJECTIVE: A key unanswered question in systemic sclerosis (SSc) is how microvascular abnormality and fibrosis inter-relate. Our aim was to use state-of-the-art non-invasive imaging methods to gain new insights into pathophysiology, comparing patients with different subtypes of SSc, including early dcSSc, not only to healthy controls but also to patients with causes of Raynaud's phenomenon not progressing to fibrosis. METHODS: Laser Doppler imaging, nailfold capillaroscopy, spectroscopy, and ultrasound measured (respectively) perfusion, microvascular structure, oxygenation/oxidative stress, and skin thickening in the hands of 265 subjects: 31 patients with primary Raynaud's phenomenon (PRP), 35 with undifferentiated connective tissue disease (UCTD), 93 with limited cutaneous SSc (lcSSc), 46 with diffuse cutaneous SSc (dcSSc, including 27 'early') and 60 healthy controls. RESULTS: Mean perfusion was reduced in SSc groups compared to controls (lcSSc 172 perfusion units [standard deviation 157], late-dcSSc 90 [145], early-dcSSc 68 [137] vs. controls 211 [146]; p = 0.0002) as was finger-oxygenation (lcSSc 12.1 [13.6] arbitrary units [AU], late-dcSSc 12.2 [8.4], early-dcSSc 11.1 [11.3] vs controls 14.9 [10.5]; p = 0.0049). Oxidative stress was increased at the hand-dorsum in SSc groups (p = 0.0007). Perfusion positively correlated with oxygenation (r = 0.23, p < 0.001), and capillary density negatively with skin thickness (r = -0.26, p < 0.001). CONCLUSION: Our findings lend support to the hypothesis that in SSc, particularly early dcSSc, (but not in PRP or UCTD), reduced perfusion (together with structural microvascular abnormality) associates with reduced oxygenation, with oxidative stress and with skin thickening/fibrosis, most likely driving a vicious cycle which ultimately results in irreversible tissue injury. Findings in skin may mirror alterations in internal organs.

Nailfold capillaroscopy-how many fingers should be examined to detect abnormality?

Objectives: Nailfold capillaroscopy is being increasingly used by rheumatologists in the diagnosis of SSc. However, assessment of all nailfolds can be time-consuming in a busy outpatient clinic. Our aim was to answer the question as to how many (and which) fingers a clinician should routinely assess to capture accurately the true state. Methods: A total of 2994 assessments (by an international panel of expert observers) of 1600 images from 173 participants (101 with SSc, 22 with primary RP and 50 healthy controls) were included in this analysis. Seven single-finger or finger combinations (derived from the middle and ring fingers) were then tested for sensitivity for the presence of two markers of capillary abnormality [presence of giant capillaries and an SSc grade (early, active or late)] compared with assessment of all eight fingers. Results: For the eight-finger gold standard, sensitivity against the diagnostic criteria was 74.6% (53.0% for the presence of giants alone and 73.1% for image grade alone). Examining only one finger gave low sensitivity (ranging from right middle 31.7% to left ring 46.6%). Examining both ring fingers gave a sensitivity of 59.8%, whereas examining the four-finger combination of both ring and both middle fingers gave a sensitivity of 66.7%. Conclusion: During routine capillaroscopic examination, ideally all eight nailbeds (excluding thumbs) should be examined, otherwise some abnormalities will be missed. Examining only four fingers reduces capillaroscopy sensitivity.

The Scleroderma Patient-Centered Intervention Network Cohort: baseline clinical features and comparison with other large scleroderma cohorts.

Objectives: The Scleroderma Patient-centered Intervention Network (SPIN) Cohort is a web-based cohort designed to collect patient-reported outcomes at regular intervals as a framework for conducting trials of psychosocial, educational, self-management and rehabilitation interventions for patients with SSc. The aim of this study was to present baseline demographic, medical and patient-reported outcome data of the SPIN Cohort and to compare it with other large SSc cohorts. Methods: Descriptive statistics were used to summarize SPIN Cohort characteristics; these were compared with published data of the European Scleroderma Trials and Research (EUSTAR) and Canadian Scleroderma Research Group (CSRG) cohorts. Results: Demographic, organ involvement and antibody profile data for SPIN (N = 1125) were generally comparable with that of the EUSTAR (N = 7319) and CSRG (N = 1390) cohorts. There was a high proportion of women and White patients in all cohorts, though relative proportions differed. Scl70 antibody frequency was highest in EUSTAR, somewhat lower in SPIN, and lowest in CSRG, consistent with the higher proportion of interstitial lung disease among dcSSc patients in SPIN compared with in CSRG (48.5 vs 40.3%). RNA polymerase III antibody frequency was highest in SPIN and remarkably lower in EUSTAR (21.1 vs 2.4%), in line with the higher prevalence of SSc renal crisis (4.5 vs 2.1%) in SPIN. Conclusion: Although there are some differences, the SPIN Cohort is broadly comparable with other large prevalent SSc cohorts, increasing confidence that insights gained from the SPIN Cohort should be generalizable, although it should be noted that all three cohorts include primarily White participants.

Automated structure and flow measurement - a promising tool in nailfold capillaroscopy.

OBJECTIVES: Despite increasing interest in nailfold capillaroscopy, objective measures of capillary structure and blood flow have been little studied. We aimed to test the hypothesis that structural measurements, capillary flow, and a combined measure have the predictive power to separate patients with systemic sclerosis (SSc) from those with primary Raynaud's phenomenon (PRP) and healthy controls (HC). METHODS: 50 patients with SSc, 12 with PRP, and 50 HC were imaged using a novel capillaroscopy system that generates high-quality nailfold images and provides fully-automated measurements of capillary structure and blood flow (capillary density, mean width, maximum width, shape score, derangement and mean flow velocity). Population statistics summarise the differences between the three groups. Areas under ROC curves (AZ) were used to measure classification accuracy when assigning individuals to SSc and HC/PRP groups. RESULTS: Statistically significant differences in group means were found between patients with SSc and both HC and patients with PRP, for all measurements, e.g. mean width (µm) ±â€¯SE: 15.0 ±â€¯0.71, 12.7 ±â€¯0.74 and 11.8 ±â€¯0.23 for SSc, PRP and HC respectively. Combining the five structural measurements gave better classification (AZ = 0.919 ±â€¯0.026) than the best single measurement (mean width, AZ = 0.874 ±â€¯0.043), whilst adding flow further improved classification (AZ = 0.930 ±â€¯0.024). CONCLUSIONS: Structural and blood flow measurements are both able to distinguish patients with SSc from those with PRP/HC. Importantly, these hold promise as clinical trial outcome measures for treatments aimed at improving finger blood flow or microvascular remodelling.

Intra-and inter-observer reliability of nailfold videocapillaroscopy - A possible outcome measure for systemic sclerosis-related microangiopathy.

OBJECTIVES: Our aim was to assess the reliability of nailfold capillary assessment in terms of image evaluability, image severity grade ('normal', 'early', 'active', 'late'), capillary density, capillary (apex) width, and presence of giant capillaries, and also to gain further insight into differences in these parameters between patients with systemic sclerosis (SSc), patients with primary Raynaud's phenomenon (PRP) and healthy control subjects. METHODS: Videocapillaroscopy images (magnification 300×) were acquired from all 10 digits from 173 participants: 101 patients with SSc, 22 with PRP and 50 healthy controls. Ten capillaroscopy experts from 7 European centres evaluated the images. Custom image mark-up software allowed extraction of the following outcome measures: overall grade ('normal', 'early', 'active', 'late', 'non-specific', or 'ungradeable'), capillary density (vessels/mm), mean vessel apical width, and presence of giant capillaries. RESULTS: Observers analysed a median of 129 images each. Evaluability (i.e. the availability of measures) varied across outcome measures (e.g. 73.0% for density and 46.2% for overall grade in patients with SSc). Intra-observer reliability for evaluability was consistently higher than inter- (e.g. for density, intra-class correlation coefficient [ICC] was 0.71 within and 0.14 between observers). Conditional on evaluability, both intra- and inter-observer reliability were high for grade (ICC 0.93 and 0.78 respectively), density (0.91 and 0.64) and width (0.91 and 0.85). CONCLUSIONS: Evaluability is one of the major challenges in assessing nailfold capillaries. However, when images are evaluable, the high intra- and inter-reliabilities suggest that overall image grade, capillary density and apex width have potential as outcome measures in longitudinal studies.

Quantitative outcome measures for systemic sclerosis-related Microangiopathy - Reliability of image acquisition in Nailfold Capillaroscopy.

BACKGROUND: Nailfold capillaroscopic parameters hold increasing promise as outcome measures for clinical trials in systemic sclerosis (SSc). Their inclusion as outcomes would often naturally require capillaroscopy images to be captured at several time points during any one study. Our objective was to assess repeatability of image acquisition (which has been little studied), as well as of measurement. METHOD: 41 patients (26 with SSc, 15 with primary Raynaud's phenomenon) and 10 healthy controls returned for repeat high-magnification (300×) videocapillaroscopy mosaic imaging of 10 digits one week after initial imaging (as part of a larger study of reliability). Images were assessed in a random order by an expert blinded observer and 4 outcome measures extracted: (1) overall image grade and then (where possible) distal vessel locations were marked, allowing (2) vessel density (across the whole nailfold) to be calculated (3) apex width measurement and (4) giant vessel count. Intra-rater, intra-visit and intra-rater inter-visit (baseline vs. 1week) reliability were examined in 475 and 392 images respectively. A linear, mixed-effects model was used to estimate variance components, from which intra-class correlation coefficients (ICCs) were determined. RESULTS: Intra-visit and inter-visit reliability estimates (ICCs) were (respectively): overall image grade, 0.97 and 0.90; vessel density, 0.92 and 0.65; mean vessel width, 0.91 and 0.79; presence of giant capillary, 0.68 and 0.56. These estimates were conditional on each parameter being measurable. CONCLUSION: Within-operator image analysis and acquisition are reproducible. Quantitative nailfold capillaroscopy, at least with a single observer, provides reliable outcome measures for clinical studies including randomised controlled trials.

Non-invasive Imaging of Localised Scleroderma for Assessment of Skin Blood Flow and Structure.

Extensive morphoea causes major morbidity, disability and disfigurement; pathophysiology is poorly understood. The aim of this study was to investigate, with non-invasive imaging, the relationship between localised abnormalities of skin structure and perfusion, which characterise morphoea. Thirty-two patients with morphoea underwent imaging at affected and unaffected sites. Skin thickness was imaged with optical coherence tomography (OCT) and high-frequency ultrasound (HFUS). Perfusion was imaged with dual-wavelength laser Doppler imaging (LDI) and thermography. Epidermal thickness showed a small increase from affected to unaffected site (OCT, active and inactive plaques [p = 0.005 and p = 0.004], HFUS active plaques only [p = 0.03]). Deeper perfusion was higher within affected than unaffected sites (LDI p < 0.001, thermography p < 0.0001, active and inactive plaques). Epidermal thickness was inversely related to superficial (but not deeper) perfusion. This novel study of OCT, HFUS, LDI and thermography confirms loss of epidermal thickness and increased deeper perfusion in morphea plaques.

A longitudinal study of ankle brachial pressure indices in a cohort of patients with systemic sclerosis.

OBJECTIVES: Digital ischaemia, often progressing beyond RP to digital ulceration and sometimes even gangrene, is the most common vascular manifestation of SSc. Both microvascular and macrovascular disease can contribute and coexistence of microvascular and macrovascular (proximal vessel) disease in patients with SSc is potentially limb threatening. The aims of this study were to examine the change over time in the ankle brachial pressure index (ABPI) in a cohort of patients with SSc and to examine whether age, gender, smoking status, disease duration, disease subtype and ACA are associated with ABPI. METHODS: The clinical and laboratory data of 217 patients attending the SSc clinic at a tertiary referral centre and who had their ABPIs checked between 1996 and 2011 were reviewed retrospectively. Data were analysed to see how the ABPI changed with time and linear mixed effects modelling was used to determine which factors were associated with ABPI. RESULTS: In most patients with SSc, the ABPI remained constant over time [median rate of change 0 units/year, interquartile range (IQR) -0.01-0.01]. There was a significant association between lower ABPI and increasing age (P = 0.04), the limited cutaneous subtype of SSc (P = 0.01) and ACA positivity (P = 0.03). Additionally there was an association between ABPI and smoking status of borderline statistical significance (P = 0.08). CONCLUSION: This study provides further evidence for associations between the severity of vascular disease in patients with SSc and increasing age, smoking, limited cutaneous disease and positive ACA. Reassuringly, in most patients ABPI remains stable over time.

Mobile phone thermography of the toes in patients with systemic sclerosis-a pilot study.

Objectives: To investigate the hypotheses that in patients with SSc, the temperature gradient between the dorsum of the foot and toes (distal-dorsal difference [DDD]) is 'more negative' (toes cooler) than in healthy controls, is greatest along the first (great) toe and that the severities of thermographic abnormalities in the feet and hands are correlated. Methods: Thermographic images of the dorsum of each hand and foot were captured using a thermal camera attached to an iPhone in 40 patients with SSc and 20 healthy controls. DDDs along the fingers (index, middle, ring and little) and toes (great toe and 'others') were measured. Results: There was a non-significant trend for the great toes to be colder in patients with SSc than in controls. The mean great toe DDD was more negative in patients (right: -2.89°C, left: -2.91°C, mean: -2.90°C) than in controls (right: -2.36°C, left: -2.42°C, mean: -2.39°C) (P = 0.37 for mean values). Patients' great toes were colder than 'other' (lesser) toes (right: -2.58°C, left: -2.63°C), although not significantly. In patients with SSc, finger and great toe temperature gradients were correlated (r = 0.406, ρ = 0.01). Conclusion: Our findings suggest that the great toe is the coldest in patients with SSc and that patients with the coldest fingers tend to have the coldest toes. Severe RP symptoms in the hands should prompt podiatry assessment and foot care education. Mobile phone thermography is a convenient tool for assessing the digital vasculature but first requires validation in larger studies with a longitudinal component.