The emerging application of semi-quantitative and quantitative capillaroscopy in systemic sclerosis

Microvascular status in juvenile Sjögren's disease: the first nailfold videocapillaroscopy investigation

INTRODUCTION

Juvenile Sjögren's disease (jSjD) is a rare autoimmune disease characterized by exocrine gland involvement and systemic manifestations, including small vessel vasculitis and Raynaud's phenomenon (RP). We aimed to investigate the microvascular status in jSjD patients by nailfold videocapillaroscopy (NVC) and the potential correlations with clinical and serological features.

METHODS

Clinical data from thirteen consecutive jSjD patients (11 females and 2 males), with a mean age of 16 ± 4 years, diagnosed before 16 years of age (mean age at diagnosis 12 ± 3) according to the 2016 American College of Rheumatology/EULAR criteria for adult SjD, were collected including age- and sex-matched healthy controls (HCs). Clinical, laboratory, and instrumental data were collected, together with NVC examination. Non-specific and specific NVC parameters were investigated, such as capillary density, capillary dilations, giant capillaries, microhaemorrhages and abnormal shapes. Associations between NVC findings and clinical/serological features were explored and analysed using parametrical and non-parametrical tests.

RESULTS

Capillary density reduction correlated significantly with articular involvement (arthralgias) (p = 0.024). Microhaemorrhages correlated with lower C3 levels (p = 0.034). No specific NVC pattern for jSjD was identified, whereas abnormal capillary shapes were significantly higher in jSjD patients than HCs (p = 0.005). NVC abnormalities were not associated with SjD-specific instrumental tests (biopsy, imaging, Schirmer's test). RP was present in 8% of jSjD patients.

CONCLUSIONS

The reduction of capillary density, as well as microhaemorrhages at NVC analysis, are significantly associated with some clinical aspects like articular involvement and serum biomarkers (C3 reduction). The NVC is suggested as safe and further analysis in jSjD patients.

Vision transformer assisting rheumatologists in screening for capillaroscopy changes in systemic sclerosis: an artificial intelligence model

OBJECTIVES

The first objective of this study was to implement and assess the performance and reliability of a vision transformer (ViT)-based deep-learning model, an 'off-the-shelf' artificial intelligence solution, for identifying distinct signs of microangiopathy in nailfold capilloroscopy (NFC) images of patients with SSc. The second objective was to compare the ViT's analysis performance with that of practising rheumatologists.

METHODS

NFC images of patients prospectively enrolled in our European Scleroderma Trials and Research group (EUSTAR) and Very Early Diagnosis of Systemic Sclerosis (VEDOSS) local registries were used. The primary outcome investigated was the ViT's classification performance for identifying disease-associated changes (enlarged capillaries, giant capillaries, capillary loss, microhaemorrhages) and the presence of the scleroderma pattern in these images using a cross-fold validation setting. The secondary outcome involved a comparison of the ViT's performance vs that of rheumatologists on a reliability set, consisting of a subset of 464 NFC images with majority vote-derived ground-truth labels.

RESULTS

We analysed 17 126 NFC images derived from 234 EUSTAR and 55 VEDOSS patients. The ViT had good performance in identifying the various microangiopathic changes in capillaries by NFC [area under the curve (AUC) from 81.8% to 84.5%]. In the reliability set, the rheumatologists reached a higher average accuracy, as well as a better trade-off between sensitivity and specificity compared with the ViT. However, the annotators' performance was variable, and one out of four rheumatologists showed equal or lower classification measures compared with the ViT.

CONCLUSIONS

The ViT is a modern, well-performing and readily available tool for assessing patterns of microangiopathy on NFC images, and it may assist rheumatologists in generating consistent and high-quality NFC reports; however, the final diagnosis of a scleroderma pattern in any individual case needs the judgement of an experienced observer.

Ultrasound quantitative assessment of ventral finger microvasculopathy in systemic sclerosis with Raynaud's phenomena: a comparative study

OBJECTIVE

To assess the finger vascularity of systemic sclerosis patients with Raynaud's phenomenon (RP-SSc) using various ultrasound techniques.

METHODS

All fingers (except thumbs) of 18 RP-SSc patients and 18 controls were imaged at room temperature using four ultrasound vascular imaging techniques. The percent vascular area was quantified by counting blood flow pixels in a 25 mm² square centred at the nail fold for the dorsal side and in 25 mm² and 100 mm² square from the fingertip for the ventral side. The mean vascular intensity was calculated from the corresponding areas for dorsal and ventral sides.

RESULTS

The percent vascular areas and mean vascular intensities in RP-SSc were significantly lower than those in controls for both dorsal and ventral sides (p<0.01). The mean vascular intensities showed slightly higher area under the curve (AUC) than the percent vascular areas (0.53-0.91 vs 0.53-0.90) regardless of imaging technique and assessment side. For each imaging technique, the ventral side vascularity showed a higher AUC (0.74-0.91) compared with the dorsal side (0.53-0.81). Moreover, ventral side abnormalities were associated with a history of digital ulcers.

CONCLUSIONS

Ultrasound demonstrated potential to quantify finger vascularity of RP-SSc. The ventral side of the fingers showed a higher accuracy in detecting RP-SSc than the dorsal side.

Systemic sclerosis in adults. Part I: Clinical features and pathogenesis

Systemic sclerosis (SSc), also referred to as systemic scleroderma or scleroderma, is a rare, complex immune-mediated connective tissue disease characterized by progressive skin fibrosis and other clinically heterogenous features. The etiopathogenesis of SSc involves vasculopathy and immune system dysregulation occurring on a permissive genetic and epigenetic background, ultimately leading to fibrosis. Recent developments in our understanding of disease-specific autoantibodies and bioinformatic analyses has led to a reconsideration of the purely clinical classification of diffuse and limited cutaneous SSc subgroups. Autoantibody profiles are predictive of skin and internal organ involvement and disease course. Early diagnosis of SSc, with commencement of disease-modifying treatment, has the potential to improve patient outcomes. In SSc, many of the clinical manifestations that present early signs of disease progression and activity are cutaneous, meaning dermatologists can and should play a key role in the diagnosis and management of this significant condition. The first article in this continuing medical education series discusses the epidemiology, clinical characteristics, and pathogenesis of SSc in adults, with an emphasis on skin manifestations, the important role of dermatologists in recognizing these, and their correlation with systemic features and disease course.

Diagnosis and Management of Cutaneous Manifestations of Autoimmune Connective Tissue Diseases

The cutaneous features of autoimmune connective tissue disease pose a unique challenge to patients and clinicians managing these conditions. In this review, we outline the key elements of diagnosis and treatment of cutaneous lupus erythematosus, dermatomyositis, systemic sclerosis, and morphea. This article also aims to present an update on gold standard as well as new and emerging therapies for these conditions. Overall, dermatologists can play a key role in diagnosing and treating autoimmune connective tissue diseases and this review intends to provide an up-to-date toolkit to guide clinical dermatologists in this endeavor.

Microvascular capillaroscopic abnormalities and occurrence of antinuclear autoantibodies in patients with sarcoidosis

We described nailfold videocapillaroscopy (NVC) findings and estimated the prevalence of serum anti-nuclear (ANA) and extractable nuclear antigen autoantibodies (ENA) in a cohort of sarcoidosis patients, comparing them with adequate healthy controls (HCs) and with primary Raynaud’s phenomenon patients (PRPs). NVC findings were also correlated with the occurrence of autoantibodies, current treatment, laboratory parameters, variables of lung function and whole-body imaging data. Twenty-six patients with sarcoidosis were assessed through NVC, laboratory parameters, pulmonary function tests, chest-X ray and 18- fluorodeoxyglucose positron emission tomography/computed tomography. The NVC parameters and ANA/ENA dosage were recorded also in 30 PRPs and 30 HCs. Sarcoidosis patients showed a higher rate of capillary dilations and nonspecific abnormalities and a lower mean capillary absolute number than PRPs and HCs (p < 0.01 for all comparisons). The prevalence of ANA positivity was higher in patients with sarcoidosis compared with PRPs and HCs (p < 0.02 for both), whereas ENA positivity was detected in one sarcoidosis patient (Ro52). Among sarcoidosis patients, the mean capillary absolute number negatively correlated with the C-reactive protein concentrations and was positively associated with the forced vital capacity percentage. Instead, a negative correlation was detected between serum ACE levels and the presence of capillary dilations (all p < 0.05). Our findings suggest a microvascular involvement in sarcoidosis whose investigation by NVC might be useful for the follow-up of patients displaying RP. Autoantibody positivity in sarcoidosis might suggest autoimmune implications in the disease or the production of autoantibodies reactive to tissue damage.

Nailfold Video Capillaroscopy in Pregnant Women With and Without Cardiovascular Risk Factors

Objective

To evaluate microvasculature in pregnant women with and without cardiovascular risk factors.

Design

Cross-sectional, observational study.

Population

Women were recruited at the outpatient clinic for high risk prenatal care. Out of a total of 345 women assessed at first and/or second and/or third trimester, 169 women without and 176 with cardiovascular risk factors were included.

Methods

Nailfold video capillaroscopy (NVC) measurements were performed at magnification of 200x at all fingers except thumbs. Images were stored for offline measurement of capillary density (CDe) and capillary diameters (CDi). Maternal anthropometrics, obstetric, and medical history were used for categorization in low and high cardiovascular risk. Comparison between groups and trimesters, with respect to pregnancy outcome, was performed using linear mixed model analysis.

Results

Women with a high risk cardiovascular profile show higher CDe, regardless of pregnancy outcome. CDi drops during pregnancy, with lowest CDi in third trimester in patients with preeclampsia. Capillary bed (CB), as a composite of CDe and CDi, is stable during pregnancy in women with low risk cardiovascular profile. In women with high risk cardiovascular profile, CB drops from the first to the second trimester, regardless of pregnancy outcome. Only in women with pre-eclampsia, the CB is lower in the third trimester as compared to the first trimester.

There is an inverse association between CDe and mean arterial pressure (MAP) in women with high cardiovascular risk and pre-eclampsia.

Conclusion

Microcirculation is altered during the course of pregnancy and microcirculatory behavior is different in patients with low and high cardiovascular risk profile, as well as in patients with preeclampsia.

Nailfold capillaroscopy in systemic diseases: short overview for internal medicine

Nailfold capillaroscopy (NFC) is now one of the main imaging tools in systemic sclerosis and imposed over time as an easy, non-invasive method for the nailfold microvascular bed assessment. In qualitative NFC normal pattern is characterized by homogeneous, parallel fashion arrangement of the last capillaries row as well as by capillaries with hairpin or non-specific variations like tortuous and/ or crossing shape. Nailfold capillaroscopy is strongly recommended for evaluation of all patients with Raynaud phenomenon. Appearance of giant capillaries is chronologically the first relevant finding for scleroderma spectrum disorders development (systemic sclerosis, dermatomyositis, undifferentiated and mixed connective tissue disease). Collapses of the giant loops generate microhemorrhages and further capillary loss with subsequent hypoxia, and neoangiogenesis seen as ramified/ bushy capillaries. Nailfold capillaroscopy is indicated especially in systemic sclerosis, being also included in the classification criteria. Based on these major NFC pathologic findings (giant capillaries, microhemorrhages, avascularity and neoangiogenesis), three evolutive stages were described in systemic sclerosis, namely the early, active, and late scleroderma pattern. In other connective tissue diseases than those scleroderma-related, like systemic lupus erythematosus, psoriatic arthritis, or antiphospholipid syndrome, the interest for capillaroscopy is growing, but the attempts of defining specific characteristics failed until now. Besides qualitative NFC, semiquantitative and quantitative capillaroscopic assessments were proposed for more accurate evaluation. Lately, automated systems are under development. There is still need of more studies to sustain the nailfold capillaroscopy validity as diagnostic and prognostic test.

Quantitative nailfold capillaroscopy-update and possible next steps

We review the exciting potential (and challenges) of quantitative nailfold capillaroscopy, focusing on its role in systemic sclerosis. Quantifying abnormality, including automated analysis of nailfold images, overcomes the subjectivity of qualitative/descriptive image interpretation. First we consider the rationale for quantitative analysis, including the potential for precise discrimination between normal and abnormal capillaries and for reliable measurement of disease progression and treatment response. We discuss nailfold image acquisition and interpretation, and describe how early work on semi-quantitative and quantitative analysis paved the way for semi-automated and automated analysis. Measurement of red blood cell velocity is described briefly. Finally we give a personal view on 'next steps'. From a clinical perspective, increased uptake of nailfold capillaroscopy by general rheumatologists could be achieved via low-cost hand-held devices with cloud-based automated analysis. From a research perspective, automated analysis could facilitate large-scale prospective studies using capillaroscopic parameters as possible biomarkers of systemic sclerosis-spectrum disorders.

Retinal microcirculation abnormalities in patients with systemic sclerosis: an explorative optical coherence tomography angiography study

OBJECTIVES

To investigate subclinical or clinical abnormalities in retinal and choroidal vascular plexuses in patients with systemic sclerosis (SSc) by means of optical coherence tomography angiography (OCT-A).

METHODS

A total of 20 consecutive SSc patients were recruited and compared to 20 healthy subjects. Quantitative analysis of vessel density (VD), choriocapillaris plexus flow index (CCP-FI) and choroidal vascularity index were performed on OCT-A images in the superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillaris for all patients. Images were further reviewed by two independent readers for the assessment of qualitative abnormalities, including tortuosity, rarefaction areas, megacapillaries and macular-foveal capillaries (MFC).

RESULTS

The DCP-VD in the whole scan and in parafoveal, superior, inferior, nasal and temporal regions was significantly lower in the SSc group. The CC-FI was significantly higher in SSc patients. When comparing SSc patients with and without digital ulcers (DUs), significantly reduced SCP-VD was demonstrated in the whole, parafoveal, superior, inferior, temporal and nasal regions. No difference in any of the OCT-A parameters was observed when comparing patients with or without interstitial lung disease (ILD). Qualitative analysis of OCT-A revealed at least one abnormality in 95% of patients.

CONCLUSIONS

We showed the ability of OCT-A to disclose early ocular vascular abnormalities in patients with SSc. Our results may represent a hypothesis-generating basis for exploring the potential role of OCT-A in diagnosis, monitoring and prognosis stratification in SSc.

Does sublingual microscopy correlate with nailfold videocapillaroscopy in systemic sclerosis?

In this study, we examine sublingual videomicroscopy and nailfold videocapillaroscopy (NVC) features in systemic sclerosis (SSc) patients presenting for routine care. Consented participants met classification criteria for SSc. Sublingual videomicroscopy testing was performed in each subject, followed by a NVC assessment. Sublingual assessment provided a density measurement, red blood cell fraction (RBC fract), and perfused boundary region (PBR) score. NVC evaluator defined nailfold findings as normal; specific changes for "early," "active," and "late" scleroderma pattern; or "non-specific" changes. Microangiopathy evolution score was calculated for each participant. Statistical evaluation was performed by non-parametric tests to assess the correlation of the two tools. Thirty-nine SSc patients with limited cutaneous disease participated in this study. Most participants had late pattern NVC. There was a highly significant association between the total sublingual microvascular density and number of capillaries measured by NVC (r = 0.569, P = 0.0002), and statistically significant negative correlation between sublingual total microvascular density and microangiopathy evolution score (r = 0.532, P = 0.0006). There was significant, negative correlation between the total sublingual microvascular density and disorganization of vascular array and capillary ramification (r = 0.461, P = 0.003) and degree of giant capillaries (r = 0.387, P = 0.01). There was no correlation between RBC fract and PBR with NVC parameters. This study showed a significant correlation between sublingual videomicroscopy and NVC in terms of sublingual total microvascular density and microangiopathy evolution score. These preliminary results further support the serial use of a non-invasive and automated sublingual microvascular function testing and glycocalyx measurement in the clinical setting. KEY POINTS: • Tools that longitudinally assess microvascular function and morphologic features are important for monitoring SSc vasculopathy. • Nailfold and sublingual microscopy can identify a loss of capillary density in SSc patients.

Three-dimensional optoacoustic imaging of nailfold capillaries in systemic sclerosis and its potential for disease differentiation using deep learning

The autoimmune disease systemic sclerosis (SSc) causes microvascular changes that can be easily observed cutaneously at the finger nailfold. Optoacoustic imaging (OAI), a combination of optical and ultrasound imaging, specifically raster-scanning optoacoustic mesoscopy (RSOM), offers a non-invasive high-resolution 3D visualization of capillaries allowing for a better view of microvascular changes and an extraction of volumetric measures. In this study, nailfold capillaries of patients with SSc and healthy controls are imaged and compared with each other for the first time using OAI. The nailfolds of 23 patients with SSc and 19 controls were imaged using RSOM. The acquired images were qualitatively compared to images from state-of-the-art imaging tools for SSc, dermoscopy and high magnification capillaroscopy. The vascular volume in the nailfold capillaries were computed from the RSOM images. The vascular volumes differ significantly between both cohorts (0.216 ± 0.085 mm³ and 0.337 ± 0.110 mm³; p < 0.0005). In addition, an artificial neural network was trained to automatically differentiate nailfold images from both cohorts to further assess whether OAI is sensitive enough to visualize anatomical differences in the capillaries between the two cohorts. Using transfer learning, the model classifies images with an area under the ROC curve of 0.897, and a sensitivity of 0.783 and specificity of 0.895. In conclusion, this study demonstrates the capabilities of RSOM as an imaging tool for SSc and establishes it as a modality that facilitates more in-depth studies into the disease mechanisms and progression.

Capillary loss reflects disease activity and prognosis in patients with systemic sclerosis

Capillary density on nailfold capillaroscopy (NFC) is considered a promising instrument for assessing disease characteristics in patients with systemic sclerosis (SSc), however, there is no agreement yet over how to analyze and interpret the results. The objective of this study was to investigate the possible associations of the mean number of capillaries with disease characteristics, disease activity [measured by the European Scleroderma Study Group (EScSG) disease activity score] and survival in a single-center cohort of patients with SSc. Sixty-eight patients were included; 54 had follow-up at 6 months. Thirty-two images per patient were assessed independently by two raters, scoring the mean number of capillaries in all fingers (N), in the 3rd finger of the dominant hand (dN₃) and in the 4th finger of the non-dominant hand (ndN₄) for each patient. NFC 'early', 'active' and 'late' patterns were also assessed. Two thousand and seventy-six images were scored at baseline, 1,728 at follow-up. Baseline N was median (IQR) 5.1 (2.7) for rater 1, and 4.9 (1.7) for rater 2, respectively. N was significantly lower in patients with a history of digital ulcers (DUs), vs. those who never had DUs 4.8 (1.4) vs. 6.4 (3.1), P=0.016. A lower N was associated with higher disease activity at baseline and follow-up (linear regression adjusted for age, sex and history of DUs). A lower ndN₄ was associated with increased mortality (logistic regression adjusted for age and sex). In conclusion, in patients with SSc, a lower mean number of capillaries assessed by NFC was associated with higher disease activity after 6 months of follow-up and with shorter survival.

Progression of nailfold capillaroscopic patterns and correlation with organ involvement in systemic sclerosis: a 12 year study

OBJECTIVE

The aim of this observational study was to investigate the evolution of scleroderma microangiopathy throughout different nailfold videocapillaroscopy (NVC) patterns ('early', 'active', 'late') as well as the prevalence of organ involvement in SSc patients during a 12-year follow-up.

METHODS

Thirty-four SSc patients showing at baseline (first capillaroscopic analysis) the 'early' NVC pattern of microangiopathy were enrolled and followed for 12 years (s.d. 2). Complete NVC analysis and clinical and serological findings were collected. Patients were in a standard therapeutic care setting. Statistical analysis was carried out by non-parametric tests.

RESULTS

After a 12-year follow-up, the 'early' NVC pattern changed from baseline in 76% of the patients. The NVC pattern was found to be 'active' in 9 patients (26%), 'late' in 13 (38%) and characterized by non-specific capillary abnormalities in 4 (12%). In the subgroup whose microangiopathy progressed from the 'early' to the 'late' NVC pattern, the median time of progression from the 'early' to the 'active' pattern was significantly shorter (11 months) when compared with patients who progressed from the 'early' to the 'active' NVC pattern (55 months) (P = 0.002). The median time of progression between NVC patterns was significantly shorter in SSc patients showing either a nucleolar ANA pattern or Scl70 autoantibodies (P = 0.048). Organ involvement was progressively greater in SSc patients with 'early', 'active' and 'late' NVC patterns, respectively.

CONCLUSIONS

This longitudinal study confirms over a 12-year follow-up the evolution of specific NVC patterns associated with the progressive severity of organ involvement in SSc patients in a standard clinical care setting.

Raynaud phenomenon and digital ulcers in systemic sclerosis

Raynaud phenomenon is a symptom complex caused by impaired digital perfusion and can occur as a primary phenomenon or secondary to a wide range of underlying causes. Raynaud phenomenon occurs in virtually all patients with systemic sclerosis (SSc) and is often the earliest clinical manifestation to occur. Careful assessment is required in patients with Raynaud phenomenon to avoid missing secondary causes such as SSc. Digital ulcers are a painful and disabling visible manifestation of digital vascular injury in patients with SSc. Progress has been made in the classification and assessment of digital ulcers and in understanding ulcer pathogenesis, and there are a wide range of treatments available to both prevent and heal digital ulcers, some of which are also used in Raynaud phenomenon management. In this Review, the assessment of patients with Raynaud phenomenon is discussed, including 'red flags' that are suggestive of SSc. The pathogenesis, classification and assessment of SSc-associated digital ulcers are also covered, alongside an overview of management approaches for SSc-associated Raynaud phenomenon and digital ulcers. Finally, unmet needs are discussed and the concept of a unified vascular phenotype in which therapies that affect the vasculature to support disease modification strategies is introduced.

Bridging the gap between basic research on microcirculation and clinical world: The translational marriage between engineering and medicine

The words "Translational" and "Medicine" have been recently coupled to indicate a combination of disciplines, resources, expertise, and techniques aimed at enhancing prevention, diagnosis, and therapies. As stated in 2015 by the European Society for Translational Medicine, translational medicine is "an interdisciplinary branch of the biomedical field supported by three main pillars: benchside, bedside and community". By definition, Translational Medicine is a highly interdisciplinary field, which gathers several specialties aimed at improving the global healthcare system.With regard to the assessment of the microcirculatory function, it is worthwhile to mention the growing interest from both basic research and clinical practice. Microcirculation is where the exchange of substances between blood and tissues takes place. Thus, it plays a key role in the pathophysiology of many diseases. Nonetheless, a gap does exist between the theoretical analysis of the microcirculatory function and its clinical exploitation. This gap can be due to the weak dissemination of analytical methods and theoretical results within the clinical community, which also delays the establishment of specific operative guidelines.This paper aims at encouraging, and possibly accelerating, the translation of basic research outcomes on microcirculatory function assessment into clinical applications.