Nailfold Capillaroscopy and Clinical Applications in Systemic Sclerosis

Nailfold capillary abnormalities are associated with increased severity of Raynaud phenomenon among patients with systemic sclerosis: a pilot study

We conducted a retrospective review of patients with systemic sclerosis, finding that nailfold capillary abnormalities are significantly associated with more aggressive treatment of Raynaud phenomenon, specifically the use of calcium channel blockers and other vasodilators compared with topical therapy or no treatment. This relationship indicates that routine nailfold capillary examination may assist in Raynaud phenomenon risk stratification. It also highlights the need for further research on whether nailfold capillaries may be a noninvasive marker of more severe vascular complications within systemic sclerosis.

Nailfold videocapillaroscopy in antineutrophil cytoplasmic antibody-associated vasculitis

OBJECTIVE

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of illnesses that cause inflammation and alterations to small vessels in the body. Some of the most common and detrimental manifestations, including alveolar hemorrhage and glomerulonephritis, are caused by this capillary inflammation. We sought to clarify whether patients with AAV would have abnormal nailfold capillaries when evaluated with nailfold videocapillaroscopy.

METHODS

Patients with a current diagnosis of AAV and a control group were identified for enrollment. Nailfold videocapillaroscopy images were used for a semiquantitative analysis on capillary density, morphology, dilation, and microhemorrhage after review by 2 rheumatologists. Disease characteristics, occurrence of recent disease flare, and presence of ANCA were recorded.

RESULTS

Thirty-three patients with a diagnosis of AAV and 21 controls were recruited. The AAV group had a median age of 59 and 17 (52%) were women. Granulomatosis with polyangiitis was the most common diagnosis (19 [58%]), followed by eosinophilic granulomatosis with polyangiitis (7 [21%]) and microscopic polyangiitis (7 [21%]). Twenty-seven patients (82%) had positive ANCA tests. After assessment of capillary density, dilation, morphology, microhemorrhages, and disorganization, there were no statistically significant differences between the 2 groups.

CONCLUSION

There was no evidence of differences in nailfold capillaroscopy abnormalities between those diagnosed with AAV and the control group. While this cohort was relatively small, we did not find a high enough prevalence or specific phenotype of capillary abnormalities that could aid in diagnosis or prognostication of these diseases in the clinical setting.

Red Blood Cells' Area Deformation as the Origin of the Photoplethysmography Signal

The origin of the photoplethysmography (PPG) signal is a debatable topic, despite plausible models being addressed. One concern revolves around the correlation between the mechanical waveform's pulsatile nature and the associated biomechanism. The interface between these domains requires a clear mathematical or physical model that can explain physiological behavior. Describing the correct origin of the recorded optical waveform not only benefits the development of the next generation of biosensors but also defines novel health markers. In this study, the assumption of a pulsatile nature is based on the mechanism of blood microcirculation. At this level, two interconnected phenomena occur: variation in blood flow velocity through the capillary network and red blood cell (RBC) shape deformation. The latter effect was qualitatively investigated in synthetic capillaries to assess the experimental data needed for PPG model development. Erythrocytes passed through 10 µm and 6 µm microchannel widths with imposed velocities between 50 µm/s and 2000 µm/s, according to real scenarios. As a result, the length and area deformation of RBCs followed a logarithmic law function of the achieved traveling speeds. Applying radiometric expertise on top, mechanical-optical insights are obtained regarding PPG's pulsatile nature. The mathematical equations derived from experimental data correlate microcirculation physiologic with waveform behavior at a high confidence level. The transfer function between the biomechanics and the optical signal is primarily influenced by the vasomotor state, capillary network orientation, concentration, and deformation performance of erythrocytes.

Computerized nailfold video-capillaroscopy in type 2 diabetes: A cross-sectional study on 102 outpatients

BACKGROUND

Type 2 diabetes (T2D) is a chronic disease that negatively affects vascular health. A careful assessment of chronic complications, including microcirculation, is mandatory. The computerized nailfold video-capillaroscopy (CNVC) accurately examines the nailfold microvasculature, but its suitability in T2D is currently under investigation.

AIMS

To describe nailfold microvasculature in T2D patients regarding the level of glucose control and chronic microvascular and macrovascular complications.

METHODS

This is a cross-sectional study on 102 consecutive and unselected outpatients with T2D who had undergone CNVC examination. The examination was carried out by using an electronic video-capillaroscope with 300x magnification. Capillaroscopic appearance and capillary changes were described according to well-established parameters. Capillaroscopic parameters were compared between patients with poor glucose control (HbA1c ≥7%) and those with better glucose control (HbA1c <7%) and between patients with chronic complications and those without. Chronic complications were deduced from the anamnestic, laboratory, and instrumental data and the five-item International Index of Erectile Function (IIEF-5) questionnaire.

RESULTS

Nailfold capillaries in patients with HbA1c ≥7% were thicker (p = .019) and longer (p = .021) than in those with better glucose control. Ectasias (p = .017) and microaneurysms (p = .045) were more frequently observed in patients with HbA1c ≥7.0% than those with HbA1c <7.0%. Patients with ED, compared to those without, had a lower frequency of bizarre-shaped capillaries (p = .02). Microaneurysms (p = .02) were more frequently described in patients with carotid stenosis (>20%) than those without.

CONCLUSION

Relevant nailfold microvascular alterations were observed in T2D, most of which were associated with poor glycemic control, ED, and carotid stenosis. Further investigation is needed to recognize the role of CNVC in predicting the onset and evolution of chronic complications and monitoring the effectiveness of antihyperglycemic treatments on microcirculation.

Possibilities of non-invasive diagnosis of fibrotic phenotype of interstitial lung diseases

Progressive pulmonary fibrosis is a major problem in respiratory medicine. Currently, there are no reliable biomarkers for early diagnosis of progressive pulmonary fibrosis, which leads to delayed diagnosis.

AIM

To determine the role of serum biomarkers CA-19-9 and CA-125 and the possibilities of capillaroscopy of the nail fold in the diagnosis of progressive pulmonary fibrosis.

MATERIALS AND METHODS

The study included 43 patients with interstitial changes in the lungs. Based on the presence/absence of signs of progression over the previous 12 months, patients were divided into 2 groups. All patients underwent forced spirometry, body plethysmography, diffusion test, CT, lung ultrasound, capillaroscopy of the nail fold, study of serum concentrations of CA-19-9 and CA-125.

RESULTS

In the group of patients with a progressive fibrotic phenotype of Interstitial lung diseases, a greater severity of capillaroscopic changes and a higher level of CA-19-9 were revealed. Correlation of these parameters with changes according to CT scan data (Warrick test) and lung ultrasound was shown.

CONCLUSION

The data obtained demonstrate the possibilities of non-invasive diagnosis of progressive fibrosing interstitial lung diseases and require further research and prospective follow-up to assess the diagnostic and prognostic role of the studied biomarkers, as well as to determine their place in clinical practice.

Nailfold video-capillaroscopy in the study of cardiovascular disease: a systematic review

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.

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 capillaroscopy: tips and challenges

Although nailfold capillaroscopy (NFC) appears to have a bright future in clinical practice, the lack of familiarity with the technique and how to interpret its outcomes is major barriers which have made nailfold capillaroscopy an underutilized method in standard clinical practice. Traditional methods for assessment and measurement of capillary patterns, density, and blood flow are falling behind and face some challenges. In fact, there have been calls for improvement, hence the recent publication of the standardization of NFC by the EULAR Study Group on Microcirculation in Rheumatic Diseases. Nailfold capillaroscopy has the advantage of being a non-invasive technique that provides a window into the digital microcirculation. This paved the way for a rapidly growing interest in using capillaroscopy parameters as outcome measures in research. In standard clinical practice, whilst its main application is in the identification of an underlying systemic sclerosis spectrum disorder in patients presenting with Raynaud's phenomenon, its use has expanded to include other clinical features possibly suggestive of an underlying connective tissue disease. This article presents the challenges, provides tips, and highlights the exciting potential of nailfold capillaroscopy in standard practice.

Eye Sign is an Alternative for Evaluation of the Microcirculation in Patients with Systemic Sclerosis

Objectives

To investigate consistency between eye sign and nailfold video capillaroscopy (NVC) in systemic sclerosis (SSc) patients and to evaluate eye sign with various parameters of disease and potential pulmonary involvement.

Methods

A total of 60 SSc patients and 20 healthy individuals were enrolled. 20 SSc patients were complicated with pulmonary arterial hypertension (PAH); 20 SSc patients with interstitial lung diseases (ILD); 20 SSc patients without pulmonary involvement. All subjects were assessed using the methods of NVC and eye sign. Skin involvement was evaluated by modified Rodnan skin score (mRSS) and disease activity according to Medsger's severity score (MSS). Clinical manifestations and the presence of autoantibodies were carefully recorded. Any correlations between were evaluated with the Spearman correlation coefficient test.

Results

According to the morphological changes revealed by NVC, 3 types of NVC patterns have been characterized (early pattern, active pattern, and late pattern). Eye sign showed distinguishing morphologic changes in three patterns of NVC and pulmonary involvements (PAH vs ILD) in SSc. A positive linear correlation was found between scores of eye sign and NVC in all patients with SSc (r = 0.629, P=0.001). A positive correlation of eye sign was found in all SSc patients with mRSS (r = 0.748, P=0.045) and MSS (r = 0.636, P=0.001).

Conclusions

The study demonstrates that eye sign had a high consistency with NVC for the evaluation of the microcirculation in SSc patients and exhibited specific patterns in the early, active, and late phases of SSc. Eye sign can be used as a reliable method to classify and monitor SSc patients and replace the measurement of NVC.

Understanding the value of non-specific abnormal capillary dilations in presence of Raynaud's phenomenon: a detailed capillaroscopic analysis

BACKGROUND

Nailfold videocapillaroscopy (NVC) non-specific abnormalities may be present in subjects with isolated Raynaud's phenomenon (RP) before the potential transition to systemic sclerosis (SSc) specific microvascular alterations ('scleroderma pattern'). This study aims to investigate NVC non-specific abnormalities, notably capillary dilations, in RP patients, as possible forerunners of the 'scleroderma pattern'.

METHODS

A 10-year retrospective NVC-based investigation evaluated 55 RP patients sorted into 3 sex-matched and age-matched groups according to clinical evolution: 18 later developing SSc (cases), 19 later developing other connective tissue disease and 18 maintaining primary RP at long-term follow-up (controls). All patients had a basal NVC showing non-specific abnormalities, namely non-specific &gt;30 µm dilated capillaries (30-50 μm diameter). Sequential NVCs were longitudinally evaluated using current standardised approach. Statistical analysis assessed the risk for developing a 'scleroderma pattern'.

RESULTS

Significantly larger capillary diameters were observed in cases versus controls both at basal NVC and during follow-up NVC (p=&lt;0.05 to &lt;0.001). Interestingly, controls showed stable NVC non-specific abnormalities over the study follow-up. The number of &gt;30 µm dilated capillaries/mm at basal NVC was the strongest single predictor of 'scleroderma pattern' evolution with 24% increased risk per each dilated capillary (OR 1.24, 95% CI 1.17,1.32). Additionally, a tree-based analysis suggested the efferent (venous) diameter of the most dilated capillary on basal NVCas a variable of interest to identify patients maintaining primary RP.

CONCLUSION

This is the first study to describe an NVC 'prescleroderma signature' to potentially identify RP patients later developing a 'scleroderma pattern'.

Automated capillary flow segmentation and mapping for nailfold video capillaroscopy

OBJECTIVE

This study aimed to develop an automated image analysis method for segmentation and mapping of capillary flow dynamics captured using nailfold video capillaroscopy (NVC). Methods were applied to compare capillary flow structures and dynamics between young and middle-aged healthy controls.

METHODS

NVC images were obtained in a resting state, and a region of the vessel in the image was extracted using a conventional U-Net neural network. The approximate length, diameter, and radius of the curvature were calculated automatically. Flow speed and its fluctuation over time were mapped using the Radon transform and frequency spectrum analysis from the kymograph image created along the vessel's centerline.

RESULTS

The diameter of the curve segment (14.4 μm and 13.0 μm) and the interval of two straight segments (13.7 μm and 32.1 μm) of young and middle-aged subjects, respectively, were significantly different. Faster flow was observed in older subjects (0.48 mm/sec) than in younger subjects (0.26 mm/sec). The power spectral analysis revealed a significant correlation between the high-frequency power spectrum and the flow speed.

CONCLUSIONS

The present method allows a spatiotemporal characterization of capillary morphology and flow dynamics with NVC, allowing a wide application such as large-scale health assessment.

Usability evaluation of a non-invasive neutropenia screening device (PointCheck™) for cancer chemotherapy patients: Observational Study (Preprint)

Background

Patients with cancer undergoing cytotoxic chemotherapy face an elevated risk of developing serious infection as a consequence of their treatment, which lowers their white blood cell count and, more specifically, their absolute neutrophil count. This condition is known as neutropenia. Neutropenia accompanied by a fever is referred to as febrile neutropenia, a common side effect of chemotherapy with a high mortality rate. The timely detection of severe neutropenia (<500 absolute neutrophil count/μL) is critical in detecting and managing febrile neutropenia. Current methods rely on blood draws, which limit them to clinical settings and do not allow frequent or portable monitoring. In this study, we demonstrated the usability of PointCheck, a noninvasive device for neutropenia screening, in a simulated home environment without clinical supervision. PointCheck automatically performs microscopy through the skin of the finger to image the blood flowing through superficial microcapillaries and enables the remote monitoring of neutropenia status, without requiring venipuncture.

Objective

This study aimed to evaluate the usability of PointCheck, a noninvasive optical technology for screening severe neutropenia, with the goal of identifying potential user interface, functionality, and design issues from the perspective of untrained users.

Methods

We conducted a multicenter study using quantitative and qualitative approaches to evaluate the usability of PointCheck across 154 untrained participants. We used a mixed method approach to gather usability data through user testing observations, a short-answer qualitative questionnaire, and a standardized quantitative System Usability Scale (SUS) survey to assess perceived usability and satisfaction.

Results

Of the 154 participants, we found that 108 (70.1%) scored above 80.8 on the SUS across all sites, with a mean SUS score of 86.1 across all sites. Furthermore, the SUS results indicated that, out of the 151 users who completed the SUS survey, 145 (96%) found that they learned how to use PointCheck very quickly, and 141 (93.4%) felt very confident when using the device.

Conclusions

We have shown that PointCheck, a novel technology for noninvasive, home-based neutropenia detection, can be safely and effectively operated by first-time users. In a simulated home environment, these users found it easy to use, with a mean SUS score of 86.1, indicating an excellent perception of usability and placing this device within the top tenth percentile of systems evaluated for usability by the SUS.

Trial Registration

ClinicalTrials.gov NCT04448314; https://clinicaltrials.gov/ct2/show/NCT04448314 (Hospital Universitario 12 de Octubre registration) and NCT04448301; https://clinicaltrials.gov/ct2/show/NCT04448301 (Boston Medical Center registration)

Nailfold videocapillaroscopic changes in patients with pulmonary arterial hypertension associated with connective tissue diseases

Pulmonary arterial hypertension (PAH) represents one of the most devastating complications in connective tissue diseases (CTDs). The aim of this study was to investigate the presence of peripheral microangiopathy in patients with PAH associated with CTDs (CTD-PAH) by exploring nailfold videocapillaroscopic (NVC) changes and identify possible associations of NVC characteristics with markers of disease severity. Α cross-sectional study was performed in 18 CTD-PAH patients [13 PAH due to systemic sclerosis (SSc-PAH) and 5 with other types of CTD-PAH], 14 patients with SSc without PAH (SSc-non-PAH) and 20 healthy controls. NVC quantitative and qualitative parameters were evaluated using Optilia Digital Capillaroscope. To ensure inter-observer repeatability, capillaroscopic images were reviewed by two independent investigators. When compared to healthy controls, patients with CTD-PAH (77.8% women, mean age 65.9 years) presented reduced capillary density (6.5 ± 1.6 loops/mm vs. 9.7 ± 0.7 loops/mm, p < 0.001) and increased capillary loop width (23.3 ± 10.1 μm vs. 11.2 ± 2.5 μm, p < 0.001). SSc-PAH patients presented lower capillary density in comparison with other CTD-PAH patients and SSc-non-PAH subjects and abnormal and disorganized capillaries compared to controls. Patients with other CTD-PAH had also reduced capillary density and increased loop diameter compared to controls. A significant linear correlation was identified between capillary density and estimated glomerular filtration rate in the total CTD-PAH population (r = 0.63, p = 0.007). In SSc-PAH group, capillary loop diameter was positively correlated to cardiac index (r = 0.61, p = 0.02). Significant NVC microvascular changes were detected in patients with various types of CTD-PAH, suggesting an impaired peripheral microcirculation parallel to pulmonary vasculopathy.

Microvascular damage - a marker of specific organ involvement in mixed connective tissue disease?

Mixed connective tissue disease (MCTD) is a complex entity, which incorporates features of systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), systemic sclerosis (SSc) and polymyositis/dermatomyositis (PM/DM). Nailfold videocapillaroscopy (NVC) is a simple, safe and non-invasive technique of capillary vessel assessment, allowing for qualitative and quantitative assessment of microcirculation. NVC plays a pivotal role in the diagnostic algorithm of connective tissue diseases, especially in systemic sclerosis (SSc). Numerous studies have shown a correlation between organ involvement and disease progression in SSc.

In the current literature, there are limited data on relationship between NVC and organ involvement in MCTD patients. In the present article the relevant literature describing NVC examination in patients with MCTD and comparisons with some clinical situations are discussed.

The Relationship between Pulmonary Damage and Peripheral Vascular Manifestations in Systemic Sclerosis Patients

Systemic sclerosis (SSc) is an autoimmune disease, characterized by the presence of generalized vasculopathy and tissue fibrosis. Collagen vascular disorder in SSc is due to fibroblast and endothelial cell dysfunctions. This leads to collagen overproduction, vascular impairment and immune system abnormalities and, in the last stage, multi-organ damage. Thus, to avoid organ damage, which has a poor prognosis, all patients should be carefully evaluated and followed. This is particularly important in the initial disease phase, so as to facilitate early identification of any organ involvement and to allow for appropriate therapy. Pulmonary disease in SSc mainly involves interstitial lung disease (ILD) and pulmonary arterial hypertension (PAH). High-resolution computed tomography (HRCT) and pulmonary function tests (PFT) have been proposed to monitor parenchymal damage. Although transthoracic echocardiography is the most commonly used screening tool for PAH in SSc patients, definitive diagnosis necessitates confirmation by right heart catheterization (RHC). Moreover, some studies have demonstrated that nailfold videocapillaroscopy (NVC) provides an accurate evaluation of the microvascular damage in SSc and is able to predict internal organ involvement, such as lung impairment. This review provides an overview of the correlation between lung damage and microvascular involvement in SSc patients.

Peripheral microangiopathy in precapillary pulmonary hypertension: a nailfold video capillaroscopy prospective study

Background

Although pulmonary vascular bed has been the main subject of research for many years in pulmonary hypertension (PH), interest has recently started to divert towards the possibility of a co-existing peripheral microangiopathy. The aim of the current study was to investigate the presence of nailfold video-capillaroscopic (NVC) structural changes in patients with precapillary PH and to identify possible associations of NVC measurements with markers of disease severity.

Methods

Α prospective case–control study was performed in 28 consecutive patients with precapillary PH [14 with idiopathic pulmonary arterial hypertension (IPAH) and 14 with chronic thromboembolic pulmonary hypertension (CTEPH)] and 30 healthy controls. NVC quantitative and qualitative parameters were evaluated using Optilia Digital Capillaroscope. To ensure inter-observer repeatability capillaroscopic images were reviewed by two independent investigators. For multiple comparisons among continuous variables, one-way ANOVA or the Kruskal–Wallis test were used. Differences between the groups were tested with post-hoc analysis with adjustment for multiple comparisons (Bonferroni test).

Results

Both IPAH (71.4% were women, mean age 53.1 ± 13.4 years) and CTEPH (64.3% women, mean age 60.9 ± 14.4 years) groups presented reduced capillary density compared to healthy controls (8.4 ± 1.2 loops/mm and 8.0 ± 1.2 loops/mm vs. 9.7 ± 0.81 loops/mm, p < 0.001) and increased loop width (15.7 ± 3.9 μm and 15.8 ± 1.9 μm vs. 11.5 ± 2.3 μm, p < 0.001). More than half of patients with IPAH presented microhaemorrhages on capillary nailfold, while increased shape abnormalities in capillary morphology and more capillary thrombi per linear mm were detected in patients with CTEPH compared to patients with IPAH and healthy controls. All PH patients presented a non-specific NVC pattern compared to controls (p < 0.001).

Conclusion

The findings of the study reveal a degree of significant peripheral microvascular alterations in patients with IPAH and CTEPH, suggesting a generalized impairment of peripheral microvasculature in pulmonary vascular disease.

Acromegaly Might Not Negatively Affect Microvascular Circulation

BACKGROUND

Endothelial dysfunction and atherosclerosis are well-known complications of acromegaly. However, current data on microvascular circulation are limited.

AIMS

We aimed to evaluate microvascular circulation in patients with acromegaly.

METHODS

This comparative study included a total of 21 patients with acromegaly and 20 age and sex-matched healthy subjects. A stereomicroscope under 100x magnification was used by a single rheumatologist to evaluate the capillary dimensions (capillary loop length, capillary width) and capillary/mm count in the capillaries of subjects. Statistical data analysis was conducted using the SPSS 15.0 package program.

RESULTS

The mean number of capillaries per ml (Normal ≥8 / ml) in the acromegaly group (AG) and healthy controls (HC) was 7.67 ± 1.88 and 8.67 ± 0.65, respectively (p = 0.04). In the AG and the HC, the number of tortuous capillaries, the mean capillary loop length and the mean capillary width were not different. While the median number of capillaries in the AG was lower than in the HC, it was still within normal limits.

CONCLUSION

Although the number of capillaries were statistically lower in patients with acromegaly, they were within a normal range and the difference was not clinically significant. Moreover, there was no difference in morphological characteristics between the groups. While endothelial dysfunction is the earliest known marker of the atherosclerotic process and is considered to be one of the complications of acromegaly, the disease may not result in impairment of microvasculature of those people afflicted by it. This article is protected by copyright. All rights reserved.

Nailfold videocapillaroscopy: a novel possible surrogate marker for the evaluation of peripheral microangiopathy in pulmonary arterial hypertension

Nailfold videocapillaroscopy (NVC) changes in systemic sclerosis (SSc) are correlated with vascular complications, such as pulmonary arterial hypertension (PAH), supporting a potential link between peripheral and internal organ vasculopathy. The current stage of knowledge regarding NVC and PAH is discussed, focusing on the assessment of peripheral microangiopathy and a potential relationship with functional, echocardiographic, and haemodynamic markers of cardiac dysfunction. A comprehensive literature search was carried out to identify all studies focusing on NVC findings in patients with PAH, diagnosed with right heart catheterization. The majority of the studies examined NVC findings in patients with SSc-PAH, while three studies reported NVC abnormalities in patients with idiopathic PAH. Besides the pulmonary vasculature, a systemic component of microangiopathy seems to be involved in PAH. Well-designed prospective trials are warranted to validate NVC as a biomarker, with clinical implications in the diagnostic evaluation, risk stratification, and overall management of PAH in the daily clinical setting.

Peripheral Microangiopathy in Patients with Precapillary Pulmonary Hypertension: Correlation with Cardiac Function and Patients' Functional Capacity. Study Design and Rationale

Pulmonary hypertension (PH) is a rare, heterogenous clinical entity characterised by a progressive remodelling of pulmonary arterioles, which leads to obstructive pulmonary arteriopathy, increased pulmonary vascular resistance, and eventually, right heart failure. Inflammation, endothelial dysfunction, and microvascular changes of the pulmonary vasculature constitute the hallmarks of pulmonary arterial hypertension (PAH), explaining much of the pathophysiology and clinical manifestations of the disease. Besides pulmonary vasculature, a systemic component of endothelial dysfunction and microcirculation may be involved in PAH, affecting different vascular beds. Nailfold videocapillaroscopy (NVC) is an established method for the assessment of the microvasculature with clinical implications in the diagnostic assessment of individuals with Raynaud syndrome and systemic sclerosis (SSc). Nowadays, growing amounts of evidence suggest that NVC changes in SSc are correlated with other vascular complications such as PAH, supporting a potential link between peripheral and internal organ vasculopathy. The purpose of the current prospective observational study is to explore: 1. the presence of peripheral microangiopathy in precapillary PH using NVC, 2. possible NVC differences among PH subgroups, 3. a potential relationship between NVC morphological abnormalities and clinical, functional, biochemical, echocardiographic and hemodynamic markers of cardiac dysfunction in precapillary PH.

Predictors of progression in systemic sclerosis patients with interstitial lung disease

Systemic sclerosis (SSc) is a systemic autoimmune disease affecting multiple organ systems, including the lungs. Interstitial lung disease (ILD) is the leading cause of death in SSc.

There are no valid biomarkers to predict the occurrence of SSc-ILD, although auto-antibodies against anti-topoisomerase I and several inflammatory markers are candidate biomarkers that need further evaluation. Chest auscultation, presence of shortness of breath and pulmonary function testing are important diagnostic tools, but lack sensitivity to detect early ILD. Baseline screening with high-resolution computed tomography (HRCT) is therefore necessary to confirm an SSc-ILD diagnosis. Once diagnosed with SSc-ILD, patients' clinical courses are variable and difficult to predict, although certain patient characteristics and biomarkers are associated with disease progression. It is important to monitor patients with SSc-ILD for signs of disease progression, although there is no consensus about which diagnostic tools to use or how often monitoring should occur. In this article, we review methods used to define and predict disease progression in SSc-ILD.

There is no valid definition of SSc-ILD disease progression, but we suggest that either a decline in forced vital capacity (FVC) from baseline of ≥10%, or a decline in FVC of 5–9% in association with a decline in diffusing capacity of the lung for carbon monoxide of ≥15% represents progression. An increase in the radiographic extent of ILD on HRCT imaging would also signify progression. A time period of 1–2 years is generally used for this definition, but a decline over a longer time period may also reflect clinically relevant disease progression.

Lung function tests and chest imaging help predict who has SSc-associated ILD and whether it will progress. In the absence of standardised methods for doctors, we recommend a strategy that combines both lung function tests and chest imaging.http://bit.ly/2uK9ZD2

Prevalence and diagnostic value of nail fold capillary microscopy in hereditary hemorrhagic telangiectasia: A retrospective study

Abnormal vasculature is a key feature of hereditary hemorrhagic telangiectasia (HHT) and can also present in the nail fold capillary beds. However, the exact prevalence and the clinical diagnostic value in HHT are still largely unknown. The nail fold can be easily and noninvasively inspected with a capillary microscope. We therefore retrospectively assessed the prevalence and diagnostic value of abnormal nail fold capillaries in all patients who were screened between January 2000 and July 2017 for the presence of HHT and underwent capillary microscopy in St Antonius Hospital, The Netherlands. Capillary microscopy results and clinical characteristics were extracted from medical files and the prevalence of abnormal nail fold capillaries was calculated and the diagnostic value of the Curaçao criteria with and without capillary microscopy results was assessed. Of the 1761 individuals screened, 923 (52%) were diagnosed with a clinical and/or genetic HHT diagnosis. In these patients, capillary microscopy was normal in 23% (n = 218), enlarged loops were seen in 11% (n = 99), and giant loops in 66% (n = 606). The sensitivity and specificity of the Curaçao criteria for the diagnosis of HHT without capillary microscopy results were 96% and 90%, respectively. The addition of the presence of giant loops to the Curaçao criteria led to a small increase in sensitivity to 97% without affecting the specificity. In conclusion, the prevalence of nail fold abnormalities in patients with HHT is high. Capillary microscopy can be a useful, easy, and noninvasive diagnostic tool in HHT.

Microcirculatory assessment of vascular diseases

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 identified to precede macrovascular involvement in the presence of cardiovascular risk factors and is the hallmark of terminal disease stages like critical limb or acral ischemia. Nevertheless, despite its obvious significance in vascular medicine assessment of microvascular function became increasingly neglected in the clinical institutions during the last decades and seems to play a subordinary role in medical education. We therefore provide an overview over relevant and clinically practicable methods to assess microcirculation in vascular medicine with critical estimations of their pros and cons and their perspectives in the future.

Pathophysiology of systemic sclerosis: current understanding and new insights

Introduction: Systemic sclerosis (SSc) is a complex autoimmune connective tissue disease characterized by chronic and progressive tissue and organ fibrosis with broad patient-to-patient variability. Some risk factors are known and include combination of persistent Raynaud's phenomenon, steroid hormone imbalance, selected chemicals, thermal, or other injuries. Endogenous and/or exogenous environmental trigger/risk factors promote epigenetic mechanisms in genetically primed subjects. Disease pathogenesis presents early microvascular changes with endothelial cell dysfunction, followed by the activation of mechanisms promoting their transition into myofibroblasts. A complex autoimmune response, involving innate and adaptive immunity with specific/functional autoantibody production, characterizes the disease. Progressive fibrosis and ischemia involve skin and visceral organs resulting in their irreversible damage/failure. Progenitor circulating cells (monocytes, fibrocytes), together with growth factors and cytokines participate in disease diffusion and evolution. Epigenetic, vascular and immunologic mechanisms implicated in systemic fibrosis, represent major targets for incoming disease modifying therapeutic approaches. Areas covered: This review discusses current understanding and new insights of SSc pathogenesis, through an overview of the most relevant advancements to present aspects and mechanisms involved in disease pathogenesis. Expert opinion: Considering SSc intricacy/heterogeneity, early combination therapy with vasodilators, immunosuppressive and antifibrotic drugs should successfully downregulate the disease progression, especially if started from the beginning.

Imbalanced serum levels of Ang1, Ang2 and VEGF in systemic sclerosis: Integrated effects on microvascular reactivity

INTRODUCTION AND AIM

Microangiopathy is a hallmark of systemic sclerosis (SSc). It is a progressive process from an early inflammatory and proangiogenic environment to insufficient microvascular repair with loss of microvessels. The exact underlying mechanisms remain ill-defined. Aim of the study was to investigate whether imbalanced angiopoietins/VEGF serum profile should be related in SSc to the altered microvascular reactivity characterized by aberrant angiogenesis and avascularity.

MATERIALS AND METHODS

Serum levels of Angiopoietin-1 (Ang1), Angiopoietin-2 (Ang2) and VEGF were measured by ELISA in 47 SSc patients and 27 healthy controls. Microvascular alterations were assessed by nailfold videocapillaroscopy (NVC).

RESULTS

Serum concentrations of Ang1 were significantly lower [mean (S.D.): 21516.04 (11,441.035) pg/ml], and Ang2 significantly increased [25,89.55 (934.225) pg/ml] in SSc as compared with the control group [Ang1: 28,457.08 (10,431.905) pg/ml; Ang2: 1556.23 (481.255) pg/ml, p < 0.01, respectively], whereas VEGF did not differ significantly. The ratios of Ang1/Ang2 and Ang1/VEGF were significantly lower in SSc patients (8.346 ± 4.523 and 95.17 ± 75.0, respectively) than in healthy subjects (17.612 ± 6.731 p < 0.000001 and 183.11 ± 137.73; p = 0.004]. Formation of giant capillaries with vascular leakage and collapse was associated with significant increase in VEGF and concomitant Ang1 deficiency. Capillary loss was related to significant increase in VEGF with respect to those with preserved capillary number (395.12 ± 256.27 pg/mL vs. 254.80 ± 213.61 pg/mL) whereas elevated Ang2 levels induced more advanced capillary damage as indicated by the presence of the "Late" NVC pattern.

CONCLUSIONS

We found that serum levels of Ang1, Ang2 and VEGF are differentially expressed in SSc and altered Ang1/Ang2 profile might underlay the aberrant angiogenesis in SSc despite increase in VEGF. For the first time we identified that significant deficiency of Ang1 might be involved in early capillary enlargement, followed by collapse and lack of stable newly-formed vessels in VEGF-enriched environment, whereas Ang2 levels seem to increase later in disease progression and advanced microvascular damage ("Late" NVC pattern).

Automated assessment of absolute nailfold capillary number on videocapillaroscopic images: Proof of principle and validation in systemic sclerosis

BACKGROUND

Absolute nailfold capillary number should be a putative biomarker in selected rheumatic diseases but could be time-consuming and not highly repeatable.

OBJECTIVE

To validate an automated software for absolute nailfold capillary number and density evaluation, on NVC images in SSc.

METHODS

An automated software to count nailfold capillary number (AUTOCAPI) had been constructed, through an exploratory image set. Subsequently, application rules have been created to define the ROI in NVC images, through a training images set. The software reliability was assessed through calculation of the ICC between automatic and manual counting, by four independent observers, on the same NVC images.

RESULTS

The following ICC's were obtained per observer, for the patients with SSc (40 images), the healthy (20 images), and the PRP subgroups (20 images), respectively: 0.94, 0.81, and 0.62 (observer 1); 0.94, 0.91, and 0.67 (observer 2); 0.88, 0.56, and 0.64 (observer 3); and 0.88, 0.85, and 0.85 (observer 4).

CONCLUSIONS

The validation of an automated software for measuring absolute nailfold capillary number and density in SSc was achieved. The integration into the pre-existing imaging software should make the assessment of the capillary number in NVC easier, quicker, and standardized.

Prospective evaluation of the capillaroscopic skin ulcer risk index in systemic sclerosis patients in clinical practice: a longitudinal, multicentre study

Background

Nailfold capillaroscopy (NC) is an important tool for the diagnosis of systemic sclerosis (SSc). The capillaroscopic skin ulcer risk index (CSURI) was suggested to identify patients at risk of developing digital ulcers (DUs). This study aims to assess the reliability of the CSURI across assessors, the CSURI change during follow-up and the value of the CSURI in predicting new DUs.

Methods

This multicentre, longitudinal study included SSc patients with a history of DUs. NC images of all eight fingers were obtained at baseline and follow-up and were separately analysed by two trained assessors.

Results

Sixty-one patients were included (median observation time 1.0 year). In about 40% of patients (assessor 1, n = 24, 39%; assessor 2, n = 26, 43%) no megacapillary was detected in any of the baseline or follow-up images; hence the CSURI could not be calculated.

In those 34 patients in whom CSURI scores were available from both assessors (26% male; median age 57 years) the median baseline CSURI was 5.3 according to assessor 1 (IQR 2.6–16.3), increasing to 5.9 (IQR 1.3–12.0) at follow-up. According to assessor 2, the CSURI diminished from 6.4 (IQR 2.4–12.5) to 5.0 (IQR 1.7–10.0).

The ability of a CSURI ≥ 2.96 category to predict new DUs was low (for both assessors, positive predictive value 38% and negative predictive value 50%) and the inter-assessor agreements for CSURI categories were fair to moderate.

Conclusions

In this study, around 40% of patients could not be evaluated with the CSURI due to the absence of megacapillaries. Clinical decisions based on the CSURI should be made with caution.

Trial registration

Current Controlled Trials, ISRCTN04371709. Registered on 18 March 2011.

Electronic supplementary material

The online version of this article (10.1186/s13075-018-1733-6) contains supplementary material, which is available to authorized users.

Evaluation of capillary pathologies by nailfold capillaroscopy in patients with psoriasis vulgaris: study protocol for a prospective, controlled exploratory study

INTRODUCTION

Psoriasis vulgaris was shown to be an independent factor increasing the risk of several comorbidities such as obesity, diabetes and dyslipidaemia with an increased risk of stroke and myocardial infarction. We hypothesise that early endothelial dysfunction, which plays a crucial role in the pathogenesis of atherosclerosis, may be detected by digital video nailfold capillaroscopy (DVNC) at the level of the dermal capillary microvasculature as a surrogate parameter. Nailfolds represent the only body site allowing for a non-invasive assessment of the capillary microvasculature at a horizontal plane. DVNC is a well-established diagnostic tool for in vivo assessment of the peripheral microcirculation by evaluating the morphology of dermal papillary capillaries. To date, reports on morphological changes of the non-lesional nailfold capillaries in patients with psoriasis vulgaris are scarce and the existing data are not conclusive.

METHODS AND ANALYSIS

This is a prospective, single-centre, non-randomised, controlled, exploratory study assessing the capillary patterns in 100 subjects affected by psoriasis vulgaris. Non-lesional nailfold capillaries will be imaged by means of DVNC (Optilia Digital Capillaroscopy System, Optilia Instruments AB, Sollentuna, Sweden) in 50 patients affected by psoriasis vulgaris and 50 healthy controls. Assessments will include a qualitative, descriptive analysis of the nailfold capillaries' morphology, as well as a quantitative investigation (frequency, extent) of changes in capillary patterns. Moreover, patients' characteristics associated with the manifestation of nailfold capillaries' pathologies including well-known cardiovascular risk markers will be studied.

ETHICS AND DISSEMINATION

Ethical approval was provided by the ethic committee of the medical faculty of the University of Heidelberg (Ethics approval number S-447/2017). The design and the final results of the study will be published and made available to the public.

TRIAL REGISTRATION NUMBER

DRKS00012856.

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 (A_Z) 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) ± SE: 15.0 ± 0.71, 12.7 ± 0.74 and 11.8 ± 0.23 for SSc, PRP and HC respectively. Combining the five structural measurements gave better classification (A_Z = 0.919 ± 0.026) than the best single measurement (mean width, A_Z = 0.874 ± 0.043), whilst adding flow further improved classification (A_Z = 0.930 ± 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.

Imaging the Microcirculation

This special issue includes the abstracts from, and three reviews by invited speakers at, the British Microcirculation Society's Annual Meeting in 2015. The reviews cover topics from the meeting symposium of "Imaging the Microcirculation" and discuss noninvasive methods of visualizing and measuring the microvasculature's structure and function.

Nailfold capillaroscopic changes in patients with idiopathic pulmonary arterial hypertension and systemic sclerosis-related pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) represents one of the main clinical expressions of the vascular changes in systemic sclerosis (SSc). Lung microvascular changes can play a role in the pathogenesis of idiopathic PAH (IPAH) also. The aim of this study is to investigate the presence of capillaroscopic abnormalities in patients with IPAH and to evaluate the differences in capillary nailfold changes between patients with IPAH and patients with SSc with and without PAH.

METHODS

39 SSc patients (19 with PAH - SSc-PAH and 20 without - SSc-noPAH), 21 subjects with IPAH and 20 healthy subjects were recruited. PAH was diagnosed by right heart catheterization. Nailfold videocapillaroscopy was performed (NVC) in all recruited subjects; capillary quantitative parameters (loops length and width, capillary density, neoangiogenesis) were evaluated and a semiquantitative scoring was used (normal, minor or major abnormalities for healthy controls and IPAH subjects and specific patterns - early, active and late - for SSc subjects) to define microvascular alterations.

RESULTS

The presence of capillaroscopic abnormalities was detected in 38,1% subjects with IPAH; particularly, compared to healthy controls, capillary density was significantly lower (7,5±1,65loops/mm vs 9±1,37loops/mm p<0,05) and mean capillary width was significantly higher (21±13μm vs 17±3μm p<0,05). A more severe NVC pattern (active/late) was described. SSc-PAH patients compared to SSc-noPAH patients (73,2% vs 50% respectively, p<0,05), with a significantly lower capillary density (5,64±1,9loops/mm vs 6,5±1,3loops/mm p<0,05) and a significantly higher capillary width (55±7μm vs 35±8μm - p<0,05) and mean number of neoangiogenesis (N/mm) (1±0,33 vs 0,2±0,22 respectively p<0,05).

CONCLUSIONS

These data, beyond to confirm the role of microvascular damage in SSc-related PAH, support the hypothesis of systemic microvascular involvement in IPAH also, which can be detected by NVC, although further studies are needed to establish whether the changes in the systemic microcirculation are causal or consequential to PAH.

Disturbed microcirculation in the hands of patients with systemic sclerosis detected by fluorescence optical imaging: a pilot study

BACKGROUND

Utilising fluorescence optical imaging (FOI), the distribution of an intravenously applied colouring agent indocyanine green (ICG) can be analysed with the potential to identify malperfusion by little to no tissue enhancement. Systemic sclerosis (SSc) is characterised by the presence of digital ulcers reflecting progressive vasculopathy. The objective was to investigate the potential of FOI in the detection of disturbed microcirculation in the hands and fingers of patients with SSc and to link FOI findings to clinical signs of ischemia such as digital ulcers and pitting scars.

METHODS

In this cross-sectional study, 63 patients with SSc and 26 healthy subjects were examined. FOI was performed in all 89 individuals and compared to clinical data and capillaroscopic findings assembled for the SSc cohort.

RESULTS

Healthy subjects showed initial ICG signals in their fingertips in 93.6%, SSc patients in 78.5% (limited SSc) and 43.2% (diffuse SSc). Moreover, in SSc patients, FOI findings were significantly associated with a late capillaroscopic pattern, disseminated SSc features, a diffuse SSc subtype, and the presence of digital ulcers or pitting scars. Intra- and inter-reader reliability for FOI amounted to κ = 0.786 and κ = 0.834, respectively.

CONCLUSIONS

FOI is able to detect areas of reduced microcirculation in patients with SSc with high association to capillaroscopic findings. The results pave the way for future FOI investigations into its role in the prediction of complications due to an impaired acral perfusion.