May capillaroscopy be a candidate tool in future algorithms for SSC-ILD: Are we looking for the holy grail? A systematic review.

OBJECTIVE: To investigate whether nailfold videocapillaroscopy (NVC), an increasingly worldwide used non-invasive tool to reliably evaluate the peripheral microcirculation, may be an outcome measure in future screening algorithms for systemic sclerosis related interstitial lung disease (SSc-ILD). METHODS: A systematic review to identify original research papers documenting an association between NVC and SSc-ILD was performed in 3 electronic databases according to the PRISMA guidelines. Subsequently, NVC parameters were subdivided according to the consented standardised capillaroscopic definitions of the EULAR Study Group on Microcirculation in Rheumatic Diseases / Scleroderma Clinical Trials Consortium on Capillaroscopy, into quantitative (capillary density, capillary dimension, capillary morphology and haemorrhages) and qualitative assessment (NVC pattern). RESULTS: The systematic search identified 310 unique search results, of which 2 cross-sectional and 1 longitudinal study were retained. In both cross-sectional studies, the presence of SSc-ILD was found to be inversely associated with capillary density (p = .008 and p = .005). The presence of a severe (active/late) NVC pattern was evaluated and associated with the presence of SSc-ILD in one of the cross-sectional studies. In the longitudinal study, incident SSc-ILD was associated with progressive capillary loss (p = .03) and the conversion to a worse (active/late) NVC pattern (p = .001/p = .003). CONCLUSIONS: This first systematic literature review investigating the role of NVC in SSc-ILD using standardised capillaroscopic definitions uncovered associations between NVC and (incident) SSc-ILD. If large prospective studies further corroborate and elucidate these findings, NVC might possibly be a candidate outcome measure to be integrated in screening algorithms for incident/progressive SSc-ILD.

Fast track algorithm: How to differentiate a "scleroderma pattern" from a "non-scleroderma pattern".

OBJECTIVES: This study was designed to propose a simple "Fast Track algorithm" for capillaroscopists of any level of experience to differentiate "scleroderma patterns" from "non-scleroderma patterns" on capillaroscopy and to assess its inter-rater reliability. METHODS: Based on existing definitions to categorise capillaroscopic images as "scleroderma patterns" and taking into account the real life variability of capillaroscopic images described standardly according to the European League Against Rheumatism (EULAR) Study Group on Microcirculation in Rheumatic Diseases, a fast track decision tree, the "Fast Track algorithm" was created by the principal expert (VS) to facilitate swift categorisation of an image as "non-scleroderma pattern (category 1)" or "scleroderma pattern (category 2)". Mean inter-rater reliability between all raters (experts/attendees) of the 8th EULAR course on capillaroscopy in Rheumatic Diseases (Genoa, 2018) and, as external validation, of the 8th European Scleroderma Trials and Research group (EUSTAR) course on systemic sclerosis (SSc) (Nijmegen, 2019) versus the principal expert, as well as reliability between the rater pairs themselves was assessed by mean Cohen's and Light's kappa coefficients. RESULTS: Mean Cohen's kappa was 1/0.96 (95% CI 0.95-0.98) for the 6 experts/135 attendees of the 8th EULAR capillaroscopy course and 1/0.94 (95% CI 0.92-0.96) for the 3 experts/85 attendees of the 8th EUSTAR SSc course. Light's kappa was 1/0.92 at the 8th EULAR capillaroscopy course, and 1/0.87 at the 8th EUSTAR SSc course. CONCLUSION: For the first time, a clinical expert based fast track decision algorithm has been developed to differentiate a "non-scleroderma" from a "scleroderma pattern" on capillaroscopic images, demonstrating excellent reliability when applied by capillaroscopists with varying levels of expertise versus the principal expert and corroborated with external validation.