Nailfold Videocapillaroscopy in Systemic Sclerosis-related Pulmonary Arterial Hypertension: A Systematic Literature Review

Objective. Pulmonary arterial hypertension (PAH) is one of the leading causes of death in systemic sclerosis (SSc). Current screening algorithms are hampered by low positive predictive values. Outcome measures that could add to performance characteristics would be welcome. We aim to evaluate the role of nailfold videocapillaroscopy (NVC) using standardized definitions, in SSc-related PAH (SSc-PAH). Methods. A systematic review to identify original research papers documenting an association between NVC and right heart catheterization-defined SSc-PAH was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Subsequently, NVC characteristics were subdivided into quantitative (capillary density, dimension, morphology, and hemorrhages), semiquantitative, and qualitative assessment (NVC pattern), according to the definitions of the European League Against Rheumatism Study Group on Microcirculation in Rheumatic Diseases. Results. The systematic search identified 316 unique search results, of which 5 were included in the final qualitative analysis. The occurrence of incident SSc-PAH unequivocally associated in 2 longitudinal studies with progressive capillary loss (p = 0.04 and p = 0.033) and the progression to a severe (active/late) NVC pattern (p = 0.05/0.01 and HR = 5.12, 95% CI 1.23-21.27). In 3 cross-sectional studies, SSc-PAH was found to be unequivocally inversely associated with capillary density (p = 0.001 and p < 0.05) and associated with the presence of a severe NVC pattern (p = 0.03 and p < 0.05). Conclusion. This is the first systematic literature review investigating the role of NVC in SSc-PAH using standardized description, to our knowledge. Unequivocal associations were found between (incident) SSc-PAH and capillary density and NVC pattern. Integration of NVC into current screening algorithms to boost their performance may be a future step.