Nailfold capillaroscopy in mixed connective tissue disease, systemic sclerosis, and primary Raynaud phenomenon in a capillaroscopy service from Medellin, Colombia, 2015-2020

Introduction: Nailfold capillaroscopy is a useful tool to evaluate microcirculation. In mixed connective tissue disease (MCTD), microvascular changes are not clearly defined. Objective: This study aims to compare the angiographic findings between patients with mixed connective tissue disease, systemic sclerosis, and primary Raynaud phenomenon (pRP) in a capillaroscopy reference centre. Materials and methods: A retrospective descriptive study with an exploratory analytical component was designed. Clinical and capillaroscopic characteristic information was obtained from medical records and capillaroscopic reports from an expert capillaroscopy service using an Optilia 200× videocapillaroscope. To compare qualitative variables, the Pearson or Fisher exact chi-square test was used in case of expected frequencies lower than five. Results: One hundred and twenty capillaroscopy charts were reviewed. In the MCTD group, 42.5% of patients showed a normal pattern, 37.5% had a non-scleroderma pattern, and 20% exhibited a scleroderma pattern. Among pRP patients, 62.5% had a normal and 37.5% had a non-specific pattern; both groups preserved capillary density. In MCTS, compared to SS, there were fewer avascular areas (10% vs. 62.5%, P < .001), megacapillaries (20% vs 100%, P < .001), and haemorrhages (37.5 vs. 92.5%, P< .001). Bushy capillaries predominated in the MCTD (10%) compared to SS (5%) and pRP (0%) groups without significance difference (P = .122). Conclusions: Compared to systemic sclerosis, mixed connective tissue disease presents greater capillary density and a greater frequency of arborescent capillaries.