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 >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=<0.05 to <0.001). Interestingly, controls showed stable NVC non-specific abnormalities over the study follow-up. The number of >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’.