Capillaroscopy

Abstract

Nailfold videocapillaroscopy (NVC) is a noninvasive imaging technique that is used for the in vivo assessment of the microcirculation. Its principal role in rheumatology and dermatology is to differentiate the primary and secondary forms of Raynaud’s phenomenon (RP) associated with connective tissue disease, including a predictive value for clinical complications (i.e., digital in systemic sclerosis [SSc]). The morphologic changes that characterize the microvasculature in the scleroderma-spectrum diseases at the level of the nailfold include giant capillaries, microhemorrhages, loss of capillaries, angiogenesis, and avascular areas. These alterations have been recently reclassified in SSc into three defined and different NVC patterns: (1) “early pattern” (few giant capillaries, few capillary microhemorrhages, no evident loss of capillaries, and relatively well-preserved capillary distribution), (2) “active pattern” (frequent giant capillaries, frequent capillary microhemorrhages, moderate loss of capillaries, absence or mild ramified capillaries with mild disorganization of the capillary architecture), and (3) “late pattern” (almost absent giant capillaries and microhemorrhages, severe loss of capillaries with extensive avascular areas, ramified/bushy capillaries, and intense disorganization of the normal capillary array). SSc microangiopathy correlates with disease subsets and the severity of peripheral vascular, skin, and lung involvement; in particular, patients with the “late” pattern show an increased risk to have active disease and have moderate/severe skin or visceral involvement compared to patients with “early” and “active” patterns. Skin ulcers are a common vascular complication of SSc and seem now recognized in association with rapidly progressive capillary loss and the “late” NVC pattern. NVC is considered fundamental for differentiating between primary and secondary RP, therefore making possible the early diagnosis of SSc. The validated scoring of the NVC markers of the scleroderma patterns is supported for follow-up of SSc patients. The prognostic and predictive value of capillary density is becoming an index of outcome in patients affected by SSc.