Nailfold videocapillaroscopy in primary Sjögren's syndrome

Nailfold videocapillaroscopy was performed in 2 groups of subjects: 14 healthy volunteers (C) and 15 patients with primary Sjögren's syndrome (PSS). This was a controlled clinical trial, matched by age and sex. The aims of this study were to evaluate (1) functional capillary density (number of capillaries with flowing red blood cells per mm(2), FCD); (2) capillary red blood cell velocity at rest (RBV), maximum capillary red blood cell velocity (RBV(max)) after 1 minute ischemia, and the time to reach it (TRBV(max)), taking into account the presence or absence of Raynaud's phenomenon (RP) in the analysis; (3) nailfold capillary morphology; and (4) afferent (AFD), apical (APD), and efferent (EFD) capillary diameters. The mean values obtained for controls versus patients, respectively, were (mean +/- SD): FCD (per mm(2)) 8.0 +/-1.6 and 10.1 +/-3.6; RBV (mm/s) 0.9 +/-0.4 and 0.7 +/-0.2; RBV(max) (mm/s) 1.7 +/-0.9 and 1.3 +/-0.3; TRBV(max) (s) 4.5 +/-0.8 and 5.8 +/-1.6 (p=0.02); and TRBV(max) (s) in patients with RP=6.7 +/-1.6 and without RP=5.6 +/-1.6 (p=0.52). The correlation between RBV and RBV(max) for each group, using the Pearson's coefficient, was significant only for the control group (p=0.007), estimated correlation coefficient = 0.68. Controls and patients showed, in the majority of fields examined, normal morphologic patterns of capillaries. The capillary diameters were AFD (mum) 10.8 +/-1.5 and 11.3 +/-1.8; APD (mum) 16.3 +/-2.4 and 16.8 +/-2.9; and EFD (mum) 12.3 +/-1.4 and 13.7 +/-1.9. These results indicate that these patients have longer time to reach RBV(max), suggesting an impairment of the reactive hyperemia response, which could correlate with clinical features of the disease, ie, abnormal macrovascular and microvascular reactivity.