Quantitation of microcirculatory abnormalities in patients with primary Raynaud's phenomenon and systemic sclerosis by video capillaroscopy

Objective. To assess nailfold capillary density and dimensions in patients with primary Raynaud's phenomenon (PRP), limited cutaneous systemic scleros is (LSSc) and diffuse cutaneous SSc (DSSc), and healthy control subjects. Methods. Using the technique of nailfold video capillaroscopy, capillary de nsity and dimensions were averaged from all visible capillaries in a 3 mm l ength of the nailfold from right and left ring fingers of each subject. Twe nty healthy control subjects, 15 patients with PRP, 13 patients with DSSc a nd 21 patients with LSSc were examined. Intra-observer and inter-observer v ariability were calculated in 18 and 23 patients, respectively. Results. There were significant trends for capillary density to fall and fo r all dimensions to rise across the four groups (P < 0.0001 for density and all dimensions, order healthy controls, PRP, DSSc and LSSc). Intra- and in ter-observer reproducibility studies showed that although there was good co rrelation between and within observers, the limits of agreement were betwee n +/-25-50% indicating lack of reproducibility. Conclusions. Microcirculatory abnormalities can be quantified using the tec hnique of video capillaroscopy and were most marked in patients with LSSc.