Quantitative analysis of nailfold capillary abnormalities in patients with connective tissue diseases.

BACKGROUND: Nailfold capillary microscopy has been shown to reflect microvascular disturbances mainly in connective tissue diseases including systemic sclerosis (SSc).
METHODS: Nailfold capillary abnormalities were analyzed with a light microscope under immersion oil at magnifications of x60 and x400.
RESULTS: Abnormal nailfold capillary pattern in SSc was different from that of systemic lupus erythematosus (SLE) and normal controls, but not from dermatomyositis (DM). Seventy-two per cent of patients with Raynaud's phenomenon showed an abnormal nailfold capillary pattern. In primary Raynaud's phenomenon, 12% of subjects developed undifferentiated connective tissue disease. In undifferentiated connective tissue disease, 23% developed SSc. The apical limb width, capillary width and capillary length of subjects who developed SSc were significantly larger than in those who did not. With regard to the clinicolaboratory findings, the occurrence rate of an abnormal apical limb width, abnormal capillary width, abnormal capillary length, and antinuclear antibody in patients who developed SSc was significantly higher than in those who did not. An abnormal capillary pattern correlated with an elevated pulmonary artery resistance. All the patients with pulmonary arterial hypertension showed an abnormal capillary pattern, decreased diffusion capacity for carbon monoxide, and elevated pulmonary vascular resistance. Nailfold capillary abnormalities show a close relation to pulmonary arterial hypertension.
CONCLUSIONS: Nailfold capillary abnormalities are useful for detecting vascular abnormality in clinical practice. These facts stress the importance of nailfold capillary abnormalities in SSc.