Inverse relation between plasma concentration of von Willebrand factor and CrEDTA clearance in systemic sclerosis

Microvascular abnormalities involving endothelial cell dysfunction occur as an early event in systemic sclerosis. We studied plasma concentrations of von Willebrand factor (vWf), a substance released from injured endothelial cells, and its relation to pulmonary and renal dysfunction.

vWf was determined by immunoelectrophoresis. Renal function was assessed by CrEDTA clearance, an accurate measure of glomerular filtration rate and pulmonary function by spirometry and carbon monoxide diffusing capacity. Pulmonary pressure was measured by Doppler cardiography.

In 22 patients with scleroderma, vWf concentrations related inversely to CrEDTA clearance. In contrast, no relationship between plasma vWf and pulmonary function was found; 9/10 patients with pulmonary hypertension and 9/12 patients with normal pulmonary pressure showed elevated levels of vWf. However in 5 patients with pulmonary hypertension without radiographic evidence of pulmonary fibrosis there was a strong correlation between plasma vWf and pulmonary pressure (rho = 0.90) which fell short of statistical significance due most likely to small population size.

Renal but not pulmonary dysfunction was associated with elevated plasma levels of vWf.