INVERSE RELATION BETWEEN PLASMA-CONCENTRATION OF VON-WILLEBRAND-FACTOR AND CREDTA CLEARANCE IN SYSTEMIC-SCLEROSIS

Objective. Microvascular abnormalities involving endothelial cell dysf unction occur as an early event in systemic sclerosis. We studied plas ma concentrations of von Willebrand factor (vWf), a substance released from injured endothelial cells, and its relation to pulmonary and ren al dysfunction. Methods. vWf was determined by immunoelectrophoresis. Renal function was assessed by CrEDTA clearance, an accurate measure o f glomerular filtration rate and pulmonary function by spirometry and carbon monoxide diffusing capacity. Pulmonary pressure was measured by Doppler cardiography. Results. In 22 patients with scleroderma, vWf c oncentrations related inversely to CrEDTA clearance. In contrast, no r elationship between plasma vWf and pulmonary function was found; 9/10 patients with pulmonary hypertension and 9/12 patients with normal pul monary pressure showed elevated levels of vWf. However in 5 patients w ith pulmonary hypertension without radiographic evidence of pulmonary fibrosis there was a strong correlation between plasma vWf and pulmona ry pressure (rho = 0.90) which fell short of statistical significance due most likely to small population size. Conclusion. Renal but not pu lmonary dysfunction was associated with elevated plasma levels of vWf.