Characterization of von Willebrand factor in primary pulmonary hypertension.

The aim of this study was to determine the value of von Willebrand factor (vWF), a well-characterized endothelial cell protein secretion, as a marker for prognosis in patients with primary pulmonary hypertension (PPH). Venous and arterial blood samples were obtained from 18 clinically diagnosed PPH patients and 12 case controls matched for age and sex. Plasma vWF antigen was determined by enzyme-linked immunosorbent assay (ELISA). The patients' multimeric vWF pattern was analyzed by sodium dodecylsulfate (SDS)-agarose-acrylamide electrophoresis, Western blot, and densitometric analysis. vWF sialic acid content was determined by a lectin-based ELISA. The PPH patients showed a higher content of vWF antigen in venous (P = 0.0026) and arterial (P = 0.0094) blood samples than controls. The mean vWF sialic acid content of the PPH patients corresponded to 37.7% of the mean value for the control group. On the basis of the hemodynamic response to vasodilator trial, the PPH patients were grouped as responders or nonresponders. The latter group showed a significantly higher plasma vWF antigen antecubital vein/radial artery ratio, an increased number of unusually large vWF multimers, and a diminished content of vWF sialic acid in comparison with the first group. We believe that our results establish the nature of vWF alterations that are related to endothelial cell damage in patients with primary pulmonary hypertension and that this could be of value when establishing the prognosis in this group of patients.