Impaired fibrinolytic response to DDAVP in patients with von Willebrand's disease

The fibrinolytic response after infusion of 1-deamino-8-d-arginine vasopressin (DDAVP) was examined in 4 patients with the severe form and 17 patients with the moderate form of Von Willebrand's disease (VWd) and compared to that of 9 normal subjects. Tissue plasminogen activator (t-PA) antigen (Ag) and activity and tissue plasminogen activator inhibitor (PAI) were measured before and after DDAVP. t-PA Ag was found to be significantly higher before DDAVP in patients than in controls. No release of t-PA Ag was observed in the 4 patients with the severe form of VWd but increased release was observed in patients with moderate forms. However, t-PA released into the circulation in these 17 patients had a lower functional activity as compared to that of normal subjects. PAI was significantly lower in patients before DDAVP than in normal subjects and the decrease in PAI after DDAVP was significantly less in patients than in controls. It is concluded from this study that patients with VWd have an abnormal fibrinolytic response after stimulation regardless of the severity of the disease. Furthermore, the results suggest either that patients with VWd have a double defect in VWF and tissue plasminogen activator or that the primary deficiency of VWF influences the synthesis and/or release of t-PA by endothelial cells.