Platelet aggregation induced by cryoprecipitate infusion in platelet-type von Willebrand's disease.

Platelet-type von Willebrand's disease (VWD) is a recently described bleeding disorder characterized by a heightened interaction between platelets and von Willebrand factor (vWF) as the result of an intrinsic platelet-membrane abnormality. Administration of cryoprecipitate into a patient with this disorder was followed by thrombocytopenia in vivo and "spontaneous" platelet aggregation in vitro. However, a prolonged bleeding time was shortened and sufficient haemostasis was achieved without thromboembolic complications. These results provide evidence that human vWF infused with cryoprecipitate directly interacts with platelet-type vWD platelets, causing thrombocytopenia in vivo, and suggest that impaired primary haemostasis is related to the depletion of the high-molecular-weight vWF multimers in the circulating plasma.