[Epidemiology of von Willebrand's disease in the state of Zulia, Venezuela].

The prevalence of von Willebrand's disease (vWd) in Zulia State, Venezuela, was studied among patients referred because of hemorrhagic symptoms. Ninety six cases out of 684 patients aged six months to fifty years, were diagnosed as vWd by measuring FvW, FVIII and Ristocetin cofactor in plasma, along with determinations of the bleeding time and platelet aggregation with ristocetin. Crossed immune electrophoresis and determination of FvW concentration in platelets were also carried out in several patients. The prevalence of the disease in Zulia State was 42.9/10(6) inhabitants and in the metropolitan area of Maracaibo (capital city of Zulia State) was 73/10(6) inhabitants. Eighty eight per cent of the patients were classified as vWd Type I, 2% as vWd Type IIb and 4.1% as Type III. Five cases were not classified. Three patients with Type I vWd also suffered from Autoimmune Thrombocytopenic Purpura, one had a SC hemoglobinopathy and in one patient the disease coexisted with mitral valve prolapse. The need for a proper attention to the patients with vWd is emphasized, as its prevalence in the region is similar to that found in european countries, where a great effort is applied to assure the adequate therapy and social support.