Platelet survival and function in animals with prosthetic mitral valve: the effect of nafazatrom

Thromboembolism remains a serious problem in patients with prosthetic heart valves. Previous studies documented a number of platelet abnormalities in such patients and correlated the occurrence of thromboembolic complications with short platelet survival. We have studied platelet survival and platelet aggregation in eight goats fitted with prosthetic mitral valves and repeated the studies following treatment with nafazatrom, a potent antithrombotic agent. Eleven survival studies in eight animals showed a platelet survival not significantly different from control (6.52 +/- 0.72 vs. 6.94 +/- 0.81 days). Following seven to ten days of oral drug administration, platelet survival in the test animals was 7.34 +/- 0.96 days, significantly longer than pretreatment results (p less than 0.01). Animals with the shortest pretreatment platelet survival achieved substantial prolongation of platelet life span following drug treatment. The drug caused no change in ex vivo platelet aggregation.