RESUMEN
Twenty six adult patients who underwent prosthetic heart valve replacement and treated anti-thrombogenic therapy, were divided into 2 groups. One was administered Warfarin alone, another was administered Warfarin plus Aspirin (162mg/day) as antiplatelet therapy. Trapidil (300mg/day) was administered to all of the patients. Platelet aggregation, plasma level of TXB<sub>2</sub> (stable metabolite of thromboxane A<sub>2</sub>), and 6-keto-PGF<sub>1</sub> (stable metabolite of PGI<sub>2</sub>) were measured before and 1, 3, 6 months after Trapidil therapy. Platelet aggregability suppressed in both 2 groups. Plasma TXB<sub>2</sub> level, and TXB<sub>2</sub>/6-keto-PGF<sub>1</sub> ratio showed a tendensy to decrease (<i>p</i><0.05) 6 months after administration. In the Aspirin plus Trapidil group, platelet aggregability, serum TXB<sub>2</sub> level, and TXB<sub>2</sub>/6-keto-PGF<sub>1</sub> ratio are significantly lower than that in the Trapidil only. These results suggest that Trapidil is clinically useful for antiplatelet agent, but the combined Aspirin plus Trapidil therapy is more efficacious than the Aspirin or Trapidil single therapy.