Abstract
We investigated platelet function and blood coagulability under the administration of antiplatelet drugs (Dypiridamole, Ticlopidine), and examined how is the better method of antithrombogenic therapy at early period after operation. Both PT and platelet aggregation were already fairly recovered at 3 days after surgery, and then showed the significant increase. Therefor antithrombogenic therapy by anti-platelet drug should be started as soon as possible after operation.