RATIONALE FOR ANTITHROMBOSIS THERAPY: Introducing a foreign body into the coronaries raises the risk of thrombosis in the acute phase and for the 4 following weeks. The objective of antithrombotic therapy is to inhibit platelet adhesion and aggregation or to induce hypocoagulability. AT IMPLANTATION: High-dose heparin is given in a bolus following pretreatment with aspirin. ASPIRIN-TICLOPIDINE COMBINATION: The risk of subacute thrombosis is low, about 1%, and the rate of vascular complications is minimal. Treatment is simple and compatible with short hospitalization.