Assessment of short-anticoagulant administration after cardiac infarction. Report of the Working Party on Anticoagulant Therapy in Coronary Thrombosis to the Medical Research Council.

This report describes the design and results of a controlled trial of anticoagulant drugs in the treatment of patients admitted to hospital suffering from acute myocardial infarction. A total of 1,427 patients were allocated at random to therapy with high-dosage or low-dosage anticoagulants. The high-dosage regimen was 36 hours of heparin administration and phenindione in doses to maintain the thrombotest level between 10 and 20%. The mean phenindione dosage was 72 mg./day. The low-dosage regimen consisted of 1-mg. tablets of phenindione. Therapy was continued for 28 days.There was no significant reduction in the mortality in the high-dosage group. Among the 712 patients allocated to high dosage 115 (16.2%) died before the 29th day of the trial. Of the 715 patients allocated to low dosage 129 (18%) died. This difference between these mortality rates could have occurred by chance.There was a significant reduction in the frequency of clinically evident thromboembolic complications (systemic artery occlusion, leg vein thrombosis, and pulmonary embolism) among patients in the high-dosage group. This did not, however, materially affect the difference in mortality from all causes.