Prevention of Recurrences of Myocardial Infarction

It is now generally accepted that the potency of any therapeutic regimen can be determined best by means of a controlled medical trial in which alternative treatments are allocated at random.¹,²Unfortunately, past medical trials conducted to test the effectiveness of long-term anticoagulant therapy in preventing recurrences of myocardial infarction have been designed so poorly that they do not qualify as controlled medical trials. The many deficiencies of these previous studies have been pointed out by others.³,⁴Under the circumstances it is not surprising to find a diversity of opinions ranging from unqualified optimism to unguarded pessimism on the role of anticoagulant agents in the long-term management of patients with myocardial infarction. In the present study the effectiveness of anticoagulant prophylaxis was assessed from observations made over a period of five years in homogeneous groups of patients free of complicating cardiovascular and systemic disease. Alternate treatment regimens of