In a cooperative study involving 15 Veterans Administration hospitals, patients with acute myocardial infarction were divided into two groups by random selection. One group was treated with an anticoagulant, the other served as control. All of the 785 patients included in the report were followed for two years or until their death, and more than one half were followed for five years. Results indicate that anticoagulant therapy reduces the death rate significantly during the first three years after an acute myocardial infarction. However, survival rates converge after the third year, and by the fifth year there is no difference in survival of treated and untreated groups. Therapy appeared to be more effective in patients who had experienced more than one infarction. The incidence of recurrent infarction and congestive heart failure was less in the group treated with anticoagulants.
Ebert RV, Borden CW, Hipp HR, Holzman D, Lyon AF, Schnaper H. Long-Term Anticoagulant Therapy After Myocardial InfarctionFinal Report of the Veterans Administration Cooperative Study. JAMA. 1969;207(12):2263-2267. doi:10.1001/jama.1969.03150250093010