Effect of Antiplatelet and Anticoagulant Therapy on Secondary Prevention and Longterm Prognosis after Acute Myocardial Infarction in Aged Patients

Abstract

The longterm efficacy and side effects of antiplatelet and anticoagulant therapy for secondary prevention after the first acute myocardial infarction (AMI) were retrospectively assessed in 133 patients over 60 years of age during a mean follow-up period of 36.6 months. Seventy five patients received antiplatelet and anticoagulant therapy (group 1) and 58 patients did not (group 2). In group 1 patients, 54, 12 and 9 patients received ticlopidine, aspirin and warfarin, respectively. Mean age, sex ratio, site of AMI, max CPK value and left ventricular ejection fraction in the convalescent phase did not differ between the two groups. There were no differences between the two groups in terms of the number and kind of combination drugs such as nitrate, beta-blocker and Ca antagonist. During the follow-up period 40 patients died; 18 patients (45%) suffered cardiac death and 22 patients (55%) experienced noncardiac death. Nineteen patients had recurrent MI and 37 patients had cardiac events which were defined in total as cardiac death, recurrent MI and unstable angina pectoris. The total mortality rate and rate of recurrent MI based on the life time table method were significantly lower in group 1 than in group 2 by the generalized Wilcoxon test. The cumulative total mortality rate in the fifth year was 24.2% in group 1 and 49% in group 2. The cumulative rate for recurrent MI in the fifth year was 7.4% in group 1 and 27.5% in group 2 (p<0.05). However, the rate of cardiac events did not differ between the two groups. Ten patients (13%) in group 1 discontinued antiplatelet and anticoagulant therapy due to the complication such as bleeding tendency, gastrointestinal symptom and liver dysfunction. Thus, longterm antiplatelet and anticoagulant therapy was relatively safe and effective on secondary prevention for recurrent MI in aged patients with first AMI. © 1992, The Japan Geriatrics Society. All rights reserved.