Prognosis of patients with a first non-Q-wave myocardial infarction before and in the reperfusion era

Abstract

Background The reported incidence of non-Q-wave acute myocardial infarction (AMI) has increased in the thrombolytic era. Data comparing prognosis among these patients before and after the advent of the thrombolytic era are scarce.Methods We compared the early and late prognosis among 2 cohorts of consecutive patients with a first non-Q-wave AMI hospitalized in the coronary care units operating in Israel: 610 patients from 1981 to 1983 and 225 patients in 1994.Results The proportion of patients with non-Q-wave AMI increased from 14% in 1981 to 1983 to 32% in 1994. Baseline characteristics in both periods were comparable. In-hospital management of patients differed during the last decade. Patients in 1994 received aspirin, angiotensin-converting enzyme inhibitors, β-blockers, and nitrates more frequently than in the period 1981 to 1983. Thrombolytic therapy, coronary angiography, and percutaneous transluminal coronary angioplasty or coronary artery bypass grafting were not used during the index hospitalization in the early 1980s, whereas in 1994 these procedures were used in 28%, 38%, 19%, and 6% of patients, respectively. In-hospital complications, including arrhythmias, conduction disturbances, and heart failure, were less frequent in 1994 compared with the period 1981 to 1983. The 7- and 30-day crude mortality rates were significantly lower in 1994 compared with the early 1980s (5% vs 9% and 5% vs 13%, respectively, P <.05 for both), whereas the 1-year crude mortality rate decreased slightly (15% vs 19%, P =.13). Multivariate analyses adjusting for pertinent variables revealed a decreased risk for death in 1994 versus 1981 to 1983; for 7-day (odds ratio = 0.49, 95% confidence interval 0.23 to 0.94), 30-day (odds ratio = 0.36, 95% confidence interval 0.18 to 0.69) and for 1-year (odds ratio = 0.65, 95% confidence interval 0.44 to 0.96).Conclusion The prognosis of patients with a first non-Q-wave AMI has improved considerably during the last decade. The introduction of new therapeutic modalities, including invasive cardiac procedures and new medications, probably played a major role in the favorable outcome of these patients. (Am Heart J 1998;136:245-51.)