Long-term prognosis of clinical variables, coronary reserve and extent of coronary disease in patients with a first episode of unstable angina.

Clinical and ECG prognostic markers, ischemic threshold (IT) and extent of coronary disease were analyzed in 383 patients with unstable angina (UA) and correlated with long-term events. Patients >74 years or those with severe heart failure or previous revascularization procedures were excluded. There were 369 events in 245 patients: 87 deaths, 96 myocardial infarction (MI), 111 coronary artery bypass grafting (CABG), and 75 angioplasty procedures (PTCA). Follow-up was obtained in 367 hospital survivors (99%, 114 (44) months) and ST depression on admission ECG, a modest enzyme rise, refractory angina (>2 episodes), two to three vessel coronary disease and a reduced IT (<==130 beats/min) were each associated with cardiac events. A multivariate analysis, however, showed refractory angina (p<0.001) and multivessel disease (p<0.001) as most significant predictors. After their exclusion, IT was most relevant predictor (p<0.001). However, the predictive value of these markers was essentially centered on first-year events (249, 67%). Moreover, refractory angina, minor enzyme rise and admission ST depression were each highly correlated with a reduced IT (p<0.006) and with multivessel disease (p<0.0001). Therefore, these findings underscore that the prognostic value of conventional clinical markers in patients with UA is limited to first-year events and that their remarkable correlation with extensive coronary disease and reduced coronary reserve reveal the anatomical substrate of this prognostic significance.