BACKGROUND: Predicting the risk of cardiac and all-cause death in patients with established coronary heart disease is important in counseling the individual and designing risk-stratified rehabilitation and secondary prevention programs. Cox proportional hazards and Kaplan-Meier survival curves were thus completed on initial assessment data obtained from patients referred to an outpatient cardiac rehabilitation center.
METHODS AND RESULTS: A single-center prospective observational design took peak cardiorespiratory exercise test data for 12 169 male rehabilitation candidates aged 55.0+/-9.6 years (7096 myocardial infarctions [MIs], 3077 coronary artery bypass grafts [CABGs], and 1996 documented cases of ischemic heart disease [IHD]). A follow-up of 4 to 29 years (median, 7.9) yielded 107 698 man-years of experience. Entry data were tested for associations with time to cardiac and all-cause death. We recorded 1336 cardiac deaths (953 MI, 225 CABG, and 158 IHD) and 2352 all-cause deaths. A powerful predictor of cardiac and all-cause mortality was measured peak oxygen intake (VO2peak). For the overall sample, values of <15, 15 to 22, and >22 mL/kg per minute yielded respective multivariate adjusted hazard ratios of 1.00, 0.62, and 0.39 for cardiac and 1.00, 0.66, and 0.45 for all-cause deaths. For the separate diagnostic categories, apart from VO2peak, the only other significant predictors of cardiac death common to all 3 were smoking and digoxin, and for all-cause death, age, smoking, digoxin, and diabetes.
CONCLUSIONS: Exercise capacity, as determined by direct measurement of VO2peak, exerts a major long-term influence on prognosis in men after MI, CABG, or IHD and can play a valuable role in risk stratification and counseling.