PROGNOSTIC-SIGNIFICANCE OF PEAK EXERCISE CAPACITY IN PATIENTS WITH CORONARY-ARTERY DISEASE

Objectives. The aim of this study was to investigate the prognostic significance of peak oxygen uptake in patients with coronary artery disease who had an exercise test that could be sustained to exhaustion without limiting symptoms. Background. Many studies have reported an inverse association between the level of exercise reached during a stress test and mortality or cardiovascular morbidity. These studies have used submaximal or symptom-limited exercise testing in patients with a recent myocardial infarction. Methods. Peak oxygen uptake was measured in male patients greater than or equal to 4 weeks after myocardial infarction (312 patients) or coronary artery surgery (215 patients) by use of a graded uninterrupted exercise test performed to exhaustion. Apart from peak oxygen uptake, several risk factors for cardiovascular disease, patient and exercise characteristics and drug treatment were considered in the Cox proportional hazards model. Results. During the total follow-up period of 3,213 patient-years, 53 patients died. Of these 53 patients, 33 died of cardiovascular causes. All-cause and cardiovascular mortality decreased with increasing peak oxygen uptake, even after adjustment for significant covariates. The relative hazard rates of 0.43 and 0.29 indicate that a hypothetic increase in peak oxygen uptake by 1 liter/min could be associated with decreases in all-cause and cardiovascular mortality of 57% and 71%, respectively. Conclusions. Exercise capacity is an independent predictor for subsequent all-cause and cardiovascular mortality in patients able to perform an exercise test until exhaustion.