Relation between exertional ischemia and prognosis in mildly symptomatic patients with single or double vessel coronary artery disease and left ventricular dysfunction at rest

Abstract

The randomized multicenter trials indicate that survival in patients with coronary artery disease and left ventricular dysfunction is enhanced by surgical therapy compared with medical therapy. This beneficial effect of coronary bypass surgery was demonstrated in patients with either three vessel or left main coronary artery disease, but not in those with one or two vessel disease. To determine whether subgroups of mildly symptomatic patients with one or two vessel coronary artery disease and left ventricular dysfunction have an increased risk of death or cardiac events during medical therapy, 53 consecutive patients with angiographically defined one or two vessel disease and impaired left ventricular function (ejection fraction 20% to 40%) were studied by exercise electrocardiography (ECG) and rest and exercise radionuclide angiography. All but two patients had previous myocardial infarction, and all were asymptomatic or only mildly symptomatic during medical therapy.By univariate life table analysis, mortality during medical therapy was associated significantly with the ST segment response to exercise (p < 0.05) and with both the exercise ejection fraction (p < 0.05) and the magnitude of change in ejection fraction with exercise (p < 0.005). In patients with an exercise ejection fraction >30%, the probability of survival at 6 years was 97 ± 3% (±SE) compared with a survival rate of 62± 14% in the remaining subjects (p < 0.005). Similarly, 6 year survival was 100% in patients whose ejection fraction increased from the value at rest but was only 74 ± 10% in the remaining patients (p < 0.005). Exercise capacity was not associated with survival. The likelihood of a cardiac event (death, reinfarction or congestive heart failure) during medical treatment was also associated significantly with the exercise ejection fraction and magnitude of change in ejection fraction with exercise (both p < 0.005). Twelve of the 18 events, including seven of the eight deaths, occurred in patients with two vessel disease.Therefore, noninvasive indexes of left ventricular function and myocardial ischemia are important predictors of the clinical course of mildly symptomatic patients with two vessel disease and left ventricular dysfunction at rest, and may be used to identify subgroups of patients at risk of death, as well as of major cardiac events, during subsequent medical therapy.