Prognostic value of left ventricular ejection fraction response to exercise during long-term follow-up after coronary artery bypass graft surgery.

BACKGROUND

Recent data, albeit based on operations often performed more than 15 years ago, suggest that survival benefits of coronary artery bypass graft surgery (CABG) generally are lost within 10 years after operation. A reliable noninvasive method for periodic assessment of ischemia severity after operation might permit optimal timing of additional therapy to minimize loss of benefits.

METHODS AND RESULTS

To determine the impact of left ventricular ejection fraction (LVEF) during exercise on prognosis in patients who have undergone CABG, results of rest and exercise radionuclide cineangiography were correlated with mortality, major nonsurgical cardiac events, and cardiac event-free or surgery-free survival in 192 patients who underwent index radionuclide study > or = 1 month (average, 26 months) after CABG. Average follow-up after study was 8.7 years among event-free patients. Initial events during follow-up included 31 deaths, 19 nonfatal myocardial infarctions, and 33 late repeat CABG or angioplasties (PTCA). Stepwise Cox regression analysis identified change (delta) in LVEF with exercise as the strongest independent predictor of cardiac death, major nonsurgical cardiac events, and cardiac event-free or surgery-free survival (P < .0001, all outcomes). Change in heart rate with exercise, completeness of revascularization, and New York Heart Association functional class for angina provided additional independent information. With each 10% decrement in delta LVEF, the hazard of cardiac death increased more than twofold, and the hazard of major nonsurgical cardiac events considered alone or in combination with repeat CABG or PTCA increased > 1.5 times.

CONCLUSIONS

Thus, assessment of delta LVEF is prognostically useful after CABG. Assessment of this variable may help determine the need for repeat CABG. The utility of this approach now should be confirmed by longitudinal prognostic study.