Incremental value of myocardial viability for prediction of long-term prognosis in surgically revascularized patients with left ventricular dysfunction.

OBJECTIVES: We assessed the incremental long-term prognostic value of myocardial viability in surgically revascularized (CABG) patients with left ventricular (LV) dysfunction.
BACKGROUND: Clinical factors, medical therapy, the degree of LV dysfunction, and stress-induced ischemia may affect the relative prognostic value of myocardial viability.
METHODS: Patients with coronary disease and ventricular dysfunction (mean ejection fraction 33% by echocardiography, 25% by angiography) were studied with dobutamine echocardiography. Follow-up (mean -4.9 years) was obtained in 95 patients (85% triple-vessel disease) who underwent CABG.
RESULTS: The use of angiotensin-converting enzyme inhibitors, advanced heart failure, rest, low- and peak-dose wall motion scores were univariate predictors of cardiac death. The extent of contractile reserve and ischemia were not predictive. Low-dose score was the strongest multivariate predictor of death (p < 0.001, hazard ratio 6.7). A biphasic response predicted better survival (p = 0.045, hazard ratio 0.5). Five-year survival was better in those with extensive (low-dose score <2.00) versus intermediate (score 2.00 to 2.49) amounts of viable myocardium (p = 0.019). Patients with the least viability (score > or =2.5) had the worst outcome (p = 0.0001 vs. those with low-dose score <2.00; p = 0.05 vs. those with score 2.00 to 2.49). In stepwise multivariate analysis, low-dose score added incremental prognostic value (p = 0.024) to clinical information and rest score.
CONCLUSIONS: Low-dose score, representing the extent of viable myocardium, has incremental prognostic value as a predictor of long-term outcome in CABG patients with LV dysfunction.