Myocardial viability and long-term outcomes in ischemic cardiomyopathy

BACKGROUND: The role of assessment of myocardial viability in identifying patients with ischemic cardiomyopathy who might benefit from surgical revascularization remains controversial. Furthermore, although improvement in left ventricular function is one of the goals of revascularization, its relationship to subsequent outcomes is unclear. METHODS: Among 601 patients who had coronary artery disease that was amenable to coronaryartery bypass grafting (CABG) and who had a left ventricular ejection fraction of 35% or lower, we prospectively assessed myocardial viability using single-photonemission computed tomography, dobutamine echocardiography, or both. Patients were randomly assigned to undergo CABG and receive medical therapy or to receive medical therapy alone. Left ventricular ejection fraction was measured at baseline and after 4 months of follow-up in 318 patients. The primary end point was death from any cause. The median duration of follow-up was 10.4 years. RESULTS: CABG plus medical therapy was associated with a lower incidence of death from any cause than medical therapy alone (182 deaths among 298 patients in the CABG group vs. 209 deaths among 303 patients in the medical-therapy group; adjusted hazard ratio, 0.73; 95% confidence interval, 0.60 to 0.90). However, no significant interaction was observed between the presence or absence of myocardial viability and the beneficial effect of CABG plus medical therapy over medical therapy alone (P=0.34 for interaction). An increase in left ventricular ejection fraction was observed only among patients with myocardial viability, irrespective of treatment assignment. There was no association between changes in left ventricular ejection fraction and subsequent death. CONCLUSIONS: The findings of this study do not support the concept that myocardial viability is associated with a long-term benefit of CABG in patients with ischemic cardiomyopathy. The presence of viable myocardium was associated with improvement in left ventricular systolic function, irrespective of treatment, but such improvement was not related to long-term survival. (Funded by the National Institutes of Health; STICH ClinicalTrials.gov number, NCT00023595.). (AU)

Myocardial viability and survival in ischemic left ventricular dysfunction

Background The assessment of myocardial viability has been used to identify patients withcoronary artery disease and left ventricular dysfunction in whom coronary-arterybypass grafting (CABG) will provide a survival benefit. However, the efficacy of thisapproach is uncertain. Methods In a substudy of patients with coronary artery disease and left ventricular dysfunctionwho were enrolled in a randomized trial of medical therapy with or withoutCABG, we used single-photon-emission computed tomography (SPECT), dobutamineechocardiography, or both to assess myocardial viability on the basis of prespecifiedthresholds.ResultsAmong the 1212 patients enrolled in the randomized trial, 601 underwent assessmentof myocardial viability. Of these patients, we randomly assigned 298 to receivemedical therapy plus CABG and 303 to receive medical therapy alone. A total of 178of 487 patients with viable myocardium (37%) and 58 of 114 patients without viablemyocardium (51%) died (hazard ratio for death among patients with viable myocardium,0.64; 95% confidence interval [CI], 0.48 to 0.86; P = 0.003). However, afteradjustment for other baseline variables, this association with mortality was notsignificant (P = 0.21). There was no significant interaction between viability statusand treatment assignment with respect to mortality (P = 0.53).ConclusionsThe presence of viable myocardium was associated with a greater likelihood ofsurvival in patients with coronary artery disease and left ventricular dysfunction,but this relationship was not significant after adjustment for other baseline variables.The assessment of myocardial viability did not identify patients with a differentialsurvival benefit from CABG, as compared with medical therapy alone.(Funded by the National Heart, Lung, and Blood Institute; STICH ClinicalTrials.govnumber, NCT00023595.)