Impact of Myocardial Viability on Long-term Outcomes After Surgical Revascularization

Background: This study was conducted to evaluate whether myocardial viability assessed with cardiac magnetic resonance affected long-term clinical outcomes after coronary artery bypass grafting (CABG) in patients with ischemic cardiomyopathy. Methods: Preoperative cardiac magnetic resonance with late gadolinium enhancement (LGE) was performed in 103 patients (64.9±10.1 years, male:female = 82:21) with 3 vessel disease and left ventricular dysfunction (ejection fraction ≤0.35). Transmural extent of LGE was evaluated on a 16-segment model, and transmurality was graded on a 5-point scale: grades 0, absence; 1, 1%-25%; 2, 26%-50%; 3, 51%-75%; 4, 76%-100%. Median follow-up duration was 65.5 months (interquartile range = 27.5-95.3 months). Primary endpoint was the composite of all-cause mortality or hospitalization for congestive heart failure. Results: Operative mortality was 1.9%. During the follow-up, all-cause mortality and readmission for congestive heart failure occurred in 29 and 8 patients, respectively. The cumulative incidence of the primary endpoint was 31.3% and 46.8% at 5 and 10 years, respectively. Multivariable analysis demonstrated that the number of segments with LGE grade 4 was a significant risk factor (hazard ratio 1.42, 95% confidence interval 1.10–1.83, P =.007) for the primary endpoint among the variables assessed by cardiac magnetic resonance. Other risk factors included age, dialysis, chronic obstructive pulmonary disease, and EuroSCORE II. Conclusions: The number of myocardial segments with transmurality of LGE >75% might be a prognostic factor associated with the composite of all-cause mortality or hospitalization for congestive heart failure after CABG in patients with 3-vessel disease and ischemic cardiomyopathy.