Myocardial Viability by Cardiac Magnetic Resonance Imaging Before Coronary Artery Bypass Grafting

Background: The predictive value of myocardial viability assessed by cardiac magnetic resonance imaging (CMR) in patients with ischemic cardiomyopathy undergoing coronary artery bypass grafting (CABG) is uncertain. Other assessment modalities have not shown a correlation between viability and post-CABG survival. Methods: Patients from a single institution between 2014 and 2022 with ischemic cardiomyopathy who were undergoing isolated CABG and who had preoperative CMR viability assessment were included. Patients were grouped by left anterior descending artery territory viability: 0% fibrosis, 25% to 50% fibrosis, and 75% to 100% fibrosis. Primary outcomes were postoperative improvement in left ventricular ejection fraction and 3-year survival. Analyses were adjusted for The Society of Thoracic Surgeons Predicted Risk of Morbidity or Mortality scores. Results: A total of 106 patients met inclusion criteria, and they were divided into 3 groups by myocardial viability. There were no significant differences in preoperative or operative factors among the groups. Left ventricular ejection fraction improvement was seen in 60.3% of patients in the viable without fibrosis group, 79.0% of patients in the viable with fibrosis group, and 57.1% of patients in the nonviable group. Adjusted odds ratios of ejection fraction improvement among the groups demonstrated no significant differences. Similarly, there were no differences in patient survival by 3 years after CABG on Kaplan-Meier analysis. Conclusions: Myocardial viability assessment by CMR for patients with ischemic cardiomyopathy who are undergoing surgical revascularization does not predict left ventricular functional improvement or 3-year survival. Our data suggest that nonviable left anterior descending artery territory as assessed by CMR should not be a contraindication to CABG in otherwise appropriate surgical candidates.