Nonstress delayed-enhancement magnetic resonance imaging of the myocardium predicts improvement of function after revascularization for chronic ischemic heart disease with left ventricular dysfunction

Background The extent of myocardial scarring of the left ventricle (LV) is important in patients with chronic ischemic heart disease (CIHD). With delayed-enhancement magnetic resonance imaging (DE-MRI), scarred myocardium (hyper-enhanced) is easily distinguishable from viable (dark) myocardium. This investigation assessed the use of DE-MRI for predicting functional improvement after coronary artery bypass grafting (CABG) in patients with CIHD and significant LV dysfunction. Methods The patient population (n = 29) with CIHD and LV dysfunction (ejection fraction 28% ± 10%) underwent both DE-MRI, to delineate scarred regions before revascularization, and echocardiography (Echo), to assess segmental function before and after CABG (interval 188 ± 57 days). Using a 16-segment model, LV myocardium was semiquantitatively analyzed for scarring based on DE-MRI and for improvements in resting function by pre- and post-CABG Echo. Results Before CABG, 82% of targeted myocardial segments had abnormal contraction; 78% showed scarring, including 38% with greater than mild amounts (25%–100%). Normal contraction was found in 18% of segments before revascularization; scarred areas were identified in 42%, 84% of which had, at most, minimal amounts (0%–24%). Of segments with pre-CABG dysfunction, 82% with no evidence of scar recovered, compared to only 18% with ≥50% scarring. Amount of hyper-enhancement was a very good indicator of improvement of function, especially at the ≥50%/segment threshold; overall accuracy was 0.74 (95% CI 0.66–0.82, P < .001). Conclusions In patients with CIHD and significant LV dysfunction, DE-MRI can predict likelihood of functional improvement after revascularization.