Background: The value of assessment of viability as a predictor of surgical revascularization benefit in ischemic cardiomyopathy has recently been questioned in a large trial. We sought to determine whether the contribution of viability as myocardial scar burden (SB) to predict revascularization outcomes could be modulated by end-systolic volume index (ESVi).
Methods and results: Delayed hyperenhancement-MRI was obtained in 450 patients with ≥70% stenosis in ≥1 epicardial coronary artery (75% men; median age, 62.8 ± 10.7 years; mean left ventricular ejection fraction, 23 ± 9%; mean ESVi, 115 ± 50 mL) from 2002 to 2006. SB was quantified as scar percentage (infarcted mass/total left ventricular mass). Subsequent surgical revascularization was performed in 245 (54%) patients and subsequent percutaneous coronary interventions were performed in 28 (6%) patients. A propensity score was developed for revascularization. Cox proportional hazards models of all-cause mortality were used for risk adjustment. Over a mean follow-up of 5.8 ± 2.7 years, 186 (41%) deaths occurred. After adjusting for prior revascularization, sex, diabetes, age, use of cardiac resynchronization therapy, implantable cardioverter defibrillator, mitral regurgitation, and mitral valve procedures; an interaction between scar percentage and ESVi (P=0.016) and an interaction between post-MRI revascularization and ESVi (P=0.0017) were independently associated with mortality. ESVi demonstrated a significant interaction with revascularization and female sex, such that enhanced survival was associated with ESVi. ESVi also showed an interaction with SB; better survival was associated with lower volumes and less scar.
Conclusions: ESVi and SB provide independent, incremental prognostic value in patients with severe ischemic cardiomyopathy. The risk associated with SB should not be assessed in isolation.