Abstract 15757: Association of Ischemic Mitral Regurgitation Proportionality With Outcomes After Mitral Valve Surgery: A Cardiothoracic Surgical Trials Network Analysis

Introduction:The severity of secondary mitral regurgitation (MR) relative to left ventricular (LV) volume might predict the clinical response to treatments directed to either the mitral valve (MV) or to the left ventricle. Whether this concept applies to MV surgery for severe ischemic MR (SIMR) is unknown.Methods:We evaluated the outcomes of patients with SIMR according to the baseline effective regurgitant orifice area (EROA)-to-LV end-diastolic volume (LVEDV) ratio (divided into tertiles) enrolled in a randomized trial comparing surgical MV replacement versus repair +/- CABG. Patients were followed for 2 years. Endpoints were all-cause mortality, major adverse cardiac and cerebrovascular events (MACCE), and the mean percent changes in LVEDV and end-systolic volume (LVESV) from baseline through 2 years assessed by an echo core-lab.Results:A total of 240 patients out of 251 randomized were included. Baseline characteristics across tertiles of EROA/LVEDV ratio are reported in the table. Compared with patients in tertile 1 (lowest ratio), those in tertile 3 (highest ratio) had higher risk of 2-year all-cause mortality (15% vs. 28.8%; adjusted HR: 2.98; 95% CI: 1.38-6.47) and MACCE (40% vs. 47.5%; adjusted HR: 1.95; 95% CI: 1.15-3.31). The extent of reverse LV remodeling at 2 years was greatest in patients in the lowest tertile (table), especially among those who underwent concomitant CABG.Conclusions:Patients with SIMR and highest tertile EROA/LVEDV ratios had greater risk of mortality after MV surgery. Greater degrees of reverse LV remodeling were observed in patients with lower ratios. Further research is needed to evaluate whether surgical interventions alter the relationship between proportionality of SIMR and outcomes.