Influence of Cardiac Remodeling on Clinical Outcomes in Patients With Aortic Regurgitation

Background: Quantitative cardiac magnetic resonance (CMR) outcome studies in aortic regurgitation (AR) are few. It is unclear if volume measurements are beneficial over diameters. Objectives: This study sought to evaluate the association of CMR quantitative thresholds and outcomes in AR patients. Methods: In a multicenter study, asymptomatic patients with moderate or severe AR on CMR with preserved left ventricular ejection fraction (LVEF) were evaluated. Primary outcome was development of symptoms or decrease in LVEF to <50%, development of guideline indications for surgery based on LV dimensions, or death under medical management. Secondary outcome was the same as the primary outcome, excluding surgery for remodeling indications. We excluded patients who underwent surgery within 30 days of CMR. Receiver-operating characteristic analyses for the association with outcomes were performed. Results: We studied 458 patients (median age: 60 years; IQR: 46-70 years). During a median follow-up of 2.4 years (IQR: 0.9-5.3 years), 133 events occurred. Optimal thresholds were regurgitant volume of 47 mL and regurgitant fraction of 43%, indexed LV end-systolic (iLVES) volume of 43 mL/m², indexed LV end-diastolic volume of 109 mL/m², and iLVES diameter of 2 cm/m². In multivariable regression analysis, iLVES volume of ≥43 mL/m² (HR: 2.53; 95% CI: 1.75-3.66; P < 0.001) and indexed LV end-diastolic volume of ≥109 mL/m² were independently associated with the outcomes and provided additional discrimination improvement over iLVES diameter, whereas iLVES diameter was independently associated with the primary outcome but not the secondary outcome. Conclusions: In asymptomatic AR patients with preserved LVEF, CMR findings can be used to guide management. CMR-based LVES volume assessment performed favorably compared to LV diameters.