Natural history and predictors of outcome in patients with concomitant functional mitral regurgitation at the time of aortic valve replacement

BACKGROUND - Concomitant functional mitral regurgitation (FMR) in patients undergoing aortic valve replacement (AVR) is frequently not corrected because it may improve after AVR; however, data supporting this assumption are sparse. We ascertained the impact of clinical and echocardiographic parameters on the outcome of patients with or without concomitant FMR at the time of AVR. METHODS AND RESULTS - Clinical and echocardiographic follow-up was performed on 848 patients who underwent AVR after 1990. Risk factors for mortality and a composite outcome of heart failure (CHF) symptoms, CHF death, or subsequent mitral repair or replacement, were examined with bootstrapped Cox proportional hazard models. Follow-up was 4591 patient-years (mean 5.4±3.4 years; maximum 14.2 years). FMR ≥2+ had no independent adverse effect on survival in patients with aortic stenosis (AS) or insufficiency (AI). However, AS patients with FMR ≥2+ and 1 additional risk factor (left atrial diameter >5 cm, preoperative peak aortic valve gradient <60 mm Hg, or atrial fibrillation) were at increased risk for the composite outcome (hazard ratio [HR]: 2.7; P=0.004). AI patients with FMR ≥2+ and a left ventricular end-systolic diameter <45 mm were also at risk (HR: 4.0; P=0.02). Clinical risk factors in the AS and AI subgroups were associated with an increased likelihood of mitral regurgitation ≥2+ at 18 months postoperatively. CONCLUSIONS - AS patients with FMR ≥2+ and a left atrial diameter >5 cm, preoperative peak aortic valve gradient <60 mm Hg, or atrial fibrillation have a significantly higher risk of CHF and persistent mitral regurgitation after AVR than other AS patients. AI patients with FMR ≥2+ and a left ventricular end-systolic diameter <45 mm preoperatively are also at increased risk. Others fare well after AVR.