Does the Presence of Significant Mitral Regurgitation prior to Transcatheter Aortic Valve Implantation for Aortic Stenosis Impact Mortality? - Meta-Analysis and Systematic Review.

BACKGROUND Mitral regurgitation (MR) is commonly encountered in patients with severe aortic stenosis (AS). However, its independent impact on mortality in patients undergoing transcatheter aortic valve implantation (TAVI) has not been established. METHODS We performed a systematic search for studies reporting characteristics and outcome of patients with and without significant MR and/or adjusted mortality associated with MR post-TAVI. We conducted a meta-analysis of quantitative data. RESULTS Seventeen studies with 20,717 patients compared outcomes and group characteristics. Twenty-one studies with 32,257 patients reported adjusted odds of mortality associated with MR. Patients with MR were older, had a higher Society of Thoracic Surgeons score, lower left ventricular ejection fraction, a higher incidence of prior myocardial infarction, atrial fibrillation, and a trend towards higher NYHA class III/IV, but had similar mean gradient, gender, and chronic kidney disease. The MR patients had a higher unadjusted short-term (RR = 1.46, 95% CI 1.30-1.65) and long-term mortality (RR = 1.40, 95% CI 1.18-1.65). However, 16 of 21 studies with 27,777 patients found no association between MR and mortality after adjusting for baseline variables. In greater than half of the patients (0.56, 95% CI 0.45-0.66) MR improved by at least one grade following TAVI. CONCLUSION The patients with MR undergoing TAVI have a higher burden of risk factors which can independently impact mortality. There is a lack of robust evidence supporting an increased mortality in MR patients, after adjusting for other compounding variables. MR tends to improve in the majority of patients post-TAVI.