Clinical impact and evolution of mitral regurgitation following transcatheter aortic valve replacement: A meta-analysis

OBJECTIVES: Mitral regurgitation (MR) is a common entity in patients with aortic stenosis undergoing transcatheter aortic valve replacement (TAVR), but its influence on outcomes remains controversial. The purpose of this meta-analysis was to assess the clinical impact of and changes in significant (moderate-severe) MR in patients undergoing TAVR, overall and according to valve design (self-expandable (SEV) vs balloon-expandable (BEV)). METHODS: All national registries and randomised trials were pooled using meta-analytical guidelines to establish the impact of moderate-severe MR on mortality after TAVR. Studies reporting changes in MR after TAVR on an individual level were electronically searched and used for the analysis. RESULTS: Eight studies including 8015 patients (SEV: 3474 patients; BEV: 4492 patients) were included in the analysis. The overall 30-day and 1-year mortality was increased in patients with significant MR (OR 1.49, 95% CI 1.16 to 1.92; HR 1.32, 95% CI 1.12 to 1.55, respectively), but a significant heterogeneity across studies was observed (p<0.05). The impact of MR on mortality was not different between SEV and BEV in meta-regression analysis for 30-day (p=0.360) and 1-year (p=0.388) mortality. Changes in MR over time were evaluated in nine studies including 1278 patients. Moderate-severe MR (SEV: 326 patients; BEV: 192 patients) improved in 50.5% of the patients at a median follow-up of 180 (30-360) days after TAVR, and the degree of improvement was greater in patients who had received a BEV (66.7% vs 40.8% in the SEV group, p=0.001). CONCLUSIONS: Concomitant moderate-severe MR was associated with increased early and late mortality following TAVR. A significant improvement in MR severity was detected in half of the patients following TAVR, and the degree of improvement was greater in those patients who had received a BEV.