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.