Abstract and Introduction
Abstract
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.
Introduction
Mitral regurgitation (MR) is the most frequent valvular heart disease and is frequently associated with severe aortic stenosis (AS), ranging from 3% to 74%, in elderly patients undergoing surgical aortic valve replacement (SAVR) or transcatheter aortic valve replacement (TAVR). In the presence of both, severe MR and AS, a double valve intervention is generally indicated. Moreover, a recent meta-analysis showed that even moderate MR left untreated during SAVR may be associated with poorer early and late outcomes, suggesting that double-valve surgery may be justified in such cases despite the higher perioperative mortality associated with such operations.
TAVR has been shown to be a non-inferior or even a superior alternative to SAVR in patients with severe AS and a high-risk profile. However, significant (moderate or severe) MR is present in ~15% of patients undergoing TAVR and in this setting MR is usually left untreated. It is therefore of utmost importance to determine the clinical impact of and changes in MR in patients undergoing TAVR; this may have important implications in the clinical decision-making process for patients with AS eligible for either TAVR or SAVR. The impact of concomitant MR on clinical outcomes has been arbitrarily reported in single-centre and multicentre TAVR series, but no systematic analysis of large series has been performed to date. Moreover, two recent large studies, with different transcatheter valves, reported contradictory results. Thus, it has been hypothesised that self-expandable valves may impair mitral valve function and the impact of MR on mortality may vary according to valve type. Also, highly variable results have been reported in the literature with respect to MR changes following TAVR, with an improvement rate ranging from 12% up to 80%. We therefore undertook a comprehensive meta-analysis with the objective of (i) assessing the impact of moderate–severe MR on early and late mortality in patients included in TAVR national registries and randomised trials, and (ii) determining the changes in MR severity following TAVR overall and according to valve type (balloon-expandable valve (BEV) vs self-expandable valve (SEV)).