Impact of significant preprocedural mitral regurgitation on mortality after transcatheter aortic valve implantation

Abstract

Abstract Background Mitral regurgitation (MR) is commonly encountered in patients with severe aortic stenosis scheduled for transcatheter aortic valve implantation (TAVI). The presence of significant pre-procedural MR, however, has not been accounted in pivotal trials of TAVI and data regarding its independent impact on outcome are contradictory. Methods Patients with severe and symptomatic aortic stenosis [effective orifice area (EOA) ≤1cm2] referred for TAVI at our institution were consecutively enrolled. Prospectively collected demographic, laboratory and echocardiographic data were retrospectively analysed. Patients were stratified into two groups according to MR severity: ≤ grade 1 were defined as non-significant and ≥ grade 2 as significant. Change in MR was determined by comparison between baseline and 30-day echocardiogram. Primary clinical endpoint was all-cause mortality, as defined by the criteria proposed by the Valve Academic Research Consortium2. Results A total of 331 consecutive patients were enrolled in the study: 247 (74.6%) had non-significant MR and 84 (25.4%) patients had significant MR at baseline. Patients with significant pre-procedural MR had lower baseline ejection fraction (47.7±10.4% versus 51.2±8.4%, p=0.002), higher pulmonary artery systolic pressure (52±14.3mmHg versus 42.5±11.1mmHg, p<0.0001) and higher rates of moderate or severe tricuspid regurgitation (TR) (50% versus 19.4%) compared to patients with non-significant MR. Of all patients, mitral regurgitation improved in 9.5%, remained the same in 83.9%, and worsened in 6.6% 30 days after TAVR. In a multivariable analysis, pre-procedural TR severity was predictor of improved mitral regurgitation [OR 3.003,(95% CI 1.216–7.417, p=0.017)]. The primary clinical end point occurred in 44.7% of all patients during a follow-up period of 36.6.±25.9 months. Patients with significant pre-procedural MR had significantly higher rates of all-cause mortality compared to patients with non-significant (54.7% and 41.3%, respectively; log rank p=0.015). Performing a multivariable analysis demonstrated that preprocedural MR severity could independently predict cumulative mortality [OR 0.480, (95% CI 0.247–0.932, p=0.03)]. Conclusion Significant pre-procedural MR is common in patients undergoing TAVI and is associated with increased all-cause mortality. TAVI is associated with a significant improvement in MR, especially in severe types. These data provide new insights in the crucial role of mitral regurgitation in the risk assessment of TAVI candidates. Funding Acknowledgement Type of funding sources: None.