Degenerative mitral regurgitation predicts worse outcomes in patients undergoing transcatheter aortic valve replacement

Combined Significant Aortic Stenosis and Mitral Regurgitation: Challenges in Timing and Type of Intervention

In this narrative review, we aim to summarize the literature surrounding the assessment and management of the common, yet understudied combination of aortic stenosis (AS) and mitral regurgitation (MR), the components of which are complexly inter-related and interdependent from diagnostic, prognostic, and therapeutic perspectives. The hemodynamic interdependency of AS and MR confounds the assessment of the severity of each valve disease, thus underscoring the importance of a multimodal approach integrating valvular and extravalvular indicators of severity. A large body of literature suggests that baseline MR is associated with reduced survival post aortic valve (AV) intervention and that regression of MR post-AV intervention confers a mortality benefit. Functional MR is more likely to regress after AV intervention than primary MR. The respective natural courses of the 2 valve diseases are not synchronized; therefore, significant AS and MR at or above the respective threshold for intervention might not coincide. Surgery is primarily a 1-stop-shop procedure because of a considerable perioperative risk of repeat interventions, whereas transcatheter treatment modalities allow for a more tailored timing of intervention with reassessment of concomitant MR after AV replacement and a potential staged intervention in the absence of MR regression. In summary, AS and MR, when combined, are interlaced into a complex hemodynamic, diagnostic, and prognostic synergy, with important therapeutic implications. Contemporary approaches should consider stepwise intervention by exploiting the advantage of transcatheter options. However, evidence is needed to demonstrate the efficacy of different timing and therapeutic options.

Managing the patient undergoing transcatheter aortic valve replacement with ongoing mitral regurgitation

INTRODUCTION

Significant mitral regurgitation (MR) frequently coexists in patients with severe symptomatic aortic stenosis undergoing transcatheter aortic valve replacement (TAVR). These patients have worse clinical outcomes than those with non-significant MR, especially if MR persists after treatment of the aortic stenosis. The optimal treatment approach for this challenging high-risk population is not well defined.

AREAS COVERED

This review aims to present the current literature on concomitant significant MR in the TAVR population, and to provide a comprehensive algorithmic approach for clinical decision-making in this challenging cohort of patients.

EXPERT OPINION

Concomitant mitral and aortic valve disease is a complex clinical entity. An exhaustive and comprehensive assessment of patient's clinical characteristics and mitral valve anatomy and function is required in order to assess the surgical risk, predict the MR response after AVR and evaluate the feasibility of percutaneous MV treatment if necessary. Further developments in transcatheter techniques will expand the indications for double valve treatment in operable and inoperable patients with concomitant significant MR and aortic stenosis.

Combined Transcatheter Replacement of Aortic Root and Mitral Valve in an Acute Preclinical Study

The study aimed to evaluate the early feasibility of endovascular replacement of ascending aorta, aortic root (including aortic valve, AV), and mitral valve (MV) in one procedure with two self-expandable prostheses. Aortic valved-fenestrated-bifurcated (AVFB) and MV endografts of 10 healthy pigs (60-65kg) were customized and delivered through transapical and transseptal approach, respectively. Both endografts were successfully deployed in nine pigs (90%). Eight survived over 24 h, and the acute success rate was 80%. There was no significant increase in the mean trans-aortic, trans-mitral, and trans-LVOT pressure gradients after the operation. No coronary artery or LVOT obstruction and other electrocardiographic abnormality occurred. The transvalvular and paravalvular leak rates were low for both valves. Endovascular replacement of ascending aorta, AV, and MV in one procedure might be feasible. Combined transcatheter replacement of aortic root and mitral valve in one procedure.

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.