Prospective Study of TMVR Using Balloon-Expandable Aortic Transcatheter Valves in MAC: MITRAL Trial 1-Year Outcomes.

Objectives: The aim of this study was to evaluate 1-year outcomes of valve-in-mitral annular calcification (ViMAC) in the MITRAL (Mitral Implantation of Transcatheter Valves) trial.
Background: The MITRAL trial is the first prospective study evaluating the feasibility of ViMAC using balloon-expandable aortic transcatheter heart valves.
Methods: A multicenter prospective study was conducted, enrolling high-risk surgical patients with severe mitral annular calcification and symptomatic severe mitral valve dysfunction at 13 U.S. sites.
Results: Between February 2015 and December 2017, 31 patients were enrolled (median age 74.5 years [interquartile range (IQR): 71.3 to 81.0 years], 71% women, median Society of Thoracic Surgeons score 6.3% [IQR: 5.0% to 8.8%], 87.1% in New York Heart Association functional class III or IV). Access was transatrial (48.4%), transseptal (48.4%), or transapical (3.2%). Technical success was 74.2%. Left ventricular outflow tract obstruction (LVOTO) with hemodynamic compromise occurred in 3 patients (transatrial, n = 1; transseptal, n = 1; transapical, n = 1). After LVOTO occurred in the first 2 patients, pre-emptive alcohol septal ablation was implemented to decrease risk in high-risk patients. No intraprocedural deaths or conversions to open heart surgery occurred during the index procedures. All-cause mortality at 30 days was 16.7% (transatrial, 21.4%; transseptal, 6.7%; transapical, 100% [n = 1]; p = 0.33) and at 1 year was 34.5% (transatrial, 38.5%; transseptal, 26.7%; p = 0.69). At 1-year follow-up, 83.3% of patients were in New York Heart Association functional class I or II, the median mean mitral valve gradient was 6.1 mm Hg (IQR: 5.6 to 7.1 mm Hg), and all patients had ≤1+ mitral regurgitation.
Conclusions: At 1 year, ViMAC was associated with symptom improvement and stable transcatheter heart valve performance. Pre-emptive alcohol septal ablation may prevent transcatheter mitral valve replacement-induced LVOTO in patients at risk. Thirty-day mortality of patients treated via transseptal access was lower than predicted by the Society of Thoracic Surgeons score. Further studies are needed to evaluate safety and efficacy of ViMAC.
Competing Interests: Funding Support and Author Disclosures This study was supported by an unrestricted research grant from Edwards Lifesciences. Dr. Guerrero has received research grant support from Abbott Vascular and Edwards Lifesciences. Dr. Wang has served as a consultant for Edwards Lifesciences, Boston Scientific, Materialise, and HighLife Medical; and has received grant support from Boston Scientific. Dr. Salinger has served as a proctor for Boston Scientific and Edwards Lifesciences. Dr. Kodali has served as a consultant for Admedus, Meril Lifesciences, Abbott Vascular, JenaValve, and Claret Medical; and has ownership interest in Dura Biotech, Thubrikar Aortic Valve, Microinterventional Devices, and Supira Medical. Dr. George has served as a consultant for Boston Scientific, Medtronic, Edwards Lifesciences, and W.L. Gore & Associates. Dr. Bapat has served as a consultant for Edwards Lifesciences, Medtronic, and Sorin. Dr. Meduri has served as a consultant for Medtronic and Boston Scientific; and has served on the advisory board for Boston Scientific. Dr. Tang is a physician proctor for Medtronic; and is a consultant for Medtronic, Abbott Structural Heart, and W.L. Gore & Associates. Dr. Reisman has served as a consultant for Edwards Lifesciences. Dr. Feldman is an employee of Edwards Lifesciences. Dr. Hahn has received speaker fees from Baylis Medical, Edwards Lifesciences, and Medtronic; is a consultant for Abbott Structural Heart, Edwards Lifesciences, W.L. Gore & Associates, Medtronic, Navigate, and Philips Healthcare; has received nonfinancial support from 3mensio Medical Imaging; holds equity in Navigate; and is the chief scientific officer for the Echocardiography Core Laboratory at the Cardiovascular Research Foundation for multiple industry-sponsored trials, for which she receives no direct industry compensation. Dr. O’Neill has served as a consultant for Abiomed, Boston Scientific, and Edwards Lifesciences. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
(Copyright © 2021 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)