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

https://doi.org/10.1016/j.jcin.2021.01.052Get rights and content
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Abstract

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.

Key Words

mitral annular calcification
mitral valve disease
mitral valve replacement
transcatheter mitral valve replacement

Abbreviations and Acronyms

CT
computed tomographic
IQR
interquartile range
LAMPOON
intentional laceration of the anterior mitral leaflet to prevent left ventricular outflow tract obstruction
LVOT
left ventricular outflow tract
LVOTO
left ventricular outflow tract obstruction
MAC
mitral annular calcification
MR
mitral regurgitation
MS
mitral stenosis
MV
mitral valve
THV
transcatheter heart valve
TMVR
transcatheter mitral valve replacement
ViMAC
valve–in–mitral annular calcification

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The authors attest they are in compliance with human studies committees and animal welfare regulations of the authors’ institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the Author Center.

Dr. Jermihov is currently affiliated with Morsani College of Medicine, Tampa, Florida, USA.