The impact of unstable results following transcatheter mitral edge-to-edge repair on long-term outcomes
Authors: Pauschinger C , Koell B , Weimann J , Schirmer J , Reichenspurner H , Ludwig S , Conradi L , Schaefer A , Blankenberg S , Schofer N , Kalbacher D 
Published: November 2023

Abstract

Background
Mitral regurgitation (MR) is associated with reduced quality of life and increased mortality. Mitral edge-to-edge repair (M-TEER) is an alternative for patients (pts) not suitable for open-heart surgery.
The severity of residual MR (rMR) following M-TEER is associated with lower long-term survival rates. The prognostic implications of recurrent MR, e.g. an unstable result during follow-up, have not been explored.

Purpose
This single-center, retrospective study analyzed the incidence of unstable results (defined as worsening rMR during short-term follow-up) and its impact on mid- and long-term outcomes in pts treated with M-TEER.

Methods
We included a total of 1,030 pts treated by M-TEER between 09/2008 and 11/2019 for either relevant degenerative MR (DMR) or severe functional MR (FMR) at our single center. 467 pts were excluded due to insufficient long-term follow-up data, 134 pts were excluded due to rMR ≥3+ or missing values for rMR at discharge, and one patient with lack of classification into FMR or DMR. Therefore, a total of 428 pts with a median follow-up of 4.61 (95%-confidence interval [95%-CI]: 4.41; 4.96) years were analyzed. Unstable results were defined as an increase in the amount of rMR (≥1+) at 6- or 12-month follow-up compared to discharge. Follow-up was shortened to 5-years for all pts. The primary endpoint was all-cause mortality.

Results
428 pts (mean age 74.6 ± 9.1 years, 36.9% female, median STS score 3.6%, DMR in 28.0%, FMR in 72.0%) were stratified according to the presence or absence of an unstable result (FMR: n=101/308 [32.8%] vs. DMR: n=35/120 [29.2%]). The mean left ventricular ejection fraction (LVEF) was 41.6% (± 15), median NT-proBNP was 3,333 pg/ml [interquatile range 1,676; 6,673]. Glomerular filtration rate (GFR) &lt;30mL/min was found in 11.2%. There were no significant differences in baseline characteristics, except for the mean systolic pulmonary artery pressure (SPAP) in the DMR subset of pts (median SPAP: 51.0 mmHg vs. 39.0 mmHg for unstable vs. stable, p=0.009).
171 pts (39.9%) died during follow-up. Kaplan-Meier 12-months analysis for survival demonstrated significant differences for the primary endpoint with superior outcomes for pts presenting with stable results during follow-up (p log rank=0.02, Figure 1). Univariable Cox regression analysis indicated a significant association of an unstable results with increased mortality rates (hazard ratio [HR]=1.44; 95%-CI: 1.05-1.96; p=0.022). The association still proved to be significant following multivariable adjustment for age, LVEF≤30%, anaemia, FMR, GFR&lt;30ml/min, and atrial fibrillation (HR=1.43; 95%-CI:1.03-1.97; p=0.031).

Conclusion
An unstable result characterized by worsening rMR during the first 12 months after M-TEER appears to be an independent predictor of increased mortality risk. Therefore, predictors of unstable results as well as its impact on functional outcomes should be subject of further investigation.Kaplan-Meier 12-month landmark Analysis