Acute changes of right ventricular longitudinal strain after transcatheter edge-to-edge repair in patients with functional mitral regurgitation
Authors: Ruotolo I , Marcelli C , Barile L , Catalano C , Saturi G , Ditaranto R , Parisi V , Baldassarre R , Di Nicola F , Nardi E , Palmerini T , Saia F , Galie' N , Berardini A , Biagini E 
Published: November 2023

Abstract

Background
Transcatheter edge-to-edge repair (TEER) is a valid therapeutic option in symptomatic patients with severe secondary mitral valve regurgitation (SMR) at high surgical risk. While right ventricular (RV) dysfunction is a predictor of poor outcomes in this context, TEER may lead to an improvement of RV function which portends a better outcome.

Purpose
The aim of this study was to investigate acute change in RV function and its prognostic implication after successful TEER in patients with severe SMR.

Methods
Patients with severe SMR who underwent TEER from 2013 to 2021 at our center were retrospectively screened. Only patients with successful procedure (MR ≤ grade 2) and adequate echocardiographic images for longitudinal strain assessment were enrolled. RV function was estimated at baseline and pre-discharge by echocardiographic evaluation; RV global longitudinal strain (RVGLS) and RV free wall longitudinal strain (RVFWLS) were assessed before and after TEER. Longitudinal strain improvement was defined as an increase of post procedural strain greater than median value variation. Population was then divided in two groups based on RVGLS significant improvement. The primary outcome was a composite of all-cause death, heart transplantation (HT) and left ventricular assist device (LVAD) implantation during follow-up, assessed with Kaplan-Maier curves and compared by log-rank test.

Results
A total of 61 patients were included. Mean age was 70±10 years, 89% patients were symptomatic with NYHA class 3-4, mean furosemide daily dose was 200±146 mg. Pre-TEER median left ventricle ejection fraction (LVEF) was 29% [IQR, 26; 35%], RV fractional area change (FAC) was 32% [IQR 26; 37%] and tricuspid anulus plan systolic excursion (TAPSE) was 17 mm [IQR 14; 20 mm]. Median RVGLS and RVFWLS at baseline were respectively -11% [IQR -13; -9%] and -14% [IQR -17; -11%]. After TEER a significant variation of RVGLS and RVFWLS was observed (RVGLS: -13% [IQR -15; -10%] p 0.012; RVFWLS: -16% [-19; - 13%] p 0.001). Moreover, a significant reduction in estimated systolic pulmonary artery pressure (sPAP) between baseline (45 mmHg [IQR 35; 55mmHg]) and post TEER (40 mmHg [IQR 30;45 mmHg] p &lt;0.001) was observed. Median improvement of RVGLS was 1.3%. After mean follow up time of 55±7 months event rate for the combined primary endpoint was numerically lower in the improved RVGLS group, although the difference was not statistically significant (p 0.243). Interestingly, rate of HT was significantly lower in RVGLS-improved group (p 0.032).

Conclusions
This study showed significant pre-discharge improvement of RV longitudinal strain in patient with severe SMR after successful TEER. At follow-up this improvement did not affect the outcome in terms of freedom from composite endpoint of all-cause death, HT or LVAD implantation but events were numerically lower in patients with strain improvement. Further data on larger population are needed to confirm our observations.Table 1,2Figure 1,2