Prognostic impact of mitral valve geometry in patients with secondary mitral regurgitation: a secondary analysis of the MITRA-FR trial
Authors: Ng P , Riche B , Le Ruz R , Le Carpentier A , Samson G , Trochu J N , Mewton N , Guerin P , Iung B , Messika-Zeitoun D , Obadia J F , Capoulade R , Piriou N 
Published: October 2024

Abstract

Background
Mitral valve (MV) transcatheter edge-to-edge repair (TEER) has emerged as a second line therapy on top of guidelines-directed medical treatment (GDMT) in heart failure (HF) patients with severe secondary mitral regurgitation (SMR). Following the disparate results of the COAPT and MITRA-FR pivotal trials, echocardiographic markers of LV remodeling and MR severity have been proposed to select patients most likely to benefit from MV-TEER.
The characterization of MV geometry arises as a potential tool to stratify risk of outcomes in SMR patients, who underwent classical surgery or MV-TEER intervention.
However, it remains unknown whether MV geometry parameters were associated with prognosis in MITRA-FR patients and whether MV-TEER could modulate their impact on outcomes.

Purpose
To evaluate the association between MV geometry and outcomes of HF patients with SMR in the MITRA-FR trial, as well as the impact of SMR treatment modality.

Methods
Thirteen MV geometry parameters were assessed from baseline transthoracic echocardiograms in patients from the MITRA-FR trial. The prognostic impact of MV geometry parameters was studied on top of the baseline clinical variables used in the primary analysis of MITRA-FR (i.e. age, atrial fibrillation [AF], ischemic cardiomyopathy, myocardial infarction, left ventricular ejection fraction [LVEF] and effective regurgitant orifice area [EROA]). The primary endpoint was the composite of all-cause mortality or HF hospitalization (HFH) within 2 years. The effect of treatment arms (MV-TEER plus GDMT vs. GDMT alone) on this association was also evaluated.

Results
Among the 307 patients included in the pivotal trial, 272 were analyzed in the present study (i.e. 135 from the GDMT group and 137 from the GDMT + MV-TEER group). Mean age was 70±10, 74% male. 50% had ischemic cardiomyopathy and 34% AF. LVEF was 33±7% and EROA was 31±11 mm².
MV geometry parameters were presented for the whole population and according to the randomization group in the Table. Among these parameters, only MV tenting area remained independently associated with the primary endpoint (Hazard Ratio (HR) = 1.22 per 1 cm², Confidence Interval (CI) = 1.01-1.47; p=0.041) after multivariate analysis (Figure). Tenting height was independently associated with the risk of HFH (HR=1.07 per 1 mm, CI=1.00-1.14, p=0.037), but no MV geometry variable was associated with all-cause death. These findings remained consistent in both treatment arms (p&gt;0.20 for interaction).

Conclusion
In HF patients with SMR included in the MITRA-FR trial, MV tenting area and MV tenting height were independently associated with the risk of HFH or all-cause mortality and HFH respectively, without any difference according to treatment arms. These data suggest that MV tethering provides an incremental prognostic value beyond classical echocardiographic variables, including EROA, and then should be considered in the risk stratification of patients with HF and SMR.Table of MV geometry parameters featuresMultivariate analysis (Forrest-plots)