Strain Analysis of Ventricular Function: A Prognostic Tool for Mitral Valve Repair Success in FMR Patients with Preserved or Mildy Reduced LV Function

Background:
Patients with heart failure and preserved or mildly reduced ejection fraction represent at least half of the heart failure population. Yet, there are fewer treatment options with evidence based prognostic benefit concerning medical as well as interventional strategies. While mitral valve transcatheter edge-to-edge repair (M-TEER) has been shown to be an effective treatment in heart failure with reduced ejection fraction and relevant functional mitral regurgitation (FMR), data apart from that remains scarce. Therefore, we aimed to evaluate outcome and hemodynamic effects by echocardiographic strain measurements in this special collective.

Methods:
We retrospectively enrolled patients with a relevant symptomatic FMR (≥ grade II) and non-reduced left ventricular ejection fraction (HFnonrEF, LVEF > 40 %) that have been treated at the University Hospital Bonn between 01/2020 and 12/2023. Echocardiographic studies at baseline and follow-up (3 to 6 months and 12 months) were meticulously post-processed through advanced speckle-tracking strain analysis, ensuring precise assessment of myocardial deformation and function over time. The study-collective was subdivided in groups representing treatment by guideline-directed medical therapy (GDMT) and M-TEER and GDMT only. A control group without relevant MR but equally HFnonrEF was analysed for comparison reasons.  

Results:
According to the above-mentioned criteria, we analysed 263 patients (48,7 % female, mean age: 77 years), of whom 70 patients (26 %) were treated by M-TEER and 44 patients by GDMT only. Conventional echocardiographic measurements revealed an overall procedural success with a significant improvement to a residual MR grade ≤ II in 98,5 % of patients at second follow-up examination (p < 0,001 respectively). Functional capacity also showed significant enhancement from a NYHA-class ≥ II in 91,5 % at baseline to a grade ≤ II in 65,9 % at second follow-up (p = 0,028). Performing right ventricular global longitudinal strain (RVGLS) analysis, we found significant worse right ventricular function in M-TEER-collective at baseline (-21 % vs. -18 %, p < 0,001) that was not detectable after the procedure (-21,3 % vs. -21,6 %; p = 0,61). Patients reaching the endpoint mortality also displayed significantly reduced RVGLS values at all examinations (e.g. -20,5 % vs. -17,5 %; p < 0,001). A logistic regression model (p = 0.03) incorporating age, sex, and baseline MR as cofactors demonstrated a significant effect of RVGLS on mortality (p = 0.024; B = 0.39; OR = 1.49). No significant change in left ventricular global longitudinal strain (LVGLS) was observed following the M-TEER procedure. However, patients who reached the mortality endpoint tended to have lower LVGLS values (-18% vs. -16.3%; p = 0.02).

Conclusion:
The findings establish M-TEER as a highly effective therapeutic option for patients with FMR and HFnonrEF. Strain analysis provided critical insights into peri-interventional hemodynamic changes, highlighting significant improvements in initially impaired right ventricular function. Additionally, baseline RVGLS analysis emerged as a valuable prognostic marker for outcomes in patients with FMR and HFnonrEF, supporting its role in guiding patient management.