Prediction of Cardiovascular Events and Structural and Functional Remodeling of the Heart in Patients With Severe Mitral Regurgitation of Various Genesis Underwent Transcatheter Mitral Valve Repair "Edge-To-Edge".

Aim: To search for predictors of adverse cardiovascular events after edge-to-edge transcatheter mitral valve repair (TMVR) in patients with severe mitral regurgitation (MR) of various origins with an assessment of structural and functional remodeling of the heart and left ventricular (LV) contractile function.

Material and methods: The study included 73 patients (median age 71 [63; 80] years, 60.3% men) at a high surgical risk with severe MR of primary and secondary genesis, who underwent TMVR. The second-generation (58.9%) and fourth-generation (41.1%) clips were implanted. In addition to standard echocardiographic (EchoCG) indices, the parameters of left heart chamber longitudinal strain and LV myocardial function were assessed at baseline, on days 4-5, and at 6 and 12 months after the intervention. Also, the N-terminal fragment of the pro-brain natriuretic peptide (NT-proBNP) was assessed at baseline and on days 4-5 after TMVR.

Results: A significant decrease in MR was achieved during 12 months of follow-up. In the group with primary mitral regurgitation (PMR), MR decreased from 4.0 [3.4; 4.0] to 2.0 [1.5; 2.5] at one year of follow-up (p<0.001). In the group with secondary mitral regurgitation (SMR), MR decreased from 3.5 [3.0; 3.9] to 2.0 [2.0; 2.5] at 12 months of follow-up (p<0.001). This effect was associated with volumetric unloading of the left heart chambers evident as a significant decrease in the volumetric indices of the left chambers and an increase in the cardiac index. In the early postoperative period, the LV function was impaired as shown by decreases in the ejection fraction (EF), global longitudinal strain (GLS), LV myocardial function parameters, and an associated increase in NT-proBNP. By 12 months of follow-up, statistically significant improvements in global constructive work (GCW) and global work index (GWI) relative to baseline values were noted in both groups without significant changes in EF and LV GLS. A strong correlation was found between LV EF and GCW (r=0.812, p<0.001) and GWI (r=0.749, p<0.001). The overall survival was 89%, not differing between groups (p=0.72); the absence of hospitalization for decompensated heart failure (HF) was 79.5%, also without significant differences between the groups (p=0.78). According to multivariate regression analysis, the baseline GCW value was the strongest predictor of rehospitalization for decompensated HF (relative risk (RR) 0.997; 95% confidence interval (CI) 0.995-1.000; p=0.021) and the composite endpoint (CEP) (hospitalization for decompensated HF + all-cause mortality) (RR 0.998; 95% CI 0.996-1.000; p=0.033) in the cohort with PMR. In the group with SMR, the initial degree of MR was related with rehospitalization and the CEP (OR 12.252; 95% CI 2.125-70.651; p=0.005 and OR 16.098; 95% CI 2.944-88.044; p=0.001, respectively). The most significant predictor of overall mortality in the study population was the preoperative value of LV stroke volume (OR 0.824; 95% CI 0.750-0.906; p<0.001).

Conclusion: Edge-to-edge TMVR exerts a positive effect on the prognosis and structural and functional remodeling of the heart in patients with PMR and SMR. Myocardial function indices may be useful in assessing the LV contractile function in patients with severe MR of various origins. Identification of predictors for adverse cardiovascular events, including with new EchoCG technologies, may contribute to better patient stratification.