Background

The evidence regarding favorable treatment of patients with functional mitral regurgitation (FMR) using transcatheter edge-to-edge repair (TEER) is constantly growing. However, there is only few data directly comparing TEER and conventional surgical mitral valve repair (SMVR).

Objectives
To compare baseline characteristics as well as short-term and 1-year outcomes in FMR patients undergoing mitral valve repair with the MitraClip (MC) system or SMVR using a meta-analytic approach.

Methods
Systematic database search identified 426 studies reporting on MC or SMVR treatment for FMR between January 2010 and August 2020. In 44 eligible studies clinical outcomes were assessed by in-hospital, 30-day and 1-year mortality. Combination of clinical outcomes and risk factors from single-arm and randomized studies followed a meta-analytic approach based on comparison of measures by means of their corresponding 95% confidence interval (CI). Study heterogeneity was assessed using I². Statistical significance was assumed if CI did not overlap.

Results

22 MC and 22 SMVR studies comprising 4356 and 2054 patients were included in our analysis. Patients in the MC cohort presented with higher age (71.9 ±1.7 vs. 64.1 ±5.72 years; p<0.001) and a greater burden of comorbidities like hypertension (74.5% ±9.8 vs. 55.1% ±8.1; p<0.001), atrial fibrillation (51.9% ±13.5 vs. 25.9 ±15.3; p<0.001), history of CABG (37.9% ±10.7 vs. 11.2% ±9.3; p<0.001) and chronic renal disease (34.4% ±14.5 vs. 20.3% ±10.2; p=0.028). Consequently, MC patients showed a higher logistic Euro Score (22.3 ±4.4 vs. 11.4 ±2.5; p<0.001). In-hospital mortality was significantly lower in the MC cohort (3% [95%-CI 0.02 – 0.04; I2=0%] vs. 7% [95%-CI 0.05– 0.08; I2=38%]). 30-day mortality was comparable between both groups (MC: 4% [95%-CI 0.03 - 0.05; I2=45%] vs. SMVR: 4% [0.03 - 0.07; I2=55%]) and 1-year mortality did not differ significantly (18% [95%-CI 0.15 - 0.21; I2=67%] vs. 11% [0.06 - 0.17; I2=72%]). Meta-regression analysis revealed NYHA class IV as a significant moderator of 30-day mortality for the MC procedure (estimate 3.14; 95%-CI 1.31 – 4.98; p<0.001).

Conclusion

Despite considerably higher age, comorbidity burden and logistic Euro Score, in-hospital mortality was substantially lower in patients treated with TEER. 30-day and 1-year mortality did not differ significantly between the MC and SMVR cohorts.