Outcomes of transcatheter mitral valve repair for secondary mitral regurgitation by severity of left ventricular dysfunction

Background: In the COAPT trial, transcatheter mitral valve repair with the MitraClip plus maximally tolerated guideline-directed medical therapy (GDMT) improved clinical outcomes compared with GDMT alone in symptomatic patients with heart failure (HF) and 3+ or 4+ secondary mitral regurgitation (SMR) due to left ventricular (LV) dysfunction. Aims: In this COAPT substudy, we sought to evaluate two-year outcomes in HF patients with reduced LV ejection fraction (HFrEF; LVEF ≤40%) versus preserved LVEF (HFpEF; LVEF >40%) and in those with severe (LVEF ≤30%) versus moderate (LVEF >30%) LV dysfunction. Methods: The principal effectiveness outcome was the two-year rate of death from any cause or HF hospitalisations (HFH). Subgroup analysis with interaction testing was performed according to baseline LVEF; 472 patients (82.1%) had HFrEF (mean LVEF 28.0%±6.2%; range 12% to 40%) and 103 (17.9%) had HFpEF (mean LVEF 46.6%±4.9%; range 41% to 65%), while 292 (50.7%) had severely depressed LVEF (LVEF ≤30%; mean LVEF 23.9%±3.8%) and 283 (49.3%) had moderately depressed LVEF (LVEF >30%; mean LVEF 39.0%±6.8%). Results: The two-year rate of death or HFH was 56.7% in patients with HFrEF and 53.4% with HFpEF (HR 1.16, 95% CI: 0.86-1.57, p=0.32). MitraClip reduced the two-year rate of death or HFH in patients with HFrEF (HR 0.50, 95% CI: 0.39-0.65) and HFpEF (HR 0.60, 95% CI: 0.35-1.05), p_int=0.55. MitraClip was consistently effective in reducing the individual endpoints of mortality and HFH, improving MR severity, quality of life, and six-minute walk distance in patients with HFrEF, HFpEF, LVEF ≤30%, and LVEF >30%. Conclusions: In the COAPT trial, among patients with HF and 3+ or 4+ SMR who remained symptomatic despite maximally tolerated GDMT, the MitraClip was consistently effective in improving survival and health status in patients with severe and moderate LV dysfunction and those with preserved LVEF.