Echocardiographic Outcomes After Transcatheter Leaflet Approximation in Patients With Secondary Mitral Regurgitation: The COAPT Trial

Background: In the COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation) trial among patients with heart failure (HF) and moderate-to-severe (3+) or severe (4+) secondary mitral regurgitation, patients treated with transcatheter mitral valve repair (TMVr) through leaflet approximation had reduced rates of HF hospitalization and mortality compared with guideline-directed medical therapy (GDMT) alone.

Objectives: The purpose of this study was to describe the echocardiographic patient qualification process for the COAPT trial, baseline echocardiographic characteristics, changes over time, and the interaction between treatment group and echocardiographic parameters on clinical outcomes.

Methods: A novel echocardiographic algorithm was implemented for grading mitral regurgitation severity during the screening process. Standardized echocardiograms were obtained at baseline and during regular follow-up intervals through 2 years, and were analyzed by a core laboratory.

Results: A total of 614 patients were randomized to TMVr plus maximally tolerated GDMT or GDMT alone. Mean baseline left ventricular (LV) ejection fraction was 31.3 ± 9.3%, LV end-diastolic volume was 192.7 ± 71 ml, and effective regurgitant orifice area was 0.41 ± 0.15 cm². The beneficial effect of TMVr compared with GDMT alone was consistent in all echocardiographic subgroups, independent of the severity of LV dysfunction, LV dilatation, pulmonary hypertension, severity of tricuspid regurgitation, or individual mitral regurgitation characteristics. The LV ejection fraction decreased and the LV volumes progressively increased in both groups during follow-up, although less after TMVr (p < 0.05).

Conclusions: HF patients in the COAPT trial with 3+ or 4+ secondary mitral regurgitation, selected using strict echocardiographic criteria, benefitted from TMVr with reduced 2-year rates of death and HF hospitalization. Strict application of these echocardiographic criteria should enable the COAPT results to be translated to clinical practice. (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation [The COAPT Trial] [COAPT]; NCT01626079).