Impact of Baseline Anteroposterior Mitral Annular Dimensions on Clinical Outcomes after MitraClip for Secondary Mitral Regurgitation

Background

In the randomized Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation (COAPT; NCT01626079) trial, mitral transcatheter edge-to-edge repair (M-TEER) improved clinical outcomes in patients with severe secondary mitral regurgitation (MR). A prior post hoc analysis from the COAPT trial showed that increasing anteroposterior mitral annular diameter (APMAD) was the sole independent echocardiographic predictor of the composite endpoint of death or heart failure hospitalizations (HFH) at 2 years. Given the relationship between the mitral annulus and leaflets, we examined the association of baseline APMAD with long-term clinical outcomes.

Methods

COAPT patients (n = 575) were stratified into tertiles by baseline APMAD as follows: small APMAD, medium APMAD, and large APMAD. APMAD was measured in the anteroposterior direction from the parasternal long-axis view at end-diastole and in the intercommissural direction from the apical two-chamber view.

Results

Patients with larger baseline APMAD were more often male and had fewer comorbidities, larger ventricles, and larger mitral orifice areas. At 2 years, there were no significant differences in MR severity and the composite endpoint of death or HFH in patients treated with M-TEER by baseline APMAD. In patients treated with guideline-directed medical therapy (GDMT) alone, there were no significant differences in MR severity, but the composite endpoint of death or HFH was higher in patients with the largest baseline APMADs. The treatment effect of M-TEER was consistent among APMAD tertiles (p_interaction = 0.87).

Conclusions

APMAD was a predictor of adverse outcomes in patients treated with GDMT alone. M-TEER reduced MR severity and the risk of death or HFH regardless of baseline APMAD compared with GDMT alone.