Impact of Residual Secondary Mitral Regurgitation on Clinical Outcomes after LVAD Implantation: An Analysis from the MOMENTUM 3 Pivotal Trial and Continuous Access Protocol Study

Objectives Secondary mitral regurgitation (MR), not amenable to percutaneous or surgical repair, is common in advanced heart failure patients considered for LVAD implantation. Single center analyses have suggested variable frequency of persistent MR after LVAD implantation and consequent pulmonary hypertension, worse right heart function and more readmissions. The contemporary impact of newer devices such as the HeartMate 3 (HM3) on amelioration of MR post-LVAD implant remains uncertain. In this analysis of the MOMENTUM 3 pivotal trial and its Continued Access Protocol (CAP) study, we propose to assess the burden of significant residual MR and to evaluate the impact on clinical outcomes. Methods Patients implanted with the HeartMate II (HMII) or HM3 pump in the MOMENTUM 3 pivotal trial were evaluated over 24 months to assess their relative impact on residual MR. An extended analysis of the first 500 implanted patients in CAP (HM3 only) will also be performed to validate observations from within the pivotal trial. Data on the presence and severity of MR using echocardiography were collected at baseline (pre-implant) and throughout the 24-month follow-up. Endpoints In the pivotal trial (n=1020), 44% of patients had significant (moderate to severe) MR at baseline and 8.8% (90/1020) had undergone a prior or concomitant mitral valve procedure. In patients with no surgical mitral valve correction, overall rates of significant residual MR (irrespective of baseline MR) at each follow-up visit are shown in Figure 1. Of those patients with significant MR at baseline, 28% had persistent significant residual MR during study follow-up. In this group, HM3 patients experienced a lower frequency of significant residual MR (24%) than HMII patients (33%, p=0.05). Survival, right heart failure, and freedom from all-cause readmissions were not significantly different between patients with and without significant residual MR. Endpoints will also be validated in the CAP cohort and in patients with concomitant mitral valve correction. (Funded by Abbott).