The REDUCE FMR Trial: A Randomized Sham-Controlled Study of Percutaneous Mitral Annuloplasty in Functional Mitral Regurgitation

Objectives: This study sought to evaluate the effects of the Carillon device on mitral regurgitation severity and left ventricular remodeling.

Background: Functional mitral regurgitation (FMR) complicates heart failure with reduced ejection fraction and is associated with a poor prognosis.

Methods: In this blinded, randomized, proof-of-concept, sham-controlled trial, 120 patients receiving optimal heart failure medical therapy were assigned to a coronary sinus-based mitral annular reduction approach for FMR or sham. The pre-specified primary endpoint was change in mitral regurgitant volume at 12 months, measured by quantitative echocardiography according to an intention-to-treat analysis.

Results: Patients (69.8 ± 9.5 years of age) were randomized to either the treatment (n = 87) or the sham-controlled (n = 33) arm. There were no significant differences in baseline characteristics between the groups. In the treatment group, 73 of 87 (84%) had the device implanted. The primary endpoint was met, with a statistically significant reduction in mitral regurgitant volume in the treatment group compared to the control group (decrease of 7.1 ml/beat [95% confidence interval [CI]: -11.7 to -2.5] vs. an increase of 3.3 ml/beat [95% CI: -6.0 to 12.6], respectively; p = 0.049). Additionally, there was a significant reduction in left ventricular volumes in patients receiving the device versus those in the control group (left ventricular end-diastolic volume decrease of 10.4 ml [95% CI: -18.5 to -2.4] vs. an increase of 6.5 ml [95% CI: -5.1 to 18.2]; p = 0.03 and left ventricular end-systolic volume decrease of 6.2 ml [95% CI: -12.8 to 0.4] vs. an increase of 6.1 ml [95% CI: -1.42 to 13.6]; p = 0.04).

Conclusions: The Carillon device significantly reduced mitral regurgitant volume and left ventricular volumes in symptomatic patients with functional mitral regurgitation receiving optimal medical therapy. (Carillon Mitral Contour System for Reducing Functional Mitral Regurgitation [REDUCE FMR]; NCT02325830).