Dapagliflozin effect on functional mitral regurgitation and myocardial remodelling: The DEFORM trial

Aims Functional mitral regurgitation (FMR) is associated with adverse outcomes in patients with heart failure, and current guideline‐directed medical therapy (GDMT) offers limited efficacy in managing FMR. This study aims to evaluate the therapeutic impact of the sodium‐glucose cotransporter 2 inhibitor (SGLT2i) dapagliflozin in patients with moderate or severe FMR. Methods and results In this randomized controlled trial, 104 patients with moderate or severe FMR were assigned in a 1:1 ratio to receive either dapagliflozin 10 mg once daily or no additional treatment alongside current GDMT for FMR, with a follow‐up period of 3 months. The primary endpoint was the change in effective regurgitant orifice area (EROA) of mitral regurgitation (MR). Secondary endpoints included changes in regurgitant volume (RV), left ventricular end‐diastolic volume (LVEDV), left ventricular end‐systolic volume (LVESV), left ventricular mass (LVM), left ventricular mass index (LVMI), left ventricular ejection fraction (LVEF), E/e′ ratio, and left atrial volume index (LAVI). The incidence of hospitalization for heart failure or cardiovascular death was also compared between the groups. As a result, dapagliflozin significantly reduced the EROA of FMR (−0.074 ± 0.099 vs. −0.030 ± 0.058 cm 2 for dapagliflozin vs. control, P = 0.008). It also significantly decreased RV (−9.08 ± 15.27 vs. −2.98 ± 9.28 mL, P = 0.017), E/e′ ratio (−5.88 ± 7.41 vs. −1.98 ± 7.63, P = 0.011), and LAVI (−2.50 ± 4.75 vs. −0.43 ± 3.14 mL/m 2 , P = 0.011) while improving LVEF (6.57 ± 10.10 vs. 1.92 ± 9.57%, P = 0.017). No significant differences were observed in changes in LVEDV, LVESV, LVM, and LVMI between groups ( P > 0.05). Hospitalization for heart failure occurred in 9.6% of the dapagliflozin group and 15.3% of the control group (hazard ratio, 0.60; 95% CI, 0.20–1.83; P = 0.368). Cardiovascular death occurred in 1.9% of the dapagliflozin group compared to 3.8% of the control group (hazard ratio, 0.49; 95% CI, 0.04–5.41; P = 0.561) during the 3‐month follow‐up. Conclusions Dapagliflozin demonstrates the potential to further reduce the degree of MR and enhance myocardial remodelling in patients with FMR when used in addition to current GDMT. These findings suggest the importance of SGLT2i in heart failure patients with FMR as an additive positive effect on echocardiographic parameter and possibly outcome.