Impact of Residual Transmitral Mean Pressure Gradient on Outcomes after Mitral Transcatheter Edge-to-Edge Repair

Background There is conflicting evidence regarding the effect of residual transmitral mean pressure gradient (TMPG) after mitral transcatheter edge-to-edge repair (M-TEER). Different TMPG cutoffs have been employed in prior studies with varying results. Objectives The purpose of this study was to examine the association between residual TMPG and M-TEER outcomes. Methods Consecutive patients undergoing M-TEER at our institution between 2014 and 2022 were included and divided based on quartiles of predischarge TMPG. Outcomes were assessed using Kaplan-Meier analysis and Cox proportional hazard models. We performed subgroup analyses according to mitral regurgitation (MR) mechanism. The primary outcome was all-cause mortality or heart failure hospitalization. Results We included 283 patients (age 76.7 ± 10.8 years, 42.8% women, 78.4% Caucasian, and baseline TMPG 2.4 ± 1.3 mm Hg). Higher baseline TMPG was a predictor of increased TMPG after M-TEER (coefficient 0.60 [95% CI: 0.40-0.70]; P < 0.001). In comparison with predischarge TMPG quartiles 1 to 3, those in quartile 4 (7.0 ± 1.1 mm Hg) had an increased risk of 3-year all-cause mortality or heart failure hospitalization (adjHR: 1.53 [95% CI: 1.03-2.26]; P = 0.034), as well as all-cause mortality alone (adjusted HR [adjHR]: 1.68 [95% CI: 1.09-2.60]; P = 0.020). Among patients with primary MR, similar findings were seen for the composite end point (adjHR: 2.08 [95% CI: 1.15-3.77]; P = 0.016), and all-cause mortality (adjHR: 2.70 [95% CI: 1.40-5.19]; P = 0.003). However, this association did not reach statistical significance in secondary MR. Conclusions In this single-center study, higher residual TMPG after M-TEER was associated with worse outcomes at intermediate- to long-term follow-up. The effect was mainly driven by increased mortality especially in patients with primary MR. Operators should strive to lower residual TMPG before the conclusion of the procedure.