Outcomes of transcatheter edge-to-edge repair for atrial functional mitral regurgitation

BACKGROUND: The prognostic benefits of transcatheter edge-to-edge repair (TEER) remain unclear in patients with atrial functional mitral regurgitation (AFMR). AIMS: We aimed to investigate the clinical outcomes of TEER for patients with AFMR. METHODS: We retrospectively classified functional mitral regurgitation (FMR) patients undergoing TEER into those with AFMR or ventricular FMR (VFMR). A residual MR <= 1+ at discharge was considered optimal mitral regurgitation (MR) reduction, and an elevated mean mitral valve pressure gradient (MPG) was defined as an MPG >= 5 mmHg at discharge. The primary outcome was a composite of all-cause mortality and hospitalisation due to heart failure within one year. RESULTS: Of 441 FMR patients, 125 patients were considered as having AFMR. Residual MR <= 1+ was associated with a lower risk of the composite outcome in both AFMR and VFMR patients, while an MPG >= 5 mmHg was associated with a higher risk of the composite outcome in patients with AFMR but not with VFMR. AFMR patients with residual MR <= 1+ and an MPG >= 5 mmHg, as well as those with residual MR >1+, had a higher incidence of the composite outcome than those with residual MR <= 1+ and an MPG <5 mmHg (50.7%, 41.8%, and 14.3%, respectively; p<0.001). This association was consistent after adjustment for clinical and echocardiographic characteristics. CONCLUSIONS: An MR reduction to <= 1+ following TEER was associated with a lower risk of clinical outcomes in patients with AFMR, while an MPG >= 5 mmHg was related to a higher risk of clinical outcomes. Optimal MR reduction by TEER may have potential benefits on the prognosis of patients with AFMR, although the prognostic benefit may be attenuated by an elevated MPG.