Predictors and clinical impact of worsening left ventricular ejection fraction after mitral transcatheter edge-to-edge repair

BACKGROUND: Little is known about the effects of left ventricular ejection fraction (LVEF) worsening after transcatheter edge-to-edge valve repair (TEER) for mitral regurgitation (MR). AIMS: This study investigated the predictors and clinical impact of LVEF worsening after TEER for primary MR (PMR) and secondary MR (SMR). METHODS: This study included 2,019 patients (493 with PMR and 1,526 with SMR) undergoing successful TEER (postprocedural MR grade ≤2+) in the OCEAN-Mitral registry. The patients were categorised into worsened LVEF (wEF), defined as a relative decrease of >12.9% in LVEF at discharge, and preserved LVEF (pEF). The serial changes in left ventricular (LV) function at 1 year were also evaluated. RESULTS: Following TEER, 657 (32%) patients demonstrated wEF. The pEF group demonstrated both decreased left ventricular end-diastolic volumes (LVEDV) and end-systolic volumes (LVESV), and the wEF group showed significantly increased LVESV at discharge. Higher LVEF, larger LVEDV, higher B-type natriuretic peptide levels, and moderate/severe aortic regurgitation predicted wEF. Compared with baseline, the wEF group still demonstrated lower LVEF (46% to 43%; p<0.001) but significantly increased stroke volume (48 mL to 53 mL; p=0.001) at 1 year. The incidence of death or heart failure hospitalisation was similar between the wEF and pEF groups (hazard ratio 1.14, 95% confidence interval: 0.72-1.80; p=0.84) and also in patients with PMR and SMR. CONCLUSIONS: LVEF worsening after TEER was not uncommon and was caused by the increased LVESV. LV volumes and some patient-specific factors predicted worsened LVEF which was not associated with long-term clinical outcomes. OCEAN-Mitral registry: UMIN-CTR ID: UMIN000023653.