Left atrial volume index and outcome after transcatheter edge-to-edge valve repair for secondary mitral regurgitation.

Aims: To investigate the role of left atrial volume index (LAVi) in patients with secondary mitral regurgitation (SMR) undergoing transcatheter edge-to-edge mitral valve repair (TEER).

Methods And Results: Outcomes were evaluated in SMR patients of a European multicentre registry according to baseline LAVi. Main analysis was performed for all-cause mortality; residual mitral regurgitation (MR) and New York Heart Association (NYHA) class improvement were analysed for patients available. A total of 1074 patients were included with a median LAVi (interquartile range) of 58 ml/m (46-73). Postprocedural reduction of MR grade to ≤2+ was similar across LAVi quintiles, ranging 91%-96% (p = 0.26). Symptomatic benefit (≥1 NYHA class improvement) also did not differ by LAVi quintiles (61%-68% of patients) (p = 0.66). The risk of mortality increased by 23%-42% in the four upper quintiles compared to the bottom quintile (LAVi <42 ml/m ). The hazard ratio (HR) of mortality was 1.35 (95% confidence interval [CI] 1.02-1.78, p = 0.035) associated with a LAVi >42 ml/m , which was attenuated after multivariable adjustment (HR 1.18, 95% CI 0.83-1.67, p = 0.36). A significant interaction was found for MR severity and pulmonary hypertension, with an increased risk of death associated with enlarged LAVi in patients with inframedian effective regurgitant orifice area (HR 1.99, 95% CI 1.06-3.74, p = 0.032) and in patients with systolic pulmonary pressure ≤50 mmHg (HR 1.67, 95% CI 1.02-2.75, p = 0.042) in multivariable analysis.

Conclusion: Procedural success and symptomatic benefit were high throughout the whole range of LAVi. The prognostic impact of left atrial enlargement was relevant in patients with less severe SMR and without pulmonary hypertension, reinforcing the need to identify patients in the early course of backward congestion to achieve good long-term outcome after TEER.