Prognostic impact of being underweight in patients undergoing mitral TEER: The OCEAN-Mitral registry.

Aims: Mitral transcatheter edge-to-edge repair (M-TEER) is a valid treatment option for severe mitral regurgitation (MR), necessitating accurate risk stratification of M-TEER candidates for effective patient selection, optimal periprocedural care and improved long-term outcomes. The body mass index (BMI) is a simple and practical prognostic index, and the obesity paradox has been widely reported.

Methods and results: Between April 2018 and June 2021, 2149 patients undergoing M-TEER were registered in the prospective multicentre registry and classified into three groups: underweight (BMI < 18.5 kg/m²), normal weight (18.5 ≦ BMI < 25 kg/m²) and overweight and obese (25 kg/m² ≦ BMI). The impact of underweight on the all-cause, cardiovascular and non-cardiovascular mortality following M-TEER was evaluated [follow-up duration: 436 (363-733) days]. The participants (median BMI: 21.1 kg/m²) were categorized as underweight (n = 450, 20.9%), normal weight (n = 1409, 65.6%) and overweight and obese (n = 290, 13.5%). Compared with the other two groups, the underweight group exhibited several negative prognostic factors, including older age, frailty, no dyslipidaemia, hypoalbuminaemia, residual MR and non-home discharge. Underweight patients had the highest rate of all-cause, cardiovascular and non-cardiovascular mortality, whereas those in the other two groups were similar. As per the multivariate analysis, underweight itself was associated with all-cause mortality (hazard ratio: 1.52, 95% confidence interval: 1.17-1.97, P = 0.009) and cardiovascular mortality (hazard ratio: 1.45, 95% confidence interval: 1.04-2.01, P = 0.028).

Conclusions: Underweight patients had the highest mortality rate after M-TEER. Comorbidities, residual MR, discharge disposition and underweight status were correlated with postprocedural outcome.