Transcatheter strategy for severe mitral regurgitation requiring percutaneous ventricular assist device support

Background/Introduction Severe mitral regurgitation (MR) in advanced chronic heart failure can lead to refractory haemodynamic deterioration requiring Impella support. Evidence for a transcatheter strategy in this population remains limited. Purpose To evaluate short-term outcomes of a transcatheter strategy versus a conservative strategy in this high-risk population. Methods We performed a retrospective cohort study using the nationwide Japanese Registry for Percutaneous Ventricular Assist Devices. Consecutive patients with severe MR and advanced chronic heart failure requiring Impella (2.5, CP, 5.0, or 5.5) for haemodynamic stabilisation between 1 February 2020 and 31 December 2023 were included. A transcatheter strategy was defined as transcatheter edge-to-edge repair (MitraClip) during Impella support, whereas a conservative strategy consisted of Impella support with intensive medical therapy without mitral intervention. The primary outcome was in-hospital mortality. Propensity scores were estimated using logistic regression including prespecified baseline covariates: age, body mass index, out-of-hospital cardiac arrest, pre-Impella heart rate, pre-Impella systolic blood pressure, lactate, creatinine, and left ventricular ejection fraction. Overlap weighting was applied and treatment effects were assessed using an overlap-weighted Cox model with robust standard errors. Results A total of 33 patients met the inclusion criteria (transcatheter strategy n=17; conservative strategy n=16). Covariate balance was achieved after overlap weighting (all standardised mean differences <0.20). In-hospital mortality was 29% (5/17) with the transcatheter strategy and 69% (11/16) with the conservative strategy. In the primary overlap-weighted analysis, the transcatheter strategy was associated with a significantly lower risk of in-hospital mortality (hazard ratio 0.24; 95% confidence interval 0.08–0.74; P=0.013). Results were consistent in sensitivity analyses using LASSO-adjusted Cox modelling (hazard ratio 0.29; 95% confidence interval 0.08–0.97) and restricted mean survival time at 60 days (difference 22 days; 95% confidence interval 5–39). Conclusion(s) Among patients with severe MR and advanced chronic heart failure requiring Impella support, a transcatheter strategy was associated with substantially lower in-hospital mortality than a conservative strategy. These findings suggest that a transcatheter strategy during Impella support may be a reasonable therapeutic option in carefully selected patients with refractory haemodynamic compromise.