Transcatheter Strategy for Severe Mitral Regurgitation Requiring Percutaneous Ventricular Assist Device Support

Abstract

Background

Data on transcatheter strategies in patients with severe mitral regurgitation (MR) and advanced chronic heart failure requiring Impella support remain limited.

Methods and Results

We retrospectively analyzed 33 patients with severe MR and advanced chronic heart failure requiring Impella support, treated with a transcatheter strategy (n=17) or a conservative strategy (n=16). In an overlapweighted Cox model, the transcatheter strategy was associated with a lower in-hospital mortality rate (hazard ratio, 0.13; 95% confidence interval, 0.03–0.52; P=0.004).

Conclusions

A transcatheter strategy had survival benefit for this high-risk population.

Central Figure.

In patients with advanced chronic heart failure, severe mitral regurgitation (MR) contributes to recurrent decompensation and a poor shortterm prognosis. In these critically ill cases, percutaneous mechanical circulatory support with the Impella device (Abiomed, Danvers, MA, USA) can provide hemodynamic stabilization by actively unloading the ventricle and enhancing cardiac output. Mitral transcatheter edge-to-edge repair (M-TEER) has become an established therapy for some patients with symptomatic MR, but the evidence supporting use of a transcatheter strategy in patients requiring Impella support remains limited. Major M-TEER trials have excluded this high-risk population,^1,2 and available data are limited to case reports or small observational studies.^3,4 Therefore, the clinical impact of this strategy in this population remains unclear.

A retrospective cohort study was conducted using data from a nationwide Japanese registry of percutaneous ventricular assist devices. Patients with severe MR and advanced chronic heart failure who required Impella support for hemodynamic stabilization between February 2020 and December 2023 were included. Patients undergoing major concomitant cardiac interventions or those receiving Impella as a bridge to surgical correction of acute MR were excluded. Patients were managed either with a transcatheter strategy, defined as M-TEER using the MitraClip system (Abbott; Menlo Park, CA, USA) during Impella support, or with a conservative strategy comprising Impella support and intensive medical therapy without mitral valve intervention. The primary outcome was inhospital death. To account for baseline differences between treatment groups, propensity scores were estimated using clinically relevant covariates (age, body mass index, outofhospital cardiac arrest, preImpella heart rate, preImpella systolic blood pressure, lactate and creatinine levels, and left ventricular ejection fraction). Overlap weighting was then applied. Hazard ratios (HRs) for death were calculated using weighted Cox proportional hazards models, with time zero defined as the date of Impella implantation. This study was conducted in accordance with the Declaration of Helsinki and approved by the Institutional Review Board of Sendai Kousei Hospital.

Of the 8,797 patients enrolled in the registry during the study period, 33 with severe MR requiring Impella support met the inclusion criteria. Among them, 17 received a transcatheter strategy and 16 had a conservative strategy; the in-hospital mortality rate was 29% (5/17) and 69% (11/16), respectively. In the unadjusted analyses, the transcatheter strategy was associated with a lower risk of in-hospital death (HR: 0.18, 95% confidence interval [CI]: 0.05–0.58, P=0.004) (Figure A). After overlap weighting, the transcatheter strategy remained associated with a lower risk of in-hospital death compared with the conservative strategy (HR: 0.13, 95% CI: 0.03–0.52, P=0.004) (Figure B).

Figure.

Kaplan–Meier survival curves for in-hospital deaths. (A) Unadjusted survival curves comparing transcatheter and conservative strategies. (B) Overlap-weighted survival curves adjusted for baseline covariates. CI, confidence interval; HR, hazard ratio.

In this nationwide cohort, the transcatheter strategy was associated with a lower inhospital mortality rate than the conservative strategy. The novelty of this study lies in its focused evaluation of a patient population typically excluded from prior clinical trials and for whom therapeutic options remain limited. In patients requiring Impella support, MTEER may function primarily as a rescue or bridge strategy for shortterm hemodynamic stabilization. However, in Japan, MTEER under Impella support is outside approved indications and should be considered an exceptional option reserved for carefully selected patients.

Study Limitations

The small sample size restricts generalizability, and therefore residual imbalance, unmeasured confounding, and selection bias cannot be excluded. Furthermore, immortal time bias and indication bias remain possible given the lack of data on MTEER timing and the indication for Impella support. Detailed information on MR mechanism and concomitant tricuspid regurgitation was also unavailable. Despite these limitations, the findings are exploratory and hypothesisgenerating, and highlight the need for further investigation.

Disclosures

None.

IRB Information

The Institutional Review Board of Sendai Kousei Hospital approved this study (approval number: 6-37).

Data Availability

Data are available from the corresponding author upon reasonable request.