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Published on: August 2, 2024
Impact of Left Ventricular Unloading on Outcome of Heart Transplant Bridging With Extracorporeal Membrane Oxygenation
Vasiliki Gregory1, Kenji Okumura2, Ameesh Isath3
1New York Medical College Valhalla NY USA.
Insights
Left ventricular unloading during veno-arterial extracorporeal membrane oxygenation (VA-ECMO) support for heart transplant (HT) candidates did not affect outcomes. Routine LV unloading may not be necessary for all HT patients on VA-ECMO.
Area of Science:
- Cardiology
- Transplant Surgery
- Mechanical Circulatory Support
Background:
- The new heart allocation policy prioritizes veno-arterial extracorporeal membrane oxygenation (VA-ECMO)-supported heart transplant (HT) candidates.
- Left ventricular (LV) unloading during VA-ECMO is increasingly supported, but its impact on HT outcomes is unknown.
Purpose of the Study:
- To investigate the effect of LV unloading on transplant outcomes in patients bridged to HT with VA-ECMO.
- To compare outcomes between VA-ECMO alone and VA-ECMO with LV unloading.
Main Methods:
- Retrospective analysis of 624 patients on VA-ECMO at the time of HT from the United Network for Organ Sharing database (Oct 2018–Mar 2023).
- Patients were divided into VA-ECMO alone (N=384) and VA-ECMO with LV unloading (N=240) groups.
- Subanalysis compared Impella (N=106) and intra-aortic balloon pump (N=134) for LV unloading.
Main Results:
- One-year survival was comparable between VA-ECMO alone (88.0%) and LV unloading (90.4%) groups (P=0.92).
- LV unloading was not associated with posttransplant mortality (HR, 0.92; P=0.70).
- Different LV unloading methods showed similar 1-year survival rates.
Conclusions:
- LV unloading did not impact waitlist or posttransplant survival in patients bridged to HT with VA-ECMO.
- The mode of LV unloading also did not affect outcomes.
- A tailored approach is important, as routine LV unloading may not be universally necessary for HT candidates on VA-ECMO.
Background:
The new heart allocation policy places veno-arterial extracorporeal membrane oxygenation (VA-ECMO)-supported heart transplant (HT) candidates at the highest priority status. Despite increasing evidence supporting left ventricular (LV) unloading during VA-ECMO, the effect of LV unloading on transplant outcomes following bridging to HT with VA-ECMO remains unknown.
Methods And Results:
From October 18, 2018 to March 21, 2023, 624 patients on VA-ECMO at the time of HT were identified in the United Network for Organ Sharing database and were divided into 2 groups: VA-ECMO alone (N=384) versus VA-ECMO with LV unloading (N=240). Subanalysis was performed in the LV unloading group: Impella (N=106) versus intra-aortic balloon pump (N=134). Recipient age was younger in the VA-ECMO alone group (48 versus 53 years, P=0.018), as was donor age (VA-ECMO alone, 29 years versus LV unloading, 32 years, P=0.041). One-year survival was comparable between groups (VA-ECMO alone, 88.0±1.8% versus LV unloading, 90.4±2.1%; P=0.92). Multivariable Cox hazard model showed LV unloading was not associated with posttransplant mortality after HT (hazard ratio, 0.92; P=0.70). Different LV unloading methods had similar 1-year survival (intra-aortic balloon pump, 89.2±3.0% versus Impella, 92.4±2.8%; P=0.65). Posttransplant survival was comparable between different Impella versions (Impella 2.5, versus Impella CP, versus Impella 5.0, versus Impella 5.5).
Conclusions:
Under the current allocation policy, LV unloading did not impact waitlist outcome and posttransplant survival in patients bridged to HT with VA-ECMO, nor did mode of LV unloading. This highlights the importance of a tailored approach in HT candidates on VA-ECMO, where routine LV unloading may not be universally necessary.
