Related Experiment Video
Updated: Nov 6, 2025
Author Spotlight: Enhancing Graft Viability Assessment Through Quantitative Metrics and Innovative Reservoir Systems
Published on: August 2, 2024
Bridging With Extracorporeal Membrane Oxygenation Under the New Heart Allocation System: A United Network for Organ
Taylor Nordan1, Andre C Critsinelis2, Shant H Mahrokhian1
1Department of Cardiac Surgery (T.N., S.H.M., F.Y.C., G.S.C., M.K.), Tufts Medical Center, Boston, MA.
Insights
The new heart allocation system significantly improves survival for patients on extracorporeal membrane oxygenation (ECMO) bridging to transplantation. This system reduces waitlist times and preoperative complications, leading to better post-transplant outcomes.
Area of Science:
- Cardiology
- Transplantation Medicine
- Medical Technology
Background:
- The impact of the revised donor heart allocation system on survival for patients bridged with venous-arterial extracorporeal membrane oxygenation (ECMO) was previously unknown.
- The updated system prioritizes ECMO-supported candidates for heart transplantation.
Purpose of the Study:
- To evaluate the effect of the new donor heart allocation system on post-transplant survival.
- To assess changes in waitlist outcomes and preoperative comorbidities for heart transplant candidates bridged with ECMO.
Main Methods:
- Analysis of the United Network for Organ Sharing database for adult patients bridged to single-organ heart transplantation with ECMO (October 2006-February 2020).
- Comparison of outcomes between the new and old allocation systems using Kaplan-Meier estimates, Cox proportional hazards models, and propensity score matching.
Main Results:
- The new system halved waitlist time (5 vs. 10 days) and reduced rates of prior cardiac surgery and preoperative ventilation.
- 180-day survival was significantly higher under the new system (90.2%) compared to the old system (69.6%).
- The new system was an independent predictor of improved post-transplant survival and reduced waitlist mortality or deterioration.
Conclusions:
- Heart transplant recipients bridged with ECMO under the new allocation system experience improved 180-day survival and fewer preoperative comorbidities.
- The new system has led to significant improvements in waitlist outcomes, including reduced mortality and increased likelihood of transplantation.
Background:
The effect of the new donor heart allocation system on survival following bridging to transplantation with venous-arterial extracorporeal membrane oxygenation remains unknown. The new allocation system places extracorporeal membrane oxygenation-supported candidates at the highest status.
Methods:
The United Network for Organ Sharing database was queried for adults bridged to single-organ heart transplantation with extracorporeal membrane oxygenation from October 2006 to February 2020. Association between implementation of the new system and recipient survival was analyzed using Kaplan-Meier estimates, Cox proportional hazards models, and propensity score matching.
Results:
Of 364 recipients included, 173 and 191 were transplanted under new and old systems, respectively. Compared with the old system, waitlist time was halved under the new system (5 versus 10 days, P<0.01); recipients also demonstrated lower rates of prior cardiac surgery (32.9% versus 44.5%, P=0.03) and preoperative ventilation (30.6% versus 42.4%, P=0.02). Unadjusted 180-day survival was 90.2% (95% CI, 84.7%-94.2%) and 69.6% (95% CI, 62.6%-76.1%) under the new and old systems, respectively. Cox proportional hazards analysis demonstrated listing and transplantation under the new system to be an independent predictor of post-transplant survival (adjusted hazard ratio, 0.34 [95% CI 0.20-0.59]). Propensity score matching demonstrated a similar trend (hazard ratio, 0.36 [95% CI, 0.19-0.66]). Candidates listed under the new system were significantly less likely to experience waitlist mortality or deterioration (subhazard ratio, 0.38 [95% CI, 0.25-0.58]) and more likely to survive to transplant (subhazard ratio, 4.29 [95% CI, 3.32-5.54]).
Conclusions:
Recipients transplanted following extracorporeal membrane oxygenation bridging to transplantation under the new system achieve greater 180-day survival compared with the old and demonstrate less preoperative comorbidity. Waitlist outcomes have also improved significantly under the new allocation system.
