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Updated: Jun 23, 2026

A Modified Method for Heterotopic Mouse Heart Transplantion
Published on: June 23, 2014
High Rate of Transplantation Before Review of Status Exception Requests Among Adult Heart Transplant Candidates
Daniel J Ahn1,2,3, Toshihiro Nakayama1,3, Antony Attia1,3
1Department of Surgery (D.J.A., T.N., A.A., K.S.), Stanford University, CA.
Insights
Over 25% of heart transplant candidates receive transplants before their exception requests reach review boards. This highlights concerns regarding the fairness of retrospective reviews in organ allocation.
Area of Science:
- Cardiology
- Transplant Surgery
- Health Policy
Background:
- The US heart allocation system grants immediate status upgrades for exception requests.
- Applications are reviewed retrospectively by regional review boards (RRBs).
- The frequency of transplants during this retrospective review period is unknown.
Purpose of the Study:
- To determine the rate of heart transplantation during the period between exception application submission and RRB receipt.
- To assess the impact of application approval or denial on transplant rates during this interval.
- To estimate the number of patients potentially bypassed due to transplants occurring during exception request review.
Main Methods:
- Analysis of adult heart transplant candidates listed between October 2018 and May 2025 using the Scientific Registry of Transplant Recipients.
- Assessment of time from exception application submission to RRB receipt.
- Stratification of transplant rates by eventual application outcome (approved/denied).
Main Results:
- 11,508 candidates submitted exception requests; 7.9% were denied at least once.
- Median time from upgrade to RRB receipt was 3 days.
- 26.1% of candidates received transplants before RRB application receipt (19.1% of those denied, 26.7% of those approved).
- Transplants in candidates with ultimately denied exceptions bypassed over 11,000 potential recipients.
Conclusions:
- Over 25% of patients with status exception requests receive heart transplants before RRB review.
- This raises significant fairness concerns about retrospective review processes in donor heart allocation.
- The current system may not ensure equitable access to transplants for all waitlisted patients.
Background:
In the US heart allocation system, when transplant centers submit applications for status exceptions to increase waitlist priority, patients obtain the requested status upgrades immediately while their applications are sent to the regional review boards (RRBs) and reviewed retrospectively. How often transplants occur during this period is unknown.
Methods:
Using the Scientific Registry of Transplant Recipients, we identified all adult heart transplant candidates listed between October 18, 2018, and May 31, 2025, with submitted applications for status exceptions. We assessed (1) the time elapsed between submission of exception applications and their receipt by the RRBs and (2) the rate of heart transplantation during this travel time, stratified by whether the applications were eventually approved or denied. Additionally, we estimated how many listed patients were skipped by candidates who received transplants with exceptions that were ultimately denied.
Results:
138 transplant centers submitted status exception requests on behalf of 11 508 adult candidates during the study period, of whom 913 (7.9%) received a denial at least once. The median time from obtaining status upgrades to application receipt by the RRBs was 3 days. Three thousand seven out of 11 508 (26.1%) patients received transplants before the RRBs even received their applications, with 174 (19.1%) among 913 with eventual denials and 2833 (26.7%) among 10 595 with approvals. The cumulative incidence of heart transplantation before application receipt for eventual denials was 19.1% (95% CI, 16.6%-21.7%), and that for approvals was 27.2% (95% CI, 26.4%-28.0%; P<0.001) at 2 weeks. Candidates who received transplants despite being denied exceptions bypassed more than 11 thousand potential transplant recipients.
Conclusions:
More than 25% of patients with status exception requests receive heart transplants before their applications are even received by their RRBs, raising significant concerns about the fairness of retrospective review of exception requests for the allocation of donor hearts.
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