BACKGROUND: Transplant programs may submit exception requests to upgrade a listed patient’s priority, often anticipating a higher likelihood of accepting marginal or high-risk donor organs. This study explores whether exception request status is associated with increased risk tolerance in organ acceptance.
METHODS: We conducted a retrospective analysis using data from the Scientific Registry of Transplant Recipients (SRTR), focusing on adult patients (≥18 years) listed for heart transplantation. Statistical analyses were performed using SAS/STAT 14.1. Descriptive statistics summarized demographic and clinical variables. Baseline characteristics were compared between recipients with and without exception requests. Primary analysis: Mixed-effects linear regression was used to model continuous risk scores, incorporating a random intercept for transplant center and adjusting for recipient factors including age, sex, mechanical support devices, comorbidities, left ventricular hypertrophy, cardiac output, race, and HCV status. Secondary analysis: Logistic regression assessed the likelihood of accepting high-risk donor organs, defined by thresholds at the 75th, 80th, and 90th percentiles.
RESULTS: Among 20,543 heart transplant recipients, the average candidate age was 53.3 years (±12.8), with 72.9% male and 27.1% female. Racial distribution included 68.5% Caucasian, 25.6% Black, 4.0% Asian, 0.5% Multiracial, and 1.4% Other. Hispanic ethnicity accounted for 11.1% of candidates. Donor candidates had an average age of 33.0 years (±10.2) and an average ejection fraction of 61.8% (±6.8). The average recipient length of stay was 24.6 days (±27.4). Further analyses will explore stratified predictors of mortality, donor characteristics, and diagnostic indicators such as ejection fraction, wait time, and hospitalization duration.
CONCLUSION: This study aims to determine whether exception requests are associated with increased risk tolerance in organ acceptance, potentially informing transplant center practices and allocation policies.

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Analytical, Diagnostic and Therapeutic Techniques and Equipment
Cardiology
Cardiovascular Diseases
Diseases
Internal Medicine
Medical Specialties
Medicine and Health Sciences
Surgical Procedures, Operative