Assessing Infectious Burden in Heart Transplant Recipients: A Comparative Study of Allocation Status

Introduction: Adult heart transplants continue to rise, with infections remaining a major cause of morbidity and mortality. The 2018 UNOS policy update prioritizes sicker patients for transplant. While this strategy improves short-term survival, the impact of infection-related complications remains unclear. Therefore, the purpose of this study was to compare infection related complications within the first 90 days post-transplant between recipients listed as high and low allocation status.


Methods: This single-center, retrospective study evaluated adult heart transplant recipients between February 2019 and June 2024. Patients were grouped by allocation status: 1–2 (high) vs. 3, 4, and 6 (low). Status 5 recipients were excluded due to multiorgan transplant. The two primary outcomes, assessed within the first 90 days post-transplant, were: (1) the percentage of patients who developed at least one culture-proven infection, and (2) the cumulative number of days of antibiotic exposure, defined as any day on which at least one non-prophylactic antibiotic was administered. Positive cultures were further categorized by causative organism and site of infection. Antibiotic exposure was also evaluated based on activity against methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (PSAR).


Results: Among 148 patients (70 high, 78 low allocation), the high group had more brain-dead donors (87% vs. 67%, p< 0.05), mechanical circulatory support (79% vs. 36%, p< 0.05), and longer pre-transplant hospitalization (23 vs. 1 day, p< 0.05). Infection rates were similar between high-allocation and low-allocation groups (21% v. 22%, p=1). Higher rates of pneumonia were seen in the low-allocation group (0% vs. 9%, p=0.01), while no differences were noted in causative organisms. The median days of antibiotic exposure did not differ between the two groups, 12 [4-25] v. 9 [4-25], p=0.23. There were no differences in patients receiving an anti-MRSA (14% v. 13%, p=0.81) or PSAR (10% v. 13%, p=0.62) antibiotic course.


Conclusions: Despite greater pre-transplant acuity, high-allocation heart transplant recipients had similar infection rates and antibiotic exposure within 90 days post-transplant compared to lower-allocation recipients.