When Donor and Recipient Gender Clash: How Critical is Sex in Heart Transplant Acceptance? Insights from a High-Volume Single-Center Study

All articles of this category (opens in new window) Background: We evaluated the impact of donor-recipient gender mismatch on short- and long-term outcomes after heart transplantation at a German high-volume center. Emphasis is placed on primary graft dysfunction (PGD) requiring ECLS, long-term incidence of cardiac allograft vasculopathy (CAV), rejection, and survival. Additional risk factors influencing graft dysfunction, rejection, and early mortality, alongside gender mismatch, were analyzed. The results aim to support organ allocation decisions amid the ongoing organ shortage and limited availability of gender-matched donors. Methods: We conducted a retrospective analysis (2010–2024) of heart transplant recipients with gender-mismatched donors (biological sex) from our institutional registry. Donor and recipient preoperative data, intraoperative variables (ischemic time, use of ECLS), and postoperative outcomes were analyzed. Descriptive statistics were applied. Categorical data were shown as n (%), continuous as median (range). Odds ratios were calculated using logistic regression. Depending on the data structure, appropriate tests (e.g., Fisher test) were used for comparisons. Results: Among 305 heart transplants performed over 15 years, 69 involved gender-mismatched donor-recipient pairs—55 female-to-male (79.7%) and 14 male-to-female. One-year mortality was 21.7% (15/69), with 93% of deaths occurring in male recipients of female hearts. Primary graft failure was the leading cause of death, followed by sepsis. PGD requiring ECLS occurred in 24 cases (35%). Sixty-two point five percent of the ECLS-patients had a predicted heart mass ratio (PHM ratio) < 0.86, indicating a significant association between size mismatch and ECLS need ( p < 0.05). Furthermore, a notable size mismatch was present in 13 of the 15 patients (86.7%) who died within the first postoperative year. Logistic regression revealed a 4.5-fold increased risk of PGD requiring ECLS in female-to-male transplants when the PHM ratio was < 0.86. An additional seven patients died within 5 years posttransplant, mainly due to chronic rejection, increasing the 5-year mortality to 32%. Among the 47 patients with follow-up, 5 (10.6%) developed CAV within the first year, with no further progression of the disease thereafter. Conclusion: Due to donor shortage, gender-mismatched heart transplants remain unavoidable. However, careful size matching using the PHM ratio may reduce early mortality. With appropriate selection, gender-mismatched transplants can achieve good long-term outcomes. Publication History Article published online: 17 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany