Comprehensive Analysis of the First 35 Years of Pediatric Heart Transplantation in Sweden.

Background: The first 35 years of pediatric heart transplantation (pHTx) in Sweden were investigated to determine outcomes following listing and transplantation, investigate sub-populations of recipients, and describe the presence of donor-specific antibodies (DSA) in a contemporary cohort.

Methods: Swedish children < 18 years, listed from 1/1/1989 to 31/12/2023, were included. The cohort was split based on the era of transplantation (ERA I: 1989-2008, ERA II: 2009-2023).

Results: A total of 254 children were listed and 185 (72.8%) reached pHTx, with no loss to follow-up. Waiting list duration was 62 days and increased over time, while mortality on the waiting list decreased (30.5% in ERA I, 8.8% in ERA II). Congenital heart disease was the etiology of heart failure in 36.2% of recipients, including 24.9% with univentricular physiology. The frequency of ABO-incompatible transplantations was 9.3% and 8.0% were considered to be at high immunological risk pre-pHTx due to pre-formed HLA-antibodies with mean fluorescence intensity ≥ 5000. Ventricular assist device (VAD) was used in 26.9% of recipients. Long-term survival was not affected by age, heart failure etiology, the use of pre-transplant VAD, or elevated baseline indexed pulmonary vascular resistance. Era of transplantation was a determinant of listing, but not post-pHTx outcome. Survival at 1-, 10-, and 30-year follow-up was 94.5%, 79.4%, and 57.1%, respectively. Of the total de novo DSA burden, 45.9% were HLA-DQ-type specific. Re-transplantation was performed in 5.9% of recipients.

Conclusions: A high quality of care has been achieved in Sweden, despite modest pHTx numbers, in cooperation with the Scandiatransplant organization.