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

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.

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).

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.

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