Impact of Anti‐ <scp>HLA</scp> Antibody Desensitization Strategies in Pediatric Heart Transplant Recipients: A <scp>PHTS</scp> ‐ <scp>PHIS</scp> Linkage Analysis

ABSTRACT Purpose Human Leukocyte Antigen (HLA) sensitization can adversely impact heart transplant (HTx) outcomes. We evaluated the effect of panel‐reactive antibody (PRA) and desensitization (DS) strategies on outcomes of pediatric HTx recipients using a unique linkage between clinical registry and administrative databases. Methods The Pediatric Heart Transplant Society (PHTS) registry was queried for all patients transplanted from January 2004 to March 2021 and linked by date of birth, HTx date, and center to the Pediatric Health Information System (PHIS). Class I and II PRA at listing, PRA at HTx, underlying diagnosis, age, gender, and graft loss were abstracted from PHTS. Inpatient DS therapy and associated charges were assessed via PHIS. Listed patients were divided by PRA into Low (&lt; 10%), Medium (&gt; 10% to less than median PRA for sensitized patients), and High (≥ median PRA for sensitized patients) cohorts for both Class I and II PRA. DS‐related change in PRA category pre‐HTx as well as 10‐year graft survival were recorded. Results We linked 3229 HTx recipients (87.5% of total PHTS cohort) with PHIS (45% female, 51% congenital heart disease). Among those with PRA &gt; 10%, median Class I and II PRA was 36% and 48%, respectively. There were 223 High Class I and 191 High Class II patients. Of those with PRA &gt; 10%, 10.8% received some DS therapy, including IVIg, rituximab, bortezomib, and/or plasmapheresis pre‐HTx. DS therapies did not significantly alter absolute PRA or drive a change in PRA category from High to Low ( p &gt; 0.05). Patients with Low PRAs at listing had greater 10‐year graft survival than those with High PRA ( p &lt; 0.05). DS therapy did not improve graft survival among patients who were highly sensitized at listing (Figure). Median pharmacy DS charges were $9.9 K (IQR $3.9 K–$28.4 K). Conclusion Elevated PRA adversely impacts graft survival in pediatric HTx recipients. Efficacy of the studied DS therapies in this limited cohort was inconsistent. In patients highly sensitized at listing, efforts at DS are not associated with improved outcomes. Given cost and morbidity associated with DS, careful assessment of risks and benefits for individual patients is warranted.