Center volume effect on acute cellular rejection and outcomes in pediatric lung transplant recipients

Acute cellular rejection (ACR) is common after lung transplant (LTx). We sought to determine if transplant center volume affected ACR-related outcomes in children after LTx. The United Network for Organ Sharing (UNOS) Registry was queried for patients 5LTxs/year), medium volume center (MVC) (>1≤5 LTxs/year), and low volume center (LVC) (≤1LTxs/year). 1320 patients were enrolled into the study; 269 (20.4%) did not experience ACR. The ACR cohort was older (median 14 [11-16] vs 13 [7-16] years, p < 0.001), female (65.3% vs 57.3%, p = 0.016), had cystic fibrosis (62.3% vs 45.5%, p < 0.001), and had a higher lung allocation score (37.3 [34.6-47.8] vs 35.8 [33-42.6], p = 0.029). The ACR cohort trended (p = 0.06) towards lower survival at 5-year (37% vs 47%) and 10-year (25% vs 34%) post-LTx. Among children at HVCs, ACR occurred in 17% of recipients (n = 98/574), compared to 18.5% (n = 73/395) at MVCs and 27% (n = 100/369) at LVCs. Children treated for ACR at HVCs had higher survival than LVCs at 5-years (52% vs 29%) and 10-years (36% vs 15%) (p < 0.001) but similar survival to MVCs at 5-years (52% vs 43%) and 10-years (36% vs 24%) (p = 0.081). No survival differences were detected in MVCs vs LVCs (p = 0.14). ACR treated within the first post-LTx year influence survival of children. ACR incidence was lowest at higher volume centers whereas post-ACR treatment survival outcomes were also superior.