ABO Incompatible Listing in Early Childhood Results in Earlier Transplantation and Equal Post-Transplant Survival Despite Predominant Use in Sicker Patients

Purpose In early childhood, heart transplantation (Tx) can safely be performed using organs from an ABO incompatible (ABOi) donor. This approach broadens the accessible donor pool for the recipient and should impact wait list mortality and waiting time, as shown in single center settings. We sought to identify clinical characteristics of ABOi listed patients (Pt) and impact of ABOi listing on waiting list parameters. Methods The large multi-center registry of the Pediatric Heart Transplant Society captured intention to accept an ABOi donor at listing since 2010. We compared children < 2 years of age listed for ABOi vs. ABO compatible (ABOc) Tx between 2010-2017. We performed a sub-analysis for blood group O children. Results 1083 patients were listed ABOi and 819 ABOc. ABOi-listed patients had significantly lower age and BSA (p<0.0001); higher proportion of congenital heart disease (p<0.01), higher urgency listing status (p<0.0001) and otherwise similar demographics including frequency of mechanical circulatory support (MCS). Blood group (BG) O was more common in ABOi and AB in ABOc listed patients. Death while waiting, removal from the waitlist and overall wait list survival were similar between groups, however, ABOi had significantly shorter time to Tx (mean 71.5 days vs. 93.5 days for ABOc, p<0.03), especially in BG O patients (p<0.01). Post-Tx survival up to 6 years was similar with the exception of Patients listed ABOc but transplanted ABOi, who had lower post-Tx survival. These patients showed a significant increase in the need for MCS between listing and Tx (p=0.04). Conclusion In the current era patients primarily listed for ABOi still show a higher risk profile compared to ABOc listed patients. Independently, post-Tx survival is equal and wait times are reduced, especially for BG O children. A switch in listing from ABOc to ABOi is associated with worse post-Tx survival probably due to clinical deterioration of the patients while waiting. In early childhood, heart transplantation (Tx) can safely be performed using organs from an ABO incompatible (ABOi) donor. This approach broadens the accessible donor pool for the recipient and should impact wait list mortality and waiting time, as shown in single center settings. We sought to identify clinical characteristics of ABOi listed patients (Pt) and impact of ABOi listing on waiting list parameters. The large multi-center registry of the Pediatric Heart Transplant Society captured intention to accept an ABOi donor at listing since 2010. We compared children < 2 years of age listed for ABOi vs. ABO compatible (ABOc) Tx between 2010-2017. We performed a sub-analysis for blood group O children. 1083 patients were listed ABOi and 819 ABOc. ABOi-listed patients had significantly lower age and BSA (p<0.0001); higher proportion of congenital heart disease (p<0.01), higher urgency listing status (p<0.0001) and otherwise similar demographics including frequency of mechanical circulatory support (MCS). Blood group (BG) O was more common in ABOi and AB in ABOc listed patients. Death while waiting, removal from the waitlist and overall wait list survival were similar between groups, however, ABOi had significantly shorter time to Tx (mean 71.5 days vs. 93.5 days for ABOc, p<0.03), especially in BG O patients (p<0.01). Post-Tx survival up to 6 years was similar with the exception of Patients listed ABOc but transplanted ABOi, who had lower post-Tx survival. These patients showed a significant increase in the need for MCS between listing and Tx (p=0.04). In the current era patients primarily listed for ABOi still show a higher risk profile compared to ABOc listed patients. Independently, post-Tx survival is equal and wait times are reduced, especially for BG O children. A switch in listing from ABOc to ABOi is associated with worse post-Tx survival probably due to clinical deterioration of the patients while waiting.