A current era analysis of ABO incompatible listing practice and impact on outcomes in young children requiring heart transplantation

Abstract

BACKGROUND: Heart transplantation from ABO incompatible (ABOi) donors has evolved into a progressively accepted therapy in young children. We assessed the recent practice of ABOi listing impact on waitlist and post-transplant outcomes. METHODS: Using the Pediatric Heart Transplant Society registry, we compared clinical presentation, waitlist parameters, and post-transplant survival of children < 2 years of age listed for ABOi vs ABO compatible (ABOc) heart transplant between January 2010 and June 2018 with sub-analysis of blood group O recipients. RESULTS: Among 2,039 patients, ABOi listing increased significantly with time from 49% (2010) to 72% (2017). ABOi-listed patients had lower age and body surface area, and higher proportion of congenital heart disease, mechanical ventilation, and high urgency status (all p < 0.01). Use of mechanical circulatory support was similar between groups. Of 1,288 patients reaching transplant, 239 (18.6%) received an ABOi organ (15%−40%/year). Death while waiting, removal from the waitlist, and waitlist survival were similar between groups. Time to transplant was significantly shorter for ABOi listing in blood group O patients (p < 0.02), approaching significance (p = 0.057) for all blood groups. Post-transplant survival was similar except for lower survival of patients listed ABOc but transplanted ABOi. These patients showed increasing need for mechanical circulatory support and high urgency listing while waiting. CONCLUSIONS: In the current era, primary listing for ABOi heart transplant has become routine for the majority of children < 2 years old, resulting in shorter waitlist time, especially in blood group O. Posttransplant survival is similar despite ABOi-listed children still showing a higher risk profile.

Pediatric heart transplantation: Year in review 2020

“…Importantly, ABOi PHT did not affect early or long-term survival or the incidence of rejection and led to a significant decrease in waitlist time for blood group O recipients. These observations were further validated by Urschel and colleagues 13 using the Pediatric Heart Transplant Society registry. These authors also demonstrated that children initially listed for compatible transplantation and changed to ABOi had higher 1-year mortality, which likely reflects precarious clinical status, worsening clinical condition, and need for extracorporeal membrane oxygenation.…”

Transplantation for Congenital Heart Disease: Focus on the Impact of Functionally Univentricular Versus Biventricular Circulation

“…24,25 We attribute this to the fact that prior studies, including a large, recent, multicenter study of the Pediatric Heart Transplant Study and/or Society, have only assessed posttransplant survival of ABO blood type incompatible patients as a whole without stratifying by diagnoses. 26 Therefore, they may not have identified ABO blood type incompatibility as a risk factor specific to patients with CHD such as in this study. There are studies which note a predilection toward listing more ill children as ABO blood type incompatible, and it may be desirable to transplant the patient sooner, despite higher posttransplant risk of mortality.…”

Partial heart transplantation can ameliorate donor organ utilization

“…29 ABO-incompatible OHT has been successful among children and neonates and is now common practice in children under 2 years of age, increasing from 49% in 2010 to 72% in 2017. 23,29,30 An important implication of ABO-incompatible OHTs becoming commonplace is that it alleviates the undue burden of competition for donor organs among patients with blood group O. This is reflected in a significantly shorter waitlist time for blood group O patients when ABO-incompatible organs are accepted.…”