Background: Antibody-mediated rejection (AMR) is of great relevance when assessing therapies to improve survival for pediatric heart transplant (HT). Biopsy (EMB) is the most specific means for diagnosing AMR. This study explores the impact on survival and adverse events after treated rejection (TRej) in children with AMR on EMB (any pAMR 1h or i, 2, or 3) vs acute cellular rejection (ACR). Methods: Children in the Pediatric HT Study transplanted between 1/2015-6/2022 who survived ≥2 weeks and had at least 1 TRej with EMB data were included. Survival was compared after 1st TRej with any AMR to pure ACR. Secondary outcomes of infection, malignancy, and cardiac allograft vasculopathy (CAV) after 1st TRej were assessed. Risk factors for mortality after AMR were identified using Cox proportional hazard modeling. Results: Among 3172 HT recipients, 906 (29%) had at least 1 TRej. Of these, 697 (77%) had EMB data to determine the presence of AMR. At the 1st TRej episode, 261 (37%) children had features of AMR. Median time to 1st Trej was earlier in those with AMR vs ACR, 0.11 vs 0.29 yrs. p=0.001. Survival after 1st TRej with AMR was worse than ACR in the 1st yr post HT (A); however, survival was similar when 1st TRej occurred after year 1 (B) (Figure 1 A, B). The AMR group had higher panel reactive antibody at HT, more congenital heart disease (CHD), and more had ABO incompatible HT (all p<0.05). There was no difference in time to 1st infection, malignancy, or CAV between those with treated AMR vs ACR. Multivariate predictors of graft loss after AMR were younger age, CHD, and ECMO at HT, and hemodynamic compromise at TRej (all p<0.048). Neither AMR grade nor concomitant ACR was associated with graft loss after AMR. Conclusion: This is the largest analysis of contemporary outcomes of EMB-confirmed AMR in pediatric HT. Findings underscore the impact of early AMR on graft loss and the need for tailored therapies. Similar time to infection after AMR vs ACR is notable since immune targets of therapy often differ.
Background: Mortality through single-ventricle palliation remains high and the effect of the timing of stage 2 palliation (S2P) is not well understood. We investigated current practice patterns in the timing of S2P across two professional societies and compared them to actual practice patterns from two databases of patients who underwent S2P. Methods: A ten-question survey was distributed to the members of the Congenital Heart Surgeons’ Society (CHSS) and the European Congenital Heart Surgeons’ Association (ECHSA). Results were summarized using descriptive statistics. Surgeon-reported preferences were compared to clinical data from the CHSS Critical Left Ventricular Outflow Tract Obstruction (LVOTO) Registry and the Pediatric Heart Network Single Ventricle Reconstruction (SVR) database. Results: Overall, 38% (88 of 232) of surgeons from 74 institutions responded, of which 70% (62 of 88) were CHSS members and 30% (26 of 88) were ECHSA members. Surgeons reported performing S2P at a median of five months after stage 1 (interquartile range [IQR]: 4.5-6), with no difference between CHSS and ECHSA surgeons. Surgeons reported performing nonelective S2P at a median of 4.5 months after stage 1 (IQR: 3.5-5.5), again with no difference by society. No difference existed between the surgeon-reported preferences and patient data in the Critical LVOTO and SVR databases for the timing of elective (5 vs 5.1 vs 5.3 months, P = .19) or nonelective S2P (4.5 vs 4.6 vs 4.2 months, P = .06). Conclusion: There was a remarkable lack of variation in surgeon preferences regarding the timing of S2P. This may represent a natural standardization of practice across congenital heart surgery, which is notable, given the current lack of guidelines regarding the timing of S2P.
