Pediatric donor hearts are regularly refused for donor quality with limited evidence as to which donor parameters are predictive of poor outcomes. We compare outcomes of recipients receiving hearts previously refused by other institutions for quality with the outcomes of recipients of primarily-offered hearts. Data for recipients aged ≤ 18 and their donors were obtained. Specific UNOS refusal codes were used to place recipients into refusal and non-refusal groups; demographics, morbidity, and mortality were compared. Kaplan-Meier analysis with log-rank test was used to determine differences in graft survival. A multivariable Cox proportional hazards model was constructed to determine independent risk factors for post-operative mortality. From 7/1/2000-4/30/2011, 182 recipients were transplanted and included for analysis. 130 received a primarily-offered heart; 52 received a refused heart. No difference in post-operative complications or graft survival between the two groups (p=0.355) was found. Prior refusal was not an independent risk factor for recipient mortality. Analysis of this large pediatric cohort examining outcomes with quality-refused hearts shows that in-hospital morbidity and long-term mortality for recipients of quality-refused hearts is no different than recipients of primarily-offered hearts, suggesting that donor hearts previously refused for quality are not necessarily unsuitable for transplant and often show excellent outcomes.

Organ transplantation from ABO blood groupincompatible (ABOi) donors requires accurate detection, effective removal and subsequent surveillance of antidonor antibodies. Because ABH antigen subtypes are expressed differently in various cells and organs, measurement of antibodies specific for the antigen subtypes in the graft is essential. Erythrocyte agglutination, the century-old assay used clinically, does not discriminate subtype-specific ABO antibodies and provides limited information on antibody isotypes. We designed and created an ABO-glycan microarray and demonstrated the precise assessment of both the presence and, importantly, the absence of donor-specific antibodies in an international study of pediatric heart transplant patients. Specific IgM, IgG, and IgA isotype antibodies to nonself ABH subtypes were detected in control participants and recipients of ABO-compatible transplants. Conversely, in children who received ABOi transplants, antibodies specific for A subtype II and/or B subtype II antigens-the only ABH antigen subtypes expressed in heart tissue-were absent, demonstrating the fine specificity of B cell tolerance to donor/ graft blood group antigens. In contrast to the hemagglutination assay, the ABO-glycan microarray allows detailed characterization of donor-specific antibodies necessary for effective transplant management, representing a major step forward in precise ABO antibody detection.

Blood group ABH(O) carbohydrate antigens are carried by precursor structures denoted type I-IV chains, creating unique antigen epitopes that may differ in expression between circulating erythrocytes and vascular endothelial cells. Characterization of such differences is invaluable in many clinical settings including transplantation. Monoclonal antibodies were generated and epitope specificities were characterized against chemically synthesized type I-IV ABH and related glycans. Antigen expression was detected on endomyocardial biopsies (n ¼ 50) and spleen (n ¼ 11) by immunohistochemical staining and on erythrocytes by flow cytometry. On vascular endothelial cells of heart and spleen, only type II-based ABH antigens were expressed; type III/IV structures were not detected. Type II-based ABH were expressed on erythrocytes of all blood groups. Group A 1 and A 2 erythrocytes additionally expressed type III/IV precursors, whereas group B and O erythrocytes did not. Intensity of A/B antigen expression differed among group A 1 , A 2 , A 1 B, A 2 B and B erythrocytes. On group A 2 erythrocytes, type III H structures were largely un-glycosylated with the terminal ''A'' sugar a-GalNAc. Together, these studies define qualitative and quantitative differences in ABH antigen expression between erythrocytes and vascular tissues. These expression profiles have important implications that must be considered in clinical settings of ABO-incompatible transplantation when interpreting anti-ABO antibodies measured by hemagglutination assays with reagent erythrocytes.

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Background Previous studies in adults have suggested that donor dopamine treatment may improve recipient outcomes in organ transplantation; in this analysis, we aimed to determine if donor dopamine reduces the incidence of post-operative right heart failure in pediatric heart transplant recipients. Methods Data for recipients aged ≤ 18 transplanted at our institution between 1/1/2000–6/15/2011 and their respective donors were obtained. The presence of postoperative right heart failure was assessed for in all subjects. Donor dopamine dose was stratified into 3 groups: none, low-dose (≤ 5 mcg/kg/min), and high-dose (>5 mcg/kg/min). Logistic regression was used to assess the relationship between donor dopamine dose and recipient right heart failure. Results Of 192 recipients, 34 (18%) experienced postoperative right heart failure. There was no difference in baseline demographics between recipients with and without right heart failure. When controlling for pulmonary vascular resistance index, graft ischemic time, and cardiopulmonary bypass time, donor low-dose dopamine was independently associated with a decreased risk of right heart failure (OR=0.16 [0.04–0.70]; p=0.02); however high-dose DA was neither associated with, nor protective of, RHF (OR: 0.31 [0.06–1.6]; p=0.16). Conclusions Despite advances in perioperative care of the recipient, right heart failure persists as a complication of pediatric heart transplantation. In this study donor pre-treatment with low-dose dopamine is associated with a decreased risk of postoperative right heart failure in pediatric heart recipients. Further studies into this association may be useful in determining the utility of empiric donor pre-treatment with low-dose dopamine.