Multicenter Experience of ABO-Incompatible Pediatric Cardiac Transplantation

Abstract

Although ABO blood group incompatible cardiac transplantation in neonates and infants reduces waiting list mortality without compromising outcome, the technique has not been adopted by all centers, and to date Toronto remains the only center to have published results from a large case series. We present a review of ABO-incompatible heart transplantation in the United Kingdom (UK) where current recipient selection criteria differ somewhat from those used in the United States (US) and Canada. Between February 2000 and November 2006, 21 ABO-incompatible cardiac transplants were performed in children aged 2-40 months (median 10.0). Immunosuppression followed standard regimens. Pretransplant donor-specific isohemagglutinins of >1:4, (the UNOS cutoff), were present in five patients and reduced by plasma exchange. After transplantation, 19/21 recipients demonstrated persisting deficiency of donor-specific isohemagglutinins. Significant donor-specific isohemagglutinins levels were detected repeatedly in 2/21 recipients who have shown no clinical or biopsy evidence of rejection. All recipients survive without retransplantation and there have been no episodes of humoral rejection. We conclude it is possible for other centers to replicate the excellent results achieved in Toronto and that ABO-incompatible transplantation may be performed successfully in some patients beyond infancy with established isohemagglutinin production providing preoperative antibody removing strategies are used.

Pushing the boundaries: The current status of ABO-incompatible cardiac transplantation

“…64 This was more often seen in patients who were older at the time of transplant or had pre-existing HLA sensitization, and was not associated with an increased risk of AMR or death. This supports other reports from the UK 37 and Sweden, 65 which showed re-accumulation of donor blood group-specific isohemagglutinins, but without graft damage. Thus, in these patients, B-lymphocyte elimination does not occur and alternative mechanisms of graft tolerance need to be invoked.…”

“…6,37,40,47,53 There appears to be no difference in longer term survival, nor an increased incidence of cardiac allograft vasculopathy, post-transplant lymphoproliferative disease (PTLD) or renal dysfunction. 35,48 A recent multicenter study using the Pediatric Heart Transplant Study (PHTS) database analyzed 85 ABOi cardiac transplants.…”

“…37,39,40 Recent Canadian data demonstrated a decrease in wait listing mortality for infants under 6 months of age from 58% to 7%, with ABOi transplants making up 40% of transplants in this age group. 40 There was the additional benefit of a reduction in unused donor organs.…”

“…15,35,37 Isohemagglutinin titers should be measured regularly in the immediate post-transplant period but correlate poorly with clinical, echocardiographic or pathologic signs of AMR. One explanation for this may be that antibodies bind to the graft and thereby decrease the circulating titer.…”

Outcome of shared care for pediatric cardiac transplantation between two nations with different health care systems

“…14,15 The capacity of younger patients to undergo ABO incompatible transplantation has also meant that this young patient cohort has a significantly increased chance of receiving an organ. [16][17][18] Patients with high panel reactivity were not contraindicated from transplantation. 19 Although this report focuses on the shared care provided locally, the good results in the 2 UK transplant centers (with no peri-operative deaths) is noteworthy.…”