Multicenter Evaluation of a National Organ Sharing Policy for Highly Sensitized Patients Listed for Heart Transplantation in Canada

Abstract

Conclusion:Thyroid hormone use can have important implications for organ selection and cardiac function before and after transplantation. Protocols vary widely with respect to why and how to use and wean thyroid hormone. We believe there should be more detailed reporting of thyroid hormone use for future studies to ensure appropriate donor management. ( 585)Purpose: Brain-stem-death (BSD) causes cardiac injury and dysfunction that is sometimes reversible. The optimum time after BSD at which to assess the function of donor hearts is unknown. We hypothesized that a longer interval may be associated with a higher transplantation rate due to improved function. Methods: Data on adult DBD solid organ donors were obtained retrospectively from the UK Transplant Registry for the period 1 January 2008 to 31 December 2012. Donors above the age of 65 with a past history of cardiothoracic disease, consent for heart donation was refused or whose cause of death was myocardial infarction were excluded. The time when fixed dilated pupils were first noted in the donor was considered as the time of BSD. Retrieval was defined as the time when the abdominal organs were perfused. Results: BSD to retrieval duration was available for 1,839 donors. Of these donors, 461 (25%) donated their heart. The median (IQR) BSD to retrieval duration was 35.6 hours (27.6, 48.7). BSD to retrieval durations differed (p< 0.0001) depending on the time of day when BSD was diagnosed (separated in to four quartiles). A multivariate logistic regression was then performed. Donor age, blood group, gender, cause of death, heart rate, body mass index, past history of hypertension, cardiac arrest and use of prednisolone were all found to influence the probability of donation. Adjusting for these factors, there was evidence to suggest that the BSD to retrieval duration had a non-linear effect upon heart donation (p= 0.047).The effect was such that, longer durations were associated with a higher probability of donation. However, the odds ratio for the probability of heart donation began to plateau at a value of 1 after approximately 1.5 days suggesting that durations beyond this have no impact on the chance of donation. Analysis of a subset of donors attended by a cardiothoracic retrieval team showed a similar pattern. Conclusion: This data suggest that time interval from BSD to retrieval influences the heart retrieval rate. A longer time interval may allow the heart to recover from the BSD induced injury. When the sole reason for decline a donor heart is poor function, a period of further observation and optimisation up to 1.5 days should be considered.

Current Desensitization Strategies in Heart Transplantation

“…Developing a prioritization policy, as has been implemented in Canada ( 9 ), may be of value but is limited by the lack of standardization across HLA labs in the US, differences in what constitutes an unacceptable antigen, and difficulties defining an optimal cut-off. Furthermore, this approach may foster hesitancy to pursue robust immunomodulatory desensitization strategies with the potential to improve long-term outcomes.…”

“…Underlying etiology and magnitude of the HLA antibody response may contribute to this heterogeneity as all non-responders in this study were women. Contemporary studies of perioperative plasmapheresis with IVIG also suggest that post-transplant rejection is common, likely because this approach does not address the underlying immune response ( 9 , 109 , 110 ).…”

“…In the United States, sensitized transplant candidates do not receive priority status on the waitlist ( 8 ). While policy change is one approach, prioritization can be a double-edged sword, resulting in hesitancy to develop robust, mechanistically driven desensitization strategies with the potential to improve post-transplant outcomes ( 9 ). Instead, prioritization may favor peri-transplant antibody management approaches that temporize the situation but do not modulate the underlying immune response.…”

Canadian Cardiovascular Society/Canadian Cardiac Transplant Network Position Statement on Heart Transplantation: Patient Eligibility, Selection, and Post-Transplantation Care

“…The status 4S system has shown effective expansion of the donor pool with satisfactory posttransplantation outcomes. 80 Revision of the 4S listing status category will yield a change to give ranking priority to the highest cPRA in descending fashion; cPRA 100% higher priority than 99%, followed by 98%, 90%-97%, and 80%-89% (Supplemental Tables S1 and S2). Values and preferences.…”