BTS 2012 Report – ABO-incompatible transplantation: cardiac and liver

by Maria Dalby reporting on the presentation by Lori West, University of Alberta, Toronto, Canada and Andrew Burroughs, Royal Free Hospital, London.  ABO-incompatible transplantation is already a clinical reality in renal transplantation, and is increasingly used in other organ transplantation activity as well. In a parallel session entitled ABOi Transplantation, Professor Lori West, director of heart transplantation research at the University of Alberta in Toronto, Canada, presented recent data on ABOi heart transplantation, and Professor Andrew Burroughs, consultant hepatologist at the Royal Free Hospital in London, outlined the current status of ABOi liver transplantation.

The introduction of ABO-incompatible heart transplantation has been slow compared with other organ transplantation disciplines; the fact that there is no effective ‘dialysis equivalent’ in case of graft failure and the susceptibility of cardiac grafts to antibody-mediated damage has meant that historically, clinicians have been reluctant to cross the ABO barrier. A review of ABO-incompatible heart transplants published in 1990 showed that the outcomes were very poor in cases of inadvertent ABO-incompatible heart transplantation.¹ However, emerging antibody removal technologies using plasmapheresis or immunoadsorption together with enhanced immunosuppression protocols have turned ABO-incompatible heart transplantation into a realistic treatment option. To date, most of the activity has been in the comparatively safe infant population. Around 200 ABO-incompatible infant heart transplants were carried out between 1996 and 2012; more than 50 of these were performed in the UK (27 in Newcastle and 26 in London). A number of ABO-incompatible heart transplants have also been carried out in older children, and a Swedish centre has performed two ABO-incompatible heart transplants on adult patients with favourable results. Overall, the ‘mid-term’ clinical outcomes have been shown to be similar in ABO-incompatible and ABO-compatible patients.²

ABO-incompatible liver transplantation is another relatively rare activity for largely the same reasons as for  the heart, i.e. poor outcomes reported during the early stages³ and the lack of emergency treatment alternatives in case of graft failure. However, recent data from the UNOS registry on patients undergoing liver transplantation for acute liver failure shows that graft survival has improved in recent years in all age groups relative to compatible liver transplantations, to a greater extent than could be attributable to an era effect.⁴ For infants and children up to the age of 17 years, there was indeed no statistically significant difference in graft survival. The European Liver Transplant Registry (ELTR) has reported data on 63,947 adult patients who underwent liver transplantation between January 1988 and December 2010.⁵ Of these, 710 were ABO-incompatible, and 437 of these were transplanted due to chronic liver failure. Again, no statistically significant difference was seen in graft survival between the incompatible and compatible transplants; multivariate Cox regression analysis shows that the risk of graft failure is approximately 43% greater with an incompatible liver compared with an identical liver.

As in the case of ABO-incompatible heart transplantation, the use of immune-adsorption techniques for removing anti-A and anti-B antibodies has had some encouraging results in recent reports.^6,7 Summarising, Professor Burroughs stressed that there is now sufficient evidence to allow ABO-incompatible liver transplantation under controlled clinical conditions, and that the allocation strategies should be adjusted to accommodate this.

References:

1. Cooper DK. A clinical survey of cardiac transplantation between ABO blood group-incompatible recipients and donors. Transplant Proc 1990; 22(4): 1457
2. Dipchand AI, Pollock BarZiv SM, et al. Equivalent outcomes for pediatric heart transplantation recipients: ABO-blood group incompatible versus ABO-compatible. Am J Transplant 2010; 10(2): 389-397
3. Farges O, Kalil AN, Samuel D, et al. The use of ABO-incompatible grafts in liver transplantation: a life-saving procedure in highly selected patients. Transplantation 1995; 59(8): 1124-1133
4. Stewart ZA, Locke JE, Montgomery RA, et al. ABO-incompatible deceased donor liver transplantation in the United States: a national registry analysis. Liver Transpl 2009; 15(8): 883-893
5. European Liver Transplant Registry, 2011
6. Markiewicz-Kijewska M, Kaliciński P, Teisseyre J, et al. Liver transplantation with ABO incompatible graft under immunoadsorption protocol–case report. Ann Transplant 2010; 15(4): 68-71
7. Saliba F, Ichaï P, Azoulay D, et al. Successful long-term outcome of ABO-incompatible liver transplantation using antigen-specific immunoadsorption columns. Ther Apher Dial 2010; 14(1): 116-123