Liver transplantation across ABO blood groups

Pediatric Liver Transplantation Across the ABO Blood Group Barrier: Is It an Obstacle in the Modern Era?

BACKGROUND

The initial experience with ABO incompatible (ABOi) orthotopic liver transplantations (OLTs) was dismal. In the current study, we investigated whether ABOi pediatric OLTs could achieve acceptable patient outcomes. The option for ABOi transplantation is vital because critically ill children have limited access to donor liver allografts.

STUDY DESIGN

Kaplan-Meier and multivariate Cox analysis was performed on data collected from 13,179 pediatric OLT recipients in the United Network for Organ Sharing database, including 540 ABOi recipients. We also analyzed 18 pediatric recipients of ABOi OLTs at Texas Children's Hospital. Recipients were divided into 2 groups: transplanted between 1987 to 2002 (remote era) and 2002 to 2013 (modern era).

RESULTS

Analysis revealed 4 main points. First, there was a significant (p < 0.01) improvement in ABOi OLT survival in the modern era. Second, threshold analysis revealed superior outcomes (p < 0.01) for OLT recipients younger than 2 years of age. Third, survival outcomes for ABOi and ABO-identical OLTs were the same for recipients younger than 2 years: ABOi was 91.8% (1 year) and 88.4% (5 year), and ABO identical was 91.5% (1 year) and 86.7% (5 year) (p = 0.94). Lastly, we found identical OLT results when analyzing our own institutional experience. To date, there has been a 92.9% survival rate in the modern era compared with 75% in the remote era. All recipients younger than 2 years (n = 9) are still alive, compared with 78% of those older than 2 years.

CONCLUSIONS

This analysis revealed a significant improvement in the survival of ABOi liver transplant recipients in the modern era. Importantly, ABOi liver transplantation can be performed in recipients younger than 2 years of age with equivalent outcomes compared with ABO-identical recipients.

ABO-incompatible deceased donor liver transplantation in the United States: a national registry analysis

In the United States, ABO-incompatible liver transplantation (ILT) is limited to emergent situations when ABO-compatible liver transplantation (CLT) is unavailable. We analyzed the United Network for Organ Sharing database of ILT performed from 1990-2006 to assess ILT outcomes for infant (0-1 years; N = 156), pediatric (2-17 years; N = 170), and adult (> 17 years; N = 667) patients. Since 2000, the number of ILT has decreased annually, and there has been decreased use of blood type B donors and increased use of blood type A donors. Furthermore, ILT graft survival has improved for all age groups in recent years, beyond the improved graft survival attributable to era effect based on comparison to respective age group CLT. On matched control analysis, graft survival was significantly worse for adult ILT as compared to adult CLT. However, infant and pediatric ILTs did not have worse graft survival versus age-matched CLT. Adjusted analyses identified age-specific characteristics impacting ILT graft loss. For infants, transplant after 2000 and donor age < 9 years were associated with reduced risk of ILT graft loss. For pediatric patients, female recipient sex and donor age > 50 years were associated with increased risk of ILT graft loss. For adults, life support, repeat transplant, split grafts, and hepatocellular carcinoma were associated with increased risk of ILT graft loss. The current study identifies important trends in ILT in the United States in the modern immunosuppression era, as well as specific recipient, donor, and graft characteristics impacting ILT graft survival that could be utilized to guide ILT organ allocation in exigent circumstances. Liver Transpl 15:883-893, 2009. (c) 2009 AASLD.

Use of "O" blood group liver donors for nonidentical recipients: does this represent a double penalty for "O" blood group candidates?

Candidates for liver transplantation with AB blood group remain on the waiting list for shorter times than candidates with O blood group. To investigate the reasons of this phenomenon, we analyzed data concerning deceased donors, liver transplant candidates, and liver first transplants performed in the United States during the period 2003 to 2004. The percentage of deceased donors with blood group O was higher than that of candidates on the waiting list with the identical blood group (P < .05). On the other hand, for blood groups A, B, and AB an opposite situation was observed: the percentages of deceased donors were significantly lower compared to those candidates with the identical blood group (A blood group, P < .05; B and AB blood groups, P < .001). When the number of grafts from deceased donors was compared with the number of those effectively transplanted, a negative difference for O blood group recipients was found (ie, transplanted livers < harvested livers) and a positive one for AB blood group (transplanted livers > harvested livers) were found. Since disease progression and causes of acute liver failure, including primary nonfunction and hepatic artery thrombosis leading to retransplantation were similar among the various blood groups, we concluded that the shorter waiting time for AB patients in the pre-MELD era was due to the use of compatible livers to the detriment of group O recipients.