Comments on "Regulations and Procurement Surgery in DCD Liver Transplantation: Expert Consensus Guidance From the International Liver Transplantation Society".

Abstract

To the Editor: We read with great interest the article by Hessheimer et al titled “Regulations and Procurement Surgery in DCD Liver Transplantation: Expert Consensus Guidance From the International Liver Transplantation Society.”1 The authors summarize relevant literature and provide guidelines for donation after circulatory death (DCD) liver transplant procurement on behalf of the International Liver Transplantation Society (ILTS). Our research group recently emphasized the variations in DCD organ procurement policies in the United States with a national organ procurement organization (OPO) survey.2 We discovered tremendous disparities across regions that frequently diverged from American Society for Transplant Surgeons (ASTS) recommendations for DCD procurement and the latest consensus in the literature. It is paramount to optimize graft utilization and outcomes to meet the high demand for transplantable organs and growing waitlist. We commend the authors for their important contributions. We highlight the role of asystolic wait time in DCD liver procurement that was not addressed in the work and provide observations on DCD liver transplant (LT) and machine perfusion (MP) from the United States. Our OPO survey underscored the variations in the mandatory asystolic observation period. Despite current ASTS recommendation of a 2-min waiting time, there is little standardization across institutions that vary between 2 and 5 min. Similarly, other publications have demonstrated the lack of standardization in the declaration of circulatory death.3 Additional guidance by the ILTS on these topics would optimize DCD liver procurement process to further reduce warm ischemic times and ultimately improve patient outcomes. Currently, 11 high-volume transplant centers perform nearly half (46.3%) of all DCD LT in the United States.4 However, recent changes to the allocation policies will result in wider sharing of DCD organs and increase distribution to lower volume centers. This will undoubtedly place greater emphasis on procedures to maintain outcomes, such as broader use of hypothermic machine perfusion and normothermic machine perfusion in LT. Machine perfusion with LT has shown promising results in the United States. One investigation discovered no difference in patient survival in ex vivo MP despite substantially longer CIT.5 MP has the potential to significantly improve DCD liver procurement and reduce discard rates. In 2019 alone, 1945 potential DCD livers were not transplanted including 306 grafts, which were discarded after recovery. The trend of increasing DCD LT in the United States has been accompanied with 30% discard rate compared with 7.1% for DBD LT.5 Furthermore, one center reported that only 47.9% of DCD liver offers resulted in a successful procurement, compared with 92.3% for DBD.6 Nasralla et al demonstrated 50% reduction in graft injury, discard, and postreperfusion injury rates in an normothermic machine perfusion clinical trial.7 A publication by the Groningen group on dual hypothermic oxygenated MP highlighted lower rates of nonanastomotic biliary strictures, postreperfusion syndrome, and early graft dysfunction compared with static cold storage in DCD LT.8 MP could remarkably impact the American LT waitlist by increasing potential DCD livers that are transplanted. We congratulate Hessheimer et al on their valuable contributions. We are pleased to see the growing support for procurement procedures such as withdrawal of life support treatment in the operating room and premortem heparin administration. Despite strong surgeon preference for both of these, our survey revealed that 26 OPO did not have specific regulations on the location of withdrawal of life support treatment and 3 OPO prohibited heparin use.2,3 We hope that the ILTS recommendations lead to updates in DCD procurement protocol and regulations to comply with the latest evidence in the literature. We hope to see more analyses of liver perfusion solutions and the various additives. We anticipate similar best practice guidance by the ASTS for normothermic and hypothermic regional perfusion in liver transplantation in the near future. Reduction in variable DCD liver recovery will be tremendously impactful in increasing the utilization of DCD livers and reducing graft discard rates.