Ex-situ machine perfusion of the liver has surmounted traditional limitations associated with static cold storage in the context of organ preservation. This innovative technology has changed the landscape of liver transplantation by mitigating ischemia perfusion injury, offering a platform for continuous assessment of organ quality, and providing an avenue for optimizing use of traditionally marginal allografts. This review summarizes the contemporary clinical applications of machine perfusion devices, and discusses potential future strategies for real-time viability assessment, therapeutic interventions, and modulation of organ function after recovery. Export

The use of normothermic machine perfusion over static cold storage in liver transplantation has been shown to reduce post-transplant risks of early allograft dysfunction, primary nonfunction, and ischemic cholangiopathy, and its increasing use has played a role in the expanded utilization of marginal livers. While studies have demonstrated improved clinical outcomes utilizing normothermic machine perfusion over static cold storage preservation, real-time intraoperative data reflecting the quality and viability of normothermic machine perfusion livers is limited. This retrospective, single-center study compared normothermic machine perfusion vs static cold storage livers in first-time liver transplant recipients through the evaluation of synthetic coagulation function as measured by thromboelastography and conventional coagulation testing. Secondarily, transfusion utilization between the two cohorts were reviewed. 186 liver transplant recipients receiving allografts from donors after circulatory death were included in the study, of which 99 (53%) allografts were preserved in static cold storage, and 87 (47%) allografts were placed on the TransMedics Organ Care System. Study findings showed normothermic machine perfusion livers supported with the TransMedics Organ Care System were associated with increased synthetic coagulation function and less excess fibrinolysis in the post-reperfusion period compared to static cold storage livers, and that these findings were better reflected in real-time with thromboelastography monitoring vs conventional coagulation testing. Following reperfusion, there was a significant decrease in the transfusion of blood products in the normothermic machine perfusion group compared with that in the static cold storage group. Overall, we determined that the use of intraoperative thromboelastography can provide real-time data to assess one aspect of reperfusion liver quality and viability. Export

Background.: Ex vivo machine perfusion (MP) has transformed organ preservation, offering significant benefits in liver transplantation (LT), particularly with high-risk donor grafts. However, adoption in the United States has been limited. We aimed to examine early adoption trends, surgeon perceptions, and barriers to implementing MP in the United States after Food and Drug Administration approval of MP platforms. Methods.: A 23-question electronic survey was distributed to members of the American Society of Transplant Surgeons between October and November 2022, capturing attitudes and practices related to MP adoption. Responses from 96 surgeons representing 77 LT centers across 11 Organ Procurement and Transplantation Network regions were analyzed. Results.: Forty-four respondents (48%) reported having an MP program at their institution. Adoption of MP was significantly more common in high-volume centers and those performing ≥20 donation after circulatory death (DCD) transplants annually (P < 0.001). MP utilization received strong support, with 88% endorsing its use for DCD liver allografts and 82% for donation after brain death allografts. Respondents cited MP’s ability to reduce ischemic cholangiopathy, enable graft repair, and facilitate viability assessment as key benefits. Normothermic MP was preferred for high-risk donor profiles, including DCD grafts, older donors, and steatotic livers, and was associated with an increased willingness to accept medically complex grafts compared with static cold storage. Barriers to MP utilization included program costs, personnel demands, and logistical complexities. Centers with higher proportions of privately insured patients were more likely to adopt MP. Despite these challenges, 84% of respondents expressed interest in future MP adoption. Conclusions.: MP enhances graft utilization and outcomes, particularly for complex and high-risk donor livers, but widespread US adoption requires addressing financial and logistical barriers. Future efforts should focus on refining cost-effectiveness analyses, collaboration with organ procurement organizations and device companies, and developing standardized training to optimize MP integration and maximize its clinical impact on LT.

Despite improvements in kidney transplantation rates, the shortage of donor kidneys remains a critical issue, exacerbated by non-utilization of recovered kidneys due to quality concerns, necessitating advancements in perfusion methods to enhance graft outcomes and usage. Although static cold storage remains the default standard for kidney preservation, newer methods like hypothermic machine perfusion have shown improved outcomes, including reduced delayed graft function and better survival rates. Hypothermic oxygenated machine perfusion and normothermic machine perfusion offer some potential clinical benefits but studies to date have demonstrated mixed results. In the United States, LifePort and the XVIVO’s Kidney Assist Transport are the most popular hypothermic perfusion devices, with NMP devices mostly in trials. Combining perfusion with biomarkers such as mitochondrial flavin mononucleotide, neutrophil gelatinase-associated lipocalin, and osteopontin shows promise in assessing kidney viability and predicting post-transplant outcomes, though further research is also needed. Emphasis on repair biomarkers, such as uromodulin and osteopontin, aims to better predict graft outcomes and develop new therapies. While notable advancements have been made in the use of machine perfusion and viability testing for liver transplantation, additional research with larger sample sizes is essential to substantiate these results and enhance kidney transplantation outcomes.