Liver transplantation remains a crucial treatment for patients with end-stage liver disease, yet the persistent organ shortage in the United States highlights the need for expanding donor pools. One underutilized source is donation after circulatory death (DCD), primarily due to historically poor outcomes, including ischemic cholangiopathy (IC) and early allograft dysfunction. This study, conducted at the University of Colorado Hospital, evaluates the effectiveness of thoracoabdominal normothermic regional perfusion (TA-NRP) in improving DCD liver transplantation (DCD LT) outcomes compared to static cold storage (SCS).
A retrospective analysis of 162 DCD liver transplants was conducted from January 2017 to August 2024, with 97 performed using TA-NRP and 79 via SCS. Of these, 150 recipients reached six-month follow-ups (NRP: 86, SCS: 74). The study’s primary outcome was the incidence of IC at six months, while secondary outcomes included donor risk factors, allograft survival, and biochemical assessments of accepted versus declined NRP livers.
Key Findings:
- Reduction in Ischemic Cholangiopathy (IC): The incidence of IC was significantly lower in the NRP group compared to the SCS group (1.2% vs. 9.5%, p = 0.03). This suggests that NRP mitigates bile duct injury, one of the main concerns associated with DCD liver transplantation.
- Higher-Risk Donor Utilization: The study found that NRP facilitated the use of higher-risk donor livers. NRP donors were significantly older (median age 41 vs. 33 years, p < 0.001) and had higher donor risk indices (2.44 vs. 2.17, p = 0.002). Despite these factors, transplant success rates remained comparable to lower-risk SCS transplants.
- Better Biochemical and Perfusion Parameters in Accepted Livers: Biochemical assessments of accepted NRP livers showed lower peak lactate levels (8.8 vs. 10.1 mg/dL, p = 0.004), higher biliary bicarbonate levels (22.5 vs. 10.2 mEq/L, p = 0.004), and better perfusion stability compared to declined NRP livers. These findings suggest that bile and lactate levels could serve as predictive markers of liver viability.
- Comparable 12-Month Graft and Patient Survival: Despite the use of higher-risk donors, there were no significant differences in patient survival (97% NRP vs. 95% SCS, p = 0.43) or graft survival (96% NRP vs. 95% SCS, p = 0.75) at 12 months, reinforcing NRP’s viability as a method for preserving DCD livers.
- Improved Organ Utilization Rates: TA-NRP significantly increased organ utilization per donor compared to SCS (3.36 vs. 1.91 organs per donor, p < 0.001), supporting its role in improving the overall efficiency of organ recovery from DCD donors.
- Reduction in Perioperative Complications and ICU Stays: Patients receiving NRP livers required fewer intraoperative blood transfusions, spent fewer days in the ICU, and had shorter hospital stays compared to SCS recipients. These findings suggest that NRP mitigates ischemia-reperfusion injury, leading to better immediate post-transplant outcomes.
Implications for Clinical Practice:
TA-NRP appears to be a game-changer in DCD liver transplantation by improving allograft viability and reducing IC rates. Its ability to expand the donor pool by making high-risk livers viable while maintaining excellent short-term and long-term outcomes makes it a valuable technique. The study’s findings encourage further research into refining NRP viability assessment criteria, including the potential role of bile chemistry and lactate clearance trends.
Limitations:
The study was retrospective and limited to a single center, which may impact generalizability. Additionally, while six months is a relevant endpoint for IC assessment, longer follow-ups are necessary to confirm the durability of these findings.
Study Ranking = 4.5/5. High-quality study with strong retrospective data, a large sample size, and clinically relevant findings. However, it lacks randomized controlled trials for definitive conclusions.
