Trials & Tribulations of Liver Transplantation- are trials now prohibitive without surrogate endpoints?

Normothermic Machine Perfusion of Donor Livers for Transplantation in the United States: A Randomized Controlled Trial

OBJECTIVE

To compare conventional low-temperature storage of transplant donor livers [static cold storage (SCS)] with storage of the organs at physiological body temperature [normothermic machine perfusion (NMP)].

BACKGROUND

The high success rate of liver transplantation is constrained by the shortage of transplantable organs (eg, waiting list mortality >20% in many centers). NMP maintains the liver in a functioning state to improve preservation quality and enable testing of the organ before transplantation. This is of greatest potential value with organs from brain-dead donor organs (DBD) with risk factors (age and comorbidities), and those from donors declared dead by cardiovascular criteria (donation after circulatory death).

METHODS

Three hundred eighty-three donor organs were randomized by 15 US liver transplant centers to undergo NMP (n = 192) or SCS (n = 191). Two hundred sixty-six donor livers proceeded to transplantation (NMP: n = 136; SCS: n = 130). The primary endpoint of the study was "early allograft dysfunction" (EAD), a marker of early posttransplant liver injury and function.

RESULTS

The difference in the incidence of EAD did not achieve significance, with 20.6% (NMP) versus 23.7% (SCS). Using exploratory, "as-treated" rather than "intent-to-treat," subgroup analyses, there was a greater effect size in donation after circulatory death donor livers (22.8% NMP vs 44.6% SCS) and in organs in the highest risk quartile by donor risk (19.2% NMP vs 33.3% SCS). The incidence of acute cardiovascular decompensation at organ reperfusion, "postreperfusion syndrome," as a secondary outcome was reduced in the NMP arm (5.9% vs 14.6%).

CONCLUSIONS

NMP did not lower EAD, perhaps related to the inclusion of lower-risk liver donors, as higher-risk donor livers seemed to benefit more. The technology is safe in standard organ recovery and seems to have the greatest benefit for marginal donors.

Outcomes of livers from donation after circulatory death donors with extended agonal phase and the adjunct of normothermic regional perfusion

The liver performs important functions that are essential for life. If the liver fails, patients will die unless they receive a new liver from a donor (transplant). Unfortunately, there are not enough livers for everyone and some patients die while waiting for a suitable organ. This article describes a novel technique that allows resuscitation and testing of a potential donor liver so that more patients can safely receive a transplant.

Novel Composite Endpoint for Assessing Outcomes in Liver Transplantation: Arterial and Biliary Complication-Free Survival

Transplant and patient survival are the validated endpoints to assess the success of liver transplantation (LT). This study evaluates arterial and biliary complication-free survival (ABCFS) as a new metric. ABC, considered as an event, was an arterial or biliary complication of Dindo-Clavien grade ≥III complication dated at the interventional, endoscopic, or surgical treatment required to correct it. ABCFS was defined as the time from the date of LT to the dates of first ABC, death, relisting, or last follow-up (transplant survival is time from LT to repeat LT or death). Following primary whole LT (n = 532), 106 ABCs occurred and 99 (93%) occurred during the first year after LT. An ABC occurring during the first year after LT (overall rate 19%) was an independent factor associated with transplant survival (hazard ratio [HR], 3.17; P < 0.001) and patient survival (HR, 2.7; P = 0.002) in univariate and multivariate analyses. This result was confirmed after extension of the cohort to split-liver graft, donation after circulatory death, or re-LT (n = 658). Data from 2 external cohorts of primary whole LTs (n = 249 and 229, respectively) confirmed that the first-year ABC was an independent prognostic factor for transplant survival but not for patient survival. ABCFS was correlated with transplant and patient survival (ρ = 0.85 [95% CI, 0.78-0.90] and 0.81 [95% CI, 0.71-0.88], respectively). Preoperative factors known to influence 5-year transplant survival influenced ABCFS after 1 year of follow-up. The 1-year ABCFS was indicative of 5-year transplant survival. ABCFS is a reproducible metric to evaluate the results of LT after 1 year of follow-up and could serve as a new endpoint in clinical trials.