Expanding the donor pool: Donation after circulatory death and living liver donation do not compromise the results of liver transplantation

Transplant Outcomes of Donation After Circulatory Death Livers Recovered With Versus Without Premortem Heparin Administration

Premortem heparin administration during donation after circulatory death (DCD) organ recovery is thought to optimize liver perfusion. However, premortem heparinization is not universally practiced in the United States and limited data exist regarding its utility. US registry data were accessed between January 1, 2003, and March 10, 2017, and 2 cohorts were ascertained: (1) DCD donor livers recovered for transplantation (n = 5495) and (2) liver-only adult transplant recipients of DCD livers (n = 3754). Exclusions were donor unknown heparin status (n = 40), positive donor hepatitis B surface antigen (n = 4) and hepatitis C virus (n = 120) serologies, and for the outcomes analysis, livers placed outside the United States (n = 10). Discard rates and graft outcomes were examined from cohorts 1 and 2, respectively. Of 5495 DCD livers recovered for transplant, 589 (10.7%) donors did not receive premortem heparin (no heparin) and the remaining 4906 (89.3%) received heparin (heparin). Liver discard was similar between the no heparin (30.6%) and heparin groups (30.8%; P = 0.90). Heparin status was not associated with liver discard on multivariate analysis (adjusted odds ratio, 0.97; 95% confidence interval [CI], 0.80-1.18 P = 0.76). The cumulative probability of overall graft survival was lower in the no heparin group relative to the heparin group (P < 0.05), and this finding persisted on multivariate analysis. No heparin group transplants had an 18% higher hazard of overall graft failure compared with those that received heparin (adjusted hazard ratio, 1.18; 95% CI, 1.01-1.38; P < 0.05). In conclusion, organ recovery heparin administration status was not associated with liver discard. Failure to pretreat organ donors with premortem heparin correlates with worse liver transplant graft survival compared with heparin-treated livers.

Clinical Implications of Donor Warm and Cold Ischemia Time in Donor After Circulatory Death Liver Transplantation

The use of donation after circulatory death (DCD) liver allografts has been constrained by limitations in the duration of donor warm ischemia time (DWIT), donor agonal time (DAT), and cold ischemia time (CIT). The purpose of this study is to assess the impact of longer DWIT, DAT, and CIT on graft survival and other outcomes in DCD liver transplants. The Scientific Registry of Transplant Recipients was queried for adult liver transplants from DCD donors between 2009 and 2015. Donor, recipient, and center variables were included in the analysis. During the study period, 2107 patients underwent liver transplant with DCD allografts. In most patients, DWIT and DAT were <30 minutes. DWIT was <30 minutes in 1804 donors, between 30 and 40 minutes in 248, and >40 minutes in 37. There was no difference in graft survival, duration of posttransplant hospital length of stay, and readmission rate between DCD liver transplants from donors with DWIT <30 minutes and DWIT between 30 and 40 minutes. Similar outcomes were noted for DAT. In the multivariate analysis, DAT and DWIT were not associated with graft loss. The predictors associated with graft loss were donor age, donor sharing, CIT, recipient admission to the intensive care unit, recipient ventilator dependence, Model for End-Stage Liver Disease score, and low-volume transplant centers. Any CIT cutoff >4 hours was associated with increased risk for graft loss. Longer CIT was also associated with a longer posttransplant hospital stay, higher rate of primary nonfunction, and hyperbilirubinemia. In conclusion, slightly longer DAT and DWIT (up to 40 minutes) were not associated with graft loss, longer posttransplant hospitalization, or hospital readmissions, whereas longer CIT was associated with worse outcomes after DCD liver transplants.

Effect of the Selective NLRP3 Inflammasome Inhibitor mcc950 on Transplantation Outcome in a Pig Liver Transplantation Model With Organs From Donors After Circulatory Death Preserved by Hypothermic Machine Perfusion

BACKGROUND

We investigated whether the outcome of organs from donors after circulatory death (DCD) can be improved by the addition of mcc950 to the perfusate of the hypothermic machine perfusion (HMP) system and intravenous mcc950 injection after transplantation in a pig liver transplantation model.

METHODS

Thirty-six healthy Bama mini pigs randomized into 3 groups. All the DCD livers were preserved in an HMP system after 2 hours of simple cold storage. In HMP-Postop group, mcc950 was added to the perfusate; in the control group and Postop group, the perfusate was normal LPS. After transplantation, the pigs in the Postop group and HMP-Postop group were intravenously administered 3 mg/kg mcc950, at the time of reperfusion and on day 2 and day 3 after transplantation. During the 3-day follow-up period, general operative characteristics, and serological markers and histological features related to ischemia reperfusion injury were examined.

RESULTS

The HMP-Postop group suffer the lightest ischemia reperfusion injury (IRI), and functioned best after transplantation. Model for the Early Allograft Function Score (predictor of long-term survival), degree of injury in the hepatocytes and rate of apoptosis was lowest in the HMP-Postop group. Further, in the HMP-Postop group, the nucleotide-binding domain leucine-rich repeat containing family pyrin domain containing 3 inflammasome pathway activation was lowest, and the level of IL-1β was lowest. Postop group functioned better than control group, but not comparable with HMP-Postop group.

CONCLUSIONS

The outcome of DCD organs can be improved by the addition of mcc950 to the perfusate of the HMP system and intravenous injection of mcc950 after transplantation.

Recent advances in liver transplantation for cancer: The future of transplant oncology

Liver transplantation is widely indicated as a curative treatment for selected patients with hepatocellular carcinoma. However, with recent therapeutic advances, as well as efforts to increase the donor pool, liver transplantation has been carefully expanded to patients with other primary or secondary malignancies in the liver. Cholangiocarcinoma, colorectal and neuroendocrine liver metastases, and hepatic epithelioid haemangioendothelioma are amongst the most relevant new indications. In this review we discuss the fundamental concepts of this ambitious undertaking, as well as the newest indications for liver transplantation, with a special focus on future perspectives within the recently established concept of transplant oncology.

Improved Graft Survival After Liver Transplantation for Recipients With Hepatitis C Virus in the Direct-Acting Antiviral Era

Highly effective direct-acting antiviral (DAA) therapy has transformed outcomes of liver transplantation in hepatitis C virus (HCV) patients. We examined longer-term outcomes in HCV-positive recipients in the DAA era and analyzed the Scientific Registry of Transplant Recipients for primary adult, single-organ, nonfulminant liver transplant recipients in the United States from January 1, 2008 to June 30, 2018. Graft loss was compared among HCV-positive liver transplant recipients who received either an HCV-negative or HCV-positive donor (donor [D]-/recipient [R]+; D+/R+) and HCV-negative liver transplant recipients who received a HCV-negative donor (D-/R-). The groups were further divided between the pre-DAA and DAA eras. There were 52,526 patients included: 31,193 were D-/R- patients; 18,746 were D-/R+ patients; and 2587 were D+/R+ patients. The number of D-/R+ transplants decreased from 2010 in 2008 to 1334 in 2017, with this decline particularly noticeable since 2015. D-/R+ patients in the DAA era (n = 7107) were older, had higher rates of hepatocellular carcinoma, and lower Model for End-Stage Liver Disease scores than those in the pre-DAA era. Graft survival improved for all recipients in the DAA era but improved most dramatically in HCV-positive recipients: D-/R+ 1-year survival was 92.4% versus 88.7% and 3-year survival was 83.7% versus 77.7% (DAA versus pre-DAA era, respectively) compared with D-/R- 1-year survival of 92.7% versus 91.0% and 3-year survival of 85.7% versus 84.0% (DAA versus pre-DAA era, respectively). The magnitude of improvement in 3-year graft survival was almost 4-fold greater for D-/R+ patients. The 3-year survival for D+/R+ patients was similar to HCV-negative patients. In conclusion, the number of liver transplants for HCV has decreased by more than one-third over the past decade. Graft survival among HCV-positive recipients has increased disproportionately in the DAA era with HCV-positive recipients now achieving similar outcomes to non-HCV recipients.

Challenges and future developments in liver transplantation

Liver transplantation (LT) has become the treatment of choice for a wide range of liver diseases in both adult and pediatric patients. Until recently, the largest proportion of LT in adults, were performed in patients with hepatitis C (HCV) related cirrhosis. The recent availability of safe and effective direct antiviral agents to cure HCV infection in almost all patients whatever the HCV genotype and severity of liver disease, will reduce the need for LT in this category of recipients. Thus, it is presumed that in the next 1 to 2 decades HCV related liver disease will diminish substantially, whereas non-alcoholic steato-hepatitis (NASH) will correspondingly escalate as an indication for LT. The greatest challenges facing LT remain the limited supply of donor organs, and the need for chronic immunosuppression, which represent the true obstacles to the greater application and durable success of the LT procedure. This review aimed to highlight, in different sections, the main open issues and future developments in LT. These will be focused to explore current and future strategies to maximize the use of limited organs, to offer an update on potential new approaches to immunosuppression and to imagine new indications for LT when the number of patients awaiting transplants for HCV related liver disease is reduced.