Interpreting Outcomes in DCDD Liver Transplantation: First Report of the Multicenter IDOL Consortium

Donation After Circulatory Death Liver Transplantation: Early Challenges, Clinical Improvement, and Future Directions

Donation after circulatory death (DCD) liver allografts remain a widely underutilized source of donor organs for transplantation. Although initially linked with inferior outcomes, DCD liver transplant can achieve excellent patient and graft survival with suitable matching of donor and recipient characteristics, rapid donor recovery and precise donor assessment, and appropriate perioperative management. The advent of clinical liver perfusion modalities promises to redefine the viability parameters for DCD liver allografts and hopefully will encourage more widespread usage of this growing source of donor livers.

Older liver grafts from donation after circulatory death are associated with impaired survival and higher incidence of biliary non-anastomotic stricture

BACKGROUND

Grafts from older donors after circulatory death were associated with inferior outcome in liver transplants in the past. But it has seemed to remain controversial in the last decade, as a result of modified clinical protocols, selected recipients, and advanced technology of organ perfusion and preservation. The present study aimed to examine the impact of older donor age on complications and survival of liver transplant using grafts from donation after circulatory death (DCD).

METHODS

A total of 944 patients who received DCD liver transplantation from 2015 to 2020 were included and divided into two groups: using graft from older donor (aged ≥ 65 years, n = 87) and younger donor (age < 65 years, n = 857). Propensity score matching (PSM) was applied to eliminate selection bias.

RESULTS

A progressively increased proportion of liver transplants with grafts from older donors was observed from 1.68% to 15.44% during the study period. The well-balanced older donor (n = 79) and younger donor (n = 79) were 1:1 matched. There were significantly more episodes of biliary non-anastomotic stricture (NAS) in the older donor group than the younger donor group [15/79 (19.0%) vs. 6/79 (7.6%); P = 0.017]. The difference did not reach statistical significance regarding early allograft dysfunction (EAD) and primary non-function (PNF). Older livers had a trend toward inferior 1-, 2-, 3-year graft and overall survival compared with younger livers, but these differences were not statistically significant (63.1%, 57.6%, 57.6% vs. 76.9%, 70.2%, 67.7%, P = 0.112; 64.4%, 58.6%, 58.6% vs. 76.9%, 72.2%, 72.2%, P = 0.064). The only risk factor for poor survival was ABO incompatible transplant (P = 0.008) in the older donor group. In the subgroup of ABO incompatible cases, it demonstrated a significant difference in the rate of NAS between the older donor group and the younger donor group [6/8 (75.0%) vs. 3/14 (21.4%); P = 0.014].

CONCLUSIONS

Transplants with grafts from older donors (aged ≥ 65 years) after circulatory death are more frequently associated with inferior outcome compared to those from younger donors. Older grafts from DCD are more likely to develop NAS, especially in ABO incompatible cases.

Can ex-situ normothermic perfusion improve graft survival compared to static cold storage among donation after circulatory death liver allografts?

Limited data suggest that ex-situ normothermic liver perfusion (ENLP) may improve the outcomes of donation after circulatory death (DCD) liver transplants compared to static cold storage (SCS). All adult DCD liver transplants performed between 2016 and 2021 were identified in the United Network of Organ Sharing database. ENLP liver transplants were compared to SCS using inverse probability of treatment weighting to balance clinical and demographic confounders. The primary analysis simulated intention-to-treat with inverse probability of treatment weighting-adjusted Cox models. Compared to SCS DCDs (N = 3,079), recipients of ENLP DCDs (N = 65) had lower Model of End Stage Liver Disease scores at transplant (16.5 v. 18.8, p = 0.033), longer wait times (468 ± 720 vs. 246 ± 467 d; p < 0.001), and received livers from donors with a greater BMI (29.2 vs. 27.5; p = 0.008). ENLP preservation was associated with a lower risk of graft failure (HR 0.31 vs. SCS, 95% CI:0.12-0.86, p = 0.023) and a lower incidence of retransplantation. A sub-analysis restricted to the 20 centers performing ENLP, encompassing 946 SCS DCDs, demonstrated similar results: (HR 0.33 vs. SCS, 95% CI: 0.13-0.94, p = 0.021). Among 111 patients who required retransplantation and where the etiology of graft failure was identified, graft failure due to ischemic cholangiopathy was noted in 1 ENLP and 46 SCS. In this retrospective analysis of the early US DCD ENLP experience, there may exist a graft survival benefit to transplants performed with ENLP compared to SCS.

Ethical considerations for theatre teams in organ donation after circulatory determination of death

Transplant surgery is an area that gives rise to a number of ethical considerations. As medicine continues to expand the boundaries of what is technically possible, we must consider the ethical implications of our interventions, not solely on patients and society, but also on those asked to provide that care. Here, we consider physician participation in procedures required to provide patient care in the context of the ethical convictions held by the physician, with an emphasis on organ donation after circulatory determination of death. Strategies that can be used to mitigate any potential negative impact on the psychological well-being of members of the patient care team are considered.

Novel Benchmark Values for Redo Liver Transplantation: Does the Outcome Justify the Effort?

OBJECTIVE

To define benchmark cutoffs for redo liver transplantation (redo-LT).

BACKGROUND

In the era of organ shortage, redo-LT is frequently discussed in terms of expected poor outcome and wasteful resources. However, there is a lack of benchmark data to reliably evaluate outcomes after redo-LT.

METHODS

We collected data on redo-LT between January 2010 and December 2018 from 22 high-volume transplant centers. Benchmark cases were defined as recipients with model of end stage liver disease (MELD) score ≤25, absence of portal vein thrombosis, no mechanical ventilation at the time of surgery, receiving a graft from a donor after brain death. Also, high-urgent priority and early redo-LT including those for primary nonfunction (PNF) or hepatic artery thrombosis were excluded. Benchmark cutoffs were derived from the 75th percentile of the medians of all benchmark centers.

RESULTS

Of 1110 redo-LT, 373 (34%) cases qualified as benchmark cases. Among these cases, the rate of postoperative complications until discharge was 76%, and increased up to 87% at 1-year, respectively. One-year overall survival rate was excellent with 90%. Benchmark cutoffs included Comprehensive Complication Index CCI ® at 1-year of ≤72, and in-hospital and 1-year mortality rates of ≤13% and ≤15%, respectively. In contrast, patients who received a redo-LT for PNF showed worse outcomes with some values dramatically outside the redo-LT benchmarks.

CONCLUSION

This study shows that redo-LT achieves good outcome when looking at benchmark scenarios. However, this figure changes in high-risk redo-LT, as for example in PNF. This analysis objectifies for the first-time results and efforts for redo-LT and can serve as a basis for discussion about the use of scarce resources.

Lost potential and missed opportunities for DCD liver transplantation in the United States

BACKGROUND

Donation after cardiac death(DCD) has been proposed as an avenue to expand the liver donor pool.

METHODS

We examined factors associated with nonrecovery of DCD livers using UNOS data from 2015 to 2019.

RESULTS

There 265 non-recovered potential(NRP) DCD livers. Blood type AB (7.8% vs. 1.1%) and B (16.9% vs. 9.8%) were more frequent in the NRP versus actual donors (p < 0.001). The median driving time between donor hospital and transplant center was similar for NRP and actual donors (30.1 min vs. 30.0 min; p = 0.689), as was the percentage located within a transplant hospital (20.8% vs. 20.9%; p = 0.984).The donation service area(DSA) of a donor hospital explained 27.9% (p = 0.001) of the variability in whether a DCD liver was recovered.

CONCLUSION

A number of potentially high quality DCD donor livers go unrecovered each year, which may be partially explained by donor blood type and variation in regional and DSA level practice patterns.

Liver Transplantation in Sexagenarian Patients Using Grafts From Uncontrolled Circulatory Death Versus Grafts From Brain Death Donation

BACKGROUND

An increased number of older recipients underwent liver transplantation in recent years, and consequently needing to obtain more liver grafts. In order to increase this pool, in 2006, we initiated the use of livers from uncontrolled circulatory death (uDCD). We analyzed the use of uDCD livers in sexagenarian recipients and their effect on overall survival.

METHODS

A retrospective and comparative study was performed among 4 groups according to recipient age (less or greater than 60 years) and donor type (donor brain death [DBD] or uDCD): Group A: DBD livers in recipients aged <60 years (n = 169); Group B: uDCD livers in recipients aged <60 years (n = 36); Group C: DBD livers in recipients aged >60 years (n = 96); and Group D: uDCD livers in recipients aged >60 years(n = 39).

RESULTS

Intraoperative transfusion, biliary complications, primary non-function, acute rejection, chronic renal dysfunction, retransplantation, and mortality during follow-up (cardiovascular diseases in 3 patients, hepatitis C virus recurrence in 4 patients, and de novo malignancies in 3 patients) were significantly higher, and 5-year patient and graft survival was significantly lower in sexagenarian recipients. Bilirubin and packed red blood cells transfusion were risk factors for patient survival, whereas hepatocelular carcinoma, creatinine, and packed red blood cells transfusion were risk factors for patient survival. Recipient age (<60 years) was confirmed as protective factor for patient and graft survival, whereas the use of uDCD was not a risk factor for patient or graft survival.

CONCLUSIONS

Use of a uDCD liver did not demonstrate as a risk factor for patient and graft survival, and recipient age (<60 years) was a protective factor for patient and graft survival.

Classification of Distinct Patterns of Ischemic Cholangiopathy Following DCD Liver Transplantation: Distinct Clinical Courses and Long-term Outcomes From a Multicenter Cohort

BACKGROUND

As the number of donation after circulatory death (DCD) liver transplants (LTs) performed in the United States continues to increase annually, there has been interest by policy makers to develop a more robust exception point safety net for patients who develop ischemic cholangiopathy (IC) following DCD LT. As such, there is a need for better understanding of the clinical course and long-term outcomes in patients who develop IC, as well as determining if IC can be classified into distinct categories with distinctly different clinical outcomes.

METHODS

All DCD LT performed at Mayo Clinic Florida, Mayo Clinic Arizona, and Mayo Clinic Rochester from January 1999 to March 2020 were included (N = 770). Outcomes were compared between 4 distinct radiologic patterns of IC: diffuse necrosis, multifocal progressive, confluence dominant, and minor form.

RESULTS

In total, 88 (11.4%) patients developed IC, of which 42 (5.5%) were listed for retransplantation of liver (ReLT). Patients with diffuse necrosis and multifocal progressive patterns suffered from frequent hospital admissions for cholangitis in the first year following DCD LT (median 3 and 2), were largely stent dependent (100% and 85.7%), and almost universally required ReLT. Patients with confluence dominant disease were managed with multiple stents and frequently recovered, ultimately becoming stent free without need for ReLT. Patients with the minor form IC did well with limited need for stent placement or repeat procedures and did not require ReLT. Graft survival was different between the 4 distinct IC patterns (P < 0.001).

CONCLUSIONS

The present analysis provides a detailed analysis on the natural history and clinical course of IC. Patients developing IC can be classified into 4 distinct patterns with distinct clinical courses.

Recommendations for Donor and Recipient Selection and Risk Prediction: Working Group Report From the ILTS Consensus Conference in DCD Liver Transplantation

Although the utilization of donation after circulatory death donors (DCDs) for liver transplantation (LT) has increased steadily, much controversy remains, and no common acceptance criteria exist with regard to donor and recipient risk factors and prediction models. A consensus conference was organized by International Liver Transplantation Society on January 31, 2020, in Venice, Italy, to review the current clinical practice worldwide regarding DCD-LT and to develop internationally accepted guidelines. The format of the conference was based on the grade system. International experts in this field were allocated to 6 working groups and prepared evidence-based recommendations to answer-specific questions considering the currently available literature. Working group members and conference attendees served as jury to edit and confirm the final recommendations presented at the end of the conference by each working group separately. This report presents the final statements and recommendations provided by working group 2, covering the entire spectrum of donor and recipient risk factors and prediction models in DCD-LT.

Early Allograft Dysfunction and Complications in DCD Liver Transplantation: Expert Consensus Statements From the International Liver Transplantation Society

Livers for transplantation from donation after circulatory death donors are relatively more prone to early and ongoing alterations in graft function that might ultimately lead to graft loss and even patient death. In consideration of this fact, this working group of the International Liver Transplantation Society has performed a critical evaluation of the medical literature to create a set of statements regarding the assessment of early allograft function/dysfunction and complications arising in the setting of donation after circulatory death liver transplantation.

Cholangiocyte Epithelial to Mesenchymal Transition (EMT) is a potential molecular mechanism driving ischemic cholangiopathy in liver transplantation

Donation after circulatory death (DCD) has expanded the donor pool for liver transplantation. However, ischemic cholangiopathy (IC) after DCD liver transplantation causes inferior outcomes. The molecular mechanisms of IC are currently unknown but may depend on ischemia-induced genetic reprograming of the biliary epithelium to mesenchymal-like cells. The main objective of this study was to determine if cholangiocytes undergo epithelial to mesenchymal transition (EMT) after exposure to DCD conditions and if this causally contributes to the phenotype of IC. Human cholangiocyte cultures were exposed to periods of warm and cold ischemia to mimic DCD liver donation. EMT was tested by assays of cell migration, cell morphology, and differential gene expression. Transplantation of syngeneic rat livers recovered under DCD conditions were evaluated for EMT changes by immunohistochemistry. Human cholangiocytes exposed to DCD conditions displayed migratory behavior and gene expression patterns consistent with EMT. E-cadherin and CK-7 expressions fell while N-cadherin, vimentin, TGFβ, and SNAIL rose, starting 24 hours and peaking 1-3 weeks after exposure. Cholangiocyte morphology changed from cuboidal (epithelial) before to spindle shaped (mesenchymal) a week after ischemia. These changes were blocked by pretreating cells with the Transforming Growth Factor beta (TGFβ) receptor antagonist Galunisertib (1 μM). Finally, rats with liver isografts cold stored for 20 hours in UW solution and exposed to warm ischemia (30 minutes) at recovery had elevated plasma bilirubin 1 week after transplantation and the liver tissue showed immunohistochemical evidence of early cholangiocyte EMT. Our findings show EMT occurs after exposure of human cholangiocytes to DCD conditions, which may be initiated by upstream signaling from autocrine derived TGFβ to cause mesenchymal specific morphological and migratory changes.

Liver transplantation for hepatocellular carcinoma using grafts from uncontrolled circulatory death donation

Controversy exists regarding whether the rate of hepatocellular carcinoma (HCC) recurrence after orthotopic liver transplantation (OLT) differs when using livers from donation after controlled circulatory death (DCD) versus livers from donation after brain death (DBD). The aim of this cohort study was to analyze rates of HCC recurrence, patient survival, and graft survival after OLT for HCC, comparing recipients of DBD livers (n = 103) with recipients of uncontrolled DCD livers (uDCD; n = 41). No significant differences in tumor size, tumor number, serum alpha-fetoprotein, proportion of patients within Milan criteria, or pre-OLT bridging therapies were identified between groups, although the waitlist period was significantly shorter in the uDCD group (p = 0.040). HCC recurrence was similar between groups. Patient survival was similar between groups, but graft survival was lower in the uDCD group. Multivariate analysis identified recipient age (p = 0.031), pre-OLT bridging therapy (p = 0.024), and HCC recurrence (p = 0.048) as independent risk factors for patient survival and pre-OLT transarterial chemoembolization (p = 0.045) as the single risk factor for HCC recurrence. In conclusion, similar patient survival and lower graft survival were observed in the uDCD group. However, the use of uDCD livers appears to be justified due to a shorter waitlist time, and lower waitlist dropout and HCC recurrence rates.

Incidence and risk factors of primary non-function after liver transplantation using grafts from uncontrolled donors after circulatory death

BACKGROUND

Graft primary non-function (PNF) is the most severe complication after orthotopic liver transplantation (OLT) and is frequently associated with livers from uncontrolled circulatory death (uDCD).

METHODS

We reviewed retrospectively the incidence, risk factors, and outcome of patients showing PNF after receiving uDCD liver grafts. The series comprises 75 OLT performed during 11 years.

RESULTS

The incidence of PNF using uDCD livers was 8%. We compared patients who developed PNF (n = 6) vs. patients without PNF (n = 69). Mean pump flow of donors during normothermic regional perfusion (NRP) was significantly lower in PNF (p = .032). Day 1 post-OLT levels of transaminases and the incidence of renal complications and postoperative mortality were also significantly higher in the PNF group, but 5-year patient survival was similar in both groups (66.7% in PNF and 68.5% in non-PNF). All PNF patients underwent re-OLT, and 2 died. PNF incidence has decreased in the last 5-years. Binary logistic regression analysis confirmed final ALT value >4 times the normal value as risk factor for PNF, and median donor pump flow >3700 ml/min as protective effect.

CONCLUSIONS

Adequate donor pump flow during NRP was a protective.

Donation After Circulatory Death Is Associated With Similar Posttransplant Survival in All but the Highest-Risk Hepatocellular Carcinoma Patients

Liver transplantation (LT) recipients with hepatocellular carcinoma (HCC) receive a higher proportion of livers from donation after circulatory death (DCD) donors compared with non-HCC etiologies. Nevertheless, data on outcomes in patients with HCC receiving DCD grafts are limited. We evaluated the influence of DCD livers on post-LT outcome among HCC patients. We identified 7563 patients in the United Network for Organ Sharing (UNOS) database who underwent LT with Model for End-Stage Liver Disease score exceptions from 2012 to 2016, including 567 (7.5%) who received a DCD donor organ and 6996 (92.5%) who received a donation after brain death (DBD) donor organ. Kaplan-Meier probabilities of post-LT HCC recurrence at 3 years were 7.6% for DCD and 6.4% for DBD recipients (P = 0.67) and post-LT survival at 3 years was 81.1% versus 85.5%, respectively (P = 0.008). On multivariate analysis, DCD donor (hazard ratio, 1.38; P = 0.005) was an independent predictor of post-LT mortality. However, a survival difference after LT was only observed in subgroups at higher risk for HCC recurrence including Risk Estimation of Tumor Recurrence After Transplant (RETREAT) score ≥4 (DCD 57.0% versus DBD 72.6%; P = 0.02), alpha-fetoprotein (AFP) ≥100 (60.1% versus 76.9%; P = 0.049), and multiple viable tumors on last imaging before LT (69.9% versus 83.1%; P = 0.002). In this analysis of HCC patients receiving DCD versus DBD livers in the UNOS database, we found that patients with a low-to-moderate risk of HCC recurrence (80%-90% of the DCD cohort) had equivalent survival regardless of donor type. It appears that DCD donation can best be used to increase the donor pool for HCC patients with decompensated cirrhosis or partial response/stable disease after locoregional therapy with AFP at LT <100 ng/mL.

Donation after Circulatory Death: Potential Mechanisms of Injury and Preventative Strategies

Donation after circulatory death (DCD) donors represent a potential means to help address the disparity between the number of patients awaiting liver transplantation (LT) and the availability of donor livers. While initial enthusiasm for DCD LT was high in the early 2000s, early reports of high rates of biliary complications and inferior graft survival resulted in reluctance among many transplant centers to use DCD liver grafts. As with all innovations in transplant practice, there is undoubtedly a learning curve associated with the optimal utilization of liver grafts from DCD donors. More contemporary data has demonstrated that results with DCD LT are improving and the number of DCD LT performed annually has been steadily increasing. In this concise review, potential mechanisms of injury for DCD livers are discussed along with strategies that have been employed in clinical practice to improve DCD LT outcomes.

Liver Transplantation Using Uncontrolled Donors After Circulatory Death: A 10-year Single-center Experience

BACKGROUND

One method for increasing the donor pool for orthotopic liver transplantations (OLTs) is to use uncontrolled donation after circulation death (uDCDs).

METHODS

From January 2006 to December 2016, we performed 75 OLTs using uDCD livers. The control group comprised a sample of 265 OLTs using livers of donations after brain death (DBDs). A comparative study was performed.

RESULTS

Of 256 potential uDCD donors cannulated, 75 (29.3%) livers were accepted for OLT. The amount of hemoderivatives transfused was significantly higher in the uDCD group. The rate of primary nonfunction was also significantly higher (P = 0.031) in uDCD recipients (8%) than DBD recipients (1.5%). The overall rate of biliary complications was significantly higher (P = 0.001) in uDCD recipients (23 cases, 30.6%) than DBD recipients (28 cases, 10.6%). In the uDCD group, 1-, 3-, and 5-year patient survival rates were 82.7%, 73%, and 71.5%, respectively; in the DBD group, they were 89%, 83.7%, and 78.8%, respectively (P = 0.180). In the uDCD group, 1-, 3-, and 5-year graft survival rates were 73.3%, 65.1%, and 63.6%, respectively; in the DBD group, they were 87.1%, 81.9%, and 76.5%, respectively (P = 0.013). Multivariate analysis showed that independent risk factors for patient and graft survival were intraoperative transfusion of >6 units of packed red blood cell concentrates and recipients who were older than 60 years.

CONCLUSIONS

Although graft survival is significantly lower using uDCD livers, 5-year patient survival in recipients of DBD and uDCD livers is similar. After careful selection, the livers of uDCD can be selectively used for OLT.

Biliary Complications After Liver Transplantation From Uncontrolled Donors After Circulatory Death: Incidence, Management, and Outcome

The utilization of livers from donation after uncontrolled circulatory death (uDCD) increases the availability of liver grafts, but it is associated with a higher incidence of biliary complications (BCs) and lower graft survival than those organs donated after brain death. From January 2006 to December 2016, we performed 75 orthotopic liver transplantations (OLTs) using uDCD livers. To investigate the relationship of BCs with the use of uDCD OLT, we compared patients who developed BCs (23 patients) with those who did not (non-BC group, 43 patients) after excluding cases of hepatic artery thrombosis (a known cause of BC) and primary nonfunction. The groups had similar uDCD donor maintenance, donor and recipient characteristics, and perioperative morbidity/mortality rates, but we observed a higher rate of hepatocellular carcinoma and hepatitis C virus in the non-BC group. Percutaneous transhepatic biliary dilation, endoscopic retrograde cholangiopancreatography dilation, Roux-en-Y hepaticojejunostomy (HJ), a T-tube, and retransplantation were used for BC management. In the BC group, 1-, 3-, and 5-year patient survival rates were 91.3%, 69.6%, and 65.2%, respectively, versus 77.8%, 72.9%, and 72.9%, respectively, in the non-BC group (P = 0.89). However, 1-, 3-, and 5-year graft survival rates were 78.3%, 60.9%, and 56.5%, respectively, in the BC group versus 77.8%, 72.9%, and 72.9%, respectively, in the non-BC group (P = 0.38). Multivariate analysis did not indicate independent risk factors for BC development. In conclusion, patient and graft survival rates were generally lower in patients who developed BCs but not significantly so. These complications were managed in the majority of patients through radiological dilation, endoscopic dilation, or Roux-en-Y HJ. Retransplantation is necessary in rare cases after the failure of biliary dilation or surgical procedures.

Machine perfusion strategies in liver transplantation

Machine perfusion is a hot topic in liver transplantation and several new perfusion concepts are currently developed. Prior to introduction into routine clinical practice, however, such perfusion approaches need to demonstrate their impact on liver function, post-transplant complications, utilization rates of high-risk organs, and cost benefits. Therefore, based on results of experimental and clinical studies, the community has to recognize the limitations of this technology. In this review, we summarize current perfusion concepts and differences between protective mechanisms of ex- and in-situ perfusion techniques. Next, we discuss which graft types may benefit most from perfusion techniques, and highlight the current understanding of liver viability testing. Finally, we present results from recent clinical trials involving machine liver perfusion, and analyze the value of different outcome parameters, currently used as endpoints for randomized controlled trials in the field.

Can hypothermic oxygenated perfusion (HOPE) rescue futile DCD liver grafts?

BACKGROUND

The new UK-DCD-Risk-Score has been recently developed to predict graft loss in DCD liver transplantation. Donor-recipient combinations with a cumulative risk of >10 points were classified as futile and achieved an impaired one-year graft survival of <40%. The aim of this study was to show, if hypothermic oxygenated perfusion (HOPE) can rescue such extended DCD livers and improve outcomes.

METHODS

"Futile"-classified donor-recipient combinations were selected from our HOPE-treated human DCD liver cohort (01/2012-5/2017), with a minimum follow-up of one year. Main risk factors, which contribute to the classification "futile" include: elderly donors>60years, prolonged functional donor warm ischemia time (fDWIT > 30min), long cold ischemia time>6hrs, donor BMI>25 kg/m², advanced recipient age (>60years), MELD-score>25points and retransplantation status. Endpoints included all outcome measures during and after DCD LT.

RESULTS

Twenty-one donor-recipient combinations were classified futile (median UK-DCD-Risk-Score:11 points). The median donor age and fDWIT were 62 years and 36 min, respectively. After cold storage, livers underwent routine HOPE-treatment for 120 min. All grafts showed immediate function. One-year and 5-year tumor death censored graft survival was 86%.

CONCLUSION

HOPE-treatment achieved excellent outcomes, despite high-risk donor and recipient combinations. Such easy, endischemic perfusion approach may open the door for an increased utilization of futile DCD livers in other countries.

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.

The UK-DCD-Risk-Score - practical and new guidance for allocation of a specific organ to a recipient?

Introduction: Multiple factors contribute to the overall outcome in donation after circulatory death liver transplantation. The majority is however inconsistently reported with various acceptance criteria and thresholds, when to decline a specific graft. Recent improvement in outcome was based on an increased awareness of the cumulative risk, combining donor and recipient parameters, which encouraged the community to accept livers with an overall higher risk. Areas covered: This review pictures the large number of risk factors in this field with a special focus on parameters, which contribute to available prediction models. Next, features of the recently developed UK-DCD-Risk-Score, which led to a significantly impaired graft survival, above a suggested threshold of >10 score points, are discussed. The clinical impact of this new model on the background of other prediction tools with their subsequent limitations is highlighted in a next chapter. Finally, we provide suggestions, how to further improve outcomes in this challenging field of transplantation. Expert opinion: Despite the recent development of new prediction models, including the UK-DCD-Risk-Score, which provides a sufficient prediction of graft loss after DCD liver transplantation, the consideration of other confounders is essential to better understand the overall risk and metabolic liver status to improve the comparability of clinical studies. More uniform definitions and thresholds of individual risk factors are required.

Retrieval Practice or Overall Donor and Recipient Risk: What Impacts on Outcomes After Donation After Circulatory Death Liver Transplantation in the United Kingdom?

Parameters of retrieval surgery are meticulously documented in the United Kingdom, where up to 40% of livers are donation after circulatory death (DCD) donations. This retrospective analysis focuses on outcomes after transplantation of DCD livers, retrieved by different UK centers between 2011 and 2016. Donor and recipient risk factors and the donor retrieval technique were assessed. A total of 236 DCD livers from 9 retrieval centers with a median UK DCD risk score of 5 (low risk) to 7 points (high risk) were compared. The majority used University of Wisconsin solution for aortic flush with a median hepatectomy time of 27-44 minutes. The overall liver injury rate appeared relatively high (27.1%) with an observed tendency toward more retrieval injuries from centers performing a quicker hepatectomy. Among all included risk factors, the UK DCD risk score remained the best predictor for overall graft loss in the multivariate analysis (P < 0.001). In high-risk and futile donor-recipient combinations, the occurrence of liver retrieval injuries had negative impact on graft survival (P = 0.023). Expectedly, more ischemic cholangiopathies (P = 0.003) were found in livers transplanted with a higher cumulative donor-recipient risk. Although more biliary complications with subsequent graft loss were found in high-risk donor-recipient combinations, the impact of the standardized national retrieval practice on outcomes after DCD liver transplantation was minimal.

Donation after circulatory death and its expansion in Spain

PURPOSE OF REVIEW

Donation after circulatory death (DCD) is still performed in a limited number of countries. This article summarizes the development of DCD in Spain and presents recent Spanish contributions to gain knowledge on the potential benefits and the practical use of normothermic regional perfusion (nRP).

RECENT FINDINGS

DCD now contributes to 24% of deceased donors in Spain. The development of DCD has been based on an assessment of practices in the treatment of cardiac arrest and end-of-life care to accommodate the option of DCD; the creation of an adequate regulatory framework; and institutional support, professional training and public education. Appropriate posttransplant outcomes have been obtained with organs from both uncontrolled and controlled DCD donors. nRP is increasingly used, with preliminary data supporting improved results compared with other in-situ preservation/recovery approaches. Mobile teams with portable extracorporeal membrane oxygenation devices are making nRP possible in hospitals without these resources. To avoid the possibility of reestablishing brain circulation after the determination of death, a specific methodology has been validated.

SUMMARY

DCD has been successfully developed in Spain following a streamlined process. nRP may become a standard in DCD, although further evidence on the benefits of this technology is eagerly awaited.

Vascular and Biliary Complications Following Deceased Donor Liver Transplantation: A Meta-analysis

OBJECTIVE

To assess biliary and vascular complications after liver transplantations (LTs) sourced from deceased donors.

METHODS

This study reviewed potentially relevant English-language articles gathered from PubMed and Medline published from 2012 to 2017. One additional study was carried out using our institution's database for articles published from 2013 to 2017. Biliary and vascular complications from adult patients receiving their first deceased-donor LT were included. This meta-analysis was performed using Review Manager version 5.2 (Cochrane Collaboration, Copenhagen, Denmark) and the study quality was evaluated using the Newcastle-Ottawa Scale.

RESULTS

Ten studies met our inclusion criteria. Heterogeneity in donation after cardiac death (DCD) and donation after brain death (DBD) recipients was observed and minimized after pooling a subgroup analysis. This latter analysis focused on biliary stricture, biliary leaks and stones, and vascular thrombosis and stenosis. Meta-analyses showed that patients receiving DCD organs have a greatly increased risk of biliary complications compared to those receiving DBD organs, particularly the following: biliary leaks and stones (odds ratio [OR] = 1.69, 95% confidence interval [CI] 1.22-2.34); and biliary stricture (OR = 1.58, 95% CI 1.21-2.06). DCD grafts tended to be but were not significantly associated with DBD regarding vascular thrombosis (OR = 1.62, 95% CI 1.05-2.50), and the risk of vascular stenosis in DCD grafts was not statistically significant (OR = 1.25, 95% CI, .70-2.25).

CONCLUSION

DCD was associated with an increased risk of biliary complications after LT, tended to indicate an increased risk of vascular thrombosis versus, and was not associated with an increased risk of vascular stenosis compared to DBD. There was no significant difference between the grafts.

Impact of Machine Perfusion on Biliary Complications after Liver Transplantation

We describe in this review the different types of injuries caused to the biliary tree after liver transplantation. Furthermore, we explain underlying mechanisms and why oxygenated perfusion concepts could not only protect livers, but also repair high-risk grafts to prevent severe biliary complications and graft loss. Accordingly, we summarize experimental studies and clinical applications of machine liver perfusion with a focus on biliary complications after liver transplantation. Key points: (1) Acute inflammation with subsequent chronic ongoing liver inflammation and injury are the main triggers for cholangiocyte injury and biliary tree transformation, including non-anastomotic strictures; (2) Hypothermic oxygenated perfusion (HOPE) protects livers from initial oxidative injury at normothermic reperfusion after liver transplantation. This is a unique feature of a cold oxygenation approach, which is effective also end-ischemically, e.g., after cold storage, due to mitochondrial repair mechanisms. In contrast, normothermic oxygenated perfusion concepts protect by reducing cold ischemia, and are therefore most beneficial when applied instead of cold storage; (3) Due to less downstream activation of cholangiocytes, hypothermic oxygenated perfusion also significantly reduces the development of biliary strictures after liver transplantation.

Donation after Circulatory Death in Paediatric Liver Transplantation: Current Status and Future Perspectives in the Machine Perfusion Era

Efforts have been made by the transplant community to expand the deceased donor pool in paediatric liver transplantation (LT). The growing experience on donation after circulatory death (DCD) for adult LT has encouraged its use also in children, albeit in selective cases, opening new perspectives for paediatric patients. Even though there has recently been a slight increase in the number of DCD livers transplanted in children, with satisfactory graft and patient outcomes, the use of DCD grafts in paediatric recipients is still controversial due to morbid outcomes associated with DCD grafts. In this context, recent advances in the optimization of donor support by extracorporeal membrane oxygenation and in the graft preservation by liver machine perfusion could find application in order to expand the donor pool in paediatric LT. In the present study we review the current literature on DCD liver grafts transplanted in children and on the use of extracorporeal donor support and liver perfusion machines in paediatrics, with the aim of defining the current status and future perspectives of paediatric LT.

Impact of donor age in donation after circulatory death liver transplantation: Is the cutoff "60" still of relevance?

Advanced donor age has been identified as a risk factor when combined with donor warm ischemia time (WIT), eg, in donation after circulatory death (DCD). In several countries, DCD livers older than 60 years are not considered suitable due to concerns related to poor graft function and development of ischemic cholangiopathy. In this study, we evaluate outcomes after DCD liver transplantation using grafts from donors older than 60 years. We analyzed outcomes after DCD liver transplantation (n = 315), comparing donors > 60 years (n = 93) and donors ≤ 60 years (n = 222) from our center between 2005 and 2015. End points included graft function and complications and patient and graft survival. Multivariate risk analysis was performed to define further key factors that predicted inferior outcome. Donor age at the cutoff 60 years failed to stratify patient and graft survival. The rate of vascular, biliary, and overall complications was comparably low in both cohorts, and the median comprehensive complication index was 42.7 points, independent from the donor age. Second, donor body mass index (BMI) above a threshold of 25 kg/m² significantly impacted on graft and patient survival at any donor age, whereas donor WIT and cold ischemia times were not predictive for graft loss. In conclusion, older DCD donors can be successfully used for liver transplantation with good longterm outcomes when further risk factors are limited. Additional risk is transmitted by an increased donor BMI regardless of donor age. Liver Transplantation 24 352-362 2018 AASLD.