Expanding the Donor Pool With the Use of Extended Criteria Donation After Circulatory Death Livers

Better liver transplant outcomes by donor interventions?

PURPOSE OF REVIEW

Donor risk factors and events surrounding donation impact the quantity and quality of grafts generated to meet liver transplant waitlist demands. Donor interventions represent an opportunity to mitigate injury and risk factors within donors themselves. The purpose of this review is to describe issues to address among donation after brain death, donation after circulatory determination of death, and living donors directly, for the sake of optimizing relevant outcomes among donors and recipients.

RECENT FINDINGS

Studies on donor management practices and high-level evidence supporting specific interventions are scarce. Nonetheless, for donation after brain death (DBD), critical care principles are employed to correct cardiocirculatory compromise, impaired tissue oxygenation and perfusion, and neurohormonal deficits. As well, certain treatments as well as marginally prolonging duration of brain death among otherwise stable donors may help improve posttransplant outcomes. In donation after circulatory determination of death (DCD), interventions are performed to limit warm ischemia and reverse its adverse effects. Finally, dietary and exercise programs have improved donation outcomes for both standard as well as overweight living donor (LD) candidates, while minimally invasive surgical techniques may offer improved outcomes among LD themselves.

SUMMARY

Donor interventions represent means to improve liver transplant yield and outcomes of liver donors and grafts.

Inter-patient heterogeneity in the hepatic ischemia-reperfusion injury transcriptome: Implications for research and diagnostics

Cellular responses induced by surgical procedure or ischemia-reperfusion injury (IRI) may severely alter transcriptome profiles and complicate molecular diagnostics. To investigate this effect, we characterized such pre-analytical effects in 143 non-malignant liver samples obtained from 30 patients at different time points of ischemia during surgery from two individual cohorts treated either with the Pringle manoeuvre or total vascular exclusion. Transcriptomics profiles were analyzed by Affymetrix microarrays and expression of selected mRNAs was validated by RT-PCR. We found 179 mutually deregulated genes which point to elevated cytokine signaling with NFκB as a dominant pathway in ischemia responses. In contrast to ischemia, reperfusion induced pro-apoptotic and pro-inflammatory cascades involving TNF, NFκB and MAPK pathways. FOS and JUN were down-regulated in steatosis compared to their up-regulation in normal livers. Surprisingly, molecular signatures of underlying primary and secondary cancers were present in non-tumor tissue. The reported inter-patient variability might reflect differences in individual stress responses and impact of underlying disease conditions. Furthermore, we provide a set of 230 pre-analytically highly robust genes identified from histologically normal livers (<2% covariation across both cohorts) that might serve as reference genes and could be particularly suited for future diagnostic applications.

Liver machine perfusion technology: Expanding the donor pool to improve access to liver transplantation

The imbalance between organ supply and demand continues to limit the broader benefits of organ transplantation. Machine perfusion (MP) may increase the supply of donor livers by expanding the use of extended-criteria donors. Using the United Network for Organ Sharing/Organ Procurement and Transplantation Network and the Standard Transplant Analysis and Research dataset, we reviewed the effect of MP implementation on the behavior of transplant centers. We identified 15 high-utilizing MP centers that were matched to suitable controls based on volume and geographical proximity. We conducted a differences-in-differences analysis using linear regression to estimate the impact of MP adoption on the transplant centers' donor utilization. We found a significant increase in cold ischemia time and organs with donor warm ischemia time over 30 minutes (P < .05). After removing one outlier center, the analysis showed that these centers through MP accepted overall more donation after circulatory death donors, donation after circulatory death donors over 50 years old, donors with macrovesicular steatosis greater than 30% on liver biopsy, and donor warm ischemia time over 30 minutes (P < .05). MP has allowed centers to expand their use of extended-criteria donors beyond traditional cutoffs and to increase patient access to liver transplantation.

Using extracorporeal membrane oxygenation in donations after cardiac death or brain death: A single-center experience and long-term outcome

Aims

The use of extended criteria donors is a routine practice that sometimes involves extracorporeal membrane oxygenation (ECMO) in donations after cardiac death or brain death.

Methods

We performed a retrospective study in a single center from January 2006 to December 2019. The study included 90 deceased donor liver transplants. The patients were divided into three groups: the donation after brain death (DBD) group (n = 58, 64.4%), the DBD with ECMO group (n = 11, 12.2%) and the donation after cardiac death (DCD) with ECMO group (n = 21, 23.3%).

Results

There were no significant differences between the DBD with ECMO group and the DBD group. When comparing the DCD with ECMO group and the DBD group, there were statistically significant differences for total warm ischemia time (p < 0.001), total cold ischemia time (p = 0.023), and split liver transplantation (p < 0.001), and there was significantly poor recovery in regard to total bilirubin level (p = 0.027) for the DCD with ECMO group by repeated measures ANOVA. The 5-year survival rates of the DBD, DBD with ECMO, and DCD with ECMO groups were 78.1%, 90.9%, and 75.6%, respectively. The survival rate was not significantly different when comparing the DBD group to either the DBD with ECMO group (p = 0.435) or the DCD with ECMO group (p = 0.310).

Conclusions

Using ECMO in donations after cardiac death or brain death is a good technology, and it contributed to 35.6% of the liver graft pool.

Insights into the history and tendency of liver transplantation for liver cancer: a bibliometric-based visual analysis

Research on liver transplantation (LT) for liver cancer has gained increasing attention. This paper has comprehensively described the current status, hotspots and trends in this field. A total of 2991 relevant articles from 1 January 1963 to 28 February 2023 were obtained from the Web of Science Core Collection. VOSviewer and CiteSpace software were utilized as bibliometric tools to analyze and visualize knowledge mapping. Between 1963 and 2023, the number of papers in the area of LT for liver cancer increased continuously. A total of 70 countries/regions, 2303 institutions and 14 840 researchers have published research articles, with the United States and China being the two most productive countries. Our bibliometric-based visual analysis revealed the expansion of LT indications for liver cancer and the prevention/treatment of cancer recurrence as ongoing research hotspots over the past decades. Meanwhile, emerging studies also focus on downstaging/bridging treatments before LT and the long-term survival of LT recipient, in particular the precise application of immunosuppressants.

Post-transplant outcomes and financial burden of donation after circulatory death donor liver transplant after the implementation of acuity circle policy

BACKGROUND

After implementation of the Acuity Circles (AC) allocation policy, use of DCD liver grafts has increased in the United States.

METHODS

We evaluated the impact of AC on rates of DCD-liver transplants (LT), their outcomes, and medical costs in a single practice. Adult LT patients were classified into three eras: Era 1 (pre-AC, 1/01/2015-12/31/2017); Era 2 (late pre-AC era, 1/01/2018-02/03/2020); and Era 3 (AC era, 05/10/2020-09/30/2021).

RESULTS

A total of 520 eligible LTs were performed; 87 were DCD, and 433 were DBD. With each successive era, the proportion of DCD increased (Era 1: 11%; Era 2: 20%; Era 3: 24%; p < .001). DCD recipients had longer ICU stays, higher re-admission/re-operation rates, and higher incidence of ischemic cholangiopathy compared to those with DBD. Direct, surgical, and ICU costs during first admission were higher with DCD than DBD (+8.0%, p < .001; +4.2%, p < .001; and +33.3%, p = .001). DCD-related costs increased after Era 1 (Direct: +4.9% [Era 2 vs. 1] and +12.4% [Era 3 vs. 1], p = .04; Surgical: +17.7% and +21.7%, p < .001). In the AC era, there was a significantly higher proportion of donors ≥50 years, and more national organ sharing. Compared to DCD from donors <50 years, DCD from donors ≥50 years was associated with significantly higher total direct, surgical, and ICU costs (+12.6%, p = .01; +9.5%, p = .01; +84.6%, p = .03).

CONCLUSIONS

The proportion of DCD-LT, especially from older donors, has increased after the implementation of AC policies. These changes are likely to be associated with higher costs in the AC era.

British Transplantation Society guidelines on abdominal organ transplantation from deceased donors after circulatory death

The British Transplantation Society (BTS) 'Guideline on transplantation from deceased donors after circulatory death' has recently been updated and this manuscript summarises the relevant recommendations in abdominal organ transplantation from Donation after Circulatory Death (DCD) donors, encompassing the chapters on liver, kidney, pancreas and islet cell transplantation.

Outcomes Of Lung And Liver Transplantation After Simultaneous Recovery Using Abdominal Normothermic Regional Perfusion In Donors After The Circulatory Determination Of Death Versus Donors After Brain Death

Normothermic regional perfusion (NRP) in controlled donation after the circulatory determination of death (cDCD) is a growing preservation technique for abdominal organs that coexists with the rapid recovery of lungs. We aim at describing the outcomes of lung transplants (LuTx) and liver transplants (LiTx) when both grafts are simultaneously recovered from cDCD donors using NRP, and compare them to donation after brain death (DBD). All LuTx and LiTx meeting these criteria during January-2015 to December-2020 in Spain were included in the study. Simultaneous recovery of lungs and livers was undertaken in 227 (17%) cDCD with NRP and 1,879 (21%) DBD donors (p<0.001). Primary graft dysfunction grade-3 within the first 72hours was similar in both LuTx groups (14.7% cDCD vs. 10.5% DBD;p=0.139). LuTx survival at 1 and 3years was 79.9% and 66.4% in cDCD, vs. 81.9% and 69.7% in DBD (p=0.403). The incidence of primary non-function and ischemic cholangiopathy was similar in both LiTx groups. Graft survival at 1 and 3years was 89.7% and 80.8% in cDCD vs. 88.2% and 82.1% in DBD LiTx (p=0.669). In conclusion, the simultaneous rapid recovery of lungs and preservation of abdominal organs with NRP in cDCD donors is feasible, and offers similar outcomes in both LuTx and LiTx recipients to transplants using DBD grafts.

Solid Phase Microextraction—A Promising Tool for Graft Quality Monitoring in Solid Organ Transplantation

Solid organ transplantation is a life-saving intervention for patients suffering from end-stage organ failure. Although improvements in surgical techniques, standards of care, and immunosuppression have been observed over the last few decades, transplant centers have to face the problem of an insufficient number of organs for transplantation concerning the growing demand. An opportunity to increase the pool of organs intended for transplantation is the more frequent use of organs from extended criteria and the development of analytical methods allowing for a better assessment of the quality of organs to minimize the risk of post-transplant organ injury and rejection. Therefore, solid-phase microextraction (SPME) has been proposed in various studies as an effective tool for determining compounds of significance during graft function assessment or for the chemical profiling of grafts undergoing various preservation protocols. This review summarizes how SPME addresses the analytical challenges associated with different matrices utilized in the peri-transplant period and discusses its potential as a diagnostic tool in future work.

Machine Perfusion for Extended Criteria Donor Livers: What Challenges Remain?

Based on the renaissance of dynamic preservation techniques, extended criteria donor (ECD) livers reclaimed a valuable eligibility in the transplantable organ pool. Being more vulnerable to ischemia, ECD livers carry an increased risk of early allograft dysfunction, primary non-function and biliary complications and, hence, unveiled the limitations of static cold storage (SCS). There is growing evidence that dynamic preservation techniques—dissimilar to SCS—mitigate reperfusion injury by reconditioning organs prior transplantation and therefore represent a useful platform to assess viability. Yet, a debate is ongoing about the advantages and disadvantages of different perfusion strategies and their best possible applications for specific categories of marginal livers, including organs from donors after circulatory death (DCD) and brain death (DBD) with extended criteria, split livers and steatotic grafts. This review critically discusses the current clinical spectrum of livers from ECD donors together with the various challenges and posttransplant outcomes in the context of standard cold storage preservation. Based on this, the potential role of machine perfusion techniques is highlighted next. Finally, future perspectives focusing on how to achieve higher utilization rates of the available donor pool are highlighted.

Preoperative portal vein recanalization-transjugular intrahepatic portosystemic shunt for chronic obliterative portal vein thrombosis: Outcomes following liver transplantation

High-grade portal vein thrombosis (PVT) is often considered to be a technically challenging scenario for liver transplantation (LT) and in some centers a relative contraindication. This study compares patients with chronic obliterative PVT who underwent portal vein recanalization-transjugular intrahepatic portosystemic shunt (PVR-TIPS) and subsequent LT to those with partial nonocclusive PVT who underwent LT without an intervention. This institutional review board-approved study analyzed 49 patients with cirrhosis with PVT from 2000 to 2020 at our institution. Patients were divided into two groups, those that received PVR-TIPS due to anticipated surgical challenges from chronic obliterative PVT and those who did not because of partial PVT. Demographic data and long-term outcomes were compared. A total of 35 patients received PVR-TIPS while 14 did not, with all receiving LT. Patients with PVR-TIPS had a higher Yerdel score and frequency of cavernoma than those that did not. PVR-TIPS was effective in decreasing portosystemic gradient (16 down to 8 mm HG; p < 0.05). Both groups allowed for end-to-end anastomoses in >90% of cases. However, veno-veno bypass was used significantly more in patients who did not receive PVR-TIPS. Additionally, patients without PVR-TIPS required significantly more intraoperative red blood cells. Overall survival was not different between groups. PVR-TIPS demonstrated efficacy in resolving PVT and allowed for end-to-end portal vein anastomoses. PVR-TIPS is a viable treatment option for chronic obliterative PVT with or without cavernoma that simplifies the surgical aspects of LT.

Utilization of dielectric properties for assessment of liver ischemia-reperfusion injury in vivo and during machine perfusion

There is a shortage of donor livers and patients consequently die on waiting lists worldwide. Livers are discarded if they are clinically judged to have a high risk of non-function following transplantation. With the aim of extending the pool of available donor livers, we assessed the condition of porcine livers by monitoring the microwave dielectric properties. A total of 21 livers were divided into three groups: control with no injury (CON), biliary injury by hepatic artery occlusion (AHEP), and overall hepatic injury by static cold storage (SCS). All were monitored for four hours in vivo, followed by ex vivo plurithermic machine perfusion (PMP). Permittivity data was modeled with a two-pole Cole–Cole equation, and dielectric properties from one-hour intervals were analyzed during in vivo and normothermic machine perfusion (NMP). A clear increasing trend in the conductivity was observed in vivo in the AHEP livers compared to the control livers. After four hours of NMP, separations in the conductivity were observed between the three groups. Our results indicate that dielectric relaxation spectroscopy (DRS) can be used to detect and differentiate liver injuries, opening for a standardized and reliable point of evaluation for livers prior to transplantation.

Decreasing Significance of Early Allograft Dysfunction with Rising Use of Nonconventional Donors

Background and Objectives: Early allograft dysfunction (EAD) is considered a surrogate marker for adverse post-liver transplant (LT) outcomes. With the increasing use of nonconventional donors, EAD has become a more frequent occurrence. Given this background, we aimed to assess the prevalence and impact of EAD in an updated cohort inclusive of both conventional and nonconventional liver allografts. Materials and Methods: Perioperative and one-year outcomes were assessed for a total of 611 LT recipients with and without EAD from Mayo Clinic Arizona. EAD was defined as the presence of one or more of the following: bilirubin > 10 mg/dL on day 7, INR > 1.6 on day 7, or ALT and/or AST > 2000 IU/L within the first 7 days of LT. Results: Within this cohort, 31.8% of grafts (n = 194) came from donation after circulatory death (DCD) donors, 17.7% (n = 108) were nationally shared, 16.4% (n = 100) were allocated as post-cross clamp, and 8.7% contained moderate steatosis. EAD was observed in 52.2% (n = 321) of grafts in the study cohort (79% in DCD grafts and 40% in DBD grafts). EAD grafts had higher donor risk index (DRI) scores (1.9 vs. 1.6, p < 0.0001), were more likely to come from DCD donors (48% vs. 13.8%, p < 0.0001), were regionally allocated (p = 0.003), and had higher cold ischemia times (median 6.0 vs. 5.5 h, p = 0.001). Primary nonfunction events were rare in both groups (1.3% vs. 0.3%, p = 0.22). Post-LT acute kidney injury occurred at a similar frequency in recipients with and without EAD (43.6% vs. 30.3%, p = 0.41), and there were no differences in ICU (median 2 vs. 1 day, p = 0.60) or hospital (6 vs. 5 days, p = 0.24) length of stay. For DCD grafts, the rate of ischemic cholangiopathy was similar in the two groups (14.9% EAD vs. 17.5% no EAD, p = 0.69). One-year patient survival for grafts with and without EAD was 96.0% and 94.1% (HR 1.2, 95% CI 0.7−1.8; p = 0.54); one-year graft survival was 92.5% and 92.1% (HR 1.0, 95% CI 0.7−1.5; p = 0.88). Conclusions: In this cohort, EAD occurred in 52% of grafts. The occurrence of EAD, however, did not portend inferior outcomes. Compared to those without EAD, recipients with EAD had similar post-operative outcomes, as well as one-year patient and graft survival. EAD should be managed supportively and should not be viewed as a deterrent to utilization of non-ideal grafts.

Does utilization of heart machine perfusion for donation after cardiac death transplantation affect outcomes of other abdominal transplanted organs?

INTRODUCTION

Machine perfusion of heart for donation after circulatory death (DCD) is being increasingly utilized. Current protocols for utilizing heart DCD's machine perfusion might prolong donor warm ischemic time for nonheart organs. The aim of this study was to analyze the effects of utilizing heart machine perfusion on liver and kidney transplants from the same donor.

METHODS

We analyzed data of DCD donors from the United Network for Organ Sharing (UNOS) from January-2020 to September-2021 among two groups: donors with heart machine perfusion (HM) and without heart machine perfusion (NHM). Propensity score (PS) matching was performed to compare the short-term outcomes of liver and kidney transplants between two groups.

RESULTS

Total of 102 liver and 319 kidney transplants were performed using organs from donors with HM. After PS matching, no statistically significant difference was seen in 1-year graft survival (GS) for both liver and kidney transplants between two groups (liver HM 90.6% vs. NHM 90.2%, p = .47; kidney HM 95.2% vs. NHM 92.9%, p = .40). There was no difference in the delayed graft function (DGF) rates in kidney transplantation (KT) (HM 42% vs. NHM 35%, p = .062).

CONCLUSION

Utilization of heart machine perfusion in DCD donors had no significant impact on 1-year outcomes of liver and kidney transplantation.

The volume - Outcomes relationship in donation after circulatory death liver transplantation

Background

Donation after circulatory death (DCD) liver transplantation (LT) has become an effective mechanism for expanding the donor pool and decreasing waitlist mortality. However, it is unclear if low‐volume DCD centers can achieve comparable outcomes to high‐volume centers.

Methods

From 2011 to 2019 utilizing the United Network for Organ Sharing (UNOS) database, liver transplant centers were categorized into tertiles based on their annual volume of DCD LTs. Donor selection, recipient selection, and survival outcomes were compared between very‐low volume (VLV, n = 1–2 DCD LTs per year), low‐volume (LV, n = 3–5), and high‐volume (HV, n > 5) centers.

Results

One hundred and ten centers performed 3273 DCD LTs. VLV‐centers performed 339 (10.4%), LV‐centers performed 627 (19.2%), and HV‐centers performed 2307 (70.4%) LTs. 30‐day, 90‐day, and 1‐year patient and graft survival were significantly increased at HV‐centers (all P < .05). Recipients at HV‐centers had shorter waitlist durations (P < .01) and shorter hospital lengths of stay (P < .01). On multivariable regression, undergoing DCD LT at a VLV‐center or LV‐center was associated with increased 1‐year patient mortality (VLV‐OR:1.73, 1.12–2.69) (LV‐OR: 1.42, 1.01–2.00) and 1‐year graft failure (VLV‐OR: 1.79, 1.24–2.58) (LV‐OR: 1.28, .95–1.72).

Discussion

Increased annual DCD liver transplant volume is associated with improved patient and graft survival.

Liver Transplantation in Recipients With Class III Obesity: Posttransplant Outcomes and Weight Gain

Background.

There has been a dramatic increase in obesity in the United States. Several studies have reported conflicting results for the impact of obesity on outcomes of liver transplantation (LT). This study aims to assess the impact of obesity on LT and changes in body mass index (BMI) after transplantation.

Methods.

All adult LTs performed at Indiana University between 2001 and 2018 were reviewed. BMIs of recipients were subdivided into 6 categories. Survival outcomes were compared across the subgroup. BMI was followed up in a cohort of patients from 2008 to 2018.

Results.

Among 2024 patients, 25% were in class I obesity, 9.3% were in class II obesity, and 1.1% were in class III obesity. There was no significant difference in patient and graft survival at 10-y follow-up with respect to BMI. Among 1004 patients in the subgroup, BMI of all groups except the underweight group declined in the first 3 mo postoperatively; however, the BMI of all groups except the class III obesity group returned to the pre-LT level by 2 y and reached a plateau by 5 y. In the class III obesity group, there was a significant increase in body weight at 5 y.

Conclusions.

Class III obesity was not associated with higher mortality in our cohort. Because our cohort is small, it may be underpowered to detect a smaller difference in outcome. From our observation, obesity should not be considered a contraindication for LT. Post-LT interventions are required to prevent significant weight gain for the class III obesity group.

The Prognostic Utility of Intraoperative Allograft Vascular Inflow Measurements in Donation After Circulatory Death Liver Transplantation

Donation after circulatory death (DCD) liver transplantation improves deceased donor liver use and decreases waitlist burden, albeit at an increased risk of biliary complications and inferior graft survival. Employing liver vascular inflow measurements intraoperatively permits allograft prognostication. However, its use in DCD liver transplantation is hitherto largely unknown and further explored here. DCD liver transplantation patient records at a single center from 2005 to 2018 were retrospectively scrutinized. Intraoperative flow data and relevant donor parameters were analyzed against endpoints of biliary events and graft survival. A total of 138 cases were chosen. The incidence of cumulative biliary complications was 38%, the majority of which were anastomotic strictures and managed successfully by endoscopic means. The ischemic cholangiopathy rate was 6%. At median thresholds of a portal vein (PV) flow rate of <92 mL/minute/100 g and buffer capacity (BC) of >0.04, both variables were independently associated with risk of biliary events (P = 0.01 and 0.04, respectively). Graft survival was 90% at 12 months and 75% at 5 years. Cox regression analysis revealed a PV flow rate of <50 mL/minute/100 g as predictive of poorer graft survival (P = 0.01). Furthermore, 126 of these DCD livers were analyzed against a propensity-matched group of 378 contemporaneous donation after brain death liver allografts (1:3), revealing significantly higher rates (P < 0.001) of both early allograft dysfunction (70% versus 30%) and biliary complications (37% versus 20%) in the former group. Although flow data were comparable between both sets, PV flow and BC were predictive of biliary events only in the DCD cohort. Intraoperative inflow measurements therefore provide valuable prognostication on biliary/graft outcomes in DCD liver transplantation, can help inform graft surveillance, and its routine use is recommended.

Ischemic Cholangiopathy Postdonation After Circulatory Death Liver Transplantation: Donor Hepatectomy Time Matters

Background.

Outcomes of liver transplantation (LT) from donation after circulatory death (DCD) have been improving; however, ischemic cholangiopathy (IC) continues to be a problem. In 2014, measures to minimize donor hepatectomy time (DHT) and cold ischemic time (CIT) have been adopted to improve DCD LT outcomes.

Methods.

Retrospective review of all patients who underwent DCD LT between 2005 and 2017 was performed. We compared outcomes of patients who were transplanted before 2014 (historic group) with those who were transplanted between 2014 and 2017 (modern group).

Results.

We identified 112 patients; 44 were in the historic group and 68 in the modern group. Donors in the historic group were younger (26.5 versus 33, P = 0.007) and had a lower body mass index (26.2 versus 28.2, P = 0.007). DHT (min) and CIT (h) were significantly longer in the historic group (21.5 versus 14, P < 0.001 and 5.3 versus 4.2, P < 0.001, respectively). Fourteen patients (12.5%) developed IC, with a significantly higher incidence in the historic group (23.3% versus 6.1%, P = 0.02). There was no difference in graft and patient survival between both groups.

Conclusion.

In appropriately selected recipients, minimization of DHT and CIT may decrease the incidence of IC. These changes can potentially expand the DCD donor pool.

Similar Results in Liver Transplantation From Controlled Donation After Circulatory Death Donors With Normothermic Regional Perfusion and Donation After Brain Death Donors: A Case-Matched Single-Center Study

Although good results have been reported with the use of normothermic regional perfusion (NRP) in controlled donation after circulatory death (cDCD) liver transplantation (LT), there is a lack of evidence to demonstrate similar results to donation after brain death (DBD). We present a single-center retrospective case-matched (1:2) study including 100 NRP cDCD LTs and 200 DBD LTs and a median follow-up of 36 months. Matching was done according to donor age, recipient Model for End-Stage Liver Disease score, and cold ischemia time. The following perioperative results were similar in both groups: alanine transaminase peaks of 909 U/L in the DBD group and 836 U/L in the cDCD group and early allograft disfunction percentages of 21% and 19.2%, respectively. The 1-year and 3-year overall graft survival for cDCD was 99% and 93%, respectively, versus 92% and 87%, respectively, for DBD (P = 0.04). Of note, no cases of primary nonfunction or ischemic-type biliary lesion were observed among the cDCD grafts. Our results confirm that NRP cDCD LT meets the same outcomes as those obtained with DBD LT and provides evidence to support the idea that cDCD donors per se should no longer be considered as "marginal donors" when recovered with NRP.

Patients with post-transplant biliary strictures have significantly higher rates of liver transplant failure and rejection: A nationwide inpatient analysis

BACKGROUND AND AIM

Biliary strictures are a common complication of liver transplantation. We assess the impact of post-transplant biliary strictures and describe the outcomes of endoscopic retrograde cholangiopancreatography (ERCP), interventional radiology (IR), and surgical therapies.

METHODS

Using the Nationwide Readmissions Database (NRD), hospitalized liver transplant recipients were identified using the International Classification of Diseases 10th Revision codes. Patients with post-transplant biliary strictures were identified, and outcomes (inpatient mortality, 30-day readmission, transplant rejection/infection/failure, and disposition) were compared with transplant recipients without strictures. Among transplant patients with biliary strictures who underwent therapeutic intervention, corresponding outcomes were compared between IR, surgical interventions, and ERCP.

RESULTS

Of the 8300 liver transplant recipients meeting selection criteria, 554 patients (age 48.9 ± 18.2 years, mean ± SD; 39.5% women) had biliary strictures. Compared with patients without strictures, the adjusted odds ratio (OR) for various outcomes in patients with biliary strictures were as follows: 1.46 (1.20, 1.77; P < 0.001) for 30-day non-elective readmission, 2.71 (2.04, 3.59; P < 0.001) allograft rejection, 2.32 (1.61, 3.37; P < 0.001) liver transplant failure, 3.05 (1.39, 6.73; P < 0.01) infection, and 1.41 (1.08, 1.82; P = 0.01) disposition to skilled nursing or intermediate care facility. Therapeutic interventions during index hospitalization were performed in 350 patients: ERCP 46.6% (n = 163), surgery 41% (n = 144), and IR 12.3% (n = 43) patients. Compared with ERCP, the adjusted odds for various outcomes were disposition to skilled nursing or intermediate care facility 2.72 (1.08, 6.87; P = 0.03) and 2.09 (1.05, 4.15; P = 0.036), prolongation of hospitalization 14.4 (3.7, 25.1; P = 0.008) and 15.0 (7.4, 22.7; P < 0.001), and failure of liver allograft 8.47 (1.47, 48.6; P = 0.017) and 12.23 (2.74, 54.4; P = 0.001) for IR and surgical interventions, respectively.

CONCLUSION

Post-liver transplant biliary strictures are associated with increased rates of allograft rejection, allograft failure/infections, and readmissions. Compared with ERCP, management of these patients with IR or surgical interventions is associated with significantly higher rates of allograft failure and hospital stay.

Donation after circulatory death and liver transplantation: a cohort study

Donations after circulatory death (DCD) are still challenging in Italy because of prolonged ischemia time (tWIT) due to the law and logistical issues. This cohort study was primarily aimed at assessing the association between successful transplantation and DCD types in the North Italy Transplant program. Adjusted risk ratios (RR) and 95% confidence intervals (CIs) for type III versus type II DCD were estimated using a Poisson regression model with a robust error variance. All consecutive DCD between 2008 and 2020 were included. Among 142 DCD, 102 were eligible for liver donation, and 96 were proposed: 68/69 (99%) and 28/33 (85%) type III and II DCD, respectively. Sixty-nine livers were recovered, 51/68 (75%) from type III and 18/28 (64%) from type II DCD, respectively (RR: 1.18; 95% CI: 0.87-1.60). After ex-vivo perfusion, 50/68 (74%) and 14/28 (50%) livers from type III and type II DCD were transplanted (RR: 1.49; 95% CI: 1.01-2.19). The estimate decreased after further controlling for tWIT (RR: 1.11; 95% CI: 0.55-2.24). Five patients (7.8%) experienced a PNF, 3/50 and 2/14 from type III and type II DCD, respectively. Type III DCD livers were more likely to be transplanted than type II. Warm ischemia time might explain this difference.

Evolving utilization of donation after circulatory death livers in liver transplantation: The day of DCD has come

Compared to donation after brain death (DBD), livers procured for transplantation from donation after circulatory death (DCD) donors experience more ischemia-reperfusion injury and higher rates of ischemic cholangiopathy due to the period of warm ischemic time (WIT) following withdrawal of life support. As a result, utilization of DCD livers for liver transplant (LT) has generally been limited to short WITs and younger aged donor grafts, causing many recovered DCD organs to be discarded without consideration for transplant. This study assesses how DCD liver utilization and outcomes have changed over time, using OPTN data from adult, first-time, deceased donor, whole-organ LTs between January 1995 and December 2019. Results show that increased clinical experience with DCD LT has translated into increased use of livers from DCD donors, shorter ischemic times, shorter lengths of hospitalization after transplant, and lower rates of retransplantation. The data also reveal that over the past decade, the rate of increase in DCD LTs conducted in the United States has outpaced that of DBD. Together, these trends signal an opportunity for the field of liver transplantation to mitigate the organ shortage by capitalizing on DCD liver allografts that are currently not being utilized.

Impact of donation after circulatory death donor allografts on outcomes following liver transplantation for fulminant hepatic failure in the United States

Limited data exist regarding the impact of donation after circulatory death (DCD) allografts on outcomes following liver transplantation in fulminant hepatic failure (FHF). Utilizing the Scientific Registry of Transplant Recipients (SRTR), we compared outcomes after DCD in FHF to donation after brain death (DBD) in FHF and DCD in non-FHF over a 15-year period. Primary outcome measures were graft and patient survival. A total of 117, 3437, and 4379 recipients underwent DCD-FHF, DBD-FHF and DCD-non-FHF, respectively. One-year graft survival in DCD-FHF was inferior to DBD-FHF (72.9% vs. 83.8%, p = .002), but comparable to DCD-non-FHF (72.9% vs. 82.7%, p = .23). However, 3- and 5-year graft survival in DCD-FHF were comparable to DBD-FHF (67.9 vs. 77.6%, p = .63; 57.8% vs. 73.2%, p = .27) and DCD-non-FHF (67.9% vs. 72.9%, p = .44; 57.8% vs. 66.6%, p = .06). One-, 3-, and 5-year patient survival were also comparable among the three groups. Graft and patient survival in DCD-FHF improved over the study period. Multivariable analysis identified recipient age, male gender, African American ethnicity, donor age, and cold ischemia time as predictors of graft and patient survival in FHF, while DCD status was only predictive of graft survival. Long-term graft survival and patient survival in DCD-FHF are comparable to DBD-FHF and DCD-non-FHF. Consideration of DCD in FHF could help expand the donor pool in this subset of critically ill patients.

Simultaneous liver-kidney transplantation from donation after cardiac death donors: an updated perspective

Outcomes of both donation after cardiac death (DCD) liver and kidney transplants are improving. Experience in simultaneous liver-kidney transplant (SLK) using DCD donors, however, remains limited. In an updated cohort (2010-2018), outcomes of 30 DCD SLK and 131 donation after brain death (DBD) SLK from Mayo Clinic Arizona and Mayo Clinic Minnesota were reviewed. The Model for End-Stage Liver Disease score was lower in the DCD SLK group (23 vs 29, P = .01). Kidney delayed graft function (DGF) rates were similar between the 2 groups (P = .11), although the duration of DGF was longer for DCD SLK recipients (20 vs 4 days, P = .01). Liver allograft (93.3% vs 93.1%, P = .29), kidney allograft (93.3% vs 93.1%, P = .91), and patient (96.7% vs 95.4%, P = .70) 1-year survival rates were similar. At 1 year, there were no differences in the estimated glomerular filtration rate (57.7 ± 18.2 vs 56.3 ± 17.7, P = .75) or progression of fibrosis (ci) on protocol kidney biopsy (P = .67). A higher incidence of biliary complications was observed in the DCD SLK group, with ischemic cholangiopathy being the most common (10.0% vs 0.0%, P = .03). The majority of biliary complications resolved with endoscopic management. With appropriate selection, DCD SLK recipients can have results equivalent to those of DBD SLK recipients.

Perioperative and long-term outcomes of utilizing donation after circulatory death liver grafts with macrosteatosis: A multicenter analysis

BACKGROUND

Given the potentially additive risk from using donor livers that are both steatotic and from a donation after circulatory death (DCD) donor, there is a paucity of data on the outcome of DCD liver transplantation (LT) utilizing livers with macrosteatosis.

METHODS

All DCD LT performed at Mayo Clinic-Florida, Mayo Clinic-Arizona, and Mayo Clinic-Rochester from 1999 to 2019 were included (N = 714). Recipients of DCD LT were divided into 3 groups: those with moderate macrosteatosis (30%-60%), mild macrosteatosis (5%-30%), and no steatosis (<5%).

RESULTS

Patients with moderate macrosteatosis had a higher rate of postreperfusion syndrome (PRS; 53.9% vs 26.2%; P = .002), postreperfusion cardiac arrest (7.7% vs 0.3%; P < .001), primary nonfunction (PNF; 7.7% vs 1.0%; P = .003), early allograft dysfunction (EAD; 70.8% vs 45.6% and 8.3%; P = .02), and acute kidney injury (AKI; 39.1% vs 19.4%; P = .02) than patients with no steatosis. No difference in any of the perioperative complications was seen between the mild macrosteatosis and the no steatosis groups except for the rate of EAD (56.8% vs 45.6%; P = .04). No difference in ischemic cholangiopathy (IC), vascular thrombosis/stenosis or graft, and patient survival was seen between the 3 groups.

CONCLUSION

DCD donors with mild macrosteatosis < 30% can be utilized with no increase in perioperative complications and similar patient and graft survival compared to DCD donors with no steatosis. When utilizing DCD donors with moderate macrosteatosis higher rates of PRS, PNF, postreperfusion cardiac arrest, EAD, and AKI should be anticipated.

The Changing Landscapes in DCD Liver Transplantation

Purpose of Review

The transplant community continues to look for ways to help address the discordance between donor liver graft availability and patients on the liver transplant waiting list. Donation after circulatory death (DCD) donor livers represents one potential means to help address this discordance. The present review describes the changing landscape of DCD liver transplantation (LT).

Recent Findings

The number of DCD LTs performed annually within the USA has continued to grow on an annual basis. Importantly, national data has demonstrated that outcomes with DCD LT have been improving. This improvement has been driven by better understanding of how to successfully utilize these organs through better donor and recipient matching and careful evaluation of both hemodynamics during withdrawal of life support and the refinement of the procurement operation.

Summary

Despite these improvements in outcome, ischemic cholangiopathy (IC) continues to be the Achilles heel of DCD LT. Emerging technologies such as various forms of machine perfusion may allow for reduction of complications and better prognostication of the risk associated with DCD liver grafts.

Impact of Recipient Age in Combined Liver-Kidney Transplantation: Caution Is Needed for Patients ≥70 Years

Elderly recipients (≥70 y) account for 2.6% of all liver transplants (LTs) in the United States and have similar outcomes as younger recipients. Although the rate of elderly recipients in combined liver-kidney transplant (CLKT) is similar, limited data are available on how elderly recipients perform after CLKT.

METHODS

We have previously shown excellent outcomes in CLKT using delayed kidney transplant (Indiana) Approach (mean kidney cold ischemia time = 53 ± 14 h). Between 2007 and 2018, 98 CLKTs were performed using the Indiana Approach at Indiana University (IU) and the data were retrospectively analyzed. Recipients were subgrouped based on their age: 18-45 (n = 16), 46-59 (n = 34), 60-69 (n = 40), and ≥70 years (n = 8).

RESULTS

Overall, more elderly patients received LT at IU (5.2%) when compared nationally (2.6%). The rate of elderly recipients in CLKT at IU was 8.2% (versus 2% Scientific Registry of Transplant Recipient). Recipient and donor characteristics were comparable between all age groups except recipient age and duration of dialysis. Patient survival at 1 and 3 years was similar among younger age groups, whereas patient survival was significantly lower in elderly recipients at 1 (60%) and 3 years (40%) (P = 0.0077). Control analyses (replicating Scientific Registry of Transplant Recipient's survival stratification: 18-45, 46-64, ≥65 y) showed similar patient survival in all age groups.

CONCLUSIONS

Although LT can be safely performed in elderly recipients, extreme caution is needed in CLKT due to the magnitude of operation.

Transplanting Marginal Organs in the Era of Modern Machine Perfusion and Advanced Organ Monitoring

Organ transplantation is undergoing profound changes. Contraindications for donation have been revised in order to better meet the organ demand. The use of lower-quality organs and organs with greater preoperative damage, including those from donation after cardiac death (DCD), has become an established routine but increases the risk of graft malfunction. This risk is further aggravated by ischemia and reperfusion injury (IRI) in the process of transplantation. These circumstances demand a preservation technology that ameliorates IRI and allows for assessment of viability and function prior to transplantation. Oxygenated hypothermic and normothermic machine perfusion (MP) have emerged as valid novel modalities for advanced organ preservation and conditioning. Ex vivo prolonged lung preservation has resulted in successful transplantation of high-risk donor lungs. Normothermic MP of hearts and livers has displayed safe (heart) and superior (liver) preservation in randomized controlled trials (RCT). Normothermic kidney preservation for 24 h was recently established. Early clinical outcomes beyond the market entry trials indicate bioenergetics reconditioning, improved preservation of structures subject to IRI, and significant prolongation of the preservation time. The monitoring of perfusion parameters, the biochemical investigation of preservation fluids, and the assessment of tissue viability and bioenergetics function now offer a comprehensive assessment of organ quality and function ex situ. Gene and protein expression profiling, investigation of passenger leukocytes, and advanced imaging may further enhance the understanding of the condition of an organ during MP. In addition, MP offers a platform for organ reconditioning and regeneration and hence catalyzes the clinical realization of tissue engineering. Organ modification may include immunological modification and the generation of chimeric organs. While these ideas are not conceptually new, MP now offers a platform for clinical realization. Defatting of steatotic livers, modulation of inflammation during preservation in lungs, vasodilatation of livers, and hepatitis C elimination have been successfully demonstrated in experimental and clinical trials. Targeted treatment of lesions and surgical treatment or graft modification have been attempted. In this review, we address the current state of MP and advanced organ monitoring and speculate about logical future steps and how this evolution of a novel technology can result in a medial revolution.

Biomarkers of Liver Injury during Transplantation in an Era of Machine Perfusion

Liver ischaemia–reperfusion injury (IRI) is an intrinsic part of the transplantation process and damages the parenchymal cells of the liver including hepatocytes, endothelial cells and cholangiocytes. Many biomarkers of IRI have been described over the past two decades that have attempted to quantify the extent of IRI involving different hepatic cellular compartments, with the aim to allow clinicians to predict the suitability of donor livers for transplantation. The advent of machine perfusion has added an additional layer of complexity to this field and has forced researchers to re-evaluate the utility of IRI biomarkers in different machine preservation techniques. In this review, we summarise the current understanding of liver IRI biomarkers and discuss them in the context of machine perfusion.