The UK DCD Risk Score: A new proposal to define futility in donation-after-circulatory-death liver transplantation

Xenogeneic cross-circulation for physiological support and recovery of ex vivo human livers

BACKGROUND AND AIMS

The scarcity of suitable donor livers highlights a continuing need for innovation to recover organs with reversible injuries in liver transplantation.

APPROACH AND RESULTS

Explanted human donor livers (n = 5) declined for transplantation were supported using xenogeneic cross-circulation of whole blood between livers and xeno-support swine. Livers and swine were assessed over 24 hours of xeno-support. Livers maintained normal global appearance, uniform perfusion, and preservation of histologic and subcellular architecture. Oxygen consumption increased by 75% ( p = 0.16). Lactate clearance increased from -0.4 ± 15.5% to 31.4 ± 19.0% ( p = 0.02). Blinded histopathologic assessment demonstrated improved injury scores at 24 hours compared with 12 hours. Vascular integrity and vasoconstrictive function were preserved. Bile volume and cholangiocellular viability markers improved for all livers. Biliary structural integrity was maintained.

CONCLUSIONS

Xenogeneic cross-circulation provided multisystem physiological regulation of ex vivo human livers that enabled functional rehabilitation, histopathologic recovery, and improvement of viability markers. We envision xenogeneic cross-circulation as a complementary technique to other organ-preservation technologies in the recovery of marginal donor livers or as a research tool in the development of advanced bioengineering and pharmacologic strategies for organ recovery and rehabilitation.

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

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

Early allograft dysfunction after living donor liver transplantation-current concepts and future directions

Early allograft dysfunction (EAD) after liver transplantation is a significant clinical problem that negatively impacts graft and patient outcomes. The rising incidence of EAD and what it means concerning living donor liver transplantation (LDLT) is an area of great interest. However, EAD after LDLT is a complex research topic yet to be reviewed comprehensively. Most of the literature on EAD is based on experience in deceased donor liver transplantation, and limited information is available in the context of LDLT. Thus, in this review, we present an overview of EAD after LDLT and have attempted to present balanced points of view on all its aspects, such as definitions, pathogenesis, risk factors, predictive markers, and management. The review aims to broadly overview the nature and extent of ongoing research evidence on this complex topic and inform practice in the field by identifying key concepts and knowledge gaps and highlighting areas that require further inquiry.

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 aimed to describe the outcomes of lung transplantation (LuTx) and liver transplantation (LiTx) when both grafts are simultaneously recovered from cDCD donors using NRP and compare them with grafts recovered from donation after brain death (DBD) donors. 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%) donors after cDCD with NRP and 1879 (21%) DBD donors (P < .001). Primary graft dysfunction grade-3 within the first 72 hours was similar in both LuTx groups (14.7% cDCD vs. 10.5% DBD; P = .139). LuTx survival at 1 and 3 years was 79.9% and 66.4% in cDCD vs. 81.9% and 69.7% in DBD (P = .403). The incidence of primary nonfunction and ischemic cholangiopathy was similar in both LiTx groups. Graft survival at 1 and 3 years was 89.7% and 80.8% in cDCD vs. 88.2% and 82.1% in DBD LiTx (P = .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.

Donation after circulatory death: Novel strategies to improve the liver transplant outcome

In many countries, donation after circulatory death (DCD) liver grafts are used to overcome organ shortages; however, DCD grafts have been associated with an increased risk of complications and even graft loss after liver transplantation. The increased risk of complications is thought to correlate with prolonged functional donor warm ischaemia time. Stringent donor selection criteria and utilisation of in situ and ex situ organ perfusion technologies have led to improved outcomes. Additionally, the increased use of novel organ perfusion strategies has led to the possibility of reconditioning marginal DCD liver grafts. Moreover, these technologies enable the assessment of liver function before implantation, thus providing valuable data that can guide more precise graft-recipient selection. In this review, we first describe the different definitions of functional warm donor ischaemia time and its role as a determinant of outcomes after DCD liver transplantation, with a focus on the thresholds proposed for graft acceptance. Next, organ perfusion strategies, namely normothermic regional perfusion, hypothermic oxygenated perfusion, and normothermic machine perfusion are discussed. For each technique, clinical studies reporting on the transplant outcome are described, together with a discussion on the possible protective mechanisms involved and the functional criteria adopted for graft selection. Finally, we review multimodal preservation protocols involving a combination of more than one perfusion technique and potential future directions in the field.

Simultaneous thoracic and abdominal donation after circulatory death organ recovery: the abdominal surgeon's perspective

PURPOSE OF THE REVIEW

To summarize the international experience with heart-liver (joint) donation after circulatory death (DCD) procurements and to explore the technical challenges in joint abdominal and thoracic DCD procurement.

RECENT FINDINGS

Following completion of the Donors After Circulatory Death Heart Trial in the US, combined thoracic and abdominal DCD is poised to become the standard of care, expanding access to life-saving heart and lung allografts. DCD heart procurement relies on collection of donor blood for priming of the normothermic perfusion pump, which delays cooling of abdominal organs and increases risk of ischemic injury. We review the effect of donor ischemia time on abdominal organs, with several proposed technical solutions to optimize transplant outcomes for all organs.

SUMMARY

The strategies reviewed in this manuscript may inform clinical decision-making, preoperative coordination between thoracic and abdominal procurement teams, and surgical technique for joint DCD procurements. Several approaches to organ procurement organization (OPO) and national policy, as well as future areas of focus for research are proposed.

Selecting DCD Recipients Using Predictive Indices

Donation after circulatory death (DCD) allografts might represent one of the largest untapped sources of liver allografts. Our aim was to identify independent recipient risk factors that predict mortality in DCD allograft recipients to preselect optimal candidates for successful transplantation. Furthermore, we compared the application of our newly constructed DCD Recipient Selector Index (RSI) score to previously developed models to determine superiority in predicting recipient survival.

Methods

Using the Organ Procurement and Transplantation Network database, we performed univariate and multivariate retrospective analyses on 4228 DCD liver allograft recipients.

Results

We identified 8 significant factors and incorporated them into the weighted RSI to predict 3-mo survival following DCD liver transplantation with a C-statistic of 0.6971. The most significant recipient risk factors were recipient serum sodium levels >150 mEq/L at transplant, recipient albumin <2.0 g/dL at transplant, and a history of portal vein thrombosis. Because Model for End-Stage Liver Disease (MELD) score components were included as individual predictors, the DCD RSI predicts survival independently of MELD. Upon comparison with 3 previous recipient risk scores-Balance of Risk, Renal Risk Index, Patient-Survival Outcomes Following Liver Transplantation-the DCD RSI was determined to be superior at selecting optimal candidates pre-DCD transplantation, yielding a C-statistic of 0.6971.

Conclusions

After verifying the performance of predictive indices for selection of DCD recipients, the DCD RSI is best used to preselect patients for optimized outcomes after DCD transplantation. This can increase utilization of DCD donors by improving outcomes.

Normothermic Regional Perfusion Can Improve Both Utilization and Outcomes in DCD Liver, Kidney, and Pancreas Transplantation

Normothermic regional perfusion (NRP) has gained widespread adoption in multiple European countries. The aim of this study was to examine the influence of thoracoabdominal-NRP (TA-NRP) on the utilization and outcomes of liver, kidney, and pancreas transplantation in the United States.

Methods

Using the US national registry data between 2020 and 2021, donation after circulatory death (DCD) donors were separated into 2 groups: DCD with TA-NRP and without TA-NRP. There were 5234 DCD donors; among them 34 donors were with TA-NRP. After 1:4 propensity score matching, the utilization rates were compared between DCD with and without TA-NRP.

Results

Although the utilization rates of kidney and pancreas were comparable (P = 0.71 and P = 0.06, 94.1% versus 95.6% and 8.8% versus 2.2%, respectively), that of liver in DCD with TA-NRP was significantly higher (P < 0.001; 70.6% versus 39.0%). Among 24 liver transplantations, 62 kidney transplantations, and 3 pancreas transplantations from DCD with TA-NRP, there were 2 liver grafts and 1 kidney graft that failed within 1 y after transplantation.

Conclusions

TA-NRP in the United States significantly increased the utilization rate of abdominal organs from DCD donors with comparable outcomes after transplantation. Increasing use of NRP may expand the donor pool without compromising transplant outcomes.

American Society of Transplant Surgeons recommendations on best practices in donation after circulatory death organ procurement

The American Society of Transplant Surgeons supports efforts to increase the number of organs that are critically needed for patients desperately awaiting transplantation. In the United States, transplantation using organs procured from donation after circulatory death (DCD) donors has continued to increase in number. Despite these increases, substantial variability in the utilization and practices of DCD transplantation still exists. To improve DCD organ utilization, it is important to create a set of best practices for DCD recovery. The following recommendations aim to provide guidance on contemporary issues surrounding DCD organ procurement in the United States. A work group was composed of members of the American Society of Transplant Surgeon Scientific Studies Committee and the Thoracic Organ Transplantation Committee. The following topics were identified by the group either as controversial or lacking standardization: prewithdrawal preparation, definition of donor warm ischemia time, DCD surgical technique, combined thoracic and abdominal procurements, and normothermic regional perfusion. The proposed recommendations were classified on the basis of the grade of available evidence and the strength of the recommendation. This information should be valuable for transplant programs as well as for organ procurement organizations and donor hospitals as they develop robust DCD donor procurement protocols.

The impact of perceived donor liver quality on post-transplant outcome

BACKGROUND

We analysed the impact of perceived liver donor quality on transplant recipient outcomes.

METHODS

this prospective cohort study included all deceased liver donors during 2008-2018 in the Swiss Transplant Cohort Study. Perceived low-quality liver donors were defined when refused for ≥5 top listed recipients or for all recipients in at least one centre before being transplanted. The effect of liver donor quality on relisting or recipient death at 1 week and 1 year after transplantation was analysed using Kaplan-Meier and Cox proportional hazard models. A 1:3 matching was also performed using a recipient score.

RESULTS

Of 973 liver donors, 187 (19.2%) had perceived poor-quality. Males, obesity, donation after circulatory death and alanine aminotransferase values were significantly associated with perceived poor-quality, with no significant effect of the perceived quality on re-listing or death within the first week and first year post-transplant [(aHR) = 1.45, 95% CI: (0.6, 3.5), P = 0.41 and aHR = 1.52 (95% CI 0.98-2.35), P = 0.06], adjusting by recipient age and gender, obesity, diabetes, prior liver transplantation and model for end-stage liver disease (MELD) score. At 1 year, prior liver transplantation and higher MELD score associated with higher risk of re-listing or death.

CONCLUSION

Comparable post-transplant outcomes with different perceived quality liver donors stresses the need to improve donor selection in liver transplantation.

Comparison of Biliary Complications Rates After Brain Death, Donation After Circulatory Death, and Living-Donor Liver Transplantation: A Single-Center Cohort Study

Donation-after-circulatory-death (DCD), donation-after-brain-death (DBD), and living-donation (LD) are the three possible options for liver transplantation (LT), each with unique benefits and complication rates. We aimed to compare DCD-, DBD-, and LD-LT-specific graft survival and biliary complications (BC). We collected data on 138 DCD-, 3,027 DBD- and 318 LD-LTs adult recipients from a single center and analyzed patient/graft survival. BC (leak and anastomotic/non-anastomotic stricture (AS/NAS)) were analyzed in a subset of 414 patients. One-/five-year graft survival were 88.6%/70.0% for DCD-LT, 92.6%/79.9% for DBD-LT, and, 91.7%/82.9% for LD-LT. DCD-LTs had a 1.7-/1.3-fold adjusted risk of losing their graft compared to DBD-LT and LD-LT, respectively (p < 0.010/0.403). Bile leaks were present in 10.1% (DCD-LTs), 7.2% (DBD-LTs), and 36.2% (LD-LTs) (ORs, DBD/LD vs. DCD: 0.7/4.2, p = 0.402/<0.001). AS developed in 28.3% DCD-LTs, 18.1% DBD-LTs, and 43.5% LD-LTs (ORs, DBD/LD vs. DCD: 0.5/1.8, p = 0.018/0.006). NAS was present in 15.2% DCD-LTs, 1.4% DBDs-LT, and 4.3% LD-LTs (ORs, DBD/LD vs. DCD: 0.1/0.3, p = 0.001/0.005). LTs w/o BC had better liver graft survival compared to any other groups with BC. DCD-LT and LD-LT had excellent graft survival despite significantly higher BC rates compared to DBD-LT. DCD-LT represents a valid alternative whose importance should increase further with machine/perfusion systems.

Predicting Early Allograft Function After Normothermic Machine Perfusion

BACKGROUND

Normothermic ex situ liver perfusion is increasingly used to assess donor livers, but there remains a paucity of evidence regarding criteria upon which to base a viability assessment or criteria predicting early allograft function.

METHODS

Perfusate variables from livers undergoing normothermic ex situ liver perfusion were analyzed to see which best predicted the Model for Early Allograft Function score.

RESULTS

One hundred fifty-four of 203 perfused livers were transplanted following our previously defined criteria. These comprised 84/123 donation after circulatory death livers and 70/80 donation after brain death livers. Multivariable analysis suggested that 2-h alanine transaminase, 2-h lactate, 11 to 29 mmol supplementary bicarbonate in the first 4 h, and peak bile pH were associated with early allograft function as defined by the Model for Early Allograft Function score. Nonanastomotic biliary strictures occurred in 11% of transplants, predominantly affected first- and second-order ducts, despite selection based on bile glucose and pH.

CONCLUSIONS

This work confirms the importance of perfusate alanine transaminase and lactate at 2-h, as well as the amount of supplementary bicarbonate required to keep the perfusate pH > 7.2, in the assessment of livers undergoing perfusion. It cautions against the use of lactate as a sole indicator of viability and also suggests a role for cholangiocyte function markers in predicting early allograft function.

Donation after circulatory death transplant outcomes using livers recovered by local surgeons

Donation after circulatory death (DCD) liver transplantation (LT) outcomes have been attributed to multiple variables, including procurement surgeon recovery techniques. Outcomes of 196 DCD LTs at Mayo Clinic Arizona were analyzed based on graft recovery by a surgeon from our center (transplant procurement team [TPT]) versus a local procurement surgeon (non-TPT [NTPT]). A standard recovery technique was used for all TPT livers. The recovery technique used by the NTPT was left to the discretion of that surgeon. A total of 129 (65.8%) grafts were recovered by our TPT, 67 (34.2%) by the NTPT. Recipient age (p = 0.43), Model for End-Stage Liver Disease score (median 17 vs. 18; p = 0.22), and donor warm ischemia time (median 21.0 vs. 21.5; p = 0.86) were similar between the TPT and NTPT groups. NTPT livers had longer cold ischemia times (6.5 vs. 5.0 median hours; p < 0.001). Early allograft dysfunction (80.6% vs. 76.1%; p = 0.42) and primary nonfunction (0.8% vs. 0.0%; p = 0.47) were similar. Ischemic cholangiopathy (IC) treated with endoscopy occurred in 18.6% and 11.9% of TPT and NTPT grafts (p = 0.23). At last follow-up, approximately half of those requiring endoscopy were undergoing a stent-free trial (58.3% TPT; 50.0% NTPT; p = 0.68). IC requiring re-LT in the first year occurred in 0.8% (n = 1) of TPT and 3.0% (n = 2) of NTPT grafts (p = 0.23). There were no differences in patient (hazard ratio [HR], 1.95; 95% confidence interval [CI], 0.76-5.03; p = 0.23) or graft (HR, 1.99; 95% CI, 0.98-4.09; p = 0.10) survival rates. Graft survival at 1 year was 91.5% for TPT grafts and 95.5% for NTPT grafts. Excellent outcomes can be achieved using NTPT for the recovery of DCD livers. There may be an opportunity to expand the use of DCD livers in the United States by increasing the use of NTPT.

In situ normothermic regional perfusion versus ex situ normothermic machine perfusion in liver transplantation from donation after circulatory death

In situ normothermic regional perfusion (NRP) and ex situ normothermic machine perfusion (NMP) aim to improve the outcomes of liver transplantation (LT) using controlled donation after circulatory death (cDCD). NRP and NMP have not yet been compared directly. In this international observational study, outcomes of LT performed between 2015 and 2019 for organs procured from cDCD donors subjected to NRP or NMP commenced at the donor center were compared using propensity score matching (PSM). Of the 224 cDCD donations in the NRP cohort that proceeded to asystole, 193 livers were procured, resulting in 157 transplants. In the NMP cohort, perfusion was commenced in all 40 cases and resulted in 34 transplants (use rates: 70% vs. 85% [p = 0.052], respectively). After PSM, 34 NMP liver recipients were matched with 68 NRP liver recipients. The two cohorts were similar for donor functional warm ischemia time (21 min after NRP vs. 20 min after NMP; p = 0.17), UK-Donation After Circulatory Death risk score (5 vs. 5 points; p = 0.38), and laboratory Model for End-Stage Liver Disease scores (12 vs. 12 points; p = 0.83). The incidence of nonanastomotic biliary strictures (1.5% vs. 2.9%; p > 0.99), early allograft dysfunction (20.6% vs. 8.8%; p = 0.13), and 30-day graft loss (4.4% vs. 8.8%; p = 0.40) were similar, although peak posttransplant aspartate aminotransferase levels were higher in the NRP cohort (872 vs. 344 IU/L; p < 0.001). NRP livers were more frequently allocated to recipients suffering from hepatocellular carcinoma (HCC; 60.3% vs. 20.6%; p < 0.001). HCC-censored 2-year graft and patient survival rates were 91.5% versus 88.2% (p = 0.52) and 97.9% versus 94.1% (p = 0.25) after NRP and NMP, respectively. Both perfusion techniques achieved similar outcomes and appeared to match benchmarks expected for donation after brain death livers. This study may inform the design of a definitive trial.

Transplantation of a human liver following 3 days of ex situ normothermic preservation

Current organ preservation methods provide a narrow window (usually <12 hours) to assess, transport and implant donor grafts for human transplantation. Here we report the transplantation of a human liver discarded by all centers, which could be preserved for several days using ex situ normothermic machine perfusion. The transplanted liver exhibited normal function, with minimal reperfusion injury and the need for only a minimal immunosuppressive regimen. The patient rapidly recovered a normal quality of life without any signs of liver damage, such as rejection or injury to the bile ducts, according to a 1-year follow up. This inaugural clinical success opens new horizons in clinical research and promises an extended time window of up to 10 days for assessment of viability of donor organs as well as converting an urgent and highly demanding surgery into an elective procedure.

Use of preprocurement biopsy in donation after circulatory death liver transplantation

We perform routine preprocurement image-guided percutaneous liver biopsies on potential donation after circulatory death (DCD) liver donors. The purpose of this study was to examine the impact of preprocurement liver biopsy on the use of livers from DCD donors. We retrospectively reviewed demographics, liver histology, and disposition of DCD liver donors within a single organ procurement organization (OPO) who underwent preprocurement liver biopsy from January 2000 through December 2019. A total of 212 potential donors underwent prerecovery biopsy. No donors were lost as a result of complications of biopsy. Of these, 183 (86.3%) had acceptable biopsies: 146 (79.8%) were successfully transplanted and 37 (20.2%) were deemed not suitable for transplant. In contrast, of 120 DCD livers recovered with the intent to transplant that were not biopsied prior to recovery, 59 (49.2%) were successfully transplanted, and 61 (50.8%) were deemed not suitable for transplant. A total of 14 donors were ruled out for transplant based on prerecovery histology. Successfully transplanted livers that underwent preprocurement biopsy were more likely to come from donors aged older than 50 years or with body mass index more than 30 kg/m² compared with successfully transplanted livers without a prerecovery biopsy. Biopsy excluded 6.6% of DCD donor livers for transplant prior to recovery and facilitated the successful recovery and transplant of two-thirds of potential DCD donor livers. Livers intended for transplant at the time of recovery that did not undergo preprocurement biopsy were more likely to not be recovered or to be discarded. Preprocurement biopsy provides additional histologic information prior to deploying resources and helps to identify usable livers that might otherwise be declined for transplant. Consideration of liver biopsy in this group benefits OPOs and transplant centers by maximizing organ use and optimizing resource deployment.

Disparities in the Effects of Acuity Circle-based Liver Allocation on Waitlist and Transplant Practice Between Centers

Liver allocation in the United States was updated on February 4, 2020, by introducing the acuity circle (AC)-based model. This study evaluated the early effects of the AC-based allocation on waitlist outcomes.

Methods

Adult liver transplant (LT) candidates listed between January 1, 2019, and September 30, 2021, were assessed. Two periods were defined according to listing date (pre- and post-AC), and 90-d waitlist outcomes were compared. Median transplant Model for End-stage Liver Disease (MELD) score of each transplant center was calculated, with centers categorized as low- (<25 percentile), mid- (25-75 percentile), and high-MELD (>75 percentile) centers.

Results

A total of 12 421 and 17 078 LT candidates in the pre- and post-AC eras were identified. Overall, the post-AC era was associated with higher cause-specific 90-d hazards of transplant (csHR, 1.32; 95% confidence interval [CI], 1.27-1.38; P < 0.001) and waitlist mortality (cause-specific hazard ratio [csHR], 1.20; 95% CI, 1.09-1.32; P < 0.001). The latter effect was primarily driven by high-MELD centers. Low-MELD centers had a higher proportion of donations after circulatory death (DCDs) used. Compared with low-MELD centers, mid-MELD and high-MELD centers had significantly lower cause-specific hazards of DCD-LT in both eras (mid-MELD: csHR, 0.47; 95% CI, 0.38-0.59 in pre-AC and csHR, 0.56; 95% CI, 0.46-0.67 in post-AC and high-MELD: csHR, 0.11; 95% CI, 0.07-0.17 in pre-AC and csHR, 0.14; 95% CI, 0.10-0.20 in post-AC; all P < 0.001). Using a structural Bayesian time-series model, the AC policy was associated with an increase in the actual monthly DCD-LTs in low-, mid-, and high-MELD centers (actual/predicted: low-MELD: 19/16; mid-MELD: 21/14; high-MELD: 4/3), whereas the increase in monthly donation after brain death-LTs were only present in mid- and high-MELD centers.

Conclusions

Although AC-based allocation may improve waitlist outcomes, regional variation exists in the drivers of such outcomes between centers.

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.

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.

Utilization of elderly donors in liver transplantation for patients with hepatocellular carcinoma: A national retrospective cohort study of China

BACKGROUND

Profound organ shortages worldwide have led to the increased utilization of marginal organs from older individuals. However, the effectiveness of liver transplantation (LT) with organs from elderly donors for patients with hepatocellular carcinoma (HCC) remains controversial. The objective of the current study was to assess the overall survival (OS) and disease-free survival (DFS) of patients with HCC following LT using grafts from deceased donors over 60 years old.

MATERIAL AND METHODS

Patients with HCC who underwent LT between 2015 and 2018 were identified in the China Liver Transplant Registry database. The overall survival and disease-free survival of older liver donors (OLDs) were compared with those of younger liver donors (YLDs) after propensity score matching.

RESULTS

From January 2015 to December 2018, a total of 4971 HCC patients were enrolled in the study according to the screening criteria. The absolute and relative utilization of liver grafts from elderly patients over 60 years for HCC patients increased every year, from 65 (9.3%) in 2015 to 268 (14.5%) in 2018. Disease-free survival (DFS) was significantly lower in HCC patients with elderly donors (both P < 0.05) after propensity score matching. The OLD group had worse DFS than YLD group if patients had tumors beyond the Milan criteria (P < 0.05).

CONCLUSIONS

The use of older donors for LT has been growing quickly in the last few years in China. Grafts from older donors can be safely used in HCC recipients with similar OS and comparable perioperative complications. However, further investigation into whether older donor has an impact on recurrence is warranted, especially among those with tumors beyond the Milan criteria.

Liver perfusion strategies: what is best and do ischemia times still matter?

PURPOSE OF REVIEW

This review describes recent developments in the field of liver perfusion techniques.

RECENT FINDINGS

Dynamic preservation techniques are increasingly tested due to the urgent need to improve the overall poor donor utilization. With their exposure to warm ischemia, livers from donors after circulatory death (DCD) transmit additional risk for severe complications after transplantation. Although the superiority of dynamic approaches compared to static-cold-storage is widely accepted, the number of good quality studies remains limited. Most risk factors, particularly donor warm ischemia, and accepted thresholds are inconsistently reported, leading to difficulties to assess the impact of new preservation technologies. Normothermic regional perfusion (NRP) leads to good outcomes after DCD liver transplantation, with however short ischemia times. While randomized controlled trials (RCT) with NRP are lacking, results from the first RCTs with ex-situ perfusion were reported. Hypothermic oxygenated perfusion was shown to protect DCD liver recipients from ischemic cholangiopathy. In contrast, endischemic normothermic perfusion seems to not impact on the development of biliary complications, although this evidence is only available from retrospective studies.

SUMMARY

Dynamic perfusion strategies impact posttransplant outcomes and are increasingly commissioned in various countries along with more evidence from RCTs. Transparent reporting of risk and utilization with uniform definitions is required to compare the role of different preservation strategies in DCD livers with prolonged ischemia times.

Impact of the donor hepatectomy time on short-term outcomes in liver transplantation using donation after circulatory death: A review of the US national registry

BACKGROUND

During the donor hepatectomy time (dHT), defined as the time from the start of cold perfusion to the end of the hepatectomy, liver grafts have a suboptimal temperature. The aim of this study was to analyze the impact of prolonged dHT on outcomes in donation after circulatory death (DCD) liver transplantation (LT).

METHODS

Using the US national registry data between 2012 and 2020, DCD LT patients were separated into 2 groups based on their dHT: standard dHT (<42 min) and prolonged dHT (≥42 min).

RESULTS

There were 3810 DCD LTs during the study period. Median dHT was 32 min (IQR 25-41 min). Kaplan- Meier graft survival curves demonstrated inferior outcomes in the prolonged dHT group at 1-year after DCD LT compared to those in the standard dHT group (85.3% vs 89.9%; p < 0.01). Multivariate Cox proportional hazards models for 1-year graft survival identified that prolonged dHT [hazard ratio (HR) 1.46, 95% confidence interval (CI) 1.19 - 1.79], recipient age ≥ 64 years (HR 1.40, 95% CI 1.14 - 1.72), and MELD score ≥ 24 (HR 1.43, 95% CI 1.16 - 1.76) were significant predictors of 1-year graft loss. Spline analysis shows that the dHT effects on the risk for 1-year graft loss with an increase in the slope after median dHT of 32 min.

CONCLUSION

Prolonged dHTs significantly reduced graft and patient survival after DCD LT. Because dHT is a modifiable factor, donor surgeons should take on cases with caution by setting the dHT target of < 32 min. This article is protected by copyright. All rights reserved.

Salvage of Declined Extended Criteria DCD Livers Using in-situ Normothermic Regional Perfusion

OBJECTIVE

This study investigates whether liver grafts donated after circulatory death (DCD) that are declined by the entire Euro-transplant region can be salvaged with abdominal normothermic regional perfusion (aNRP).

SUMMARY BACKGROUND DATA

aNRP is increasingly used for DCD liver grafts because it prevents typical complications. However, it is unclear whether aNRP is capable to rescue pre-transplant declined liver grafts, by providing the opportunity to test function during donation.

METHODS

Donor livers from DCD donors, declined by all centers in the Euro-transplant region, were included for this study. The comparator cohort included standard DCD livers and livers donated after brain death, transplanted in the same time period.

RESULTS

After withdrawal of life-sustaining treatment, 28 from the 43 donors had a circulatory death within 2 hours, in which case aNRP was initiated. Out of these 28 cases, in 3 cases perfusion problems occurred, 5 grafts were declined based on liver assessment, and 20 liver grafts were transplanted. The main differences during aNRP between the transplanted grafts and the assessed non-transplanted grafts were ALT levels of 53 (34-68) versus 367 (318-488; P=0.001) U/l and bile production in 100% versus 50% of the grafts (P=0.024). The 12-month graft and patient survival were both 95%, similar to the comparator cohort. The incidence of ischemic cholangiopathy was 11%, which was lower than in the standard DCD cohort (18%).

CONCLUSIONS

aNRP can safely select and thus is able to rescue DCD liver grafts that were deemed unsuitable for transplantation, while preventing primary non-function and minimizing ischemic cholangiopathy.

The Implication of Center Volumes in Donation After Circulatory Death for Liver Transplantation: Donor-Recipient Selection and Outcomes

BACKGROUND

The use of donation after circulatory death liver transplant (DCD LT) has increased and the outcomes have improved. There are little data concerning the details of centers' practice.

METHODS

Using the United Network for Organ Sharing Standard Transplant Analysis and Research data, the centers were stratified into 4 quartiles: lowest-, low-, high-, and highest-volume quartiles.

RESULTS

High-risk donors, defined as older donors (≥50 years) or obese donors (body mass index ≥ 30 kg/m²), linearly increased in line with the centers' volumes (P < .001), while cold ischemia time (CIT) showed an inverse correlation (P < .001). High-risk recipients, defined as those with high Model for End-stage Liver Disease score, re-LT, inpatient, or ventilator/dialysis before LT, did not show any significant difference (P = .74) except in the highest-volume quartile (P < .001). One-year graft survival showed a bimodal pattern across the 4 quartiles (P = .027): superior graft survival in the highest-volume quartile and in the low-volume quartile and inferior graft survival in the high-volume quartile and in the lowest-volume quartile.

CONCLUSIONS

High-risk donors can achieve satisfactory outcomes by being matched with low-risk recipients and shortening CIT. However, high-risk recipients may not result in favorable outcomes with DCD LT even with centers' experience and shorter CIT.

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.

Disparities in the Use of Older Donation After Circulatory Death Liver Allografts in the United States Versus the United Kingdom

BACKGROUND

This study aimed to assess the differences between the United States and the United Kingdom in the characteristics and posttransplant survival of patients who received donation after circulatory death (DCD) liver allografts from donors aged >60 y.

METHODS

Data were collected from the UK Transplant Registry and the United Network for Organ Sharing databases. Cohorts were dichotomized into donor age subgroups (donor >60 y [D >60]; donor ≤60 y [D ≤60]). Study period: January 1, 2001, to December 31, 2015.

RESULTS

1157 DCD LTs were performed in the United Kingdom versus 3394 in the United States. Only 13.8% of US DCD donors were aged >50 y, contrary to 44.3% in the United Kingdom. D >60 were 22.6% in the United Kingdom versus 2.4% in the United States. In the United Kingdom, 64.2% of D >60 clustered in 2 metropolitan centers. In the United States, there was marked inter-regional variation. A total of 78.3% of the US DCD allografts were used locally. One- and 5-y unadjusted DCD graft survival was higher in the United Kingdom versus the United States (87.3% versus 81.4%, and 78.0% versus 71.3%, respectively; P < 0.001). One- and 5-y D >60 graft survival was higher in the United Kingdom (87.3% versus 68.1%, and 77.9% versus 51.4%, United Kingdom versus United States, respectively; P < 0.001). In both groups, grafts from donors ≤30 y had the best survival. Survival was similar for donors aged 41 to 50 versus 51 to 60 in both cohorts.

CONCLUSIONS

Compared with the United Kingdom, older DCD LT utilization remained low in the United States, with worse D >60 survival. Nonetheless, present data indicate similar survivals for older donors aged ≤60, supporting an extension to the current US DCD age cutoff.

Normothermic Regional Perfusion and Hypothermic Oxygenated Machine Perfusion for Livers Donated After Controlled Circulatory Death With Prolonged Warm Ischemia Time: A Matched Comparison With Livers From Brain-Dead Donors

Prolonged warm ischemia time (WIT) has a negative prognostic value in liver transplantation (LT) using grafts procured after circulatory death (DCD). To assess the value of abdominal normothermic regional perfusion (A-NRP) associated with dual hypothermic oxygenated machine perfusion (D-HOPE) in controlled DCD LT, prospectively collected data on LTs performed between January 2016 and July 2021 were analyzed. Outcome of controlled DCD LTs performed using A-NRP + D-HOPE (n = 20) were compared to those performed with grafts procured after brain death (DBD) (n = 40), selected using propensity-score matching. DCD utilization rate was 59.5%. In the DCD group, median functional WIT, A-NRP and D-HOPE time was 43, 246, and 205 min, respectively. Early outcomes of DCD grafts recipients were comparable to those of matched DBD LTs. In DCD and DBD group, incidence of anastomotic biliary complications and ischemic cholangiopathy was 15% versus 22% (p = 0.73) and 5% versus 2% (p = 1), respectively. One-year patient and graft survival was 100% versus 95% (p = 0.18) and 90% versus 95% (p = 0.82). In conclusion, the association of A-NRP + D-HOPE in DCD LT with prolonged WIT allows achieving comparable outcomes to DBD LT.

Introduction of the Concept of Diagnostic Sensitivity and Specificity of Normothermic Perfusion Protocols to Assess High-Risk Donor Livers

Normothermic machine perfusion (NMP) allows objective assessment of donor liver transplantability. Several viability evaluation protocols have been established, consisting of parameters such as perfusate lactate clearance, pH, transaminase levels, and the production and composition of bile. The aims of this study were to assess 3 such protocols, namely, those introduced by the teams from Birmingham (BP), Cambridge (CP), and Groningen (GP), using a cohort of high-risk marginal livers that had initially been deemed unsuitable for transplantation and to introduce the concept of the viability assessment sensitivity and specificity. To demonstrate and quantify the diagnostic accuracy of these protocols, we used a composite outcome of organ use and 24-month graft survival as a surrogate endpoint. The effects of assessment modifications, including the removal of the most stringent components of the protocols, were also assessed. Of the 31 organs, 22 were transplanted after a period of NMP, of which 18 achieved the outcome of 24-month graft survival. The BP yielded 94% sensitivity and 50% specificity when predicting this outcome. The GP and CP both seemed overly conservative, with 1 and 0 organs, respectively, meeting these protocols. Modification of the GP and CP to exclude their most stringent components increased this to 11 and 8 organs, respectively, and resulted in moderate sensitivity (56% and 44%) but high specificity (92% and 100%, respectively) with respect to the composite outcome. This study shows that the normothermic assessment protocols can be useful in identifying potentially viable organs but that the balance of risk of underuse and overuse varies by protocol.

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.

Proposal and validation of a liver graft discard score for liver transplantation from deceased donors: a multicenter Italian study

Several studies have explored the risk of graft dysfunction after liver transplantation (LT) in recent years. Conversely, risk factors for graft discard before or at procurement have poorly been investigated. The study aimed at identifying a score to predict the risk of liver-related graft discard before transplantation. Secondary aims were to test the score for prediction of biopsy-related negative features and post-LT early graft loss. A total of 4207 donors evaluated during the period January 2004-Decemeber 2018 were retrospectively analyzed. The group was split into a training set (n = 3,156; 75.0%) and a validation set (n = 1,051; 25.0%). The Donor Rejected Organ Pre-transplantation (DROP) Score was proposed: - 2.68 + (2.14 if Regional Share) + (0.03*age) + (0.04*weight)-(0.03*height) + (0.29 if diabetes) + (1.65 if anti-HCV-positive) + (0.27 if HBV core) - (0.69 if hypotension) + (0.09*creatinine) + (0.38*log10AST) + (0.34*log10ALT) + (0.06*total bilirubin). At validation, the DROP Score showed the best AUCs for the prediction of liver-related graft discard (0.82; p < 0.001) and macrovesicular steatosis ≥ 30% (0.71; p < 0.001). Patients exceeding the DROP 90th centile had the worse post-LT results (3-month graft loss: 82.8%; log-rank P = 0.024).The DROP score represents a valuable tool to predict the risk of liver function-related graft discard, steatosis, and early post-LT graft survival rates. Studies focused on the validation of this score in other geographical settings are required.

Abdominal normothermic regional perfusion in controlled donation after circulatory determination of death liver transplantation: Outcomes and risk factors for graft loss

Postmortem normothermic regional perfusion (NRP) is a rising preservation strategy in controlled donation after circulatory determination of death (cDCD). Herein, we present results for cDCD liver transplants performed in Spain 2012-2019, with outcomes evaluated through December 31, 2020. Results were analyzed retrospectively and according to recovery technique (abdominal NRP [A-NRP] or standard rapid recovery [SRR]). During the study period, 545 cDCD liver transplants were performed with A-NRP and 258 with SRR. Median donor age was 59 years (interquartile range 49-67 years). Adjusted risk estimates were improved with A-NRP for overall biliary complications (OR 0.300, 95% CI 0.197-0.459, p < .001), ischemic type biliary lesions (OR 0.112, 95% CI 0.042-0.299, p < .001), graft loss (HR 0.371, 95% CI 0.267-0.516, p < .001), and patient death (HR 0.540, 95% CI 0.373-0.781, p = .001). Cold ischemia time (HR 1.004, 95% CI 1.001-1.007, p = .021) and re-transplantation indication (HR 9.552, 95% CI 3.519-25.930, p < .001) were significant independent predictors for graft loss among cDCD livers with A-NRP. While use of A-NRP helps overcome traditional limitations in cDCD liver transplantation, opportunity for improvement remains for cases with prolonged cold ischemia and/or technically complex recipients, indicating a potential role for complimentary ex situ perfusion preservation techniques.

Donation after Circulatory Death Liver Transplantation in Paediatric Recipients

Waiting list mortality together, with limited availability of organs, are one of the major challenges in liver transplantation (LT). Especially in the paediatric population, another limiting factor is the scarcity of transplantable liver grafts due to additional concerns regarding graft size matching. In adults, donation after circulatory death (DCD) liver grafts have been used to expand the donor pool with satisfactory results. Although several studies suggest that DCD livers could also be used in paediatric recipients with good outcomes, their utilisation in children is still limited to a small number of reports. Novel organ perfusion strategies could be used to improve organ quality and help to increase the number of DCD grafts utilised for children. With the current manuscript, we present the available literature of LT using DCD grafts in paediatric recipients, discussing current challenges with the use of these livers in children and how machine perfusion technologies could be of impact in the future.

Liver Transplantation Outcomes From Controlled Circulatory Death Donors: Static cold storage vs in situ normothermic regional perfusion vs ex situ normothermic machine perfusion

OBJECTIVE

To compare the outcomes of livers donated after circulatory death (DCD) and undergoing either in situ normothermic regional perfusion (NRP) or ex situ normothermic machine perfusion (NMP) with livers undergoing static cold storage (SCS).

SUMMARY OF BACKGROUND DATA

DCD livers are associated with increased risk of primary nonfunction, poor function, and nonanastomotic strictures (NAS), leading to underutilization.

METHODS

A single center, retrospective analysis of prospectively collected data on 233 DCD liver transplants performed using SCS, NRP, or NMP between January 2013 and October 2020.

RESULTS

Ninety-seven SCS, 69 NRP, and 67 NMP DCD liver transplants were performed, with 6-month and 3-year transplant survival (graft survival noncensored for death) rates of 87%, 94%, 90%, and 76%, 90%, and 76%, respectively. NRP livers had a lower 6-month risk-adjusted Cox proportional hazard for transplant failure compared to SCS (hazard ratio 0.30, 95%CI 0.08-1.05, P = 0.06). NRP and NMP livers had a risk-adjusted estimated reduction in the mean model for early allograft function score of 1.52 (P < 0.0001) and 1.19 (P < 0.001) respectively compared to SCS. Acute kidney injury was more common with SCS (55% vs 39% NRP vs 40% NMP; P = 0.08), with a lower risk-adjusted peak-to-baseline creatinine ratio in the NRP (P = 0.02). No NRP liver had clinically significant NAS in contrast to SCS (14%) and NMP (11%, P = 0.009), with lower risk-adjusted odds of overall NAS development compared to SCS (odds ratio = 0.2, 95%CI 0.06-0.72, P = 0.01).

CONCLUSION

NRP and NMP were associated with better early liver function compared to SCS, whereas NRP was associated with superior preservation of the biliary system.

A multicentre outcome analysis to define global benchmarks for donation after circulatory death liver transplantation

BACKGROUND & AIMS

The concept of benchmarking is established in the field of transplant surgery; however, benchmark values for donation after circulatory death (DCD) liver transplantation are not available. Thus, we aimed to identify the best possible outcomes in DCD liver transplantation and to propose outcome reference values.

METHODS

Based on 2,219 controlled DCD liver transplantations, collected from 17 centres in North America and Europe, we identified 1,012 low-risk, primary, adult liver transplantations with a laboratory MELD score of ≤20 points, receiving a DCD liver with a total donor warm ischemia time of ≤30 minutes and asystolic donor warm ischemia time of ≤15 minutes. Clinically relevant outcomes were selected and complications were reported according to the Clavien-Dindo-Grading and the comprehensive complication index (CCI). Corresponding benchmark cut-offs were based on median values of each centre, where the 75th-percentile was considered.

RESULTS

Benchmark cases represented between 19.7% and 75% of DCD transplantations in participating centres. The 1-year retransplant and mortality rates were 4.5% and 8.4% in the benchmark group, respectively. Within the first year of follow-up, 51.1% of recipients developed at least 1 major complication (≥Clavien-Dindo-Grade III). Benchmark cut-offs were ≤3 days and ≤16 days for ICU and hospital stay, ≤66% for severe recipient complications (≥Grade III), ≤16.8% for ischemic cholangiopathy, and ≤38.9 CCI points 1 year after transplant. Comparisons with higher risk groups showed more complications and impaired graft survival outside the benchmark cut-offs. Organ perfusion techniques reduced the complications to values below benchmark cut-offs, despite higher graft risk.

CONCLUSIONS

Despite excellent 1-year survival, morbidity in benchmark cases remains high. Benchmark cut-offs targeting morbidity parameters offer a valid tool to assess the protective value of new preservation technologies in higher risk groups and to provide a valid comparator cohort for future clinical trials.

LAY SUMMARY

The best possible outcomes after liver transplantation of grafts donated after circulatory death (DCD) were defined using the concept of benchmarking. These were based on 2,219 liver transplantations following controlled DCD donation in 17 centres worldwide. Donor and recipient combinations with higher risk had significantly worse outcomes. However, the use of novel organ perfusion technology helped high-risk patients achieve similar outcomes as the benchmark cohort.

Advantages and Limitations of Clinical Scores for Donation After Circulatory Death Liver Transplantation

Background: Scoring systems have been proposed to select donation after circulatory death (DCD) donors and recipients for liver transplantation (LT). We hypothesized that complex scoring systems derived in large datasets might not predict outcomes locally. Methods: Based on 1-year DCD-LT graft survival predictors in multivariate logistic regression models, we designed, validated, and compared a simple index using the University of California, San Francisco (UCSF) cohort (n = 136) and a universal-comprehensive (UC)-DCD score using the United Network for Organ Sharing (UNOS) cohort (n = 5,792) to previously published DCD scoring systems. Results: The total warm ischemia time (WIT)-index included donor WIT (dWIT) and hepatectomy time (dHep). The UC-DCD score included dWIT, dHep, recipient on mechanical ventilation, transjugular-intrahepatic-portosystemic-shunt, cause of liver disease, model for end-stage liver disease, body mass index, donor/recipient age, and cold ischemia time. In the UNOS cohort, the UC-score outperformed all previously published scores in predicting DCD-LT graft survival (AUC: 0.635 vs. ≤0.562). In the UCSF cohort, the total WIT index successfully stratified survival and biliary complications, whereas other scores did not. Conclusion: DCD risk scores generated in large cohorts provide general guidance for safe recipient/donor selection, but they must be tailored based on non-/partially-modifiable local circumstances to expand DCD utilization.

NRF2 assessment in discarded liver allografts: A role in allograft function and salvage

Antioxidant defence mechanisms, such as the nuclear factor-erythroid 2-related-factor-2 (NRF2) axis, are integral to oxidative stress responses and ischemic injury. Hepatic antioxidant capacity is contingent on parenchymal quality, and there is a need to develop new insights into key molecular mechanisms in marginal liver allografts that might provide therapeutic targets. This study examines the clinical relevance of NRF2 in donor livers and its response to normothermic machine perfusion (NMP). Discarded donor livers (n = 40) were stratified into a high NRF2 and low NRF2 group by quantifying NRF2 expression. High NRF2 livers had significantly lower transaminase levels, hepatic vascular inflammation and peri-portal CD3⁺ T cell infiltration. Human liver allografts (n = 8) were then exposed to 6-h of NMP and high NRF2 livers had significantly reduced liver enzyme alterations and improved lactate clearance. To investigate these findings further, we used a rat fatty-liver model, treating livers with an NRF2 agonist during NMP. Treated livers had increased NRF2 expression and reduced transaminase derangements following NMP compared to vehicle control. These results support the association of elevated NRF2 expression with improved liver function. Targeting this axis could have a rationale in future studies and NRF2 agonists may represent a supplemental treatment strategy for rescuing marginal donor livers.

Primary Nonfunction of the Liver Allograft

Severe allograft dysfunction, as opposed to the expected immediate function, following liver transplantation is a major complication, and the clinical manifestations of such that lead to either immediate retransplant or death are the catastrophic end of the spectrum. Primary nonfunction (PNF) has declined in incidence over the years, yet the impact on patient and healthcare teams, and the burden on the organ pool in case of the need for retransplant should not be underestimated. There is no universal test to define the diagnosis of PNF, and current criteria are based on various biochemical parameters surrogate of liver function; moreover, a disparity remains within different healthcare systems on selecting candidates eligible for urgent retransplantation. The impact on PNF from traditionally accepted risk factors has changed somewhat, mainly driven by the rising demand for organs, combined with the concerted approach by clinicians on the in-depth understanding of PNF, optimal graft recipient selection, mitigation of the clinical environment in which a marginal graft is reperfused, and postoperative management. Regardless of the mode, available data suggest machine perfusion strategies help reduce the incidence further but do not completely avert the risk of PNF. The mainstay of management relies on identifying severe allograft dysfunction at a very early stage and aggressive management, while excluding other identifiable causes that mimic severe organ dysfunction. This approach may help salvage some grafts by preventing total graft failure and also maintaining a patient in an optimal physiological state if retransplantation is considered the ultimate patient salvage strategy.

Safely Expanding the Liver Donor Pool by Utilization of Organs from Donation after Circulatory Death with Comparable Results to Donation After Brain Death, a Large Single-Center Experience

BACKGROUND

Use of livers donated after circulatory death (DCD) is one way to expand the donor pool. Our center has aggressively incorporated use of DCD liver grafts into practice. We examined our center and national outcomes as well as national DCD liver utilization.

METHODS

Liver transplants performed at our center and nationally from 11/2016 through 9/2020 were compared. Primary outcomes were patient and graft survival, and national DCD liver utilization.

RESULTS

For our center, DCD and donation after brain death (DBD) donors were similar except DCD donors were younger (37 vs 40 years; p < 0.05). Recipient Na-MELD (20 vs 24; p < 0.0001) and cold ischemia time (4.63 vs 5.18 h; p < 0.05) were lower in DCD recipients. There were no significant differences in 1-year patient and graft survival between DCD and DBD liver recipients locally. Nationally, there was a difference in 1-year graft survival year (89.4% vs 92.4%, p < 0.0001) but patient survival was similar between groups. The proportion of DCD livers recovered and transplanted widely varied among organ procurement organizations (OPOs) and transplant centers.

CONCLUSIONS

Similar outcomes for DCD and DBD liver recipients should encourage centers and OPOs nationwide to expand utilization of DCD livers.

Organ Donation after Circulatory Determination of Death in India: A Joint Position Paper

Organ donation following circulatory determination of death (DCDD) has contributed significantly to the donor pool in several countries. In India, majority of deceased donations happen following brain death (BD). While existing legislation allows for DCDD, there have been only few reports of kidney transplantation following DCDD from India. This document, prepared by a multidisciplinary group of experts, reviews international best practices in DCDD and outlines the path for DCDD in India. Ethical, medical, legal, economic, procedural, and logistic challenges unique to India have been addressed. The practice of withdrawal of life-sustaining treatment (WLST) in India, laid down by the Supreme Court of India, is time-consuming, possible only in patients in a permanent vegetative state, and too cumbersome for day-to-day practice. In patients where continued medical care is futile, the procedure for WLST is described. In controlled DCDD (category-III), decision for WLST is independent of and delinked from the subsequent possibility of organ donation. Families that are inclined toward organ donation are explained the procedure including the timing and location of WLST, consent for antemortem measures, no-touch period, and the possibility of stand-down and return to the intensive care unit (ICU) without donation. In donation following neurologic determination of death (DNDD), if cardiac arrest occurs during the process of BD declaration, the protocol for DCDD category-IV has been described in detail. In DCDD category-V, organ donation may be possible following unsuccessful cardiopulmonary resuscitation of cardiac arrest in the ICU. An outline of organ-specific requisites for kidney, liver, heart, and lung transplantation following DCDD and techniques, such as normothermic regional perfusion (nRP) and ex vivo machine perfusion, has been provided. The outcomes of transplantation following DCDD are comparable to those following DBDD or living donor transplantation. Documents and checklists necessary for successful execution of DCDD in India are described.

HOW TO CITE THIS ARTICLE

Seth AK, Mohanka R, Navin S, Gokhale AGK, Sharma A, Kumar A, et al. Organ Donation after Circulatory Determination of Death in India: A Joint Position Paper. Indian J Crit Care Med 2022;26(4):421-438.

Applicability of the UK DCD Risk Score in the modern era of liver transplantation: a U.S. update

Careful graft and recipient selection have resulted in improved outcomes in liver transplantation (LT) using donation after cardiac death (DCD) organs. The UK DCD Risk Score was established as a risk stratification tool to guide selection. We evaluated the applicability of the UK DCD Risk Score in a contemporary US cohort of adult DCD LT recipients using the United Network for Organ Sharing registry (2011-2020). 3,899 DCD LTs were included in our study (UK DCD Risk Score 0-5 points: 1,438 [36.9%], 6-9 points: 1,920 [49.2%]; 10-20 points: 541 [13.9%]). Compared to a score of 6-9 points, a score of 0-5 points was associated with decreased risk of graft loss (HR = 0.80, 95%CI: 0.68-0.94, P = 0.006), while a score of 10-20 points was associated with increased risk of graft loss (HR = 1.23, 95%CI: 1.01-1.51, P = 0.04). The 5-year graft survival for patients with risk scores of 0-5, 6-9, and 10-20 were 75.9%, 71.7%, and 67.9%, respectively. The C-statistic for the UK DCD Risk Score in our contemporary cohort was 0.611. The UK DCD Risk Score demonstrates a more limited ability to differentiate recipient outcomes in the modern era of DCD LT in the US. Acceptable long-term outcomes are achievable for patients stratified to the highest-risk group. This article is protected by copyright. All rights reserved.

Disposal of donor livers in Brazil: how to optimize their utilization rate in transplants?

OBJECTIVE

To understand the professionals´ perception of the use of deceased donor liver for transplantation, the reasons to decline them, and propose strategies to increase their use safely.

METHODS

This is a cross-sectional, descriptive qualitative-quantitative study. Professionals working with liver transplantation answered a self-administered, structured, and electronic questionnaire comprising 17 questions distributed into four sessions (demographic factors, perception of use of organs, reasons for disposal, and measures to favor their usage).

RESULTS

A total of 42 professionals participated in the study. The rate of use of organs was considered low by 71.43% (n=30) of respondents or very low by 19.05% (n=8). Everyone agreed that it was possible to increase it. Thirty-one (73.81%) participants believed the expansion of the population of extended criteria donors affected this index negatively. Donor-related conditions were the most frequent category of reasons for refusing a liver for transplantation, being the findings during organ retrieval the most frequent reason in clinical practice. Enhanced training of intensive care teams in the treatment of donors was the primary measure selected to favor the use of the organs, followed by investment in new technologies to optimize its preservation/evaluate its function before transplantation.

CONCLUSION

Implementation of strategies to increase the rate of acceptance of livers is expected. Improvements in donor intensive care and implementation of new preservation technologies should favor the use of the organs.

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.

Impact of the duration of normothermic regional perfusion on the results of liver transplant from controlled circulatory death donors: A retrospective, multicentric study

In France, the program of controlled donation after circulatory death (cDCD) was established with routine use of in situ normothermic regional perfusion (NRP). There is currently no consensus on its optimal duration. The purpose was to assess the impact of NRP duration on liver graft function and biliary outcomes. One-hundred and fifty-six liver recipients from NRP-cDCD donors from six French centers between 2015 and 2019 were included. Primary endpoint was graft function assessed by early allograft dysfunction (EAD, according to Olthoff's criteria) and MEAF (model for early allograft function) score. Overall, three (1.9%) patients had primary non-function, 30 (19.2%) patients experienced EAD, and MEAF score was 7.3 (±1.7). Mean NRP duration was 179 (±43) min. There was no impact of NRP duration on EAD (170±44 min in patients with EAD vs. 181±42 min in patients without, P = .286). There was no significant association between NRP duration and MEAF score (P = .347). NRP duration did neither impact on overall biliary complications nor on non-anastomotic biliary strictures (overall rates of 16.7% and 3.9%, respectively). In conclusion, duration of NRP in cDCD donors does not seem to impact liver graft function and biliary outcomes after liver transplantation. A 1 to 4-h perfusion represents an optimal time window.

Outcomes after simultaneous pancreas-kidney transplantation from donation after circulatory death donors: A UK registry analysis

There are concerns that simultaneous pancreas-kidney (SPK) transplants from donation after circulatory death (DCD) donors have a higher risk of graft failure than those from donation after brain death (DBD) donors. A UK registry analysis of SPK transplants between 2005 and 2018 was performed. Pancreas survivals of those receiving organs from DCD or DBD donors were compared. Multivariable analyses were used to adjust for baseline differences between the two groups and to identify factors associated with pancreas graft loss. A total of 2228 SPK transplants were implanted; 403 (18.1%) were from DCD donors. DCD donors were generally younger, slimmer, less likely to have stroke as a cause of death, with lower terminal creatinines and shorter pancreas cold ischemic times than DBD donors. Median (IQR) follow-up was 4.2 (1.6-8.1) years. On univariable analysis, there were no statistically significant differences in 5-year death-censored pancreas graft survival between the two donor types (79.5% versus 80.4%; p = .86). Multivariable analysis showed no statistically significant differences in 5-year pancreas graft loss between transplants from DCD (n = 343) and DBD (n = 1492) donors (hazard ratio 1.26, 95% CI 0.76-1.23; p = .12). The findings from this study support the increased use of SPK transplants from DCD donors.

Assessment of Donor Liver Pathology Predicts Survival After Liver Transplantation: A Retrospective Cohort Study

BACKGROUND

The aims of this study were to investigate the pathologic manifestation of pretransplant biopsy and to provide an accurate assessment method for liver graft of China Donation after Citizen's Death (CDCD).

METHODS

A retrospective analysis was performed based on clinical and biopsy data of 96 CDCD liver transplantations completed between January 2012 and December 2017. The pretransplant pathologic sections were semiquantitatively scored according to Banff Schema recommendations on liver allograft pathology. Graft overall survival (OS) and early allograft dysfunction (EAD) rates were observed.

RESULTS

The histologic analysis of the 96 CDCD liver graft biopsy specimens was summarized, including portal area neutrophilic infiltrate, macrovesicular steatosis, microvesicular steatosis, and hepatocellular swelling. Among these pathologic characteristics, only portal area neutrophilic infiltrate ≥20% was an independent risk factor for graft survival, although it has limited effect on the recipient's short-term prognosis.

CONCLUSIONS

We found that portal area neutrophilic infiltrate ≥20% was an independent risk factors for long-term graft survival. According to this criterion, we can identify liver transplant recipients at risk for poor prognosis and make timely interventions.