Donation After Cardiac Death in Liver Transplantation: An Additional Source of Organs With Similar Results to Donation After Brain Death

Does Time to Asystole in Donors After Circulatory Death Impact Recipient Outcome in Liver Transplantation?

BACKGROUND

The agonal phase can vary following treatment withdrawal in donor after circulatory death (DCD). There is little evidence to support when procurement teams should stand down in relation to donor time to death (TTD). We assessed what impact TTD had on outcomes following DCD liver transplantation.

METHODS

Data were extracted from the UK Transplant Registry on DCD liver transplant recipients from 2006 to 2021. TTD was the time from withdrawal of life-sustaining treatment to asystole, and functional warm ischemia time was the time from donor systolic blood pressure and/or oxygen saturation falling below 50 mm Hg and 70%, respectively, to aortic perfusion. The primary endpoint was 1-y graft survival. Potential predictors were fitted into Cox proportional hazards models. Adjusted restricted cubic spline models were generated to further delineate the relationship between TTD and outcome.

RESULTS

One thousand five hundred fifty-eight recipients of a DCD liver graft were included. Median TTD in the entire cohort was 13 min (interquartile range, 9-17 min). Restricted cubic splines revealed that the risk of graft loss was significantly greater when TTD ≤14 min. After 14 min, there was no impact on graft loss. Prolonged hepatectomy time was significantly associated with graft loss (hazard ratio, 1.87; 95% confidence interval, 1.23-2.83; P = 0.003); however, functional warm ischemia time had no impact (hazard ratio, 1.00; 95% confidence interval, 0.44-2.27; P > 0.9).

CONCLUSIONS

A very short TTD was associated with increased risk of graft loss, possibly because of such donors being more unstable and/or experiencing brain stem death as well as circulatory death. Expanding the stand down times may increase the utilization of donor livers without significantly impairing graft outcome.

Bioenergetic and Cytokine Profiling May Help to Rescue More DCD Livers for Transplantation

The majority of organs used for liver transplantation come from brain-dead donors (DBD). In order to overcome the organ shortage, increasingly donation after circulatory death (DCD) organs are also considered. Since normothermic machine perfusion (NMP) restores metabolic activity and allows for in-depth assessment of organ quality and function prior to transplantation, such organs may benefit from NMP. We herein compare the bioenergetic performance through a comprehensive evaluation of mitochondria by high-resolution respirometry in tissue biopsies and the inflammatory response in DBD and DCD livers during NMP. While livers were indistinguishable by perfusate biomarker assessment and histology, our findings revealed a greater impairment of mitochondrial function in DCD livers after static cold storage compared to DBD livers. During subsequent NMPs, DCD organs recovered and eventually showed a similar performance as DBD livers. Cytokine expression analysis showed no differences in the early phase of NMP, while towards the end of NMP, significantly elevated levels of IL-1β, IL-5 and IL-6 were found in the perfusate of DCD livers. Based on our results, we find it worthwhile to reconsider more DCD organs for transplantation to further extend the donor pool. Therefore, donor organ quality criteria must be developed, which may include an assessment of bioenergetic function and cytokine quantification.

Good post-transplant outcomes using liver donors after circulatory death when applying strict selection criteria: A propensity-score matched-cohort study

INTRODUCTION AND OBJECTIVES

Outcomes of liver transplantation (LT) with donors after circulatory death (DCD) have been considered suboptimal due to higher rates of ischemic cholangiopathy, especially when the super-rapid recovery (SRR) technique is used. This study aimed to compare the incidence of complications between recipients receiving DCD vs those receiving donors after brain death (DBD) in a large-volume liver transplant centre.

METHODS

We performed a retrospective cohort study (LT from January 2015 to December 2018) comparing recipients who underwent a LT with DCD vs. a control group of LT with DBD, matched 1:1 without replacement by propensity score matching that included the following variables: LT indication, recipient sex and age, donor age and MELD score.

RESULTS

51 recipients with DCD-LT (29 SRR, 22 normothermic regional perfusion [NRP]) were matched with 51 DBD-LT recipients. Biliary complications were more frequent in DCD, 10% (n=5), all with SRR technique, vs 2% (n=1) in the DBD group, p=0.2. Two patients (4%) suffered primary graft non-function in the DCD group (1 SRR and 1 NRP) versus zero in the DBD group (p=0.49). Postoperative bleeding and reinterventions were also higher in the DCD group: 7 (13.7%) vs 1 (1.95%) and 8 (15.7%) vs 2 (3.9%) respectively (p=0.06 and 0.09). On the 1^st postoperative day AST/ALT peak was higher in DCD (p≤0001). The incidence of rejection, vascular complications, renal injury, hospital stay, and readmissions were similar in both groups. Cumulative 1-, 2-, 3- and 4-year graft and patient survival were also similar.

CONCLUSIONS

DCD donors are an adequate option to increase the donor pool in LT, achieving similar graft and patient survival rates to those achieved with DBD donors, especially when the NRP technique is used.

Temporal Trends in Utilization and Outcomes of DCD Livers in the United States

BACKGROUND

Historically, donation after circulatory death (DCD) livers were frequently discarded because of higher mortality and graft loss after liver transplantation (LT). However, the demand for LT continues to outstrip the supply of "acceptable" organs. Additionally, changes in the donor pool, organ allocation, and clinical management of donors and recipients, and improved clinical protocols might have altered post-DCD-LT outcomes.

METHODS

We studied 5975 recovered DCD livers using US Scientific Registry of Transplant Recipients data from 2005 to 2017, with a comparison group of 78 235 adult donation after brain death (DBD) livers recovered during the same time period. We quantified temporal trends in discard using adjusted multilevel logistic regression and temporal trends in post-LT mortality and graft loss for DCD LT recipients using adjusted Cox regression.

RESULTS

DCD livers were more likely to be discarded than DBD livers across the entire study period, and the relative likelihood of discard increased over time (adjusted odds ratio [aOR] of discard DCD versus DBD 3.854.455.14 2005-2007, 5.225.876.59 2015-2017) despite improving outcomes after DCD LT. Mortality risk for DCD LTs decreased in each time period (compared with 2005-2007, aHR 2008-2011 0.720.840.97, aHR 2012-2014 0.480.580.70, aHR 2015-2017 0.340.430.55), as did risk of graft loss (compared with 2005-2007, aHR 2008-2011 0.690.810.94, aHR 2012-2014 0.450.550.67, aHR 2015-2017 0.360.450.56).

CONCLUSIONS

Despite dramatic improvements in outcomes of DCD LT recipients, DCD livers remain substantially more likely to be discarded than DBD livers, and this discrepancy has actually increased over time. DCD livers are underutilized and have the potential to expand the donor pool.

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.

Outcome of Liver Transplants Using Donors After Cardiac Death With Normothermic Regional Perfusion

BACKGROUND AND AIMS

The incorporation of normothermic regional perfusion (NRP) to donors after cardiac death (DCD) allows the recovery of liver grafts without the deleterious effects on graft survival the super-rapid technique may cause. The aim of the present report is to determine if the use of NRP in Maastricht type III DCD donors achieves short- and medium-term results comparable to donors after brain death (DBD).

PATIENTS AND METHODS

This is an observational cohort study including 117 liver transplants executed between November 2016 and April 2021, divided into NRP (n = 39) and DBD (n = 78).

RESULTS

Donors were younger in the NRP group (NRP 52 vs DBD 59.4 years; P < .005). Liver recipients in each study group were of similar age and severity of liver disease, although the predominant transplant indication in the NRP group was hepatocellular carcinoma. No differences in ischemia times were found. The incidence of early allograft disfunction and primary nonfunction was balanced between NRP and DBD. Eight patients required retransplant, all of them in the DBD group. No differences were found in biliary complications (NRP 12% vs DBD 5%; P = .104). Ischemic cholangiopathy affected a single DBD patient. Graft survival's Kaplan Meier curve shows a better outcome in the NRP group, although the difference did not reach significance (P = .075).

CONCLUSIONS

The incorporation of perfusion machines, and specifically the NPR in situ, converts suboptimal liver grafts such as DCD into organs comparable to DBDs.

Liver transplant after donation from controlled circulatory death versus brain death: A UNOS database analysis and publication bias adjusted meta-analysis

BACKGROUND

Donation after circulatory death (DCD) is an increasingly utilized alternative to donation after brain death (DBD) to expand the liver donor pool. We compared the outcomes of liver transplant (LT) after DCD versus DBD.

METHODS

A PRISMA-compliant systematic literature review was performed using the PubMed, Cochrane Library, and Embase databases (end-of-search-date: July 2, 2020). US outcomes were analyzed using the UNOS database (February, 2002-September, 2020). Pooled hazard ratios (HR) for patient and graft survival were obtained through random effect meta-analyses and adjusted for publication bias.

RESULTS

Thirteen studies reporting on 1426 DCD and 5385 DBD LT recipients were included. 5620 DCD and 87561 DBD LT recipients were analyzed from the UNOS database. Meta-analysis showed increased risk of patient mortality for DCD (HR = 1.36; 95%CI, 1.09-1.70; P = .01; I²  = 53.6%). When adjusted for publication bias, meta-analysis showed no difference in patient survival between DCD and DBD (HR = 1.15; 95%CI, .91-1.45; P = .25; I²  = 61.5%). Meta-analysis showed increased risk of graft loss for DCD (HR = 1.50; 95%CI, 1.20-1.88; P < .001; I²  = 67.8%). When adjusted for publication bias, meta-analysis showed a reduction in effect size (HR = 1.36; 95%CI, 1.06-1.74; P = .02; I²  = 73.5%).

CONCLUSION

When adjusted for publication bias, no difference was identified between DCD and DBD regarding patient survival, while DCD was associated with an increased risk of graft loss.

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

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

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.

Donation After Circulatory Death Yields Survival Rates Similar to Donation After Brain Death Liver Transplant, Which Effectively Expands the Donor Pool

OBJECTIVES

Liver allograft shortage has necessitated greater use of donations after circulatory death. Limited data are available to compare recipients' health care utilization for donation after circulatory death versus brain death.

MATERIALS AND METHODS

Liver transplant data for our center from November 2016 until May 2019 were obtained (208 donations after brain death and 39 after circulatory death). We excluded patients <18 years old and multiorgan transplants; for cost data only, we also excluded retransplants. Primary outcome was recipients' health care utilization in donation after circulatory death versus brain death and included index admission length of stay, readmissions, and charges from transplant to 6 months. Secondary outcomes were patient and graft survival.

RESULTS

Donors from circulatory death were younger than donors from brain death (median age 32 vs 40 years; P < .01). Recipient body mass index (31.23 vs 29.38 kg/m2), Model for End-Stage Liver Disease score (17 vs 19), portal vein thrombosis (15.8% vs 18.0%), length of stay (7 vs 8 days), and 30-, 90-, and 180-day posttransplant index admissions were not significantly different. Charges for index admission were equivalent for donation after circulatory death ($370771) and brain death ($374272) (P = .01). Charges for readmissions at 30 and 180 days were not significantly different (P = .80 and P = .19, respectively). Rates for graft failure (10.3% vs 4.8%; P = .08) and recipient death (10.3% vs 3.8%; P = .17) at 6 months posttransplant were similar.

CONCLUSIONS

Donation after circulatory death versus brain death liver transplant recipients had similar lengths of stay and equivalent index admission charges. Graft and patient survival and charges from transplant to 6 months were similar. Donation after circulatory death liver allografts provide a safe, costequivalent donor pool expansion after careful donorrecipient selection.

A 'real-world' analysis of risk factors for post liver transplant delirium and the effect on length of stay

BACKGROUND

The development of delirium has been previously demonstrated to be associated with an increased risk of mortality and length of stay post liver transplant (LTx) with multiple risk factors being identified in previous studies. In this study, we have aimed to identify the most important variables associated with the onset of post-LTx delirium and understand the effect on length of stay (LOS).

METHODS

All liver transplants for chronic liver disease between 1 August 2012 and 1 August 2017 were included (n = 793). Data were collected for analysis retrospectively from electronic patient records.

RESULTS

Delirium is associated with an overall increased hospital and ICU LOS but not one-year mortality. The risk of developing post-LTx delirium was the greatest among patients: with post-LTx sepsis, who required renal sparing immunosuppression, who received donation after cardiac death (DCD) grafts and who were older. Patients with autoimmune hepatitis, primary biliary cholangitis or primary sclerosing cholangitis seemed to be at lower risk of post-LTx delirium. However, global patient LOS was only prolonged in patients with sepsis and renal failure.

CONCLUSION

Many of the risk factors previously described to be associated with the development of post-LTx delirium were not demonstrated to be significant in this study. Sepsis, renal failure, older age and DCD use are associated with delirium post-LTx. It is unclear if this syndrome is an independent risk factor for increased LOS or if it is a symptom of well established syndromes associated with increased LOS. The role for prophylactic strategies to reduce the incidence of post-LTx delirium is therefore unclear.

Biliary complications in donation after circulatory death liver transplantation: the Australian National Liver Transplantation Unit's experience

BACKGROUND

Biliary complications are the most common complications of donation after circulatory death (DCD) liver transplantation and the international experience with DCD transplants suggests increased rates of biliary complications compared to donation after brain death transplants. Therefore, it is important to understand factors that are associated with the development of biliary complications within the Australian DCD context in order to inform future practice. The aim of this study is to determine the incidence of biliary complications after DCD liver transplantation at the Australian National Liver Transplantation Unit and identify factors associated with this outcome.

METHODS

A retrospective analysis of all adult DCD liver transplants at the Australian National Liver Transplantation Unit from 2007 to 2015 was undertaken. The primary outcome measure was the incidence of biliary complications and was censored on 31 December 2016. Recipients were then stratified into groups based on the development of biliary complications and risk factor analysis was performed.

RESULTS

Biliary complications occurred in 35% of DCD transplants, including seven anastomotic strictures and 10 non-anastomotic strictures. Higher donor risk index scores (P = 0.03), post-transplant portal vein complications (P = 0.042) and peak gamma-glutamyl transferase levels within 7 days post-transplant (P = 0.047) were associated with biliary complications.

CONCLUSION

Findings from this study demonstrate that biliary complications remain common in DCD liver recipients. Recipients who developed a biliary complication tended to have higher donor risk index, elevated peak gamma-glutamyl transferase levels within 7 days post-transplant or a portal vein complication. The presence of any of these factors should prompt close monitoring for post-transplant biliary complications.

Microsteatosis in Livers From Donation After Circulatory Death Donors Is Associated With Inferior Outcomes Following Liver Transplantation

The acceptable threshold remains unknown for the percentage of macrosteatosis (MaS) and microsteatosis (MiS) to yield optimal outcomes after donation after circulatory death (DCD) liver transplantation (LT). The purpose of this analysis was to determine the impact of donor liver MaS and MiS on DCD LT outcomes. Using the Organ Procurement and Transplantation Network database, we analyzed pretransplant biopsy results from adult, solitary, DCD livers transplanted between January 1, 2006, and December 31, 2017. Kaplan-Meier analysis was used to assess graft and patient survival based on MaS and MiS severity. MiS was divided into the groups MiS ≤10% and >10%. MaS was divided into the groups MaS ≤15% and >15%. Of 7757 recovered DCD livers, 11.4% (n = 885) were biopsied and transplanted. Patients who received DCD livers with MaS >15% had significantly worse patient survival (P < 0.04), and those with MiS >10% demonstrated inferior graft and patient survival (P < 0.02). In multivariate analyses including known risk factors, both MaS >15% and MiS >10% were associated with increased risk of graft failure and patient mortality (P < 0.03). Recipient and donor age >60 years were also associated with increased risk of graft failure and patient death. This analysis demonstrates that MaS >15% and MiS >10% are additional risk factors for graft loss and patient mortality in DCD LT.

The Human Immune Response to Cadaveric and Living Donor Liver Allografts

The liver is an important contributor to the human immune system and it plays a pivotal role in the creation of both immunoreactive and tolerogenic conditions. Liver transplantation provides the best chance of survival for both children and adults with liver failure or cancer. With current demand exceeding the number of transplantable livers from donors following brain death, improved knowledge, technical advances and the desire to prevent avoidable deaths has led to the transplantation of organs from living, ABO incompatible (ABOi), cardiac death donors and machine based organ preservation with acceptable results. The liver graft is the most well-tolerated, from an immunological perspective, of all solid organ transplants. Evidence suggests successful cessation of immunosuppression is possible in ~20–40% of liver transplant recipients without immune mediated graft injury, a state known as “operational tolerance.” An immunosuppression free future following liver transplantation is an ambitious but perhaps not unachievable goal. The initial immune response following transplantation is a sterile inflammatory process mediated by the innate system and the mechanisms relate to the preservation-reperfusion process. The severity of this injury is influenced by graft factors and can have significant consequences. There are minimal experimental studies that delineate the differences in the adaptive immune response to the various forms of liver allograft. Apart from ABOi transplants, antibody mediated hyperacute rejection is rare following liver transplant. T-cell mediated rejection is common following liver transplantation and its incidence does not differ between living or deceased donor grafts. Transplantation in the first year of life results in a higher rate of operational tolerance, possibly due to a bias toward Th2 cytokines (IL4, IL10) during this period. This review further describes the current understanding of the immunological response toward liver allografts and highlight the areas of this topic yet to be fully understood.

Does Normothermic Regional Perfusion Improve the Results of Donation After Circulatory Death Liver Transplantation?

BACKGROUND

The so-called grafts or donors with extended criteria are a risk factor for the development of liver transplant activity. One source comes from controlled donation after circulatory death (cDCD). The hypothesis was to verify the improvement in results by comparing DCD liver transplants performed with postmortem normothermic regional perfusion (NRP) vs super-rapid recovery (SRR), the current standard for cDCD. A prospective study comparing both techniques was carried out.

METHODS

A total of 42 transplants were performed with cDCD, 22 of which were with SRR and 23 with NRP from April 2014 to September 2019.

RESULTS

Differences were found in early allograft dysfunction (68.1% in the SRR group vs 25% in the NRP group; P < .01) and biliary complications (22.7% vs 5%, respectively; P = .04). Differences were also found, although not statistically significant, in ischemic cholangiopathy (13.6% in the SRR group vs 5% in the NRP group; P = .09), and retransplant rate (9.1% vs 0%, respectively; P = .3).

CONCLUSIONS

With the use of NRP machines, results are similar to the standard donation with donors in brain death in terms of rate of early allograft dysfunction and survival of the patient and graft attempted, reducing the rate of ischemic cholangiopathy compared with SRR.

Donors After Circulatory Death: Theme of Present or a Future? The Research in West Poland

The most urgent issue in transplantology nowadays is to increase the number of donors as replacement of lungs, heart, and liver in end-stage disease remains the only available method to save patients. Donors after brain death (DBD), these after irreversible cessation of brain function, represent 95% of all donors. On the contrary, donors after circulatory death (DCD), namely donors after irreversible detention of circulation, a group of great potential, is totally unused. The survey was done among 500 people from the medical staff of the intensive care unit and intensive cardiological care where the probability of receiving anonymous donation after circulatory death is the highest, yet only 368 people had completed the survey and their cases were taken into consideration as far as the study was concerned. The survey was conducted in the form of a self-projected questionnaire based on the Hospital Attitude Survey. The study showed that 98.4% of respondents accept the transplant. As many as 93.1% of people did not know the Maastricht classification, and 57.5% claimed that in Poland there is permission to take organs from people with a nonbeating heart. Ninety percent of respondents expressed their willingness to participate in training, and 70% of them were interested in the subject of the training presented in the questionnaire. At a time of such immense need for organs and such a huge disparity in the number of donors and recipients, DCD type of transplantation may be an alternative for patients whose waiting time for donation from a DBD would total a few years.