Intraoperative Events in Liver Transplantation Using Donation After Circulatory Death Donors

Management of the liver transplant candidate with high cardiac risk: Multidisciplinary best practices and recommendations

In a setting characterized by a growing prevalence of patients with alcohol-associated and metabolic dysfunction-associated steatotic liver diseases, coupled with an aging patient demographic, the incidence of cardiac comorbidities in liver transplant candidates is on the rise. These comorbidities not only pose barriers to transplant eligibility but also impact the intraoperative course and affect posttransplant outcomes. As such, there is a significant need to optimize the clinical management of these cardiac comorbidities. However, there is a scarcity of evidence regarding the best practices for managing cardiac comorbidities such as coronary and valvular heart diseases, arrhythmia, and cardiomyopathy in this population, both before and during transplant surgery. These conditions necessitate a coordinated and multidisciplinary approach to care. In this manuscript, we conduct a comprehensive review of the most recent evidence pertaining to the preoperative and intraoperative management of these cardiac comorbidities in liver transplant candidates. Our aim is to provide recommendations that improve and standardize their clinical care.

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

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

Development of a portable abdominal normothermic regional perfusion (A-NRP) program in the United States

In situ abdominal normothermic regional perfusion (A-NRP) has been used for liver transplantation (LT) with donation after circulatory death (DCD) liver grafts in Europe with excellent results; however, adoption of A-NRP in the United States has been lacking. The current report describes the implementation and results of a portable, self-reliant A-NRP program in the United States. Isolated abdominal in situ perfusion with an extracorporeal circuit was achieved through cannulation in the abdomen or femoral vessels and inflation of a supraceliac aortic balloon and cross-clamp. The Quantum Transport System by Spectrum was used. The decision to use livers for LT was made through an assessment of perfusate lactate (q15min). From May to November 2022, 14 A-NRP donation after circulatory death procurements were performed by our abdominal transplant team (N = 11 LT, N = 20 kidney transplants, and 1 kidney-pancreas transplant). The median A-NRP run time was 68 minutes. None of the LT recipients had post-reperfusion syndrome, nor were there any cases of primary nonfunction. All livers were functioning well at the time of maximal follow-up with zero cases of ischemic cholangiopathy. The current report describes the feasibility of a portable A-NRP program that can be used in the United States. Excellent short-term post-transplant results were achieved with both livers and kidneys procured from A-NRP.

Introducing Machine Perfusion into Routine Clinical Practice for Liver Transplantation in the United States: The Moment Has Finally Come

While adoption of machine perfusion technologies into clinical practice in the United States has been much slower than in Europe, recent changes in the transplant landscape as well as device availability following FDA approval have paved the way for rapid growth. Machine perfusion may provide one mechanism to maximize the utilization of potential donor liver grafts. Indeed, multiple studies have shown increased organ utilization with the implementation of technologies such as ex-situ normothermic machine perfusion (NMP), ex-situ hypothermic machine perfusion (HMP) and in-situ normothermic regional perfusion (NRP). The current review describes the history and development of machine perfusion utilization in the Unites States along with future directions. It also describes the differences in landscape between Europe and the United States and how this has shaped clinical application of these technologies.

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.

Elevated effluent potassium concentrations predict the development of postreperfusion hyperkalemia in deceased liver transplantation: a retrospective cohort study

BACKGROUND

Postreperfusion hyperkalemia (PRHK) has garnered increasing attention in regard to deceased liver transplantation (LT), especially for LT using the expanded criteria donor grafts. However, the impact of the effluent potassium (eK⁺) concentration on PRHK has been largely overlooked. We evaluated whether elevated eK⁺ concentrations are associated with PRHK in deceased LT.

METHODS

In this single-institution, retrospective cohort study, we included all adults who underwent deceased LT with intraoperative eK⁺ concentration monitoring between November 2016 and December 2018. The eK⁺ concentrations were obtained from the effluent samples collected following a standard portal vein flush. PRHK was defined as any serum potassium (sK⁺) level of > 5.5 mmol/L following reperfusion. Logistic regression was performed to identify predictors for PRHK, and linear regression was used to examine predictors of the maximum percentage increase in the sK⁺ level following reperfusion.

RESULTS

Of the 86 patients who met the inclusion criteria, 54 (62.8%) developed PRHK. Independent predictors for PRHK included greater graft weight (OR 1.283 [95% CI 1.029-1.599] per 100 g, P = 0.027), an elevated eK⁺ concentration (OR 1.291 [95% CI 1.068-1.561] per mol/L, P = 0.008), and a higher sK⁺ level before reperfusion (OR 4.459 [95% CI 1.543-12.884] per mol/L, P = 0.006). An eK⁺ concentration of more than 6.9 mmol/L had a sensitivity of 59.26% and a specificity of 78.12% for predicting PRHK (area under the receiver operating characteristic curve, 0.694). Multiple linear regression analyses indicated that the eK⁺ and sK⁺ levels before reperfusion were significant predictors of the maximum percentage increase in the sK⁺ level following reperfusion. In addition, PRHK was associated with an increased risk of postreperfusion significant arrhythmias, severe postreperfusion syndrome, and postoperative early allograft dysfunction.

CONCLUSIONS

This study shows that the eK⁺ concentration could predict the risk of PRHK in deceased LT. Further prospective studies are warranted to clarify these associations.

Controlled DCD Liver Transplantation Is Not Associated With Increased Hyperfibrinolysis and Blood Loss After Graft Reperfusion

BACKGROUND

The specific effect of donation after circulatory death (DCD) liver grafts on fibrinolysis, blood loss, and transfusion requirements after graft reperfusion is not well known. The aim of this study was to determine whether transplantation of controlled DCD livers is associated with an elevated risk of hyperfibrinolysis, increased blood loss, and higher transfusion requirements upon graft reperfusion, compared with livers donated after brain death (DBD).

METHODS

A retrospective single-center analysis of all adult recipients of primary liver transplantation between 2000 and 2019 was performed (total cohort n = 628). Propensity score matching was used to balance baseline characteristics for DCD and DBD liver recipients (propensity score matching cohort n = 218). Intraoperative and postoperative hemostatic variables between DCD and DBD liver recipients were subsequently compared. Additionally, in vitro plasma analyses were performed to compare the intraoperative fibrinolytic state upon reperfusion.

RESULTS

No significant differences in median (interquartile range) postreperfusion blood loss (1.2 L [0.5-2.2] versus 1.3 L [0.6-2.2]; P = 0.62), red blood cell transfusion (2 units [0-4] versus 1.1 units [0-3]; P = 0.21), or fresh frozen plasma transfusion requirements (0 unit [0-2.2] versus 0 unit [0-0.9]; P = 0.11) were seen in DCD compared with DBD recipients, respectively. Furthermore, plasma fibrinolytic potential was similar in both groups.

CONCLUSIONS

Transplantation of controlled DCD liver grafts does not result in higher intraoperative blood loss or more transfusion requirements, compared with DBD liver transplantation. In accordance with this, no evidence for increased hyperfibrinolysis upon reperfusion in DCD compared with DBD liver grafts was found.

Liver transplant with controlled donors after circulatory death with normothermic regional perfusion and brain dead donors: A multicenter cohort study of transfusion, one-year graft survival and mortality

BACKGROUND

Controlled donation after circulatory death (cDCD) has expanded the donor pool for liver transplantation (LT). However, transfusion requirements and perioperative outcomes should be elucidated. The aim of this multicenter study was to assess red blood cell (RBC) transfusions, one-year graft and patient survival after LT after cDCD with normothermic regional perfusion (NRP) compared with donors after brain death (DBD).

METHODS

591 LT carried out in ten centers during 2019 were reviewed. Thromboelastometry was used to manage coagulation and blood product transfusion in all centers. Normothermic regional perfusion was the standard technique for organ recovery.

RESULTS

447 patients received DBD and 144 cDCD with NRP. Baseline MCF Extem was lower in the cDCD group There were no differences in the percentage of patients (63% vs. 61% p = 0.69), nor in the number of RBC units transfused (4.7 (0.2) vs 5.5 (0.4) in DBD vs cDCD, p = 0.11. Twenty-six patients (6%) died during admission for LT in the DBD group compared with 3 patients (2%) in the cDCD group (p = 0.15). To overcome the bias due to a worse coagulation profile in cDCD recipients, matched samples were compared. No differences in baseline laboratory data, or in intraoperative use of RBC or one-year outcome data were observed between DBD and cDCD recipients.

CONCLUSIONS

cDCD with NRP is not associated with increased RBC transfusion. No differences in graft and patient survival between cDCD and DBD were found. Donors after controlled circulatory death with NRP can increasingly be utilized with safety, improving the imbalance between organ donors and the ever-growing demand.

Thromboelastography profiles for controlled circulatory death donors: Validating the role of heparin

Controlled donation after circulatory death (cDCD) liver transplants are associated with increased ischemic-type biliary complications. Microvascular thrombosis secondary to decreased donor fibrinolysis may contribute to bile duct injury. We hypothesized that cDCD donors are hypercoagulable with impaired fibrinolysis and aim to use thromboelastography to characterize cDCD coagulation profiles.

Donation after circulatory death liver transplantation: An in-depth analysis and propensity score-matched comparison

BACKGROUND

Careful donor-recipient matching and reduced ischemia times have improved outcomes following donation after circulatory death (DCD) liver transplantation (LT). This study examines a single-center experience with DCD LT including high-acuity and hospitalized recipients.

METHODS

DCD LT outcomes were compared to a propensity score-matched (PSM) donation after brain death (DBD) LT cohort (1:4); 32 DCD LT patients and 128 PSM DBD LT patients transplanted from 2008 to 2018 were included. Analyses included Kaplan-Meier estimates and Cox proportional hazards models examining patient and graft survival.

RESULTS

Median MELD score in the DCD LT cohort was 22, with median MELD of 27 for DCD LT recipients with decompensated cirrhosis. No difference in mortality or graft loss was found (p < .05) between DCD LT and PSM DBD LT at 3 years post-transplant, nor was DCD an independent risk factor for patient or graft survival. Post-LT severe acute kidney injury was similar in both groups. Ischemic-type biliary lesions (ITBL) occurred in 6.3% (n = 2) of DCD LT recipients, resulting in 1 graft loss and 1 death.

CONCLUSION

This study supports that DCD LT outcomes can be similar to DBD LT, with a low rate of ITBL, in a cohort including high-acuity recipients. Strict donor selection criteria, ischemia time minimization, and avoiding futile donor/recipient combinations are essential considerations.

Expanding Role of Donation After Circulatory Death Donors in Liver Transplantation

Better understanding of how to utilize donation after circulatory death (DCD) liver grafts has resulted in improved national outcomes and expansion in the number of DCD liver transplants (LTs). This improvement has been driven by better donor and recipient matching, careful evaluation of hemodynamics during withdrawal of life support, and refinement of the procurement operation. Changes to liver allocation likely will result in increased utilization of DCD liver grafts. Ischemic cholangiopathy remains the Achilles heel of DCD LTs and, although rates have fallen with improved protocols, a certain rate likely is unavoidable. This review discusses contemporary issues with DCD LTs.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

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

Comparative Anatomical Study Between the Human and Swine Liver and Its Importance in Xenotransplantation

The liver is a multifunctional organ; due to its functional and structural complexity, there are many factors that may lead it to function inadequately, a state called liver failure. Transplantation is the only appropriate therapy for patients in cases of liver failure. However, there are many limitations to this treatment, and the scientific community has considered methods based on pigs because of their unique structural and cellular compatibility with humans. In this review, we conducted an anatomic comparative study of the liver’s parenchyma and vascular network between humans and pigs to extract useful information for xenotransplantation and autologous cell or organ generation in pigs. We reviewed articles from 2007 to 2019 and used the databases of Scopus, PubMed and Google Scholar. We concluded that, despite the difference concerning the shape of the human and pig livers, the number of segments and the bile and vascular system are similar, making the pig liver useful in experimental surgery for xenotransplantation.

The Changing Landscapes in DCD Liver Transplantation

Purpose of Review

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

Recent Findings

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

Summary

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

2019 Clinical Update in Liver Transplantation

Liver transplantation continues be the standard for treatment of end-stage liver disease, and even with recent advances in organ preservation, the anesthetic management continues to require understanding of multiple organ systems beyond the liver. Multiple factors contribute to hemodynamic changes after reperfusion of the liver graft that anesthesiologists should be aware of before unclamping. Concomitant renal dysfunction in end-stage liver disease is not uncommon, and preparation for continuous renal replacement therapy may need to be considered in certain cases. Cardiac evaluation of liver transplantation patients with an emphasis on arrhythmias, including atrial fibrillation, can help prevent both intraoperative and postoperative complications detrimental to the patient and graft. Finally, combined liver and thoracic organ transplantations may be indicated for certain disease processes that affect multiple organs. These cases require an understanding of the surgical technique and acknowledgment that some goals of the procedures may be in direct opposition to each other.