Improved Early Post-Transplant Outcomes and Organ Use in Kidney Transplant Using Normothermic Regional Perfusion for Donation after Circulatory Death: National Experience in the US

Normothermic Machine Perfusion and Normothermic Regional Perfusion of DCD Kidneys Before Transplantation: A Systematic Review

BACKGROUND

To overcome organ shortages, donation after circulatory death (DCD) kidneys are being increasingly used for transplantation. Prior research suggests that DCD kidneys have inferior outcomes compared with kidneys donated after brain death. Normothermic machine perfusion (NMP) and normothermic regional perfusion (NRP) may enhance the preservation of DCD kidneys and improve transplant outcomes. This study aimed to review the evidence surrounding NMP and NRP in DCD kidney transplantation.

METHODS

Two independent reviewers conducted searches for all publications reporting outcomes for NMP and NRP-controlled DCD kidneys, focusing on delayed graft function, primary nonfunction, graft function, graft survival, and graft utilization. Weighted means were calculated for all relevant outcomes and controls. Formal meta-analyses could not be conducted because of significant heterogeneity.

RESULTS

Twenty studies were included for review (6 NMP studies and 14 NRP studies). Delayed graft function rates seemed to be lower for NRP kidneys (24.6%) compared with NMP kidneys (54.3%). Both modalities yielded similar outcomes with respect to primary nonfunction (NMP 3.3% and NRP 5.6%), graft function (12-mo creatinine 149.3 μmol/L for NMP and 129.9 μmol/L for NRP), and graft utilization (NMP 83.3% and NRP 89%). Although no direct comparisons exist, our evidence suggests that both modalities have good short- and medium-term graft outcomes and high graft survival rates.

CONCLUSIONS

Current literature demonstrates that both NMP and NRP are feasible strategies that may increase donor organ utilization while maintaining acceptable transplant outcomes and likely improved outcomes compared with cold-stored DCD kidneys. Further research is needed to directly compare NRP and NMP outcomes.

Challenges and opportunities in organ donation after circulatory death

In recent years, there has been resurgence in donation after circulatory death (DCD). Despite that, the number of organs transplanted from these donors remains low due to concerns about their function and a lack of an objective assessment at the time of donation. This overview examines the current DCD practices and the classification modifications to accommodate regional perspectives. Several risk factors underscore the reluctance to accept DCD organs, and we discuss the modern strategies to mitigate them. The advent of machine perfusion technology has revolutionized the field of DCD transplantation, leading to improved outcomes and better organ usage. With many strategies at our disposal, there is an urgent need for comparative trials to determine the optimal use of perfusion technologies for each donated organ type. Additional progress in defining therapeutic strategies to repair the damage sustained during the dying process should further improve DCD organ utilization and outcomes. However, there remains wide variability in access to DCD donation and transplantation, and organizational efforts should be doubled up with consensus on key ethical issues that still surround DCD donation in the era of machine perfusion.

A scoping review of the legal and ethical challenges with the use of normothermic regional perfusion in controlled donation after circulatory determination of death from 2005 to 2023

Use of normothermic regional perfusion (NRP) to enable organ reconditioning and assessment in donation after circulatory determination of death is controversial. We conducted a scoping review of peer-reviewed articles, news media, legal literature, and professional society position statements addressing ethical and/or legal issues in use of NRP in controlled donation after circulatory determination of death from January 1, 2005, to January 5, 2024. Thematic analysis, assessing the 4 principles of bioethics (autonomy, beneficence, nonmaleficence, and justice) and subthemes identified within each, was conducted for the 112 publications meeting inclusion criteria. More than 30 publications addressed the topic in each of 2022 and 2023, vs ≤6 per year previously. Nonmaleficence was the most frequently addressed bioethical principle (111/112 publications), and the most varied, with 14 subthemes. Attitudes toward NRP differed by type of NRP: of 72 publications discussing thoracoabdominal NRP, 22 (30.6%) were "In Favor," 39 (54.2%) were "Neutral," and 11 (15.3%) were "Against"; of 44 discussing abdominal NRP, 23 (52.3%) were "In Favor," 20 (45.5%) were "Neutral," and 1 (2.3%) was "Against." Attitudes differed by authors' country, degree, and affiliation, and by the clinical focus of the publishing journal. Overall, our review shows that the ethical and legal issues raised by NRP remain unresolved, and the debate centered on nonmaleficence.

Normothermic Regional Perfusion Experience of Organ Procurement Organizations in the US

Importance

Despite the unmet need for donor organs, organ use from donation after circulatory determination of death (DCD) donors has been limited by inferior transplant outcomes. Normothermic regional perfusion (NRP) improves recipient outcomes and organ utilization from DCD donors. There is variability in NRP policies and experience among US organ procurement organizations (OPOs).

Objectives

To determine OPO experience, identify operational inconsistencies, and explore needs related to NRP.

Design, Setting, and Participants

This survey study included 55 OPOs in the US that had recovered DCD organs and completed a survey on operational, administrative, and educational components related to NRP in November to December 2023. Data analysis was performed from February to April 2024.

Main Outcome and Measures

The primary outcome was the number of OPOs participating in and/or anticipating NRP participation. Secondary outcomes were NRP implementation barriers, OPO education practices, and future needs regarding consensus NRP recommendations and standards.

Results

Of 55 respondents, 11 (20%) were chief executive officers, 8 (15%) were chief operating officers, and 36 (65%) were medical directors or chief clinical officers. Forty-nine OPOs facilitated NRP cases: 26 OPOs (53%) facilitated both thoracoabdominal NRP (TA-NRP) and abdominal NRP (A-NRP) cases, 16 OPOs (33%) facilitated only TA-NRP, and 7 OPOs (14%) facilitated only A-NRP. OPOs reported 606 NRP cases (421 TA-NRP [69%], 185 A-NRP [31%]); median (range) case experience was 8 (1-52). Fifty-two of 55 OPOs (95%) thought standardized guidance documents would be helpful. All 49 OPOs facilitated NRP at a transplant center's request; 39 (80%) had NRP initiated by a nonlocal transplant center. Twenty-three of 49 OPOs (47%) participated in NRP without a policy and without a policy pending approval. Positive donor hospital feedback was received by 29 OPOs (59%), primarily focused on increased organs transplanted and prerecovery communication. Allocation challenges were experienced by 21 OPOs (43%); their median (range) case volume was higher than those with no reported allocation challenges (11 [3-52] vs 6.5 [1-29]; P = .03). Eleven OPOs (22%) had incorporated NRP into general donor hospital education.

Conclusions

In this survey study of US OPOs, wide variation existed with respect to NRP experience and practice. Allocation challenges occurred more frequently with increased NRP experience. NRP guidelines and standardization were desired by most OPOs to decrease allocation challenges and maximize the gift of organ donation.

Association of procurement technique with organ yield and cost following donation after circulatory death

Donation after circulatory death (DCD) could account for the largest expansion of the donor allograft pool in the contemporary era. However, the organ yield and associated costs of normothermic regional perfusion (NRP) compared to super-rapid recovery (SRR) with ex-situ normothermic machine perfusion, remain unreported. The Organ Procurement and Transplantation Network (December 2019 to June 2023) was analyzed to determine the number of organs recovered per donor. A cost analysis was performed based on our institution's experience since 2022. Of 43 502 donors, 30 646 (70%) were donors after brain death (DBD), 12 536 (29%) DCD-SRR and 320 (0.7%) DCD-NRP. The mean number of organs recovered was 3.70 for DBD, 3.71 for DCD-NRP (P < .001), and 2.45 for DCD-SRR (P < .001). Following risk adjustment, DCD-NRP (adjusted odds ratio 1.34, confidence interval 1.04-1.75) and DCD-SRR (adjusted odds ratio 2.11, confidence interval 2.01-2.21; reference: DBD) remained associated with greater odds of allograft nonuse. Including incomplete and completed procurement runs, the total average cost of DCD-NRP was $9463.22 per donor. By conservative estimates, we found that approximately 31 donor allografts could be procured using DCD-NRP for the cost equivalent of 1 allograft procured via DCD-SRR with ex-situ normothermic machine perfusion. In conclusion, DCD-SRR procurements were associated with the lowest organ yield compared to other procurement methods. To facilitate broader adoption of DCD procurement, a comprehensive understanding of the trade-offs inherent in each technique is imperative.

Ethical Issues in Normothermic Regional Perfusion in Controlled Organ Donation After Determination of Death by Circulatory Criteria: A Scoping Review

Normothermic regional perfusion (NRP) is a surgical technique that can improve the quality and number of organs recovered for donation after the determination of death by circulatory criteria. Despite its promise, adoption of NRP has been hindered because of unresolved ethical issues. To inform stakeholders, this scoping review provides an impartial overview of the major ethical controversies surrounding NRP. We undertook this review according to a modified 5-step methodology proposed by Arksey and O'Malley. Publications were retrieved through MEDLINE and Embase. Gray literature was sourced from Canadian organ donation organizations, English-language organ donation organization websites, and through our research networks. Three reviewers independently screened all documents for inclusion, extracted data, and participated in content analysis. Disagreements were resolved through consensus meetings. Seventy-one documents substantively engaging with ethical issues in NRP were included for full-text analysis. We identified 6 major themes encompassing a range of overlapping ethical debates: (1) the compatibility of NRP with the dead donor rule, the injunction that organ recovery cannot cause death, (2) the risk of donor harm posed by NRP, (3) uncertainties regarding consent requirements for NRP, (4) risks to stakeholder trust posed by NRP, (5) the implications of NRP for justice, and (6) NRP's potential to benefits of NRP for stakeholders. We found no agreement on the ethical permissibility of NRP. However, some debates may be resolved through additional empirical study. As decision-makers contemplate the adoption of NRP, it is critical to address the ethical issues facing the technique to ensure stakeholder trust in deceased donation and transplantation systems is preserved.

Changing landscape of liver transplant in the United States-time for a new innovative way to define and utilize the "non-standard liver allograft"-a proposal

Since the first liver transplant was performed over six decades ago, the landscape of liver transplantation in the US has seen dramatic evolution. Numerous advancements in perioperative and operative techniques have resulted in major improvements in graft and patient survival rates. Despite the increase in transplants performed over the years, the waitlist mortality rate continues to remain high. The obesity epidemic and the resultant metabolic sequelae continue to result in more marginal donors and challenging recipients. In this review, we aim to highlight the changing characteristics of liver transplant recipients and liver allograft donors. We focus on issues relevant in successfully transplanting a high model for end stage liver disease recipient. We provide insights into the current use of terms and definitions utilized to discuss marginal allografts, discuss the need to look into more consistent ways to describe these organs and propose two new concepts we coin as "Liver Allograft Variables" (LAV) and "Liver Allograft Composite Score" (LACS) for this. We discuss the development of spectrum of risk indexes as a dynamic tool to characterize an allograft in real time. We believe that this concept has the potential to optimize the way we allocate, utilize and transplant livers across the US.

American Society of Transplant Surgeons Normothermic Regional Perfusion Standards: Abdominal

BACKGROUND

Normothermic regional perfusion (NRP) has emerged as a vital technique in organ procurement, particularly in donation after circulatory death (DCD) cases, offering the potential to optimize organ utilization and improve posttransplant outcomes. Recognizing its significance, the American Society of Transplant Surgeons (ASTS) convened a work group to develop standardized recommendations for abdominal NRP in the United States.

METHODS

The workgroup, comprising experts in NRP, DCD, and transplantation, formulated recommendations through a collaborative process involving revisions and approvals by relevant committees and the ASTS council. Four key areas were identified for standardization: Preprocedure communication, NRP procedure, Terminology and documentation, and Mentorship/credentialing.

RESULTS

The recommendations encompass a range of considerations, including preprocedure communication protocols to facilitate informed decision-making by transplant centers and organ procurement organizations, procedural guidelines for NRP teams, uniform terminology to clarify the NRP process, and standards for mentorship and credentialing of NRP practitioners. Specific recommendations address logistical concerns, procedural nuances, documentation requirements, and the importance of ongoing quality assurance.

CONCLUSIONS

The standardized recommendations for abdominal NRP presented in this article aim to ensure consistency, safety, and efficacy in the organ procurement process. By establishing clear protocols and guidelines, the ASTS seeks to enhance organ utilization, honor donor wishes, and uphold public trust in the donation process. Implementation of these recommendations can contribute to the advancement of NRP practices and improve outcomes for transplant recipients.

Normothermic Regional Perfusion in Controlled Donation After the Circulatory Determination of Death: Understanding Where the Benefit Lies

Controlled donation after the circulatory determination of death (cDCDD) has emerged as a strategy to increase the availability of organs for clinical use. Traditionally, organs from cDCDD donors have been subject to standard rapid recovery (SRR) with poor posttransplant outcomes of abdominal organs, particularly the liver, and limited organ utilization. Normothermic regional perfusion (NRP), based on the use of extracorporeal membrane oxygenation devices, consists of the in situ perfusion of organs that will be subject to transplantation with oxygenated blood under normothermic conditions after the declaration of death and before organ recovery. NRP is a potential solution to address the limitations of traditional recovery methods. It has become normal practice in several European countries and has been recently introduced in the United States. The increased use of NRP in cDCDD has occurred as a result of a growing body of evidence on its association with improved posttransplant outcomes and organ utilization compared with SRR. However, the expansion of NRP is precluded by obstacles of an organizational, legal, and ethical nature. This article details the technique of both abdominal and thoracoabdominal NRP. Based on the available evidence, it describes its benefits in terms of posttransplant outcomes of abdominal and thoracic organs and organ utilization. It addresses cost-effectiveness aspects of NRP, as well as logistical and ethical obstacles that limit the implementation of this innovative preservation strategy.

Stepwise development and expansion of an abdominal normothermic regional perfusion program for donation after circulatory determination of death organ procurement

INTRODUCTION

Normothermic regional perfusion (NRP) represents an innovative technology that improves the outcomes for liver and kidney recipients of donation after circulatory determination of death (DCD) organs but protocols for abdominal-only NRP (A-NRP) DCD are lacking in the US.

METHODS

We describe the implementation and expansion strategies of a transplant-center-based A-NRP DCD program that has grown in volume, geographical reach, and donor acceptance parameters, presented as four eras.

RESULTS

In the implementation era, two donors were attempted, and one liver graft was transplanted. In the local expansion era, 33% of attempted donors resulted in transplantation and 42% of liver grafts from donors who died within the functional warm ischemic time (fWIT) limit were transplanted. In the Regional Expansion era, 25% of attempted donors resulted in transplantation and 50% of liver grafts from donors who died within the fWIT limit were transplanted. In the Donor Acceptance Expansion era, 46% of attempted donors resulted in transplantation and 72% of liver grafts from donors who died within the fWIT limit were transplanted. Eight discarded grafts demonstrated a potential opportunity for utilization.

CONCLUSION

The stepwise approach to building an A-NRP program described here can serve as a model for other transplant centers.