Six-month abdominal transplant recipient outcomes from donation after circulatory death heart donors: A retrospective analysis by procurement technique

The current landscape of in situ and ex situ machine perfusion utilization for liver grafts from cardiac donation after circulatory death donors in the US

Donation after circulatory death (DCD) is driving the increase in deceased organ donors in the United States. Normothermic regional perfusion (NRP) and ex situ machine perfusion (es-MP) have been instrumental in improving liver transplant outcomes and graft utilization. This study examines the current landscape of liver utilization from cardiac DCD donors in the United States. Using the United Network for Organ Sharing Standard Transplant Analysis and Research file, all adult (≥18 years old) DCD donors in the United States from which the heart was used for transplantation from October 1, 2020, to September 30, 2023, were compared by procurement technique (NRP versus super rapid recovery [SRR]) and storage strategy (es-MP versus static cold storage). One hundred eighty-eight livers were transplanted from 309 thoracoabdominal NRP donors (61% utilization) versus 305 (56%) liver transplants from 544 SRR donors. es-MP was used in 20% (n = 38) of NRP cases versus 32% (98) of SRR cases. Of the liver grafts, 281 (59%) were exposed to NRP, es-MP, or both. While there is widespread utilization of machine perfusion, more research is needed to determine optimal graft management strategies, particularly concerning the use of multiple technologies in complementary ways. More complete data collection is necessary at a national level to address these important research questions.

Transforming liver transplant allocation with artificial intelligence and machine learning: a systematic review

BACKGROUND

The principles of urgency, utility, and benefit are fundamental concepts guiding the ethical and practical decision-making process for organ allocation; however, LT allocation still follows an urgency model.

AIM

To identify and analyze data elements used in Machine Learning (ML) and Artificial Intelligence (AI) methods, data sources, and their focus on urgency, utility, or benefit in LT.

METHODS

A comprehensive search across Ovid Medline and Scopus was conducted for studies published from 2002 to June 2023. Inclusion criteria targeted quantitative studies using ML/AI for candidates, donors, or recipients. Two reviewers assessed eligibility and extracted data, following PRISMA guidelines.

RESULTS

A total of 20 papers were included, synthesizing results into five major categories. Eight studies were led by a Spanish team, focusing on donor-recipient matching and proposing machine learning models to predict post- LT survival. Other international studies addressed organ supply-demand issues and developed predictive models to optimize LT outcomes. The studies highlight the potential of ML/AI to enhance LT allocation and outcomes. Despite advancements, limitations included the lack of robust transplant-related benefit models and improvements in urgency models compared to MELD.

DISCUSSION

This review highlighted the potential of AI and ML to enhance liver transplant allocation and outcomes. Significant advancements were noted, but limitations such as the need for better urgency models and the absence of a transplant-related benefit model remain. Most studies emphasized utility, focusing on survival outcomes. Future research should address the interpretability and generalizability of these models to improve organ allocation and post-LT survival predictions.

Impact of dual thoracic recovery from circulatory death donors on heart and lung transplant outcomes

OBJECTIVES

Concomitant heart and lung recovery can result in increased operative complexity, ischemic time, and competition for resources and anatomic territory. Dual thoracic recovery from circulatory death donors may have additional risks that are not fully understood. We investigated the effects of dual heart and lung recovery from circulatory death donors on thoracic transplant outcomes.

METHODS

Using the United Network for Organ Sharing database, we categorized all adult thoracic circulatory death donor transplants from 2019 to 2023 by whether the donor heart, lung, or both (dual donors) were recovered. Heart and lung transplant outcomes were compared between dual recovery donors and heart-only or lung-only donors, respectively, using multivariable analyses.

RESULTS

Of the 2513 donors included, 42.9% were heart-only, 45.0% were lung-only, and 12.0% were dual donors. Recipients of dual versus heart-only donors had similar likelihood of post-transplant dialysis (18.9% vs 18.3%, P = .84), likelihood of stroke (2.9% vs 4.7%, P = .34), and 2-year risk of mortality (adjusted hazard ratio, 1.15 [95% CI, 0.90-1.47], P = .26), but lower likelihood of acute rejection (10.2% vs 16.1%, P = .04). Recipients of dual and lung-only donors had similar likelihood of predischarge acute rejection (7.6% vs 8.5%, P = .70), intubation at 72 hours (38.9% vs 45.1%, P = .13), and extracorporeal membrane oxygenation at 72 hours (13.1% vs 18.1%, P = .11), as well as 2-year risk of mortality (adjusted hazard ratio, 1.16 [95% CI, 0.74-1.82], P = .52).

CONCLUSIONS

Recovering both the heart and lungs from a circulatory death donor does not negatively impact transplant outcomes. Outcomes in this population should continue to be investigated as more data and longer-term follow-up become available.

Improved Outcomes and Resource Use With Normothermic Machine Perfusion in Liver Transplantation

Importance

Normothermic machine perfusion (NMP) has been shown to reduce peritransplant complications. Despite increasing NMP use in liver transplant (LT), there is a scarcity of real-world clinical experience data.

Objective

To compare LT outcomes between donation after brain death (DBD) and donation after circulatory death (DCD) allografts preserved with NMP or static cold storage (SCS).

Design, Setting, and Participants

This single-center, retrospective observational cohort study included all consecutive adult LTs performed between January 2019 and December 2023 at the Mayo Clinic in Arizona. Data analysis was performed between February 2024 and June 2024. Outcomes of DBD-SCS, DBD-NMP, DCD-SCS, and DCD-NMP transplants were compared.

Exposure

DBD and DCD livers preserved on NMP or SCS.

Main Outcomes and Measures

The primary outcomes were early allograft dysfunction (EAD), intraoperative transfusion, and post-LT hospital resource use, including length of stay (LOS) and readmissions. Secondary outcomes included acute kidney injury (AKI) and 1-year graft and patient survival.

Results

A total of 1086 LTs were included in the following 4 groups: DBD-SCS (n = 480), DBD-NMP (n = 63), DCD-SCS (n = 264), and DCD-NMP (n = 279). Among LT recipients, median (IQR) age was 60.0 years (52.0-66.0); 399 LT recipients (36.7%) were female. DCD-NMP had the lowest EAD rate (17.5%), followed by DCD-SCS (50.0%), DBD-NMP (36.8%), and DBD-SCS (27.3%) (P < .001). DCD-NMP had the lowest intraoperative transfusion requirement compared to all other groups. Hospital and intensive care unit (ICU) LOS were shortest in DCD-NMP (median [IQR] hospital LOS, 5.0 days [4.0-7.0]; P = .01; median [IQR] ICU LOS, 1.5 days [1.2-3.1]; P = .01). One-year cumulative readmission probability was 86% lower for DCD-NMP vs DCD-SCS (95% CI, 0.09-0.22; P < .001) and 53% lower for DBD-NMP vs DBD-SCS (95% CI, 0.26-0.87; P < .001). AKI events were lower in DCD-NMP (31.1%) vs DCD-SCS (47.4%) (P = .001). Compared to SCS, the NMP group had a 78% overall reduction in graft failure (hazard ratio [HR], 0.22; 95% CI, 0.10-0.49; P < .001). For those receiving DCD allografts, the risk reduction was even more pronounced, with an 87% decrease in graft failure (HR, 0.13; 95% CI, 0.05-0.33; P < .001). NMP was significantly protective from patient mortality vs SCS (HR, 0.31; 95% CI, 0.12-0.80; P = .02).

Conclusions and Relevance

In this observational high-volume cohort study, NMP significantly improved LT clinical outcomes and reduced hospital resource use, especially in DCD allografts. NMP may enhance access to LT by addressing the challenges historically linked with DCD liver use.

Impact of donor obesity on outcomes of donation after circulatory death heart transplantation

BACKGROUND

In the setting of the obesity epidemic and donor organ shortage in the United States, there is a growing need to expand the donor organ eligibility criteria for orthotopic heart transplantation (OHT). Donation after circulatory death (DCD) has emerged as a promising solution, but the outcomes with obese donor hearts in DCD OHT remains unknown.

METHODS

Using the United Network for Organ Sharing registry between 2019 and 2024, recipients of DCD OHT were stratified into 3 donor obesity categories by body mass index (BMI): underweight/normal (BMI <25 kg/m2), overweight (BMI 25-30 kg/m2), and obese (BMI >30 kg/m2). These cohorts were subgrouped by organ procurement strategy: direct procurement and preservation (DPP) or normothermic regional perfusion (NRP). Recipient and donor characteristics and risk factors for mortality were analyzed using Cox regression hazard models. Survival at 30 days, 1 year, and 5 years post-transplantation were analyzed using the Kaplan-Meier method.

RESULTS

We found no significant differences in patient and graft survival between donor BMI categories at all time points. Among recipients of overweight (hazard ratio [HR], 0.38; P = .0371) and obese (HR, 0.24; P = .0493) donor hearts, NRP was associated with decreased risk of mortality. Donor-recipient predicted heart mass (PHM) undermatching (defined as <86%) was associated with increased risk of mortality among underweight/normal weight donors (HR, 1.28; P = .0323) and overweight donors (HR, 1.08; P = .0382).

CONCLUSIONS

Donor obesity does not confer an increased risk of recipient mortality in DCD OHT, particularly when NRP is used. PHM undermatching continues to be associated with adverse outcomes in DCD OHT.

Review of Current Normothermic Regional Perfusion Practice in Pediatric Cardiac Donation

BACKGROUND

Cardiac allotransplantation is the optimal treatment for end-stage heart failure. However, organ supply remains the principal issue affecting patients. Pediatric patients present unique challenges resulting in long wait-list times and increased mortality. Donation after circulatory death with normothermic regional perfusion represents a method to increase the number of available organs in this population.

METHODS

Multiinstitutional expert consultation was sought to outline extant technical, ethical, and logistical issues with regard to normothermic regional perfusion cardiac donation techniques. Specific advantages in the pediatric population are highlighted, as well as technical considerations resulting in successful organ procurement.

RESULTS

The use of donation after circulatory death organs after normothermic regional perfusion in the United States is increasing and offers advantages to the pediatric heart failure population. Ethical reservations both nationally and abroad persist, namely pertaining to cerebral blood flow. This issue has led to variation in perception and use of normothermic regional perfusion, thus contributing to a discrepancy between donor and recipient locations. Procurement techniques and variations are described, with an introduction to program planning and protocol development. Training in technical aspects of the procedure is paramount for both the surgeon and support staff to construct a successful program, along with transparent protocols to mitigate ethical concerns.

CONCLUSIONS

Normothermic regional perfusion is relevant after donation after cardiac death in the pediatric population. Ethical and technical challenges remain, in concert with substantial domestic and international variation. Standardization of technique may serve to increase future use and increase the number of available hearts for transplantation, thereby reducing pediatric mortality.

Donation After Circulatory Death Cardiac Recovery Technique: Single-Center Observational Outcomes

BACKGROUND

Recovery of hearts from donation after circulatory death donors has been performed either with direct procurement and perfusion (DPP) using the TransMedics Organ Care System or with normothermic regional perfusion (NRP) with subsequent cold storage. It remains unclear which of these 2 strategies yields optimal posttransplant outcomes.

METHODS

All heart transplant recipients from donors after circulatory death donors at the Vanderbilt University Medical Center (Nashville, TN) were reviewed (February 2020 to January 2023). Recipients were stratified into an NRP or DPP cohort. All DPP recoveries were performed using the TransMedics Organ Care System. The key outcome was severe primary graft dysfunction at 24 hours, defined by the need for postoperative extracorporeal membrane oxygenation.

RESULTS

A total of 118 hearts were transplanted (NRP, 87; DPP, 31). Donors recovered using NRP were younger (25 years [interquartile range {IQR}, 21-31 years] vs 31 years [IQR, 24-37 years]; P = .008) and had shorter distance traveled (292 miles [158-516 miles] vs 449 miles [IQR, 248-635 miles]; P = .02). Recipient preoperative risk factors were similar between the groups. There was no difference in the incidence of severe primary graft dysfunction at 24 hours (NRP, 5.8%; and DPP, 12.9%; P = .24). However, ejection fraction at 7 days after transplantation was higher in the NRP group (65% [IQR, 60%-65%] vs 60% [IQR, 60%-68%]; P = .005). There was no difference in inotrope scores at 24 hours (P = 1.00) or 72 hours (P = .87) or in 30-day (NRP, 95% vs DPP, 97%; P = .75) and 1-year (NRP, 94% vs DPP, 86%; P = .19) survival.

CONCLUSIONS

NRP and DPP strategies for recovery of cardiac allografts yield comparable early allograft outcomes. Future studies are needed to confirm these findings in larger prospective cohorts.

Enhancing the usability of older DCD donors through strategic approaches in liver transplantation in the United States

The use of older donors after circulatory death (DCD) for liver transplantation (LT) has increased over the past decade. This study examined whether outcomes of LT using older DCD (≥50 y) have improved with advancements in surgical/perioperative care and normothermic machine perfusion (NMP) technology. A total of 7602 DCD LT cases from the United Network for Organ Sharing database (2003-2022) were reviewed. The impact of older DCD donors on graft survival was assessed using the Kaplan-Meier and HR analyses. In all, 1447 LT cases (19.0%) involved older DCD donors. Although there was a decrease in their use from 2003 to 2014, a resurgence was noted after 2015 and reached 21.9% of all LTs in the last 4 years (2019-2022). Initially, 90-day and 1-year graft survivals for older DCDs were worse than younger DCDs, but this difference decreased over time and there was no statistical difference after 2015. Similarly, HRs for graft loss in older DCD have recently become insignificant. In older DCD LT, NMP usage has increased recently, especially in cases with extended donor-recipient distances, while the median time from asystole to aortic cross-clamp has decreased. Multivariable Cox regression analyses revealed that in the early phase, asystole to cross-clamp time had the highest HR for graft loss in older DCD LT without NMP, while in the later phases, the cold ischemic time (>5.5 h) was a significant predictor. LT outcomes using older DCD donors have become comparable to those from young DCD donors, with recent HRs for graft loss becoming insignificant. The strategic approach in the recent period could mitigate risks, including managing cold ischemic time (≤5.5 h), reducing asystole to cross-clamp time, and adopting NMP for longer distances. Optimal use of older DCD donors may alleviate the donor shortage.

Utilization and outcomes of expanded criteria donors in adults with congenital heart disease

BACKGROUND

Use of donation after circulatory death (DCD) and hepatitis C virus (HCV) positive donors in heart transplantation have increased the donor pool. Given poor waitlist outcomes in the adult congenital heart disease (ACHD) population, we investigated waitlist outcomes associated with willingness to consider DCD and HCV+ offers and post-transplant outcomes following HCV+ and DCD transplantation for these candidates.

METHODS

Using the United Network for Organ Sharing database, we identified adult ACHD candidates and recipients listed or transplanted, respectively, between 01/01/2016 and 09/30/2023 for the HCV analysis and between 12/01/2019 and 09/30/2023 for the DCD analysis. Among candidates, we compared the cumulative incidence of transplant, with waitlist death/deterioration as a competing risk, by willingness to consider HCV+ and DCD offers. Among recipients of HCV+ (vs HCV-) and DCD (vs brain death [DBD]) transplants, we compared perioperative outcomes and post-transplant survival.

RESULTS

Of 1,436 ACHD candidates from 01/01/2016 to 09/30/2023, 37.0% were willing to consider HCV+ heart offers. Of 886 ACHD candidates from 12/01/2019 to 09/30/2023, 15.5% were willing to consider DCD offers. On adjusted analysis, willingness to consider HCV+ offers was associated with 84% increased likelihood of transplant, and willingness to consider DCD offers was associated with 56% increased likelihood of transplant. Of 904 transplants between 01/01/2016 and 09/30/2023, 6.4% utilized HCV+ donors, and of 540 transplants between 12/01/2019 and 09/30/2023, 6.9% utilized DCD donors. Recipients of HCV+ (vs HCV-) and DCD (vs DBD) heart transplants had similar likelihood of perioperative outcomes and 1-year survival.

CONCLUSIONS

ACHD candidates who were willing to consider HCV+ and DCD offers were more likely to be transplanted and had similar post-transplant outcomes compared to recipients of HCV- and DBD organs.

A cost comparison of liver acquisition fees for donation after circulatory death versus donation after brain death donors

Donation after circulatory death (DCD) donors now represent over 30% of the deceased donor pool in the United States. Compared to donation after brain death, DCD is less likely to result in transplantation. For each potential donor whose organs cannot be utilized for transplantation (ie, dry run), fees are associated with the attempted donation, which add to the overall costs of organ acquisition. To better characterize the true costs of DCD liver acquisition, we performed a cost comparison of the fees associated with organ acquisition for DCD versus donation after brain death at a single transplant institute that comprises 2 liver transplant centers. Cost, recipient, and transportation data for all cases, including fees associated with liver acquisition from July 1, 2019, to October 31, 2021, were collected. We found that the total cost of DCD liver acquisition per liver transplant was $15,029 more than that for donation after brain death donation, with 18% of the costs of the DCD transplant attributed to dry runs. Overall, the costs associated with DCD transplantation accounted for 34.5% of the total organ acquisition costs; however, DCD transplantation accounted for 30.3% of the transplantation volume. Because the expansion of DCD is essential to increasing the availability of liver grafts for transplantation, strategies need to be implemented to decrease the costs associated with dry runs, including using local recovery, transferring donors to hospitals close to transplant centers, and performing more prerecovery organ analysis. Moreover, these strategies are needed to ensure that financial disincentives to DCD procurement and utilization do not reverse the gains made by expanding the organ donor pool using machine perfusion technologies.

Outcomes following concomitant multiorgan heart transplantation from circulatory death donors: The United States experience

BACKGROUND

Donation after circulatory death (DCD) has reemerged as a method of expanding the donor heart pool. Given the high waitlist mortality of multiorgan heart candidates, we evaluated waitlist outcomes associated with willingness to consider DCD offers and post-transplant outcomes following DCD transplant for these candidates.

METHODS

We identified adult multiorgan heart candidates and recipients between January 1, 2020 and March 31, 2023 nationally. Among candidates that met inclusion criteria, we compared the cumulative incidence of transplant, with waitlist death/deterioration as a competing risk, by willingness to consider DCD offers. Among recipients of DCD versus brain death (DBD) transplants, we compared perioperative outcomes and post-transplant survival.

RESULTS

Of 1,802 heart-kidney, 266 heart-liver, and 440 heart-lung candidates, 15.8%, 12.4%, and 31.1%, respectively, were willing to consider DCD offers. On adjusted analysis, willingness to consider DCD offers was associated with higher likelihood of transplant for all multiorgan heart candidates and decreased likelihood of waitlist deterioration for heart-lung candidates. Of 1,100 heart-kidney, 173 heart-liver, and 159 heart-lung recipients, 5.4%, 2.3%, and 2.5%, respectively, received DCD organs. Recipients of DCD and DBD heart-kidney transplants had a similar likelihood of perioperative outcomes and 1-year survival. All other DCD multiorgan heart recipients have survived to the last follow-up.

CONCLUSIONS

Multiorgan heart candidates who were willing to consider DCD offers had favorable waitlist outcomes, and heart-kidney recipients of DCD transplants had similar post-transplant outcomes to recipients of DBD transplants. We recommend the use of DCD organs to increase the donor pool for these high-risk candidates.

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.

Post-transplant survival after normothermic regional perfusion versus direct procurement and perfusion in donation after circulatory determination of death in heart transplantation

BACKGROUND

Since 2019, the annual transplantation rate of hearts donated following circulatory death (DCD) has increased significantly in the United States. The 2 major heart procurement techniques following circulatory death are direct procurement and perfusion (DPP) and normothermic regional perfusion (NRP). Post-transplant survival for heart recipients has not been compared between these 2 techniques.

METHODS

This observational study uses data on adult heart transplants from donors after circulatory death from January 1, 2019 to December 31, 2021 in the Scientific Registry of Transplant Recipients. We identified comparable transplant cases across procurement types using propensity-score matching and measured the association between procurement technique and 1-year post-transplant survival using Kaplan-Meier and Cox proportional hazards model stratefied by matching pairs.

RESULTS

Among 318 DCD heart transplants, 216 (68%) were procured via DPP, and 102 (32%) via NRP. Among 22 transplant centers that accepted circulatory-death donors, 3 used NRP exclusively, and 5 used both procurement techniques. After propensity-score matching on recipient and donor factors, there was no significant difference in 1-year post-transplant survival (93.1% for NRP vs 91.1% for DPP, p = 0.79) between procurement techniques.

CONCLUSIONS

NRP and DPP procurements are associated with similar 1-year post-transplant survival. If NRP is ethically permissible and improves outcomes for abdominal organs, it should be the preferred procurement technique for DCD hearts.

Abdominal normothermic regional perfusion in the United States: current state and future directions

PURPOSE OF REVIEW

Normothermic regional perfusion (NRP) is a novel procurement technique for donation after circulatory death (DCD) in the United States. It was pioneered by cardiothoracic surgery programs and is now being applied to abdominal-only organ donors by abdominal transplant programs.

RECENT FINDINGS

Liver and kidney transplantation from thoracoabdominal NRP (TA-NRP) donors in the United States was found to have lower rates of delayed kidney graft function and similar graft and patient survival versus recipients of cardiac super rapid recovery (SRR) DCD donors. The excellent outcomes with NRP have prompted the expansion of NRP technology to abdominal transplant programs.

SUMMARY

Excellent early outcomes with liver and kidney transplantation have prompted the growth of NC-NRP procurement for abdominal-only DCD donors across the US, and now requires standardization of technical and nontechnical aspects of this procedure.

Normothermic regional perfusion procurement for abdominal organ donors: techniques and troubleshooting

PURPOSE OF REVIEW

Normothermic regional perfusion (NRP) is a novel procurement technique for donation after circulatory death (DCD) in the United States. It was pioneered by cardiothoracic surgery programs and is now being applied to abdominal-only organ donors by abdominal transplant programs. Multiple technical approaches can be used for abdominal-only NRP DCD donors and this review describes these techniques.

RECENT FINDINGS

NRP has been associated with higher utilization of organs, particularly liver and heart grafts, from DCD donors and with better recipient outcomes. There are lower rates of delayed graft function in kidney transplant recipients and lower rates of ischemic cholangiopathy in liver transplant recipients. These benefits are driving increased interest from abdominal transplant programs in using NRP for DCD procurements.

SUMMARY

This paper describes the technical aspects of NRP DCD that allow for maximization of its use based on different donor and policy characteristics.

Thoraco-abdominal normothermic regional perfusion for thoracic transplantation in the United States: current state and future directions

PURPOSE OF REVIEW

To provide an update regarding the state of thoracoabdominal normothermic regional perfusion (taNRP) when used for thoracic organ recovery.

RECENT FINDINGS

taNRP is growing in its utilization for thoracic organ recovery from donation after circulatory death donors, partly because of its cost effectiveness. taNRP has been shown to yield cardiac allograft recipient outcomes similar to those of brain-dead donors. Regarding the use of taNRP to recover donor lungs, United Network for Organ Sharing (UNOS) analysis shows that taNRP recovered lungs are noninferior, and taNRP has been used to consistently recover excellent lungs at high volume centers. Despite its growth, ethical debate regarding taNRP continues, though clinical data now supports the notion that there is no meaningful brain perfusion after clamping the aortic arch vessels.

SUMMARY

taNRP is an excellent method for recovering both heart and lungs from donation after circulatory death donors and yields satisfactory recipient outcomes in a cost-effective manner. taNRP is now endorsed by the American Society of Transplant Surgeons, though ethical debate continues.

US Liver Transplant Outcomes After Normothermic Regional Perfusion vs Standard Super Rapid Recovery

Importance

Normothermic regional perfusion (NRP) is an emerging recovery modality for transplantable allografts from controlled donation after circulatory death (cDCD) donors. In the US, only 11.4% of liver recipients who are transplanted from a deceased donor receive a cDCD liver. NRP has the potential to safely expand the US donor pool with improved transplant outcomes as compared with standard super rapid recovery (SRR).

Objective

To assess outcomes of US liver transplants using controlled donation after circulatory death livers recovered with normothermic regional perfusion vs standard super rapid recovery.

Design, Setting, and Participants

This was a retrospective, observational cohort study comparing liver transplant outcomes from cDCD donors recovered by NRP vs SRR. Outcomes of cDCD liver transplant from January 2017 to May 2023 were collated from 17 US transplant centers and included livers recovered by SRR and NRP (thoracoabdominal NRP [TA-NRP] and abdominal NRP [A-NRP]). Seven transplant centers used NRP, allowing for liver allografts to be transplanted at 17 centers; 10 centers imported livers recovered via NRP from other centers.

Exposures

cDCD livers were recovered by either NRP or SRR.

Main Outcomes and Measures

The primary outcome was ischemic cholangiopathy (IC). Secondary end points included primary nonfunction (PNF), early allograft dysfunction (EAD), biliary anastomotic strictures, posttransplant length of stay (LOS), and patient and graft survival.

Results

A total of 242 cDCD livers were included in this study: 136 recovered by SRR and 106 recovered by NRP (TA-NRP, 79 and A-NRP, 27). Median (IQR) NRP and SRR donor age was 30.5 (22-44) years and 36 (27-49) years, respectively. Median (IQR) posttransplant LOS was significantly shorter in the NRP cohort (7 [5-11] days vs 10 [7-16] days; P < .001). PNF occurred only in the SRR allografts group (n = 2). EAD was more common in the SRR cohort (123 of 136 [56.1%] vs 77 of 106 [36.4%]; P = .007). Biliary anastomotic strictures were increased 2.8-fold in SRR recipients (7 of 105 [6.7%] vs 30 of 134 [22.4%]; P = .001). Only SRR recipients had IC (0 vs 12 of 133 [9.0%]; P = .002); IC-free survival by Kaplan-Meier was significantly improved in NRP recipients. Patient and graft survival were comparable between cohorts.

Conclusion and Relevance

There was comparable patient and graft survival in liver transplant recipients of cDCD donors recovered by NRP vs SRR, with reduced rates of IC, biliary complications, and EAD in NRP recipients. The feasibility of A-NRP and TA-NRP implementation across multiple US transplant centers supports increasing adoption of NRP to improve organ use, access to transplant, and risk of wait-list mortality.

Single center utilization and post-transplant outcomes of thoracoabdominal normothermic regional perfusion deceased cardiac donor organs

INTRODUCTION

Thoracoabdominal normothermic regional perfusion (TA-NRP) following cardiac death is an emerging multivisceral organ procurement technique. Recent national studies on outcomes of presumptive TA-NRP-procured organs are limited by potential misclassification since TA-NRP is not differentiated from donation after cardiac death (DCD) in registry data.

METHODS

We studied 22 donors whose designees consented to TA-NRP and organ procurement performed at our institution between January 20, 2020 and July 3, 2022. We identified these donors in SRTR to describe organ utilization and recipient outcomes and compared them to recipients of traditional DCD (tDCD) and donation after brain death (DBD) organs during the same timeframe.

RESULTS

All 22 donors progressed to cardiac arrest and underwent TA-NRP followed by heart, lung, kidney, and/or liver procurement. Median donor age was 41 years, 55% had anoxic brain injury, 45% were hypertensive, 0% were diabetic, and median kidney donor profile index was 40%. TA-NRP utilization was high across all organ types (88%-100%), with a higher percentage of kidneys procured via TA-NRP compared to tDCD (88% vs. 72%, p = .02). Recipient and graft survival ranged from 89% to 100% and were comparable to tDCD and DBD recipients (p ≥ .2). Delayed graft function was lower for kidneys procured from TA-NRP compared to tDCD donors (27% vs. 44%, p = .045).

CONCLUSION

Procurement from TA-NRP donors yielded high organ utilization, with outcomes comparable to tDCD and DBD recipients across organ types. Further large-scale study of TA-NRP donors, facilitated by its capture in the national registry, will be critical to fully understand its impact as an organ procurement technique.

Kidney Donation After Circulatory Death Using Thoracoabdominal Normothermic Regional Perfusion: The Largest Report of the United States Experience

BACKGROUND

Thoracoabdominal normothermic regional perfusion (TA-NRP) has been increasingly used for donation after circulatory death (DCD) procurements in the United States. We present the largest report of outcomes of kidney transplants performed using DCD donor grafts perfused with TA-NRP.

METHODS

Adult DCD kidney transplants between 2020 and 2022 in the United Network for Organ Sharing database were included. Donors with ≥50 min between asystole and aortic cross-clamp time in which the heart was also transplanted were considered TA-NRP donors. All other donors were considered direct recovery donors. Multivariable regressions were used to assess delayed graft function, as well as posttransplant survival and all-cause graft failure at 30, 90, and 180 d. A propensity-matched analysis of cohorts matched on donor Kidney Donor Profile Index was performed.

RESULTS

Of the 16 140 total DCD kidney transplants performed during the study period, 306 (1.9%) used TA-NRP. TA-NRP donors were younger ( P  < 0.001) and had lower Kidney Donor Profile Index ( P  < 0.001) compared with direct recovery donors. Recipients receiving grafts recovered using TA-NRP were younger ( P  < 0.001) and more likely to be blood group O ( P  < 0.001). Transplants using TA-NRP had lower likelihood of delayed graft function (adjusted odds ratio 0.22 [95% confidence interval, 0.15-0.31], P  < 0.001) but similar 180-d survival ( P  = 0.8) and all-cause graft failure ( P  = 0.3) as transplants using direct recovery grafts. These inferences were unchanged on propensity-matched analysis.

CONCLUSIONS

Our results demonstrate that kidney transplants using TA-NRP DCD allografts have positive short-term mortality and graft survival outcomes, with significantly decreased rates of delayed graft function compared with direct recovery DCD grafts.

The American Society of Transplant Surgeons Consensus Statement on Normothermic Regional Perfusion

On June 3, 2023, the American Society of Transplant Surgeons convened a meeting in San Diego, California to (1) develop a consensus statement with supporting data on the ethical tenets of thoracoabdominal normothermic regional perfusion (NRP) and abdominal NRP; (2) provide guidelines for the standards of practice that should govern thoracoabdominal NRP and abdominal NRP; and (3) develop and implement a central database for the collection of NRP donor and recipient data in the United States. National and international leaders in the fields of neuroscience, transplantation, critical care, NRP, Organ Procurement Organizations, transplant centers, and donor families participated. The conference was designed to focus on the controversial issues of neurological flow and function in donation after circulatory death donors during NRP and propose technical standards necessary to ensure that this procedure is performed safely and effectively. This article discusses major topics and conclusions addressed at the meeting.

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

BACKGROUND

Normothermic regional perfusion (NRP) is a technique that is intended to enhance organ transplant outcomes from donation circulatory death (DCD) donors.

STUDY DESIGN

A retrospective analysis of data from the Scientific Registry of Transplant Recipients was performed. DCD donors were screened for inclusion based on date of donation 2020 or later, and whether the heart was also recovered for transplantation. We grouped donors as either donation after brain death or DCD. DCD donors were further divided into groups including those in which the heart was not recovered for transplant (Non-Heart DCD) and those in which it was, based on recovery technique (thoracoabdominal-NRP [TA-NRP] Heart DCD and Super Rapid Recovery Heart DCD).

RESULTS

A total of 219 kidney transplant recipients receiving organs from TA-NRP Heart DCD donors were compared to 436 SRR Super Rapid Recovery DCD, 10,630 Super Rapid Recovery non-heart DCD, and 27,820 donations after brain death recipients. Kidney transplant recipients of TA-NRP DCD allografts experienced shorter length of stay, lower rates of delayed graft function, and lower serum creatinine at the time of discharge when compared with recipients of other DCD allografts.

CONCLUSIONS

Our analysis demonstrates superior early kidney allograft function when TA-NRP is used for DCD organ recovery.