Donation after circulatory death heart transplantation using normothermic regional perfusion:The NYU Protocol

Innovative strategies to increase cardiac donor availability

Heart transplantation is a life-saving procedure for many people throughout the world. Data shows that in 2024, there was an increase in the volume of adult heart transplantation in the United States even as there was a decrease in the volume of pediatric heart transplantation to the lowest volume in a decade. Organ availability remains a major limiting factor affecting transplant volume. This mandates that innovation must take place to increase the supply of donor organs. While some strategies such as donation after cardiac death, hepatitis C virus + transplantation, and ABO-incompatible transplantation have increased the pool for donation, it still falls short of meeting the demand. Other proposed strategies include splitting the donor heart to provide multiple partial heart transplants, domino partial heart transplantation, changes in legislation including opt-out legislation, and xenotransplantation. Further evolution and refinement of these strategies will make a meaningful impact on patients awaiting life-saving heart transplants.

Outcomes of Donation After Circulatory Death Heart Transplantation Using Normothermic Regional Perfusion

Background

Donation after circulatory death (DCD) with cardiopulmonary bypass for thoracoabdominal normothermic regional perfusion (TA-NRP) has led to increased use of donor hearts. Rejection rates and long-term survival outcomes are not known.

Methods

A single-center retrospective cohort review of patients who underwent DCD heart transplantation from January 2020 to December 2023 was performed. Donor and recipient characteristics, operative characteristics, and posttransplantation outcomes were analyzed. Subgroup analysis comparing co-localized vs distant donors and recipients was performed. The primary end point was 1-year survival. Secondary end points included incidences of primary graft dysfunction (PGD), cardiac allograft vasculopathy (CAV), rejection rate, and overall mortality. Our TA-NRP protocol has remained the same, consisting of sternotomy, ligation of aortic arch vessels, establishment of cardiopulmonary bypass, reintubation, resuscitation of the heart, and cold static storage during transport.

Results

In total, 32 recipients underwent DCD heart transplantation, including 26 isolated hearts, 3 heart-lungs, and 3 heart-kidneys. The median age was 56 years for recipients and 39 years for donors; 21 donors and recipients were co-localized, whereas 11 were distant. One-year survival was 100%. Two patients required mechanical circulatory support for PGD. Four patients experienced grade 2R acute cellular rejection. Five patients had grade 1 CAV at 1 year. On subgroup analysis, distant donors and recipients had longer warm (47 vs 30 minutes; P < .005) and cold (213 vs 76 minutes; P < .005) ischemia times, without any other differences.

Conclusions

Outcomes after DCD heart transplantation using TA-NRP remain encouraging with acceptable rates of rejection, PGD, CAV, and survival at 1 year.

Thoracoabdominal Normothermic Regional Perfusion and Donation After Circulatory Death Lung Use

Importance

Donation after circulatory death (DCD) heart procurement has increased, but concerns remain about the effect of simultaneous heart and lung procurement, particularly with thoracoabdominal normothermic regional perfusion (TA-NRP), on the use of DCD lungs. Previous analyses exclude critical donor factors and organ nonuse, and rapidly rising DCD use may bias comparisons to historical controls.

Objective

To use validated risk-adjusted models to assess whether DCD heart procurement via TA-NRP and direct procurement is associated with lung use.

Design, Setting, and Participants

This retrospective cohort study involved adult DCD donors between January 1, 2019, and September 30, 2024, listed in the Scientific Registry of Transplant Recipients (SRTR). The SRTR deceased donor yield model was used to develop an observed to expected (O:E) yield ratio of lung use obtained through DCD among 4 cohorts: cardiac DCD donors vs noncardiac DCD donors and cardiac DCD donors undergoing TA-NRP vs direct procurement. Temporal trends in O:E ratios were analyzed with the Cochran-Armitage test.

Main Outcomes and Measures

The O:E ratios of DCD lung use.

Results

Among 24 431 DCD donors (15 878 [65.0%] male; median [IQR] age, 49.0 [37.0-58.0] years), 22 607 were noncardiac DCD (14 375 [63.6%] male; median [IQR] age, 51.0 [39.0-58.0] years) and 1824 were cardiac DCD (1503 [82.4%] male; median [IQR] age, 32.0 [26.0-38.0] years) donors; noncardiac DCD donors were more likely to be smokers (6873 [30.4%] vs 227 [12.4%]; P < .001). Among cardiac DCD donors, 325 underwent TA-NRP, while 712 underwent direct procurement. TA-NRP donors had shorter median (IQR) lung ischemic times (6.07 [4.38-9.56] hours vs 8.12 [6.16-12.00] hours; P < .001) and distances to recipient hospitals (222 [9-626] nautical miles vs 331 [159-521] nautical miles; P = .050) than direct procurement donors. Lung use was higher among cardiac DCD donations compared with noncardiac DCD donations (16.7% vs 4.4%, P < .001). Within the cardiac DCD cohort, lung use was similar between TA-NRP and direct procurement (19.1% vs 18.7%; P = .88) cohorts. Both noncardiac DCD and cardiac DCD donors had observed lung yields greater than expected (O:E, 1.29 [95% CI, 1.21-1.35] and 1.79 [95% CI, 1.62-1.96]; both P < .001), although cardiac DCD yield was significantly higher than noncardiac DCD yield (P < .001). Both TA-NRP and direct procurement lung yields were greater than expected (O:E, 2.00 [95% CI, 1.60-2.43] and 1.77 [95% CI, 1.52-1.99]; both P < .001) but were not significantly different from each other (P = .83). The O:E ratios did not change significantly over time across all cohorts. Among recipients, the TA-NRP cohort experienced significantly better 90-day mortality (0 of 62 vs 9 of 128 patients [7.0%]; P = .03) and overall survival (4 of 62 patients [6.5%] vs 21 of 128 patients [16.4%]; P = .04) rates compared with the direct procurement cohort.

Conclusions and Relevance

In this cohort study of DCD donors, concomitant heart procurement provided better-than-expected rates of lung use as assessed with validated O:E use ratios regardless of procurement technique. The findings also suggest a survival benefit with improved 90-day and overall survival rates for the TA-NRP cohort compared with the direct procurement cohort. Policies should be developed to maximize the benefits of these donations.

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.

Rise of the machines: Normothermic regional perfusion use in heart transplantation in the United States

BACKGROUND

Normothermic regional perfusion (NRP) and direct procurement and perfusion (DPP) allow for transplantation with donation after circulatory death (DCD) hearts. This study aimed to characterize the use of and variations in NRP and DPP for DCD transplants in the United States.

METHODS

Heart transplants performed between December 1, 2019 and March 31, 2024, were identified from the United Network for Organ Sharing database. DPP and NRP procurement strategies were classified based on previously published methods. The groups were compared, and survival was assessed using Kaplan-Meier methods. Geographic and center variability was categorized using encrypted data.

RESULTS

There were 595 NRP transplants and 625 DPP transplants. Distance traveled and out-of-body time were significantly lower for the NRP group (P < .01 for both). There were no significant differences in postoperative dialysis, stroke, or 1-year survival between the 2 groups; however, the rate of postoperative pacemaker placement was higher with NRP (P < .05). From 2019 to 2024, 54 of 61 centers (88.5%) used NRP, 50 of 61 centers (82%) used DPP, and 43 of 61 centers (70.5%) used both procurement techniques, with NRP the more popular DCD procurement technique. Geographically, NRP was more prevalent in regions 2, 5, and 8 used, whereas DPP was most prevalent in regions 1, 3, and 10.

CONCLUSIONS

The use of NRP is increasing in the United States, with tremendous growth seen since its introduction several years ago. Significant variation remains in the use of NRP and DPP, and further exploration of the impact of each procurement and preservation strategy on transplantation outcomes is needed.

Developing a thoracoabdominal normothermic regional perfusion (TA-NRP) program for the recovery of organs for thoracic transplant: lessons from the United States experience

Background

Heart and lung transplantation remain efficacious treatments for patients with end-stage cardiopulmonary failure. However, donor shortages remain a challenge to both providers and patients. Thoracoabdominal normothermic regional perfusion (TA-NRP) has been increasingly adopted to decrease organ ischemia from circulatory death donors and therefore increase the number of organs available for transplantation. Despite initial success, data on program genesis and implementation are limited. The aim of this manuscript is to characterize essential human resources, lessons, and key considerations needed to improve TA-NRP dissemination and thus adoption.

Methods

Single-center evaluation of a TA-NRP program was conducted using a retrospective cohort study design. All procurements performed using TA-NRP were included. Quantitative data were summarized. Descriptive elements of programmatic genesis, implementation, and experience were summarized using an inductive reasoning approach.

Results

Thirty TA-NRP procurements were performed. The average time from incision to TA-NRP initiation was 7±2 minutes and total time on TA-NRP was 87±28 minutes. In simple regression analysis, the average total TA-NRP time was noted to increase by approximately 0.86 minutes per procurement [95% confidence interval (CI): -0.10, 1.82, P=0.08], while the average warm ischemia time was noted to decrease by approximately 0.03 minutes per procurement (95% CI: -0.13, 0.07, P=0.43). Key programmatic elements during planning and implementation were identification of key stakeholders, early communication, proactive navigation of ethical concerns, staffing and equipment needs, and development of TA-NRP algorithms for pre, intra- and post-donation phases of care.

Conclusions

Development of a TA-NRP program is both feasible and easily implemented at institutions with pre-existing organ donation after circulatory death (DCD) procurement experience. Early identification of key stakeholders with frequent communication identified areas in need of expanded resources and addressed early ethical concerns, while local implementation efforts supported operationalization of existing infrastructure for TA-NRP procurements.

Heart transplantation from donation after circulatory death: a meta-analysis of national registries

Background

Although it has been widely recognized that heart transplantation (HT) following donation after circulatory death (DCD) can be a successful strategy to expand the donor pool, its clinical outcomes compared to donation after brain death (DBD) are still the subject of intense investigation. We reviewed the clinical characteristics of HT after DCD from the three largest multicenter nationwide registries, highlighting technical aspects, donor and recipient selection, and early outcomes. Moreover, we performed a meta-analysis of survival outcomes of DCD vs. DBD using reconstructed individual patient time-to-event data.

Methods

The PubMed, Web of Science, and Scopus databases were searched in January 2024 to identify the most recent reports from three large multicenter nationwide registries (United States, United Kingdom, and Australia) of HT after DCD. Clinical characteristics were summarized using descriptive statistics, and survival curves were reconstructed for DBD using individual patient time-to-event data. The pooled hazard ratio (HR) with confidence interval (CI) was calculated via Cox regression.

Results

A total of 646 DCD HT patients and 7,253 DBD controls were included in this review. In the majority of cases, donors were young males. The mean age of recipients ranged from 48 to 57 years, and the majority were males with idiopathic dilated cardiomyopathy. Up to 40% of patients required postoperative mechanical circulatory support with extracorporeal membrane oxygenation (ECMO). The meta-analysis estimated a pooled 1-year survival of 91.1% (95% CI: 88.6-93.7%) and 90.1% (95% CI: 89.4-90.8%) for DCD and DBD patients, respectively (P=0.91), with a pooled HR of 0.88 (95% CI: 0.65-1.20).

Conclusions

Although the generally more favorable clinical profile of DCD donors and recipients may constitute a potential selection bias, our meta-analysis documented similar early and medium-term survival outcomes for DCD and DBD HT.

Consensus Statement: Technical Standards for Thoracoabdominal Normothermic Regional Perfusion

BACKGROUND

Thoracoabdominal normothermic regional perfusion (TA-NRP) has emerged as a powerful technique for optimizing organ procurement from donation after circulatory death donors. Despite its rapid adoption, standardized guidelines for TA-NRP implementation are lacking, prompting the need for consensus recommendations to ensure safe and effective utilization of this technique.

METHODS

A working group composed of members from The American Society of Transplant Surgeons, The International Society of Heart and Lung Transplantation, The Society of Thoracic Surgeons, and The American Association for Thoracic Surgery was convened to develop technical guidelines for TA-NRP. The group systematically reviewed existing literature, consensus statements, and expert opinions to identify key areas requiring standardization, including predonation evaluation, intraoperative management, postdonation procedures, and future research directions.

RESULTS

The working group formulated recommendations encompassing donor evaluation and selection criteria, premortem testing and therapeutic interventions, communication protocols, and procedural guidelines for TA-NRP implementation. These recommendations aim to facilitate coordination among transplant teams, minimize variability in practice, and promote transparency and accountability throughout the TA-NRP process.

CONCLUSIONS

The consensus guidelines presented herein serve as a comprehensive framework for the successful and ethical implementation of TA-NRP programs in organ procurement from donation after circulatory death donors. By providing standardized recommendations and addressing areas of uncertainty, these guidelines aim to enhance the quality, safety, and efficiency of TA-NRP procedures, ultimately contributing to improved outcomes for transplant recipients.

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.

Donation After Circulatory Death Heart Transplantation: A Narrative Review

Heart transplantation is the definitive treatment for refractory, end-stage heart failure. The number of patients awaiting transplantation far exceeds available organs. In an effort to expand the donor pool, donation after circulatory death (DCD) heart transplantation has garnered renewed interest. Unlike donation after brain death, DCD donors do not meet the criteria for brain death and are dependent on life-sustaining therapies. Procurement can include a direct strategy or a normothermic regional perfusion, whereby there is restoration of perfusion to the organ before explantation. There are new developments in cold storage and ex vivo perfusion strategies. Since its inception, there has been a steady improvement in post-transplant outcomes, largely attributed to advancements in operative and procurement strategies. In this narrative review, the authors address the unique considerations of DCD heart transplantation, including withdrawal of care, the logistics of procuring and resuscitating organs, outcomes compared with standard donation after brain death, and ethical considerations.

Consensus Statement: Technical Standards for Thoracoabdominal Normothermic Regional Perfusion

BACKGROUND

Thoracoabdominal normothermic regional perfusion (TA-NRP) has emerged as a powerful technique for optimizing organ procurement from donation after circulatory death donors. Despite its rapid adoption, standardized guidelines for TA-NRP implementation are lacking, prompting the need for consensus recommendations to ensure safe and effective utilization of this technique.

METHODS

A working group composed of members from The American Society of Transplant Surgeons, The International Society of Heart and Lung Transplantation, The Society of Thoracic Surgeons, and The American Association for Thoracic Surgery was convened to develop technical guidelines for TA-NRP. The group systematically reviewed existing literature, consensus statements, and expert opinions to identify key areas requiring standardization, including predonation evaluation, intraoperative management, postdonation procedures, and future research directions.

RESULTS

The working group formulated recommendations encompassing donor evaluation and selection criteria, premortem testing and therapeutic interventions, communication protocols, and procedural guidelines for TA-NRP implementation. These recommendations aim to facilitate coordination among transplant teams, minimize variability in practice, and promote transparency and accountability throughout the TA-NRP process.

CONCLUSIONS

The consensus guidelines presented herein serve as a comprehensive framework for the successful and ethical implementation of TA-NRP programs in organ procurement from donation after circulatory death donors. By providing standardized recommendations and addressing areas of uncertainty, these guidelines aim to enhance the quality, safety, and efficiency of TA-NRP procedures, ultimately contributing to improved outcomes for transplant recipients.

Successful Recovery of Cardiac Function Following 20 min of a No-touch Period in a Donation After Circulatory Death: A Case Report

BACKGROUND

Withdrawal of life-sustaining therapy (WLST) performed in the circulatory determination of death (DCD) donors leads to cardiac arrest, challenging the utilization of the myocardium for transplantation. The rapid initiation of normothermic regional perfusion or extracorporeal membrane oxygenation after death helps to optimize organs before implantation. However, additional strategies to mitigate the effects of stress response during WLST, hypoxic/ischemic injury, and reperfusion injury are required to allow myocardium recovery.

METHODS

To this aim, our team routinely used a preconditioning protocol for each DCD donation before and during the WLST and after normothermic regional perfusion/extracorporeal membrane oxygenation. The protocol includes pharmacological treatments combined to reduce oxidative stress (melatonin, N -acetylcysteine, and ascorbic acid), improve microcirculation (statins), and mitigate organ's ischemic injury (steroids) and organ ischemia/reperfusion injury (remifentanil and sevoflurane when the heart is available for transplantation).

RESULTS

This report presents the first case of recovery of cardiac function, with the only support of normothermic regional reperfusion, following 20 min of a no-touch period and 41 min of functional warm ischemic time in a DCD donor after the preconditioning protocol.

CONCLUSIONS

Our protocol seems to be effective in abolishing the stress response during WLST and, on the other hand, particularly organ protective (and heart protective), giving a chance to donate organs less impaired from ischemia/reperfusion injury.

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.

Outcomes of lung and heart-lung transplants utilizing donor after circulatory death with thoracoabdominal normothermic regional perfusion

Background

Donation after circulatory death with thoracoabdominal normothermic regional perfusion (DCD-NRP) for cardiac transplant has promising results, though data for lung transplant is lacking. This study evaluates lung transplant outcomes using DCD-NRP allografts.

Methods

All patients who underwent lung transplantation (LT) from June 1, 2020, to July 5, 2023, at a single institution were evaluated. Recipients received organs from DCD-NRP or brain dead (control) donors (donation after brain death (DBD)). All DCD-NRP were adult, primary bilateral LT (BLT) without preoperative extracorporeal membrane oxygenation (ECMO). Inclusion criteria for controls were age >18 years, BLT, no preoperative ECMO, and primary transplantation. Comparison was separated by LT or heart-lung transplant (HLT). The primary outcome was primary graft dysfunction (PGD) grade 3 at 72 hours.

Results

There were 8 LT and 3 HLT in the DCD-NRP cohort, and 138 BLT and 7 HL DBD controls. PGD grade 3 at 72 hours was 0% in the entire DCD-NRP cohort (vs control: 9.4% LT and 0% HLT). There were no statistically significant differences in donor and recipient characteristics, though DCD-NRP HLT had significantly shorter ischemic time (85 vs 200 minutes, p < 0.02). Thirty-day and 90-day mortality and 1-year survival are similar in both cohorts for LT and HLT. To date, DCD-NRP recipients are all on room air, with 0% acute cellular rejection rate and 91% (10/11) without chronic rejection. The lung utilization rate of evaluated DCD-NRP donors was 100%.

Conclusions

Initial results of LT using DCD-NRP organs demonstrate similar PGD grade 3 at 72 hours and similar survival to standard donors.

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.

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.

Modern advances in heart transplantation

Heart transplantation (HTx) is the only definitive therapy for patients with end stage heart disease. With the increasing global prevalence of heart failure, the demand for HTx has continued to grow and outpace supply. In this paper, we will review advances in the field of HTx along the clinical journey of a HTx recipient. Starting with the sensitized patient, we discuss current methods to define sensitization, and assays to help identify clinically relevant anti-HLA antibodies. Desensitization strategies targeting all levels of the adaptive immune system are discussed with emphasis on novel techniques such as anti-CD 38 blockade and use of the Immunoglobulin G-Degrading Enzyme of Streptococcus Pyogenes. We next discuss donor procurement and the resurgence of donation after circulatory death as a viable strategy to significantly and safely increase the donor pool. Post-transplant, we evaluate non-invasive surveillance techniques including gene expression profiling and donor-derived cell-free DNA. Last, we discuss the ground-breaking developments in the field of xenotransplantation.

Impact of simultaneous heart procurement on outcomes of donation after circulatory death lung transplantation

Donation after circulatory death (DCD) heart procurement is done using either direct procurement (DP) or thoracoabdominal normothermic machine perfusion (TA-NRP). Both approaches could impact lung transplant outcomes with combined heart and lung procurements from the same donor. The impact of such practice on DCD lung transplant remains unstudied. We performed a retrospective analysis using the United Network for Organ Sharing (UNOS) dataset, identifying DCD lung transplants where the donor also donated the heart (cardia lung donor [CD]). A cohort of noncardiac DCD lung donors (noncardiac lung donor [NCD]) from the same era, matched for donor and recipient characteristics, was used as a comparison group. Both immediate and long-term outcomes were examined. A subanalysis was performed comparing the distinct impact of DP or TA-NRP on DCD lung transplant outcomes. Overall graft survival did not significantly differ between CD and NCD. However, recipients in the CD group trended toward a lower P/F ratio at 72 hours (CD vs NCD: 284 vs 3190; P = .054). In the subanalysis, we identified 40 DP donors and 22 TA-NRP donors. We found the both cohorts had lower P/F ratio at 72 hours than the NCD control (P = .04). Overall, 1-year graft survival was equivalent among the TA-NRP, DP, and NCD cohorts.

Impact of normothermic regional perfusion during DCD recovery on lung allograft function: A preclinical study

Background

Normothermic regional perfusion (NRP) has been growing as a novel procurement strategy after circulatory death (donation after circulatory death (DCD)) in the context of heart transplantation. However, the impact of NRP on lung graft viability is largely unknown. We sought to determine lung function after thoraco-abdominal NRP (TA-NRP) in a clinically relevant porcine DCD model.

Methods

Donor domestic pigs underwent hypoxic cardiac arrest to simulate DCD procurement and were randomly allocated to either 1-hour resuscitation on TA-NRP (n = 4) or direct lung procurement (direct procurement and perfusion (DPP), n = 4). All lungs were placed on ex-vivo lung perfusion (EVLP) and evaluated for 3 hours to assess functional outcome parameters and suitability for transplantation.

Results

After 1 hour of TA-NRP, cardiopulmonary bypass was weaned, and mean systemic PaO2/fraction of inspired oxygen was 418 ± 76 mm Hg, which was comparable to baseline (467 ± 41, p = 0.41). No significant differences were seen between the groups during EVLP, except for a higher pulmonary artery pressure in the TA-NRP group at 3 hours of EVLP (19.7 ± 1.5 vs 14.7 ± 2.1 mm Hg, p = 0.02). Perfusate inflammatory cytokines levels of IL-6 and IL-8 were higher at the first hour of EVLP in the TA-NRP group; however, these differences were not sustained as levels were similar by the last hour of EVLP. There were no differences in histology, cytokines, or metabolic profile of the TA-NRP lungs compared to DPP.

Conclusions

TA-NRP porcine lungs met functional criteria to proceed to transplantation and demonstrated no significant histological, cytokine, and metabolic differences when compared to DPP porcine lungs. This study highlights the value of considering TA-NRP lungs for transplant with well-established protocols.

Lung recovery utilizing thoracoabdominal normothermic regional perfusion during donation after circulatory death: The Colorado experience

Objective

Donation after circulatory death (DCD) procurement and transplantation after thoracoabdominal normothermic regional perfusion (TA-NRP) remains a novel technique to improve cardiac and hepatic allograft preservation but may be complicated by lung allograft pulmonary edema. We present a single-center series on early implementation of a lung-protective protocol with strategies to mitigate posttransplant pulmonary edema in DCD lung allografts after TA-NRP procurement.

Methods

Data from all lung transplantations performed using a TA-NRP procurement strategy from October 2022 to April 2023 are presented. Donor management consisted of key factors to reduce lung allograft pulmonary edema: aggressive predonation and early posttransplant diuresis, complete venous drainage at TA-NRP initiation, and early pulmonary artery venting upon initiation of systemic perfusion. Donor and recipient characteristics, procurement characteristics such as TA-NRP intervals, and 30-day postoperative outcomes were assessed.

Results

During the study period, 8 lung transplants were performed utilizing TA-NRP procurement from DCD donors. Donor ages ranged from 16 to 39 years and extubation time to declaration of death ranged from 10 to 90 minutes. Time from declaration to TA-NRP initiation was 7 to 17 minutes with TA-NRP perfusion times of 49 to 111 minutes. Median left and right allograft warm ischemia times were 55.5 minutes (interquartile range, 46.5-67.5 minutes) and 41.0 minutes (interquartile range, 39.0-53.0 minutes, respectively, with 2 recipients supported with cardiopulmonary bypass or venoarterial extracorporeal membrane oxygenation during implantation. No postoperative extracorporeal membrane oxygenation was required. There were no pulmonary-related deaths; however, 1 patient died from complications of severe necrotizing pancreatitis with a normal functioning allograft. All patients were extubated within 24 hours. Index intensive care unit length of stay ranged from 3 to 11 days with a hospital length of stay of 13 to 37 days.

Conclusions

Despite concern regarding quality of DCD lung allografts recovered using the TA-NRP technique, we report initial success using this procurement method. Implementation of strategies to mitigate pulmonary edema can result in acceptable outcomes following lung transplantation. Demonstration of short- and long-term safety and efficacy of this technique will become increasingly important as the use of TA-NRP for thoracic and abdominal allografts in DCD donors expands.