Thoracoabdominal normothermic regional perfusion in donors with neurological determination of death extends organ donors pool

BackgroundHeart transplantation team of the Heart Institute of the Ministry of Health of Ukraine performs thoracoabdominal normothermic regional perfusion (TA-NRP) procedure for organ preconditioning in marginal donors. Martial law in Ukraine worsens preexisting shortage of donor organs since February 2022. The use of TA-NRP has been shown to be effective in rescucitating organs in donors with circulatory determination of death (CDD), and we hypothesize that TA-NRP can be used to perform in situ organ perfusion in donors with neurological determination of death (NDD) as well, thereby improve organ quality.MethodsA single centre, retrospective analysis of outcomes after heart transplantation using organs from donors with NDD who underwent TA-NRP for preconditioning from 2022 to 2024 year at the Heart Institute Ministry of Health of Ukraine. The indications for TA-NRP were hemodynamic instability of donors with NDD, characterized by the need for norepinephrine >1.0 μg/kg/h to maintain mean blood pressure >50 mm Hg.ResultsTA-NRP for donor preconditioning was performed in 12 cases (11.3%) of 106 heart transplantations between 2019 and 2023. The average duration of TA-NRP was 124.5 ± 10.1 minutes. Prior to TA-NRP initiation, all donors exhibited metabolic acidosis, hyperkalemia, and hyperlactatemia. The implementation of TA-NRP normalized the acid-base balance, demonstrated by a significant increase in pH (p < .001), correction of base excess (BE) (p < .001), and an increase in bicarbonate levels (HCO3-) (p < .001). TA-NRP also significantly reduced baseline lactate levels from 10.4 ± 2.91 mmol/L to 1.57 ± 0.33 mmol/L (p < .001) and decreased potassium levels (p = .003). Additionally, it led to a significant reduction in donor heart rate (p = .001) and an increase in mean arterial pressure (p = .012), accompanied by a 6.6-fold reduction in donor norepinephrine requirements (p = .003).ConclusionThe use of TA-NRP in donors with NDD improved organ quality which resulted in 30 days survival rate of 83% and 1-year survival rate of 75% in organ recipients.

Clinical Outcomes of Machine Perfusion and Temperature Control Systems in Heart Transplantation: Where We Stand

Heart transplantation remains the preferred treatment for carefully selected patients with end-stage heart failure refractory to medical therapy. Advances in donor management, organ preservation, donor and recipient selection, immunosuppressive strategies, and mechanical circulatory support have significantly improved the safety and efficacy of heart transplantation. However, the persistent shortage of donor hearts and their limited preservation period continues to restrict access to this lifesaving procedure. The advent of innovative machine perfusion and temperature control systems for heart allograft preservation offers a promising avenue to address these challenges. These technologies aim to extend preservation times and enable the use of extended-criteria donors, thereby expanding the donor pool. In this review, we examine the outcomes from clinical trials, registry data, and single-center studies, utilizing the TransMedics Organ Care System Heart, Paragonix SherpaPak Cardiac Transport System, and XVIVO Heart Preservation System. As the field of heart transplantation evolves to accommodate longer ischemia times, expand organ sharing, and utilize donors previously considered marginal, the integration of these advanced technologies will be essential for optimizing post-transplant outcomes.

Single-center experience of extended brain-death donor heart preservation with the organ care system

BACKGROUND

The Organ Care System (OCS) (Transmedics, Andover, MA) reduces cold ischemic time of donor hearts by producing a normothermic beating state during ex vivo perfusion, enabling extended ex situ intervals, which potentially increases donor pool. We aimed to compare outcomes in utilization of OCS and conventional cold storage technique.

METHODS

Consecutive heart transplants following brain death at our institution between May 2022 and July 2023 were analyzed. Recipients were divided into those receiving hearts preserved with OCS [N = 15] and those with conventional cold storage (Control, N = 27), with OCS utilization when anticipated ischemic time was more than 4 h. Pre-transplant characteristics and transplant outcomes were compared.

RESULTS

OCS utilization allowed a significant increase in distance traveled for heart retrieval (OCS, 624 ± 269 vs. Control, 153 ± 128 miles, p < 0.001), with longer mean total preservation times (6.2 ± 1.1 vs 2.6 ± 0.6 h, p < 0.001). All but one patient displayed a general decrease or plateau in lactate throughout perfusion time by OCS. Both groups experienced similar rates of severe primary graft dysfunction (OCS, 6.7% [N = 1] vs. Control, 11.1% [N = 3], p = 0.63), with 100% in-hospital survival in the OCS group compared to 96.3% in the Control group (p = 0.34). Kaplan-Meier survival analysis showed that estimated one-year survival were comparable (OCS, 93.3 ± 6.4% vs. Control, 88.9 ± 6.0%, p = 0.61).

CONCLUSION

With a mean preservation time of around 6 h and distance covered of over 600 miles, our results using OCS indicate a potential to safely increase the quantity and viability of accessible organs, thus broadening the donor pool without negatively affecting outcomes.

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.

Ex vivo heart perfusion: an updated systematic review

Due to the discrepancy between patients awaiting a heart transplant and the availability of donor hearts, strategies to expand the donor pool and improve the transplant's success are crucial. This review aims to summarize current knowledge on the ex vivo heart preservation (EVHP) experience as an alternative to standard cold static storage (CSS). EVHP techniques can improve the preservation of the donor's heart before transplantation and allow for pre-transplant organ evaluation.

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.

Short-term outcomes after heart transplantation using donor hearts preserved with ex vivo perfusion

The standard Conventional Cold Storage (CCS) during heart transplantation procurement is associated with time-dependent ischemic injury to the graft, which is a significant independent risk factor for post-transplant early morbidity and mortality - especially when cold ischemic time exceeds four hours. Since 2018, Rigshospitalet (Copenhagen, Denmark) has been utilising ex vivo perfusion (Organ Care System, OCS) in selected cases. The objective of this study was to compare the short-term clinical outcomes of patients transplanted with OCS compared to CCS. Methods: This retrospective single-centre study was based on consecutive patients undergoing a heart transplant between January 2018 and April 2021. Patients were selected for the OCS group when the cold ischemic time was expected to exceed four hours. The primary outcome measure was six-month event-free survival. Results: In total, 48 patients were included in the study; nine were transplanted with an OCS heart. The two groups had no significant differences in baseline characteristics. Six-month event-free survival was 77.8% [95% CI: 54.9-100%] in the OCS group and 79.5% [95% CI: 67.8-93.2%] in the CCS group (p = 0.91). While the OCS group had a median out-of-body time that was 183 min longer (p < 0.0001), the cold ischemic time was reduced by 51 min (p = 0.007). Conclusion: In a Scandinavian setting, our data confirms that utilising OCS in heart procurement allows for a longer out-of-body time and a reduced cold ischemic time without negatively affecting safety or early post-transplant outcomes.

Heart Transplant and Donors After Circulatory Death: A Clinical-Preclinical Systematic Review

INTRODUCTION

Heart transplantation is the treatment of choice for end-stage heart failure. There is a mismatch between the number of donor hearts available and the number of patients awaiting transplantation. Expanding the donor pool is critically important. The use of hearts donated following circulatory death is one approach to increasing the number of available donor hearts.

MATERIALS AND METHODS

A systematic review was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines utilizing Pubmed/MEDLINE and Embase. Articles including adult human studies and preclinical animal studies of heart transplantation following donation after circulatory death were included. Studies of pediatric populations or including organs other than heart were excluded.

RESULTS

Clinical experience and preclinical studies are reviewed. Clinical experience with direct procurement, normothermic regional perfusion, and machine perfusion are included. Preclinical studies addressing organ function assessment and enhancement of performance of marginal organs through preischemic, procurement, preservation, and reperfusion maneuvers are included. Articles addressing the ethical considerations of thoracic transplantation following circulatory death are also reviewed.

CONCLUSIONS

Heart transplantation utilizing organs procured following circulatory death is a promising method to increase the donor pool and offer life-saving transplantation to patients on the waitlist living with end-stage heart failure. There is robust ongoing preclinical and clinical research to optimize this technique and improve organ yield. There are also ongoing ethical considerations that must be addressed by consensus before wide adoption of this approach.

Outcomes of liver transplantation with thoracoabdominal normothermic regional perfusion: a matched-controlled initial experience in Spain

Thoracoabdominal (TA) normothermic regional perfusion (NRP) should allow the safe recovery of heart and liver grafts simultaneously in the context of controlled donation after circulatory death (cDCD). We present the initial results of cDCD liver transplantation with simultaneous liver and heart procurement in Spain until October 2021. Outcomes were compared with a matched cohort of cDCD with abdominal NRP (A-NRP) from participating institutions. Primary endpoints comprised early allograft dysfunction (EAD) or primary non-function (PNF), and the development of ischemic-type biliary lesions (ITBL). Six transplants were performed using cDCD with TA-NRP during the study period. Donors were significantly younger in the TA-NRP group than in the A-NRP group (median 45.6 years and 62.9 years respectively, p = 0.011), with a median functional warm ischemia time of 12.5 min in the study group and 13 min in the control group. Patient characteristics, procurement times, and surgical baseline characteristics did not differ significantly between groups. No patient in the study group developed EAD or PNF, and over a median follow-up of 9.8 months, none developed ITBL or graft loss. Extending A-NRP to TA-NRP for cardiac procurement may be technically challenging, but it is both feasible and safe, showing comparable postoperative outcomes to A-NRP.

Graft preservation in heart transplantation: current approaches

Heart transplantation (HTx) represents the current best surgical treatment for patients affected by end-stage heart failure. However, with the improvement of medical and interventional therapies, the population of HTx candidates is increasingly old and at high-risk for mortality and complications. Moreover, the use of "extended donor criteria" to deal with the shortage of donors could increase the risk of worse outcomes after HTx. In this setting, the strategy of donor organ preservation could significantly affect HTx results. The most widely used technique for donor organ preservation is static cold storage in ice. New techniques that are clinically being used for donor heart preservation include static controlled hypothermia and machine perfusion (MP) systems. Controlled hypothermia allows for a monitored cold storage between 4°C and 8°C. This simple technique seems to better preserve the donor heart when compared to ice, probably avoiding tissue injury due to sub-zero °C temperatures. MP platforms are divided in normothermic and hypothermic, and continuously perfuse the donor heart, reducing ischemic time, a well-known independent risk factor for mortality after HTx. Also, normothermic MP permits to evaluate marginal donor grafts, and could represent a safe and effective technique to expand the available donor pool. However, despite the increasing number of donor hearts preserved with these new approaches, whether these techniques could be considered superior to traditional CS still represents a matter of debate. The aim of this review is to summarize and critically assess the available clinical data on donor heart preservation strategies employed for HTx.

Transesophageal Echocardiography Guidance to Prevent and Manage Pitfalls from Abdominal Normothermic Regional Perfusion and Optimize Timing during Organ Retrieval from a Donor after Circulatory Death

An essential means of collecting more abdominal donor organs is controlled donation after circulatory death (cDCD). The organs are typically preserved during cDCD using the abdominal normothermic regional perfusion (A-NRP) technique to recirculate oxygenated blood flow following cardiac arrest and the withdrawal of life support. One of the challenges of A-NRP is ensuring the correct vascular devices' positionings, specifically extracorporeal membrane oxygenation cannulae and aortic balloons, typically achieved through fluoroscopy with or without contrast agents. Here, we present a case report in which transesophageal echocardiography (TEE) helped the transplant team to effectively procure viable abdominal organs from a cDCD donor in the shortest time frame, as minimizing time is one of the most crucial factors in maintaining organ viability. TEE use leads to a more effective and efficient A-NRP procedure with limited complications. In addition, it allows us to observe the circulation of both the thoracic and part of the abdominal organs using one fast exam. This case is the first report describing TEE as a primary guide and useful tool for DCD donors. However, prospective studies are needed to confirm that TEE could be used as standard practice during all DCD organ retrieval procedures.

Breaking barriers in cardiac donation after circulatory death

BACKGROUND

Heart transplant (HT) from controlled donation after circulatory death (cDCD) is an emerging strategy that is rapidly expanding and may help increase the heart donor pool.

MATERIALS AND METHODS

The use of thoracoabdominal normothermic regional perfusion with extracorporeal membrane oxygenation device has allowed to perform HT after cDCD in our country. We present a successful case of heart transplantation using a graft from cDCD with 201 min cold ischemia time.

DISCUSSION AND CONCLUSION

HT from cDCD could be a good alternative to brain dead donation. This experience suggests than nonlocal cardiac from cDCD could tolerate long periods of cold ischemia time and break the main barriers with this technique.

Modulation of Mitochondrial Respiration During Early Reperfusion Reduces Cardiac Injury in Donation After Circulatory Death Hearts

ABSTRACT

Donation after circulatory death (DCD) donors are a potential source for heart transplantation. The DCD process has unavoidable ischemia and reperfusion (I/R) injury, primarily mediated through mitochondria, which limits routine utilization of hearts for transplantation. Amobarbital (AMO), a transient inhibitor of the electron transport chain, is known to decrease cardiac injury following ex vivo I/R. We studied whether AMO treatment during reperfusion can decrease injury in DCD hearts. Sprague Dawley rat hearts subjected to 25 minutes of in vivo ischemia (DCD hearts), or control beating donor hearts, were treated with AMO or vehicle for the first 5 minutes of reperfusion, followed by Krebs-Henseleit buffer reperfusion for 55 minutes (for mitochondrial isolation) or 85 minutes (for infarct size determination). Compared with vehicle, AMO treatment led to decreased infarct size (25.2% ± 1.5% vs. 31.5% ± 1.5%; P ≤ 0.05) and troponin I release (4.5 ± 0.05 ng/mL vs. 9.3 ± 0.24 ng/mL, P ≤ 0.05). AMO treatment decreased H 2 O 2 generation with glutamate as complex I substrate in both subsarcolemmal mitochondria (SSM) (37 ± 3.7 pmol·mg -1 ·min -1 vs. 56.9 ± 4.1 pmol·mg -1 ·min -1 ; P ≤ 0.05), and interfibrillar mitochondria (IFM) (31.8 ± 2.8 pmol·mg -1 ·min -1 vs. 46 ± 4.8 pmol·mg -1 ·min -1 ; P ≤ 0.05) and improved calcium retention capacity in SSM (360 ±17.2 nmol/mg vs. 277 ± 13 nmol/mg; P ≤ 0.05), and IFM (483 ± 20 nmol/mg vs. 377± 19 nmol/mg; P ≤ 0.05) compared with vehicle treatment. SSM and IFM retained more cytochrome c with AMO treatment compared with vehicle. In conclusion, brief inhibition of mitochondrial respiration during reperfusion using amobarbital is a promising approach to decrease injury in DCD hearts.

Normothermic Regional Perfusion is an Emerging Cost-Effective Alternative in Donation After Circulatory Death (DCD) in Heart Transplantation

In donation after circulatory death (DCD) organ transplantation, normothermic regional perfusion (NRP) restores oxygenated blood flow following cardiac arrest and reverses warm ischemia. Recently, NRP has also been used to help recover DCD hearts in addition to the abdominal organs. While DCD donation has increased the number of abdominal organs and lungs pool, it has not been able to increase the number of heart transplants, despite the fact that it has the potential to increase the number of heart transplants by 15-30%. Thoracoabdominal normothermic regional perfusion makes heart transplantation feasible and permits assessing heart function before an organ procurement without affecting the preservation of abdominal organs. NRP can be used in two ways for DCD donor heart transplants: normothermic regional perfusion followed by machine perfusion (NRP-MP) and normothermic regional perfusion followed by static cold storage (NRP-SCS). Normothermic regional perfusion is an emerging technology, a cost-effective alternative in donation after circulatory death (DCD), and will increase the pool of donors in heart transplantation.

Normothermic Ex Situ Heart Perfusion With the Organ Care System for Cardiac Transplantation: A Meta-analysis

BACKGROUND

Heart transplantation (HTx) is, at present, the most effective therapy for end-stage heart failure patients; however, the number of patients on the waiting list is rising globally, further increasing the gap between demand and supply of donors for HTx. First studies using the Organ Care System (OCS) for normothermic machine perfusion show promising results yet are limited in sample size. This article presents a meta-analysis of heart donation either after brain death (OCS-DBD) or circulatory death (OCS-DCD) on using OCS versus static cold storage used for HTx.

METHODS

A systematic literature search was performed for articles discussing the use of normothermic ex situ heart perfusion in adult patients. Thirty-day survival outcomes were pooled, and odds ratios were calculated using random-effects models. Long-term survival was visualized with Kaplan-Meier curves, hazard ratios were calculated and pooled using fixed-effects models, and secondary outcomes were analyzed.

RESULTS

A total of 12 studies were included, with 741 patients undergoing HTx, of which 260 with the OCS (173 DBD and 87 DCD). No differences were found between the 3 groups for early and late survival outcomes or for secondary outcomes.

CONCLUSIONS

OCS outcomes, for both DBD and DCD hearts, appeared similar as for static cold storage. Therefore, OCS is a safe and effective technique to enlarge the cardiac donor pool in both DBD and DCD, with additional benefits for long-distance transport and surgically complex procedures.

Machine Perfusion for Human Heart Preservation: A Systematic Review

Currently, static cold storage (SCS) of hearts from donations after brainstem death remains the standard clinically. However, machine perfusion (MP) is considered an approach for donor organ management to extend the donor pool and/or increase the utilization rate. This review summarizes and critically assesses the available clinical data on MP in heart transplantation. We searched Medline (PubMed), Cochrane, Embase, and clinicaltrials.gov, along with reference lists of the included publications and identified 40 publications, including 18 articles, 17 conference abstracts, and five ongoing clinical trials. Two types of MP were used: hypothermic MP (HMP) and normothermic MP (NMP). Three studies evaluated HMP, and 32 evaluated NMP. Independent of the system, MP resulted in clinical outcomes comparable to traditional SCS. However, NMP seemed especially beneficial for high-risk cases and donation after circulatory death (DCD) hearts. Based on currently available data, MP is non-inferior to standard SCS. Additionally, single-centre studies suggest that NMP could preserve the hearts from donors outside standard acceptability criteria and DCD hearts with comparable results to SCS. Finally, HMP is theoretically safer and simpler to use than NMP. If a machine malfunction or user error occurs, NMP, which perfuses a beating heart, would have a narrower margin of safety. However, further well-designed studies need to be conducted to draw clear conclusions.

Ex-Vivo Preservation with the Organ Care System in High Risk Heart Transplantation

Objective: Ex vivo organ perfusion is an advanced preservation technique that allows graft assessment and extended ex situ intervals. We hypothesized that its properties might be especially beneficial for high-risk recipients and/or donors with extended criteria. Methods: We reviewed the outcomes of 119 consecutive heart transplant patients, which were divided into two groups: A (OCS) vs. B (conventional). Ex vivo organ perfusion was performed using the Organ Care System (OCS). Indications for OCS-usage were expected ischemic time of >4 h or >2 h plus given extended donor criteria. Results: Both groups included mostly redo cases (A: 89.7% vs. B: 78.4%; p = 0.121). Incidences of donors with previous cardiac arrest (%) (A: 32.4 vs. B: 22.2; p < 0.05) or LV-hypertrophy (%) (A: 19.1 vs. B: 8.3; p = 0.119) were also increased in Group A. Ex situ time (min) was significantly longer in Group A (A: 381 (74) vs. B: 228 (43); p < 0.05). Ventilation time (days) (A: 10.0 (19.9) vs. B: 24.3 (43.2); p = 0.057), postoperative need for ECLS (%) (A: 25.0 vs. B: 39.2; p = 0.112) and postoperative dialysis (chronic) (%) (A: 4.4 vs. B: 27.5; p < 0.001) were numerically better in the OCS group, without any difference in the occurrence of early graft rejection. The 30-d-survival (A: 92.4% vs. B: 90.2%; p = 0.745) and mid-term survival were statistically not different between both groups. Conclusions: OCS heart allowed safe transplantation of surgically complex recipients with excellent one-year outcomes, despite long preservation times and unfavourable donor characteristics. Furthermore, we observed trends towards decreased ventilation times and fewer ECLS treatments. In times of reduced organ availability and increasing recipient complexity, OCS heart is a valuable instrument that enables otherwise infeasible allocations and contributes to increase surgical safety.

Role of normothermic perfusion with ECMO in donation after controlled cardiac death in Spain

Spain has become one of the most active countries in donation after controlled cardiac death, using normothermic abdominal perfusion with ECMO in more than 50% of all donors - a situation contributed to by the creation of mobile teams to support hospitals lacking this technology. The donation process must be respectful of the wishes and values of the patients and their relatives, especially if there is pre mortem manipulation, and the absence of cerebral perfusion should be guaranteed. The liver is the most benefited organ by reducing biliary complications as well as the loss of grafts. In renal transplantation, the technique could contribute to reduce the incidence of delayed graft function. In addition, the procedure is compatible with surgical rapid recovery in hypothermia when there is also lung donation. The future lies in the consolidation of cardiac donation by extending normothermic perfusion to the thoracic cavity.

Ex vivo normothermic perfusion in heart transplantation: a review of the TransMedics® Organ Care System

Cardiac transplantation is the gold standard for treatment for select patients with end-stage heart failure, yet donor supply is limited. Ex vivo machine perfusion is an emerging technology capable of safely preserving organs and expanding the viable donor pool. The TransMedics^® Organ Care System™ is an investigational device which mimics physiologic conditions while maintaining the heart in a warm, beating state rather than cold storage. The use of Organ Care System allows increased opportunities for using organs from marginal donors, distant procurement sites, donation after cardiac death, and in recipients with complex anatomy. In the future, bioengineering technologies including use of mesenchymal stem cells, viral vector delivery of gene therapy, and alternate devices may further broaden the field of ex vivo machine perfusion.

Early US experience with cardiac donation after circulatory death (DCD) using normothermic regional perfusion

BACKGROUND

Given the shortage of suitable donor hearts for cardiac transplantation and the growing interest in donation after circulatory death (DCD), our institution recently began procuring cardiac allografts from DCD donors.

METHODS

Between October 2020 and March 2021, 15 patients with heart failure underwent cardiac transplantation using DCD allografts. Allografts were procured using a modified extracorporeal membrane oxygenation circuit for thoracic normothermic regional perfusion (TA-NRP) and were subsequently transported using cold static storage. Data collection and analysis were performed with institutional review board approval.

RESULTS

The mean age of the DCD donors was 23 ± 7 years and average time on TA-NRP was 56 ± 8 minutes. Total ischemic time was 183 ± 31 minutes and distance from transplant center was 373 ± 203 nautical miles. Recipient age was 55 ± 14 years, with 8 (55.3%) recipients on durable left ventricular assist device support. Post-transplant, 6 (40%) recipients experienced mild left ventricle primary graft dysfunction (PGD-LV), 3 (20%) recipients experienced moderate PGD-LV, and no recipients experienced severe PGD-LV. Postoperative transthoracic echocardiogram demonstrated left ventricular ejection fraction >55% in all recipients. One recipient (6.6%) developed International Society for Heart and Lung Transplantation 2R acute cellular rejection on first biopsy. At last follow-up, all 15 recipients were alive past 30-days.

CONCLUSIONS

Cardiac DCD provides an opportunity to increase the availability of donor hearts for transplantation. Utilizing TA-NRP with cold static storage, we have extended the cold ischemic time of DCD allografts to almost 3 hours, allowing for inter-hospital organ transport.

Heart Donation From Donors After Controlled Circulatory Death

The gold-standard therapy for advanced-stage heart failure is cardiac transplantation. Since the first heart transplant in 1967, the majority of hearts transplanted came from brain death donors. Nevertheless, in recent years, the option of donation after circulatory death (DCD) is gaining importance to increase donor pool. Currently, heart-transplant programs using controlled donation after circulatory death (cDCD) have been implemented in the United Kingdom, Belgium, Australia, United States of America, and, recently, in Spain. In this article, we performed a concise review of the literature in heart cDCD; we summarize the pathophysiology involved in ischemia and reperfusion injury during this process, the different techniques of heart retrieval in cDCD donors, and the strategies that can be used to minimize the damage during retrieval and until transplantation. Heart transplant using DCD hearts is in continuous improvement and must be implemented in experienced cardiac transplant centers.

Spanish experience with heart transplants from controlled donation after the circulatory determination of death using thoraco-abdominal normothermic regional perfusion and cold storage

Heart transplantation from controlled donation after the circulatory determination of death (cDCDD) may help to increase the availability of hearts for transplantation. During 2020, four heart transplants were performed at three different Spanish hospitals based on the use of thoraco-abdominal normothermic regional perfusion (TA-NRP) followed by cold storage (CS). All donors were young adults <45 years. The functional warms ischemic time ranged from 8 to 16 minutes. In all cases, the heart recovered sinus rhythm within 1 minute of TA-NRP. TA-NRP was weaned off or decreased <1L within 25 minutes. No recipient required mechanical support after transplantation and all were immediately extubated and discharged home (median hospital stay: 21 days) with an excellent outcome. Four livers, eight kidneys, and two pancreata were also recovered and transplanted. All abdominal grafts recipients experienced an excellent outcome. The use of TA-NRP makes heart transplantation feasible and allows assessing heart function before organ procurement without any negative impact on the preservation of abdominal organs. The use of TA-NRP in cDCDD heart donors in conjunction with cold storage following retrieval can eliminate the need to use ex situ machine perfusion devices, making cDCDD heart transplantation economically possible in other countries.

Transplantation of donor hearts after circulatory death using normothermic regional perfusion and cold storage preservation

OBJECTIVES

Hearts donated after circulatory determination of death are usually preserved with normothermic machine perfusion prior to transplantation. This type of preservation is costly, requires bench time adding to warm ischaemia, and does not provide a reliable evaluation of the unloaded donor heart. We report on 4 successful donation after circulatory death (category III) hearts transplanted after thoraco-abdominal normothermic regional perfusion (NRP) and static cold storage.

METHODS

After life sustaining therapy was withdrawn and death was declared, perfusion to thoraco-abdominal organs was restored using extracorporeal circulation via cannulas in the femoral artery and vein and clamping of supra-aortic vessels. After weaning from extracorporeal circulation, cardiac function was assessed. Once approved, the heart was retrieved and stored using classic static cold storage. Data are expressed as median [min-max].

RESULTS

Donor and recipient ages were 44 years [12-60] (n = 4) and 53 years [14-64] (n = 4), respectively. Time from the withdrawal of life sustaining therapy to start of NRP was 22 min [18-31]. Cold storage time was 72 min [35-129]. Thirty-day survival was 100% with a left ventricle ejection fraction of 60% [50-60].

CONCLUSIONS

Donation after circulatory death heart transplantation using thoraco-abdominal NRP and subsequent cold storage preservation for up to 129 min was safe for 4 procedures and could be a way to expand the donor heart pool while avoiding costs of machine preservation.

Assessment of the right ventricle in donation after circulatory death hearts

In donation after circulatory death heart transplantation, the donor heart is exposed to circulatory load. The right ventricle, due to its structure, has high compliance for volume load but is particularly vulnerable to increased pressure load. This study used a porcine model to conduct a functional assessment of the hemodynamics of the heart, with a focus on the right ventricle. Six pigs weighing 24.6 ± 1.4 kg were used. Circulatory death was induced by asphyxiation after median sternotomy. After 30 minutes in the state of global warm ischemia, the ascending aorta was clamped, followed by a 20-minute reperfusion of the heart with a 20°C blood cardioplegia solution. Systemic circulation was established by cardiopulmonary bypass after aortic cross-clamping. After initial reperfusion, the blood cardioplegia solution was replaced with blood. The blood was then rewarmed while the heart was still in a non-working state. Cardiac function was assessed twice in situ, first by the thermodilution method, and then, by the pressure-volume measurement both at preischemia and at three hours after initiation of reperfusion. The recovery rate of cardiac output was 75%. End-systolic elastance (P = .02) and pulmonary arterial elastance significantly increased (P = .03), but the ratio of arterial elastance to end-systolic elastance was preserved (P = .91) in the right ventricle. Despite a decrease in cardiac output after reperfusion from warm ischemia, the right ventricle had a potential to respond the elevated afterload. It is important that donations after circulatory death heart transplantation should be performed with attention to avoiding right ventricular distension.

DCD donations and outcomes of heart transplantation: the Australian experience

Purpose

There is increasing clinical utilization of hearts from the donation after circulatory death (DCD) pathway with the aim of expanding the donor pool and mitigating the ever-present discrepancy between the inadequate availability of good quality donor hearts and the rising number of patients with end-stage heart failure.

Methods

This article reviews the rationale, practice, logistical factors, and 5-year experience of DCD heart transplantation at St Vincent's Hospital, Sydney.

Findings

Between July 2014 and July 2019, 69 DCD donor retrievals were undertaken resulting in 49 hearts being instrumented on an ex situ normothermic cardiac perfusion device. Seventeen (35%) of these hearts were declined and the remaining 32 (65%) were used for orthotopic DCD heart transplantation. At 5 years of follow-up, the 1-, 3-, and 5-year survival was 96%, 94%, and 94% for DCD hearts compared with 89%, 83%, and 82% respectively for donation after brain death (DBD) hearts (n.s). The immediate post-implant requirement for temporary extra-corporeal membrane oxygenation (ECMO) support for delayed graft function was 31% with no difference in rejection rates when compared with the contemporaneous cohort of patients transplanted with standard criteria DBD hearts.

Summary

DCD heart transplantation has become routine and incorporated into standard clinical practice by a handful of pioneering clinical transplant centres. The Australian experience demonstrates that excellent medium-term outcomes are achievable from the use of DCD hearts. These outcomes are consistent across the other centres and consequently favour a more rapid and wider uptake of heart transplantation using DCD donor hearts, which would otherwise be discarded.

Short-Term Graft Failure of Organs Procured from Drug-Related Deaths Compared with Other Causes of Death

BACKGROUND

A gap exists between the number of patients on the national organ transplant waiting list and the number of transplants performed. Victims of drug and overdose-related death are increasingly utilized as organ donors. We sought to evaluate the suitability of organs from drug and overdose-related death for organ transplantation. This study compares the proportion of short-term allograft failure of organs procured from patients with drug-related deaths with those without drug-related deaths.

METHODS

Organ donations after drug-related deaths (DDD) were compared with organ donations from non-drug-related donations after brain deaths (DBD) and donations after circulatory deaths (DCD) utilizing the Gift of Hope Organ & Tissue Donor Network for a total of 15 months.

RESULTS

Eighty-one donors were identified from each of the DDD, DBD, and DCD groups with 264, 234, and 181 organs transplanted, respectively. The proportions of short-term graft failures were 1.15% in the DDD group compared with 2.14% in the DBD group (p = NS) and 5.52% in the DCD group (p = 0.01). The US Public Health Service increased-risk features for transmission of infectious diseases were present in 70.3% of the DDD cases. Donors from the DDD group were younger on average than those in other groups (33 to 42 years).

CONCLUSIONS

The proportion of graft failures in the drug-related deaths (DDD) group was equal to or less than those from other causes of death on short-term follow-up. Drug-related death does not appear to be a contraindication for organ procurement despite increased risk features for infectious disease transmission.

Role of normothermic perfusión with ECMO in donation after controlled cardiac death in Spain

Spain has become one of the most active countries in donation after controlled cardiac death, using normothermic abdominal perfusion with ECMO in more than 50% of all donors - a situation contributed to by the creation of mobile teams to support hospitals lacking this technology. The donation process must be respectful of the wishes and values of the patients and their relatives, especially if there is pre mortem manipulation, and the absence of cerebral perfusion should be guaranteed. The liver is the most benefited organ by reducing biliary complications as well as the loss of grafts. In renal transplantation, the technique could contribute to reduce the incidence of delayed graft function. In addition, the procedure is compatible with surgical rapid recovery in hypothermia when there is also lung donation. The future lies in the consolidation of cardiac donation by extending normothermic perfusion to the thoracic cavity.

The rise of organ donation after circulatory death: a narrative review

Solid organ transplantation saves and transforms lives. The original type of organ donation from deceased patients was controlled donation after circulatory death, previously referred to as non-heart beating organ donation. The rise of donation after circulatory death in the UK came about through advances in critical care and transplant medicine and support from several key organisations in developing a robust ethical, legal and professional framework. The transplant waiting list reached a historic peak in 2009-2010 of 8000 patients, but fell by 25% to 6000 in 2017-2018. There has also been a steady rise in the number of deceased donors and the number of donations after circulatory death. The contribution of donation after circulatory death to the total number of donations rose steadily between 2000 and 2012 and has remained about 40% since. Although the situation has improved for patients waiting for a transplant, deaths and long waits remain common. Changes to legislative, technical and peri-mortem procedures may greatly change future practices in donation after circulatory death in the UK.

Heart transplantation from donation after circulatory death donors: Present and future

The first successful human heart transplantation was reported on 3 December 1967, by Christiaan Barnard in South Africa. Since then this life-saving procedure has been performed in over 120 000 patients. A limitation to the performance of this procedure is the availability of donor hearts with as many as 20% of patients dying before a donor's heart is available for transplant. Today, hearts for transplantation are procured from individuals experiencing donation after brain death (DBD). Interestingly, this, however, was not always the case as the first heart transplants occurred after circulatory death. Revisiting the availability of hearts for transplant from those experiencing donation after circulatory death (DCD) could further expand the number of hearts suitable for transplantation. There are several considerations pertinent to transplanting hearts from those undergoing circulatory death. In this review, we summarize the main distinctions between DBD and DCD heart donation and discuss the research relevant to increasing the number of hearts available for transplantation by including individual's hearts that experience circulatory death.