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.

Advances in lung transplantation: 60 years on

Lung transplantation is a well-established treatment for advanced lung disease, improving survival and quality of life. Over the last 60 years all aspects of lung transplantation have evolved significantly and exponential growth in transplant volume. This has been particularly evident over the last decade with a substantial increase in lung transplant numbers as a result of innovations in donor utilization procurement, including the use donation after circulatory death and ex-vivo lung perfusion organs. Donor lungs have proved to be surprisingly robust, and therefore the donor pool is actually larger than previously thought. Parallel to this, lung transplant outcomes have continued to improve with improved acute management as well as microbiological and immunological insights and innovations. The management of lung transplant recipients continues to be complex and heavily dependent on a tertiary care multidisciplinary paradigm. Whilst long term outcomes continue to be limited by chronic lung allograft dysfunction improvements in diagnostics, mechanistic understanding and evolutions in treatment paradigms have all contributed to a median survival that in some centres approaches 10 years. As ongoing studies build on developing novel approaches to diagnosis and treatment of transplant complications and improvements in donor utilization more individuals will have the opportunity to benefit from lung transplantation. As has always been the case, early referral for transplant consideration is important to achieve best results.

Patient's last wish: organ donation after euthanasia. What conditions should be met to fulfill it?

Abstract

Organ donation after euthanasia (ODE) is a complex procedure involving the patient, the family, and the medical staff. Most organ donations occur from patients declared brain dead, and healthcare professionals rely on surrogate decisions, or the possible expression of ante-mortem will. Organ donation from deceased individuals is thus feasible under rigorous conditions, while direct donation after euthana-sia is not possible. The scientific community has not reached a shared conclusion. It is also difficult to quantify the number of patients who would be medically eligible to donate organs after euthanasia. In keep-ing with the core the principle of self-determination, any decision to undergo euthanasia (with or without organ donation) must be voluntary and not influenced by external pressures. For this reason, the physician should avoid informing the patient about the possibility of donating their organs before their request for euthanasia is evaluated. Just as noteworthy is the issue of healthcare providers' conscientious objec-tion and the receiving patient's right to know whether the transplanted organs come from a subject who underwent euthanasia. Finally, the patient who requests to end their life does so primarily because they are tormented by unbearable suffering and often expresses, as a last wish, the desire to exercise their free will regarding their own body. Organ donation after euthanasia would therefore seem to reinforce patient autonomy and self-esteem, thus giving a different meaning to their inevitable death, which is useful in saving the lives of others.

Donation after circulatory death improves probability of heart transplantation in waitlisted candidates and results in post-transplant outcomes similar to those achieved with brain-dead donors

OBJECTIVE

To quantitate the impact of heart donation after circulatory death (DCD) donor utilization on both waitlist and post-transplant outcomes in the United States.

METHODS

The United Network for Organ Sharing database was queried to identify all adult waitlisted and transplanted candidates between October 18, 2018, and December 31, 2022. Waitlisted candidates were stratified according to whether they had been approved for donation after brain death (DBD) offers only or also approved for DCD offers. The cumulative incidence of transplantation was compared between the 2 cohorts. In a post-transplant analysis, 1-year post-transplant survival was compared between unmatched and propensity-score-matched cohorts of DBD and DCD recipients.

RESULTS

A total of 14,803 candidates were waitlisted, including 12,287 approved for DBD donors only and 2516 approved for DCD donors. Overall, DCD approval was associated with an increased sub-hazard ratio (HR) for transplantation and a lower sub-HR for delisting owing to death/deterioration after risk adjustment. In a subgroup analysis, candidates with blood type B and status 4 designation received the greatest benefit from DCD approval. A total of 12,238 recipients underwent transplantation, 11,636 with DBD hearts and 602 with DCD hearts. Median waitlist times were significantly shorter for status 3 and status 4 recipients receiving DCD hearts. One-year post-transplant survival was comparable between unmatched and propensity score-matched cohorts of DBD and DCD recipients.

CONCLUSIONS

The use of DCD hearts confers a higher probability of transplantation and a lower incidence of death/deterioration while on the waitlist, particularly among certain subpopulations such as status 4 candidates. Importantly, the use of DCD donors results in similar post-transplant survival as DBD donors.

Can we safely expand the donation after circulatory death donor heart pool by extending the donor age limit?

OBJECTIVE

This study evaluates the impact of donor age on outcomes following donation after circulatory death heart transplantation.

METHODS

The United Network for Organ Sharing registry was queried to analyze adult recipients who underwent isolated donation after circulatory heart transplantation from January 1, 2019, to September 30, 2023. The cohort was stratified into 2 groups according to donor age, where advanced donor age was defined as 40 years or more. Outcomes were 90-day and 1-year post-transplant survival. Propensity score matching was performed. Subgroup analysis was performed to evaluate the effects of recipient age on 90-day survival among the recipients with advanced-age donors.

RESULTS

A total of 994 recipients were included in the study period, and 161 patients (17.1%) received allografts from advanced-age donors. During the study period, the annual incidence of donation after circulatory heart transplantation with advanced-age donors substantially increased. The recipients with advanced-age donors had similar 90-day and 1-year post-transplant survivals compared with the recipients with younger donors. The comparable 90-day survival persisted in a propensity score-matched comparison. In the subgroup analysis among the recipients with advanced-age donors, the recipients aged 60 years or more had significantly reduced 90-day survival compared with the recipients aged less than 60 years.

CONCLUSIONS

The use of appropriately selected donation after circulatory donors aged 40 years or more has similar survival compared with that of younger donors. With careful candidate risk stratification and selection, consideration of using donation after circulatory donors aged more than 40 years may further ameliorate ongoing organ shortage with comparable early post-transplant outcomes.

Hypothermic Oxygenated Perfusion Improves Vascular and Contractile Function by Preserving Endothelial Nitric Oxide Production in Cardiac Grafts Obtained With Donation After Circulatory Death

BACKGROUND

Cardiac donation after circulatory death is a promising option to increase graft availability. Graft preservation with 30 minutes of hypothermic oxygenated perfusion (HOPE) before normothermic machine perfusion may improve cardiac recovery as compared with cold static storage, the current clinical standard. We investigated the role of preserved nitric oxide synthase activity during HOPE on its beneficial effects.

METHODS AND RESULTS

Using a rat model of donation after circulatory death, hearts underwent in situ ischemia (21 minutes), were explanted for a cold storage period (30 minutes), and then reperfused under normothermic conditions (60 minutes) with left ventricular loading. Three cold storage conditions were compared: cold static storage, HOPE, and HOPE with Nω-nitro-L-arginine methyl ester (nitric oxide synthase inhibitor). To evaluate potential confounding effects of high coronary flow during early reperfusion in HOPE hearts, bradykinin was administered to normalize coronary flow to HOPE levels in 2 additional groups (cold static storage and HOPE with Nω-nitro-L-arginine methyl ester). Cardiac recovery was significantly improved in HOPE versus cold static storage hearts, as determined by cardiac output, left ventricular work, contraction and relaxation rates, and coronary flow (P<0.05). Furthermore, HOPE attenuated postreperfusion calcium overload. Strikingly, the addition of Nω-nitro-L-arginine methyl ester during HOPE largely abolished its beneficial effects, even when early reperfusion coronary flow was normalized to HOPE levels.

CONCLUSIONS

HOPE provides superior preservation of ventricular and vascular function compared with the current clinical standard. Importantly, HOPE's beneficial effects require preservation of nitric oxide synthase activity during the cold storage. Therefore, the application of HOPE before normothermic machine perfusion is a promising approach to optimize graft recovery in donation after circulatory death cardiac grafts.

Effects of Trehalose Preconditioning on H9C2 Cell Viability and Autophagy Activation in a Model of Donation after Circulatory Death for Heart Transplantation

Donation after circulatory death (DCD) is a promising strategy for alleviating donor shortage in heart transplantation. Trehalose, an autophagy inducer, has been shown to be cardioprotective in an ischemia-reperfusion (IR) model; however, its role in IR injury in DCD remains unknown. In the present study, we evaluated the effects of trehalose on cardiomyocyte viability and autophagy activation in a DCD model. In the DCD model, cardiomyocytes (H9C2) were exposed to 1 h warm ischemia, 1 h cold ischemia, and 1 h reperfusion. Trehalose was administered before cold ischemia (preconditioning), during cold ischemia, or during reperfusion. Cell viability was measured using the Cell Counting Kit-8 after treatment with trehalose. Autophagy activation was evaluated by measuring autophagy flux using an autophagy inhibitor, chloroquine, and microtubule-associated protein 1A/1B light chain 3 B (LC3)-II by western blotting. Trehalose administered before the ischemic period (trehalose preconditioning) increased cell viability. The protective effects of trehalose preconditioning on cell viability were negated by chloroquine treatment. Furthermore, trehalose preconditioning increased autophagy flux. Trehalose preconditioning increased cardiomyocyte viability through the activation of autophagy in a DCD model, which could be a promising strategy for the prevention of cardiomyocyte damage in DCD transplantation.

Erratum: Advantages and limitations of clinical scores for donation after circulatory death liver transplantation

[This corrects the article DOI: 10.3389/fsurg.2021.808733.].

Metabolic Considerations in Direct Procurement and Perfusion Protocols with DCD Heart Transplantation

Heart transplantation with donation after circulatory death (DCD) provides excellent patient outcomes and increases donor heart availability. However, unlike conventional grafts obtained through donation after brain death, DCD cardiac grafts are not only exposed to warm, unprotected ischemia, but also to a potentially damaging pre-ischemic phase after withdrawal of life-sustaining therapy (WLST). In this review, we aim to bring together knowledge about changes in cardiac energy metabolism and its regulation that occur in DCD donors during WLST, circulatory arrest, and following the onset of warm ischemia. Acute metabolic, hemodynamic, and biochemical changes in the DCD donor expose hearts to high circulating catecholamines, hypoxia, and warm ischemia, all of which can negatively impact the heart. Further metabolic changes and cellular damage occur with reperfusion. The altered energy substrate availability prior to organ procurement likely plays an important role in graft quality and post-ischemic cardiac recovery. These aspects should, therefore, be considered in clinical protocols, as well as in pre-clinical DCD models. Notably, interventions prior to graft procurement are limited for ethical reasons in DCD donors; thus, it is important to understand these mechanisms to optimize conditions during initial reperfusion in concert with graft evaluation and re-evaluation for the purpose of tailoring and adjusting therapies and ensuring optimal graft quality for transplantation.

A modified intraventricular balloon method for functional assessment of hearts from donation after circulatory death

Objective

Functional assessment of hearts during ex-vivo heart perfusion is not well-established. Conventional intraventricular balloon methods for large animals sacrifice the mitral valve. This study assessed the effectiveness of the modified intraventricular balloon method in comparison with other modalities used during working mode in juvenile pigs.

Methods

Following asphyxia circulatory arrest, hearts were ischemic for 15 minutes and then reperfused on an ex-vivo device for 2 hours before switching to working mode. Left ventricular pressure was continuously measured during reperfusion by a saline-filled balloon fixated in the left atrium. Spearman Correlation Coefficients with linear regression lines with confidence intervals were analyzed.

Results

Maximum dp/dt at 90 minutes of reperfusion and minimum dp/dt at 60 minutes of reperfusion showed a moderate positive correlation to that in working mode, respectively (Rs = 0.61, P = .04 and Rs = 0.60, P = .04). At 60 minutes of reperfusion, minimum dp/dt showed moderate positive correlation to tau (Rs = 0.52, P = .08). Myocardial oxygen consumption during reperfusion consistently decreased at least 30% compared to working mode (at 90 minutes as the highest during reperfusion, 3.3 ± 0.8; in working mode, 5.6 ± 1.4, mLO2/min/100 g, P < .001).

Conclusions

Functional parameters of contractility and relaxation measured during reperfusion by the modified balloon method showed significant correlations to respective parameters in working mode. This mitral valve sparing technique can be used to predict viability and ventricular function in the early phase of ex-vivo heart perfusion without loading the heart during working mode.

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.

Ex vivo lung perfusion in donation after circulatory death: A post hoc analysis of the Normothermic Ex Vivo Lung Perfusion as an Assessment of Extended/Marginal Donors Lungs trial

OBJECTIVE

Donation after circulatory death (DCD) donors offer the ability to expand the lung donor pool and ex vivo lung perfusion (EVLP) further contributes to this ability by allowing for additional evaluation and resuscitation of these extended criteria donors. We sought to determine the outcomes of recipients receiving organs from DCD EVLP donors in a multicenter setting.

METHODS

This was an unplanned post hoc analysis of a multicenter, prospective, nonrandomized trial that took place during 2011 to 2017 with 3 years of follow-up. Patients were placed into 3 groups based off procurement strategy: brain-dead donor (control), brain-dead donor evaluated by EVLP, and DCD donors evaluated by EVLP. The primary outcomes were severe primary graft dysfunction at 72 hours and survival. Secondary outcomes included select perioperative outcomes, and 1-year and 3-years allograft function and quality of life measures.

RESULTS

The DCD EVLP group had significantly higher incidence of severe primary graft dysfunction at 72 hours (P = .03), longer days on mechanical ventilation (P < .001) and in-hospital length of stay (P = .045). Survival at 3 years was 76.5% (95% CI, 69.2%-84.7%) for the control group, 68.3% (95% CI, 58.9%-79.1%) for the brain-dead donor group, and 60.7% (95% CI, 45.1%-81.8%) for the DCD group (P = .36). At 3-year follow-up, presence observed bronchiolitis obliterans syndrome or quality of life metrics did not differ among the groups.

CONCLUSIONS

Although DCD EVLP allografts might not be appropriate to transplant in every candidate recipient, the expansion of their use might afford recipients stagnant on the waitlist a viable therapy.

Liver machine perfusion technology: Expanding the donor pool to improve access to liver transplantation

The imbalance between organ supply and demand continues to limit the broader benefits of organ transplantation. Machine perfusion (MP) may increase the supply of donor livers by expanding the use of extended-criteria donors. Using the United Network for Organ Sharing/Organ Procurement and Transplantation Network and the Standard Transplant Analysis and Research dataset, we reviewed the effect of MP implementation on the behavior of transplant centers. We identified 15 high-utilizing MP centers that were matched to suitable controls based on volume and geographical proximity. We conducted a differences-in-differences analysis using linear regression to estimate the impact of MP adoption on the transplant centers' donor utilization. We found a significant increase in cold ischemia time and organs with donor warm ischemia time over 30 minutes (P < .05). After removing one outlier center, the analysis showed that these centers through MP accepted overall more donation after circulatory death donors, donation after circulatory death donors over 50 years old, donors with macrovesicular steatosis greater than 30% on liver biopsy, and donor warm ischemia time over 30 minutes (P < .05). MP has allowed centers to expand their use of extended-criteria donors beyond traditional cutoffs and to increase patient access to liver transplantation.

Current Techniques and Indications for Machine Perfusion and Regional Perfusion in Deceased Donor Liver Transplantation

Since the advent of University of Wisconsin preservation solution in the 1980s, clinicians have learned to work within its confines. While affording improved outcomes, considerable limitations still exist and contribute to the large number of livers that go unused each year, often for fear they may never work. The last 10 years have seen the widespread availability of new perfusion modalities which provide an opportunity for assessing organ viability and prolonged organ storage. This review will discuss the role of in situ normothermic regional perfusion for livers donated after circulatory death. It will also describe the different modalities of ex situ perfusion, both normothermic and hypothermic, and discuss how they are thought to work and the opportunities afforded by them.

HTK vs. HTK-N for Coronary Endothelial Protection during Hypothermic, Oxygenated Perfusion of Hearts Donated after Circulatory Death

Protection of the coronary arteries during donor heart maintenance is pivotal to improve results and prevent the development of coronary allograft vasculopathy. The effect of hypothermic, oxygenated perfusion (HOP) with the traditional HTK and the novel HTK-N solution on the coronary microvasculature of donation-after-circulatory-death (DCD) hearts is known. However, the effect on the coronary macrovasculature is unknown. Thus, we maintained porcine DCD hearts by HOP with HTK or HTK-N for 4 h, followed by transplantation-equivalent reperfusion with blood for 2 h. Then, we removed the left anterior descending coronary artery (LAD) and compared the endothelial-dependent and -independent vasomotor function of both groups using bradykinin and sodium-nitroprusside (SNP). We also determined the transcriptome of LAD samples using microarrays. The endothelial-dependent relaxation was significantly better after HOP with HTK-N. The endothelial-independent relaxation was comparable between both groups. In total, 257 genes were expressed higher, and 668 genes were expressed lower in the HTK-N group. Upregulated genes/pathways were involved in endothelial and vascular smooth muscle cell preservation and heart development. Downregulated genes were related to ischemia/reperfusion injury, oxidative stress, mitochondrion organization, and immune reaction. The novel HTK-N solution preserves the endothelial function of DCD heart coronary arteries more effectively than traditional HTK.

Transcriptomic Changes in the Myocardium and Coronary Artery of Donation after Circulatory Death Hearts following Ex Vivo Machine Perfusion

Donation after circulatory death (DCD) hearts are predominantly maintained by normothermic blood perfusion (NBP). Nevertheless, it was shown that hypothermic crystalloid perfusion (HCP) is superior to blood perfusion to recondition left ventricular (LV) contractility. However, transcriptomic changes in the myocardium and coronary artery in DCD hearts after HCP and NBP have not been investigated yet. In a pig model, DCD hearts were harvested and maintained for 4 h by NBP (DCD-BP group, N = 8) or HCP with oxygenated histidine-tryptophane-ketoglutarate (HTK) solution (DCD-HTK, N = 8) followed by reperfusion with fresh blood for 2 h. In the DCD group (N = 8), hearts underwent reperfusion immediately after procurement. In the control group (N = 7), no circulatory death was induced. We performed transcriptomics from LV myocardial and left anterior descending (LAD) samples using microarrays (25,470 genes). We applied the Boruta algorithm for variable selection to identify relevant genes. In the DCD-BP group, compared to DCD, six genes were regulated in the myocardium and 1915 genes were regulated in the LAD. In the DCD-HTK group, 259 genes were downregulated in the myocardium and 27 in the LAD; and 52 genes were upregulated in the myocardium and 765 in the LAD, compared to the DCD group. We identified seven genes of relevance for group identification: ITPRIP, G3BP1, ARRDC3, XPO6, NOP2, SPTSSA, and IL-6. NBP resulted in the upregulation of genes involved in mitochondrial calcium accumulation and ROS production, the reduction in microvascular endothelial sprouting, and inflammation. HCP resulted in the downregulation of genes involved in NF-κB-, STAT3-, and SASP-activation and inflammation.

Mitochondrial transplantation preserves myocardial function and viability in pediatric and neonatal pig hearts donated after circulatory death

OBJECTIVE

Mitochondrial transplantation has been shown to preserve myocardial function and viability in adult porcine hearts donated after circulatory death (DCD) . Herein, we investigate the efficacy of mitochondrial transplantation for the preservation of myocardial function and viability in neonatal and pediatric porcine DCD heart donation.

METHODS

Circulatory death was induced in neonatal and pediatric Yorkshire pigs by cessation of mechanical ventilation. Hearts underwent 20 or 36 minutes of warm ischemia time (WIT), 10 minutes of cold cardioplegic arrest, and then were harvested for ex situ heart perfusion (ESHP). Following 15 minutes of ESHP, hearts received either vehicle (VEH) or vehicle containing isolated autologous mitochondria (MITO). A sham nonischemic group (SHAM) did not undergo WIT, mimicking donation after brain death heart procurement. Hearts underwent 2 hours each of unloaded and loaded ESHP perfusion.

RESULTS

Following 4 hours of ESHP perfusion, left ventricle developed pressure, dP/dt max, and fractional shortening were significantly decreased (P < .001) in DCD hearts receiving VEH compared with SHAM hearts. In contrast, DCD hearts receiving MITO exhibited significantly preserved left ventricle developed pressure, dP/dt max, and fractional shortening (P < .001 each vs VEH, not significant vs SHAM). Infarct size was significantly decreased in DCD hearts receiving MITO as compared with VEH (P < .001). Pediatric DCD hearts subjected to extended WIT demonstrated significantly preserved fractional shortening and significantly decreased infarct size with MITO (P < .01 each vs VEH).

CONCLUSIONS

Mitochondrial transplantation in neonatal and pediatric pig DCD heart donation significantly enhances the preservation of myocardial function and viability and mitigates against damage secondary to extended WIT.

Donor utilization in heart transplant with donation after circulatory death in the United States

Heart transplantation using donation after circulatory death (DCD) was recently adopted in the United States. This study aimed to characterize organ yield from adult (≥18 years) DCD heart donors in the United States using the United Network for Organ Sharing registry. The registry does not identify potential donors who do not progress to circulatory death, and only those who progressed to death were included for analysis. Outcomes included organ recovery from the donor operating room and organ utilization for transplant. Multiple logistic regression was used to identify predictors of heart recovery and utilization. Among 558 DCD procurements, recovery occurred in 89.6%, and 92.5% of recovered hearts were utilized for transplant. Of 506 DCD procurements with available data, 65.0% were classified as direct procurement and perfusion and 35.0% were classified as normothermic regional perfusion (NRP). Logistic regression identified that NRP, shorter agonal time, younger donor age, and highest volume of organ procurement organizations were independently associated with increased odds for heart recovery. NRP independently predicted heart utilization after recovery. DCD heart utilization in the United States is satisfactory and consistent with international experience. NRP procurements have a higher yield for DCD heart transplantation compared with direct procurement and perfusion, which may reflect differences in donor assessment and acceptance criteria.

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.

Acute rejection in donation after circulatory death (DCD) heart transplants

BACKGROUND

Donation after circulatory death (DCD) heart transplantation has promising early survival, but the effects on rejection remain unclear.

METHODS

The United Network for Organ Sharing database was queried for adult heart transplants from December 1, 2019, to December 31, 2021. Multiorgan transplants and loss to follow-up were excluded. The primary outcome was acute rejection, comparing DCD and donation after brain death (DBD) transplants.

RESULTS

A total of 292 DCD and 5,582 DBD transplants met study criteria. Most DCD transplants were transplanted at status 3-4 (61.0%) compared to 58.6% of DBD recipients at status 1-2. DCD recipients were less likely to be hospitalized at transplant (26.7% vs 58.3%, p < 0.001) and to require intra-aortic balloon pumping (IABP; 9.6% vs 28.9%, p < 0.001), extracorporeal membrane oxygenation (ECMO; 0.3% vs 5.9%, p < 0.001) or temporary left ventricular assist device (LVAD; 1.0% vs 2.7%, p < 0.001). DCD recipients were more likely to have acute rejection prior to discharge (23.3% vs 18.4%, p = 0.044) and to be hospitalized for rejection (23.4% vs 11.4%, p = 0.003) at a median follow-up of 15 months; the latter remained significant after propensity matching. On multivariable logistic regression, DCD donation was an independent predictor of acute rejection (odds ratio [OR] 1.47, 95% confidence interval [CI] 1.00-2.15, p = 0.048) and hospitalization for rejection (OR 2.03, 95% CI 1.06-3.70, p = 0.026). On center-specific subgroup analysis, DCD recipients continued to have higher rates of hospitalization for rejection (23.4% vs 13.8%, p = 0.043).

CONCLUSIONS

DCD recipients are more likely to experience acute rejection. Early survival is similar between DCD and DBD recipients, but long-term implications of increased early rejection in DCD recipients require further investigation.

Post-transplant outcomes and financial burden of donation after circulatory death donor liver transplant after the implementation of acuity circle policy

BACKGROUND

After implementation of the Acuity Circles (AC) allocation policy, use of DCD liver grafts has increased in the United States.

METHODS

We evaluated the impact of AC on rates of DCD-liver transplants (LT), their outcomes, and medical costs in a single practice. Adult LT patients were classified into three eras: Era 1 (pre-AC, 1/01/2015-12/31/2017); Era 2 (late pre-AC era, 1/01/2018-02/03/2020); and Era 3 (AC era, 05/10/2020-09/30/2021).

RESULTS

A total of 520 eligible LTs were performed; 87 were DCD, and 433 were DBD. With each successive era, the proportion of DCD increased (Era 1: 11%; Era 2: 20%; Era 3: 24%; p < .001). DCD recipients had longer ICU stays, higher re-admission/re-operation rates, and higher incidence of ischemic cholangiopathy compared to those with DBD. Direct, surgical, and ICU costs during first admission were higher with DCD than DBD (+8.0%, p < .001; +4.2%, p < .001; and +33.3%, p = .001). DCD-related costs increased after Era 1 (Direct: +4.9% [Era 2 vs. 1] and +12.4% [Era 3 vs. 1], p = .04; Surgical: +17.7% and +21.7%, p < .001). In the AC era, there was a significantly higher proportion of donors ≥50 years, and more national organ sharing. Compared to DCD from donors <50 years, DCD from donors ≥50 years was associated with significantly higher total direct, surgical, and ICU costs (+12.6%, p = .01; +9.5%, p = .01; +84.6%, p = .03).

CONCLUSIONS

The proportion of DCD-LT, especially from older donors, has increased after the implementation of AC policies. These changes are likely to be associated with higher costs in the AC era.

EISOR Delivery: Regional experience with sharing equipe, equipment & expertise to increase cDCD donor pool in time of pandemic

Donation after circulatory death (DCD) programs are expanding in Europe, in the attempt to expand donors pool. Even in controlled DCD donors, however, a protracted warm ischemia time occurring in the perimortem period might damage organs, making these unsuitable for transplantation. Implementing a strategy of extracorporeal interval support for organ retrieval (EISOR), a regional reperfusion with normothermic, oxygenated blood provides a physiologic environment allowing extensive assessment of potential grafts, and potentially promotes recovery of native function. Here we report the results of a multi-center retrospective cohort study including 29 Maastricht Category III controlled DCD donors undergoing extracorporeal support in a regional DCD/EISOR Training Center, and in the network of referring In-Training Centers, under the liaison of the regional Transplant Coordination Center during COVID-19 pandemic, between March 2020 and November 2021. The study aims to understand whether a mobile, experienced EISOR team implementing a consistent technique and sharing its equipe, expertise and equipment in a regional network of hospitals, might be effective and efficient in implementing the regional DCD program activity even in a highly stressed healthcare system.

Early national trends of lung allograft use during donation after circulatory death heart procurement in the United States

Objective

Innovative technology such as normothermic regional perfusion and the Organ Care System has expanded donation after circulatory death heart transplantation. We wanted to investigate the impact of donation after circulatory death heart procurement in concurrent lung donation and implantation at a national level.

Methods

We reviewed the United Network for Organ Sharing database for heart donation between December 2019 and March 2022. Donation after circulatory death donors were separated from donation after brain death donors and further categorized based on concomitant organ procurement of lung and heart, or heart only.

Results

A total of 8802 heart procurements consisted of 332 donation after circulatory death donors and 8470 donation after brain death donors. Concomitant lung procurement was lower among donation after circulatory death donors (19.3%) than in donation after brain death donors (38.0%, P < .001). The transplant rate of lungs in the setting of concomitant procurement is 13.6% in donation after circulatory death, whereas it is 38% in donation after brain death (P < .001). Of the 121 lungs from 64 donation after circulatory death donors, 22 lungs were retrieved but discarded (32.2%). Normothermic regional perfusion was performed in 37.3% of donation after circulatory death donors, and there was no difference in lung use between normothermic regional perfusion versus direct procurement and perfusion (20.2% and 18.8%). There was also no difference in 1-year survival between normothermic regional perfusion and direct procurement and perfusion.

Conclusions

Although national use of donation after circulatory death hearts has increased, donation after circulatory death lungs has remained at a steady state. The implantation of lungs after concurrent procurement with the heart remains low, whereas transplantation of donation after circulatory death hearts is greater than 90%. The use of normothermic regional perfusion lungs has been controversial, and we report comparable 1-year outcomes to standard donation after circulatory death lungs. Further studies are warranted to investigate the underlying mechanisms of normothermic regional perfusion on lung function.

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.

The effect of warm ischemia and donor ejection fraction on 30-day mortality after donation after circulatory death heart transplantation: A national database analysis

Donation after circulatory death (DCD) donor hearts recovered using the direct procurement and perfusion method experience variable durations of warm ischemia at the time of procurement (WIP). We used the Organ Procurement and Transplantation Network database to assess the effect of WIP on 30-day mortality after DCD heart transplantation. The analysis evaluated outcomes in 237 recipients of DCD heart transplantation, demonstrating an optimal WIP cut point of <36 minutes. Multivariable logistic regression modeling identified donor left ventricular ejection fraction (LVEF) <60% as an independent predictor of 30-day mortality. The area under the receiver operating characteristic curve for predicting 30-day mortality based on WIP ≥36 minutes and donor LVEF <60% was 0.90. Based on these findings, we do not recommend proceeding with DCD heart transplantation for patients with WIP ≥36 minutes, particularly in donors with LVEF <60%.

Outcomes of Heart Transplant Donation After Circulatory Death

BACKGROUND

Heart transplantation using donation after circulatory death (DCD) allografts is increasingly common, expanding the donor pool and reducing transplant wait times. However, data remain limited on clinical outcomes.

OBJECTIVES

We sought to compare 6-month and 1-year clinical outcomes between recipients of DCD hearts, most of them recovered with the use of normothermic regional perfusion (NRP), and recipients of donation after brain death (DBD) hearts.

METHODS

We conducted a single-center retrospective observational study of all adult heart-only transplants from January 2020 to January 2023. Recipient and donor data were abstracted from medical records and the United Network for Organ Sharing registry, respectively. Survival analysis and Cox regression were used to compare the groups.

RESULTS

During the study period, 385 adults (median age 57.4 years [IQR: 48.0-63.7 years]) underwent heart-only transplantation, including 122 (32%) from DCD donors, 83% of which were recovered with the use of NRP. DCD donors were younger and had fewer comorbidities than DBD donors. DCD recipients were less often hospitalized before transplantation and less likely to require pretransplantation temporary mechanical circulatory support compared with DBD recipients. There were no significant differences between groups in 1-year survival, incidence of severe primary graft dysfunction, treated rejection during the first year, or likelihood of cardiac allograft vasculopathy at 1 year after transplantation.

CONCLUSIONS

In the largest single-center comparison of DCD and DBD heart transplantations to date, outcomes among DCD recipients are noninferior to those of DBD recipients. This study adds to the published data supporting DCD donors as a safe means to expand the heart donor pool.

Single center experience and literature review of kidney transplantation from non-ideal donors with acute kidney injury: Risk and reward

INTRODUCTION

There is limited experience transplanting kidneys from either expanded criteria donors (ECD) or donation after circulatory death (DCD) deceased donors with terminal acute kidney injury (AKI).

METHODS

AKI kidneys were defined by a donor terminal serum creatinine level >2.0 mg/dL whereas non-ideal deceased donor (NIDD) kidneys were defined as AKI/DCD or AKI/ECDs.

RESULTS

From February 2007 to March 2023, we transplanted 266 single AKI donor kidneys including 29 from ECDs, 29 from DCDs (n = 58 NIDDs), and 208 from brain-dead standard criteria donors (SCDs). Mean donor age (43.7 NIDD vs. 33.5 years SCD), KDPI (66% NIDD vs. 45% SCD), and recipient age (57 NIDD vs. 51 years SCD) were higher in the NIDD group (all p < .01). Mean waiting times (17.8 NIDD vs. 24.2 months SCD) and dialysis duration (34 NIDD vs. 47 months SCD) were shorter in the NIDD group (p < .05). Delayed graft function (DGF, 48%) and 1-year graft survival (92.7% NIDD vs. 95.9% SCD) was similar in both groups. Five-year patient and kidney graft survival rates were 82.1% versus 89.9% and 82.1% versus 75.2% (both p = NS) in the NIDD versus SCD groups, respectively.

CONCLUSIONS

The use of kidneys from AKI donors can be safely liberalized to include selected ECD and DCD donors.

Donation after circulatory death: A transplant cardiologist's take on neuroprognostication

Donation after circulatory death (DCD) is becoming increasingly utilized in heart transplantation and has the potential to further expand the donor pool. As transplant cardiologists gain more familiarity with DCD donor selection, there are many issues that lack consensus including how we incorporate the neurologic examination, how we measure functional warm ischemic time (fWIT), and what fWIT thresholds are acceptable. DCD donor selection calls for prognostication tools to help determine how quickly a donor may expire, and in current practice there is no standardization in how we make these predictions. Current scoring systems help to determine which donor may expire within a specified time window either require the temporary disconnection of ventilatory support or do not incorporate any neurologic examination or imaging. Moreover, the specified time windows differ from other DCD solid organ transplantation without standardization or strong scientific justification for these thresholds. In this perspective, we highlight the challenges faced by transplant cardiologists as they navigate the muddy waters of neuroprognostication in DCD cardiac donation. Given these difficulties, this is also a call to action for the creation of a more standardized approach to improve the DCD donor selection process for appropriate resource allocation and organ utilization.

Viability assessment of livers donated after circulatory determination of death during normothermic regional perfusion

BACKGROUND

Abdominal normothermic regional perfusion (A-NRP) allows in-situ reperfusion and recovery of abdominal organs metabolism in donors after circulatory death (DCD). Besides improving liver transplantation outcomes, liver injury and function can be assessed during A-NRP.

METHODS

To refine liver viability assessment during A-NRP, prospectively collected data of controlled DCD donors managed at our Institution between October 2019 and May 2022 were retrospectively analyzed. Baseline characteristics, procedural variables and A-NRP parameters of donors whose liver was successfully transplanted were compared to those of donors whose liver was discarded.

RESULTS

Twenty-seven donors were included and in 20 (74%) the liver was accepted (positive outcome). No differences between study groups were observed concerning baseline characteristics and warm ischemia times (WIT). Initial lactate levels were positively correlated with functional WIT (r2  = 0.4, p = 0.04), whereas transaminase levels were not. Blood flow during A-NRP was comparable, whereas oxygen consumption (VO2 ) was significantly higher in the positive outcome group after 1 h. Time courses of lactate, AST and ALT were significantly different between study groups (p < 0.001). Donors whose liver was accepted showed faster lactate clearance, a difference which was amplified by normalizing lactate clearance to oxygen delivery (DO2 ) and VO2 . Lactate clearance was correlated to transaminase levels and DO2 -normalized lactate clearance was the parameter best discriminating between study groups.

CONCLUSIONS

DO2 -normalized lactate clearance may represent an element of liver viability assessment during A-NRP.

Preclinical Study of DCD and Normothermic Perfusion for Visceral Transplantation

Considering recent clinical and experimental evidence, expectations for using DCD-derived intestines have increased considerably. However, more knowledge about DCD procedure and long-term results after intestinal transplantation (ITx) is needed. We aimed to describe in detail a DCD procedure for ITx using normothermic regional perfusion (NRP) in a preclinical model. Small bowel was obtained from pigs donors after 1 h of NRP and transplanted to the recipients. Graft Intestinal samples were obtained during the procedure and after transplantation. Ischemia-reperfusion injury (Park-Chiu score), graft rejection and transplanted intestines absorptive function were evaluated. Seven of 8 DCD procedures with NRP and ITx were successful (87.5%), with a good graft reperfusion and an excellent recovery of the recipient. The architecture of grafts was well conserved during NRP. After an initial damage of Park-chiu score of 4, all grafts recovered from ischemia-reperfusion, with no or very subtle alterations 2 days after ITx. Most recipients (71.5%) did not show signs of rejection. Only two cases demonstrated histologic signs of mild rejection 7 days after ITx. Interestingly intestinal grafts showed good absorptive capacity. The study's results support the viability of intestinal grafts from DCD using NRP, contributing more evidence for the use of DCD for ITx.

Successful aortic arch cannulation and perfusion of a heart donated after circulatory death: A case report

INTRODUCTION

We describe successful aortic arch cannulation and perfusion of a heart donated after circulatory death using the Transmedics Organ Care System™.

CASE REPORT

A 47-year old man developed advanced heart failure symptoms after prior mustard operation for transposition of the great arteries. He matched a DCD-donor and required an elongated aorta for implantation due to his altered anatomy. The donor heart was retrieved and successfully perfused via aortic arch cannulation for 4.5 h with satisfactory perfusion parameters.

DISUSSION

Although Transmedics advises against aortic arch cannulation due to concerns regarding malperfusion, satisfactory and safe perfusion can be achieved by careful positioning of the heart. Awareness and attention to the occurrence of malperfusion is mandatory, especially during transport, to achieve satisfactory outcome.

CONCLUSION

Aortic arch cannulation is feasible without compromising quality of perfusion. This is relevant for patient that require an elongated aorta after surgically corrected congenital heart disease.

DCD liver transplant in patients with a MELD over 35

Introduction

Donation after circulatory death (DCD) liver transplantation (LT) makes up well less than 1% of all LTs with a Model for End-Stage Liver Disease (MELD)≥35 in the United States. We hypothesized DCD-LT yields acceptable ischemia-reperfusion and reasonable outcomes for recipients with MELD≥35.

Methods

We analyzed recipients with lab-MELD≥35 at transplant within the UCSF (n=41) and the UNOS (n=375) cohorts using multivariate Cox regression and propensity score matching.

Results

In the UCSF cohort, five-year patient survival was 85% for DCD-LTs and 86% for matched-Donation after Brain Death donors-(DBD) LTs (p=0.843). Multivariate analyses showed that younger donor/recipient age and more recent transplants (2011-2021 versus 1999-2010) were associated with better survival. DCD vs. DBD graft use did not significantly impact survival (HR: 1.2, 95%CI 0.6-2.7). The transaminase peak was approximately doubled, indicating suggesting an increased ischemia-reperfusion hit. DCD-LTs had a median post-LT length of stay of 11 days, and 34% (14/41) were on dialysis at discharge versus 12 days and 22% (9/41) for DBD-LTs. 27% (11/41) DCD-LTs versus 12% (5/41) DBD-LTs developed a biliary complication (p=0.095). UNOS cohort analysis confirmed patient survival predictors, but DCD graft emerged as a risk factor (HR: 1.5, 95%CI 1.3-1.9) with five-year patient survival of 65% versus 75% for DBD-LTs (p=0.016). This difference became non-significant in a sub-analysis focusing on MELD 35-36 recipients. Analysis of MELD≥35 DCD recipients showed that donor age of <30yo independently reduced the risk of graft loss by 30% (HR, 95%CI: 0.7 (0.9-0.5), p=0.019). Retransplant status was associated with a doubled risk of adverse event (HR, 95%CI: 2.1 (1.4-3.3), p=0.001). The rejection rates at 1y were similar between DCD- and DBD-LTs, (9.3% (35/375) versus 1,541 (8.7% (1,541/17,677), respectively).

Discussion

In highly selected recipient/donor pair, DCD transplantation is feasible and can achieve comparable survival to DBD transplantation. Biliary complications occurred at the expected rates. In the absence of selection, DCD-LTs outcomes remain worse than those of DBD-LTs.

Thoracoabdominal normothermic regional perfusion in donation after circulatory death does not restore brain blood flow

Use of thoracoabdominal normothermic regional perfusion (TA-NRP) during donation after circulatory death (DCD) is an important advance in organ donation. Prior to establishing TA-NRP, the brachiocephalic, left carotid, and left subclavian arteries are ligated, thereby eliminating anterograde brain blood flow via the carotid and vertebral arteries. While theoretical concerns have been voiced that TA-NRP after DCD may restore brain blood flow via collaterals, there have been no studies to confirm or refute this possibility. We evaluated brain blood flow using intraoperative transcranial Doppler (TCD) in two DCD TA-NRP cases. Pre-extubation, anterior and posterior circulation brain blood flow waveforms were present in both cases, similar to the waveforms detected in a control patient on mechanical circulatory support undergoing cardiothoracic surgery. Following declaration of death and initiation of TA-NRP, no brain blood flow was detected in either case. Additionally, there was absence of brainstem reflexes, no response to noxious stimuli and no respiratory effort. These TCD results demonstrate that DCD with TA-NRP did not restore brain blood flow.

Heart transplantation from donation after circulatory death: Impact on waitlist time and transplant rate

The effect of using donation after circulatory death (DCD) hearts on waitlist outcomes has not been substantiated. We retrospectively analyzed 184 heart transplant (HT) candidates at our institution from 2019 to 2021. Patients were stratified into 2 observation periods centered on September 12, 2020, when the adult DCD HT program officially began. The primary outcome was a comparison of transplant rate between period 1 (pre-DCD) and period 2 (post-DCD). Secondary outcomes included waitlist time-to-transplant, waitlist mortality rate, independent predictors of incidence of HT, and posttransplant outcomes. A total of 165 HTs (n = 92 in period 1 and n = 73 in period 2) were performed. The median waitlist time-to-transplant decreased from 47.5 to 19 days in periods 1 and 2, respectively (P = .004). The transplant rate increased from 181 per 100 patient-years in period 1 to 579 per 100 patient-years in period 2 (incidence rate ratio, 1.87; 95% CI, 1.04-3.38; P = .038). There were no statistical differences in waitlist mortality rate (P = .566) and 1-year survival (P = .699) between the 2 periods. DCD HTs (n = 36) contributed to 49.3% of overall HT activity in period 2. We concluded that utilization of DCD hearts significantly reduced waitlist time and increased transplant rate. Short-term posttransplant outcomes were comparable between the pre-DCD and post-DCD periods.

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.

Improving Diastolic and Microvascular Function in Heart Transplantation with Donation after Circulatory Death

The impact of the machine perfusion of donation after circulatory death (DCD) hearts with the novel Custodiol-N solution on diastolic and coronary microvascular dysfunction is unknown. Porcine DCD-hearts were maintained four hours by perfusion with normothermic blood (DCD-B), hypothermic Custodiol (DCD-C), or Custodiol-N (DCD-CN), followed by one hour of reperfusion with fresh blood, including microvascular and contractile evaluation. In another group (DCD group), one hour of reperfusion, including microvascular and contractile evaluation, was performed without a previous maintenance period (all groups N = 5). We measured diastolic function with a balloon catheter and microvascular perfusion by Laser-Doppler-Technology, resulting in Laser-Doppler-Perfusion (LDP). We performed immunohistochemical staining and gene expression analysis. The developed pressure was improved in DCD-C and DCD-CN. The diastolic pressure decrement (DCD-C: -1093 ± 97 mmHg/s; DCD-CN: -1703 ± 329 mmHg/s; DCD-B: -690 ± 97 mmHg/s; p < 0.05) and relative LDP (DCD-CN: 1.42 ± 0.12; DCD-C: 1.11 ± 0.13; DCD-B: 1.22 ± 0.27) were improved only in DCD-CN. In DCD-CN, the expression of eNOS increased, and ICAM and VCAM decreased. Only in DCD-B compared to DCD, the pathways involved in complement and coagulation cascades, focal adhesion, fluid shear stress, and the IL-6 and IL-17 pathways were upregulated. In conclusion, machine perfusion with Custodiol-N improves diastolic and microvascular function and preserves the microvascular endothelium of porcine DCD-hearts.

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

Standard US practice for donation after circulatory death (DCD) abdominal organ procurement is superrapid recovery (SRR). A newer approach using thoracoabdominal normothermic regional perfusion (TA-NRP) shows promise for better recipient outcomes for all organs, but there are few reports of abdominal recipient outcomes from TA-NRP donors. We used the United Network for Organ Sharing data to identify all cardiac DCD donors from October 1, 2020, to May 20, 2022, and categorized them by recovery procedure (SRR vs TA-NRP). We then identified all liver, kidney, and pancreas recipients of these donors for whom 6-month outcome data were available and compared patient and graft survival, kidney delayed graft function (DGF), and biliary complications between TA-NRP DCD and SRR DCD organ recipients. Patient and graft survival did not differ significantly between groups for either kidney or liver recipients. Significantly fewer TA-NRP kidney recipients developed DGF (12.7% [15/118] vs 42.0% [84/200], P <.001), and TA-NRP and pumped kidneys had lower odds for DGF on multivariate analysis. No liver recipients in either group had biliary complications or were relisted for transplantation for ischemic cholangiopathy. Although long-term outcomes need to be investigated, our early results show similar outcomes for recipients of TA-NRP DCD abdominal organs versus recipients of SRR DCD abdominal organs. We believe that TA-NRP is an effective approach to expand the use of DCD organs.

Donation after circulatory death heart procurement strategy impacts utilization and outcomes of concurrently procured abdominal organs

INTRODUCTION

The impact of donation after circulatory death (DCD) heart procurement techniques on the utilization and outcomes of concurrently procured DCD livers and kidneys remains unclear.

METHODS

Using the United Network for Organ Sharing database, we identified 246 DCD donors whose heart was procured using direct procurement and ex-situ machine perfusion and 128 DCD donors whose heart was procured using in-situ thoracoabdominal normothermic regional perfusion (12/2019-03/2022). We evaluated the transplantation rate of concurrently procured DCD livers and kidneys (defined as the number of organs transplanted/total number of organs available for procurement) and their post-transplant outcomes.

RESULTS

The transplantation rate of concurrently procured DCD livers was higher with in-situ perfusion compared to direct procurement (67.1% vs 56.5%, p = 0.045). After excluding pediatric, multiorgan, and repeat transplant recipients, there was no difference in 6-month liver graft failure rate (direct procurement 0.9% vs in-situ perfusion 0%, p > 0.99). Recipients of kidneys procured with in-situ perfusion had less delayed graft function (11.3% vs 41.5%, p < 0.0001) shorter length of stay, and lower serum creatinine at discharge (both p < 0.05). Six-month recipient survival in the direct procurement and in-situ perfusion group were similar after DCD liver and kidney transplantation (p = 0.24 and 0.79 respectively).

CONCLUSIONS

Compared to direct procurement, DCD heart procurement with in-situ thoracoabdominal normothermic regional perfusion was associated with increased utilization of DCD livers and a lower incidence of delayed graft function in concurrently procured DCD kidneys. Broader implementation of DCD heart transplantation must maximize the transplant potential of concurrently procured abdominal organs and ensure their successful outcomes.

Ethical Issues in Donation following Circulatory Death: A Scoping Review Examining Changes over Time from 1993 to 2022

Background: Ethical frameworks for organ donation following circulatory death (DCD) were established >20 years ago. However, considerable variation exists among these, indicating consensus has not been reached on all issues. Additionally, advances such as cardiac DCD transplants and normothermic regional perfusion (NRP) may have reignited old debates.Methods: We reviewed the English-language literature addressing ethical issues in DCD from 1993 to 2022, examining changes in frequency with which ethical principles and their sub-themes identified within each, were addressed.Results: Non-maleficence was the most frequently addressed principle (192 of 199 articles), as well as the most varied, with 9 subthemes (versus 2-4 within each of the other bioethical principles).Conclusions: There were several changes in the terminology used to refer to DCD over time, and substantial interest in cardiac DCD and NRP in recent publications, arising in 11 and 19 of the 30 publications from 2018 to 2022.

Exploration of Optimal pH in Hypothermic Machine Perfusion for Rat Liver Grafts Retrieved after Circulatory Death

Ex vivo hypothermic machine perfusion (HMP) is a strategy for controlling ischemia-reperfusion injury in donation after circulatory death (DCD) liver transplantation. The pH of blood increases with a decrease in temperature and water dissociation, leading to a decrease in [H⁺]. This study aimed to verify the optimal pH of HMP for DCD livers. Rat livers were retrieved 30 min post-cardiac arrest and subjected to 3-h cold storage (CS) in UW solution (CS group) or HMP with UW-gluconate solution (machine perfusion [MP] group) of pH 7.4 (original), 7.6, 7.8, and 8.0 (MP-pH 7.6, 7.8, 8.0 groups, respectively) at 7-10 °C. The livers were subjected to normothermic perfusion to simulate reperfusion after HMP. All HMP groups showed greater graft protection compared to the CS group due to the lower levels of liver enzymes in the former. The MP-pH 7.8 group showed significant protection, evidenced by bile production, diminished tissue injury, and reduced flavin mononucleotide leakage, and further analysis by scanning electron microscopy revealed a well-preserved structure of the mitochondrial cristae. Therefore, the optimum pH of 7.8 enhanced the protective effect of HMP by preserving the structure and function of the mitochondria, leading to reduced reperfusion injury in the DCD liver.

Comparison of Different Ex-Vivo Preservation Strategies on Cardiac Metabolism in an Animal Model of Donation after Circulatory Death

Transplantation of heart following donation after circulatory death (DCD) was recently introduced into clinical practice. Ex vivo reperfusion following DCD and retrieval is deemed necessary in order to evaluate the recovery of cardiac viability after the period of warm ischemia. We tested the effect of four different temperatures (4 °C-18 °C-25 °C-35 °C) on cardiac metabolism during 3-h ex vivo reperfusion in a porcine model of DCD heart. We observed a steep fall in high-energy phosphate (ATP) concentrations in the myocardial tissue at the end of the warm ischemic time and only limited regeneration during reperfusion. Lactate concentration in the perfusate increased rapidly during the first hour of reperfusion and slowly decreased afterward. However, the temperature of the solution does not seem to have an effect on either ATP or lactate concentration. Furthermore, all cardiac allografts showed a significant weight increase due to cardiac edema, regardless of the temperature.

Metabolic Outcomes After Pancreas Transplant Alone From Donation After Circulatory Death Donors-The UK Transplant Registry Analysis

Extrapolating data from early DCD (donation after circulatory death) kidney transplantation, pancreas transplants from DCD grafts were feared to have worse metabolic outcomes. Hence, we aimed to address the question of pancreas transplant alone (PTA) from DCD donors-are our concerns justified? A UK transplant registry analysis of 185 PTA performed between 2005 and 2018 was done. All early graft losses (<3 months) were excluded to allow focus on the metabolic outcomes (HbA₁c, weight gain and incidence of secondary diabetic macrovascular complications). The aim was to compare the metabolic outcomes, rejection rates (including the need for steroids), patient and graft survival between DBD (Donation after brainstem death) and DCD groups. After excluding early graft losses, data from 162 PTA (DBD = 114 and DCD = 48) were analyzed. Body mass index of the donor was less in DCD group (DBD = 23.40 vs. DCD = 22.25, p = 0.006) and the rest of the baseline transplant characteristics were comparable. There were no significant differences in the HbA₁c, weight gain, rejection rate, and incidence of secondary diabetic macrovascular complications post-transplant between DBD and DCD recipients. The 1-, 5-, and 10-year patient and graft survival were similar in both the groups. PTA from DCD donors have equivalent metabolic outcomes and survival (patient/graft) as that of DBD donors.