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.

Simultaneous thoracic and abdominal donation after circulatory death organ recovery: the abdominal surgeon's perspective

PURPOSE OF THE REVIEW

To summarize the international experience with heart-liver (joint) donation after circulatory death (DCD) procurements and to explore the technical challenges in joint abdominal and thoracic DCD procurement.

RECENT FINDINGS

Following completion of the Donors After Circulatory Death Heart Trial in the US, combined thoracic and abdominal DCD is poised to become the standard of care, expanding access to life-saving heart and lung allografts. DCD heart procurement relies on collection of donor blood for priming of the normothermic perfusion pump, which delays cooling of abdominal organs and increases risk of ischemic injury. We review the effect of donor ischemia time on abdominal organs, with several proposed technical solutions to optimize transplant outcomes for all organs.

SUMMARY

The strategies reviewed in this manuscript may inform clinical decision-making, preoperative coordination between thoracic and abdominal procurement teams, and surgical technique for joint DCD procurements. Several approaches to organ procurement organization (OPO) and national policy, as well as future areas of focus for research are proposed.

The ethics of donation after circulatory death organ recovery: an overview of new considerations arising from procurement practice and policy changes

PURPOSE OF REVIEW

The aim of this study is to examine ethical issues raised by organ recovery from donors after circulatory death (DCD).

RECENT FINDINGS

Recent technological developments and policy modifications have implications for evolving ethical issues related to DCD organ procurement and donation. We identify four such changes and discuss the most significant ethical issues raised by each: the use of cardiac perfusion machines and the need to develop criteria to allow prioritization for organ preservation in joint thoracic-abdominal procurements, normothermic regional perfusion and the irreversibility criterion in the definition of death, practice variability in DCD withdrawal of care and death declarations, and equitable access to donation, and changes in organ procurement organization evaluation metrics and transplant system resource utilization.

SUMMARY

The evolution of DCD donation raises new ethical concerns that require further analysis to ensure that deceased donors, donor families and transplant recipients are treated respectfully and equitably.

End-Of-Life Care in the Potential Donor after Circulatory Death: A Systematic Review

Background

Donation after circulatory death (DCD) is becoming increasingly common, yet little is known about the way potential donors receive end-of-life care.

Purpose

The aims of this systematic review are to describe the current practice in end-of-life care for potential donors and identify metrics that are being used to assess discomfort among these patients.

Research design and Study Sample

This review encompasses published literature between June 1, 2000 and June 31, 2020 of end-of-life care received by potential DCD patients. The population of interest was defined as patients eligible for Maastracht classification III donation after circulatory death for a solid organ transplantation. Outcomes examined included: analgesic or palliative protocols, and surrogates of discomfort (eg dyspnea, agitation).

Results

Among 141 unique articles, 27 studies were included for full review. The primary reason for exclusion was lack of protocol description, or lack of reporting on analgesic medications. No primary research studies specifically examined distress in the DCD eligible population. Numerous professional guidelines were identified. Surveys of critical care practitioners identified concerns regarding the impact of symptom management on hastening the dying process in the DCD population as a potential barrier to end-of-life palliative treatment.

Conclusions

There is a paucity of empirical evidence for end-of-life symptom assessment and management for DCD patients. Key evidence gaps identified for DCD include the need for: i) a multidisciplinary structure of treatment teams and preferred environment for DCD, ii) objective tools for monitoring of distress in this patient population, and iii) evidence guiding the administration of analgesic medications following withdrawal of life sustaining therapy.

In vitro and In vivo assessment of a novel organ perfusion stent for successful flow separation in donation after cardiac death

Shortage of healthy donors' organs has appeared as one of the main challenges for organ transplantation. This study focuses on the novel endovascular device development to increase the number of available organs from cardiac death donors. The primary objective of this study is the design validation of a newly developed stent graft for the abdominal organ perfusion with cardiac blood flow isolation. In this paper, the effectiveness of the device design has been validated via the assessment of the device performance both in vitro and in vivo. The radial force of stent structure was first numerically analyzed using finite element method, then was quantified experimentally. The blood perfusion parameters were investigated to demonstrate their effect on the blood delivered to the abdominal organs, maintaining the organs healthy for donation. In vitro flow leakage was measured using a 3-D printing-based silicone aortic model to evaluate the isolation between cardiac flow and perfusion flow with minimum values. Following the design validation process, a functional prototype stent graft has been successfully fabricated using optimized laser welding conditions and subsequent joining processes. In vivo porcine study results have demonstrated smooth delivery and successful placement of the device showing complete cardiac flow separation isolating abdominal regions only with the oxygenated blood flow.

The impact of machine perfusion of the heart on warm ischemia time and organ yield in donation after circulatory death

Successful normothermic machine perfusion of heart allografts (MPH) has led to rapid growth in transplantation of donation after circulatory death (DCD) heart allografts but has introduced complexity in the procurement process. This study examines the impact of MPH use in DCD procurements on warm ischemia time (WIT) and organ yield. DCD procurements from 2019 to 2020 were identified using the OPTN database. Procurements with and without the use of MPH were compared using propensity score matching. Observed to expected (O:E) yield ratios were calculated, where the expected values were obtained using the models developed by the Scientific Registry of Transplant Recipients. In total, 1237 DCD procurements met inclusion criteria (MPH: 109 and control: 1128). After PSM, no difference was found between groups in median total WIT (24.0 min vs. 24.0 min, p = .89), but the MPH group demonstrated shorter median operative WIT (circulatory arrest to cross-clamp; 8.7 min vs. 10.9 min, p = .003). The overall organ yield of DCD heart donors was observed to be 33% higher than expected (O:E 1.33; 95% CI: 1.22-1.45). Observed yield of non-heart organs was not significantly different from expected for liver, kidney, lung, and pancreas grafts. MPH use in DCD procurements does not lead to delays in WIT and does not negatively affect organ yield of other concurrently procured organs.

Potential donor characteristics and decisions made by organ procurement organization staff: Results of a discrete choice experiment

Organ procurement organizations (OPOs) evaluate referrals for deceased organ donation in the United States. Efforts to expand the donor pool, such as the HIV organ policy equity (HOPE) Act that permits transplants from HIV-positive donors to HIV-positive recipients, can only succeed if OPOs pursue referrals. However, relatively little is known about how OPO staff evaluate referrals. To better understand this process, OPO staff completed a discrete choice experiment to quantify the relative importance of seven donor characteristics on the decision to pursue a theoretical donor. Relative importance was defined by Partworth utility using a hierarchical Bayesian conditional logit model. There were 51 respondents from 36 of 58 OPOs in the United States. Of the seven attributes, organ and tissue potential were the most influential, followed by age, type of death, HIV status, donor registration, and Hepatitis C status. To be preferred to an HIV-negative donor, an HIV-positive donor needed to have the potential to donate two additional organs. These data provide insight into the preferences of OPO referral staff and may help explain the lower than expected number of HIV-positive transplants performed since the passage of the HOPE Act.

Donation after circulatory death: opportunities on the horizon

PURPOSE OF REVIEW

Organ transplantation remains the gold standard therapy for many end-organ diseases. The demand for donor organs continues to grow to far exceed supply. This review summarizes recent protocols, procedures, and ethics surrounding the increased utilization of donors after circulatory death for transplantation.

RECENT FINDINGS

An increasing number of centers are utilizing donation after circulatory death, and outcomes are improving. Although outcomes from donors after brain death continue to be the primary source of donation, circulatory death outcomes continue to improve approaching the level of brain death donors.

SUMMARY

Donation after circulatory death offers a real opportunity to narrow the supply and demand issue with organ donation. Outcomes are improving, and protocols continue to evolve.