Transplantation of hearts donated after circulatory death (DCD) is associated with similar short-term clinical outcomes as hearts donated after brain death (DBD), except for transient posttransplant right heart dysfunction, a single-center analysis suggests.
The right-heart dysfunction resolved by 3 weeks post transplant, and recipient mortality was similar for those receiving DCD and DBD, which is considered standard of care (SOC).
Furthermore, the median waiting list time was significantly shorter for DCD recipients than for SOC recipients (17 vs 70 days).
The authors suggest that use of DCD hearts could expand the donor pool by as much as 30%.
"Now that we and others have demonstrated the safety of this technique, I believe it is our obligation as a transplant community to use these organs and not allow them to be wasted," David A. D'Alessandro, MD, of Massachusetts General Hospital (MGH), in Boston, told theheart.org | Medscape Cardiology.
"I will caution that DCD heart transplantation is labor-intensive, and there is a learning curve which can potentially put patients at risk," he added. "It is vitally important, therefore, that we learn from each other's experiences to flatten this curve."
The study was published online September 26 in the Journal of the American College of Cardiology.
D'Alessandro and colleagues compared the hemodynamic and clinical profiles of 47 DCD hearts with 166 SOC hearts implanted at MGH between 2016 and 2022. DCD hearts were maintained using a proprietary warm perfusion circuit organ care system (OCS, TransMedics).
Baseline characteristics were similar between the groups, except the DCD heart recipients were younger (mean age, 55 vs 59); they were less likely to be an inpatient at the time of transplant (26% vs 49%); and they had lower pulmonary vascular resistance (1.73 WU vs 2.26 WU).
The median time from DCD consent to transplant was significantly shorter than for SOC hearts (17 vs 70 days). However, there was a higher, though not statistically significant, incidence of severe primary graft dysfunction at 24 hours post transplant with DCD (10.6% vs SOC 3.6%), leading five DCD recipients (10.6%) and nine SOC recipients (5.4%) to receive venoarterial extracorporeal membrane oxygenation.
Right heart function was significantly impaired in DCD vs SOC recipients 1 week post transplant, with higher median right atrial pressure (10 mm Hg vs 7 mm Hg); higher right atrial pressure to pulmonary capillary wedge pressure ratio (0.64 vs 0.57); and lower pulmonary arterial pulsatility index (1.66 vs 2.52).
However, by 3 weeks post transplant, right heart function was similar between the groups, as was mortality at 30 days (0 vs 2%) and 1 year (3% vs 8%).
Furthermore, hospital length of stay (LOS) following transplant, intensive care unit (ICU) LOS, ICU readmissions, and 30-day readmissions were similar between the groups.
"We and others will continue to push the boundaries of this technique to understand if we can safely extend the warm ischemic time, which could make additional organs available," D'Alessandro said. "We will also be exploring additional ways to monitor and assess organ health and viability ex situ and potential avenues of treatment which could repair and optimize organ function.
"A successful DCD heart transplant program requires institutional and team commitment," he added, "and there are clinical nuances which should be appreciated to minimize patient risks associated with the obligate learning curve."
Ulrich P. Jorde, MD, of Montefiore Medical Center in New York City, author of a related editorial, concludes that heart donation after circulatory death "promises significant expansion of the donor pool and will lead to many lives saved" and that "the current investigation is a timely and important contribution to this effort."
However, he notes, "it must be acknowledged that donation after cardiac death has evoked significant controversy regarding the ethics of this approach," particularly when using a technique called normothermic regional perfusion (NRP), in which, after declaration of death and ligation of cerebral vessels, the heart is resuscitated in situ using extracorporeal membrane oxygenation, as opposed to the proprietary warm perfusion OCS used in this study.
"Central to this discussion is the definition of death and its irreversibility," Jorde notes. "In contrast to DBD, where brain death protocols are well established and accepted by societies across the globe, DCD protocol rules, eg, standoff times after complete cessation of circulation, continue to vary even within national jurisdictions. Such variability and incomplete standardization of practice is particularly important when the organ is resuscitated in situ using normothermic regional perfusion.
"The International Society of Heart and Lung Transplantation has recently provided a framework within which donation after cardiac death, with or without the use of NRP, can be conducted to comply with ethical and legal norms and regulations, acknowledging that such norms and regulations may differ between societies," he writes. "To advance the field, and to ensure ongoing trust in the transplantation system, it is of critical importance that such discussions are held publicly and transparently."
More "Dry Runs"
Philip J. Spencer, MD, a cardiovascular and transplant surgeon at Mayo Clinic in Rochester, Minnesota, told theheart.org | Medscape Cardiology, "Donor heart allographs are safe for our patients with heart failure if procured and transplanted in an organized and protocolized manner. As the techniques are adopted globally, our patients will benefit."
Nevertheless, like D'Alessandro, he noted that procurement of DCD hearts is more labor-intensive. "A program and its patients must be willing to accept a higher number of 'dry runs,' which occurs when the team is sent for an organ and the donor does not progress to circulatory death in a time and manner appropriate for safe organ recovery.
"There is no doubt that being open to these organs will increase the patient's chances of receiving a donor heart in a shorter period of time," he said. "However, the experience of a dry run, or multiple, can be emotionally and financially stressful for the patient and the program."
No commercial funding or relevant conflicts of interest were disclosed.
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Cite this: Similar Outcomes With Hearts Donated After Circulatory Death - Medscape - Sep 29, 2022.