Medical Technology

Donor Hearts Following Circulatory Death: Possible, a Vital Resource

Hearts transplanted after donor circulatory death fare just as well as those procured after brain death and benefit the recipients similarly, suggests a comparison of the two procurement strategies in data from the United States, most collected during the COVID-19 pandemic’s first year.

Injury from transient “warm” ischemia is less likely in hearts obtained from donors after brain death (DBD), a strategy that is far more common in the United States than transplantation involving hearts from donors after circulatory death (DCD), observe researchers writing this week in the Journal of the American College of Cardiology.

But results using the two strategies can be similar when both donor and recipient are carefully selected, the group concludes based on their analysis of United Network for Organ Sharing (UNOS) data.

The study covered transplant outcomes only at 30 days and 6 months, and so says little about longer-term transplantation success. Still, DCD and DBD procedures were similar for recipient all-cause mortality and risk of primary graft failure, stroke, hemodialysis, and other outcomes, and for hospital length of stay.

“Now that we have shown that DCD heart transplantations using these types of donors are feasible and have good outcomes, heart transplantation centers will gradually begin to broaden their DCD-donor acceptance criteria,” lead author Shivank Madan, MD, MHA, Montefiore Medical Center/Albert Einstein College of Medicine, New York City, told theheart.org | Medscape Cardiology.

Adult DCD donor referrals have “consistently increased over the past decade,” the researchers note in their report. Were all such potential donors to be echocardiographically screened, the strategy’s “broad acceptance and utilization” could lead to “almost approximately 300 additional adult heart transplantations in the United States annually,” the group estimates.

Their analysis also points to potential DCD heart donor and recipient selection criteria that would promote good results. For example, DCD hearts that were transplanted into patients — compared with those ultimately not transplanted — were from younger and more likely male donors with an ostensibly more favorable risk profile.

Similarly, the DCD hearts overall— compared with those from donors after brain death — were from younger donors who tended to be men. They also more often went into patients on durable left-ventricular assist device (LVAD) support, those likely to have type O blood, and those with lower priority on the UNOS wait list.

Listing times for a DBD heart are typically long for such patients, Madan observed, so “it is quite possible that heart transplantation centers are using this new opportunity of DCD donors as a way to reduce waitlist times for their patients.”

Such hearts in the analysis tended to have lower risk features, probably because DCD transplantation “is a new emerging practice area in the US, so heart transplantation centers are expected to be more cautious.” Also, he said, DBD hearts are “more likely to tolerate the ‘mandatory warm ischemia’ that occurs during the procurement of hearts from DCD donors.”

The current analysis “provides further data to support this approach as a crucial strategy to expand the donor heart pool,” writes Francis D. Pagani, MD, PhD, University of Michigan, Ann Arbor, in an accompanying editorial.

“The criteria for selection of DCD heart donors appear quite restrictive” compared with those applied to DBD hearts, he agrees. “This approach is obviously prudent with the initiation of any new clinical therapy, and with continuing clinical experience, relaxation of donor criteria of the DCD pool will occur, and numbers of donors will likely expand.”

A total of 136 DCD hearts from among 3611 adult potential DCD donors in the UNOS registry referred from January 2020–February 2021 were used for transplantation. The 136 DCD donors, compared with the potential DCD donors whose hearts were not transplanted, were more likely (P < .001) to be:

  • Younger (median age 29 vs 47 years)

  • Male (34.6% vs 10.3%)

  • Blood type O (79.4% vs 46.7%)

  • Without a history of smoking (10.4% vs 28.8%)

  • Without histories of diabetes (2.2% vs 12.9%), hypertension (12.5% vs 41.5%), or coronary artery disease (0% vs 7.8%)

Compared with 2961 adult DBD donors undergoing heart-only transplantations with available follow-up data, the DCD transplant donors were (P < .05) 

  • Younger (median age 29 vs 32)

  • Less likely to be female (11% vs 28.7%)

  • Subjected to longer total ischemic times (median 5.9 hours vs 3.4 hours).

Estimated 30-day and 6-month survival for the overall DCD and DBD cohorts were not significantly different, at 96.8% and 92.5%, respectively. Nor were there significant differences in 30-day primary graft failure risk or rates of in-hospital stroke, need for pacemaker or hemodialysis, or hospital length of stay after transplantation.

The COVID-19 pandemic during the period covered by the study “severely affected organ procurement organizations and transplant programs across the country,” Madan noted. Even in normal times, DCD heart transplantation is much more resource intensive than DBD procedures with current protocols, so “it is actually quite remarkable what the field of heart transplantation as a whole was able to achieve during the current pandemic.”

Moreover, “we believe that the estimate of 300 additional DCD heart transplantations annually — or about 10% of the annual adult heart transplantation volume in the US,” based on the current analysis — “is likely a very conservative estimate,” Madan said.

“As we move past the pandemic and transplant centers become more comfortable with the technique of DCD heart-transplantations, this number should be significantly higher.”

Madan and colleagues have disclosed no relevant financial relationships. Pagani discloses serving as a scientific advisor for FineHeart and CH Biomedical and being a Data Safety Monitoring Board member for Carmat and the National Institutes of Health PumpKIN trial.

J Am Coll Cardiol. Published online January 10, 2022. Abstract, Editorial

Follow Steve Stiles on Twitter: @SteveStiles2. For more from theheart.org | Medscape Cardiology, follow us on Twitter and Facebook.

Content Source: https://www.medscape.com/viewarticle/966614?src=rss

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