Reversal Seen in Use of Hearts From High-Risk Donors



SAN DIEGO – Transplantation physicians may be increasingly avoiding the use of hearts from donors who have high-risk characteristics, even as demand for transplantable hearts continues to outstrip supply, suggests a retrospective study of more than 42,000 heart transplant recipients.

The percentages of transplanted hearts from donors who have characteristics that are associated with an elevated risk of poor outcomes for the recipient (such as older age or hypertension) initially increased during the recent 2-decade study period. But thereafter, they plateaued or fell – in some cases to levels seen at the start of the period.

There are two possible explanations for the declining use of hearts from high-risk donors, lead investigator Dr. Jose N. Nativi told attendees of the annual meeting of the International Society for Heart and Lung Transplantation.

"One hypothesis is that there is a concern about adverse outcomes" for recipients who would be given these hearts, in the wake of publications describing actual experience with their use, he explained.

"The second hypothesis is that, probably, we have another option to offer these patients, that is, the increasing utilization of left ventricular assist devices," Dr. Nativi said. "So for a patient who is critically ill, instead of offering them a high-risk donor, now we have the luxury in some centers to offer them an alternative, that is, mechanical support."

There have been several key milestones in efforts to make more organs available for transplantation in the United States, according to Dr. Nativi, a fellow in cardiology with the University of Utah and the UTAH (Utah Transplantation Affiliated Hospitals) Cardiac Transplant Program in Salt Lake City.

The Crystal City Conference in 2001 resulted in a formal recommendation to expand the use of hearts from high-risk donors (Circulation 2002;106:836-41). And the Organ Donation Breakthrough Collaborative in 2003 encouraged increased consent and donation by people with high-risk features (Crit. Care Nurs. Q. 2008;31:190-210).

"These efforts are resulting in the expansion of acceptable donor criteria toward high-risk donors," he said. "But the high-risk donor still remains a matter of controversy."

In the year after the collaborative, there was an increase in the number of all types of organs donated – with the sole exception of hearts. "So we are still struggling to find donors for heart recipients," Dr. Nativi commented.

To assess temporal patterns in the use of hearts from high-risk donors, the investigators analyzed data from the U.S. Scientific Registry of Transplant Recipients, identifying adult patients who underwent single-organ heart transplantation in 1987-2009.

They were divided into three eras by transplantation date: era 1 (1987-1996), when standard donor criteria were used; era 2 (1997-2003), when there was increasing acceptance of the high-risk donor, and reports about the use of organs from such donors increased; and era 3 (2004-2009), after the collaborative was established.

Results were based on 42,023 patients who underwent transplantation during the study period (42% in era 1, 32% in era 2, and 26% in era 3), Dr. Nativi reported.

In multivariate analyses that included more than 40 donor characteristics as well as a transplant center’s patient volume, recipients were more likely to die in the first year post transplantation if their donor was older than 40 years of age (hazard ratio, 1.2), was female (HR, 1.2), had a cerebrovascular cause of death (HR, 1.6), or had a history of hypertension (HR,1.3).

Temporal trends showed a biphasic pattern for three of these high-risk characteristics, with the percentage of hearts having the characteristic increasing significantly between era 1 and era 2, but then decreasing significantly between era 2 and era 3.

For example, the percentage of hearts from donors older than 40 years averaged 21%, 30%, and 28% in eras 1, 2, and 3, respectively. The pattern was similar for hearts from donors who were female (29%, 31%, and 27%) and those having a cerebrovascular cause of death (26%, 29%, and 23%).

The percentage of hearts from donors having hypertension increased from 4% to 11% between eras 1 and 2, and again from 11% to 13% between eras 2 and 3. But in clinical terms, the latter change was really more of a plateau, according to Dr. Nativi.

He acknowledged that factors other than physicians’ decision to avoid the use of hearts from high-risk donors may have contributed to the observed trends. For example, "changes in donor characteristics may have been affected by a potentially changing donor pool," but that possibility is more difficult to study, he said.

Dr. Nativi reported that he had no relevant financial disclosures.

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