Disparities in donor acceptance rates point to need for more equitable heart transplant care

When a patient is going through end-stage heart failure, the best treatment is to get a heart transplant. The basic steps are familiar: First a patient gets on the waiting list, and then the wait begins for the offers. In recent years, access to donor hearts has gone up thanks to a change in heart allocation policy, but there are still gender- and race-based disparities in the acceptance rate of a donor heart offer by transplant teams, according to new research published Monday in the Journal of the American Medical Association. While both white and Black women were more likely to have an offered heart accepted by their transplant team, Black men had the longest wait for a transplant, as transplant centers repeatedly rejected offers. The high number of rejections may translate to a longer wait time and a higher waitlist mortality for Black men, some transplant experts say.

The findings, said first author Khadijah Breathett, were “really bizarre.” The number of matched offers until an accepted offer was much lower for women, especially white women, while they were greatest for Black men. For every offer that was made, the odds were significantly lower for Black individuals than white individuals that the offer would be accepted. Researchers said that the median number of offers was 11 for Black men, seven for Black women, nine for white men and five for white women.

The higher acceptance rate in women initially surprised Breathett, because there’s no reason why men should necessarily have a longer wait time. 

“I personally think it’s probably related to bias,” said Breathett, an advanced heart failure transplant cardiologist at Indiana University Health. She told STAT that maybe doctors think: ‘“Oh this woman, she can’t wait, we can’t wait. This works. Take it. Let’s go accept the heart,’ whereas for men maybe they think they’re more sturdy. ‘They can wait.”’ Different biases and structural racism may not be intentional, but they showcase the power of stereotypes in society and how they often impact decisions.

When a patient becomes a heart transplant candidate, they are matched through a standardized process. A computer algorithm ranks and matches candidates and donors based on a variety of characteristics like urgency, location of transplantation center, blood type, and location of the donor hospital. Then when a transplant center gets an offer, the next candidate in line is matched with a donor. The transplant team goes over the donor data and decides to accept or reject the organ. But while the matching process follows an algorithm, the transplant team’s decision to accept an offer is a little more subjective, taking into account special factors the doctors may weigh in deciding a donor heart’s suitability for their patient.

“Anyone who cares for patients with advanced heart failure, this study should give us pause and time for not only self-reflection but also reflection of how programs are run in particular as well as the whole process in general,” said Michelle Kittleson, an advanced heart failure transplant cardiologist and director of Heart Failure Research at the Smidt Heart Institute at Cedars-Sinai. She was not a part of the study, but commented that it was “beautiful” and well done. The United Network for Organ Sharing offers a wealth of data, Kittleson said, that can provide important signals and trends, and highlight unmet needs for patients with advanced heart failure.

In 2018, there was a change in heart transplant allocation policy, which prioritized the sickest patients. As a result, there was a significant increase in the number of hearts transplanted for all groups. And the wait time decreased from months to up to a month. This includes Black patients, who, despite being the least likely to receive a transplant, received 26% of all transplants in the U.S. in 2019, compared to just 5% in 1987. However, disparities are still common, with Black patients and women being less likely to receive a heart transplant than white patients and men. Black individuals also have a 50% higher likelihood of developing heart failure than white individuals.

Breathett and her colleagues reviewed UNOS datasets for the years 2018 to 2023, which reflected the changeover to the new allocation policy. They compared U.S. non-Hispanic Black and white patients.

During that period, 13,760 donor hearts were made available via 159,177 heart offers. There were 14,890 candidates listed for heart transplant — 30.9% of whom were Black, and 69.1% white, while 73.6% were men, and 26.4% were women.

When adjusted for different variables with patients, donors, and offer considerations, the Black candidates were 24% less likely to have the first offered heart accepted compared to a white candidate. Black candidates were still less likely to have an offer accepted up to the 16th offer compared to white candidates. And when considering gender, the odds of a female candidate to have an accepted offer was 53% higher. Women were also more likely to have an offer accepted by the sixth one compared to men.

Jaimin Trivedi, associate professor of cardiovascular and thoracic surgery at the University of Louisville, who was also not a part of the study, noted that when a patient receives an implanted medical device like a left ventricular assist device (LVAD), that lowers the priority for that patient, which might also contribute to a difference in offers. In the study, 32% of Black men had an LVAD compared to 26% of white men. And the percentages were lower in Black women (25%) and white women (17%).

Researchers who spoke with STAT generally thought that focusing on data after the implementation of the new allocation system was smart, so that the impact of the new system, which prioritizes the sickest patients who need mechanical support devices like ECMO (extracorporeal membrane oxygenation) could be assessed. “Unfortunately, what that might mean is that higher-income areas, which are the areas that can offer patients devices like ECMO, seem to get more hearts,”said Asishana Osho, an advanced transplant cardiologist at Massachusetts General Hospital.

According to the study authors, more investigation is needed to change the decision-making that might be contributing to these disparities.

“I don’t think we’ve proven that African Americans are getting worse care than others or that men are getting worse care than women. I don’t think we can conclude that. But we do see concerning disparities for which we don’t have a clear reason,” said Paul Heidenreich, a non-invasive cardiologist, professor, and vice chair for quality at Stanford University, who co-wrote an editorial in JAMA to accompany the study. 

In terms of limitations, the researchers mention that there were no adjustments made for donor data, like the quality of the heart or if there was a presence or absence of coronary artery disease. Trivedi and Heidenreich both agree that including information about body mass index and blood type would have been helpful additions to analyze the rate of heart offer acceptance. 

Moving forward, Breathett said that transplant centers need to get more data on how they are accepting donors or not accepting donors based on race, ethnicity, and sex and look for patterns. It’s possible that some centers are rejecting offers with an eye toward their own statistics. “Meaning, maybe some people of color won’t get a transplant because they’re trying to mitigate a bad outcome and prevent being penalized,” Breathett said. It’s important, said Kittleson, that the centers take a “deeper dive … with an open mind for all potential sources of biology and disparity, then enact the changes so there is more equity in the process.”