Long-standing hormonal treatment for donated hearts has proven ineffective or even harmful

Doctors who care for deceased organ donors routinely treat the donor bodies with thyroid hormones in an effort to preserve heart function and increase the quantity and quality of hearts and other organs available for transplantation. However, according to a recent clinical trial led by researchers at Washington University School of Medicine in St. Louis and Mid-America Transplant in St. Louis, routine thyroid hormone intervention does not is not effective in achieving these goals and may even cause harm.

The study is published November 30 in The New England Journal of Medicine.

“There have been very few studies of what actually works in terms of preserving organ function for donation – and with a shortage of organ donors for transplantation, it is essential that we do everything we can to preserve organs and save lives with them,” said Raj Dhar. , MD, professor of neurology at the University of Washington and attending physician in the Neurology/Neurosurgery Intensive Care Unit at Barnes-Jewish Hospital. Dhar is the corresponding author of the article and led the clinical trial with Gary Marklin, MD, medical and research director at Mid-America Transplant, the St. Louis region’s organ procurement organization.

“We decided to study whether intravenous thyroid hormone would lead to more heart transplants,” Dhar said. “This practice has been adopted by several organ procurement organizations and is used on thousands of organ donors each year, without ever having been rigorously studied. It appears to have no benefit and may cause harm. Our results tell us we should end this practice.

When patients are declared dead according to neurological criteria, their organs can be donated for transplantation with the consent of the deceased or their relatives. Deceased donors can provide up to eight organs, if all are in good condition. It can take up to 72 hours from the time of death to the start of the transplant.

Meanwhile, doctors like Dhar and Marklin work to keep donor hearts beating as normally as possible to preserve the health of the heart and other organs. But despite doctors’ best efforts, about half of these hearts deteriorate and are unsuitable for transplantation when the time comes.

Previous observational studies have suggested that administering thyroid hormones to deceased donors may increase the viability of the heart. Thyroid hormones influence the strength and speed of the heartbeat, and hormone levels can drop once the brain stops working.

At the same time, some doctors worry that treating donor hearts with intravenous thyroid hormones could increase the risk of a rapid heart rate and high blood pressure, which could injure other organs and make them less suited to transplantation. Despite these concerns and the lack of definitive evidence supporting this practice, hormone supplementation for deceased organ donors has become the norm.

“I have always been skeptical of the benefits of thyroid hormone in donor management based on its physiology and previously published studies. This is why we have not used levothyroxine to treat our donors during the transplant to Central America,” Marklin said. To date, Mid-America Transplant has cared for more than 2,700 deceased organ donors at its independent organ procurement center, more than any other organ procurement organization in the country.

“But because more than 70 percent of organ procurement organizations use thyroid hormones, Dr. Dhar and I felt we needed to do a definitive study to answer this important question: whether to give thyroid hormones to “Do organ donors preserve heart function and produce more hearts available for transplantation?” Marklin continued.

“It is very unusual to have a study of deceased organ donors of this size and with such rigor, but we believed the four-year multicenter research was essential to definitively answer this key question and enable better management of organ donors.”

Dhar and Marklin assembled a team at 15 organ procurement organizations across the country, including Mid-America Transplant. With research authorization provided by their families, 838 organ donors declared dead according to neurological criteria were recruited. Half were randomly selected to receive levothyroxine in the first 24 hours, while the others received saline. Levothyroxine is a synthetic form of the human thyroid hormone T4, commonly used to treat hypothyroidism.

The study was not blinded so that organ recipients could be fully informed about the hearts they were about to receive. Each organ procurement organization followed its own standard donor care and organ allocation protocols for all donors enrolled in the study.

Thyroid hormone treatment made no significant difference in the number of hearts successfully transplanted. Just over half of the hearts in each group were suitable for transplantation: 230 (54.9%) in the thyroid hormone group and 223 (53.2%) in the placebo group. Of the 453 transplanted hearts, 97.4% of hearts from thyroid hormone-treated donors and 95.5% of hearts from placebo-treated donors were still functioning well for the recipients after 30 days. This small difference was not statistically significant.

Additionally, thyroid hormones were more likely to cause high blood pressure and increased heart rate before donation. These side effects became less severe or disappeared when hormone doses were reduced or discontinued in the thyroid hormone group, indicating that the hormone may cause temporary overstimulation of the heart in addition to having little or no no effect on the effectiveness of heart transplantation.

“We found strong evidence that this intervention that we’ve been using for 40 years doesn’t work,” Dhar said. “It is essential that we explore issues like this to ensure we are doing everything we can for patients who need organs and to ensure they receive the most benefit possible from the generous people who choose to donate their organs.”

After seeing the results, several organ procurement organizations stopped using thyroid hormones in treating organ donors, Dhar said.