New research shows that there is no benefit from the common practice of using levothyroxine to preserve function of potential donor hearts.
The multicenter randomized placebo-controlled trial found that intravenous levothyroxine administration in hemodynamically unstable brain-dead donors did not improve the rate of heart transplantation or graft survival.
"This practice has been adopted by multiple organ-procurement organizations (OPOs) and is used on thousands of organ donors each year, without ever having been rigorously studied. It turns out that it doesn't have any benefit and may cause some harm," first author Raj Dhar, MD, a professor of neurology at Washington University School of Medicine, St Louis, Missouri, said in news release.
"Based on the results, we are already seeing practice change in some of our participating sites who had been using thyroid hormone and now are not," Dhar told theheart.org | Medscape Cardiology.
The study was published online November 29 in The New England Journal of Medicine.
Definitive Data, Major Implications
In a linked editorial, Kiran Khush, MD, with Stanford University School of Medicine, California, said that the study provides, "the most definitive data to date about donor thyroid hormone replacement therapy."
The results have "major clinical implications" for OPOs, with nearly half of these organizations in the United States routinely administering thyroid hormone during donor care, Khush added.
The trial was conducted at 15 OPOs in the United States and included 838 hemodynamically unstable brain-dead donors who were being considered for heart donation.
Within 24 hours after declaration of brain death, half of the donors were randomly allocated to levothyroxine (30 μg/h for a minimum of 12 hours) and half to normal saline.
Transplantation of the donor heart, the primary outcome, occurred in 230 donors (54.9%) in the levothyroxine group and in 223 donors (53.2%) in the saline group, a nonsignificant difference (adjusted risk ratio, 1.01; 95% CI, 0.97-1.07; P = .57).
There was also no substantial between-group difference in 30-day graft survival, which occurred in 224 hearts (97.4%) transplanted from donors given levothyroxine and 213 hearts (95.5%) transplanted from donors given saline (difference, 1.9 percentage points; 95% CI, -2.3 to 6.0; P < .001 for noninferiority at a margin of 6 percentage points).
In addition, neither weaning from vasopressor therapy nor ejection fraction on echocardiography was better with levothyroxine than with saline, "findings that suggest a lack of physiological benefit of levothyroxine on donor cardiovascular function," the authors note in their article.
In post hoc analysis, the lack of treatment effect was consistent in subgroups defined according to baseline free T4 level, vasopressor dose at baseline, and donor cause of death.
"The overarching goal of donor care is to improve the quality and quantity of organs for transplantation. A key challenge is to counteract the physiological perturbations that occur in the context of brain death and contribute to cardiac dysfunction and hemodynamic instability, the authors note.
"Hormonal resuscitation, including with levothyroxine, is broadly espoused by donor-care guidelines to assist with hemodynamic stabilization and increase the number of organs transplanted, a practice supported only by observational data," they add.
In this randomized placebo-controlled trial, "we found good evidence that this intervention we've been using for 40 years doesn't work," Dhar said in the news release.
"It's vital that we explore questions like this to ensure we are doing all we can for patients who need organs — and to ensure that they receive the most benefit possible from the generous people who choose to donate organs," he added.
Funding for the study was provided by Mid-America Transplant. Dhar is a consultant for Mid-America Transplant and Marinus Pharmaceuticals. Khush is a consultant for the Scientific Registry for Transplant Recipients (SRTR).
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Cite this: No Benefit of Levothyroxine in Heart Donors - Medscape - Dec 04, 2023.
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