Severe Donor Obesity Does Not Worsen Heart-Transplant Outcomes

By Reuters Staff

September 23, 2020

NEW YORK (Reuters Health) - Transplantation of hearts from severely obese donors is not associated with worse post-transplant outcomes than when hearts from slimmer people are used, according to a study of United Network for Organ Sharing (UNOS) data.

Many heart-transplant centers use weight-based criteria to exclude underweight and overweight donors, but recent evaluations have suggested similar outcomes in heart transplants from mildly obese and overweight donors versus normal-weight donors.

To investigate, Dr. Leora T. Yarboro and colleagues of the University of Virginia Health System, in Charlottesville, used data from UNOS Standard Transplant Analysis and Research files.

Of the more than 26,000 transplants evaluated, 3.5% had donors with a BMI of 40 or higher. Donors with such severe obesity were older, had a greater prevalence of comorbidities, and were more likely female, compared with other heart-transplant donors.

Recipients of these transplants had a greater median BMI and were more likely to have diabetes and be on life support at the time of transplant compared with other heart-transplant recipients.

Two-thirds of transplants from donors with severe obesity were size mismatched (donor weight >130% of recipient weight), compared with only 9.8% of transplants from donors without severe obesity; none were undersized (donor weight <70% of recipient weight), compared with 3.2% of transplants from donors without severe obesity.

Rates of acute rejection, pacemaker need, and dialysis requirement were similar between recipients of organs from severely obese donors and those without severe obesity, respectively, the researchers report in Circulation: Heart Failure.

Both groups' recipients also had similar rates of graft failure at one year, one-year survival and overall graft failure from atherosclerosis.

In adjusted analyses, donor severe obesity was not associated with significant differences in long-term survival (hazard ratio, 0.928; P=0.30). Moreover, obesity-related comorbidities of the donor were not associated with an increase in mortality, whereas obesity-related comorbidities of the recipient were.

Neither oversized nor undersized donor heart was associated with increased mortality.

Only 19.5% of hearts from potential donors with severe obesity were ultimately transplanted, compared with 31.6% of hearts from potential donors without severe obesity.

"As the population of potential organ donors becomes increasingly obese, increased utilization of hearts from obese and even severely obese donors could increase the critically low donor pool," the authors conclude. "Existing paradigms limiting heart transplants from oversized and severely obese donors should be reevaluated to ensure maximum utilization of donor organs and improve outcomes for the growing list of patients with end-stage heart failure."

Dr. Yarboro did not respond to a request for comments.

SOURCE: Circulation: Heart Failure, online September 16, 2020.