Study: Gender plays role in success of heart transplants

Los Angeles Times

Heart transplant patients are as much as 25 percent more likely to survive if the sex of the donor is the same as the patient’s, researchers said Wednesday.

The results surprised experts because, for most types of transplants, sex differences are not relevant as long as a good immuno-compatability is achieved.

The worst results were in men who received hearts from smaller women, suggesting that the pumping capacity of the organ is crucial to the success of the procedure, according to the study, presented at a New Orleans conference of the American Heart Association.

But women were also somewhat more likely to reject a male organ, perhaps because of lingering immune stimulation from earlier pregnancies, experts said.

The findings might not make much difference to transplant procedures.

“Organs are scarce ... so we must take the next organ that is available,” said Dr. Jon Kobashigawa, director of the heart transplant program at the Ronald Reagan University of California, Los Angeles, Medical Center.

About 2,200 heart transplants are performed each year, with another 2,700 patients on waiting lists for a heart, according to the United Network for Organ Sharing, or UNOS, which manages the waiting lists. Three-quarters of all heart transplants are given to men, so by necessity many must receive female organs.

Dr. Eric Weiss of Johns Hopkins University in Baltimore studied UNOS records for 18,240 heart transplants that took place between 1998 and 2007. Some patients were followed for as long as 10 years, with the average being 3.4 years.

Overall, 71 percent of the patients -- 77 percent of males and 51 percent of females -- in the federally funded study received a heart from a donor of the same sex. About a quarter of the patients died during the study.

When the sexes of the donor and recipient matched, the researchers observed:

-- a 13 percent lower risk of graft rejection in the first year.

-- a 14 percent lower risk of rejection over the length of the study.

-- a 25 percent drop in death during the first 30 days after transplant.

-- a 20 percent lower rate of death in the first year.

“We hypothesized that we would see a big difference in the short-term survival -- which we did, most likely because of heart-size issues -- but what was interesting was the substantial difference in the long term, as well,” Weiss said.

The results were similar to data on 8,000 patients from a study compiled by the International Society for Heart and Lung Transplantation, Kobashigawa said. In that study, however, all the patients were followed for at least 10 years.

The primary difference between the two studies was that among the international patients, women who received organs from women also did not do as well in the long term.