More than 100,000 people in the United States are sick enough to benefit from a heart transplant. In 2017, only 3,244 people actually received one.

The number of people in need of a heart transplant is growing, and the number of heart transplants performed each year is growing as well. Donations, however, have reached a plateau.

In two new Stanford University-led studies, researchers say the number of people on the waiting list could be reduced by using hearts that transplant centers often overlook, such as those organs that once belonged to people who were obese or who had an active hepatitis C infection.

No Difference in Survival Rates among Patients Receiving Hearts from Donors with Hepatitis C

In a new study published in American Heart Association’s journal Circulation: Heart Failure, researchers investigated the current use of hearts from donors with hepatitis C. Using information queried from United Network for Organ Sharing registry, they analyzed data spanning 2014 to 2017 on 1,306 heart donors with hepatitis C.

They found that only 5 percent of these hearts were used in transplants, yet there were no difference in recipient survival within the first year of transplant when compared with patients receiving hearts from donors without the disease. Longer-term studies could confirm whether these positive results persist over time.

The number of donors with hepatitis C has increased steadily since 2014, as have the number of deaths associated with opioid drug overdoses. The sharing of needles among heroin addicts contributes to the spread of hepatitis C infections.

The opioid epidemic predominantly affects young adults, so the average age of heart donors who test positive for hepatitis C has dropped from 47 to 35 in the last five years. These younger donors typically have fewer health problems, such as high blood pressure or diabetes, than do their older counterparts. If not for the hepatitis C, these donors would be “incredibly viable,” according to lead study author Yasbanoo Moayedi.

Positive Outcomes for Recipients of Hearts from Overweight or Obese Donors

In a separate study, researchers found a similar positive outcome for recipients of hearts from obese donors. Despite little evidence supporting the idea that these grafts are inferior, many transplant centers reject the hearts of obese donors.

Because of the high prevalence of obesity in the U.S., transplant centers may not have the option to reject organs from these donors in the future. About one-third of adults in the U.S. are currently obese, according to the Centers for Disease Control and Prevention (CDC), and the number of obese adults continues to rise.

The researchers in this study used the UNOS registry as well, examining data on 31,920 adults who had received heart transplants from 2001 through 2016. They classified the donors into four categories, based on the donor’s body mass index (BMI).

About 41 percent of recipients received a heart from donors of normal BMI. About 35 percent of the other patients received hearts from donors whose BMIs classified them as overweight, 15 received hearts from obese donors, and about 9 percent received hearts from donors classified as extremely obese.

There was no significant difference in overall survival among the four groups.

Using hearts from unusual donors, such as those with hepatitis C or who are obese, presents a tremendous opportunity to increase the number of heart transplants to the thousands of patients awaiting them.