Donor hearts from people who were COVID-positive appeared to be as safe for transplantation as those from people without the infection, according to a new analysis that includes data from the first 84 COVID-positive donor heart transplant recipients in the US.

The average hospital stay for those receiving a COVID-positive donor heart was 15 days, versus 17 days for patients receiving a heart from a donor without a respiratory infection.

"These findings suggest that we may be able to be more aggressive about accepting donors that are positive for COVID-19 when patients are in dire need of an organ for heart transplantation," said study author Samuel T. Kim from the David Geffen School of Medicine at University of California in Los Angeles.

The analysis is set to be presented at the American Heart Association's aScientific Sessions 2022' early next month.

"The pandemic made things worse with an increased rate of donors testing positive for COVID-19, which generally renders the donors unsuitable for transplantation," Kim said. "However, several academic centers have started to use COVID-positive donor hearts for heart transplantation in recent months and have reported good results."

The analysis found that both groups of donor organ recipients had similar rates of death in the hospital and 30 days after transplantation, as well as similar rates of complications such as graft failure (a condition where the body rejects the new organ) and lung complications.

Organ rejection occurred in 2.4 per cent of the recipients from COVID-positive donors, compared to 1 per cent of the others. Nearly 96.1 per cent of people who received hearts from COVID-19 positive donors survived the first 30 days compared to 97 per cent of those who received hearts from donors without the virus.

Among the four patients who died after receiving a heart from a COVID-positive donor, none died from respiratory causes or infections.

The researchers said they were surprised by the findings. "Specifically, we thought death from respiratory or lung-related causes would be a problem among recipients receiving donor hearts with COVID-19," Kim said. Yet, the researchers found no such differences.

"These findings provide evidence that outcomes were similar at 30-days post-transplant among patients who received COVID-19-positive donor hearts, so the potential risks appear to be lower than expected," said Eldrin F. Lewis, chair of the American Heart Association's Scientific Publishing Committee and an advanced heart failure and heart transplant specialist.