Doctors in Maryland accomplished a medical first after a man got a heart transplant from a genetically modified pig.

After three days, the man is doing well on Monday without any reported complications. The surgery took nine hours. The heart came from a 240-pound gene-edited pig.

Dave Bennett, 57, was facing death before the operation at the University of Maryland Medical Center. His long-term chances of survival remain unclear and Bennet was aware there were no guarantees after the experimental procedure. 

“It was either die or do this transplant. I want to live. I know it’s a shot in the dark, but it’s my last choice,” Bennett said a day before his surgery, according to a statement from the University of Maryland School of Medicine.

“I look forward to getting out of bed after I recover,” he said.

The procedure was approved by the Food and Drug Administration. The agency allowed an emergency authorization of “xenotransplantation experiments ” for “compassionate use.”

The procedure comes after New York University researchers in September attached a pig's kidney to a deceased human body to study the effects. Pigs have similar organs to humans.

"This is a truly remarkable breakthrough," Dr. Robert Montgomery, who lead the NYU study, said about the recent heart transplant. "I am thrilled by this news and the hope it gives to my family and other patients who will eventually be saved by this breakthrough."

There are currently about 106,657 people on the national transplant waiting list. Medical experts believe this could be a major advancement for those seeking a transplant.

“If this works, there will be an endless supply of these organs for patients who are suffering,” said Dr. Muhammad Mohiuddin, scientific director of the university’s animal-to-human transplant program, according to the Associated Press.