Maryland: The first person in the world to get a heart transplant from a genetically-modified pig has died, the Maryland hospital that performed the surgery announced on Wednesday.

David Bennett, 57, who received the modified pig heart, died Tuesday at the University of Maryland Medical Centre. Doctors didn’t give the exact cause of death, saying only that his condition had begun deteriorating several days earlier.

David, who had terminal heart disease, survived for two months following the surgery in the US. He had already been bedridden for six weeks leading up to the surgery, attached to a machine which was keeping him alive. Bennett's son praised the hospital for offering the last-ditch experiment, saying the family hoped it would help further efforts to end the organ shortage.

Doctors for decades have sought to use animal organs one day for life-saving transplants. Bennett, a handyman from Hagerstown, Maryland, was a candidate for this newest attempt only because he otherwise faced certain death - ineligible for a human heart transplant, bedridden and on life support and out of other options.

Prior attempts at such transplants or xenotransplantation have failed largely because patients’ bodies rapidly rejected the animal organ. This time, the Maryland surgeons used a heart from a gene-edited pig: Scientists had modified the animal to remove pig genes that trigger the hyper-fast rejection and add human genes to help the body accept the organ.

At first the pig heart was functioning and the Maryland hospital issued periodic updates that Bennett seemed to be slowly recovering. Last month, the hospital released video of him watching the Super Bowl from his hospital bed while working with his physical therapist.

Bennett survived significantly longer with the gene-edited pig heart than one of the last milestones in xenotransplantation when Baby Fae, a dying California infant, lived 21 days with a baboon's heart in 1984.

"He proved to be a brave and noble patient who fought all the way to the end," surgeon Bartley Griffith, who performed the transplant, said in a statement released by the hospital.

Other transplant experts praised the Maryland team's landmark research and said Bennett's death shouldn't slow the push to figure out how to use animal organs to save human lives.

The need for another source of organs is huge. More than 41,000 transplants were performed in the U.S. last year, a record, including about 3,800 heart transplants. But more than 106,000 people remain on the national waiting list, thousands die every year before getting an organ and thousands more never even get added to the list, considered too much of a long shot.

Organ rejection, infections and other complications are risks for any transplant recipient. Experts hope that the Maryland team quickly publishes in a medical journal exactly how Bennett's body responded to the pig heart.

Pigs have long been used in human medicine, including pig skin grafts and implantation of pig heart valves. But transplanting entire organs is much more complex than using highly processed tissue. The gene-edited pigs used in these experiments were provided by Revivicor, a subsidiary of United Therapeutics, one of several biotech companies in the running to develop suitable pig organs for potential human transplant.