BOSTON — A retired New Hampshire grocery store manager who once believed he was staring death in the face has become the longest-surviving recipient of a pig kidney transplant, living 271 days without dialysis before ultimately receiving a human kidney earlier this year, according to findings published Thursday in The Lancet medical journal.

Tim Andrews, 68, of Barrington, New Hampshire, first began discussing the experimental procedure with doctors in late 2024, when he was suffering from end-stage kidney failure and believed his time was running out.

“I didn’t think I was going to live through it, to be honest. But I wanted to do it for humanity,” Andrews told NBC News.

Andrews said the weight of his diagnosis prompted a moment of reflection that ultimately convinced him to pursue the experimental transplant, even without confidence he would survive it.

“I realized, OK, I’m a dead man. I’m a dead man walking,” Andrews said. “So I said to myself, ‘What have I done? What have I done with my life? This is an opportunity for me to do something that most people don’t get an opportunity to do, and that’s to help humanity.’”

Andrews said he was candid with Dr. Leonardo Riella, director of kidney transplantation at Massachusetts General Hospital and the study’s lead author, about his motivations heading into the procedure.

“This is about learning something. I don’t care if I die, as long as you learn one thing,” Andrews recalled telling Riella.

Andrews received the pig kidney transplant on Jan. 25, 2025, at age 66, through Mass General Brigham in Boston, making him part of an ongoing clinical trial examining the safety and viability of xenotransplantation, the transplantation of living organs between different species. Over the following 271 days, Andrews required no dialysis before ultimately receiving a human kidney transplant, according to a statement from Massachusetts General Hospital.

The hospital described the milestone as unprecedented for this type of procedure.

“His case represents the longest dialysis-free survival following porcine kidney xenotransplantation in a living human and the first transition to human kidney transplantation,” Massachusetts General Hospital said in its statement.

Since receiving the human donor kidney, Andrews said his recovery has exceeded his expectations, offering him a dramatically extended life expectancy compared with where he stood a year and a half earlier.

“We could be talking decades,” said Andrews, a father of three adult children ranging in age from 40 to 46. “It’s running perfect. I mean, the thing is perfect.”

Andrews said the experience of nearly losing his life has left him with a renewed appreciation for everyday moments he previously took for granted, including simple pleasures like smelling flowers, swimming, riding a bike and fishing.

“Every day I wake up, I’m like, this is another extra day because I should have been dead a year ago or more,” Andrews said.

Andrews said he knows little about the donor of his human kidney, aside from the fact that the donor was a young man who enjoyed blueberries, a fruit Andrews said he had never particularly cared for during the first six decades of his own life but has since developed an unexpected fondness for. Reflecting on the donor’s death, Andrews grew emotional discussing the weight of having received the organ.

“To know that somebody died way younger and I’m living because of it, that’s pretty tough,” Andrews said, his voice trailing off. “I have this new kidney in me and I need to honor it.”

Riella, who has led Mass General’s broader xenotransplantation research effort, said the underlying motivation behind the research remains addressing a persistent and severe shortage of available human donor organs.

“The organ shortage is the greatest crisis we have right now in transplantation,” Riella wrote in comments accompanying the study’s publication. “We know that the best treatment option for patients with end-stage kidney disease who have developed renal failure is transplantation, but we simply don’t have enough human organs to transplant in a timely manner.”

More than 100,000 people currently sit on the national organ transplant waiting list in the United States, with the vast majority of those patients waiting specifically for a kidney, according to figures cited by NBC News.

Andrews’ case builds on earlier progress in the field. Towana Looney, 55, previously lived with a pig kidney for what was then a record 130 days before her body began rejecting the organ, requiring its removal in April 2025. Looney remains alive and on dialysis while she awaits a matching human donor, according to a representative for NYU Langone Health.

Riella described the broader vision behind the research as using pig kidneys primarily as a temporary bridge for patients awaiting a compatible human donor organ, rather than necessarily as a permanent, standalone replacement.

“Our vision is that xenotransplantation could help address this gap — initially as a bridge to get patients off dialysis while they wait for a human donor kidney, and potentially, as we establish long-term safety and durability, as a destination therapy in its own right,” Riella said.

Andrews said his own conversations with Riella and the broader research team have reflected a rapidly shifting timeline for when the procedure might become more widely available to patients facing similar circumstances.

“When we talked the first time and I met Dr. Riella, they were talking about at least 10 years, that it’s going to be at least 10 years before this becomes viable — now they’re talking about five years or less than five years,” Andrews said, adding that he believes he “may live to see it” become a routine medical procedure.

Andrews’ successful outcome follows Mass General’s first pig-to-human kidney transplant in 2024, performed on patient Richard “Rick” Slayman, who survived 52 days before dying of cardiac causes the hospital said were unrelated to the transplant itself, with his pig kidney reportedly still functioning at the time of his death.

Andrews said learning about Slayman’s case before his own procedure gave him a measure of cautious optimism heading into his own transplant.

“I read about it and they told me he died, but he died of other causes, the kidney was still working,” Andrews said. “I said, ‘Huh, you know what? I think this might work.’”