He got a new heart. Now the 34-year-old is fighting to fix the transplant system

The healthy young venture capitalist and tech entrepreneur thought he would get a workup, some medicine and be on his way. His pregnant wife waited in the car.

But within 20 minutes, Mace was on a ventilator, fighting for his life. His heart was failing. His lungs, liver and kidneys, deprived of blood, were shutting down.

Mace needed a heart transplant. His desperate condition catapulted him to the top of the transplant list, and he got a new heart in just over two days.

Three years later, Mace is a grateful 34-year-old father of two young boys and back to work as a venture capitalist. He is also leading a push to make the nation’s troubled organ-transplant system more equitable and efficient.

As he began his recovery, Mace and his wife, Jordan Mace, co-founded a nonprofit called Valeos that is building a database to help doctors, researchers and patients better identify who needs a transplant and keep recipients healthy. Nearly 104,000 people in the U.S. are waiting for transplants, mostly for kidneys. At least 17 die every day as they wait.

Better connections

The transplant system already gathers reams of data, but much resides with organizations whose data sets don’t talk to one another, said Tristan Mace. Valeos’s goal is to create a repository that automatically records and connects disparate data and makes it available to transplant centers across the nation, as well as researchers and others.

“It’s just in silos right now," said Mace, who created his first company, in website development, at age 14, followed by travel and retail-tech startups in his later teens and early 20s.

The nonprofit United Network for Organ Sharing developed and operates a national database under a federal government contract that includes data from transplant centers. The data are limited and adding variables requires several steps, said Dr. Stuart Sweet, Washington University pediatric pulmonologist at St. Louis Children’s Hospital.

Health systems caring for transplant recipients capture large amounts of data in electronic health records, but only a subset of it is incorporated into the UNOS database, said Sweet, a former board president of UNOS, who is now a board director at Valeos. Valeos’s repository could complement the existing database, he said.

The Maces are driven by a deadline and their impatience as tech-industry problem solvers: Tristan wants to see his infant and toddler boys grow up. While his transplant was a success, he has struggled with his health since receiving his new heart.

“I feel I don’t have much time," said Mace, who has been traveling around the country to meet transplant surgeons and potential funders. Meanwhile, he has undergone tests to find the cause of his latest health challenge: an abnormal white-blood-cell count.

Valeos, funded by donations and the Maces’ money, plans to launch its database in early 2025. More than 25 transplant centers, organ-procurement organizations and other entities have committed to share anonymized data on organ preservation, blood testing, dialysis and transportation. Valeos will operate the database, and the entities that supply data will have access to it, Mace said.

The nonprofit is building a “de-identified data sandbox," Mace said, through a collaboration with Oracle, which has provided 10 engineers and industry experts to help design it and has an executive on Valeos’s board.

The federal government is undertaking its own revamp of the sprawling organ-transplant system, beset for years with problems including long waiting lists. The Health Resources and Services Administration, which oversees the organ-transplant program, plans to replace sole management of the nation’s organ-transplant system—the Organ Procurement and Transplantation Network—with multiple vendors, as part of a 2023 law. UNOS has run the OPTN solo for nearly four decades.

Valeos is building its database separately. A revamp should include collecting more data on patients before they are on a waiting list and how they fare after a transplant, Mace said.

“They’re not looking at what immunosuppressant doses are people on? How do you combat rejection? What cancers do they end up with?" Mace said. “That data is so critical."

HRSA said strengthening data transparency is central to its overhaul and that it is improving pre-waitlist information. UNOS said it has advocated to remove barriers to collecting more complete transplant data.

The current national database “doesn’t require all the information that I would like to gather in order to better understand why one person may not survive on a waitlist," said Dr. Eileen Hsich, medical director for the Cleveland Clinic’s heart-transplant program. She has met Mace but isn’t working with Valeos. A national registry with more robust data would help provide better care and policies, she said.

Beating the odds

Mace is guided by his experience. Awaiting his transplant in February 2021, he was on a ventilator, a machine that circulated blood through his failing heart and lungs, a heart pump and dialysis.

“He is among the sickest people I’ve ever operated on," said Dr. Matthew Danter, surgical director of cardiac transplantation at the University of Kansas Medical Center.

Danter transplanted the heart of a deceased teenage boy into Mace after a first heart wasn’t a good match.

Mace learned that he had had a heart transplant when he woke up about a week later. He had heard of kidney and liver transplants, but “naively, I didn’t know that you could have a heart transplant," he said.

He and Jordan, who works in marketing technology, decided that night to form a nonprofit to help organ donors and recipients. “It’s not a community that you expect to be in until you’re in it and then you’re in it for life, and you want that system to work," said Jordan Mace.

Mace spent 48 days in the hospital—he had to be put on a ventilator again when his damaged lungs couldn’t take in enough oxygen—and eight months in outpatient rehab. He had to relearn how to speak, swallow and wiggle his toes.

Mace has had both hips replaced since then because of side effects of his medications. His gallbladder had to be removed. He takes 23 drugs. Now he has fatigue and nightly chills along with an abnormal white-blood-cell count.

He may eventually need another transplant of a heart or another organ.

The hardest part perhaps, he said, is that the Maces had to re-establish their relationship. Tristan lost his memory of five years before the transplant after his damaged lungs deprived his brain of oxygen. He no longer remembers getting engaged and married or moving from New York City to Jordan’s hometown.

He hopes Valeos can help him and other patients live longer, healthier lives.

“I don’t know if I will fully see that get realized with the time I have left," he said. “But I know what it is capable of doing and doing for other patients."