A group of pediatric surgeons at the School of Medicine used a four-year-old girl’s bone marrow to repair her heart in what could be the newest advance in the field of regenerative medicine, the Wall Street Journal reported Wednesday.

The patient, Angela Irizarry, was born with a single pumping chamber in her heart — a potentially lethal defect known as hypoplastic left heart syndorome.

The Yale doctors trained Angela’s body to grow new cells that function like a normal blood vessel by implanting a bioabsorbable tube in her chest, which was seeded with stem cells from her bone marrow. Six months after Angela’s surgery, the tube disappeared with the cells, and her body induced regeneration.

“We’re making a blood vessel where there wasn’t one,” Chris Breuer, an associate professor of surgery leading the operation, told the Wall Street Journal.

Breuer said he expects to implant a tissue-engineered blood vessel in a second patient soon as part of a study to test the safety of the procedure and determine whether the blood vessels grow as the child gets older. He said he hopes that the procedure, if successful, will be available under a special U.S. Food and Drug Administration humanitarian device exemption.

Irizarry’s heart defect affects about 3,000 newborns in the U.S. each year. Without surgery, seventy percent of these infants die before their first birthday.