Mayo doctors hope to buy time for babies with underdeveloped hearts.
ROCHESTER – Every year, about 1,000 babies are born in the United States with half a heart — a rare defect that requires a series of risky surgeries and, even then, leaves the infants with a strong likelihood that their hearts will wear out prematurely.
Now, the Mayo Clinic has received federal approval for a first-of-its kind clinical study to see if stem cells from the babies’ own umbilical cords can strengthen their underdeveloped hearts and extend their lives.
If it works, the new technique could buy these children time as scientists scramble for a cure for the congenital defect called hypoplastic left heart syndrome (HLHS).
The Mayo study, which will begin as soon as 10 eligible candidates can be enrolled, could also pave the way for additional breakthroughs in stem cell treatments that would help the 19,000 children born each year with other heart defects. But for the time being, the doctors at Mayo are keeping their focus on those babies who need the most help now.
“We are not here to build an academic career out of science and technology,’’ said Dr. Timothy Nelson, director of Mayo’s HLHS research program. “We’re really here to make a difference in children’s lives who are living today with unmet needs.”
Christina DeShaw of Clive, Iowa, was pregnant with fraternal twins when she learned during an ultrasound procedure that the left side of her daughter’s heart was not developing properly.
“The world just started spinning,” DeShaw said. “Our lives were forever changed from that moment on.”
DeShaw and her husband, Brad Weitl, sought help from the Mayo Clinic for the baby they named Ava Grace.
They learned that children born with defects on the left side of the heart must undergo a series of three complex surgeries. The first is called the Norwood procedure: Within a few days of birth, surgeons reconstruct the heart so that the fully developed right ventricle can do both its own work of supplying blood to the lungs and the work of the defective left ventricle, which ordinarily would pump oxygenated blood back to the body.
Dr. Harold Burkhart, who is overseeing surgeries in Mayo’s new study, said that when the procedure was developed in 1983, only about 30 percent of the patients survived. About 70 percent survive now, he said, and at Mayo, about 9 out of 10 make it through.
The second and third surgeries are much safer. They involve rerouting blood from the body directly to the lungs, bypassing the heart entirely to reduce the workload of the right ventricle.
Ava Grace Weitl was born by Caesarean section on May 8, 2012, then whisked away for her first surgery. “Her heart was the size of a walnut,” DeShaw said. “She had less than a 40 percent chance of making it.”
Ava remained under intensive care until Labor Day. DeShaw, who works at ING Financial Partners in Des Moines, spent months living in a Rochester hotel; her husband, a construction estimator, drove up on weekends. But their trauma didn’t stop when they finally took their daughter home. Ava has suffered numerous complications and once had to be flown back to Mayo in a helicopter.
Unfortunately, Ava won’t be eligible for the stem cell trial: The design calls for stem cells to be injected into the right ventricle during the second surgery, and Ava has already had hers.
Still, Ava’s parents remain dedicated to helping with Mayo’s research. “We wanted to participate, not only because we thought that at some point Ava might benefit, but we also wanted to help all the other babies … and to try to give them the best shot,’’ DeShaw said.
Seeds of life
Cardiac stem cell treatments were pioneered in adult patients. Worldwide, some 5,000 to 6,000 people have received stem cell treatments for heart conditions, but those procedures relied on cells taken from the patients’ bone marrow, said Dr. Atta Behfar, one of Mayo’s leading researchers in the field.