Three Strikes, Three Procedures Save Girl With Half A Heart

Traditional surgery was too risky for Mira because of other health factors, but doctors used a combination of less invasive procedures to give her new life.

Two-week old Mira Larrison is going home to Mio, Mich. this week after undergoing a series of procedures, both as a fetus and immediately after birth at the University of Michigan Health System, to treat children born with half a heart.

One in 100 children born in the United States has a heart defect, and the U-M Congenital Heart Center is a Center of Excellence for treating one of the most complex ones, hypoplastic left heart syndrome.

The condition is often described as being born with half a heart because the left ventricle is underdeveloped. Traditional surgery was too risky for Mira who had other health challenges. Instead U-M used a combination of a fetal intervention, followed by hybrid procedures, which are less invasive than open heart surgery, to treat the heart defect.

U-M is one of the first hospitals in the country to use the combination to care for such a high-risk patient.

“Additional surgeries are in Mira’s future, but she’s passed incredible milestones,” says Aimee K. Armstrong, M.D., an interventional cardiologist and Assistant Professor in the Department of Pediatrics and Communicable Diseases at the U-M Medical School.

What is hypoplastic left heart syndrome?

Mira’s parents Katie and Jeremy Larrison knew their second child would face challenges at birth. An ultrasound at 18 weeks showed the poor heart function and underdevelopment characteristic of HLHS.

Babies with HLHS cannot pump enough oxygen-rich blood to meet the body's needs. Without treatment, 95 percent of babies die within one month. It is treated either by a heart transplant or a series of three heart surgeries, beginning at birth with what’s called the Norwood procedure. The surgeries are required to allow the right side of the heart to do the work of both sides of the heart.

Ironically, Mira lacked a critical hole in her heart. Without this hole to relieve pressure on the left side of her heart, she would have been gravely ill at birth and potentially not survive to undergo further treatment.

She also has a genetic abnormality called Turner Syndrome, which places her at very high risk for traditional surgical approaches to HLHS. Norwood is a complex open heart surgery for any baby with HLHS, but especially so for Mira because she lacked the critical hole in her heart and was diagnosed with Turner.

The newborn had three strikes against her, and doctors began treating her in the womb.

How it was treated

First, using a needle inserted through the mother’s abdomen and into Mira’s heart, doctors used a balloon to create a much needed hole. The successful intervention on Dec. 2 allowed Mira to be stable at birth.

Next, physicians had to address HLHS, but the traditional series of surgeries were too risky for Mira. An emerging alternative to Norwood is a hybrid approach. In hybrid procedures, interventional cardiologists and cardiac surgeons work side-by-side to treat patients without using a heart bypass machine.

A cardiac team, led by Armstrong and Jennifer Hirsch, M.D., a U-M pediatric cardiac surgeon, performed two hybrid procedures on Mira Jan. 27, the day she was born, and another on Jan. 29.

Mira was taken from the delivery room to a cardiac catheterization laboratory. The team placed bands on the pulmonary arteries to direct more blood flow to the body, and placed a stent between the top chambers of the heart to further improve blood flow. Once she stabilized, the same team inserted additional stents to ensure blood flow to her body.

Mira will need more surgeries at 4 months old, and age 2, to further correct blood flow to her lungs.