Using a Printed 3-D Model as a Guide, Children’s Hospital Los Angeles Cardiologist Creates a Modified Stent to Repair an 18-month-old’s Pulmonary Artery and Gives a Family Hope

National Congenital Heart Defects Awareness Week is February 7-14,
2017

LOS ANGELES–(BUSINESS WIRE)–When Children’s Hospital Los Angeles cardiologists found evidence that a
portion of Nate Yamane’s pulmonary artery they had repaired once before
was again narrowing, Pediatric Interventional Cardiologist Frank Ing,
MD, decided they needed to insert a stent to keep the right artery open.


But due to the size of the narrowing, about 9 millimeters, doctors
needed to customize the stent to fit into the smaller space and they
wanted to perfect their measurements before the actual procedure. How?
Using CT scans of Nate’s heart, they created a 3-D printed model of the
obstructed region. Dr. Ing was then able to fashion a smaller stent to
fit precisely into the narrowed artery in the model.

“I have to say, the 3-D model was very helpful because it gave me
confidence that [the size of the stent] was going to work,” says Ing.

Nate has had a tough 18 months. Born in June 2015 with tetralogy of
Fallot (TOF) with pulmonary atresia, the 7.1-pound infant had trouble
breathing shortly after birth. The cause: a genetic abnormality
resulting in heart defects that obstructed his pulmonary artery,
preventing blood pumped by the heart from flowing into the lungs.

He was rushed to Children’s Hospital Los Angeles from a South Bay
hospital in critical condition. Pulmonary atresia – a more severe
version of TOF – occurs when the pulmonary artery fails to form properly
in utero, prompting the human body to grow collateral arteries that
redirect blood around the obstruction and to the lungs (a typical
development with these types of blockages). About one in 10,000 children
are born with this congenital heart defect.

“Imagine blood flowing in the artery like cars on the freeway, and it’s
blocked. Cars exit and find an alternate route to its destination; blood
does the same, and in this case finds its way through collateral vessels
to the lungs,” explains Dr. Ing, the chief of the Division of Cardiology
and co-director of the Heart Institute at Children’s Hospital Los
Angeles.

But after birth, those vessels need to be rebuilt quickly or the heart
will fail. Using a surgical technique called unifocalization, surgeons
can repair the vessels by sewing them together. “We use whatever the
body gives us,” explains Dr. Ing, a professor of Clinical Pediatrics and
Medicine at the Keck School of Medicine of the University of Southern
California.

A month into his young life, Nate had undergone two open heart surgeries
and a catheterization procedure, but doctors were not done. In December
2015, Nate’s pulmonary arteries were found to be narrowed in both the
right and the left branch. At the time, a team led by Ing was able to
use a balloon to open the right side. However, to keep the left section
open they had to insert a stent, specially modified using a technique
developed at CHLA, to fit the narrowed portion of the child’s left
pulmonary artery (about 15mm). Stents do not normally come that small,
but by carefully cutting their smallest existing stent and folding it
back upon itself, Dr. Ing tailored a functional custom stent that worked
perfectly and did not jut out needlessly into other areas. Almost
immediately, Nate saw marked improvement in blood flow, including a
healthy drop in blood pressure. Still, in the coming months, he gained
little weight and had to grow bigger and stronger before considering
another procedure. “We did physical therapy and tried to fatten him up,”
says Nate’s mother, Courtney.

On Jan. 19, 2017, Dr. Ing inserted the second, even smaller stent into
Nate’s right pulmonary artery in CHLA’s catheterization lab before a
captivated international audience of cardiologists, watching on a live
video feed at the Pediatric and Adult Interventional Cardiac Symposium
in Miami. Using the stent that was modified in advance to the same
specifications in the model, Ing and his team were able to open up
Nate’s right pulmonary artery, with successful results; Nate’s oxygen
levels improved overnight.

In the months and years ahead, Nate will need additional surgeries, but
his weight is up to 21.5 lbs., and he’s eating better and getting
stronger. “He’s rolling around with energy and even took his first baby
steps,” says Courtney, who also has a four-year-old at home. “There’s a
big difference and a lot of improvement. We’re going in the right
direction.”

About Children’s Hospital Los Angeles

Children’s Hospital Los Angeles has been named the best children’s
hospital in California and among the top 10 in the nation for clinical
excellence with its selection to the prestigious U.S. News & World
Report Honor Roll. Children’s Hospital is home to The Saban Research
Institute, one of the largest and most productive pediatric research
facilities in the United States. Children’s Hospital is also one of
America’s premier teaching hospitals through its affiliation with the
Keck School of Medicine of the University of Southern California since
1932.

For more information, visit CHLA.org.
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Contacts

Children’s Hospital Los Angeles
Lorenzo Benet
323-361-4823
lbenet@chla.usc.edu