Fixing heart defects in children

MIAMI, Fla. – More than 35,000 babies are born with a heart defect.  For many, this means a lifetime of surgery and medicine. Now, for the first time, doctors are using stem cells to save their smallest patients and hopefully keep them off medication and out of the OR.

Analiah runs the Duarte home, literally!

"I try to walk with her and she's like leave me alone," Johanna Duarte, Analiah's mom said.

Analiah was born with one of the most lethal and rare congenital heart defects. It's called Ebstein's anomaly one of Analiah's heart valves failed to form.  

"They're left with this horrible non-functional valve that allows blood to slosh back and forth inside their heart," said Redmond Paul Burke, MD, Chief in the Division of Pediatric Cardiovascular Surgery at Miami Children's Hospital.

 Burke says it causes hearts to grow four, five, six times larger than normal.

"Analiah was born with a heart that filled her entire chest," Burke said.

Previously, surgeons would repair, replace, or close her valve, but that surgery would need to be done over and over as she grows.

"The holy grail for heart valve repair and replacement is a valve that will grow with the child," said Burke.

Doctors created the valve out of extracellular matrix, a substance extracted from a pig's bladder. The implant acts like a fishnet. It captures stem cells flowing in Analiah's blood stream. The cells attach to the impact, grow around it, and create a new heart valve.

"We could see, for the first time in her life, the valve that we had created opening and closing," Burke explained.

A year later, Analiah's valve is working. As a result, her heart is now a third of the original size.

Burke says Analiah's new valve should grow with her throughout her life; so she would not need a transplant, drugs, or more surgery. He also believes this could be used in adults to replace heart valves.

Additional Information:

Congenital heart defects are abnormalities in the heart's structure that are present at birth.  About eight out of every 1,000 newborns have congenital heart defects.  They happen because of an incomplete or abnormal development of the baby's heart during the early weeks of pregnancy.  Some have been associated with genetic disorders, like Down syndrome, but the cause of most congenital heart defects are unknown.  (Source: www.kidshealth.org)

SYMPTOMS: Congenital heart defects compromise the heart's ability to pump blood and to deliver oxygen to the tissues of the body. So, they often have telltale signs like:

  • an increased rate of breathing or difficulty breathing
  • a bluish color to the tongue, lips, and/or nail beds
  • poor appetite or difficulty feeding
  • abnormal heart murmur
  • diminished strength of the baby's pulse
  • sweating, especially during feedings
  • failure to gain weight (Source: www.kidshealth.org)

EBSTEIN'S ANOMALY: Analiah Duarte had one of the most rare and lethal heart defects, called Ebstein's anomaly.  It affects one in 200,000 U.S. births.  In Ebstein's anomaly, the tricuspid valve, the valve between the chambers on the right side of the heart, doesn't work properly.  Blood leaks back through the valve, making the heart work less efficiently.  It can also lead to heart failure or enlargement of the heart.  This heart defect occurs early in the development of a baby's heart.  It is uncertain what risk factors cause the defect.  Environmental and genetic factors are both thought to play a role.  A mother's exposures to certain medications, like benzodiazepines or lithium, have been associated with Ebstein's anomaly in children.  (Source: www.mayoclinic.com)

NEW TECHNOLOGY:  Medical-biomaterial-company CorMatrix Cardiovascular, based in Georgia, had developed an extracellular matrix material, a collagen framework that cells could attach to and hold the organs together.  It has the structure, shape, and signaling properties to attract stem cells.  "If you put this sub-mucosal tissue anywhere in the body, it functions like a fisherman's net.  It captures stem cells flowing through the bloodstream right where you want them. It's like having the framework of a house that can actually recruit all the bricks and wood need to create a perfect house," Redmond Paul Burke, MD, Chief, Division of Pediatric Cardiovascular Surgery at Miami Children's Hospital, was quoted as saying.  The stem cells that are captured morph into the tissue needed for the malfunctioning organ to work properly.  Previously, doctors would use the material to promote natural growth of human organs.  Dr. Burke was the first to use it to fashion a baby's heart valve.  Dr. Burke made a valve from the sub-mucosal lining of a pig's intestine.  He sewed it in the place where the tricuspid valve would have been.  The valve Dr. Burke made was anchored at two points: at the opening and on the other side that allowed the blood to flow into the right ventricle.  When the right ventricle contracts, the slit closes and blood is pushed out the pulmonary valve.  Doctors believe that the stem cells the matrix captures will help Analiah rebuild her own valve.  They say it would eliminate the need for follow-up surgeries usually needed for children with an implanted valve.  As the patient's heart grows, surgeons will need to replace the implanted valves with bigger ones.  "Time will tell if her own valve has become her own living human valve," Dr. Burke was quoted as saying.
(Source: Miami Herald)