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Balloon Atrial Septostomy

Balloon Atrial Septostomy

If a fetus is determined to have hypoplastic left heart syndrome (HLHS) with an intact atrial septum, they may be a candidate for a balloon atrial septostomy. The fetal heart is accessed in utero via a specialized needle, which is directed across the atrial septum to create a communication to the left atrium.

A wire and small balloon are then guided into the left atrium, and the tiny hole is enlarged by inflation of the balloon. If the balloon dilation alone does not result in a sufficient atrial communication, then, a stent can be deployed as well.

HLHS circulation after birth without an atrial septal defect

Blue (deoxygenated) blood enters the right atrium from the rest of the body. This blue blood is then pumped primarily to the lungs to collect oxygen. The red (oxygenated) blood returns to the heart from the lungs into the left atrium. When the mitral valve is small and there is no atrial septal defect, the red blood has no way of getting out of the heart and delivering oxygen to the other organs.

Instead of red blood, blue blood is then pumped to the body via a residual fetal structure called the patent ductus arteriosus. This results in rapid deterioration of the newborn.

HLHS circulation after birth with an atrial septal defect

As above, red blood enters the left atrium from the lungs. When an atrial septal defect is present, the oxygenated blood can then escape the left atrium and mix with the other blood to increase the oxygen content of the blood. This mixed blood is pumped to the other organs via the patent ductus arteriosus and has adequate oxygen content for the baby to be stable until surgery several days later.

After the procedure

Babies receiving this unique fetal procedure at Texas Children's Fetal Center will continue treatment immediately after delivery at Texas Children's Heart Center.

Following each procedure, physicians monitor the mother and baby through multiple fetal ultrasounds and echocardiograms so that the mother may carry the baby as close to full term as possible, giving the lungs, brain and other vital organs a chance to mature prior to birth. This allows the child to become more stable before undergoing his or her first heart surgery.

Texas Children’s Fetal Center is the first center in the southwestern United States to successfully develop a fetal cardiac intervention program. Our multi-disciplinary team of experts in Maternal Fetal Medicine, Fetal Cardiology Pediatric Cardiac Intervention and Maternal/Fetal Anesthesia has performed in utero fetal cardiac interventions that addressed problems related to severe fetal left heart obstruction in fetuses with critical aortic valve stenosis or HLHS.