Balloon Dilation of Aortic Valve


Balloon dilation of the aortic valve is a fetal procedure used to widen a severely narrowed aortic valve opening, a condition known as aortic stenosis, to improve blood flow through the left side of the fetal heart.

The procedure is performed if the fetus has aortic stenosis that is thought will progress to hypoplastic left heart syndrome (HLHS), a complex congenital heart defect that occurs when the left side of the heart does not form properly. Without intervention, the left ventricle in fetuses with aortic stenosis often stops growing, leaving it too small to use at birth.

For some fetuses, fetal intervention to dilate or widen the aortic valve may increase blood flow across the valve and allow the left side of the heart to continue growing so it is better developed at birth.

Balloon dilation of the aortic valve is also referred to as fetal aortic valvuloplasty.

Improving Outcomes Through Early Intervention

In-utero balloon aortic valvuloplasty, if successful, increases the potential for the child to have a biventricular repair after birth, a procedure to achieve two functioning (pumping) ventricles.

If no intervention is performed, fetal aortic stenosis will often progress to HLHS, a serious condition requiring immediate intervention at birth. Outcomes for children born with HLHS are uncertain and vary greatly by patient. Most children require three heart surgeries before the age of 6 to alter the cardiac “plumbing,” and most are expected to need a heart transplant later in life.

With fetal aortic valvuloplasty, the goal is to allow the left ventricle to stay sufficient size. Even with a successful valvuloplasty, most children will require either cardiac surgery or cardiac catheterization after birth. The hope is that children with a biventricular repair will have better long-term outcomes than those whose fetal condition progressed to HLHS and have only a usable right ventricle.

Texas Children’s Fetal Center is one of the few centers in the world offering this procedure. In collaboration with the Texas Children’s Heart Center, our Fetal Center has successfully performed fetal balloon dilation of aortic valve since 2012.

Is my baby a candidate for balloon dilation of the aortic valve?

Balloon dilation of the aortic valve may be recommended if your baby has been diagnosed with aortic stenosis that is suspected to evolve to HLHS.

Each case and each heart defect is unique, requiring close evaluation and individualized planning by a team of specialists experienced in the treatment of severe congenital heart conditions.

At Texas Children’s Fetal Center, our large multidisciplinary team includes some of the nation’s top maternal-fetal medicine specialists, congenital heart surgeons, interventional cardiologists, fetal and pediatric cardiologists, fetal imaging experts, neonatologists, pulmonologists, and maternal and fetal anesthesiologists, among others, for the treatment of fetal heart defects.

This team of experts will carefully study your case and make treatment recommendations to help your family make the most informed decisions.

About the Procedure

In most cases, balloon dilation of the aortic valve is recommended between 20 to 29 weeks of pregnancy. During that period, mother and baby will be closely monitored to determine optimal timing for the procedure.

The day of the procedure, the mother will be admitted to the hospital. The procedure is typically performed with epidural anesthesia, not general anesthesia, for the mother. The epidural will be placed and an ultrasound will be performed to determine the position of the fetus.

Once the fetus is in the desired position, medication will be given to the fetus to prevent pain during the procedure and limit movement, enabling the procedure to be performed as safely as possible.

During the ultrasound-guided procedure, the surgeon will insert a special needle through the mother’s abdomen and uterus, and into the baby’s heart. Once in position, a wire with an attached balloon will be threaded through the needle, and across the narrowed aortic valve. The tiny balloon is then gently inflated, enlarging the opening of the aortic valve and increasing blood flow into the left ventricle. The balloon is then deflated and the balloon, wire, and needle are removed.

Balloon Dilation

During the ultrasound-guided procedure, the surgeon will insert a special needle through the mother’s abdomen and uterus





Before Balloon Dilation

Before balloon dilation of the aortic valve

After Balloon Dilation

After balloon dilation of the aortic valve



As with any surgical procedure, balloon dilation of the aortic valve involves risks, including:

  • Preterm labor
  • Loss of pregnancy
  • Damage to the fetus
  • Fluid around fetal heart
  • Slowing of the fetal heart rate

After the Procedure

The typical hospital stay following a fetal balloon dilation of the aortic valve is 48 hours. During this time mother and unborn baby will be closely monitored. Upon discharge, your pregnancy will be carefully followed with regular checkups, including fetal ultrasounds  and fetal echocardiograms to evaluate the baby’s development and heart condition.

The goal is for the mother to carry the baby as close to full term as possible, giving the fetal lungs, brain and other vital organs a chance to mature as much as possible before delivery. This allows the child to become more stable before undergoing heart surgery after birth.


For the best possible outcomes, delivery should take place at a center with the highest quality congenital heart program, ensuring the expertise and resources required at birth to treat this rare, complex congenital heart defect.

Our Fetal Center specialists work closely with Texas Children’s Heart Center every step of the way, seamlessly transitioning your baby’s care at delivery to this national leader in pediatric cardiology and heart surgery.

Following delivery at Texas Children’s Pavilion for Women, newborns are transferred to Texas Children’s level IV neonatal intensive care unit (NICU), the highest level of care available for premature and critically-ill newborns, or Texas Children’s specialized cardiac intensive care unit

Research and Clinical Trials

Texas Children’s, together with its partner institution Baylor College of Medicine, constantly strives to seek new and better treatments for babies with congenital heart issues of all types.

  • Chronic Hyperoxygenation for Borderline Left Heart – For fetuses with borderline left heart structures, where multiple left-sided heart structures are smaller than they should be, Texas Children’s Fetal Center was the first in the country to offer a research protocol in which mothers receive daily oxygen therapy throughout their third trimester. This study is ongoing.

    By delivering extra oxygen to the mother through a face mask or cannula, we hope to increase the amount of oxygen in her blood, the amount of oxygen going to the placenta and fetus, and ultimately the amount of oxygen flowing into the fetal lungs and the left side of the baby’s heart. Improving oxygen flow to the left side of the heart should improve growth as well. We are also studying the effects of extra oxygen for the fetal brain.
  • International Fetal Cardiac Intervention Registry (IFCIR) – Texas Children’s Fetal Center is one of the few specialized centers in the world performing these fetal cardiology procedures. As a member of the International Fetal Cardiac Intervention Registry, we have joined forces with other centers to evaluate and improve these still rare, complex and innovative fetal intervention procedures, improving the care and outcome for mothers and babies in pregnancies complicated by congenital heart disease in the fetus.

Learn more about our fetal cardiology research

Volumes and Outcomes


Additional Resources

Prenatal Classes at Texas Children’s Pavilion for Women

Why Texas Children’s Fetal Center?

Texas Children’s Fetal Center is one of the oldest and most experienced programs in the nation. We have a history of leading the development and implementation of innovative fetal therapies and procedures such as balloon dilation of the aortic valve, offering families new options and new hope for the treatment of congenital heart defects and other fetal abnormalities.

Here, you and your baby will receive expert maternal, fetal and pediatric care all in one state-of-the-art location. We offer extensive experience performing in-utero fetal cardiac interventions with some of the most successful outcomes in the nation.

Our Fetal Cardiology Program brings together a multidisciplinary team of experts from Texas Children’s Fetal Center and Texas Children’s Heart Center, ranked #1 in the nation for pediatric cardiology and heart surgery by U.S. News & World Report.

Texas Children’s Fetal Cardiology Publications - HLHS and Related Disorders

Edwards LA, Lara DA, Sanz Cortes M, Hunter JV, Andreas S, Nguyen MJ, Schoppe LJ, Zhang J, Smith EM, Maskatia SA, Sexson-Tejtel SK, Lopez KN, Lawrence EJ, Wang Y, Challman M, Ayres NA, Altman CA, Aagaard K, Becker JA, Morris SA. Chronic Maternal Hyperoxygenation and Effect on Cerebral and Placental Vasoregulation and Neurodevelopment in Fetuses with Left Heart Hypoplasia. Fetal Diagn Ther. 2018

Sep 17:1-13. doi: 10.1159/000489123. [Epub ahead of print] PubMed PMID: 30223262.

Dailey-Schwartz AL, Tadros HJ, Azamian MS, Lalani SR, Morris SA, Allen HD, Kim JJ, Landstrom AP. Copy Number Variants of Undetermined Significance Are Not Associated with Worse Clinical Outcomes in Hypoplastic Left Heart Syndrome. J Pediatr. 2018 Nov;202:206-211.e2. doi: 10.1016/j.jpeds.2018.07.022. Epub 2018 Aug 29. PubMed PMID: 30172441; PubMed Central PMCID: PMC6203622.

Buffie AW, Belfort MA, Shamshirsaz AA, Justino H, Qureshi AM, Ayres NA, Morris SA, Espinoza J. Two- and Four-dimensional Ultrasonography of an Interatrial Stent in a Fetus With Hypoplastic Left Heart  Syndrome. J Ultrasound Med. 2019 Feb;38(2):549-551. doi: 10.1002/jum.14718. Epub 2018 Jul 29.  PubMed PMID: 30058144.

Jantzen DW, Moon-Grady AJ, Morris SA, Armstrong AK, Berg C, Dangel J, Fifer CG, Frommelt M, Gembruch U, Herberg U, Jaeggi E, Kontopoulos EV, Marshall AC, Miller O, Oberhoffer R, Oepkes D, Pedra CA, Pedra SR, Peralta F, Quintero RA, Ryan G, Gelehrter SK. Hypoplastic Left Heart Syndrome With Intact or Restrictive Atrial Septum: A Report From the International Fetal Cardiac Intervention Registry. Circulation. 2017 Oct 3;136(14):1346-1349. doi: 10.1161/CIRCULATIONAHA.116.025873. Epub 2017 Sep 1. PubMed PMID: 28864444.

Hanchard NA, Umana LA, D'Alessandro L, Azamian M, Poopola M, Morris SA, Fernbach S, Lalani SR, Towbin JA, Zender GA, Fitzgerald-Butt S, Garg V, Bowman J, Zapata G, Hernandez P, Arrington CB, Furthner D, Prakash SK, Bowles NE, McBride KL, Belmont JW. Assessment of large copy number variants in patients with apparently isolated congenital left-sided cardiac lesions reveals clinically relevant genomic events. Am J Med Genet A. 2017 Aug;173(8):2176-2188. doi: 10.1002/ajmg.a.38309. Epub 2017 Jun 27. PubMed PMID: 28653806; PubMed Central PMCID: PMC5560080.

Hanchard NA, Swaminathan S, Bucasas K, Furthner D, Fernbach S, Azamian MS, Wang X, Lewin M, Towbin JA, D'Alessandro LC, Morris SA, Dreyer W, Denfield S, Ayres NA, Franklin WJ, Justino H, Lantin-Hermoso MR, Ocampo EC, Santos AB, Parekh D, Moodie D, Jeewa A, Lawrence E, Allen HD, Penny DJ, Fraser CD, Lupski JR, Popoola M, Wadhwa L, Brook JD, Bu'Lock FA, Bhattacharya S, Lalani SR, Zender GA,

Fitzgerald-Butt SM, Bowman J, Corsmeier D, White P, Lecerf K, Zapata G, Hernandez P, Goodship JA, Garg V, Keavney BD, Leal SM, Cordell HJ, Belmont JW, McBride KL.  A genome-wide association study of congenital cardiovascular left-sided lesions shows association with a locus on chromosome 20. Hum Mol Genet. 2016 Jun 1;25(11):2331-2341. Epub 2016 Mar 9. PubMed PMID: 26965164; PubMed Central PMCID: PMC5081047.

Mery CM, Nieto RM, De León LE, Morris SA, Zhang W, Colquitt JL, Adachi I, Kane LC, Heinle JS, McKenzie ED, Fraser CD Jr. The Role of Echocardiography and Intracardiac Exploration in the Evaluation of Candidacy for Biventricular Repair  in Patients With Borderline Left Heart Structures. Ann Thorac Surg. 2017 Mar;103(3):853-861. doi: 10.1016/j.athoracsur.2016.07.043. Epub 2016 Oct 4. PubMed PMID: 27717424.

Lara DA, Morris SA, Maskatia SA, Challman M, Nguyen M, Feagin DK, Schoppe L, Zhang J, Bhatt A, Sexson-Tejtel SK, Lopez KN, Lawrence EJ, Andreas S, Wang Y, Belfort MA, Ruano R, Ayres NA, Altman CA, Aagaard KM, Becker J. Pilot study of chronic maternal hyperoxygenation and effect on aortic and mitral valve annular dimensions in fetuses with left heart hypoplasia. Ultrasound Obstet Gynecol. 2016 Sep;48(3):365-72. doi: 10.1002/uog.15846. PubMed PMID: 26700848.

Lara DA, Ethen MK, Canfield MA, Nembhard WN, Morris SA. A population-based analysis of mortality in patients with Turner syndrome and hypoplastic left heart syndrome using the Texas Birth Defects Registry. Congenit Heart Dis. 2017 Jan;12(1):105-112. doi: 10.1111/chd.12413. Epub 2016 Sep 29. PubMed PMID: 27685952.

Moffett BS, Garrison JM, Hang A, Morris SA, Tsang R, Dinh K, Griffiths P, Bronicki R, Checchia PA. Prostaglandin Availability and Association with Outcomes for Infants with Congenital Heart Disease. Pediatr Cardiol. 2016 Feb;37(2):338-44. doi: 10.1007/s00246-015-1282-6. Epub 2015 Oct 24. PubMed PMID: 26499357.

Moon-Grady AJ, Morris SA, Belfort M, Chmait R, Dangel J, Devlieger R, Emery S, Frommelt M, Galindo A, Gelehrter S, Gembruch U, Grinenco S, Habli M, Herberg U, Jaeggi E, Kilby M, Kontopoulos E, Marantz P, Miller O, Otaño L, Pedra C, Pedra S, Pruetz J, Quintero R, Ryan G, Sharland G, Simpson J, Vlastos E, Tworetzky W, Wilkins-Haug L, Oepkes D; International Fetal Cardiac Intervention Registry. International Fetal Cardiac Intervention Registry: A Worldwide Collaborative Description and Preliminary Outcomes. J Am Coll Cardiol. 2015 Jul 28;66(4):388-99. doi: 10.1016/j.jacc.2015.05.037. PubMed PMID: 26205597.

Morris SA, Ethen MK, Penny DJ, Canfield MA, Minard CG, Fixler DE, Nembhard WN. Prenatal diagnosis, birth location, surgical center, and neonatal mortality in infants with hypoplastic left heart syndrome. Circulation. 2014 Jan 21;129(3):285-92. doi: 10.1161/CIRCULATIONAHA.113.003711. Epub 2013 Oct 17. PubMed PMID: 24135071.

For more information or to schedule an appointment,

call Texas Children’s Fetal Center at 832-822-2229 or 1-877-FetalRx (338-2579) toll-free.

Our phones are answered 24/7. Immediate appointments are often available.