At Boston Children's Hospital, we specialize in treating a wide range of congenital heart conditions in babies before and after they are born. Babies with congenital heart problems are treated by specialists called pediatric cardiologists. These physicians diagnose heart defects and help manage the health of children before and after surgical repair of the heart problem. Specialists who surgically correct heart problems in the operating room are called pediatric cardiovascular surgeons or pediatric cardiothoracic surgeons.
Treatment is based on the severity of your child's heart condition. Some mild heart defects don't require any treatment. Others can be treated with medications, interventional procedures or surgery. The most common defects we treat include:
- Aortic stenosis: This is a narrowing of the aortic valve of the heart that obstructs blood flow throughout the body. The severe form of aortic stenosis can lead to a serious defect called Hypoplastic left heart syndrome.
- Pulmonary atresia: This is a malformation of the pulmonary valve that obstructs the outflow of blood from the heart to the lungs. This can lead to underdevelopment of the right ventricle.
- Hypoplastic left heart syndrome with a restrictive atrial communication: This is an underdevelopment of the left ventricle of the heart that results in inadequate blood flow throughout the body.
Problem: Kids with congenital heart defects often suffer from heart failure, meaning their hearts can't pump adequately. And since heart muscle has very little growth capacity after birth—nowhere near enough to fix a severe cardiac injury—heart transplant is often the sole treatment option.
Innovative solution: Researchers in Boston Children's Cardiovascular Program have discovered a growth factor, called neuregulin1 (NRG1), that can reawaken the heart's regenerative capacities, and may be able to strengthen the heart after a heart attack and in children and adults with heart failure. NRG1, which is involved in the initial development of the heart and nervous system, spurred heart-muscle growth and recovery of cardiac function when injected systemically in rats; preparations are underway to test the growth factor in humans. Doctors now envision a time when patients will receive monthly infusions to build up their hearts.
Problem: Invasive open-heart surgery in infants can be risky
Innovative solution: The Medtronic Melody Transcatheter Pulmonary Valve is a prosthetic valve that was developed to treat patients with congenital heart disease affecting the function of the pulmonary valve. The valve is implanted through a catheter procedure, rather than a more invasive open-heart surgical procedure. This makes the demands on your child's recovery much easier and far less intensive.
The device has been approved for use in Europe and Canada for years. Once approved by the Food and Drug Administration, pending review of a five-center investigative study that included Boston Children's, the valve will be the first catheter-implanted valve approved in the United States.
Results of the study, published in October of 2009, include 29 patients who underwent successful surgery.
- Of 24 patients who had Class II or III heart failure (mild to moderate limitation of physical activity) before the procedure, 19 had improved by at least one functional class at six months, and no patient's function had declined
- No patient had more than mild pulmonary regurgitation
Based on results from the study, Medtronic is currently working on an improved model.
Longer term studies are needed to monitor the quality of the device. Like other prosthetic valves, the Melody Transcatheter Pulmonary Valve is likely to need replacement several times over the course of a patient's life due to wear and tear. However, since the Melody can be implanted through a catheter, there is minimal risk to the patient compared to valves that can only be implanted surgically.
Hunting down the genetic causes of congenital heart disease
While there is a lot of evidence that congenital heart disease can be caused by genetic mutations, many of the affected genes remain unknown. In the effort to discover more genetic causes, Boston Children's is joining with Brigham and Women's Hospital (BWH) as part of the Bench to Bassinet Program, a six-year, $100 million collaboration funded by the National Heart Lung and Blood Institute that aims to propel basic pediatric cardiac research toward clinical treatment.
Jane Newburger, MD, MPH, associate cardiologist-in-chief at Boston Children's, and Christine Seidman, MD, director of the Cardiovascular Genetics Center at BWH, will lead the effort. Clinical geneticists and basic scientists will collect DNA samples from pediatric heart patients and map the genetic program that directs heart development. Patients will undergo cardiac imaging to establish their disease phenotype while their samples undergo DNA sequencing and genomic analysis.
The data will be combined with data from the other Pediatric Cardiac Genomics Consortium (PCGC) institutions funded by the Bench to Bassinet Program, including Yale University, Mt. Sinai School of Medicine, Columbia University and Children's Hospital of Philadelphia. The partnership also allows the collaborators to share patient samples and technology.
“Competition inspires people to work quickly, but this particular area of research begs for collaboration,” says co-investigator Amy Roberts, MD, director of Boston Children's Cardiovascular Genetics Research Program who, under separate grants, is studying the genetics of hypoplastic left heart syndrome and Noonan syndrome.
Separately funded projects by William Pu, MD, of Boston Children's Cardiovascular Program, will use induced pluripotent stem cell technology to model congenital heart disease in the lab, and explore how alterations in microRNA expression and gene transcription factors may lead to heart disease.