Treating Congenital Heart Defects: Two Devices Offer an Alternative to Surgery

The Heart's Chambers

The heart has four chambers—the upper two are the right and left atria and the lower two are the right and left ventricles. The right and left sides of the heart are divided by an internal partition called the septum. A congenital cardiovascular defect lets blood flow between the heart's right and left chambers due to an unnatural opening in the septum.

The two most common types of this defect are:

• Atrial septal defect (ASD)–an opening exists between the heart's two upper chambers. About 4%-10% of the 35,000 babies born each year in the United States with cardiovascular defects have this type of defect.
• Ventricular septal defect (VSD)–an opening exists between the two lower chambers of the heart. About 14%-17% of the 35,000 babies born each year in the United States with cardiovascular defects have this type of defect.

Closing Ventricular Septal Defects

The CardioSEAL Septal Occlusion System, made by NMT Medical, was approved to close complex ventricular septal defects. CardioSEAL is made of two metal frameworks shaped like umbrellas—one for each side of the septum. A polyester fabric is attached to each umbrella.

Using spring coils in the framework, CardioSEAL can be collapsed into an artery or a vein for insertion into the heart. Once it is positioned with an umbrella on each side of the defect, the CardioSEAL is opened. The septal tissue grows into and around the umbrella, incorporating it into the septum.

Closing Atrial Septal Defects

The Amplatzer Septal Occluder, made by AGA Medical Corporation, was approved to close secundum atrial defects—those located in the mid-portion of the atrial septum. The Amplatzer is a self-expandable, double disc device filled with polyester fabric. The discs are linked by a short connecting waist that corresponds to the size of the septum's defect.

The Amplatzer is implanted through a small catheter that is inserted into a vein in the patient's groin. The doctor threads the device through some of the body's largest veins until it reaches the heart. Once the device is in place, the doctor releases it from the end of the catheter. The Amplatzer springs open and clamps the defect. The body's tissue eventually encases the device.

Talk With Your Doctor

Both devices have contraindications, warnings, and precautions. Several centers have reported migration of devices from their intended sites, a complication requiring urgent open surgery. Before deciding on any medical procedure, it is important to discuss all possible options with your doctor to determine what is best for your situation.

Make sure your doctor is aware of the latest literature on both of these devices. As a condition of approval, the FDA is requiring each company to closely study each product until 2007 to better assess the long-term safety and effectiveness of the devices. These procedures may not be easy or rapid for surgeons to learn, but barring unforeseen or frequent complications, they will likely offer new options for repairing a variety of congenital heart problems.