The heart is divided into four chambers. The upper chambers are the atria and the lower chambers are the ventricles. The right side of the heart—right atrium and right ventricle—pump blood to the lungs to pick up oxygen and the left side of the heart takes this oxygen-rich blood and sends it throughout the body. The system works very well when the right and left sides of the heart are separated by heart muscle in the middle, known as a septum. When there is a hole in the wall between the two atria, it is known as an atrial septal defect. By extension, the surgery to repair this congenital heart abnormality is called atrial septal defect closure.
An atrial septal defect can go unnoticed for some time or it can cause life-threatening problems. It may sound like a soft heart murmur or be detected incidentally on an echocardiogram. No matter how it is diagnosed, if an atrial septal defect or ASD causes serious symptoms, it needs to be closed.
The traditional way to perform an ASD closure surgery requires “open heart” surgery which means the breastbone is cut lengthwise and the chest is opened. The blood flow is diverted through a heart-lung bypass machine or pump and the heart is drained of blood. Then either the existing heart muscle is sewn closed, a graft of tissue is placed, or a wire mesh is implanted to block the hole in the atrial septum. While the procedure has been highly successful, this approach certainly qualifies as a major surgery and the ASD closure recovery process can be quite long and slow.
A newer approach to ASD closure surgery is through the use of a percutaneous ASD closure. The percutaneous approach is similar to what takes place during an angiogram of the right side of the heart. An incision is made in the femoral vein in the upper leg and a catheter is placed in the vein. The catheter is moved up the vein to the right side of the heart. A small amount of dye that shows up on X-ray (fluoroscopy) is administered to verify location. Then a metal, mesh plug is expanded to fill in the atrial septal defect. Once the device is in place, more dye is administered to verify placement and the catheter is removed. After a few weeks, the wire material is covered by new heart cells. In fact, the ASD closure device acts as scaffolding for new heart septum to grow.
The first device of this kind approved for the repair of atrial septal defects is the Amplatzer ASD closure device. It is manufactured and sold by the AGA Medical Corporation, the company who pioneered this technique and others related to it.
The beauty of the Amplatzer ASD closure device (and other percutaneous ASD closure devices as they become available) is that it allows the patient to avoid open heart surgery altogether. Instead of a foot long incision in the chest, there is an inch long incision in the leg. The time spent in the hospital is markedly less with the percutaneous ASD closure approach.
There are some considerations and limitations of the Amplatzer ASD closure device. It is made of a nickel alloy so patients that are allergic to nickel would not be candidates for this procedure. Also, it is not always possible to use the Amplatzer ASD closure device to fill in larger atrial septal defects. This can usually be determined before device deployment/surgery. Some of the more serious complications of percutaneous ASD closure are infection (including endocarditis), stroke, and damage to the blood vessels. These are rare and, when you consider the complication rate associated with any open heart surgery, percutaneous ASD closure may be a reasonable approach in select patients.