Atrial Septal Defects
According to the American Heart Association, about 40,000 babies are born every year with some type of heart defect. The most common type is an atrial septal defect (ASD), a hole in the wall (the septum) that separates the two upper chambers of the heart. The abnormal opening allows some of the oxygen-rich blood from the left side of the heart to leak back into the right side, where it's pumped back to the lungs.
Most patients with ASD have no symptoms and the condition may not be diagnosed until adulthood. But untreated, the condition can cause enlargement of the chambers on the right side of the heart, stretching and leaking of the valve between right upper and lower chambers (the tricuspid valve), pulmonary hypertension (increased blood pressure in the vessel leading to the lungs), heart rhythm abnormalities, or heart failure. Some patients may develop blood clots that can break loose, travel to the brain, and cause a stroke. Patients are also at risk for developing pulmonary vascular obstructive disease, in which the pulmonary arteries become thickened and blocked from the increased blood flow.
Fixing Atrial Septal Defects: The HELEX device In up to 20 percent of affected children, an atrial septal defect closes on its own within a year. If the hole needs to be repaired, doctors traditionally turn to open heart surgery. The treatment is very effective, but patients must be placed on a heart-lung machine and face recovery from a large chest incision.
Researchers are testing several devices which can close an atrial septal defect through catheterization, avoiding the need for open heart surgery. One of them is the HELEX system, a nickel-titanium (nitinol) wire covered with a microporous polytetrafluoroethylene patch. First, doctors make a tiny cut into a vein in the groin area. Using x-rays and special dye for guidance, a catheter is fed through the circulatory system, into the right atrium of the heart, and through the hole in the septum. One part of the HELEX is released to cover the hole from the left side of the heart. The rest of the device covers the hole from right side. After doctors confirm the position of the HELEX and closure of the hole, the device is completely released and the catheter is withdrawn. Patients are generally home from the hospital the next day and back to school the next. Over time, normal tissue grows around the HELEX, making the seal permanent.
Currently, the HELEX is an investigational device. Doctors are trying to see if the system is as safe and effective as open heart surgery for children with atrial septal defects. Although the HELEX comes in varying sizes, it's best for patients with small to moderate-sized defects. Children with larger holes may still need open heart surgery to repair their defect.