Cardiologist Uses New Method to Close Abnormal Blood Vessels

It eliminates need for surgery, is being tested at only two sites in the state

April 09, 2001

A cardiologist at Children's Hospital at Strong last week used a new method to close abnormal blood vessels, one that doesn't involve surgery, leave a scar, or require an extended hospital stay or recovery time. The procedure was performed Thursday on 9-month-old Scott Wakefield of Buffalo, who was discharged the following day.

With the exception of Columbia-Presbyterian Medical Center in New York City, Children's Hospital at Strong is the only site in New York, Ohio, and Pennsylvania that has this new device, called an Amplatzer Duct Occluder

Daniel Miga, M.D., director of pediatric interventional cardiology at Children's Hospital at Strong, works in the catheterization lab, diagnosing and treating children who have heart problems. Cardiac catheterization involves advancing a catheter into the heart through blood vessels to obtain blood samples, take detailed pictures, and detect and correct congenital abnormalities of the heart.

"In the past, catheterization was used mainly as a diagnostic tool," Miga says. 'In recent years, we've found additional uses for the technology, and we use it regularly to treat congenital heart defects. We recently started using a new method to close abnormal blood vessels, and the technique is making a significant difference for patients."

Surgery no longer mandatory

Children's Hospital at Strong is one of 25 U.S. sites participating in a trial study of the Amplatzer Duct Occluder. The device provides an alternative to surgery when closing a hole in the Patent Ductus Arteriosus (PDA), a blood vessel that is one of the most common types of congenital heart defects. About 60 in every 100,000 babies are born with this condition.

The Amplatzer Duct Occluder is self-expandable and made from wire mesh. So small that its size is measured in millimeters, the device is used to close potentially life-threatening blood vessels.

"This is a vastly superior alternative to heart surgery, which was previously the only way to close these vessels," Miga says. "It is safe, effective, and can eliminate the need for surgery and a large incision in the side of the chest. It's a great device, one suitable for infants or adults."

How the vessel forms

Blood usually circulates throughout the body in an endless "figure-eight." One loop carries blood to the lungs to replenish the oxygen, and the other loop carries the oxygen-rich blood to the body. Before birth, however, the system works differently.

While in the womb, a developing baby receives oxygen from its mother's lungs. Because it is not breathing, it doesn't need as much blood flowing through its own lungs. So the blood from this loop can be used more efficiently, some of it takes a shortcut. Instead of going to the lungs, it goes to the rest of the body. These shortcuts normally close at birth or shortly thereafter. One of these shortcuts is called the ductus arteriosus, a small blood vessel connecting the pulmonary artery and aorta.

After birth, a baby's blood pressure increases in the aorta and on the left side of the heart. If the shortcut fails to close, blood flows through it in the opposite direction, from left to right. This condition is called Patent Ductus Arteriosus (PDA). Patent is a medical term that means open.

PDA can cause fatigue, difficult or rapid breathing, failure to grow normally, or chronic respiratory infections. Large openings can lead to heart failure and death.

How the device works

To implant the Amplatzer Duct Occluder, a child is sedated and given a local anesthetic at the spot where a tube will be inserted in a vein in the groin. The next step is to insert a small tube called a catheter into the child's groin, and then navigate it through some of the body's largest veins until it reaches the heart. After some testing, a catheter is used to insert the device, which springs open inside the aorta, just on the other side of the defect. In essence, it builds a new wall where the opening was.

The device is made of specially heat-treated nickel-titanium wires, and has super elastic properties. It can be compressed into a tiny tube for delivery. When it is releases from the end of the catheterization tube, it springs open, returning to its original shape.

As the device expands outward, it clamps the defect. Even for the healthiest patients, Miga says, open-heart surgery means spending several days in the hospital, enduring a significant amount of pain, and a recovery period that lasts several months.

Full-service in Rochester

Securing permission to use the Amplatzer Duct Occluder is one of the many ways Children's Hospital at Strong is becoming a leader in pediatric cardiology. In addition to hiring Miga last year, the department plans on adding several additional staff members this year.

"We've developed a strong, integrated program to care for children who have heart problems, and Dr. Miga's skills and experience complement the team we have here," says Steven Lipshultz, M.D., chief of pediatric cardiology at Children's Hospital at Strong. "It used to be that families had to drive to Cleveland or Boston for this type of service. Now, they can receive the highest quality of care right at home."

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