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Minimally invasive procedure fixes heart defect that allows blood clots to reach the brain

30.01.2003

When 29-year-old Eric Lange suddenly experienced several hours of mental confusion last July, physicians at Cedars-Sinai Medical Center naturally ordered brain scans and carotid artery studies in their first search for a cause.

With the initial exams turning out OK, Eric’s neurologist pursued other clues and ended up finding a heart defect called a patent foramen ovale, or PFO. A blood clot was believed to have slipped through the defect and out of the normal route of circulation that would have filtered it in the lungs. Instead, the clot traveled to Eric’s brain and temporarily blocked the flow of blood, causing a transient ischemic attack, or TIA, which is similar to a stroke but it does not cause permanent brain damage.

Saibal Kar, M.D., director of Interventional Cardiology Research in the Division of Cardiology, was able to repair the defect using a minimally invasive non-surgical approach to insert an innovative device, called CardioSEAL®, to close the hole, saving Eric the physical stress and months of recovery of open-heart surgery.

Eric said he had no idea that a problem existed. “I just woke up one morning, I went to leave my apartment and I couldn’t get the door open,” he recalled. “I couldn’t understand why. I asked my girlfriend to come help. She undid the deadbolt. I’m like, ‘I should have known that.’ I went outside and I couldn’t remember where I parked my car. I suddenly started thinking about other things and I couldn’t remember my phone number or anything. That ’s when I knew something was wrong.”

Eric’s thought processes remained jumbled for several hours after he arrived at the emergency department at Cedars-Sinai. “I later learned there that I couldn’t read. I could recognize words but I couldn’t get them to come out of my mouth. That lasted about five hours, all said and done, in the emergency room.”

Because initial tests provided no explanation for Eric’s episode, he was admitted to the hospital for a series of diagnostic procedures. Several days later, a special test called a bubble contrast echocardiogram detected a hole connecting the two upper chambers of the heart.

Normally, oxygen-depleted blood enters the heart’s right upper chamber (right atrium) and goes to the right lower chamber (right ventricle), where it is pumped out through the pulmonary arteries to the lungs for filtration and oxygenation. From the lungs, blood enters the left upper chamber (left atrium) and goes to the left lower chamber (left ventricle) where it is pumped out through the aorta to the arteries that feed the body.

The possibility of PFO arises because heart circulation is different before birth. The oxygen needs of the fetus are supplied by the circulation from the mother. Therefore, the fetus does not breathe on its own and there is no need for blood to circulate from the heart through the lungs. Instead, most of the blood flows through a hole (the foramen ovale) that exists between the two upper chambers of the heart, bypassing the right ventricle and the lungs.

When the newborn takes its first breath, pressure inside the vessels and the heart force a flap to close over the hole, rerouting the blood through the right ventricle and the lungs. This flap does not always close or seal tight enough to prevent some blood from passing between the upper chambers, at least occasionally. In most cases, this condition remains undetected and causes only minimal consequences, if any. PFOs often remain unnoticed even until late adulthood.

Dr. Kar said that in the past if an asymptomatic PFO happened by chance to be discovered, most surgeons chose to leave it untreated, especially because until recently open-heart surgery was required to patch the hole. The large incision, long recovery time and risk that go with major surgery usually outweighed the potential benefit unless the opening was especially large or the patient was vulnerable. Scuba divers, for example, may have a greater chance of experiencing a problem because bubbles of nitrogen that form in the blood during dives may pass through an untreated PFO.

The new technique enables physicians to reach the heart by inserting a catheter through a vein in the groin. The approach is similar to that used during routine cardiac catheterization. In the case of PFO closure, the catheter serves as a conduit for the delivery of the CardioSEAL®, a double umbrella device made of polyester fabric mounted on metallic framework.

Eric’s procedure was performed in a cardiac cath lab. Using X-ray (angiography) and ultrasound imaging, Dr. Kar threaded the catheter from the groin through a vein into the heart. Because the slender ultrasound imaging catheter was also inserted through a vein to the heart, there was no need for an ultrasound catheter to be placed down the esophagus, a procedure that would have required general anesthesia.

Dr. Kar then attached the closure device to a thin cable and slid it through the catheter to the site of the defect. When it was properly positioned in the center of the hole and released, the device opened and locked in place on both sides of the defect. Heart wall tissue would grow around the device within a few months, completely and permanently closing the hole.

The procedure was accomplished in less than an hour with only mild sedation and a local anesthetic. Watching the angiogram during the procedure, Eric was able to see the closure device being deployed “like two umbrellas that spring together,” he said. If he had not already been hospitalized for the diagnostic procedures, the treatment most likely would have been performed on an outpatient basis. Instead, he was discharged the following day.

“I was out to dinner with my parents the night I left,” said Eric. “It really is incredible.”

While a PFO is thought to be present in up to 12 percent of the normal population, as many as 40 percent of young patients like Eric who have a stroke caused by an unknown source may have a PFO. This suggests that the mechanism of stroke in these patients is the escape, through the PFO, of a “paradoxical embolism” – a clot that forms in the veins but makes its way into the arterial circulation. Experts believe that stroke patients with a relatively large PFO are three times more likely than those without a PFO to suffer another stroke, even if placed on preventive medications.

The U.S. Food and Drug Administration approved the device in early 2002 under the humanitarian device exemption for selected patients with a PFO who have a history of stroke from presumed paradoxical embolism passing through the PFO. The device has been in routine clinical use in Europe since 1996.

Cedars-Sinai Medical Center is one of the largest nonprofit academic medical centers in the Western United States. For the fifth straight two-year period, it has been named Southern California’s gold standard in health care in an independent survey. Cedars-Sinai is internationally renowned for its diagnostic and treatment capabilities and its broad spectrum of programs and services, as well as breakthrough in biomedical research and superlative medical education. Named one of the 100 "Most Wired" hospitals in health care in 2001, the Medical Center ranks among the top 10 non-university hospitals in the nation for its research activities.

Sandra Van | Cedars-Sinai Public Relations

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