"It's tremendously exciting to be able to treat the diseases that cause devastating strokes--and to be able to treat them with small punctures in the skin, rather than major surgery," said Ted Feldman, MD, FSCAI, director of cardiac catheterization at Evanston Northwestern Healthcare in Evanston, IL, and program chair for the SCAI annual meeting.
Most strokes are like a heart attack that takes place in the brain. A blood clot blocks an artery, cutting off the supply of blood, oxygen, and nutrients to brain cells. In another type of stroke a blood vessel bursts, flooding an area of the brain with too much blood. In either case, brain cells begin to die. Depending on how large the stroke is and which part of the brain is damaged, a person may be left with minor weakness in an arm or leg, or may be paralyzed on one side of the body, or unable to speak.
Some 700,000 Americans suffer a stroke every year. Two out of three are left with some type of permanent disability. But there's good news, too: By some estimates, 80 percent of strokes can be prevented, and an increasing number of treatments are available for patients who have already suffered a stroke.
Interventional cardiologists are playing a central role in developing new treatments for stroke. Interventional cardiologists treat trouble spots in the heart and blood vessels with tiny balloons and expandable metal stents threaded through the body on the end of a slender tube called a catheter. Catheter treatments require only a small puncture in the skin.
One type of interventional procedure that can prevent stroke is carotid stenting. The carotid arteries in the neck are critical pathways for blood flow to the brain. Similar to arteries in the heart, they can become clogged with cholesterol deposits. Traditionally, clearing away deposits in the carotid arteries has involved major surgery. Today, a growing number of patients are instead treated by an interventional cardiologist, who threads a catheter into the neck artery, inflates a tiny balloon to push aside the cholesterol build-up, and leaves in place an expandable metal, mesh tube--a stent--to keep the artery open.
In some cases, clogged arteries of the heart can be treated in the same session, avoiding open-chest coronary artery bypass surgery. "Patients can walk out of the hospital with their blood vessels open, without having to face high-risk, major surgery," Dr. Feldman said. "They're very happy about that."
Strokes have a variety of causes, and interventional cardiologists have an array of techniques and tools to treat them. For example, some strokes are caused by a hole in the wall separating the two upper chambers of the heart. This hole--known as a PFO (short for patent foramen ovale)--plays an important role when a baby is developing in the womb. It allows blood to circulate throughout the body without first flowing through the undeveloped lungs. Once the baby is born and begins to breathe, the hole usually closes on its own--but when it doesn't, the PFO can allow blood clots to pass directly from the right side of the heart to the left, where they are pumped to the brain, causing a stroke.
Interventional cardiologists prevent PFO from causing a stroke by threading into the heart a pair of spring-loaded patches mounted on the end of a catheter. One umbrella-like patch is opened on the left side of the heart, then the catheter is pulled back into the right side of the heart, and the second patch is opened. The two are snugged together, forming a tight seal.
Another type of stroke is caused by atrial fibrillation, the most common type of abnormal heart rhythm. People with atrial fibrillation face a high risk of stroke because the upper chambers of the heart quiver, rather beating with regular, forceful contractions. This allows blood to collect in a little pouch off the left-sided upper chamber of the heart, called the left atrial appendage, or LAA. The stagnant blood forms blood clots, which can travel to the brain.
Today, most people with atrial fibrillation take blood thinners to prevent stroke. These medications are effective, but they are inconvenient to take and can cause major bleeding. People with atrial fibrillation may soon have simpler new treatment options. Interventional cardiologists are investigating a new technique that involves using a catheter to insert a small, acorn-shaped device into the opening of the left-sided pouch, permanently blocking it off and preventing blood from stagnating and clotting there.
Researchers continue to explore new ways to use interventional techniques to prevent and treat stroke. One day, for example, it may be common to open blocked arteries in the brain itself with a catheter-mounted balloon or stent--the same tools and techniques interventional cardiologists have perfected in the heart.
"Stroke is such a devastating disease. Every patient we can bring back from the brink of disability is a tremendous success," Dr. Feldman said.
Headquartered in Bethesda, Md., The Society for Cardiovascular Angiography and Interventions is a 3,400-member professional organization representing invasive and interventional cardiologists. SCAI's mission is to promote excellence in invasive and interventional cardiovascular medicine through physician education and representation, and advancement of quality standards to enhance patient care. SCAI was organized in 1976 under the guidance of Drs. F. Mason Sones and Melvin P. Judkins. The first SCAI Annual Scientific Sessions were held in Chicago in 1978.
Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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