An Arsenal Of New Weapons Against StrokeBarbara Buell
For years, there was little urgency in the treatment of stroke--often caused when a clogged artery chokes off blood flow to part of the brain--because it was believed there wasn't much doctors could do. Ambulance drivers picked up heart attack and stab-wound victims first, then the stroke cases. "Physicians used to be taught this was the way patients like grandma were supposed to die," says neurosurgeon Michael Walker, a director of the National Institute of Neurological Disorders & Stroke (NINDS).
Now, all that is changing. Better preventive therapies and education are heading off many strokes before they strike. And once they occur, doctors are starting to think of strokes in more dramatic terms: a brain attack to be treated as an emergency. This major change in thinking is taking shape because clot-busting drugs, intriguing neuroprotective agents that guard against the brain-cell death that robs victims of mobility, speech, or memory, and advanced surgical techniques are improving the outlook for survivors.
"It's the most exciting time in the history of stroke treatment," says Gary Houser, vice-president of the National Stroke Assn. "We are on the threshold of having a true treatment that can be used after the onset of symptoms."
Big numbers are driving the surge of interest in stroke treatments. More than 550,000 people have a stroke each year in the U.S., making it the third-leading cause of death. Of those half-million victims, 150,000 die. The remaining 400,000 endure handicaps, making stroke the chief cause of disability. These numbers are expected to increase as boomers age.
What are the chances you might become an unlucky statistic? Topping the list of risk factors are high blood pressure, high cholesterol, family stroke history, taking high-dose estrogen oral contraceptives, heart disease, diabetes, smoking, consuming more than two drinks of alcohol daily, using illicit drugs such as cocaine, and being more than 30% over your optimum weight. Stroke doesn't happen only to the elderly, either: About 28% of all stroke victims are under 65.
More worrisome than risk factors are warning signs. These include temporary numbness, weakness, or paralysis of the face or limbs, especially on one side. Other hints of trouble are loss of balance, sudden blurred or decreased vision, difficulty speaking or understanding simple statements, and sudden severe headache for no apparent reason. Some of these incidents, known as transient ischemic attacks (TIA), may pass within a few moments. But physicians recommend a trip to the emergency room. Don't wait until Monday morning to call your internist. If it happens, it's impossible to tell whether it's a TIA or a stroke. Quick action is essential, because researchers have discovered that there is a crucial six-hour window of time after stroke during which newly developed treatments can halt cell death. "Beyond that, damage to the imperiled or injured brain is irreversible," says Houser.
CLOT-BUSTERS. Once a stroke hits, brain cells begin to die and release chemicals that set off a chain reaction endangering cells in the surrounding area called the penumbra, where the blood supply may have been reduced but not cut off. Without emergency treatment, the larger area of cells will also die. But many hospitals are now experimenting with two types of compounds that, if administered quickly, may dissolve clots or protect cells from imminent destruction.
The clot-busters, such as Genentech's tissue plasminogen activator (TPA), have the potential to revolutionize treatment by restoring blood flow before massive damage is done. Although already used for heart attacks, TPA remains controversial for stroke because it can cause serious bleeding. Neurologist Gregory W. Albers, director of the Stroke Center at Stanford University Medical Center, is participating in a study of 200 patients who receive TPA within five hours of their stroke symptoms. Because it is a double-blind study, Albers doesn't know which patients get TPA and which receive placebos but recover spontaneously. Nevertheless, he remains hopeful: "We've had a number of patients whose strokes have disappeared within 6 to 12 hours after treatment."
Another class of compounds, called neuroprotective agents, can shield irreplaceable brain cells by blocking the deadly advance of calcium that occurs when glutamate levels rise during a stroke. Other protectants, called lazaroids, include compounds such as Upjohn's tirilazad, which helps prevent cell breakdown during stroke. While these agents may stanch the damage in the early hours after stroke, their efficacy is still unproved. Warns Albers: "It will be at least five years before these are in everyone's hospital pharmacy."
Meanwhile, advances in surgery and interventional neuroradiology are now astoundingly effective--and you can use them before a stroke hits. Last fall, the results of a study on carotid endarterectomy, the removal of fatty deposits from the neck artery that carries blood to the brain, were so compelling that NINDS cut short its $20 million study. It recommended considering surgery even for patients with no symptoms--but who had a 60% or more narrowing of the carotid artery. Based on a trial of 1,662 men and women between the ages of 40 and 79, the study showed that the risk of stroke was reduced by 55% in patients who had the elective surgery.
SPECIALIST CHECK. Carotid endarterectomy has been performed since the '50s on patients with severe blockages. In the '80s, surgeons came under scrutiny for doing too many of these risky surgeries. But better patient selection and advances in diagnostics, anesthesia, and surgery have lowered the risks. "There have been a lot of technical improvements to make the operation safer," says Wesley Moore, chief of vascular surgery at the University of California at Los Angeles. NINDS recommends using only a surgeon whose complication rate (death or stroke during surgery) is less than 3%.
But if you experience no symptoms, how do you know what shape your neck arteries are in? Simply ask your physician to listen to your neck with a stethoscope during your next checkup. The detection of a swishing sound should prompt your doctor to order an ultrasound and other tests to measure any possible narrowing. Also important: Check out either vascular surgeons or neurosurgeons who have 50 or more carotid endarterectomies under their belts. If surgeons merely quote the medical literature and can't cite their own statistics, they may not be doing enough surgeries to be skilled in the delicate task of removing the blockages without breaking off some and inducing a stroke. Experts say it's best to go to a center where large numbers of the procedure are done, such as New York's Columbia-Presbyterian Neurological Institute or Barrow Neurological Institute in Phoenix.
Interventional neuroradiologists are also pioneering less invasive, nonsurgical techniques for brain rescue. To repair an aneurysm, a bulb-like weakening in the wall deep inside the brain, before it bursts--a feat unthinkable 10 years ago--physicians today use sophisticated imaging technology that lets them guide tiny platinum coils through a groin artery up to the brain. The coils are pushed into the aneurysm, which then clots off. Angioplasty, in which a small balloon in the arteries opens narrowed vessels, is also making its way from the heart to the neck and brain. It is sometimes used with TPA, which is injected directly into the narrowed site.
Remember that lifestyle changes such as a healthier diet and exercise help decrease your chances of a stroke, and a host of common medications can reduce blood pressure, thin the blood, and prevent clots. So while there's still no single cure for stroke, people with risk factors are no longer fated to succumb to this common and cruel affliction.
Where to Find Out More
NATIONAL INSTITUTE OF NEUROLOGICAL DISORDERS & STROKE
Office of Scientific & Health Reports
Building 31, Room 8A-06
31 Center Drive MSC-2540
20892-2540, 800 352-9424 THE NATIONAL STROKE ASSN.
8480 East Orchard Road, Suite 1000,
Englewood, Colo. 80111-5015,
800 STROKES AMERICAN HEART ASSN.
7272 Greenville Ave.
Dallas, Tex. 75231
800 242-8721 (prevention and treatment)
800-553-6321 (survivors and families)