Features February 2011 Issue

Stroke Prevention Guidelines Look at Carotid Artery Treatments

Updated guidelines also focus on cholesterol and blood pressure control.

If you have ever had a stroke or transient ischemic attack (TIA, a temporary event with stroke-like symptoms that does not cause†lasting brain damage), your doctor has probably told you that your risk for a subsequent cerebrovascular event is higher than it would be for someone who has never experienced one.

With that in mind, the American Heart Association (AHA) and American Stroke Association (ASA) recently updated their guidelines for the prevention of secondary strokes. The recommendations focus on minimizing the factors that comprise metabolic syndrome, careful use of antiplatelet drug therapy and treatment of narrowed carotid arteries, which are often implicated in ischemic strokesóthose caused by blockage in the arteries carrying oxygen-rich blood to the brain.

Cleveland Clinic neurologist and stroke specialist Stefan Dupont, MD, says secondary stroke prevention should also be geared toward the cause, if known, of your first stroke. About 800,000 Americans suffer a stroke annually, and about one in four of those events are recurrent strokes, he says.

"A TIA or a stroke is never an isolated event," Dr. Dupont says. "After the first stroke, the risk of having another one is increased by four percent the first month, 12 percent the first year and 30 percent by five years. The more precise risk of stroke recurrence depends on the cause of the first stroke, so treatment modalities aimed at reducing the risk of stroke recurrence may be different in each case."

Dr. Dupont adds that, despite the best efforts of physicians, a cause of stroke or TIA cannot be determined in about 30 percent of patients.

But a good place to start looking is at the health of the carotid arteries, which run up both sides of the neck to connect with smaller arteries in the brain.

Carotid Artery Treatment

The carotid arteries carry oxygen-rich blood to the brain, but narrowing of those arteries can present significant stroke risks. The new guidelines suggest that carotid angioplasty, a minimally invasive procedure that places a stent in the narrowed portion of the artery, may be an effective alternative for stroke survivors who are facing carotid artery stenosis. Surgically opening up a carotid artery and removing the plaque inside is a procedure called an endarterectomy.

Dr. Dupont notes that a patient with carotid artery narrowing is also likely to have coronary artery disease and reduced cardiac reserve.

"Surgery under general anesthesia is not without risk," he explains. "Carotid artery stenting provides an alternative to carotid endarterectomy for the treatment of high-grade carotid stenosis. The procedure is less-invasive, requires only local anesthetics and reduces the risk of cranial nerve damage."

Dr. Dupont adds, however that the long-term durability of carotid artery stenting hasnít been established. Carotid endarterectomy is preferred if it can be done safely.

Lifestyle Adjustments

Among the cornerstones of stroke prevention are lifestyle adjustments aimed at controlling several risk factors. In addition to the secondary stroke prevention guidelines updated in 2010, the AHA and ASA also updated their primary stroke prevention guidelines to help protect against a first-time event.

In both sets of recommendations, individuals are urged to manage the factors that comprise metabolic syndrome, a cluster of risk factors such as high blood pressure, abnormal cholesterol levels, excess fat around the waist and high blood sugar levels.

Having metabolic syndrome increases your odds of a heart attack, stroke or developing diabetes. The guidelines suggest that screening individuals for metabolic syndrome may not be as effective as addressing individual risk factors.

"Each component by itself is a risk factor, so classification of patients according to metabolic syndrome doesnít seem to add much value in the estimation of stroke risk, as long as the individual components are properly addressed," Dr. Dupont says. "And weight loss leads to improvement in all features of metabolic syndrome."

Medical Therapy

Though lifestyle adjustments and proactive carotid artery treatments are keys to secondary stroke prevention, medications, specifically antiplatelet agents, are essential forms of treatment for most stroke survivors and anyone else at high risk of a cerebrovascular event.

Dr. Dupont notes that antiplatelet drugs reduce the relative risk of stroke recurrence and that the combination of aspirin and dipyridamole (Aggrenox) seems to be more effective than aspirin alone.

The guidelines stress the importance of medical therapy tailored to each individual patientís needs and overall health concerns.

Dr. Dupont notes that other medical conditions may influence what drugs are appropriate, based on the risks of side effects and other drug interactions.

"Selection from among FDA-approved agents is mainly based on relative effectiveness, side effects,costs, patient characteristics and patient preference," he says. "This leads to a great degree of treatment variability among stroke patients."