A safer stent for stroke prevention

Karthikeshwar Kasirajan with stent

 A new procedure performed by Emory doctors can unclog the carotid artery and at the same time prevent any plaque from reaching the brain.

by Kay Torrance

Some stroke patients never seem like themselves afterward. In time, their behavior changes. They become short-tempered, forgetful, confused.

Vascular dementia, as it is known in stroke patients, mirrors the symptoms of Alzheimer's disease—the mood swings, the loss of recognition of familiar places and faces, the sometimes inappropriate behavior. While Alzheimer's is better known, vascular dementia is gaining a new foothold in an aging baby boomer population, with more than 5 million people suffering a stroke in 2005. Right now, one in four people who have a stroke go on to develop vascular dementia within three months, according to the Alzheimer's Disease Society.

Researchers are paying increasing attention to the connection between stroke and dementia. During a stroke, plaque clogs the carotid artery that runs from the heart to the brain, impeding the flow of blood. However, a popular treatment to unclog the artery may in turn predispose stroke patients to vascular dementia.

Commonly, stroke patients are treated with angioplasty. During the procedure, a balloon is inserted into the carotid artery to compress the plaque and widen the passageway. Unless the artery is too small, doctors usually place a fine mesh tube, called a stent, into the artery to support the arterial walls and reduce the chance that the artery will close. A filter is put in place to remove large pieces of plaque from the blood that could reach the brain and cause a stroke.



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The procedure, however, still allows tiny pieces of plaque, 100 microns or less, to reach the brain. Although that amount of plaque fails to cause stroke or dementia outright, researchers now believe the presence of plaque in the brain can predispose a person to vascular dementia in five to 10 years. A new procedure performed by Emory doctors can unclog the carotid artery and, at the same time, prevent any plaque from reaching the brain.

In a clinical trial to test the Parodi antiembolism system (PAES), a device is inserted in the artery, and a balloon is inflated just below the clogged portion. "This prevents forward blood flow to the brain during the angioplasty and stenting, thereby preventing any plaque from reaching the brain," says Karthikeshwar Kasirajan, (above), an Emory vascular surgeon who uses the PAES, which is also known as NPS, or neuro protection system.

With this approach, a second catheter is inserted in a vein near the femoral artery that allows for reversal of the blood flow. As the blood travels in the opposite direction, surgeons essentially siphon the blood, filtering out all the plaque before returning it to the body through the femoral vein. Because there is no plaque reaching the brain, a patient's chance of having a stroke is greatly reduced.

Clinical trials led by vascular surgeon Juan Parodi, who invented PAES, showed less than 2% stroke occurrence with the carotid stent with retrograde blood flow. By comparison, patients who underwent carotid stenting with a distal filter had a stroke rate of 9.6%.

In a second NPS clinical trial in which Emory participated, 40 patients received the flow reversal system. All are doing well, says Kasirajan, who trained with Parodi at Cleveland Clinic.