UW-Madison Surgeon: Carotid Stents Can Be Risky for Some Patients

Madison, Wisconsin - For patients who have already had a "mini" or major stroke, opening the carotid artery with a stent triples their risk of death compared with the older method of clearing the blocked artery with surgery, a large population study reports.

But for patients without symptoms who receive treatment to prevent a stroke, the less invasive method of inserting a stent via the blood vessels has results that are identical to surgery.

"The results made us very convinced that you should not have a stent procedure if you're symptomatic," says Dr. K. Craig Kent, chair of surgery at the University of Wisconsin School of Medicine and Public Health.

Kent and his colleagues from the medical schools at Mount Sinai, Cornell and Columbia universities studied the results from 47,752 patients who had the procedures from 2005 to 2007 in California and New York.

Kent, the senior author of the study, says the goal was to settle the question of whether the newer method of carotid artery stenting - in which a wire mesh tube is inserted into the neck artery to open it and prevent re-blockage - had similar outcomes to the older method, a carotid endarterectomy, in which the plaque is surgically removed.

The study found that the results depend on the history of the patients.

Patients who had already had a stroke - or a mini-stroke, also called a TIA or transient ischemic attack - in which plaque broke off and impeded blood flow in the brain, did far worse when their blocked carotid arteries were stented.

The study found that 3.7 percent of those symptomatic patients died during the stenting procedure. The combined rate of stroke or death was higher, too, at 8.3 percent, for stent patients who had a previous stroke.

"The different outcomes make sense if you consider the technique," Kent says. "Patients who have already experienced stroke symptoms have plaque that has become unstable and has begun to break off. In other words, placing the stent could, in some cases, dislodge unstable plaque and send it to the brain, causing stroke and possibly death. Thus, a stent may be safer in a patient with a stable plaque that hasn't produced symptoms."

"Our finding of a dramatic and significant increased risk of stroke and death in symptomatic patients undergoing (stenting) warrants re-evaluation of the patient population that may indeed benefit from this intervention," Kent and colleagues write. "Ironically, at this point in time, the only reimbursed indication for stenting is for high-risk symptomatic patients."

But for the 70 percent of patients who had blocked arteries but had not yet had strokes, the news was better: the two approaches had statistically identical outcomes.

And Kent notes that patients tend to prefer the less invasive stenting procedure. A stent is inserted into an artery in the thigh and threaded to the neck from there.