To prevent stroke in certain high-risk patients—those with a blocked neck (carotid) artery who have already had a so-called "mini-stroke"—drug treatment appears as effective and far less risky than bypass surgery, researchers find.
Their study evaluated nearly 200 patients, about half of whom had carotid artery bypass surgery. In the 30 days after surgery, patients had a 14% risk of having a stroke, compared with a 2% risk among those treated medically, the study found.
The study was published in the Journal of the American Medical Association.
About Carotid Artery Bypass Surgery
The surgical procedure is called extracranial-intracranial arterial bypass surgery. It involves drilling a hole in the head and attaching a blood vessel from the scalp to one of the blood vessels of the brain, bypassing the blockage in the neck, explained lead researcher William J. Powers, MD, chairman of adult neurology at the University of North Carolina School of Medicine, at Chapel Hill.
In the trial, called the Carotid Occlusion Surgery Study, Dr. Powers' team randomly assigned 195 patients to carotid bypass surgery or medical management. The patients were at a high risk of having a stroke, with a 23% risk of having one within two years, according to Dr. Powers.
Based on early findings, the trial was stopped. Over a two-year period, the researchers found that 21% of the patients who had surgery died or had a stroke, compared with 22.7% of those on medical therapy alone-which is not a significant difference, Dr. Powers said.
Moreover, at 30 days after surgery, 14.4% of the surgical patients had a stroke, compared with 2% of those on medical therapy. That's a 12.4% difference, the study group noted.
"We were trying to figure out a way of taking people who were at high risk of having stroke and prevent that from happening," said Dr. Powers. "The unfortunate part is that we didn't do that," he added. "If you made it through the surgery, your risk of having a stroke was 6%, but, unfortunately, the risk of having a stroke from surgery was 15%," he said. “This procedure should not be used for this purpose."
Dr. Powers added that despite this failure, they are still looking for a safer way to get blood to the brain in patients who have a completely blocked carotid artery, the large blood vessel in the neck. "We are hoping to take what we learned and take the same type of patients and try a catheter stent-based approach," he said.
Commenting on the study, Ralph Sacco, MD, chairman of neurology at the University of Miami Miller School of Medicine and past president of the American Heart Association, said "medical therapy with anti-clotting drugs, blood pressure and cholesterol-lowering drugs has improved over the years, which makes it more effective.
"Current guidelines would say there is no indication for pursuing a bypass in these patients," Dr. Sacco added. "The Heart Association says the procedures should be done with less than a 6% perioperative risk in symptomatic patients and 3% in asymptomatic patients." Perioperative refers to the period of hospitalization for surgery.
Looking at a larger picture, Joseph P. Broderick, MD, chair of neurology at the University of Cincinnati College of Medicine and coauthor of an accompanying journal editorial, said the effectiveness of any new therapy needs to be demonstrated before it can be used.
"Potential new therapies, particularly surgical procedures that use devices to reopen blocked arteries, need to be tested against the standard proven approach of intravenous tPA sa drug that breaks up clots and is standard therapy for stroke)," he said.
Yet, these devices are already being used in clinical practice since they have been cleared by the Food and Drug Administration (FDA) for use and are currently reimbursed by Medicare for acute stroke treatment despite a lack of evidence that they improve outcomes as compared to standard therapy, Dr. Broderick said.
This happens because the rules for FDA approval and Medicare reimbursement of devices are different from the rules for approving drugs, he said. This makes it harder to get people to take part in clinical trials of devices, because they are in use before they are clinically proven to work, he added.