The final results of a stroke prevention study in patients with narrowed brain arteries have confirmed earlier findings: medication plus lifestyle changes are safer and more effective at preventing stroke than a surgical technique called stenting.
The study appears in the Oct. 26 edition of The Lancet. The study analyzed long-term health outcomes from a multicenter clinical trial. Oregon Health & Science University's Oregon Stroke Center was the top enroller in the trial; 27 OHSU stroke patients participated in the study.
Enrollment in the trial across all sites was halted two years ago when it became apparent that stenting was associated with a higher risk of early strokes and death.
"The study found that people at risk of stroke who managed their condition medically — by aggressively treating their risk factors and taking certain blood-thinning medications — on the whole did better than those who underwent the stent procedure and used medical therapies," said Helmi Lutsep, M.D., vice chair of neurology at OHSU, a stroke specialist at OHSU's stroke center and a co-author of the study. "In the group that used medical therapies alone, there were fewer strokes and deaths in the first month of the trial than in the stenting group. Beyond the first month, the rates of stroke were the same in each group."
“Surgical interventions often have increased risk of complications early on, so we continued to follow the patients to see if the long-term effects of surgery were beneficial,” said the study's lead author, Colin Derdeyn, M.D., professor of radiology at Washington University School of Medicine in St. Louis. “That did not turn out to be the case.”
The study was led by researchers at Washington University School of Medicine in St. Louis, the Medical University of South Carolina, Emory University and the State University of New York at Stony Brook. On the same day the study appears in The Lancet, the researchers will present their findings at the joint meetings of the sixth International Conference on Intracranial Atherosclerosis and the sixth annual meeting of the Society of Vascular and Interventional Neurology in Houston.
Each year in the United States, about 800,000 people have a stroke. Physicians think that about 10 percent of those strokes result from a narrowed artery inside the brain.
For decades, doctors have treated these patients with medications that help prevent clot formation by thinning the blood and with drugs to lower cholesterol and blood pressure. Recent advances in surgical techniques and tools have allowed physicians to improve blood flow in narrowed brain arteries by adapting procedures used to open clogged arteries in the heart.
To assess the effectiveness of the new treatments, the trial — called Stenting and Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis, or SAMMPRIS — enrolled 451 patients at high risk of repeated stroke. The trial was funded by the National Institutes of Health. All participants had a brain artery with at least a 70 percent narrowing that had already caused a stroke or a transient ischemic event (often referred to as a mini stroke).
Participants were divided into two groups. In one group, each participant had a metal stent surgically inserted into the narrowed brain artery to open the artery. Each also received strong medications to reduce clot formation and lower cholesterol and blood pressure. Participants in the second group received the same medications but did not receive stent implants. Both groups were contacted regularly by lifestyle modification coaches, who encouraged participants to exercise more, stop smoking, improve their diet and lose weight.
For the final analysis, the scientists followed the patients for at least two years after treatment. Some patients were followed for as long as four years.
“We were expecting that at some point the incidence of new strokes in those who had surgery would drop below that of those who did not, but that didn’t happen,” Derdeyn said.
“Stenting of brain arteries had been performed throughout the U.S. for many years without enough evidence for its effectiveness at reducing the risk of stroke. At OHSU, we felt it was very important to take part in this trial so a definitive answer could be obtained about how best to manage these patients,” said Stanley Barnwell, M.D., Ph.D., associate professor of neurological surgery and diagnostic radiology at OHSU and also a co-author of the study. “Cardiologists had done this many years ago in regards to heart angioplasty and stenting, but similar data were missing in the cerebrovascular field. This study clearly showed that exercising more, stopping smoking, improving diet and losing weight are better choices than intracranial stents. There may still be a sub-population of patients that would benefit from this procedure, but selection of those patients must be very carefully done.”
In August 2012 the early results of SAMMPRIS led the Food and Drug Administration to alter the criteria for using the "wingspan" stent tested in the trial. The new guidelines restricted the use of stenting to patients with severe blockage who had had two previous strokes while on aggressive medical management.
This small subset of high-risk stroke patients was not specifically assessed in the trial. But the study did compare stenting with medical therapy in several other subsets and did not identify any subset that benefited more from stenting than medical therapy.
OHSU's Oregon Stroke Center, earlier this year named one of a few dozen comprehensive stroke centers in the United States by the Joint Commission, was among 50 stroke centers that participated in the study.
The study was funded by the U.S. Public Health Service National Institute of Neurological Disorders and Stroke (U01 N5058728), and Clinical and Translational Science Awards from the National Institutes of Health to the Medical University of South Carolina (UL1RR029882), the University of Florida (UL1RR029889), the University of Cincinnati (UL1RR029890) and the University of California, San Francisco (UL1RR024131). Stryker Neurovascular (formerly Boston Scientific Neurovascular) provided study devices and supplemental funding for aspects of the study.