To prevent a common type of stroke, intensive medical therapy could be better by itself than in combination with surgery that props open affected arteries. But it remains to be seen whether the apparent advantage will prove true over the long term.
The findings, from a national clinical trial conducted by University of Florida researchers and colleagues, will be published online in The New England Journal of Medicine online on Sept. 7.
Against expectations, the short-term risk of stroke and related death was twice as high in some cases for patients whose diseased arteries were widened via balloon angioplasty and stent insertion, compared with patients who received medical therapy alone. Although the 30-day risk of stroke for the stenting patients is concerning, long-term results could be more favorable, the researchers said.
"Five years from now, who will be doing better -- the patients who are being medically managed, or those who received a stent?" said study co-author Michael F. Waters, M.D., Ph.D., director of the Shands at UF Stroke Program, who along with Brian L. Hoh, M.D., the William Merz associate professor of neurological surgery in the College of Medicine, led the UF portion of the trial.
The study will have a substantial impact on clinical practice and research, the researchers said, because it is the first randomized stroke trial to pit stenting against nonsurgical treatment for symptomatic intracranial atherosclerosis, a type of stroke caused by artery blockage in the brain. Early results clearly show that intensive medical management is key to improving health, the researchers said.
"This study provides an answer to a longstanding question by physicians -- what to do to prevent a devastating second stroke in a high-risk population. Although technological advances have brought intracranial stenting into practice, we have now learned that when tested in a large group this particular device did not lead to a better health outcome," said Walter Koroshetz, M.D., deputy director of the NIH National Institute of Neurological Disorders and Stroke, which funded the clinical trial.
Every 40 seconds, someone in the U.S. has a stroke. Stroke is the fourth leading cause of death and a leading cause of disability in the U.S. Almost 800,000 people a year have a new or recurring stroke, according to the American Heart Association. With higher than average rates of stroke and related deaths, parts of the southeastern U.S. are together termed the "Stroke Belt."
Patients with the type of stroke known as symptomatic intracranial atherosclerosis do not respond well to existing treatments. One-quarter of those patients have another stroke within 12 months, and the risk of additional strokes continues in subsequent years. Doctors are unsure what the best course of treatment is.
To find out, the UF researchers and colleagues launched a clinical trial, nicknamed SAMMPRIS, at 50 sites around the country, including at the Medical University of South Carolina, the lead site. The study recruited 451 participants age 30 to 80 who had at least 70 percent narrowing in the arteries in the brain, and had experienced symptoms within the previous 30 days. UF recruited the second-highest number of patients among all sites, through its stroke program, which has been designated a Comprehensive Stroke Center by the Agency for Health Care Administration.
Patients in one group were randomly assigned to receive intensive management involving smoking cessation and medications for blood pressure, cholesterol, diabetes and blood-clot prevention. A second group of patients had that same medical treatment but also had balloon angioplasty and stent implantation into the affected brain artery to improve blood flow.
Almost 15 percent of patients who received stents had a stroke or died within 30 days of enrolling in the study, compared with just under 6 percent of patients in the medical therapy group. The stark difference between the groups persisted almost a year, by which time about 21 percent of patients who had received stents had had negative effects, compared with 12 percent in the medical group.
The researchers initially thought that patients who received stents would have fared better, given the successful use of similar procedures in clinical practice at the Shands at UF Stroke Program and other medical centers.
But the striking difference between the two patient groups prompted the study's independent safety monitoring body to call off new recruitment. The researchers will, however, continue to monitor previously enrolled patients for the next two years.
It's not unusual for surgical patients to have more complications at first, the researchers said. That's because the invasiveness of surgery poses an inherent risk regardless of the illness being treated.
"The real question is, is there a benefit to patients over the long term," said study co-author and co-principal investigator Hoh, who is an associate professor of radiology and neuroscience in the UF College of Medicine. "If you think about it, when people are concerned about stroke, it's not just their first month that matters, so we're waiting to see what the longer-term results will be."
Over time, improvement of stent design and honing of surgical techniques could help improve outcomes for patients.
"This is certainly not the final say on managing this disease," Waters said. "This is another piece of the puzzle that helps to guide our hand."
- Marc I. Chimowitz, Michael J. Lynn, Colin P. Derdeyn, Tanya N. Turan, David Fiorella, Bethany F. Lane, L. Scott Janis, Helmi L. Lutsep, Stanley L. Barnwell, Michael F. Waters, Brian L. Hoh, J. Maurice Hourihane, Elad I. Levy, Andrei V. Alexandrov, Mark R. Harrigan, David Chiu, Richard P. Klucznik, Joni M. Clark, Cameron G. McDougall, Mark D. Johnson, G. Lee Pride, Michel T. Torbey, Osama O. Zaidat, Zoran Rumboldt, Harry J. Cloft. Stenting versus Aggressive Medical Therapy for Intracranial Arterial Stenosis. New England Journal of Medicine, 2011; 110907123845030 DOI: 10.1056/NEJMoa1105335
- Joseph P. Broderick. The Challenges of Intracranial Revascularization for Stroke Prevention. New England Journal of Medicine, 2011; 110907082203013 DOI: 10.1056/NEJMe1108394
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