Brain stents increase risk of stroke and death
21 September 2011
Stents inserted in arteries in the brain to reduce to reduce
the high risk of repeat strokes have been found instead to significantly
increase strokes and deaths in a multi-center clinical trial. The
research is reported online Sept. 7, 2011, in The New England
Journal of Medicine.
In the first month after treatment, patients with the stents
experienced more than twice the rate of strokes and deaths compared
to patients without them, prompting the US National Institute of
Neurological Disorders and Stroke to halt trial enrollment.
The US National Institutes of Health issued a clinical alert at
that time to inform doctors and the public of the study’s results.
The alert will likely shift the preferred treatment for these
patients to medications and lifestyle changes that reduce clotting
and lower blood pressure and cholesterol. The study provides a more
detailed report of what happened during the trial, which was
conducted at 50 medical centres across the US.
The 450 patients in the study had recently had strokes or
temporary stroke-like symptoms associated with significant narrowing
of a major brain artery. This narrowing reduces blood flow in the
brain and puts patients at high risk of additional strokes.
All patients received blood-thinning drugs and aggressive
treatments to lower blood pressure and cholesterol, two key risk
factors for stroke. Half the patients were randomly selected to
receive the stents.
The researchers found that nearly 15% of patients treated with
stents had a second stroke or died in the first 30 days after
treatment, while less than 6% in the control group had another
stroke or died in the same time period.
During a nearly one-year follow-up period, 20.5 percent of
patients in the stent group and 11.5 percent of patients in the
control group had a stroke or died.
“The complications on the stent side of the trial were higher
than we expected,” says co-principal investigator Colin P. Derdeyn,
MD, professor of radiology at Washington University School of
Medicine in St. Louis. “Further research may identify specific
groups of patients who may benefit from these stents, but for now we
seem to be able to save more lives by aggressively working to lower
blood pressure and cholesterol.”
The researchers are now trying to determine why patients with the
stents experienced high rates of strokes and death. Among the
possibilities are blood clots forming on the stents or breaking
loose from blood vessel walls. Damage to blood vessels during
installation of the stents may also have increased risk.
Stroke is the fourth leading cause of death in the United States.
Stenosis, a blockage or narrowing of brain arteries caused by the
buildup of plaques and clots, accounts for more than 50,000 of the
795,000 strokes that occur annually nationwide. Stenosis is
particularly common in African-Americans, Hispanics, Asian-Americans
and people with diabetes.
The only FDA-approved device for treating blocked arteries in the
brain is the Gateway-Wingspan system. This technology allows
physicians to open a blocked cranial artery by inserting a balloon
into the artery and inflating it. Next, physicians insert a stent to
keep the artery open.
Derdeyn and lead author Mark Chimowitz, MBChB, of the department
of neurosciences at the Medical University of South Carolina in
Charleston, wanted to test the risks and benefits of
Gateway-Wingspan in a randomized clinical trial. They designed the
Stenting vs. Aggressive Medical Management for Preventing Recurrent
Stroke in Intracranial Stenosis
“An earlier study found that high blood pressure and cholesterol
levels in this group of patients was strongly associated with
increased stroke risk,” Derdeyn says. “We developed ‘aggressive
medical management’ protocols that asked treating physicians to work
hard to bring patient blood pressure and cholesterol into safe
ranges. We also regularly monitored patients to see if these goals
were being met.”
“We only accepted patients whose stenoses blocked 70 percent or
more of an artery, so this was a very high-risk group,” says
Derdeyn, who is director of the Stroke and Cerebrovascular Center at
Barnes-Jewish Hospital and the School of Medicine. “While we were
selective in that regard, we did not investigate the nature of the
blockages — for example, how much of the blockage was plaque only
and how much of it was blood clot on a plaque. These patients may
have different risk of stroke with stenting.”
The researchers will continue to follow the patients who have
already been treated for two more years.
Chimowitz MI, et al. Stenting versus Aggressive Medical Therapy
for Intracranial Arterial Stenosis. N Engl J
Med 2011; 365:993-1003. September 15, 2011.
Source: Washington University in St Louis.