Minimizing stroke risk
Stents give patients with carotid artery stenosis a second chance at life
By Darla Brown
With two clogged carotid arteries and a brain aneurysm,
Bob Pruett was a man in desperate need of medical care. But even in Houston,
home to the world’s largest medical center, he was having trouble
“I was turned down by four neurosurgeons because I was too high of a risk
because of my carotid arteries,” he recalls.
Pruett was at the end of the line when he turned to cardiologist Richard Smalling,
“I was completely without hope and didn’t feel like I could go on
anymore,” he says. “I would have signed a pact with Satan.”
Fortunately, Pruett only had to sign consent forms – he was approved as
a participant in a clinical trial for high-risk surgical patients with carotid
artery stenosis – the narrowing of the arteries leading to the brain.
Dr. Smalling is the primary investigator for the UT Medical School/Memorial Hermann
Hospital site of a national study called BEACH (Boston Scientific EPI-A Carotid
Stenting Trial for High Risk Surgical Patients), which is testing a new type
of carotid artery stent.
Carotid stenting is a 20-minute procedure carried out with local anesthetic.
The clinician threads a fine wire with a miniature umbrella-like filter into
the carotid artery via the groin. The filter opens up beyond the blockage to
catch any pieces that may break off during the procedure. A standard angioplasty-type
balloon is then used to gently dilate the blockage, and a self-expanding wire-mesh
stent is inserted to keep the dilated area in the artery from collapsing.
“After you’re finished working on the artery, you can go back up
and retrieve the filter and its caught material, which is caught instead of traveling
up to the brain to cause a stroke,” Dr. Smalling explains.
Both of Pruett’s carotid arteries were stented with the study device – one
was 70 percent blocked and the other one was 50 percent blocked – during
“The BEACH study uses a different type of filter and a different type of
wire-mesh stent compared to other devices currently being used for this procedure.
Each company has to prove their stent produces similar results to other results,” Dr.
Eighteen months after the second stent, Pruett says he is a new man. “I
am not the same man I was – I was overweight, depressed. This program has
saved my life, and I’m so thankful for Dr. Smalling and his staff,” he
says. “This gave me a second chance at life.”
Focus on stenting
Carotid artery stenosis, due usually to a build up of plaque, is responsible
for up to 25 percent of strokes. For years, surgery – carotid endarterectomy – has
been the gold standard for treating patients with blocked carotid arteries.
“Now the focus is on stenting,” says Dr. Smalling, interim director
of the Division of Cardiology. “We got started with stenting carotid
arteries in the mid- to late-1990s because there were always some patients
who were not good candidates for carotid endarterectomy who might be better
served with carotid stenting.”
Patients with lung and heart disease, or those who have major blockage in
both arteries, are considered high risk for surgery and therefore good stent
anyone with prior radiation therapy to their neck are dangerous to operate
on, so they are better candidates for stenting,” Dr. Smalling adds.
Stents also are implanted in patients who have developed a renarrowing
of the arteries following an earlier carotid endarterectomy.
“It’s not uncommon – 10-15 percent of our patients are referred
to us by vascular surgeons because their patients have developed renarrowing
of the artery,” Dr. Smalling says.
A team effort
Since the carotid arteries bring blood flow to the brain, and the risk
of stroke in these patients is a real threat, Dr. Smalling works in
collaboration with James C. Grotta, M.D., John Choi, M.D., and other
members of the UT Stroke Team.
“From the beginning we were very careful that the neurologist who deals
with this for a living is reviewing these cases, determining what needs to be
done,” Dr. Smalling explains. “It’s important to have the blessing
of the Stroke Team.”
“Stroke Team members evaluate patients and are on site doing transcranial
Doppler monitoring and neurological monitoring during the stenting procedure,” says
Dr. Choi, assistant professor of neurology.
The team involved with these types of patients includes research nurses, fellows,
the catheter lab team, and clinicians in the Departments of Diagnostic and
Interventional Imaging and Cardiothoracic and Vascular Surgery.
“Having a multidisciplinary team involved is best for the patient. People
with carotid blockage usually have cardiac blockage, so cardiologists are in
the best position for primary care; then follow-up care after carotid surgery
or stenting is with a neurologist,” Dr. Choi says.
Stents vs. surgery
Risks are associated with both carotid endarterectomy and carotid stenting.
“Each technique has its pros and cons. Five years ago, there was a high
complication rate for stenting, but we’ve been working hard to reduce that,” Dr.
The stroke rate is around 2 percent for those who receive stents – the
same rate as asymptomatic patients who receive the surgery.
“We’ve been very lucky over the years – we’ve had 150
carotid stent patients and no strokes. All of our patients go to the cardiac
care unit after the procedure because of potential heart and blood pressure changes
that settle out after the first 24 hours. The heart attack rate is essentially
zero with a cardiologist doing the procedure and paying a lot of attention to
heart function,” Dr. Smalling says, adding that there was one death early
in the team’s experience that was not related to the stenting.
Stent patients typically spend one night in the hospital compared to three
or four nights necessary for those undergoing carotid endarterectomy.
Randomized trials so far have shown a 50 percent reduction in the complication
rate of patients with carotid stenting compared to those who have the surgery. “The
risk of renarrowing in a stented area is less than 4 percent – compared
to surgery, which is about 10 percent,” Dr. Smalling says. “But
there have been no head-to-head comparisons in large numbers of patients to
evaluate the risks of the two procedures.”
The CREST trial (Carotid Revascularization Endarterectomy vs. Stent Trial)
is looking at viable surgery candidates who are then randomized to either
surgery or stent. Dr. Choi is the primary investigator on the study, and
co-investigators are Hazim Safi, M.D., chair of the Department of Cardiothoracic
and Vascular Surgery, and George Letsou, M.D., associate professor of cardiothoracic
and vascular surgery.
Sponsored by the National Institutes of Health, CREST will involve 2,500
patients to evaluate the outcomes between these procedures.
“It’s important to test stenting against carotid surgery, which has
been tried and proven since the late 1960s, when Dr. Michael DeBakey was one
of the first to publish on removing blockage from the carotid artery through
surgery,” Dr. Choi says.
Results so far show that those patients 80 years and older have more complications
with stenting. “But these patients weren’t candidates for surgery
prior to this trial anyway,” Dr. Choi says, adding that this is one of
the first clinical trials looking at benefits from either procedure in older
Future of stents
Presently, carotid stenting is done in a small percentage of patients
due primarily to the small number of certified operators. Vascular
training programs are now teaching clinicians how to stent carotid
As the techniques and equipment evolves and becomes standardized, outcomes
in carotid stenting will continue to improve, Dr. Smalling says. “Who
knows what could be possible in the future – maybe robots instead of
balloons – but right now the technology is stents.”
Even though stenting appears to be the more patient-friendly choice, don’t
count out the future of carotid endarterectomy just yet.
“If stenting can be shown to have equivalent or less risks, patients will
opt for it, but surgery won’t completely go away,” Dr. Choi says.
The risk is that the pendulum could swing too far.
“There is a saying that to someone with a hammer, everything looks like
a nail. The analogy is: To an interventionalist with a balloon, everything
looks like a stenosis or blockage,” Dr. Smalling says. “The great
worry is that once carotid stenting gets into the mainstream, anyone with even
a minor blockage in a carotid artery will wind up with a stent, and that could
quite possible lead to an increase event rate rather than a decrease in stroke.”