In the largest and reportedly most clinically detailed population-
based study of carotid endarterectomy to date, researchers outline 11
risk factors for poor outcomes. The results appear online October 23
in Stroke and are expected to influence guideline updates.

"Carotid revascularization is very much a time trade-off," lead
investigator Ethan Halm, MD, from the University of Texas
Southwestern Medical Center, in Dallas, told Medscape Neurology &
Neurosurgery. "We don't want to cause a stroke to prevent a stroke,"
he said.

New endovascular procedures for treating internal carotid artery
stenosis with angioplasty and stenting techniques are growing in
popularity but are controversial.

Researchers point out that although the results of randomized
controlled trials comparing stenting with carotid surgery are mixed
and the appropriate role for stenting is uncertain, it is largely
promoted as an option for patients who are considered high risk or
too old or too sick to safely undergo carotid endarterectomy.

This underscores the need for empirically validated data on risk
factors for perioperative death or stroke after surgery," they write.

Known as the New York Carotid Artery Surgery Study, this new
initiative includes more than 9300 patients. Carotid endarterectomies
were performed by 482 surgeons in 167 hospitals.

Investigators obtained clinical data from medical charts to assess
sociodemographic, neurological, and comorbidity risk factors. Dr.
Halm and his team developed a multivariable model predicting the risk
for death or stroke within 30 days of carotid endarterectomy.

Asymptomatic Patients Not Necessarily Low Risk

Most previous studies focused on differences in complications between
patients operated for symptomatic vs asymptomatic carotid disease.
These new results confirm the well-documented finding that
symptomatic patients have twice the risk for perioperative death or
stroke. But it raises important new issues as well.

These studies and current national guidelines largely consider
asymptomatic patients a homogenous low-risk group. This new finding
suggests otherwise.

"Asymptomatic patients with a history of distant cerebrovascular
disease have one-third higher risk-adjusted complication rates
compared with patients with no history of stroke or [transient
ischemic attack] TIA," Dr. Halm said during an interview. "This is
important because three-quarters of carotid endarterectomies in the
United States are performed in asymptomatic patients, and these
patients have less to gain from surgery."

The presence of a deep carotid ulcer was of borderline significance,
with an odds ratio of 2.08 (95% CI, 0.93 ¡V 4.68).

The investigators point to several limitations to their work,
including the study's observational cohort design. As a result,
researchers relied on information on risk factors and complications
documented in medical records. There was no standard approach to pre-
or postsurgical assessment as could have been done in a prospective
trial.

"These results have several practical implications," Dr. Halm
said. "From a clinical standpoint, information about risk factors
should help referring physicians, neurologists, surgeons, and
anesthesiologists better weigh the risks and benefits of carotid
endarterectomy for an individual patient."

He explained, "This prognostic information may also help identify
those who might be considered potential candidates for carotid
stenting because they are too high risk for carotid endarterectomy."