According to the authors,
treatment options for patients with significant carotid atherosclerosis include
carotid endarterectomy (CEA), carotid artery stenting (CAS), and medical
therapy. This is an analysis of results from the Stenting and Angioplasty with
Protection in Patients at High-Risk for Endarterectomy (SAPPHIRE) randomized
trial, which examined patients at higher surgical risk to determine factors
predictive of death or stroke within 30 days of CAS. A new study gives guidance on patient features that identify patients at
high and low risk for stroke or death after carotid artery stenting - CAS. Using a
population of patients at high surgical risk undergoing stenting (the SAPPHIRE
worldwide study), researchers identified variables that were independently
associated with higher risk, including demographic, clinical history, and
lesion anatomy features, with the aim of developing a bedside tool for risk
prediction. "We developed and validated a predictive model and
integer-based tool to predict the occurrence of death or stroke within 30 days
of CAS," Neil J. Wimmer, MD, from the Division of Cardiovascular Medicine,
Brigham and Women’s Hospital, and Harvard Medical School, Boston, Massachusetts,
and colleagues conclude. The tool was validated internally by statistical
methods, but the investigators are also in the process of validating it
externally in a new dataset, told senior author Laura Mauri, MD, also from the
Division of Cardiovascular Medicine, Brigham and Women’s Hospital, and Harvard
Medical School. "That being said, it's pretty robust," she said of
the tool. "It's been constructed in over 10,000 patients and is already in
a form that's easy to use, so we hope it will be able to be used right away by
clinicians to estimate risk in individual patients." Their report was published online November 5 in Stroke to coincide with its
presentation at the American Heart Association Scientific Sessions 2012 in Los
Angeles, California. The SAPPHIRE trial was a randomized comparison of CEA (carotid endarterectomy) vs
carotid angioplasty and stenting in patients deemed at high surgical risk.
However, with only 334 patients, it was not large enough to determine the
features strongly associated with periprocedural risk, the authors write. For
this analysis, they used data from SAPPHIRE, a single-group prospective study
of higher-risk patients undergoing CAS using distal protection. The goal was to
develop and internally validate a model and bedside tool to predict death or
stroke within 30 days of stenting in patients at higher surgical risk by using
variables that could be collected easily during clinical practice, the authors
write. "The prediction model generated here can be used to support
decision-making." Only patients with at least a single anatomic or
comorbid factor associated with elevated surgical risk were included; in all,
10,186 patients were included in the analysis. The overall rate of stroke or
death was 3.6% at 30 days after carotid stenting, which, Dr. Mauri said, is
"interesting, because the patients who were included in the study were
selected for having a high risk for undergoing carotid endarterectomy. And
there are certain consensus opinion variables that surgeons feel increase the
risk of carotid endarterectomy. Well, those variables are different from the
ones that pertain to carotid artery stenting." They found that elevated
age, history of stroke, history of transient ischemic attack (TIA), recent
myocardial infarction (MI), the need for both cardiac surgery and carotid
revascularization, dialysis treatment, the presence of a type 2 or 3 aortic
arch, a right-sided carotid stenosis, a longer carotid plaque, and a severely
tortuous carotid arterial system were all important risk factors for the
development of stroke or death within 30 days of CAS.
·
Increased age
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·
History of stroke
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·
History of TIA presentation
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·
Recent (<4 weeks) MI
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·
Dialysis treatment
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Need for cardiac surgery as
well as carotid revascularization
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·
Right-sided carotid stenosis
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Longer carotid plaque
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·
Type 2 or 3 aortic arch
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·
Tortuous carotid arterial system
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Using
these factors, the researchers developed a model and integer-based risk score
for predicting stroke or death within 30 days. The model was calibrated and
internally validated, using bootstrap resampling. The risk score, included in
the article, assigns points for each risk factor. The sum of the points relates
to the level of risk, ranging from a less than 3% risk with 8 or fewer points
to a greater than 10% risk with 16 or more points. "If you just look at
the table for the risk score, the most powerful predictors obviously are the
ones that give you the most points, and patients who needed to have carotid
surgery together with coronary revascularization were at very high risk;
patients with a recent MI, patients undergoing dialysis, those were really
strong predictors, in addition to patients with advanced age, particularly
those who were over 70 years of age," Dr. Mauri said.
