SAN ANTONIO—Carotid stenting and endarterectomy are equally effective procedures for treatment of carotid stenosis, according to preliminary results of the Carotid Revascularization Endarterectomy versus Stenting Trial (CREST) presented at the 2010 International Stroke Conference. Overall, the two procedures were statistically even regarding the primary end point of any stroke, myocardial infarction, or death within 30 days, or ipsilateral stroke in up to four years of follow-up (6.8% for surgery vs 7.2% for stenting). However, researchers found that patients older than 70 fared better with carotid endarterectomy, while younger patients had better outcomes with carotid stenting, with a greater difference found between the two procedures as the age gap widened.
“We now have two excellent treatment options to offer patients,” coauthor Wayne M. Clark, MD, told Neurology Reviews. “Both procedures had low peri-operative complication rates and excellent protocol durability. This has the potential to change the way many patients with carotid artery stenosis are treated.” Dr. Clark is a Professor of Neurology at the Oregon Health and Science University in Portland.
A Decade of Data
CREST is a decade-long, prospective, randomized controlled multicenter trial of 1,321 symptomatic and 1,181 asymptomatic subjects (35% female; 93% minorities) from 117 sites in the US and Canada. The study was preceded by a rigorous credentialing lead-in phase to train and evaluate interventionalists, which involved 1,565 patients not included in the CREST results.
Subject eligibility criteria included conventional-risk patients with symptomatic carotid stenosis, of at least 50% identified by angiography, at least 70% by ultrasound, or greater than 70% by CTA/MRA if ultrasound was between 50% and 69%. Asymptomatic eligibility criteria included carotid stenosis of at least 60% identified by angiography, at least 70% by ultrasound, or greater than 80% by CTA/MRA if ultrasound was between 50% and 69%. Exclusion criteria included unstable angina, a myocardial infarction within the previous 30 days, chronic atrial fibrillation, or an evolving stroke or major stroke likely to confound study end points.
Stroke and Myocardial Infarction
For the end point of stroke during the peri-procedural period, rates in the stenting group were significantly higher than in the surgical group (4.1% vs 2.3%). “This included all magnitudes of strokes—small, medium, and large,” noted Dr. Clark. “However, when you look at just major strokes, there was no difference between the two groups, and [the rate] was fortunately very low.”
Results were different between the two groups regarding myocardial infarction, however. “Heart attack rates were 1.1% in stenting versus 2.3% in surgery, and again, this was highly significant,” Dr. Clark said. “So you have more strokes with stenting and more myocardial infarctions with surgery. Overall, it was a balance with no significant difference.”
For the secondary end point of peri-procedural complication rates within the first 30 days of the procedure, the researchers reported no significant difference between the two groups (carotid endarterectomy, 4.5%; stenting, 5.2%). Peri-procedural cranial nerve palsy showed a much higher rate for surgery than for stenting (carotid endarterectomy, 4.7%; stenting, 0.3%). Rates of a secondary event in the follow-up period (mean 2.5 years) were also similar, with 2.4% for surgery and 2% for stenting.”
The Age Difference
The investigators observed no difference in results between symptomatic and asymptomatic patients, or between males and females. However, there was a significant difference in treatment by age interaction.
“When you get to be approximately age 70, the patients younger than 70 have a small benefit in favor of stenting,” Dr. Clark pointed out. “This relative benefit increased the younger the patient, and conversely over age 70, there was a small benefit in favor of surgery. This relative benefit also increased as patients were older.”
Prior to the study, the researchers anticipated that the less invasive stenting would offer better outcomes than surgery in older patients. However, because atherosclerosis is a systemic disease involving arteries throughout the body, surgery offers precise access to the narrowed artery, whereas implanting a stent requires weaving a catheter through the groin, up to the aortic arch, and into the common carotid artery.
“Stenting involves navigating through a much longer route of the atherosclerotic arteries compared to surgery, with twists and turns that become a little bit more pronounced as we become older,” explained study coauthor Thomas G. Brott, MD, of the Department of Neurology at the Mayo Clinic in Jacksonville, Florida. “So, in retrospect, we think this has something to do with this differential age effect.”
Competing Studies and Results
The evening before the press conference announcing the CREST results, the Lancet published online findings from the International Carotid Stenting Study (ICSS), which found that surgery was superior to stenting (see sidebar).