1. < Clinical Trials

JACKSONVILLE, Fla. — A major international study led by Mayo Clinic researchers and funded by the National Institutes of Health found that for people with severe carotid artery narrowing who haven't experienced recent stroke symptoms, a minimally invasive procedure called carotid artery stenting, combined with intensive medical therapy, significantly lowered stroke risk compared with medical therapy alone. Traditional surgery (carotid endarterectomy) did not show the same benefit. The research is published in The New England Journal of Medicine.

The Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis Trial (CREST-2) is the largest study to date comparing current treatment approaches for this condition, caused by plaque buildup in the arteries supplying blood to the brain.

Carotid stenosis can lead to a stroke if plaque breaks off and blocks blood flow. Although surgery and stenting have long been used to open these arteries, newer medications and better risk factor control have raised questions about whether these procedures are still needed for people who don't have symptoms.

"Decades ago, surgery clearly helped prevent strokes in many patients," says Thomas Brott, M.D., a neurologist at Mayo Clinic in Florida and the study's senior author. "But medical therapy has improved so much that we needed to reexamine the balance between benefit and risk for people who have no symptoms."

The CREST-2 program consisted of two parallel, randomized clinical trials conducted at 155 medical centers in five countries, including Australia, Canada, Israel, Spain and the U.S. Each enrolled more than 1,200 adults with severe carotid artery narrowing of 70% or greater who had not had a stroke or transient ischemic attack (ministroke) in the past six months.

In one trial, participants received stenting plus intensive medical therapy or medical therapy alone. In the other, participants received endarterectomy plus medical therapy or medical therapy alone.

All participants received comprehensive medical care, including lifestyle coaching and medication as needed, to manage their blood pressure, low-density lipoprotein (LDL) cholesterol and diabetes, and to help them stop smoking.

Working with investigators from the University of Alabama at Birmingham, researchers analyzed the occurrence of stroke and death within 44 days of stenting or surgery. They also analyzed the occurrence of stroke over four years on the same side of the body as the narrowed artery.

The stenting trial found a significant reduction in stroke: over four years, 2.8% of patients treated with stenting and medical therapy had a stroke compared to 6% of those on medical therapy alone (roughly half the risk of stroke). However, in the endarterectomy trial, the difference in stroke rates (3.7% with surgery vs. 5.3% with medical therapy alone) was not statistically significant. Serious complications were uncommon with either procedure.  

The findings provide clearer guidance for physicians and patients considering a preventive procedure. Dr. Brott emphasizes personalized decision-making.

"For some patients — particularly those with more advanced narrowing or plaque that appears unstable or more likely to cause a blockage — stenting may offer added protection, while for others, medical therapy alone may be enough," he says.

Close follow-up and coordinated care helped all participants achieve and maintain significant improvements in their blood pressure and cholesterol levels.

Researchers will continue to track participants for long-term results. They are also studying whether imaging tools can help identify which patients benefit most from each treatment.

For a full list of authors and disclosures, see the paper.

Related: Mayo Clinic Neurologists Lead International Study to Test Best Approach to Stroke Prevention

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Media contact:

• Julie Ferris-Tillman, Ph.D., Mayo Clinic Communications, newsbureau@mayo.edu

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