One of the largest randomized stroke prevention trials, the Carotid Revascularization Endarterectomy vs. Stenting Trial (CREST) was conducted at 117 centers in the United States and Canada over nine years, including Emory Heart & Vascular Center.
“This landmark study shows that surgery and stenting are equally safe and effective for people with carotid artery disease,” says Elliot Chaikof, MD, PhD, chief of the Division of Vascular Surgery and Endovascular Therapy, Emory University.
“This knowledge gives physicians more options to customize treatment for patients at risk for stroke,” adds Chaikof, lead investigator for CREST at Emory.
The clinical trial included 2,502 participants. Carotid endarterectomy (CEA), a surgical procedure to clear blocked blood flow and considered the gold standard prevention treatment, was compared to carotid artery stenting (CAS), a newer and less invasive procedure that involves threading a stent and expanding a small protective device in the artery to widen the blocked area and capture any dislodged plaque.
CREST compared the safety and effectiveness of CEA and CAS in patients with or without a previous stroke. The study was funded by the National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institutes of Health.
The overall safety and efficacy of the two procedures was largely the same with equal benefits for both men and for women, and for patients who had previously had a stroke and for those who had not. However, when the investigators looked at the numbers of heart attacks and strokes, they found differences.
The study found that there were more heart attacks in the surgical group – 2.3 percent compared to 1.1 percent in the stenting group. There were more strokes in the stenting group, 4.1 percent versus 2.3 percent for the surgical group in the weeks following the procedure.
The study also found that the age of the patient made a difference. At approximately age 69 and younger, stenting results were slightly better, with a larger benefit for stenting, the younger the age of the patient. Conversely, for patients older than 70, surgical results were slightly superior to stenting, with larger benefits for surgery, the older the age of the patient. Results for all men and women were excellent, according to study investigators.
Stroke, the third leading cause of death in the United States, is caused by an interruption in blood flow to the brain by a clot or bleeding. The carotid arteries on each side of the neck are the major source of blood flow to the brain. The buildup of cholesterol in the wall of the carotid artery, called atherosclerotic plaque, is one cause of stroke. Because people with carotid atherosclerosis also usually have atherosclerosis in the coronary arteries that supply the heart, the CREST trial tracked the rate of heart attacks, in addition to stroke and death.
In CREST, approximately half the patients had recent symptoms due to carotid disease such as a minor stroke, or a transient ischemic attack (TIA), indicating a high risk for future stroke. The other half had no symptoms, but were found to have narrowing of the carotid artery on one of a variety of tests assessing carotid narrowing and plaque. Such patients, termed asymptomatic, are at much lower risk of stroke than those with symptoms.
One of the strengths of the study, according to investigators, is that CREST was conducted in a variety of real world settings, including large and small public and private hospitals. Physicians had to demonstrate a high degree of proficiency and safety in order to participate in the trial. The study found no significant differences in the outcomes, no matter what type of medical specialist performed the stenting procedure, including cardiologists, neuroradiologists, interventional radiologists, vascular surgeons and neurosurgeons.
The researchers point out that the rate of stroke and death in the surgical group was the lowest ever reported in a large stroke prevention trial.
As a result, the pivotal differences were the lower rate of stroke following surgery and the lower rate of heart attack following stenting, according to the investigators. A year after the procedure, the patients who had suffered a stroke reported that the effects of the stroke had a greater impact on their quality of life than was reported by those patients who had suffered a heart attack.
The CREST investigators concluded that while CEA has a proven record and long term durability, both CAS and CEA are safe and useful tools in the right setting for stroke prevention, and technology continues to improve each procedure.