UPMC Study Shows Protected Carotid Stenting may be Good Alternative for High Risk Patients with Carotid Stenosis
PITTSBURGH, April 11, 2003 In high-risk patients with carotid stenosis, placement of a stent with an umbrella-like filter to open the carotid artery may be a safer alternative to endarterectomy surgery, according to a study presented by a University of Pittsburgh Medical Center (UPMC) physician, at the recent meeting of the American College of Cardiology.
Our study found that using a stent with a filter resulted in an almost 50 percent reduction in stroke in high-risk patients, when compared to endarterectomy surgery, said study coordinator Mark H. Wholey, M.D., of the University of Pittsburgh Medical Center. This study represents a nationally growing trend toward a less invasive, less-expensive procedure than conventional endarterectomy surgery, which entails anesthesia, a longer hospital stay and 5 to 9 percent incidence of cranial nerve palsy, and which is basically a more expensive procedure.
The overall stroke rate after 30 days was only 5.3 percent. The 30-day total major adverse event rate, defined as all-cause stroke, death and myocardial infarction, was 7.8 percent. Most of the strokes were minor and the patients recovered to normal baseline within 30 days. Only 1.4 percent of the patients had major disabling stroke, Dr. Wholey said.
The aim of the multi-center clinical trial was to assess the safety and efficacy of the Acculink carotid stent system and filter device in the treatment of high-risk surgical patients and non-surgical patients with carotid stenosis.
Carotid arteries supply blood to the brain. When they become narrowed by plaque, blood flow to the brain is reduced, which increases the risk of stroke. A surgical procedure called endarterectomy is performed to remove the blockage and re-open the arteries to increase blood flow to the brain.
In the stent procedure, a small flexible catheter with a metallic stent positioned at the end is placed in the narrowed region of the carotid artery. The stent, when deployed, expands and compresses the plaque against the blood vessel wall, thereby enlarging the opening in the carotid artery and maintaining blood flow to the brain. When the catheter is removed, the stent remains in place as a fixed scaffold to keep the artery open. During this study, a filter device was inserted between the stent and the brain to catch particles and debris from the clot and prevent them from flowing into the brain. In the study, debris was present in 50 percent of the filter baskets that were evaluated microscopically.
In the study, called the ARCHeR (Acculink for Revascularization for Carotids in High Risk Patients) trial, all of the participants had at least one risk factor that made them poor surgical candidates and approximately 45 percent of the patients had two or more of these risk factors. A significant number of patients had prior endarterectomy and recurrent stenosis following the surgery. Many patients had the opposite carotid artery occluded and totally blocked, and the lesion site also had a very high grade narrowing of 80 percent or greater.
The mean age of the 437 study participants was 69 years. High-risk characteristics of the patients included unstable angina (26 percent), diabetes (39 percent), hypertension (83 percent) and high cholesterol (68 percent). Of the participants, 28 percent had a previous stroke and 28 percent had a heart ejection fraction of less than 30 percent. All others had renal failure, advanced chronic lung disease and prior heart surgery. Patients were assessed by an independent neurologist prior to the study and during follow-up.
We hope the results of this study will establish less-invasive carotid stenting as an important therapy for this large group of high risk patients suffering from carotid artery disease who are not candidates for standard carotid surgery, said Dr. Wholey.
Dr. Wholey is chairman of the Pittsburgh Vascular Institute at UPMC Shadyside and a principal investigator for the ARCHeR trial. He reported these results at the recent American College of Cardiology meeting in Chicago, March 30, 2003.
The study was sponsored by Advanced Cardiovascular Systems Inc., a subsidiary of Guidant Corporation.