Carotid angioplasty with stent (CAS) placement is an emerging alternative to carotid endarterectomy for the treatment of patients with carotid artery occlusive disease. Mayo Clinic neuroradiologists began using it in 1996 for patients at high risk for surgery.
"The Cerebrovascular Clinic in the Department of Neurology has a multidisciplinary CAS placement protocol in which a vascular neurologist, an interventionalist, and a neurosurgeon meet with the patient to help clarify the best treatment approach. Cardiology colleagues may also be involved if the patient has cardiac symptoms. This collaboration is not uncommon, since so many patients with carotid occlusive disease also have coronary artery occlusive disease," says neurologist Robert D. Brown Jr, M.D.
Adds Harry Cloft, M.D., Ph.D., a neuroradiologist, "The protocol has been highly successful in allowing us to select patients carefully and appropriately as we move forward with this emerging technology."
Candidates for CAS placement are patients with a severe narrowing of the carotid artery who have had symptoms such as transient ischemic attacks or cerebral infarction, and also selected patients who have severe narrowing of the carotid artery without symptoms, according to Dr. Brown and neurosurgeon Giuseppe Lanzino, M.D.
Most patients arrive at the Cerebrovascular Clinic at Mayo Clinic in Rochester, Minnesota, after carotid ultrasonography, magnetic resonance angiography, or computed tomographic angiography has shown narrowing of the carotid artery. After thoroughly examining the patient, the multidisciplinary neuroscience team members decide whether CAS placement is the appropriate treatment.
If it is, the patient proceeds to the interventional neuroradiology suite in Saint Marys Hospital for further evaluation. The patient is sedated but awake. A small plastic catheter is inserted in a groin artery and tracked through the aorta to the carotid arteries. Next, contrast material is injected to delineate the anatomy. If the angiogram confirms severe narrowing that could be best treated with CAS placement, the procedure begins.
Aftercare involves taking clopidogrel and aspirin daily for one month to prevent blood clots from forming at the stent site and then aspirin alone indefinitely thereafter. Mayo Clinic specialists follow each patient long term, both to assess durability of the stent and to determine whether narrowing recurs. Follow-up includes annual carotid ultrasonography that begins several months after the procedure.
The concept of CAS placement is a logical extension of the balloon stenting used for coronary artery disease. Initially, in the early 1990s, CAS placement was performed on patients who were at high risk for conventional surgery. The outcomes of these early cases were excellent, and the risk of stroke and death was extremely low. Because these measures of success were so similar to those of the standard treatment, carotid endarterectomy, the use of CAS placement was cautiously and carefully expanded.
Since then, Mayo Clinic experience with CAS placement suggests that, when performed by an experienced, multispecialty team on carefully selected patients, the procedure is approximately equal to carotid endarterectomy in terms of effectiveness, risks, and complications.
The National Institutes of Health selected Mayo Clinic to participate with other U.S. medical centers in the formal evaluation of CAS placement in the Carotid Revascularization Endarterectomy versus Stent Trial (CREST). The goal of CREST is to determine how CAS placement compares with carotid endarterectomy, the standard treatment for carotid artery stenosis.
A key question is whether the risk of recurrent narrowing after CAS placement is as low as the extremely low risk of recurrent narrowing after carotid endarterectomy. CREST will also evaluate the comparative risks of stroke associated with CAS placement and carotid endarterectomy. Because CAS placement requires the interventionalist to work within the artery, the possibility exists for stroke during the procedure. Carotid endarterectomy, when performed by an experienced neurosurgeon or vascular surgeon, also carries the risk of stroke. The goal of the CREST protocols is to determine these issues conclusively.
CREST completed patient recruitment in the summer of 2008, and the final results will be available in the near future.
Mayo Clinic's Cerebrovascular Clinic is a full-time clinic, providing consultations for patients with carotid stenosis and all other types of cerebrovascular disorders. To refer a patient for evaluation, call the Cerebrovascular Clinic at 507-284-1588.