Carotid Stenting

Carotid Stenting

Carotid artery stenting (CAS) is an endovascular, catheter-based procedure which unblocks narrowings of the carotid artery lumen to prevent a stroke. Carotid artery stenosis can present with no symptoms (diagnosed incidentally) or with symptoms such as transient ischemic attacks (TIAs) or cerebrovascular accidents (CVAs, strokes). The largest clinical trial to date, CREST, compared stenting to surgery on the collective incidence of any stroke, any heart attack or death. They found that there was no significant differences out to four years of follow-up between surgery and carotid stenting when counting all three, but carotid endarterectomy (CEA) has a higher risk of heart attacks and CAS has a higher risk of minor stroke than open surgery. Overall, younger patients (<70 years old) had better outcomes with stenting than with surgery. Patients had fewer heart attacks with stenting, but they did have more minor strokes. There was no difference between surgery or stenting for major (disabling) strokes.

Prior to this, several European trials have reported results in symptomatic carotid artery stenosis patients comparing surgery and stenting. A major problem with the European trials is they allowed inexperienced operators to place stents, while the surgeons performing CEA were very experienced. The SPACE trial, conducted in Germany, Austria, and Switzerland found no difference in outcomes between surgery and stenting. They also noted that younger (< 67 years old) patients had better outcomes with stenting. They noted that more experienced centers had better results than inexperienced centers.

The EVA-3s trial was stopped early due to an early finding that stenting was too dangerous. The trial was criticized that they used experienced surgeons and inexperienced stent physicians, so that the results may have been affected by the training of operators. Future trials ensured that the endovascular arms had more experienced endovascular operators, as seen in the CREST and SAPPHIRE trial.

An interim report from ICSS demonstrates no overall difference between surgery and stenting for both major strokes and death, but again did show more minor strokes (resolved within 30 days) with stents and open surgery was safer than CAS in the treatment of symptomatic carotid artery disease. A study was carried out in seven of the centers participating in ICSS to assess the incidence of ischemic brain lesions (silent infarcts) detected by diffusion-weighted MRI. They found that 73% of patients undergoing CAS with distal filter protection showed new ischemic lesions after the procedure versus 17% of those undergoing CEA. Again, the CAS operators were less experienced than the CEA operators which may have imbalanced the study.

Recently physicians have questioned the ethics and validity of European trials comparing a mature carotid surgical procedure to carotid stenting performed by inexperienced physicians. In CREST, the largest trial comparing stenting to surgery in over 2,500 patients, physicians were required to demonstrate their expertise before being allowed to enroll patients in the trial. This trial showed no difference between carotid stenting and carotid surgery in average risk patients.

Most recently, a broad consensus of experts released a guideline document suggesting that in most cases, carotid stenting may be considered an alternative therapy to surgery.