Which patients benefit from carotid stenting? What recent trials show

WHO SHOULD NOT UNDERGO CAROTID ENDARTERECTOMY?

From these studies, we can conclude that patients with symptomatic carotid stenosis of 50% or greater and patients with asymptomatic stenosis of 60% or greater benefit from carotid endarterectomy, but only if the perioperative rate of death and other serious complications is less than 3%.⁷

What are the risk factors for complications during this surgery? In 2006, Cremonesi et al,⁹ in a consensus paper, defined patients as being at high risk if they had any of the following:

• Contralateral laryngeal nerve palsy
• Radiation therapy to the neck
• Previous carotid endarterectomy with recurrent stenosis
• Lesions high in the cervical internal carotid artery or below the clavicle in the common carotid artery
• Severe tandem lesions
• Age greater than 80 years
• Severe pulmonary disease
• Congestive heart failure (New York Heart
• Association class 3 or 4) or known severe left ventricular dysfunction
• Open heart surgery needed within 6 weeks
• Myocardial infarction within the past 4 weeks
• Unstable angina
• Contralateral carotid occlusion.

Could endovascular treatment be the answer for these patients at high risk who should not undergo carotid endarterectomy? Indeed, the procedure is being studied extensively and performed more frequently. We summarize the major studies below.

STUDIES OF CAROTID STENTING VS ENDARTERECTOMY

The Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS)

This study, published in 2001,¹⁰ was the first randomized, multicenter trial to compare the risks and benefits of endovascular treatment (angioplasty with or without stenting) of carotid and vertebral artery stenosis with those of conventional surgery.

To be included, patients had to have carotid artery stenosis (symptomatic or asymptomatic) that was suitable for either carotid endarterectomy or endovascular treatment. Patients were not grouped on the basis of the severity of their stenosis, but the mean stenosis in randomized patients was 86%.

A total of 504 patients were enrolled, of whom 251 were randomized to undergo endovascular treatment. Most patients in this group underwent angioplasty alone, but 26% also received stents because of suboptimal vessel dilatation or at the discretion of the intervening physician.

The primary end point was any disabling stroke or death. Secondary end points were any ipsilateral stroke lasting longer than 7 days and the combination of death or disabling ipsilateral stroke.

The results showed no significant difference between endovascular treatment and surgery in any of these end points at 3 years. However, the overall rates of procedural stroke and death were nearly double those seen in NASCET and ECST. The investigators could not determine the reason for this higher risk, but they hypothesized that CAVATAS included patients at higher risk.

The restenosis rate was higher in the endovascular therapy group (14%) than in the surgery group (4%; P < .001). On the other hand, the surgery group had a higher rate of minor complications, including cranial nerve palsies and neck hematomas.

Carotid Revascularization With Endarterectomy or Stenting Systems (CARESS)

This prospective, multicenter, phase 2 trial, published in 2003, compared the outcomes of standard carotid endarterectomy vs carotid artery stenting using distal embolic protection devices.¹¹ All the patients in this study had at least 50% symptomatic stenosis or 75% asymptomatic stenosis.

Results. At 30 days, 7 (2.4%) of 254 patients in the endarterectomy group had had strokes, and one of the 7 patients with stroke died, so the combined rate of stroke or death (the primary end point) was 2.4%. In the stenting group, 3 (2.1%) of 143 patients had strokes and no patients died. Overall, there was no significant difference in the composite of death, stroke, or myocardial infarction (the secondary end point): 3% for carotid endarterectomy and 2% for stenting patients.

The Stenting and Angioplasty With Protection in Patients at High Risk for Endarterectomy (SAPPHIRE) trial

In this trial,¹² published in 2004, patients had to have either symptomatic carotid disease with 50% stenosis or greater or asymptomatic stenosis of 80% or greater, determined by ultrasonography. Further, all patients had to have at least one comorbid condition that increased their perioperative risk. Up until this point, no trial had strictly defined patients at increased risk for complications after carotid endarterectomy and assessed subsequent outcomes. The risk factors included severe cardiac or pulmonary disease, age greater than 80, postendarterectomy carotid stenosis, previous neck surgery, previous neck radiation, contralateral recurrent laryngeal nerve palsy, and contralateral carotid occlusion.

Patients were randomized to undergo carotid artery stenting with distal protection or carotid endarterectomy.

The primary end points of this study were the cumulative incidence of major cardiovascular events at 1 year; death, stroke, or myocardial infarction within 30 days of intervention; and ipsilateral stroke between 31 days and 1 year. Secondary outcomes measured were the rates of target-vessel recanalization at 1 year, cranial nerve palsy, and surgical site complications.

Results. The rate of stroke or death was similar in both groups. The stenting group had fewer adverse cardiac events (mainly non-Q-wave myocardial infarction) than the surgery group. At 1 year the rate of major ipsilateral stroke was 3.3% in the endarterectomy group vs 0% in the stenting group (the difference was not significant), and the cardiovascular event rates continued to be higher in the endarterectomy group.

The investigators noted that myocardial infarction was included as a primary end point because patients with atherosclerotic vascular disease who undergo either stenting or endarterectomy are at a substantial risk of myocardial infarction, and a Q-wave or a non-Q-wave myocardial infarction in the perioperative period increases the risk of future complications and death. A perioperative non-Q-wave infarction increases the risk of death by a factor of 6 and increases the risk of myocardial infarction by a factor of 27 in the subsequent 6 months.

Overall, this study presents evidence that stenting, using distal embolic protection devices, is not inferior to endarterectomy and has fewer cardiovascular complications in patients who have at least one risk factor.