Carotid Endarterectomy Update

INDEX

• Asymptomatic Carotid Stenosis : detected by cervical (neck) bruit (a sound heard with a stethoscope) or other screening method.
• Symptomatic Carotid Stenosis : stroke, Transient Ischemic Attack/TIA, transient monocular (one eye) blindness
• Return to the MGH Cerebrovascular Homepage for more information about the prevention of stroke by carotid endarterectomy.

A statement from The Joint Section on Cerebrovascular Surgery of The American Association of Neurological Surgeons and the Congress of Neurological Surgeons.

Asymptomatic Carotid Stenosis

Four recent trials concerning carotid endarterectomy have been completed. The first three including, the Carotid Artery Stenosis with Asymptomatic Narrowing Operation Versus Aspirin (CASANOVA) Study, the Mayo Asymptomatic Carotid Endarterectomy Trial (MACE), and the Veterans Administration (VA) Cooperative Trial on Asymptomatic Carotid Stenosis, yielded inconclusive results.

Asymptomatic carotid stenosis >60% medical versus surgical therapy aggregate risk of ipsilateral (same side) stroke.

The largest trial concerning the management of asymptomatic carotid stenosis (ACAS), however, reached a stopping rule, and the data were released to coinvestigators in September of 1994. One thousand six hundred sixty two patients were entered in the ACAS trial at 39 centers. All patients had greater than 60% stenosis of the carotid artery and were randomized to either medical treatment with 325 mg of aspirin daily, or aspirin plus carotid endarterectomy. The primary endpoints of this study were stroke ipsilateral to the carotid stenosis or death within thirty days of randomization. The aggregate risk for the primary outcome in the medical group was 10.6% versus 4.8% in the surgical group. Carotid endarterectomy provided a statistically significant benefit with an absolute risk reduction of 5.8%, and a relative risk reduction of 55% in the risk of the primary endpoint of stroke within five years. The benefit was greater in men, with a 69% relative risk reduction compared to a 16% risk reduction in women. These positive results were dependent on the operation being performed in medical centers where the surgeon had a documented perioperative morbidity and mortality of 3%.

A Multidisciplinary Consensus Statement from the American Heart Association concluded that carotid endarterectomy, performed in medical centers with documented combined perioperative morbidiy and mortality for asymptomatic endarterectomy of less than 3%, in conjunction with aggressive modifiable risk factor management is beneficial for patients who have an asymptomatic stenosis exceeding 60% diameter reduction confirmed by angiography.

Carotid endarterectomy asymptomatic stenosis >60% relative risk reduction

References

1. Guidelines for Carotid Endarterectomy. A Multidisciplinary Consensus Statement for the Ad Hoc Committee, American Heart Association. Stroke 26:188-201, 1995
2. Clinical Advisory: Carotid Endarterectomy for Patients with Asymptomatic Internal Carotid Artery Stenosis. Stroke 25:2523-2524, 1994

Symptomatic Carotid Stenosis

Three trial regarding the role of carotid endarterectomy in the treatment of patients with symptomatic carotid stenosis were generally in concurrence. A European trial of symptomatic patiens (ECST) in all subgroups from 0 - 99% stenosis was paralleled by two trials in North America: The North Amercian Symptomatic Carotid Endarterectomy Trial (NASCET) and the VA Clinical Studies Program 309. The EXST and NASCET trials reported a clear surgical benefit in patients with greater than 70% stenosis. The VA study was stopped after the previous results were released, and the data showed a benefit for greater than 50% stenosis.

Carotid endarterectomy symptomatic stenosis >50% ipsilateral stroke/crescendo TIA (VA CSP 309)

The European study showed no benefit from surgery for stenosis less than 30%, and the NASCET trial is continuing to enter patients with stenosis between 30% to 70%, because the treatment of choice for this group has not been clearly established.

A Multidisciplinary Consensus Statement from the American Heart Association concluded that carotid endarterectomy is of proven benefit for symptomatic patients, including those with single or multiple TIAs or those who have suffered a mild stroke within a 6-month interval, who have stenosis of greater than 70% with a surgical risk of less than 6%1.

Reference

• Guidelines for Carotid Endarterectomy. A Multidisciplinary Consensus Statement from the Ad Hoc Committee, American Heart Association. Stroke 26:188-201, 1995.

Carotid endarterectomy symptomatic stenosis >70% ipsilateral stroke (ECST)

Carotid endarterectomy symptomatic stenosis >70% Ipsilateral stroke (NASCET)