from The Joint Section on Cerebrovascular Surgery of The American Association
of Neurological Surgeons and the Congress of Neurological Surgeons.
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
- Guidelines for Carotid Endarterectomy.
A Multidisciplinary Consensus Statement for the Ad Hoc Committee, American Heart
Association. Stroke 26:188-201, 1995
Advisory: Carotid Endarterectomy for Patients with Asymptomatic Internal Carotid
Artery Stenosis. Stroke 25:2523-2524, 1994
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)
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.
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.
- 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)