Asymptomatic carotid stenosis benefit

How centers and clinicians were selected to participate in trials is seldom reported, but it can also have important implications for external validity. For example, the Asymptomatic Carotid Atherosclerosis Study (ACAS) trial of endarterectomy for asymptomatic carotid stenosis only accepted surgeons with an excellent safety record, rejecting 40% of applicants initially, and subsequently barring from further participation those who had adverse operative outcomes in the trial. The benefit from surgery in the trial was a result in major... 

Who benefits most from surgery for asymptomatic carotid stenosis ... 

There are data to suggest that patients with asymptomatic carotid artery stenosis of 60% or more benefit from carotid endarterectomy if it is performed by a qualified surgeon with low complication rates (less than 3%). At this time, there is considerable controversy over how this information can be applied to clinical practice. A current review recommends considering carotid endarterectomy in patients with carotid artery stenosis... 

Cerebral microembolic signals are detected by tran-scranial Doppler in 1% to 23% of patients with asymptomatic CAS (36-38). The prevalence of cerebral microembolic signals in patients with asymptomatic CAS varies with the severity of the carotid stenosis, the morphology of the carotid plaque, and the frequency and duration of transcranial Doppler monitoring. The presence of cerebral microembolic signals in patients with asymptomatic CAS has been associated with a risk of stroke increased four to five times (38). However, the clinical utility of this technique to discriminate among patients who will benefit from carotid revascularization versus those who would not awaits confirmation in prospective trials. 

MRA of neck vessels is important in stroke management because extracranial atherosclerosis causes an estimated 20-30% of strokes. The NASCET trial demonstrated that carotid endarterectomy improves survival in symptomatic patients with carotid stenosis of 70-99% [35]. The Asymptomatic Carotid Atherosclerosis Study also suggested that asymptomatic patients with a stenosis of 60% could benefit from endarterectomy [36]. Since then, multiple studies have evaluated the ability of contrast-enhanced and noncontrast MRA to distinguish between nonsurgical (<70%) and surgical stenoses (70-99%). 

Most experts agree that certain patients with asymptomatic CAS are at high risk for stroke and may derive significant benefit from carotid revascularization. Identification of those patients, however, has been elusive in clinical trials. Risk stratification of patients with asymptomatic CAS is particularly important among patients with 60% to 79% stenosis, in whom the appropriate management is more uncertain. Identifying high-risk patients will certainly lead to better resource utilization for both medical and revascularization therapies for patients with asymptomatic CAS. 

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