Identifying Which Patients With Asymptomatic Carotid Stenosis Could Benefit From Intervention

Carotid guidelines recommend carotid endarterectomy (CEA) for patients with 60% to 99% asymptomatic carotid stenosis (ACS) provided the perioperative stroke/death rates are <3%.1,2 Several reports have noted that the average annual risk of ipsilateral/any territory stroke among patients with asymptomatic moderate to severe internal carotid artery stenosis receiving medical therapy (MT) alone has now fallen to ≈1%.3–5 The decreased incidence of stroke has been attributed to modern MT and has made opinion leaders demand a revision of management strategies4 by either refraining from CEA6 or by identifying high-risk patients.7 Such high-risk patients should be offered prophylactic CEA in addition to MT to reduce the risk of a future stroke. It is therefore essential to develop methods to identify these ACS patients at high enough risk to warrant prophylactic intervention.Several methods have been proposed for the identification of ACS patients at high risk for future stroke (Table),6,8–22 namely: (1) the detection of microemboli by transcranial Doppler (TCD), (2) identification of the unstable carotid plaque using ultrasound, (3) reduced cerebral blood flow reserve, (4) intraplaque hemorrhage using magnetic resonance imaging (MRI) scans, (5) silent embolic infarcts on brain computed tomography (CT) or MRI, and (6) progression in the severity of ACS. A discussion of the involved mechanisms and the predictive value of each of these methods is presented.View this table:Table. Suggested Predictors of the Development of Stroke/Transient Ischemic Attack in Asymptomatic Carotid PatientsThe predictive value of microemboli detection on TCD for the identification of ACS patients at high risk for stroke has been validated by 2 independent studies and is further supported by a meta-analysis.6,8–10,23 A small prospective, observational, cohort study failed to verify the association between TCD-detected emboli and …