Selective shunt during carotid endarterectomy using routine awake test with respect to a lower shunt rate

Abstract

Purpose: To evaluate shunt rate and discuss the resultsrelated to selective shunt placement during carotid endarterectomy (CEA) using routine awake test.

Methods: Patients with CEA from 2007 to 2011 were retrospectively reviewed from prospectively collected data. The need for shunt placement was determined by the awake test, based on the alteration in the neurologic examination. We collected data by using the clinical records and imaging studies, and investigated factors related to selective shunt such as collateral circulation and contralateral internal carotid artery (ICA) stenosis.

Results: There were 45 CEAs under regional anesthesia with the awake test in 44 patients. The mean age was 61.8 ± 7.1 years old. There were 82.2% (37/45) of males, and 68.9% (31/45) of symptomatic patients. Selective shunt placement had been performed in only two (4.4%) patients. Among them fewer cases (4%) had severe (stenosis >70%) contralateral ICA lesions, and more cases (91%) of complete morphology of the anterior or posterior circulation in the circle of Willis. There was no perioperative stroke, myocardial infarctionor death, and asymptomatic new brain lesions were detected in 4 patients (9%), including 2 cases of selective shunt placement.

Conclusion: CEA under routine awake test could besafe and feasible method with low shunt placement rate in selected patients.

Keywords: Brain ischemia; Carotid endarterectomy; Intraoperative monitoring; Prevention.

Fig. 1

Categories of contralateral internal carotid artery (ICA) stenosis are shown in the computed tomography angiography. Severe stenosis (>70%) was in the ipsilateral ICA lesions (arrow of A, B and C). Severe stenosis (>70%) (arrowhead of A), moderate stenosis (50% to 69%) (arrowhead of B) and mild stenosis (<50%) (arrowhead of C) were in the contralateral ICA lesions.

Fig. 2

Morphologic findings of the circle of Willis in the 3-dimentional reconstruction of computed tomography angiography show normal (diameter, ≥0.8 mm) (arrow of A), hypoplastic (diameter, <0.8 mm) (arrow of B) and absent (arrow of C) anterior circulation and normal (arrowhead of D), hypoplastic (arrowhead of E) and absent (arrowhead of F) posterior circulation.