Determining Criteria for Shunt Placement During Carotid Endarterectomy

Abstract

EEG monitoring and carotid back pressure were performed on 100 patients undergoing elective carotid endarterectomy. Shunts were inserted selectively in those patients who showed change in EEG after a trial period of carotid clamping (15%). No patient in the series awoke with a neurologic deficit. Back pressures were significantly lower in the shunted group and these pressures roughly correlated with EEG changes. Only one patient with a back pressure of greater than 40 mmHg had EEG changes and this patient had a recent mild stroke. EEG changes were most frequent in patients with contralateral carotid occlusions and in asymptomatic significant stenoses. EEG is a more discriminating indicator for shunt insertion than back pressure, although a pressure greater than 40 mmHg is safe in patients without recent stroke.

Prospective randomized trial of routine versus selective shunting in carotid endarterectomy based on stump pressure

“…Several authorities have correlated EEG monitoring and stump pressure measurement in patients undergoing general anesthesia and in awake patients to determine the reliability of these methods in detecting cerebral ischemia and selecting shunting. 9,15,16,[35][36][37][38] Selective shunting according to EEG changes is associated with a need for shunting in 15% to 18% of patients. 9, 15 Calligaro and Dougherty 16 reported the correlation of carotid artery stump pressure and neurologic changes during 474 CEAs performed in awake patients and indicated if CEA had been performed under general anesthesia, shunts would have been placed in 29% of patients if a stump pressure of Ͻ50 mm Hg systolic had been used as the threshold for shunting, and about 15% would have been shunted had a stump pressure of Ͻ40 mm Hg systolic been used.…”

“…[9][10][11]14,16,17 Some have suggested a systolic stump pressure of Ͻ50 mm Hg and Ͻ40 mm Hg, and others selected a mean stump pressure of 50, 45, 40, or 25 mm Hg. A few randomized trials have compared routine vs selective shunting during CEA, 8,13,29 but none were based on stump pressure.…”

Wake-Up Test Decrease Shunts Insertion During Carotid Endarterectomy Under General Anesthesia

“…Studies have shown several criteria to determine the need for carotid shunt placement during surgery, which include SP, EEG, TCD, SSEP, and NIRS. [12][13][14][15][16][17][18][19][20][21][22][23] In our cohort, shunts would have been placed in 12.8% of patients using the SPs 40 mm Hg criteria; however, less than half of these (5.8%) actually underwent shunting based on the WUT criteria. Moreover, 20% of patients (4/20) with a normal SPs >40 mm Hg criteria (false negative) required shunting due to neurological change (positive WUT).…”

“…No single method has shown to offer better surgical outcomes to date. [20][21][22] The systolic SP (SPs) criteria is generally used for selective shunting insertion under GA 15,16 when SP <50 mm Hg. This cutoff value, however, includes false-positive and false-negative rates.…”

A Selective Carotid Artery Shunting for Carotid Endarterectomy: Prospective MR DWI Monitoring of Embolization in a Group of 754 Patients

“…Some never use shunts periprocedurally. [6][7][8][9][10][11][12][13][14] So far, no evidence for routine or selective shunting has been presented.…”