Correlation of Carotid Stump Pressure During Carotid Endarterectomy and the Contralateral Carotid/Cerebral Collateral Flow: Results from a Randomized Trial

Abstract

The optimal method for predicting when carotid shunting during carotid endarterectomy (CEA) is unnecessary is controversial. This study analyzed the correlation of carotid stump pressure (CSP) and the status of contralateral carotid/cerebral collaterals and determined whether preoperative duplex ultrasound (DUS)/cerebral angiography (angio) can predict when CEA can be done without shunting. The study randomized 98 patients into routine shunting and 102 into selective shunting if systolic CSP during CEA was <40 mm Hg. All patients had preoperative carotid DUS and 87 had angios, which were evaluated for the presence of collateral flow from the contralateral carotid (CC) or posterior circulation through the anterior and/or posterior communicating arteries. The perioperative stroke rate was 1.5% in the whole group. There was no correlation between preoperative symptoms and the status of the CC (normal, stenosed, or occluded, P = .1898). The mean CSP was inversely related to the severity of CC: 60, 57, 55, 56, and 38 mm Hg for normal, <50%, 50-69%, 70-99% stenosis, and occluded arteries, respectively (P = .005). There was a direct relation between the number of patients with <40 mm Hg CSP (shunted group) and severity of CC stenosis: 6 of 62 (10%), for normal carotid, 7 of 43 (16%) for < 50% (OR, 1.82), 12 of 69 (17%) for 50%-69% stenosis (OR, 1.97), 3 of 10 (30%) for 70%-99% (OR, 4; CI, .81-19.68), and 9 of 13 (70%) for occlusion (OR, 21; CI, 4.98-89.32; P < .0001). None of the patients (0/56) with normal to <70% CC stenosis with cross-filling had CSP of <40 mm Hg (no shunting was necessary). In contrast, 9 of 17 patients (53%) with <70% CC stenosis and no cross-filling had CSP of <40 mm Hg (P < .0001). Meanwhile, 6 of 7 (86%) with ≥70% CC stenosis and cross-filling vs 2 of 7 (29%) with ≥70% CC stenosis and no cross-filling had CSP of >40 mm Hg (P = .1026). Overall, 62 of 63 patients (98%) with cross-filling vs 10 of 24 (42%) without cross-filling had a ≥40 CSP (P < .0001). There was inverse correlation between CSP and severity of CC stenosis, and patients with severe CC stenosis/occlusion were more likely to be shunted. The presence of cross-filling with normal to <70% CC stenosis was associated with CSP of ≥40 mm Hg in 100% of patients, who would not be shunted in our series.