Preoperative Carotid Duplex Findings Predict Carotid Stump Pressures During Endarterectomy in Symptomatic But Not Asymptomatic Patients

Abstract

Carotid stump pressure (CSP) is frequently measured to determine the need for shunt use during carotid endarterectomy (CEA). We hypothesized that the preoperative carotid duplex examination correlates with preoperative symptoms and intraoperative CSP. Patients undergoing CEA over a 7-year period were identified from our vascular registry. CEA was performed with selective shunting on the basis of intraoperative CSP <30 mm Hg regardless of symptoms or contralateral internal carotid artery (ICA) stenosis. The preoperative duplex was categorized by ipsilateral and contralateral ICA diameter-reduction stenosis (<15%, 15-45%, 45-70%, 70-99% [severe] and occluded), and the direction of vertebral artery flow. The relationships among preoperative duplex findings, symptom status, and CSP were evaluated using unpaired t-test and Chi-square analysis. A total of 303 CEAs were performed. Stump pressures were documented in 284 patients, which comprised the study population. Asymptomatic severe stenosis was the indication for CEA in 179 cases (59.1%). Symptomatic patients (Sx) had significantly lower stump pressures than asymptomatic (ASx) patients (40.72 ± 16.27 vs. 45.8 ± 17.64 mm Hg, p = 0.0167). Fifty-seven patients (19%) had contralateral severe ICA stenosis or occlusion. Contralateral ICA stenosis or occlusion had significantly lower CSP than those with lesser degrees of stenosis (39.24 ± 15 vs. 44.82 ± 17.62 mm Hg, p = 0.0267). Contralateral ICA severe stenosis or occlusion correlated with lower CSP in Sx patients (32.05 ± 8.24 vs. 42.92 ± 16.95 mm Hg, p = 0.038) but not in ASx patients (43.2 ± 16 vs. 46.29 ± 17.5 mm Hg, p = 0.39). CSP was <30 mm Hg in 63% of Sx patients and 24% of ASx patients (p = 0.012). Overall shunt usage was 84/2,842 (9.5%). Perioperative stroke and death rate was 2.7%. Perioperative stroke did not correlate with the presence of contralateral occlusion, or severity of contralateral stenosis. Symptomatic patients undergoing CEA have lower stump pressures than ASx patients overall and also in the presence of contralateral disease. The incidence of perioperative stroke was not predicted by severity of contralateral disease. A strategy of selective shunting seems appropriate even in Sx patients with contralateral severe stenosis or occlusion. Although a high-risk cohort for perioperative neurologic events exists and may include those with symptomatic disease and contralateral severe stenosis or occlusion, further study is warranted to define the patients who will clinically benefit from shunt placement.