Intraoperative duplex scanning for carotid endarterectomy

Objectives: To evaluate the results of intraoperative duplex scans during carotid endarterectomy. Design: Retrospective case review. Materials: One-hundred consecutive intraoperative carotid duplex scans performed during carotid endarterectomy between July 1993 and December 1995 at a university teaching hospital. Methods: Abnormalities of the B-mode image and/or the Doppler flow analysis were classified. The results of intraoperative carotid duplex scans (ICDS) were related to the events of the intraoperative course, perioperative neurologic morbidity and mortality, and to residual carotid stenosis. Results: Abnormalities of the ICDS were demonstrated in 13 cases (13%). Abnormalities were classified into four types: I, internal carotid artery spasm (n=9); II, high distal resistance flow (n=2); III, high grade residual stenosis (n=1); IV, intraluminal thrombosis (n=1). Immediate intraoperative exploration and revision of the endarterectomy was performed based on the ICDS in two cases (type III and IV) and the findings of ICDS were confirmed. The other II cases with abnormal ICDS (types I, II) were not revised and duplex scans done I month postoperatively (available in 10 cases) showed normal carotid artery flow. Intraoperative angiography was performed selectively in five cases and confirmed the results of ICDS. Reversible abnormalities of the ICDS were not associated with perioperative morbidity or residual carotid stenosis. Conclusions: Intraoperative carotid duplex scanning can be used to assess the immediate technical adequacy of carotid endarterectomy. B-mode image and Doppler flow abnormalities which are reversible can be distinguished from those which require immediate revision.