Intraoperative Measurement of Internal Carotid Artery Blood Flow Using Transit-Time Flowmetry After Carotid Endarterectomy: Results from 196 Consecutive Cases

Background/Objectives: Carotid endarterectomy (CEA) is a standard surgical treatment for high-grade symptomatic and asymptomatic internal carotid artery (ICA) stenosis. The Transit Time Flowmeter (TTF) provides an easy-to-use tool to quantify intraoperative ICA blood flow in mL/min. This study aimed to (1) describe post-CEA ICA flow quantified with TTF, (2) identify predictors of post-CEA ICA flow, and (3) examine its association with contralateral steno-occlusive disease. Methods: We queried data from our prospective registry of patients who underwent a CEA between January 2019 and July 2024 and had intraoperative registered post-CEA ICA flow measurements using TTF. Preoperative ICA stenosis was graded according to the NASCET criteria. The clinical data was retrospectively collected. Results: Data from 196 CEAs in 190 patients (median age 74 [67–81]; 25% female) were included. Most patients (86%) had a symptomatic ICA stenosis. The median post-CEA ICA flow was 170 mL/min [IQR 140–242; range 40–800]. Post-CEA ICA flow was not associated with age, sex, comorbidities, symptomatic stenosis, left ventricular ejection fraction (LVEF), or ipsilateral stenosis severity but was significantly higher in patients requiring intraluminal shunt placement during CEA (p = 0.010) as well as in those with contralateral steno-occlusive disease (p < 0.001). Conclusions: TTF is a practical intraoperative tool for quantitative flow assessment during CEA. Higher post-CEA ICA flow in patients with an intraoperative shunt placement or with contralateral steno-occlusive disease may reflect a compensatory hyperperfusion, as the ipsilateral ICA serves as a key supplier when collateral pathways are incomplete.