Abstract WP267: The Impact of Anesthetic Agents on Regional Cerebral Blood Flow During Carotid Artery Clamping in Patients With Debranching Thoracic Endovascular Aortic Repair and Carotid Endarterectomy

Background: Carotid endarterectomy (CEA) and debranching thoracic endovascular aortic repair (debranching TEVAR) would lead to the reduction of cerebral blood flow (CBF) during carotid artery clamping. Intravenous anesthetics decrease CBF more than volatile anesthetics and may exacerbate cerebral hypoperfusion during carotid artery clamping. We have developed an innovative quantitative measure of regional cerebral blood flow (rCBF) that can be performed at the bedside using near-infrared spectroscopy (NIRS). Using this technique, we measured rCBF during CEA and TEVAR to determine the optimal anesthetic for carotid artery clamping. Methods: Patients undergoing debranching TEVAR and CEA were enrolled. We used NIRS and intravenous injection of Indocyanine green (ICG) to measure rCBF before carotid artery clamping, 10 minutes after clamping, and after de-clamping. The rCBF was calculated by Fick’s principle, using the maximum gradient model that combines the peak values and change in arterial blood concentration of ICG in the brain tissue. We evaluated the effects of each anesthetic (intravenous and volatile) on the rCBF of the cross-clamp side of the carotid artery. Results: The results of the intermediate analysis are shown below. Thirty-two patients who underwent debranching TEVAR and twenty-six who underwent CEA were enrolled. In patients who underwent debranching TEVAR, the rCBF increased from 48.4 to 53.5 ml/min/100g in patients anesthetized with volatile anesthetics and decreased from 55.1 to 32.8 ml/min/100g in patients anesthetized with intravenous anesthetics, as shown in the Figure. There was a significant difference between both anesthetics (p=0.034) but no significant difference between both anesthetics with CEA (p=0.93). Conclusion: In patients undergoing debranching TEVAR, volatile anesthetics may be preferable to intravenous anesthetics during carotid clamping.