ABSTRACT NUMBER: ESOC2026YS219 HEMODYNAMIC AND COGNITIVE OUTCOMES AFTER STA–MCA BYPASS IN CHRONIC INTERNAL CAROTID ARTERY OCCLUSION: A PROSPECTIVE STUDY

Abstract Background and aims Patients with chronic internal carotid artery occlusion and cerebral hypoperfusion remain at high risk of recurrent ischemic events despite optimal medical therapy. Although extracranial–intracranial bypass is controversial, selected patients with hemodynamic compromise may benefit from surgical revascularization. This study evaluated hemodynamic, neurological, and cognitive outcomes after superficial temporal artery–to–middle cerebral artery bypass using a multimodal assessment. Methods This prospective single-center study included patients with chronic ICA occlusion and arterial spin labeling (ASL) MRI–confirmed cerebral hypoperfusion who underwent direct STA–MCA bypass. Pre- and postoperative evaluation included computed tomography angiography, digital subtraction angiography, ASL perfusion MRI, and standardized neurological and neuropsychological testing. Donor artery diameters, cerebral blood flow (CBF), neurological status, cognitive performance, and perioperative complications were analyzed. Results Eleven patients underwent STA–MCA bypass. The donor artery was the frontal STA branch in two cases and the parietal branch in nine; the recipient artery was the MCA M3 segment in two cases and M4 in nine. Bypass patency was confirmed by CTA in all patients. One patient developed a transient postoperative psychoorganic syndrome. Postoperative angiography demonstrated significant enlargement of the STA and its branches, with the greatest increase observed in the STA trunk. ASL perfusion MRI revealed a significant increase in CBF across all evaluated regions, with a mean increase of 31.3 ml/100 g/min. STA–MCA bypass resulted in improved cerebral perfusion, high bypass patency, and low perioperative morbidity. Combined ASL perfusion MRI and angiographic analysis may aid individualized surgical decision-making in chronic ICA occlusion. Conflict of interest Ainur Turzhanova: nothing to disclose. Chingiz Nurimanov: nothing to disclose. Iroda Mammadinova: nothing to disclose. Karashash Menlibayeva: nothing to disclose. Daultai Batyrkhanov: nothing to disclose. Assel Kabykenova: nothing to disclose. Assylbek Kaliyev: nothing to disclose.