Stroke risk after abrupt internal carotid artery sacrifice: accuracy of preoperative assessment with balloon test occlusion and stable xenon-enhanced CT.

TLDR

The study evaluates whether stable xenon‑enhanced CT cerebral blood flow combined with balloon test occlusion can predict stroke risk during internal carotid artery sacrifice. Thirty‑one normotensive patients underwent abrupt internal carotid artery occlusion below the ophthalmic artery, with preoperative assessment consisting of a 15‑minute balloon test occlusion followed by xenon‑CT cerebral blood flow imaging. The protocol identified one fatal stroke in a patient with low xenon‑CT CBF despite a positive balloon test, and among 31 patients, 30 passed both tests; three patients developed flow‑related infarctions (two asymptomatic, one with mild hemiparesis), and the protocol significantly lowered infarction and death rates compared with controls, though its false‑negative rate was 3.3–10 % and it missed small border‑zone infarctions and thromboembolic strokes.

Abstract

PURPOSE To evaluate stable xenon-enhanced CT cerebral blood flow with balloon test occlusion as a predictor of stroke risk in internal carotid artery sacrifice. METHODS Abrupt internal carotid artery occlusion was performed by surgical or endovascular means below the origin of the ophthalmic artery in 31 normotensive patients who were assessed preoperatively by a 15-minute clinical balloon test occlusion followed by an internal carotid artery-occluded xenon CT cerebral blood flow study. RESULTS One patient, who passed the clinical test occlusion but exhibited regions of cerebral blood flow less than 30 mL/100 g per minute on the occlusion xenon CT cerebral blood flow study went on to have a fatal stroke corresponding exactly to the region of reduced blood flow. Thirty patients passed both components of the preoperative stroke-risk assessment. Neuroimaging demonstrated possible flow-related infarctions, which subsequently developed in three patients. Two patients were asymptomatic, and one patient was left with a mild residual hemiparesis. CONCLUSIONS Our protocol provided a statistically significant reduction in subsequent infarction rate and infarction-related death rate when compared with a control group of normotensive abrupt internal carotid artery occlusion patients who did not undergo any preoperative stroke-risk assessment (reported in the literature). The estimated false-negative rate for our preoperative assessment protocol ranged from 3.3% to 10% depending on the assessment of the cause of the three potentially flow-related infarctions. Although life-threatening major vascular territory infarctions have been avoided, our protocol is less sensitive to changes predicting smaller, often minimally symptomatic, vascular border zone infarctions and does not predict postoperative thromboembolic strokes.