Intraoperative hemispheric circulation time as a potential predictor of aneurysm occlusion after flow diverter treatment in large internal carotid artery aneurysm

Intraoperative prediction of aneurysm occlusion after flow diverter (FD) placement may enable real-time adjustment of treatment strategies, such as adding an overlapping FD, to optimize efficacy outcomes. This study investigated whether the hemispheric circulation time (ΔHCT) calculated from intraoperative digital subtraction angiography (DSA) could serve as an intraoperative predictor of postprocedural aneurysm occlusion. Patients who underwent FD placement for large (≥ 10 mm) internal carotid artery (ICA) aneurysms without adjunctive coiling between January 2015 and December 2022 were retrospectively analyzed. ΔHCT was defined as the difference in contrast arrival time from the ICA horizontal intrapetrous segment to the superior sagittal sinus on lateral DSA before and after FD deployment. The relationship between ΔHCT and adequate occlusion (OKM grade C–D) at 1 year was evaluated. Seventy aneurysms were included. Adequate occlusion was achieved in 55 patients (78.6%) at 1 year. In univariate analysis, the change in ΔHCT following FD deployment was significantly higher in the adequate occlusion group than in the inadequate occlusion group (1.00 s vs. 0.25 s, p < 0.0001). ROC analysis yielded an area under the curve of 0.872 (95% CI, 0.777–0.967), with sensitivity of 0.83 and specificity of 0.80 for predicting adequate occlusion. Multivariable logistic regression analysis identified ΔHCT > 0.5 s as independently associated with adequate occlusion (odds ratio 20.2, 95% confidence interval 4.54–89.8, p = < 0.001). Intraoperative DSA-based ΔHCT analysis provides a practical and quantitative indicator for predicting aneurysm occlusion after FD placement in routine clinical practice.