Post-thrombectomy angiography-derived fractional flow is associated with functional outcomes in ICAS-related large vessel occlusion

Background Optimal management of residual stenosis after successful thrombectomy in intracranial atherosclerotic stenosis (ICAS)-related large vessel occlusion (LVO) remains uncertain. We evaluated whether post-thrombectomy angiography-derived fractional flow (FF) was associated with 90-day functional independence in anterior circulation ICAS-LVO and whether FF outperformed anatomic stenosis measures. Materials and methods This retrospective analysis of a prospectively maintained registry included consecutive patients with anterior circulation ICAS-LVO who achieved successful reperfusion after thrombectomy between October 2024 and June 2025. Post-thrombectomy FF was computed using AccuICAD V1.0 software. Receiver operating characteristic analysis with the maximum Youden index identified the optimal FF cut-off for predicting 90-day functional independence, defined as a modified Rankin Scale (mRS) score ≤2. Patients were dichotomized into two groups: a low-FF (FF ≤0.94) group and a high-FF (FF >0.94) group. Multivariable logistic regression and receiver operating characteristic analyses were performed. Results Among 105 patients (mean age, 66 years±11; 81 men), 90-day functional was observed in 22 of 48 patients (45.8%) in the low-FF group and 48 of 57 patients (84.2%) in the high-FF group (P<0.001). After full adjustment, high-FF remained independently associated with functional independence (OR, 4.46; 95% CI: 1.5–13.3; P=0.008). FF showed better discrimination than diameter and area stenosis rate (area under the curve (AUC) 0.761 vs 0.657 vs 0.660, respectively; P=0.03 and P=0.04). Conclusion Higher post-thrombectomy FF was associated with better 90-day outcomes in anterior circulation ICAS-LVO and may provide a physiologic marker of residual lesion significance. Further validation is needed.