Introduction Acute occlusions of the internal carotid artery can cause mild to severe stroke symptoms, even if the distal intracranial segment remains patent. The acute therapeutic strategies include carotid endarterectomy, endovascular treatment (EVT) or best medical treatment (BMT). However, available data remains limited.

Aim of Study This study was performed to compare treatment effects and procedural safety of EVT and BMT for acute isolated primary occlusions of the ICA below the C7 segment (ipICAO).

Methods This retrospective, multicenter study analyzes patients treated at 20 comprehensive stroke centers in Europe, and Asia between January 1, 2008, to December 31, 2022. Functional outcomes (mRS 0–2) and safety (SICH, mortality) were assessed.

Results 359 patients met the inclusion criteria. The median age was 72 years (IQR, 60–81). The highest frequency of ipICAO were in 69.7% (248) in the C1 segment. In 82% (293) patients were treated with EVT. After EVT for ipICAO distal intracranial embolization occurred in 26.3% (77). Overall, favorable functional outcome (mRS 0–2) and mortality were 41% (108) and 25% (67), respectively. SICH occurred in 7.1% (25). After adjustment no significant treatment effect of EVT over BMT for favorable functional outcome was observed (EVT: Average treatment effect, -1.2%, 95% CI, -0.18 to 0.16; p=0.89). Rates of SICH and mortality did not differ between both treatment arms.

Conclusion In patients with primary isolated occlusions of the carotid artery below the circle of willis, EVT did not reveal a substantial treatment effect over BMT in this retrospective multicenter study.

Disclosure of Interest JF: Consulting fees from Cerenovus, Medtronic, Phenox, Penumbra, Roche, Tonbridge; Participation on a Data Safety Monitoring Board of Stryker, and Phenox; stock holdings for Tegus and Vastrax, Associate Editor for JNIS.