Introduction Sub-clinoid proximal occlusion is defined by internal carotid artery (ICA) occlusion with intact Circle of Willis flow. We hypothesise that such cases of large vessel occlusion provide collateral blood flow to preserve the ischaemic penumbra and may benefit from endovascular clot retrieval (ECR) beyond 24 hours.

Method We retrospectively searched the stroke database from 2018 at Calvary Hospital, Canberra, Australia for ECR cases performed beyond 24 hours from symptom onset.

Results Two patients were identified from the registry data.

64-year-old man awoke with left hemiparesis and was last seen well 9.5 hours prior. ECR for ICA occlusion was not initially performed due to rapidly improving National Institute of Health Stroke Scale (NIHSS) of three to zero. ECR was later performed at 38.5 hours for clinical deterioration. Stroke aetiology was atrial fibrillation. At 90-day NIHSS and modified Rankin Scale (mRS) were three.

75-year-old man awoke with left hemiparesis and was last seen well 10 hours prior. Baseline NIHSS was four. Off-label thrombolysis was administered based on salvageable penumbra on CTP, however ECR for ICA occlusion was not performed as neurointervention was unavailable. After 24 hours his NIHSS score improved to one but hemispheric hypoperfusion persisted on CTP. At 36 hours he underwent ECR with carotid stenting. Stroke aetiology was large-vessel atherosclerosis. At 90 days his NIHSS and mRS were zero.

Conclusion Acute sub-clinoid proximal carotid occlusion requires tissue viability assessment with imaging to guide decision of ECR beyond 24 hours and may be of benefit.