Triage of acute ischemic stroke (AIS) patients is critical, to decrease time to treatment, and improve functional outcome. The therapeutic standard of care for AIS consecutive to large vessel occlusion (LVO) is the association of intravenous (IV) alteplase administration and mechanical thrombectomy (MT). However, there are limited places where MT can be performed. Therefore, there is a need for innovative tools to identify, in the ambulance, patients with LVO that require MT. Sending the patients at the right, avoiding futile stops (i.e. in places where MT is not available), is definitively a strategy that saves time.

There is currently no biomarker nor Point Of Care (POC) Lab Testing to solve this issue and clinical scoring methods such as the NIHSS have a low accuracy rate to detect LVO. The relevance of blood biomarkers for LVO diagnosis and therapeutic decisions needs to be confirmed for effective triage in the setting of AIS with LVO, which represent 30% of all AIS.

The main objective of our study is to determine diagnostic performances of a panel of selected blood biomarkers to identify patients with AIS consecutive to LVO among those with stroke suspicion, within 24 hours of stroke symptom's onset before brain imaging.

This could facilitate the triage of patients with LVO refractory to thrombolysis treatment, who may benefit most from MT.

Inclusion Criteria:

• Symptoms consistent with stroke <24 hours
• Adult patients ≥ 18 years old
• Non opposition of the patient or his/her relatives to the research (emergency inclusion procedure)

Exclusion Criteria:

• Patient under guardianship or curatorship

Patients with stroke suspicion within 24 hours of stroke's symptoms