Recent observational studies have found an association between general anaesthesia and increased post-operative mortality in acute ischemic stroke patients undergoing endovascular treatment. It is unknown whether there is a causal relationship in this observation. The investigators are performing a large randomised trial of general versus local anaesthesia to definitively answer the question of whether anaesthetic type alters perioperative outcome.

Inclusion Criteria:

• Patients with AIS scheduled to receive emergency endovascular treatment, older than 18; the onset time is within 12 hours.

Exclusion Criteria:

• Radiological ambiguity concerning infarction and vessel occlusion.
• Additional intracerebral hemorrhage.
• Posterior circulation infraction.
• Coma on admission (Glasgow coma score less than 8).
• NIHSS less than 10 or more than 35.
• Severe agitation or seizures on admission.
• Obvious loss of airway protective reflexes and/or vomiting on admission.
• Being intubated before treatment on admission.
• Known allergy to anesthetic or analgesic.