This study evaluates the outcomes of stroke patients treated for intravascular thrombectomy, using either a local anesthetic with sedation, or a general anesthetic. Historical data will be used for those treated with the local anesthetic, and prospective data will be used for those treated with the general anesthetic.

This is an open-label pilot study, comparing intravascular thrombectomy patients treated using either general anesthetic (prospective arm) or local anesthetic with sedation (retrospective arm), with blinded outcome evaluation.

New evidence has established that the addition of endovascular thrombectomy for large, and/or proximal occlusions improves outcome in addition to, and/or in place of tPA therapy. There have been no randomized prospective trials assessing the relationship of anesthesia on outcomes for this procedure. This procedure is routinely performed under either local anesthetic with sedation and under general anesthesia (GA). The choice between these two techniques is largely institution based. Currently in the Saskatoon Health Region (SHR) endovascular thrombectomies are performed under general anesthesia due to operator preference and the optimization of surgical conditions. In the United States and other Canadian centers, this procedure is performed safely with local anesthesia with or without sedation.

Several retrospective trials have suggested that general anesthetics are associated with poorer outcomes. It has been suggested that general anesthesia can result in a delay in the time to procedural start since it requires the presence of an anesthesiologist and the procedure can be performed under sedation without extra personnel. It is also proposed that the induction of general anesthesia can cause a decrease in blood pressure and a decrease in collateral perfusion which can result in further cellular hypoxia. Anesthesiologists , however, are able to expertly manipulate hemodynamic parameters during general anesthesia to the specific requirements of the operators potentially creating optimal tissue oxygenation conditions.

There is a need for a prospective trial to assess the effect of general anesthetic on patient outcome during endovascular thrombectomy. At this time, it is premature to conduct a randomized controlled trial (RCT). Therefore in this pilot study, adult acute ischemic stroke participants who undergo intravascular thrombectomy in Saskatchewan will receive a general anesthetic as per their current practice, and their data will be collected prospectively. This cohort of participants will then be compared to participants that underwent the same procedure in another study, who received local anesthesia with sedation. Approximately 77 prospective participants will be recruited for the prospective arm of this study.

Inclusion Criteria:

• Acute ischemic stroke
• Age 18 or greater
• Onset (last seen well) time to treatment less than 12 hours
• Disabling stroke defined as a baseline NIHSS > 5 at the time of treatment
• Pre-stroke independent functional status in activities of daily living. Patient must be living in their own home, apartment or seniors lodge where no nursing care is required
• Pre-enrollment non-intubated state based on acceptable GCS for the prospective Cohort
• Small core proximal occlusion as confirmed by CT angiography (carotid, M1 MCA or M1 MCA equivalent)
• Intention to initiate endovascular treatment within 60 minutes of baseline non-contrast CT
• Sevoflurane used during thrombectomy
• Appropriate consent provided

Exclusion Criteria:

• Baseline non-contrast CT reveals a moderate/large core defined as extensive early ischemic changes of ASPECTS 0-5 in the territory of symptomatic intracranial occlusion
• Hemorrhagic stroke
• Clinical history, past imaging or clinical judgment suggests that the intracranial occlusion is chronic
• Intubated state based on GCS at any time prior to induction of general anesthesia for prospective cohort

Adult acute ischemic stroke participants who undergo intravascular thrombectomy in Saskatchewan will be prospectively recruited for the prospective arm.