MAnagement of Systolic Blood Pressure During Thrombectomy by Endovascular Route for Acute Ischaemic STROKE

Stroke is the third most common cause of death in New Zealand and is one of the leading causes of long-term disability at all ages. A life-saving clot retrieval procedure can save lives and prevent disability of patients with ischaemic stroke who get to hospital in time. In New Zealand, 90% of clot retrieval procedures are performed under general anaesthesia. Many anaesthetic drugs can affect blood pressure (BP) and blood flow within the brain. Increasing BP during the procedure could provide additional benefits in this devastating disease. A large trial is needed to investigate BP management during clot retrieval.

Internationally stroke ranks second among all causes of disability and is adding to considerable worldwide healthcare burden. Over the last 5 years a new procedure to remove clots (Endovascular Thrombectomy - EVT) has been effective for the treatment of acute large strokes, with significant reductions in long term patient disability compared to standard treatment. However, there minimal guidance on blood pressure management during the procedure. The brain is especially vulnerable to low blood pressure during the acute stroke period due to low blood supply, impairment of how the brain regulates blood flow and further falls in blood flow to the brain. High blood pressure may be beneficial due to increased blood flow in areas at risk during this time. It could be harmful due to brain injury process, swelling, and bleeding into the brain. Conversely, relatively low blood pressure could be harmful. Current evidence is limited to large observational studies. This randomised controlled study will examine the safety and efficacy of two systolic blood pressures (SBP) management arms during general anaesthesia for EVT on outcomes in patients with acute ischaemic stroke.

Inclusion Criteria: * Patients diagnosed with anterior circulation stroke (ICA or proximal M1 or M2 segment of MCA) treated with ECR within 6 hrs of stroke onset and ECR patients presenting within 6-24 hours and favourable penumbra on perfusion scanning (see criteria 1-3). Additional criteria in the 6 to 24-hour window. 1. 'wake up' stroke; CT with no (or at most minimal) acute infarction or 2. patient 80 years or older (NIHSS of 10 and infarct volume less than 21 ml on DWI or CT perfusion-CBF) 3. patient less than 80 years (NIHSS of 10 and infarct volume less than 31 ml on DWI or CT perfusion-CBF NIHSS of 20 and infarct volume less than 51 ml on DWI or CT perfusion-CBF). Exclusion Criteria: * Rescue"' procedures eg acute ischaemic stroke associated with major medical procedures such as coronary artery stenting and coronary artery bypass * pre-stroke mRS\>=3 * not having GA * terminal illness with expected survival \<1 year * pregnancy * cardiovascular conditions where BP targeting will be contra-indicated * unable to participate in 3-month follow up