Intra-arterial Selective Hypothermic Magnesium Sulfate Infusion in Combination With Endovascular Thrombectomy in Acute Ischemic Stroke

The primary objective of this study is to estimate the safety and effectiveness of selective intra-arterial hypothermic magnesium sulfate infusion after endovascular thrombectomy in patients with acute ischemic stroke. Addendum regarding phase 1 dosing implementation and planned phase 2 design: This integrated phase 1/2 trial originally planned weight-individualized magnesium perfusate calculated as Target Mg (μmol/mL) = 0.6 × patient body weight. During phase 1 recruitment, no dedicated emergency pharmacy fast-track compound workflow existed for urgent EVT procedures, which would cause reperfusion delay if individualized mixing was performed intraoperatively. Therefore, a uniform fixed magnesium concentration of 20.29 mmol/L was adopted as a temporary operational solution for all 9 phase 1 participants, with dose escalation only performed by increasing total infusion volume (350/500/650 mL). For the upcoming phase 2 cohort, we will retain the fully safe 650 mL maximum infusion volume and conduct independent magnesium concentration escalation across six ascending tiers: 20.29, 22.54, 25.36, 28.98, 33.81, and 40.57 mmol/L. These concentrations are prepared by diluting the standard 5 g magnesium stock into 1000 mL, 900 mL, 800 mL, 700 mL, 600 mL, and 500 mL pre-cooled normal saline respectively. After defining the maximum tolerated magnesium concentration tier, the original weight-tailored compounding formula will be fully implemented for subsequent efficacy cohorts. All protocol adjustments have received institutional review board amendment approval.