Background and purpose: Therapeutic hypothermia improves outcomes in experimental stroke models, especially after ischemia-reperfusion injury. We investigated the clinical and radiological effects of therapeutic hypothermia in acute ischemic stroke patients after recanalization.
Methods: A prospective cohort study at 2 stroke centers was performed. We enrolled patients with acute ischemic stroke in the anterior circulation with an initial National Institutes of Health Stroke Scale≥10 who had successful recanalization (≥thrombolysis in cerebral ischemia, 2b). Patients at center A underwent a mild hypothermia (34.5°C) protocol, which included mechanical ventilation, and 48-hour hypothermia and 48-hour rewarming. Patients at center B were treated according to the guidelines without hypothermia. Cerebral edema, hemorrhagic transformation, good outcome (3-month modified Rankin Scale, ≤2), mortality, and safety profiles were compared. Potential variables at baseline and during the therapy were analyzed to evaluate for independent predictors of good outcome.
Results: The hypothermia group (n=39) had less cerebral edema (P=0.001), hemorrhagic transformation (P=0.016), and better outcome (P=0.017) compared with the normothermia group (n=36). Mortality, hemicraniectomy rate, and medical complications were not statistically different. After adjustment for potential confounders, therapeutic hypothermia (odds ratio, 3.0; 95% confidence interval, 1.0-8.9; P=0.047) and distal occlusion (odds ratio, 7.3; 95% confidence interval; 1.3-40.3; P=0.022) were the independent predictors for good outcome. Absence of cerebral edema (odds ratio, 5.4; 95% confidence interval, 1.6-18.2; P=0.006) and no medical complications (odds ratio, 9.3; 95% confidence interval, 2.2-39.9; P=0.003) were also independent predictors for good outcome during the therapy.
Conclusions: In patients with ischemic stroke, after successful recanalization, therapeutic hypothermia may reduce risk of cerebral edema and hemorrhagic transformation, and lead to improved clinical outcomes.
Keywords: hypothermia; ischemia; ischemic; neuroprotection; reperfusion injury; stroke.