Intravascular Cooling in the Treatment of Stroke
What is the impact of a faster therapeutic hypothermia in stroke patients?
Safety procedures and 4°C saline infusions for faster cooling were added to the ICTuS trial (Intravascular Cooling in the Treatment of Stroke) protocol. A femoral venous intravascular cooling catheter after intravenous recombinant tissue-type plasminogen activator in eligible patients provided 24 hours of cooling followed by a 12-hour rewarm. Serial safety assessments and imaging were performed. The primary endpoint was 3-month modified Rankin score of 0, 1. A further prespecified analysis was a hypothesis that pneumonia risk could be predicted by the initial 24-hour rise in high-sensitivity C-reactive protein as a biomarker.
Of the intended 1,600 subjects, 120 were enrolled before the study was stopped. Randomly, 63 were to receive hypothermia plus anti-shivering treatment and 57 were to receive normothermia. Compared with previous studies, cooling rates were improved with a cold saline bolus, without fluid overload. The intention-to-treat primary outcome of 90-day modified Rankin score 0, 1 occurred in 33% hypothermia and 38% normothermia subjects (odds ratio, 0.81; 95% confidence interval [CI], 0.36–1.85). Serious adverse events occurred equally. Mortality was 15.9% in hypothermia and 8.8% in normothermia subjects (OR, 1.95; 95% CI, 0.56–7.79). Pneumonia occurred in 19% hypothermia versus 10.5% in normothermia subjects (OR, 1.99; 95% CI, 0.63–6.98).
The authors concluded that intravascular therapeutic hypothermia was confirmed to be safe and feasible in recombinant tissue-type plasminogen activator–treated acute ischemic stroke patients.
The ICTuS-2 trial was stopped early because of significant changes in standard care of acute ischemic stroke. Although the data were insufficient to permit any statistically significant findings, it seems that protocol measures designed to prevent pneumonia failed. Whether the explanation lies with therapeutic hypothermia or the sedating, anti-shivering protocol is unclear. Additional studies are indicated to develop an effective, safe therapeutic hypothermia regimen for acute stroke.
Keywords: Biological Markers, C-Reactive Protein, Hypothermia, Hypothermia, Induced, Intention to Treat Analysis, Ischemia, Pneumonia, Primary Prevention, Stroke, Tissue Plasminogen Activator, Vascular Diseases
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