Hypothermia embolic stroke

Meden P., Overgaard K., Pedersen H., and Boysen G. (1994) Effect of hypothermia and delayed thrombolysis in a rat embolic stroke model. Acta Neurol. Scand. 90, 91-98. 

The effect of hypothermia in combination with thrombolytics has also been evaluated in only a few experimental studies. Meden et al. (11) studied differences in thrombolytic effectiveness in a rat embolic stroke model. In this study, 2 h of intraischemic hypothermia was administered with or without thrombolytic therapy. Thrombolysis was initiated at 2 h after ischemia onset. The investigators found that both hypothermia and thrombolysis significantly reduced infarct volume, but they could not demonstrate any added benefit of thrombolysis over hypothermia alone. A recent study by Wang et al. (12) used a focal embolic brain ischemia model to study the effects of minocycline, an antiinflammatory agent, alone or in combination with mild hypothermia (34—35°C started 1 h after embolization, 2-h duration). The results showed that both minocycline and the hypothermia-minocycline combination reduced infarct volume significantly, but no additive effect was observed. 

Wang C. X., Yang T. and Shuaib A. (2003) Effects of minocycline alone and in combination with mild hypothermia in embolic stroke. Brain Res. 963, 327-329. 

Shimizu T., Naritomi H., OeH., et al. (1996) Mild hypothermia prevents the development of cerebral edema and hemorrhagic transformation in acute embolic stroke. Cerebrovasc. Dis. (Suppl 2), 32-178. 

Naritomi H., Shimizu T., and Oe H. (1996) Mild hypothermia therapy in acute embolic stroke a pilot study. J. Stroke Cerebrovasc. Dis. 6, 193-196. 

Schwab et al. used mild hypothermia (33-34°C) in 20 patients with acute severe middle cerebral artery (MCA) infarction for 48-72 h and found mild hypothermia to be safe and feasible (38). Schwab subsequently reported a series of 25 patients with severe MCA infarction treated with the same protocol (39). Intracranial pressure (ICP) was monitored for 3-7 d, and was found to decrease with initiation of hypothermia. ICP increased during re warming in several patients, but not to the levels seen prior to induction of hypothermia. Pneumonia was seen in 40% of patients treated with hypothermia in this trial, which is within the expected range of occurrence in patients with prolonged ventilation (40). Shimizu et al. used mild hypothermia (33°C) in five patients with embolic infarctions involving the internal carotid artery and MCA territories. The hypothermia was maintained for 3-7 d (41). It was found to be safe, but the number of patients was too small to report any efficacy. Another acute stroke trial using convection air to induce mild hypothermia without anesthesia was found to be feasible (42). Temperatures in this trial were reduced only to 35.5°C, and shivering... 

Until now there have been very limited data on the use of hypothermia in moderate stroke. Naritomi and co-workers reported their findings of seven patients treated with hypothermia within the first 6 h after stroke onset (54). Inclusion criteria for this study were embolic occlusion of the MCA proven with angiography or by Doppler ultrasound. The treatment protocol was similar to the others mentioned in the preceding. Six of the seven patients in this group were able to walk without support at the time of discharge. All of these six patients had either a small infarction or infarction without any mass effect on CT during or after hypothermic therapy. 

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