Background: Therapeutic hypothermia has shown potential in cardiac intervention for years; however, its adoption into the neurovascular space has been limited. Studies have pointed to slow cooling and limited depth of hypothermia yielding negative outcomes. Here we present an insulated catheter that allows for consistent infusion of chilled saline directly to the brain. Direct delivery of cold saline allows a faster depth of hypothermia, which could have a benefit to the growth of ischemic lesions.

Methods: Ten canines were randomized to either receive selective brain cooling or no additional therapy. Eight animals were successfully enrolled (n = 4 per group). Each animal underwent a temporary middle cerebral artery occlusion (MCAO) for a total of 45 min. Five minutes prior to flow restoration, chilled saline was injected through the ipsilateral internal carotid artery using an insulated catheter to ensure delivery temperature. The treatment continued for 20 min, after which the animal was transferred to an MRI scanner for imaging.

Results: Of the 8 animals that were successfully enrolled in the study, 3 were able to survive to the 30-day endpoint with no differences between the cooled and control animals. There was no difference in the initial mean infarct size between the groups; however, animals that did not receive cooling had infarcts continuing to progress more rapidly after the MCAO was removed (13.8% vs 161.3%, p = 0.016, cooled vs control).

Conclusions: Selective hypothermia was able to reduce the post-MCAO infarct progression in a canine model of temporary MCAO.