NeuroNews — Ron Solar (ThermopeutiX, San Diego, USA) and colleagues report in EuroIntervention that the TwinFlo catheter (ThermopeutiX), in pigs, was associated with rapid, selective, deep cerebral hypothermia. They add that the catheter may “offer an improved method for neuroprotection during neurosurgery, cardiac arrest, acute stroke, and other ischaemic insult”. Solar talks to BIBA Briefings about the role of hypothermia in neuroprotection.
Why might hypothermia be an effective method of neuroprotection in patients with acute stroke?
There are many pathways that lead from arterial occlusion to cell death, and most of these pathways are metabolically controlled. In the laboratory, hypothermia has been shown to be the most robust method of neuroprotection to date because it acts on most, if not all of these pathways; as these pathways are metabolically controlled, lowering the temperature slows metabolism.
Presumably, there is a limited time window in which hypothermia can be used in acute stroke patients?
Yes, the sooner the brain can be cooled, the better the outcome. Ideally, cooling should occur before recanalisation as hypothermia has been shown to prevent reperfusion injury. However, many experimental studies have shown significant benefits of therapeutic hypothermia even when initiated later. In our pig studies, cooling commenced three and a half to five hours after occlusion and infarct size was significantly reduced compared with a normothermic control. In a first-in-human series of refractory cardiac arrest “rescue” cases, selective cooling with the TwinFlo catheter was initiated up to 13 hours after the arrest with outstanding outcomes.