Why Hypothermia?

The social and economic burdens of stroke are enormous. Stroke is the second cause of death in the European Union (EU), with over 500,000 deaths each year. Taking the EU27, Croatia, Iceland, Norway, and Switzerland together EUROSTAT estimates, based on hospital discharge reports, a staggering 1.9 million strokes per year, with an estimated 1.33 million new strokes and 0.57 million recurrent events.

Considering that the large majority of stroke patients (80 to 85%) have ischaemic events - these represent about 1.52 million ischaemic strokes every year in Europe. Therefore stroke related disability is clearly dominated ischaemic stroke, and for this reason EuroHYP focuses on ischaemic stroke in order to answer this most pressing need.

Ischaemic stroke is currently considered the largest challenge in the area of cardiovascular disease, due to the very limited number of treatments available to the victims. Intravenous thrombolysis with alteplase is the most prominent treatment strategy, but is available only for a small minority of patients. In addition, about half of the stroke patients remain dependent or die despite thrombolysis. Because stroke incidence rises exponentially with age, the social and economic burden of stroke will rise further with the ageing of the population.

Systematic review of animal studies modeling stroke suggests that therapeutic cooling is the most promising intervention identified to date. In these animal studies, cooling to 35°C reduced infarct size by about one third, and cooling to 34°C by around 45%. Moreover, several prospective observational studies in stroke have shown an association between raised body temperature and poor outcome, and between low body temperature and good outcome. Finally, cooling improves outcome in patients with hypoxic-ischaemic brain injury after cardiac arrest. Hypothermia is therefore the most promising treatment for patients with acute ischaemic stroke.