Hypothermia and percutaneous coronary intervention during acute myocardial infarction

Hypothermia has proven to be one of the most potent and consistent adjunctive therapies for infarct size reduction in numerous preclinical studies, when administered prior to reperfusion. The mechanisms leading to protection are multifactorial. Early clinical trials failed to demonstrate a decrease in infarct size, likely due to the difficulty in achieving adequate cooling prior to reperfusion. Post-hoc ana lysis of these trials demonstrated that patients with anterior myocardial infarction that were cooled to less than 35°C at the time of percutaneous coronary intervention showed a significant reduction in infarct size. These results were supported by a recent pilot study that showed a 38% reduction in infarct size in patients with anterior or inferior myocardial infarction, where cooling to less than 35°C was achieved before reperfusion, without significant delay in door-to-balloon time. Hypothermia remains a promising adjunctive therapy to reperfusion for acute myocardial infarction. A major clinical trial is underway to confirm the preliminary results.