Therapeutic hypothermia is a "safe and feasible" course of treatment for ST-elevation myocardial infarction (STEMI) patients, according to results of the CHILL-MI trial presented Oct. 30 presented as part of TCT 2013 in San Francisco.

The trial examined 120 patients from nine centers who suffered from large anterior and inferior STEMIs and an infarct that lasted less than six hours. The patients were then randomized into two groups: normal treatment and therapeutic hypothermia treatment. The first group underwent percutaneous coronary intervention (PCI) without rapid cooling. Rapid cooling for the second group, which consisted of 2,000 ml cold saline as well as endovascular cooling to reach a goal temperature of 33°C, began one hour prior to the patient undergoing PCI and lasted one hour after reperfusion.

The hypothermia group saw a minimal increase in door-to-balloon time impact of about nine minutes as well as a 13 percent (p=0.15) drop in infarct size relative to the area at risk. Although the investigators did not achieve a primary endpoint of infarct size/myocardium at risk (IS/MaR) assessed by cardiac magnetic resonance imaging at 4±2 days in the total study population, according to a TCT press release, "exploratory analysis indicates an effect in the early anterior patient population with a 33 percent reduction of infarct size."

"Hypothermia using intravenous cold saline and an endovascular venous cooling catheter was safe, feasible and reduced temperature to 34.7°C before reperfusion, with a delay of reperfusion of nine minutes," said lead investigator David Erlinge, MD, PHD, FACC, professor in the department of cardiology at Lund University and Skane University Hospital in Sweden. "Although reduction in infarct size in relation to area at risk did not reach significance, we found a significant reduction in the incidence of clinical heart failure," he adds. "Furthermore, we observed a large reduction in infarct size in the anterior patient population, but this needs to be validated in a prospective study."

The CHILL-MI trial stems from the pilot RAPID MI-ICE trial which found reduced infarct size in patients who were cooled under 35°C prior to undergoing angioplasty.

Keywords: Incidence, Myocardial Infarction, Temperature, San Francisco, Hypothermia, Heart Failure, Angioplasty, Magnetic Resonance Imaging, Percutaneous Coronary Intervention

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