A pilot study of rapid cooling by cold saline and endovascular cooling before reperfusion in patients with ST-elevation myocardial infarction

Background— Experimental studies have shown that induction of hypothermia before reperfusion of acute coronary occlusion reduces infarct size. Previous clinical studies, however, have not been able to show this effect, which is believed to be mainly because therapeutic temperature was not reached before reperfusion in the majority of the patients. We aimed to evaluate the safety and feasibility of rapidly induced hypothermia by infusion of cold saline and endovascular cooling catheter before reperfusion in patients with acute myocardial infarction. Methods and Results— Twenty patients with acute myocardial infarction scheduled to undergo primary percutaneous coronary intervention were enrolled in this prospective, randomized study. After 4±2 days, myocardium at risk and infarct size were assessed by cardiac magnetic resonance using T2-weighted imaging and late gadolinium enhancement imaging, respectively. A core body temperature of P =0.12). Despite similar duration of ischemia (174±51 minutes versus 174±62 minutes, hypothermia versus control, P =1.00), infarct size normalized to myocardium at risk was reduced by 38% in the hypothermia group compared with the control group (29.8±12.6% versus 48.0±21.6%, P =0.041). This was supported by a significant decrease in both peak and cumulative release of Troponin T in the hypothermia group ( P =0.01 and P =0.03, respectively). Conclusions— The protocol demonstrates the ability to reach a core body temperature of Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00417638.