COOL AMI EU pilot trial: a multicentre, prospective, randomised controlled trial to assess cooling as an adjunctive therapy to percutaneous intervention in patients with acute myocardial infarction

EuroIntervention. 2017 Aug 4;13(5):e531-e539. doi: 10.4244/EIJ-D-17-00279.


Aims: We aimed to investigate the rapid induction of therapeutic hypothermia using the ZOLL Proteus Intravascular Temperature Management System in patients with anterior ST-elevation myocardial infarction (STEMI) without cardiac arrest.

Methods and results: A total of 50 patients were randomised; 22 patients (88%; 95% confidence interval [CI]: 69-97%) in the hypothermia group and 23 patients (92%; 95% CI: 74-99) in the control group completed cardiac magnetic resonance imaging at four to six days and 30-day follow-up. Intravascular temperature at coronary guidewire crossing after 20.5 minutes of endovascular cooling decreased to 33.6°C (range 31.9-35.5°C). There was a 17-minute (95% CI: 4.6-29.8 min) cooling-related delay to reperfusion. In "per protocol" analysis, median infarct size/left ventricular mass was 16.7% in the hypothermia group versus 23.8% in the control group (absolute reduction 7.1%, relative reduction 30%; p=0.31) and median left ventricular ejection fraction (LVEF) was 42% in the hypothermia group and 40% in the control group (absolute reduction 2.4%, relative reduction 6%; p=0.36). Except for self-terminating paroxysmal atrial fibrillation (32% versus 8%; p=0.074), there was no excess of adverse events in the hypothermia group.

Conclusions: We rapidly and safely cooled patients with anterior STEMI to 33.6°C at the time of coronary guidewire crossing. This is ≥1.1°C lower than in previous cooling studies. Except for self-terminating atrial fibrillation, there was no excess of adverse events and no clinically important cooling-related delay to reperfusion. A statistically non-significant numerical 7.1% absolute and 30% relative reduction in infarct size warrants a pivotal trial powered for efficacy.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Cold Temperature*
  • Combined Modality Therapy / methods
  • Female
  • Heart Arrest / etiology
  • Humans
  • Hypothermia, Induced / methods
  • Magnetic Resonance Imaging / methods
  • Male
  • Middle Aged
  • Myocardial Infarction / therapy*
  • Myocardium / pathology
  • Percutaneous Coronary Intervention*
  • Pilot Projects
  • Prospective Studies
  • Time Factors
  • Ventricular Function, Left / physiology