Rapid Endovascular Catheter Core Cooling Combined With Cold Saline as an Adjunct to Percutaneous Coronary Intervention for the Treatment of Acute Myocardial Infarction - CHILL-MI


The goal of the trial was to evaluate a strategy of hypothermia in addition to primary percutaneous coronary intervention (PCI) compared with primary PCI alone among patients with ST-segment elevation myocardial infarction (STEMI).


Hypothermia will reduce infarct size.

Study Design

  • Randomized
  • Parallel

Patient Populations:

  • Patients between 18 and 75 years of age with STEMI presenting within 6 hours of symptom onset

Number of enrollees: 120
Mean patient age: 57 years
Percentage female: 21%


  • Cardiac arrest
  • Previous myocardial infarction
  • Previous coronary revascularization
  • Congestive heart failure
  • End-stage renal or liver disease
  • Recent stroke
  • Coagulopathy, pregnancy, or Killip class II-IV at presentation

Primary Endpoints:

  • Infarct size and myocardium at risk assessed by cardiac magnetic resonance imaging at 4 days

Secondary Endpoints:

  • Death and heart failure
  • Pulmonary edema
  • Infection
  • Bleeding

Drug/Procedures Used:

Patients with STEMI were randomized to hypothermia in addition to primary PCI (n = 61) versus primary PCI alone (n = 59).

Cooling arm: The goal was to cool to ≤35°C prior to PCI. Patients received 1-2 liters of intravenous cold saline and endovascular cooling through a 14 Fr sheath inserted in the femoral vein. Patients also received buspirone 30 mg oral and meperidine 25 mg intravenous as needed to reduced shivering. Cooling continued for 1 hour after reperfusion, at which time patients were spontaneously rewarmed.

Principal Findings:

Overall, 120 patients were randomized. The mean age was 57 years, 21% were women, 13% had diabetes, 38% presented as an anterior STEMI, onset of symptoms to reperfusion was 132 minutes, and 75% received a drug-eluting stent.

Randomization to balloon time was increased by 9 minutes in the cooling group. The mean temperature in the cooling group was 34.7°C at the time of reperfusion.

The primary outcome of infarct size/myocardium at risk was 40.6% in the cooling group versus 46.6% in the control group (p = 0.15). There was a suggestion of benefit among patients that had primary PCI within 4 hours of symptom onset (40.5% vs. 51.6% [p = 0.049], respectively, for cooling vs. control). Among patients who received primary PCI within 4 hours for inferior STEMI, there was no benefit (p = NS); however, among patients who received primary PCI within 4 hours for anterior STEMI, there was suggestion of benefit (p = 0.046).

Death or heart failure occurred in two patients in the hypothermia group versus eight patients in the control group (p = 0.047). Ventricular tachycardia/fibrillation occurred in 8% versus 3%, respectively, for cooling versus control.


Among patients with STEMI, hypothermia in addition to primary PCI did not reduce the primary outcome of infarct size/myocardium at risk. There was a suggestion of benefit among patients with anterior STEMI who received primary PCI within 4 hours of symptom onset. There were few clinical events in this small pilot study. Further study is warranted.


Erlinge D, Götberg M, Lang I, et al. Rapid endovascular catheter core cooling combined with cold saline as an adjunct to percutaneous coronary intervention for the treatment of acute myocardial infarction (The CHILL-MI trial). J Am Coll Cardiol 2014;Feb 5:[Epub ahead of print].

Presented by Dr. David Erlinge at the Transcatheter Cardiovascular Therapeutics meeting (TCT 2013), San Francisco, CA, October 30, 2013.

Keywords: Buspirone, Shivering, Drug-Eluting Stents, Femoral Vein, Myocardium, Cold Temperature, Percutaneous Coronary Intervention, Tachycardia, Ventricular, Inferior Wall Myocardial Infarction, Hypothermia, Heart Failure, Meperidine, Diabetes Mellitus

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