News | April 30, 2013

Philips Completes Enrollment in Therapeutic Hypothermia Clinical Study for Heart Attack Patients

CHILL-MI study to further evaluate the safety and effectiveness of the InnerCool RTx endovascular cooling system to reduce reperfusion injury in acute STEMI patients

April 30, 2013 — Philips Healthcare has completed patient enrollment in the CHILL-MI clinical study designed to further evaluate the safety and effectiveness of the company’s InnerCool RTx endovascular cooling system in patients with ST-elevation myocardial infarction (STEMI). 

Preventing heart tissue damage is a significant unmet medical need in the treatment of acute myocardial infarction. Endovascular cooling is a method for quickly achieving therapeutic hypothermia – reducing a patient’s body temperature to help lower the amount of tissue injury.

This prospective, randomized study enrolled 120 patients in nine European centers. Patients received immediate percutaneous coronary intervention (primary PCI) with or without adjunctive rapid endovascular cooling. 

The primary endpoint of the study is reduction of myocardial infarct size as a percentage of myocardium at-risk, assessed by cardiac magnetic resonance imaging (MRI) at four days (± two days). Secondary safety and efficacy endpoints are also being evaluated. Principal investigators for the study are David Erlinge, M.D., Ph.D., professor of cardiology and Goran Olivecrona, M.D., Ph.D., from the department of cardiology, Lund University in Lund, Sweden.  

Previous research has shown that therapeutic hypothermia can reduce infarct size in patients whose body temperature reaches ?35°C prior to reperfusion or opening of the blocked artery. The previously published Rapid MI-ICE study, which utilized the InnerCool system, showed a 38 percent reduction in infarct size in STEMI patients who were cooled to a body temperature of ?35°C before primary PCI.[1]

"Therapeutic hypothermia is the most promising therapy to reduce infarct size in STEMI patients,” said Erlinge.

Acute myocardial infarction (AMI) is one of the leading causes of mortality, with STEMI being the most severe form of AMI. In the United States and Europe, the incidence of STEMI is 770-800 per million respectively.[2],[3] In hospital, mortality for STEMI patients ranges between 4.2-13.5 percent.[4, 5] Initiating percutaneous coronary intervention or primary PCI as early as possible is critical to the survival of heart tissue. 

The Philips InnerCool RTx endovascular system cools patients from the inside out. A heat-exchange catheter with an integrated temperature sensor is positioned below the heart via the femoral vein and connected to a proprietary console. The closed-loop system rapidly cools the patient and monitors core body temperature without fluid introduction or exchange by circulating cool saline in the catheter.

For more information:



1. Götberg, M et al. "A pilot study of rapid cooling by cold saline and endovascular cooling before reperfusion in patients with ST-elevation myocardial infarction (RapidMI-ICE)." Circ Cardiovasc Interv. 2010 Oct;3(5):400-407.

2. McManus, DD, et al.  "Recent Trends in the Incidence, Treatment, and Outcomes of Patients with STEMI and NSTEMI."  Am J Med. 2011 Jan;124(1):40-47. 

3. Widmisky, P, et al.  Reperfusion Therapy for ST Elevation Acute Myocardial Infarction in Europe: Description of the current situation in 30 countries. Eur Heart J. 2010 Apr;31(8):943-957.

4. Widmisky, P, et al.  "Reperfusion Therapy for ST Elevation Acute Myocardial Infarction in Europe: Description of the current situation in 30 countries." Eur Heart J. 2010 Apr;31(8):943-957.

5. Bhatt, NS, et al. "Comparison of In-Hospital Outcomes with Low-Dose Fibrinolytic Therapy Followed by Urgent Percutaneous Coronary Intervention Versus Percutaneous Coronary Intervention Alone for Treatment of ST-Elevation Myocardial Infarction." Am J Cardiol. 2013 Mar 10. pii: S0002-9149(13)00524-9.