Glucose-insulin-potassium (GIK) solution, given by paramedics very early after symptom onset in patients with an acute coronary syndrome (ACS), can reduce the risk for cardiac arrest or death by 50% during the first 30 days after the ACS event, according to results of a new study presented at the 2012 American College of Cardiology meeting.
Although the treatment did not prevent myocardial infarction (MI), the GIK solution did reduce infarct size, said co–lead investigator Harry Selker, MD, MSPH, Executive Director of the Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Boston.
The IMMEDIATE (Immediate Myocardial Metabolic Enhancement During Initial Assessment and Treatment in Emergency Care) clinical trial was funded by the National Heart, Lung, and Blood Institute.
GIK Solution Costs Approximately $50
Previous clinical trials have shown no consistent effect with GIK, likely because it was given to patients in the hospital approximately 6 hours after the onset of ischemia, which was too late to help. IMMEDIATE was the first trial to test real-world effectiveness of administering GIK at the very first signs of an ACS in the community.
“Because the trial is the first to show GIK as effective when used by paramedics in real-world community settings, it could have important implications for the treatment of heart attacks,” said Dr Selker.
For the study, paramedics in 36 emergency medical services (EMS) systems in 13 cities across the United States were trained to administer GIK after determining that a patient was likely having an ACS using electrocardiograph-based criteria and thrombolytic predictive instrument decision support that prints patient-specific predictions in addition to an electrocardiogram. The paramedics used the predictive instruments to decide if a patient would likely benefit from treatment. There were 911 patients randomized to receive either GIK or placebo.
At 30 days, a similar proportion of patients in each group progressed to MI (49% in the GIK group vs 53% in the placebo group), but cardiac arrest or hospital mortality occurred in only 4% of patients receiving the GIK solution compared with 9% of those in the placebo group, for a 52% reduction in risk (Table).
Patients randomized to receive GIK were 40% less likely to have cardiac arrest, to die, or to be hospitalized because of heart failure. The effect was even more striking for patients with ST-segment elevation MI (STEMI), in whom immediate GIK was associated with a 60% reduction in cardiac arrest or death relative to placebo.
Infarct size as a percentage of leftventricular mass was 10% in the placebo group and only 2% in the GIK group. In the cohort with STEMI, infarct size was reduced from 12% in the placebo group to 3% in the GIK group.
“The risks and side effects rates from GIK are very low,” said Dr Selker, “and GIK is inexpensive, potentially available in all communities, and deserves further evaluation in trials for widespread EMS use.”
The research team will follow up with study participants at 6 and 12 months to evaluate the longer-term benefit of the GIK treatment.