BACKGROUND: The administration of insulin has been shown to exert cardioprotective and immunomodulatory properties. Ischemia and inflammation are typical features of acute coronary syndrome, thus it was hypothesized that high-dose glucose-insulin-potassium (GIK) treatment could suppress the systemic inflammatory reaction and attenuate myocardial ischemia-reperfusion injury in patients with unstable angina pectoris after urgent coronary artery bypass surgery. METHODS: Forty patients with unstable angina pectoris scheduled for urgent coronary artery bypass surgery and cardiopulmonary bypass were randomly assigned to receive either high-dose insulin treatment (short-acting insulin 1 IU/kg/h with 30% glucose 1.5 ml/kg/h administered separately) or control treatment (saline). Blood glucose levels were targeted to 6.0-8.0 mmol/l in both groups by adjusting the rate of glucose infusion in the GIK group and by additional insulin in the control group as needed. RESULTS: High-dose insulin treatment was associated with significantly lower average C-reactive protein (23.8 vs. 40.1 mg/l, P= 0.008) and free fatty acid levels (0.22 vs. 0.41 mmol/l, P=