Background: In this study, we aimed to investigate the possible effects of high-dose insulin on cytokine levels (interleukin [IL]-6, IL-10 and tumor necrosis factor-alpha [TNF-a]), cardiac biomarkers (CK-MB, cTnI, AST) and the early-stage prognosis in patients with left ventricular dysfunction who underwent beating heart coronary artery bypass graft (CABG) surgery.

Methods: Between July 2009 and March 2010, a total of 30 patients with reduced left ventricular ejection fraction (LVEF <50%) who underwent beating heart CABG surgery were included in this prospective study. The patients were divided into two subgroups, including treatment and control arms. Eighteen patients (15 males, 3 females; mean age 63.1±11 years; range 40 to 79 years) received glucose-insulin-potassium (GIK) infusion in the treatment arm, whereas 12 patients (9 males, 3 females; mean age 58.6±13.4 years, range 41 to 79) did not receive GIK infusion among controls. Following the induction of anesthesia at a rate of 1 mL/kg/h, all patients were also administered 500 mL of dextrose solution (20%) in combination with crystallized insulin in 40 IU and potassium 40 mEq/L over 24 hours in the treatment arm. CK-MB, AST, cTnI, IL-6, IL-10 and TNF-a levels were measured (i) in the pre-induction phase, (ii) following surgery and (iii) at 24 hours of intensive care unit (ICU) stay. The number of inotropic and vasodilator infusions and the use of intra-aortic balloon pumps during surgery and within 24 hours after surgery, and the duration of ICU stay and hospital were recorded.

Results: In the treatment arm, IL-6, IL-10 and TNF-a level were similar to those of controls. The number of inotropic infusions during surgery and in the ICU, as well as the duration of ICU stay, was also similar between the groups.

Conclusion: Our study results suggest that GIK infusion has no preventive effect in the patients with left ventricular dysfunction who underwent beating heart CABG surgery. The study also shows that high-dose insulin has no any antiinflammatory effect. However, further large-scale studies are required to establish possible effects of insulin on cytokine levels in this population.

Keywords : Coronary artery bypass graft surgery; glucose-insulinpotassium; interleukin 10; interleukin 6; TNF-alpha