Postoperative N-terminal pro-brain natriuretic peptide level in coronary artery bypass surgery with ventricular dysfunction after perioperative glucose-insulin-potassium treatment

Objective: The aim of this study was to clarify the efficacy of perioperative glucose-insulin-potassium (GIK) infusion on preoperative and postoperative N-terminal (NT)-pro-brain natriuretic peptide (BNP) concentrations in patients with a low ejection fraction undergoing isolated on-pump coronary artery bypass graft (CABG) surgery.

Design: A double-blind, randomized, controlled study.

Setting: Modarres Hospital, Tehran, Islamic Republic of Iran.

Patients: Sixty-six patients with a low ejection fraction who required coronary artery surgery were selected.

Intervention: Patients were allocated to a GIK (n = 36) or a control (n = 30) group. The GIK group received GIK solution (500 mL of dextrose in water (DW) 10% + 40 U of regular insulin + 40 mEq of KCl, and 2 g of MgSO(4)) at a rate of 1 mL/kg/h for 10 hours preoperatively and until the removal of the aortic cross-clamp. The control group received half saline solution as placebo with an equivalent infusion rate during the same interval.

Measurements and main results: Serum NT-proBNP levels were measured before starting the GIK, at the time of anesthesia induction, and 24 hours after surgery. The primary outcome measures were preoperative and postoperative NT-proBNP level. The amount of elevation in postoperative NT-proBNP concentrations was less prominent in the GIK group than in the control group (2,601 ± 1,799 pg/mL v 4,732 ± 4,127 pg/mL; p = 0.02). The patients in the GIK group were extubated sooner (495 ± 92 minutes) than the control group (774 ± 224 minutes; p = 0.002). The overall extubation time was 606 ± 177 minutes. Delayed requirement for mechanical ventilation was significantly more in the controls compared with the GIK group (45.8% v 13.9%, p = 0.004).

Conclusions: GIK is of value in the reduction of post-cardiac surgery NT-proBNP elevation. Thus, its infusion should have a protective effect in patients with low ejection fraction undergoing CABG surgery. Further studies may prove GIK infusion benefits in high-risk CABG surgery patients optimize outcome.