Cardioprotective Effects of Nicorandil in Patients Undergoing On-Pump Coronary Artery Bypass Surgery

Objective: The purpose of this study was to assess the cardioprotective effects of nicorandil in patients undergoing coronary artery bypass graft (CABG) surgery with cardiopulmonary bypass (CPB).

Design: A prospective, double-blind, randomized clinical study.

Setting: A university hospital.

Participants: Thirty-two patients undergoing elective CABG surgery.

Interventions: Patients were randomized into 2 groups: the nicorandil and placebo groups. In the nicorandil group, intravenous nicorandil infusion was started after the induction of anesthesia by a loading dose of 0.1 mg/kg, followed by a continuous infusion of 0.1 mg/kg/h until 2 hours after CPB, then decreased to 0.05 mg/kg/h, and discontinued at the end of surgery. The placebo group received the same volume of saline. Arterial blood was sampled, and serum troponin T (TnT) and CK-MB were measured at the following 4 stages: after the induction of anesthesia (baseline), 2 hours after CPB, the first postoperative day (POD), and the third POD.

Measurements and Main Results: TnT concentrations were similar at baseline and increased with a peak on the first POD in both groups. In the nicorandil group, TnT concentration returned to the baseline value at the third POD, and the time course of TnT showed significantly lower levels (p = 0.012). CK-MB concentrations were similar at baseline, increased and peaked at 2 hours after CPB, and returned to the baseline on the third POD in both groups. There were no significant differences between the groups with respect to the changes in CK-MB concentrations.

Conclusions: The nicorandil group showed lower concentrations of TnT, suggesting that intraoperative administration of nicorandil may provide a degree of myocardial protection in CABG surgery.

Key Words: nicorandil, cardioprotective effect, coronary artery bypass graft surgery