Abstracts of Posters Presented at the International Anesthesia Research Society; 72nd Clinical and Scientific Congress; Orlando, FL; March 7-11, 1998: Cardiovascular Anesthesia
Reversible contractile dysfunction may persist for hours or days after cardiopulmonary bypass ("myocardial stunning"). KATP channel agonists produce cardioprotective effects, and enhance functional recovery of stunned myocardium. Nicorandil, a relatively new anti-ischemic drug, activates KATP channels, and exerts cardioprotective effects in dogs. In this study, we evaluated the effects of nicorandil on perioperative hemodynamics in coronary artery bypass graft (CABG) patients.
Following IRB approval and informed consent, 20 patients undergoing elective CABG surgery were studied. Patients were randomly allocated to nicorandil group (n=10) or control group (n=10). Anesthesia was induced with fentanyl and vecuronium, and maintained with morphine and isoflurane. All patients received nitroglycerin i.v. infusion (0.5-1.0[micro sign]g/kg/min) and underwent cardiopulmonary bypass (CPB) at 28[degree sign]C. In nicorandil group, nicorandil i.v. (loading dose 80[micro sign]g/kg, infusion 80[micro sign]g/kg/hr during CPB and 40[micro sign]g/kg/hr after CPB) was started upon initiation of CPB and continued into the postoperative period. Heart rate, arterial pressure, CVP, PCWP, cardiac output, and systemic vascular resistance were recorded. Measurements were made during CPB, and 0,1,3,6,12 hours after the end of surgery. Chi-square test, t-test and ANOVA were used as required. p<0.05 was considered significant.
Demographic data, preoperative cardiac status and medications were similar between the groups. A 80[micro sign]g/kg bolus of nicoradil was not associated with any significant hemodynamic changes. After CPB and in the first 12 hour of postoperative period, control group required epinephrine infusion to maintain hemodynamics more often than nicorandil group (7/10 vs. 0/10, p<0.01). No patients had episodes of postoperative myocardial infarction.
In CABG patients, nicorandil improved perioperative hemodynamics. Further studies are needed to elucidate the mechanism.