Abstract 2890: Nesiritide Enhances Myocardial Protection during the Revascularization of Acutely Ischemic Myocardium

Abstract

Nesiritide, a recombinant human B-type natriuretic peptide, has been used in conjunction with inotropic agents in the postoperative management of low cardiac output and pulmonary hypertension. However, its effects on intraoperative myocardial protection are unknown. This study was therefore undertaken to determine whether Nesiritide could enhance myocardial protection when given intraoperatively in a porcine model simulating urgent CABG surgery. Twenty pigs underwent occlusion of the second and third diagonal coronary arteries using snares for 90 minutes followed by 45 minutes of antegrade, cold blood cardioplegic arrest and 180 minutes of reperfusion on cardiopulmonary bypass(CPB) during which time the snares were released. Ten animals received an IV bolus of Nesiritide(2ug/kg) at the initiation of coronary occlusion followed by a 0.01ug/kg/min IV infusion during coronary occlusion, cardioplegic arrest, and reperfusion on CPB. Ten other animals underwent the same protocal without Nesiritide(placebo). Infarct size was assessed by the area of necrosis/area of risk(AN/AR) using histochemical staining, endothelial function by the % change in coronary vasodilation using ring chamber methodology, and lung edema using % change in wet/dry weights. The data is expressed as the mean+/− standard deviation. Nesiritide treated hearts had significantly decreased infarct size, better preservation of endothelial function, and less lung edema. In a porcine model of acute coronary occlusion simulating urgent CABG surgery, the intraoperative infusion of Nesiritide limited myocardial damage. These data suggest that IV Nesiritide infusions may afford increased myocardial protection when administered intraoperatively during the revascularization of acutely ischemic myocardium. RESULTS