Clinical significance of plasma free 15-F2t-isoprostane concentration during coronary artery bypasses graft surgery

Abstract

OBJECTIVE: To analyse retrospectively the variation of plasma 15-F2t-isoprostane concentration during cardiac surgery and the relation with early myocardial dysfunction following normothemic cardiac surgery. METHODS: Thirty patients scheduled for coronary artery bypass graft surgery using normothermic cardiopulmonary bypass (CPB) and warm intermittent blood, crystalloid cardioplegia were enrolled. Patients were divided into two groups treated with (group II) or without (group I) positive inotropic drugs. Central venous blood was sampled at baseline, 30 minutes after global myocardial ischemia, 10, 30 and 120 minutes after aortic declamping (reperfusion). Plasma free 15-F2t-isoprostane was measured with enzyme immunoassay (EIA) using a highly specific rabbit 15-F2t-isoprostane antibody. Cardiac index (CI) was monitored intraoperatively and up to 6 hours following surgery. RESULTS: Plasma free 15-F2t-isoprostane increased significantly during ischemia, remained elevating at 10 minutes after reperfusion (P<0.05 vs. baseline) and began to decline at 30 minutes after reperfusion in the whole population. 15-F2t-isoprostane underwent exponential decay and returned to baseline at 30 minutes after reperfusion in group I that did not need any postoperative inotropic support. In contrast, 15-F2t-isoprostane further increased upon reperfusion and remained significantly higher than baseline at 30 minutes after reperfusion (P<0.05) in group II that needed two or more inotropes to maintain CI greater than 2.2 L x min(-1) x m(-2). Postoperative CI was significantly inversely correlated with the percentage change in plasma free 15-F2t-isoprostane concentration from 10 to 30 minutes after reperfusion (r=-0.95, P<0.01). CONCLUSION: It shows a close relationship between free plasma concentrations of 15-F2t-isoprostane and early postoperative cardiac function following coronary artery bypass graft surgery.