Abstract 747: Pre-Operative Estimation of Endothelial Function and Plasma sCD40L as Well as Vascular Redox State, Predict the Development of Atrial Fibrillation Post-Coronary Artery Bypass Grafting Operation
Background: Atrial fibrillation (AF) is accompanied by endothelial dysfunction, increased oxidative stress and platelet activation (increased circulating sCD40-ligand). Recently, increased myocardial oxidative stress has been associated with an increased risk of new onset AF following coronary artery bypass grafting (CABG). We examined whether preoperative endothelial dysfunction and platelet activation predict the development of post-operative AF.
Methods: We studied 147 patients undergoing CABG. The day before CABG, endothelial function was assessed by estimating flow mediated dilation (FMD) in the brachial artery. Plasma sCD40L was measured by ELISA. Vascular O2- generation in LIMA grafts was measured by using lucigenin chemiluminescence. O2- production associated with eNOS uncoupling was measured as the LNAME-inhibitable component and NADPH-oxidase derived O2- from NADPH-stimulation. Patients were followed up prospectively for 6 weeks.
Results: The “in hospital” newly developed AF was 31.2%. The relative risk for post-operative AF of patients in the highest vs lowest third of plasma sCD40L was 3.83 [95%CI: 1.12–12.94], p=0.03 (Fig a⇓). 3.4% of patients were still in AF at 6 weeks. These patients had higher pre-operative sCD40L (Fig b⇓), lower FMD (Fig c⇓), higher total O2- and higher LNAME-inhibitable O2- (Fig d⇓).
Conclusions: Plasma sCD40L, a measure of platelet activation, is already elevated pre-operatively in those who go on to develop AF post-CABG. Patients with persistent AF at 6 weeks had higher preoperative sCD40L, lower FMD and higher vascular O2- production, mainly due to uncoupled eNOS, at the time of surgery.