Lipoprotein-associated phospholipase A(2) is an independent marker for coronary endothelial dysfunction in humans

Objective - The purpose of the current study was to determine whether lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) is associated with coronary endothelial dysfunction and is a predictor of endothelial dysfunction in humans. Methods and Results - Patients (172) with no significant coronary artery disease (< 30% stenosis) undergoing assessment of coronary endothelial function were studied. Endothelial function was assessed by the change in coronary blood flow and coronary artery diameter in response to intracoronary acetylcholine. Plasma concentrations of Lp-PLA(2) were measured, and patients were divided into tertiles. Patients in tertiles 2 and 3 had a significantly lower change in coronary blood flow (63.8 +/- 73.2 and 32.0 +/- 71.7 versus 78.4 +/- 73.2%; P < 0.001) and greater epicardial coronary artery vasoconstriction (-14.1 +/- 14.7 and -23.3 +/- 25.1 versus -9.5 +/- 15.2% mean diameter change; P < 0.001) in response to acetylcholine. Patients with coronary endothelial dysfunction had significantly higher serum concentrations of Lp-PLA(2) than those with normal endothelial function (246.2 +/- 71.6 versus 209 +/- 56.7 ng/mL; P < 0.001). The odds ratio for coronary endothelial dysfunction in patients with Lp-PLA(2) in the highest tertile was 3.3 (95% CI, 1.6 to 6.6). Conclusions - Lp-PLA(2) is independently associated with coronary artery endothelial dysfunction and is a strong predictor of endothelial dysfunction in humans.