Lipoprotein-associated phospholipase A2 is elevated in patients with severe aortic valve stenosis without clinically overt atherosclerosis

Background: Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) is an inflammatory mediator involved in atherosclerosis. Since aortic valve stenosis (AVS) is regarded as an atherosclerosis-like inflammatory disease, we sought to investigate whether AVS is associated with elevated Lp-PLA(2). Methods: Plasma Lp-PLA(2) levels were determined in 48 consecutive patients with severe AVS without atherosclerotic vascular disease and compared with the values obtained in 48 controls matched for age, sex and cardiovascular risk factors. Results: Lp-PLA(2) was higher in AVS than in controls (242.3 +/- 50.4 vs. 151.9 +/- 28.1 ng/mL, p < 0.0001). Lp-PLA(2) correlated inversely with aortic valve area (AVA) (r=-0.53; p=0.0001) and positively with mean pressure gradient (PG) (r=0.32; p=0.029). In multivariable analysis C-reactive protein (CRP) (OR=1.42; 95 % CI 0.95-2.1; p=0.09) and AVA (OR=0.003; 95 % CI 0.00004-0.23; p<0.01) were independently associated with Lp-PLA(2) above a mean of 242 ng/mL. After adjustment for CRP, AVA was the only independent predictor of Lp-PLA(2) in AVS patients (p<0.001). Conclusions: This study is the first to show that AVS is characterized by increased plasma Lp-PLA(2) levels associated with the severity of AVS, which suggests active involvement of Lp-PLA(2) in the pathogenesis of AVS.