Lipoprotein-associated phospholipase A2 independently predicts the angiographic diagnosis of coronary artery disease and coronary death

Background Whereas C-reactive protein (CRP) is a nonspecific marker of coronary artery disease (CAD) and cardiovascular (CV) events, Lp-PLA(2) may be a nonvariable inflammatory biomarker. We evaluated the independent association of lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) to angiographic CAD and CV events adjusting for standard factors, lipids, and CRP. Methods Lipoprotein-associated phospholipase A2 (PLAC test, diaDexus, Inc, San Francisco, CA) and CRIP were measured from samples donated by consecutive consenting patients (N = 1493) enrolled in the registry of the Intermountain Heart Collaborative Study. All patients underwent coronary angiography (1996-1998) for CAD determination and were followed for 6.7 +/- 0.5 years (range 5.7-7.9 years) for CV events (death [including all-cause, CAD, and non-CAD CV death), myocardial infarction, and cerebrovascular accident). Results Lipoprotein-associated phospholipase A2 weakly correlated with lipids (low-density lipoprotein: r = 0.22, P <.001; high-density lipoprotein: r = -0.13, P <.001), but not CRP (r = 0.03, P =.26). Increasing quartile (Q) of Lp-PLA(2) predicted greater the presence of CAD (vs Q 1) for Q2 (adjusted odds ratio [OR] 1.15, 95% Cl 0.78-1.71, P =.48), for Q3 (OR 1.53, 95% CI 1.02-2.3 1, P =.042), and for Q4 (OR 2.44, 95% CI 1.58-3.79, P <.001), although CRP was also predictive (vs Q1, Q2: OR 1.47, P =.057; Q3: OR 1.93, P.002; Q4: OR 3.43, P <.001). In Cox regression, Lp-PLA(2) predicted CAD death (vs Q1; Q2: adjusted hazard ratio [HR] 1.27, 95% CI 0.58-2.78, P=.55; Q3: HR 2.18, 95% Cl 1.04-4.57, P =.04; Q4: HR 1.73, 95% Cl 0.84-3.61, P =.14). Conclusion Lipoprotein-associated phospholipase A(2) was confirmed to predict the presence of CAD, even among patients undergoing coronary angiography. Uniquely, Lp-PLA(2) predicted the risk of CAD death, but not all-cause death, myocardial infarction, or cerebrovascular accident.