The Relationship between the Plasma PCSK9 Levels and Platelet Indices in Patients with Stable Coronary Artery Disease

Aim: Recent studies have shown that platelet indices are linked to metabolic and cardiovascular diseases, in addition to being markers of hemostasis. These studies suggested that they could be modified by various biomolecules, including lipids. Proprotein convertase subtilisin/kexin type 9 (PCSK9), a newly-identified member, plays a key role in lipid metabolism and atherosclerosis. Therefore, we evaluated the relationship between the plasma PCSK9 level and platelet indices. Methods: In this cross-sectional study, a total of 330 consecutive, stable coronary artery disease (CAD) patients were enrolled at our center between October 2012 and April 2014. The baseline clinical characteristics were collected, and the plasma PCSK9 levels were determined using an ELISA. The associations between PCSK9 and the platelet indices were investigated. Results: The plasma PCSK9 levels were positively correlated with the platelet (PLT) count and plateletcrit (PCT) (r=0.218, p<0.001; r=0.250, p<0.001; respectively), while no correlation of PCSK9 with either the mean platelet volume (MPV) or platelet distribution width (PDW) was found. The association of PCSK9 with the PLT and PCT remained after adjusting for cardiometabolic risk factors (beta=0.300, p<0.001; beta=0.269, p<0.01; respectively), but the latter disappeared when further adjusted for inflammatory markers (beta=0.212, p<0.05; beta=0.151, p=NS). Additionally, a correlation analysis performed according to the number of diseased vessels showed that PCSK9 was related to the PLT and PCT in patients with single-, two-or multi-vessel disease, with a particularly strong correlation with two-vessel disease. Conclusions: The plasma PCSK9 levels are positively associated with the PLT count in CAD patients, suggesting a potential link between PCSK9 and platelets that may be involved in atherosclerosis and metabolic disorders.