Proprotein convertase subtilisin-kexin type 9 as a biomarker for the severity of coronary artery disease

Aim. To evaluate the relation of proprotein convertase subtilisin-kexin type 9 (PCSK9) levels to coronary artery disease (CAD). Methods. A total of 1031 consecutive individuals (552 CAD and 479 controls) were prospectively enrolled. The associations of plasma PCSK9 levels with the incidence and severity of CAD were investigated. Further, mediator analysis was performed to detect the potential mechanisms of the associations. Results. No difference in PCSK9 levels between CAD patients and controls was detected (median 224.75 versus 224.64 ng/mL, P > 0.05). However, the CAD group had higher PCSK9 levels than the control group when adjusting for the confounding factors (228.03 +/- 1.01 versus 219.28 +/- 1.02 ng/mL, P = 0.019). PCSK9 levels were also associated with the severity of CAD assessed by the Gensini score (GS) system (P for trend < 0.05). Logistic regression analysis showed that PCSK9 levels were associated with an increased CAD risk (OR 3.296 and 5.130 for the incidence and severity, respectively). Importantly, mediator analysis indicated that the effects of PCSK9 levels on CAD were mediated by lipid (around 20%) and inflammation (around 15%). Conclusions. PCSK9 levels were positively associated with the severity of CAD; the relatively important mechanisms including lipid and inflammation pathways were partly involved in this association.