Evaluation of Proprotein Convertase Subtilisin/Kexin Type 9 in Patients with Acute Coronary Syndrome: An Observational Study

Background: Proprotein convertase subtilisin kexin/type 9 (PCSK9) plays a pivotal role in low-density lipoprotein cholesterol (LDL-C) metabolism, by decreasing the clearance of LDL-C by promoting the degradation of the LDL receptor and prevents it from recycling to the membrane. Thus, in this study, we aim to assess the serum PCSK9 levels in patients of acute coronary syndrome (ACS) and to evaluate its association with the severity of coronary artery disease based on angiographic findings. Materials and Methods: A cross-sectional case-control study comprised 60 cases and 30 age- and sex-matched healthy controls. Sixty cases were divided into groups depending on the number of vessels involved based on coronary angiogram; Group 1 (single vessel) - 20, Group 2 (double vessel) - 20, and Group 3 (triple vessel) - 20. The serum PCSK9 levels were assessed using the sandwich enzyme-linked immunosorbent assay. Results: The mean concentrations of PCSK9 in single-vessel disease (SVD), double-vessel disease (DVD), and triple-vessel disease (TVD) were 153 mg/ml, 214.5 mg/ml, and 290 mg/ml, respectively, whereas, in controls, it was 133 mg/dl. The serum PCSK9 levels were significantly higher in cases compared to controls (P < 0.0001). There was a significant difference in serum PCSK9 when compared between various groups (controls vs. DVD, controls vs. TVD) (P = < 0.0001), except controls versus SVD which was not statistically significant (P = 0.113). Conclusion: The levels of serum PCSK9 were high in cases compared to healthy controls and were positively associated with the disease severity. Hence, it can be used as a marker in assessing the disease severity in ACS patients with coronary angiography. Keywords: Acute coronary syndrome, low-density lipoprotein cholesterol, proprotein convertase subtilisin/kexin type 9