PCSK9 and atherosclerosis: In addition, the ATHEROREMO-IVUS study (The European Collaborative Project on Inflammation and Vascular Wall Remodeling in Atherosclerosis—Intravascular Ultrasound) demonstrated a linear relationship between serum levels of PCSK9 and the fraction or amount of the necrotic core in the non-culprit lesions of patients with acute coronary syndrome, independently of serum levels of LDL-C.