Reduction of Cardiovascular Risk Using Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitors in Patients With Acute Coronary Syndrome: A Systematic Review

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a hepatic enzyme that regulates blood cholesterol levels by degrading low-density lipoprotein (LDL) receptors from the surface of hepatocytes. Studies have shown that inhibiting this molecule decreases the cardiovascular risk in individuals with atherosclerotic cardiovascular disease (ASCVD) by lowering low-density lipoprotein cholesterol (LDL-C). Two major cardiovascular outcome trials showed that the use of the PCSK9 inhibitors (alirocumab and evolocumab) in patients with recent acute coronary syndrome (ACS) is associated with a lower risk of further cardiovascular (CV) events. Information regarding the use of these monoclonal antibodies for primary prevention has also been reported by these trials. The goal of this systematic review is to describe the mechanism of PCSK9 inhibitors and further discuss their ability to reduce CV risk in high-risk populations. The search strategy was used in a systematic way using PubMed Central, Google Scholar, and ScienceDirect. We included randomized control trials (RCTs), systematic reviews, and narrative reviews in English published in the last five years. Observational studies, case reports, and case studies were excluded. The quality of the studies was evaluated using the Cochrane Collaboration Risk of Bias Tool, Assessment of Multiple Systematic Reviews 2, and Scale for the Assessment of Narrative Review Articles. A total of 10 articles were included in this systematic review. These included an RCT, a systematic review, and eight narrative reviews. Our study suggested that adding PCSK9 inhibitors to background statin therapy for selected patients with high-risk factors demonstrated substantial benefits in reducing overall CV morbidity and mortality after ACS. Multiple studies have demonstrated the short-term safety of low LDL-C levels caused by these drugs. However, long-term safety must be assessed with further studies.