PCSK9 inhibitors in the current management of atherosclerosis

The history of proprotein convertase subtilisin/kexin type 9 (PCSK9) in medical science is fascinating and the evolution of knowledge of its function has resulted in new medications of major importance for the cardiovascular (CV) patient. PCSK9 functions as a negative control or feedback for the cell surface receptors for low-density lipoprotein including its component of cholesterol (LDL-C). The initial and key findings were that different abnormalities of PCSK9 can result in an increase or a decrease of LDL-C because of more or less suppression of cell surface receptors. These observations gave hints and awoke interest that it might be possible to prepare monoclonal antibodies to PCSK9 and decrease its activity, after which there should be more active LDL-C cell receptors. The rest is a fascinating story that currently has resulted in two PCSK9 inhibitors, alirocumab and evolocumab, which, on average, decrease LDL-C approximately 50%. Nevertheless, if there are no contraindications, statins remain the standard of prevention for the high-risk CV patient and this includes both secondary and primary prevention. The new inhibitors are for the patient that does not attain the desired target for LDL-C reduction while taking a maximum statin dose or who does not tolerate any statin dose whatsoever. Atherosclerosis can be considered a metabolic disease and the clinician needs to realize this and think more and more of CV prevention. These inhibitors can contribute to both the stabilization and regression of atherosclerotic plaques and thereby avoid or delay major adverse cardiac events. (United States).

Prevention of Carotid Artery Atherosclerosis: What is the Evidence?

Carotid artery atherosclerosis (CAA) represents a significant form of atherosclerosis with stroke as a major consequence. Whether it is a unique form of atherosclerosis is not established. However, this is not of major clinical relevance as no specific preventive measures over and above the established ones for cardiovascular risk are well established. Major risk factors for CAA are elevated low-density lipoprotein cholesterol (LDL-C), diabetes mellitus, tobacco use, hypertension, and increased inflammation. Identification of CAA prior to a clinical event centers on imaging studies. Studies with magnetic resonance imaging result in the best definition of CAA plaque morphology. Medical measures that result in prevention are especially centered on statins (marked reduction of the LDL-C) and hypertension control. Nonprocedural therapeutic measures to avoid and delay complications involve antiplatelet medications. Benefits from other measures such as increasing high-density lipoprotein cholesterol and increased exercise appear desirable but require more clinical evidence. In conclusion, there are enough evidence-based medicine results to demand intensive medical preventive measures and not just relegate the patient with asymptomatic or symptomatic CAA to decision-making only involving the surgeon and interventionalist.

Defining the Role of PCSK9 Inhibitors in the Treatment of Hyperlipidemia

Statins remain the mainstay of medical cardiovascular risk reduction because of their effectiveness in decreasing low-density lipoprotein cholesterol (LDL-C) as well as some other potentially beneficial effects. The latest US 2013 lipid guidelines essentially recommend only the prescription of a high-dose statin for the high-risk patient. However, both quite old and quite new outcomes evidence, such as reported for ezetimibe, emphasize that LDL-C lowering is, in and of itself, quite important for cardiovascular risk reduction. It appears that the proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors represent a major new contribution to this effort, especially for patients with severe familial hypercholesterolemia, proven clinical cardiovascular disease, statin intolerance, or failure to attain an acceptably low LDL-C goal despite maximum available medical management. Very recent clinical trials have proven overwhelmingly the effectiveness and safety of PCSK9 inhibitors for lowering LDL-C. Both alirocumab and evolocumab have now been approved by the US FDA and there are some initial favorable outcomes data. This review is intended to summarize available evidence and emphasize the possible clinical role of these inhibitors following the approval of alirocumab and evolocumab. Understanding the negative receptor feedback of PCSK9 and the mechanism and beneficial effect of PCSK9 inhibitors for cardiovascular risk reduction is essential for the up-to-date practitioner of cardiovascular medicine. There is every reasonable hope for significant cardiovascular benefit from these new additions to our medical cardiovascular armamentarium.