Importance
While statins remain the foundation for treating high cholesterol in order to reduce cardiovascular risk, new evidence has lead to important revisions in the American Heart Association’s recommendations for treatment of hypercholesterolemia in patients at very high cardiovascular risk (secondary prevention) with the addition of specific nonstatin agents. We will briefly review the AHA 2013 guideline recommendations, the relevant new information, and the updated AHA recommendations.
Dr. Neil Skolnik
American Heart Association 2013 guidelines
The 2013 American College of Cardiology/AHA cholesterol guidelines recommend either high- or moderate-intensity statin therapy for patients in the four statin benefit groups:
1. Adult patients older than 21 years of age with clinical atherosclerotic cardiovascular disease (ASCVD).
2. Adults older than 21 years of age with low-density lipoprotein cholesterol (LDL-C) above 190 mg/dL.
3. Adults aged 40-75 years without ASCVD but with diabetes and with LDL-C 70-189 mg/dL.
4. Adults aged 40-75 years without either ASCVD or diabetes, with LDL-C 70-189 mg/dL and an estimated 10-year risk for ASCVD of over 7.5% as determined by the Pooled Cohort Equations.
At the time of the 2013 guidelines, there was little evidence to recommend the use of medications other than statins.
Recent evidence
The IMPROVE-IT trial1 was a double-blind, randomized trial involving 18,144 men and women who were older than 50 years and hospitalized for an acute coronary syndrome within the preceding 10 days. They were randomized to either simvastatin plus ezetimibe or simvastatin plus placebo. The primary endpoints were a composite of death from cardiovascular disease, a major coronary event (nonfatal MI, unstable angina requiring admission, or coronary revascularization), or nonfatal stroke. At 1 year, the mean LDL was 69.9 mg/dL in the simvastatin-monotherapy group and 53.2 mg/dL in the simvastatin-ezetimibe group (P under .001), representing a 24% decrease in LDL between the two groups. The rate of the primary endpoints was significantly lower in the simvastatin plus ezetimibe group with a hazard ratio of 0.936 (P = .016). The risk of MI was significantly decreased with an HR of 0.87 (P = .002), and the risk of ischemic stroke significantly decreased with an HR of 0.79 (P = .008). Prespecified safety endpoints showed no significant difference between the two groups.
The FOURIER trial2 examined the PCSK-9 inhibitor, evolocumab. FOURIER was a randomized, double-blind, placebo-controlled study involving 27,564 patients with atherosclerotic cardiovascular disease and LDL levels of 70 mg/dL or higher who were receiving statin therapy (at least atorvastatin 20 mg or equivalent with/without ezetimibe). Patients were between 45 and 80 years old with a history of history of MI, nonhemorrhagic stroke, or symptomatic peripheral artery disease. Patients were randomized to receive subcutaneous injections of evolocumab or matching placebo. The primary endpoints were similar to that of IMPROVE-IT: a composite of cardiovascular death, myocardial infarction, stroke, unstable angina hospitalization, and coronary revascularization. The median LDL on entry was 92 mg/dL for both groups. At 48 weeks, the evolocumab group showed a 59% decrease in LDL, compared with placebo, with a decrease in median LDL from 92 mg/dL to 30 mg/dL. The primary endpoint occurred in 9.8% of the evolocumab group and 11.3% in the placebo group for a hazard ratio of 0.85 (P less than .001) representing a total risk reduction of 13.2%. The risk of MI or stroke and need for revascularization were significantly lower values in the evolocumab group, compared with placebo. Cardiovascular death did not show significant changes. There was no significant difference in rate of serious events.
The ODYSSEY trial3 reported on another PCSK-9 inhibitor, alirocumab, in a randomized, double-blind, placebo-controlled trial involving 18,924 patients who had an ACS in the prior 12 months. At the median follow-up (2.8 years), the LDL of the alirocumab group was 53.3 mg/dL, compared with 101.4 mg/dL in the placebo group. The primary endpoints for cardiovascular risks were similar to those in the FOURIER trial: a risk of 9.5% in the alirocumab group and 11.1% in the placebo group for a total risk reduction of 14.4%. This suggests the class of PCSK-9 inhibitors have a strong correlation with reducing LDL levels 54%-59% and reducing major cardiac adverse events by 13%-15%.