Delving Deeper Into Lipids for Cardiovascular Risk Assessment

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Delving Deeper Into Lipids for Cardiovascular Risk Assessment
Delving Deeper Into Lipids for Cardiovascular Risk Assessment

Cardiovascular disease (CVD) continues to be an epidemic in our country, with heart disease the leading cause of death in both men and women. Each year, an estimated 600,000 people die of heart disease in the United States alone.

According to the Centers for Disease Control and Prevention, coronary heart disease (CHD) is the most common type of heart disease affecting our population.

Despite the alarming statistics, we know it is possible to reduce the risk for CVD through lifestyle changes, such as diet and exercise, and with medications, but the first step in doing so is for health care professionals to get a full understanding of a patient's risk.

The most standard procedure for measuring a patient's risk for CVD has been the basic lipid panel (BLP), but new tests and technologies now allow clinicians to look more deeply and differently at a patient's risk factors. Recent clinical evidence has shown limitations of the BLP and benefits of using a more comprehensive analysis.

In one study, for example, comprehensive lipid testing showed that up to 60% of patients may have been misclassified by the BLP as having “normal” cholesterol levels.1

The BLP's primary purpose is to measure LDL cholesterol. However, LDL cholesterol accounts for only 30% of the risk for premature CVD; the remaining 70% is represented by residual risk factors not identified by the BLP. Comprehensive lipid testing has shown the impact that HDL and remnant lipoprotein (RLP) cholesterol levels have on a patient's risk for CHD specifically.

Two meta-analyses presented at the 2014 Annual Meeting of the American College of Cardiology support these conclusions. A team of investigators, including myself, examined findings from two major CV studies: the Framingham Offspring Study and the Jackson Heart Study.

Both included men and women without prevalent CHD and used the Vertical Auto Profile (VAP®) Lipid Panel to measure levels of HDL and its subfractions, as well as RLP. This is a comprehensive lipid profile that assesses cardiometabolic risk factors in three areas: cholesterol, triglycerides and hereditary. [Editor's note: Dr. Toth serves on the medical advisory board of Atherotech Diagnostics Lab, the maker of the VAP Lipid Panel.]

The VAP panel allowed us to take a deeper look at study participants' overall cardiac risk. While previous study findings have shown the link between HDL and CHD, results from the meta-analyses showed that the small HDL subfraction, specifically HDL3, was highly predictive of a patient's risk for CHD, and that elevated RLP cholesterol was associated with increased CHD risk.

What is interesting about these findings is that it has long been assumed in the absence of supportive data that it is the large buoyant HDLs (HDL2) that are atheroprotective, which is incorrect. Elevated RLP cholesterol (the sum of cholesterol in the smallest very-low-density lipoproteins [VLDLs] and intermediate-density lipoproteins [IDLs]) was highly associated with increased CHD risk.

This finding supports the use of non-HDL cholesterol as a target of therapy for reducing risk for CHD, since it includes all atherogenic lipoproteins, including remnants.

Further research is needed to fully understand the impact of these lipoproteins on CVD risk, but these findings are a critical step forward in helping clinicians create personalized, effective treatment plans and improve health outcomes.

Peter P. Toth, MD, PhD, is director of preventive cardiology, CGH Medical Center, Sterling, Illinois, and professor of clinical family and community medicine at University of Illinois, Peoria.

Reference

  1. Martin SS et al. J Am Coll Cardiol. 2013;62(8)732-739.
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