Reducing Cholesterol to Prevent Coronary Heart Disease

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Abstract

Coronary heart disease (CHD) remains the number one killer of men and women in the US, despite major advances in interventional technologies for the treatment of coronary artery disease.The recognition and treatment of coronary risk factors such as high cholesterol levels, hypertension, smoking, and diabetes has made a positive impact on CHD morbidity and mortality. The most successful treatment has targeted lowering low-density lipoprotein (LDL) cholesterol with the statin class of medications. Recent studies have extended the boundaries of treatment to different risk groups and are reporting significant reductions in coronary events.

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The Framingham Heart Study documented that cholesterol levels correlated with survival.1 The Multiple Risk Factor Intervention Trial2 showed that an increased death rate was evident at cholesterol levels above 200mg/dl and established the relationship between cholesterol levels and mortality.A meta-analysis of over 40 cholesterol treatment trials indicated that a 10% reduction in serum cholesterol translates into a 15% reduction in CHD mortality and an 11% reduction in total mortality.3 This relationship applies to most cholesterol-reducing modalities including diet and surgical approaches.

National Cholesterol Education Program
The National Cholesterol Education Program (NCEP) highlighted the benefits of cholesterol lowering and recommended that a reduction in LDL cholesterol should be the primary target of therapy for at-risk individuals.4 A first step in management is to assess a patient™s risk status. Individuals can be classified into lowrisk (<10% ten-year risk of a coronary event), intermediate-risk (10% to 20% ten-year risk) or highrisk (>20% ten-year risk) for a major coronary event.The high-risk category includes patients with established CHD as well as non-CHD patients that carry the same risk for major coronary events as CHD patients. This includes patients with diabetes mellitus and patients with other clinical forms of atherosclerosis (referred to as CHD-risk equivalents). LDL cholesterol treatment goals are set based on the risk category (see Table 1).

Table 1: Categories of Risk that Modify LDL Cholesterol Goals (adapted from 4)

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Recently, the concepts of the vulnerable plaque and the vulnerable patient have been emphasized.Acute coronary syndromes most commonly occur when a lipid-laden plaque ruptures causing thrombus formation and disruption of blood flow in the artery. Plaques that are vulnerable tend to have active inflammation and poorly formed fibrous caps that are prone to disruption. Lipidlowering therapy can decrease inflammation and allow healing and thickening of the fibrous cap making the plaque less likely to rupture. Vulnerable patients are patients with multiple risk factors and multiple plaques making plaque rupture a more likely event. The measurement of inflammatory markers in the serum such as high sensitivity C-reactive protein (hsCRP) may be useful in identifying the vulnerable patient.These patients may benefit from more aggressive lipid-lowering therapy. For example, an intermediate-risk patient with elevated inflammatory markers may be treated to the high-risk NCEP goals or lower./>/>

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References

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