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Risk Factors in Coronary Artery Disease

Discussion: Nonstandard CAD Biochemical Risk Factors

There are some non-standard CAD risk factors such as lipoprotein (a), homocysteine, and LDL subparticles.[12] Table 4 describes the non-standard CAD risk factors.

These risk factors are not part of a typical lipid panel. These tests should be performed when the patient has two or more coronary artery disease risk factors.

Presence of small dense particles of pattern B creates a three-fold CAD risk. The prevalence of these patterns in the general population is approximately 70% for pattern A, 10-15% intermediate and 15-20% pattern B.[15]

The hypothesis regarding the atherosclerotic properties of small dense LDL particles is that as LDL particles enter the arterial vessel walls they become oxidized. Oxidized LDL particles form foam cells during atherogenesis.[12] Oxidized LDL is phagocytized by macrophages. Macrophages become filled with oxidized LDL and form foam cells. These foam cells are observed in early atherosclerotic lesions. The foam cells ultimately lead to formation of atherosclerotic plaque, which can make the affected coronary artery susceptible to abnormal vasoconstriction, which can lead to angina.[12] Studies have shown that the oxidative metabolism of LDL demonstrates a link between hyperlipidemia and development of atherosclerosis.[12,] [14]

Studies have shown that the LDL subclass pattern B is associated with other risk factors like male gender, [16] increased levels of triglycerides and apolipoprotein a and decreased levels of HDL.[14] LDL subclass pattern doesn't have a strong relationship with LDL cholesterol concentration.[14]

It has also been shown that patients with small dense LDL appear to receive the largest benefit from lipid-lowering treatment by converting small dense LDL to more buoyant LDL.[14] This conversion can be achieved by weight loss, diet restriction, and regular exercise. These hygienic measures will lower total cholesterol, triglycerides, and LDL-C, and will increase the size of LDL subparticles and HDL cholesterol levels.