Physical Examination
Patients with very elevated LDL-C levels in whom Lp(a) is also high may present with other outward stigmata of dyslipidemia. Visualization of the eye may reveal evidence of severe dyslipidemia with arcus cornea. This arcus can present as unilateral, bilateral, inferior, superior, or mixed and is representative of the buildup of cholesterol that cannot be removed from the body by normal means. Further examination may reveal tendon xanthomas, which are also representative of a genetic cholesterol disorder—in most cases, familial hypercholesterolemia.7
Laboratory Workup
In patients who are known or suspected to be at high risk for CVD, the laboratory workup should include a fasting lipid panel, with Lp(a) and apoB; a comprehensive metabolic profile to establish renal and liver function (as therapeutic interventions utilize these organs for metabolism); and a fasting glucose measurement to rule out occult diabetes, which enhances risk factors. Thyroid function is also assessed, secondary to its deleterious effects on lipid metabolism.
Lp(a) results must be interpreted in the context of ethnicity; significance will vary. For example, both the African-American and Asian populations have been found to have high levels of Lp(a), but these are generally felt to be less atherogenic in African Americans. No major differences have been identified for other populations. It is, however, important to note that those patients with nephropathies and elevated Lp(a) carry a higher risk for coronary artery disease.
Lp(a) levels will remain relatively steady throughout life, negating the need for routine monitoring once a patient’s levels have been established. The exception is postmenopausal women, in whom Lp(a) levels may increase due to changes in estrogen. It is prudent to assess Lp(a) in women both pre- and postmenopause, based on data from the Women’s Health Study.10
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