ABSTRACT
Lipoprotein(a) Lipoprotein(a) (Lp(a)) is a low-density lipoprotein (LDL) particle with an apolipoprotein apo(a) attached. Apo(a) is linked to LDL by a disulfide bond with a repeating kringle structure (named for a looped Scandinavian pastry) (Figure 7.1).1 This structure has significant homology to plasminogen, and the enhanced coronary heart disease (CHD) risk associated with Lp(a) is reportedly due to the inhibiting effects of this lipoprotein particle on plasminogen activation, leading to enhanced thrombosis. Lp(a) may also increase the atherogenicity of LDL.2-4 The majority of observational trials (10 of 15) support the association of Lp(a) with enhanced cardiovascular risk. Every 30 mg per dL increase in Lp(a) approximately doubles the risk of CHD. The distribution of Lp(a) levels in the population is different from the bell-shaped curve for serum cholesterol, but the majority of Americans have low levels (less than 10 mg/dl), with a small percentage having greater than 30 mg/dl.5 Elevated Lp(a) is more common in the Asian Indian and Turkish populations.
