Along with elevated low-density lipoprotein cholesterol (LDL-C), lipoprotein (a) [LP (a)] is an independent atherosclerosis risk factor in middle-aged men. I’m currently preparing a series of thrombophilia modules for the web site, prompting me to “bone up” on LP (a), which has some peculiar characteristics.
LP (a) is a lipoprotein similar to LDL-C but containing a protein, apoA. Lp (a) is a cardiovascular risk factor both connected with and independent of plasma LDL-C levels. The apoA provides a sequence resembling the “kringle” sequences of plasminogen, essential for fibrin binding. Consequently, LP (a), with no active protease domain, competes with plasminogen for fibrin binding sites, slowing fibrinolysis. The effect of LP (a) appears to raise the cardivascular disease risk of middle-aged men, but not elderly men or women. For instance, elevated LP (a) in the presence of elevated total cholesterol raises the risk of a cardiovascular event by an odds ratio of 13.5. It may be that LP (a) should be assayed as a routine part of a lipid profile. Geo.