Results from epidemiological studies have indicated that high plasma levels of lipoprotein (a) are an independent risk factor in the early development of arteriosclerosis. In addition to these data, biochemical and immunohistochemical studies have demonstrated the presence of apolipoprotein (a) in vessel wall tissue. The mechanism for the atherogenicity of lipoprotein (a) has been studied in more detail recently and evidence obtained that apolipoprotein (a) interferes with fibrinolysis.