Lipoprotein(A) As a Risk Factor for Ischemic Heart Disease: Metaanalysis of Prospective Studies (Lipids and Lipoproteins‪)‬

The role of lipoprotein(a) [Lp(a)] as a risk factor for ischemic heart disease (IHD) has received considerable attention in recent years. Lp(a) resembles the LDL particle in structure. Apolipoprotein B is the major apolipoprotein associated with LDL; in Lp(a), however, an additional apolipoprotein, apolipoprotein(a), is bound covalently to apolipoprotein B (1). The physiology and function of Lp(a) are still poorly understood, but the apolipoprotein(a) molecule demonstrates high sequence homology (75-90%) with plasminogen (2). This suggests that Lp(a) might contribute to the thrombotic, as well as to the atherogenic, aspects of IHD (3). Retrospective studies, in which subjects with existing disease were compared with matched controls, have consistently shown an important association between increased concentrations of Lp(a) and IHD. Subjects in these studies have included survivors of myocardial infarction (4, 5), patients with symptoms of angina (6), and those with atherosclerosis confirmed by B-mode ultrasonography (7) or coronary angiography (8, 9). An association has also been demonstrated between Lp(a) concentrations and the severity of atherosclerosis, as quantitated by angiography (10).