Lp(a) (Lipoprotein(a))

Lipoprotein(a) is an LDL-like particle in which apolipoprotein(a) is covalently linked to apoB-100 via a disulfide bond. Plasma levels are largely (often cited around 70–90%) genetically determined and usually stable across adulthood, although modest changes can occur with menopause, kidney disease, or inflammation. Mendelian randomization at the LPA locus supports a causal role for elevated Lp(a) in myocardial infarction, ischemic stroke, and calcific aortic valve stenosis. Because diet and lifestyle barely influence it, Lp(a) should be measured at least once to stratify lifetime cardiovascular risk. Per EAS 2022 thresholds, rule-in risk levels are >50 mg/dL (>125 nmol/L) and rule-out levels are <30 mg/dL (<75 nmol/L).