Lipoprotein(a) is an LDL-like particle with an additional apolipoprotein(a) attached via disulfide bond. Plasma levels are 80-90% genetically determined.
Mechanism — Drives atherogenesis like LDL but also has thrombotic effects via apo(a) similarity to plasminogen. Levels are set at birth and barely change with diet, exercise, or statins.
Lab range — Less than 30 mg/dL (or under 75 nmol/L) is optimal. Greater than 50 mg/dL (greater than 125 nmol/L) is high-risk. Check once in life — value rarely changes.
Caveats — No standard treatment lowers Lp(a) meaningfully. PCSK9 inhibitors drop it 20-30%. Pelacarsen (antisense therapy) is in trials. High Lp(a) means aggressive control of every other modifiable risk factor.