lipoprotein(a)

Lipoprotein(a) is a special cholesterol-carrying particle, similar to LDL but with an extra protein tail attached. Its blood level is set mostly by the genes you inherit and changes little over a lifetime, so it is essentially a fixed, built-in risk factor handed down in families.

The particle resembles LDL but carries an additional component called apolipoprotein(a) that also interferes with the breakdown of blood clots. Through both depositing cholesterol in artery walls and a tendency to promote clotting, a high lipoprotein(a) independently raises the risk of heart attack, stroke, and a stiffening narrowing of the aortic valve.

Because it is largely genetic, standard cholesterol drugs and lifestyle changes do little to lower it, though they remain important for managing overall risk. A once-in-a-lifetime measurement can identify people who carry this hidden risk, especially those with early or strong family histories of heart disease, and targeted lowering therapies are under active study.