Blood protein may mean heart disease
DEAR DOCTOR: My blood test results always include levels of HDL and LDL cholesterol, but what about lipoprotein(a)? Don’t high levels triple the risk of a heart attack or stroke at an early age? If so, shouldn’t doctors test for it?
DEAR READER: Lipoprotein(a) is a type of blood protein similar to the low-density lipoprotein (LDL) commonly measured in a cholesterol test. Lipoprotein(a) boosts the blood’s clotting ability, which could potentially aid wound healing and repair of tissues, though no specific need for lipoprotein(a) has been found. The big concern with lipoprotein(a) is its potential to encourage clot formation within the arteries, raising the risk of heart attacks and strokes.
As for why some people have higher lipoprotein(a) levels than others, the answer is in our genes. Variations of lipoprotein(a) levels appear to be related to a part of a gene called apo(a). Two different variations in this gene can cause elevation of lipoprotein(a).
If you have a family history of early heart disease, your doctor should consider checking your lipoprotein(a) level, especially if you have no other risk factors. People who
have had a heart attack without any other risk factors also should have their levels checked.
As for lowering the lipoprotein(a) level, niacin can do this at high doses (2 to 4 grams per day), as can cholesterol-lowering PCSK9 inhibitors. Note, however, that no studies thus far have assessed the benefits of doing so.
Instead, people with very high levels of lipoprotein(a) may find greater benefit in significantly lowering their overall cholesterol with statins. Statins won’t lower the lipoprotein(a) level itself, but they provide greater health-related bang for the buck. Lastly, because elevated lipoprotein(a) levels increase the risk of clot formation in the arteries, people at high risk may also find it prudent to take aspirin as a blood thinner.
Robert Ashley, M.D., is an internist and assistant professor of medicine at the University of California, Los Angeles.
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