What is Lipoprotein(a)
Lipoprotein (a), also known as lipoprotein “little a” is an important genetic risk for heart disease and stroke.
Lipoprotein(a) particles carry cholesterol in the blood just as LDL is a particle that carries cholesterol. High Lp(a) levels are associated with higher risk for heart attacks, aortic stenosis and stroke.
One in 5 people (20%) have high levels of Lp(a) -- greater than 50 mg/dL or 500 mg/L) – from birth based on inheriting genetic factors from their parents.
Difference between LDL-C and Lp(a)
What is a normal Lp(a) level and what role does Lp(a) play in high cholesterol?
Lp(a) levels are inherited and not associated with one’s diet, exercise, or obesity.
Measurement of Lp (a) has not been standardized the way measurement of LDL has. This means that there is more than one way to report Lp(a) levels. When your healthcare provider (HCP) reviews your Lp(a) result with you it is important to know which measurement is used for your results: mg/dL or nmol/L.
- An Lp(a) level > 50 mg/dL (100 nmol/L) increases the risk of heart attack and stroke.
One thing that is a little tricky, but important to know, is that because Lp(a) is made up of LDL-C and apolipoprotein (a), your Lp(a) actually contributes to your LDL-C level (bad cholesterol). A rough rule of thumb to figure out how much of your LDL-C is actually Lp(a) is to divide your Lp(a) (in mg/dL) by 3. So, for example, if your Lp(a) is 90 mg/dL it is contributing 30 mg/dL to your LDL-C level.
Does having a high Lp(a) make me at increased risk for heart disease?
Lp(a) is an independent risk factor for cardiovascular disease. Elevated levels of Lp(a) collect in the arteries, gradually narrowing the arteries and limiting blood supply to the heart, brain, kidneys and legs.
Lp(a) is the combination of an LDL like particle and apolipoprotein (a). Like LDL, Lp(a) can clog arteries with plaque. Apolipoprotein (a) gives Lp(a) an additional quality, it seems to behave like a clotting factor. The combination of, increased plaque and increased clotting, can increase the risk of heart attacks and stroke.
How is Lp(a) inherited?
The amount of Lp(a) your body makes is inherited from your parents and is determined by the genes they passed on to you when you were born. A person’s Lp(a) reaches his or her adult level by around age 5 and remains stable thereafter. The only exceptions to this include menopause and acute illness, Lp(a) increases in both these settings. The increase during menopause is due to declining levels of estrogen.
Lp(a) and Children
Elevated Lp(a) has been linked to childhood stroke. However, strokes in children are rare and have different causes than in adults where stroke is typically related to high blood pressure, elevated cholesterol, smoking, diabetes, and other long-standing cardiac conditions.
Depending on the underlying cause of stroke in a child, current pediatric guidelines may suggest the use of blood thinners and antiplatelet medications. In some cases, apheresis is used to lower Lp(a) in these children. Treatment decisions in these settings should be made by experienced clinicians.
Treating High Lipoprotein(a)
Learn about current and new treatments on the horizon.
Kronnenberg F., Uterman G. Lipoprotein(a): resurrected by genetics. Internal Medicine J, 2013, 273;6-30
Nordestgaard F., Chapman J, et al. Lipoprotein(a) as a cardiovascular risk factor current status. European Heart J. 2010;31,2844-2853
Mortensen M, MD, PHD, Afzal S, MD, PHD et al. Primary Prevention with Statins. ACC/AHA Risk-Based Approach Versus Trial-Based Approaches to Guide Statin Therapy.
image 1.1 courtesy of Amgen
Page reviewed by Dr. Mary McGowan