Lipoprotein(a)
What is Lipoprotein(a)?
Lipoprotein (a) or “L-p-little a” [Lp(a)] is a risk factor for heart disease and stroke. Elevated Lp(a) is a genetic condition inherited from a parent.
We frequently talk about two types of cholesterol –
- HDL-cholesterol – (HDL-C): helps the body remove excess cholesterol that may otherwise collect in blood vessels.
- LDL-cholesterol – (LDL-C): at increased blood levels, LDL cholesterol is responsible for building up in arteries and causing blockages that eventually lead to heart attacks, strokes, and more.
However, other types of cholesterol are also found in the blood. One example is Lipoprotein(a), referred to as “Lp(a)”.The level of Lp(a) in our blood is determined at birth and remains relatively constant throughout life. Those with abnormally high levels of Lp(a), with or without elevated levels of LDL-cholesterol, have an increased risk of developing cardiovascular disease (heart attack, stroke, limb ischemia, amputation, abdominal aortic aneurysm, etc.) as an adult. By identifying people at a young age who may be at risk, individuals with abnormally high levels of Lp(a) can take steps to help avoid heart problems in the future.
What are the effects of having abnormally high blood levels of Lp(a)?
Abnormally high levels of Lp(a) may contribute to various major problems with your health:
Atherosclerosis (damage to blood vessels) – Due to the severe and lifelong exposure, those with abnormally high levels of Lp(a) often develop blockages in their arteries. This ultimately causes damage by reducing blood flow to organs, including the heart, brain, and legs. This damage can result in a heart attack, stroke, or limb ischemia at a very early age (for example 40-50 years of age or younger).
Blood clots – When the body is injured, it’s natural tendency is to form a blood clot in order to prevent bleeding. For example, this occurs after an injury or a cut. A similar process occurs when there is injury to a blood vessel; the body forms a blood clot. As the body heals, the clot naturally dissolves, restoring normal blood flow.
In the case of high LDL cholesterol and high Lp(a) levels, blockages can develop in arteries, which cause damage and triggers the body to form a blood clot to “heel” the artery. In addition to causing blockages, high Lp(a) levels can also interfere with the body’s natural mechanism to dissolve blood clots. The combination of blockages in arteries from cholesterol and blood clots in arteries that cannot be dissolved, can lead to reduced blood flow to vital organs, such as the heart and brain, resulting in a heart attack or stroke.
What level of Lp(a) is considered “high” or worrisome?
Lp(a) is measured in milligrams per deciliter (mg/dL) or nanomoles per liter (nmol/L). The National Lipid Association recommends measurement of Lp(a) in nmol/L where possible for greater accuracy. A level higher than 50 mg/dL or 125 nmol/L is considered “high”, although some labs may report Lp(a) as “high” if the level is greater than 30 mg/dL or 75 nmol/L.
What causes levels of Lp(a) to be high?
The amount of Lp(a) in our blood is determined by our body’s genes or “blueprint”. Genes determine everything about us, from the color of our eyes to how our bodies work. The blood level of Lp(a) is determined by each person’s individual genes, which are passed onto you by either your mother or father, whom also has an abnormally high Lp(a). Sometimes both parents may have abnormally high Lp(a).
The elevated Lp(a) trait is passed down when the child receives a copy of the culprit gene causing abnormally high blood levels of Lp(a) from a parent. The presence of 1 affected copy of the gene is all that is needed to cause the level of Lp(a) to be abnormally high. When one parent has an elevated Lp(a), the risk of having an affected child is 50%.Parents with an elevated Lp(a) should have their children tested. Because abnormally high blood levels of Lp(a) is genetic, other family members, such as parents and siblings, can be affected and should also be tested.
How can you tell if someone has abnormally high Lp(a)?
The level of Lp(a) in your blood can be determined with a simple blood test, available in most commercial medical laboratories. It is important to note that it is not necessary to fast before taking this blood test.
- You are concerned about your health or risk of having premature heart disease.
- Have a personal or family history of premature cardiovascular disease, such as a heart attack or stroke, or have a chronic medical condition such as diabetes.
- If someone in your family is known to have an abnormally high blood level of Lp(a).
Because Lp(a) increases risk of premature heart disease but may not cause unique symptoms in children and young adults, many healthcare professionals recommend that everyone have a blood test to determine their Lp(a) level at least once in their life.
Is an abnormally high level of Lp(a) treatable?
Although promising treatments are in development, currently there are no drugs commercially available that specifically lower Lp(a). That being said, there are several things individuals with high Lp(a) levels can do to stay healthy, most importantly is the management of cardiovascular risk factors. For example, lowering levels of LDL cholesterol with proven medications, will also lower an individual’s risk of heart disease. Controlling blood pressure and managing diabetes is important. Furthermore, developing good health habits such as eating a heart-healthy diet, engaging in daily physical activity, avoiding excessive weight gain, and not smoking or quitting smoking, are all vital to good heart health.
Finally, for individuals with an elevated Lp(a) level and a history of heart attack or stroke, consultation with a lipid specialist is appropriate. There are ongoing clinical trials evaluating targeted medications that can lower Lp(a) a considerable amount. Additionally, for select individuals, a blood filtering therapy to remove the Lp(a) cholesterol from the body may be considered (lipid apheresis).
Parents can help children stay healthy by:
- Getting involved:
- Help set realistic goals for a healthy weight, food consumption, and activity levels.
- Talk to your child about healthy eating:
- Pay attention to what your child eats.
- Learn what snack foods your child most often chooses.
- Consider how foods are prepared and which methods of preparation have the most health benefits.
- Encourage appropriate portions of healthy foods, snacks and beverages. Avoid sugar sweetened beverages and encourage fruits and vegetables at all eating occasions.
- Increase daily physical activities for the entire family.
- Avoid smoking or, if you smoke, quit. Teach your child to avoid smoking, or if the child smokes or uses e-cigarettes/vaporizer pens, offer to help them quit.
- Make healthy living a family affair.
- Be a good role model for your child!
What are the treatment options for elevated Lp(a)?
» Lipoprotein Apheresis: a process that removes lipoprotein(a) from the blood, is currently the only FDA-approved therapy.
» Statins: ordinarily the first medication prescribed to lower LDL-C. While statins do not lower Lp(a), statins lower ASCVD risk.
» PCSK9 Inhibitors: For patients requiring more LDL-C lowering after trying statins, PCSK9 inhibitors are an appropriate add-on medication to lower LDL-C. Although not approved by the FDA to treat elevated lipoprotein(a), PSCK9 inhibitors can lower Lp(a) by approximately 20–30%.
» Aspirin: might be of particular benefit in patients with elevated Lp(a), but patients need to discuss the risk-benefit of this option with their clinician. Aspirin may also be an option for children.
Finding a Specialist
Visit the National Lipid Association’s website to access their lipid specialist database: https://www.learnyourlipids.com/find-a-clinician/
Clinical Trials
African American Heart Study- A Real-World Data Study of Atherosclerotic Cardiovascular Risk in African American and Black Participants in the US
Amgen Inc. is sponsoring an observational, case-control study of 2500 African American or Black patients with ASCVD (atherosclerotic cardiovascular disease) and 2500 African American or Black patients without ASCVD. The study was designed to understand the levels of Lipoprotein(a) [Lp(a)] among African Americans and the relationship between Lp(a) and diseases of the heart and arteries. In addition, a key focus of this study is improving the representation of African Americans and Blacks, including patients and physicians, in Amgen clinical studies through community engagement and outreach in collaboration with trusted local partners. The study is currently enrolling patients. For more information please visit: https://abcardio.org/the-african-american-heart-study/