Lipoprotein
Lipoproteins are complex particles in the bloodstream that consist of fat and protein, playing a crucial role in transporting cholesterol and other fats throughout the body. One specific type, lipoprotein(a) or Lp(a), can be an important marker for cardiovascular health. High levels of Lp(a) are linked to an increased risk of heart attack and, in some cases, stroke, making it a significant factor in assessing cardiovascular disease risk. Lp(a) levels are largely determined by genetics and typically remain stable throughout a person’s life.
Testing for Lp(a) is not routinely conducted, as many physicians do not prescribe it due to insurance coverage issues and a lack of established treatment protocols. While diet and exercise do not appear to affect Lp(a) levels, physicians may recommend managing other cardiovascular risk factors, such as high LDL cholesterol and obesity, through lifestyle changes and medications. Current treatment options to lower Lp(a) are limited, with high doses of niacin being one potential avenue, though this may have side effects and its effectiveness in reducing heart attack risk is still uncertain. Research is ongoing to explore new medications that could better manage high Lp(a) levels. Awareness of Lp(a) has gained public attention, particularly through personal stories from individuals affected by its implications for heart health.
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Lipoprotein
Lipoprotein is a particle in the bloodstream made of fat and protein that carries cholesterol, fats, and proteins. A person's genes determine the amount of lipoprotein his or her body creates. If lipoprotein (a), more commonly known as Lp(a), is present in the bloodstream at high levels, it can indicate that the person is at risk of a heart attack or, less commonly, a stroke.
While a person's Lp(a) level is easily determined by a blood test, this test is rarely prescribed by physicians, mainly because it is not covered by many health insurance plans, and physicians are unsure of how to treat the condition if it exists. Diet and exercise do not seem to impact a person's Lp(a) level, which is present at birth and generally remains the same for life.
Physicians may treat the condition with a high dose of the B vitamin niacin. Other times, they may recommend lowering other risk factors of cardiovascular disease (CVD), which include high LDL cholesterol and obesity. In this case, the recommended treatment includes medications to treat high LDL cholesterol and triglyceride levels, healthy eating, exercise, stress management, and, if applicable, cessation of smoking.
Background
Lipoproteins are fatty particles that carry cholesterol and other substances in the bloodstream. People with a high level of lipoprotein (a) are two to three times more likely to develop CVD. Lp(a) consists of LDL cholesterol (bad cholesterol) and the protein apolipoprotein (a).
Lp(a) contributes to the development of atherosclerosis, the leading cause of CVD, by creating plaque, which is made of cholesterol and other waste products, on the walls of arteries. If the plaque is left untreated for years, it can rupture and become stuck in the bloodstream. A blood clot could also form in the artery. Both instances could deprive the heart of oxygen, causing a person to experience a heart attack.
All people have some Lp(a) in their bloodstream. A level less than 30 mg/dL (milligrams per deciliter) is considered normal. A level between 31 and 50 mg/dL is considered high risk of developing CVD, and a level higher than 50 mg/dL indicates a person is at very high risk. According to the Lipoprotein(a) Foundation, about one in five people have an Lp(a) level greater than 50 mg/dL but are not aware of it.
This is mainly because Lp(a) testing is not included in most blood tests for cholesterol and lipids. Many physicians do not prescribe the test, mainly because some health insurance plans do not cover it but also because there is not yet a definitive way to lower Lp(a) levels. They think it is more beneficial to test patients for high LDL cholesterol, which is also a risk factor of CVD but one that can be controlled with medications.
An individual should inquire about the test under the following circumstances: if someone in his or her family has a high Lp(a) level; if a family member has had a heart attack or stroke at an early age (younger than fifty-five for men; younger than sixty-five for women); if the person has had a heart attack or stroke without risk factors such as high LDL cholesterol, obesity, diabetes, or smoking; or if the individual has familial hypercholesterolemia (FH), an inherited condition that causes a person to have very high LDL cholesterol. About 30 percent of people with FH have high Lp(a) levels.
An elevated Lp(a) level is hereditary. If a person is diagnosed with the condition, his or her close blood relatives—including parents, siblings, and children—should also be tested. Because Lp(a) level rarely changes, most people need to be tested only once.
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As of 2017, researchers have not yet discovered any medications to inhibit the production of Lp(a). Prescription formula B vitamin niacin is the only treatment proven to lower Lp(a) levels, but it is not known if lowering levels this way reduces a person's risk of having a heart attack. Such strong doses of niacin also have side effects. Some patients suffer terrible skin itching and hot flashes from taking the vitamin.
Patients who have FH sometimes undergo lipoprotein apheresis, in which their blood is filtered to remove LDL cholesterol and Lp(a) particles. However, the treatment is invasive, expensive, and temporary; it usually must be repeated every one or two weeks.
Researchers are studying the effects of aspirin on high Lp(a) levels and are conducting clinical trials with injectable medications.
Treatment for high Lp(a) often involves lowering all other risk factors that can cause a heart attack or stroke. This includes taking medications to lower LDL, triglycerides, and blood pressure. It also includes managing diabetes in patients who have this disease. Other recommendations include eating foods such as nuts, olive oil, fish, and avocado, which are rich in healthy fats. Other dietary recommendations include eating whole grains and avoiding sugar and trans fats. Patients should aim for at least thirty minutes of exercise per day. They should also limit alcohol consumption and avoid smoking.
The danger of high Lp(a) garnered media attention in 2017 when Bob Harper, the fifty-one-year-old fitness guru and host of the television show The Biggest Loser, suffered a massive heart attack that nearly killed him and left him in a coma for two days. Harper was working out at the time and credits two doctors at the gym with saving his life. He discovered he has high levels of Lp(a) in his bloodstream. Through media interviews, he sought to make people aware of the dangers of high Lp(a) levels and encourage them to undergo testing. Harper's mother died from a heart attack at age seventy.
Bibliography
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"Lipoprotein (a) – Treating the Untreatable." Health Essentials, Cleveland Clinic, 30 Sept. 2011, health.clevelandclinic.org/2011/09/do-you-know-your-cholesterol/. Accessed 20 June 2017.
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"Understanding Inherited High Lipoprotein (a)." Lipoprotein (a) Foundation, www.lipoproteinafoundation.org/?page=UnderstandLpa. Accessed 20 June 2017.