Why the Tiny Lp(a) Molecule is Big News for Heart Disease.
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Doctors have known for decades that a molecule called lipoprotein(a)—lipoprotein little a or Lp(a)—is closely related to the risk of having a heart attack or heart valve disease. This molecule runs in families, and people with high Lp(a) levels have higher rates of cardiovascular events, such as heart attack, aortic valve surgery, and possibly stroke. 

For years, scientists have sought an effective treatment to lower Lp(a) with the hope that this would also lower cardiovascular risk. Statins, diet, and exercise don't reduce Lp(a), and vitamins that modestly reduce Lp(a) don't seem to reduce risk. Cholesterol-lowering statins and PCSK9 inhibitors reduce heart attack and stroke risk by lowering LDL. So we work with patients with high Lp(a) to lower their LDL. 

But all that is about to change. In 2025, researchers will complete LP(a) HORIZON, a study that may lead to new class of drugs that appears to be very effective at reducing Lp(a). While data from this study are not yet available, we’re optimistic that research into this medication will prove that lowering Lp(a) also lowers the risk of cardiovascular events.

About 1 in 5 people in the U.S. have elevated Lp(a) levels, making it more common than diabetes. Being able to reduce this type of cholesterol at the molecular level could put a significant dent in heart disease complications.

Until then, we recommend talking with your doctor about Lp(a) and how it may influence your personal risk of heart disease

How high Lp(a) levels can harm heart health.

Lipoproteins are made in the liver. They carry proteins and fats in the bloodstream, as well as the low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterols doctors commonly check when they measure your cholesterol levels. 

Molecule size matters when it comes to heart risks associated with Lp(a). Molecule size is determined by your genes, just like familial hypercholesterolemia (genetic high cholesterol), which can raise your LDL regardless of your lifestyle choices. 

Larger Lp(a) molecules are usually few in number. People with smaller and more Lp(a) may be at increased risk of heart disease. Small Lp(a) molecules can cross the walls of blood vessels more easily, resulting in:

  • LDL buildup in your blood vessels, causing plaques that can break free, decrease blood flow, and cause a heart attack or stroke.
  • Increased clotting, which can block blood vessels.
  • More inflammation, which makes it more likely plaques will rupture.

The future of Lp(a) treatment.

In preventive cardiology, we have some effective medications. There are statins, a class of cholesterol-lowering medications. Aspirin is helpful, but only safe for some patients. Newer drugs like Repatha and Praluent (both PCSK9 inhibitors) can reduce your Lp(a) somewhat while lowering cholesterol.

In 2025, we expect completion of the phase 3
Lp(a) HORIZON study, which is examining whether the medication Pelacarsen can help lower Lp(a) and reduce the risk of major cardiovascular events like heart attack and stroke. If effective, the medication will be a very exciting advancement. Similar studies are expected in 2026 and 2027.

If you have a family history of heart disease, talk with your doctor about Lp(a) screening. Because Lp(a) is genetic, you only need a simple, one-time blood test. If your Lp(a) levels are high, you may require treatment for high LDL, which can decrease your risk of having a heart attack.

The future is promising, and there are treatment options that can help today. Lp(a) is just one biomarker among more than 400 that can impact your individual level of risk. While we work together to build a future of personalized medicine, my colleagues and I at MedStar Washington Hospital Center can work with you to reduce your risk of heart disease today.

Take control of your heart health.

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