Balaji Tamarappoo, MD
Balaji Tamarappoo, MD, is the Associate Professor, Internal Medicine, University of Arizona College of Medicine—Phoenix.
It’s almost certain that a blood test for lipoprotein (a) will soon be recommended for everybody.
Lipoprotein (a) [Lp (a)] is a blood lipid disorder that affects one out of four people. Some affected people have a 25 percent higher risk of a heart attack or stroke. Lp (a) was discovered in 1963. Over the years, research has found that people with high levels of Lp (a) have a significantly higher risk of cardiovascular diseases (CVD) that include heart attack, stroke, and aortic stenosis (disease of the valve that regulates blood flow out of the heart).
Most people inherit the gene for Lp (a), so there is no way to prevent it. There has also been no way to treat it. For those reasons, Lp (a) has remained in the shadows of cholesterol and blood lipid management. However, due to an increasing amount of evidence for how dangerous this condition is and the coming availability of new medications that may finally be able to treat it, Lp (a) is about to come out of the closet and become a big deal.
Lp (a) is a type of lipoprotein, a fat and protein molecule that carries cholesterol in the blood. Cholesterol is an important building block for cells and cell walls, but too much LDL cholesterol (the bad cholesterol) can get stuck in the arteries that supply your heart and brain. Fat, cholesterol, and other substances deposited in an artery can form into a plaque that starts to block blood flow. This condition is called atherosclerosis.
Lp (a) carries an extra protein called Apo (a) that makes it worse than ordinary LDL. Lp (a) causes more inflammation and interferes with the body’s ability to break down a blood clot. A clot added to an atherosclerotic plaque can cause an obstruction that leads to a heart attack or stroke.
Levels of Lp (a) are measured in milligrams per deciliter (mg/dL) and can range from one to 1,000. The higher the number, the higher the risk. According to a 2023 update from the American College of Cardiology (ACC), less than 30 mg/dL is considered safe, 30 to 50 is intermediate, and above 50 is high risk.
A study of Lp (a) risk was published in 2024 by researchers from Brigham and Women’s and Mass General Hospital in the Journal of the American College of Cardiology. The study followed more than 16,000 patients with a diagnosis of Lp (a), for about 12 years. The average age at the start was about 60. They matched levels of Lp (a) to the risk of a major CVD event, including nonfatal heart attacks and strokes, needing a procedure like a stent to restore heart blood flow (reperfusion), and death from cardiovascular disease.
About 10,000 patients in the study already had a history of CVD, without a major CVD event at the start. The rest of the patients had no documented history of CVD. Both patient groups had increasing CVD events with an increase in Lp (a) levels. Patients with CVD and Lp (a) levels in the high-risk range were 21 percent more likely to experience an event than those in the safe range. For patients not diagnosed with CVD, the risk of an event at the highest levels of Lp (a) was almost double the risk of patients in the low range. For all patients in the study, between 5 and 6 percent had a heart attack, 8 to 9 percent had a stroke or reperfusion procedure, and just under 15 percent died of CVD during the study period.
The researchers concluded that the availability of effective drugs approved to treat Lp (a) and the growing evidence of elevated Lp (a) risk should prompt the U.S. guidelines to start recommending universal screening for Lp (a). A one-time blood test for everyone over age 5 is already recommended in Europe and Canada.
There has been no treatment approved to lower Lp (a), but that should be changing soon. For now, the best way to manage Lp (a) risk is to concentrate on other risk factors, called manageable risk factors. These include exercise, a healthy weight, a heart-healthy diet, not smoking, and avoiding or using alcohol only in moderation. Statins can lower bad LDL and increase good HDL. Even though they do not lower Lp (a), they may still reduce the risk of a CV event.
The first new drug that will lower Lp (a) is in the final stages of clinical trials. It blocks production of Lp (a) in the liver. Called pelacarsen, it is given as a once-monthly injection. Clinical trials suggest it can reduce Lp (a) by up to 80 percent. Approval by the FDA may come by next year. Like all new drugs, the price is expected to be high at first, but insurance providers will probably start by covering treatment for those at highest risk. There are also more new drugs in the clinical trial pipeline.
In the near future, universal screening will allow doctors to identify those at risk from elevated Lp (a) and order a heart imaging study (coronary calcium scan) to see if they already have some atherosclerosis. Treatment with lifestyle changes and the new Lp (a) drug can then be targeted at preventing atherosclerosis or managing it aggressively to prevent a heart attack or stroke.
Anyone can ask for a Lp (a) blood test right now. There are some risk factors for Lp (a) that should trigger a discussion about Lp (a) testing with your health-care provider. These conditions include having:
