An important part of assessing heart health is a cholesterol screening, which is part of your annual physical. High cholesterol (specifically certain blood levels of cholesterol, like LDL) has been linked to conditions such as heart attack and stroke. The World Health Organization (WHO) reported that cardiovascular disease was responsible for approximately 32 percent of global deaths in 2019.
What most people don’t realize is that thrombosis, the medical term for the formation of blood clots, is often the underlying cause for both heart attack and stroke. A blood clot is a partially solid collection of blood that can form in your arteries or veins, blocking blood flow to that area, according to the Cleveland Clinic. Depending on where the clot forms, this can lead to a heart attack, stroke, deep vein thrombosis, or pulmonary embolism.
How High Cholesterol Can Cause Blood Clots
High cholesterol levels are linked to blood clot formation in a couple of ways. High specific cholesterol levels are a major risk factor for atherosclerosis, which is a buildup of fatty plaques on and inside the walls of the arteries. According to the American Heart Association (AHA), plaque is made up of cholesterol, fats, your cells’ waste products, calcium, and fibrin (which causes blood clotting).
As fatty plaques continue to grow, they can narrow the arteries and limit blood supply to your vital organs. This can cause symptoms, such as angina, which is caused by reduced blood supply to the heart, and is often experienced as chest pain during exertion. Reduced blood supply to the legs can also lead to leg pain during exercise, a condition known as intermittent claudication; the condition is usually a symptom of peripheral artery disease, a narrowing of arteries in the limbs, according to the Mayo Clinic.
In terms of the connection between high cholesterol and the formation of blood clots, the danger is if one of these plaques rupture. “When you have high levels of cholesterol, those cholesterol particles can get in the walls of the artery, causing damage,” says Nada Shaban, MD, a cardiologist at Rush University Medical Center.
Plaque formation can cause the artery walls to bulge out, weakening them in the process. There is growing evidence in the research community that while elevations in certain cholesterol levels are associated with increased risk of blood clot formation, that a root cause may be chronic inflammation (from unhealthy lifestyle factors and behaviors around diet, inactivity, stress, among others).
If one of these plaques tear or rupture, this exposes the fatty material inside to blood, which triggers blood clot formation. The clot can rapidly grow in size until it blocks the artery and prevents normal blood flow.
Blockage of heart arteries leads to a heart attack, whereas blockage of brain arteries leads to a stroke.
There is also additional evidence to suggest that high cholesterol can also lead to the formation of blood clots in veins, which is called venous thromboembolism (VTE). Depending on where the clot forms, this can lead to either deep vein thrombosis or pulmonary embolism. According to one study, high LDL cholesterol levels were identified as a risk factor for developing VTE.
How Can You Reduce Your Risk for Blood Clots?
Managing your cholesterol is an important part of keeping your heart healthy. The first step is regular cholesterol screening. “All adults should know their cholesterol numbers [and their meaning in relation to their overall cardiovascular risks],” Dr. Shaban says.
If you have high cholesterol, your doctor will often recommend lifestyle changes, such as diet and exercise, to help reduce your cholesterol levels and systemic inflammation. They may also recommend cholesterol-lowering medication, which can also have a protective benefit against developing VTE and thus a heart attack or stroke.
A number of observational studies, including a systematic review, show that people on statins have a lower risk of developing VTE. The mechanism of statin medications, in addition to their lowering of cholesterol numbers, has also been shown to be anti-inflammatory. Statins are prescribed medications, so you should discuss with your provider about the benefits, risks, and potential side effects of long term use.
“If you do have high cholesterol, you should also be very vigilant about other risk factors in your life,” says Shaban, as cholesterol is just one of several major risk factors associated with atherosclerosis. Other manageable risk factors, which are highly linked to community and lifestyle choices and behaviors, include:
When it comes to managing your cholesterol, it is important to be proactive, as the longer you have high levels, the higher the risk of developing atherosclerosis.
“This process starts at a very early age,” says Salim Virani, MD, PhD, a cardiologist at Baylor College of Medicine in Houston. “If we want to maximize the intervention effect, then these [lifestyle changes] should start very early on, because by the time we turn 30 or 40, these plaques have already formed in the vessel wall.”
Work with your healthcare provider to develop a plan that will best manage these risk factors and reduce your risk for atherosclerosis and blood clots. For more information about blood clot prevention, be sure to visit the World Thrombosis Day Campaign.
