Endocarditis is a type of heart disease that involves inflammation of the inner lining of the heart and its valves. Most cases of endocarditis are caused by bacterial infections. However, a type of endocarditis known as Libman-Sacks endocarditis (LSE) isn’t caused by bacterial infection. Instead, it’s associated with other health conditions, including autoimmune conditions and various types of cancer, causing abnormal growths in the heart. The condition is named after Dr. Emanuel Libman and Dr. Benjamin Sacks, who first described it in 1924. It is also known as nonbacterial thrombotic endocarditis (NBTE).

LSE interferes with the function of your heart valves, which open and close to keep blood flowing in the right direction through your heart. In this article, we’ll discuss what LSE is, how it’s caused, and what treatments are available.

What Is Libman-Sacks Endocarditis?

To understand what LSE is, it’s important to first learn how your heart works. When blood flows through your heart, it’s directed by cardiac valves — or strong flaps of tissue (known as cusps or leaflets) that open and close, helping blood flow from one chamber of your heart to another. This opening and closing motion produces the sound of your heartbeat.

LSE, also known as verrucous endocarditis or NTBE, is an inflammatory heart condition that damages your heart valves. Specifically, LSE causes what’s called vegetations (abnormal growths) to form on the valves that interfere with their function. These vegetations are masses made from deteriorating platelets (small blood cells) and strands of fibrin (a protein that helps with clotting).

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Your heart has four valves: mitral, aortic, tricuspid, and pulmonary. LSE typically affects the mitral and aortic valves. When they become damaged, blood may begin flowing backward in your heart. This is known as regurgitation, and it can interfere with your heart’s ability to carry blood to other parts of your body.

What Causes Libman-Sacks Endocarditis?

LSE is a type of nonbacterial thrombotic endocarditis. This means it’s not caused by a bacterial infection. Rather, it’s caused by inflammation seen in people with certain autoimmune diseases — such as lupus and antiphospholipid syndrome (APS) — or in people with certain types of cancer.

If you have an autoimmune disease, your body’s immune system recognizes your own tissues as foreign. Autoantibodies tell your immune cells to attack your tissues, creating inflammation and causing damage. In lupus, autoantibodies recognize certain antigens (types of protein) on your joints, kidneys, and skin and tell your immune system to attack.

APS is caused by autoantibodies that make your blood clot more easily than normal. Certain types of cancer can also activate the body’s blood-clotting process, particularly solid tumors found in the lung, colon, or pancreas.

Altogether, these three types of conditions can increase inflammation and the risk of thrombi (blood clots). Doctors and researchers believe that inflammation first damages the valve lining, making it easier for vegetations to form in LSE. These valvular lesions typically contain immune complexes (autoantibodies stuck to multiple antigens), along with platelets and fibrin (cells and proteins used to make blood clots).

As a result, your valves become thickened, and they may not open and close properly. This condition can lead to regurgitation. In some cases, the opening near the valve may become narrowed (known as stenosis).

Who Develops Libman-Sacks Endocarditis?

LSE is a rare condition, affecting 0.9 percent to 1.6 percent of the general population, according to a 2022 book from StatPearls. It’s more common in adults between the ages of 40 and 80, although it can develop in people of any age. There doesn’t appear to be a sex difference. However, women account for 90 percent of lupus cases, according to the Lupus Foundation of America — and the condition is 2 to 3 times more prevalent in women of color than white women. APS is 3.5 times more common in women than in men, according to the journal Frontiers in Immunology.

According to the StatPearls book, LSE is present in 6 percent to 11 percent of people with lupus, 33 percent of people with APS, and 1.25 percent of people with solid tumors. There’s also a correlation between activity and length of time living with lupus and with LSE. This means that the longer a person has had lupus or the more severe it is, the more likely they are to develop new vegetations or have their heart valve function become worse.

Doctors and researchers have found that people with both lupus and antiphospholipid antibodies are more likely to have LSE compared to those having only one of the conditions.

Symptoms of Libman-Sacks Endocarditis

Most people with LSE don’t experience any symptoms. Oftentimes, LSE is diagnosed after death when the medical examiner is performing an evaluation for heart disease or other complications.

However, in more severe cases, people may develop complications that cause recognizable symptoms such as:

• Heart failure — A serious condition caused by valve damage and dysfunction (typically seen with mitral regurgitation) that can lead to shortness of breath, fatigue, and swelling in the feet and legs
• Secondary infective endocarditis — A bacterial infection that affects the inner lining of the heart and valves, which may cause chest pain, weight loss, fever, and fatigue
• Systemic thromboembolism — Blood clots throughout the body that block blood flow to the extremities that may cause numbness and coldness in the arms and legs, pain, or vomiting
• Cerebrovascular embolism — A blood clot that blocks blood flow to the brain, which may cause stroke symptoms, such as trouble speaking, vision loss, numbness or weakness in the arms or legs, or memory loss

People with lupus and APS may also experience underlying symptoms of their diseases. In some cases, it can be difficult to tell the difference between lupus and APS symptoms and those of LSE.

How Is Libman-Sacks Endocarditis Diagnosed?

Unfortunately, there’s no one test to diagnose LSE. Instead, doctors will perform a physical exam, blood work, and imaging tests to rule out other conditions and make a final diagnosis.

Physical Exam

During your physical exam, your doctor will listen to your heart to check for any murmurs or abnormal whooshing sounds when your heart beats. Murmurs tell them that blood may not be flowing through your heart valves properly. If your doctor hears a murmur or finds other signs of heart problems, they may refer you to a cardiologist who specializes in heart diseases for more testing.

Blood Work

If your doctor suspects you have lupus or APS causing your LSE, they may order additional blood work to confirm a diagnosis. Identifying the underlying cause of LSE can help you get the treatment you need to control your conditions. Blood tests that may be ordered include:

• Antiphospholipid antibody (anticardiolipin antibody) test — Used to diagnose APS
• Antinuclear antibody and anti-DNA antibody tests — Used to diagnose lupus
• Blood cultures — Used to check for bacterial infections
• Coagulation profile — Measures your blood’s clotting ability
• Complete blood count (CBC) — Measures your red blood cells, white blood cells, and platelet counts

Imaging Tests

Imaging tests help your doctor check for LSE vegetations, thickening, and any other valve abnormalities. Echocardiograms (or echos) are the most common, which use sound waves to create images of your heart. Your cardiologist may order one of two types of Libman-Sacks endocarditis echo scans:

• Transthoracic echocardiography (TTE) — A noninvasive imaging test that uses a transducer (wand) placed on your chest to take images of your heart and valves
• Transesophageal echocardiography (TEE) — An invasive imaging test during which a transducer is inserted down the esophagus closer to the heart to get more detailed images

Your cardiologist may also use Doppler echocardiography, which measures how blood cells move through your heart and valves. This method can help identify if you have LSE and which valves are involved.

How Is Libman-Sacks Endocarditis Treated?

Currently, there aren’t any specific treatments recommended for LSE. Your doctor will treat symptoms or complications you have from LSE, lupus, or APS. Depending on your specific case and its severity, your doctor will go over which therapies are best for you.

Corticosteroids are immunosuppressive drugs commonly used to treat inflammation in lupus. They’ve also been found to help heal valve lesions. However, some studies show that they can cause scarring, making LSE worse. For people with APS, anticoagulation therapy with blood thinners can help prevent blood clots. One commonly prescribed blood thinner is warfarin (Coumadin).

In LSE cases with severe valvular dysfunction, a surgical procedure such as a valve replacement or repair may be necessary. For example, mitral valve surgery may be done to fix the existing mitral valve or replace it with a prosthetic (artificial valve). Blood thinners such as heparin or even warfarin may be used for a short period of time or long term to prevent further embolism.

The Bottom Line

Libman-Sacks endocarditis is a rare but serious condition that can damage the heart valves and lead to complications like heart failure or stroke. It is often linked to autoimmune diseases like lupus and can be diagnosed through imaging tests and blood work. Treatment may include medication to manage symptoms and prevent blood clots, as well as surgery to repair or replace damaged heart valves. With prompt diagnosis and proper care, people with LSE can manage their symptoms and reduce complications.

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