Cardiology > Non-infectious Endocarditis (Libman-Sacks Endocarditis)  

Background 

Libman-Sacks endocarditis (LSE) is a form of nonbacterial thrombotic endocarditis (NBTE) characterized by sterile vegetations on cardiac valves. It is most commonly associated with systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS). Unlike infective endocarditis, LSE vegetations do not contain microorganisms and are the result of immune complex deposition, endothelial injury, and hypercoagulability. These vegetations are typically located on both sides of the valve leaflets and may lead to valvular dysfunction and thromboembolic complications. 

II) Classification/Types 

By Associated Condition: 

• • • SLE-associated Libman-Sacks endocarditis 

• • • Antiphospholipid syndrome-associated LSE 

• • • NBTE associated with malignancy (marantic endocarditis) 

• • • Non-autoimmune NBTE (trauma, cachexia, sepsis) 

By Valve Involvement: 

• • • Mitral valve (most common) 

• • • Aortic valve 

• • • Tricuspid and pulmonary valves (rare) 

Pathophysiology 

Endothelial injury from circulating immune complexes in autoimmune conditions or from procoagulant factors in malignancy promotes thrombus formation. Platelets and fibrin deposit on the valve leaflets, forming sterile vegetations. In SLE, immune complex-mediated inflammation contributes to valve thickening, fibrosis, and dysfunction. These vegetations are friable and may embolize, particularly in patients with APS. Unlike IE, there is no microbial invasion, but the valve damage and systemic sequelae can be severe. 

Epidemiology 

• • Seen in up to 10% of patients with SLE (higher in active disease) 

• • Found in 30–50% of patients with antiphospholipid syndrome on autopsy 

• • More common in females due to SLE predominance 

• • Often subclinical and detected incidentally or at autopsy 

• • Risk of embolic events (e.g., stroke) is elevated 

Etiology 

I) Causes 

• • Systemic lupus erythematosus (SLE) 

• • Antiphospholipid syndrome (primary or secondary) 

• • Advanced malignancy (especially mucin-producing adenocarcinomas) 

• • Wasting syndromes, sepsis, or hypercoagulable states 

II) Risk Factors 

• • Active SLE or high SLE disease activity index 

• • Positive antiphospholipid antibodies (aPL) 

• • History of thromboembolism 

• • Underlying malignancy or chronic debilitating illness 

• • Prolonged catabolic states or immunosuppressive therapy 

Clinical Presentation 

I) History (Symptoms) 

• • Often asymptomatic and discovered incidentally 

• • Symptoms may be due to: 

• • Valvular dysfunction: dyspnea, fatigue 

• • Embolic phenomena: stroke, TIA, limb ischemia 

• • Systemic lupus activity: arthralgias, rash, fever 

II) Physical Exam (Signs) 

• • Heart murmur (often new or changing) 

• • Signs of embolism (e.g., stroke, splenic infarcts) 

• • Features of active lupus: malar rash, arthritis, oral ulcers 

• • No signs of infection (e.g., no fever, chills) 

Differential Diagnosis (DDx) 

• • Infective endocarditis 

• • Rheumatic heart disease 

• • Antiphospholipid syndrome with arterial thrombosis 

• • Degenerative valvular disease 

• • Cardiac myxoma or other masses 

Diagnostic Tests 

Initial Work-Up 

• • Transthoracic echocardiography (TTE): Initial imaging; may miss small vegetations 

• • Transesophageal echocardiography (TEE): Higher sensitivity; reveals small, sessile, broad-based vegetations on atrial surface of mitral valve or ventricular surface of aortic valve 

• • Blood cultures: Negative (to rule out IE) 

• • ANA, anti-dsDNA, complement levels: Assess lupus activity 

• • Antiphospholipid antibodies (aPL): Anticardiolipin, β2-glycoprotein I, lupus anticoagulant 

• • MRI/CT brain: If neurologic symptoms are present (for embolic stroke) 

• • CBC, ESR/CRP: May show anemia, leukopenia, elevated inflammatory markers in active lupus 

Treatment 

I) Initial Approach 

• • Treat underlying autoimmune disease (e.g., lupus or APS) 

• • Prevent systemic embolization with anticoagulation in selected patients 

• • Monitor for progression of valvular disease 

II) Medications 

Patient Education, Screening, Vaccines 

Education 

• • Importance of lupus and APS disease control 

• • Report symptoms suggestive of embolism or heart failure 

• • Need for routine echocardiographic surveillance 

Screening 

• • Baseline and periodic echocardiography in patients with SLE/APS 

• • Regular aPL antibody monitoring 

• • Screening for thromboembolic complications 

Vaccinations 

• • Influenza and pneumococcal vaccines in all SLE patients 

• • HPV and COVID-19 vaccines as per guidelines 

Consults/Referrals 

• • Cardiology: For evaluation of valve disease and follow-up imaging 

• • Rheumatology: For management of SLE or APS 

• • Neurology: If embolic stroke or TIA occurs 

• • Hematology: For anticoagulation decisions in APS 

Follow-Up 

Short-Term 

• • Monitor disease activity and valve function 

• • Adjust immunosuppressive and anticoagulation therapy as needed 

Long-Term 

• • Regular echocardiography to assess vegetations or progression to regurgitation/stenosis 

• • Assess for thromboembolic risk and recurrence 

• • Monitor renal function and inflammatory markers 

• • Continue long-term rheumatology and cardiology follow-up 

Prognosis 

• • Generally favorable with good control of SLE or APS 

• • Risk of embolism is significant, especially in APS 

• • Valvular dysfunction may necessitate surgical repair or replacement 

• • Early detection and treatment improve outcomes 

• • Poor prognosis if unrecognized or associated with malignancy or severe lupus flare