Libman-Sacks Endocarditis Workup

Updated: Dec 23, 2014
  • Author: Xiushui (Mike) Ren, MD; Chief Editor: Richard A Lange, MD, MBA  more...
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Workup

Approach Considerations

Lab tests

Lab studies to test for Libman-Sacks endocarditis should include the following:

  • Blood cultures - Infective endocarditis should be excluded
  • Complete blood count (CBC) - Neutrophilia may indicate infection; coexistent anemia may be present
  • Antiphospholipid antibody - Including anticardiolipin antibody, lupus anticoagulant, Venereal Disease Research Laboratory (VDRL), and Russell viper venom test
  • Coagulation profile - With prothrombin time and activated partial thromboplastin time
  • Antinuclear antibody - With or without antiextractable nuclear antigens or anti–beta2 glycoprotein
  • Anti-deoxyribonucleic acid (DNA) antibody assay (double stranded) - A workup for systemic lupus erythematosus may be indicated

Chest radiography

Cardiomegaly and pulmonary congestion may be noted on chest radiography; calcified masses and valvular tissue are possible but rare.

Echocardiography

Transthoracic echocardiography (TTE) is valuable for the initial evaluation of cardiac murmurs and for quantification of left atrial volume and left ventricular volume, mass, and contractile function. Transesophageal echocardiography (TEE) is useful in the detection of valvular lesions (especially in the left-sided valves), with greater sensitivity and specificity for this than TTE can achieve.

Angiography

Coronary angiography can be performed if cardiac ischemia is suggested and if valve replacement surgery is indicated, because systemic lupus erythematosus is associated with premature atherosclerotic coronary artery disease and coronary vasculitis.

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Echocardiographic Studies

Whether transthoracic echocardiography (TTE) or transesophageal echocardiography (TEE) should be used depends on the clinical scenario.

TTE is most appropriate for the initial evaluation of cardiac murmurs and quantification of left atrial volume and left ventricular volume, mass, and contractile function.

One study compared TTE with TEE for the diagnosis of Libman-Sacks endocarditis. [6] Using TEE as the standard, TTE demonstrated low sensitivity (63% overall, 11% for valve vegetations), low specificity (58%), low negative predictive value (40%), and moderate positive predictive value (78%) for detection of Libman-Sacks endocarditis. Thus, TEE should be performed when the TTE is nondiagnostic or when the pretest probability is high.

The use of 3-dimensional (3D) echocardiography in Libman-Sacks endocarditis has been described. [7]

Results of echocardiography

Irregular borders, heterogeneous echodensity, and an absence of independent motion characterize the masses (ie, verrucous vegetations) on the cardiac valves and endocardium. The masses are usually small and sessile, but they can be as large as 10mm. The basal portion and midportion of the mitral and aortic valves are involved most commonly.

Diffuse leaflet thickening of the mitral and aortic valves or focal leaflet thickening of the midbasal leaflet can be observed.

Acoustic shadowing suggesting calcification is possible but uncommon. Valvular regurgitation can be seen. Valvular stenosis may be present but is rare. Left ventricular enlargement and/or dysfunction can be observed.

Coexistent cardiac complications of systemic lupus erythematosus may include pericardial effusion or thickening, left ventricular hypertrophy (due to hypertension), left ventricular dilatation, left ventricular segmental dysfunction, left ventricular global dysfunction, or elevated pulmonary artery pressure.

TEE offers superior resolution of cardiac valves and helps to detect valvular lesions (especially in left-sided valves) with greater sensitivity and specificity than TTE.

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Cardiac Catheterization

Perform coronary angiography if cardiac ischemia is suggested and if valve replacement surgery is indicated, because systemic lupus erythematosus is associated with premature atherosclerotic coronary artery disease and coronary vasculitis. However, if large aortic lesions are present, noninvasive coronary artery evaluation (such as computed tomography [CT] angiography) may be indicated because catheterization may cause embolization.

Left-sided pressure tracings, ventriculography, and aortography might yield additional information regarding valvular dysfunction and left ventricular function.

Right-sided heart catheterization is useful for determining pulmonary artery pressure and pulmonary vascular resistance because cardiac and pulmonary pathology can occur with lupus. Use caution because the severity of valvular dysfunction in the presence of pulmonary disease may be overestimated.

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Histologic Findings

The different stages of Libman-Sacks endocarditis have been described as active, active and healed, and healed lesions. These can be characterized as follows:

  • Active verrucae - Consist of clumps of fibrin on and within the valvular leaflet tissue, which is focally necrotic, with plasma cells and lymphocytes
  • Combined active and healed lesions - Contain vascularized, fibrous tissue adjacent to fibrinous and necrotic areas
  • Healed lesions - Consist of dense, vascularized, fibrous tissue

Histologic examinations of patients with lupus who undergo valve replacement often show the latter 2 stages, with the excised, dysfunctional leaflet tissue being fibrotic, retracted, and partially calcified with fibrinous deposits. Overlying thrombi have also been reported on valves examined at operation. Hematoxylin bodies can also be present.

Immunoglobulin and complement deposits have been identified subendothelially and in the core of vegetations.

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