Libman-Sacks endocarditis

Libman-Sacks endocarditis (LSE), also known as verrucous endocarditis, is a form of non-bacterial thrombotic endocarditis characterized by large thrombi vegetations over the endocardial surface. It was considered the predominant form of endocarditis in systemic lupus erythematosus (SLE) until treatment with corticosteroids was introduced.

Epidemiology

Data for Libman-Sacks endocarditis comes from several case-controlled studies and cohort studies of patients with SLE. The prevalence of Libman-Sacks endocarditis in one prospective cohort study was estimated by transthoracic echocardiogram at around 11% ¹. However, on post-mortem findings in older studies performed between 1950-1960 identified rates were as high as 35-65% of patients with SLE ².

Clinical presentation

Most patients are asymptomatic as the lesions do not form near the closing line of the valves and hence valvular function is often not affected until later on during the course of the disease. Regurgitant valvular disease is more common than stenotic disease.

Since these patients are at an increased risk of forming thrombi, patients may also present with acute myocardial infarctions or ischemic strokes ³. These patients are also more prone to bacterial endocarditis and several case reports have been documented in literature citing diagnostic dilemmas ⁴.

Pathology

The term describes vegetations on the cardiac valves that are sterile and doesn't show any signs of infection. LSE is characterized by the presence of autoantibodies, such as antiphospholipid antibodies. It has been postulated that there is selective deposition of complement and immune complexes along the endocardial surface leading to aggregation of platelets along the endocardial wall ⁵. The exact mechanism by which antiphospholipid antibodies are involved in the pathogenesis remains unclear. 

Associations

• malignancies 

  • mainly associated with solid tumors such as adenocarcinoma of the pancreas, colon, ovary, lung, biliary, and prostate.

  • increased prevalence rate of around 2.7% with solid tumors versus 0.47% other types of malignancy have been reported.

• systemic lupus erythematosus 

  • may present in 6 to 11% of lupus patients.

• antiphospholipid syndrome 

Radiographic features

Echocardiography

Transthoracic echocardiography (TTE) had been considered the best initial test for the evaluation of LSE. However, recent studies have identified that transesophageal echocardiogram (TOE) may have a higher sensitivity, specificity, positive, and negative predictive value compared to TTE ⁶.

Further studies have demonstrated that three-dimensional echocardiography (3D-TEE) is better at characterizing valvular lesions (aortic and mitral valve lesions) ⁷. In these studies, 3D-TEE also detected more lesions in patients with cerebrovascular disease ⁷.

MRI

Currently, the role of 4D-flow MRI imaging as a useful non-invasive tool for evaluating abnormal flow patterns, ventricular dimensions, stroke volume, and regional myocardial function, is being investigated. Some early studies have shown promising results as they have been able to more accurately demonstrate the above parameters compared to traditional TOE ⁸.

Treatment and prognosis

The management of Libman-Sacks endocarditis consists of managing the underlying disease process with appropriate immunosuppressant therapy. Patients may benefit from anticoagulation. Surgery or additional pharmacotherapy may be indicated in acute valvular rupture or heart failure.

History and etymology

It was first described by Emanuel Libman (1872-1946) and Benjamin Sacks (1896-1971) ^ref, American pathologists, in their 1924 paper ^9,10.