Libman-Sacks endocarditis

Libman-Sacks endocarditis
ICD-10	I39, M32.1
ICD-9	710.0
DiseasesDB	29254
eMedicine	med/1295
MeSH	D008180

Template:Search infobox Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Sara Mohsin, M.D.[2]

Synonyms and keywords: Nonbacterial thrombotic endocarditis (NBTE), Marantic endocarditis, Verrucous endocarditis

Overview

Libman-Sacks endocarditis is a form of nonbacterial endocarditis that is seen in systemic lupus erythematosus. It is the most common cardiac manifestation of lupus. It can be associated with the development of aortic insufficiency. LSE is a sterile and verrucous vegetation around the heart valves. LSE is usually associated with autoimmune diseases especially SLE and APS. LSE mostly affects mitral and aortic heart valves, which may cause thromboembolic cerebrovascular events, valvular regurgitation, and increased risk of infective endocarditis. Although APS and valvular involvements are not rare, and have mostly low clinical significance, they could cause severe complications. Secondary APS compared to primary APS also have higher rate of cardiac involvement, mostly due to the autoimmune causes related to the SLE. Here, we report three cases of LSE in patients with SLE and secondary APS diagnosed after presenting with neurological manifestations.

Historical Perspective

• In 1924, the two American physicians Emanuel Libman, and Benjamin Sacks, working at Mount Sinai Hospital, New York, described the Libman-Sacks endocarditis for the first time, hence, it's named after them. They first presented the complete clinical picture of it with or without skin lesions and described it as unusual non-bacterial endocarditis with verrucous vegetations adherent to the endocardium.
• In 1983, Graham Hughes described the anti-phospholipid antibody syndrome for the first time while working as a rheumatologist at St Thomas Hospital. He named it anticardiolipin syndrome (also known as Hughes' syndrome named after him) and described it has the following three characteristics:
  • Venous and/or arterial thrombosis
  • Recurrent pregnancy loss
  • Presence of antiphospholipid antibodies
• In 1985, the association between Libman-Sacks endocarditis and antiphospholipid antibody syndrome was noted for the first time.

Pathophysiology

• The vegetations are formed from strands of fibrin, neutrophils, lymphocytes, and histiocytes.
• The mitral valve is typically affected, and the vegetations occur on the ventricular and atrial surface of the valve.
• Libman-Sacks lesions rarely produce significant valve dysfunction and the lesions only rarely embolize.

Pathology

• The pathology is the same as nonbacterial thrombotic endocarditis except focal necrosis (hematoxylin bodies) can be found only in Libman-Sacks endocarditis.

Epidemiology and Demographics

• Libman-Sacks' vegetations can be found in approximately 1 of 10 patients with SLE.
• They are associated with lupus duration, disease activity, anticardiolipin antibodies, and APS manifestations.
• The incidence of positive findings on echocardiography is variable but detection is higher with transoesophageal ultrasound and the frequency is higher in those with positive antiphospholipid antibodies.
• Thickening of the leaflets is more common than finding vegetations.
• Abnormalities on ultrasound may be found in around a third with APS.
• The presence of these findings, as with the disease, is 5 to 9 times more frequent in women than in men.
• The typical patient is a young woman, although it can rarely occur in children.
• Nonbacterial thrombotic endocarditis (NBTE) is a rare condition most often found postmortem with rates in autopsy series ranging from 0.9 to 1.6 percent.

• It has been reported in every age group, most commonly affecting patients between the fourth and eighth decades of life with no sex predilection.
• Patients with advanced malignancy and those with systemic lupus erythematosus are the most common populations affected by NBTE.
• One autopsy series reported that, compared to the general population, patients with underlying malignancy have a higher rate of NBTE (1.25 versus 0.2 percent).
• When compared to other malignancies, higher rates were reported in those with adenocarcinoma (eg, lung, colon, ovary, biliary and prostate) (2.7 versus 0.47 percent) with the highest rates observed in patients with mucin-secreting and pancreatic adenocarcinoma (10 percent).
• In patients with systemic lupus erythematosus, observational studies using transthoracic echocardiography have reported prevalence rates of 6 to 11 percent, with higher rates (43 percent) observed when the more sensitive transesophageal echocardiography was performed.

Natural History, Complications and Prognosis

Complications

• Systemic emboli may occur but they are probably not very common.
• The risk is much higher with mitral stenosis and subsequent atrial fibrillation.
• When strokes occur it is difficult to know if they were due to systemic emboli or the underlying pathology of SLE or APS.
• Valvular disease can lead to heart failure.
• Maternal SLE with anti-Ro/SS-A (Sjögren's syndrome antigen A) autoantibodies is associated with congenital heart block in the baby in about 1 or 2%. It is usually complete but can be 1st or 2nd degree.
• The rate of recurrence is around 16%.
• Fluorinated steroids that do not cross the placenta may be beneficial.

Prognosis

• All the SLE patients have a shorter life span.
• The major cause of mortality in SLE patients is occurrence of cardiovascular events as SLE is a risk factor for premature & accelerated coronary atherosclerosis and CAD (coronary artery disease) due to the following associated factors:
  • Hypertension
  • Hyperlipidemia
  • Chronic inflammation
  • Chronic glucocorticoids use

History and symptoms

• Most patients with Libman-Sacks endocarditis are asymptomatic.
• If valves are severely affected there may be features of the valve disease.
• Mitral valve disease is more common than aortic valve disease.
• Regurgitation is more frequent than stenosis and involvement of the tricuspid or pulmonary valves is unusual.
• Systemic embolism may occur with effects depending upon the destination of the emboli but brain and kidney are likely victims.
• Emboli can cause blockage of the peripheral circulation.
• The vegetations of Libman-Sacks endocarditis are sterile but secondary infective endocarditis can occur.
• There may or may not be typical features of SLE with the characteristic butterfly rash, fever and arthritis or features of APS, including recurrent miscarriage.

Physical Examination

• left ventricular hypertrophy, causing displacement of the apex beat.
• congestive heart failure physical exam findings.
• IE findings
• Mitral valve disease findings
• Aortic valve disease findings

Laboratory findings

• Blood culture is important to exclude infective endocarditis (IE), which may coexist.
• Investigations for SLE, including antiphospholipid antibodies and other autoantibodies. False-positive serology in the form of VDRL is common in SLE and anticardiolipin antibodies increase the risk of cardiac abnormalities.
• FBC may show raised neutrophils and some anaemia.

Imaging findings

Echocardiography

• Echocardiography should be employed, although not all lesions will be detected.
• Results with transoesophageal echo are superior but it is an invasive procedure.

Chest X-Ray

• CXR may show cardiomegaly and pulmonary congestion if the disease is severe.
• Calcification of lesions is uncommon.

Other Diagnostic studies

Cardiac Catheterization

• If valvular disease seems severe then cardiac catheterization may be required with a view to valve replacement.

Treatment

• There is no specific treatment for Libman-Sacks endocarditis.
• Steroids and immunosuppressive agents are useful in the treatment of the underlying disease but there is some controversy about their role in the pathogenesis of vegetations:
  • Compared with reports of postmortems on patients before the advent of steroids, those that have been treated have smaller and fewer lesions, mostly on one valve and usually confined to the left side.
  • Hypertension was 5 times as common and congestive heart failure was 8 times as common as in the days before corticosteroids. The steroids may be directly responsible for hypertension and heart failure. This paper was from 1975 and it is possible that better control of hypertension and heart failure may offset these problems today.
  • Expert opinion seems to conclude that steroids are detrimental to Libman-Sacks endocarditis although some praise them. The situation is far from certain.
• Advice for procedures creating a risk of infective endocarditis can be found in the separate record Prevention of Endocarditis.
• If there are systemic emboli then anticoagulation with warfarin is beneficial but the possible role of aspirin has not been adequately investigated. If there is evidence of 1 cerebrovascular event, anticoagulation is advised.
• In serious valve disease it may be necessary to replace valves. Mechanical valves may be more susceptible to thromboemboli but it is uncertain if bioprosthetic valves are at risk of the disease. The operative mortality of mitral valve replacement in this condition may be as high as 25%.

References

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