Libman-Sacks Endocarditis

Libman-Sacks endocarditis is a sterile form of nonbacterial thrombotic endocarditis. Fibrin and platelets accumulate on injured valve endothelium, creating verrucous vegetations that contain no microorganisms. The mitral and aortic valves are affected most often. The usual clinical setting is systemic lupus erythematosus (SLE), antiphospholipid syndrome (APS), or both. Immune-complex deposition and inflammation injure the valve surface; antiphospholipid antibodies add a prothrombotic influence by disrupting normal antithrombotic mechanisms. The result is a valve lesion produced by autoimmunity and thrombosis rather than bacterial invasion. Repeated cycles of injury, thrombosis, healing, and fibrosis can thicken the valve and impair leaflet coaptation. Regurgitation is the usual haemodynamic consequence; stenosis is uncommon. The vegetations can also embolize. This explains why a patient may present with a transient ischaemic attack, stroke, or peripheral arterial occlusion even when the valve lesion has caused no previous murmur or heart-failure symptoms. Many lesions are clinically silent and found during echocardiography. Valve vegetations occur in roughly one in ten patients with SLE and are associated with longer disease duration, greater lupus activity, anticardiolipin antibodies, and APS. A damaged valve surface...