Clinical meaning
Libman-Sacks endocarditis (LSE) is a form of non-bacterial thrombotic endocarditis (NBTE) characterized by sterile verrucous vegetations composed of fibrin, immune complexes, platelet-fibrin thrombi, and inflammatory debris deposited on heart valve leaflets. It is most commonly associated with systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS), occurring in approximately 10-15% of SLE patients. The pathogenesis involves autoimmune-mediated endothelial damage on the valve surface. In SLE, circulating immune complexes (anti-DNA antibodies complexed with nucleosomal antigens), complement activation, and antiphospholipid antibodies cause endothelial injury on the valve leaflets. The damaged endothelium triggers platelet adhesion and fibrin deposition, forming the characteristic vegetations. Unlike infective endocarditis (IE), LSE vegetations are sterile (no organisms), smaller (usually 1-4 mm), and tend to occur on both surfaces of the valve leaflet (both atrial and ventricular sides of mitral valve), whereas IE vegetations are typically on the atrial side of AV valves. The mitral valve is most commonly affected (>50%), followed by the aortic valve (approximately 30%). Vegetations can be found on the ventricular surface, atrial surface, or both surfaces of the valve, and may extend onto the chordae...