Question
Vegetation’s of the heart
Answer
Vegetations are friable, thrombotic masses composed of fibrin, platelets, and organisms/inflammatory cells attached to heart valves. Types:
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Infective endocarditis vegetations: Large, bulky, friable, irregular masses on valve leaflets that may extend onto the chordae; may erode/destroy the underlying valve leaflet; composed of fibrin, platelets, and abundant colonies of organisms (bacteria/fungi) with associated inflammatory cells. Prone to embolization (septic emboli).
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Non-bacterial thrombotic endocarditis (NBTE) vegetations: Small, sterile, bland thrombi (fibrin and platelets only, no organisms/inflammation) attached to the line of closure of valve leaflets, seen in hypercoagulable states (e.g., malignancy) and debilitated patients; do not destroy the valve.
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Libman-Sacks endocarditis (associated with SLE): Small, sterile vegetations attached to either surface of the valve leaflets (unlike NBTE, may be on the undersurface too), composed of fibrin, immune complexes, and inflammatory cells.
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Rheumatic heart disease vegetations: Small, warty, granular vegetations arranged in a row along the line of closure of the valve (especially mitral valve), composed of fibrin and platelets deposited over sites of endothelial damage caused by Aschoff body-related inflammation; do not embolize significantly but leave fibrous thickening and scarring (chronic RHD) upon healing.
Vegetations are clinically significant as sources of systemic embolization, valve destruction leading to regurgitation/stenosis, and — in infective endocarditis — as a nidus for ongoing sepsis.