Active Infective Endocarditis Pathology Table

On gross examination, infected thrombi of variable size, commonly known as "vegetations," are detected along the lines of valve closure or at the low pressure end of jet lesions [2,9]. They are usually gray, pink, or brown and are often friable (Figures 2.1, 2.5). They may be single or multiple and may affect more than one valve. Common sites are usually on the downstream side of the intracardiac high-velocity flow jets, such as the atrial side of the mitral valve or the left atrial endocardium in cases of mitral insufficiency, the ventricular side of the aortic valve, the ventricular septum or the anterior mitral leaflet in cases of aortic insufficiency, or on the right ventricular endocardium in ventricular septal defects. Infection may also involve the intima of a blood vessel distal to a coarctation or involve the pulmonary artery side of an infected patent ductus arteriosus (Figure 2.6). Left-sided valve lesions are more common than right-sided lesions except for cases related to interventional devices, catheters, or IVDU [9].

Vegetations may be located anywhere on the valve cusp or leaflet or endocardial surface. In fact this is an important distinguishing feature to note, as valve thrombi associated with non-bacterial thrombotic endocarditis (NBTE) and those related to rheumatic fever do not have this variability in location, and are usually along the

Table 2.1. Pathology of Valvular Sequelae of Infective Endocarditis Acute

Vegetations—infected thrombi Valve ulcers or erosions Aneurysms Chord rupture Annular and ring abscess Endocardial jet lesions Flail leaflet or cusp Chronic Perforations Calcified nodules Valve tissue defects Valve fibrosis lines of valve closure. Libman Sacks lesions in lupus patients may be on both sides of the valve. Thrombi from NBTE, rheumatic fever, Libman Sacks, are not associated with valve destruction.

The valve structures may also manifest destructive lesions leading to perforations, defects, aneurysms, erosions, and chordal ruptures (Figures 2.7, 2.8). The amount of thrombus and destruction may completely mask the underlying predisposing valve disease. Thrombi may obstruct the valvular orifice, creating stenosis, but valvular insufficiency is a much more common complication. Chordae may rupture resulting in flail leaflets [25]. Leaflet or cusp aneurysms bulge toward the flow surface and may resemble "windsocks," and IE is the most common cause for leaflet aneurysm or divertic-ulum (Figure 2.9). If the aneurysm tip ruptures,

Figure 2.5. Gross photograph of excised tricuspid valve from a patient with intravenous drug use related bacterial infective endocarditis.Numerous large, infected vegetations are present. Ruler = 1 cm.

Figure 2.5. Gross photograph of excised tricuspid valve from a patient with intravenous drug use related bacterial infective endocarditis.Numerous large, infected vegetations are present. Ruler = 1 cm.

Infective Endocarditis LeafletsWindsock Ductus Arteriosus
Figure 2.6. Gross photograph of an opened pulmonary trunk artery with the opening of a patent ductus arteriosus that had become infected.There is ragged material surrounding the ductus opening (D), and the pulmonary valve (PV) is also destroyed by the infection.

the valve may become severely regurgitant due to cusp or leaflet defects.

On microscopic examination, the appearance of the vegetation depends upon both the virulence and destructiveness of the organism and the duration of the infection. Early in the disease course there are fibrin, neutrophils, and clumps of organisms (Figure 2.2). With therapy the organisms may calcify, and the thrombi organize from the base. Organizing thrombus may show no easily recognizable organisms and only show acute and chronic inflammation with neovascularization and fibroblastic proliferation. With thrombus organization giant cells may be seen. If giant cells are prominent one should consider serology for Coxiella or fungi. Pathological changes in the infected valve tissue depend on the chronicity or duration of the infection, the virulence of the organism and the status of the original valve itself. Electron microscopy, immunofluorescence, polymerase chain reaction or molecular techniques are contributory in the search for organisms [18,21-23].

Figure 2.7. Gross photograph of excised aortic valve with infective endocarditis. There are diffuse ragged cusp defects and the right cusp has a ruptured cusp aneurysm.Ruler = 1 cm.

Figure 2.8. Gross photograph of an excised mitral valve leaflet with infective endocarditis. There is chordal vegetation with chord destruction. Most of the leaflet has no remaining intact chords. Ruler = 1 cm.

Figure 2.8. Gross photograph of an excised mitral valve leaflet with infective endocarditis. There is chordal vegetation with chord destruction. Most of the leaflet has no remaining intact chords. Ruler = 1 cm.

Chordal Endocarditis
Figure 2.9. Gross photograph of excised anterior mitral leaflet with infective endocarditis related aneurysm (windsock lesion) formation.These infected aneurysms eventually erode through and form valve perfo-rations.Ruler = 1 cm.
Infective Endocarditis Vegetation
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Responses

  • keke
    What is active infective pathology?
    1 year ago

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