What are the leaflets on heart valves affected by endocarditis called?

Valve Leaflets Affected by Endocarditis

The leaflets on heart valves affected by endocarditis are called "vegetations." 1 These are pathological structures that form on valve leaflets when microorganisms adhere to damaged endothelial surfaces, creating masses composed of platelets, fibrin, microorganisms, and inflammatory cells.

Characteristics of Vegetations in Endocarditis

Vegetations appear as distinct pathological findings on cardiac imaging with the following features:

• Appearance: Hypoattenuating, often mobile masses of varying size attached to valve leaflets 1
• Composition: Made up of platelets, fibrin, microorganisms, and inflammatory cells 2
• Location: Can form on any heart valve (native or prosthetic) and may extend to perivalvular tissue
• Size: Can range from small to massive (some reported cases have vegetations >4 cm) 3

Imaging Findings of Vegetations

On Echocardiography

• Gold standard for detection of vegetations
• Transthoracic echocardiography (TTE) is the most frequently used imaging study for confirming endocarditis 1
• Transesophageal echocardiography (TEE) has higher sensitivity for detecting vegetations (94%) compared to CT (64%) 1

On CT Imaging

• Vegetations appear as hypoattenuating masses attached to valve leaflets 1
• May be irregularly shaped and mobile 1
• Can be difficult to distinguish from thrombus; clinical context helps with differentiation 1
• Small, erratically moving vegetations may be missed by CT, particularly if only a single-phase scan is available 1

Complications Associated with Valve Leaflet Vegetations

Vegetations on valve leaflets can lead to several serious complications:

• Valvular destruction: Erosion and destruction of valve leaflets leading to regurgitation 1
• Perivalvular involvement: Including abscess formation, mycotic aneurysms, and valve dehiscence 1
• Embolization: Fragments of vegetations can break off and cause embolic events 3
• Heart failure: Due to valvular regurgitation from leaflet destruction 4

Types of Endocarditis Affecting Valve Leaflets

1. Native valve endocarditis: Affects previously normal heart valves
2. Prosthetic valve endocarditis (PVE): Affects mechanical or bioprosthetic valves 1, 5
3. Marantic (non-bacterial thrombotic) endocarditis: Sterile vegetations associated with hypercoagulability states like cancer 6

Clinical Pearls and Pitfalls

• Bioprosthetic valve leaflets affected by endocarditis may be thickened or eroded, suggesting functional insufficiency 1
• The size of vegetations on echocardiography can predict complications such as peripheral embolization 1
• Vegetation growth or failure to decrease in size during antibiotic therapy predicts a complicated course 1
• Early surgical intervention is often necessary for large vegetations (>1 cm) to prevent embolic complications 3
• Don't confuse vegetations with thrombus, which can have a similar appearance on imaging 1

In summary, vegetations are the pathological hallmark of infective endocarditis, representing infected masses attached to valve leaflets that can lead to significant morbidity and mortality if not promptly diagnosed and treated.