Infective endocarditis
Vegetations, destruction and perivalvular extension — TTE first, TOE almost always, and repeat when suspicion persists.
Numbers to remember
- Duke-ISCVID 2023 major imaging criteria: vegetation, perforation, aneurysm, abscess, pseudoaneurysm, fistula, new regurgitation, new prosthetic dehiscence [137]
- TOE if TTE is negative but suspicion remains, with prosthetic valves or devices, and to look for complications [136]
- Repeat TOE within 5–7 days if the first is negative and suspicion stays high [136]
- Vegetation ≥10 mm with embolism despite antibiotics → urgent surgery [136]
Questions echo must answer
Echocardiography is central to the diagnosis of infective endocarditis. It provides major Duke-ISCVID criteria, detects complications and defines surgical indications [136,137].
- Is there a vegetation?Oscillating mass attached to a valve or device, moving independently, on the upstream side of the valve [136].
- Valve destructionRegurgitation, perforation, leaflet aneurysm, chordal rupture [136].
- Perivalvular extensionAbscess, pseudoaneurysm, fistula, prosthetic dehiscence [136,137].
- Embolic riskVegetation size and mobility, mitral location [136].
- Heart failureSeverity of regurgitation, LV function, filling pressure.
Acquisition protocol
- TTE, all standard views, zoomedEvery valve including the tricuspid and pulmonary valves. Look at devices and leads [136].
- VegetationMaximal length and width in the view where it is longest; mobility; attachment [136].
- ColourNew or worse regurgitation; flow through a perforation (outside the coaptation line) [4].
- PerivalvularAortic root thickening or an echolucent space (abscess), pulsatile flow into a cavity (pseudoaneurysm), communication between chambers (fistula) [136].
- ProsthesisRocking motion, paravalvular jets [167].
- TOEIndicated in most patients. More sensitive for small vegetations, prosthetic IE and abscesses [35,136].
- RepeatTOE after 5–7 days when negative with high suspicion, and at any new complication [136].
- Vegetation: location, size, mobility
- Regurgitation and mechanism
- Perforation / aneurysm / chordal rupture
- Abscess / pseudoaneurysm / fistula
- Prosthetic dehiscence
- LV function and filling pressure
- Devices and leads
- TOE performed or planned
Diagnosis & severity
| Finding | Definition [136,137] |
|---|---|
| Vegetation | Oscillating or non-oscillating intracardiac mass on a valve or other endocardial structure, or on implanted material |
| Abscess | Thickened, non-homogeneous perivalvular area with echodense or echolucent appearance |
| Pseudoaneurysm | Pulsatile perivalvular echo-free space with colour flow |
| Perforation | Interruption of endocardial tissue continuity with colour flow through it |
| Fistula | Colour Doppler communication between two neighbouring cavities through a perforation |
| Valve aneurysm | Saccular outpouching of valvular tissue |
| Dehiscence of a prosthesis | Paravalvular regurgitation, with or without rocking motion |
The 2023 ESC guideline adds [¹⁸F]FDG-PET/CT and cardiac CT for prosthetic valve and device endocarditis [136].
Thresholds that change management
- Heart failure from severe regurgitation, obstruction or fistula → emergency or urgent surgery [136].
- Uncontrolled infection (abscess, pseudoaneurysm, fistula, enlarging vegetation, persistent bacteraemia) → urgent surgery [136].
- Embolism prevention: left-sided vegetation ≥10 mm with one or more embolic episodes despite antibiotics → urgent surgery. Vegetation ≥10 mm with severe valve dysfunction → surgery. Isolated large vegetation → case-by-case [136].
- Staphylococcus aureus bacteraemia → echo (and usually TOE) in all patients [136].
- Before discharge and at the end of treatment → echo as a new baseline [136].
Pitfalls & mimics
PitfallA negative TTE does not exclude IE, especially with prosthetic valves, devices, small vegetations and abscesses. TOE is needed [136].
- Mimics: Lambl's excrescences (thin, filamentous, at the closure line), papillary fibroelastoma, myxomatous thickening, ruptured chordae, thrombus, non-bacterial thrombotic (marantic or Libman–Sacks) vegetations, suture material and lead fibrin sheaths [176].
- Early abscess looks like simple root thickening. Repeat imaging, or use PET-CT or CT [136].
- Vegetations shrink or embolise with treatment. Size must be compared on the same modality.
- Right-sided IE (injecting drug use, devices): examine the tricuspid and pulmonary valves and leads carefully.