What are the typical echocardiography (echo) findings in a patient with infective endocarditis?

Echocardiographic Findings in Infective Endocarditis

Echocardiography is the gold standard imaging modality for diagnosing infective endocarditis, with transesophageal echocardiography (TEE) demonstrating superior sensitivity (>90%) compared to transthoracic echocardiography (TTE) for detecting characteristic findings.

Primary Echocardiographic Findings

Vegetations

• Vegetations are the hallmark finding in infective endocarditis and appear as mobile, echogenic masses attached to valvular structures 1
• Vegetation size, mobility, and location are critical characteristics that help predict complications and guide management 1
• Large vegetations (>10 mm) on the anterior mitral leaflet carry the highest risk for peripheral embolization 1

Valvular Damage

• Valvular destruction with resultant regurgitation is a common finding 1
• Valve perforation appears as interruptions in valve tissue continuity with abnormal flow on color Doppler 1, 2
• Valve dehiscence, particularly in prosthetic valves, manifests as excessive mobility of the valve during the cardiac cycle 1, 3

Perivalvular Complications

• Paravalvular abscesses appear as thickened, non-homogeneous perivalvular areas with echodense or echolucent appearance 1
• Pseudoaneurysms present as pulsatile perivalvular echo-free spaces with flow detected on color Doppler 1
• Fistulous tracts may develop between cardiac chambers or vascular structures 1

Comparative Diagnostic Accuracy

TTE vs. TEE

• TTE has approximately 75% sensitivity for detecting vegetations, which increases to 85-90% with TEE 1, 3
• TEE demonstrates approximately 99% sensitivity for native valve endocarditis, significantly outperforming TTE 3, 1
• For prosthetic valve endocarditis, TEE has approximately 90% sensitivity compared to only 50% for TTE 3, 4
• In right-sided endocarditis, TTE and TEE perform comparably in detecting tricuspid vegetations and regurgitation 1, 3

Prognostic Indicators on Echocardiography

• Intracardiac abscess and left ventricular ejection fraction <40% are independent predictors of in-hospital mortality in left-sided native valve Staphylococcus aureus endocarditis 1
• Valve perforation on echocardiography is an independent predictor of 1-year mortality 1
• Increasing vegetation size or failure to decrease in size during antibiotic therapy predicts a prolonged or complicated course 1
• Other prognostic findings include periannular complications, severe valvular regurgitation, pulmonary hypertension, severe prosthetic valve dysfunction, and premature mitral valve closure 1

Special Considerations

Prosthetic Valve Endocarditis

• TEE is mandatory when prosthetic valve endocarditis is suspected due to its superior sensitivity (90% vs. 50% for TTE) 3, 4
• Acoustic shadowing from prosthetic materials can limit visualization, potentially requiring complementary imaging approaches 3, 5
• Valve dehiscence appears as excessive mobility of the prosthetic valve during the cardiac cycle 1

Timing of Echocardiography

• Early TEE may miss initial perivalvular abscesses, as they may initially appear only as nonspecific perivalvular thickening 4, 1
• If initial TEE is negative but clinical suspicion remains high, repeat TEE is recommended after 3-10 days 4, 1
• Incipient abscesses become more recognizable as they expand and develop cavities over several days 4, 1

Pitfalls and Limitations

• False negatives can occur if vegetations are small or have already embolized 4, 2
• TEE has up to 98.6% negative predictive value but cannot completely rule out infective endocarditis 3, 4
• Anterior prosthetic ring abscesses may be missed by TEE alone 3, 5
• Both TTE and TEE may produce false-negative results early in the disease course when pathological changes are still developing 4, 5

Recommended Imaging Algorithm

1. Initial assessment: Perform TTE as the first imaging study for all suspected cases of infective endocarditis 1, 5
2. High-risk patients: Proceed directly to TEE for patients with intermediate/high clinical suspicion, prosthetic valves, or cardiac devices 3, 5
3. Negative initial imaging: If initial imaging is negative but clinical suspicion remains high, repeat TEE after 3-10 days 4, 1
4. Follow-up imaging: Repeat echocardiography with new cardiac symptoms, persistent fever, or to assess response to therapy 1