Echocardiographic Findings in Infective Endocarditis

Primary Echocardiographic Findings

• Vegetations are the hallmark finding in infective endocarditis and appear as mobile, echogenic masses attached to valvular structures 1, 2
• Vegetation size, mobility, and location are critical characteristics that help predict complications and guide management 2, 3
• Large vegetations (>10 mm) on the anterior mitral leaflet carry the highest risk for peripheral embolization 4, 5
• Valvular destruction with resultant regurgitation is a common finding 2, 3
• Valve perforation appears as interruptions in valve tissue continuity with abnormal flow on color Doppler 6
• Valve dehiscence, particularly in prosthetic valves, manifests as excessive mobility of the valve during the cardiac cycle 1, 6

Perivalvular Complications

• Paravalvular abscesses appear as thickened, non-homogeneous perivalvular areas with echodense or echolucent appearance 6, 5
• Pseudoaneurysms present as pulsatile perivalvular echo-free spaces with flow detected on color Doppler 6, 4
• Fistulous tracts may develop between cardiac chambers or vascular structures 6, 5

Comparative Diagnostic Accuracy

• TTE has approximately 75% sensitivity for detecting vegetations, which increases to 85-90% with TEE 6, 7
• TEE demonstrates approximately 99% sensitivity for native valve endocarditis, significantly outperforming TTE 7, 2
• For prosthetic valve endocarditis, TEE has approximately 90% sensitivity compared to only 50% for TTE 7, 8

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 2, 5
• Valve perforation on echocardiography is an independent predictor of 1-year mortality 2, 3
• Increasing vegetation size or failure to decrease in size during antibiotic therapy predicts a prolonged or complicated course 3, 5

Special Considerations

• TEE is mandatory when prosthetic valve endocarditis is suspected due to its superior sensitivity (90% vs. 50% for TTE) 7, 8
• Acoustic shadowing from prosthetic materials can limit visualization, potentially requiring complementary imaging approaches 7, 9
• Valve dehiscence appears as excessive mobility of the prosthetic valve during the cardiac cycle 1, 6

Recommended Imaging Algorithm

• Initial assessment: Perform TTE as the first imaging study for all suspected cases of infective endocarditis 2, 9
• High-risk patients: Proceed directly to TEE for patients with intermediate/high clinical suspicion, prosthetic valves, or cardiac devices 7, 9
• Negative initial imaging: If initial imaging is negative but clinical suspicion remains high, repeat TEE after 3-10 days 8, 4
• Follow-up imaging: Repeat echocardiography with new cardiac symptoms, persistent fever, or to assess response to therapy 4, 3

Echocardiography in Candidemia for Detection of Candida Infective Endocarditis

Epidemiology and Clinical Impact

• Candida infective endocarditis (CIE) occurs in approximately 4–6 % of patients with candidemia and is frequently clinically unsuspected, underscoring the need for systematic cardiac imaging. 10
• Fungal endocarditis carries the highest mortality among all causes of infective endocarditis, with 90‑day mortality approaching 48.9 %. 11

Guideline Recommendations for Imaging

• All patients with candidemia should undergo echocardiographic evaluation to detect cardiac vegetations. 10
• Transesophageal echocardiography (TEE) is recommended to assess organ involvement in candidemic patients. 10
• Both transthoracic echocardiography (TTE) and TEE are advised as complementary investigations, with TEE providing superior sensitivity. 12
• Echocardiography is fundamental for identifying cardiac complications in patients with candidemia and/or disseminated candidiasis. 13

Diagnostic Performance of TTE vs. TEE

• TTE is the first‑line imaging modality for all candidemic patients; its sensitivity for detecting vegetations is ≈ 75 %, identifying only a small fraction of CIE cases in prospective data. 14
• TEE demonstrates a positivity rate of ≈ 11.5 % among candidemic patients who undergo the study, markedly higher than TTE. 14
• TEE sensitivity for vegetations ranges from 85–90 %, reaching ≈ 99 % for native‑valve endocarditis. 14
• In patients with prosthetic valves or cardiac devices, TEE sensitivity is about 90 % versus 50 % for TTE. 14

Timing and Clinical Triggers for Imaging

• Echocardiography should be performed as soon as candidemia is documented, ideally within 24–48 hours. 10
• Antifungal therapy must not be delayed while awaiting echocardiography. 10
• Immediate TEE is indicated for patients with any of the following high‑risk features:
  
  • Persistent candidemia despite appropriate antifungal therapy. 10
  • New cardiac murmur or signs of heart failure. 11
  • Pre‑existing valvular heart disease (adjusted OR ≈ 7.66 for CIE). (risk estimate cited in source, no specific reference)
  • Prosthetic valves or cardiac devices.

Management Implications of Positive Findings

• First‑line antifungal therapy for confirmed CIE should be an echinocandin (e.g., micafungin, caspofungin, or anidulafungin). 10
• Early consultation with cardiothoracic surgery is recommended for consideration of valve or device replacement, as medical therapy alone is associated with high mortality. 11
• Antifungal treatment duration should be extended to at least 4–6 weeks, including a minimum of 2 weeks after removal of any infected device or valve. 12
• A bedside fundoscopy should be performed to screen for ocular candidiasis as part of the comprehensive assessment. 10

Echocardiographic Reporting Standards for Infective Endocarditis

Diagnostic Features

• Vegetations—mobile, echogenic masses attached to valve leaflets or mural endocardium—are the hallmark echocardiographic finding and carry primary diagnostic weight in the modified Duke criteria for infective endocarditis. 15, 16, 17
• Vegetation size > 10 mm is associated with a high risk of embolic events and should be explicitly measured. 18, 19
• Vegetations located on the anterior mitral leaflet confer the greatest embolic risk. 18, 19
• The attachment site (valvular leaflet versus mural endocardium) must be documented. 15, 16

Valvular Complications

• Acute aortic or mitral regurgitation (degree and mechanism) should be reported, as it reflects severe valve dysfunction. 18, 19
• Valve rupture is a critical complication that requires clear description. 18, 19
• Prosthetic‑valve dehiscence (excessive mobility on color Doppler) must be noted; it often mandates further evaluation with transesophageal echocardiography (TEE). 15, 18, 19

Perivalvular Extension

• Perivalvular abscesses appear as thickened, non‑homogeneous perivalvular areas with echodense or echolucent components and should be identified. 18, 16, 19
• Fistulous tracts (abnormal communications between cardiac chambers) are important perivalvular complications to describe. 18, 19

Imaging Sensitivity & Recommendations

• Transthoracic echocardiography (TTE) detects vegetations in native‑valve endocarditis with a sensitivity of approximately 70–75 %. 15, 16
• When TTE does not clearly visualize vegetations but clinical suspicion remains high, a TEE should be recommended for definitive assessment. 18, 16
• In prosthetic‑valve endocarditis, TTE sensitivity falls to about 50 %; therefore, TEE is mandatory for accurate evaluation even if TTE is negative. 15, 18, 19

Hemodynamic Assessment

• The severity of valvular regurgitation or stenosis must be quantified in the report. 15, 16
• Signs of ventricular decompensation or heart failure should be documented. 15, 16

Reporting Standards & Pitfalls

• Vague language (e.g., “possible vegetation”) should be avoided; reports must provide specific findings and, when non‑diagnostic, a clear recommendation for TEE. 15, 18, 16
• For negative TTE studies in the setting of high clinical suspicion, repeat TEE in 3–5 days is advised, as small vegetations or early abscesses may become detectable later. 18, 19

Prognostic Indicators for Surgical Consideration

• Vegetation size > 10 mm combined with embolic events predicts the need for surgical intervention. 18, 19
• An increase in vegetation size despite appropriate antimicrobial therapy signals a higher likelihood of surgery. 18, 19
• Acute severe regurgitation accompanied by heart failure is a surgical indication. 18, 19
• Large or expanding perivalvular abscesses warrant surgical management. 18, 19