When is a Transesophageal Echocardiogram (TEE) recommended in patients with gram-positive bacteremia?

From the Guidelines

A Transesophageal Echocardiogram (TEE) is recommended in patients with gram-positive bacteremia when there is a high suspicion for infective endocarditis, particularly in Staphylococcus aureus bacteremia, persistent bacteremia despite appropriate antibiotics, bacteremia with no clear source, or when a transthoracic echocardiogram (TTE) is inadequate or negative despite strong clinical suspicion. This recommendation is based on the most recent and highest quality study available, which emphasizes the importance of TEE in diagnosing and managing infective endocarditis 1.

Key Indications for TEE

• High suspicion for infective endocarditis
• Staphylococcus aureus bacteremia
• Persistent bacteremia despite appropriate antibiotics
• Bacteremia with no clear source
• Inadequate or negative TTE despite strong clinical suspicion
• Presence of prosthetic heart valves, intracardiac devices, congenital heart disease, or previous history of endocarditis

Benefits of TEE

• Superior sensitivity (90-95%) compared to TTE (40-60%) for detecting vegetations, perivalvular abscesses, and other complications of endocarditis
• Ability to obtain high-resolution images of cardiac structures without interference from chest wall or lung tissue
• Ideal for patients with complex cardiac anatomy or those at high risk of complications

Timing of TEE

• Ideally performed within 5-7 days of bacteremia diagnosis, after patients have received initial antibiotic therapy but before potential vegetations have been sterilized
• Repeat TEE may be necessary if clinical suspicion of IE persists or if new complications arise

Clinical Considerations

• TEE should be considered in patients with clinical signs of endocarditis, such as new murmurs, embolic phenomena, or heart failure
• The procedure involves passing an ultrasound probe into the esophagus, which may require sedation and monitoring
• Results of TEE should be interpreted in the context of clinical presentation and other diagnostic findings.

From the Research

Recommendations for Transesophageal Echocardiogram (TEE) in Gram-Positive Bacteremia

• A TEE is recommended in patients with gram-positive bacteremia who have a high risk of infective endocarditis (IE), such as those with intracardiac prosthetics or persistent fever despite appropriate antibiotic therapy 2.
• The American Society of Echocardiography (ASE) has developed appropriate use criteria for TEE, which outline various scenarios where a TEE is indicated as an initial diagnostic testing modality or as an adjunctive test 3.
• Patients with Staphylococcus aureus bacteremia (SAB) should undergo TEE when possible to detect evidence of IE, especially if the results might affect management 4.
• A scoring system, such as the modified Palraj's score, can be used to guide the use of TEE in patients with SAB, taking into account factors such as intravenous drug abuse, cardiac devices, and prolonged bacteremia 5.

Risk Factors for Infective Endocarditis

• The presence of cardiac devices, such as permanent pacemakers, increases the risk of IE in patients with gram-positive bacteremia 2.
• Persistent fever despite appropriate antibiotic therapy is also a risk factor for IE in these patients 2.
• Other risk factors for IE include intravenous drug abuse, prolonged bacteremia, and the presence of prosthetic valves 5.

Diagnostic Modalities for Infective Endocarditis

• Echocardiography, including TEE, is the cornerstone of IE investigations 6.
• Other diagnostic modalities, such as 18F-fluorodesoxyglucose positron emission tomography/computed tomography and cardiac computed tomography, may also be used in certain cases 6.
• A flowchart can be used to suggest which investigations to perform in relation to IE in patients with gram-positive bacteremia, taking into account individual patient risk factors and clinical presentation 6.