Transesophageal Echocardiography Can Be False Negative Early in Endocarditis
Yes, a transesophageal echocardiogram (TEE) can definitely be false negative early in the course of infective endocarditis, particularly when perivalvular complications are developing or when vegetations are small or have embolized. 1
Limitations of Early TEE in Endocarditis
- Even TEE may miss initial perivalvular abscesses, particularly when performed early in the patient's illness 1
- Incipient abscesses may initially appear only as nonspecific perivalvular thickening, which becomes more recognizable as they expand and develop cavities over several days 1
- Perivalvular fistulas and pseudoaneurysms develop over time, and negative early TEE images do not exclude their potential development 1
- Both TEE and TTE may produce false-negative results if vegetations are small or have already embolized 1
- Vegetation size significantly impacts detection - smaller vegetations (<5mm) are more likely to be missed even with TEE 2
Recommended Approach When Initial TEE is Negative
When clinical suspicion of IE remains despite a negative initial TEE:
- Repeat TEE is recommended 3-5 days after an initial negative result if clinical suspicion persists 1
- In the 2005 AHA guidelines, the recommendation was to repeat TEE 7-10 days after an initial negative result 1
- The rationale for repeating TEE is that vegetations may reach a detectable size in the interval, or abscess cavities or fistulous tracts may become evident 1
Risk Factors for False Negative TEE
Certain patient characteristics increase the risk of a false negative TEE:
- Prosthetic valves, particularly in the aortic position 3
- Gram-positive bacteremia 3
- Early stage of infection before vegetations have grown to detectable size 2
- Recent embolization of vegetations 1
Improving Diagnostic Accuracy
- Contemporary TEE technology has significantly improved diagnostic performance compared to older equipment, with sensitivity increasing from 85.7% in 2011 to 95.3% in 2019 4
- The improvement is particularly notable for prosthetic valve endocarditis detection, with sensitivity increasing from 70.8% to 93.7% 4
- Higher frame rates and 3D technology have contributed to improved detection capabilities 4
- One approach to minimizing confusion from normal structures is to exploit high frame rates available with current equipment to improve temporal resolution 1
Clinical Implications
- A negative TEE reduces but does not eliminate the likelihood of endocarditis, especially early in the disease course 3
- In patients with high clinical suspicion despite a negative initial TEE, empiric antibiotic therapy may still be warranted while awaiting repeat imaging 1
- Unexplained progression of heart failure symptoms, change in cardiac murmurs, and new atrioventricular block or arrhythmia should prompt repeat TEE even if the initial study was negative 1
Remember that while TEE is significantly more sensitive than TTE for detecting vegetations and abscesses, its sensitivity is not 100%, especially early in the disease course when pathological changes are still developing 1, 5.