Curriculum · Cardiovascular and Hypertension
Choosing between transthoracic and transoesophageal echocardiography in suspected endocarditis
What the choice is
In suspected infective endocarditis the echocardiogram is what carries the evidence of endocardial involvement, and there are two of them: transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE). The order is not free. TTE is the initial test of choice for all patients with suspected IE, and TEE is where a negative or poor quality TTE is taken next, in a defined set of patients.
Where TTE stands
A normal TTE, meaning normal valve structure and function and no mobile mass, is reasonably sensitive for native valve endocardial involvement. TTE is generally sufficient when the probability of endocarditis is low on clinical suspicion, and it is put at 75% sensitive. That is why it is the first test in patients other than the ones singled out below.
When TEE instead
TEE should be considered when the TTE is negative and any of these is present: a prosthetic valve, high suspicion of endocarditis, persistently positive cultures, prior valve abnormalities, poor quality TTE, or bacteria known to cause endocarditis such as S. aureus and viridans. The same list is given from the other side as the high likelihood of endocarditis, where TEE is 90-95% sensitive: preexisting valve disease, positive blood cultures, suspected prosthetic valve endocarditis, and intracardiac devices such as a pacemaker. Inside the criteria themselves the same rule is written out in three: 1. TEE is recommended in patients with prosthetic valves; 2. in patients rated at least possible IE by clinical criteria; 3. in complicated IE with a paravalvular abscess. TTE is the first test in other patients.