What are the steps to assess infective endocarditis with Transthoracic Echocardiography (TTE), according to the American Society of Echocardiography (ASE) guidelines?

From the Guidelines

To assess endocarditis with transthoracic echocardiography (TTE) according to ASE guidelines, follow these steps: First, obtain comprehensive imaging of all cardiac valves using multiple views to identify vegetations, which appear as oscillating masses attached to valves or endocardial surfaces, as recommended by the 2021 ACR Appropriateness Criteria for infective endocarditis 1. The most recent and highest quality study, published in 2022, emphasizes the central role of echocardiography in evaluating patients with suspected infection of prosthetic devices and cardiac implantable electronic devices (CIEDs) 1. Key steps in the assessment include:

• Focus particularly on the left-sided valves (mitral and aortic) which are most commonly affected.
• Assess for valvular regurgitation using color Doppler, as new or worsening regurgitation may indicate endocarditis.
• Look for complications such as valve perforation, abscess formation, pseudoaneurysms, or fistulas, especially in the aortic root area.
• Measure vegetation size and mobility, as larger (>10 mm) and mobile vegetations carry higher embolic risk, as noted in the 2005 AHA guidelines for the diagnosis and treatment of infective endocarditis 1.
• Evaluate ventricular size and function to assess hemodynamic impact.
• Use harmonic imaging and optimize machine settings to enhance visualization of small vegetations.
• Document findings systematically, including vegetation location, size, mobility, and associated complications. If TTE results are negative but clinical suspicion remains high, transesophageal echocardiography (TEE) should be performed due to its superior sensitivity, particularly for prosthetic valves, device-related infections, and paravalvular complications, as recommended by the 2015 ESC guidelines for the management of infective endocarditis 1. Serial echocardiographic examinations may be necessary to monitor treatment response or disease progression, with the timing and mode (TTE or TEE) of repeat examination depending on the initial findings, type of microorganism, and initial response to therapy, as suggested by the 2021 ACR Appropriateness Criteria for infective endocarditis 1.

From the Research

Assessment of Endocarditis with TTE

According to the American Society of Echocardiography (ASE) guidelines, the following steps can be taken to assess endocarditis with Transthoracic Echocardiogram (TTE):

• Evaluate the patient's clinical presentation and medical history to determine the likelihood of endocarditis 2
• Perform a TTE to visualize the heart valves and check for signs of endocarditis, such as vegetations or abscesses 3, 2
• Assess the quality of the TTE images and determine if a Transesophageal Echocardiogram (TEE) is needed for further evaluation 4
• Use the modified Duke criteria to diagnose endocarditis, which includes factors such as positive blood cultures, evidence of endocardial involvement, and other clinical signs 5

Limitations of TTE

It is essential to note that TTE has limitations in diagnosing endocarditis, particularly in patients with prosthetic valves or complex valve disease 6. TEE may be necessary to provide more detailed images and accurate diagnosis 3, 4, 6.

Diagnostic Accuracy of TTE

Studies have shown that TTE has a sensitivity of 0.71 and specificity of 0.80 in diagnosing native valve infective endocarditis, with a negative likelihood ratio of 0.37 and positive likelihood ratio of 3.56 2. However, the diagnostic accuracy of TTE may vary depending on the patient population and the specific clinical scenario 2.