What Do the Guidelines Say?

Three sets of recommendations have been published in the past 2 years :

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  An American Heart Association scientific statement on IE in adults was published in 2015. The role of echocardiography is very well detailed, and the recommendations are the following:

  
  
  
  
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    TTE should be performed in all cases of suspected IE (Class I, Level of Evidence B).

    
    
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    TEE should be done if initial transthoracic images are negative or inadequate in patients in whom there is ongoing suspicion for IE or when there is concern for intracardiac complications in patients with initial positive results on TTE (Class I, Level of Evidence B).

    
    
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    In addition, patients are separated into high and low initial risk:

    
    
    
    
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      In patients at high initial risk, those with moderate to high clinical suspicion, or difficult imaging candidates, initial TTE, followed by TEE as soon as possible, is recommended.

      
      
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      In patients at low initial risk with low clinical suspicion, initial TTE is proposed, and if the results are negative, TEE is recommended only if increased suspicion appears during the clinical course.

      
      
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      In the same category of patients, but with positive results on TTE, TEE is recommended for the detection of complications only with high-risk echocardiographic features or if clinical status deteriorates.

    
    
    
    
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    In all cases, the need for an early echocardiographic evaluation is underlined. If any circumstances preclude the securing of optimal echocardiographic windows, including chronic obstructive lung disease, previous thoracic or cardiovascular surgery, morbid obesity, or other conditions, TEE should be performed as soon as possible after TTE.

  
  
  
  
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  The 2014 American Heart Association and American College of Cardiology guideline for the management of patients with valvular heart disease also focuses on the diagnosis of IE and gives the following recommendations:

  
  
  
  
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    TTE is recommended in patients with suspected IE to identify vegetations, characterize the hemodynamic severity of valvular lesions, assess ventricular function and pulmonary pressures, and detect complications (Class I, Level of Evidence B).

    
    
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    TEE is recommended in all patients with known or suspected IE when TTE is nondiagnostic, when complications have developed or are clinically suspected, and when intracardiac device leads are present (Class I, Level of Evidence B).

  
  
  
  
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  The 2015 European Society of Cardiology guidelines for the management of IE make the following recommendations:

  
  
  
  
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    TTE is recommended as the first-line imaging modality in suspected IE (Class I, Level of Evidence B).

    
    
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    TEE is recommended in all patients with clinical suspicion of IE and negative or nondiagnostic results on TTE (Class I, Level of Evidence B).

    
    
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    TEE should be considered in patients with suspected IE, even in those with positive results on TTE, except in isolated right-sided native valve IE with good-quality transthoracic examination and unequivocal echocardiographic findings (Class IIa, Level of Evidence C).

  
  

Finally, apart from the proposal in the European guidelines to perform TEE even when the results of TTE are positive, all three recent recommendations agree on the following main conclusions:

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  Echocardiography should be performed as soon as possible.

  
  
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  TTE should be performed first.

  
  
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  TEE should be performed when TTE is of lower quality or when the results of TTE are inconclusive.