Should a Transthoracic Echocardiogram (TTE) be ordered for a hemodynamically stable patient with Pulmonary Embolism (PE)?

From the Guidelines

A transthoracic echocardiogram (TTE) should be ordered for hemodynamically stable patients with pulmonary embolism (PE) as it provides valuable information about right ventricular function and can help risk-stratify patients. According to the 2019 ESC guidelines on the diagnosis and management of acute pulmonary embolism 1, in a patient without haemodynamic instability, confirmation of PE must be followed by further risk assessment involving clinical findings and comorbidity along with evaluation of the size and/or function of the RV. The TTE can identify right ventricular dysfunction, which is associated with worse outcomes even in initially stable patients. Specific findings to look for include right ventricular dilation, hypokinesis, increased right ventricular to left ventricular ratio, tricuspid regurgitation, and pulmonary hypertension. These findings may influence management decisions, such as the need for more aggressive therapy or closer monitoring. For instance, patients with right ventricular dysfunction might benefit from hospitalization even if otherwise stable.

The use of TTE in acute cardiovascular care, including pulmonary embolism, is also supported by the European Association of Cardiovascular Imaging and the Acute Cardiovascular Care Association 1. Although the sensitivity of TTE for the diagnosis of pulmonary embolism is about 50–60% while the specificity is around 80–90%, it can provide direct and/or indirect evidence for the diagnosis. The main indirect findings for pulmonary embolism are the consequences of acutely increased pulmonary artery/right heart pressures, including dilatation of right heart chambers, RV hypokinesia, and abnormal motion of the interventricular septum.

In clinical practice, the TTE is non-invasive, readily available in most settings, and can be performed quickly at the bedside. Additionally, it may reveal alternative diagnoses if PE is not confirmed. While not all stable PE patients will have abnormal findings on TTE, the potential to identify those at higher risk for decompensation makes it a valuable tool in the comprehensive evaluation of these patients. Key points to consider when ordering a TTE for a hemodynamically stable patient with PE include:

• Evaluation of right ventricular function and size
• Assessment of tricuspid regurgitation and pulmonary hypertension
• Identification of alternative diagnoses
• Risk stratification to guide management decisions
• Consideration of hospitalization for patients with right ventricular dysfunction.

From the Research

Diagnosis and Treatment of Pulmonary Embolism

• The diagnosis and treatment of pulmonary embolism (PE) depend on the patient's hemodynamic stability and the presence of right ventricular dysfunction 2.
• Hemodynamically stable patients with suspected PE should undergo diagnostic evaluation, including clinical probability assessment, D-dimer levels, and imaging studies such as multidetector computed tomography (MDCT) or echocardiography 2.
• The use of transthoracic echocardiography (TTE) is recommended in patients with suspected PE and right ventricular dysfunction, as it can help identify patients at high risk of adverse outcomes 3, 4.

Role of TTE in PE Diagnosis

• TTE can detect right ventricular dysfunction, which is a predictor of poor outcomes in patients with PE 3, 4.
• The presence of right ventricular dysfunction on TTE can guide treatment decisions, including the use of thrombolytic therapy or anticoagulation 3, 2.
• However, the routine use of TTE in all patients with suspected PE is not recommended, and its use should be reserved for patients with high-risk features or those with suspected right ventricular dysfunction 2.

Treatment of Hemodynamically Stable Patients with PE

• Hemodynamically stable patients with PE should be treated with anticoagulation, which can be initiated with low-molecular-weight heparin or fondaparinux, and then transitioned to long-term oral anticoagulation with a vitamin K antagonist or a non-vitamin K antagonist oral anticoagulant (NOAC) 5, 6.
• The choice of anticoagulant and the duration of treatment should be individualized based on the patient's risk factors and the presence of right ventricular dysfunction 5, 6.