What is the diagnostic workup for Pulmonary Embolism (PE)?

From the Guidelines

The diagnostic workup for Pulmonary Embolism (PE) should start with a clinical assessment and D-dimer test, followed by CT pulmonary angiography (CTPA) if the D-dimer is positive or clinical suspicion remains high, as recommended by the 2019 ESC guidelines 1.

Key Steps in PE Diagnostic Workup

• Start with a clinical assessment to determine the pre-test probability of PE
• Use a D-dimer test to rule out PE in patients with low pre-test probability, as it is highly sensitive but not specific 1
• If the D-dimer is positive or clinical suspicion remains high, proceed to CTPA, which is the gold standard for diagnosis 1
• If CTPA is contraindicated, consider a ventilation-perfusion (V/Q) scan as an alternative imaging test 1
• Obtain baseline labs, including complete blood count, basic metabolic panel, coagulation studies, and troponin, to evaluate for other potential causes of symptoms and to guide treatment
• Consider lower extremity duplex ultrasound to evaluate for deep vein thrombosis (DVT) if clinically indicated
• Assess hemodynamic stability and consider echocardiography if there's concern for right heart strain

Importance of Prompt Anticoagulation

• If PE is confirmed, initiate anticoagulation therapy immediately, unless the patient is bleeding or has absolute contraindications to this therapy 1
• Prompt anticoagulation is crucial to prevent clot propagation and reduce mortality risk

Additional Considerations

• Use recommended, validated diagnostic algorithms for PE, including standardized assessment of pre-test clinical probability and D-dimer testing, to avoid unnecessary imaging tests and exposure to ionizing radiation 1
• Consider the possibility of a false-positive finding if the CTPA report suggests single subsegmental PE, and discuss the findings with the radiologist and/or seek a second opinion to avoid misdiagnosis and unnecessary anticoagulation treatment 1

From the Research

Diagnostic Workup for Pulmonary Embolism (PE)

The diagnostic workup for Pulmonary Embolism (PE) involves a combination of clinical evaluation, risk stratification, and diagnostic tests. The following are the key components of the diagnostic workup:

• Clinical evaluation: A careful bedside evaluation is essential to estimate the clinical probability of PE 2.
• Risk stratification: Patients are stratified into low, moderate, or high risk based on their clinical probability of PE 2, 3.
• Diagnostic tests: The choice of diagnostic tests depends on the clinical probability of PE and may include:
  • D-dimer assay: Used to exclude PE in low-risk patients 2, 3.
  • Computed Tomography (CT) angiogram: The initial imaging study of choice for stable patients 3.
  • Ventilation-Perfusion (V/Q) scans: Used when CT is not available or if the patient has a contraindication to CT scans or intravenous contrast 3.
  • Echocardiography: Used to assess right ventricular dysfunction in patients with suspected massive PE 4, 3.
  • Pulmonary angiography: Remains the 'gold standard' for diagnosis, but is not always necessary 4.
• Diagnostic algorithms: Several diagnostic algorithms have been proposed to guide the diagnostic workup for PE, including those for patients with critical and non-critical clinical conditions 5.

Special Considerations

• High pretest probability: Patients with high pretest probability of PE may require more aggressive workup beyond imaging alone, as negative CT pulmonary angiography (CTPA) and negative D-dimer may not be sufficient to rule out PE 6.
• Massive PE: Patients with suspected massive PE require immediate attention and may benefit from thrombolytic therapy 4, 3.
• Submassive PE: Patients with submassive PE, characterized by right ventricular dysfunction, may benefit from thrombolytic therapy, but the use of thrombolysis in this group remains controversial 4.