From the Guidelines
Pulmonary embolism (PE) diagnosis should be approached with a clinical assessment using tools like the Wells score or PERC rule to determine pre-test probability, followed by D-dimer blood testing for low-risk patients, and CT pulmonary angiography (CTPA) for moderate to high-risk patients. The signs and symptoms of PE are non-specific and can include sudden shortness of breath, chest pain that worsens with deep breathing or coughing, rapid or irregular heartbeat, lightheadedness, and coughing that may produce bloody sputum 1. According to the American College of Physicians, clinicians should not obtain d-dimer measurements or imaging studies in patients with a low pretest probability of PE and who meet all Pulmonary Embolism Rule-Out Criteria 1.
Key Diagnostic Approaches
- For patients with an intermediate pretest probability of PE or in patients with low pretest probability of PE who do not meet all Pulmonary Embolment Rule-Out Criteria, a high-sensitivity d-dimer measurement should be obtained as the initial diagnostic test 1.
- Age-adjusted d-dimer thresholds (age × 10 ng/mL rather than a generic 500 ng/mL) should be used in patients older than 50 years to determine whether imaging is warranted 1.
- Imaging with CT pulmonary angiography (CTPA) should be obtained in patients with high pretest probability of PE, reserving ventilation–perfusion scans for patients who have a contraindication to CTPA or if CTPA is not available 1.
Importance of Prompt Diagnosis
Prompt diagnosis of PE is crucial as untreated PE can be life-threatening, with mortality rates significantly reduced when treatment is initiated early. The use of clinical decision tools and diagnostic testing strategies as outlined by the American College of Physicians can help guide clinicians in the evaluation of patients with suspected acute PE, ultimately improving patient outcomes 1.
From the Research
Signs and Symptoms of Pulmonary Embolism
- Sudden dyspnea (shortness of breath) 2
- Chest pain 3, 2
- Limb swelling 2
- Syncope (fainting) 3, 2
- Hemoptysis (coughing up blood) 3, 2
- Hypoxia (low oxygen levels) 4
- Tachypnea (rapid breathing) 4
- Tachycardia (rapid heart rate) 4
Diagnosis of Pulmonary Embolism
- Clinical assessment and objective diagnostic testing 5
- Clinical decision rule to determine pre-test probability of PE 5
- D-dimer testing to rule out PE in patients with low pre-test probability 3, 5, 4
- Chest imaging, such as computed tomography pulmonary angiogram (CTPA) or ventilation-perfusion (VQ) scan, to confirm diagnosis 3, 5, 4
- Risk stratification using tools like Wells score, Pulmonary Embolism Severity Index, and Hestia criteria to guide treatment decisions 2
Diagnostic Criteria
- A clinical probability of PE less than 15% can be used to identify patients at very low risk of PE, in whom no further testing is needed 3
- A D-dimer level of less than 500 ng/mL is associated with a post-test probability of PE less than 1.85% in patients with low or intermediate clinical probability 3
- Patients with a high probability of PE (ie, >40% probability) should undergo chest imaging, and D-dimer testing is not necessary 3
Imaging Modalities
- Computed tomography pulmonary angiogram (CTPA) is accurate and preferred for diagnosing PE, but may detect asymptomatic PE of uncertain clinical significance 5
- Ventilation-perfusion (VQ) scan is associated with lower radiation exposure than CTPA and may be preferred in younger patients and pregnancy 5