Workup for Chest Pain Concerning for Pulmonary Embolism
The workup for a patient with chest pain concerning for pulmonary embolism should follow a structured approach beginning with clinical probability assessment, D-dimer testing if indicated, and chest imaging (primarily CT pulmonary angiography) if warranted by clinical probability or D-dimer results. 1
Initial Clinical Assessment
Clinical Probability Assessment
- Use validated clinical prediction rules to determine pre-test probability:
Very Low Risk Assessment
- In patients with probability of PE <15%, no further testing is needed if ALL of these 8 characteristics are present 3:
- Age <50 years
- Heart rate <100/min
- Oxygen saturation >94%
- No recent surgery or trauma
- No prior venous thromboembolism
- No hemoptysis
- No unilateral leg swelling
- No estrogen use
Laboratory Testing
D-dimer Testing
- Indicated for patients with low or intermediate clinical probability 1
- A negative D-dimer (<500 ng/mL) in low/intermediate probability patients can safely exclude PE without further imaging 3
- Age-adjusted D-dimer threshold (age × 10 ng/mL) can be used for patients ≥50 years 3
- Not necessary in high probability patients (>40% probability) who should proceed directly to imaging 3
- Limited value in pregnant, postoperative, and trauma patients 1
Other Laboratory Tests
- Arterial blood gas analysis (may show hypoxemia and hypocapnia) 1
- Cardiac biomarkers (troponin, BNP) to assess for RV dysfunction and risk stratification 2
- Complete blood count, basic metabolic panel, coagulation studies
Imaging Studies
Chest X-ray
- First-line imaging to exclude alternative diagnoses (pneumonia, pneumothorax, etc.) 1
- Often abnormal but findings are non-specific for PE 1
- Required before V/Q scanning to allow accurate interpretation 1
CT Pulmonary Angiography (CTPA)
- Primary imaging modality for evaluating suspected PE 1
- High sensitivity and specificity for detecting PE in central and segmental pulmonary arteries 1
- Can identify alternative diagnoses for chest pain 1
Ventilation/Perfusion (V/Q) Scan
- Alternative when CTPA is contraindicated (renal insufficiency, contrast allergy) 1
- A normal perfusion scan effectively excludes PE 1
- Most useful when chest X-ray is normal 1
Echocardiography
- Indicated immediately in patients with shock or hypotension 2
- Evaluates for right ventricular dysfunction and strain 2
- Findings suggestive of PE:
- RV dilation and hypokinesis
- Interventricular septal flattening
- 60/60 sign (pulmonary acceleration time <60 ms with tricuspid regurgitation pressure gradient <60 mmHg) 2
ECG
- Limited diagnostic value due to low sensitivity and specificity 2
- May show:
- S1Q3T3 pattern (sensitivity 11-50%, specificity >90%)
- T-wave inversions in leads V1-V4
- Right bundle branch block
- Sinus tachycardia
- Non-specific ST-segment and T-wave changes 2
Management Based on Hemodynamic Status
Hemodynamically Stable Patients
Hemodynamically Unstable Patients
- Immediate echocardiography 2
- Consider immediate anticoagulation with IV heparin bolus (80 units/kg) 2
- Transfer to centers with advanced capabilities (ICU with thrombectomy capabilities) 2
- Consider thrombolysis if deteriorating or in cardiac arrest 2
Common Pitfalls to Avoid
- Relying solely on clinical presentation (symptoms are non-specific) 1
- Waiting for all test results before starting anticoagulation in high-risk patients 2
- Overlooking PE in patients with atypical presentations (syncope, angina-like symptoms) 4
- Misinterpreting imaging studies due to technical factors or anatomic variants 5
- Failing to adjust D-dimer thresholds for age in older patients 3
By following this structured approach, clinicians can effectively diagnose or exclude PE while minimizing unnecessary testing and treatment delays that could impact patient outcomes.