Diagnostic Approach to Suspected Pulmonary Embolism

Clinical Probability Assessment and D-dimer Testing

• The European Society of Cardiology recommends always beginning with assessment of clinical probability using validated tools like Wells score or Geneva score, or clinician gestalt 1, 2, 3
• Clinical probability stratification is the essential first step that determines subsequent testing strategy, as recommended by the American College of Physicians 2, 4

D-dimer Interpretation and Imaging

• For patients with low clinical probability, if they meet all PERC criteria, no D-dimer testing or imaging is needed, according to the European Heart Journal 3, 6
• For patients >50 years old, the American College of Cardiology recommends using age-adjusted D-dimer thresholds (age × 10 ng/mL) rather than fixed 500 ng/mL cutoff 2, 4, 8
• If D-dimer is below the appropriate threshold (standard or age-adjusted), PE can be safely excluded without imaging, as stated by the American College of Physicians 4, 6

Important Considerations for D-dimer Testing

• D-dimer has high negative predictive value but poor positive predictive value for PE, as noted by the European Heart Journal 1, 6
• The specificity of D-dimer decreases steadily with age, dropping to only 10% in patients >80 years, according to the European Heart Journal 8

Common Pitfalls to Avoid in PE Diagnosis

• Proceeding directly to CTPA with elevated D-dimer but low clinical suspicion leads to unnecessary radiation exposure and contrast risks, as warned by the European Heart Journal and the American College of Physicians 1, 7
• Ignoring clinical assessment when D-dimer is elevated is not recommended, as D-dimer elevation alone is not diagnostic of PE, according to the European Heart Journal 6