Pulmonary Embolism


  • Although the majority of PE originates in the proximal deep veins of the leg, only 25-50% will have clinically-evident DVT at time of PE diagnosis
  • Provoking factors:
    • Active malignancy
    • Surgery (especially orthopedic)
    • Hospitalization
    • Air travel >8h
    • Hormone use/pregnancy
    • 50% unprovoked
  • Symptoms
    • Sudden onset dyspnea
    • Pleuritic chest pain
    • Syncope
  • Signs
    • Tachypnea, hypoxemia
    • Tachycardia, hypotension, RV dysfunction (distended jugular veins)
    • EKG (S1Q3T3)
  • Signs and symptoms of DVT

Clinical Decision Rules

  • Determine pre-test probability with Wells' Criteria
    • If low-pretest
      • Rule-out with PERC rule (excluded active cancer, thrombophilia, betablocker use, leg amputations, morbid obesity where leg swelling not easily determined)
        • Age ≥50
        • HR ≥100
        • SaO2 on RA <95%
        • Unilateral leg swelling
        • Hemoptysis
        • Recent surgery (≤4w requiring GA) or trauma
        • Prior PE or DVT
        • Hormone use (OCP, hormone replacement)
      • If low-pretest but cannot rule out with PERC, consider D-dimer
        • Negative D-dimer rules out PE
        • Positive D-dimer warrants further testing
          • Consider age>50 → use age x 10 as the cutoff
          • Consider adjusting threshold to clinical probability using YEARS Criteria, especially in pregnancy, consider PE ruled out
            • If 1 to 3 YEARS and D-dimer < 500 ng/mL
            • if no YEARS and D-dimer < 1000 ng/mL
    • If high pre-test
      • CT PA directly
      • V/Q in patients with normal CXR and no significant lung disease
        • Consider in renal failure, contrast allergy, young patients with normal CXR, pregnant women


  • Treat high pre-test while awaiting diagnostic imaging (unless high risk bleeding - eg, active bleeding or immediate postop)
    • Treatment can be withheld for 4h for intermediate, and 24h for low pre-test probability
  • Risk stratify with PESI model (outpatient vs. inpatient)
  • Anticoagulation for three months
    • DOAC preferred (or UFH if thrombolysis needed)
      • Rivaroxaban 15mg BID x 21d then 20mg PO daily (can consider decrease to 10mg PO daily after 6 months based on EINSTEIN CHOICE study)
      • Apixaban 10mg BID x 7d then 5mg PO BID (can consider decrease to 2.5mg PO BID after 6 months based on AMPLIFY Extend study)
    • Consider IVC if cannot be anticoagulated due to risks