Pulmonary Embolism

Diagnosis

• 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

Treatment

• 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