RISK ASSESSMENT FOR PULMONARY EMBOLISM

RISK ASSESSMENT FOR PULMONARY EMBOLISM


1. Wells Score for Pulmonary Embolism

The Wells score is a clinical decision rule that estimates the probability of pulmonary embolism. The score is calculated based on clinical criteria:

  • Clinical signs and symptoms of deep vein thrombosis (3 points)
  • An alternative diagnosis is less likely than PE (3 points)
  • Heart rate > 100 bpm (1.5 points)
  • Immobilization for ≥3 days or surgery in the previous four weeks (1.5 points)
  • Previous DVT or PE (1.5 points)
  • Hemoptysis (1 point)
  • Malignancy (treatment for malignancy within the last six months, or palliative) (1 point)

The score is categorized as follows:

  • Low probability: <2 points
  • Moderate probability: 2-6 points
  • High probability: >6 points

2. Revised Geneva Score

The Revised Geneva Score uses objective criteria to assess the probability of PE, without relying on clinical judgment:

  • Age >65 years (1 point)
  • Previous DVT or PE (3 points)
  • Surgery or fracture within 1 month (2 points)
  • Active malignant condition (2 points)
  • Unilateral lower limb pain (3 points)
  • Hemoptysis (2 points)
  • Heart rate 75-94 bpm (3 points) or >95 bpm (5 points)
  • Pain on lower limb venous palpation and unilateral edema (4 points)

This score also classifies risk as low, intermediate, or high based on the total points.

3. Pulmonary Embolism Rule-out Criteria (PERC)

The PERC rule is used to rule out PE in patients with a low pre-test probability. If none of the following criteria are present, it is safe to conclude that the patient does not have PE:

  • Age <50 years
  • Heart rate <100 bpm
  • Oxygen saturation >94% on room air
  • No unilateral leg swelling
  • No hemoptysis
  • No recent trauma or surgery
  • No prior DVT or PE
  • No hormone use

4. Imaging and Laboratory Tests

  • D-dimer testing: Elevated D-dimer levels can indicate the presence of a clot, though not specifically for PE. This test is more useful for ruling out PE when the clinical probability is low.
  • CT pulmonary angiography (CTPA): This is the imaging test of choice for diagnosing PE when clinical suspicion is high.
  • Ventilation-perfusion (V/Q) scan: Used when CTPA is contraindicated or unavailable.

Decision Making

In clinical practice, the decision to further test or treat for PE is based on the combination of risk assessment scores, patient history, and initial test results. Treatment may involve anticoagulation therapy, and the intensity of treatment is guided by the assessed risk of PE and the patient’s overall health status.

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