Wells Criteria for Pulmonary Embolism

Purpose

• Assess the risk of a patient having a pulmonary embolism (PE).
• Determine next steps in diagnosis to rule in or rule out a PE.
• Used to decide whether a D-dimer test or CT angiography (CTA) is necessary.

Importance

• Essential in emergency room settings when immediate X-ray vision isn’t possible.
• Not all patients can safely or cost-effectively have a CTA.
• Relevant for exams like Step 2, Level 2, and internal medicine rotations.

Criteria Components and Scoring

1. Clinical Signs of Deep Vein Thrombosis (DVT)

   • Presence of calf pain and tenderness.
   • Yes = 3 points, No = 0 points.

2. Alternative Diagnosis Less Likely than PE

   • Subjective judgment if PE is the most likely diagnosis.
   • Yes = 3 points, No = 0 points.

3. Heart Rate > 100 bpm

   • Can indicate a PE.
   • Yes = 1.5 points, No = 0 points.

4. Recent Immobilization or Surgery

   • Immobilization in the past 72 hours or surgery in the last 4 weeks.
   • Yes = 1.5 points, No = 0 points.

5. History of DVT or PE

   • Past history increases risk.
   • Yes = 1.5 points, No = 0 points.

6. Hemoptysis

   • Coughing up blood.
   • Yes = 1 point, No = 0 points.

7. Malignancy

   • Current or treatment within the past 6 months, or in palliative care.
   • Yes = 1 point, No = 0 points.

Interpretation and Next Steps

• Score 0-4: PE Unlikely

  • Next step: D-dimer test (a simple blood test).
  • If D-dimer is positive, proceed to CTA.

• Score 5 or Greater: PE Likely

  • Skip D-dimer and go directly to CTA.
  • Research shows >20% of patients with high Wells score confirmed PE via CTA.

Memorization Tips

• "Angio" has 5 letters, thus a Wells score of 5 or more points directs to "Angio" (CTA).

Conclusion

• Wells Criteria helps differentiate the diagnostic pathway for suspected PE.
• Essential tool for clinical practice and exams to ensure the appropriate use of diagnostic resources.