What is the role of Well's score and Geneva score in diagnosing pulmonary embolism (PE)?

Role of Well's Score and Geneva Score in Diagnosing Pulmonary Embolism

Both the Wells score and Geneva score are validated clinical prediction rules that help stratify patients with suspected pulmonary embolism (PE) into risk categories, but the Wells score demonstrates superior diagnostic accuracy and should be preferred in most clinical settings. 1

Clinical Decision Rules Overview

Clinical decision rules are essential tools in the evaluation of suspected PE as they:

1. Standardize assessment of pretest probability
2. Guide appropriate use of diagnostic testing
3. Help avoid unnecessary imaging
4. Reduce patient exposure to radiation and contrast
5. Decrease healthcare costs

Wells Score

The Wells score is widely used and includes both objective criteria and subjective clinical judgment:

Variable	Points
Clinical signs and symptoms of DVT	3.0
PE is #1 diagnosis OR equally likely	3.0
Heart rate > 100	1.5
Immobilization ≥ 3 days or surgery in previous 4 weeks	1.5
Previous DVT/PE	1.5
Hemoptysis	1.0
Malignancy (treatment within 6 months or palliative)	1.0

Risk Stratification:

• Traditional interpretation:
  • Low risk: 0-1 points (3.6% PE prevalence)
  • Intermediate risk: 2-6 points (20.5% PE prevalence)
  • High risk: >6 points (66.7% PE prevalence)
• Dichotomized interpretation:
  • PE unlikely: 0-4 points (7.8% PE prevalence)
  • PE likely: >4 points (40.7% PE prevalence)

Geneva Score (Revised and Simplified)

The Geneva score is fully standardized and based entirely on objective variables:

Variable	Revised Geneva Points	Simplified Revised Geneva Points
Age > 65 years	1	1
Previous DVT/PE	3	1
Surgery/fracture within past month	2	1
Active cancer	2	1
Unilateral lower-limb pain	3	1
Hemoptysis	2	1
Heart rate 75-94 bpm	3	1
Heart rate ≥ 95 bpm	5	2
Pain on lower-limb deep venous palpation and unilateral edema	4	1

Risk Stratification:

• Traditional interpretation (Revised Geneva):
  • Low risk: 0-3 points (7.9% PE prevalence)
  • Intermediate risk: 4-10 points (28.5% PE prevalence)
  • High risk: 11-25 points (73.7% PE prevalence)
• Simplified Revised Geneva:
  • Low risk: 0-1 points (7.7% PE prevalence)
  • Intermediate risk: 2-4 points (29.4% PE prevalence)
  • High risk: 5-7 points (64.3% PE prevalence)
  • Alternative dichotomized: PE unlikely (0-2 points, 12.9% PE prevalence) vs. PE likely (3-7 points, 41.6% PE prevalence)

Comparative Performance

Multiple studies have compared these scoring systems:

• A meta-analysis showed the Wells score (AUC 0.778) was significantly more accurate than the revised Geneva score (AUC 0.693) for predicting PE 1
• The Wells score performs particularly better in patients with high suspicion of PE 2
• The Wells score demonstrated higher specificity (67.5% vs 47.0%) compared to the Geneva score, which could reduce unnecessary imaging 3
• The simplified Geneva score has similar efficiency and safety to the original Geneva score when used with D-dimer testing 4

Clinical Application Algorithm

1. Initial Assessment:

   • Apply either Wells or Geneva score (preferably Wells due to superior accuracy)
   • Determine risk category (low, intermediate, high)

2. For Low-Risk Patients:

   • Wells score 0-1 or Geneva score 0-3
   • Measure D-dimer
   • If D-dimer negative: PE excluded (safe to stop investigation)
   • If D-dimer positive: Proceed to imaging (CTPA or V/Q scan)

3. For Intermediate-Risk Patients:

   • Wells score 2-6 or Geneva score 4-10
   • Measure D-dimer
   • If D-dimer negative: PE excluded (safe to stop investigation)
   • If D-dimer positive: Proceed to imaging

4. For High-Risk Patients:

   • Wells score >6 or Geneva score >10
   • Proceed directly to imaging without D-dimer testing

5. Age Adjustment for D-dimer:

   • For patients >50 years: Consider age-adjusted D-dimer cutoff (age × 10 μg/L) to improve specificity 5

Important Considerations and Pitfalls

• Interrater Reliability: The Wells score has moderate interrater reliability for some subjective elements like "PE as most likely diagnosis" 5
• Clinical Experience: The Geneva score shows more consistent results regardless of clinician experience level 5
• Memorization: Simplified versions of both scores were developed to improve clinical adoption 5
• Patient Selection: Both scores perform best when applied to patients with genuine clinical suspicion of PE, not as universal screening tools 5
• Inpatient vs. Outpatient: D-dimer specificity is lower in inpatients due to comorbidities, but still appropriate as an initial step when combined with risk stratification 5
• PERC Rule: For very low-risk patients, consider using the Pulmonary Embolism Rule-Out Criteria (PERC) to avoid even D-dimer testing 5

Conclusion

Both the Wells and Geneva scores are validated tools for PE risk stratification, but the Wells score demonstrates superior overall diagnostic accuracy. The choice between them should consider the clinical setting, with the Wells score generally preferred for its better performance, particularly in high-risk patients. Combining either score with appropriate D-dimer testing provides a safe and efficient approach to diagnosing or excluding PE while minimizing unnecessary imaging.