What are the Wells criteria for Deep Vein Thrombosis (DVT)?

From the Guidelines

The Wells criteria for Deep Vein Thrombosis (DVT) is a clinical prediction rule that assigns points based on specific clinical features to assess the probability of DVT in patients with suspected symptoms. The criteria includes active cancer (treatment ongoing, within 6 months, or palliative) receiving 1 point; paralysis, paresis, or recent plaster immobilization of the lower extremities getting 1 point; recent bedridden status for more than 3 days or major surgery within 12 weeks getting 1 point; localized tenderness along the distribution of the deep venous system receiving 1 point; entire leg swelling getting 1 point; calf swelling by more than 3 cm compared to the asymptomatic leg getting 1 point; pitting edema confined to the symptomatic leg receiving 1 point; collateral superficial veins (non-varicose) getting 1 point; previously documented DVT receiving 1 point; and an alternative diagnosis at least as likely as DVT subtracting 2 points 1.

Key Points to Consider

• A score of ≥2 indicates that the probability of deep venous thrombosis is likely; a score of <2 indicates that the probability of deep venous thrombosis is unlikely 1.
• The Wells score has limitations, including interobserver reliability and performance in primary care settings 1.
• The criteria helps clinicians determine the appropriate next steps in management, such as whether to order D-dimer testing or proceed directly to ultrasound imaging.

Clinical Application

• The Wells criteria is valuable because it standardizes assessment and reduces unnecessary testing in patients with low probability of DVT.
• Clinicians should use the Wells criteria to categorize patients as low risk, moderate risk, or high risk for DVT, and proceed with management accordingly 1.

From the Research

Overview of Wells Criteria for DVT

The Wells criteria for Deep Vein Thrombosis (DVT) are a clinical prediction rule used to calculate the risk of DVT based on clinical criteria 2. This scoring system is designed to help clinicians assess the likelihood of DVT in patients and guide further diagnostic testing and treatment.

Components of the Wells Score

The Wells score includes several components that are associated with an increased risk of DVT, such as:

• Active cancer
• Paralysis or recent plaster immobilization of the lower extremities
• Recently bedridden for more than 3 days or major surgery within the last 12 weeks
• Local tenderness along the distribution of the deep venous system
• Entire leg swollen
• Calf swelling of more than 3 cm compared to the asymptomatic leg
• Pitting edema confined to the symptomatic leg
• Collateral superficial veins (non-varicose)
• Alternative diagnosis is less likely than DVT

Evaluation of the Wells Score

Studies have evaluated the usefulness of the Wells criteria in diagnosing DVT, with results showing that the score is useful in identifying patients at low risk of being diagnosed with venous thromboembolism 3. The addition of a rapid latex D-dimer assay has been shown to improve the overall performance of the prediction rule 3. The Wells score has also been shown to be reliable in trauma patients, with a linear correlation between the Wells score and the risk of DVT 4.

Clinical Application of the Wells Score

In clinical practice, the Wells score can be used to stratify patients into different risk categories, with those having a low score (<1) being at low risk of DVT and those with a higher score (≥2) being at moderate to high risk 4, 5. This can help guide further diagnostic testing, such as venous duplex scanning, and treatment, such as anticoagulation therapy. However, it is essential to note that the Wells score should be used in conjunction with other clinical factors and diagnostic tests to confirm the diagnosis of DVT.

Limitations and Future Directions

While the Wells score is a useful tool in diagnosing DVT, it has its limitations. Studies have shown that the prevalence of DVT in patients with a low, intermediate, or high Wells score may not correspond to the expected probabilities, highlighting the need for further validation and adjustment of the score for use in different clinical settings 5. Additionally, the integration of bleeding risk models into duration of therapy planning is an area that requires further research 6.

Key Points

• The Wells criteria are a clinical prediction rule used to calculate the risk of DVT based on clinical criteria.
• The score includes several components associated with an increased risk of DVT.
• The Wells score is useful in identifying patients at low risk of being diagnosed with venous thromboembolism.
• The score can be used to stratify patients into different risk categories and guide further diagnostic testing and treatment.
• The Wells score has its limitations and requires further validation and adjustment for use in different clinical settings. 2, 4, 3, 6, 5