Safely ruling out deep venous thrombosis in primary care

Area of Science:

• Vascular Medicine
• Diagnostic Accuracy
• Primary Care Medicine

Background:

• Deep venous thrombosis (DVT) is often suspected but infrequently confirmed in patients presenting for ultrasonography.
• High rates of negative DVT diagnoses lead to unnecessary referrals and healthcare costs.

Purpose of the Study:

• To assess the safety and efficiency of a primary care clinical decision rule incorporating a point-of-care d-dimer assay for excluding DVT.
• To determine if this strategy can safely reduce referrals to secondary care for DVT investigation.

Main Methods:

• A prospective management study involving 1028 patients with suspected DVT across 300 primary care practices in the Netherlands.
• Patients were assessed using a clinical decision rule with a d-dimer assay. Low-risk scores (≤3) led to no ultrasonography or anticoagulation; high-risk scores (≥4) prompted ultrasonography.
• The primary outcome was symptomatic, objectively confirmed venous thromboembolism within a 3-month follow-up period.

Main Results:

• In 500 patients with low-risk scores, 7 (1.4%) experienced venous thromboembolism within 3 months.
• Of 502 patients with high-risk scores, ultrasonography confirmed DVT in 125 (25%). Among 374 with normal ultrasonography, 4 (1.1%) developed venous thromboembolism.
• The diagnostic strategy reduced referrals for ultrasonography by nearly 50%.

Conclusions:

• A diagnostic strategy using a clinical decision rule and point-of-care d-dimer assay is safe and efficient in primary care for excluding DVT.
• This approach significantly decreases the need for secondary care referrals while maintaining a low risk of subsequent venous thromboembolic events.