Management studies using a combination of D-dimer test result and clinical probability to rule out venous thromboembolism: a systematic review

Background: While the number of patients with Suspected venous thromboembolism (VTE) referred to hospital emergency units increases, the proportion in whom the diagnosis can be confirmed is decreasing. A more efficient but safe diagnostic strategy is needed. Objective: To evaluate the safety of withholding anticoagulant therapy ill patients suspected of VTE based oil a diagnostic work-Up that combines a clinical decision rule (CDR) with a D-dimer test result without performing additional diagnostic tests. Patients/methods: We searched Medline (January 1996-December 2004)related articles and reference lists Of Studies in English for prospective clinical Studies that managed Consecutive patients suspected of VTE and used a D-dimer assay combined with all explicit CDR or implicit clinical judgment. Results: We identified 11 studies in which 6837 Consecutive outpatients Suspected of VTE were included. In the combined management studies, the overall rate of thromboembolic events was nine out of 2056 patients (0.44%, 95% CI 0.2%-0.83%) in whom anticoagulants were withheld based oil the D-dimer result and a low clinical score. Similar results were obtained with qualitative and quantitative D-dimer tests and with different decision rules. The rate of exclusion varied between 30% and 50% and was highest with a low incidence of VTE among those referred. Conclusion: Withholding anticoagulant treatment in patients suspected of VTE oil the basis of a work-Up consisting Of a low clinical probability combined with either a qualitative or quantitative D-dimer test result is safe.