D-dimer testing as an adjunct to ultrasonography in patients with clinically suspected deep vein thrombosis: prospective cohort study

Abstract

Objective To investigate the efficacy of using a rapid plasma d-dimer test as an adjunct to compression ultrasound for diagnosing clinically suspected deep vein thrombosis. Design d-dimer concentrations were determined in all patients with a normal ultrasonogram at presentation. Repeat ultrasonography was performed 1 week later only in patients with abnormal d-dimer test results. Main outcome measure Patients with normal ultrasonograms were not treated with anticoagulants and were followed for 3 months for thromboembolic complications. Setting University research and affiliated centres. Subjects 946 patients with clinically suspected deep vein thrombosis. Results Ultrasonograms were abnormal at presentation in 260 (27.5%) patients. Of the remaining 686 patients tested for d-dimer, 88 (12.8%) had abnormal concentrations. During follow up venous thromboembolic complications occurred in one of the 598 patients who were not treated with anticoagulants and who had an initial normal ultrasonogram and d-dimer concentration, whereas thromboembolic complications occurred in two of the 83 untreated patients who had abnormal d-dimer concentrations but a normal repeat ultrasonogram. The cumulative incidence of venous thromboembolic complications during follow up was 0.4% (95% confidence interval 0% to 0.9%). The rapid plasma d-dimer test used as an adjunct to compression ultrasonography resulted in a reduction in the mean number of repeat ultrasound examinations and additional hospital visits from 0.7 to 0.1 per patient. Conclusions Testing for d-dimer as an adjunct to a normal baseline ultrasound examination decreased the number of subsequent ultrasound examinations considerably without any increased risk of venous thromboembolic complications in patients not receiving anticoagulants. The use of ultrasound and testing for d-dimer enabled treatment decisions to be made at the time of presentation in most patients.

D-Dimer Testing for Deep Venous Thrombosis: A Metaanalysis

“…Other management trials suggest that repeated ultrasound examinations may be safely avoided in patients with an initially negative ultrasound and a negative D-dimer test result (92,93 ). Interestingly, these studies have used various D-dimer assays from several different method categories, including second-generation latex agglutination assays (87,91 ), membrane ELISA assays (94 ), and the erythrocyte agglutination assay (55,90,92,93 ). To firmly establish the safety of these and other approaches, large trials are needed that have adequate numbers of patients at the ends of the branching pathways (95 ).…”

Risk of Venous Thromboembolism after a Single Normal Proximal Lower Extremity Venous Ultrasound

“…Their 3-month rate of VTE was 0.4% (CI = 0.0%-0.9%), and they reduced the volume of repeated US scans by 87%. 3 Similarly, Wells et al 14 reported that patients with low pretest probability and initially normal proximal US results (55% of patients) could forgo the repeated US at 1 week, because their 3-month rate of VTE was 0.6% (CI = 0.1%-1.8%).…”

“…This protocol will be referred to as serial proximal US. 2,3 The second protocol is one-time whole-leg, extended US (single complete US), evaluating both the proximal and distal calf infrapopliteal veins. 4,5 Serial proximal US requires repeated scanning in one week in a large number of patients with initially normal US results, most of whom will not have evidence of DVT on their repeated US.…”

Recanalization after acute deep vein thrombosis

“…Therefore, when faced with a clinical suspicion of DVT and a need to assess the status of a thrombosed vein in order to treat its complications, specific examinations or supplementary diagnostic methods capable of directly or indirectly demonstrating the presence and extent of the thrombus must be used. Clinical prediction models such as those proposed by Wells et al 17 , in combination with laboratory D-dimer testing and imaging exams with color duplex mapping (CDM), have made it easier to reliably diagnose DVT 18,19 .…”