D-DIMER TESTING AS AN ADJUNCT TO ULTRASONOGRAPHY IN PATIENTS WITH CLINICALLY SUSPECTED DEEP-VEIN THROMBOSIS - PROSPECTIVE COHORT STUDY

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 de termined in all patients with a normal ultrasonogram at presentation. Repeal ultrasonography was performed 1 week later only in patients wit h abnormal D-dimer test results. Main outcome measure Patients with no rmal ultrasonograms were not treated with anticoagulants and were foll owed for 3 months for thromboembolic complications. Setting University research and affiliated centres, Subjects 946 patients with clinicall y suspected deep vein thrombosis. Results Ultrasonograms were abnormal at presentation in 260 (27.5%) patients. Of the remaining 686 patient s tested for D-dimer, 88 (12.8%) had abnormal concentrations. During f ollow up venous thromboembolic complications occurred in one of the 59 8 patients who were not treated with anticoagulants and who had an ini tial normal ultrasonogram and D-dimer concentration, whereas thromboem bolic complications occurred in two of the 83 untreated patients who h ad 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 pl asma D-dimer test used as an adjunct to compression ultrasonography re sulted in a reduction in the mean number of repeat ultrasound examinat ions and additional hospital visits from 0.7 to 0.1 per patient Conclu sions Testing for D-dimer as an adjunct to a normal baseline ultrasoun d examination decreased the number of subsequent ultrasound examinatio ns considerably without any increased risk of venous thromboembolic co mplications in patients not receiving anticoagulants. The use of ultra sound and testing for D-dimer enabled treatment decisions to be made a t the time of presentation in most patients.