Negative D-dimer result to exclude recurrent deep venous thrombosis: A management trial

Background: All of the available diagnostic tests for deep venous thrombosis (DVT) have limitations for excluding acute recurrent DVT. Measurement of plasma D-dimer by using an automated quantitative assay may be useful as a rapid exclusion test in patients with suspected recurrent DVT. Objective: To test the safety of withholding additional diagnostic testing and heparin treatment in patients who have a negative D-dimer result at presentation (using the automated quantitative assay STA-Liatest D-di), regardless of their symptoms. Design: Prospective cohort study. Setting: Academic medical center in the United States. Patients: 300 consecutive patients with suspected recurrent DVT. Intervention: Patients underwent D-dimer testing at presentation. In patients with negative D-dimer results, heparin therapy was withheld, and no further diagnostic testing for DVT was done as part of the initial evaluation. Patients with positive D-dimer results underwent compression ultrasonography. Measurements: The primary outcome measure was a diagnosis of new symptomatic venous thromboembolism confirmed by diagnostic testing during the 3-month follow-up period. Results: Of the 300 study patients, the D-dimer result was negative at presentation in 134 patients (45%; negative cohort) and positive at presentation in 166 patients. Of the 166 patients, compression ultrasonography documented new DVT in 54 patients. Compression ultrasonography findings were normal in 79 patients and were inconclusive in 33 patients. After 3 months of follow-up, 1 of 134 patients in the negative cohort had confirmed venous thromboembolism (0.75% [95% Cl, 0.02% to 4.09%]). Venous thromboembolism on follow-up could not be definitively excluded in 5 patients with recurrent leg symptoms and in 1 patient who died. If these patients are considered to have venous thromboembolism, the incidence during the 3-month follow-up period would be 6.0% (Cl, 2.6% to 11.4%) (8 of 134 patients). Limitations: There is no accepted diagnostic reference standard for recurrent DVT. The precision of the estimate of the incidence of venous thromboembolism on follow-up and the generalizability to settings other than an academic health center should be evaluated. Conclusions: Measurement of plasma D-dimer by using the automated quantitative assay STA-Liatest D-di seems to provide a simple method for excluding acute recurrent DVT in symptomatic patients.