Performance of D-Dimers in Patients with Prior History of Venous Thromboembolism Based on Anticoagulation Status

Abstract

Background: D-dimers frequently stay elevated in patients with prior history of venous thromboembolism (VTE). Moreover, D-dimers seem to have lower diagnostic yield in patients presenting with a suspicion of recurrent VTE and it is not clear how D-dimers perform in patients on anticoagulation. Aim: To evaluate the performance of D-dimers in patients with a history of VTE based on anticoagulation status. Methods: The PREDICTORS study is an international prospective multicenter observational cohort study of outpatients with suspected VTE recurrence. The aim is to improve the performance of diagnostic strategies in patients with a suspicion of recurrent VTE. Pre-test clinical probability was assessed, and D-dimers were performed based on local clinical practices. Negative D-dimers were determined based on the manufacturer's threshold for every commercial assay used in each center. Recurrent VTE events (defined as proximal deep venous thrombosis or segmental or more proximal pulmonary embolism) at enrollment and during the 3-month follow-up were assessed and all suspected recurrent events were independently adjudicated. Results: D-dimer measurements were used in the diagnostic management of 482 patients, of which, 168 patients were on anticoagulation and 314 were not on anticoagulation. At enrollment, the prevalence of recurrent VTE was 29.9% (144/482). Moreover, at the index suspicion, 35.1% (169/482) had negative D-dimers. Amongst patients on anticoagulation, 4/90 (4.4%; 95%CI 1.2%-11.0%) and 21/78 (26.9%) had recurrent VTE at enrollment in patients with negative and positive D-dimers, respectively. During follow-up, no recurrent VTE occurred in patients with negative D-dimers. Amongst patients without anticoagulation, 2/79 (2.5%; 95%CI 0.3%-8.9%) and 117/235 (49.8%) had recurrent VTE at enrollment in patients with negative and positive D-dimers, respectively. One recurrent VTE occurred during follow-up amongst patients with initial negative D-dimers (1.3%; 95%CI 0.0-7.0%). Conclusion: In patients presenting with a suspected recurrent VTE, the prevalence of VTE was high, including in patients receiving anticoagulant therapy. Prevalence of VTE based on D-dimers positivity was comparable between patients on anticoagulation and patients without anticoagulation. False negative rate of D-dimers appears to be higher in patients with a suspicion of recurrent VTE than in patients with a suspected first thromboembolic event. Further studies are needed to assess if a change in the D-dimers cut-off could improve diagnostic yield.