Abstract Number: PB2261
Meeting: ISTH 2020 Congress
Background: Rivaroxaban and apixaban are increasingly being used to treat venous thromboembolism (VTE). Whilst on these agents, the use of D-dimer in the prediction of recurrent VTE (rVTE) is yet to be established.
Aims: To assess the efficacy of D-dimer in the assessment of suspected symptomatic rVTE (deep vein thrombosis [DVT] or pulmonary embolism [PE]) in patients on rivaroxaban or apixaban for previous VTE.
Methods: Chart review of patients on rivaroxaban or apixaban for previous VTE presenting with suspected rVTE from March 2016 to January 2020 at Monash Health, Melbourne. Only patients who had an anti-Xa drug level (IL Test on the ACL TOP analyser), concurrent D-dimer (IL Test D-dimer HS on the ACL TOP analyser) and objective imaging were included. Two haematologists and a radiologist reviewed indeterminate rVTE cases. The primary outcome was accuracy of D-dimer in predicting rVTE utilising our standard D-dimer threshold, 0.23mg/l.
Results: Of 57 potentially eligible patients, 5 were excluded due to inability to confirm rVTE based on available clinical and radiological evidence (See Table 1 for included patient characteristics). Suspected rVTE occurred 5.1 months post index VTE (median, range 0.03-121) with anti-Xa levels and D-dimer shown in Figure 1. Subtherapeutic anti-Xa levels (< 30ng/ml) were detected in 17%. Suspected rVTE comprised DVT, PE or both in 31%, 65% and 4% respectively. rVTE was subsequently confirmed in 21% of which 73% were PE. D-dimer sensitivity was 64% (95%CI 31-89) and specificity was 73% (95%CI 57-86%), with 55% of false positives from suspected rVTE within one month of index VTE.
Conclusions: In patients with suspected rVTE who are taking rivaroxaban or apixaban with detectable drug activity, the IL Test D-dimer is not universally suppressed and the routine laboratory threshold of 0.23mg/l may retain its utility.
|Characteristics||N = 52|
|Age (median, range, years)||51 (17-85)|
|Apixaban level at suspected rVTE (median, range, ng/ml)||100 (14-403)|
|Rivaroxaban level at suspected rVTE (median, range, ng/ml)||102 (10-538)|
|Time from index VTE (median, range, months)||5.1 (0.03-121)|
|Confirmed rVTE (%)||21|
|Greater than 30-day follow-up period post suspected rVTE (% of not confirmed VTE)||90|
[Table 1. Patient characteristics]
To cite this abstract in AMA style:Yuen HLA, Malan E, Clifford J, Bennett A, So A, Leung P, Chunilal S. D-Dimer is Useful in the Assessment of Suspected Recurrent Venous Thromboembolism in Patients on Rivaroxaban or Apixaban [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/d-dimer-is-useful-in-the-assessment-of-suspected-recurrent-venous-thromboembolism-in-patients-on-rivaroxaban-or-apixaban/. Accessed January 23, 2022.
« Back to ISTH 2020 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/d-dimer-is-useful-in-the-assessment-of-suspected-recurrent-venous-thromboembolism-in-patients-on-rivaroxaban-or-apixaban/