Among patients who develop venous thromboembolism (VTE), use of the D-dimer assay may not help to determine whether patients require extended treatment, according to research published in Blood Advances.

Previous research has indicated that recurrence of VTE is likely among patients with permanent prothrombotic conditions, or where the VTE is unprovoked by an environmental factor. Although anticoagulation treatment is standard for up to 6 months in all patients, some patients, particularly those with an unprovoked VTE, receive indefinite treatment.

For the prospective Apidulcis study, researchers evaluated the clinical utility of an algorithm that incorporated D-dimer and low-dose apixaban among patients with a first episode of VTE.

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Overall, 778 patients were enrolled to this study. Among these, at baseline, 63.1% were male sex, the median age was 59 years, 75.6% of patients had an unprovoked DVT, and 25.1% of patients had received a prior anticoagulant treatment for more than 18 months. The study protocol indicated that where baseline D-dimer during anticoagulation was negative, treatment was discontinued; thereafter, testing was repeated at 15, 30, and 60 days.

After an initial positive test result, 60.9% of the overall cohort received apixaban for 18 months, which comprised the follow-up period. The study was, however, interrupted early because of a high rate of events among patients not on treatment (7.3% vs 1.1%, respectively; adjusted hazard ratio, 8.2; 95% CI, 3.2-25.3). These events included symptomatic proximal deep vein thrombosis/pulmonary embolism recurrence, death from VTE, and major bleeding.

“In a setting of patients with VTE characterized by a high risk of recurrences, the results of this study show that a serial D-dimer procedure, in isolation, fails to identify those in whom anti-coagulation can be safely discontinued, whereas reduced-dose apixaban confers protection that is effective and reassuringly safe,” the authors wrote in their report.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, or device companies. Please see the original reference for a full list of authors’ disclosures. 


Palareti G, Poli D, Ageno W, et al. D-dimer and reduced-dose apixaban for extended treatment after unprovoked venous thromboembolism: the Apidulcis study. Blood Adv. 2022;6(23):6005-15. doi:10.1182/bloodadvances.2022007973