Novel Oral Anticoagulants for Acute Venous Thromboembolism

Vitamin K antagonists (VKAs), such as warfarin, have been the standard treatment for acute venous thromboembolism (VTE) for several decades. However, several novel oral anticoagulants (NOACs), including rivaroxaban, dabigatran, apixaban, and edoxaban, now pose a challenge to the established regimens.

To evaluate the effectiveness and safety of NOACs versus VKAs, investigators in the Netherlands conducted a systematic review and meta-analysis of studies comparing these two classes of anticoagulants. They analyzed two trials of rivaroxaban, and one trial each of dabigatran, apixaban, and edoxaban, comprising 24,455 patients with acute VTE.

Recurrent VTE occurred in similar numbers of patients receiving NOACs versus VKAs (2.0% and 2.2%, respectively), and the combined relative risk (RR) showed no significant difference (0.88; 95% confidence interval, 0.74–1.05). Fatal pulmonary emboli occurred in nine patients (0.07%) in each group, and the RR for all-cause mortality was 0.97 (95% CI, 0.83–1.14).

Major bleeding occurred less often with NOACs than with VKAs (1.1% vs. 1.7%; RR, 0.6; 95% CI, 0.41–0.88), as did nonfatal intracranial bleeding (0.09% vs. 0.25%; RR, 0.39; 95% CI, 0.16–0.94) and fatal bleeding (0.06% vs. 0.17%; RR, 0.36; 0.15–0.87), although dabigatran was associated with more gastrointestinal bleeding (0.71% vs. 0.39%). There were no significant differences in outcomes when dabigatran, apixaban, and edoxaban were compared with rivaroxaban.