Systematic review compares new and old anticoagulation options for acute VTE

The benefits and risks of 8 different anticoagulation strategies for patients with venous thromboembolism (VTE), including heparin and new oral anticoagulants, were compared in a large new analysis.

Researchers used data from 45 trials with 44,989 patients to compare the strategies: vitamin K antagonists combined with unfractionated heparin (UFH), low-molecular-weight heparin (LMWH), or fondaparinux; LMWH alone; LMWH with dabigatran or edoxaban; rivaroxaban; or apixaban. Outcomes were recurrent VTE and major bleeding. Results were published in the Sept. 17 Journal of the American Medical Association.

On the outcome of recurrent VTE, the only strategy that showed substantially different results from the others was UFH with a vitamin K antagonist, which significantly increased risk of VTE recurrence (hazard ratio [HR], 1.42, compared to LMWH-vitamin K antagonist). Looking at bleeding during treatment, only rivaroxaban and apixaban stood out significantly, both reducing the risk of a bleed compared to LMWH-vitamin K antagonist (HR, 0.55 for rivaroxaban and 0.31 for apixaban).

Based on the results, UFH appears to be the least effective strategy for preventing VTE recurrence, the study authors concluded. This supports current guidelines, they noted, although UFH may still be appropriate for certain patients, such as those with severe renal insufficiency or massive pulmonary embolism. The study also indicates that rivaroxaban and apixaban may pose the lowest risk of bleeding, which may be helpful information to clinicians, since current guidelines were published prior to the latest evidence on using new oral anticoagulants for acute VTE, the study authors noted.

They cautioned that their analysis included only use of the treatments for acute VTE, not secondary prevention. In addition, the research was limited by the total absence of head-to-head trials comparing the new oral anticoagulants. Costs of the different regimens were also not addressed. The authors called for direct comparison trials, patient-level meta-analyses, or high-quality nonrandomized studies to confirm their findings.