Aspirin was not significantly different from rivaroxaban for the prevention of proximal deep vein thrombosis or pulmonary embolism after total hip or knee arthroplasty following a 5-day postoperative treatment with rivaroxaban, according to data published in the New England Journal of Medicine.

Researchers conducted the EPCAT II trial (ClinicalTrials.gov identifier, NCT01720108) to study the effectiveness and safety of extended prophylaxis with aspirin compared with rivaroxaban for the prevention of venous thromboembolism after total hip or total knee arthroplasty. A total of 3424 participants undergoing hip arthroplasty (n=1804) or knee arthroplasty (n=1620) received once-daily oral rivaroxaban 10 mg for 5 days after surgery and were randomly assigned to continue rivaroxaban or switch to aspirin 81 mg daily for an additional 9 days after knee arthroplasty or for 30 days after hip arthroplasty.

Venous thromboembolism occurred in 0.64% of participants who received aspirin and in 0.70% of participants who received rivaroxaban (0.06 percentage point difference; 95% CI, –0.55 to 0.66;


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P <.001 for noninferiority and P =.84 for superiority). In addition, major bleeding complications occurred in 0.47% of participants receiving aspirin and 0.29% of participants receiving rivaroxaban (0.18 percentage point difference; 95% CI, –0.65 to 0.29; P =.42).

The results also showed that clinically important bleeding occurred in 1.29% of participants receiving aspirin and in 0.99% of participants receiving rivaroxaban (0.30 percentage point difference; 95% CI, –1.07 to 0.47; P =.43).

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The investigators noted that the trial population did not consist of an entire inception cohort treated in accordance with a standardized protocol, which prevented the researchers from calculating the absolute event rates of thromboembolic or bleeding complications.

“We found that the inexpensive, widely available generic agent aspirin was not significantly different from the more expensive, direct-oral anticoagulant rivaroxaban for the prevention of symptomatic, clinically important venous thromboembolism after total hip or knee arthroplasty among patients who had received an initial 5-day postoperative course of rivaroxaban,” the authors concluded.

Reference

Anderson DR, Dunbar M, Murnaghan J, et al. Aspirin or rivaroxaban for VTE prophylaxis after hip or knee arthroplasty.  N Eng J Med. 2018;378(8):699-707.