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Aspirin no different than rivaroxaban for prevention of VTE after TKA or THA
Clinical Question
Is aspirin as effective as rivaroxaban for prevention of venous thromboembolism (VTE) after total hip or knee arthroplasty?
Bottom line
Extended prophylaxis with low dose aspirin is similar in efficacy to rivaroxaban for the prevention of symptomatic venous thromboembolism (VTE) following total knee or hip arthroplasty. Aspirin is cheap, widely available, and effective, making it a good alternative to the more costly direct oral anticoagulants. 1b
Reference
Study design: Randomized controlled trial (double-blinded)
Funding: Government
Setting: Inpatient (any location) with outpatient follow-up
Synopsis
In this study, investigators tested the efficacy of aspirin 81 mg compared with rivaroxaban 10 mg for extended VTE prophylaxis following total knee arthroplasty (TKA) or total hip arthroplasty (THA). All patients in the study initially received in-hospital prophylaxis with rivaroxaban 10 mg daily for 5 days following surgery. Patients randomized to the rivaroxaban group (n=1718) continued this treatment while those randomized to the other group (n=1709) started aspirin 81 mg daily. Additionally, patients on pre-operative aspirin 81 mg were allowed to continue its use in the post-operative phase. Study treatment was continued for 9 additional days in TKA patients and 30 additional days in THA patients. The two pills, rivaroxaban or aspirin, were administered in identical gelatin capsules. Patients in the two groups had similar baseline characteristics and were followed up for 90 days. In the intention-to-treat analysis, low dose aspirin was non-inferior to rivaroxaban for the primary efficacy outcome of symptomatic proximal deep vein thrombosis or pulmonary embolism (0.64% vs. 0.70%, p<0.001 for non-inferiority). For the primary safety outcome of major bleeding or clinically relevant non-major bleeding, there was no significant difference detected between the two groups (1.29% in aspirin group vs. 0.99% in rivaroxaban group, p=0.43).
Reviewer
Nita Shrikant Kulkarni, MD
Assistant Professor in Hospital Medicine
Northwestern University
Chicago, IL
Comments
Good info
‘... more costly...’ indeed. Cost online of Bayer Aspirin 81mg @ 100 is $4.19. Cost to me of Xarelto @ 100 for prophylaxis was $363 26 or 86.6 times times more costly
This study needs to be extended for more power to validate the findings by increasing the number of people enrolled into the study.
The orthopods look after the patients after surgery before returning them to my care.
Good poem
Vte prophylaxis
Most vte prophylaxis protocols across Canada are based on the flawed 2008 accp guidelines put out by geertz et al with MAJOR conflicts of interest with the pharm industry, acknowledged in the 2012 guidelines. Accreditation Canada’s “getting started” kit was based on those guidelines, which are clearly wrong. We should all be redoing our protocols based on this poem and the 2012 guidelines to reduce the harm (NNH around 150, NNT in the thousands in the current protocol, and for pe even larger NNT). Worth reading Kotaska et al bjog from feb 2018 for the obstetrical vte story (not a great paper but makes some good points).
Another very expensive drug that was foisted onto doctors while a well known inexpensive drug is just as effective as the newer drug. We wonder why the health care system is in desperate financial crisis. When a very inexpensive well known drug works as well for less than 1% of the cost of the new drug on the market.