CLOT+

Doctor, I am having hip or knee replacement surgery. Can I take an aspirin to protect myself from blood clots after surgery?

We don't know yet whether aspirin after hip or knee replacement will provide enough protection from DVT and PE. This study found that taking an aspirin daily after taking Xarelto® for the first 5 days was as safe as continuing Xarelto® for a longer period of time.

Study highlights

There was no difference in the number of DVT, PE, or major bleeding events between people taking Xarelto® for 5 days followed by aspirin and people taking a Xarelto® for a longer period of time.

This study was not designed to answer the question of whether it is safe to take aspirin starting from the first day after surgery. However, these results encouraged researchers to start a new study that will provide the data needed to answer that question.

Understanding the problem

Hip and knee replacement surgery increases the risk of forming DVT and PE. Taking a low dose of an anticoagulant like Xarelto® for 10 to 30 days after surgery reduces this risk to about 1 to 3%.

However, blood clotting is needed at the surgery site to stop bleeding. Excessive bleeding around an artificial joint can cause complications that require longer hospital stays and a poor functional outcome from the surgery.

Aspirin may not increase the risk of bleeding as much as anticoagulants. However, aspirin may also not be as good at protecting patients from DVT and PE.

The researchers for this study wanted to know if taking a short course of Xarelto® followed by aspirin would be as safe and effective as continuing Xarelto® after elective hip or knee replacement surgery.


Who? The study included 1804 people who had elective hip replacement surgery and 1620 people who had elective knee replacement surgery. People who had fractures and metastatic cancer were excluded. About 2% of study participants had a past history of DVT or PE.

What? The study compared a longer course of Xarelto® with a short course of Xarelto® followed by aspirin. People did not know which of the two treatments they were taking after the first 5 days. If they were taking low-dose aspirin prior to surgery, for other reasons, they continued aspirin in addition to the study drug after surgery.

Xarelto®

vs

Aspirin

Xarelto®, 10 mg once a day

for 14 days after knee replacement surgery

or 35 days after hip replacement surgery



Xarelto®, 10 mg once a day for 5 days,

followed by aspirin, 81 mg once a day

for 9 days after knee replacement surgery

or 30 days after hip replacement surgery


Longer course of Xarelto® vs short course of Xarelto® followed by aspirin in people who have elective hip or knee replacement surgery

Outcomes at 90 days after surgery

Rate of events with Xarelto®

Rate of events with Xarelto® followed by aspirin

Results

Symptomatic DVT or PE

7 out of 1000 people

6 out of 1000 people

No difference in the number of DVT or PE between the two study groups*

Major bleeding

3 out of 1000 people

5 out of 1000 people

No difference in the number of major bleeds between the two study groups*

*Although the rates for the 2 groups look different, the differences were not statistically significant—this means that the difference could simply be due to chance rather than due to the different treatments.

This Evidence Summary is based on the following article:

Anderson DR, Dunbar M, Murnaghan J, et al. Aspirin or Rivaroxaban for VTE Prophylaxis after Hip or Knee Arthroplasty. N Engl J Med. 2018 Feb 22;378(8):699-707. doi: 10.1056/NEJMoa1712746. PubMed

Published: Thursday, August 26, 2021