The discovery
Joint replacements are among the most common surgeries worldwide, and preventing blood clots is critical to recovery. A Dalhousie-led study published this month — one of the most robust of its kind to date — found that a straightforward treatment following surgery may be just as effective as a more complex one, challenging common assumptions in post-surgical care. The results could simplify care and reduce costs across health systems.
Key findings
In the New England Journal of Medicine study led by Dalhousie's Dr. Sudeep Shivakumar, researchers tested whether aspirin — a simple, low-cost pill — alone could prevent dangerous blood clots after hip or knee replacement surgery.
- More than 5,400 patients in the large Canadian trial were randomly assigned to receive either aspirin or rivaroxaban initially followed by aspirin, the current standard approach in many settings.
- The results showed remarkably similar outcomes between both approaches. About 0.5% of patients in each group experienced serious blood clots, indicating that aspirin alone performed just as well as the more complex regimen. Bleeding complications were also comparable, with no meaningful differences between groups.
- Over a 90-day follow-up, survival and event-free outcomes were virtually identical, reinforcing the conclusion that aspirin alone is “noninferior,” meaning it is equally effective within clinically accepted limits.
Why it matters
Current approaches to post-surgery care often rely on newer anticoagulants that can be costly and require monitoring, which may limit access in some settings.
The study is the first large, double-blind trial to directly compare these strategies head-to-head, providing high-quality evidence at a time when surgical volumes are rising globally.
The findings could make care delivery more efficient and cost-effective across health systems.
Dr. Sudeep Shivakumar, an associate professor and head of the Division of Hematology in Dal's Faculty of Medicine.
"We now have evidence that an aspirin only strategy for prevention of blood clots after hip and knee replacements is safe and effective, and hopefully this study can better inform patients and health care providers when caring for patients after joint replacements," says Dr. Sudeep Shivakumar, an associate professor and head of the Division of Hematology in Dal's Faculty of Medicine.
Learn more
Paper: "Rivaroxaban Then Aspirin vs. Aspirin Alone after Total Hip or Knee Arthroplasty"
Researchers: Dr. Sudeep Shivakumar