Preventing blood clots after hip and knee surgeries

Extended Venous Thromboembolism Prophylaxis Comparing Rivaroxaban and Aspirin to Aspirin Alone Following Total Hip and Knee Arthroplasty (EPCATIII)

PHASE3 · Nova Scotia Health Authority · NCT04075240

This study is testing if taking aspirin alone is just as good as taking aspirin with another medication to prevent blood clots in people having hip or knee surgery.

Quick facts

PhasePHASE3
Study typeInterventional
Enrollment5400 (estimated)
Ages18 Years and up
SexAll
SponsorNova Scotia Health Authority (other)
Locations1 site (Halifax, Nova Scotia)
Trial IDNCT04075240 on ClinicalTrials.gov

What this trial studies

This clinical trial involves patients undergoing elective total hip and knee arthroplasty who will be randomized to receive either aspirin alone or a combination of aspirin and rivaroxaban to prevent venous thromboembolism (VTE). The study aims to determine if aspirin alone is as effective as the combination therapy in preventing VTE. Aspirin is a cost-effective option, and previous studies have indicated that the combination therapy is safe and effective. The trial will assess the non-inferiority of aspirin compared to the combination treatment.

Who should consider this trial

Good fit: Ideal candidates are patients scheduled for elective total hip or knee arthroplasty who can provide informed consent.

Not a fit: Patients with a history of venous thromboembolism, major bleeding, or certain medical conditions may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide a more affordable and effective option for preventing blood clots in patients undergoing hip and knee surgeries.

How similar studies have performed: Previous studies have shown success with similar approaches, particularly the efficacy of aspirin and rivaroxaban in preventing VTE.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. Patients undergoing elective THA/TKA at the participating institutions will be potentially eligible for this study
2. Written informed consent in accordance with federal, local and institutional guidelines

Exclusion Criteria:

1. Previous documented VTE (proximal DVT or any PE)
2. Hip or lower limb fracture in the previous three months, not related to present surgery
3. Metastatic cancer
4. Life expectancy less than 6 months
5. History of major bleeding that in the judgment of the investigator precludes use of anticoagulant prophylaxis
6. History of aspirin allergy, active peptic ulcer disease or gastritis that in the judgment of investigator precludes use of aspirin
7. History of significant hepatic disease or any other condition that in the judgment of the investigator precludes the use of rivaroxaban
8. Creatinine clearance less than 15 ml per minute
9. Pre-operative platelet count less than 100 x 109 /L
10. Need for long-term anticoagulation due to a pre-existing co-morbid condition or due to the development of VTE following surgery but prior to randomization
11. Received anticoagulation post operatively
12. Bilateral THA/TKA or simultaneous hip and knee arthroplasty
13. Major surgical procedure within the previous 3 months
14. Requirement for major surgery post arthroplasty within a 90 day period
15. Chronic daily aspirin use with dose greater than 100 mg a day
16. Women of childbearing potential who are not abstinent or do not use effective contraception or are breast-feeding throughout the study drug period
17. Unwilling or unable to give consent
18. Previous participation in the EPCAT III study
19. Under 18 years of age
20. Concomitant use of drugs that are strong inhibitors of P-gp AND CYP3A4 (e.g., systemic treatment with ketoconazole, itraconazole, or ritonavir) or strong inducers of P-gp AND CYP3A4 (e.g., rifampicin, phenytoin, carbamazepine, phenobarbital, St. John's Wort)
21. Known allergy to food dye

Where this trial is running

Halifax, Nova Scotia

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Venous Thromboembolism, total hip and knee arthroplasty

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.