Extended Venous Thromboembolism Prophylaxis Comparing Rivaroxaban to Aspirin Following Total Hip and Knee Arthroplasty

Study Overview
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Brief Summary
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In this study the investigators want to look at whether using aspirin instead of rivaroxaban (after initial treatment with rivaroxaban) works as well at preventing blood clots while also reducing risk of bleeding and is more cost effective in patients who have either a total hip replacement or total knee replacement.

Official Title
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Extended Venous Thromboembolism Prophylaxis Comparing Rivaroxaban to Aspirin Following Total Hip and Knee Arthroplasty

Conditions
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Venous Thromboembolism

Intervention / Treatment
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* Drug: rivaroxaban and ASA


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 1. All patients undergoing elective total hip or knee arthroplasty at the participating institutions will be potentially eligible for this study Exclusion Criteria: Hip or lower limb fracture in the previous three months Metastatic cancer Life expectancy less than 6 months History of major bleeding that in the judgment of the investigator precludes use of anticoagulant prophylaxis History of aspirin allergy, active peptic ulcer disease or gastritis that in judgment of investigator precludes use of aspirin History of significant hepatic disease or any other condition that in the judgement of the investigator precludes the use of rivaroxaban Creatinine clearance less than 30 ml per minute Platelet count less than 100 x 109 /L Need for long-term anticoagulation due to a preexisting co-morbid condition or due to the development of venous thromboembolism following surgery but prior to randomization Did not or will not receive rivaroxaban post-operatively for VTE prophylaxis Bilateral total hip arthroplasty or simultaneous hip and knee arthroplasty Major surgical procedure within the previous three months Requirement for major surgery post arthroplasty within 90 day period Chronic daily aspirin use with dose greater than 100 mg a day Women of child bearing potential who are not abstinent or do not use appropriate contraception throughout the study drug period Geographical inaccessibility for follow-up Unwilling or unable to give consent Previous participation in the study Concomitant use with drugs that are strong inhibitors or inducers of both P-gp and CYP3A4

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: rivaroxaban<br>rivaroxaban 10mg x 9 days for total knee arthroplasty patients; x 30 days for total hip athroplasty patients | Drug: rivaroxaban and ASA<br> <br> |
| Experimental: ASA<br>ASA 81mg x 9 days for total knee arthroplasty patients; x 30 days for total hip athroplasty patients | Drug: rivaroxaban and ASA<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| symptomatic venous thromboembolism |  | up to 4 years | 
| major or clinically relevant non-major bleeding |  | up to 4 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| survival |  | up to 4 years | 
| myocardial infarction |  | up to 4 years | 
| stroke |  | up to 4 years | 
| wound infection |  | up to 4 years | 
| cost-effectiveness |  | up to 4 years |