Home
Search
Study Topics
Glossary
|
|
|
|
|
|
Sponsors and Collaborators: |
University of Ottawa Heart Institute Edwards Lifesciences |
---|---|
Information provided by: | University of Ottawa Heart Institute |
ClinicalTrials.gov Identifier: | NCT00465218 |
The purpose of this study is to determine if there is any difference in the counts of cerebral emboli and platelet function between two prophylactic treatments of thrombosis currently used at University of Ottawa Heart Institute for the first three months after surgery in low-risk patients undergoing aortic valve replacement with a bioprosthetic valve: 1) daily use of high-dose aspirin [325 mgs], and 2) the combination of oral Warfarin [target INR 2.0 to 3.0] and low-dose aspirin [81 mg].
Condition | Intervention | Phase |
---|---|---|
Aortic Valve Disease |
Procedure: Prophylaxis of Thrombosis after aortic valve replacement |
Phase I |
Study Type: | Observational |
Study Design: | Case Control, Prospective |
Official Title: | "Transcranial Doppler Assessment of Cerebral Embolization During Early Anti-Thrombotic Therapy After Bioprosthetic Aortic Valve Replacement: Comparison of High-Dose Aspirin Versus Warfarin Plus Low-Dose Aspirin" |
Estimated Enrollment: | 60 |
Study Start Date: | March 2007 |
Estimated Study Completion Date: | December 2008 |
Groups/Cohorts | Assigned Interventions |
---|---|
1
High dose aspirin (325 mg)
|
Procedure: Prophylaxis of Thrombosis after aortic valve replacement
Two standard prophylactic treatments of thrombosis within the first 3 months postsurgery currently used in our institution: a) daily dose of aspirin (325 mgs; b) daily dose of aspirin (81 mg) plus Warfarin for target INR 2.0-2.5
|
2
Low dose aspirin (81 mgs) plus warfarin
|
Procedure: Prophylaxis of Thrombosis after aortic valve replacement
Two standard prophylactic treatments of thrombosis within the first 3 months postsurgery currently used in our institution: a) daily dose of aspirin (325 mgs; b) daily dose of aspirin (81 mg) plus Warfarin for target INR 2.0-2.5
|
Background:
There are several medications used to prevent blood clotting in patients undergoing surgical replacement of their aortic valves with tissue valves. One of these medications is called warfarin (Coumadin ®) which prevents blood clotting by making the blood "thinner." Another medication is aspirin which prevents the aggregation (clustering) of cells in the blood called platelets. Some clinicians consider that using only aspirin should be enough to protect the patients against the presence of clots in the blood, but others consider that aspirin should be combined with warfarin for better protection. Moreover, physicians express concern over the use of oral anticoagulation due to the possibility of an increased risk of bleeding. The effects of these medications for preventing blood clots traveling to the brain after the surgery are currently unknown. Transcranial doppler ultrasound will be used in these patients to evaluate non-invasively the quantity of fragments of clots circulating in the arteries of the brain. In addition, platelet function will be measured to determine how effective these treatments are for preventing the aggregation of the blood cells called platelets, which may be involved in clot formation.
Objective:
Our purpose is to determine if there is any difference in the counts of cerebral emboli and platelet function between two prophylactic treatments of thrombosis currently used in our institution for the first three months after surgery in these patients: 1) daily use of high-dose aspirin [325 mgs], and 2) the combination of oral Warfarin [target INR 2.0 to 3.0] and low-dose aspirin [81 mg].
Methods:
Patients with low risk profile undergoing primary aortic valve replacement with a bioprosthetic (tissue) valve will be eligible for the study. Patients will receive one of the two prophylactic treatments of thrombosis (1 or 2) depending on the surgeon's preference. Platelet function will be measured before surgery and transcranial doppler within the first 24 hours immediately after the surgery. At the end of one month following surgery, all patients will undergo transcranial doppler and platelet function assessment. The study will be powered on demonstrating the hypothesis of substantial equivalence between the two treatments as regarding the primary outcome (cerebral emboli).
Outcome measures:
Primary outcome:
Bilateral counts of cerebral emboli in the middle cerebral arteries with transcranial doppler ultrasound at one month after surgery
Platelet function, incidence of major adverse neurologic and bleeding events at one month following surgery
Ages Eligible for Study: | 18 Years and older |
Genders Eligible for Study: | Both |
Accepts Healthy Volunteers: | No |
Sampling Method: | Non-Probability Sample |
Patients with aortic valve stenosis and/or insuficiency undergoing aortic valve replacement with a bioprosthetic valve (tissue valve).
Inclusion Criteria:
Exclusion Criteria:
Contact: Rosendo A. Rodriguez, MD, PhD | 613-761-4263 | Rrodriguez@ottawaheart.ca |
Contact: Marc Ruel, MD, MPH | 613-761-4893 | MRuel@ottawaheart.ca |
Canada, Ontario | |
University of Ottawa Heart Institute | Recruiting |
Ottawa, Ontario, Canada, K1Y 4W7 |
Principal Investigator: | Marc Ruel, MD, MPH | University of Ottawa Heart Institute |
Study Director: | Rosendo A. Rodriguez, MD, PhD | University of Ottawa Heart Institute |
Study Director: | Melanie Forgie, MD, MSc | The Ottawa Hospital |
Study Director: | Thierry Mesana, MD, PhD | University of Ottawa Heart Institute |
Study ID Numbers: | 2006785-01H |
Study First Received: | April 20, 2007 |
Last Updated: | September 17, 2008 |
ClinicalTrials.gov Identifier: | NCT00465218 |
Health Authority: | Canada: Ethics Review Committee |
Bioprosthesis Thrombosis Cerebral emboli Transcranial Doppler Platelet function tests |
Aspirin Embolism Warfarin Thrombosis |