Working…
ClinicalTrials.gov
ClinicalTrials.gov Menu

Transcranial Doppler (TCD) Assessment During Early Anti-thrombotic Therapy After Bioprosthetic Aortic Valve Replacement (Tissue-Valve)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
 
ClinicalTrials.gov Identifier: NCT00465218
Recruitment Status : Completed
First Posted : April 24, 2007
Last Update Posted : June 21, 2012
Sponsor:
Collaborator:
Edwards Lifesciences
Information provided by (Responsible Party):
Marc Ruel MD MPH FRCSC, Ottawa Heart Institute Research Corporation

Tracking Information
First Submitted Date April 20, 2007
First Posted Date April 24, 2007
Last Update Posted Date June 21, 2012
Study Start Date March 2007
Actual Primary Completion Date December 2007   (Final data collection date for primary outcome measure)
Current Primary Outcome Measures
 (submitted: October 31, 2007)
Differences in the rate of doppler-detected cerebral micro emboli between the two prophylactic treatments of thrombosis [ Time Frame: 1 month after surgery ]
Original Primary Outcome Measures Not Provided
Change History Complete list of historical versions of study NCT00465218 on ClinicalTrials.gov Archive Site
Current Secondary Outcome Measures
 (submitted: October 31, 2007)
Differences in the degree of inhibition of platelet aggregation between the two prophylactic treatments of thrombosis [ Time Frame: 1 month after surgery ]
Original Secondary Outcome Measures Not Provided
Current Other Pre-specified Outcome Measures Not Provided
Original Other Pre-specified Outcome Measures Not Provided
 
Descriptive Information
Brief Title Transcranial Doppler (TCD) Assessment During Early Anti-thrombotic Therapy After Bioprosthetic Aortic Valve Replacement
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"
Brief Summary 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].
Detailed Description

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:

  1. Primary outcome:

    Bilateral counts of cerebral emboli in the middle cerebral arteries with transcranial doppler ultrasound at one month after surgery

  2. Secondary outcomes:

Platelet function, incidence of major adverse neurologic and bleeding events at one month following surgery

Study Type Observational
Study Design Observational Model: Case Control
Time Perspective: Prospective
Target Follow-Up Duration Not Provided
Biospecimen Not Provided
Sampling Method Non-Probability Sample
Study Population Patients with aortic valve stenosis and/or insuficiency undergoing aortic valve replacement with a bioprosthetic valve (tissue valve).
Condition Aortic Valve Disease
Intervention 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
Study Groups/Cohorts
  • 1
    High dose aspirin (325 mg)
    Intervention: Procedure: Prophylaxis of Thrombosis after aortic valve replacement
  • 2
    Low dose aspirin (81 mgs) plus warfarin
    Intervention: Procedure: Prophylaxis of Thrombosis after aortic valve replacement
Publications *

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Recruitment Information
Recruitment Status Completed
Actual Enrollment
 (submitted: June 20, 2012)
56
Original Enrollment
 (submitted: April 20, 2007)
60
Actual Study Completion Date March 2011
Actual Primary Completion Date December 2007   (Final data collection date for primary outcome measure)
Eligibility Criteria

Inclusion Criteria:

  • Patients undergoing primary aortic valve replacement with bioprosthetic (tissue) valve.

Exclusion Criteria:

  • Emergency surgery or redo operations.
  • Patients with history of transient ischemic attacks, stroke, or history of carotid stenosis greater than 50% as detected by carotid duplex doppler or angiography.
  • Patients with COPD who are CO2 retainers.
  • Patients with LV function less than 50%, or enlarged left ventricle greater than 50 mm as detected by echocardiography or previous history of thromboembolism.
  • Patients with history of atrial fibrillation or heart rhythm disturbances.
Sex/Gender
Sexes Eligible for Study: All
Ages 18 Years and older   (Adult, Older Adult)
Accepts Healthy Volunteers No
Contacts Contact information is only displayed when the study is recruiting subjects
Listed Location Countries Canada
Removed Location Countries  
 
Administrative Information
NCT Number NCT00465218
Other Study ID Numbers 2006785-01H
Has Data Monitoring Committee No
U.S. FDA-regulated Product Not Provided
IPD Sharing Statement Not Provided
Responsible Party Marc Ruel MD MPH FRCSC, Ottawa Heart Institute Research Corporation
Study Sponsor Ottawa Heart Institute Research Corporation
Collaborators Edwards Lifesciences
Investigators
Principal Investigator: Marc Ruel, MD, MPH Ottawa Heart Institute Research Corporation
Study Director: Thierry Mesana, MD, PhD Ottawa Heart Institute Research Corporation
PRS Account Ottawa Heart Institute Research Corporation
Verification Date June 2012