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The purpose of the study is to assess whether the use of warfarin, a commonly used anticoagulation drug, is associated with increased amounts of coronary artery calcification. Studies in animals and preliminary but small retrospective studies in humans have suggested a possible link to increased tissue calcification with use of this drug. The researchers will investigate this by assessing the amount of calcification seen in the coronary arteries using a specialized computed tomography (CT) scan (electron-beam CT) and assessing to see if the amount is influenced by the amount of time a patient has been taking warfarin. The researchers will exclude patients with known coronary artery disease, chronic kidney disease or hyperparathyroidism.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| 1 | Warfarin use < 6 months | ||
| 2 | Warfarin use 6-24 months | ||
| 3 | Warfarin use >24 months |
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| Measure | Description | Time Frame |
|---|---|---|
| Coronary Calcification (Presence and Degree as Measured by Agatston Score) Attributed to Duration of Warfarin Use in Months After Controlling for Standard Cardiovascular Risk Factors to Include the Framingham Risk Score | The Agatston score is calculated using a non-contrast computed tomography (CT) scan to measure for the presence and severity of coronary artery disease through identification of calcification in the coronary arteries. Scores can range from 0 to several thousands. The measure is without units. Score categories are as follows: 0 = no coronary disease; 1-100 = low amount of coronary artery disease; 101-400 = moderately elevated score / moderate coronary artery disease; 401-1000 = severely elevated score; >1000 very severely elevated score. Higher Agatston scores corelate with more coronary artery disease and predict a higher risk of coronary heart disease events and mortality. | EBCT scan is done at time of enrollment of patient into 1 of 3 groups based on warfarin use duration: <6 months; 6-24 months; >24 mos. |
| Measure | Description | Time Frame |
|---|---|---|
| International Normalized Ratio | The International Normalized Ratio (INR) is a standardized lab value that measures the intensity of anticogulation using warfarin. It is used to monitor patients taking warfarin. | EBCT scan is done at time of enrollment of patient into 1 of 3 groups based on warfarin use duration: <6 months; 6-24 months; >24 mos. |
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Inclusion Criteria:
Exclusion Criteria:
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Patients without known coronary heart disease, disorders of calcium metabolism or chronic kidney disease aged > 18 years who are referred to take or currently taking warfarin and are followed in the Anticoagulation Management Clinic at Walter Reed Army Medical Center (WRAMC).
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| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Walter Reed Army Medical Center | Washington D.C. | District of Columbia | 20307 | United States |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 19847375 | Result | Villines TC, O'Malley PG, Feuerstein IM, Thomas S, Taylor AJ. Does prolonged warfarin exposure potentiate coronary calcification in humans? Results of the warfarin and coronary calcification study. Calcif Tissue Int. 2009 Dec;85(6):494-500. doi: 10.1007/s00223-009-9300-4. Epub 2009 Oct 22. |
| Label | URL |
|---|---|
| Publication abstract | View source |
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Recruitment is complete. All patients were recruited from within the Walter Reed Anticoagulation Clinic, as specified in the protocol.
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| ID | Title | Description |
|---|---|---|
| FG000 | Warfarin Use Short Duration | Warfarin use for less than 6 months |
| FG001 | 2 - Warfarin Use Intermediate | Warfarin use for 6 to 24 months in duration |
| FG002 | 3 - Warfarin Use Chronic | Warfarin use >24 months |
| Title | Milestones | Reasons Not Completed | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Overall Study |
|
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| ID | Title | Description |
|---|---|---|
| BG000 | Warfarin Use Short Duration | Warfarin use for less than 6 months |
| BG001 | 2 - Warfarin Use Intermediate | Warfarin use for 6 to 24 months in duration |
| Units | Counts |
|---|---|
| Participants |
|
| Title | Description | Population Description | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Denominator Units Selected | Denominators | Classes |
|---|---|---|---|---|---|---|---|---|---|
| Age, Categorical | Count of Participants |
| Type | Title | Description | Population Description | Reporting Status | Anticipated Posting Date | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Time Frame | Units Analyzed | Denominator Units Selected | Arm/Group Information | Denominators | Classes | Analyses |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Primary | Coronary Calcification (Presence and Degree as Measured by Agatston Score) Attributed to Duration of Warfarin Use in Months After Controlling for Standard Cardiovascular Risk Factors to Include the Framingham Risk Score | The Agatston score is calculated using a non-contrast computed tomography (CT) scan to measure for the presence and severity of coronary artery disease through identification of calcification in the coronary arteries. Scores can range from 0 to several thousands. The measure is without units. Score categories are as follows: 0 = no coronary disease; 1-100 = low amount of coronary artery disease; 101-400 = moderately elevated score / moderate coronary artery disease; 401-1000 = severely elevated score; >1000 very severely elevated score. Higher Agatston scores corelate with more coronary artery disease and predict a higher risk of coronary heart disease events and mortality. | After interim analysis following n=70 showed no effect, further enrollment was halted. | Posted | Jul 2011 | Mean | Standard Deviation | Agatston Score | EBCT scan is done at time of enrollment of patient into 1 of 3 groups based on warfarin use duration: <6 months; 6-24 months; >24 mos. |
1 month (until calcium scan completed).
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| ID | Title | Description | Deaths (Affected) | Deaths (At Risk) | Serious Events (Affected) | Serious Events (At Risk) | Other Events (Affected) | Other Events (At Risk) |
|---|---|---|---|---|---|---|---|---|
| EG000 | Warfarin Use Short Duration | Warfarin use for less than 6 months |
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Cross-sectional nature, small sample size. Initially powered for sample size of 100 subjects, our trial was stopped early after an interim analysis at 70 subjects demonstrated no trend for effect of warfarin after adjusting for standard risk factors.
| Title | Organization | Phone | Extension | |
|---|---|---|---|---|
| Todd C. Villines, MD | Walter Reed Army Medical Center, Cardiology Service | 301-295-7839 | todd.villines@us.army.mil |
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| BG002 | 3 - Warfarin Use Chronic | Warfarin use >24 months |
| BG003 | Total | Total of all reporting groups |
| Participants |
|
| Age Continuous | Mean | Standard Deviation | years |
|
| Sex: Female, Male | Count of Participants | Participants |
|
| Region of Enrollment | Number | participants |
|
| ID |
|---|
| Title |
|---|
| Description |
|---|
| OG000 | Warfarin Use Short Duration | Warfarin use for less than 6 months |
| OG001 | 2 - Warfarin Use Intermediate | Warfarin use for 6 to 24 months in duration |
| OG002 | 3 - Warfarin Use Chronic | Warfarin use >24 months |
|
|
| Secondary | International Normalized Ratio | The International Normalized Ratio (INR) is a standardized lab value that measures the intensity of anticogulation using warfarin. It is used to monitor patients taking warfarin. | Posted | Mean | Standard Deviation | ratio | EBCT scan is done at time of enrollment of patient into 1 of 3 groups based on warfarin use duration: <6 months; 6-24 months; >24 mos. |
|
|
|
| 0 |
| 31 |
| 0 |
| 31 |
| EG001 | 2 - Warfarin Use Intermediate | Warfarin use for 6 to 24 months in duration | 0 | 11 | 0 | 11 |
| EG002 | 3 - Warfarin Use Chronic | Warfarin use >24 months | 0 | 28 | 0 | 28 |
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