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Warfarin and Coronary Calcification Project (WACC)

This study has been completed.
Information provided by (Responsible Party):
Todd C. Villines, Walter Reed Army Medical Center Identifier:
First received: March 24, 2009
Last updated: August 23, 2012
Last verified: August 2012
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.

Coronary Calcification

Study Type: Observational
Study Design: Observational Model: Cohort
Time Perspective: Prospective
Official Title: Warfarin and Coronary Calcification Project

Resource links provided by NLM:

Further study details as provided by Todd C. Villines, Walter Reed Army Medical Center:

Primary Outcome Measures:
  • 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 [ Time Frame: 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. ]
    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.

Secondary Outcome Measures:
  • International Normalized Ratio [ Time Frame: 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. ]
    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.

Enrollment: 70
Study Start Date: May 2004
Study Completion Date: January 2010
Primary Completion Date: January 2010 (Final data collection date for primary outcome measure)
Warfarin use < 6 months
Warfarin use 6-24 months
Warfarin use >24 months


Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
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).

Inclusion Criteria:

  • Age 18 years of age or older
  • Patients referred to begin or already treated with warfarin anticoagulation therapy.

Exclusion Criteria:

  • Known prior myocardial infarction or coronary heart disease
  • History of advanced chronic kidney disease manifested by serum creatinine>2 or calculated glomerular filtration rate (GFR)<30
  • History of hyperparathyroidism
  • Current hypercalcemia
  • Current hyperphosphatemia
  • Uncertain duration of warfarin therapy
  • Lack of records documenting international normalized ratio (INR) during therapy
  Contacts and Locations
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Please refer to this study by its identifier: NCT00868712

United States, District of Columbia
Walter Reed Army Medical Center
Washington, District of Columbia, United States, 20307
Sponsors and Collaborators
Walter Reed Army Medical Center
  More Information

Additional Information:
Responsible Party: Todd C. Villines, Director, Cardiovascular Research, Walter Reed Army Medical Center Identifier: NCT00868712     History of Changes
Other Study ID Numbers: WU# 04-12020
Study First Received: March 24, 2009
Results First Received: February 2, 2010
Last Updated: August 23, 2012

Keywords provided by Todd C. Villines, Walter Reed Army Medical Center:
coronary calcification
vitamin K dependent proteins

Additional relevant MeSH terms:
Calcium Metabolism Disorders
Metabolic Diseases
Anticoagulants processed this record on May 25, 2017