Try our beta test site
IMPORTANT: Listing of a study on this site does not reflect endorsement by the National Institutes of Health. Talk with a trusted healthcare professional before volunteering for a study. Read more...

The Antiaggregation Monitoring (TAM) Registry (TAM)

The recruitment status of this study is unknown. The completion date has passed and the status has not been verified in more than two years.
Verified November 2010 by University Hospital Freiburg.
Recruitment status was:  Recruiting
Information provided by:
University Hospital Freiburg Identifier:
First received: March 30, 2011
Last updated: April 14, 2011
Last verified: November 2010
The purpose of this study is to investigate the incidence of acetylsalicylic acid resistance (ASA-R) among patients under chronic acetylsalicylic acid(ASA) treatment seen at our outpatient clinic.

Condition Intervention
Aspirin Causing Adverse Effects in Therapeutic Use
Other: Measurement of platelet anti-aggregation

Study Type: Observational
Study Design: Observational Model: Cohort
Time Perspective: Cross-Sectional
Official Title: Acetylsalicylic Acid in Outpatient Practice - Results From The Antiaggregation Monitoring (TAM) Registry

Further study details as provided by University Hospital Freiburg:

Primary Outcome Measures:
  • Whole blood impedance platelet aggregometry to assess acetylsalicylic acid resistance rates [ Time Frame: 6 months ]

Estimated Enrollment: 200
Study Start Date: November 2010
Estimated Study Completion Date: April 2011
Estimated Primary Completion Date: April 2011 (Final data collection date for primary outcome measure)
Groups/Cohorts Assigned Interventions
TAM patients
All consecutive patients under chronic ASA treatment (100mg/d) seen at our outpatient clinic.
Other: Measurement of platelet anti-aggregation
Whole blood impedance platelet aggregometry was performed with the Multiplate analyzer (Dynabyte, Munich, Germany) to test the response to ASA with arachidonic acid as the trigger.

Detailed Description:

Acetylsalicylic acid (ASA) resistance (R) is best defined as an ineffective inhibition of the platelet cyclooxygenase (COX)-1 pathway, and has been reported in 1 to 61 % of patients treated with ASA. Impaired response to ASA has been associated with an increased risk of ischemic events in patients with known coronary artery disease. We sought to investigate the incidence of ASA-R in clinical practice.

All consecutive patients under chronic ASA treatment (100mg/d) seen at our outpatient clinic were systematically included in the registry. All patients were on acetylsalicylic acid for CAD for at least 1 month. Patients were informed of ASA testing at start of consultation in the outpatient clinic. Eligible patients provided written informed consent. Peripheral venous blood samples were analyzed using the whole blood impedance platelet aggregometry Multiplate analyzer. The Multiplate analyzer device allows to measure platelet aggregation by the attachment of platelets to two silver coated copper electrodes leading to a rise of electrical resistance in the sample. The measurements are expressed as arbitrary aggregation units (AU) and the manufacturers defined cutoffs were used: normal values were 76-136 AU, partial antiaggregation was defined as ASA values between 31 and 75 AU and complete antiaggregation was defined as ASA values < 31 AU.


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
All consecutive patients under chronic ASA treatment seen at our outpatient clinic

Inclusion Criteria:

  • patients under chronic ASA treatment for more then one month

Exclusion Criteria:

  • concomitant use of nonsteroidal anti-inflammatory drugs (NSAIDs)
  • thrombocytopenia
  • thrombocytosis
  • age <18 years
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01329224

Contact: Stéphane Cook, Prof. 0041264268140
Contact: Markus Oberhaensli, MD 0041264268141

Service de Cardiologie, Hôpital Cantonal Fribourg Recruiting
Fribourg, FR, Switzerland, 1708
Principal Investigator: Stéphane Cook, MD         
Sponsors and Collaborators
University Hospital Freiburg
Principal Investigator: Stéphane Cook, Prof Fribourg University
  More Information

Responsible Party: Prof. Stéphane Cook, University Freibourg Identifier: NCT01329224     History of Changes
Other Study ID Numbers: 242/10A
Study First Received: March 30, 2011
Last Updated: April 14, 2011

Keywords provided by University Hospital Freiburg:
acetylsalicylic acid resistance

Additional relevant MeSH terms:
Anti-Inflammatory Agents, Non-Steroidal
Analgesics, Non-Narcotic
Sensory System Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Anti-Inflammatory Agents
Antirheumatic Agents
Fibrinolytic Agents
Fibrin Modulating Agents
Molecular Mechanisms of Pharmacological Action
Platelet Aggregation Inhibitors
Cyclooxygenase Inhibitors
Enzyme Inhibitors
Antipyretics processed this record on April 27, 2017