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The Efficacy of Aspirin in the Postoperative Period in Vascular Surgery

This study has been completed.
Sponsor:
ClinicalTrials.gov Identifier:
NCT01432652
First Posted: September 13, 2011
Last Update Posted: July 29, 2015
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.
Information provided by:
University of Lausanne Hospitals
  Purpose
The purpose of this study is to determine the incidence of aspirin resistance in the population of vascular surgery patients; and to evaluate the changes in the efficacy of aspirin in the first five postoperative days.

Condition
Aspirin Resistance

Study Type: Observational
Study Design: Observational Model: Cohort
Time Perspective: Prospective
Official Title: Efficacité du Traitement antiagrégant Par Acide acétylsalicylique en Chirurgie Vasculaire mesurée Par agrégométrie Par impédance

Further study details as provided by University of Lausanne Hospitals:

Biospecimen Retention:   Samples With DNA
whole blood

Enrollment: 45
Study Start Date: September 2011
Study Completion Date: May 2014
Primary Completion Date: January 2014 (Final data collection date for primary outcome measure)
Groups/Cohorts
vascular surgery
Patients undergoing vascular surgery

Detailed Description:

About 15% of the general population shows resistance to the antiplatelet effects of aspirin, due to genetic polymorphisms and other factors. This resistance is a cause of increased myocardial infarction and death in patients undergoing percutaneous coronary interventions. Aspirin resistance can be detected by whole blood impedance aggregometry using the Multiplate® analyzer. The population of patients undergoing vascular surgery is at particular risk of suffering myocardial infarction in the perioperative period because of the high prevalence of risk factors. Most of these patients are treated by aspirin, as a measure of primary or secondary prevention. In this study we aim to establish baseline aspirin efficacy, as measured by the Multiplate® analyzer, in this high-risk population and evaluate the changes in aspirin efficacy over the first five days of the postoperative period. It is our hypothesis that the state of chronic inflammation, accompanying severe, generalized atherosclerosis results in a higher incidence of aspirin resistance in this population. Also, the surgical trauma and postoperative thrombocytosis may reduce the efficacy of aspirin in the postoperative period, partially explaining the increased incidence of postoperative myocardial infarction in this population.

In whole blood impedance aggregometry, the electrical impedance of the blood sample is measured by placing two electrodes in the recipient. After the addition of a platelet activator, the impedance will increase as platelets accumulate on the electrodes surfaces. Several activators, testing the patency of different platelet receptors can be used.

In this study, blood will be drawn on the day of surgery, and daily until the fifth postoperative day. Arachidonic acid, ADP, TRAP-6 and collagen will be used as activators. The first specifically tests the platelets reactivity to thromboxane A2. Aspirin inhibits this pathway, and the increase in impedance should therefore be limited in patients treated by this drug. The three other tests will be performed to evaluate the evolution of overall platelet reactivity in the postoperative period.

  Eligibility

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Probability Sample
Study Population
Vascular surgery patients
Criteria

Inclusion Criteria:

  • Patient undergoing peripheral vascular or abdominal aorta surgery.
  • Patient aged 18 years or older.
  • Patient treated by aspirin.

Exclusion Criteria:

  • Incapacity to understand and consent to study.
  • Patient undergoing emergency surgery.
  • Patient treated by a cox-inhibitor other than aspirin.
  • Patient treated by omega-3-fatty acids.
  • Patient treated by ADP or GPIIb/IIIa receptor inhibitor.
  • Known coagulopathy, thrombopenia, thrombopathia or congenital or acquired thrombasthenia.
  • Terminal renal insufficiency.
  • Hepathic insufficiency.
  Contacts and Locations
Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01432652


Locations
Switzerland
University of Lausanne Hospitals
Lausanne, Vaud, Switzerland, 1011
Sponsors and Collaborators
University of Lausanne Hospitals
  More Information

ClinicalTrials.gov Identifier: NCT01432652     History of Changes
Other Study ID Numbers: 176/11
First Submitted: September 12, 2011
First Posted: September 13, 2011
Last Update Posted: July 29, 2015
Last Verified: September 2011