Aspirin ResistanceNCT01432652
The Efficacy of Aspirin in the Postoperative Period in Vascular Surgery
An observational study of Aspirin Resistance, run by University of Lausanne Hospitals at 1 site in Switzerland.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Aspirin Resistance
- How many people
- 45 participants
- Where
- 1 siteSwitzerland
- Study dates
- Sep 2011to May 2014
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Vascular surgery patients
Who may be able to join
- Patient undergoing peripheral vascular or abdominal aorta surgery.
- Patient aged 18 years or older.
- Patient treated by aspirin.
Who cannot join
- 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.
Trial locations and contacts
1 site in 1 country.
Switzerland1 site
University of Lausanne Hospitals
Lausanne, Canton of Vaud, 1011
About this study
Official title: Efficacité du Traitement antiagrégant Par Acide acétylsalicylique en Chirurgie Vasculaire mesurée Par agrégométrie Par impédance
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.
Read the 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.
- Conditions
- Aspirin Resistance
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| vascular surgery | Patients undergoing vascular surgery |
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Sep 2011 (estimated)
- Study startSep 2011
- Primary completionJan 2014
- Study completionMay 2014
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Aspirin ResistanceStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 45 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Lausanne Hospitals
- Sponsor type
- University, hospital or other
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT01432652
- Sponsor's protocol ID
- 176/11
- Status last verified
- Sep 2011
- First submitted
- 12 Sep 2011
- Last updated
- 29 Jul 2015
- Results posted
- No
- Data monitoring committee
- No
Study at a glance
From the registry record, last updated by the sponsor on 29 Jul 2015. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Efficacité du Traitement antiagrégant Par Acide acétylsalicylique en Chirurgie Vasculaire mesurée Par agrégométrie Par impédance
- ClinicalTrials.gov ID
- NCT01432652
- Acronym / sponsor ID
- 176/11
- Conditions
- Aspirin Resistance
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 45 participants (actual)
- Lead sponsor
- University of Lausanne HospitalsUniversity, hospital or other
- Study start
- Sep 2011
- Primary completion
- Jan 2014 (actual)
- Study completion
- May 2014 (actual)
- First posted
- 13 Sep 2011 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
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.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| vascular surgery | – | –Patients undergoing vascular surgery |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Vascular surgery patients
Key inclusion criteria (3 listed)
- Patient undergoing peripheral vascular or abdominal aorta surgery.
- Patient aged 18 years or older.
- Patient treated by aspirin.
Key exclusion criteria (8 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Not reported in the source record.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 Jul 2015.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Aspirin Resistance, run by University of Lausanne Hospitals at 1 site in Switzerland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 29 Jul 2015. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 29 Jul 2015.