Danish Aspirin Resistance Trial - Pilot Study

Study Overview
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Brief Summary
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Despite treatment with aspirin a large number of patients suffer a myocardial infarction. It has been speculated that these patients might be resistant to aspirin, and studies have indicated that this phenomenon is related to a less favourable prognosis. At present, no international consensus exists on how to measure aspirin resistance. The purpose of this study is to compare different methods for detecting aspirin resistance. A classic but cumbersome way of evaluating platelet function will be compared to newer, easy-handling point-of-care tests. We hypothesize that one or more point-of-care tests will prove to be superior to the classic platelet function test in detecting aspirin resistance.

Detailed Description
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Platelets play a major role in arterial thrombus formation - the cause of cardiovascular death, acute myocardial infarction and ischemic stroke and the number one killer in the Western World. Binding the COX enzyme platelet aggregation is inhibited by aspirin, and as prophylaxis against death, myocardial infarction and stroke aspirin is the most widely used drug worldwide. Low dose aspirin has been shown to improve outcome in patients with ischemic heart disease, but approximately 12% of these patients will suffer from a vascular event during a 2 year follow-up period despite aspirin therapy. It has been speculated that these patients might be resistant to the antiaggregatory effect of aspirin, and a diminished response to aspirin has been correlated with a less favourable outcome. However, at present no international consensus exists on how to measure aspirin resistance. Comparisons: The platelet aggregation in patients with ischemic heart disease on chronic, low dose aspirin is compared to platelet aggregation i healthy volunteers evaluated with different tests. The traditional way of evaluating platelet function, Platelet Aggregometry a.m. Born, will be compared to 3 point-of-care tests (VerifyNow, PFA-100 and Multiplate Whole Blood Aggregometer) and to urin- and serum thromboxane metabolites as a measure of COX inhibition.

Official Title
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Comparative Evaluation of Aspirin Resistance With Point-of-Care Testing - Danish Aspirin Resistance Trial (DANART) - Pilot Study

Conditions
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Drug Resistance

Intervention / Treatment
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* Drug: acetylsalicylic acid


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ischemic heart disease verified with a coronary angiogram treatment with 75 mg aspirin once daily Exclusion Criteria: ischemic vascular event within the previous 12 months percutaneous coronary intervention or coronary artery by-pass grafting within the previous 12 months treatment with NSAID, clopidogrel, ticlopidine, dipyridamole, warfarin or any other drug affecting platelet aggregation platelet count < 120 x 10^9/l not able to give informed consent

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Intervention/Treatment |
| --- |
|Drug: acetylsalicylic acid|nan|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Platelet aggregation (as determined by 3 point-of-care tests and by serum-thromboxane A2 + urine 11-dehydro thromboxane B2) is measured once daily for 4 days after one week of treatment with aspirin 75 mg/day |  |  | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Platelets, Aspirin Resistance, Platelet aggregation