Resistance to Aspirin and/or Clopidogrel Among Patients With PAD.
263 patients with peripheral atherosclerosis were examined to evaluate the activity of the platelets during the standard treatment, including aspirin. A subgroup of 43 received 600 mg of clopidogrel 2 h before platelet reactivity analysis.
The main hypothesis is that high platelet activity at the beginning of the study is associated with a higher risk of atherothrombosis. Follow up time is 5 years.
|Study Design:||Allocation: Non-Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Diagnostic
|Official Title:||Prevalence of Resistance to Aspirin and/or Clopidogrel Among Patients With PAD. Prognostic Significance of Resistance to Aspirin|
- Myocardial infarction, Unstable angina, Cerebral infarction, Transitory cerebral ischaemia, Percutaneous or surgical vascular intervention, Sudden deterioration of symptoms, Amputation, Death. [ Time Frame: 5 years ] [ Designated as safety issue: No ]
|Study Start Date:||January 2006|
|Study Completion Date:||January 2008|
|Primary Completion Date:||January 2008 (Final data collection date for primary outcome measure)|
Active Comparator: Aspirin
All participants get Aspirin, and platelet reactivity measurements are performed.
The effect of Aspirin on platelet function was assessed.
Patients with peripheral atherosclerosis are at high risk of atherothrombosis, mainly heart attack and stroke. The medical treatment of these patients include platelet inhibiting drugs, usually aspirin, to reduce the risk of ischemic events. Clopidogrel is another platelet inhibiting drug, which is prescribed less often, primarily because of the high costs compared to aspirin.
Phenomena of 'resistance' to these drugs have been described by numerous investigators. Essentially resistance means that the effect of the drug described is less than expected or missing, as measured by various laboratory methods. We do not know which way resistance is best described, but it has been described that patients who are 'resistant' to either drug are less protected against future heart attacks or strokes.
- To measure the activity of platelets in these patients during aspirin treatment.
- To measure the activity of platelets in a minor population of these patients during clopidogrel treatment.
- To evaluate the prognostic significance of resistance to aspirin in these patients.
Platelet activity is measured by the PFA-100 (Dade Behring) and by traditional turbidimetric aggregation.
Myocardial infarction, unstable angina, cerebral infarction, transitory cerebral ischaemia, sudden deterioration of symptoms, percutaneous or surgical vascular intervention, amputation, death.
|Department of Vascular Surgery, Aalborg Hospital|
|Aalborg, Denmark, 9000|
|Principal Investigator:||Nils Johannesen, MD||Department of Vascular Surgery, Aalborg Hospital|