Resistance to Aspirin and/or Clopidogrel Among Patients With PAD.

NCT ID: NCT00262561

Last Updated: 2014-01-28

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: PHASE4
• Total Enrollment: 263 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2006-01-31
• Study Completion Date: 2008-01-31

Brief Summary

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.

Detailed Description

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.

Main objectives:

• 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.

Methods:

Platelet activity is measured by the PFA-100 (Dade Behring) and by traditional turbidimetric aggregation.

Endpoints:

Myocardial infarction, unstable angina, cerebral infarction, transitory cerebral ischaemia, sudden deterioration of symptoms, percutaneous or surgical vascular intervention, amputation, death.

Conditions

Intermittent Claudication

Study Design

• Allocation Method: NON_RANDOMIZED
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: DIAGNOSTIC
• Blinding Strategy: NONE

Study Groups

Aspirin

All participants get Aspirin, and platelet reactivity measurements are performed.

Group Type: ACTIVE_COMPARATOR

Aspirin

Intervention Type: DRUG

The effect of Aspirin on platelet function was assessed.

Interventions

Aspirin

The effect of Aspirin on platelet function was assessed.

Intervention Type: DRUG

Eligibility Criteria

Inclusion Criteria

• Atherosclerosis of the lower limbs, defined by one of the following criteria: Ankle-Brachial Pressure Index (ABPI)< 0.9, intermittent claudication, ischaemic pain at rest, ischaemic ulcers or gangrene.
• Age > 18 years
• For fertile women: Use of safe contraception (intrauterine contraceptive device, the pill, hormonal skin patches, progestogen injections, progestogen implant, vaginal ring)

Exclusion Criteria

• Allergy to either Aspirin or Clopidogrel
• Known bleeding disorder
• Platelet count < 140 mia/L or > 400 mia/L
• Intake of NSAID's, SSRI's or Dipyridamol within the preceding 14 days
• Not radically treated gastrointestinal ulceration within the last 6 month
• Greater surgical procedures performed within the last 3 month
• Severe renal disease
• Severe hepatic disease
• Breast feeding
• Pregnancy

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Danish Heart Foundation

OTHER

Sponsor Role: collaborator

Aalborg University Hospital

OTHER

Sponsor Role: lead

Responsible Party

Esben Hjorth Madsen

M.D.

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Nils Johannesen, MD

Role: PRINCIPAL_INVESTIGATOR

Department of Vascular Surgery, Aalborg Hospital

Locations

Department of Vascular Surgery, Aalborg Hospital

Aalborg, , Denmark

Countries

Denmark

Other Identifiers

2005-003844-68

Identifier Type: -

Identifier Source: org_study_id