Aspirin Resistance and Stroke Risk: Platelet Function Analysis in Patients With Ischemic Events


Phase 2/3 Results

Trial Description

The purpose of this study is to determine if PFA results correlate with ischemic event outcomes as well as bleeding complications. Hypothesis is antiplatelet agents will be more efficacious if they are administered in a dose-adjusted manner using PFA results as a guide.

Detailed Description

Atherothrombotic disease is a leading killer of adults throughout the world. The current mainstay for the prevention of ischemic vascular events is the use of aspirin Antiplatelet agents are used routinely for the primary and secondary prevention of vascular events in patients with a prior history of stroke, TIA, or at high risk for the development of cerebrovascular disease. Numberous individual studies and meta-analyses have shown that essentially all of the oral antiplatelet agents have limited efficacy, with relative risk reductions in the range of 20-35%. The purpose of this study is to perform serial platelet function assays (PFAs) on patients with cerebrovascular disease who are taking antiplatelet agents and perform a pilot study to determine the feasibility of administering ASA as a dose adjusted medication using PFA. The long term goal of this study is to determine whether antiplatelet therapy will be more efficacious and/or safer if it is administered in a dose-adjusted manner.



  • Clopidogrel (Plavix┬«)Drug
    Other Names: Plavix, Clodelib, Clovelen
    Intervention Desc: Clopidogrel 75 mg QD
    ARM 1: Kind: Experimental
    Label: Clopidogrel 75 mg
    Description: Clopidogrel 75 mg daily
  • Aspirin, clopidogrel Drug
    Other Names: Plavix
    Intervention Desc: ASA 81 mg QD, ASA 325 mg QD, Clopidogrel 75 mg QD
  • Aspirin 81 mg Drug
    Other Names: baby aspirin
    Intervention Desc: Aspirin 81mg QD
    ARM 1: Kind: Experimental
    Label: Aspirin 81 mg
    Description: open-label Aspirin 81 mg daily
  • Aspirin >300 mg Drug
    Other Names: Acetylsalicylic Acid; ASA
    Intervention Desc: Aspirin >300 mg QD
    ARM 1: Kind: Experimental
    Label: Aspirin > 300mg
    Description: open-label Aspirin over 300 mg daily

Trial Design

  • Allocation: Non-Randomized
  • Masking: Open Label
  • Purpose: Treatment
  • Endpoint: Safety/Efficacy Study
  • Intervention: Parallel Assignment


Type Measure Time Frame Safety Issue
Primary PFA results correlating with ischemic events and bleeding complications 4 years Yes
Primary PFA1 3-6 months (At the time of regularly scheduled clinic follow-up visits) Yes