Patent Foramen Ovale in Cryptogenic Stroke Study "PICSS"


Phase 4 Results

Trial Description

The study sought to assess the rate of recurrent stroke and death in stroke patients with a patent foramen ovale randomized to treatment with warfarin or aspirin. This was a multicenter study conducted at 48 U.S. Institutions.



  • Aspirin (stroke prevention) Drug
    Intervention Desc: Antiplatelet agent; inhibits thromboxane A2
  • Warfarin (Coumadin┬«)Drug
    Intervention Desc: Warfarin once a day, titrated to obtain an INR of 1.4 to 2.8; placebo aspirin once a day
    ARM 1: Kind: Experimental
    Label: Warfarin
    Description: Warfarin (target International Normalized Ratio: 1.4 to 2.8) plus placebo aspirin
  • Aspirin Drug
    Intervention Desc: Aspirin 325 mg once a day; placebo warfarin once a day
    ARM 1: Kind: Experimental
    Label: Aspirin
    Description: Aspirin 325 mg plus placebo warfarin

Trial Design

  • Allocation: Randomized
  • Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor)
  • Purpose: Prevention
  • Endpoint: Efficacy Study
  • Intervention: Parallel Assignment

Patient Involvement

Following enrollment in the study, patients received TE to assess whether or not they had a PFO, and their baseline strokes were subtyped by a neurologist. They were then randomized to receive either 325 mg aspirin and a warfarin-resembling placebo (n = 318) or 2 mg warfarin and an aspirin-resembling placebo (n = 312). They were briefly evaluated wither over the phone or in person every month, and received detailed examinations in person every quarter for two years.


Type Measure Time Frame Safety Issue
Primary Recurrent ischemic stroke or death.
Primary Recurrent ischemic stroke and death 2 years No