- Use of anticoagulation therapy, including warfarin with a target international normalized ratio (INR) of 2 or greater Anti-platelet therapy (e.g. aspirin or clopidogrel) is permitted, as is heparin given during hemodialysis. Low-dose warfarin is permitted and defined as the presence of at least two INR values less than or equal to 1.5 during the 120 days prior to enrollment and no values exceeding 1.5 at any time after 120 days prior to enrollment.