- Disease or medication-related disorder of coagulation (i.e., elevated partial thromboplastin time (PTT) >13.8 seconds, international normalized ratio (INR) >1.2, or low platelet count <150x109/L). Patients on coumadin, heparin products, and novel oral anticoagulants will be excluded. Antiplatelet medications (e.g. aspirin, clopidogrel) are permitted as long as the aforementioned coagulation labs are within the specified range.