The primary aim of this research project is to determine the optimal time for antithrombotic agent initiation post ischemic stroke without resulting hemorrhagic conversion. We hypothesize that not only is hemorrhagic conversion risk often inaccurately estimated, but also that antiplatelet agents and anticoagulants may pose similar risk of hemorrhagic conversion, particularly when initiated seven days post ischemic stroke. This risk potentially outweighs their protective effects against recurrent stroke. We are in the process of identifying patients with hemorrhagic conversion of ischemic stroke at Thomas Jefferson University Hospital and will analyze the type and timing of antithrombotic agents. Additional risk factors studied include mechanism and location of stroke, infarct volume, atrial fibrillation, LDL levels, statin therapy, chronic diseases, and substance abuse. We will perform a multivariate analysis to evaluate for associations among the risk factors. Due to unexpectedly lower rates of patients with hemorrhagic conversion and difficulties obtaining data due to coding variability, we do not currently have sufficient data for a full analysis (N=50). Interesting trends seen in the data include that 22 out of our 50 patients bled on aspirin monotherapy. However, there is a need for more patient data to begin drawing statistically significant conclusions. Once data collection is completed, we anticipate identifying specific antithrombotic therapies and timing of therapies that have strong associations with hemorrhagic conversion. This will help to develop evidence-based guidelines for management of acute ischemic stroke treatment at a large comprehensive stroke center with diverse patient population