In a patient with cryptogenic stroke while on antecedent aspirin 81 mg, how do you decide between single antiplatelet therapy, dual antiplatelet therapy, or antiplatelet agent combined with anticoagulation such as rivaroxaban 2.5 mg BID?  

This question assumes that a thorough workup has been completed, and the patient does not have paroxysmal a fib, a PFO, an intracranial stenosis, a hypercoagulable state, or vasculitis. This workup is the most important issue. If all is negative, and the stroke is relatively minor (NIHSS less than o...