Patent foramen ovale (PFO) is common in both the general population, as well as in patients with cryptogenic stroke, with an estimated prevalence somewhere between 15-35%. Recurrent neurovascular events, both recurrent ischemic stroke as well as transient ischemic attacks, are frequent in these patients, but it is not clear whether patients with PFOs have an increased rate of recurrent events compared to those patients who do not have PFOs.