Patent foramen ovale (PFO) is a potential cause of cryptogenic stroke. Three previous randomized trials of transcatheter PFO closure did not show a lower risk of recurrent stroke with PFO closure than with medical therapy in their primary intention-to-treat analyses; however, secondary analyses suggested a benefit with PFO closure. The goal of the Gore REDUCE Clinical Study was to determine the efficacy and safety of PFO closure (with two versions of a closure device) plus antiplatelet therapy, as compared with antiplatelet therapy alone, for the prevention of recurrent clinical ischemic stroke or new brain infarction in patients with PFO who had had a cryptogenic stroke.