The doctor then guides an implant through the catheter to the hole, where it will expand and seal the PFO closed. Because PFO does not typically cause symptoms other than migraine, stroke or TIA, doctors usually find it while investigating another health concern.A review of atrial septal closure, including the surgical evolution and the subsequent progression of transcatheter device closure. A patent foramen ovale (PFO) Patent foramen ovale closure with the Intrasept occluder: complete 6-56 months follow-up of 247 patients after presumed paradoxical embolism. Following an uncomplicated procedure, patients were discharged the following day.