Transcatheter Closure of Patent Foramen Ovale.

P atent foramen ovale (PFO), the most common postnatal residue of the fetal circulation, has for many years been considered to have almost no clinical relevance. In an autopsy study from the Mayo Clinic, PFO was found in 27% of 965 normal human hearts, with an incidence declining with increasing age (34% in the first three decades and 20% in the ninth and 10th decades).' PFO size ranged between 1 and 19 mm (mean, 4.9 mm) and showed a tendency for largersized communications that present in older age groups. There were no significant differences in incidence or size between males and females. Similar findings had been reported earlier by Thompson and Evans,2 who observed a "pencil patent" PFO in 6% and a "probe patent" PFO in 29% of 1,100 consecutive necropsies. A PFO is not associated with typical findings detectable by physical examination or basic laboratory tests. It can be diagnosed by cardiac catheterization or by detection of right-to-left echocardiographic contrast passage using transcranial Doppler ultrasound.3 Currently, however, the methods of choice for PFO diagnosis combine two-dimensional contrast45 or color Doppler6 echocardiography, with the transesophageal approach being more accurate than the transthoracic technique.7-9 Transesophageal echocardiography has an acceptably low risk for performance even in elderly or neurologically impaired patients,10 and the biplane mode in particular provides superb images of the atrial septum in virtually all patients. Consequently, PFO can be detected during life in a percentage of patients approaching that at autopsy.