Patent foramen ovale and stroke risk: incidental finding or causal culprit?

Between 17 and 27% of the population has a patent foramen ovale (PFO) based on autopsy studies. Given these percentages, a PFO could be considered a variant of normal cardiac anatomy and not an anomaly. As this anatomy is so prevalent in the normal population, it is likely that there are other factors involved in patients who have a PFO and a stroke. This review will evaluate the existing literature on PFO and stroke to determine what constitutes an increased risk of embolic events in patients with PFO. Given the paucity of existing literature, it is clear from this review that there is a vital need for randomized clinical trials to answer important questions, including what constitutes high-risk anatomy and optimal treatment for patients for the prevention of recurrent stroke.