Some studies have found that patent foramen ovales (PFOs) are more common in people with unexplained strokes and migraines with aura. People who have a PFO are slightly more likely to have a stroke than people who don't.A PFO is more likely to be involved in a stroke of a younger adult. This does not mean that everyone who has PFO will experience a stroke or mini-stroke. PFO could be a cause or coincidence of stroke. A patent foramen ovale is a small hole in the heart that may increase risk of stroke. Learn about how a PFO affect stroke risk. Patent foramen ovale (PFO) or hole in the heart, affects millions of people and can cause a stroke. PFOs can let small blood clots reach your brain, causing a stroke. PFO's don't cause strokes.