Some studies have found that patent foramen ovales (PFOs) are more common in people with unexplained strokes and migraines with aura. PFO could be a cause or coincidence of stroke.Patent foramen ovale (PFO) is a hole between your heart's upper chambers. 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. However, in a small number of patients, a PFO may permit blood clots to cross from the right side of the heart to the left side, resulting in a stroke. Patent foramen ovale (PFO) or hole in the heart, affects millions of people and can cause a stroke. Stroke is the major potential complication of PFO. People who have a PFO are slightly more likely to have a stroke than people who do not. PFO's don't cause strokes.