Question: why does pfo cause migraines?
Answer: Possible pathophysiological mechanisms of patent foramen ovale (PFO) in migraine. Another postulated mechanism related to the PFO–migraine axis is that transient hypoxemia due to shunting of blood through the PFO causes microinfarcts in the brain, leading to irritation and a tendency for migraine (Table 1) [4], [6].