Patent foramen ovale closure to treat migraine headache

摘要

The foramen ovale is a slit-like valve between the septum primum and septum secundum that exists in the mammalian fetal heart. This valve opening provides a right-to-left heart shunt so that oxygenated blood from the placenta can bypass the pulmonary circulation and flow directly to the fetal brain. After birth, the two septa fuse to complete the separation of the left and right atria but the foramen ovale remains patent in about 20% of the adult population.1 This defect was thought to be of little clinical significance; however, patent foramen ovale (PFO) has recently been implicated in several diseases, including platypnea-orthodeoxia syndrome and neurologic decompression illness in scuba divers, and case-control studies have indicated a role in cryptogenic stroke. These conditions are believed to occur when the PFO allows right-to-left shunting of blood associated with arterial desaturation, nitrogen bubbles or blood clots. Cryptogenic stroke describes a neurologic deficit that has no identifiable cause. One of the theoretical causes for such an event is paradoxical embolism-a small clot that bypasses the pulmonary circulation and enters the systemic circulation, where it lodges in the brain. This proposed mechanism would support the theory that people with a PFO have increased stroke risk. Recently, PFO has received attention for its possible association with migraine headaches. In this Viewpoint, we discuss the possibility that the majority of migraine headache could be treated by closing the PFO passageway through the heart.