Why does opening the foramen ovale cause pulmonary hypertension and migraine?

The foramen ovale is a normal physiological structure of the heart. Normal people will automatically close after birth. If the foramen ovale is not closed until adulthood, it is likely to cause emboli to pass directly through the foramen ovale and enter the pulmonary artery and brain with the blood, which will induce pulmonary hypertension and cerebral infarction, so migraine symptoms appear.