It is estimated that there are about 1 million patients with ischemic stroke and transient cerebral ischemia in the United States each year, of which 60% are caused by cerebrovascular lesions and 40% have no evidence of cerebrovascular lesions, and of the latter, about 50% have foramen ovale nonocclusion, while the rate of foramen nonocclusion in the control group is only 10-15%. In other words, approximately 100-200,000 cerebrovascular accidents per year in the United States may be associated with patent foramen ovale. The foramen ovale is located in the lower and middle part of the interatrial septum and is the space between two overlapping membranous tissues (foramen ovale flaps), which is a normal pathway for blood circulation during fetal life. After birth, the reversal of atrial pressure forces the foramen ovale valve to close, and after a period of time the foramen ovale valve adheres and fuses together to permanently close the atrial septal traffic. For various reasons, the foramen ovale valve does not fuse sufficiently after birth, so that a small amount of shunt still exists at the site of the foramen ovale. In the past, it was thought that the amount of shunt in the foramen ovale was small and not clinically significant, but recently it is thought that the foramen ovale is associated with “paradoxical embolism”, especially in some cases of unexplained stroke and migraine. Therefore, interventional occlusion or surgery should be considered in patients with the following conditions: 1) large diameter of the foramen ovale; 2) recurrent cerebrovascular events or MRI confirmed multiple cerebral infarcts, especially if there is an increase in abdominal pressure or cough before the stroke; 3) significant right-to-left shunt; 4) foramen ovale with atrial septal tumor.