1. Patients with stroke or asymptomatic cerebral infarction without clear risk factors; 2. Patients with recurrent episodes of transient aphasia, paresis or sensory disturbances; 3. Patients with migraine, especially migraine with aura; 4. Patients with syncope. PFO is a congenital developmental defect of the interatrial septum. A large number of studies have shown that PFO is closely related to migraine, cryptogenic stroke, unexplained syncope and episodic amnesia; 48% of migraine patients with aura have PFO; patients with migraine with aura have three times the chance of having PFO than non-migraine patients. The mechanism by which PFOs cause headaches may be: tiny blood clots or headache-triggering substances such as 5-hydroxytryptamine, which cause headaches if they enter the brain through the PFO. Blood clots in the venous system can also enter the brain through the PFO and cause cerebral embolism. At the same time, the unclosed foramen ovale opens during deep breathing and coughing, and microscopic blood clots from the venous system enter the circulation through the unclosed foramen ovale, causing cerebral embolism and becoming a risk factor for stroke. This shows that unclosed foramen ovale is an important risk factor and one of the causes of migraine and stroke. Foaming test is a sensitive and effective test for the diagnosis of PFO. Experts recommend that those patients with unexplained migraine, syncope, episodic amnesia, stroke, transient ischemic attack, asymptomatic cerebral infarction without either significant head and neck artery disease or embolism-prone arrhythmias should undergo a TCD foaming test to be able to detect where the true cause lies. This test has the advantages of being noninvasive, safe, does not require an allergy test, the contrast agent is physiologically compatible, highly sensitive, highly specific, allows semi-quantitative assessment of fractional flow, and is inexpensive. In conclusion: In the past, it was thought that small patent foramen ovale (PFO) and atrial septal defects did not require surgical treatment, but this view has recently changed, and smaller defects of the atrial septum may lead to headache, syncope and even the risk of stroke, so they are more aggressively treated surgically. In our department, we adopt the ultra-minimally invasive method of trans-femoral esophageal ultrasound-guided placement of a blocker in suitable patients, with only a 3-5 mm incision in the leg groin, without X-ray exposure, which is safe, easy and effective!