Objectives:To observe the incidence of residual shunt post patent foramen ovale(PFO)closure and the effect of PFO closure in these migraine patients at one year after PFO. Methods:This retrospective study included patients who underwent PFO closure for migraine in the Second Affiliated Hospital Zhejiang University School of Medicine from January 2019 to June 2022,patients were divided into the grade 0 shunt group(n=67),the grade Ⅰ shunt group(n=10),the grade Ⅱ shunt group(n=13)and the grade Ⅲ shunt group(n=16)according to the results of contrast transthoracic echocardiography(cTTE)at 1 year after PFO closure.The incidence of postoperative migraine attacks among different groups of patients were compared.The risk factors of residual shunt after PFO closure were explored. Results:The mean age of enrolled 106 patients with migraine was(35.80±11.70)years,of which 83 patients(78.30%)were female.One year after PFO closure,the migraine attack and rating scale were significantly decreased compared to baseline in the grade 0 shunt group,in the grade Ⅰ shunt group and in the grade Ⅱ shunt group(all P<0.05),but not in the grade Ⅲ shunt group(P>0.05).The rate of significant and complete migraine was significantly higher in the grade 0 shunt group(58.21%),in the gradeⅠ shunt group(60.00%),in the grade Ⅱ shunt group(69.23%)as compared to the grade Ⅲ shunt group(18.75%,P=0.02)at one year after PFO.The rate of grade 0 shunt after PFO closure in patients with the microvesicles appearing in≥6 cardiac cycles in resting state before operation was significantly lower than in patients with the microvesicles appearing within 6 cardiac cycles and no microvesicles in resting state(24.00%vs.83.87%vs.70.00%,P=0.04).Logistic multivariate regression analysis showed that patients with microvesicles appearing beyond 6 cardiac cycles in resting state were more likely to have residual shunts in postoperative cTTE compared to the patients with negative cTTE and microvesicles appearing within 6 cardiac cycles in the cTTE in resting state before operation(OR=0.06,95%CI:0.02-0.23,P<0.01;OR=0.014,95%CI:0.05-0.41,P<0.01). Conclusions:Migraine patients who underwent PFO closure and with grade 0 to grade Ⅱ residual shunt at one year after PFO are most likely to have significant remission of migraine,while the incidence of migraine remission is low in patients with grade Ⅲresidual shunt.The incidence of residual shunt after PFO closure is higher in patients with the microvesicles appearing in 6 cardiac cycles in resting state in the cTTE before operation than in patients with the microvesicles appearing within 6 cardiac cycles and no microvesicles.