Our study was approved by the ethic committee of the First Affiliated Hospital of Wenzhou Medical University. In this study, we retrospectively analyzed 140 patients who underwent PFO closure or right cardiac catheterization in the Department of Cardiology of The First Affiliated Hospital of Wenzhou Medical University from August, 2018 to December, 2020. 97 cases successfully underwent PFO closure and 43 cases did not have PFO based on the results of the right cardiac catheterization; 37 cases of cerebral infarction and 103 cases of migraine; 84 cases underwent cTTE, 130 cases underwent TEE and 114 cases underwent cTCD. All patients were examined by routine blood tests, Holter, head CT or magnetic resonance, vascular ultrasound, etc. after admission.
The definition and grading of cTTE
The standard apical four-chamber view was taken by GE vividE95 Doppler echocardiography. After intravenous injection of activated saline, the microbubble signal in the left ventricular system was defined as positive within 3-5 cardiac cycles after the right heart system was filled with microbubble signal. Then the activated saline was injected intravenously again after Valsalva maneuver. Grading standard : grade 0, no microbubble; grade I, mild RLS, 1–10 microbubbles; grade II, moderate RLS, 11–30 microbubbles; grade III, massive RLS, >30 microbubbles or the left atrium was almost full of microbubbles (Figure 1).
The definition and grading of cTCD
Elica transcranial Doppler detector with probe frequency of 1.6 MHz was used to monitor the left middle cerebral artery. The number of microbubbles in the middle cerebral artery was observed within 10 seconds after intravenous injection of activated saline. If the microbubble signal was not detected in the resting state, the activated saline was injected intravenously again after Valsalva maneuver. Grading standard : grade 0, no shunt, no microbubble; grade I, mild shunt, 1–10 microbubbles; grade II, moderate shunt, 10–25 microbubbles; grade III, massive shunt, >25 microbubbles.
The clinician inserted the probe through the esophagus and scanned in the direction of 0°- 180° to show the complete atrial septum. In the sections of two atriums and the superior and inferior vena cava of both atriums, we focused on whether there was a gap between the primary secondary septum. Then we measured the internal diameter of the gap and observed whether there was oblique transseptal shunt with Doppler flow echo (Figure 2).
Indications and contraindication of PFO closure
Indications: (1) Stroke of unknown causes or TIA with PFO, had moderate or massive RLS, or relapsed with anticoagulant therapy, or had definite deep venous thrombosis. (2) Intractable or chronic migraine complicated with moderate or massive RLS in PFO. (3) PFO complicated with venous thrombosis or varicose veins / valvular insufficiency of lower extremities, with moderate or massive RLS. (4) High risk PFO, PFO complicated with atrial septal neoplasm, large diameter or resting RLS. (5) The age was from 18 to 60 years old.
Relative indications: (1) PFO with migraine; (2) PFO with high risk factors of venous thrombosis (long-term sitting or lying in bed); (3) PFO with extracranial artery embolism; (4) special occupations with PFO (such as divers, etc.); (5) hypoxia with PFO which was difficult to explain clinically.
Contraindication: (1) cerebral embolism of any cause could be found; (2) could not tolerate antiplatelet or anticoagulant therapy; (3) thrombosis of inferior vena cava or pelvic vein led to complete obstruction, systemic or local infection, septicemia, and intracardiac thrombosis. (4) pregnancy; (5) complicated with pulmonary hypertension or PFO as a special channel; (6) acute stroke in 2 weeks.
The procedure of PFO closure
The PFO occluder made by Shanghai Shape Memory Alloy Co., Ltd. was selected. After femoral vein puncture, we sent the guide wire and 6F right heart catheter to the right atrium under X-ray. Then the guide wire and catheter were sent into the left superior pulmonary vein through the foramen ovale. Next, we replaced guide wire with super stiff wire and sent the sheath into the left atrium. At last, we sent into the PFO occluder and released it after the position was confirmed by X-ray and ultrasound. After operation, aspirin was given orally 100mg once a day for 6 months.
SPSS20.0 software was used for statistical analysis. All measurement data were expressed as mean ± standard deviation, and the differences between groups were analyzed by T test. All counting data were expressed by constituent ratio. The differences between groups were analyzed by Mann-Whitney U test. The sensitivity and specificity of the method were evaluated by ROC curve. P < 0.05 was considered statistically significant.