Transcatheter Closuer Of Atrial Septal Defects And The Influences On Blood Dynamics

Background As so far several interventional methods have been used to closure atrial septal defects(ASD). Transcetheter closure of secundum ASD using the Amplatzer septal occluder(ASO) is one of the most efficient methods. Although some studies indicate that transcetheter closure of ASD have some certain influences on the cardiac chambers and some blood dynamic indices, but lack of the systemic study about the cardiac chambers changing speed. None study have observed the changes of the Doppler blood spectral shape characteristics of pulmonary and artic valve orifices. It is not clear about the safety and reliability of using transthoracic echocardiography (TTE) to guide the ASD intervention procedure using ASO.Objective Present study is to observe the safety and efficacy of transcatheter closure of secundum ASD using the ASO under the guiding of TTE and to observe the influences on blood dynamics. (1) Observe the changes and the changing speeds of cardiac chambers after the intervention. (2) Combination using of electrocardiography and Doppler echocardiography to observe the changes of Doppler blood spectral characteristics at the orifices of mitral valve, aortic valve and pulmonary valve.Methods Total of 24 patients with secundum ASD were included, among them, 10 male, 14 female. Age 5~61years ( average 34.6±16.4 years ). Diameters of ASD 6~30mm(average 19.3 ±6.9mm). TTE and digital subtract angiography (DSA) were usedfor guiding the device closure of ASD. The stretched diameters of ASDs were measured by balloon and then the ASOs 0~4mm greater than stretched diameters were selected. Before the procedure and at follow up of 1 day, 1, 3, 6 and 12 months patients were assessed with color Doppler echo to measure the diameters of cardiac chambers, the systolic pressure of pulmonary artery. The blood spectrals were recorded with pulsed Doppler echo at pulmonary valve orifice (Pv wave), aortic valve orifice (Av wave) and mitral valve orifice (E wave and A wave) respectively. For Pv and Av wave, the R-Pv interval or R-Av interval (from the top of ECG R wave to the onset of spectral), acceleration time (AT), peak velocity (PV), average acceleration (AA), deceleration time (DT) and average deceleration (AD) were measured. For E and A wave, the T-E interval (from the end point of ECG T wave to the onset of E wave), E wave acceleration time (AT-E), deceleration time (DT-E), peak velocity of E wave (PV-E) and A wave (PV-A), E/A ratio were measured.Results (1) 21 ASDs (87.5%) were successfully closed. 3 ASDs failed closed with either large ASD diameters in two cases (38mm, 40mm) or inferior vena cava type ASD in one case. All the 3 ASOs were pulled out safely without complications. The mean procedure time is 76 + 31 minutes (50~180minutes). The mean in hospital time is 8.8 + 4.2 days (4-21 days). When exclude one case with thrombus formation on the device after procedure, the mean in hospital time is 8.1 ±3.0 days (4-14 days). The mean in hospital time after the procedure is 4.7 + 3.7 days (2-18 days). In one case with two nearby ASDs the small ASD was closed naturally lday after the large ASD was closed with ASO. (2) Complications neither common nor serious. In one case, thrombus formation on the device (ASO 40mm) was founded 1 day after the procedure and disappeared 12 days after antiplatelet and anticoagulation treatment. Hypermenorrhea occurred in one 20 years old female treated combined with clopidogrel and aspirin. When clopidogrel withdrawal, the bleeding stopped. Atrial premature beats occurred in two cases after the procedure. Trivial residual shunts immediately after the ASO deployed in 5 cases disappeared 24 hours later. (3) linear correlation analysis showed that there were good correlations between the ASD diameter measured by TTE and stretched diameter (r =0.949; p< 0.0001) or the ASO size (r=0.959; P<0.0001).(4) The diameter of left atrium and the inner diameter of pulmonaryartery had no significant changes after ASD closed. At one month, left ventricular end diastolic diameter (LVEDD) enlarged significantly whereas right atrium area decreased significantly and both were maintained at 12-month follow-up. At one day, right ventricular end diastolic diameter (RVEDD) decreased significantly. This trend kept to 3 months and was maintained at 12-month follow-up. At 6 months, right ventricular end diastolic diameter returned to normal limit generally. (5) At 6-month follow-up, the systolic pulmonary pressure had no significant changes. R-Pv interval prolonged significantly at 24 hours and was maintained later. PV-Pv, AA-Pv, AD-Pv and DT-Pv decreased or shortened at 1 day to 1 month and were maintained respectively whereas AT-Pv had no significant changes. R-Av interval prolonged at 1 day and returned to the level of that before the procedure. At 1 month, AA-Av increased significantly. For DT-Av, There were no differences before and after the procedure whereas it prolonged at 1 month and 6 months compared with that at 24 hours. There were no significant changes for AT-Av, PV-Av, AD-Av, T-E interval, AT-E, PV-E, PV-A and E/A ratio. DT-E decreased at 6 months than that at 3 months.Conclusion (1) The use of ASO is safe and effective in complete closure of secundum ASDs up to a diameter of 40mm in the majority of patients. The smaller the ASD is, the higher the successful rate reached. (2) The diameter of ASD measured with TTE can be used to estimate the stretched diameter and the ASO size needed. (3) TTE can be used to guide the closure of secundum ASDs in adults with ASO safely and effectively. (4) Closure of secundum ASD result in right ventricular end diastolic diameter and right atrium area decrease and the enlarged RVEDD get back normal range generally at 6 months. After the closure procedure, LVEDD decreased, but the decreased speed and extent is not as great as RVEDD. Closure of ASD has no effect on left atrial size and pulmonary artery diameter. (5) Closure of ASD result in decreased right ventricle systolic function compared with that before the procedure. This change can be considered as the regression to normal. (6) After the closure of ASD, left ventricle systolic function increased in some certain extent but this change is not as markedly as that of right ventricle systolic function. (7) Closure of ASD has no effect on left ventricle diastolic function. (8)...