Residual Inferior Atrial Septal Defect After
Surgical Repair: Closure Under Intracardiac Echocardiographic Guidance

Case Description. A 41-year-old woman was admitted with the diagnosis of atrial flutter/fibrillation of two days for cardioversion. Her past medical history was remarkable for two operations to repair a secundum atrial septal defect (ASD) at the age of 9 years (initial operation) and 29 years (for residual shunt with significant symptoms); both operations were performed elsewhere and the operative notes were not available to us. Two years prior to this admission, she sustained a transient ischemic attack (TIA) with weakness in her right side and speech impairment. At that time, she underwent complete evaluation of the TIA including a transesophageal echocardiographic examination (TEE) which revealed no anatomical abnormalities and no evidence of a residual ASD. However, a contrast bubble study indicated the presence of right-to-left shunt. The remainder of the work-up was unremarkable. She recovered completely after four hours. She was sent home on Plavix 75 mg per day. She had been doing well until three days prior to this admission when she felt her heart racing. In the emergency room, she was noted to have atrial flutter/fibrillation. Prior to cardioversion, she underwent TEE examination to rule out thrombus formation. The TEE revealed no evidence of thrombus and there was no anatomical evidence of any residual defects (Figures 1A, 1B, 1D, and 1F). However, a contrast bubble study was strongly positive for right-to-left shunt within the first cardiac cycle (Figures 1C and 1E). She was successfully cardioverted to normal sinus rhythm. Due to the presence of the right-to-left shunt, it was decided to take her to the catheterization laboratory for the possibility of finding and closing a very small residual defect using a device. Patient management. Under local anesthesia, the right femoral vein was cannulated using two separate 11 and 9 French (Fr) sheaths. The 11 Fr sheath was for introduction of the AcuNav® catheter for intracardiac echocardiographic evaluation (ICE) (Acuson Corporation, Mountain View, California) and the 9 Fr for hemodynamic evaluation and device closure. Oxygen saturation data revealed the superior vena cava to be 63%, right atrium 67%, left atrium 91% and the right pulmonary artery 71%. Her right heart pressures were normal. ICE catheter was positioned in the inferior vena cava-right atrial junction. Images obtained revealed the presence of a 13.5 mm defect located in the inferior-posterior part of the atrial septum with a 3–4 mm rim of tissue between the defect and the coronary sinus (Figure 2A). Color Doppler echocardiography and contrast bubble study demonstrated significant right-to-left shunt (Figures 2B and 2C). Balloon sizing of the defect using 34 mm sizing balloon (AGA Medical Corporation, Golden Valley, Minnesota) indicated the stretched diameter to be 16.5 mm. Therefore, an 18 mm Amplatzer® Septal Occluder (AGA Medical Corporation) was loaded and inserted via the 9 Fr sheath. The left atrial disk was deployed in the left atrium (Figure 2D) and the remainder of the device was deployed across the defect and the right atrium. After ensuring good device position and no interference with the coronary sinus flow, the device was released. Repeat color Doppler and contrast study were negative for right-to-left shunt (Figures 2E and 2F) and no interference with coronary sinus blood flow. Catheters were removed and hemostasis was achieved by direct compression. The fluoroscopy time was 8.9 minutes and the total procedure time was 67 minutes. The following day, the patient underwent repeat transthoracic echocardiography with color Doppler and contrast bubble study. Both demonstrated good device position and no evidence of any shunt. The patient was discharged home on coumadin for three months. How Would You Manage This Case? P. Syamasundar Rao, MD Professor of Pediatrics Division of Pediatric Cardiology Saint Louis University School of Medicine Cardinal Glennon Children’s Hospital St. Louis, Missouri The preceding report describes transcatheter closure of a residual post-surgical atrial septal defect (ASD) which was the presumed site for paradoxical embolism, causing transient ischemic attack (TIA). Although the ASD was not visualized by two prior transesophageal echocardiographic (TEE) studies, the authors successfully imaged the defect using intracardiac echocardiographic examination (ICE). They measured the balloon stretched diameter of the defect with a PTA-OS balloon catheter and closed the residual defect successfully with an 18 mm Amplatzer Septal Occluder. The authors are to be congratulated for their success in delineating the defect which could not be done by two prior TEEs. The second problem, i.e., atrial flutter/fibrillation, was successfully cardioverted to normal sinus rhythm. I will address the issue of closure of the ASD only. Because of the fact that none of the ASD closing devices are available for routine clinical use, the method of closure and the device used will largely be dependent upon what is available at a given institution during a given time. Because of our participation in the FDA-approved clinical trials with IDE (investigational device exemption), we employ the buttoned device1,2 for such transcatheter ASD occlusions.3 We currently use a centering-on-demand (COD) device (Custom Medical Devices, Amarillo, Texas), which is a fourth-generation, double-buttoned device with centering mechanism.4,5 Our approach to this particular patient is as follows: we initially perform a percutaneous right heart catheterization under conscious sedation and local anesthesia. Left atrial angiography is performed with the tip of the angiographic catheter positioned at the right upper pulmonary vein/left atrial junction in a 30° left anterior oblique and 30° cranial view. This would have defined the anatomy of the atrial defect, just as ICE is described above. Following demonstration of the atrial defect, we measure the stretched diameter of the ASD with a venous occlusion balloon (Meditech, Natick, Massachusetts) as described elsewhere.6–8 More recently, we have been using PTA-OS balloon catheters (NuMed Inc., Hopkinton, New York),9 which is a static method, measuring the waist of the balloon produced by the ASD rims, both by cine fluoroscopy and echocardiography. The diagonal size of the device selected should be approximately 1.8 times the stretched ASD diameter. A 10 French blue Cook sheath (Cook, Bloomington, Indiana) with a radiopaque marker at the tip is positioned in the left atrium over a previously placed guidewire in the left upper pulmonary vein. Based on balloon-stretched diameter of 16.5 mm, a 30 or 35 mm (diagonal length) COD buttoned device is selected for implantation. The device is tested for its functionality and immersed in saline solution to eliminate air bubbles from the polyurethane foam component of the device. The occluder is folded and introduced into a short sheath piece supplied with the device. The loaded sheath is introduced via the valve mechanism of the 10 Fr long delivery sheath, which is clamped proximally. The system is flushed to eliminate any air bubbles and the sheath unclamped. The occluder is advanced with the pusher catheter and delivered into the left atrium. The centering mechanism is folded in the left atrium and the device positioned over the atrial septum, covering the ASD. The pusher catheter is removed and the sheath clamped. A 25 or 30 mm square-shaped occluder component of an inverted buttoned device10 is loaded over the delivery wire, deposited into the long sheath in a manner similar to that described for the occluder, and delivered into the right atrium. Both the occluders are buttoned across the ASD. The counter occluder of the COD device is then delivered into the right atrium and buttoned. The delivery wire is cut and removed followed by the removal of the nylon thread, thus disconnecting (releasing) the device. During both the above maneuvers, the tip of the long sheath is gently pressed against the buttoned device to prevent applying excessive force on the device, thereby preventing inadvertent dislodgement of the device. Contrast echocardiography by injecting agitated saline via the long sheath is performed prior to removal of the sheath. Three doses of antibiotics (Ancef 1gm) and heparin during the procedure are routinely used. On the following day, chest x-ray and transthoracic two-dimensional, color Doppler and contrast echocardiography are performed. Coumadin is restarted and continued for 6 to 12 weeks. In summary, the use of ICE to document the ASD appears attractive, although the defect could have been demonstrated by angiography. Balloon sizing of the device is generally required for selection of the size of the device. There are a number of ASD closure devices under clinical trials presently11 and most of them are suitable for closure of ASD in this patient. Because of the lack of availability of all devices to all cardiologists, the selection of the type of device, at this time, is largely dependent upon what is available at a given institution. Whether the available device is suitable for a given defect has to be determined by the cardiologist performing the procedure. In the present case, the hybrid buttoned device that we routinely use at our institution is suitable for closure of her residual ASD. John W. M. Moore, MD Director, The Heart Center for Children St. Christopher’s Hospital for Children Professor of Pediatrics MCP Hahnemann University School of Medicine Philadelphia, Pennsylvania Dr. Hijazi presents an interesting case of a residual inferior atrial septal defect (ASD) after two open-heart surgeries, and an innovative and successful treatment using an Amplatzer Septal Occluder (ASO) guided by Intracardiac Echocardiography (ICE). I have several questions regarding details of this case and procedure, which would be of interest to operators dealing with similar issues. First, are transthoracic and/or transesophageal echocardiography truly incapable of diagnosis and definitive evaluation of inferior ASD, and is this ASD the same as an “inferior sinosus venosus” defect? Second, what are the implications of partial coverage of the coronary sinus by the right-sided disc (suggested by the 3 to 4 mm distance from the rim of the defect to the coronary sinus)? Third, are there any special considerations for use of an ASO in the presence of atrial fibrillation/flutter? Finally, what anticoagulation regime is recommended, and how should it be monitored? Nevertheless, this patient with two prior unsuccessful open-heart surgeries clearly benefited from the approach taken by Dr. Hijazi and his colleagues. I would like to congratulate them on this extension of the indications for the ASO, i.e., closure of the inferior ASD, and on the use of ICE in a situation in which other types of echocardiography may have limitations. Satinder K. Sandhu, MD Louisiana State University Medical Center New Orleans, Louisiana This paper is a case report of residual atrial septal defect and its closure by the transcatheter technique. I agree with the transcatheter approach presented by the authors. This paper makes an important point that in the presence of a right-to-left shunt transesophageal echocardiogram may not always reliably define the defect. This paper illustrates that intracardiac echocardiography may be much more sensitive than transesophageal echocardiography in defining the residual atrial septal defect. The use of intracardiac echocardiography would also allow the procedure to be done without transesophageal echocardiography, thereby eliminating the need for intubation. Intracardiac echocardiography appears to more accurately define the relationship of the device with the surrounding heart structures such as the coronary sinus. My only concern is the duration of anticoagulation in this subgroup of patients with atrial fibrillation and/or flutter. This patient was sent home on coumadin for three months, which is a reasonable duration for endothelilization of the device. However, there are no studies currently available to demonstrate the duration of time for which anticoagulation is needed in patients with atrial arrhythmias who undergo an atrial septal defect device placement.

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