Transcatheter closure of atrial septal defect: are we there yet?

Surgical closure of ostium secundum atrial septal defects (ASDs) can be performed successfully with low (,1%) mortality. However, the morbidity associated with general anesthesia, thoracotomy, cardiopulmonary bypass, postoperative monitoring in the intensive care unit and several days of hospital stay is considerable. The expense associated with this morbidity, operative scar and psychologic trauma to the patient and parents are additional disadvantages of surgical treatment. For these reasons, several groups of cardiologists, for the past two and one-half decades, have been investigating transcatheter methods to close the ASDs. The pioneering works of King and colleagues (1–3) and Rashkind and colleagues (4–6) have paved the way in these efforts. King designed paired, opposed, Dacron-covered, stainless steel umbrellas collapsed into a capsule attached to the tip of the catheter that were implanted across the atrial septum through a 23F sheath. Because of the large delivery sheath, requiring cutdown, and complexity of the procedure, King neither continued the investigation nor did other cardiologists adopt this method. Rashkind designed a single, foam-covered umbrella with miniature hooks with an elaborate centering mechanism and applied it to animal models and human subjects (4–6). The device and delivery system, although less bulky than King’s device, still required a 16F sheath for device implantation. Because of the difficulties associated with implantation of the hooked device, Rashkind introduced a double-disk system, similar to his patent ductus arteriosus occluding device (6). This double-disk device was later modified by Lock et al. (7); this device is without hooks but with a bend in the arms of the device and uses spring tension to allow arms of the device to fold against each other and has been named the Clamshell device. This device requires an 11F sheath for implantation. Although the initial clinical trials with the device were encouraging, development of fractures of the arms of the device and embolization (8,9) forced the investigators and the Food and Drug Administration to withdraw the device (in 1991) from further clinical trials. A buttoned double-disk device that can be implanted through an 8F sheath was developed by Sideris et al. (10). Single institutional (11–15) and multi-institutional (16–18) clinical trials began. At the time of last review (19), nearly 800 devices had been implanted and, at present . 1,000 ASDs have been closed with the buttoned device (Sideris EB, personal communication, November 1997). Over the past few years, a large variety of other devices have suddenly emerged. These include the monodisk device of Pavc̆nick et al. (20), Das-Angel Wing self-centering device (21), the atrial septal defect occluding system (ASDOS) (22,23), the Amplatz septal occluder (24) and the redesigned Clamshell (the CardioSeal device) (25). Clinical trials within or outside the United States have just begun with the majority of these devices. In this issue of the Journal, Thanopoulos et al. (26) present preliminary results of their experience with the Amplatzer septal occluder. The device consists of two self-expandable round disks connected to each other with a 4-mm wide waist (Fig. 1 in Thanopoulos et al. [26]), made of 0.004to 0.005-in. Nitinol wire mesh and filled with Dacron fabric (24,26). Eighteen of the 22 patients evaluated met echocardiographic criteria for device closure, and of these 18 patients with intent to close, 16 (89%) underwent successful device implantation; in the remaining 2, closure was not attempted because of the large, stretched diameter of the ASD. Misplacement of the device occurred in one patient (6%), but the disks of the device were withdrawn into the delivery sheath and device redeployed successfully. Complete occlusion of the defect by angiography and color Doppler echocardiography was demonstrated in 13 patients (81%). The follow-up duration was short, 1 to 3 months. Residual shunt was present in only one patient (6%) at 3-month follow-up. As I began writing this editorial in late November 1997, I was under the impression that the report by Thonopoulos et al. (26) was the first clinical report, but before I completed this editorial, my attention was drawn to the report by Masura et al. (27) in the December 1997 issue of Catheterization and Cardiovascular Diagnosis. They also report their preliminary experience with the Amplatzer. Their results in 30 patients are similar to those reported by Thanopoulos et al. (26). The advantages of the Amplatzer device appear to be small delivery sheath, ease with which the method of implantation is learned and the ability to retrieve and reposition the device (without damaging it) before release. However, the high success rate may, in part, be related to relatively small-sized defects that were occluded. It remains to be seen whether such results are maintained when more variable-sized defects are closed and when the method is applied to larger groups of patients than are presented the report by Thanopoulos et al. (26). The authors state that the waist of the device, stenting the defect, is the major support for device retention, but I suspect that the disks on either side of the septum also play a role in *Editorials published in Journal of the American College of Cardiology reflect the views of the authors and do not necessarily represent the views of JACC or the American College of Cardiology. From the Department of Pediatrics, Division of Pediatric Cardiology, Saint Louis University School of Medicine/Cardinal Glennon Children’s Hospital, Saint Louis, Missouri. Address for correspondence: Dr. P. Syamasundar Rao, Division of Pediatric Cardiology, Saint Louis University School of Medicine, 1465 South Grand Boulevard, Saint Louis, Missouri 63104. E-mail: raops@slu.edu. JACC Vol. 31, No. 5 April 1998:1117–9 1117