Brief communication

Transient ischemic attacks after long-term clamshell occluder implantation for closure of atrial septal defect☆

In this study, we tested 3 techniques of atrial septal defect closure under real-time 3-dimensional echocardiography guidance in a swine model.

The operations were conducted under the sole guidance of a modified real-time 3-dimensional echocardiography guidance system with a ×4 matrix transducer (Sonos 7500, Philips Medical Systems, Andover, Mass). Eighteen swine were anesthetized, and after median sternotomy, the echo probe was applied directly to the surface of the right atrium. To create an atrial septal defect, balloon atrial septostomy and atrial septal defect enlargement were performed. Subsequently, 3 different techniques of atrial septal defect closure were attempted: group I, direct suture closure; group II, closure of the atrial septal defect using the Amplatzer device (AGA Medical Corp, Golden Valley, Minn); and group III, patch closure of the atrial septal defect (n = 6 each).

Real-time 3-dimensional echocardiography guidance provided sufficient spatial resolution and a satisfactory frame rate to provide a “virtual surgeon’s view” of the relevant anatomy during the entire procedure. All atrial septal defects were enlarged, and the mean final size was 8.5 ± 1.8 mm. Atrial septal defect closure was successfully accomplished with all the 3 surgical techniques examined. In groups I and III, the needles (1-3 sutures) and staples (6-12 staples) penetrated the tissue and patch material consistently, whereas in group III, the Amplatzer atrial septal defect device was easily deployed. There was no incident device/staple embolization or air introduction. Neither intraoperative 2-dimensional color Doppler echocardiography nor postmortem macro-evaluation revealed any residual shunts.

Beating heart atrial septal defect closure under real-time 3-dimensional echocardiographic guidance is feasible and, unlike catheter-based devices, applicable for any type of secundum atrial septal defect.

The most critical issues in non-surgical closure of secundum atrial septal defects are device embolization, residual interatrial shunts, cardiac perforation, and patient selection criteria. This report reviews a three-center experience using the recently developed `Das Angel Wings ASD-occluder'. Between February 1996 and January 1997, 44 children underwent catheterization for closure of secundum atrial septal defects (ASD). The characteristics of the defects were evaluated by transesophageal echocardiography (TEE) and intracardiac balloon catheter sizing. With guidance from TEE and fluoroscopy, the self-centering double umbrella was introduced and deployed by transvenous approach in patients with defects ≤20 mm in diameter. The size of the device used was 1.5 times the size of the defect. Implantation was attempted in 26 patients with a balloon-stretched defect diameter of 11.0–19.5 mm, and it was successful in 23 of them. Eighteen patients were excluded because of one of several limiting criteria: additional cardiac defects in three patients, multiple interatrial fenestrations in four; an unsuitable size of the defect in relationship to atrial chamber dimensions in six; a defect size >20 mm in four; and an inadequate inferior septal rim in one. In three of the 23 patients with implantation, the device was removed surgically after suboptimal placement. After a 3-month follow-up, no device embolization was seen and only one patient had a significant residual interatrial shunt. Surgical removal of the device was necessary in one patient who had a late cardiac perforation with hemopericardium and in another patient with a persistently distorted device. In selected patients, transcatheter closure of secundum atrial septal defects is a feasible alternative to surgical correction. Transesophageal echocardiography is useful in identifying suitable defects with a high probability for successful device closure. The self-centering feature of this ASD-Occluder should diminish the risks of embolization of the device, enhance its transvenous implantation, and result in higher efficacy.

Our findings show that transcatheter ASD occlusion with the Clamshell device is safe and reasonably effective, and compares favorably with surgical ASD closure in patients with small to moderate isolated secundum ASDs.

Various devices for transcatheter ASD closure are undergoing clinical trials. Each new device claims advantages in terms of safety and efficacy over earlier devices. We report three cases in which a new investigational device—the Das angel wings—failed. Emergency operations were necessary for device retrieval and defect closure. The possible mechanisms of the event and the options in management are discussed with a review of literature on all devices. (J Thorac Cardiovasc Surg 1996;112:21-6)