Double-disk Device Research Articles

Initial clinical results with the Amplatzer septal occluder--a self-centering double disc for occlusion of atrial septal defects

In recent years many different systems for transcatheter closure of an atrial septal defect (ASD) have been developed and tested. However, all systems presently available have some special disadvantages. The recently introduced Amplatzer Septal Occluder (ASO), though, appears promising. It is a self-expanding and self-centering double disc made from a Nitinol mesh, which is tightly woven to give mechanical strength. Both discs are separated by a connecting cylindrical portion. Its diameter may be chosen, so that it corresponds to that of the ASD. Discs of polyester patches are sewn into the retention discs as well as into the cylindrical portion of the device in order to augment thrombogenicity. After measuring the diameter of the ASD with a balloon, an appropriate ASO is selected and advanced into the left atrium through a 7 or 8 French sheath. Then the distal disc and part of the connecting cylindrical portion is developed in the left atrium and pulled against the atrial septum, so that the cylindrical portion is occluding the ASD. Thereafter, proximal disc is deployed and the delivery cable disconnected. As long as the cable is connected to the device repositioning is easily achieved by pulling the device back into the sheath. Within a time period of 4 months in 29 out of 31 patients (median age: 12.1 years, median weight: 45.0 kg) complete closure of the ASD with a mean diameter of 11.0 mm (6-20 mm) was achieved without complications, the average fluoroscopy time being 8.3 min (2.9-21.5 min). Mean Qp:Qs was 1.5 (0.9-2.2). During a mean follow-up period of 2.1 months post implantation fixed seating of the ASO without residual shunt, arrhythmias, thrombembolic events and impairment of A-V valves was observed in all patients. The Amplatzer septal occluder allows quick, safe, and complete closure of atrial septal defects without complications if one adheres to strict implantation criteria. For a final judgement, however, long-term follow-up studies are necessary.

Echocardiographic guidance during placement of the buttoned double-disk device for atrial septal defect closure.

The usefulness of two-dimensional and Doppler echocardiography during buttoned double-disk device closure of an atrial septal defect was evaluated in 20 consecutive patients at the time of interventional catheterization. Transesophageal echocardiography was used in 11 patients (ages 5 to 62 years, weights 20 to 91 kg). Because of the size of the available transesophageal echo probe, transthoracic echocardiography was used in the remaining 9 patients (ages 4 to 5.5 years, weights 14 to 21 kg). In the transesophageal echo group, 1 patient was found to have no atrial septal defect despite a previous diagnosis by transthoracic echocardiography, 3 patients had atrial septal defects too large for closure despite attempts in 2, and 7 patients had transesophageal echo guided device placement. All of these 7 patients had small residual shunts by color Doppler, 2 had unusual arm positions, and 2 had surgical removal of the device due to embolization to the pulmonary artery in 1 and failure to obtain close approximation of the occluder and counteroccluder in 1. In the transthoracic echo group, 2 patients had atrial septal defects too large for closure, 1 patient had no femoral venous access, and 6 patients had transthoracic echo guided device placement. All of these 6 patients had small residual shunts by color Doppler and 3 of the 6 had unusual arm positions. For atrial septal defect sizing, transesophageal echo measurements correlated with catheter balloon size more closely than did transthoracic echo measurements (r 2 = 0.97 vs 0.86).(ABSTRACT TRUNCATED AT 250 WORDS)

Echocardiographic follow-up of percutaneous closure of the arterial duct in infants

SummarySince February 1990, we have attempted nonsurgical occlusion of persistent patency of the arterial duct using the Rashkind double-disk occluding device, of either 12 or 17 mm diameter. Results are presented from 31 patients (23 female and eight male, ages 15 months to 16 years). M-Mode, cross-sectional, Doppler and color Doppler echocardiographic studies were made prior to closure, in the following 24 hours, and six months later. Left ventricular diastolic dimension and shortening fraction, systolic intervals, and left atrium/aortic ratio were evaluated by M-Mode echo. We examined carefully the location of the device relative to the left pulmonary artery and descending aorta, also checking for disturbed flows and residual shunts. These studies showed a clear tendency for the left ventricular diameter to decrease, and revealed a significant normalization of the left atrium/aortic ratio. Successful closure of the duct was achieved in 27 cases. Follow-up studies six months later showed residual shunting in four cases. In one patient, a second device was implanted with an excellent result. At the immediate follow-up, turbulences were noted in the area of the device (nine cases) and in the left pulmonary artery (seven cases). Distortion of the anatomic orientation of the left pulmonary artery was observed in three cases in which we discovered 20 mm Hg systolic gradients. In our opinion, echocardiography is the best technique with which to follow-up these patients. The high sensitivity of color Doppler echocardiography revealed minimal distortion of the left pulmonary artery, probably generated by regional anatomic adjustment to the insertion of the device.

Transcatheter Atrial Septal Defect Occlusion Devices: Normal Radiographic Appearances and Complications

Three transcatheter atrial septal defect (ASD) occlusion devices have been used in clinical trials during the past decade: the Rashkind ASD occluder, the Lock Clamshell occluder, and the buttoned double-disk device. The normal radiographic appearance of these three devices and radiographic findings in complications are presented. Of 12 transcatheter ASD occlusions performed, the buttoned double-disk device was used in eight patients, the Rashkind ASD occluder in three, and the Lock Clamshell occluder in one. Complications included both improper placement and partial dislodgment of the Rashkind ASD occluder device (n = 2), fracture of a metal arm of the Lock Clamshell device (n = 1), and detachment of the buttoned double-disk device with embolization into the right pulmonary artery (n = 1). Knowledge of the normal radiographic appearance of ASD occlusion devices and the findings in various complications will be necessary for radiologists as transcatheter ASD closure becomes more commonplace. Chest radiography is the primary method of detecting short- and long-term complications in patients following transcatheter ASD closure.

Role of “buttoned” double-disc device in the management of atrial septal defects

Sixteen patients seen over a 9-month period ending in August 1990 were offered transcatheter closure of their ASD with a custom-made “buttoned” double-disc device. The study was approved by the Institutional Review Board and informed consent was obtained in each case. The device consists of an occluder, a counteroccluder, and a loading wire and is delivered to the ASD site via an 8F sheath. Parents of two children elected surgical closure. In five children the stretched diameter of the ASD was too large (>20 mm) and transcatheter closure was not attempted. These seven children underwent elective surgical closure without incident. In one child the defect measured 5 mm and the Qp:Qs was 1.4:1 and therefore ASD closure was not recommended. In the remaining eight children transcatheter closure was attempted. In two of the children the occluder pulled through the ASD and was successfully retrieved and the children later underwent uneventful elective surgical closure. The device was implanted across the ASD in six children. In one child the device dislodged from the ASD site within minutes after implantation and the child was sent to emergency surgery, where the device was removed and the ASD was closed. In the remaining five patients, aged 7 months to 45 years (weight 3.6 to 50 kg), with a Qp:Qs range of 1.3 to 2.3 and a stretched diameter of 10 to 19 mm, the ASD closure was successful with 25 to 40 mm size devices. Repeat echo-Doppler studies 2 weeks and 3 months after the procedure in all patients and 6 months later in two children did not reveal any residual shunt.It is concluded that (1) the custom-made “buttoned” double-disc device can be implanted across the ASD safely and effectively via an 8F sheath, thus making transcatheter ASD closure feasible even in very young infants; (2) measurement of stretched diameter of the ASD in the catheterization laboratory is a useful guide for selection of an appropriate-sized device; and (3) additional clinical trials are warranted to confirm the efficacy and safety of the device.

Transcatheter closure of patent ductus arteriosus with buttoned device: First successful clinical application in a child

Several devices are available for transcatheter closure of PDA. Most of the available devices either require complicated intracardiac maneuvering or need a large-sized sheath for implantation of the device. A recently described “buttoned” device developed by Sideris et al. that can be delivered across the ductus via a 7F sheath had undergone successful trials in animal models. Because of the ease of device implantation and the requirement for a smaller-sized sheath for delivery than that used with other devices, we have used this custom-made double-disc device in a 5-year-old child and have shown successful closure of the ductus by angiography and by color Doppler studies. Further clinical trials with this device seem warranted.

Role of ‘buttoned’ double disk device in the management of atrial septal defects

Role of ‘buttoned’ double disk device in the management of atrial septal defects

Transvenous atrial septal defect occlusion in piglets with a "buttoned" double-disk device.

The feasibility and safety of transvenous closure of atrial septal defects by a new device was tested in 20 piglets, in which atrial septal defects were created by foramen ovale dilatation with angioplasty balloons. The device was small enough to be introduced in a 7F or 8F sheath, and it measured 20-25 mm. It has no hooks and consists of a foam occluder from the left atrium and a counter-occluder from the right atrium, buttoned independently. The animals were observed by angiography and color flow mapping, and they were electively killed at various intervals up to 2 months after occlusion. The device was not thrombogenic and had endothelialized by 2-3 weeks. All atrial defects were found to be completely occluded. Complications occurred only with the first three prototype devices, including counter-occluder detachment, right atrial perforation, and need for double occlusion and pulmonary artery embolization. No such complications occurred in the last 17 experiments because of modifications of the device and operator experience. These observations showed the feasibility of occlusion of moderate-size atrial septal defects in piglets by a new device introduced through a small sheath. The method appears promising for potential human application.