Acute animal studies of the STARFlex system: a new self-centering cardioSEAL septal occluder

[Interventional closure of atrial septal defects, patent oval foramen and ventricular septal defects]

Percutaneous transcatheter closure techniques and devices for congenital intracardiac shunts have considerably improved; therefore, catheter closure is now the treatment of choice for atrial septal defects (ASD). This is technically feasible in more than 80% of patients with a secundum ASD and the success rate is higher than 99%. General anesthesia is as a rule unnecessary and the hospital stay is very short. A patent oval foramen (POF) is a potential cause of cryptogenic stroke and peripheral embolisms. The catheter occlusion has many advantages in comparison to lifelong anticoagulation therapy and for some patients it is the only therapeutic option. Randomized trials have shown that interventional closure leads to results which are comparable to drug therapy and for some occlusion systems even evidence of significant advantages compared to drug therapy was found. Even ventricular septal defects (VSD), including perimembraneous and post-myocardial infarction VSDs can be closed by catheter techniques with a high success rate.

Transcatheter Device Closure of Congenital and Postoperative Residual Ventricular Septal Defects

Background— Our purpose was to describe a 13-year experience with patients undergoing transcatheter device closure of unrepaired congenital or postoperative residual ventricular septal defects (VSDs).

Methods and Results— Since 1989, 170 patients (median age, 3.9 years) have undergone catheterization for closure of 1 or more congenital (n=92) or postoperative (n=78) residual VSDs using successive generations of STARFlex-type devices. Outcomes included echocardiographic assessment of residual flow and device position, assessment of VSD shunt/severity, and adverse events. Among 168 patients in whom device implantation was performed, between 1 and 7 devices were placed per patient (median, 1), with multiple devices placed in 40%. There was a significant decrease in left-to-right shunting after device implantation ( P <0.001) and significant improvement in VSD size/severity, and device position proved stable. Of 332 adverse events, 39 were related to the device and 261 were related to the catheterization; all but 5 occurred in the periprocedural period. At a median follow-up of 24 months (0 to 154 months), 14 patients had died and 18 had device(s) explanted.

Conclusions— Congenital and postoperative VSD closure using STARFlex-type devices resulted in stable improvement in clinical status and decreased interventricular shunting. Although periprocedural events occurred frequently, late events caused by the device were rare. Transcatheter device closure is an effective management option for patients with complex muscular VSDs that are difficult to approach surgically and for postoperative residual VSDs.

Incidence and clinical course of thrombus formation on atrial septal defect and patient foramen ovale closure devices in 1,000 consecutive patients

OBJECTIVES

The purpose of this study was to investigate the incidence, morphology, and clinical course of thrombus formation after catheter closure of intra-atrial shunts.

BACKGROUND

Post-procedure detailed information about thrombotic material on different devices for transcatheter closure is missing.

METHOD

A total of 1,000 consecutive patients were investigated after patent foramen ovale (PFO) (n = 593) or atrial septal defect (ASD) (n = 407) closure. Transesophageal echocardiography (TEE) was scheduled after four weeks and six months. Additional TEEs were performed as clinically indicated.

RESULTS

Thrombus formation in the left atrium (n = 11), right atrium (n = 6), or both (n = 3) was found in 5 of the 407 (1.2%) ASD patients and in 15 of the 593 (2.5%) PFO patients (p = NS). The thrombus was diagnosed in 14 of 20 patients after four weeks and in 6 of 20 patients later on. The incidence was: 7.1% in the CardioSEAL device (NMT Medical, Boston, Massachusetts); 5.7% in the StarFLEX device (NMT Medical); 6.6% in the PFO-Star device (Applied Biometrics Inc., Burnsville, Minnesota); 3.6% in the ASDOS device (Dr. Ing, Osypka Corp., Grenzach-Wyhlen, Germany); 0.8% in the Helex device (W.L. Gore and Associates, Flagstaff, Arizona); and 0% in the Amplatzer device (AGA Medical Corp., Golden Valley, Minnesota). The difference between the Amplatzer device on one hand and the CardioSEAL device, the StarFLEX device, and the PFO-Star device on the other hand was significant (p < 0.05). A pre-thrombotic disorder as a possible cause of the thrombus was found in two PFO patients. Post-procedure atrial fibrillation (n = 4) and persistent atrial septal aneurysm (n = 4) had been found as significant predictors for thrombus formation (p < 0.05). In 17 of the 20 patients, the thrombus resolved under anticoagulation therapy with heparin or warfarin. In three patients, the thrombus was removed surgically.

CONCLUSIONS

The incidence of thrombus formation on closure devices is low. The thrombus usually resolves under anticoagulation therapy.

Healing response to the Clamshell device for closure of intracardiac defects in humans

The healing response to intracardiac devices in humans is largely unknown. During regulatory trials using the Clamshell device in over 800 patients, attempts were made to perform histopathological evaluation of all explanted devices. We reviewed all those with complete histopathological examination (n = 12) from Fontan baffles (n = 4), ventricular septal defects (n = 2), and atrial septal defects (ASD; n = 6), explanted at 2.7 months to 3.6 years (median, 1.6 years), at autopsy (n = 1) or surgery (n = 11), performed for residual defects (n = 5), atrial masses (n = 3), or Fontan revision (n = 3). All but one were nearly (n = 3) or completely (n = 8) covered by pseudointima, composed of fibroelastic tissue, predominantly collagen, with focal foreign body reaction in contact with fabric, without acute inflammation or infection. Atrial masses of granulation tissue were present in three cases (ASD), opposite to protruding fractured arms. No associations were identified between coverage and closure status, position, arm fractures, or implant period. In conclusion, the healing response to transcatheter Clamshell implantation in humans is characterized by a relatively rapid development of a nonthrombotic pseudointima composed of fibroelastic tissue with minimal foreign body reaction. Cathet Cardiovasc Intervent 2001;54:101-111.

Steerable control of the eustachian valve during transcatheter closure of secundum atrial septal defects

Over the past decade there has been increased use of transcatheter devices for closure of secundum atrial septal defects. The presence of a large eustachian valve complicating transcatheter closure has not been described. We describe four patients with prominent eustachian valves, in three of whom we employed a simple technique to obtain control of the eustachian valve during device placement using transesophageal echo guidance.

Recommendations of the British Paediatric Cardiac Association for therapeutic cardiac catheterisation in congenital cardiac disease

The aims of these recommendations are to improve the outcome for patients after, and to provide acceptable standards of practice of therapeutic cardiac catheterisation performed to treat congenital cardiac disease. The scope of the recommendations includes all interventional procedures, recognising that for some congenital malformations, surgical treatment is equally as effective as, or occasionally preferable to, interventional treatment. The limitations of the recommendations are that, at present, no data are available which compare the results of interventional treatment with surgery, and certainly none which evaluate the numbers and types of procedures that need to be performed for the maintenance of skills. Thus, there is a recognised need to collect comprehensive data with which these recommendations could be reviewed in the future, and re-written as evidence-based guidelines. Such a review will have to take into account the methods of collection of data, their effectiveness, and the latest developments in technology. The present recommendations should, therefore, be considered as consensus statements, and as describing accepted practice, which could be used as a basis for ensuring and improving the quality of future care.

Interventional catheterization

Several investigations have been performed to evaluate the mid-term results of coil embolization for patent ductus arteriosus. Excellent results were obtained with coils if the minimum diameter of the ductus was less than 4 mm. Balloon dilation of native coarctation and recoarctation may be associated with complications such as aneurysm formation. Stent placement may solve some of the problems of balloon dilation, but the stents currently available are not perfect. Results of transcatheter closure of atrial septal defect using new devices have been were reported. The self-expanding nitinol double-disk device (Amplatzer septal occluder) (AGA Medical Corporation, Golden Valley, Minnesota) is becoming popular because it is easy to implant, is easy to retrieve before its release, can occlude a relatively large defect, and has a low rate of residual leak. Although the immediate results with this device were excellent, surgical closure is still the standard treatment and we need to see the long-term results of transcatheter closure.