Transcatheter closure of surgical shunts in patients with congenital heart disease

Clinical Study to Individual Treatment for Major Aortopulmonary Collaterals of Tetralogy of Fallot

Objectives

To build a guideline for the individual treatment of Tetralogy of Fallot (TOF) with major aortopulmonary collaterals (MAPCAs) and tentatively establish the occlusion index of MAPCAs.

Methods

According to the diameter of the aortopulmonary collaterals (R: mm) and the bodyweight of the children (weight: kg), K= ((∑R²)/Wt) was set as the occlusion index of TOF with MAPCAs. A retrospective study was initially performed in 171 patients who suffered from TOF with MAPCAs and underwent cardiac malformation repair to investigate the intervals of the K value: K≥2, 1<K<2, and K≤1. In order to examine the reliability of the intervals derived from the retrospective study, a prospective study was conducted in the following 209 cases. When K≥2, the collaterals occlusion was performed immediately behind surgical corrections. The postoperative condition changes in patients with 1<K<2 were observed first and managed by extending mechanical ventilation, while taking further treatments as their conditions worsen. As for patients with K≤1, no occlusion was performed. Finally, the circumstances of collaterals occlusion, postoperative ventilator assist time, and ICU resident time were collected and analyzed.

Result

The proportion of the patients treated with occlusion and the postoperative ICU resident time (p<0.05) in patients with 1<K<2 in the prospective study did dramatically decrease when compared with those of the retrospective studies.

Conclusion

Due to restrictions on medical conditions in China with a large population base, a standard individual treatment of TOF with MAPCAs should be established based on the Aortopulmonary Collaterals Occlusion Index K= ((∑R²)/Wt), which can effectively avoid unnecessary collateral occlusion, minimize trauma, and shorten the length of ICU and hospital stay. When K≥2, the collateral occlusion and surgical correction are recommended to be performed simultaneously. When 1<K<2, whether to occlude collaterals depends on the patients' postoperative conditions with extending ventilator time. When K≤1, do not deal with collaterals.

Two Cases of Transcatheter Closure of Central Aortopulmonary Shunts: One with an Amplatzer Duct Occluder II and One with an Amplatzer Vascular Plug I

When total correction is not possible in infants who have a cyanotic congenital heart disease, creation of a palliative aortopulmonary shunt is essential. A central aortopulmonary shunt is preferable, because of its technical and hemodynamic advantages. Overcirculation, thrombosis, and stenosis of the shunt are the main postoperative sequelae that necessitate urgent reintervention. Percutaneous transcatheter closure of aortopulmonary shunts can eliminate the need for reoperation and substantially decrease postoperative morbidity and mortality rates. We report our successful transcatheter closures of central aortopulmonary shunts in a 3-month-old infant and a 15-year-old girl, with use of an Amplatzer Duct Occluder II and an Amplatzer Vascular Plug I, respectively. To our knowledge, this is the first report of the transcatheter closure of central aortopulmonary shunts with these 2 devices.

Percutaneous closure of Blalock-Taussig shunts using Gianturco coils

Permeability of a Blalock-Taussig shunt can increase the risk of endocarditis and ventricular overload. Percutaneous embolization of these shunts gives variable results. We report our experience in 10 patients with percutaneous closure of modified Blalock-Taussig shunts using retrograde arterial embolization with Gianturco coils. The patients' median age was 2.8 years, and their median weight was 12 kg. Most patients had minor stenosis of the distal portion of the anastomosis. In all cases, complete closure of the shunt was achieved without complications using a median of one coil per patient. The technique was feasible, safe, effective, and inexpensive.

Hybrid approach to surgical correction of tetralogy of Fallot in all patients with functioning Blalock Taussig shunts

BACKGROUND

In total surgical correction of tetralogy of Fallot (TOF) with functioning Blalock Taussig shunts (BTS), shunt take down increased surgical time, bleeding, and might injure phrenic and recurrent laryngeal nerve and thoracic duct.

OBJECTIVES

A routine hybrid approach using transcatheter BTS closure immediately before total surgical correction of TOF in all patients might reduce these problems. We analyze the safety and feasibility of this approach.

METHODS

Transcatheter BTS closure was achieved using single or multiple stainless steel embolization coils, Amplatzer vascular plugs, or duct occluders. When coils were released without control by bioptome forceps, coil migration in larger shunts was prevented by proximal or distal balloon occlusion.

RESULTS

This routine hybrid strategy was followed in 22 consecutive patients aged 1-13 years over 4-year-period and 21 procedures were successful. Among the 16 patients attempted with coils, 13 had successful closure, 2 needed Amplatzer duct occluder devices, and 1 sent for surgical shunt takedown due to acute angulation of the shunt. New Amplatzer vascular plugs were used in six patients. Bioptome was used in six patients and proximal or distal balloon occlusion of flow was used in three patients. Four patients had closure of associated aortopulmonary or chest wall collaterals.

CONCLUSION

Hybrid approach using routine transcatheter closure of all BTS immediately before surgical correction of TOF shunts with coils/plugs/devices is safe, feasible, and reproducible.

Advanced embolization techniques

The techniques of transcatheter embolization of unwanted blood vessels in patients with congenital heart disease have evolved considerably during the past 25 years. There are many different anatomical lesions requiring different approaches and devices. The main types of devices used can be classified into particles, coils, and plugs. It is important for the operator to be familiar with a range of these devices. The results of transcatheter embolization are usually excellent, and technical problems and complications can usually be overcome by attention to detail and persistence. The types of devices in common use and their clinical applications are discussed.

New device for percutaneous closure of aortopulmonary collaterals

A 4.5-month-old infant with tetralogy of Fallot, pulmonary atresia, and multiple aortopulmonary collaterals underwent successful occlusion of the collaterals using a new device. This new plug (Amplatzer vascular plug) is a self-expandable cylindrical device made of nitinol wire mesh. The device is available in sizes from 4 to 16 mm in 2 mm increment. The device can be used in patients with aortopulmonary collaterals, pulmonary arteriovenous malformations, venovenous collaterals, shunts, coronary fistulas, and certain type of patent ductus arteriosus.

Techniques and applications of transcatheter embolization procedures in pediatric cardiology

Transcatheter embolization of congenital or acquired superfluous vascular structure has become routine procedures performed by interventional pediatric cardiologists. Embolization procedure is often part of a collaborative effort with cardiac surgeons to palliate complex congenital heart defect, such as in embolizing aortopulmonary collateral arteries in patient with single ventricle physiology. In other cases, the procedure is the definitive treatment as in embolizing coronary artery fistula. Pediatric cardiologists performing embolization procedures should be familiar with available technologies as well as understand the underlying cardiac anatomy and pathophysiology. This article provides a comprehensive review of presently available embolization agents and technologies. Some of the technologies are used only by interventional radiologists but may be useful to pediatric cardiologists. Specific clinical applications in pediatric cardiology are also discussed with summary of current literature. With continue advancement in transcatheter technology and operator expertise, all unwanted vascular communication should be amenable to transcatheter embolization.

Pulmonary Atresia with Intact Ventricular Septum

The prognosis for patients with pulmonary atresia with intact ventricular septum is poor with and without conventional surgical treatment. Because of this reason, a comprehensive program of medical, transcatheter, and surgical treatment is necessary to improve the long-term outlook of these infants. Algorithms of management plans should be developed based on the presence of right ventricular-dependent coronary circulation as well as size and morphology of the right ventricle. In a tripartite or bipartite right ventricle, transcatheter radiofrequency perforation is preferable. Alternatively, surgical valvotomy may be performed. Augmentation of pulmonary blood flow by prolonged infusion of prostaglandin E(1), stenting the ductus, or a surgical modified Blalock-Taussig shunt may be necessary in some of these patients. In patients with a unipartite or very small right ventricle or a right ventricular-dependent coronary circulation (Tricuspid valve Z score < -2.5), augmentation of pulmonary flow along with atrial septostomy should be undertaken. Follow-up studies to determine the feasibility of biventricular repair should be undertaken and, if feasible, surgical or transcatheter methods may be used to achieve the goals. If not suitable for biventricular repair, one-ventricle (Fontan) or one and one-half ventricular repair should be considered. Comprehensive and well-planned treatment algorithms may help improve survival rate.

Management of paediatric patients undergoing diagnostic and invasive cardiology procedures

Since diagnostic cardiac catheterization in children with congenital heart disease was first reported in 1947, echocardiography has been used as a non-invasive diagnostic tool in congenital heart disease, resulting in a decrease in diagnostic cardiac catheterizations. However, the total number of cardiac catheterizations remained at a steady level until the mid-1980s and has since increased progressively. This is a result of the introduction of interventional transcatheter techniques to improve or correct congenital heart malformations. Since the first description of balloon atrial septostomy, the range of indications for such techniques has steadily increased, particularly in the past 15 years. 'Deep' sedation or general anaesthesia is essential for the conduct of cardiac catheterization in children, particularly in the younger age group.