Transcatheter intervention can be effectively performed in children with congenital heart diseases (CHD) to close the abnormal shunts (secundum atrial septal defect (ASDII), patent ductus arteriosus (PDA), ventricular septal defect (VSD)), dilate the stenosis (pulmonary stenosis) and create a pathway through the atretic outflow (pulmonary atresia with intact ventricular septum). From the latest reports, though the incidence of CHD varies, the variation can be well explained by the variation of the proportion of VSD in the study cohorts. To delineate the potential patient loads from CHD patients who may require transcatheter cardiac intervention, the epidemiological data from five countries of Eastern Asia, i.e., China, Hong-Kong, Japan, Korea and Taiwan, were collected from the literature. The population data are obtained from Unicef website. We found that the incidence of CHD in these five countries varied from 6.35 to 14.77/1,000 live births. The average CHD-specific incidence was 1.14, 1.15, 1.19, 3.82 and 0.08 per 1000 live births for ASDII, PDA, pulmonary stenosis, VSD and pulmonary atresia with intact ventricular septum. The proportion of perimembranous VSD in the whole VSD patients was estimated from MACDP registration data as 25%. Potential load patient load for transcatheter intervention will be projected. These figures will provide us the basis of future planning for medical care policy-making and medical care personnel training strategy-decision.

Surgical repair of ventricular septal defects (VSD) has been clinically performed for decades and considered as the gold standard therapy up to date. However, it is associated with morbidity and mortality. Catheter intervention for VSD with different-shaped double-disc occluders based on self-expandable materials (AmplatzerTM , HeartrTM, CeraTM, etc.) has been clinically used for years and considered as alternative in selected patients. Transcatheter closure for muscular VSD (mVSD) has shown advantages to surgical repair. As for perimenbranous VSD (pmVSD), clinical outcome, with advantages as well as disadvantages, are under intensive evaluation. From 1999 to 2007, 509 VSD patients received transcatheter closure with AmplatzerTM (asymmetric) or HeartrTM (asymmetric, symmetric, larger-left-disc) occluders in Guangdong Cardiovascular Institute. Here we shared our technical experiences in catheter manipulation and device selection, as well as intermediate- to long-term follow-up results. We reached conclusions as listed below:

1. Transcatheter closure of pmVSD is safe and effective.
2. Both asymmetric and symmetric occluders are equally effective for VSD closure.
3. Both asymmetric and symmetric occluders have similar risk of major complications including hemolysis, complete atrio-ventricular block, severe aortic or tricuspid regurgitation.
4. Asymmetric occluders have increased risk of minor complications, such as mild arrhythmias and instant residual shunt.
5. Device selection must be individualized.

For many decades, systemic to pulmonary shunt (Blalock Taussig Shunt) is a widely performed palliative cardiac surgery for cyanotic heart disease. It allows relatively normal growth before corrective surgery can be performed at a later age. Advances in paediatric cardiac surgery and post operative care has allowed complex cyanotic cardiac lesions to be repaired early in infancy, obviating the need for palliative surgery. However a number of lesions with duct dependent pulmonary circulation can still be corrected only at a later age and Blalock Taussig shunt remains an important part of the management.

In the modern era, Blalock Taussig shunt is almost exclusively performed in the neonatal period.   This accounts for the significant morbidity of this procedure such as early shunt thrombosis and those related to thoracotomy such as diaphragmatic paralysis and chylothorax.

With advances in percutaneous coronary interventions, applying coronary stents to maintain PDA patency is less invasive and attractive alternative to Blalock Taussig shunt. Earlier attempts to maintain ductal patency by formalin infiltration and use of heated balloons have not been successful.   Results of PDA stenting has been encouraging. However, there are a number of pertinent issues.  Unlike the PDA as an isolated lesion, the ductus in cyanotic heart disease have a remarkable morphologic variability.  The ductus tends to arise more proximally under the aortic arch, giving rise to a vertical PDA or occasionally it may arise from the subclavian artery. It also tends to be long and sometimes very tortuous, rendering stent implantation technically impossible. The ductus in these patients may also insert onto one of the branch pulmonary arteries with some stenosis at the site of insertion (“pulmonary coarctation”). Stenting the PDA in this situation accelerates and exaggerates this pulmonary coarctation.

With regards to clinical research, issues of concern are performing a procedure which has relatively high risk against a standard surgical procedure albeit with known serious complications. The variation in ductal morphology also raises concerns regarding patient selection and contra-indication to the procedure. 

As a new procedure, documentation and close follow up are important in order that safety and efficacy data can be established to be measured against standard surgical procedure, and to see wether it merits a place in the routine management of complex cyanotic congenital heart disease.

Atrial septal defect (ASD) may escape detection in childhood because symptoms related to ASD are mostly subtle. Many patients can survive to an old age without correction, however, many of them become symptomatic with dyspnea and palpitation. Pulmonary artery hypertension, heart failure and arrhythmia are frequently present in the elderly patients. Pulmonary artery pressure may decline after closure but many of them continue to have pulmonary arterial hypertension and require medications. Persistent atrial fibrillation rarely subsided after catheter closure. Heart failure may improve after closure. Surgical closure is the traditional method of treatment for ASD. Transcatheter closure has recently been considered as superior to surgery. There are many advantages of catheter closure over surgery especially in the elderly where the risk of surgery is significantly higher. However, long-term follow-up is mandatory to explore the benefits of transcatheter closure of ASD in the elderly.

Previous results show that the success rate of balloon angioplasty for pulmonary artery stenosis is about 50% to 60%. We have performed balloon angioplasty in 183 patients, before intracardiac repair in 26 patients, and after intracardiac repair in 157 patients. Most patients had congenital heart defects other than pulmonary artery stenosis. A total of 257 balloon angioplasty procedures were performed in 183 patients and the success rate was 60%. We analyzed the factors which influenced the success rate. The interval between operation and balloon angioplasty was important in patients with transposition of the great arteries after arterial switch operation. In 39 stenotic lesions, the success rate was about 50%. In patients who underwent balloon angioplasty less than 3.5 years after surgery, the success rate was 92%. We used a high-pressure balloon in a systemic fashion. We initially used low-pressure balloons. If the stenosis cannot be dilated with the low-pressure balloons, then we used high-pressure balloons.  The success rate with the use of low- pressure balloons was 47%. With the use of high-pressure balloons, however, the success rate increased to 65%. Thus, the high-pressure balloon improves the success rate of balloon angioplasty. There are limitations in balloon dilation for pulmonary artery stenosis, which are: low success rate, unexpected complications, and re-stenosis. Especially, there is a stenotic pulmonary artery which is dilated easily but recoils easily. The stent is an effective way to dilate such a stenosis. Although several types of stents are available, the Palmaz stent has been usually used to dilate the pulmonary artery. The procedure with the use of stents dilated the stenoses which could not be dilated by balloon  and the success rate of catheter treatment  using stents  increased to  80 -90%. The mid-term results of balloon angioplasty using stents are excellent and restenosis rate is low (less than 3%. Intimal hyperplasia may occur on the surface of the implanted stent, but that may cause re-stenosis usually only in the small arteries. Successful balloon angioplasty results from intimal and medial tears. We have been using intravascular ultrasound (IVUS) in an attempt to improve the success  rate. We use IVUS in all patients who undergo balloon angioplasty to detect  the wall morphology. IVUS gives us useful information which help us to decide whether  larger balloons should be used or not. The success rate of balloon angioplasty with the use of IVUS was 85%. Major Complications  can occur in the balloon angioplasty for pulmonary artery stenosis. In 183 patients at our institution, major complications occurred in 3%.  Perforation in 3 patients, resulting in false aneurysm, did not require surgical treatment. Perforation to the aorta in 2 patients was fixed surgically. Tricuspid regurgitation occurred in one patient and it was repaired surgically. No death has occurred at our institution. In conclusion, balloon angioplasty for pulmonary artery stenosis can be performed with a high success rate 1) by performing it at an appropriate time, 2) by using high-pressure balloons, 3) by using stents, and 4) by using IVUS.