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Peri-procedural outcome of transcatheter interventions for congenital heart diseases in children in a tertiary level hospital in South Tamil Nadu, India

Catheter based therapies are available for a wide variety of congenital cardiovascular defects. Transcatheter occlusion devices are available to safely and effectively treat patients with ostium secundum atrial septal defects (ASD), ventricular septal defects (VSD) and patent ductus arteriosus (PDA). Balloon dilatation has become an effective means to relieve congenital pulmonary stenosis and aortic stenosis. Coarctation of aorta can be managed by non-surgical means either by balloon dilatation or balloon-expandable stenting. With transcatheter based therapies in congenital heart defects (CHD) gaining popularity, the morbidity associated with the correction of these defects has been dramatically reduced. Although technically less challenging, these procedures require accurate assessment of the structure and size of the CHD to be corrected, whether it be a valvular stenosis or a left to right shunt defect. The paediatric cardiologist has to be well trained in these interventional procedures for the successful outcome of these procedures. Our hospital is a tertiary care hospital located in a rural village in south Tamil Nadu with all available infrastructure and technical expertise to carry out these procedures. The patients that we cater to predominantly come from a poor socio-economic ABSTRACT


INTRODUCTION
Catheter based therapies are available for a wide variety of congenital cardiovascular defects. Transcatheter occlusion devices are available to safely and effectively treat patients with ostium secundum atrial septal defects (ASD), ventricular septal defects (VSD) and patent ductus arteriosus (PDA). Balloon dilatation has become an effective means to relieve congenital pulmonary stenosis and aortic stenosis. Coarctation of aorta can be managed by non-surgical means either by balloon dilatation or balloon-expandable stenting. With transcatheter based therapies in congenital heart defects (CHD) gaining popularity, the morbidity associated with the correction of these defects has been dramatically reduced. [1][2][3] Although technically less challenging, these procedures require accurate assessment of the structure and size of the CHD to be corrected, whether it be a valvular stenosis or a left to right shunt defect. The paediatric cardiologist has to be well trained in these interventional procedures for the successful outcome of these procedures. Our hospital is a tertiary care hospital located in a rural village in south Tamil Nadu with all available infrastructure and technical expertise to carry out these procedures. The patients that we cater to predominantly come from a poor socio-economic background and the interventional procedures are done free of cost with the help of a government sponsored health insurance scheme. We conducted this study to ascertain the peri-procedural results of transcatheter interventions for CHD in our hospital and compare it with other major centres.

METHODS
This prospective observational study was conducted in the Department of Paediatrics and the division of Paediatric Cardiology, Sree Mookambika Institute of Medical Sciences, Kulasekharam, Kanyakumari district, Tamil Nadu. We enrolled patients upto 18 years of age who underwent transcatheter interventions for CHD in our hospital from February 2014 to January 2018. A written informed consent was obtained from the parents of all these patients prior to procedure. The children were diagnosed to have ASD, VSD, PDA, pulmonary stenosis (PS), aortic stenosis (AS), and coarctation of aorta. Children with ASD were evaluated by transthoracic echocardiography (TTE). Evaluation before procedure included a standard 12 lead ECG, chest X-ray, and TTE. Transesophageal ECHO (TEE) was used in selected older patients. The initial TTE was done to confirm the diagnosis and then assess the suitability for device closure. Sub costal window, parasternal short axis and apical 4 chamber were used in TTE to determine the location of the ASD, its diameter and all relevant margins. The inferior vena cava margin, superior vena cava margin, atrioventricular valve margin, superior margin, aortic margin, posterior margin and coronary sinus margin were measured. Recommended echocardiography exclusion criterion was used before making a final decision about procedure suitability. Vascular access was obtained from the femoral vein. The Amplatzer septal occluder (AGA Medical Corporation, USA) was the only device used. After the procedure, residual interatrial shunting and device position was examined by TTE or TEE.
Children with VSD were evaluated by transthoracic echocardiography (TTE). Evaluation before procedure included a standard 12 lead ECG, chest X-ray, and TTE. The initial TTE was done to confirm the diagnosis and then assess the suitability for device closure. Sub costal window, parasternal long axis, parasternal short axis and apical 4 chamber were used in TTE to determine the location of the VSD and its diameter. Recommended echocardiography exclusion criterion was used before making a final decision about procedure suitability. Vascular access was obtained from the femoral artery and femoral vein. The Amplatzer ductal occluder I and II (AGA Medical Corporation, USA) were the only devices used. After the procedure, residual interventricular shunting and device position was examined by TTE and left ventricular angiography. Children with PDA were evaluated by transthoracic echocardiography (TTE). Evaluation before procedure included a standard 12 lead ECG, chest X-ray, and TTE. The initial TTE was done to confirm the diagnosis and then assess the suitability for device closure. Parasternal short axis and ductal view are used to determine the diameter and shape of PDA. Vascular access was obtained from the femoral vein and femoral artery (if needed). The Amplatzer ductal occluder I (AGA Medical Corporation, USA) was the only device used. After the procedure, residual PDA shunting and device position was examined by TTE. Children with PS and AS were evaluated by transthoracic echocardiography (TTE). Evaluation before procedure included a standard 12 lead ECG, chest X-ray, and TTE. The initial TTE was done to confirm the diagnosis and then assess the valve characteristics and diameter of valve annulus. Sub costal window, parasternal short axis, parasternal long axis and apical 4 chamber were used in TTE. Recommended echocardiography inclusion and exclusion criterion was used before making a final decision about procedure suitability. Vascular access was obtained from the femoral artery and femoral vein. TYSHAK II balloon was the only balloon used. After the procedure, residual gradient and valve regurgitation was examined by TTE and catheterization measures.
Children with coarctation of aorta was evaluated by transthoracic echocardiography (TTE) and CT angiography of aorta. CT angiography was done to confirm the diagnosis and then assess the diameter of aorta above and below the coarctation and relation of coarctation to adjacent left subclavian artery. Vascular access was obtained from the femoral artery. ATLAS balloon (BARD medical corporation) was the only device used. After the procedure, residual gradient and diameter were determined by pressure measurements and angiography respectively. Demographic profile, size of ASD, VSD and PDA, device sizes, size of valve annulus, size of balloons for dilatation, and complications were tabulated and analyzed using SPSS. p-value taken significant at <0.05.

RESULTS
A total of 125 patients were enrolled in the study during the study period from February 2014 to January 2018.     Long term follow up of these patients are required as many studies have revealed that a small section of children who have undergone transcatheter cardiac interventions can have multiple issues in future, including need for re-interventions. [8][9][10] First and perhaps most importantly, our inclusion and exclusion criteria were vigorous with priority given for safety of procedure and only patients with a suitable anatomy and meeting the criteria were included for the attempted intervention. Second, this is a small-scale study involving only 1 medical centre. A large-scale study is needed to provide a more representative comparison.

CONCLUSION
Based on strict inclusion and exclusion criteria, transcatheter cardiac interventions for CHD is associated with excellent success rates and low mortality or morbidity. The transcatheter approach provides a lessinvasive alternative avenue for open heart surgery. Meticulous planning and proper case selection are the major contributors for the success of any centre. The high success rate and the minimal complication rates of the transcatheter cardiac interventions in our centre is reassuring for any cardiac centre planning to start a paediatric cardiology programme.