Neonatal Cardiac Interventions: An Indian Perspective

Transcription

1 Symposium on Advances in Cardiology-II Neonatal Cardiac Interventions: An Indian Perspective Vikas Kohli Pediatric Cardiology & Congenital Cardiac Surgery Unit, Indraprastha Apollo Hospital, New Delhi, India ABSTRACT Palliative interventions in newborn have been performed ever since balloon atrial septostomy was started. The scope and potential of these interventions have been extended to therapeutic interventions and also to replace palliative surgeries. The advancements have happened over the last two decades mainly due to the advancements in cardiac anesthesia of the newborn and primarily due to available hardware improving. The outcomes of these interventions have also improved significantly. The advantage of neonatal interventions is especially relevant in developing countries where limited resources, cost of procedure (lower with reused consumables), lower morbidity due to shorter ICU stay work in favor of the patient. Not only have newborn interventions become well established in centers specializing in pediatric cardiac care, but also premature babies requiring interventions have become successful. This article focuses on the spectrum of neonatal interventions in a contemporary pediatric cardiac centre in India. [Indian J Pediatr 2009; 76(2) : ] vkohli_ md@yahoo.com Key words: Congenital heart disease; Cardiac interventions; Angioplasty; Stent deployment Neonatal cardiac disease presents unique challenges related to the size of the baby, severity of illness and transitional changes from fetal to neonatal life. The early neonatal pulmonary hypertension due to higher pulmonary vascular resistance modulates the manifestation of the disease as also alters the timing of the procedure planned. Over the last several decades advances in management of neonatal cardiac surgery has led to better outcomes in neonatal cyanotic heart diseases requiring neonatal surgery. Similar advances in interventional hardware has improved the potential of interventions in neonates. Improving premature baby care has also contributed to better outcomes of neonatal cardiac procedures. Several case studies have reported the outcomes of neonatal intervention for specific conditions. 1,2,3 This article focuses on neonatal interventions in the current era and the scope and outcomes of these procedures in a contemporary centre in India. SPECTRUM OF NEONATAL INTERVENTIONS Neonatal interventions have been restricted to balloon atrial septostomy for the large part of 90 s. Since then, aortic and pulmonary valvuloplasty have also been Correspondence and Reprint requests : Dr Vikas Kohli, C-116, Sarita Vihar, New Delhi , India Phone No: Fax: [Received January 1, 2009; Accepted January 1, 2009] Abbreviations PDA = patent ductus arteriosus HLHS = Hypoplastic Left Heart Syndrome TAPVD = Total anomalous pulmonary venous drainage MAPCA = Multiple Aorto-pulmonary artery collaterals TGA = Transposition of great arteries PA = Pulmonary stenosis LV = Left ventricle BT Shunt = Blalock-Taussig Shunt MPA = Main pulmonary Artery RVOT = Right ventricular outflow tract PA = Pulmonary atresia VSD = Ventricular septal defect added to procedures performed in this age group. Beyond these interventions, the scope has in the current decade expanded to palliative interventions in complex conditions using stents as a mode of improving the condition of the baby. Table 1 provides a list of interventions performed on newborns by the author over a 4 year period. As noted in this list, stenting of aorta, duct and pulmonary artery are evolving interventions which shall come into the forefront as technology advances. In the series described, there was one death on table PDA stenting in a patient with HLHS. No other mortality from the procedures was noted. Indian Journal of Pediatrics, Volume 76 February,

2 Vikas Kohli TABLE 1. Neonatal Interventions Performed (2003-7) Total = 124 Balloon Atrial septostomy 35 VALVULOPLASTY Pulmonary Valve 15 Aortic Valve 12 Coarctation of aorta balloon dilatation 12 Diagnostic angiograms 14 STENTING PDA Stenting 6 Aortic Stenting 4 Misc Stenting TAPVD 2 MAPCA 4 Pulmonary Valve perforations 2 Non-cardiac interventions 8 Foreign body retrieval 2 Thrombectomy 4 Pericardiocentesis 4 INTERVENTIONS RELATED TO THE ATRIAL SEPTUM Balloon atrial septostomy The commonest neonatal intervention performed in the catheterization laboratory still remains to be atrial septostomy. This is usually a life saving procedure. The procedure is classically required in transposition of great arteries when hypoxia is manifesting secondary to inadequate mixing of the pulmonary and systemic circulations. If atrial communication is adequate this procedure may not be required. Most often the ductus arteriosus alone is not able to maintain adequate mixing. Additional septal defect is necessary. Occasionally a combination of a small duct with a small atrial septal defect can maintain the necessary mixing. The procedure is usually performed as an emergency. It requires a venous access and an uninflated balloon to be passed into the left atrial, inflated there and pulled back into the right atrium with a controlled force. This forceful jerk allows an inflated balloon to open the restrictive atrial septum optimally. Of the balloons available commercially, Numed and Fogarty are available in India. Edwards Miller septostomy balloon is also a preferred balloon but not available in the sub-continent. Of these balloons, Numed is the only one which is an over-the-wire balloon. The Fogarty and Numed balloons are available in various sizes. The balloon septostomy is not a procedure without potential complications. Apart from some of the precautions mentioned in books, the use of echocardiography in the laboratory to ensure inflation of the balloon in the left atrium allows a higher degree of safety. Of late there has been literature which has brought forth the possibility of neurological complications during or after the septostomy procedure 4. The benefit of the procedure has also been questioned and role of prostaglandin highlighted. There does not seem to be an alternative to the procedure when TGA patients present with low saturations. It is essential that the baby have low pulmonary vascular resistance when the arterial switch operation is planned. There may be situations when the saturations do not improve dramatically after the balloon septostomy has been performed. The child may have persistent pulmonary hypertension of the newborn which due to respiratory reasons may not allow adequate saturations 5. Blade septostomy is a procedure performed when the baby is more than a month and the atrial septum is thick and would not allow safe balloon septostomy. In this situation, a blade septostomy would allow a cut to be created in the atrial septum which would then be further extended using a balloon septoplasty. In the rare situation of a hypoplastic left heart or a mitral atresia patient requiring neonatal septal defect creation, blade septostomy may be required. Septoplasty This is an additional procedure which is not dynamic like septostomy. Unlike septostomy, balloons used here are valvuloplasty balloons. The balloon is positioned straddling the atrial septum. In this fixed position, it is inflated and then deflated. It is presumed that this would stretch the atrial septal defect/patent foramen ovale. This procedure performed after balloon or blade septostomy would allow the atrial defect not only to be stretched but to be extended. Septal stent placement to keep the septum open in situations of left sided obstruction (mitral atresia or hypoplastic left heart) has been reported but not actively or aggressively used in the Indian scenario. VALVULOPLASTY Pulmonary Valve This procedure is required to be performed when severe pulmonary stenosis results in a critical degree of stenosis. Critical pulmonary valve stenosis is defined by certain criteria listed in table 2. These would be the indications of performing the procedure in the neonatal period. As would be noted the pressure gradient is not necessarily the main criteria in this age group due to associated pulmonary hypertension which would apparently lower the difference in the right ventricular and pulmonary artery pressures. The procedure involves crossing the pulmonary valve safely using a 208 Indian Journal of Pediatrics, Volume 76 February, 2009

3 Neonatal Cardiac Interventions: An Indian Perspective TABLE 2. Criteria to Define Critical Neonatal Pulmonary Stenosis 1. Severe pulmonary valve stenosis with symptoms attributable to the PS 2. Severe pulmonary valve stenosis with right ventricular dysfunction 3. Suprasystemic right ventricular pressures 4. Severe pulmonary valve stenosis with right to left shunt at patent foramen ovale 5. Fetal heart failure or hydrops 6. Duct dependence in association with pulmonary stenosis coronary wire and then inflating with sequentially increasing balloon diameters across the pulmonary valve. This results in a gradual reduction in right ventricular afterload, preventing the well described condition of suicidal right ventricle. Significant number of newborns after the procedure may not maintain saturations and may shunt right to left across the atrial septum. This is mainly due to the fact that right ventricular diastolic dysfunction (which determines the shunt flow across the atrial septum and not the systolic function) may take several days to few weeks to regress. Apart from right to left shunt causing desaturation, there may a problem related to adequate cardiac output not being maintained due to severe right ventricular hypertrophy resulting in a significantly lowered end diastolic volume. In that situation the cardiac output may need to be maintained by keeping the duct open. Additionally, there may be a small percent of these patients who may be in the subgroup of an associated smaller right ventricle as indicated by a smaller tricuspid annulus (z score below -3). The balloon diameter chosen is in the range of % of the diameter. Choosing a balloon more than 120 % of annulus or close to 140% of the annulus could result in significant pulmonary insufficiency or annular tear. The outcomes of pulmonary valve balloon dilatation in neonatal period have been reported to be excellent with less than 10% patients requiring a repeat procedure 6. It can be considered a curative procedure. Rare patient with persistent tricuspid regurgitation (with normal right ventricular pressures) secondary to the procedure or to congenital abnormality in the tricuspid valve may require late tricuspid repair. Aortic Valve Aortic valve stenosis in the newborn period may be associated with a hypoplastic left ventricle or may be in isolation. This discussion refers to isolated aortic valve stenosis. The presentation of severe aortic stenosis in newborn period may be in the form of a loud murmur or left ventricular systolic dysfunction. When left ventricular dysfunction ensues, the child is critically ill with respiratory distress and low cardiac output. In this situation the child may present in shock and a big heart in which case an echocardiogram will confirm the diagnosis. The cardiac function may also need to be supported with inotropes, the baby will need support of work of breathing with ventilation and then the palliative procedure planned. The child would undergo arterial access entry with the least size sheath available; a coronary wire would then typically be used to cross the aortic valve and the wire positioned away from the mitral valve. The balloon would then be taken and position across the aortic valve with inflation performed with or without pacing. We have performed pacing in all aortic valve balloon dilatations to allow the stroke volume to drop and the balloon being pushed out of position would be unlikely in that situation. Balloons upto 90% of the annulus would be maximally used. Valve morphology has to be defined echocardiographically prior to the procedure. Monocuspid valves are a contraindication; associated significant aortic insufficiency is also a contraindication; mitral insufficiency is usually associated and not a contraindication; co-morbid conditions may include renal dysfunction which may limit the use of contrast in the catheterization laboratory; respiratory failure in the scenario of left ventricular dysfunction is always present. These patients when critically ill tend to improve rapidly after a procedure where the lesion has been taken care of. The left ventricular function improves rapidly over days to few weeks. The mitral regurgitation may resolve gradually as LV geometry improves. The gradient shows an increase due to the improving ventricular function. The gradient usually is falsely low in the situation associated with decreased cardiac function. Long term outlook of patients with aortic stenosis requiring balloon valvuloplasty in the newborn period has been reported as follows: about 50% patients require a repeat procedure in the next 8 years; about 20% patients will require surgery in the same period and 10% patients do not survive this duration 7. PULMONARY VALVE BALLOON DILATATION IN TOF This intervention has been described in literature and is used to palliate a patient to avoid a Blalock-Taussig shunt. Selection of patients is important in this situation. Outcomes in these subgroup of patients have been reported and BT shunt has been avoided in these situations as an end point of the intervention. This has also been reported to be the procedure of choice in premature patients with tetralogy of Fallot who are desaturated and requiring a shunt. 8.9 Indian Journal of Pediatrics, Volume 76 February,

4 Vikas Kohli PULMONARY ATRESIA-INTACT SEPTUM: PERFORATION OF THE PULMONARY VALVE This is a lesion requiring surgery or intervention in the newborn period. After anatomic assessment including that of tricuspid valve z score and ruling out coronary dependence, the procedure should be planned. Several algorithms have been described to decide the treatment. Options include single ventricle pathway, one-and-ahalf ventricle pathway or biventricular pathway. The possibilities include creation of a BT shunt; surgical valvotomy with a BT shunt; perforation of the valve with or without stenting of the patent ductus arteriosus. If the course and pathway chosen includes perforation, there are 2 ways one can use: either a radiofrequency ablation or wire puncture. We have performed wire puncture in 2 patients at our Centre (Fig 1). Excimer laser puncture has also been described but not reported from India. Perforation using Bayliss radiofrequency system has been reported from India 2. There are pre-assembled systems now available which are compatible with the Bayliss radiofrequency ablation system, which allow wire entry, balloon preassembled over the wire and catheter entry. This intervention could be associated with perforation of the right outflow tract. Fig 1. Pulmonary Atresia, Intact Ventricular Septum: Panel on left shows catheter across PDA in MPA and a catheter in RVOT. Panel on the right shows wire tip in PA after perforation. NEONATAL COARCTATION BALLOON DILATATION There are few indications for balloon dilatation of coarctation in the neonatal period. Balloon dilatation in neonatal period is associated with a near 100% recurrence rate. This is mainly due to the recoil and elasticity of the aortic tissue in newborns. Rao et al have shown repeated balloon dilatation in the infants upto 3 times in the first year will result in resolution of the coarcted segment. 10,11 The specific indications for balloon dilatation in neonatal period are enumerated in table 3. In our experience the most common indication for salvage TABLE 3. Indications for Balloon Dilatation of Coarctation in Neonatal Period 1. Severe pulmonary hypertension 2. Severe left ventricular systolic dysfunction 3. Non-cardiac contraindications to surgery: a. Neonatal enterocolitis b. Renal Failure c. Bleeding disorder 4. Extreme prematurity balloon angioplasty of the aorta in neonatal period is severe left ventricular systolic dysfunction resulting in severe pulmonary hypertension. The severe pulmonary hypertension and the LV dysfunction would be difficult to handle with the clamping of the aorta. We have performed this procedure when prostaglandin infusion has not helped in opening the duct to relieve the obstruction or patient has presented so late that prostaglandin is not expected to work. Prematurity has also been the indication in another patient of ours. We have performed balloon angioplasty on a 1 month 1600 gram baby who had not gained weight over 1 month period. The child required 1 more angioplasty and has had a normal aortic arch since then till 2 years of age. After salvage balloon angioplasty in this situation, the child shows rapid improvement of the LV function. The pulmonary hypertension should resolve simultaneously. Once the child has been discharged and develops re-coarctation, as would be expected, further intervention or surgery is planned (depending on family preference of one surgery or repeat interventional procedures). In our experience, there has been a smaller group of neonatal coarctation with fair to good left ventricular function but severe pulmonary hypertension. In this group the pulmonary hypertension has not resolved even with resolution of the arch obstruction; and with recurrence of the arch obstruction following angioplasty, the pulmonary hypertension has worsened. Even surgical resolution of the obstruction subsequently did not result in relief of obstruction and resulted in mortality. Non-resolution of neonatal pulmonary hypertension may be the cause of the problem. Early recognition of this subgroup is important to define the course of illness and plan of management. AORTIC STENTING IN NEWBORNS Stenting of the coarcted aorta in the newborns is associated with problems related to the stented segment not growing while rest of the aorta does. This results in later narrowing of the stented segment. Since the stent gets incorporated in the wall of the aorta, the stent and 210 Indian Journal of Pediatrics, Volume 76 February, 2009

5 Neonatal Cardiac Interventions: An Indian Perspective that segment of aorta have to be surgically removed at a later stage. Aortic stenting in newborns has been reported earlier. 12 We have performed 2 aortic stenting in newborn age group. Both have been performed in the premature babies, both post-operatively on the first day after surgery. Both babies were 1800 grams weight, underwent arch repair and correction of near interruption, and had stent implantation on the first post-operative-day (Fig. 2). The stent implantation in first baby was done in such a way that the narrowest diameter was dilated less than the pre and post diameter. This implied the stent was touching the aortic wall only at the narrowest point and was in the lumen of aorta rest of the length. This allowed an easy surgical removal when the complete repair with VSD closure was done. Fig. 2. Aortic Stenting: Panel on left shows premature baby post interruption repair. The panel on right shows the Stent in place and the obstruction is overcome. The role of bio-absorbable stents implantable through smaller groin sheaths may be a possibility in the future for neonatal coarctation, if proven safe. NEONATAL PULMONARY ARTERY BALLOON DILATATION DUCTAL STENTING IN CYANOTIC HEART DISEASE Large series of patients have been reported in International literature with PDA stenting in newborns with duct dependent cyanotic congenital heart disease. The condition where this intervention is performed includes pulmonary atresia with confluent branch pulmonary arteries. Branch pulmonary artery stenosis and a tortuous duct are a contraindication to the procedure. Similar pulmonary blood supply source with single ventricle physiology is also a subgroup where the same intervention has been tried. There have been reports from India about this intervention 3. In national presentations the intervention and its series have been presented. No single Indian centre has yet adopted a policy of primary stenting of the duct over BT shunt as a policy or performed a trial comparing the 2 head on. As hardware advances, this intervention may be performed more often in newborns over the BT shunt. We have performed ductal stenting in 6 patients. All were performed in children under 3 months of age except for one who was 1.5 year of age. Arterial access for stent deployment was used in 2 patients and venous access (via VSD to ascending aorta) for stent deployment in 4 patients. Delivery sheath was used in 3 patients and in 3 the stent was delivered over the wire without a guiding catheter (mainly due to size of guiding being too big for newborn artery). Cut pigtail catheter was used in all patients for entry to duct though attempt with right Judkins was made in the initial patients. Coronary wire was used for entering the ductus in all patients. No episode of desaturation was noted in any patient with successful stent deployment. Stenting was attempted in 1 additional patient but due to desaturation, the procedure was abandoned and a BT shunt was performed. No mortality was noted from this procedure (Fig. 3). There may be rare indications for this intervention in the neonatal period. Ductal insertion site narrowing has been well described in infants and occasionally in newborns. The narrowing may get severe enough that it may affect lung perfusion or threaten complete cut-off of blood supply. Though we have never faced this situation, it has been reported in newborns. We have faced a situation where a single ventricle palliation being in a 2 month old baby with double inlet single ventricle and one of the branch pulmonary artery was severely narrowed. The intervention included balloon dilatation of the branch pulmonary artery followed by palliative arch repair and pulmonary artery banding. Pulmonary artery stenting has also been described in this situation. Fig. 3. PDA Stenting in ToF: The angiogram shows catheter through the right aortic arch into the left subclavian artery from which the duct was arising; the stent in the PDA is noted. Indian Journal of Pediatrics, Volume 76 February,

6 Vikas Kohli Excellent immediate results and good medium term results have been reported in larger series. 13 The author anticipates the procedure would become standardized with better hardware to engage the ductus (vertical) and a neonate friendly arterial delivery guiding catheter. DUCTAL STENTING IN HYPOPLASTIC LEFT HEART SYNDROME performed and the post-operative morbidity reduced by decreasing the pulmonary hypertension. We have performed this procedure in 1 such baby with supracardiac TAPVD (Fig 5). The procedure was performed as compassionate care when surgery could not be performed due to respiratory infection. Under cover of antibiotics, the stenting was performed. The pulmonary pressures were systemic to suprasystemic in 3 patients and returned to normal within a week. HLHS in India is not a condition which is routinely treated in the way it is in the West 14. This may be mainly related to the cost of multiple procedures and risk of mortality associated at each level. Inspite of these issues, we undertake to counsel all parents with HLHS baby about all options. We report a single patient experience with catheter laboratory ductal stenting and per-operative branch PA banding. The branch PA banding was performed prior to the stenting. The procedure was undertaken after a lot of deliberation. It appeared that the duct was very large already and was not going to narrow or stenose. During the procedure a 7X17 mm stent was deployed along the length of the ductus arteriosus (Fig. 4). Post-deployment, while the deflated balloon was being withdrawn, the baby became bradycardic and arrested. This may be related to heart block secondary to the balloon near the atrioventricular node. Fig. 5. TAPVD Vertical Vein stenting: Panel on left shows angiogram through the vertical vein with arrow pointing at the level of obstruction. Panel on right shows levophase of PA injection with stent in place. STENTING OF AORTO-PULMONARY COLLATERALS Fig. 4. Hypoplastic left Heart Syndrome: Picture shows stent in place in the PDA. STENTING OF OBSTRUCTIVE ANOMALOUS PULMONARY VEINS Total anomalous pulmonary veins with obstruction are a surgical emergency. This condition may be associated with high mortality in the newborns in the Indian scenario. Lack of newborn transport of the critically ill ventilated baby in India may be the reason of higher mortality. Also, not all centers are equipped with nitric oxide. In this situation, if the obstruction is amenable to stenting (i.e. supracardiac or cardiac) the same may be This procedure has been used to palliate end stage cyanotic heart disease in adolescents when no other means of improving cyanosis is available. In the newborns this may serve to open the collaterals to allow them to get adequate blood supply. This results in improved oxygenation. Further surgery could be done once the baby has grown. The problem could be related to the collaterals with stent which cannot be rehabilitated due to metal in them. The author has performed this intervention in a newborn with pulmonary atresia, VSD, MAPCA s who underwent an attempt at unifocalisation but could not be done. The child then was taken up for stenting of collaterals to improve the saturations (Fig 6). TRANS-CATHETER FLOW RESTRICTOR IMPLANTATION Flow restrictor is an interesting concept for restriction of blood flow to the lungs as an alternative to pulmonary artery banding. It was initially introduced as part of total catheter laboratory based Norwood stage 1 with transcatheter flow restrictor implantation and PDA 212 Indian Journal of Pediatrics, Volume 76 February, 2009

7 Neonatal Cardiac Interventions: An Indian Perspective TABLE 4. Interventions on Premature Babies Type Number Weight (Kg) Immediate Outcome Complications Follow Up (months) PVB 4 1.8,1.9, 2, 2.1 no significant gradient none no late recurrence (12-36) AoVB 2 2.0, 1.9 re-ballooning in 1 mo in 1 re-ballooning no late recurrence (24-36) Foreign body retrieval intubation during procedure (48) ToF PVB 2 1.6, 1.8 desaturation in 1 none total repair done both (36) Aortic stenting 2 1.8,1.8 resolution of gradient none 1:late mortality pulm (36 ) Coa balloon 4 1.6, 1.8,2, 2.2 improved LV funct recurrence: 4 re-balloon 3, surgery 1 (6-48) Fig. 6. Pulmonary Atresia, VSD, MAPCAs: Left panel shows upper collateral stented (note partial stent deployment even at 16 atm: one of the problems of MAPCA stenting) and the lower collateral showing severe proximal narrowing. Right panel shows Stent deployed in lower collateral with good flow. stenting. This subsequently has been replaced by a hybrid procedure with PDA stenting and per-operative branch PA banding. In India flow restrictors may find wider application with late presentation of left to right shunt with early irreversible PAH (non-neonatal). The author has implanted flow restrictor in 2 patients with single ventricle who had presented late (at 1.5 yr) with increased pulmonary blood flow. Though catheter calculations still showed huge pulmonary blood flow with very low pulmonary vascular resistance, surgery for single ventricle pathway was not feasible. On compassionate grounds, flow restrictors were implanted in both children. The PVR remained low and the cardiac size decreased, with branch PA gradient of 70 mmhg. One of these patients has already undergone explantation of the flow restrictor and Glenn shunt (Fig 7). FOREIGN BODY RETREIVAL IN NEWBORNS Peripherally inserted central catheter (PICC) is often used in newborns. The catheter may rarely get displaced. One such case in point is a premature baby with a 20 cm displaced PICC line requiring snaring and retrieval. 15 Though an uncommon intervention, this can make a newborn critically ill. Retrieval can be Fig.7. Single Ventricle, Increased pulmonary blood flow: Left panel shows still frame from PA angiogram with a flow restrictor in each pulmonary artery. Note the proximal and distal markers prominently noted with each flow restrictor. Right panel shows picture of flow restrictor. challenging in a small baby with a large line which may have potential of knotting. INTERVENTIONS IN PREMATURE BABIES The author has performed 15 interventions in premature babies including pulmonary valve balloon dilatation, aortic valve balloon dilatation, balloon dilatation in premature babies with ToF, coarctation balloon dilatation, foreign body retrieval and aortic stenting. Table 4 shows the interventions and outcomes of interventions in the premature babies. No mortality was noted related to the procedure. Long term follow up has also shown outcomes to be comparable with similar interventions in term babies. This is comparable to interventions in premature babies reported in literature. 16 CONCLUSION Neonatal and even premature baby interventions have come of age in India. Large numbers of therapeutic and palliative neonatal interventions are being performed with good results in India. In the future, PDA stenting in Indian Journal of Pediatrics, Volume 76 February,

8 Vikas Kohli cyanotic congenital heart disease is a definitive intervention which would help decrease the morbidity of neonatal palliative surgery by replacing neonatal BT shunts. REFERENCES 1. Saxena A, Naik N, Juneja R. Aortic valve balloon dilatation in a newborn for critical aortic stenosis diagnosed during fetal life. Indian Heart J 2001;53: Kothari SS, Sharma SK, Naik N. Radiofrequency perforation for pulmonary atresia and intact ventricular septum. Indian Heart J 2004;56: Mahesh K, Kannan BR, Vaidyanathan B, Kamath P, Anil SR, Kumar RK. Stenting the patent arterial duct to increase pulmonary blood flow. Indian Heart J 2005;57: Miller SP. Balloon atrial septostomy is associated with preoperative stroke in neonates with transposition of the great arteries. Circulation 2006; 113: Roofthooft MT, Bergman KA, Waterbolk TW, Ebels T, Bartelds B, Berger RM. Persistent pulmonary hypertension of the newborn with transposition of the great arteries.ann Thorac Surg 2007;83: Tabatabaei H, Boutin C, Nykanen DG, Freedom RM, Benson LN.Morphologic and hemodynamic consequences after percutaneous balloon valvotomy for neonatal pulmonary stenosis: medium-term follow-up. J Am Coll Cardiol 1996;27: Han RK, Gurofsky RC, Lee KJ, Dipchand AI, Williams WG, Smallhorn JF, McCrindle BW. Outcome and growth potential of left heart structures after neonatal intervention for aortic valve stenosis. J Am Coll Cardiol 2007; 50: Kohli V, Azad S, Sachdev MS, Joshi R, Makram ER.Balloon Dilation of the Pulmonary Valve in Premature Infants with Tetralogy of Fallot. Pediatr Cardiol 2008;29: Kohli V. Balloon dilatation of pulmonary valve in Tetralogy of Fallot s. Indian J Pediatr 2005;72: Lee CL, Lin JF, Hsieh KS, Lin CC, Huang TC. Balloon angioplasty of native coarctation and comparison of patients younger and older than 3 months. Circ J 2007; 71: Rao PS, Jureidini SB, Balfour IC, Singh GK, Chen SC. Severe aortic coarctation in infants less than 3 months: successful palliation by balloon angioplasty. J Invasive Cardiol 2003;15: Holzer RJ, Chisolm JL,Hill SL,Cheatham JP. Stenting complex aortic arch obstructions. Catheter Cardiovascular Interventions 2008;71: Alwi M, Choo KK, Latiff HA, Kandavello G, Samion H, Mulyadi MD Initial results and medium-term follow-up of stent implantation of patent ductus arteriosus in ductdependent pulmonary circulation. J Am Coll Cardiol ;44: McQuillen PS, Hamrick SE, Perez MJ et al. Hybrid approach for hypoplastic left heart syndrome: intermediate results after the learning curve. Ann Thorac Surg 2008;85: Kohli V, Joshi R. Central line retrieval in a neonate. Indian J Pediatr 2007;74: Sutton N, Lock JE, Geggel RL.Cardiac catheterization in infants weighing less than 1,500 grams. Catheter Cardiovasc Interv 2006;68: Indian Journal of Pediatrics, Volume 76 February, 2009