**18. Surgical approaches to the correction of congenital cardiac defects:**

A simplified approach to such a variety of congenital cardiac defects is to broadly classify them as


#### **18.1. Left to right shunts**

Left to right shunts are the most gratifying to treat as they are potentially life-saving and promote the growth of the child. The common lesions are atrial septal defect (ASD), ventricular septal defect (VSD) and patent ductus arteriosus (PDA).

The common variations of ASD [29] (figure 5) are ostium secundum, ostium primum, sinus venosus, coronary sinus and various combinations of these. Secundum ASD's are usually closed by the interventional cardiologists percutaneously provided parameters are satisfied including adequacy of rims and the safety of neighbouring structures. When these criteria are not met, surgery is via median sternotomy or right posterolateral or anterolateral thoracotomy (cosmetic), placing on cardiopulmonary bypass (CPB) and closure either directly or using the patient's own (autologous) pericardial patch. Ostium primum ASD is usually associated with abnormal mitral and sometimes tricuspid valves. Repair involves repair of the valves with closure of the ASD with a patch. Failure to close the cleft in the mitral valve increases reoper‐ ation rate for mitral regurgitation [30]. These patients require lifelong follow-up for mitral regurgitation and left ventricular outflow tract obstruction [31] Complete heart block is a potential complication due to the proximity of the bundle of His.

are large VSD with congestive cardiac failure refractory to medical management, left atrial and left ventricular dilatation, aortic valve prolapse and aortic regurgitation and prevention of infective endocarditis [34] Open heart surgery entails closure directly (is small) or patch (Gore-

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Patent ductus arteriousus (PDA) is the persistence of the fetal ductus arterious beyond two months after birth. This results in increased left heart return and failure to thrive with congestive cardiac failure. Most PDA's are amenable to closure by device (intervention) and surgery is done infrequently. Surgical approach is via left posterolateral thoracotomy. (figure

Aortopulmonary window (APW) is a communication between the aorta and pulmonary artery resulting in a large left-to-right shunt. This condition requires early surgical clo‐ sure. This condition is rare and requires early surgery as there is steal from the systemic circulation. Surgical approaches vary but basically consist of division of the APW with su‐

Double outlet right ventricle is a separate and complex entity wherein both great vessels arise predominantly from the right ventricle. When there is a VSD, this results in unrestricted pulmonary blood flow and physiologically is a left-to-right shunt. The classification of DORV by Lev is self-explanatory and the varying anatomy decides the clinical presentation which varies from simple left-to-right shunt, tetralogy of Fallot physiology, transposition of great

tex, Dacron, bovine or autologous pericardium). ( figure 6)

7) [35]

turing of a patch [36]

**Figure 5.** Atrial Septal Defects

Sinus venosus ASD is usually superior vena cava (SVC) ASD with partial anomalous pulmo‐ nary venous connection (usually right upper lobe pulmonary veins draining anomalously to the right atrium instead of left atrium. Surgical options range from simple ASD closure (singlepatch), two-patch technique and Warden's procedure which is more complex [32]. Complica‐ tions range from SVC obstruction, pulmonary venous obstruction and sino-atrial nodal dysfunction. Coronary sinus ASD is rare and involves patch repair. Common atrium is complete absence of interatrial septum and surgery is partitioning of the atria. Autologous pericardial patch is the material of choice.

Ventricular septal defect (VSD) is deficiency of the interventricular septum. There are various classifications based on anatomy and embryology. The commonest classification is perimem‐ branous VSD, muscular VSD, doubly commited subarterial VSD, inlet septal and multiple VSD's. [33] The majority close by one year, particularly perimembtranous and muscular. The doubly committed and inlet septal VSD's do not close spontaneously. Indications for surgery

**Figure 5.** Atrial Septal Defects

**18. Surgical approaches to the correction of congenital cardiac defects:**

as

**1.** left-to-right shunts **2.** cyanotic conditions

**3.** single-ventricle physiology

252 Principles and Practice of Cardiothoracic Surgery

**5.** tracheal and vascular rings

**18.1. Left to right shunts**

**4.** valvular and coronary heart disease

septal defect (VSD) and patent ductus arteriosus (PDA).

potential complication due to the proximity of the bundle of His.

pericardial patch is the material of choice.

A simplified approach to such a variety of congenital cardiac defects is to broadly classify them

Left to right shunts are the most gratifying to treat as they are potentially life-saving and promote the growth of the child. The common lesions are atrial septal defect (ASD), ventricular

The common variations of ASD [29] (figure 5) are ostium secundum, ostium primum, sinus venosus, coronary sinus and various combinations of these. Secundum ASD's are usually closed by the interventional cardiologists percutaneously provided parameters are satisfied including adequacy of rims and the safety of neighbouring structures. When these criteria are not met, surgery is via median sternotomy or right posterolateral or anterolateral thoracotomy (cosmetic), placing on cardiopulmonary bypass (CPB) and closure either directly or using the patient's own (autologous) pericardial patch. Ostium primum ASD is usually associated with abnormal mitral and sometimes tricuspid valves. Repair involves repair of the valves with closure of the ASD with a patch. Failure to close the cleft in the mitral valve increases reoper‐ ation rate for mitral regurgitation [30]. These patients require lifelong follow-up for mitral regurgitation and left ventricular outflow tract obstruction [31] Complete heart block is a

Sinus venosus ASD is usually superior vena cava (SVC) ASD with partial anomalous pulmo‐ nary venous connection (usually right upper lobe pulmonary veins draining anomalously to the right atrium instead of left atrium. Surgical options range from simple ASD closure (singlepatch), two-patch technique and Warden's procedure which is more complex [32]. Complica‐ tions range from SVC obstruction, pulmonary venous obstruction and sino-atrial nodal dysfunction. Coronary sinus ASD is rare and involves patch repair. Common atrium is complete absence of interatrial septum and surgery is partitioning of the atria. Autologous

Ventricular septal defect (VSD) is deficiency of the interventricular septum. There are various classifications based on anatomy and embryology. The commonest classification is perimem‐ branous VSD, muscular VSD, doubly commited subarterial VSD, inlet septal and multiple VSD's. [33] The majority close by one year, particularly perimembtranous and muscular. The doubly committed and inlet septal VSD's do not close spontaneously. Indications for surgery are large VSD with congestive cardiac failure refractory to medical management, left atrial and left ventricular dilatation, aortic valve prolapse and aortic regurgitation and prevention of infective endocarditis [34] Open heart surgery entails closure directly (is small) or patch (Goretex, Dacron, bovine or autologous pericardium). ( figure 6)

Patent ductus arteriousus (PDA) is the persistence of the fetal ductus arterious beyond two months after birth. This results in increased left heart return and failure to thrive with congestive cardiac failure. Most PDA's are amenable to closure by device (intervention) and surgery is done infrequently. Surgical approach is via left posterolateral thoracotomy. (figure 7) [35]

Aortopulmonary window (APW) is a communication between the aorta and pulmonary artery resulting in a large left-to-right shunt. This condition requires early surgical clo‐ sure. This condition is rare and requires early surgery as there is steal from the systemic circulation. Surgical approaches vary but basically consist of division of the APW with su‐ turing of a patch [36]

Double outlet right ventricle is a separate and complex entity wherein both great vessels arise predominantly from the right ventricle. When there is a VSD, this results in unrestricted pulmonary blood flow and physiologically is a left-to-right shunt. The classification of DORV by Lev is self-explanatory and the varying anatomy decides the clinical presentation which varies from simple left-to-right shunt, tetralogy of Fallot physiology, transposition of great

neonatal period. The PA is detached from the aorta and reconnected to the right ventricle utilizing a conduit and closing of the VSD. Alternatives include direct connection of RV-PA utilizing neighbouring tissue. Mid-term and long-term results are determined by the fate of the RVOT- the presence of pulmonary regurgitation and the deterioration of the conduit. [38].

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Coarctation of aorta is narrowing of the aorta near the insertion of the ductus arteriousus to the descending aorta This presents at various stages. Presentation in the neonatal period is usually as an emergency with closure of the ductus and sudden cessation of blood flow to the lower body. Treatment includes commencing prostaglandin to reopen the ductus, commence‐ ment of inotropes and correction of acidiosis. Emergency surgical repair of coarctation is warranted. Surgical techniques are varied and each has merits and demerits. The preferred technique is resection of the coarctation and end-to-end anastomosis [39] Alternatives include subclavian flap plasty and patch plasty. Interruption is total disconnection of the aorta and is usually associated with VSD. The classification is based on the location of the interruption (type A is distal to the left subclavian artery, type B is distal arch and type C proximal arch. Surgery is complex and involves disconnection of the PDA which supplies blood to the lower

Pulmonary vein anomalies are rare and can present as stenosis of individual veins or as they enter the LA as a confluence. Prognosis is poor when all four pulmonary veins are involved

The congenital cardiac conditions are Tetralogy of Fallot (TOF), Transposition of Great Arteries (TGA), Total anomalous pulmonary venous connection (TAPVC), Tricuspid atresia (TA) and

Tetralogy of Fallot(figure 8) is the commonest cyanotic congenital cardiac condition. The condition described originally consists of four components- VSD, overriding of aorta, right ventricular outflow tract obstruction (RVOTO) and right ventricular hypertrophy. The extent and severity of RVOTO accounts for the variation in symptoms. Babies present early with cyanosis or cyanotic spells(due to infundibular spasm). Surgical strategies vary in different parts of the world. In the neonatal period, whenever the baby presents with symptoms, the tendency is surgical correction with closure of VSD and judicious relief of RVOTO. However, most centers follow the policy of performing Blalock-Taussig shunt if the baby presents with symptoms at less than 6 months of age or less than 5 kgs. If older, surgical correction is attempted [ 42].B-T shunt is still performed if the branch pulmonary arteries are hypoplastic or there are significant co-morbidities that preclude placing the baby on cardiopulmonary bypass. The postoperative course varies depending on the anatomically variations. Right heart

B-T shunt is the connection of an artificial conduit between a branch of the aorta and one of the pulmonary arteries. This is a palliative surgery and is associated with complications such as blocked shunt precipitating cardiac arrest, low cardiac output, and pulmonary artery distortion. Historically, there have been several systemic-pulmonary artery shunts. These have

body and reconnection of the two ends of the aorta. The VSD is closed [40].

failure is common due to the non-compliant RV and diastolic dysfunction.

**18.2. Cyanotic congenital cardiac conditions**

Truncus arteriosus.

[41] Surgery or balloon dilatation are both associated with high rates of restenosis.

**Figure 6.** Ventricular Septal Defects.

**Figure 7.** Patent Ductus Arteriosus

arteries physiology to single ventricle physiology. They occur with VSD which then presents as increased pulmonary blood flow. The treatment is surgical closure of VSD with routing of LV to drain into the aorta across the VSD. When they present with VSD and PS, the repair consists of VSD closure and relief of RVOTO with or without conduit. DORV with subpul‐ monic VSD Requires arterial switch and VSD closure [37]

Truncus arteriosus (figure 8) is a condition wherein the pulmonary arteries arise from the aorta directly. This results in torrential pulmonary blood flow and warrants early surgery in the neonatal period. The PA is detached from the aorta and reconnected to the right ventricle utilizing a conduit and closing of the VSD. Alternatives include direct connection of RV-PA utilizing neighbouring tissue. Mid-term and long-term results are determined by the fate of the RVOT- the presence of pulmonary regurgitation and the deterioration of the conduit. [38].

Coarctation of aorta is narrowing of the aorta near the insertion of the ductus arteriousus to the descending aorta This presents at various stages. Presentation in the neonatal period is usually as an emergency with closure of the ductus and sudden cessation of blood flow to the lower body. Treatment includes commencing prostaglandin to reopen the ductus, commence‐ ment of inotropes and correction of acidiosis. Emergency surgical repair of coarctation is warranted. Surgical techniques are varied and each has merits and demerits. The preferred technique is resection of the coarctation and end-to-end anastomosis [39] Alternatives include subclavian flap plasty and patch plasty. Interruption is total disconnection of the aorta and is usually associated with VSD. The classification is based on the location of the interruption (type A is distal to the left subclavian artery, type B is distal arch and type C proximal arch. Surgery is complex and involves disconnection of the PDA which supplies blood to the lower body and reconnection of the two ends of the aorta. The VSD is closed [40].

Pulmonary vein anomalies are rare and can present as stenosis of individual veins or as they enter the LA as a confluence. Prognosis is poor when all four pulmonary veins are involved [41] Surgery or balloon dilatation are both associated with high rates of restenosis.

#### **18.2. Cyanotic congenital cardiac conditions**

arteries physiology to single ventricle physiology. They occur with VSD which then presents as increased pulmonary blood flow. The treatment is surgical closure of VSD with routing of LV to drain into the aorta across the VSD. When they present with VSD and PS, the repair consists of VSD closure and relief of RVOTO with or without conduit. DORV with subpul‐

Truncus arteriosus (figure 8) is a condition wherein the pulmonary arteries arise from the aorta directly. This results in torrential pulmonary blood flow and warrants early surgery in the

monic VSD Requires arterial switch and VSD closure [37]

**Figure 6.** Ventricular Septal Defects.

254 Principles and Practice of Cardiothoracic Surgery

**Figure 7.** Patent Ductus Arteriosus

The congenital cardiac conditions are Tetralogy of Fallot (TOF), Transposition of Great Arteries (TGA), Total anomalous pulmonary venous connection (TAPVC), Tricuspid atresia (TA) and Truncus arteriosus.

Tetralogy of Fallot(figure 8) is the commonest cyanotic congenital cardiac condition. The condition described originally consists of four components- VSD, overriding of aorta, right ventricular outflow tract obstruction (RVOTO) and right ventricular hypertrophy. The extent and severity of RVOTO accounts for the variation in symptoms. Babies present early with cyanosis or cyanotic spells(due to infundibular spasm). Surgical strategies vary in different parts of the world. In the neonatal period, whenever the baby presents with symptoms, the tendency is surgical correction with closure of VSD and judicious relief of RVOTO. However, most centers follow the policy of performing Blalock-Taussig shunt if the baby presents with symptoms at less than 6 months of age or less than 5 kgs. If older, surgical correction is attempted [ 42].B-T shunt is still performed if the branch pulmonary arteries are hypoplastic or there are significant co-morbidities that preclude placing the baby on cardiopulmonary bypass. The postoperative course varies depending on the anatomically variations. Right heart failure is common due to the non-compliant RV and diastolic dysfunction.

B-T shunt is the connection of an artificial conduit between a branch of the aorta and one of the pulmonary arteries. This is a palliative surgery and is associated with complications such as blocked shunt precipitating cardiac arrest, low cardiac output, and pulmonary artery distortion. Historically, there have been several systemic-pulmonary artery shunts. These have

been anastomosis between ascending aorta and RPA (Waterston's) and descending aorta and LPA (Pott's). These shunts have resulted in uncontrolled pulmonary blood flow and gross

**Figure 9.** Tetralogy of Fallot showing a) VSD b) over ride of aorta c) Right ventricular hypertrophy and d) right ventric‐

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Repair of TOF carries excellent results- less than 5% mortality in most centers. Potential complications are right heart failure, residual VSD, residual RVOTO and complete heart block. RVOTO relief varies from simple removal of obstructing muscle bundles to subannular patch to transannular patch. Transannular patch entails incising across the pulmonary valve annulus and results in free pulmonary regurgitation. This can cause right heart failure both acutely and in the long-term. Late pulmonary valve replacement is common in TOF repairs 10-15 years postoperatively. Surgeons are prophylactically placing bicuspid valves in the pulmonary position at the first surgery. [43] This improves immediate outcomes and as well as the long-

Transposition of great arteries is the second ccommonest cyanotic condition. This presents in the neonatal period with the aorta arising from the right ventricle and pulmonary artery from the left ventricle. 50% are born with intact ventricular septum, 25% with VSD and 25% with VSD and PS. Senning's and Mustard's are procedures of historical importance. These are atrial switch procedures wherein the right atrium is directed to drain into the left ventricle and left atrium is directed to right ventricle. The disadvantage of this procedure is that the right

distortion of pulmonary arteries.

ular outflow obstruction.

term results.

**Figure 8.** Types of Truncus Arteriosus

**Figure 9.** Tetralogy of Fallot showing a) VSD b) over ride of aorta c) Right ventricular hypertrophy and d) right ventric‐ ular outflow obstruction.

been anastomosis between ascending aorta and RPA (Waterston's) and descending aorta and LPA (Pott's). These shunts have resulted in uncontrolled pulmonary blood flow and gross distortion of pulmonary arteries.

Repair of TOF carries excellent results- less than 5% mortality in most centers. Potential complications are right heart failure, residual VSD, residual RVOTO and complete heart block. RVOTO relief varies from simple removal of obstructing muscle bundles to subannular patch to transannular patch. Transannular patch entails incising across the pulmonary valve annulus and results in free pulmonary regurgitation. This can cause right heart failure both acutely and in the long-term. Late pulmonary valve replacement is common in TOF repairs 10-15 years postoperatively. Surgeons are prophylactically placing bicuspid valves in the pulmonary position at the first surgery. [43] This improves immediate outcomes and as well as the longterm results.

Transposition of great arteries is the second ccommonest cyanotic condition. This presents in the neonatal period with the aorta arising from the right ventricle and pulmonary artery from the left ventricle. 50% are born with intact ventricular septum, 25% with VSD and 25% with VSD and PS. Senning's and Mustard's are procedures of historical importance. These are atrial switch procedures wherein the right atrium is directed to drain into the left ventricle and left atrium is directed to right ventricle. The disadvantage of this procedure is that the right

**Figure 8.** Types of Truncus Arteriosus

256 Principles and Practice of Cardiothoracic Surgery

ventricle is placed in the systemic circulation. The RV is not designed to sustain the systemic circulation for long periods and many of these patients develop heart failure later and are candidates for heart transplant. Arterial switch operation is the transfer of coronary arteries from aorta to the pulmonary arteries. This results in switching the left ventricle to the systemic circulation.

insufficiency. Long-term complications are neoaortic regurgitation, neo-suprapulmonary

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Total pulmonary venous connection (TAPVC) is a common congenital cardiac condition. Darling's classification divides TAPVC into 4 types- supracardiac, cardiac, infracardiac and mixed. The basic issue is that the pulmonary veins are not attached to the left atrium, form a common pulmonary venous chamber(CPVC) and drain via a communicating vein to some component of the systemic circulation. The commonest is supracardiac- the left vertical vein arising from the CPVC drains to the left innominate vein or less commonly, to the SVC just cranial to the SVC-RA junction. The cardiac variant usually joins the coronary sinus. The infracardiac type has a descending vertical vein draining vertically across the diaphragm to the portal vein or IVC. Mixed types are varying combinations of these. The presentation depends on whether there is obstruction in the pulmonary venous pathway or not. In supra‐ cardiac, the vertical vein may obstruct near the innominate vein or at the level of the ASD- this has to be completely unrestrictive or the child will present with obstructive pulmonary venous symptoms such as breathlessness, and even pulmonary edema. Cardiac type can have obstruction where the CPVC joins the coronary sinus or at the ASD. The infracardiac is the commonest type to present with obstruction as blood has to pass through the liver. This is one of the commonest neonatal cardiac emergencies. Surgery varies depending on the anatomy. Supracardiac TAPVC can be addressed by surgery - creation of anastomosis at the back of the heart between the Left atrium and CPVC. The creation of the anastomosis is dependent on the surgeon's preference- either working through the ASD, lifting the heart to the right, working lateral to the RA, working between the SVC and aorta or Shumacker's repair. Cardiac TAPVC is relatively simple- the coronary sinus is unroofed and pulmonary veins are committed to the LA after partitioning of the atria. The infracardiacTAPVC is again by creation of anastomosis

stenosis and coronary ischemia [45] These occur in less than 10% of patients.

between the LA and CPVC with disconnection of the descending vertical vein.

enteropathy, plastic bronchitis and cardiac failure.

pulmonary veins.

Immediate postoperative complications are low cardiac output, pulmonary hypertensive crisis and pulmonary vein restenosis- either early or late, at the anastomosis or in the individual

Tricuspid atresia is the absence of the tricuspid valve. ASD is mandatory for survival. They can present unrestricted pulmonary blood flow (PBF), in which case they need pulmonary artery band, followed by Glenn followed by Fontan. If the neonate presents with decreased PBF, the first operation is a B-T shunt followed by Glenn and Fontan. At each stage, before the Glenn and Fontan operations, the baby undergoes cardiac catheterization and angiography. The Glenn operation consists of dividing SVC and suturing this to the RPA. This unloads the single ventricle. The Fontan operation consists of a conduit being placed between the IVC and RPA. The single ventricle is thus unloaded of the pulmonary circulation and pumps blood to two circulations in series instead of two ventricles pumping blood to two circulations in parallel. Low cardiac output may occur and long-term complications include protein-losing

There are variations in univentricular physiology. The treatment protocol is similar to the one followed for tricuspid atresia. The common variant of this is hypoplastic left heart syndrome (HLHS) wherein the aorta is hypoplastic and a complex operation called Norwood is per‐

**Figure 10.** Transposition of Great Arteries

Babies with TGA and intact ventricular septum should ideally be operated within 2-3 weeks. The left ventricle loses its ability to sustain the systemic circulation beyond this as it adapts to the lower pulmonary artery pressures. When these patients present late, the options are to proceed with atrial switch which has lesser mortality and rapid two-stage arterial switch. The latter procedure is a staged procedure wherein the PA is banded and B-T shunt is created [44]. This creates the pressure and volume overload on the LV thereby retraining the LV to accept the systemic load. This is a relatively high-risk procedure. Serial echocardiographic assessment aids the surgeon to time the arterial switch once the LV is retrained.

Arterial switch is a worthwhile operation as the long-term results are excellent. Immediate postoperative complications are low cardiac output and myocardial ischemia due to coronary insufficiency. Long-term complications are neoaortic regurgitation, neo-suprapulmonary stenosis and coronary ischemia [45] These occur in less than 10% of patients.

ventricle is placed in the systemic circulation. The RV is not designed to sustain the systemic circulation for long periods and many of these patients develop heart failure later and are candidates for heart transplant. Arterial switch operation is the transfer of coronary arteries from aorta to the pulmonary arteries. This results in switching the left ventricle to the systemic

Babies with TGA and intact ventricular septum should ideally be operated within 2-3 weeks. The left ventricle loses its ability to sustain the systemic circulation beyond this as it adapts to the lower pulmonary artery pressures. When these patients present late, the options are to proceed with atrial switch which has lesser mortality and rapid two-stage arterial switch. The latter procedure is a staged procedure wherein the PA is banded and B-T shunt is created [44]. This creates the pressure and volume overload on the LV thereby retraining the LV to accept the systemic load. This is a relatively high-risk procedure. Serial echocardiographic assessment

Arterial switch is a worthwhile operation as the long-term results are excellent. Immediate postoperative complications are low cardiac output and myocardial ischemia due to coronary

aids the surgeon to time the arterial switch once the LV is retrained.

circulation.

258 Principles and Practice of Cardiothoracic Surgery

**Figure 10.** Transposition of Great Arteries

Total pulmonary venous connection (TAPVC) is a common congenital cardiac condition. Darling's classification divides TAPVC into 4 types- supracardiac, cardiac, infracardiac and mixed. The basic issue is that the pulmonary veins are not attached to the left atrium, form a common pulmonary venous chamber(CPVC) and drain via a communicating vein to some component of the systemic circulation. The commonest is supracardiac- the left vertical vein arising from the CPVC drains to the left innominate vein or less commonly, to the SVC just cranial to the SVC-RA junction. The cardiac variant usually joins the coronary sinus. The infracardiac type has a descending vertical vein draining vertically across the diaphragm to the portal vein or IVC. Mixed types are varying combinations of these. The presentation depends on whether there is obstruction in the pulmonary venous pathway or not. In supra‐ cardiac, the vertical vein may obstruct near the innominate vein or at the level of the ASD- this has to be completely unrestrictive or the child will present with obstructive pulmonary venous symptoms such as breathlessness, and even pulmonary edema. Cardiac type can have obstruction where the CPVC joins the coronary sinus or at the ASD. The infracardiac is the commonest type to present with obstruction as blood has to pass through the liver. This is one of the commonest neonatal cardiac emergencies. Surgery varies depending on the anatomy. Supracardiac TAPVC can be addressed by surgery - creation of anastomosis at the back of the heart between the Left atrium and CPVC. The creation of the anastomosis is dependent on the surgeon's preference- either working through the ASD, lifting the heart to the right, working lateral to the RA, working between the SVC and aorta or Shumacker's repair. Cardiac TAPVC is relatively simple- the coronary sinus is unroofed and pulmonary veins are committed to the LA after partitioning of the atria. The infracardiacTAPVC is again by creation of anastomosis between the LA and CPVC with disconnection of the descending vertical vein.

Immediate postoperative complications are low cardiac output, pulmonary hypertensive crisis and pulmonary vein restenosis- either early or late, at the anastomosis or in the individual pulmonary veins.

Tricuspid atresia is the absence of the tricuspid valve. ASD is mandatory for survival. They can present unrestricted pulmonary blood flow (PBF), in which case they need pulmonary artery band, followed by Glenn followed by Fontan. If the neonate presents with decreased PBF, the first operation is a B-T shunt followed by Glenn and Fontan. At each stage, before the Glenn and Fontan operations, the baby undergoes cardiac catheterization and angiography. The Glenn operation consists of dividing SVC and suturing this to the RPA. This unloads the single ventricle. The Fontan operation consists of a conduit being placed between the IVC and RPA. The single ventricle is thus unloaded of the pulmonary circulation and pumps blood to two circulations in series instead of two ventricles pumping blood to two circulations in parallel. Low cardiac output may occur and long-term complications include protein-losing enteropathy, plastic bronchitis and cardiac failure.

There are variations in univentricular physiology. The treatment protocol is similar to the one followed for tricuspid atresia. The common variant of this is hypoplastic left heart syndrome (HLHS) wherein the aorta is hypoplastic and a complex operation called Norwood is per‐ formed in the neonatal period. The PA is disconnected and reconnected to the systemic circulation to enhance the arch. The pulmonary circulation is provided by a B-T shunt. The patient subsequently undergoes Glenn and Fontan procedures.

Corrected transposition of great arteries (CCTGA) or l-TGA consists of atrio-ventricular and ventriculo-arterial discordance. The child may present with intact ventricular septum. The disadvantage lies in the fact that the RV is in the systemic circulation and will fail over a period of time. The child may present with VSD and with or without pulmonary stenosis. There are two approaches- anatomic and physiologic repairs. The physiologic approach consists of addressing the various lesions- VSD and PS thereby leaving the RV in the systemic circulation with doubtful long-term outcomes. The anatomic repair consists of double switch. The procedure consists of performing atrial switch and arterial switch. This eventually results in the LV being in the systemic circulation. If there is a VSD, this is surgically closed. The chances of complete heart block requiring a pacemaker is high as the A-V node and Bundle of His are in an abnormal position. If there is a PS, the procedure is an atrial switch-Rastelli- the RV is connected to the PA via conduit. These are complex procedures carrying significant morbidity and mortality [46] These children present with left A-V valve regurgitation as well. This is the tricuspid valve functioning as the systemic valve. A simplified approach to this condition is to perform Glenn followed by Fontan procedure if they present with VSD with significant PS. This carries lesser mortality than the above procedures. However, the Fontan circulation is an imperfect state and has its own disadvantages.

#### **18.3. Congenital lesions of valves, aorta and coronary arteries**

The four valves are prone to various congenital anomalies:

**1.** Tricuspid valve- Ebstein's anomaly is the commonest congenital anomaly of the TV. There is apical displacement of the septal and postero-inferior leaflets with a sail-like anterior leaflet. This results in severe TR. The RA is dilated with RV dilatation and dysfunction. This condition is associated with accessory conduction pathways which predispose to supraventricular arrhythmias. This is diagnosed from the presence of delta waves in the ECG. Criteria for surgery are presence of dyspnoea NYHA III-IV, cardiomegaly (CTR ratio > 0.65) and cyanosis in the presence of ASD. LV dysfunction is noted when cases present late due to RV dysfunction causing LV to be affected by the phenomenon-of ventricular interdependence. Neonatal Ebstein's is a particular difficult subset to treat and the Starne's operation has been described- elective closure of the tricuspid valve and B-T shunt followed by staging to Glenn and Fontan.(figure 10).

replaced. Bioprosthetic valves are preferred in the tricuspid position as the circulation is sluggish compared to the left heart and mechanical valves in this position are prone to clotting and there have been reports of sudden death. Bioprosthetic valves require reoperation as they deteriorate over a period but reoperations are not associated with increased mortality.

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Other causes of congenital TR are due congenital dysplastic leaflets. Various standard valve repair strategies are employed such as artificial Chordae, closure of clefts and commissures,

**2.** Pulmonary valve- Congenital anomalies of the PV present as pulmonary stenosis. Intervention is indicated when the gradient > 50 mm Hg. This is usually performed by the interventional cardiologist. Most cases are amenable to balloon valvuloplasty. Surgery is only indicated if there is supra-annular narrowing, annular hypoplasia or dysplastic leaflets. Surgical relief is by open pulmonary valvotomy with or without transannular patch. Patients can present with isolated infundibular obstruction. This requires open heart surgery- either resection of RVOT muscle bundles and if necessary, subannular

When patients present with free pulmonary regurgitation following TOF repair, reoperation is indicated if children are symptomatic, the RV dilates or the patient presents with ventricular tachycardia. Surgical options include pulmonary valve replacement with pulmonary or aortic

and leaflet enhancements with commissural annuloplasty or ring annuloplasty.

**Figure 11.** Ebsteins anomaly of tricuspid valve showing atrialised RV and displaced tricuspid leaflets.

patch.

Children and adults with Ebstein'sanomaly require tricuspid valve repair. There are various techniques described such as Danielson's [47], Carpentier's, Cone [48] and Stanford [49] technique and variations on these with proponents for each. The repair aims to achieve tricuspid competence, without compromising RV cavity if possible. Some techniques aim to obliterate the atrialised RV and others ignore it. Complications include severe RV dysfunction, arrhythmias, low cardiac output. Glenn is performed by the surgeon if he feels the RV will not be able to cope. If tricuspid regurgitation is significant, the tricuspid valve is electively

formed in the neonatal period. The PA is disconnected and reconnected to the systemic circulation to enhance the arch. The pulmonary circulation is provided by a B-T shunt. The

Corrected transposition of great arteries (CCTGA) or l-TGA consists of atrio-ventricular and ventriculo-arterial discordance. The child may present with intact ventricular septum. The disadvantage lies in the fact that the RV is in the systemic circulation and will fail over a period of time. The child may present with VSD and with or without pulmonary stenosis. There are two approaches- anatomic and physiologic repairs. The physiologic approach consists of addressing the various lesions- VSD and PS thereby leaving the RV in the systemic circulation with doubtful long-term outcomes. The anatomic repair consists of double switch. The procedure consists of performing atrial switch and arterial switch. This eventually results in the LV being in the systemic circulation. If there is a VSD, this is surgically closed. The chances of complete heart block requiring a pacemaker is high as the A-V node and Bundle of His are in an abnormal position. If there is a PS, the procedure is an atrial switch-Rastelli- the RV is connected to the PA via conduit. These are complex procedures carrying significant morbidity and mortality [46] These children present with left A-V valve regurgitation as well. This is the tricuspid valve functioning as the systemic valve. A simplified approach to this condition is to perform Glenn followed by Fontan procedure if they present with VSD with significant PS. This carries lesser mortality than the above procedures. However, the Fontan circulation is an

**1.** Tricuspid valve- Ebstein's anomaly is the commonest congenital anomaly of the TV. There is apical displacement of the septal and postero-inferior leaflets with a sail-like anterior leaflet. This results in severe TR. The RA is dilated with RV dilatation and dysfunction. This condition is associated with accessory conduction pathways which predispose to supraventricular arrhythmias. This is diagnosed from the presence of delta waves in the ECG. Criteria for surgery are presence of dyspnoea NYHA III-IV, cardiomegaly (CTR ratio > 0.65) and cyanosis in the presence of ASD. LV dysfunction is noted when cases present late due to RV dysfunction causing LV to be affected by the phenomenon-of ventricular interdependence. Neonatal Ebstein's is a particular difficult subset to treat and the Starne's operation has been described- elective closure of the tricuspid valve and B-T shunt

Children and adults with Ebstein'sanomaly require tricuspid valve repair. There are various techniques described such as Danielson's [47], Carpentier's, Cone [48] and Stanford [49] technique and variations on these with proponents for each. The repair aims to achieve tricuspid competence, without compromising RV cavity if possible. Some techniques aim to obliterate the atrialised RV and others ignore it. Complications include severe RV dysfunction, arrhythmias, low cardiac output. Glenn is performed by the surgeon if he feels the RV will not be able to cope. If tricuspid regurgitation is significant, the tricuspid valve is electively

patient subsequently undergoes Glenn and Fontan procedures.

260 Principles and Practice of Cardiothoracic Surgery

imperfect state and has its own disadvantages.

**18.3. Congenital lesions of valves, aorta and coronary arteries**

The four valves are prone to various congenital anomalies:

followed by staging to Glenn and Fontan.(figure 10).

**Figure 11.** Ebsteins anomaly of tricuspid valve showing atrialised RV and displaced tricuspid leaflets.

replaced. Bioprosthetic valves are preferred in the tricuspid position as the circulation is sluggish compared to the left heart and mechanical valves in this position are prone to clotting and there have been reports of sudden death. Bioprosthetic valves require reoperation as they deteriorate over a period but reoperations are not associated with increased mortality.

Other causes of congenital TR are due congenital dysplastic leaflets. Various standard valve repair strategies are employed such as artificial Chordae, closure of clefts and commissures, and leaflet enhancements with commissural annuloplasty or ring annuloplasty.

**2.** Pulmonary valve- Congenital anomalies of the PV present as pulmonary stenosis. Intervention is indicated when the gradient > 50 mm Hg. This is usually performed by the interventional cardiologist. Most cases are amenable to balloon valvuloplasty. Surgery is only indicated if there is supra-annular narrowing, annular hypoplasia or dysplastic leaflets. Surgical relief is by open pulmonary valvotomy with or without transannular patch. Patients can present with isolated infundibular obstruction. This requires open heart surgery- either resection of RVOT muscle bundles and if necessary, subannular patch.

When patients present with free pulmonary regurgitation following TOF repair, reoperation is indicated if children are symptomatic, the RV dilates or the patient presents with ventricular tachycardia. Surgical options include pulmonary valve replacement with pulmonary or aortic homografts, bovine jugular vein conduits and bioprosthetic valves. These valves are of limited durability and will require re-replacment. Percutaneous deployment of pulmonary valves has clinically employed with limited success.

whenever possible and hence, further surgical options are to replace ascending aorta and repair

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Coronary artery anomalies are uncommon and include anomalous origin of the left coronary artery from pulmonary artery (ALCAPA), coronary arterio-venous fistula and coronary artery aneurysms. ALCAPA characteristically presents with severe LV dysfunction and mitral regurgitation. The problems are two-fold: connection of the left coronary artery to the PA which results in myocardial ischemia and the left-to-right shunt ensuing. Ideal procedure is urgent surgery and re-implantation of the left coronary to the aorta. Takeuchi repair or its modifications to baffle the left coronary to the aorta has also been described. Less than ideal is to tie off the left main and leave the patient on a single coronary. Adults have been managed

These are rare conditions. Congenital tracheal stenosis consists of localised or long-segment stenosis of trachea due to presence of complete tracheal rings. These are associated with cardiac lesions such as TOF. The patients present with stridor. Surgery is the treatment of choice. These include slide plasty,resection and end-to-end anastomosis, homograft replacement and patch

The two common vascular anomalies that present are double aortic arch and left pulmonary artery sling. Double aortic arch [50] is due to the persistence of both right and left dorsal aortic arches. Symptoms are related to the compression of the trachea and esophagus by the relevant vascular structures. Surgery for double arch is via left thoracotomy, division of the PDA/ ligamentumarteriosum and surgical division of the smaller arch distal to the corresponding subclavian artery. LPA sling is associated in 50-65% of cases with tracheal stenosis due to complete rings. Surgery is by reimplantation of the LPA onto the MPA either via left thora‐

Children who grow into adults with congenital heart disease come under this category.

Left-to-right shunts: Atrial septal defect of all types can present in adulthood and are usually operable. A small percentage present with irreversible pulmonary hypertension. Operations on adults provide a survival benefit upto 25 years of age, but beyond that, the main indication is improving quality of life, prevention of paradoxical embolism and most importantly,

Ventricular septal defect rarely present in adulthood as they are operable only as children. The only odd case maybe the rare ones with large VSD that have not become Eisenmenger's and the one who present with aortic valve prolapse or along with aortic regurgitation and/ or ruptured sinus of Valsalva aneurysm. The latter characteristically present in middle age. The other common subset is those adults who present with VSD and RVOT obstruction (double chamber right ventricle or adults with closing VSD and acquired RVOT obstruction-gazzuli‐

the AV or root-preserving surgery.

by ligation of left main and coronary artery bypass grafting.

**18.4. Congenital tracheal anomalies and vascular rings**

plasty of trachea simultaneous with the cardiac repair.

cotomy or median sternotomy on cardiopulmonary bypass [51]

**18.5. Adult congenital cardiac surgery**

prevent the onset of atrial fibrillation.

zation.)


Children, particularly those with Marfan's and other connective tissue disorder, can present with aneuysmal dilatation of the aorta. The indications for surgery are similar to those for adults with the aim being to prevent rupture. Surgical options include replacement of the ascending aorta with an interposition graft and Bentall procedure wherein the whole aortic root is replaced with composite graft including a mechanical valve and reimplantation of the coronary arteries if there is associated AR. Current concepts are to preserve the native valve whenever possible and hence, further surgical options are to replace ascending aorta and repair the AV or root-preserving surgery.

Coronary artery anomalies are uncommon and include anomalous origin of the left coronary artery from pulmonary artery (ALCAPA), coronary arterio-venous fistula and coronary artery aneurysms. ALCAPA characteristically presents with severe LV dysfunction and mitral regurgitation. The problems are two-fold: connection of the left coronary artery to the PA which results in myocardial ischemia and the left-to-right shunt ensuing. Ideal procedure is urgent surgery and re-implantation of the left coronary to the aorta. Takeuchi repair or its modifications to baffle the left coronary to the aorta has also been described. Less than ideal is to tie off the left main and leave the patient on a single coronary. Adults have been managed by ligation of left main and coronary artery bypass grafting.

#### **18.4. Congenital tracheal anomalies and vascular rings**

homografts, bovine jugular vein conduits and bioprosthetic valves. These valves are of limited durability and will require re-replacment. Percutaneous deployment of pulmonary valves has

**2.** Mitral valve- Congenital anomalies MV can be either mitral stenosis (MS) or mitral regurgitation (MR). Variants of MS include commissural fusion, parachute MV (single papillary muscle), hammock MV and variations in anomalies of the annulus, leaflets, chordae and papillary muscles. Congenital MR is due to the following mechanisms: Carpentier's classification- type 1-normal leaflets, type 2-leaflet prolapsed, type 3-leaflet restriction. If there is perforation in the leaflet, this is closed with a patch. If the annulus is dilated, this is reduced either by suture annuloplasty, commissural annuloplasty or ring annuloplasty. In leaflet prolapsed, the use of artificial chordate is gaining popularity. Contrary to the belief that this is contraindicated in children as they may outgrow their chordae, this has not been found to be the case as corresponding growth of the papillary muscle compensates. Chordal transposition or chordal shortening are described with good results. Leaflet restriction is addressed by releasing tethering secondary and tertiary chordae and leaflet enhancement with pericardial patch. Repair is always preferable in children at the expense of residual MS/MR as mitral valve replacement carries high risk in children due to their small annulus. Bioprosthetic valves degenerate rapidly due to the accelerated calcium metabolism of adolescence and mechanical valves require anticoa‐ gulation which is difficult to manage in children. Small valves are quickly outgrown by

**3.** Aortic valve- Commonest AV lesion is congenital bicuspid aortic valve. This usually presents with stenosis. The optimal treatment when obstruction is significant is balloon valvuloplasty. This is associated with greater recurrence but delaying surgery is always preferable till the child is bigger and the annulus is larger. Congenital AS may present as unicuspid valve as well. Open aortic valvotomy is a simple procedure wherein the surgeon splits the valve judiciously at the commissures. Bicuspid valve can present with AR as well. Repair is still preferable and various valve preservation techniques are described. Residual AR is preferable to aortic valve replacement in infants and children. AVR in children varies from mechanical valve replacement in older children, Ross procedure wherein the patients PV is placed in the aortic position and conduit placed in the pulmonary position and aortic homograft root replacement. Anticoagulation is not required for Ross and homografts with the former carrying the advantage of increased durability of the aortic autograft. Mechanical valves, particularly if small, are fraught with

Children, particularly those with Marfan's and other connective tissue disorder, can present with aneuysmal dilatation of the aorta. The indications for surgery are similar to those for adults with the aim being to prevent rupture. Surgical options include replacement of the ascending aorta with an interposition graft and Bentall procedure wherein the whole aortic root is replaced with composite graft including a mechanical valve and reimplantation of the coronary arteries if there is associated AR. Current concepts are to preserve the native valve

clinically employed with limited success.

262 Principles and Practice of Cardiothoracic Surgery

the child.

problems particularly outgrowth.

These are rare conditions. Congenital tracheal stenosis consists of localised or long-segment stenosis of trachea due to presence of complete tracheal rings. These are associated with cardiac lesions such as TOF. The patients present with stridor. Surgery is the treatment of choice. These include slide plasty,resection and end-to-end anastomosis, homograft replacement and patch plasty of trachea simultaneous with the cardiac repair.

The two common vascular anomalies that present are double aortic arch and left pulmonary artery sling. Double aortic arch [50] is due to the persistence of both right and left dorsal aortic arches. Symptoms are related to the compression of the trachea and esophagus by the relevant vascular structures. Surgery for double arch is via left thoracotomy, division of the PDA/ ligamentumarteriosum and surgical division of the smaller arch distal to the corresponding subclavian artery. LPA sling is associated in 50-65% of cases with tracheal stenosis due to complete rings. Surgery is by reimplantation of the LPA onto the MPA either via left thora‐ cotomy or median sternotomy on cardiopulmonary bypass [51]

#### **18.5. Adult congenital cardiac surgery**

Children who grow into adults with congenital heart disease come under this category.

Left-to-right shunts: Atrial septal defect of all types can present in adulthood and are usually operable. A small percentage present with irreversible pulmonary hypertension. Operations on adults provide a survival benefit upto 25 years of age, but beyond that, the main indication is improving quality of life, prevention of paradoxical embolism and most importantly, prevent the onset of atrial fibrillation.

Ventricular septal defect rarely present in adulthood as they are operable only as children. The only odd case maybe the rare ones with large VSD that have not become Eisenmenger's and the one who present with aortic valve prolapse or along with aortic regurgitation and/ or ruptured sinus of Valsalva aneurysm. The latter characteristically present in middle age. The other common subset is those adults who present with VSD and RVOT obstruction (double chamber right ventricle or adults with closing VSD and acquired RVOT obstruction-gazzuli‐ zation.)

Adults do occasionally present with PDA- the large ones are rarely still operable and the small ones can be occluded by the interventional cardiologist. Surgery in PDA with pulmonary hypertension is high-risk as they are fragile and prone to catastrophic tears during surgerythey may be calcified. Surgery is more complex- requiring cardiopulmonary bypass.

**19. Arryhtmias, pacemakers and defibrillators**

**20. Future of congenital cardiac surgery**

will work together.

with substandard alternatives.

surgery.

The congenital population is prone to postoperative complete heart block and even nodal arrhythmias are not tolerated by the population with single ventricle physiology. These children will require to be under the care of the electrophysiologist. They will need lifelong pacemaker changes and lead changes. Arrhythmias are common such as atrial fibrillation and those related to accessory bundle pathways. Children with dilated RV/LV are prone to malignant ventricular arrhythmias such as ventricular tachycardia and ventricular fibrillation. These require monitoring and insertion of AICD (automatic internal cardioverter-defibrilla‐ tor). Patients with chronic atrial fibrillation may benefit from the Maze procedure (antiar‐ rhythmic surgery). This procedure may involve either right atrium or left atrium or both.

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**1. Rise of interventional cardiology:** The interventional cardiologists have taken over many of the procedures formerly done exclusively by the surgeons. These include atrial septal defect (ostium secundum), and patent ductus arteriosus closure. Certain VSD's are being closed by the cardiologists. Open pulmonary valvotomy is a procedure of historical importance and open aortic valvotomy is rarely undertaken as a primary procedure. Procedures which will be undertaken with increasing aggressiveness by the interven‐ tionalist include ductal stenting, and RVOT stenting as a substitute for B-T shunt, and percutaneous pulmonary valve replacement. Percutaneous maze procedures, percutane‐ ous mitral valve repairs, and percutaneous completion Fontan are on the anvil. Lesions such as aortopulmonary window, aorto-cameral tunnel and coronary a-v fistulae are amenable to interventional strategies. This will result in a change in the spectrum of surgeries done- surgeries will become more complex and the number of simple surgeries will dwindle. Hybrid procedures will rise wherein the cardiologist and cardiac surgeon

**2. Fetal echocardiography:** Antenatal diagnosis of congenital cardiac conditions is possible at 18-20 weeks of gestational age. This will empower parents with the option of medical termination of pregnancy. This will reduce the number of children requiring heart

**3. Robotic cardiac surgery/ thoracoscopic surgery:** Certain operations may be performed by the surgeon sitting at the console or maybe even in another part of the world utilising computer-controlled robotic arms. Thoracoscopic surgery may be an alternative for PDA.

**4. Disappearance of valve replacements:** Surgeons will become increasingly skilled at preserving the patient's own valve by mastering the skill of repairing rather than replacing

Coarctation is not uncommon in presentation as an adult, either as a primary coarctation or re-coarctation. Surgery is high-risk, particularly with tight coarctation with multiple collater‐ als. Entry into the chest is associated with significant bleeding and very often, the coarct segment has to be excised and replaced with an interposition graft. The aortic tissue is usually friable and is prone to tear. A bypass graft from the left subclavian artery to the descending aorta may then be preferable. Recoarctation is better dealt with balloon plasty and stenting. Adults with coarctation may be managed with covered stents.

Tetralogy of Fallot may present in adulthood. They are amenable to corrective surgery provided criteria are met such as adequacy of pulmonary arteries and there are no significant collaterals. They may need preoperative embolization of collaterals and intraoperative RV-PA conduit as they may not tolerate free pulmonary regurgitation in the event of transannular patch. The children who underwent repair as children may present in adulthood with RV dysfunction due to free PR. They require redo sternotomy and insertion of RV-PA conduit. A subset of these patients presents as adults with aortic regurgitation and/or ascending aortic aneurysm and require AVR with or without ascending aorta replacement.

Patients may present de novo with RVOT obstruction at various levels. These are amenable to surgery or intervention based on various criteria.

Children who underwent Senning's or Mustard's procedure from transposition of great arteries (TGA) present in adulthood with residual defects such as baffle leaks or with cardiac failure as the RV in the systemic position is prone to failure. These patients require heart transplant or conversion to arterial switch following PA banding to retrain the LV. These are high-risk procedures.

Children with single ventricle physiology present in adulthood requiring Fontan procedure. Some have had atriopulmonary Fontan and require conversion to an extracardiac Fontan if the former surgery fails.

Ebstein's anomaly, cor triatriatum sinister (membrane in the left atrium obstructing pulmonary veins), ALCAPA and TAPVC with unrestricted ASD are conditions with which patients may present as adults for surgery. Congenital corrected transposition of great arteries, with VSD and PS may also present late.

Children who have undergone arterial switch as infants present as adults with coronary issues, neo-pulmonarysupravalvular stenosis, and neoaortic regurgitation. These patients require stenting of their coronary artery obstructions, coronary artery bypass grafting, patch plasty of supravalvular obstruction and replacement of the aortic valve.
