Introduction

Cardiac surgery is a quite young specialty, only dating back about 80 years. The development of surgery for congenital heart diseases (CHDs) is in fact the story of the development of cardiac surgery in general, as CHDs were historically the first cardiac diseases to be surgically treated.

History of surgery for congenital heart diseases

The history of surgery for CHDs began on 26 August 1938, when Robert Gross performed the first successful ligation of a patent ductus arteriosus (PDA) in a 7-year-old girl at the Children’s Hospital of Boston (Gross & Hubbard 1939).

On 19 October 1944, Clarence Crafoord and G. Nylin in Stockholm, Sweden, successfully repaired a coarctation of the aorta (CoA) with resection and end-to-end anastomosis (Crafoord & Nylin 1945).

After Dr Helen Taussig, Paediatric Cardiologist at Johns Hopkins Hospital, Baltimore, observed that children with Tetralogy of Fallot (TOF) and a PDA did better until the PDA closed off, she convinced Alfred Blalock (a surgeon at the same hospital) to construct a ‘ductus’. Blalock (with his surgical assistant Vivien Thomas) had performed in the laboratory many anastomoses of the subclavian artery to the pulmonary artery for his research on pulmonary arterial hypertension in an animal model. Thus, on 29 November 1944, Blalock anastomosed the left subclavian artery to the left pulmonary artery, in a 15-month-old girl weighing only 10 pounds, with hypoxic spells (Blalock & Taussig 1945). Though the postoperative course of the patient was challenging and she died after six months, the so-called ‘classic Blalock-Taussig shunt’ has since been used worldwide and has offered considerable palliation and quality of life to ‘blue’ (cyanosed) babies.

These efforts to offer palliation to cyanotic patients led Willis J. Potts, on 16 September 1946, at the Children’s Memorial Hospital of Chicago, to anastomose the descending aorta to the left pulmonary artery in a side-to-side fashion (the ‘Potts shunt’) (Potts, Smith & Gibson 1946).

In an attempt to offer palliation to children with transposition of the great arteries (TGA) by better intracardiac mixing of oxygenated and non-oxygenated blood, A. Blalock and C.R. Hanlon performed the first closed atrial septectomy (that is the surgical creation of an atrial septal defect), on 24 May 1948, at Johns Hopkins Hospital (Blalock & Hanlon 1950).

On 11 July 1951, W.H. Muller and J.F. Dammann Jr, at the University of California in Los Angeles, performed a pulmonary artery banding (PAB) in a 5-month-old infant with an atrioventricular septal defect and a large left-to-right (L-to-R) shunt (Muller & Dammann 1952). PAB offered good palliation. and protected the pulmonary vascular bed in CHDs with large L-to-R shunts, until successful surgery could be carried out at a later age.

The first repair of an intracardiac defect was performed on 15 April 1952, when Robert Gross and his colleagues at the Boston Children’s Hospital, closed an atrial septal defect (ASD) with the aid of an ‘atrial well’. This ingenious technique consisted of sewing a soft, plastic, funnel-like device onto the wall of the right atrium, which was then entered. The surgeon was able to digitally explore the atrial structures and perform a surgical repair working beneath the layer of blood in the well. This method precluded direct vision but in skilled hands it led to remarkable results (Gross et al. 1953).

The first successful open-heart surgery in the world was performed on 2 September 1952, by John F. Lewis and Mansur Taufic at the University of Minnesota. They closed an ASD in a 5-year-old girl under direct vision, using moderate surface-induced hypothermia (26°C) and 5.5 minutes of circulatory arrest with caval inflow occlusion (Lewis & Taufic 1953). The child was discharged 11 days after surgery.

The same year, on 21 October, the first open pulmonary valvotomy was performed by F.D. Dodrill with the aid of a right heart bypass at Detroit (Gibbon 1954).

Less than a year later, the first successful open-heart procedure with the use of the heart-lung machine was performed, completely changing the route of cardiac surgery. On 6 May 1953, John Heysham Gibbon Jr, at the Jefferson University Medical Centre in Philadelphia, closed a large secundum ASD in an 18-year-old woman using total cardiopulmonary bypass for 26 minutes (Dodrill 1954). Though Dr Gibbon abandoned his method soon after (disappointed by subsequent failures), he is still seen as the architect of extracorporeal circulatory support (ECCS).

In 1955, John Kirklin, at the Mayo Clinic, reported the first series of patients (8 cases – 4 survivors) who were treated with the use of cardiopulmonary bypass using a mechanical ‘heart-lung machine’ (Kirklin et al. 1955).

In the 1950s, babies with TGA were palliated with either a Blalock-Hanlon atrial septectomy or one of the partial venous switch operations pioneered by Baffes, Albert and others, with a substantial mortality rate for any of these procedures. In the mid-1950s, William Thornton Mustard, from the Hospital for Sick Children in Toronto, Canada, attempted a partial arterial switch operation with relocation of one coronary artery, but none of his patients survived (Freedom, Lock & Bricker 2000).

In 1959, Ake Senning from Stockholm, Sweden, incised and performed a complete venous switch at the atrial level, using atrial wall flaps only, for surgical treatment of TGA. His technique achieved a physiologic, not anatomic, repair, but most surgeons in that era were unable to reproduce it with acceptable surgical mortality (Senning 1959).

Then, in May 1963, Mustard of Toronto, Canada, performed his first inflow atrial switch procedure using autologous pericardium, resulting in physiologic repair of TGA (Mustard 1964). Mustard’s technique was much simpler than Senning’s and reproducible, and it was therefore quickly adopted worldwide. However, it could not be performed in babies’ younger than 1 year of age, so they required some type of palliation to survive to the age at which the Mustard procedure could be performed. In many centres, the Blalock-Hanlon procedure was used until 1966, when Rashkind and Miller introduced the transcatheter balloon atrial septostomy (Rashkind & Miller 1966).

In 1959, Charles Drew of London introduced the technique of deep hypothermic (approximately 15°C) circulatory arrest (Drew & Anderson 1959). This was not widely adopted at the time but was reintroduced by Dillard et al. (1967) at the University of Washington and by Brian Barratt-Boyes in Auckland, New Zealand, in the middle and late 1960s, providing the ability to perform primary repair of many CHDs in neonates and young infants (Barratt-Boyes & Neutze 1971).

In the 1960s, David J. Waterston in the UK (Waterston 1962) and Denton Cooley in the USA (Cooley & Hallman 1966) incised independently and performed the ‘Waterston-Cooley shunt’, which is an intrapericardial side-to-side anastomosis of the ascending aorta to the adjacent right pulmonary artery through a right thoracotomy or sternotomy. These two shunts were abandoned after some years of employment because of the high incidence of subsequent pulmonary hypertension and congestive heart failure, the preferential blood flow to one lung with kinking and distortion of the pulmonary artery, and technical difficulties with takedown at the final repair.

In 1962, Klinner and colleagues from Germany originally described a modification of the Blalock-Taussig (B-T) shunt that is the interposition of a Polytetrafluoroethylene graft between the subclavian artery and the pulmonary artery (Klinner, Pasini & Schaudig 1962). The ‘modified B-T shunt’ (MBTS) was subsequently detailed by A.B. Gazzaniga of Ann Arbor, Michigan (Gazzaniga et al. 1976) and Marc R. de Leval of Great Ormond Street Hospital, London (De Leval et al. 1981) and is currently the most commonly used systemic-pulmonary arterial shunt.

On 25 February 1958, W.W.L. Glenn of Yale University, performed the first ‘partial right heart bypass’ in a 7-year-old boy with single ventricle and pulmonary stenosis. In this ‘classic’ superior cavopulmonary shunt (‘Glenn shunt’), the superior vena cava (SVC) was taken off the right atrium (RA) and anastomosed end-to-end to the right pulmonary artery (RPA), which was disconnected from the left pulmonary artery (LPA) (Glenn 1958). The Glenn shunt was subsequently modified to the ‘bidirectional Glenn shunt’, where the SVC is anastomosed to the RPA in continuity to the LPA, thus perfusing both lungs.

A decade later, on 25 April 1968, Francis Fontan and E. Baudet at Bordeaux, France, conceived and effectively carried out the ‘total right heart bypass’ in three patients with tricuspid atresia (Fontan & Baudet 1971). The ‘Fontan procedure’ has provided long-term palliation for patients with heart malformations not amenable to biventricular repair. It is the procedure which has been modified most to make the ‘Fontan circulation’ more energy-efficient. Thus, in many centres, a total cavopulmonary connection, lateral tunnel or extra-cardiac Fontan are now routinely used. Several manoeuvres have also been introduced to reduce Fontan mortality, including staging with a bidirectional cavopulmonary shunt with or without atrial fenestration at the time of the Fontan (Freedom, Lock & Bricker 2000).

Two decades after the failed attempts at an anatomic repair of a TGA, this was finally accomplished on 8 May 1975, by Adib Jatene in Sao Paolo, Brazil (Jatene et al. 1976). By the late 1970s, the ‘arterial switch operation’ had become the procedure of choice for most patients with TGA. Manoeuvres were introduced to prepare the left ventricle of the patient with transposition and intact ventricular septum for the arterial switch when the babies presented after the first month of life.

In 1981, William Imon Norwood Jr and his colleagues from Boston Children’s Hospital reported the first successful use of the ‘Norwood procedure’, which is a three-stage surgical procedure for general palliation of patients with hypoplastic left heart syndrome and single ventricle (Norwood et al. 1981). Stage 1 involves atrial septectomy, transection of the distal main pulmonary artery, connection of the proximal main pulmonary artery to the hypoplastic aortic arch with simultaneous repair of the hypoplastic ascending aorta and aortic arch with the aid of a patch, and creation of an aortopulmonary shunt (modified B-T shunt) between a brachiocephalic vessel to the distal main pulmonary artery to provide pulmonary blood flow. Stage 2 is removal of the aortopulmonary shunt and creation of a bidirectional superior cavo-pulmonary connection (or Glenn shunt). Stage 3 is the complete separation of the systemic from the pulmonary circulation with the creation of total cavo-pulmonary connection (or Fontan procedure). ‘Norwood procedure – stage I’ has numerous modifications, with the most important being the ‘RV-to-PA shunt’, instead of the MBTS, introduced by Shunji Sano, from Okayama University, Japan, in 2003 (Sano et al. 2003).

Median sternotomy

Procedure

The patient is placed in a supine position. A support is placed under their back, vertical to the spine, at the height of the nipples, to elevate the chest and the heart. A vertical skin incision is made with a scalpel bearing a No 22 (No 15 for children) blade, starting from just below the sternal notch, or at the midpoint between the angle of Louis and the sternal notch, and ending a few centimetres below the xiphoid process, or at the corner of it. This is an important cosmetic consideration, since the major disadvantage of the standard median sternotomy incision is the visibility of its upper corner.

After the skin, the subcutaneous tissues are incised with diathermy down to the sternum. The first assistant lifts, with a venous retractor, the upper corner of the sternotomy and the surgeon divides the interclavicular ligament at the sternal notch with diathermy. With a small dissector and the finger, the surgeon bluntly dissects behind the sternal notch with caution, because of the risk of accidental injury to adjacent vessels. Then, the xiphoid process is divided and its two halves are freed from the underlying tissues with diathermy.

Using a Roberts forceps, the soft retrosternal tissues are blindly and carefully dissected up to the manubrium, if possible, to create a retrosternal passage and facilitate the sternotomy. Care should be taken not to cause arrhythmia with this retrosternal dissection. The division of the sternum should be made at its midline, after detecting the lateral margin of the bone by dipping the thumb and the index finger into the intercostal spaces. Off-midline sternotomy may cause the closure sutures/wires to cut through the thinner half of the bone, which may cause unstable sternum and wound infection. The sternal periosteum is then divided with diathermy, and bleeding points are cauterised with care taken not to strip the periosteum, as this could cause difficulties with healing later.

The sternum can then be divided, either from top to bottom or bottom to top, according to personal preference, with a standard pneumatic sternal saw (sternotomy), using as a guide the previous division of the sternal periosteum. A sternal retractor is placed into the incision inferiorly, to decrease the risk of damage to the brachial plexus. The thymus is partially (the right lobe) or totally excised, depending on the type of cardiac procedure being undertaken. Care should be taken to preserve the vascularity of the left remaining lobe of the thymus, otherwise at the end of the procedure the remaining thymus will become either ischaemic, or congestive, and should be removed. In adults, the thymus is simply divided at its isthmus between two Roberts clamps and its two stumps are grossly ligated. The left innominate vein is dissected and slinged with a vessel loop. The pericardium is opened (either longitudinally or, if an autologous pericardial patch may be used, in a ‘trapdoor’ fashion) and suspended.

Suspension of pericardium

Redo sternotomy

Reopening an old sternal incision (redo sternotomy) is very common, as heart reoperations have become a routine, particularly for CHDs. Though more complicated than the initial sternotomy, it is a safe procedure if it is carefully planned and performed. Planning begins with the preoperative imaging studies, i.e. chest X-ray, angiography or magnetic resonance/computed tomography (MRI/CT) scan, which reveal the distance between the posterior sternal plate and the heart and great vessels.

The sternal wires, if there, are helpful markers on a lateral angiogram. The surgical team should also have information about the patency and size of the femoral and iliac vessels either from the preoperative catheterisation or from femoral ultrasound study. Clinical examination of both groins for previous cut down incisions, and careful palpation of the femoral pulses, is mandatory. At least one groin should be prepped into the surgical field. Injury to the right heart can be managed easily with urgent cannulation of the femoral artery and placement of a pump sucker in the injured structure, but injury to the aorta is a serious problem. If the aorta is close to the posterior plate of the sternum, cannulation of the femoral artery and vein is required before sternotomy.

If a right heart structure is very close to the sternum, then at least the femoral artery should be cannulated before sternotomy and the cannula should be advanced to the level of the RA to allow good decompression of the right heart. If the femoral arteries are occluded bilaterally or they are too small, alternatives are the axillary artery (usually for adults), or the external iliac artery via a retroperitoneal approach (for children), or the innominate artery. The skin incision should be extended cephalad. The previous skin scar is usually excised and the sternal wires are cut but not removed, as they will be the markers of the posterior plate of the sternum while cutting with the oscillating saw. The xiphoid process is divided and the linea alba is opened to allow a plane to be created behind the lower part of the sternum. With Rake™ retractors, the lower part of the sternum is elevated off the heart, providing a counter-pressure to the oscillating sternal saw.

The bone is cut through in short segments sequentially up to, but not through, the posterior sternal plate, which is then divided with heavy scissors while visualising the space behind the sternum. Diathermy is used again to create a space between the posterior sternum and the suprasternal notch towards the neck. Repeating this process again and again, the sternum is finally completely divided. The interclavicular ligament is now divided, if it has not previously been divided. The dissection with diathermy continues below the two sternal parts and the sternal retractor is placed, but not fully opened.

Closure of sternotomy

The sternum can be closed with absorbable sutures (Vicryl No 0, or 1, or 2), or non-absorbable sutures (ethibond), or sternal wires. The subcutaneous tissues are sutured in two layers with continuous absorbable sutures (Vicryl No 3-0). The skin is closed with Vicryl No 4-0 or Polydioxanone (commonly known as PDS) No 4-0 sutures.

Thoracotomy

The preferred incision is the posterolateral thoracotomy because it offers the best exposure for coarctation of the aorta (CoA) repair and patent ductus arteriosus (PDA) ligation. The patient is placed in a full right lateral decubitus position and secured with a strap over their upper (left) hip; a bridge is placed under the contralateral-dependent hemithorax, at the height of the intercostal space (ICS) chosen for the thoracotomy, to widen the intercostal space and facilitate entry to the hemithorax. The guiding anatomic points for the skin incision are anteriorly the nipple of the left breast, and posteriorly the spine and upper corner of the scapula. The shape of the incision is grossly an ‘S’. The Lattismus dorsi is divided, the serratus anterior muscle can be preserved; the trapezius muscle is only partially divided; and the erector spinae muscle remains intact.

While the first assistant gently elevates the corner of the scapula with a scapula retractor, the surgeon palpates and counts the ribs, starting from the second rib (the first rib is hardly palpable, except in small children) to identify the ICS (usually the 4th, sometimes the 3rd), where the hemithorax will be entered. The opening of the intercostal muscles and the underlying parietal pleura is always wider than the skin incision of the thoracotomy. Before entering the pleural space, the power of diathermy is reduced to a minimum and the anaesthetist is asked to deflate the lung. After entering the pleural space at a point with diathermy, the power of diathermy comes back to the usual, the ventilation restarts, though with less volume, and the pleura is completely opened with the diathermy. A pledget (commonly known as a ‘peanut’) on forceps under the parietal pleura, moving in parallel with the tip of diathermy, protects the underlying lung from thermal injury. A retractor is placed and gradually opened to avoid rib fractures.

Closure of thoracotomy

Types of cannulation

Aortic cannulation

The surgeon first inspects the aortic cannula for its type and size; the latter will determine the area of the purse-string suture site. The site of ascending aortic cannulation should always facilitate the optimal exposure for the procedure. Therefore, there is no ‘routine’ site for cannulation, but it should be as distal as possible, usually just below the origin of the innominate artery (Jonas 2014). The surgeon inspects the aortic cannula for its size which will determine the area of the purse-string suture site. Two purse-string sutures (prolene or Ethibond 4-0 or 5-0) are placed through the adventitia and the media of the aortic wall in a circular shape. In small aortas, as in children, it is preferable for the purse-string sutures to be placed in a ‘rhombus shape’ with the long axis of the ‘rhombus’ parallel to the long axis of the ascending aorta (AscAo) to avoid supravalvular aortic stenosis, after the purse string sutures are tied down. In small children, one purse-string suture can be used.

The adventitia within the purse-string sutures is incised carefully with fine scissors (or diathermy) to the media. The surgeon grips firmly with forceps the upper aortic purse-string with the adventitia and retracts it up. Then, with a No11 blade, the surgeon makes a small horizontal stab at the centre of the dissected cannulation site, which is opened with the blade slightly but adequately to accommodate the aortic cannula. As the blade is removed, the aortotomy is closed with a downward move of the adventitia with the forceps. The surgeon then opens the aortotomy with the forceps and inserts the cannula to the aortic lumen (Mavroudis 2015).

In the case of a ‘rhombus shape’ purse-string suture line, the surgeon grips firmly with vascular forceps the purse-string suture line with the adventitia on their side, while the first assistant does the same opposite the surgeon’s grip. If the AscAo is not long enough, the second assistant can help retract it gently downwards with their left hand, using a Roberts forceps and grasping the adventitia above the sinuses of Valsalva. In their right hand, the second assistant holds a pump sucker. The surgeon with a No 11 blade makes an aortotomy in a vertical direction, along the long axis of the ‘rhombus-shaped’ purse-string. As the blade is removed, the surgeon and the first assistant close the aortotomy with a synchronised move, with their forceps holding the adventitia.

Superior vena cava cannulation

The surgeon inspects the superior vena cava (SVC) cannula for its size which will determine the area of the purse-string suture site. The AscAo is gently retracted medially by the second assistant, with a Farabeuf or a venous retractor. The appendage of an enlarged RA may have to be retracted downwards with a free heavy silk ligature tied to its tip bearing a mosquito at its end. A double-ended purse-string suture (prolene No 4-0) is placed to the SVC, starting some millimetres above the SVC-to-RA junction, where the sinoatrial node is located, with the two legs of the double-ended suture coming upwards in parallel course alongside the SVC, and meeting at about the entrance of the left innominate vein to SVC. The SVC is minimally dissected, from the right pulmonary artery underneath, using diathermy for the medial aspect of SVC and fine scissors for the lateral aspect, where the phrenic nerve courses which may be injured due to diathermy conduction. With the aid of a dissector, an umbilical tape with a snare is passed around the SVC, without being snugged at this point ensuring the azygous vein is above the placement of the snare.

The surgeon then uses fine forceps to lift the purse-string with the adventitia on their side, while the first assistant does the same opposite the surgeon, and, with a second, stronger forceps, retracts the lower ‘corner’ of the purse-string suture downward. The second assistant still retracts the AscAo and holds a pump sucker to clear the field from bleeding during cannulation.

The surgeon with the No 11 blade makes a small venotomy to the SVC between the two forceps. As the blade is removed, the surgeon and the first assistant in a synchronised move use their forceps to close the venotomy. The surgeon and the first assistant then in a synchronised move open the venotomy with their forceps, and the surgeon with a Roberts forceps opens the venotomy enough to accommodate the SVC cannula. As the Roberts forceps is removed, the widened venotomy is closed again with the forceps. The venotomy is then opened again and the surgeon inserts a right-angled cannula (Edwards™) to the SVC lumen. The first assistant snugs down the cannula and the surgeon secures it in place with a heavy tie around the cannula and the snugger. The cannula is de-aired, clamped, and connected to one leg of a Y-connector, which is connected to the venous line. After CPB is initiated, the umbilical tape around the SVC cannula is snugged down.

Inferior vena cava cannulation

The surgeon then uses forceps to lift the upper line of the purse-string with RA wall and, with a No11 blade, stabs the atrial wall at the centre of the purse-string suture. As the blade is removed, the surgeon closes the hole of the stabbing with the forceps. The surgeon then opens the atrial hole and, with a Roberts forceps, widens the atrial hole to accommodate the IVC cannula. As the Roberts forceps is removed, the widened atrial hole is closed again with the forceps. Finally, the surgeon again opens the atrial hole and inserts a right-angled cannula (Edwards™) to the IVC lumen. The first assistant snugs down the cannula and the surgeon secures it in place with a heavy tie around the cannula and the snugger. The cannula is de-aired, clamped and connected to the free leg of the Y-connector of the venous line. After CPB is initiated, the umbilical tape around the SVC cannula is snugged down.

Cardioplegia site

The cardioplegia site is usually above the sinuses of Valsalva. The adventitia of the aorta is opened for 2–3mm with diathermy. A purse-string suture (prolene No 4-0) with a snare is placed around the dissected opening of the adventitia. The cardioplegia catheter is then inserted to the aorta and fixed in place with the snared purse-string suture. The needle guide is removed, the flow is checked, and the catheter is clamped with a mosquito clamp. In coordination with the perfusionist, the cardioplegia line is de-aired and connected to the cardioplegia catheter.

In addition to cardioplegia, we use topical cooling of the heart with ice slush (temperature 4°C) for further cardiac protection during CPB.

Right atriotomy

After the cardioplegia solution is in, the IVC cannula is snugged. The right atrium is opened initially with a No 11 blade at a point at the RA appendage. A pump sucker is placed within the RA to permit the surgeon to complete the atriotomy. With Metzenbaum scissors, an oblique, parallel to the atrioventricular groove, right atriotomy is performed, starting from the initial stabbing at the base of the RA appendage and ending medially to the IVC cannula. If there is an interatrial communication (patent foramen ovale [PFO] and atrial septal defect), a vent is placed through it to the left heart. If not, an iatrogenic PFO is created with a No11 blade at the centre of the fossa ovalis for the insertion of the vent. Three stay sutures (silk No 4-0) are placed within the RA to keep the atriotomy open: one at hour 9, towards the surgeon’s position, fixing the atrial wall to the adjacent pericardium; the other two are placed backhands at hours 2 and 5, towards the first assistant’s position, retracting medially the RA wall with the weight of mosquito clamps at their ends.

Pacing wires

We use two monofilament temporary cardiac pacing leads (FlexonTM, Covidien^®) for the RA and two for the Right Ventricle (RV). The wires have one end where the lead is bare and has a curved needle (for fixing to the epicardium), while the other end has a long straight needle (for coming out of the chest). The ventricular pacing wires are fixed to the RV epicardium in the following way: the curved needle of the wire is passed superficially through the epicardium, avoiding coronary vessels, and comes out, leaving part of the bare end of the lead inside the epicardium. A prolene suture No 5-0 is passed around the lead at its entrance to the epicardium, and is initially tightened around the lead with three knots; then the free end of the lead with the curved needle comes between the legs of the suture and three more knots are placed to complete the process of fixing the lead to the epicardium.

The curved needle and the suture ends are cut in one move with heavy scissors, and the free end of the lead is made curled with the aid of two forceps. If any bleeding occurs from the entry and exit points of the wire needle to the epicardium or the fixing suture, it can be controlled with additional shallow bites (prolene No 5-0) or wait for the protamine to act at the end of the procedure. The atrial pacing wires are fixed to the RA epicardium in the following way: a fixing suture (prolene No 5-0) is passed superficially through the epicardium of the RA appendage twice to create a loop; the curved needle of the lead is cut and the bare end of the lead is angled to 45° with a forceps by the scrub practitioner. The bare end is then passed through the loop of the fixing prolene suture by the first assistant, who tries to keep it within the loop as the surgeon tightens down the knots fixing the lead to the RA.

Another way of fixing the atrial pacing wires to the atrial wall is to use the second suture row of the atriotomy closure, which is over-and-over suture, and fix the bare end of the lead angled to 45° under two separate loops of the suture line at the time of suturing. No additional fixing sutures are required. Both the two ventricular wires and the two atrial pacing wires come out of the chest together: the atrial on the right side, and the ventricular on the left side, as a rule, with the aid of the long straight needle at the other end of the wire. Both wires are made into a loose knot close to their exit from the skin and are fixed to the skin with No. 2-0 silk sutures around the wire knot. For removal, the fixing silk sutures have to be cut (using blade No 11 or 15) and then the wires are pulled out. If there is resistance when pulling them out, it is safer for them to be cut with heavy scissors and left inside the chest.

Chest drains

Chest drains are placed routinely after heart procedures. As a rule, all opened intrathoracic cavities (mediastinum and pleural cavities) should be drained with tubes of adequate size. The drains must be placed so as not to touch the heart; we therefore avoid retro-cardiac drains, which may irritate an already irritable heart, causing arrhythmias.

When a reoperation is anticipated, for the great vessels and the heart to be protected during redo surgery, they should be covered either with the native pericardium alone, if feasible, or with a synthetic (PTFE, Gore-Tex^®) pericardial membrane, which is anchored with a few interrupted sutures (prolene No 5-0) to the rim of the remaining native pericardium.

Palliative surgical procedures

A palliative procedure provides symptomatic relief but leaves the main pathophysiology uncorrected. In congenital heart surgery, the two classic and most commonly used palliative procedures are:

• The systemic-pulmonary arterial shunt

• The pulmonary artery banding.

The aim of palliative procedures is to alter the haemodynamic physiology in order to improve the patient’s condition and permit growth until complete correction can be carried out.

Systemic-pulmonary arterial shunts

Classic Blalock-Taussig shunt

The classic Blalock-Taussig Shunt is a direct end-to-side anastomosis of the transected subclavian artery to the ipsilateral PA.

Advantages:

• It provides a precise amount of pulmonary blood flow, limited by the orifice of the SCA

• It enlarges with somatic growth, which provides more pulmonary blood flow

• No prosthetic material is used (Mery & Turek 2011; Jonas 2014).

Disadvantages:

• The SCA is sacrificed, which in some patients has led to devastating extremity ischaemia

• The affected arm is often shorter than the contralateral one and will not have a palpable pulse

• Because of the limited length of the SCA and the distance required for translocation, the PA is easily distorted, complicating further palliative procedures that rely on passive pulmonary blood flow (Mery & Turek 2011; Jonas 2014).

Nowadays this shunt has been replaced by the modified Blalock-Taussig shunt.

Modified Blalock-Taussig shunt

Modified Blalock-Taussig shunt procedure

For a median sternotomy, the right lobe of thymus is excised, and the left innominate vein is dissected free and suspended with a silastic vessel loop. The pericardium is opened just over the great vessels in an inverted T-fashion and suspended with four No 2-0 silk sutures. The anatomy of the great vessels and the heart is inspected. The innominate artery is usually selected as the driving artery for the BT shunt; it is therefore dissected up to its bifurcation and encircled with a silastic vessel loop. If the right subclavian artery is selected, then the dissection of the innominate artery continues to the right subclavian artery, which is mobilised free and encircled with a silastic vessel loop. Then, for the dissection of the RPA and the construction of the distal anastomosis of the BT shunt to be facilitated, it is necessary for the (usually large) AscAo to be suspended towards the left. A double-ended pledgeted, prolene suture No 5-0 is placed through the adventitia of the right lateral aspect of the AscAo in order to pull upwards and medially the AscAo, without disturbing haemodynamics, and it is secured with a clip to the drapes on the left side of the sternotomy.

The RPA is then dissected proximally up to the MPA bifurcation, or the PDA origin, and distally down to the RPA bifurcation. The two (or three) branches of the RPA are double-encircled with snared silk ties No 0 or with silastic vessel loops. The activated clotting time (ACT) is checked and will be the baseline for the following measurements. Heparin is administered IV (30 IU/kg, depending on the baseline ACT) for a target ACT of 180–200 seconds during the procedure. The innominate artery is clamped with a side vascular clamp.

The surgeon and the first assistant use micro-ring tips forceps to grip the adventitia opposite each other and gently elevate it. An arteriotomy is made, using a beaver blade to the adventitia and to the muscular layer, and a micro sharp blade to the intima to enter the lumen. The arteriotomy is widened with Potts scissors to match the diameter of the selected conduit. The lumen of the artery is flushed with heparinised saline with a fine tip syringe. A stay suture (prolene No 6-0) can be placed to the adventitia of the anterior wall of the arteriotomy, at its midpoint, close to its rim, and be retracted gently with a mosquito, to keep the arteriotomy open during the anastomosis without the need to use forceps.

The conduit (PTFE, Gore-Tex^®) is cut obliquely (no more than a 45° angle) at its one end and anastomosed end-to-side to the innominate arteriotomy with a continuous suture (prolene No 7-0). After completion of the proximal anastomosis of the shunt, the conduit is occluded with a bulldog or a ‘lady J’ vessel clamp, and the occluding side clamp is released from the innominate artery, for the integrity of the proximal anastomosis to be checked.

A small arteriotomy is made to the upper wall of the RPA. Unlike the arteriotomy to the innominate artery, the pulmonary arteriotomy should be slightly smaller than the size of the conduit, as it enlarges during the anastomosis by the tension of the sutures to the weaker pulmonary arterial wall. A stay suture (prolene No 6-0) can be placed to the adventitia of the anterior wall of the arteriotomy, as for the proximal anastomosis, to keep the arteriotomy open during the anastomosis without the need to use forceps near a fragile vessel wall. The free end of the conduit is then anastomosed to RPA with continuous suture (prolene No 6-0 or 7-0).

• Single ventricle physiology with increased pulmonary blood flow in preparation for future Fontan procedure

• To prepare and retrain the LV in patients with TGA for future arterial switch procedure (Jonas 2014; Mery & Turek 2011).

In patients with normally related great vessels, PAB may be performed either through a median sternotomy (preferred) or a left thoracotomy. Banding material will be chosen according to the surgeon’s preference, with the most common being the umbilical tape, the expanded Polytetrafluoroethylene (Gore-Tex^®) tubular graft, and the silastic vessel loop. Anatomically, PA bands are placed circumferentially around the mid-MPA.

Safety and effectiveness guidelines for PAB

• The main pulmonary artery pressure (PAP) should be reduced to 35-50% of systemic BP in patients for future biventricular repair

• For patients in whom a single ventricle palliation (Fontan) is anticipated, the lowest possible distal main PAP is the target

• Saturation of O2 for anticipated biventricular repair should be at 85-90%; if the final pathway is a Fontan procedure, SatsO2 80-85% will be acceptable

• The initial circumference of the band is grossly guided by Trusler’s rule:

• 20mm + 1mm for each kg of BW in acyanotic CHDs (VSDs, atrioventricular septal defects),

• 24mm + 1mm for each kg of BW in cyanotic/mixing defects (single ventricle, TGA) (Mery & Turek 2011; Jonas 2014).

As the patient grows, PAB tightness increases, further decreasing distal PA pressure and O2 saturation.

PAB procedure

Median sternotomy is performed. The left, or right, lobe of the thymus is excised. The pericardium is opened over the great vessels in an inverted fashion and suspended with stay sutures (silk No 2-0). The anatomy and position of the great vessels are inspected. The MPA and its branches are recognised, and at their bifurcation the origin of the PDA. Using either mosquito and/or dissecting forceps, the PDA is dissected at its origin and ligated with a heavy tie (silk No 2).