432
Journal of the Royal Society ofMedicine Volume 72 June 1979
Changing pattern of congenital heart disease: a review' J L Wilkinson MB MRCP Royal Liverpool Children's Hospital Myrtle Street, Liverpool L7 7DG
Whilst congenital anomalies of the heart have been recognized and documented for many centuries, clinical diagnosis of most congenital cardiac defects and effective treatment for them has only become possible within the last 40 years.
Early history Looking at the earliest descriptions of congenital heart defects it is notable that a number of distinguished physicians and anatomists were prominent. Galen, nearly 2000 years ago, is quoted as having described patency of the ductus; Fabricius (whose 'bursa' is well known to students of immunology) described dextrocardia in 1600; and Stenson (of 'parotid duct' renown) gave the first account of what we currently call Fallot's tetralogy in 1671. In 1760 Morgagni, whose diaphragmatic hernia is familiar to many, found coarctation of the aorta in a monk. The first well documented specimen of transposition of the great arteries was that of Matthew Baillie (1797) and it is interesting to note how clearly he understood the pathophysiology of what he termed 'so singular a monstrosity'. He wrote: 'A florid blood must have been always circulating between the lungs and the left side of the heart, except for the admixture of the dark blood which passed through the small communication of the foramen ovale, and a dark blood must have been always circulating between the right side of the heart and the general mass of the body, except for the.very small quantity of florid blood which passed into the aorta by the remains of the ductus arteriosus' (Baillie 1797). Seventeen years later John Farre published in London a monograph entirely devoted to congenital heart disease, and his descriptions of many anomalies are a model of clarity. He included clinical details of many of his cases and described amongst the features of cyanotic patients, with what was undoubtedly Fallot's tetralogy, swelling of the tips of the fingers (finger clubbing), cyanotic attacks and cerebral abscess (Farre 1814). During the nineteenth century a very large number of publications on the pathology and embryology of cardiac defects appeared and these continued into the twentieth century, culminating with the massive pathological study of Maude Abbott (1927). The first major attempts to produce a comprehensive account of the clinical features of congenital heart disease and to give guidance on its accurate diagnosis were those of the Grimsby physician, James Brown (1939), and the magnificent work of Helen Taussig (1947) which has been the model for most subsequent reference texts on the subject.
Surgery for congenital heart disease To Helen Taussig, at Johns Hopkins, credit must be given for providing much of the drive and stimulus as a result of which paediatric cardiology and paediatric cardiac surgery have subsequently flourished. Her encouragement led Alfred Blalock in the early 1940s to perform the first subclavian to pulmonary shunt (Figure 1) for cyanotic heart disease (Blalock & Taussig 1945). The dramatic transformation of severely cyanosed and hopelessly handicapped patients into happy and near pink children, with vastly increased exercise tolerance, opened the eyes of the interested world to the possibilities of surgery for congenital heart disease. 1 Paper read to Section of Anaesthetics, 2 December 1977. Accepted 7 March 1978 0 141-0768/79/060432-08/$O 1.00/0
,?"
1979 The Royal Society of Medicine
Journal of the Royal Society ofMedicine Volume 72 June 1979
433
Successful ligation of a patent ductus had antedated this achievement, being first performed by Gross (1939) with striking, if somewhat less dramatic, benefit to patients. During the 1940s coarctation was repaired (Crafoord & Nylin 1945), and surgeons all over the world became increasingly enthusiastic about the possibility of surgery for children with heart defects. Much research into heart-lung bypass was carried out during the 1940s, following the pioneering work of Gibbon (1939), culminating in the perfection of a rotating disc oxygenator by Melrose at the Hammersmith Hospital in 1952, and a bubble oxygenator by Lillehei in Minneapolis at about the same time (Wangenstein 1975, Melrose 1969). Prior to the clinical use of heart-lung bypass a variety of attempts were made to approach the inside of the heart 'blind', and the use of moderate hypothermia was also explored. Using hypothermia, closure of an atrial septal defect was performed under direct vision by Lewis in September 1952. In May 1953 Gibbon achieved the first clinical success with extracorporeal circulation (Wangenstein 1975).
(4K~~~G
Figure 1. Schematic diagram showing subclavian to pulmonary anastomosis (Blalock & Taussig 1945) for Fallot's tetralogy
The first closure of ventricular septal defect, repair of Fallot's tetralogy and operation on an atrioventricular canal defect were all carried out by Lillehei and his team in Minneapolis during 1954, using cross circulation between parent and patient (Lillehei 1975). In 1954-55, clinical use of a bubble oxygenator by Lillehei, and of the Melrose machine at the Hammersmith Hospital, supplanted other methods of gaining access to the inside of the heart in most major cardiac defects. However, hypothermia continues to be used, mainly in conjunction with bypass, for some surgical procedures - particularly in small infants.
Cardiac catheterization During the early years of cardiac surgery the surgeon had to rely on clinical diagnosis of the cardiac defect to make decisions about surgery. Whilst in many simple defects such diagnoses were fairly reliable, in the more complex situations and in cyanotic defects they were less so. The development of cardiac catheterization and angiocardiography, which proceeded during the 1940s and early 1950s, revolutionized diagnostic cardiology. Cardiac catheterization had first been carried out by Werner Forssman, on himself, in Germany in 1929. Dr Forssman had seen fatalities result from intracardiac injection of adrenalin producing tamponade, and he conceived the idea of giving injections via a catheter introduced to the right atrium from a peripheral vein. To test the idea he persuaded a colleague to cutdown on his own arm vein and pass a catheter up it. The colleague became alarmed when the catheter reached the axilla and refused to advance it any further. Dr Forssman therefore
434
Journal of the Royal Society ofMedicine Volume 72 June 1979
completed the procedure himself, proving the catheter's location in the atrium by taking an X-ray. He felt no discomfort and subsequently repeated the procedure on eight occasions, before finally running out of suitable superficial veins. Being unable to convince the German medical establishment of the value of the procedure he subsequently left hospital medicine and went into general practice. Many years later he shared a Nobel prize for his pioneering contribution (McMichael 1969). Catheterization was developed during the 1 940s by Cournand and colleagues in New York, and in Britain much early work was done by McMichael. The earliest attempts at angiography were made by Forssman in his original experiments on himself, but the development of suitable techniques for obtaining good quality serial pictures following contrast injection took many years, and even in the early 1950s apparatus for changing films was reminiscent of Heath Robinson contraptions (Figure 2). At the present time selective angiocardiography is the cornerstone of accurate anatomical diagnosis in congenital heart disease (Figure 3). It is noteworthy that the ability to demonstrate, in minute detail, the complexities of many congenital cardiac deformities has led
Figure 2. Diagram to show hand-operated film changer in use in the early 1 950s (drawn by Professor John D Hay). The operator (right) needed considerable strength and fitness to move the films through, with a wooden slide, beneath the patient; with practice a rate of 2 frames per second could be achieved. The assistant (left) needed the talents of a rugby scrum half to retrieve the exposed plates as they emerged
Figure 3. Left ventricular angiocardiogram from patient with transposition of the great vessels. The pulmonary arteries are filled from the left ventricle. (Courtesy Dr R W Galloway) a
Journal of the Royal Society of Medicine Volume 72 June 1979
435
to a recent resurgence of interest by cardiologists in the pathological anatomy of congenital heart defects, an area of knowledge which has been somewhat overshadowed by the rapid expansion in understanding of the physiology and pathophysiology of congenital cardiopathies which occurred in the earlier years of cardiac catheterization. For the cardiac surgeon the precise demonstration of anatomic defects by angiography has brought enormous dividends, for accurate preoperative diagnosis makes his task very much simpler. The nature of the anomaly is often easier to define angiographically than on the operating table. Indeed, the once familiar spectacle of an irate surgeon taking his cardiologist to task for failing to reach the correct diagnosis preoperatively is now largely a thing of the past.
Echocardiography A diagnostic technique which has recently made a considerable impact on preoperative and postoperative assessment is echocardiography. This noninvasive investigation has already
T1
K
LV
1 \
'.-LV
Piezo-electric crystal
T
R
Figure 4. Illustrates differences in principle between use of X-ray (left) and reflected ultrasound (right) to examine the heart. Ultrasound reflected from tissue interfaces is picked up when it returns to the transducer (T) - the 'echo'. (Courtesy Dr Robert Arnold)
found a substantial place in the field of congenital heart disease, and newer modifications show further promise. The principle of the procedure is to direct a pulsed ultrasound beam through the heart from a crystal in contact with the anterior chest wall (Figure 4). A proportion of the ultrasound is reflected from each tissue interface or tissue/blood interface, and is detected by the transducer and converted into a visual signal on an oscilloscope. By showing this signal on a time scan it is possible to demonstrate the various reflecting structures moving as the heart contracts (Figure 5). The pictures produced in this way, called the M (motion) mode, are the now familiar echocardiographic tracings (Figure 5). By directing the beam at different parts of the heart a number of different 'views' may be obtained. Using single-beam echocardiography the structure and function of the mitral and aortic valves and left ventricle can be examined in some detail. Examination of the tricuspid valve is also fairly simple, and the right ventricle is readily accessible. The pulmonary valve is less easy to demonstrate accurately. In congenital heart disease the technique is now in more or less routine use in many centres. It is of considerable value in the emergency assessment of the sick neonate, and may be diagnostic in severe forms of hypoplastic left heart syndrome. It is also particularly valuable in the assessment of cardiomyopathies and of patients with systolic murmurs of uncertain significance. In addition, it is extremely useful in the diagnosis of pericardial effusion.
436
Journal of the Royal Society of Medicine Volume 72 June 1979
The technique has a number of clear advantages: (1) Safety - there are no untoward side effects. (2) It is painless. (3) Quantitative: accurate measurements of valve and chamber size are possible. (4) Dynamic: it gives a clear picture of intracardiac structures moving with each heart beat. (5) Portable: the apparatus can be taken to a sick patient's bedside or to an infant in its incubator. (6) It is complementary to angiography, and can give some anatomic information not readily obtainable by angiography. (7) It is useful for research purposes. There are, however, several disadvantages as well - notably: (1) It is technically taxing, requires considerable training and skill to obtain useful records consistently, and may be very time consuming. (2) A number of artefactual echos may be produced in various ways and these may lead to misinterpretation unless recognized. (3) The lung provides a near-absolute barrier to transmission of ultrasound and may sometimes make a complete examination impossible. (4) Imaging is unidimensional. Development of two-dimensional echocardiography using 'multiple crystals' or 'sector scanning' shows promise of being a major advance. Further refinement of the uses of
r,,,_
Piezo - electric
-
crystal RV
/
'beam' (left) passes through right ventricle (RV), septum (IVS) and left ventricle (LV). The anterior mitral valve leaflet (AML) and posterior leaflet (PML) are clearly shown. Ao, aorta. LA, left atrium. (Courtesy Dr Robert Arnold)
ultrasound will undoubtedly bring major changes in the investigation of congenital heart disease and may, in time, replace angiography in some situations.
Surgery on infants As investigation and management of congenital heart disease has advanced in the past twenty years, the range of defects amenable to correction or palliation has greatly increased. Improvement in bypass technology, and adaptation of it to suit the smallest infant, has led to an increasing emphasis on early correction of many defects. Many surgeons prefer to use profound hypothermia and circulatory arrest to obtain ideal operating conditions in small infants (Hamilton et al. 1973), though it is technically possible to use conventional cardiopulmonary bypass at normothermia, even in very small babies. Using such techniques it is now common practice for many severe defects to be corrected in the early months of life - most notably ventricular septal defect, Fallot's tetralogy, transposition, and total anomalous pulmonary venous drainage; more complex problems, like common atrioventricular canal and truncus, are also now amenable to early correction.
Journal of the Royal Society of Medicine Volume 72 June 1979
437
Newer surgical procedures Coarctation Coarctation of the aorta is among the most lethal of the common congenital heart defects. A high proportion of infants presenting in the early weeks of life have a long-segment narrowing of the infantile type, although about half of those with the localized type of coarctation (adult type) also present early. Resection of the coarcted segment and end-to-end anastomosis is technically difficult in small infants with long-segment coarctation, and even resection of localized coarctation, when carried out in the first few months of life, is followed by a depressingly high incidence of restenosis (Shinebourne et al. 1976).
L. S. A.
-NJ
T.A.
P.D.A.
r~~~~~~~~~
r
Figure 6. Subclavian onlay flap aortoplasty, showing technique of repair by flap in severe long-segment coarctation. (Reproduced from Hamilton et al. 1978, by kind permission) Systolic ELP (mm Hg)
140
,........................................
120
.
***...p~~~~~~~~~~~~...........
2
so-
,,,8,,,
,,,,,,, ,.......
..........
60- : Age at follow-up
I 0
1
2
3
4
5
6
7
Figure 7. Systolic blood pressure in arm at follow up, in 18 infants with coarctation treated by subclavian flap aortoplasty before the age of 6 months. (Reproduced from Hamilton et al. 1978, by kind permission)
Since 1970 subclavian flap aortoplasty (Figure 6) has been used in Liverpool as the procedure of choice in all infants requiring surgery for coarctation. The procedure is technically straightforward, does not increase surgical risk, and has an extremely low incidence of restenosis. Moreover, arm blood pressure up to 7 years postoperatively shows no significant residual hypertension - in marked contrast to the findings after end-to-end anastomosis (Shinebourne et al. 1976) (Figure 7).
438
Journal of the Royal Society of Medicine Volume 72 June 1979
Conduit surgery
The use of homograft and heterograft valves, and valve-bearing conduits, has revolutionized the surgery of complex congenital heart defects in the past decade. Defects such as truncus, pulmonary atresia and tricuspid atresia are now amenable to radical reconstructive surgery, as are a variety of other complex defects. Figures 8 & 9 show the use of right ventricular to pulmonary artery conduits to repair truncus and pulmonary atresia respectively. For tricuspid atresia, radical surgery involves insertion of a conduit from the hypertrophied right atrium to the pulmonary artery, and closure of the atrial septal defect, with or without insertion of a valve or valves in the caval orifices. This procedure, known as 'ventricularization of the right atrium' was pioneered by the French surgeon Fontan, and is often called the Fontan procedure (Figure 1O).
Figure 8. Conduit repair for persistent truncus. A valve-bearing conduit is inserted between right ventricle and pulmonary arteries, which are disconnected from the 'truncus'. Closure of the ventricular septal defect to direct left ventricular blood to the 'aorta' completes the repair
Figure 9. Repair of pulmonary atresia. A valved conduit is inserted as in Figure 8
Figure 10. Operation for tricuspid atresia. A valved conduit is placed between right atrium and main pulmonary artery. The atrial septal defect is closed to force systemic venous blood through the conduit into the pulmonary circulation. The right atrium is thus 'ventricularized'
Univentricular heart The surgery of univentricular heart is another area of development. Insertion of a prosthetic septum into the single ventricle has been performed successfully in a number of patients (Danielson 1978, Hamilton 1978) and can produce gratifying results. Figure 11 shows a postoperative left ventricular angiogram from a boy who had such an operation, and who is now captain of his school football team. An alternative procedure for the univentricular heart is to use a modification of the Fontan procedure which involves closing the right atrioventricular valve in addition to the insertion of a conduit from atrium to pulmonary artery.
Journal of the Royal Society of Medicine Volume 72 June 1979
439
Figure 11. Left ventricular angiogram (diastolic frame) from a patient who had a prosthetic septum inserted six years previously for 'single ventricle'. (Courtesy Dr R W Galloway)
Conclusions From this brief review of the background and development of investigation and surgery for congenital heart disease, and of some currently topical aspects of the work, it will be seen that the dramatic and rapid developments of the past forty years have brought great changes in the diagnosis, surgery, and prognosis of congenital heart diseases. The range of defects amenable to effective and long-lasting treatment continues to increase. Surgery can be offered to many children at an early stage, before the effects of heart disease have led to the gross physical and psychological handicap for child (and family) which were so familiar in earlier times. References Abbot M E (1927) In: Modern Medicine. Ed. W Osler & T McCrea. Lea & Febiger, Philadelphia; vol 4 Baillie M (1797) The Morbid Anatomy of some of the most important parts of the human body. 2nd edn. Johnson & Nicol, London Blalock A & Taussig H B (1945) Journal of the American Medical Association 128, 189 Brown J W (1939) Congenital Heart Disease. John Bale Medical, London Crafoord C & Nylin G (1945) Journal of Thoracic Surgery 14, 347 Danielson G K (1978) In: Paediatric Cardiology 1977. Ed. R H Anderson and E A Shinebourne. Churchill Livingstone, Edinburgh; p 381 Farre J R (1814) Pathological Researches. Longman, London Gibbon J (1939) quoted by Wangenstein (1975) Gross R E (1939) Annals of Surgery 110, 321 Hamilton D I (1978) In: Paediatric Cardiology 1977. Eds. R H Anderson and E A Shinebourne. Churchill Livingstone, Edinburgh; p 388 Hamilton D I, Di Eusanio G, Sandrasagra F A & Donnelly R J (1978) Journal of Thoracic and Cardiovascular Surgery 75, 699 Hamilton D I, Shackleton J, Rees G J & Abbot T (1973) In: Heart Disease in Infancy, Diagnosis and Surgical Treatment. Ed. B G Barratt-Boyes, J M Neutze and E A Harris. Churchill Livingstone, Edinburgh; p 52 Lillehei C W (1975) In: Congenital Malformations of the Heart. Ed. D A Goor and C W Lillehei. Grune & Stratton, New York; p xv Melrose D G (1969) In: Medical and Surgical Cardiology. Ed. W Cleland, J Goodwin, et al. Blackwell, Oxford; p 315 McMichael J (1969) In: Cardiac Catheterization and Angiography. Ed. D Verel and R G Grainger. Livingstone, Edinburgh; p v Shinebourne E A, Tam A S Y, Elseed A M, Paneth M, Lennox S C, Cleland W P, Lincoln C, Joseph M C & Anderson R H (1976) British Heart Journal 38, 275 Taussig H B (1947) Congenital Malformations of the Heart. Commonwealth Fund, New York Wangenstein 0 H (1975) In: Congenital Malformations of the Heart. Ed. D A Goor and C W Lillehei. Grune & Stratton, New York; p xi
Journal of the Royal Society ofMedicine Volume 72 June 1979
Changing pattern of congenital heart disease: a review' J L Wilkinson MB MRCP Royal Liverpool Children's Hospital Myrtle Street, Liverpool L7 7DG
Whilst congenital anomalies of the heart have been recognized and documented for many centuries, clinical diagnosis of most congenital cardiac defects and effective treatment for them has only become possible within the last 40 years.
Early history Looking at the earliest descriptions of congenital heart defects it is notable that a number of distinguished physicians and anatomists were prominent. Galen, nearly 2000 years ago, is quoted as having described patency of the ductus; Fabricius (whose 'bursa' is well known to students of immunology) described dextrocardia in 1600; and Stenson (of 'parotid duct' renown) gave the first account of what we currently call Fallot's tetralogy in 1671. In 1760 Morgagni, whose diaphragmatic hernia is familiar to many, found coarctation of the aorta in a monk. The first well documented specimen of transposition of the great arteries was that of Matthew Baillie (1797) and it is interesting to note how clearly he understood the pathophysiology of what he termed 'so singular a monstrosity'. He wrote: 'A florid blood must have been always circulating between the lungs and the left side of the heart, except for the admixture of the dark blood which passed through the small communication of the foramen ovale, and a dark blood must have been always circulating between the right side of the heart and the general mass of the body, except for the.very small quantity of florid blood which passed into the aorta by the remains of the ductus arteriosus' (Baillie 1797). Seventeen years later John Farre published in London a monograph entirely devoted to congenital heart disease, and his descriptions of many anomalies are a model of clarity. He included clinical details of many of his cases and described amongst the features of cyanotic patients, with what was undoubtedly Fallot's tetralogy, swelling of the tips of the fingers (finger clubbing), cyanotic attacks and cerebral abscess (Farre 1814). During the nineteenth century a very large number of publications on the pathology and embryology of cardiac defects appeared and these continued into the twentieth century, culminating with the massive pathological study of Maude Abbott (1927). The first major attempts to produce a comprehensive account of the clinical features of congenital heart disease and to give guidance on its accurate diagnosis were those of the Grimsby physician, James Brown (1939), and the magnificent work of Helen Taussig (1947) which has been the model for most subsequent reference texts on the subject.
Surgery for congenital heart disease To Helen Taussig, at Johns Hopkins, credit must be given for providing much of the drive and stimulus as a result of which paediatric cardiology and paediatric cardiac surgery have subsequently flourished. Her encouragement led Alfred Blalock in the early 1940s to perform the first subclavian to pulmonary shunt (Figure 1) for cyanotic heart disease (Blalock & Taussig 1945). The dramatic transformation of severely cyanosed and hopelessly handicapped patients into happy and near pink children, with vastly increased exercise tolerance, opened the eyes of the interested world to the possibilities of surgery for congenital heart disease. 1 Paper read to Section of Anaesthetics, 2 December 1977. Accepted 7 March 1978 0 141-0768/79/060432-08/$O 1.00/0
,?"
1979 The Royal Society of Medicine
Journal of the Royal Society ofMedicine Volume 72 June 1979
433
Successful ligation of a patent ductus had antedated this achievement, being first performed by Gross (1939) with striking, if somewhat less dramatic, benefit to patients. During the 1940s coarctation was repaired (Crafoord & Nylin 1945), and surgeons all over the world became increasingly enthusiastic about the possibility of surgery for children with heart defects. Much research into heart-lung bypass was carried out during the 1940s, following the pioneering work of Gibbon (1939), culminating in the perfection of a rotating disc oxygenator by Melrose at the Hammersmith Hospital in 1952, and a bubble oxygenator by Lillehei in Minneapolis at about the same time (Wangenstein 1975, Melrose 1969). Prior to the clinical use of heart-lung bypass a variety of attempts were made to approach the inside of the heart 'blind', and the use of moderate hypothermia was also explored. Using hypothermia, closure of an atrial septal defect was performed under direct vision by Lewis in September 1952. In May 1953 Gibbon achieved the first clinical success with extracorporeal circulation (Wangenstein 1975).
(4K~~~G
Figure 1. Schematic diagram showing subclavian to pulmonary anastomosis (Blalock & Taussig 1945) for Fallot's tetralogy
The first closure of ventricular septal defect, repair of Fallot's tetralogy and operation on an atrioventricular canal defect were all carried out by Lillehei and his team in Minneapolis during 1954, using cross circulation between parent and patient (Lillehei 1975). In 1954-55, clinical use of a bubble oxygenator by Lillehei, and of the Melrose machine at the Hammersmith Hospital, supplanted other methods of gaining access to the inside of the heart in most major cardiac defects. However, hypothermia continues to be used, mainly in conjunction with bypass, for some surgical procedures - particularly in small infants.
Cardiac catheterization During the early years of cardiac surgery the surgeon had to rely on clinical diagnosis of the cardiac defect to make decisions about surgery. Whilst in many simple defects such diagnoses were fairly reliable, in the more complex situations and in cyanotic defects they were less so. The development of cardiac catheterization and angiocardiography, which proceeded during the 1940s and early 1950s, revolutionized diagnostic cardiology. Cardiac catheterization had first been carried out by Werner Forssman, on himself, in Germany in 1929. Dr Forssman had seen fatalities result from intracardiac injection of adrenalin producing tamponade, and he conceived the idea of giving injections via a catheter introduced to the right atrium from a peripheral vein. To test the idea he persuaded a colleague to cutdown on his own arm vein and pass a catheter up it. The colleague became alarmed when the catheter reached the axilla and refused to advance it any further. Dr Forssman therefore
434
Journal of the Royal Society ofMedicine Volume 72 June 1979
completed the procedure himself, proving the catheter's location in the atrium by taking an X-ray. He felt no discomfort and subsequently repeated the procedure on eight occasions, before finally running out of suitable superficial veins. Being unable to convince the German medical establishment of the value of the procedure he subsequently left hospital medicine and went into general practice. Many years later he shared a Nobel prize for his pioneering contribution (McMichael 1969). Catheterization was developed during the 1 940s by Cournand and colleagues in New York, and in Britain much early work was done by McMichael. The earliest attempts at angiography were made by Forssman in his original experiments on himself, but the development of suitable techniques for obtaining good quality serial pictures following contrast injection took many years, and even in the early 1950s apparatus for changing films was reminiscent of Heath Robinson contraptions (Figure 2). At the present time selective angiocardiography is the cornerstone of accurate anatomical diagnosis in congenital heart disease (Figure 3). It is noteworthy that the ability to demonstrate, in minute detail, the complexities of many congenital cardiac deformities has led
Figure 2. Diagram to show hand-operated film changer in use in the early 1 950s (drawn by Professor John D Hay). The operator (right) needed considerable strength and fitness to move the films through, with a wooden slide, beneath the patient; with practice a rate of 2 frames per second could be achieved. The assistant (left) needed the talents of a rugby scrum half to retrieve the exposed plates as they emerged
Figure 3. Left ventricular angiocardiogram from patient with transposition of the great vessels. The pulmonary arteries are filled from the left ventricle. (Courtesy Dr R W Galloway) a
Journal of the Royal Society of Medicine Volume 72 June 1979
435
to a recent resurgence of interest by cardiologists in the pathological anatomy of congenital heart defects, an area of knowledge which has been somewhat overshadowed by the rapid expansion in understanding of the physiology and pathophysiology of congenital cardiopathies which occurred in the earlier years of cardiac catheterization. For the cardiac surgeon the precise demonstration of anatomic defects by angiography has brought enormous dividends, for accurate preoperative diagnosis makes his task very much simpler. The nature of the anomaly is often easier to define angiographically than on the operating table. Indeed, the once familiar spectacle of an irate surgeon taking his cardiologist to task for failing to reach the correct diagnosis preoperatively is now largely a thing of the past.
Echocardiography A diagnostic technique which has recently made a considerable impact on preoperative and postoperative assessment is echocardiography. This noninvasive investigation has already
T1
K
LV
1 \
'.-LV
Piezo-electric crystal
T
R
Figure 4. Illustrates differences in principle between use of X-ray (left) and reflected ultrasound (right) to examine the heart. Ultrasound reflected from tissue interfaces is picked up when it returns to the transducer (T) - the 'echo'. (Courtesy Dr Robert Arnold)
found a substantial place in the field of congenital heart disease, and newer modifications show further promise. The principle of the procedure is to direct a pulsed ultrasound beam through the heart from a crystal in contact with the anterior chest wall (Figure 4). A proportion of the ultrasound is reflected from each tissue interface or tissue/blood interface, and is detected by the transducer and converted into a visual signal on an oscilloscope. By showing this signal on a time scan it is possible to demonstrate the various reflecting structures moving as the heart contracts (Figure 5). The pictures produced in this way, called the M (motion) mode, are the now familiar echocardiographic tracings (Figure 5). By directing the beam at different parts of the heart a number of different 'views' may be obtained. Using single-beam echocardiography the structure and function of the mitral and aortic valves and left ventricle can be examined in some detail. Examination of the tricuspid valve is also fairly simple, and the right ventricle is readily accessible. The pulmonary valve is less easy to demonstrate accurately. In congenital heart disease the technique is now in more or less routine use in many centres. It is of considerable value in the emergency assessment of the sick neonate, and may be diagnostic in severe forms of hypoplastic left heart syndrome. It is also particularly valuable in the assessment of cardiomyopathies and of patients with systolic murmurs of uncertain significance. In addition, it is extremely useful in the diagnosis of pericardial effusion.
436
Journal of the Royal Society of Medicine Volume 72 June 1979
The technique has a number of clear advantages: (1) Safety - there are no untoward side effects. (2) It is painless. (3) Quantitative: accurate measurements of valve and chamber size are possible. (4) Dynamic: it gives a clear picture of intracardiac structures moving with each heart beat. (5) Portable: the apparatus can be taken to a sick patient's bedside or to an infant in its incubator. (6) It is complementary to angiography, and can give some anatomic information not readily obtainable by angiography. (7) It is useful for research purposes. There are, however, several disadvantages as well - notably: (1) It is technically taxing, requires considerable training and skill to obtain useful records consistently, and may be very time consuming. (2) A number of artefactual echos may be produced in various ways and these may lead to misinterpretation unless recognized. (3) The lung provides a near-absolute barrier to transmission of ultrasound and may sometimes make a complete examination impossible. (4) Imaging is unidimensional. Development of two-dimensional echocardiography using 'multiple crystals' or 'sector scanning' shows promise of being a major advance. Further refinement of the uses of
r,,,_
Piezo - electric
-
crystal RV
/
'beam' (left) passes through right ventricle (RV), septum (IVS) and left ventricle (LV). The anterior mitral valve leaflet (AML) and posterior leaflet (PML) are clearly shown. Ao, aorta. LA, left atrium. (Courtesy Dr Robert Arnold)
ultrasound will undoubtedly bring major changes in the investigation of congenital heart disease and may, in time, replace angiography in some situations.
Surgery on infants As investigation and management of congenital heart disease has advanced in the past twenty years, the range of defects amenable to correction or palliation has greatly increased. Improvement in bypass technology, and adaptation of it to suit the smallest infant, has led to an increasing emphasis on early correction of many defects. Many surgeons prefer to use profound hypothermia and circulatory arrest to obtain ideal operating conditions in small infants (Hamilton et al. 1973), though it is technically possible to use conventional cardiopulmonary bypass at normothermia, even in very small babies. Using such techniques it is now common practice for many severe defects to be corrected in the early months of life - most notably ventricular septal defect, Fallot's tetralogy, transposition, and total anomalous pulmonary venous drainage; more complex problems, like common atrioventricular canal and truncus, are also now amenable to early correction.
Journal of the Royal Society of Medicine Volume 72 June 1979
437
Newer surgical procedures Coarctation Coarctation of the aorta is among the most lethal of the common congenital heart defects. A high proportion of infants presenting in the early weeks of life have a long-segment narrowing of the infantile type, although about half of those with the localized type of coarctation (adult type) also present early. Resection of the coarcted segment and end-to-end anastomosis is technically difficult in small infants with long-segment coarctation, and even resection of localized coarctation, when carried out in the first few months of life, is followed by a depressingly high incidence of restenosis (Shinebourne et al. 1976).
L. S. A.
-NJ
T.A.
P.D.A.
r~~~~~~~~~
r
Figure 6. Subclavian onlay flap aortoplasty, showing technique of repair by flap in severe long-segment coarctation. (Reproduced from Hamilton et al. 1978, by kind permission) Systolic ELP (mm Hg)
140
,........................................
120
.
***...p~~~~~~~~~~~~...........
2
so-
,,,8,,,
,,,,,,, ,.......
..........
60- : Age at follow-up
I 0
1
2
3
4
5
6
7
Figure 7. Systolic blood pressure in arm at follow up, in 18 infants with coarctation treated by subclavian flap aortoplasty before the age of 6 months. (Reproduced from Hamilton et al. 1978, by kind permission)
Since 1970 subclavian flap aortoplasty (Figure 6) has been used in Liverpool as the procedure of choice in all infants requiring surgery for coarctation. The procedure is technically straightforward, does not increase surgical risk, and has an extremely low incidence of restenosis. Moreover, arm blood pressure up to 7 years postoperatively shows no significant residual hypertension - in marked contrast to the findings after end-to-end anastomosis (Shinebourne et al. 1976) (Figure 7).
438
Journal of the Royal Society of Medicine Volume 72 June 1979
Conduit surgery
The use of homograft and heterograft valves, and valve-bearing conduits, has revolutionized the surgery of complex congenital heart defects in the past decade. Defects such as truncus, pulmonary atresia and tricuspid atresia are now amenable to radical reconstructive surgery, as are a variety of other complex defects. Figures 8 & 9 show the use of right ventricular to pulmonary artery conduits to repair truncus and pulmonary atresia respectively. For tricuspid atresia, radical surgery involves insertion of a conduit from the hypertrophied right atrium to the pulmonary artery, and closure of the atrial septal defect, with or without insertion of a valve or valves in the caval orifices. This procedure, known as 'ventricularization of the right atrium' was pioneered by the French surgeon Fontan, and is often called the Fontan procedure (Figure 1O).
Figure 8. Conduit repair for persistent truncus. A valve-bearing conduit is inserted between right ventricle and pulmonary arteries, which are disconnected from the 'truncus'. Closure of the ventricular septal defect to direct left ventricular blood to the 'aorta' completes the repair
Figure 9. Repair of pulmonary atresia. A valved conduit is inserted as in Figure 8
Figure 10. Operation for tricuspid atresia. A valved conduit is placed between right atrium and main pulmonary artery. The atrial septal defect is closed to force systemic venous blood through the conduit into the pulmonary circulation. The right atrium is thus 'ventricularized'
Univentricular heart The surgery of univentricular heart is another area of development. Insertion of a prosthetic septum into the single ventricle has been performed successfully in a number of patients (Danielson 1978, Hamilton 1978) and can produce gratifying results. Figure 11 shows a postoperative left ventricular angiogram from a boy who had such an operation, and who is now captain of his school football team. An alternative procedure for the univentricular heart is to use a modification of the Fontan procedure which involves closing the right atrioventricular valve in addition to the insertion of a conduit from atrium to pulmonary artery.
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Figure 11. Left ventricular angiogram (diastolic frame) from a patient who had a prosthetic septum inserted six years previously for 'single ventricle'. (Courtesy Dr R W Galloway)
Conclusions From this brief review of the background and development of investigation and surgery for congenital heart disease, and of some currently topical aspects of the work, it will be seen that the dramatic and rapid developments of the past forty years have brought great changes in the diagnosis, surgery, and prognosis of congenital heart diseases. The range of defects amenable to effective and long-lasting treatment continues to increase. Surgery can be offered to many children at an early stage, before the effects of heart disease have led to the gross physical and psychological handicap for child (and family) which were so familiar in earlier times. References Abbot M E (1927) In: Modern Medicine. Ed. W Osler & T McCrea. Lea & Febiger, Philadelphia; vol 4 Baillie M (1797) The Morbid Anatomy of some of the most important parts of the human body. 2nd edn. Johnson & Nicol, London Blalock A & Taussig H B (1945) Journal of the American Medical Association 128, 189 Brown J W (1939) Congenital Heart Disease. John Bale Medical, London Crafoord C & Nylin G (1945) Journal of Thoracic Surgery 14, 347 Danielson G K (1978) In: Paediatric Cardiology 1977. Ed. R H Anderson and E A Shinebourne. Churchill Livingstone, Edinburgh; p 381 Farre J R (1814) Pathological Researches. Longman, London Gibbon J (1939) quoted by Wangenstein (1975) Gross R E (1939) Annals of Surgery 110, 321 Hamilton D I (1978) In: Paediatric Cardiology 1977. Eds. R H Anderson and E A Shinebourne. Churchill Livingstone, Edinburgh; p 388 Hamilton D I, Di Eusanio G, Sandrasagra F A & Donnelly R J (1978) Journal of Thoracic and Cardiovascular Surgery 75, 699 Hamilton D I, Shackleton J, Rees G J & Abbot T (1973) In: Heart Disease in Infancy, Diagnosis and Surgical Treatment. Ed. B G Barratt-Boyes, J M Neutze and E A Harris. Churchill Livingstone, Edinburgh; p 52 Lillehei C W (1975) In: Congenital Malformations of the Heart. Ed. D A Goor and C W Lillehei. Grune & Stratton, New York; p xv Melrose D G (1969) In: Medical and Surgical Cardiology. Ed. W Cleland, J Goodwin, et al. Blackwell, Oxford; p 315 McMichael J (1969) In: Cardiac Catheterization and Angiography. Ed. D Verel and R G Grainger. Livingstone, Edinburgh; p v Shinebourne E A, Tam A S Y, Elseed A M, Paneth M, Lennox S C, Cleland W P, Lincoln C, Joseph M C & Anderson R H (1976) British Heart Journal 38, 275 Taussig H B (1947) Congenital Malformations of the Heart. Commonwealth Fund, New York Wangenstein 0 H (1975) In: Congenital Malformations of the Heart. Ed. D A Goor and C W Lillehei. Grune & Stratton, New York; p xi
