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Transposition of the Great Vessels
1
TRANSPOSITION OF THE GREAT VESSELS
Diagnostic Considerations and Surgical Therapy
ROBERT A. MaLER, M.D. THOMAS G. BAFFES, M.D. ALBERT A. WILKINSON, JR., M.D.
The cyanotic child suspected of having a transposition of the great vessels presents a dual problem to the pediatrician. For, if the child has survived the first weeks of life, he has, in addition to the anomaly of the great vessels, a major intracardiac shunting lesion, usually a ventricular septal defect. Transposition of the aorta and pulmonary artery generally can be divided into three groups: (1) complete transposition, (2) partial transposition, and (3) Taussig-Bing complex. These conditions are believed to result from an abnormality in absorption of the bulbus of the embryo heart occurring about the fifth week of intrauterine life. There is probably abnormal ridge formation in the bulbus. The aorta arising from the right ventricle may represent the right ventricular aorta of the reptile; thus there may be a phylogenetic factor in the development of the transposition complex. The collection of abnormal hearts in the pathology section of The Children's Memorial Hospital contains 100 hearts with transposition of the great vessels. This excludes those complexes such as isolated dextrocardia, isolated levocardia and the so-called corrected transposiFrom the Department of Cardiology and Department of Surgery, The Children's Memorial Hospital, and the Department of Pediatrics, Northwestern University Medical School, Chicago. This work was partially supported by the Otho S. A. Sprague Memorial Foundation and the Chicago Heart Association.
1110
TRANSPOSITION OF THE GREAT VESSELS
tions. The most commonly encountered type of transposition complex is that of complete transposition, in which the aorta clearly arises anteriorly from the right ventricle and the pulmonary artery arises posteriorly from the left ventricle. This is present in 86 per cent of the specimens. In this situation the pulmonary artery is usually larger than the aorta. The coronary arteries in this as well as the other two types of transposition complexes arise from the aorta. In most instances of complete transposition there is a defect of the ventricular septum. This is most often located just below the pulmonary and aortic valve cusps, through the region of the pars membranacea. Less frequently, in 21 per cent of the cases there is a defect of the atrial septum or a patent ductus arteriosus (27 per cent). In 6 per cent of the cases there is total absence of the ventricular septum, the aorta and pulmonary artery arising in a transposed position from a common ventricle. In cases in which the pulmonary artery is smaller than the aorta, the pulmonary valve may be stenotic or atretic. In the latter situation there is usually a patent ductus arteriosus. Pulmonary stenosis is seen in 10 per cent of the hearts and pulmonary valvular atresia in 11 per cent. In the group with complete transposition, congenital mitral stenosis was present twice, and in one instance there was a vascular ring surrounding the trachea. The second most commonly encountered transposition complex is partial transposition, or double outlet right ventricle, in which the pulmonary artery and the aorta both arise from the right ventricle. This has occurred in 11 per cent of our postmortem cases. In this complex the right ventricle is large, and there is always a defect of the ventricular septum. Depending on its place of origin from the right ventricle, the pulmonary artery may be larger or smaller than the aorta. The most infrequent type of transposition complex is that originally described by Taussig and Bing and bears their name. In this complex (3 per cent of our cases) the pulmonary artery is located posteriorly and overrides the ventricular septum above a defect, while the aorta arises anteriorly in a position not related to the septal defect. At present the surgeon cannot approach the problem of malposition of the great vessels and that of the intra cardiac lesion at the same procedure; he therefore attacks the problem of the transposition of the great vessels and leaves the septal defect surgery for some future date. This situation affects the clinician, for he must select those patients for operation in whom the disability is due primarily to the transposed vessels and not to the intracardiac shunting lesion or to pulmonary vascular obstruction.
1
ROBERT A. MILLER, THOMAS G. BAFFES, ALBERT A. WILKINSON
1111
CLINICAL DIAGNOSIS
Transposition of the great vessels can usually be differentiated from other types of cyanotic congenital heart disease by clinical examination. The patient is usually deeply cyanotic, and there is a retardation of physical development. There is often wasting and atrophy of the tissues of the extremities associated with clubbing of the finger tips and the toes. As in other conditions associated with severe cyanosis, the head may have an enlarged, square appearance. The closure of the fontanels may be delayed. Some of our patients came in with a diagnosis of "congenital heart disease and possible hydrocephalus." Careful observation of the patterns of cyanosis is occasionally fruitful, because some children with transposition of the great vessels are noticeably more cyanotic in the upper half of the body than in the abdomen and lower extremities. This type of distribution of cyanosis is always associated with transposition of the great vessels and a patent ductus arteriosus with pulmonary hypertension. The pulmonary artery carrying oxygenated blood from the left ventricle may shunt blood through the ductus into the descending aorta. On auscultation the heart tones usually sound rather dynamic. The second sound is usually increased in intensity. The heart seems to be overworking; it is almost always enlarged, and there is often a precordial bulge. The murmur is that of an associated lesion, usually a fairly loud systolic murmur maximum in the third and fourth left interspaces near the sternum. This murmur is due to a ventricular septal defect. Occasionally a rather loud, harsh systolic murmur is heard best high on the precordium in the second left interspace to the right and left of the sternum. This murmur is usually due to pulmonary stenosis. Patients with transposition of the great vessels without a ventricular septal defect or pulmonary stenosis usually have no murmur. In other words, transposition of the great vessels with an atrial septal defect, a patent ductus, or both, has little else than dynamic heart tones on auscultation. The electrocardiogram almost always shows right ventricular hypertrophy, often of a severe type with S-TT changes suggesting ischemia. Evidence of left ventricular hypertrophy is not rare and is found in those cases in which there is a large pulmonary flow or in cases associated with pulmonary vascular obstruction or pulmonary stenosis. A patient with transposition of the great vessels with a large ventricular septal defect and low pulmonary vascular resistance may show left ventricular hypertrophy only on the electrocardiogram. A patient with transposition of the great vessels who has left ventricular hypertrophy on the electrocardiogram, therefore, does not necessarily have tricuspid atresia.
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TRANSPOSITION OF THE GREAT VESSELS
A F ig. 157. A, Transposition of th e grea t vessels with ventricular septal defect and low pulmonary vascular resistance in a male infant 6 months old . B, T en m onths after operation . The ao rtic h omograft is visualized as a fain t line of calcifica tion at the right carcliophrenic border.
A
B
Fig. 158. A, Transposition of th e grea t vessels in male infant 28 clays old in congestive cardiac failure. B, Six m onths after operation , which was perform ed at 6 weeks of age.
The x-ray picture usually shows an enlarged "egg-shaped" heart; the mediastinum appears to be narrow, and the vascular markings in the lung fields are usually increased. In summary, then, the cyanotic patient with an enlarged heart whose x-ray film shows increased vascularity of the lung fields and a narrow mediastinum usually has a transposition complex. The loud systolic
•
ROBERT A. MILLER, THOMAS G. BAFFES, ALBERT A. WILKINSON
1113
murmur heard in many of these patients is due to an associated ventricular septal defect or pulmonary stenosis. The intensely cyanotic infant without a murmur generally does not survive beyond the first weeks of life. Without a ventricular septal defect he is unable to get sufficient intracardiac mixing and sends almost pure venous blood out the aorta and highly oxygenated blood out the left ventricle to his lungs. Because this child has no other important lesion than transposition of the great vessels, he is potentially the ideal surgical candidate. However, during operation he must get along without the right lung, which must be clamped off during
B A Fig. 159. A, Transposition complex in a 5-year-old boy in severe congestive cardiac failure with anasarca. B, Six months after operation_ Note the increased pulmonary flow. This child had a ventricular septal defect and low pulmonary vascular resistance. Clinically, the child was strikingly improved, pink and active.
the procedure; the anesthetist must depend on the left lung, upon which lies a greatly enlarged heart. Thus, at present, the patient with no other lesion rarely survives operation. The selection of patients for the surgery of transposition of the great vessels is therefore largely limited to those with a ventricular septal defect. The following cases illustrate four commonly encountered types of transposition complexes. CASE LA 7-month-old infant has been cyanotic from birth. He has grown poorly, has had frequent respiratory infections and has been very irritable. Clinical examination shows clubbing of the fingers and toes. The cardiac apex is in the fifth left interspace at the nipple line. There is a grade III harsh systolic murmur heard best in the third and fourth left interspaces at the left sternal border. A thrill is palpable, and there is a grade II mid-diastolic murmur heard best at the apex. The electrocardiogram shows ,ight heart strain, even for a 7-month-old child. Roentgenograms show that the heart is moderately enlarged, the vascularity of the lung fields is increased, and the mediastinum is narrow.
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TRANSPOSITION OF THE GREAT VESSELS
Cardiac catheterization data are as follows: POSITION
OXYGEN
% SA TURA TION SVC .... .... 37.1 RA .... .... 36.0 RV .... · .... 37.1 RPA .. · .... 87.5 RPA .... · .... 86.1 FA .......... 38.9 RPA .......... 79.3 . .40.2 RV ... RA ... . .26.4 . .. 20.4 SVC .. ?LV .. PC ......... . (96.0)
OXYGEN CONTENT 5.9 5.7 5.9 13.8 13.6 6.1 12.5 6.3 4.2 3.2
OXYGEN CAPACITY
PRESSURES (MM. HG)
mean = 5 90-100/8
mean = 50
15.8 55/33
mean = 43
63/8 (15.2)
The oxygen saturation data obtained at the beginning of the study do not indicate any significant difference between the superior vena cava, right atrium and right ventricle samples. However, rapid sampling from these same chambers at the termination of the procedure does indicate a small left-to-right shunt at the ventricular level. The oxygen saturation of the femoral artery blood is almost identical with that from the right ventricle. The catheter was left in the right ventricle, and an angiocardiogram from this position indicated that the aorta was anterior, filling from the right ventricle. The pulmonary artery also was visualized via the right-to-left shunt. This child has a transposition of the great vessels with a ventricular septal defect and low pulmonary vascular resistance. As a consequence, he has little left-to-right shunting, but a considerable right-to-left shunting. He has an increased pulmonary /low, but he is intensely cyanotic-an ideal surgical candidate for a "vessel transplant" type of operation.
A patient with transposition plus a ventricular septal defect who does show a large left-to-right shunt at the ventricular level should be carefully evaluated for surgery. The large left-to-right shunt is usually due to increased left ventricular pressure. The basis for this may be pulmonary stenosis or increased pulmonary vascular resistance. Because the latter group of patients are poor surgical candidates, it is important to identify them. Generally speaking, these patients can be separated by clinical criteria_ The patient with pulmonary stenosis is somewhat less cyanotic than the usual patient with a transposition and gets along better clinically. The pulmonary stenosis raises his left ventricular pressure, and a fair-sized amount of oxygenated blood is shunted left to right into the aorta_ He usually has a loud, systolic murmur maximum high on the precordium in the second left interspace, but occasionally in the second right interspace. A thrill is usually palpable, and the second sound is rather quiet. The electrocardiogram may show a combined heart strain (the left ventricle is contracting against a resistance load) . The following case illustrates this type of patient. CASE II. This 7-year-old child has been cyanotic since birth. (Note that she has survived longer than the usual transposition patient.) She has always developed poorly and is extremely limited in her physical activity. On physical examination she is somewhat underdeveloped, with cyanosis and clubbing of the fingers and toes_ The cardiac
l
ROBERT A. MILLER, THOMAS G. BAFFES, ALBERT A. WILKINSON
1115
ilpex is in the fifth left interspace in the nipple line. There is a grade IV harsh systolic murmur best heard at both the second and third interspaces along the right sternal border and also well heard over the sternum. There is a thrill over the precordium probably maximum at the upper right sternal border, but also felt well at the left sternal border. The second sound is decreased in intensity in the second interspace, but loud and unsplit in the fourth left and right interspaces. There is no diastolic murmur. The electrocardiogram shows large peaked P waves and right-sided heart strain. The roentgenogram showed moderate cardiac enlargement, slight increase in the vascularity of the ~ung fields and a narrow mediastinum. Cardiac catheterization data are as follows: A no. 6 catheter was passed into the right saphenous vein, the inferior vena cava, right atrium, and superior vena cava. From the right atrium the catheter was manipulated into the left atrium and into the left ventricle_ The catheter was allowed to loop in the left ventricle and was manipulated out the pulmonary artery. It was withdrawn and then passed from the right atrium to the right ventricle and out the pulmonary artery again, this time from the right side. The catheter was left at the apex of the right ventricle and a selective angiocardiogram was performed with 15 cc. of Hypaque. POSITION
OXYGEN
OXYGEN
OXYGEN
PRESSURES
% SATU-
CONTENT
CAPACITY
(MM_ HG)
RATION
IVC ........... 59.4 RA mI ........... 55.6 SVC ........... 56.7 LV ........... 92.9 FA ........... 71. 9 LV* ...... 93.8,93.8 FA ...... 69.7,67.5 MPA ........... 89.1 PC wedge .......... 100. LA ........... 96.7 RV ........... 70.8 RPA ........... 93.5 LPV .......... 100.
at right atrial
level
15.2
19.0
27.3
107/5? 99/65 21/8
129/9? mean = 77 mean = 15 mean =
2
101/3 25.5 27.3
A-V
Flow/M2
Systemic ....... 3 . 8 Pulmonary ....... 1 .8 Erf. Pulmonary ....... 2.1
Estimated 4.5 9.6 1.4
Resistance Units/M2 16.6 1.3 MPA pressure 15 mm. Hg = 200 mm. H 20
The oxygen saturation data show essentially the same saturation in the superior vena cava, right atrium, and inferior vena cava; there is a left-to-right shunt at the ventricular level, an increase in oxygen saturation from 56 per cent in the atrium to 71 per cent in the right ventricle. Simultaneous samples from the right ventricle and femoral artery indicate that the systemic artery saturation is essentially identical with the right ventricular samples. The pulmonary artery entered from the right ventricle has a saturation of 90 per cent, in good agreement with the samples obtained from the left atrium, left ventricle and the pulmonary artery entered from the left ventricle. Thus the data show good evidence of transposition of the great vessels with a ventricular septal defect and suggest that the pulmonary artery overrides the ventricular septal defect. On withdrawing the catheter from the pulmonary artery into either ventricle, a large gradient of pressure is noted, establishing the diagnosis of pulmonary stenosis. The angiocardiogram illustrates a transposed aorta coming off anteriorly from the right ventricle and faint early filling of the pulmonary arteries. The estimated pulmonary blood flow in this patient is approximately twice the systemic flow, and the pulmonary vascular resistance is low. Despite the pulmonary stenosis, the patient has good pul-
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TRANSPOSITION OF THE GREAT VESSELS
monary flow, and her femoral artery saturation is only 70 per cent. She is a good candidate for a "vessel transplant" type of operation.
The patient with transposition of the great vessels with a large leftto-right shunt at the ventricular level and high pulmonary vascular resistance probably should not be operated upon at present. The following case illustrates a patient of this type. CASE III. This ll-year-old girl was first noted to be cyanotic about 2 years of age. (Again note that she is an older patient.) Her physical activity is limited. She becomes dyspneic on moderate exertion, but she has never had any fainting spells. On physical examination she is moderately cyanotic, fairly well developed, and well nourished. There is slight prominence of the left chest. There is a right ventricular impulse at the xiphoid. There is a grade III soft systolic murmur loudest in the third left interspace, and a definite early systolic click. There is a mid-diastolic murmur maximum at the apex. Both the first and second heart sounds are palpable. The electrocardiogram shows peaked P waves, incomplete right bundle branch block and right ventricular hypertrophy. A previous angiocardiogram demonstrated an anterior aorta, a simultaneously visualized pulmonary artery and suggestive revisualization of a pulmonary artery from the left ventricle. Catheterization data are as follows: A no. 6 catheter was inserted into the right median antecubital vein. It entered the right superior vena cava, right atrium and the right ventricle. In the right ventricle the catheter was manipulated to enter a great vessel arising near the midline, which was interpreted as being the pulmonary artery, but it was not possible to get out into the lung fields. POSITION
OXYGEN
OXYGEN
SATURATION
CONTENT
BA* ......... 79.3 Great vessel ......... 87.5 BA* ......... 76.8 Great vessel ......... 86.1 RVoutflow ......... 86.4 RV inflow ......... 85.8 RA .... 65.8,65.6 SVC .... 64.8,65.8 PC ......... (98)
22.1 23.6
CAPACITY
PRESSURES (MM. HG)
27.0
110/75 110/60
mean mean
= 82 = 82
mean
= 10
105/8 23.0 17.7 (26.4)
BSA ......... 1.46 M2 O 2 Consumption (251 ml./min.) assumed Estimations (based on assumption great vessel is pulmonary artery): Systemic flow L/min ......... 5.7 Pulmonary flow L/min ......... 9.0 Effective pulmonary flow. . . . . . . . 2 . 9
3.9 L/min./M2
Left-to-right shunt L/min ...................... 3. 3 Right-to-Ieft shunt L/min ...................... 2.9 Systemic resistance ..................... 18 units Pulmonary resistance ..................... 12 units
* Simultaneous. The oxygen saturation data indicate a large left-to-right shunt at the ventricular level. There is a jump in oxygen content of about 5 volumes per cent from the right atrium to the right ventricle. Simultaneous sampling from the brachial artery and the pulmonary artery consistently showed a higher concentration of oxygen in the pulmonary artery than in the brachial artery. The mean pressures in the pulmonary artery and the brachial artery were essentially identical, but the diastolic level in the pulmonary artery was consistently lower. Based on the assumption that the great vessel entered is the pulmonary artery, the pulmonary vascular resistance is increased.
ROBERT A. MILLER, THOMAS G. BAFFES, ALBERT A. WILKINSON
This patient with her peripheral oxygen saturation approximately 80 per cent is not a candidate for current operations for transposition of the great vessels. Her disability is not due primarily to a transposed aorta getting venous blood from the right ventricle. She already has considerable intracardiac shunting, and her disability is, to a large degree, due to pulmonary vascular obstruction.
Thus far we have illustrated two types of cases in which we feel operation is indicated and one in which it probably is not. The fourth case is presented because a surgical decision is not easy to make. A transposition complex in which both great vessels arise from the right ventricle, the so-called double outlet right ventricle complex, is not rare. This anomaly occurs in 11 per cent of our postmortem cases. In these children the aorta is completely transposed, and there is a large ventricular septal defect. The pulmonary artery, however, arises entirely from the right ventricle, or is only slightly levoposed. CASE IV. This 2-year-old boy has been moderately cyanotic from birth. He has grown and developed moderately weH, but definitely tires more easily than other children his age. He breathes hard on exertion, and his cyanosis increases upon crying or when he is tired. At rest, however, he has only mild cyanosis of the lips and fingernails. Cardiac catheterization was carried out via the right saphenous vein, and the catheter was passed into the inferior and superior venae cavae, the right atrium and the right ventricle. On manipulation in the right ventricle the catheter could be passed into both the aorta and the pulmonary artery. In fact, the path of the catheter from the ventricle out the pulmonary artery seemed almost the same as in the normal heart. One could almost feel a crista, being assured of going into the pulmonary artery when the catheter tip was to the right of it or into the aorta when the catheter tip was to the left of it. After blood samples and pressures had been recorded a cine-angiocardiogram was done with the catheter in the right ventricle. Cardiac catheterization data are as foHows: POSITION
OXYGEN
OXYGEN
OXYGEN
PRESSURES
%SATU-
CONTENT
CAPACITY
(MM. HG)
RATION
SVC .... .47.5,51.5 RA .......... 54.2 RV outflow .......... 74.9 {AO .......... 69.7 Ao .......... 70.8 FA .......... 68.4 FA .......... 61.2 PA .......... 89.9 PA .......... 86.4 {FA .......... 71.1 PA .......... 90.4 RV .......... 77.1 RA ..... . .52.8 SVC .... ... 48.2 {PA ...... .. . 85.0 FA ...... ... 70.2 PC .......... (96.0) A-V
Systemic .... . ... 6.1 Pulmonary .......... 2 . 5
11.6 12.2 16.9 22.5 15.9 15.4
100/62 94/60
90/60 90/10 11.9 19.1 15.8 21. 6
Flow/M2 2.8 6.9
Resistance moderately elevated minimum about 6 units
mean = 70 mean = 70
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TRANSPOSITION OF THE GREAT VESSELS
The oxygen saturation data indicate that there is a large left-to-right shunt at the ventricular level. The oxygen saturation of blood samples obtained simultaneously from the pulmonary artery and femoral artery show that the pulmonary artery sample was repeatedly higher in oxygen saturation. The systolic blood pressure levels in the pulmonary artery, right ventricle, femoral artery and aorta were all within 5 mm. of each other. The cine-angiocardiogram shows both the aorta and pulmonary artery filling equally well and simultaneously from the right ventricle. The iStimated pulmonary resistance in this patient is moderately elevated, and the pulmonary flow is about two and one-half times the systemic flow. This child has a large heart and increased vascularity of the lung fields. Although his oxygen saturation is 70 per cent, he is definitely not as cyanotic as the usual patient with a transposition complex, and his growth and development has been fairly good. Although operation would improve him and would raise his peripheral oxygen saturation about 15 per cent, it would seem that his intracardiac pathology is such that it might be more prudent to delay operation, awaiting future surgical progress.
The foregoing may be summarized as follows: Present-day surgery for transposition of the great vessels is directed at sending more oxygenated blood out the aorta and directing the venous blood to the left side of the heart so that it will go out the pulmonary artery. Therefore the best candidates for surgery are the children who are most intensely cyanotic. For the child with a transposition complex who is not very cyanotic the risk of these operative procedures may not be warranted. The lack of intense cyanosis indicates that the child already has a considerable left-to-right shunt. The cause of a large left-to-right shunt is usually either pulmonary vascular obstruction or pulmonary stenosis. These children with a transposition of the great vessels, ventricular septal defect and mild pulmonary stenosis have been improved by present-day surgery. Those patients with a large left-toright shunt and evidence of high pulmonary vascular resistance have had a high mortality rate. Surgery is probably contraindicated for them at present. The most gratifying results from the Baffes type of procedure for transposition of the great vessels have been obtained in those children whose peripheral oxygen saturation has been between 35 and 70 per cent. SURGICAL CORRECTION OF TRANSPOSITION OF THE GREAT VESSELS
Transposition of the aorta and the pulmonary artery remains one of the greatest challenges to the cardiovascular surgeon. Surgical correction in the past included the addition of shunting devices between the pulmonary artery and the systemic circulation, attempts to convert the transposition to an operative tetralogy, attempts at transplanting the aorta and pulmonary artery back to the proper ventricle, and transplanting of the major veins of the heart, in order to compensate for the defect. The present operation at the Children's Memorial Hospital represents one of the latter types of operation.
ROBERT A. MILLER, THOMAS G. BAFFES, ALBERT A. WILKINSON
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The surgical patient is placed in the left lateral decubitus position, and the right hemithorax is opened. The lung is retracted downward. The right main pulmonary artery is isolated and temporarily ligated.in order to prevent pulmonary congestion. Prior to occluding the pulmonary artery the pressure is determined on the water manometer. If the pulmonary artery is small and collapsed and if the pressure in it is low, a subclavian pulmonary anastomosis is performed. If there is an adequate-sized pulmonary artery with the "feel" of adequate flow through it, the transplantation of the pulmonary veins and inferior vena cava is carried out. (1) A curved coarctation clamp is placed on the lateral aspect of the inferior vena cava in such a way that the flow of blood from the inferior vena cava into the right atrium is not occluded (Fig. 160, B, C). An incision is made in the excluded lip of the inferior vena cava, and a homologous aortic graft is anastomosed to the incision. (2) The right main stem bronchus is occluded with a temporary umbilical tape ligature, and the right pulmonary veins are divided from their point of entry into the left atrium. The distal end of the pulmonary veins is left open in order to avoid any hemorrhagic pulmonary congestion (Fig. 160, D, E). (3) The opposite end of the homologous aortic graft is then anastomosed to the left atrial stump of the pulmonary veins (Fig. 160, F). (4) A curved coarctation clamp is then applied to the lateral aspect of the right atrium, and the distal end of the pulmonary veins is anastomosed to the excluded wall of the right atrium (Fig. 160, F, G). (5) After completion of all the anastomoses the temporary occluding ligatures about the right main pulmonary artery and the right main stem bronchus are removed, and the patient is allowed a few minutes to become stable. (6) A no. 1 silk ligature is then placed about the inferior vena cava at its point of entry into the right atrium. This makes the flow of blood from the inferior vena cava through the homologous graft and into the left atrium obligatory. This method achieves transfer of approximately 60 per cent of the systemic venous return to the left atrium, from which it is eventually ejected into the pulmonary circuit, and 60 per cent of the pulmonary venous return into the right atrium, from which it eventually reaches the systemic circulation. Results
Sixy-seven patients have been operated upon by the technique described above, by various members of the surgical staff of The TABLE
23. Mortality Rate According to Age AGE GROUP
TOTAL CASES
SURVIVORS
DEATHS
MORTALITY RATE
71.4% 18.1 % 33.3% 38.8%
0-6 months. . . . . .. . .. 14 . 11 7 months-l year. . . . . . . Over 1 year ........... 42
28
10 2 14
Totals ........... 67
41
26
4 9
Children's Memorial Hospital. Twenty-six patients died at operation or in the immediate postoperative period, an operative mortality rate of 38.8 per cent. Forty patients survived the operation and were sent home, a survival rate of 60.6 per cent. Four of these patients died subsequently of pulmonary arteriosclerosis, intercurrent infection or other causes unrelated to the operative procedure (Table 23). In general, the surviving patients have shown satisfactory improvement in their cyanosis and increase in exercise tolerance. Preoperatively the patients had oxygen saturations ranging from 35 to 50 per
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TRANSPOSITION OF THE GREAT VESSELS
Tape around
t'iS/fIt: phreriC nerve I
I
/ - Intet'att'ial
RiQht
sulcus
pulmon.veina ____ Aortic S1\"dft suturedto IY.C.
Fig. 160. Steps in surgical correction of transposition of great vessels. (T. C. Baffes, W. A. Riker, A. DeBoer and W. J. Potts: Surgical Correction of Transposition of the Aorta and the Pulmonary Artery. J. Thoracic Surg., Vol. 34.)
cent of capacity. They had poor exercise tolerance, many of them being unable to walk or bear weight. Many were in frank congestive cardiac failure. Postoperatively the patient's color improved rather promptly, and by about two to three weeks postoperatively the oxygen saturation had risen to approximately 85 per cent. Within six to eight weeks after operation the patients showed increase in exercise tolerance, the muscle mass of the calves and thighs increased, and soon active ambulation was possible. The liver decreased in size, and the ascites disappeared. On x-ray examination of the chest a number of these patients showed a decrease in heart size. Many patients showed only a trace of cyanosis at rest. Analysis of Mortality Rates and Survivals
The youngest patient successfully operated on with this technique was six weeks old at the time of operation. The oldest was 12 years old. From an analysis of the mortality statistics based on age, the
ROBERT A. MILLER, THOMAS G. BAFFES, ALBERT A. WILKINSON
D
line of divisiOn of right pulm.
1121
Retractor
veins /
/
/
I
Right pu1m.veins
Fig. 160 (continued)
best time for this operation to be performed is some time after the age of six months, provided the patient does not deteriorate before he reaches that age. If deterioration occurs earlier, prompt operation should be done, since the condition usually is progressive and significantly alters mortality rate. Fourteen patients were operated upon at less than six months of age (Table 23). Ten died in the immediate postoperative period, a mortality rate of 71.4 per cent. Two of the four survivors, however, were in the newborn period, aged six weeks and seven weeks respectively. Eleven patients were operated upon at ages ranging from seven months to one year. Only two succumbed in the immediate postoperative period, a mortality rate of 18.1 per cent. The surviving patients in this age group gave some of the most striking clinical results. Forty-two patients were operated upon at ages over one year. Most of these were between three and five years of age. Fourteen patients died in the immediate postoperative period, an operative mortality
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TRANSPOSITION OF THE GREAT VESSELS
rate of 33.3 per cent. This age group offered a particular advantage in that they were large enough to permit introduction of a rnaximumsized homograft between the inferior vena cava and the left atrium, thereby eliminating the danger that subsequent growth of the child might render the size of the homograft inadequate for draining the lower part of the body. On the other hand, this danger has not materialized in the younger children who by now have been followed up over three years. Their azygos vein was left intact, and adequate collateral circulation has apparently kept pace with the patient's growth. Analysis of the causes of death is also illuminating. A number of these operative deaths were entirely technical and therefore can be prevented. As shown in Table 24, 14 patients died of acute congestive TABLE
24. Analysis of Causes of Operative and Delayed Mortality
Immediate operative deaths: Acute congestive failure. Cardiac arrest. Supraventricular tachycardia. Cerebrovascular accidents. Right pulmonary edema with anoxia. Hemorrhage from right lung, with congestion. Intercostal hemorrhage. Total.
... ... ... ... ... ... ... .
. . . . . . .
.. .. .. .. .. .. ..
.. 5 . .. ......... 4 .. 1 . 4 .. 5 .. . . .. 5 ........... 2 . ........... 26
Delayed deaths: Diarrhea ......... ' Pneumonitis. . . . . . . . . Pulmonary arteriosclerosis. . . . . . . . . Total. . . . . . . . .. . .. ....
1 1 2 4
failure, cardiac arrest during the procedure, or cerebral vascular accidents during or after operation. Generally, these events occurred in severely deteriorated patients and may be considered unavoidable. However, 10 operative deaths resulted from hemorrhagic congestion of the right lung or right pulmonary edema with anoxia. Most of these deaths occurred in the youngest age group and resulted either from insufficient control of the high pulmonary artery pressure during the operative procedure, or from attachment of the right pulmonary veins to the right atrium at too sharp an angle, resulting in partial obstruction of drainage of the right lung. More recently, with particular care in the handling and control of the right lung, these complications have been reduced. Four deaths occurred after the patients had been discharged from the hospital and were unrelated to the operative procedure. One patient died of pneumonitis. One patient died of severe Salmonella infection. Two others expired of episodes that were interpreted as pneumonitis, but at autopsy showed severe, far-advanced pulmonary arteriosclerosis.
ROBERT A. MILLER, THOMAS G. BAFFES, ALBERT A. WILKINSON
1123
SUMMARY
Although the operation described above has produced dramatic improvement in many of our patients with transposition of the great vessels, it is obviously not the final answer to this serious problem. The clinician does not advise operation merely because a procedure is now available. The patient is operated upon because he is severely handicapped and because his prognosis without operation is very poor. The high mortality rate of to-day's major cardiac procedures must be justified by proper selection of patients. Unless there is good reason to expect a great improvement in the patient's condition after operation, the risk may not be justified. Since the great majority of children with transposition of the great vessels die in the first year or two of life, an operation of this type, even though it only partially corrects the malformation, is a step in the right direction. 707 Fullerton Avenue Chicago 14, Illinois
TRANSPOSITION OF THE GREAT VESSELS
Diagnostic Considerations and Surgical Therapy
ROBERT A. MaLER, M.D. THOMAS G. BAFFES, M.D. ALBERT A. WILKINSON, JR., M.D.
The cyanotic child suspected of having a transposition of the great vessels presents a dual problem to the pediatrician. For, if the child has survived the first weeks of life, he has, in addition to the anomaly of the great vessels, a major intracardiac shunting lesion, usually a ventricular septal defect. Transposition of the aorta and pulmonary artery generally can be divided into three groups: (1) complete transposition, (2) partial transposition, and (3) Taussig-Bing complex. These conditions are believed to result from an abnormality in absorption of the bulbus of the embryo heart occurring about the fifth week of intrauterine life. There is probably abnormal ridge formation in the bulbus. The aorta arising from the right ventricle may represent the right ventricular aorta of the reptile; thus there may be a phylogenetic factor in the development of the transposition complex. The collection of abnormal hearts in the pathology section of The Children's Memorial Hospital contains 100 hearts with transposition of the great vessels. This excludes those complexes such as isolated dextrocardia, isolated levocardia and the so-called corrected transposiFrom the Department of Cardiology and Department of Surgery, The Children's Memorial Hospital, and the Department of Pediatrics, Northwestern University Medical School, Chicago. This work was partially supported by the Otho S. A. Sprague Memorial Foundation and the Chicago Heart Association.
1110
TRANSPOSITION OF THE GREAT VESSELS
tions. The most commonly encountered type of transposition complex is that of complete transposition, in which the aorta clearly arises anteriorly from the right ventricle and the pulmonary artery arises posteriorly from the left ventricle. This is present in 86 per cent of the specimens. In this situation the pulmonary artery is usually larger than the aorta. The coronary arteries in this as well as the other two types of transposition complexes arise from the aorta. In most instances of complete transposition there is a defect of the ventricular septum. This is most often located just below the pulmonary and aortic valve cusps, through the region of the pars membranacea. Less frequently, in 21 per cent of the cases there is a defect of the atrial septum or a patent ductus arteriosus (27 per cent). In 6 per cent of the cases there is total absence of the ventricular septum, the aorta and pulmonary artery arising in a transposed position from a common ventricle. In cases in which the pulmonary artery is smaller than the aorta, the pulmonary valve may be stenotic or atretic. In the latter situation there is usually a patent ductus arteriosus. Pulmonary stenosis is seen in 10 per cent of the hearts and pulmonary valvular atresia in 11 per cent. In the group with complete transposition, congenital mitral stenosis was present twice, and in one instance there was a vascular ring surrounding the trachea. The second most commonly encountered transposition complex is partial transposition, or double outlet right ventricle, in which the pulmonary artery and the aorta both arise from the right ventricle. This has occurred in 11 per cent of our postmortem cases. In this complex the right ventricle is large, and there is always a defect of the ventricular septum. Depending on its place of origin from the right ventricle, the pulmonary artery may be larger or smaller than the aorta. The most infrequent type of transposition complex is that originally described by Taussig and Bing and bears their name. In this complex (3 per cent of our cases) the pulmonary artery is located posteriorly and overrides the ventricular septum above a defect, while the aorta arises anteriorly in a position not related to the septal defect. At present the surgeon cannot approach the problem of malposition of the great vessels and that of the intra cardiac lesion at the same procedure; he therefore attacks the problem of the transposition of the great vessels and leaves the septal defect surgery for some future date. This situation affects the clinician, for he must select those patients for operation in whom the disability is due primarily to the transposed vessels and not to the intracardiac shunting lesion or to pulmonary vascular obstruction.
1
ROBERT A. MILLER, THOMAS G. BAFFES, ALBERT A. WILKINSON
1111
CLINICAL DIAGNOSIS
Transposition of the great vessels can usually be differentiated from other types of cyanotic congenital heart disease by clinical examination. The patient is usually deeply cyanotic, and there is a retardation of physical development. There is often wasting and atrophy of the tissues of the extremities associated with clubbing of the finger tips and the toes. As in other conditions associated with severe cyanosis, the head may have an enlarged, square appearance. The closure of the fontanels may be delayed. Some of our patients came in with a diagnosis of "congenital heart disease and possible hydrocephalus." Careful observation of the patterns of cyanosis is occasionally fruitful, because some children with transposition of the great vessels are noticeably more cyanotic in the upper half of the body than in the abdomen and lower extremities. This type of distribution of cyanosis is always associated with transposition of the great vessels and a patent ductus arteriosus with pulmonary hypertension. The pulmonary artery carrying oxygenated blood from the left ventricle may shunt blood through the ductus into the descending aorta. On auscultation the heart tones usually sound rather dynamic. The second sound is usually increased in intensity. The heart seems to be overworking; it is almost always enlarged, and there is often a precordial bulge. The murmur is that of an associated lesion, usually a fairly loud systolic murmur maximum in the third and fourth left interspaces near the sternum. This murmur is due to a ventricular septal defect. Occasionally a rather loud, harsh systolic murmur is heard best high on the precordium in the second left interspace to the right and left of the sternum. This murmur is usually due to pulmonary stenosis. Patients with transposition of the great vessels without a ventricular septal defect or pulmonary stenosis usually have no murmur. In other words, transposition of the great vessels with an atrial septal defect, a patent ductus, or both, has little else than dynamic heart tones on auscultation. The electrocardiogram almost always shows right ventricular hypertrophy, often of a severe type with S-TT changes suggesting ischemia. Evidence of left ventricular hypertrophy is not rare and is found in those cases in which there is a large pulmonary flow or in cases associated with pulmonary vascular obstruction or pulmonary stenosis. A patient with transposition of the great vessels with a large ventricular septal defect and low pulmonary vascular resistance may show left ventricular hypertrophy only on the electrocardiogram. A patient with transposition of the great vessels who has left ventricular hypertrophy on the electrocardiogram, therefore, does not necessarily have tricuspid atresia.
1112
TRANSPOSITION OF THE GREAT VESSELS
A F ig. 157. A, Transposition of th e grea t vessels with ventricular septal defect and low pulmonary vascular resistance in a male infant 6 months old . B, T en m onths after operation . The ao rtic h omograft is visualized as a fain t line of calcifica tion at the right carcliophrenic border.
A
B
Fig. 158. A, Transposition of th e grea t vessels in male infant 28 clays old in congestive cardiac failure. B, Six m onths after operation , which was perform ed at 6 weeks of age.
The x-ray picture usually shows an enlarged "egg-shaped" heart; the mediastinum appears to be narrow, and the vascular markings in the lung fields are usually increased. In summary, then, the cyanotic patient with an enlarged heart whose x-ray film shows increased vascularity of the lung fields and a narrow mediastinum usually has a transposition complex. The loud systolic
•
ROBERT A. MILLER, THOMAS G. BAFFES, ALBERT A. WILKINSON
1113
murmur heard in many of these patients is due to an associated ventricular septal defect or pulmonary stenosis. The intensely cyanotic infant without a murmur generally does not survive beyond the first weeks of life. Without a ventricular septal defect he is unable to get sufficient intracardiac mixing and sends almost pure venous blood out the aorta and highly oxygenated blood out the left ventricle to his lungs. Because this child has no other important lesion than transposition of the great vessels, he is potentially the ideal surgical candidate. However, during operation he must get along without the right lung, which must be clamped off during
B A Fig. 159. A, Transposition complex in a 5-year-old boy in severe congestive cardiac failure with anasarca. B, Six months after operation_ Note the increased pulmonary flow. This child had a ventricular septal defect and low pulmonary vascular resistance. Clinically, the child was strikingly improved, pink and active.
the procedure; the anesthetist must depend on the left lung, upon which lies a greatly enlarged heart. Thus, at present, the patient with no other lesion rarely survives operation. The selection of patients for the surgery of transposition of the great vessels is therefore largely limited to those with a ventricular septal defect. The following cases illustrate four commonly encountered types of transposition complexes. CASE LA 7-month-old infant has been cyanotic from birth. He has grown poorly, has had frequent respiratory infections and has been very irritable. Clinical examination shows clubbing of the fingers and toes. The cardiac apex is in the fifth left interspace at the nipple line. There is a grade III harsh systolic murmur heard best in the third and fourth left interspaces at the left sternal border. A thrill is palpable, and there is a grade II mid-diastolic murmur heard best at the apex. The electrocardiogram shows ,ight heart strain, even for a 7-month-old child. Roentgenograms show that the heart is moderately enlarged, the vascularity of the lung fields is increased, and the mediastinum is narrow.
1114
TRANSPOSITION OF THE GREAT VESSELS
Cardiac catheterization data are as follows: POSITION
OXYGEN
% SA TURA TION SVC .... .... 37.1 RA .... .... 36.0 RV .... · .... 37.1 RPA .. · .... 87.5 RPA .... · .... 86.1 FA .......... 38.9 RPA .......... 79.3 . .40.2 RV ... RA ... . .26.4 . .. 20.4 SVC .. ?LV .. PC ......... . (96.0)
OXYGEN CONTENT 5.9 5.7 5.9 13.8 13.6 6.1 12.5 6.3 4.2 3.2
OXYGEN CAPACITY
PRESSURES (MM. HG)
mean = 5 90-100/8
mean = 50
15.8 55/33
mean = 43
63/8 (15.2)
The oxygen saturation data obtained at the beginning of the study do not indicate any significant difference between the superior vena cava, right atrium and right ventricle samples. However, rapid sampling from these same chambers at the termination of the procedure does indicate a small left-to-right shunt at the ventricular level. The oxygen saturation of the femoral artery blood is almost identical with that from the right ventricle. The catheter was left in the right ventricle, and an angiocardiogram from this position indicated that the aorta was anterior, filling from the right ventricle. The pulmonary artery also was visualized via the right-to-left shunt. This child has a transposition of the great vessels with a ventricular septal defect and low pulmonary vascular resistance. As a consequence, he has little left-to-right shunting, but a considerable right-to-left shunting. He has an increased pulmonary /low, but he is intensely cyanotic-an ideal surgical candidate for a "vessel transplant" type of operation.
A patient with transposition plus a ventricular septal defect who does show a large left-to-right shunt at the ventricular level should be carefully evaluated for surgery. The large left-to-right shunt is usually due to increased left ventricular pressure. The basis for this may be pulmonary stenosis or increased pulmonary vascular resistance. Because the latter group of patients are poor surgical candidates, it is important to identify them. Generally speaking, these patients can be separated by clinical criteria_ The patient with pulmonary stenosis is somewhat less cyanotic than the usual patient with a transposition and gets along better clinically. The pulmonary stenosis raises his left ventricular pressure, and a fair-sized amount of oxygenated blood is shunted left to right into the aorta_ He usually has a loud, systolic murmur maximum high on the precordium in the second left interspace, but occasionally in the second right interspace. A thrill is usually palpable, and the second sound is rather quiet. The electrocardiogram may show a combined heart strain (the left ventricle is contracting against a resistance load) . The following case illustrates this type of patient. CASE II. This 7-year-old child has been cyanotic since birth. (Note that she has survived longer than the usual transposition patient.) She has always developed poorly and is extremely limited in her physical activity. On physical examination she is somewhat underdeveloped, with cyanosis and clubbing of the fingers and toes_ The cardiac
l
ROBERT A. MILLER, THOMAS G. BAFFES, ALBERT A. WILKINSON
1115
ilpex is in the fifth left interspace in the nipple line. There is a grade IV harsh systolic murmur best heard at both the second and third interspaces along the right sternal border and also well heard over the sternum. There is a thrill over the precordium probably maximum at the upper right sternal border, but also felt well at the left sternal border. The second sound is decreased in intensity in the second interspace, but loud and unsplit in the fourth left and right interspaces. There is no diastolic murmur. The electrocardiogram shows large peaked P waves and right-sided heart strain. The roentgenogram showed moderate cardiac enlargement, slight increase in the vascularity of the ~ung fields and a narrow mediastinum. Cardiac catheterization data are as follows: A no. 6 catheter was passed into the right saphenous vein, the inferior vena cava, right atrium, and superior vena cava. From the right atrium the catheter was manipulated into the left atrium and into the left ventricle_ The catheter was allowed to loop in the left ventricle and was manipulated out the pulmonary artery. It was withdrawn and then passed from the right atrium to the right ventricle and out the pulmonary artery again, this time from the right side. The catheter was left at the apex of the right ventricle and a selective angiocardiogram was performed with 15 cc. of Hypaque. POSITION
OXYGEN
OXYGEN
OXYGEN
PRESSURES
% SATU-
CONTENT
CAPACITY
(MM_ HG)
RATION
IVC ........... 59.4 RA mI ........... 55.6 SVC ........... 56.7 LV ........... 92.9 FA ........... 71. 9 LV* ...... 93.8,93.8 FA ...... 69.7,67.5 MPA ........... 89.1 PC wedge .......... 100. LA ........... 96.7 RV ........... 70.8 RPA ........... 93.5 LPV .......... 100.
at right atrial
level
15.2
19.0
27.3
107/5? 99/65 21/8
129/9? mean = 77 mean = 15 mean =
2
101/3 25.5 27.3
A-V
Flow/M2
Systemic ....... 3 . 8 Pulmonary ....... 1 .8 Erf. Pulmonary ....... 2.1
Estimated 4.5 9.6 1.4
Resistance Units/M2 16.6 1.3 MPA pressure 15 mm. Hg = 200 mm. H 20
The oxygen saturation data show essentially the same saturation in the superior vena cava, right atrium, and inferior vena cava; there is a left-to-right shunt at the ventricular level, an increase in oxygen saturation from 56 per cent in the atrium to 71 per cent in the right ventricle. Simultaneous samples from the right ventricle and femoral artery indicate that the systemic artery saturation is essentially identical with the right ventricular samples. The pulmonary artery entered from the right ventricle has a saturation of 90 per cent, in good agreement with the samples obtained from the left atrium, left ventricle and the pulmonary artery entered from the left ventricle. Thus the data show good evidence of transposition of the great vessels with a ventricular septal defect and suggest that the pulmonary artery overrides the ventricular septal defect. On withdrawing the catheter from the pulmonary artery into either ventricle, a large gradient of pressure is noted, establishing the diagnosis of pulmonary stenosis. The angiocardiogram illustrates a transposed aorta coming off anteriorly from the right ventricle and faint early filling of the pulmonary arteries. The estimated pulmonary blood flow in this patient is approximately twice the systemic flow, and the pulmonary vascular resistance is low. Despite the pulmonary stenosis, the patient has good pul-
1116
TRANSPOSITION OF THE GREAT VESSELS
monary flow, and her femoral artery saturation is only 70 per cent. She is a good candidate for a "vessel transplant" type of operation.
The patient with transposition of the great vessels with a large leftto-right shunt at the ventricular level and high pulmonary vascular resistance probably should not be operated upon at present. The following case illustrates a patient of this type. CASE III. This ll-year-old girl was first noted to be cyanotic about 2 years of age. (Again note that she is an older patient.) Her physical activity is limited. She becomes dyspneic on moderate exertion, but she has never had any fainting spells. On physical examination she is moderately cyanotic, fairly well developed, and well nourished. There is slight prominence of the left chest. There is a right ventricular impulse at the xiphoid. There is a grade III soft systolic murmur loudest in the third left interspace, and a definite early systolic click. There is a mid-diastolic murmur maximum at the apex. Both the first and second heart sounds are palpable. The electrocardiogram shows peaked P waves, incomplete right bundle branch block and right ventricular hypertrophy. A previous angiocardiogram demonstrated an anterior aorta, a simultaneously visualized pulmonary artery and suggestive revisualization of a pulmonary artery from the left ventricle. Catheterization data are as follows: A no. 6 catheter was inserted into the right median antecubital vein. It entered the right superior vena cava, right atrium and the right ventricle. In the right ventricle the catheter was manipulated to enter a great vessel arising near the midline, which was interpreted as being the pulmonary artery, but it was not possible to get out into the lung fields. POSITION
OXYGEN
OXYGEN
SATURATION
CONTENT
BA* ......... 79.3 Great vessel ......... 87.5 BA* ......... 76.8 Great vessel ......... 86.1 RVoutflow ......... 86.4 RV inflow ......... 85.8 RA .... 65.8,65.6 SVC .... 64.8,65.8 PC ......... (98)
22.1 23.6
CAPACITY
PRESSURES (MM. HG)
27.0
110/75 110/60
mean mean
= 82 = 82
mean
= 10
105/8 23.0 17.7 (26.4)
BSA ......... 1.46 M2 O 2 Consumption (251 ml./min.) assumed Estimations (based on assumption great vessel is pulmonary artery): Systemic flow L/min ......... 5.7 Pulmonary flow L/min ......... 9.0 Effective pulmonary flow. . . . . . . . 2 . 9
3.9 L/min./M2
Left-to-right shunt L/min ...................... 3. 3 Right-to-Ieft shunt L/min ...................... 2.9 Systemic resistance ..................... 18 units Pulmonary resistance ..................... 12 units
* Simultaneous. The oxygen saturation data indicate a large left-to-right shunt at the ventricular level. There is a jump in oxygen content of about 5 volumes per cent from the right atrium to the right ventricle. Simultaneous sampling from the brachial artery and the pulmonary artery consistently showed a higher concentration of oxygen in the pulmonary artery than in the brachial artery. The mean pressures in the pulmonary artery and the brachial artery were essentially identical, but the diastolic level in the pulmonary artery was consistently lower. Based on the assumption that the great vessel entered is the pulmonary artery, the pulmonary vascular resistance is increased.
ROBERT A. MILLER, THOMAS G. BAFFES, ALBERT A. WILKINSON
This patient with her peripheral oxygen saturation approximately 80 per cent is not a candidate for current operations for transposition of the great vessels. Her disability is not due primarily to a transposed aorta getting venous blood from the right ventricle. She already has considerable intracardiac shunting, and her disability is, to a large degree, due to pulmonary vascular obstruction.
Thus far we have illustrated two types of cases in which we feel operation is indicated and one in which it probably is not. The fourth case is presented because a surgical decision is not easy to make. A transposition complex in which both great vessels arise from the right ventricle, the so-called double outlet right ventricle complex, is not rare. This anomaly occurs in 11 per cent of our postmortem cases. In these children the aorta is completely transposed, and there is a large ventricular septal defect. The pulmonary artery, however, arises entirely from the right ventricle, or is only slightly levoposed. CASE IV. This 2-year-old boy has been moderately cyanotic from birth. He has grown and developed moderately weH, but definitely tires more easily than other children his age. He breathes hard on exertion, and his cyanosis increases upon crying or when he is tired. At rest, however, he has only mild cyanosis of the lips and fingernails. Cardiac catheterization was carried out via the right saphenous vein, and the catheter was passed into the inferior and superior venae cavae, the right atrium and the right ventricle. On manipulation in the right ventricle the catheter could be passed into both the aorta and the pulmonary artery. In fact, the path of the catheter from the ventricle out the pulmonary artery seemed almost the same as in the normal heart. One could almost feel a crista, being assured of going into the pulmonary artery when the catheter tip was to the right of it or into the aorta when the catheter tip was to the left of it. After blood samples and pressures had been recorded a cine-angiocardiogram was done with the catheter in the right ventricle. Cardiac catheterization data are as foHows: POSITION
OXYGEN
OXYGEN
OXYGEN
PRESSURES
%SATU-
CONTENT
CAPACITY
(MM. HG)
RATION
SVC .... .47.5,51.5 RA .......... 54.2 RV outflow .......... 74.9 {AO .......... 69.7 Ao .......... 70.8 FA .......... 68.4 FA .......... 61.2 PA .......... 89.9 PA .......... 86.4 {FA .......... 71.1 PA .......... 90.4 RV .......... 77.1 RA ..... . .52.8 SVC .... ... 48.2 {PA ...... .. . 85.0 FA ...... ... 70.2 PC .......... (96.0) A-V
Systemic .... . ... 6.1 Pulmonary .......... 2 . 5
11.6 12.2 16.9 22.5 15.9 15.4
100/62 94/60
90/60 90/10 11.9 19.1 15.8 21. 6
Flow/M2 2.8 6.9
Resistance moderately elevated minimum about 6 units
mean = 70 mean = 70
1118
TRANSPOSITION OF THE GREAT VESSELS
The oxygen saturation data indicate that there is a large left-to-right shunt at the ventricular level. The oxygen saturation of blood samples obtained simultaneously from the pulmonary artery and femoral artery show that the pulmonary artery sample was repeatedly higher in oxygen saturation. The systolic blood pressure levels in the pulmonary artery, right ventricle, femoral artery and aorta were all within 5 mm. of each other. The cine-angiocardiogram shows both the aorta and pulmonary artery filling equally well and simultaneously from the right ventricle. The iStimated pulmonary resistance in this patient is moderately elevated, and the pulmonary flow is about two and one-half times the systemic flow. This child has a large heart and increased vascularity of the lung fields. Although his oxygen saturation is 70 per cent, he is definitely not as cyanotic as the usual patient with a transposition complex, and his growth and development has been fairly good. Although operation would improve him and would raise his peripheral oxygen saturation about 15 per cent, it would seem that his intracardiac pathology is such that it might be more prudent to delay operation, awaiting future surgical progress.
The foregoing may be summarized as follows: Present-day surgery for transposition of the great vessels is directed at sending more oxygenated blood out the aorta and directing the venous blood to the left side of the heart so that it will go out the pulmonary artery. Therefore the best candidates for surgery are the children who are most intensely cyanotic. For the child with a transposition complex who is not very cyanotic the risk of these operative procedures may not be warranted. The lack of intense cyanosis indicates that the child already has a considerable left-to-right shunt. The cause of a large left-to-right shunt is usually either pulmonary vascular obstruction or pulmonary stenosis. These children with a transposition of the great vessels, ventricular septal defect and mild pulmonary stenosis have been improved by present-day surgery. Those patients with a large left-toright shunt and evidence of high pulmonary vascular resistance have had a high mortality rate. Surgery is probably contraindicated for them at present. The most gratifying results from the Baffes type of procedure for transposition of the great vessels have been obtained in those children whose peripheral oxygen saturation has been between 35 and 70 per cent. SURGICAL CORRECTION OF TRANSPOSITION OF THE GREAT VESSELS
Transposition of the aorta and the pulmonary artery remains one of the greatest challenges to the cardiovascular surgeon. Surgical correction in the past included the addition of shunting devices between the pulmonary artery and the systemic circulation, attempts to convert the transposition to an operative tetralogy, attempts at transplanting the aorta and pulmonary artery back to the proper ventricle, and transplanting of the major veins of the heart, in order to compensate for the defect. The present operation at the Children's Memorial Hospital represents one of the latter types of operation.
ROBERT A. MILLER, THOMAS G. BAFFES, ALBERT A. WILKINSON
1119
The surgical patient is placed in the left lateral decubitus position, and the right hemithorax is opened. The lung is retracted downward. The right main pulmonary artery is isolated and temporarily ligated.in order to prevent pulmonary congestion. Prior to occluding the pulmonary artery the pressure is determined on the water manometer. If the pulmonary artery is small and collapsed and if the pressure in it is low, a subclavian pulmonary anastomosis is performed. If there is an adequate-sized pulmonary artery with the "feel" of adequate flow through it, the transplantation of the pulmonary veins and inferior vena cava is carried out. (1) A curved coarctation clamp is placed on the lateral aspect of the inferior vena cava in such a way that the flow of blood from the inferior vena cava into the right atrium is not occluded (Fig. 160, B, C). An incision is made in the excluded lip of the inferior vena cava, and a homologous aortic graft is anastomosed to the incision. (2) The right main stem bronchus is occluded with a temporary umbilical tape ligature, and the right pulmonary veins are divided from their point of entry into the left atrium. The distal end of the pulmonary veins is left open in order to avoid any hemorrhagic pulmonary congestion (Fig. 160, D, E). (3) The opposite end of the homologous aortic graft is then anastomosed to the left atrial stump of the pulmonary veins (Fig. 160, F). (4) A curved coarctation clamp is then applied to the lateral aspect of the right atrium, and the distal end of the pulmonary veins is anastomosed to the excluded wall of the right atrium (Fig. 160, F, G). (5) After completion of all the anastomoses the temporary occluding ligatures about the right main pulmonary artery and the right main stem bronchus are removed, and the patient is allowed a few minutes to become stable. (6) A no. 1 silk ligature is then placed about the inferior vena cava at its point of entry into the right atrium. This makes the flow of blood from the inferior vena cava through the homologous graft and into the left atrium obligatory. This method achieves transfer of approximately 60 per cent of the systemic venous return to the left atrium, from which it is eventually ejected into the pulmonary circuit, and 60 per cent of the pulmonary venous return into the right atrium, from which it eventually reaches the systemic circulation. Results
Sixy-seven patients have been operated upon by the technique described above, by various members of the surgical staff of The TABLE
23. Mortality Rate According to Age AGE GROUP
TOTAL CASES
SURVIVORS
DEATHS
MORTALITY RATE
71.4% 18.1 % 33.3% 38.8%
0-6 months. . . . . .. . .. 14 . 11 7 months-l year. . . . . . . Over 1 year ........... 42
28
10 2 14
Totals ........... 67
41
26
4 9
Children's Memorial Hospital. Twenty-six patients died at operation or in the immediate postoperative period, an operative mortality rate of 38.8 per cent. Forty patients survived the operation and were sent home, a survival rate of 60.6 per cent. Four of these patients died subsequently of pulmonary arteriosclerosis, intercurrent infection or other causes unrelated to the operative procedure (Table 23). In general, the surviving patients have shown satisfactory improvement in their cyanosis and increase in exercise tolerance. Preoperatively the patients had oxygen saturations ranging from 35 to 50 per
1120
TRANSPOSITION OF THE GREAT VESSELS
Tape around
t'iS/fIt: phreriC nerve I
I
/ - Intet'att'ial
RiQht
sulcus
pulmon.veina ____ Aortic S1\"dft suturedto IY.C.
Fig. 160. Steps in surgical correction of transposition of great vessels. (T. C. Baffes, W. A. Riker, A. DeBoer and W. J. Potts: Surgical Correction of Transposition of the Aorta and the Pulmonary Artery. J. Thoracic Surg., Vol. 34.)
cent of capacity. They had poor exercise tolerance, many of them being unable to walk or bear weight. Many were in frank congestive cardiac failure. Postoperatively the patient's color improved rather promptly, and by about two to three weeks postoperatively the oxygen saturation had risen to approximately 85 per cent. Within six to eight weeks after operation the patients showed increase in exercise tolerance, the muscle mass of the calves and thighs increased, and soon active ambulation was possible. The liver decreased in size, and the ascites disappeared. On x-ray examination of the chest a number of these patients showed a decrease in heart size. Many patients showed only a trace of cyanosis at rest. Analysis of Mortality Rates and Survivals
The youngest patient successfully operated on with this technique was six weeks old at the time of operation. The oldest was 12 years old. From an analysis of the mortality statistics based on age, the
ROBERT A. MILLER, THOMAS G. BAFFES, ALBERT A. WILKINSON
D
line of divisiOn of right pulm.
1121
Retractor
veins /
/
/
I
Right pu1m.veins
Fig. 160 (continued)
best time for this operation to be performed is some time after the age of six months, provided the patient does not deteriorate before he reaches that age. If deterioration occurs earlier, prompt operation should be done, since the condition usually is progressive and significantly alters mortality rate. Fourteen patients were operated upon at less than six months of age (Table 23). Ten died in the immediate postoperative period, a mortality rate of 71.4 per cent. Two of the four survivors, however, were in the newborn period, aged six weeks and seven weeks respectively. Eleven patients were operated upon at ages ranging from seven months to one year. Only two succumbed in the immediate postoperative period, a mortality rate of 18.1 per cent. The surviving patients in this age group gave some of the most striking clinical results. Forty-two patients were operated upon at ages over one year. Most of these were between three and five years of age. Fourteen patients died in the immediate postoperative period, an operative mortality
1122
TRANSPOSITION OF THE GREAT VESSELS
rate of 33.3 per cent. This age group offered a particular advantage in that they were large enough to permit introduction of a rnaximumsized homograft between the inferior vena cava and the left atrium, thereby eliminating the danger that subsequent growth of the child might render the size of the homograft inadequate for draining the lower part of the body. On the other hand, this danger has not materialized in the younger children who by now have been followed up over three years. Their azygos vein was left intact, and adequate collateral circulation has apparently kept pace with the patient's growth. Analysis of the causes of death is also illuminating. A number of these operative deaths were entirely technical and therefore can be prevented. As shown in Table 24, 14 patients died of acute congestive TABLE
24. Analysis of Causes of Operative and Delayed Mortality
Immediate operative deaths: Acute congestive failure. Cardiac arrest. Supraventricular tachycardia. Cerebrovascular accidents. Right pulmonary edema with anoxia. Hemorrhage from right lung, with congestion. Intercostal hemorrhage. Total.
... ... ... ... ... ... ... .
. . . . . . .
.. .. .. .. .. .. ..
.. 5 . .. ......... 4 .. 1 . 4 .. 5 .. . . .. 5 ........... 2 . ........... 26
Delayed deaths: Diarrhea ......... ' Pneumonitis. . . . . . . . . Pulmonary arteriosclerosis. . . . . . . . . Total. . . . . . . . .. . .. ....
1 1 2 4
failure, cardiac arrest during the procedure, or cerebral vascular accidents during or after operation. Generally, these events occurred in severely deteriorated patients and may be considered unavoidable. However, 10 operative deaths resulted from hemorrhagic congestion of the right lung or right pulmonary edema with anoxia. Most of these deaths occurred in the youngest age group and resulted either from insufficient control of the high pulmonary artery pressure during the operative procedure, or from attachment of the right pulmonary veins to the right atrium at too sharp an angle, resulting in partial obstruction of drainage of the right lung. More recently, with particular care in the handling and control of the right lung, these complications have been reduced. Four deaths occurred after the patients had been discharged from the hospital and were unrelated to the operative procedure. One patient died of pneumonitis. One patient died of severe Salmonella infection. Two others expired of episodes that were interpreted as pneumonitis, but at autopsy showed severe, far-advanced pulmonary arteriosclerosis.
ROBERT A. MILLER, THOMAS G. BAFFES, ALBERT A. WILKINSON
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SUMMARY
Although the operation described above has produced dramatic improvement in many of our patients with transposition of the great vessels, it is obviously not the final answer to this serious problem. The clinician does not advise operation merely because a procedure is now available. The patient is operated upon because he is severely handicapped and because his prognosis without operation is very poor. The high mortality rate of to-day's major cardiac procedures must be justified by proper selection of patients. Unless there is good reason to expect a great improvement in the patient's condition after operation, the risk may not be justified. Since the great majority of children with transposition of the great vessels die in the first year or two of life, an operation of this type, even though it only partially corrects the malformation, is a step in the right direction. 707 Fullerton Avenue Chicago 14, Illinois