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Cavopulmonary anastomosis for cyanotic congenital heart disease
Cavopulmonary anastomosis for cyanotic congenital heart disease G. A. Truster, M.D., D. MacGregor, M.D., and W. T. Mustard, M.D., Toronto, Ontario, Canada
Ihe most suitable palliative procedure for congenital cardiac defects producing cyano sis is still controversial. Waterston and Blalock shunts are preferred for tetralogy of Fallot. The procedure best suited to other types of cyanotic heart disease, such as tricuspid atresia, transposition of the great vessels with left ventricular outflow tract ob struction, or other cardiac anomalies with decreased pulmonary blood flow, is not clear.1 In patients with these cardiac defects, there is insufficient flow of venous blood from the systemic circulation to the pulmo nary artery. This can be improved by a cavopulmonary anastomosis, a circulatory bypass of the right heart by which blood is delivered from the superior vena cava di rectly into the right pulmonary artery.2 This operation was first described in 1951 by Carlon 3 as an experimental means of partial right heart bypass. Further studies by Glenn4 and Robicsek5 led to its clinical application, reported initially in the United States by Glenn0 and in Russia by Bakulev.7
by cavopulmonary anastomosis. However, as it is essentially irreversible, this method is most useful in cases in which a corrective procedure is difficult or impossible. The flow of venous blood depends upon venous pressure and the sucking effects of inspiration. With a shunt between the su perior vena cava and the distal divided end of the right pulmonary artery, more than one third of the total venous return will be oxygenated without passing through the heart.2 The main physiologic advantages of a cavopulmonary anastomosis over a sys temic artery-pulmonary artery shunt include the following: (1) No extra burden is placed on the systemic ventricle, (2) pure venous blood is directed to the right lung, and (3) pulmonary artery pressure is not significantly increased. A further advantage may be that flow through the cavopulmo nary shunt will vary with cardiac output to the upper part of the body, whereas flow through a systemic artery shunt will vary with arterial pressure.
Indication and advantages
Clinical material
Any malformation associated with re duced pulmonary blood flow may be helped
In 58 children, 17 days to 14 years of age, a cavopulmonary anastomosis was created at The Hospital for Sick Children, Toronto, in the period July, 1961, to July, 1970, for the following diseases: tricuspid atresia, 22 cases; transposition of the great vessels with ventricular septal defect and pulmonary stenosis, 22 cases; and a variety of complex malformations, 14 cases. Of the
From the Department of Surgery, The Hospital for Sick Children, and the University of Toronto, Toronto, Ontario, Canada. Received for publication March 26, 1971. Address for reprints: Dr. G. A. Trusler, The Hospital for Sick Children, 555 University Avenue, Toronto 101, Ontario, Canada.
803
The Journal of
8 0 4
Trusler,
MacGregor,
Mustard
Thoracic and Cardiovascular Surgery
NO OF CASES 11-
0-6 6-12 1
mos mos
3
4
5
6
7
8
9 10 11 12
AGE AT OPERATION
Fig. 1. Age at time of cavopulmonary anastomosis showing a high mortality rate in children younger than 6 months of age.
Fig. 2. Anastomosis between the side of the su perior vena cava and the end of the right pulmo nary artery. The superior vena cava is ligated immediately below the anastomosis.
transposition of the great vessels and pul monary stenosis with an intact ventricular septum. While the average age of patients under going cavopulmonary anastomosis was 4 years, 1 month, the majority were over 2 years of age (Fig. 1 ). Only 3 children were younger than 6 months old at operation, and 4 were between the ages of 6 and 12 months. The operations were performed under general surface hypothermia (30° to 33° C.) with an anterolateral approach through the third intercostal space. The distal end of the divided right pulmonary artery and the superior vena cava were joined by endto-side anastomosis (Fig. 2). The superior vena cava was ligated immediately below the anastomosis to produce an end-to-end effect and avoid a blind pocket in the su perior vena cava.
14, 7 had a single ventricle and pulmonary stenosis with or without transposition of the great vessels, 4 had a hypoplastic right ven tricle with either pulmonary atresia or tricuspid stenosis, 2 had a hypoplastic left ventricle with pulmonary stenosis and trans position of the great vessels, and 1 had
Results To assess the results of surgery we noted the degree of cyanosis, the exercise tol erance, the growth and development (based on weight and height percentiles), and the hemoglobin and hematocrit levels. The relationship of the results of surgery
Volume 62
Cyanotic congenital heart disease
Number 5
805
November, 1971
Table I. Results of cavopulmonary anastomosis in 58 children at The Hospital for Sick Children, Toronto, 1961 to 1970 No. of Diagnosis
children
Good
Fair
Tricuspid atresia TGV, VSD, PS Single ventricle, PS Other malformations
18 21 6 4
0 1 0 0
1 0 1 0
Total
49
1
2
|
Unchanged
Legend: TGV, Transposition of the great vessels. VSD, Ventricular septal defect.
to the original diagnosis are indicated in Table I. Cyanosis lessened markedly and exercise tolerance improved after operation in 18 of the 22 children with tricuspid atresia. Clinical signs of a significant in crease in superior vena caval pressure oc curred for a short time following operation in 4 of the 18 children. Two of these 4 had pleural effusion. The condition of 1 of the 22 children improved initially, but, due to an undiagnosed left superior vena cava, the cavopulmonary anastomosis thrombosed and a systemic artery—pulmonary artery shunt was necessary. Three children died. Two of them, aged 17 days and 4 months, respectively, died because the pulmonary ar tery was small and hence the anastomosis inadequate. The third child, who was ex tremely ill with intractable cardiac failure from a oversized Waterston shunt con structed 11 months previously, died due to sudden atelectasis of the contralateral lung. In the group of 22 children with trans position of the great vessels, ventricular sep tal defect, and pulmonary stenosis, color and exercise tolerance improved greatly after operation in 21 ; in 1 patient, improve ment was lessened when the innominate vein became thrombosed adjacent to the site of ligation of a left superior vena cava. No child in this group of 22 showed evidence of clinically significant elevation of superior vena caval pressure, but 2 children develop ed a right pleural effusion following opera tion. In 1 child, the effusion was associated with atelectasis, and in the other with pneumonia and cardiac failure. None died.
\
Died
Total
3 0 0 3
22 22 7 7 58
6 PS, Pulmonary
stenosis.
Of the 14 children who had a variety of less common cardiac malformations, 10 chil dren were classed as having good-to-excel lent results after operation, although 2 showed moderate elevation of superior vena caval pressure. In 1 child, the elevation of caval pressure was associated with a right pleural effusion which recurred repeatedly over several months. Angiography demon strated that the anastomosis was widely patent, and the elevation in caval pressure was considered to be a result of a tempo rary increase in pulmonary vascular resist ance, possibly secondary to parenchymal disease of the lung aggravated in turn by the pleural effusion. Once the pleural effusion stopped, the child did very well. Unexplainably, the condition of 1 other child was unimproved, and a systemic artery-pulmo nary artery shunt was necessary. Three pa tients died, 2 from thrombosis of the anas tomosis and 1 because the anastomosis was too small due to technical difficulties. Nine children in the series had function ing systemic artery-pulmonary artery shunts, three of which were Potts shunts, three right Blalock shunts (Fig. 3), and one a left Blalock shunt. In these 7 children, the original shunt was preserved to perfuse the left lung. The eighth child had both a Bla lock and a Potts shunt. The right Blalock was divided when the cavopulmonary anas tomosis was carried out. The condition of all 8 children was greatly improved by the cavopulmonary anastomosis. The ninth child, the patient with the large Waterston shunt in whom the shunt was narrowed
The Journal of
8 0 6
Truster,
MacGregor,
Mustard
Thoracic and Cardiovascular Surgery
NO OF CASES R.Sub
12-
Second Operation
11109876 543Fig. 3. Creation of a cavopulmonary anastomosis in the presence of a previous right Blalock anas tomosis. Flow through the Blalock anastomosis is preserved to perfuse the left lung.
and a cavopulmonary anastomosis was cre ated, died suddenly several days after op eration from atelectasis of the left lung. The long-term (up to 9 years) results have been good (Fig. 4). Generally, the improved exercise tolerance has been maintained. However, after several years, cyanosis has increased, and hemoglobin and hematocrit have risen in many children. Of the 49 children originally in greatly improved con dition after operation, only three have re quired a left systemic artery-pulmonary artery shunt because of increased cyanosis and diminished exercise tolerance. All 3 are children with tricuspid atresia, and the original cavopulmonary anastomoses had been constructed 4, 7, and 8 years earlier. Angiographie studies some years after anastomosis in 4 children, including the 3 above, indicate the following: (1) The anas tomosis has grown, (2) the superior vena cava drains freely into the right lung with out major collateral flow to the inferior vena cava, and (3) in 3 of the 4 there is selective flow to the lower part of the right lung with reduced flow to the upper lobe (Figs. 5 and 6).
21
1 2 3 4 5 6 7 8 9 FOLLOW UP-YEARS
Fig. 4. Length of follow-up of 52 children sur viving cavopulmonary anastomosis. Only 4 chil dren required further operation.
Discussion We find cavopulmonary anastomosis to be a safe and effective palliative procedure for treating certain cyanotic cardiac mal formations. The deaths, 6 of 58 children, have been chiefly caused by inadequate anastomosis because of a relatively small pulmonary artery or technical problems at operation. Unlike a high-pressure systemic artery-pulmonary artery shunt, the lowpressure cavopulmonary shunt is inadequate if the pulmonary artery is too small, making this operation frequently unsuitable for children under 6 months of age. Glenn8 states that, for a satisfactory result, the right pulmonary artery should be at least one half the diameter of the superior vena cava. The smallest right pulmonary artery we have used successfully to produce a func tioning cavopulmonary shunt was 6 mm. in external diameter. Edwards and Bargeron9 have delayed azygos vein ligation in infants with small pulmonary arteries. However, when the child is younger than 6 months of
Volume 62 Number 5
Cyanotic congenital heart disease 8 0 7
November, 1971
Fig. 6. Late angiographie study in another patient 8 years after operation reveals preferential flow to the lower part of the right lung with reduced flow to the upper lobe.
Fig. 5. Angiographie study 4 years after opera tion indicates widely patent cavopulmonary anas tomosis, little development of collateral circula tion, and balanced flow to whole right lung.
age or the pulmonary arteries are small, a systemic artery-pulmonary artery shunt is safer and preferable to cavopulmonary anas tomosis. Most of the deaths occurred early in our series, with no deaths for the past 3 years (22 operations). We encountered few complications when an adequate cavopulmonary anastomosis was created. Clinical signs of increased su perior vena caval pressure were noted temporarily in 6 of the 52 surviving chil dren. Four of these were children with tricuspid atresia. No increase in superior vena caval pressure occurred in children with the transposition of great vessels-ventricular septal defect-pulmonary stenosis complex, probably because the pulmonary arteries are larger in children with transposition than in children with tricuspid atresia. The child with a satisfactory cavopulmo nary anastomosis differs from the child with a systemic artery-pulmonary artery shunt. While the cavopulmonary anastomosis re-
duces cyanosis, the child is seldom truly pink. But it is our impression that his exer cise tolerance and growth are slightly better than those of a child with a systemic artery shunt; the heart is not hyperdynamic, and cardiac failure is rare. How long palliation achieved with a nonpulsatile cavopulmonary shunt lasts and how effective it will remain is unknown. Glenn10 has shown continued function and growth of the anastomosis with little or no increase in collateral flow to the inferior vena cava over a period of 10 years. Our experience is similar. Several years after a cavopulmo nary anastomosis, cyanosis deepens and hemoglobin and hematocrit increase in many children.11 We found this particularly true in children with tricuspid atresia, perhaps because they were among our earliest cases and have been followed longer. It is likely that flow to the left lung fails to increase as the child grows. Some of these children have been aided by the addition of a systemic artery-pulmonary artery shunt to the left lung, as reported by Boruchow and col leagues.12 Angiographie evidence of selective per fusion of the lower portions of the right lung by the cavopulmonary shunt, with re duced flow to the right upper lobe, is dis-
The Journal of
808
Trusler, MacGregor, Mustard
Thoracic and Cardiovascular Surgery
turbing. It may be caused by the combined effect of gravity and the nonpulsatile nature of the caval flow on the development of the pulmonary vascular bed. 12 · 13 How this will affect function of the right lung over many years is not clear. Several authors12· 141 ° report successful correction of tetralogy of Fallot in children with cavopulmonary shunts, leaving the shunt intact. While we have refrained from using this "irreversible" shunt for children with tetralogy of Fallot, we have used it successfully for 22 children with a potentially correctable lesion, transposition of the great vessels with ventricular septal defect and pulmonary stenosis; the youngest such pa tient was 11 months of age. This complex anomaly should be amenable to surgery. If the cavopulmonary shunt remains, the left ventricular outflow obstruction need only be enlarged enough to accommodate inferior vena caval return. However, we know of no successful correction. Our one attempt ended fatally, apparently from a postperfusion lung complication. Like Allen," we have been gratified by the degree of palliation achieved when a cavopulmonary shunt is added to a pre-exist ing Potts or Blalock shunt. By directing the arterial shunt to the left lung and the caval shunt to the right, it is possible to obtain good systemic oxygen saturation without excessive cardiac load. Some of these chil dren appear to live almost normal lives. With incorrectable defects, such as tricuspid atresia, perhaps this combination of shunts should be the goal of palliative therapy. If so, particularly in the younger child, the arterial anastomosis should be created first, preferably on the left side, and so con structed that it will grow slowly to a con trolled size which will be tolerated by the left lung when the right pulmonary artery is divided for the cavopulmonary anastomo sis. Flow through a cavopulmonary shunt is predictable when compared with flow through a systemic artery-pulmonary artery shunt, particularly if the latter grows. Con sequently, it is better to construct the sys temic arterial shunt first, so that both lungs
absorb the flow. The more predictable cavo pulmonary anastomosis can then be created when further palliation is needed, and the volume of blood flow through the arterial shunt is easily tolerated by the left lung alone. Summary From July, 1961, to June, 1970, cavo pulmonary anastomoses were created in 58 children with cyanotic congenital heart dis ease: tricuspid atresia (22 children), trans position of the great vessels with ventricular septal defect and pulmonary stenosis (22 children), a single ventricle with pulmo nary stenosis (7 children), and other mal formations (7 children). The anastomosis proved relatively safe and provided good palliation. Six patients died soon after operation, 5 mainly because a small right pulmonary artery rendered the anastomosis inadequate. Two of these 5 were less than 6 months of age. We believe that cavopulmonary anastomosis is unsuit able at this age. Of the 52 surviving children, 2 were in unimproved condition, 1 was moderately improved, and 49 were considered to have good to excellent results. Complications were few. Clinical signs of a significant increase in superior vena caval pressure were noted briefly in 6 of the surviving children, 2 of whom also had a temporary right pleural effusion. Long-term observation revealed that many children develop deepening cyanosis several years after the cavopulmonary anastomosis. Their exercise tolerance remains improved, but hemoglobin and hematocrit levels in crease. Further shunt procedures on the left side have been necessary in only 3 chil dren thus far. This combination of cavo pulmonary shunt on the right and arterial shunt on the left has proved very effective. Previous systemic artery-pulmonary artery shunts were preserved at the time of the cavopulmonary anastomosis in 9 children. Eight of these were much improved by the additional procedure. Late angiographie studies show the cavo-
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Cyanotic congenital heart disease 8 0 9
Number 5 November, 1971
pulmonary anastomosis has grown and the blood flow from the superior vena cava to the right lung has been maintained. In 3 of 4 children there was selective flow to the lower part of the right lung with diminished flow to the right upper lobe. REFERENCES 1 Reed, W. A., Kittle, C. F., and Heilbrunn, A . : Superior Vena Cava-Pulmonary Artery Anas tomosis: Palliation of Cyanotic Congenital Heart Disease, Arch. Surg. 86: 87, 1963. 2 Glenn, W. W. L., Brown, M., and Whittemore, R.: Circulating Bypass of the Right Side of the Heart: Cavopulmonary Artery Shunt— Indications and Results (Reports of a Col lected Series of 537 Cases), in Cassels, D . E., editor: The Heart and Circulation in the New born and Infant, New York, 1966, Grune & Stratton, Inc., p. 345. 3 Carlon, C. A., Mondini, P. G., and de Marchi, R.: Surgical Treatment of Some Cardiovas cular Diseases (New Vascular Anastomosis), J. Int. Coll. Surg. 16: 1, 1951. 4 Glenn, W. W. L., and Patino, J. F . : Circula tory Bypass of Right Heart: Preliminary Ob servations on Direct Delivery of Vena Caval Blood Into Pulmonary Arterial Circulation. Azygos Vein-Pulmonary Shunt, Yale J. Biol. Med. 27: 147, 1954. 5 Robicsek, F., Magistro, R., Foti, E., Robicsek, L., and Sänger, P. W.: Vena Cava-Pulmonary Artery Anastomosis for Vascularization of the Lung, J. THORAC.
SURG. 35: 440, 1958.
6 Glenn, W. W. L.: Circulatory Bypass of the Right Side of the Heart. IV. Shunt Between Superior Vena Cava and Distal Right Pulmo nary Artery—Report of Clinical Application, N. Engl. J. Med. 259: 117, 1958. 7 Bakulev, A. N., and Kolesnikov, S. A.: Anas tomosis of Superior Vena Cava and Pulmo nary Artery in the Surgical Treatment of Certain Congenital Defects of the Heart, J. THORAC. SURG. 37: 693, 1959.
8 Glenn, W. W. L., Ordway, N . K., Talner, N . S., and Call, E. P., Jr.: Circulatory Bypass of the Right Side of the Heart. VI. Shunt Be tween Superior Vena Cava and Distal Right
Pulmonary Artery: Report of Clinical Applica tion in Thirty-eight Cases, Circulation 3 1 : 172, 1965. 9 Edwards, W. S., and Bargeron, L. M., J r . : The Importance of the Azygos Vein in Su perior Vena Cava-Pulmonary Artery Anas tomosis,
J.
THORAC.
CARDIOVASC.
SURG.
46:
811, 1963. 10 Glenn, W. W. L., Spencer, R. P., Deren, M . M., and Hidetsugu, T.: Functional Changes in Pulmonary Circulation Following Cava-Pul monary Artery Shunt, Circulation 42: 157, 1970 (Suppl. 3). 11 Bopp, R. K., Larsen, P. B., Caddell, Joan L., Patrick, J. R., Hipona, F . A., and Glenn, W . W. L. : Surgical Considerations for Treatment of Congenital Tricuspid Atresia and Stenosis: With Particular Reference to Vena Cava-Pul monary Artery Anastomosis, J. THORAC. CAR DIOVASC SURG. 4 3 : 97, 1962.
12 Boruchow, I. B., Swenson, E. W., Elliott, L. P., Bartley, T . D . , Wheat, M . W., Jr., and Schiebler, G. L.: Study of the Mechanisms of Shunt Failure after Superior Vena Cava-Right Pulmonary Artery Anastomosis, J. THORAC CARDIOVASC
SURG. 60: 5 3 1 , 1970.
13 Samanek, M., Oppelt, A., Kasalicky, J., and Voriskova, M.: Distribution of Pulmonary Blood Flow After Cavopulmonary Anastomo sis (Glenn Operation), Br. Heart J. 3 1 : 511, 1969. 14 Claxton, C. P., Jr., and Sabiston, D. C , J r . : Correction of Tetralogy of Fallot Following Superior Vena Cava to Pulmonary Artery Shunt, J. T H O R A C CARDIOVASC. SURG. 57: 475,
1969. 15 Sachs, B. F., Pontius, R. G., and Zuberbuhler, J. R.: T h e Clinical Use of the Superior Vena Cava-Pulmonary Artery Shunt: A Report of 20 Cases, J. Pediat. Surg. 3: 364, 1968. 16 Martin, S. P., Anabtawi, I. N . , Selmonsky, C. A., Folger, G. M., Ellison, L. T., and Ellison, R. G.: Long-Term Follow-up After Superior Vena Cava-Right Pulmonary Artery Anasto mosis, Ann. Thorac. Surg. 9: 339, 1970. 17 Allen, R. G.: T h e Addition of Cava Pulmo nary Artery Shunts to Patients With Existing Systemic Pulmonary Artery Shunts, J. Pediatr. Surg. 5: 102, 1970.
Ihe most suitable palliative procedure for congenital cardiac defects producing cyano sis is still controversial. Waterston and Blalock shunts are preferred for tetralogy of Fallot. The procedure best suited to other types of cyanotic heart disease, such as tricuspid atresia, transposition of the great vessels with left ventricular outflow tract ob struction, or other cardiac anomalies with decreased pulmonary blood flow, is not clear.1 In patients with these cardiac defects, there is insufficient flow of venous blood from the systemic circulation to the pulmo nary artery. This can be improved by a cavopulmonary anastomosis, a circulatory bypass of the right heart by which blood is delivered from the superior vena cava di rectly into the right pulmonary artery.2 This operation was first described in 1951 by Carlon 3 as an experimental means of partial right heart bypass. Further studies by Glenn4 and Robicsek5 led to its clinical application, reported initially in the United States by Glenn0 and in Russia by Bakulev.7
by cavopulmonary anastomosis. However, as it is essentially irreversible, this method is most useful in cases in which a corrective procedure is difficult or impossible. The flow of venous blood depends upon venous pressure and the sucking effects of inspiration. With a shunt between the su perior vena cava and the distal divided end of the right pulmonary artery, more than one third of the total venous return will be oxygenated without passing through the heart.2 The main physiologic advantages of a cavopulmonary anastomosis over a sys temic artery-pulmonary artery shunt include the following: (1) No extra burden is placed on the systemic ventricle, (2) pure venous blood is directed to the right lung, and (3) pulmonary artery pressure is not significantly increased. A further advantage may be that flow through the cavopulmo nary shunt will vary with cardiac output to the upper part of the body, whereas flow through a systemic artery shunt will vary with arterial pressure.
Indication and advantages
Clinical material
Any malformation associated with re duced pulmonary blood flow may be helped
In 58 children, 17 days to 14 years of age, a cavopulmonary anastomosis was created at The Hospital for Sick Children, Toronto, in the period July, 1961, to July, 1970, for the following diseases: tricuspid atresia, 22 cases; transposition of the great vessels with ventricular septal defect and pulmonary stenosis, 22 cases; and a variety of complex malformations, 14 cases. Of the
From the Department of Surgery, The Hospital for Sick Children, and the University of Toronto, Toronto, Ontario, Canada. Received for publication March 26, 1971. Address for reprints: Dr. G. A. Trusler, The Hospital for Sick Children, 555 University Avenue, Toronto 101, Ontario, Canada.
803
The Journal of
8 0 4
Trusler,
MacGregor,
Mustard
Thoracic and Cardiovascular Surgery
NO OF CASES 11-
0-6 6-12 1
mos mos
3
4
5
6
7
8
9 10 11 12
AGE AT OPERATION
Fig. 1. Age at time of cavopulmonary anastomosis showing a high mortality rate in children younger than 6 months of age.
Fig. 2. Anastomosis between the side of the su perior vena cava and the end of the right pulmo nary artery. The superior vena cava is ligated immediately below the anastomosis.
transposition of the great vessels and pul monary stenosis with an intact ventricular septum. While the average age of patients under going cavopulmonary anastomosis was 4 years, 1 month, the majority were over 2 years of age (Fig. 1 ). Only 3 children were younger than 6 months old at operation, and 4 were between the ages of 6 and 12 months. The operations were performed under general surface hypothermia (30° to 33° C.) with an anterolateral approach through the third intercostal space. The distal end of the divided right pulmonary artery and the superior vena cava were joined by endto-side anastomosis (Fig. 2). The superior vena cava was ligated immediately below the anastomosis to produce an end-to-end effect and avoid a blind pocket in the su perior vena cava.
14, 7 had a single ventricle and pulmonary stenosis with or without transposition of the great vessels, 4 had a hypoplastic right ven tricle with either pulmonary atresia or tricuspid stenosis, 2 had a hypoplastic left ventricle with pulmonary stenosis and trans position of the great vessels, and 1 had
Results To assess the results of surgery we noted the degree of cyanosis, the exercise tol erance, the growth and development (based on weight and height percentiles), and the hemoglobin and hematocrit levels. The relationship of the results of surgery
Volume 62
Cyanotic congenital heart disease
Number 5
805
November, 1971
Table I. Results of cavopulmonary anastomosis in 58 children at The Hospital for Sick Children, Toronto, 1961 to 1970 No. of Diagnosis
children
Good
Fair
Tricuspid atresia TGV, VSD, PS Single ventricle, PS Other malformations
18 21 6 4
0 1 0 0
1 0 1 0
Total
49
1
2
|
Unchanged
Legend: TGV, Transposition of the great vessels. VSD, Ventricular septal defect.
to the original diagnosis are indicated in Table I. Cyanosis lessened markedly and exercise tolerance improved after operation in 18 of the 22 children with tricuspid atresia. Clinical signs of a significant in crease in superior vena caval pressure oc curred for a short time following operation in 4 of the 18 children. Two of these 4 had pleural effusion. The condition of 1 of the 22 children improved initially, but, due to an undiagnosed left superior vena cava, the cavopulmonary anastomosis thrombosed and a systemic artery—pulmonary artery shunt was necessary. Three children died. Two of them, aged 17 days and 4 months, respectively, died because the pulmonary ar tery was small and hence the anastomosis inadequate. The third child, who was ex tremely ill with intractable cardiac failure from a oversized Waterston shunt con structed 11 months previously, died due to sudden atelectasis of the contralateral lung. In the group of 22 children with trans position of the great vessels, ventricular sep tal defect, and pulmonary stenosis, color and exercise tolerance improved greatly after operation in 21 ; in 1 patient, improve ment was lessened when the innominate vein became thrombosed adjacent to the site of ligation of a left superior vena cava. No child in this group of 22 showed evidence of clinically significant elevation of superior vena caval pressure, but 2 children develop ed a right pleural effusion following opera tion. In 1 child, the effusion was associated with atelectasis, and in the other with pneumonia and cardiac failure. None died.
\
Died
Total
3 0 0 3
22 22 7 7 58
6 PS, Pulmonary
stenosis.
Of the 14 children who had a variety of less common cardiac malformations, 10 chil dren were classed as having good-to-excel lent results after operation, although 2 showed moderate elevation of superior vena caval pressure. In 1 child, the elevation of caval pressure was associated with a right pleural effusion which recurred repeatedly over several months. Angiography demon strated that the anastomosis was widely patent, and the elevation in caval pressure was considered to be a result of a tempo rary increase in pulmonary vascular resist ance, possibly secondary to parenchymal disease of the lung aggravated in turn by the pleural effusion. Once the pleural effusion stopped, the child did very well. Unexplainably, the condition of 1 other child was unimproved, and a systemic artery-pulmo nary artery shunt was necessary. Three pa tients died, 2 from thrombosis of the anas tomosis and 1 because the anastomosis was too small due to technical difficulties. Nine children in the series had function ing systemic artery-pulmonary artery shunts, three of which were Potts shunts, three right Blalock shunts (Fig. 3), and one a left Blalock shunt. In these 7 children, the original shunt was preserved to perfuse the left lung. The eighth child had both a Bla lock and a Potts shunt. The right Blalock was divided when the cavopulmonary anas tomosis was carried out. The condition of all 8 children was greatly improved by the cavopulmonary anastomosis. The ninth child, the patient with the large Waterston shunt in whom the shunt was narrowed
The Journal of
8 0 6
Truster,
MacGregor,
Mustard
Thoracic and Cardiovascular Surgery
NO OF CASES R.Sub
12-
Second Operation
11109876 543Fig. 3. Creation of a cavopulmonary anastomosis in the presence of a previous right Blalock anas tomosis. Flow through the Blalock anastomosis is preserved to perfuse the left lung.
and a cavopulmonary anastomosis was cre ated, died suddenly several days after op eration from atelectasis of the left lung. The long-term (up to 9 years) results have been good (Fig. 4). Generally, the improved exercise tolerance has been maintained. However, after several years, cyanosis has increased, and hemoglobin and hematocrit have risen in many children. Of the 49 children originally in greatly improved con dition after operation, only three have re quired a left systemic artery-pulmonary artery shunt because of increased cyanosis and diminished exercise tolerance. All 3 are children with tricuspid atresia, and the original cavopulmonary anastomoses had been constructed 4, 7, and 8 years earlier. Angiographie studies some years after anastomosis in 4 children, including the 3 above, indicate the following: (1) The anas tomosis has grown, (2) the superior vena cava drains freely into the right lung with out major collateral flow to the inferior vena cava, and (3) in 3 of the 4 there is selective flow to the lower part of the right lung with reduced flow to the upper lobe (Figs. 5 and 6).
21
1 2 3 4 5 6 7 8 9 FOLLOW UP-YEARS
Fig. 4. Length of follow-up of 52 children sur viving cavopulmonary anastomosis. Only 4 chil dren required further operation.
Discussion We find cavopulmonary anastomosis to be a safe and effective palliative procedure for treating certain cyanotic cardiac mal formations. The deaths, 6 of 58 children, have been chiefly caused by inadequate anastomosis because of a relatively small pulmonary artery or technical problems at operation. Unlike a high-pressure systemic artery-pulmonary artery shunt, the lowpressure cavopulmonary shunt is inadequate if the pulmonary artery is too small, making this operation frequently unsuitable for children under 6 months of age. Glenn8 states that, for a satisfactory result, the right pulmonary artery should be at least one half the diameter of the superior vena cava. The smallest right pulmonary artery we have used successfully to produce a func tioning cavopulmonary shunt was 6 mm. in external diameter. Edwards and Bargeron9 have delayed azygos vein ligation in infants with small pulmonary arteries. However, when the child is younger than 6 months of
Volume 62 Number 5
Cyanotic congenital heart disease 8 0 7
November, 1971
Fig. 6. Late angiographie study in another patient 8 years after operation reveals preferential flow to the lower part of the right lung with reduced flow to the upper lobe.
Fig. 5. Angiographie study 4 years after opera tion indicates widely patent cavopulmonary anas tomosis, little development of collateral circula tion, and balanced flow to whole right lung.
age or the pulmonary arteries are small, a systemic artery-pulmonary artery shunt is safer and preferable to cavopulmonary anas tomosis. Most of the deaths occurred early in our series, with no deaths for the past 3 years (22 operations). We encountered few complications when an adequate cavopulmonary anastomosis was created. Clinical signs of increased su perior vena caval pressure were noted temporarily in 6 of the 52 surviving chil dren. Four of these were children with tricuspid atresia. No increase in superior vena caval pressure occurred in children with the transposition of great vessels-ventricular septal defect-pulmonary stenosis complex, probably because the pulmonary arteries are larger in children with transposition than in children with tricuspid atresia. The child with a satisfactory cavopulmo nary anastomosis differs from the child with a systemic artery-pulmonary artery shunt. While the cavopulmonary anastomosis re-
duces cyanosis, the child is seldom truly pink. But it is our impression that his exer cise tolerance and growth are slightly better than those of a child with a systemic artery shunt; the heart is not hyperdynamic, and cardiac failure is rare. How long palliation achieved with a nonpulsatile cavopulmonary shunt lasts and how effective it will remain is unknown. Glenn10 has shown continued function and growth of the anastomosis with little or no increase in collateral flow to the inferior vena cava over a period of 10 years. Our experience is similar. Several years after a cavopulmo nary anastomosis, cyanosis deepens and hemoglobin and hematocrit increase in many children.11 We found this particularly true in children with tricuspid atresia, perhaps because they were among our earliest cases and have been followed longer. It is likely that flow to the left lung fails to increase as the child grows. Some of these children have been aided by the addition of a systemic artery-pulmonary artery shunt to the left lung, as reported by Boruchow and col leagues.12 Angiographie evidence of selective per fusion of the lower portions of the right lung by the cavopulmonary shunt, with re duced flow to the right upper lobe, is dis-
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Thoracic and Cardiovascular Surgery
turbing. It may be caused by the combined effect of gravity and the nonpulsatile nature of the caval flow on the development of the pulmonary vascular bed. 12 · 13 How this will affect function of the right lung over many years is not clear. Several authors12· 141 ° report successful correction of tetralogy of Fallot in children with cavopulmonary shunts, leaving the shunt intact. While we have refrained from using this "irreversible" shunt for children with tetralogy of Fallot, we have used it successfully for 22 children with a potentially correctable lesion, transposition of the great vessels with ventricular septal defect and pulmonary stenosis; the youngest such pa tient was 11 months of age. This complex anomaly should be amenable to surgery. If the cavopulmonary shunt remains, the left ventricular outflow obstruction need only be enlarged enough to accommodate inferior vena caval return. However, we know of no successful correction. Our one attempt ended fatally, apparently from a postperfusion lung complication. Like Allen," we have been gratified by the degree of palliation achieved when a cavopulmonary shunt is added to a pre-exist ing Potts or Blalock shunt. By directing the arterial shunt to the left lung and the caval shunt to the right, it is possible to obtain good systemic oxygen saturation without excessive cardiac load. Some of these chil dren appear to live almost normal lives. With incorrectable defects, such as tricuspid atresia, perhaps this combination of shunts should be the goal of palliative therapy. If so, particularly in the younger child, the arterial anastomosis should be created first, preferably on the left side, and so con structed that it will grow slowly to a con trolled size which will be tolerated by the left lung when the right pulmonary artery is divided for the cavopulmonary anastomo sis. Flow through a cavopulmonary shunt is predictable when compared with flow through a systemic artery-pulmonary artery shunt, particularly if the latter grows. Con sequently, it is better to construct the sys temic arterial shunt first, so that both lungs
absorb the flow. The more predictable cavo pulmonary anastomosis can then be created when further palliation is needed, and the volume of blood flow through the arterial shunt is easily tolerated by the left lung alone. Summary From July, 1961, to June, 1970, cavo pulmonary anastomoses were created in 58 children with cyanotic congenital heart dis ease: tricuspid atresia (22 children), trans position of the great vessels with ventricular septal defect and pulmonary stenosis (22 children), a single ventricle with pulmo nary stenosis (7 children), and other mal formations (7 children). The anastomosis proved relatively safe and provided good palliation. Six patients died soon after operation, 5 mainly because a small right pulmonary artery rendered the anastomosis inadequate. Two of these 5 were less than 6 months of age. We believe that cavopulmonary anastomosis is unsuit able at this age. Of the 52 surviving children, 2 were in unimproved condition, 1 was moderately improved, and 49 were considered to have good to excellent results. Complications were few. Clinical signs of a significant increase in superior vena caval pressure were noted briefly in 6 of the surviving children, 2 of whom also had a temporary right pleural effusion. Long-term observation revealed that many children develop deepening cyanosis several years after the cavopulmonary anastomosis. Their exercise tolerance remains improved, but hemoglobin and hematocrit levels in crease. Further shunt procedures on the left side have been necessary in only 3 chil dren thus far. This combination of cavo pulmonary shunt on the right and arterial shunt on the left has proved very effective. Previous systemic artery-pulmonary artery shunts were preserved at the time of the cavopulmonary anastomosis in 9 children. Eight of these were much improved by the additional procedure. Late angiographie studies show the cavo-
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Cyanotic congenital heart disease 8 0 9
Number 5 November, 1971
pulmonary anastomosis has grown and the blood flow from the superior vena cava to the right lung has been maintained. In 3 of 4 children there was selective flow to the lower part of the right lung with diminished flow to the right upper lobe. REFERENCES 1 Reed, W. A., Kittle, C. F., and Heilbrunn, A . : Superior Vena Cava-Pulmonary Artery Anas tomosis: Palliation of Cyanotic Congenital Heart Disease, Arch. Surg. 86: 87, 1963. 2 Glenn, W. W. L., Brown, M., and Whittemore, R.: Circulating Bypass of the Right Side of the Heart: Cavopulmonary Artery Shunt— Indications and Results (Reports of a Col lected Series of 537 Cases), in Cassels, D . E., editor: The Heart and Circulation in the New born and Infant, New York, 1966, Grune & Stratton, Inc., p. 345. 3 Carlon, C. A., Mondini, P. G., and de Marchi, R.: Surgical Treatment of Some Cardiovas cular Diseases (New Vascular Anastomosis), J. Int. Coll. Surg. 16: 1, 1951. 4 Glenn, W. W. L., and Patino, J. F . : Circula tory Bypass of Right Heart: Preliminary Ob servations on Direct Delivery of Vena Caval Blood Into Pulmonary Arterial Circulation. Azygos Vein-Pulmonary Shunt, Yale J. Biol. Med. 27: 147, 1954. 5 Robicsek, F., Magistro, R., Foti, E., Robicsek, L., and Sänger, P. W.: Vena Cava-Pulmonary Artery Anastomosis for Vascularization of the Lung, J. THORAC.
SURG. 35: 440, 1958.
6 Glenn, W. W. L.: Circulatory Bypass of the Right Side of the Heart. IV. Shunt Between Superior Vena Cava and Distal Right Pulmo nary Artery—Report of Clinical Application, N. Engl. J. Med. 259: 117, 1958. 7 Bakulev, A. N., and Kolesnikov, S. A.: Anas tomosis of Superior Vena Cava and Pulmo nary Artery in the Surgical Treatment of Certain Congenital Defects of the Heart, J. THORAC. SURG. 37: 693, 1959.
8 Glenn, W. W. L., Ordway, N . K., Talner, N . S., and Call, E. P., Jr.: Circulatory Bypass of the Right Side of the Heart. VI. Shunt Be tween Superior Vena Cava and Distal Right
Pulmonary Artery: Report of Clinical Applica tion in Thirty-eight Cases, Circulation 3 1 : 172, 1965. 9 Edwards, W. S., and Bargeron, L. M., J r . : The Importance of the Azygos Vein in Su perior Vena Cava-Pulmonary Artery Anas tomosis,
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811, 1963. 10 Glenn, W. W. L., Spencer, R. P., Deren, M . M., and Hidetsugu, T.: Functional Changes in Pulmonary Circulation Following Cava-Pul monary Artery Shunt, Circulation 42: 157, 1970 (Suppl. 3). 11 Bopp, R. K., Larsen, P. B., Caddell, Joan L., Patrick, J. R., Hipona, F . A., and Glenn, W . W. L. : Surgical Considerations for Treatment of Congenital Tricuspid Atresia and Stenosis: With Particular Reference to Vena Cava-Pul monary Artery Anastomosis, J. THORAC. CAR DIOVASC SURG. 4 3 : 97, 1962.
12 Boruchow, I. B., Swenson, E. W., Elliott, L. P., Bartley, T . D . , Wheat, M . W., Jr., and Schiebler, G. L.: Study of the Mechanisms of Shunt Failure after Superior Vena Cava-Right Pulmonary Artery Anastomosis, J. THORAC CARDIOVASC
SURG. 60: 5 3 1 , 1970.
13 Samanek, M., Oppelt, A., Kasalicky, J., and Voriskova, M.: Distribution of Pulmonary Blood Flow After Cavopulmonary Anastomo sis (Glenn Operation), Br. Heart J. 3 1 : 511, 1969. 14 Claxton, C. P., Jr., and Sabiston, D. C , J r . : Correction of Tetralogy of Fallot Following Superior Vena Cava to Pulmonary Artery Shunt, J. T H O R A C CARDIOVASC. SURG. 57: 475,
1969. 15 Sachs, B. F., Pontius, R. G., and Zuberbuhler, J. R.: T h e Clinical Use of the Superior Vena Cava-Pulmonary Artery Shunt: A Report of 20 Cases, J. Pediat. Surg. 3: 364, 1968. 16 Martin, S. P., Anabtawi, I. N . , Selmonsky, C. A., Folger, G. M., Ellison, L. T., and Ellison, R. G.: Long-Term Follow-up After Superior Vena Cava-Right Pulmonary Artery Anasto mosis, Ann. Thorac. Surg. 9: 339, 1970. 17 Allen, R. G.: T h e Addition of Cava Pulmo nary Artery Shunts to Patients With Existing Systemic Pulmonary Artery Shunts, J. Pediatr. Surg. 5: 102, 1970.