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Results of Superior Vena Cava-to-Pulmonary Artery Shunt in the Treatment of Cyanotic Heart Disease
Results of Superior Vena Cava-toPulmonary Artery Shunt in the Treatment of Cvanotic Heart Disease Prinya Sakiyalak, M.D., Jay L. Ankeney, M.D., Jerome Liebman, M.D., a n d James DeMeules, M.D. ABSTRACT Since 1961, superior vena cava-to-pulmonary artery (SVC-PA) shunts have been performed in 31 patients with cyanotic heart disease. Of the 11 operative deaths, 8 were due to superior vena caval syndrome and 3 to pulmonary insufficiency. Superior vena caval syndrome was prevented in 8 consecutive patients by adjusting the degree of venous obstruction to keep superior vena caval pressure below 30 cm. H20. There were 3 late deaths among 17 patients who were followed for from one to nine years. All survivors experienced initial palliation, but only 4 of 13 patients followed for more than three years continued to do well. The other 9 patients developed more polycythemia and cyanosis, and 5 required reoperation with ligation of the left superior vena cava and collateral venous channels, together with creation of a systemic pulmonary artery shunt in 4. Late failure of the SVC-PA shunt appears to be the result of “venous steal” through the left superior vena cava and collateral venous channels together with progression of pulmonary stenosis.
S
uperior vena cava-to-pulmonary artery shunt for the palliative treatment of congenital cyanotic heart disease with decreased pulmonary circulation was introduced independently by Glenn [8], Robicsek [lo], and Bakulev [Z] and their colleagues. This method for increasing pulmonary blood flow using venous blood results in excellent initial palliation [4,7, 111. However, the type of cyanotic heart disease best treated by this method remains unclear, and relatively few long-term results have been reported [l, 3, 91. Therefore, we reviewed our experience with 31 patients in whom an SVC-PA shunt operation was performed during the past ten years, and the results of this study are herein reported.
Clinical Materials and Methods A superior vena cava-to-pulmonary artery shunt operation was performed in 31 patients with cyanotic heart lesions as listed in the Table. From the Departments of Thoracic Surgery and Pediatric Cardiology, University Hospitals of Cleveland, Cleveland, Ohio. Presented at the Seventh Annual Meeting of The Society of Thoracic Surgeons, Dallas, Tex., Jan. 18-20, 1971. Address reprint requests to Dr. Ankeney, University Hospitals of Cleveland, 2065 Adelbert Rd., Cleveland, Ohio 44106.
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Results of SVC-PA Shunt RESULTS IN 31 PATIENTS UNDERGOING S V C P A SHUNT OPERATION
Patient Sex & Age
Date of Operation
W.S.
M, 10yr.
5/16/61
M.B.
M, 3wk.
12/15/61
P. S.
M, 1Gyr.
1/25/62
A.D.
F, 3yr.
4/25/62
R.S.
M, 3?4yr.
6/20/62
N.V.
M, 3?4mo.
7/11/62
S.S.
M, l%yr.
11/8/62
B. J.
F, 1 yr.
4/1/63
B.B.
F, 7mo.
6/6/63
D.F.
M, 2mo.
7/22/63
A.D.
M, 2mo.
1/14/64
J.C.
M, 4?4mo.
214164
R.G.
M, 10yr.
6/9/64
B. S.
F, 5mo.
71 13/64
W . M . M, 4?hmo.
11/4/64
D.T.
F, 2mo.
11/20/64
R.W.
M, 2days
12/19/64
R.L.
M, 4days
12/29/64
Diagnosis T G V with pulmonary stenosis Pulmonary atresia with VSD Dextrocardia with pulmonary atresia PC common A-V valve Tricuspid atresia Dextrocardia with VSD, pulmonary atresia, & hypoplastic RV T G V with pulmonary stenosis Tricuspid atresia
Dextrocardia with pulmonary atresia & VSD, PDA Tricuspid atresia Pulmonary atresia & VSD T G V with pulmonary stenosis Pulmonary atresia & VSD Pulmonary atresia & VSD T G V & pulmonary stenosis Hypoplastic RV with pulmonary atresia & intact ventricular septum T G V & pulmonary stenosis T G V & pulmonary stenosis Hypoplastic RV with pulmonary atresia & intact ventricular septum
Result Good
Good after ligation of left SVC & left Blalock 6 mo. later Death-respiratory insufficiency Death-SVC syndrome Late death 1 mo. postop. Death-SVC syndrome Good after complete ligation of SVC & left Blalock 6 yr. later Good after ligation of left SVC 7 yr. later Death-SVC drome Death-SVC drome Good except Hct. Death-SVC drome Good
synsynrising syn-
Late death 8 mo. postop. Dea th-respiratory insufficiency Good except rising Hct. Death-SVC syndrome Death-SVC syndrome
SAKIYALAK E T AL. TABLE (Continued)
Patient Sex &Age
Date of Operation
T.W.
M, 8mo.
4/ 16f 65
M. E.
F, 6mo.
9/7/65
J.A.
F, 2mo.
R. E.
M, l%yr.
G.G.
F, 5days
D.O.
F, 2%mo.
TGV & pulmonary stenosis 11/18/65 TGV with intact ventricular septum & hypoplastic LV 1017166 Pulmonary atresia & VSD 12/6/66 Double-outlet RV with pulmonary atresia 4/21/67 Tricuspid atresia
D. E. K. J. M.W.
F, 4mo. M, 8mo. F, lmo.
7/13/67 9/7/67 2/5/68
H. S.
M, 6yr.
7/9/68
L. B.
F, 6mo.
R.H.
M, 3mo.
K.B.
M, 2days
Diagnosis TGV k pulmonary stenosis
Tricuspid atresia Tricuspid atresia Pulmonary atresia & VSD
TGV with pulmonary stenosis 2/27/69 TGV with pulmonary stenosis 1/15/70 TGV with pulmonary stenosis 4/4/70 Hypoplastic RV with pulmonary atresia & intact ventricular septum
Result Good after ligation of left SVC & aorta-toleft PA shunt 5% yr. later Good except rising Hct. Late death 16 mo. postop. Good except rising Hct. Death-SVC syndrome Good after left SVCPA shunt 3 wk. later Good Good Good after ligation left SVC 2 mo. later & left Blalock 2% yr. later Good Good except rising Hct. Good Death-respira tory insufficiency
T G V = transposition of great vessels; VSD = ventricular septal defect; RV = right ventricle; PDA = patent ductus arteriosus; Hct. = hematocrit; LV = left ventricle.
Twelve patients had transposition of the great vessels with pulmonary stenosis, 6 had tricuspid atresia, 6 had pulmonary atresia with ventricular septal defect, 3 had pulmonary atresia with hypoplastic right ventricle and intact ventricular septum, 3 had dextrocardia with complicated intracardiac anomalies, and 1 had double-outlet right ventricle with pulmonary atresia. There were 18 male and 13 female patients. T h e ages ranged from 2 days to 10 years with 19 of the patients 6 months of age or less. I n 25 patients the distal end of the divided right pulmonary artery was sutured to the side of the superior vena cava, which was completely or partially ligated at its junction with the right atrium. I n 5 patients the superior
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Results of SVC-PA Shunt
vena cava was also divided and an end-to-end anastomosis with the distal right pulmonary artery completed. T h e distal end of the divided superior vena cava was sutured to the side of the right pulmonary artery in 1 patient, and three weeks later a similar anastomosis was accomplished between the left pulmonary artery and a persistent left superior vena cava. In 1 patient with transposition of the great vessels and pulmonary stenosis, the SVC-PA shunt was combined with repositioning of the atrial septum to divert right pulmonary venous blood into the right atrium. T h e azygous vein was ligated in all patients, and the anastomoses were accomplished with size 5-0 continuous atraumatic silk sutures for the posterior row and size 6-0 interrupted horizontal mattress sutures for the anterior row. Since 1967, SVC-PA shunts have been attempted only in patients in whom the right pulmonary artery was at least two-thirds the size of the superior vena cava, and the superior vena cava was completely ligated only if the venous pressure remained below 30 cm. H,O; if it rose above that level, only partial ligation was carried out.
R esu 1ts Of the 31 patients operated upon, 20 were discharged from the hospital and 11 failed to survive operation. Superior vena caval syndrome was the cause of death in 8 patients and respiratory insufficiency in 3. Eight of the 11 deaths occurred in infants less than 6 months of age, including 4 under the age of 1 week. T h e youngest patient to survive was 3 weeks old at the time of operation. Superior vena caval syndrome occurred in 10 patients immediately after operation. Two patients tolerated immediate reoperation and conversion from complete to partial ligation of the superior vena cava. With more careful patient selection and keeping the vena caval pressure below 30 cm. HzO, 8 consecutive patients have been operated upon without developing this serious complication. T h e 1 death in this group was due to respiratory insufficiency. Chylothorax occurred in 7 patients, 4 of whom required thoracotomy with ligation of the thoracic duct. One patient, reoperated upon one month postoperatively for persistent chylothorax, died following decortication. Pulmonary insufficiency was not a frequent complication but did account for 3 operative deaths.
Follow-up Of the 20 patients discharged from the hospital, 3 failed to survive. As noted, 1 died one month after operation with pulmonary insufficiency following decortication for persistent right chylothorax. T h e second patient, who had transposition of the great vessels and pulmonary stenosis, developed
SAKIYALAK ET AL.
congestive heart failure and pneumonia and died eight months postoperatively following an attempt at repositioning the atrial septum. Postmortem examination was not done, but in retrospect this patient probably had less pulmonary stenosis than was originally suspected and, in reality, had transposition of the great vessels with a ventricular septa1 defect. T h e third patient died with superior vena caval syndrome following ligation of the left superior vena cava sixteen months after the original operation. Postmortem examination showed transposition of the great vessels with hypoplastic left ventricle and intact ventricular septum. In addition, pulmonary vascular disease without pulmonary stenosis was found. Seventeen patients have been followed for from one to nine years. Their growth and development have been poor, in that only 2 are in the fiftieth percentile, 8 are between the third and the twenty-fifth percentile, and 5 are below the third percentile. T h e 2 oldest patients are now 16 and 19 years of age and weigh only 50 and 54 kg., respectively. As shown in Figure 1, oxygen saturation in all patients rose and has remained above preoperative levels. Hematocrit, on the other hand, has shown less favorable changes. As shown in Figure 2, in the majority of patients hematocrit fell and remained below preoperative levels for three years. Following this period, except in 4 patients, hematocrit has risen in many patients, above the preoperative level.
CIG. I . Changes in oxygen saturation as determined from direct arterial blood measurements preoperatiuely and ear oximetry postoperatively.
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Results of SVC-PA Shunt
401
FIG. 2.
I
PREOPI
I
2
I
I
I
I
5 6 TIME IN Y E A R S 3
4
I
7
I
8
I
9
Changes in hematomit before SVC-PA shunt and during follow-up period.
Six patients have required an additional operation because of rising hematocrit and increasing cyanosis. In 1 patient, as noted above, a left-sided SVC-PA shunt was performed three weeks after the initial operation. A second infant (M. W.) underwent extrapericardial ligation of a left superior vena cava two months after her initial operation. Two and one-half years later a third operation was necessary, at which time massive venous collaterals bypassing the ligated left superior vena cava were found. This time, intrapericardial ligation of the left superior vena cava was carried out together with ligation of many collateral veins and creation of a systemic pulmonary artery shunt. A third infant (M. B.) was readmitted almost moribund six months after creation of an SVC-PA shunt. An emergency exploratory left thoracotomy was carried out, and the left superior vena cava was ligated together with creation of a systemic pulmonary artery shunt. Nine years later this patient’s hematocrit has again risen to high levels, and he will probably require an additional operation. In a fourth patient (S. S.), a partially occluded right superior vena cava was completely ligated and a left subclavian pulmonary artery shunt created six years after the initial operation. A fifth patient (B. J.) underwent left superior vena cava ligation seven years after the original operation. As shown in Figure 3, i n the sixth patient (T. W.), recent recatheterization showed excellent function of the SVC-PA shunt five and one-half years following operation. However, right ventricVOL. 12, NO.
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SAKIYALAK E T AL.
A
B
F I G . 3. (Patient T. W . )( A ) Left anlerzor oblique view of right ventricular angiogram performed Before SVC-PA shunt o n April 16, 1965. N o t e filling of pulmonary artery within arch of aorta. ( B ) Left anterior oblique view of right ventricular angiogram performed 5 % years after SVC-PA shunt. N o t e failure of pulmonary vessels t o fill. (C) Pulmonary angiogram 5% years after creation of SVC-PA shunt. Contrast material has been injected through a catheter in the SVC. All pulmonary radicals are filled without evidence of vascular obstruction.
C ular angiograms showed no filling of the left pulmonary artery, which was seen during the initial study (Fig. 3A, B). Progression of pulmonary stenosis probably accounts for failure of contrast material to fill the pulmonary vessels. In this patient, a left superior vena cava and massive venous collaterals were ligated and left pulmonary artery-to-aorta side-to-side anastomosis carried out.
Comment A superior vena cava-to-pulmonary artery shunt effectively augments pulmonary blood flow, using venous blood, without increasing the work of the heart. A systemic pulmonary artery shunt, on the other hand, increases blood flow through the lungs with mixed venous arterial blood and adds a
520
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Results of SVC-PA Shund volume workload to the left ventricle. A caval pulmonary artery shunt is not tolerated in infants below the age of 1 month, whereas systemic pulmonary artery shunts can be carried out with low mortality and morbidity in all age groups. While an SVC-PA shunt is difficult to reconstruct and requires special catheterization during cardiopulmonary bypass for later corrective surgery, a systemic pulmonary artery shunt can be readily obliterated and does not interfere with cardiopulmonary bypass. With these comparative features in mind, it is now generally agreed that a systemic pulmonary artery shunt is the procedure of choice for correctable lesions such as tetralogy of Fallot. Superior vena cava-to-pulmonary artery shunts, on the other hand, should be reserved for patients over 1 month of age with nonrepairable defects such as tricuspid atresia or other anomalies which may be correctable but entail relatively high operative risk, for example, pulmonary atresia with ventricular septa1 defect and transposition of the great vessels with pulmonary stenosis. Superior vena caval syndrome, a major cause of death following SVCPA shunt, can be prevented, as shown in our last 8 patients, if the pulmonary artery is at least two-thirds the size of the superior vena cava and the caval pressure is kept under 30 cm. H 2 0 by adjusting the degree of caval obstruction, Completion of caval ligation may be necessary at a later date, as was true for 1 of our patients six years after the initial operation. A similar experience has been reported by Gazzaniga and his associates [61. The method of Edwards and Bargeron [4]of delayed azygous vein ligation can also be used to prevent superior vena caval syndrome. Procedures other than a systemic pulmonary artery shunt may be indicated to augment the effectiveness of an SVC-PA shunt. For example, in patients with transposition of the great vessels and pulmonary stenosis, repositioning the atrial septum, as was done in 1 of our patients (H. S.) and as reported by Ehrenstein and associates [5],partially corrects this anomaly and affords excellent palliation. Our patient’s hematocrit is now 49, compared with a preoperative value of 85, and arterial saturation is 92%. He is literally asymptomatic two and one-half years after operation. Then, too, in some patients with a left superior vena cava, it may be helpful to anastomme the distal end of the divided cava to the side of the left pulmonary artery, as was done in 1 of our patients (D. O.), who has had an excellent result for three years. Bilateral superior vena cava-to-leftpulmonary artery shunts may result in longer palliation than a right-sided venous shunt alone. The initial benefit from an SVC-PA shunt may be dramatic, with fall in hematocrit and marked rise in oxygen saturation. However, in many patients the hematocrit rises and cyanosis increases after three years. Of the 13 patients in this series followed three or more years, 4 have rising hematocrits and are candidates for restudy and probable reoperation. Five have required reoperation with ligation of the left superior vena cava and collateral venous
SAKIYALAK ET AL. channels, together with creation of a systemic pulmonary artery shunt in 4. Only 4 patients continue to do exceedingly well three to nine years postoperatively without polycythemia or significant desaturation. T h e causes for shunt failure are not clear. Achtel and his associates [ll reported several patients in whom patency of the azygous vein was believed to have diverted venous return and decreased flow through the anastomosis with resultant stasis and intravascular pulmonary thrombosis. Boruchow and co-workers [3] postulated that progressive pulmonary stenosis resulted in decreased blood flow to the left lung and this, in turn, resulted in hypoxemia, pulmonary arterial vasoconstriction, polycythemia, and progressive decrease in blood flow through the superior vena cava-to-right pulmonary artery shunt. From our experience, we believe two factors account for the recurrence of polycythemia and cyanosis. One is progression of pulmonary stenosis, when present, resulting in decreased blood flow to the left lung and increased right-to-left shunt at the ventricular level. T h e other, and perhaps the most important, is the presence of a left superior vena cava or development of collateral venous channels, or both, which divert venous return away from the SVC-PA shunt. This “venous steal,” and not increased vascular resistance due to reflex vasoconstriction or vascular disease, accounts for decreased blood flow through the right lung. T h e inexorable development of collateral venous channels resulting in a “venous steal syndrome” may limit the use of the SVC-PA shunt for long-term palliation. After reviewing our ten-year experience with SVC-PA shunt in 31 patients, we have become less enthusiastic about the use of this type of shunt alone for palliation in cyanotic heart disease. Perhaps by combining this method of increasing pulmonary blood flow with venous blood together with a relatively small systemic pulmonary artery shunt, some patients with nonrepairable lesions may receive excellent palliation without increasing the work of the heart, as may result from a large systemic pulmonary artery shunt alone.
References 1. Achtel, R. A., Kaplan, S., Benzing, G., 111, and Heimsworth, J. A. Superior vena cava-right pulmonary artery anastomosis: Long-term results. Ann. T h o rac. Surg. 8:511, 1969. 2. Bakulev, A. N., and Kolesnikov, S. A. Anastomosis of the superior vena cava and pulmonary artery in the surgical treatment of certain congenital defects of the heart. J. Thorac. Cardiouasc. Surg. 37:693, 1959. 3. Boruchow, I. B., Swenson, E. W., Elliot, L. P., Bartley, T. D., Wheat, M. W., Jr., and Schiebler, G. L. Study of the mechanism of shunt failure after superior vena cava-right pulmonary artery anastomosis. J . Thorac. Cardiovasc. Surg. 60:531, 1970. 4. Edwards, W. S., and Bargeron, L. M., Jr. The superiority of the Glenn operation for tricuspid atresia in infancy and childhood. J . Thornc. Cardiouasc. Surg. 55:60, 1968.
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Results of SVC-PA Shunt 5. Ehrenstein, F. I., Ankeney, J. L., Liebman, J., and Coffin, L. H. The results of transposing the atrial septum (Edwards procedure) in patients with transposition of the great vessels. Ann. Thorac. Surg. 8:66, 1969. 6. Gazzaniga, A. B., Mansfield, P. S., Lafarge, C. G., and Gross, R. E. Late ligation of the superior vena cava following Glenn operation. J . Thorac. Cardiovasc. Surg. 60:84, 1970. 7. Glenn, W. W. L., Ordway, N. K., Talner, N. S., and Call, E. P. Circulatory bypass of the right side of the heart: Report of clinical application in the thirty eight cases. Circulation 31: 172, 1965. 8. Glenn, W. W. L., and Patino, J. F. Circulatory bypass of the right heart. Yule J. Biol. Med. 27:147, 1954. 9. Martin, S. P., Anabtawi, I. N., Selmonosky, C. A., Folger, G. M., Ellison, L. T., and Ellison, R. G. Long-term follow-up after superior vena cava-right pulmonary artery anastomosis. Ann. Thorac. Surg. 9:339, 1970. 10. Robicsek, F., Temesvari, A., and Kadar, R. L. A new method for the treatment of congenital heart disease associated with impaired pulmonary circulation. Actu Med. Scand. 154:151, 1956. 11. Young, W. G., Jr., and Flemma, R. J. Status of caval pulmonary anastomosis. Dis. Chest 50:87, 1966.
Discussion DR. W. STERLING EDWARDS (Albuquerque, N.Mex.): T h e long-term studies on this operation are very important. We have found some moderate differences, however, in our own long-term follow-up, and our general conclusions are not quite the same as those of the group i n Cleveland. We also have found that this operation can be carried out safely in infants over 3 months of age if, as Dr. Sakiyalak said, the venous pressure in the superior vena cava is kept from rising above 30 cm. H,O either by partially ligating the vena cava, or, as we prefer, by leaving the azygous vein temporarily open and pulling up the thread to the subcutaneous tissue three or four days to a week postoperatively. If you don't allow the caval pressure to rise above 30 cm., as has been pointed out, you can get away without SVC obstruction even in very small children. T h e long-term follow-up studies that we carried out recently showed results a little different from those of the Cleveland group. We had 2 late deaths, 1 of which occurred three months after operation. I t was sudden and unexpected, and we do not know the cause. T h e other late death was that of a child with single ventricle and pulmonary atresia who died three years after operation of tricuspid insufficiency. T h e number of long-term survivors up to ten years was 29. About 9 of these patients had an excellent result. By excellent we mean that the patient had only very mild cyanosis and excellent exercise tolerance. A good result consisted of moderate cyanosis and only moderate exercise tolerance. But the difference in our follow-up from that in Cleveland was that only 1 of these patients developed any progressive cyanosis in the late followu p period. This child was one of the original group having an excellent
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SAKIYALAK E T AL.
result, and three years later he began to have increasing cyanosis, andlike the Cleveland group-follow-up roentgenograms showed that he had developed collaterals in his left mediastinum. After ligation of these collaterals, he regained his excellent status and has maintained it since. We still believe that this is the ideal procedure for patients with uncorrectable cyanotic lesions of the right heart because it does impose less strain on the heart and can be tolerated. I wonder if the difference in our results and those of the Cleveland group may have something to do with the construction of the anastomosis itself. Our original concern about this operation was whether the anastomosis, subject to this low venous pressure, would grow enough; and we have been pleasantly surprised to find that anastomotic growth does seem to keep pace pretty well with the growth of the child. We very carefully place the anastomosis on the lateral side of the vena cava to avoid any kinking, and we carry out the entire anastomosis using interrupted sutures. I noticed in the Cleveland group’s presentation that the posterior row was done with continuous sutures and the anterior row with horizontal mattress sutures. I don’t know, but I wonder if this may have slightly restricted the growth. Finally, we have also found-and are in complete agreement with the Cleveland workers-that this is the ideal procedure in patients with transposition of the great vessels, pulmonary stenosis and ventricular septa1 defect, or a combination of superior vena cava shunt and shift to the septum. We have 2 such patients now who have maintained oxygen saturation above 90% for three and four years after operation, respectively.
DR.GEORGE A. TRUSLER (Toronto, Ont., Canada): I wish to congratulate the authors on their paper and to encourage them to continue using the superior vena cava-to-pulmonary artery shunt in treating cyanotic heart disease. I think, however, that we must resist the tendency to use this anastomosis too broadly at too young an age. I n our series of 58 cava-to-pulmonary artery anastomoses, 2 of 3 children less than 6 months of age died, whereas of 55 children over 6 months old at operation there were only 4 deaths. Serious elevation of superior vena cava pressure has been uncommon using the anastomosis at that age. T h e long-term results have been good, with only 4 of the 52 survivors needing a further operation as long as nine years postoperatively. Perhaps the difference in late results is related to this later age at operation. We have been particularly impressed by the degree of palliation obtained with the combination of a systemic arterial shunt on the left and a cava-to-pulmonary artery shunt on the right. There were 8 patients with a previous systemic arterial shunt-3 Potts, 3 right Blalock, 1 combination Blalock and Potts, and 1 Waterston. Perhaps this combination will afford 524
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Results of SVC-PA Shunt optimum palliation for children and young adults with essentially uncorrectable lesions such as tricuspid atresia, if our basic philosophy with tricuspid atresia is that we wish to have optimum oxygen saturation with the least pulmonary blood flow. The addition of a caval pulmonary anastomosis to a right Blalock shunt in 3 children, while maintaining flow into the left lung through the Blalock shunt, was effective but was difficult due to vascular pleural adhesions. T h e original systemic artery shunt should be constructed on the left. DR. GAETANO AZZOLINA (Massa, Italy): Nine patients with tricuspid atresia were operated upon, using a modified technique in diverting systemic venous drainage into both lungs, in an attempt to reduce superior vena cava syndrome and obtain better physiological results. Six are alive and improved. Only 2 patients displayed swelling, which lasted a few hours. We first ascertained that no persistent left superior vena cava was present, catheterizing cyanotic children through the left basilic or internal jugular vein. Then we ligated the azygous vein and ascertained adequacy of the caliber of the right pulmonary artery. T h e superior vena cava was rotated anteriorly; a partial exclusion clamp was applied, pulling the pulmonary artery so as to make the anastomosis as proximal as possible. Then we performed the anastomosis. Sutures were continuous in the posterior row and interrupted anteriorly, to allow growth. T h e superior vena cava was occluded proximal to the atrium with a double row of sutures, leaving about 3 mm. patent superiorly. Around the patent portion, a double loop of silk was loosely placed. T h e ends were brought to the skin through the shortest distance and tightened seven to fifteen days later. Angiocardiograms show diversion of blood flow into both lungs. DR. FRANCIS ROBICSEK (Charlotte, N.C.): If we d o this operation-and we are doing fewer and fewer of them-we have to realize that it is a oneshot deal and you have to put all the cards on the table. I couldn’t help noticing the large number of left superior vena cavas that were either left open deliberately or overlooked. I think if someone performs a cava-to-pulmonary artery anastomosis, the left superior vena cava should be searched for. If it is left open or the right superior vena cava is only partially ligated, all the blood will be sucked out, even from the right lung, and reversal of the shunt can result. If somebody wants to proceed cautiously, I certainly would recommend the method of Dr. Sterling Edwards, which is safe and allows for further operation later on. I think cava-to-pulmonary artery anastomosis has a very, very limited use today, and as open-heart surgery progresses, it will most likely completely disappear. I also want to mention the name of Dr. Carlo A. Carlon, Professor of
SAKIYALAK ET AL. Surgery at Padua, Italy, who developed this operation and whose name has been very frequently, if not always, neglected.
DR. ANKENEY: I wish to thank the discussants for their pertinent remarks and apologize to the audience for the disparity between the abstract appearing in the program and the results we presented today. As we analyzed our results, we were initially favorably impressed by the oxygen saturation data, which showed a continual rise in all patients. However, as you heard, in many patients the hematocrit rose significantly after about three years. Further analysis indicated that this evidence of deterioration probably resulted from the development of collateral venous beds with “steal” from the vena cava-to-pulmonary artery shunt. Therefore, as noted, many of our patients required a second operation to attain satisfactory palliation. As a result of this study, we no longer attempt superior vena cava-topulmonary artery shunts in children under 3 months of age and select only those patients with a favorable pulmonary artery-superior vena cava size relationship. It is our belief now that in most patients, a systemic pulmonary artery shunt will probably be needed as an adjunct to venous pulmonary artery shunts in order to attain satisfactory palliation in patients with nonrepairable cyanotic heart defects. I n certain specific instances, other procedures such as repositioning of the atrial septum may be combined with superior vena cava-to-pulmonary artery shunt to attain excellent palliation.
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S
uperior vena cava-to-pulmonary artery shunt for the palliative treatment of congenital cyanotic heart disease with decreased pulmonary circulation was introduced independently by Glenn [8], Robicsek [lo], and Bakulev [Z] and their colleagues. This method for increasing pulmonary blood flow using venous blood results in excellent initial palliation [4,7, 111. However, the type of cyanotic heart disease best treated by this method remains unclear, and relatively few long-term results have been reported [l, 3, 91. Therefore, we reviewed our experience with 31 patients in whom an SVC-PA shunt operation was performed during the past ten years, and the results of this study are herein reported.
Clinical Materials and Methods A superior vena cava-to-pulmonary artery shunt operation was performed in 31 patients with cyanotic heart lesions as listed in the Table. From the Departments of Thoracic Surgery and Pediatric Cardiology, University Hospitals of Cleveland, Cleveland, Ohio. Presented at the Seventh Annual Meeting of The Society of Thoracic Surgeons, Dallas, Tex., Jan. 18-20, 1971. Address reprint requests to Dr. Ankeney, University Hospitals of Cleveland, 2065 Adelbert Rd., Cleveland, Ohio 44106.
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THE ANNALS OF THORACIC SURGERY
Results of SVC-PA Shunt RESULTS IN 31 PATIENTS UNDERGOING S V C P A SHUNT OPERATION
Patient Sex & Age
Date of Operation
W.S.
M, 10yr.
5/16/61
M.B.
M, 3wk.
12/15/61
P. S.
M, 1Gyr.
1/25/62
A.D.
F, 3yr.
4/25/62
R.S.
M, 3?4yr.
6/20/62
N.V.
M, 3?4mo.
7/11/62
S.S.
M, l%yr.
11/8/62
B. J.
F, 1 yr.
4/1/63
B.B.
F, 7mo.
6/6/63
D.F.
M, 2mo.
7/22/63
A.D.
M, 2mo.
1/14/64
J.C.
M, 4?4mo.
214164
R.G.
M, 10yr.
6/9/64
B. S.
F, 5mo.
71 13/64
W . M . M, 4?hmo.
11/4/64
D.T.
F, 2mo.
11/20/64
R.W.
M, 2days
12/19/64
R.L.
M, 4days
12/29/64
Diagnosis T G V with pulmonary stenosis Pulmonary atresia with VSD Dextrocardia with pulmonary atresia PC common A-V valve Tricuspid atresia Dextrocardia with VSD, pulmonary atresia, & hypoplastic RV T G V with pulmonary stenosis Tricuspid atresia
Dextrocardia with pulmonary atresia & VSD, PDA Tricuspid atresia Pulmonary atresia & VSD T G V with pulmonary stenosis Pulmonary atresia & VSD Pulmonary atresia & VSD T G V & pulmonary stenosis Hypoplastic RV with pulmonary atresia & intact ventricular septum T G V & pulmonary stenosis T G V & pulmonary stenosis Hypoplastic RV with pulmonary atresia & intact ventricular septum
Result Good
Good after ligation of left SVC & left Blalock 6 mo. later Death-respiratory insufficiency Death-SVC syndrome Late death 1 mo. postop. Death-SVC syndrome Good after complete ligation of SVC & left Blalock 6 yr. later Good after ligation of left SVC 7 yr. later Death-SVC drome Death-SVC drome Good except Hct. Death-SVC drome Good
synsynrising syn-
Late death 8 mo. postop. Dea th-respiratory insufficiency Good except rising Hct. Death-SVC syndrome Death-SVC syndrome
SAKIYALAK E T AL. TABLE (Continued)
Patient Sex &Age
Date of Operation
T.W.
M, 8mo.
4/ 16f 65
M. E.
F, 6mo.
9/7/65
J.A.
F, 2mo.
R. E.
M, l%yr.
G.G.
F, 5days
D.O.
F, 2%mo.
TGV & pulmonary stenosis 11/18/65 TGV with intact ventricular septum & hypoplastic LV 1017166 Pulmonary atresia & VSD 12/6/66 Double-outlet RV with pulmonary atresia 4/21/67 Tricuspid atresia
D. E. K. J. M.W.
F, 4mo. M, 8mo. F, lmo.
7/13/67 9/7/67 2/5/68
H. S.
M, 6yr.
7/9/68
L. B.
F, 6mo.
R.H.
M, 3mo.
K.B.
M, 2days
Diagnosis TGV k pulmonary stenosis
Tricuspid atresia Tricuspid atresia Pulmonary atresia & VSD
TGV with pulmonary stenosis 2/27/69 TGV with pulmonary stenosis 1/15/70 TGV with pulmonary stenosis 4/4/70 Hypoplastic RV with pulmonary atresia & intact ventricular septum
Result Good after ligation of left SVC & aorta-toleft PA shunt 5% yr. later Good except rising Hct. Late death 16 mo. postop. Good except rising Hct. Death-SVC syndrome Good after left SVCPA shunt 3 wk. later Good Good Good after ligation left SVC 2 mo. later & left Blalock 2% yr. later Good Good except rising Hct. Good Death-respira tory insufficiency
T G V = transposition of great vessels; VSD = ventricular septal defect; RV = right ventricle; PDA = patent ductus arteriosus; Hct. = hematocrit; LV = left ventricle.
Twelve patients had transposition of the great vessels with pulmonary stenosis, 6 had tricuspid atresia, 6 had pulmonary atresia with ventricular septal defect, 3 had pulmonary atresia with hypoplastic right ventricle and intact ventricular septum, 3 had dextrocardia with complicated intracardiac anomalies, and 1 had double-outlet right ventricle with pulmonary atresia. There were 18 male and 13 female patients. T h e ages ranged from 2 days to 10 years with 19 of the patients 6 months of age or less. I n 25 patients the distal end of the divided right pulmonary artery was sutured to the side of the superior vena cava, which was completely or partially ligated at its junction with the right atrium. I n 5 patients the superior
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Results of SVC-PA Shunt
vena cava was also divided and an end-to-end anastomosis with the distal right pulmonary artery completed. T h e distal end of the divided superior vena cava was sutured to the side of the right pulmonary artery in 1 patient, and three weeks later a similar anastomosis was accomplished between the left pulmonary artery and a persistent left superior vena cava. In 1 patient with transposition of the great vessels and pulmonary stenosis, the SVC-PA shunt was combined with repositioning of the atrial septum to divert right pulmonary venous blood into the right atrium. T h e azygous vein was ligated in all patients, and the anastomoses were accomplished with size 5-0 continuous atraumatic silk sutures for the posterior row and size 6-0 interrupted horizontal mattress sutures for the anterior row. Since 1967, SVC-PA shunts have been attempted only in patients in whom the right pulmonary artery was at least two-thirds the size of the superior vena cava, and the superior vena cava was completely ligated only if the venous pressure remained below 30 cm. H,O; if it rose above that level, only partial ligation was carried out.
R esu 1ts Of the 31 patients operated upon, 20 were discharged from the hospital and 11 failed to survive operation. Superior vena caval syndrome was the cause of death in 8 patients and respiratory insufficiency in 3. Eight of the 11 deaths occurred in infants less than 6 months of age, including 4 under the age of 1 week. T h e youngest patient to survive was 3 weeks old at the time of operation. Superior vena caval syndrome occurred in 10 patients immediately after operation. Two patients tolerated immediate reoperation and conversion from complete to partial ligation of the superior vena cava. With more careful patient selection and keeping the vena caval pressure below 30 cm. HzO, 8 consecutive patients have been operated upon without developing this serious complication. T h e 1 death in this group was due to respiratory insufficiency. Chylothorax occurred in 7 patients, 4 of whom required thoracotomy with ligation of the thoracic duct. One patient, reoperated upon one month postoperatively for persistent chylothorax, died following decortication. Pulmonary insufficiency was not a frequent complication but did account for 3 operative deaths.
Follow-up Of the 20 patients discharged from the hospital, 3 failed to survive. As noted, 1 died one month after operation with pulmonary insufficiency following decortication for persistent right chylothorax. T h e second patient, who had transposition of the great vessels and pulmonary stenosis, developed
SAKIYALAK ET AL.
congestive heart failure and pneumonia and died eight months postoperatively following an attempt at repositioning the atrial septum. Postmortem examination was not done, but in retrospect this patient probably had less pulmonary stenosis than was originally suspected and, in reality, had transposition of the great vessels with a ventricular septa1 defect. T h e third patient died with superior vena caval syndrome following ligation of the left superior vena cava sixteen months after the original operation. Postmortem examination showed transposition of the great vessels with hypoplastic left ventricle and intact ventricular septum. In addition, pulmonary vascular disease without pulmonary stenosis was found. Seventeen patients have been followed for from one to nine years. Their growth and development have been poor, in that only 2 are in the fiftieth percentile, 8 are between the third and the twenty-fifth percentile, and 5 are below the third percentile. T h e 2 oldest patients are now 16 and 19 years of age and weigh only 50 and 54 kg., respectively. As shown in Figure 1, oxygen saturation in all patients rose and has remained above preoperative levels. Hematocrit, on the other hand, has shown less favorable changes. As shown in Figure 2, in the majority of patients hematocrit fell and remained below preoperative levels for three years. Following this period, except in 4 patients, hematocrit has risen in many patients, above the preoperative level.
CIG. I . Changes in oxygen saturation as determined from direct arterial blood measurements preoperatiuely and ear oximetry postoperatively.
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Results of SVC-PA Shunt
401
FIG. 2.
I
PREOPI
I
2
I
I
I
I
5 6 TIME IN Y E A R S 3
4
I
7
I
8
I
9
Changes in hematomit before SVC-PA shunt and during follow-up period.
Six patients have required an additional operation because of rising hematocrit and increasing cyanosis. In 1 patient, as noted above, a left-sided SVC-PA shunt was performed three weeks after the initial operation. A second infant (M. W.) underwent extrapericardial ligation of a left superior vena cava two months after her initial operation. Two and one-half years later a third operation was necessary, at which time massive venous collaterals bypassing the ligated left superior vena cava were found. This time, intrapericardial ligation of the left superior vena cava was carried out together with ligation of many collateral veins and creation of a systemic pulmonary artery shunt. A third infant (M. B.) was readmitted almost moribund six months after creation of an SVC-PA shunt. An emergency exploratory left thoracotomy was carried out, and the left superior vena cava was ligated together with creation of a systemic pulmonary artery shunt. Nine years later this patient’s hematocrit has again risen to high levels, and he will probably require an additional operation. In a fourth patient (S. S.), a partially occluded right superior vena cava was completely ligated and a left subclavian pulmonary artery shunt created six years after the initial operation. A fifth patient (B. J.) underwent left superior vena cava ligation seven years after the original operation. As shown in Figure 3, i n the sixth patient (T. W.), recent recatheterization showed excellent function of the SVC-PA shunt five and one-half years following operation. However, right ventricVOL. 12, NO.
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SAKIYALAK E T AL.
A
B
F I G . 3. (Patient T. W . )( A ) Left anlerzor oblique view of right ventricular angiogram performed Before SVC-PA shunt o n April 16, 1965. N o t e filling of pulmonary artery within arch of aorta. ( B ) Left anterior oblique view of right ventricular angiogram performed 5 % years after SVC-PA shunt. N o t e failure of pulmonary vessels t o fill. (C) Pulmonary angiogram 5% years after creation of SVC-PA shunt. Contrast material has been injected through a catheter in the SVC. All pulmonary radicals are filled without evidence of vascular obstruction.
C ular angiograms showed no filling of the left pulmonary artery, which was seen during the initial study (Fig. 3A, B). Progression of pulmonary stenosis probably accounts for failure of contrast material to fill the pulmonary vessels. In this patient, a left superior vena cava and massive venous collaterals were ligated and left pulmonary artery-to-aorta side-to-side anastomosis carried out.
Comment A superior vena cava-to-pulmonary artery shunt effectively augments pulmonary blood flow, using venous blood, without increasing the work of the heart. A systemic pulmonary artery shunt, on the other hand, increases blood flow through the lungs with mixed venous arterial blood and adds a
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Results of SVC-PA Shund volume workload to the left ventricle. A caval pulmonary artery shunt is not tolerated in infants below the age of 1 month, whereas systemic pulmonary artery shunts can be carried out with low mortality and morbidity in all age groups. While an SVC-PA shunt is difficult to reconstruct and requires special catheterization during cardiopulmonary bypass for later corrective surgery, a systemic pulmonary artery shunt can be readily obliterated and does not interfere with cardiopulmonary bypass. With these comparative features in mind, it is now generally agreed that a systemic pulmonary artery shunt is the procedure of choice for correctable lesions such as tetralogy of Fallot. Superior vena cava-to-pulmonary artery shunts, on the other hand, should be reserved for patients over 1 month of age with nonrepairable defects such as tricuspid atresia or other anomalies which may be correctable but entail relatively high operative risk, for example, pulmonary atresia with ventricular septa1 defect and transposition of the great vessels with pulmonary stenosis. Superior vena caval syndrome, a major cause of death following SVCPA shunt, can be prevented, as shown in our last 8 patients, if the pulmonary artery is at least two-thirds the size of the superior vena cava and the caval pressure is kept under 30 cm. H 2 0 by adjusting the degree of caval obstruction, Completion of caval ligation may be necessary at a later date, as was true for 1 of our patients six years after the initial operation. A similar experience has been reported by Gazzaniga and his associates [61. The method of Edwards and Bargeron [4]of delayed azygous vein ligation can also be used to prevent superior vena caval syndrome. Procedures other than a systemic pulmonary artery shunt may be indicated to augment the effectiveness of an SVC-PA shunt. For example, in patients with transposition of the great vessels and pulmonary stenosis, repositioning the atrial septum, as was done in 1 of our patients (H. S.) and as reported by Ehrenstein and associates [5],partially corrects this anomaly and affords excellent palliation. Our patient’s hematocrit is now 49, compared with a preoperative value of 85, and arterial saturation is 92%. He is literally asymptomatic two and one-half years after operation. Then, too, in some patients with a left superior vena cava, it may be helpful to anastomme the distal end of the divided cava to the side of the left pulmonary artery, as was done in 1 of our patients (D. O.), who has had an excellent result for three years. Bilateral superior vena cava-to-leftpulmonary artery shunts may result in longer palliation than a right-sided venous shunt alone. The initial benefit from an SVC-PA shunt may be dramatic, with fall in hematocrit and marked rise in oxygen saturation. However, in many patients the hematocrit rises and cyanosis increases after three years. Of the 13 patients in this series followed three or more years, 4 have rising hematocrits and are candidates for restudy and probable reoperation. Five have required reoperation with ligation of the left superior vena cava and collateral venous
SAKIYALAK ET AL. channels, together with creation of a systemic pulmonary artery shunt in 4. Only 4 patients continue to do exceedingly well three to nine years postoperatively without polycythemia or significant desaturation. T h e causes for shunt failure are not clear. Achtel and his associates [ll reported several patients in whom patency of the azygous vein was believed to have diverted venous return and decreased flow through the anastomosis with resultant stasis and intravascular pulmonary thrombosis. Boruchow and co-workers [3] postulated that progressive pulmonary stenosis resulted in decreased blood flow to the left lung and this, in turn, resulted in hypoxemia, pulmonary arterial vasoconstriction, polycythemia, and progressive decrease in blood flow through the superior vena cava-to-right pulmonary artery shunt. From our experience, we believe two factors account for the recurrence of polycythemia and cyanosis. One is progression of pulmonary stenosis, when present, resulting in decreased blood flow to the left lung and increased right-to-left shunt at the ventricular level. T h e other, and perhaps the most important, is the presence of a left superior vena cava or development of collateral venous channels, or both, which divert venous return away from the SVC-PA shunt. This “venous steal,” and not increased vascular resistance due to reflex vasoconstriction or vascular disease, accounts for decreased blood flow through the right lung. T h e inexorable development of collateral venous channels resulting in a “venous steal syndrome” may limit the use of the SVC-PA shunt for long-term palliation. After reviewing our ten-year experience with SVC-PA shunt in 31 patients, we have become less enthusiastic about the use of this type of shunt alone for palliation in cyanotic heart disease. Perhaps by combining this method of increasing pulmonary blood flow with venous blood together with a relatively small systemic pulmonary artery shunt, some patients with nonrepairable lesions may receive excellent palliation without increasing the work of the heart, as may result from a large systemic pulmonary artery shunt alone.
References 1. Achtel, R. A., Kaplan, S., Benzing, G., 111, and Heimsworth, J. A. Superior vena cava-right pulmonary artery anastomosis: Long-term results. Ann. T h o rac. Surg. 8:511, 1969. 2. Bakulev, A. N., and Kolesnikov, S. A. Anastomosis of the superior vena cava and pulmonary artery in the surgical treatment of certain congenital defects of the heart. J. Thorac. Cardiouasc. Surg. 37:693, 1959. 3. Boruchow, I. B., Swenson, E. W., Elliot, L. P., Bartley, T. D., Wheat, M. W., Jr., and Schiebler, G. L. Study of the mechanism of shunt failure after superior vena cava-right pulmonary artery anastomosis. J . Thorac. Cardiovasc. Surg. 60:531, 1970. 4. Edwards, W. S., and Bargeron, L. M., Jr. The superiority of the Glenn operation for tricuspid atresia in infancy and childhood. J . Thornc. Cardiouasc. Surg. 55:60, 1968.
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Results of SVC-PA Shunt 5. Ehrenstein, F. I., Ankeney, J. L., Liebman, J., and Coffin, L. H. The results of transposing the atrial septum (Edwards procedure) in patients with transposition of the great vessels. Ann. Thorac. Surg. 8:66, 1969. 6. Gazzaniga, A. B., Mansfield, P. S., Lafarge, C. G., and Gross, R. E. Late ligation of the superior vena cava following Glenn operation. J . Thorac. Cardiovasc. Surg. 60:84, 1970. 7. Glenn, W. W. L., Ordway, N. K., Talner, N. S., and Call, E. P. Circulatory bypass of the right side of the heart: Report of clinical application in the thirty eight cases. Circulation 31: 172, 1965. 8. Glenn, W. W. L., and Patino, J. F. Circulatory bypass of the right heart. Yule J. Biol. Med. 27:147, 1954. 9. Martin, S. P., Anabtawi, I. N., Selmonosky, C. A., Folger, G. M., Ellison, L. T., and Ellison, R. G. Long-term follow-up after superior vena cava-right pulmonary artery anastomosis. Ann. Thorac. Surg. 9:339, 1970. 10. Robicsek, F., Temesvari, A., and Kadar, R. L. A new method for the treatment of congenital heart disease associated with impaired pulmonary circulation. Actu Med. Scand. 154:151, 1956. 11. Young, W. G., Jr., and Flemma, R. J. Status of caval pulmonary anastomosis. Dis. Chest 50:87, 1966.
Discussion DR. W. STERLING EDWARDS (Albuquerque, N.Mex.): T h e long-term studies on this operation are very important. We have found some moderate differences, however, in our own long-term follow-up, and our general conclusions are not quite the same as those of the group i n Cleveland. We also have found that this operation can be carried out safely in infants over 3 months of age if, as Dr. Sakiyalak said, the venous pressure in the superior vena cava is kept from rising above 30 cm. H,O either by partially ligating the vena cava, or, as we prefer, by leaving the azygous vein temporarily open and pulling up the thread to the subcutaneous tissue three or four days to a week postoperatively. If you don't allow the caval pressure to rise above 30 cm., as has been pointed out, you can get away without SVC obstruction even in very small children. T h e long-term follow-up studies that we carried out recently showed results a little different from those of the Cleveland group. We had 2 late deaths, 1 of which occurred three months after operation. I t was sudden and unexpected, and we do not know the cause. T h e other late death was that of a child with single ventricle and pulmonary atresia who died three years after operation of tricuspid insufficiency. T h e number of long-term survivors up to ten years was 29. About 9 of these patients had an excellent result. By excellent we mean that the patient had only very mild cyanosis and excellent exercise tolerance. A good result consisted of moderate cyanosis and only moderate exercise tolerance. But the difference in our follow-up from that in Cleveland was that only 1 of these patients developed any progressive cyanosis in the late followu p period. This child was one of the original group having an excellent
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SAKIYALAK E T AL.
result, and three years later he began to have increasing cyanosis, andlike the Cleveland group-follow-up roentgenograms showed that he had developed collaterals in his left mediastinum. After ligation of these collaterals, he regained his excellent status and has maintained it since. We still believe that this is the ideal procedure for patients with uncorrectable cyanotic lesions of the right heart because it does impose less strain on the heart and can be tolerated. I wonder if the difference in our results and those of the Cleveland group may have something to do with the construction of the anastomosis itself. Our original concern about this operation was whether the anastomosis, subject to this low venous pressure, would grow enough; and we have been pleasantly surprised to find that anastomotic growth does seem to keep pace pretty well with the growth of the child. We very carefully place the anastomosis on the lateral side of the vena cava to avoid any kinking, and we carry out the entire anastomosis using interrupted sutures. I noticed in the Cleveland group’s presentation that the posterior row was done with continuous sutures and the anterior row with horizontal mattress sutures. I don’t know, but I wonder if this may have slightly restricted the growth. Finally, we have also found-and are in complete agreement with the Cleveland workers-that this is the ideal procedure in patients with transposition of the great vessels, pulmonary stenosis and ventricular septa1 defect, or a combination of superior vena cava shunt and shift to the septum. We have 2 such patients now who have maintained oxygen saturation above 90% for three and four years after operation, respectively.
DR.GEORGE A. TRUSLER (Toronto, Ont., Canada): I wish to congratulate the authors on their paper and to encourage them to continue using the superior vena cava-to-pulmonary artery shunt in treating cyanotic heart disease. I think, however, that we must resist the tendency to use this anastomosis too broadly at too young an age. I n our series of 58 cava-to-pulmonary artery anastomoses, 2 of 3 children less than 6 months of age died, whereas of 55 children over 6 months old at operation there were only 4 deaths. Serious elevation of superior vena cava pressure has been uncommon using the anastomosis at that age. T h e long-term results have been good, with only 4 of the 52 survivors needing a further operation as long as nine years postoperatively. Perhaps the difference in late results is related to this later age at operation. We have been particularly impressed by the degree of palliation obtained with the combination of a systemic arterial shunt on the left and a cava-to-pulmonary artery shunt on the right. There were 8 patients with a previous systemic arterial shunt-3 Potts, 3 right Blalock, 1 combination Blalock and Potts, and 1 Waterston. Perhaps this combination will afford 524
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Results of SVC-PA Shunt optimum palliation for children and young adults with essentially uncorrectable lesions such as tricuspid atresia, if our basic philosophy with tricuspid atresia is that we wish to have optimum oxygen saturation with the least pulmonary blood flow. The addition of a caval pulmonary anastomosis to a right Blalock shunt in 3 children, while maintaining flow into the left lung through the Blalock shunt, was effective but was difficult due to vascular pleural adhesions. T h e original systemic artery shunt should be constructed on the left. DR. GAETANO AZZOLINA (Massa, Italy): Nine patients with tricuspid atresia were operated upon, using a modified technique in diverting systemic venous drainage into both lungs, in an attempt to reduce superior vena cava syndrome and obtain better physiological results. Six are alive and improved. Only 2 patients displayed swelling, which lasted a few hours. We first ascertained that no persistent left superior vena cava was present, catheterizing cyanotic children through the left basilic or internal jugular vein. Then we ligated the azygous vein and ascertained adequacy of the caliber of the right pulmonary artery. T h e superior vena cava was rotated anteriorly; a partial exclusion clamp was applied, pulling the pulmonary artery so as to make the anastomosis as proximal as possible. Then we performed the anastomosis. Sutures were continuous in the posterior row and interrupted anteriorly, to allow growth. T h e superior vena cava was occluded proximal to the atrium with a double row of sutures, leaving about 3 mm. patent superiorly. Around the patent portion, a double loop of silk was loosely placed. T h e ends were brought to the skin through the shortest distance and tightened seven to fifteen days later. Angiocardiograms show diversion of blood flow into both lungs. DR. FRANCIS ROBICSEK (Charlotte, N.C.): If we d o this operation-and we are doing fewer and fewer of them-we have to realize that it is a oneshot deal and you have to put all the cards on the table. I couldn’t help noticing the large number of left superior vena cavas that were either left open deliberately or overlooked. I think if someone performs a cava-to-pulmonary artery anastomosis, the left superior vena cava should be searched for. If it is left open or the right superior vena cava is only partially ligated, all the blood will be sucked out, even from the right lung, and reversal of the shunt can result. If somebody wants to proceed cautiously, I certainly would recommend the method of Dr. Sterling Edwards, which is safe and allows for further operation later on. I think cava-to-pulmonary artery anastomosis has a very, very limited use today, and as open-heart surgery progresses, it will most likely completely disappear. I also want to mention the name of Dr. Carlo A. Carlon, Professor of
SAKIYALAK ET AL. Surgery at Padua, Italy, who developed this operation and whose name has been very frequently, if not always, neglected.
DR. ANKENEY: I wish to thank the discussants for their pertinent remarks and apologize to the audience for the disparity between the abstract appearing in the program and the results we presented today. As we analyzed our results, we were initially favorably impressed by the oxygen saturation data, which showed a continual rise in all patients. However, as you heard, in many patients the hematocrit rose significantly after about three years. Further analysis indicated that this evidence of deterioration probably resulted from the development of collateral venous beds with “steal” from the vena cava-to-pulmonary artery shunt. Therefore, as noted, many of our patients required a second operation to attain satisfactory palliation. As a result of this study, we no longer attempt superior vena cava-topulmonary artery shunts in children under 3 months of age and select only those patients with a favorable pulmonary artery-superior vena cava size relationship. It is our belief now that in most patients, a systemic pulmonary artery shunt will probably be needed as an adjunct to venous pulmonary artery shunts in order to attain satisfactory palliation in patients with nonrepairable cyanotic heart defects. I n certain specific instances, other procedures such as repositioning of the atrial septum may be combined with superior vena cava-to-pulmonary artery shunt to attain excellent palliation.
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