Aorta-to-Right Pulmonary Artery Anastomosis Causing Obstruction of the Right Pulmonary Artery

Transcription

1 Aorta-to-Right Pulmonary Artery Anastomosis Causing Obstruction of the Right Pulmonary Artery Management During Correction of Tetralogy of Fallot William A. Gay, Jr., M.D., and Paul A. Ebert, M.D. ABSTRACT Sixteen of 18 patients undergoing intracardiac repair of tetralogy of Fallot following ascending aorta-to-right pulmonary artery shunt procedures required patch reconstruction of the right pulmonary artery because of significant obstruction at the site of the shunt. Patch reconstruction was required in all patients having had shunts done at less than 1 year of age. The operative mortality in this group of patients was higher than that in patients undergoing repair of tetralogy alone or repair plus ligation of a prior Blalock-Taussig shunt, but it was lower than that associated with repair plus obliteration of a previous Potts anastomosis. The ascending aorta-to-right pulmonary artery shunt appears to be the best procedure for palliation of severely symptomatic infants with tetralogy in whom the anatomy is not suitable for either primary repair or a subclavian-to-pulmonary artery shunt. Cardiac catheterization and angiocardiography should be performed prior to subsequent total correction to demonstrate the direction of flow and the anatomical configuration of the right pulmonary artery. T he aorta-to-right pulmonary artery anastomosis described by Waterston [31] is frequently used [2, 11, 13, 14, 16-18, 20, 24, 26-28, 301 to increase pulmonary blood flow in infants with severe forms of tetralogy of Fallot or other types of cyanotic congenital heart disease with decreased pulmonary flow. In the small infant, a more satisfactory anastomosis can usually be established with this procedure than with the Blalock-Taussig operation [8] since the subclavian artery is often quite small. A presumed advantage of the Waterston procedure over the Potts operation [23] is the supposed ease of closing the shunt at the time of intracardiac repair [ 11, 12, 181. A previous subclavian-to-pulmonary artery anastomosis does not affect the mortality or morbidity of intracardiac repair of tetralogy [15]; however, correction following a prior Potts procedure has From the Department of Surgery, New York HospitalCornell Medical Center, New York, N.Y. Presented at the Ninth Annual Meeting of The Society of Thoracic Surgeons, Houston, Tex., Jan , Address,reprint requests to Dr. Gay, Department of Surgery, New York Hospital-Corncll Medical Center, 525 E. 68th St., New York, N.Y THE ANNALS OF THORACIC SURGERY

2 Obstruction After Aorta-to-Right Pulmonary Artery Shunt been associated with an increased operative mortality [6, 10, 261. The purpose of this communication is to report our experience with intracardiac repair of tetralogy of Fallot in 18 children who had previously undergone Waterston operations. Materials and Methods Eighteen patients with Waterston shunts underwent intracardiac repair of tetralogy of Fallot at 3 to 16 years of age. There were 2 hospital deaths in this group. One patient with pseudo truncus arteriosus died in the operating room following an attempt at reconstruction of the pulmonary artery. In addition to complete occlusion of the right pulmonary artery at the site of the shunt, this child had a markedly hypoplastic left pulmonary artery and complete atresia of the main pulmonary artery and valve. The other death was that of a patient who had sustained intraoperative brain damage and died 24 hours postoperatively. The remaining 16 patients were discharged improved after operation. All 18 patients had had confirmation of the diagnosis of tetralogy by cardiac catheterization and angiocardiography prior to their shunt procedures (Fig. 1). Catheterization and angiocardiography were repeated prior to open correction. Deformity of the right main pulmonary artery was noted in 15 of the 18 patients; the deformity ranged from mild kinking in 3 to complete occlusion in 12 (Fig. 2). In each of these 15 patients a pericardial patch was required to reconstruct the right pulmonary artery. In 1 additional patient without angiographic deformity of the right pulmonary artery, a fibrous ridge on the posterior wall of the right pulmonary artery was A FIG. 1. Typical frontal (A) and lateral (B) views of a right ventriculogram in tetralogy of Fallot prior to any operative intervention. B VOL. 16, NO. 4, OCTOBER,

3 GAY AND EBERT C D FIG. 2. Angiography following Waterston shunt. Pulmonary arteriogram (A, frontal; B, lateral) demonstrates total diversion of pulmonary arterial flow to the left lung. Right ventriculogram (C, frontal; D, lateral) demonstrates filling of the small, stenosed right pulmonary artery from the aorta. found at operation, and patching was required to assure adequate lumen size. In only 2 patients was it possible to obliterate the Waterston shunt by direct suturing from inside the aorta. In the patients in whom direct suturing of the shunt was not possible, the right pulmonary artery was mobilized proximal and distal to the site of the shunt; and as cardiopulmonary bypass was commenced, a partially occluding vascular clamp was placed on the aorta so as to occlude the shunt. The pulmonary artery was separated from the aorta by incising the aortic wall 1 to 2 mm. from the suture line. The aortic defect was repaired by direct suture. A small patch of pericardium was utilized to repair the residual 404 THE ANNALS OF THORACIC SURGERY

4 Obstruction After Aorta-to-Right Pulmonary Artery Shunt defect in the right pulmonary artery [14]. In 1 patient the patch was extended proximally from the site of narrowing in both the right and main pulmonary arteries across the anulus onto the right ventricular outflow tract. Patching of the pulmonary artery was required in all 14 patients whose shunts were constructed when they were under 1 year of age and in 2 of the 3 patients in whom the shunt was constructed between ages 1 and 4 years. Reconstruction of the pulmonary artery as described resulted in satisfactory hemodynamic results, and angiography has shown flow to both pulmonary arteries postoperatively (Fig. 3). In 1 patient the shunt had become occluded, resulting in complete blocking of the right pulmonary artery with the right lung supplied only by bronchial arteries. In this patient the right pulmonary artery was inadequate for reconstruction and was ligated. In all patients, resection of the infundibulum and closure of the ventricular septa1 defect were accomplished in the usual manner. Enlargement of the right ventricular outflow tract with a pericardial patch was necessary in 14 of the 16 patients who required patching of the right pulmonary artery and in 1 of the 2 patients not requiring a pulmonary artery patch. Comment Palliative procedures for infants with tetralogy of Fallot have been credited with increasing the size of the pulmonary vessels, improving the size of the left ventricle, and possibly retarding the development of bronchial collaterals [ 131. The subclavian-to-pulmonary artery anastomosis of Blalock and Taussig [S] has proved to be an excellent procedure when the child s anatomy permits its use. There are two reasons for the superiority of this procedure: the minimized risk of subsequent obstructive pulmonary vascular A FIG. 3. Frontal (A) and lateral (B) views of a postoperative right ventriculogram demonstrating normal-sized right and left pulmonary arteries. B VOL. 16, NO. 4, OCTOBER,

5 GAY AND EBERT disease [7] and the relative ease of management at the time of total intracardiac correction [15]. The small size of the subclavian artery jn the young infant often precludes its use in that age group, however, and therefore some alternative must be employed. Although anastomosing the descending aorta to the left main pulmonary artery as described by Potts and his associates [23] is an effective method of shunting, the technical difficulties [6, 10, 12, 181 imposed on subsequent intracardiac repair have led us to avoid this type of procedure whenever possible in the palliation of infants with tetralogy. The choice in most children under 6 months of age and in older children anatomically unsuitable for a Blalock-Taussig shunt has been the ascending aorta-to-right main pulmonary artery anastomosis first described by Waterston [31]. In our experience, total correction of tetralogy following this procedure has not been as simple as it was originally conceived to be [ll, 12, 181. In an earlier communication [14] 2 patients were reported in whom patching of the right pulmonary artery was required. It was believed initially that this represented an unusual situation; however, subsequent experience has led us to conclude that the necessity of repairing the right pulmonary artery following a Waterston shunt procedure represents the rule rather than the exception. Based on present data, this seems especially true if the shunt was constructed before the patient was 1 year old. In only 2 of the 18 patients in our series was it possible to close the shunt by simple suture from within the aorta; 1 patient had had her shunt done at age 4, and the other was 14 years old when the shunt was constructed. The development of obstructive pulmonary vascular disease was not seen in this group of patients. The complication has been reported by others in patients having aortopulmonary shunts of both the Waterston [17] and Potts [6, 101 type; but it is exceptionally rare following a subclavian-topulmonary artery shunt [7]. The size of the aortopulmonary anastomosis should not exceed 3 mm. in the neonate and 4 mm. in the older infant. A subclavian-to-pulmonary artery anastomosis is generally possible in children over 6 months in age. The occurrence of pulmonary edema following aortopulmonary shunting is not uncommon [5, 9, 171 and has been used by some as an indication that the shunt is too large and requires revision [17]. Those patients exhibiting symptoms of congestive failure following shunting are treated with digitalis and diuretics before consideration is given to surgically reducing the size of the shunt. The scarring and reaction seen at the time of total correction as well as kinking of the right pulmonary artery seem to limit expansion of the shunt and to some degree control the amount of flow. Subsequent reduction in lumen size, even with complete occlusion, was observed, probably due to angulation progressing with growth of the child. Others have noticed unequal distribution of blood flow following a 406 THE ANNALS OF THORACIC SURGERY

6 Obstruction After Aorta-to-Right Pulmonary Artery Shunt Waterston shunt procedure. In 3 of 6 patients reported by Garzon and associates [ 171 who underwent recatheterization one to four years following a Waterston procedure, marked inequalities in distribution of shunt and pulmonary arterial flow were demonstrated by aortogram and lung scans. Oldham and associates [22] called attention to the same phenomenon in an experimental study. Albers and Nadas [ 11 reported unilateral pulmonary edema in 3 patients following insertion of systemic-to-pulmonary artery shunts. Two of these patients had had Waterston procedures. Because total correction of tetralogy of Fallot is being performed at younger ages [3, 4, 19, 291, the need for palliative shunting will decrease. Unfortunately, the infant with the least favorable anatomy (such as small pulmonary anulus and diminutive pulmonary arteries) who presents with deep cyanosis or hypoxemia at birth or shortly thereafter is the least favorable candidate for early total correction. In all probability, these patients will remain candidates for a palliative operation, perhaps followed by extensive reconstruction of the right ventricular outlet [21, 251. In this situation the ascending aorta-to-right pulmonary artery shunt best answers the need for ease of performance, short operating time, best lumen size relative to the small size of the pulmonary artery, and success of take-down at the time of total correction. From the present report it seems proper to emphasize that a major effort should be made to place the anastomosis as far posterior on the aorta as possible to insure flow to both lungs and reduce the possibility of kinking of the right pulmonary artery. References 1. Albers, W. H., and Nadas, A. S. Unilateral chronic pulmonary edema and pleural effusion after systemic-pulmonary shunts for cyanotic congenital heart disease. Am. J. Cardiol. 19:861, Azzolina, G., Eufrate, S., and Pensa, P. M. Intrapericardial aortopulmonary anastomosis. Znt. Surg. 57:321, Barratt-Boyes, B. G. Cardiac surgery in neonates and infants. Circulation 44:924, Barratt-Boyes, B. G., Simpson, M. M., and Neutze, J. M. Intracardiac surgery in neonates and infants using deep hypothermia with surface cooling and limited cardiopulmonary bypass. Circulation 43 (Suppl. 1):I-25, Bernhard, W. F., Litwin, S. B., Williams, W. W., Jones, J. E., and Gross, R. E. Recent results of cardiovascular surgery in infants in the first year of life. Am. J. Surg. 123:451, von Bernuth, G., Ritter, D. G., Frye, R. L., Weidman, W. H., Davis, G. D., and McGoon, D. C. Evaluation of patients with tetralogy of Fallot and Potts anastomosis. Am. J. Cardiol. 27:259, von Bernuth, G., Ritter, D. G., Schattenburg, T. T., and DuShane, J. W. Severe pulmonary hypertension after Blalock-Taussig anastomosis in a patient with tetralogy of Fallot. Chest 58:380, Blalock, A., and Taussig, H. B. The surgical treatment of malformations of the heart in which there is pulmonary stenosis or pulmonary atresia. J.A.M.A. 128: 189, Bourland, B. J., and McNamara, D. G. Tetralogy of Fallot: Natural course,

7 GAY AND EBERT indications for surgery and results of surgical treatment. Cardiovasc. Clzn. 2: 196, Cole, R. B., Muster, A. J., Fixler, D. E., and Paul, M. H. Long term results of aortopulmonary anastomosis for tetralogy of Fallot: Mortality and morbidity Circulation 43:263, Cooley, D. A., and Hallman, G. L. Intrapericardial aortic-right pulmonary arterial anastomosis. Surg. Gynecol. Obstet. 122: 1084, Cooley, D. A., and Hallman, G. L. Surgical Treatment of Congenztal Heart Disease. Philadelphia: Lea & Febiger, P Ebert, P. A. Surgical treatment for tetralogy of Fallot: A quarter of a century of progress. Cardiovasc. Clin. 4:305, Ebert, P. A., Gay, W. A., Jr., and Oldham, H. N. Management of aorto-right pulmonary artery anastomosis during total correction of tetralogy of Fallot. Surgery 71:231, Ebert, P. A., and Sabiston, D. C., Jr. Surgical management of the tetralogy of Fallot: Influence of a previous systemic-pulmonary anastomosis on the results of open correction. Ann. Surg. 165:806, Engle, M. A. Medical management of the patient with congenital heart disease. Cardzovasc. Clzn. 2:268, Garzon, A. A., Goldstein, S., Ehrlich, R., Rodriguez-Torres, R., and Karlson, K. E. Technical and hemodynamic considerations of the Waterston shunt. J. Cardiovasc. Surg. (Torino) 13:240, Kirklin, J. W., and Karp, R. B. The Tetralogy of Fallot: From a Surgical Viewpoint. Philadelphia: Saunders, P Malm, J. R., Bowman, F. O., Jesse, M. J., and Blumenthal, S. Open heart surgery in the infant. Am. J. Surg. 119:613, McGoon, D. C. Surgical management of congenital heart disease: Viewpoint of the surgeon. Cardiovasc. Clin. 2:288, McGoon, D. C., Wallace, R. B., and Danielson, G. K. Homografts in reconstruction of congenital cardiac anomalies. Mayo Clin. Proc. 47: 101, Oldham, H. N., Jr., Simpson, L., Jones, R. H., Goodrich, J. K., and Sabiston, D. C., Jr. Differential distribution of pulmonary blood flow following aortopulmonary anastomosis. Surg. Forum 21 :201, Potts, W. J., Smith, S., and Gibson, S. Anastomosis of the aorta to a pulmonary artery. J.A.M.A. 132:627, Puga, F. J., DuShane, J. W., and McGoon, D. C. Treatment of tetralogy of Fallot in children less than four years of age. J. Thorac. Cardzovasc. Surg. 64:247, Rastelli, G. C., Titus, J. L., and McGoon, D. C. Homograft of ascending aorta and aortic valve as a right ventricular outflow. Arch. Surg. 95:698, Selmonosky, C. A., Farhangian, D., Folger, G. M., and Ellison, R. G. Palliative shunting operations in tetralogy of Fallot: Effects upon the results of total correction. Ann. Thorac. Surg. 14:16, Semb, G. S., and Hall, K. V. Aorto-pulmonary shunt in congenital cyanotic heart disease. Scand. J. Thorac. Cardiovasc. Surg. 6:43, Stark, J., Hucin, B., Aberdeen, E., and Waterston, D. J. Cardiac surgery in the first year of life: Experience with 1,049 operations. Surgery 69:483, Subramanian, S., Wagner, H., Vlad, P., and Lambert, E. Surface induced deep hypothermia in cardiac surgery. J. Pediatr. Surg. 6:612, Waldhausen, J. A., Friedman, S., Tyers, G. F. O., Rashkind, W. J., Petry, E. and Miller, W. W. Ascending aorta-right pulmonary artery anastomosis: Clinical experience with thirty-five patients with cyanotic congenital heart disease. Circulation 38:463, THE ANNALS OF THORACIC SURGERY

8 Obstruction After Aorta-to-Right Pulmonary Artery Shunt 31. Waterston, D. J. Treatment of Fallot s tetralogy in children under one year of age. Rozhl. Chir. 41: 181, Discussion DR. GORDON K. DANIELSON, JR. (Rochester, Minn.): I wish to commend the authors for emphasizing a problem that is being encountered with increasing frequency as early aorta-to-right pulmonary artery anastomoses are being closed during definitive repair of cyanotic cardiac defects. The occurrence of complete occlusion of the right pulmonary artery in about two-thirds of their patients is a somewhat higher incidence than most of us are encountering and raises questions about the technique of performing the anastomosis. It is probable, as the authors have emphasized, that proper rotation of the aorta before clamping it so that the subsequent anastomosis is directly posterior will prevent most of these occurrences. However, all this is academic when one is faced with a patient being considered for total correction who has a functioning aorta-to-right pulmonary artery anastomosis. Dr. Gay has suqgested that all these patients should undergo preoperative angiography to define the anatomy, and certainly this is a reasonable approach. We have usually relied on intraoperative assessment of the anatomy, measuring pressures in the main pulmonary artery and distal right pulmonary artery. If there is a significant discrepancy or if the anastomosis appears distorted, the right pulmonary artery is detached from the aorta the way one would handle a truncus (similar to the technique described by the authors), and the pulmonary artery is then reconstructed with a patch. If all looks satisfactory prior to bypass, the anastomosis is closed from within the aorta. Then, during repair of the right ventricular outflow tract, a long, curved clamp is inserted into both the right and left pulmonary arteries to ascertain their patency. This has occasionally allowed us to detect an unsuspected right pulmonary artery arising from the aorta or an atretic left pulmonary artery. Finally, it has been our practice at the conclusion of bypass and before decannulation to remeasure pressures in all cardiac chambers and the main right and left pulmonary arteries. If there is significant residual stenosis at either the right ventricular outflow tract or the site of the anastomosis closure, bypass is resumed and repair is carried out as indicated. This last step is important even if a preoperative angiogram has been obtained, as it is possible to narrow the right pulmonary artery by closure of the anastomosis even when no obstruction is apparent on the preoperative study. I would like to ask two short questions of Dr. Gay. Has he seen unilateral pulmonary arterial hypertension in his patients with obstructed right pulmonary arteries, and has his experience as reported here influenced his philosophy about the type of shunting to be performed in young children? DR. KEITH W. ASHCRAFT (Kansas City, Mo.): I would like to present a bit of the experience at Great Ormond Street, including Mr. Waterston s, on which we reported last year. In the series of 96 ascending aorta-to-right pulmonary artery shunts done at Great Ormond Street between 1960 and 1971, there were 61 patients with Fallot s tetralogy. Fifty of these patients survived to leave the hospital for various corners of England and even all parts of the world. There were 8 patients who had subsequent repair in London tlurino, the time of this study. Of these 8 patients, transaortic suture closure was carried out in 7. One patient was explored through the aorta and found to have an obliterated shunt. At operation we did not recognize any kinking of the pulmonary artery on the right side, nor in the postoperative period did we notice any untoward effects from this approach. VOL. 16, NO. 4, OCTOBER,

9 GAY AND EBERT We think perhaps this is accounted for by the approach that we uniformly use for constructing the shunt, that is, going behind the superior vena cava and approaching the aorta along this route. It allows a little more direct placement of the anastomosis on the back side of the aorta. I would like to ask the authors which approach they use: the one described by Mr. Waterston or the anterior approach promoted by others. PRESIDENT BENSON B. ROE: I would like to suggest that perhaps we shouldn t be too snobbish about our gynecological colleagues. The Hegar dilator is a very handy instrument for testing patency and establishing a lumen over which a patch can be placed to reconstitute the narrow lumen of a scarred pulmonary artery. DR. GAY: I agree with Dr. Danielson that postoperative measurement of pressures is an essential part of an operation for tetralogy of Fallot and would think that measurement of pressures prior to performing total correction would certainly be an adequate alternative to preoperative catheterization. In reply to his questions, we have not seen unilateral pulmonary artery hypertension in this group, although it has been described. We still do Waterston shunts in patients whose anatomy is unsuitable for a Blalock-Taussig shunt. In children whose anatomy is suitable, we prefer to do the latter type of anastomosis. In answer to Dr. Ashcraft s question, we have performed the ascending aortato-right pulmonary artery shunt in both manners-both anterior and posterior to the superior vena cava. It is worth mentioning that none of the 18 patients in this study had their shunts performed by either of the authors, so I really don t know exactly how all of them were done. We wish to thank Dr. Roe for his comments and agree with him that the Hegar dilator has many uses in cardiovascular surgery. 410 THE ANNALS OF THORACIC SURGERY