Systemic-Pulmonary Shunts in Neonates and Infants Using Microporous Expanded Polytetrduoroethylene: Immediate and Late Results

Transcription

1 Systemic-Pulmonary Shunts in Neonates and Infants Using Microporous Expanded Polytetrduoroethylene: Immediate and Late Results James S. Donahoo, M.D., Timothy J. Gardner, M.D., Kenneth Zahka, M.D., and B. S. Langford Kidd, M.D. ABSTRACT Thirty infants with various types of cyanotic congenital heart disease underwent systemic-pulmonary artery shunts with a microporous polytetrafluoroethylene (PTFE) graft between May, 1976, and July, Sixteen of them were less than 1 month old, and the average age of the neonates was 5.3 days. There were no operative deaths and 5 hospital deaths, 2 related directly to the shunt. Five patients required early revision of the shunt. Relief from cyanosis was achieved in each patient. Twenty-five patients have been followed up to three and one-half years. There have been 2 late deaths and one late occlusion of the shunt. One patient outgrew the shunt and required secondary shunting procedures. Three of 30 patients have evidenced mild congestive heart failure, which has responded to digitalis. Because of the reliability and excellent late patency of the PTFE prosthesis, we consider it to be superior to a central or Potts shunt for relief from cyanosis in the neonate and infant, and as reliable as a Blalock-Taussig shunt. In recent years, there has been a trend to early repair of cyanotic congenital heart disease. However, there still remains a need for improving pulmonary blood flow by systemicpulmonary artery shunts in neonates and infants with complex congenital heart disease who are not favorable candidates for intracardiac repair. The standard systemic-pulmonary artery shunts, including the Blalock-Taussig, Potts, or Waterston anastomosis, have been used extensively and successfully in many infants with heart defects requiring increased From the Department of Surgery, Division of Cardiac Surgery, and the Department of Pediatrics, the Johns Hopkins University School of Medicine, Baltimore, MD. Presented at the Twenty-sixth Annual Meeting of the Southern Thoracic Surgical Association, Nov 1-3,1979, San Antonio, TX. Address reprint requests to Dr. Donahoo, Division of Cardiac Surgery, The Johns Hopkins Hospital, 601 N Broadway, Baltimore, MD pulmonary blood flow. Each of these shunts, however, has its limitations. The Potts and Waterston shunts have excellent records for reliability and patency. However, there have been reports of left ventricular failure and increased pulmonary vascular disease with their use [4, 8,91. Moreover, the Potts and Waterston shunts have proved to be difficult to take down at the time of intracardiac repair [2, 101. The Blalock-Taussig shunt is the most favored of the systemic-pulmonary artery shunt procedures, and its successful use has been reported in neonates [l, 111. Occasionally, however, because of technical or anatomical considerations, a Blalock-Taussig shunt cannot be constructed. In such patients a satisfactory substitute has been the use of expanded polytetrafluoroethylene (PTFE) grafts [3, 5, 71. This report describes our experience in 30 neonates and infants with a systemic-pulmonary artery shunt using a PTFE prosthesis. Material and Methods Between May, 1976, and July, 1979, 30 infants less than 2 years old underwent a systemicpulmonary artery shunt with a PTFE graft. Sixteen patients were less than 30 days old (average age, 5.3 days). All patients had complex cyanotic congenital heart disease and were markedly desaturated at the time of diagnosis. Arterial oxygen saturation averaged 62%. Diagnosis included the following: pulmonary atresia, 6 patients; tricuspid atresia, 8; tetralogy of Fallot, 8; transposition of the great arteries, 5; and pulmonary stenosis, 3 patients. Twenty patients had a descending aorta-pulmonary artery anastomosis; 6 patients had a subclavian or innominate artery-pulmonary artery anastomosis; and 5 patients had an ascending aorta-pulmonary artery anastomosis. Five millimeter shunts were used in 14 patients and 4 mm shunts in 16 patients by The Society of Thoracic Surgeons

2 147 Donahoo et al: PTFE Pulmonary Shunts in Infants All neonates with ductus-dependent lesions after cardiac catheterization and diagnosis were started on a regimen of prostaglandin El to assure ductal patency and lung perfusion. After the ph and arterial oxygen saturation stabilized, the patient underwent urgent operative intervention. The chest was opened on the side of the aortic arch. If a large innominate or subclavian artery was encountered, a PTFE shunt was constructed between this vessel and the ipsilateral pulmonary artery. If this vessel was judged to be inadequate in size, a descending aorta-ipsilateral pulmonary artery anastomosis was made. Sutures of 7-0 polypropylene were used for both proximal and distal anastomoses. An alpha-adrenergic stimulator was administered if blood pressure fell below 90 mm Hg, and heparin, 1 mg per kilogram of body weight, was given at the time of shunt construction. No further heparin was administered. In the postoperative period, blood pressure was kept at 90 mm Hg or more and, if necessary, adrenergic stimulators were administered. Results There were no intraoperative deaths. Five patients died during hospitalization, and the cause of death is described in the Table. Two of these deaths were attributed directly to the shunt procedure. One patient died of hypoxia resulting from a clotted shunt, and a second patient died of massive congestive heart failure after construction of an ascending aortapulmonary artery shunt. Five patients required early revision of the shunt, and in 3 of them the shunt had been placed in the central position from the aorta to the main pulmonary artery. At the time of shunt revision, a kinked shunt was responsible for these three shunt failures. Each patient surviving hospitalization had an improvement in arterial oxygen saturation. It was measured in each patient immediately after shunt procedures, but could not be compared with preoperative values because 14 of the neonates had been receiving prostaglandin prior to operation. This treatment had improved the arterial oxygen saturation initially. There is 10Oo/o follow-up of the 25 surviving patients from four months to three and one-half years. There have been 2 late deaths. One patient died of heart failure and was found at postmortem examination to have an incompetent atrioventricular valve. The second patient died of unknown causes. At postmortem examination, both patients were found to have patent shunts. One patient required a second shunting procedure fourteen months after the initial shunt because of a rising hematocrit, and 1 patient had a late occlusion of the shunt at six months and underwent intracardiac repair of the defect at that time. The remaining patients have maintained clinical stability. Hospital Deaths after Creation of a Polytetrafluoroethylene Systemic-Pulmonary Artery Shunt Patient No. Age Diagnosis Comments 1 8 mo Tricuspid atresia, hypoplastic right ventricle, pulmonary valve stenosis 2 Id Hypoplastic right ventricle, tricuspid atresia, pulmonary valve absent 3 Id Single ventricle, pulmonary valve stenosis, dextrocardia 4 7 wk Tricuspid atresia, pulmonary atresia 5 14 mo Pulmonary atresia PTFE aorta-mpa 4 mm shunt; shunt kinked and clotted and was revised successfully; severe hypoxia with brain death PTFE aorta-lpa 4 mm shunt; died of heart failure; shunt patent PTFE aorta-lpa shunt; died of pneumothorax; shunt patent PTFE aorta-mpa shunt; died of renal failure; shunt patent PTFE aorta-rpa shunt; died of congestive heart failure PTFE = polytetrafluoroethylene; MPA = main pulmonary artery; LPA = left pulmonary artery; RFA = right pulmonary artery.

3 148 The Annals of Thoracic Surgery Vol 30 No 2 August 1980 In all survivors, physical examination or postoperative catheterization has demonstrated shunt patency. Clinical status, auscultation, and hematocrit have been used to establish shunt patency in the 15 patients who have not undergone recatheterization. In each of these patients, the shunt has been judged to be patent on physical examination. Postoperative cardiac catheterization has been performed on 10 patients. In 9, shunt patency has been demonstrated. No specific complications have been related to the use of PTFE. There has been no evidence of aneurysm formation or shunt infection. Mild congestive heart failure occurred in 3 patients and was controlled easily with digitalis. In each of these patients there were complex congenital defects, and the congestive failure could not be definitely related to the shunting procedure. The position or size of the shunt in these 3 patients appeared to have no relation to the presence of congestive heart failure. There is no evidence of increased pulmonary vascular resistance in patients undergoing cardiac catheterization nor are there any physical findings of pulmonary hypertension in the patients being followed by clinical means alone. Comments In patients requiring systemic-pulmonary artery shunts for palliative relief from cyanotic congenital heart disease, the Blalock-Taussig shunt remains the preferable choice. This shunt has proved to be an effective method of relieving cyanosis with a low complication rate. The Waterston and Potts shunts devised to supplement the surgical armamentarium have proved to be problematical. The Potts shunt has a high incidence of congestive heart failure and pulmonary vascular changes, and the Waterston shunt also has been associated with a high incidence of congestive heart failure. In addition, the Waterston shunt frequently has been demonstrated to cause distortion of the pulmonary artery, which creates problems at the time of intracardiac repair, often requiring reconstruction of the pulmonary artery. While the Blalock-Taussig shunt is preferable, there are circumstances that occasionally make its use difficult or less than ideal. In small infants, the size of the subclavian artery may be inadequate to provide enough increase in pulmonary blood flow to sustain life. In patients with aberrant subclavian arteries, the shunt is less than adequate. In 1973, Matsumoto and colleagues [61 described the use of PTFE as an arterial substitute in dogs, and in 1976, Gazzaniga and associates [3] reported the use of PTFE for construction of aortopulmonary shunts. PTFE is an ideal vascular substitute for use in small infants and neonates. It is light, requires no preclotting, and has been demonstrated to have a porosity that allows tissue ingrowth and formation of a pseudointima. The material can be penetrated easily with a 7-0 needle, which is satisfactory for construction of arterial anastomoses in small arteries. Gazzaniga and co-workers [3] initially reported the use of PTFE shunts in a central position, that is, from the ascending aorta to the main pulmonary artery. In 5 of our patients, we used this central approach. It has the advantages of providing blood flow equally into both pulmonary arteries. In our experience, however, it sometimes can be difficult to obtain the proper length of the shunt, and three of the shunts failed because of a kinked graft. Subsequently, in the remaining 26 patients, we used a thoracic approach to construct the systemic-pulmonary artery shunts. In 20 we used the descending aorta-pulmonary artery interposition of the shunt (Fig 1). This is an easy technical procedure. It enables the surgeon to use a straight graft which is shorter than the length of graft used for a central approach because it does not require looping of the graft. This avoids the problem of kinking and also diminishes resistance within the conduit because of a reduced length. In 6 patients, a subclavian or innominate-pulmonary artery anastomosis was used (Fig 2). We believe this may be the procedure of choice if the subclavian or innominate artery is of sufficient size to allow the surgeon to technically perform an interposition PTFE shunt. Theoretically, the surgeon can utilize a 4 or 5 mm shunt with potential for the subclavian artery to increase in size as the child grows and thus to increase the flow through the shunt. Advantages to the use of PTFE in construct-

4 149 Donahoo et al: PTFE Pulmonary Shunts in Infants Irdsion - 4th. ifiz2ers;pzlce avian PTFE shunt Fig 1. Microporous expanded polytetrafluoroethylene (PTFE) prosthesis interposed between the descending thoracic aorta and the left pulmonary artery. Polypropylene 7-0 sutures are used for the anastomosis. L.pu1m.a. Vagus Aorta PTFE shunt Fig 2. Microporous expanded polytetrafluoroethy2ene (PTFE) prosthesis interposed between the left subclavian artery and the left pulmonary artery. ing a systemic-pulmonary artery shunt are several. A shunt with a consistent size can be constructed without regard to other anatomical considerations. We have found the use of 4 and 5 mm shunts to be adequate in infants and neonates. Late patency with this type of shunt procedure has been good, and there is a low incidence of kinking of pulmonary arteries. This should make the PTFE shunt easier to manage at the time of repair than the Waterston or Potts shunt. Placement of the PTFE shunt from the descending aorta or subclavian artery to the pulmonary artery rather than the use of a central type of PTFE shunt has provided good late patency in our patients and has avoided violation of the mediastinum, which may be advantageous when repair is necessary. The theoretical disadvantages to the use of foreign material have not been a problem in our patients or in other reported series. The ultimate patency of any new type of prosthetic device can be judged only when sufficient time

5 ~ ~~,I 150 The Annals of Thoracic Surgery Vol 30 No 2 August 1980 has elapsed. The follow-up on our patients has been relatively short. At the present time, the PTFE shunt should be considered for in- and neonates who require a systemicpulmonary artery shunt and in whom the Blalock-Taussig shunt is not anatomically feasible or has failed. The reliabilitv, excellent late patency, and relatively low incidence of serious complications make the PTFE systemicpulmonary artery shunt an attractive substitute. References 1. Chopra PS, Levy JM, Dacumos GC Jr, et al: The Blalock-Taussig operation: the procedure of choice in the hypoxic infant with tetralogy of Fallot. Ann Thorac Surg 22:235, Gay WA Jr, Ebert PA: Aorta-to-right pulmonary artery anastomosis causing obstruction of the right pulmonary artery: management during correction of tetralogy of Fallot. Ann Thorac Surg 16:402, Gazzaniga AB, Lamberti JJ, Siewers RD, et al: Arterial prosthesis of microporous expanded polytetrafluoroethylene for construction of aorta-pulmonary shunts. J Thorac Cardiovasc Surg 72:357, Greenwood RD, Nadas AS, Rosenthal A, et al: Ascending aorta-pulmonary artery anastomosis for cyanotic congenital heart disease. Am Heart J 94: Jennings RB Jr, Innes BJ, Brickman RD: Use of microporous expanded polytetrafluoroethylene grafts for aorta-pulmonary shunts in infants with complex cyanotic heart disease: a report of Seven cases. J Thorac Cardiovasc Surg - 76:489, Matsumoto H, Hasegawa T, Fuse K, et al: A new vascular prosthesis for a small caliber artery. Surgery 74:514, Miyamoto K, Zavanella C, Lewin AN, Subramanian S: Aorta-pulmonary artery shunts with expanded polytetrafluoroethylene (PTFE) tube. Ann Thorac Surg 27:413, Neches WH, Naifeh JG, Park SC, et al: Systemic-pulmonary artery anastomoses in infancy. J Thorac Cardiovasc Surg 70:921, Neufield EA, Woldman JD, Paul MH, et al: Pulmonary vascular disease after systemicpulmonary arterial shunt operations. Am J Cardiol 39:715, Stewart S, Harris P, Manning J: Current results with construction and interruption of the Waterston anastomosis. Ann Thorac Surg 25:431, Tyson KRT, Larrieu AJ, Kirchmer JT Jr: The Blalock-Taussig shunt in the first two years of life: a safe and effective procedure. Ann Thorac Surg 26:38, 1978 Notice from the Southern Thoracic Surgical Association The Twenty-seventh Annual Meeting of the Southern Thoracic Surgical Association will be held at the Greenbriar, White Sulphur Springs, WV, Nov 13-15, There will be a $100 registration fee for nonmember physicians except for guest speakers, authors and co-authors on the program, and residents. Applications for membership should be completed by Sept 1, 1980, and forwarded to E. P. Smith, Jr., M.D., 425 S Bath Club Blvd, N Redington Beach, FL Richard B. McElvein, M.D Secreta y-treasurer