The first successful surgical repair of pulmonary artery

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1 Pulmonary Artery Sling: Results With Median Sternotomy, Cardiopulmonary Bypass, and Reimplantation Carl L. Backer, MD, Constantine Mavroudis, MD, Michael E. Dunham, MD, and Lauren D. Holinger, MD Department of Surgery, Northwestern University Medical School, Divisions of Cardiovascular-Thoracic Surgery and Otolaryngology, Children s Memorial Hospital, Chicago, Illinois Background. The classic surgical approach to pulmonary artery (PA) sling has been through a left thoracotomy with division of the left PA and reimplantation into the main PA anterior to the trachea. Another approach is anterior left PA translocation with distal. Since 1985, we have repaired PA sling with a median sternotomy approach, cardiopulmonary bypass, and division and reimplantation of the left PA into the main PA with simultaneous repair of associated tracheal stenosis. The purpose of this review is to determine the outcome of that strategy. Methods. From 1985 to 1998, 16 infants had surgical treatment of PA sling, 14 had left PA division and reimplantation into the MPA, 2 patients had repair using the translocation technique. Mean age at repair was 6.9 months, median age was 4 months. All infants, except 1 with an absent right lung, were operated on at the time of diagnosis. All had rigid bronchoscopy, which revealed associated complete tracheal rings in 12 patients. Seven patients had tracheal repair with pericardial tracheoplasty, 4 had repair using a tracheal autograft technique, and 2 had a distal (one for tracheomalacia). Of the 2 patients having the translocation technique, 1 had a severely hypoplastic right lung and the other had complete absence of the right lung. Results. There has been no operative mortality. Hospital stay ranged from 5 to 188 days (mean days). There was 1 late death 7 months postoperatively from respiratory complications of pericardial tracheoplasty. All left pulmonary arteries are patent and blood flow to the left lung by nuclear scan (n 10) ranges from 24% to 46% (mean 35% 9%). Conclusion. The strategy of median sternotomy, cardiopulmonary bypass, and left PA division and reimplantation into the main PA with simultaneous tracheal repair has resulted in a low operative mortality and excellent patency of the left pulmonary artery. Results with repair of the commonly associated complete tracheal rings has recently improved with the use of the free tracheal autograft technique. (Ann Thorac Surg 1999;67: ) 1999 by The Society of Thoracic Surgeons The first successful surgical repair of pulmonary artery (PA) sling was performed by Willis J. Potts at the Children s Memorial Hospital (CMH), Chicago in 1953 [1]. Potts divided the LPA and reanastomosed the 2 ends back together anterior to the trachea through a right thoracotomy. In 1975 Koopot updated the CMH experience with a total of 3 surgical patients; 1 was the patient reported by Potts, 1 was repaired through a median sternotomy (but without cardiopulmonary bypass), the third was repaired through a left thoracotomy [2]. We updated this experience again in 1992, with at that time a total of 12 patients; 3 previously reported, 5 repaired with a left thoracotomy approach and 4 repaired with a median sternotomy approach and the use of cardiopulmonary bypass [3]. This current review analyzes our Presented at the Thirty-Fifth Annual Meeting of The Society of Thoracic Surgeons, San Antonio, TX, January 24 27, Address reprint requests to Dr Backer, Division of Cardiovascular- Thoracic Surgery, Children s Memorial Hospital, m/c 22, 2300 Children s Plaza, Chicago, IL 60614; c-backer@nwu.edu. results with a total of 16 patients having repair through a median sternotomy approach with the use of cardiopulmonary bypass and having simultaneous repair of associated complete tracheal rings. Current areas of controversy in the management of pulmonary artery (PA) sling include surgical approach (median sternotomy versus left thoracotomy) [4], use or non-use of cardiopulmonary bypass, and reimplantation versus translocation with distal [5]. There has also been a variety of surgical approaches described for the commonly associated tracheal stenosis ( ring-sling complex ) [6] including [7], pericardial tracheoplasty [8], cartilage tracheoplasty [9], slide tracheoplasty [10], tracheal homograft [11], and tracheal autograft [12]. This review focuses on the results of surgical repair utilizing a median sternotomy, cardiopulmonary bypass, left pulmonary artery division and reimplantation into the main pulmonary artery, and simultaneous tracheal repair. In particular, we evaluated the surgical and late 1999 by The Society of Thoracic Surgeons /99/$20.00 Published by Elsevier Science Inc PII S (99)

2 Ann Thorac Surg BACKER ET AL 1999;67: PA SLING REPAIR WITH BYPASS 1739 Fig 1. PA sling patients: Children s Memorial Hospital, mortality, results of repair of associated tracheal stenosis, and long-term patency of the left pulmonary artery. Patients and Methods Between 1953 and 1998, 24 infants underwent surgical repair of a PA sling at CMH, Chicago. There were 14 males and 10 females. Age ranged from 8 days to 40 months (mean age months, median age 4 months). The frequency of surgical repair by 5 year intervals is demonstrated in Figure 1. One patient (the first) was approached through a right thoracotomy. Six patients were approached through a left thoracotomy ( ). Seventeen patients were repaired through a median sternotomy (1970, ), and of these, 16 were repaired with the use of cardiopulmonary bypass (CPB). Associated anomalies in the total series of 24 patients are shown in Table 1. This report focuses on the 16 patients repaired with CPB that had reimplantation of the LPA into the MPA (n 14) or PA translocation (n 2) with simultaneous repair of associated tracheal stenosis. Diagnosis Of the 16 patients that underwent repair using CPB, all had respiratory symptoms. These included wheezing, stridor, respiratory distress, and respiratory arrest. Seven of the 16 were transferred to CMH intubated and ventilated. Physical examination revealed stridor, rhonchi, secretions, wheezing, and episodes of desaturation. One patient had an episode of hemoptysis 36 hours after being intubated for respiratory distress. Diagnostic studies prior to operative repair are shown in Table 2. All children diagnosed with PA sling underwent rigid bronchoscopy either as their first diagnostic study (n 7), preoperatively after sling diagnosis (n 5), or intraoperatively just prior to sling repair (n 4) to rule out associated complete tracheal rings. The cardiac ECHO is now considered our diagnostic procedure of choice [13]. An example of a color Doppler ECHO of a patient with PA sling is shown in Figure 2. The intracardiac anatomy should also be assessed to rule out associated cardiac lesions. Surgical Technique The patient is positioned close to the head of the table so that pre-, intra-, and postoperative rigid bronchoscopy can be performed as indicated. Following bronchoscopy, the entire chest and neck are prepped and draped so that the incision may be carried up on the neck if required for the tracheal repair. All patients are given perioperative antibiotics, cefazolin for older children and oxacillin and gentamycin for infants. Median sternotomy is performed. Subtotal resection of the thymus is achieved to maximize exposure of the superior mediastinum. If necessary for the tracheal repair, pericardium is harvested and preserved in saline. Using electrocautery the aorta is dissected away from the right pulmonary artery (RPA) and the left pulmonary artery (LPA) is identified originating from the superior aspect of the RPA (Fig 3). The ligamentum (or ductus) arteriosus is dissected, doubly ligated, and divided. The recurrent laryngeal nerve is identified and preserved. The space between the aorta and SVC is dissected to expose the trachea in the patient with associated complete tracheal rings. In these patients the innominate artery and vein are also freed up and encircled with vessel loops for later retraction. If necessary the strap muscles are divided in the midline, and sometimes even the thyroid isthmus is divided to fully expose a stenotic trachea. The patient in the illustrations had complete tracheal rings involving the distal two-thirds of the trachea (Fig 3). The patient is systemically heparinized and cardiopulmonary bypass is initiated. This allows complete freedom of manipulation of the pulmonary arteries without desaturation or right ventricular distention. It also provides complete respiratory support for the tracheal repair. The child is cooled slowly to 32 C (rectal) and remains in normal sinus rhythm throughout the procedure. Using partial occlusion clamps, the LPA is transected from its origin on the RPA. The opening in the RPA is closed with interrupted 7-0 prolene sutures. This prevents pursestringing of the suture line, which might cause RPA stenosis (Fig 3). The LPA is carefully dissected away from the posterior trachea and anterior esophagus. In 2 patients the right upper lobe PA actually originated from the LPA. This necessitated a slightly more distal division of the LPA, allowing the right upper lobe to take off from a small residual stump of the LPA. The pericardium in the posterior mediastinum to the left of the ligamentum is opened. The LPA is identified anterior to the aorta and is pulled through the space posterior to the trachea into Table 1. Associated Anomalies in 24 Patients With Pulmonary Artery Sling ( ) Anomaly No. of Patients % Complete tracheal rings 14 58% Left superior vena cava 4 16% Patient ductus 4 16% arteriosus Tracheal right upper 2 8% lobe Ventricular septal defect 2 8% Hypoplastic right lung 2 8% Absent right lung 1 4%

3 1740 BACKER ET AL Ann Thorac Surg PA SLING REPAIR WITH BYPASS 1999;67: Table 2. Diagnostic Studies in 16 Patients With PA Sling ( ) Year Bronchoscopy as 1st Study Echocardiogram Pulmonary Angiogram Computed Tomogram Magnetic Resonance Imaging Barium Swallow 1985 X X 1990 X 1990 x 1991 X X X 1992 X X 1992 X X 1992 X X 1994 X 1994 X X X X 1994 X X 1996 X X X 1996 X X 1996 X X 1997 X X X 1998 X X 1998 X X Total the pericardium. The LPA is now lateral and anterior to the trachea. The site of implantation in the MPA is chosen to approximate the normal anatomic origin of the LPA. This usually corresponds to the site of the ligated ligamentum. The LPA is trimmed if necessary so that it is not so long as to want to kink. Sometimes we bevel the incision in the LPA to make a longer fish mouth anastomosis. The LPA is anastomosed to the opening created in the MPA with interrupted 7-0 prolene (n 11) (Ethicon, Inc, Somerville, NJ) or polydioxanone (PDS) (n 3) suture (Fig 2). When the vascular anastomosis is completed, attention is directed to the tracheal repair. In the current review of 16 patients repaired with median sternotomy and cardiopulmonary bypass since 1985, 7 underwent tracheal repair with a pericardial tracheoplasty, 4 using a tracheal autograft technique, and 2 underwent distal tracheal resection. Figure 4 illustrates the pericardial tracheoplasty technique. An opening is created in the trachea with a #11 blade anteriorly through the stenotic complete tracheal rings, and this opening is patched with autologous fresh pericardium anchored with interrupted 6-0 Vicryl sutures (Fig 4). The patch is then stented open with the endotracheal tube. More recently, we have used the tracheal autograft technique to repair the tracheal stenosis [11]. The mid portion of the stenotic trachea is excised as illustrated in Figure 5. The trachea is reapproximated posteriorly with Fig 2. Echocardiogram of PA sling. Color Doppler flow demonstrates a PA sling. The LPA originates from the RPA and encircles the distal trachea in its course to the left lung. MPA main pulmonary artery, LPA left pulmonary artery.

4 Ann Thorac Surg BACKER ET AL 1999;67: PA SLING REPAIR WITH BYPASS 1741 Fig 3. PA sling, LPA reimplantation. In patients with pulmonary artery sling, the LPA originates from the RPA and encircles the junction of the right main bronchus and the distal trachea. The LPA courses posterior to the trachea (anterior to the esophagus, not illustrated) on its way to the hilum of the left lung. The aorta is not shown. The ligated stump of the patent ductus arteriosus is illustrated on the left superior aspect of the MPA. The dotted lines indicate the opening to be created in the MPA for the reimplantation of the LPA. In the second panel, the origin of the LPA from the RPA has been transected and the RPA opening repaired primarily with interrupted 7-0 prolene suture. The LPA has been reimplanted into the MPA with interrupted 7-0 prolene sutures. The anticipated initial incision into the stenotic trachea is shown by the dotted line. interrupted 6-0 PDS suture. The corners of the autograft are trimmed and it is placed anteriorly as an onlay patch (Fig 6). The autograft is anchored in place with interrupted 6-0 PDS suture. Small hemoclips are placed to mark radiographically the superior and inferior aspect of the autograft. If the tracheal stenosis is too long to patch with the autograft, a small pericardial patch is used to augment the trachea superiorly. Cryoprecipitate glue is used to seal the tracheal anastomosis. The mediastinum is irrigated copiously with warm saline solution mixed with Amikacin. The sternotomy is closed in routine fashion. After either pericardial tracheoplasty or tracheal autograft, the postoperative respiratory regimen is quite important. The duration of postoperative intubation in the pericardial tracheoplasty patients was longer (usually 3 to 4 weeks) in order to stent the patch open as it healed and became adherent to the surrounding mediastinal structures. In the tracheal autograft patients, mean time to extubation was one to two weeks, enough time to allow the child to recover from the surgery and be strong enough to maintain their ventilation and cough. In the first week after surgery the peak airway pressures are kept under 35 mm Hg to prevent patch dehiscence. Suctioning is done every 2 to 4 hours, with the catheter gently advanced until it meets gentle resistance. PEEP is usually kept at 5 to 8 mm Hg. Prophylactic antibiotics are continued until the chest tubes are removed. All patients underwent elective bronchoscopy to evaluate the tracheal repair prior to extubation. Figure 7 illustrates a postoperative bronchoscopy of a 2-year-old boy that had a PA sling repair and tracheal autograft at 10 days of age. During the time period of the current study ( ), 2 patients had repair of their PA sling using the translocation technique. One patient had a severely hypoplastic right lung (23% of the flow by perfusion scan), and had translocation of the LPA anterior to the trachea during a tracheal autograft repair. The RPA measured only 3 mm in diameter as compared to a 10 mm LPA. This child also had dextrocardia. The other child had an absent right lung with no right bronchus or right PA, and underwent pulmonary artery translocation anterior to the trachea during a resection of her distal tracheal stenosis (2.0 cm resection). Another child had a resection of a distal area of severe tracheomalacia. The LPA was densely adherent to the posterior trachea and the trachea was entered during the PA dissection. A short segment of Fig 4. Pericardial tracheoplasty. The trachea has been opened anteriorly through the area of the complete tracheal rings. The patient is still being supported with CPB. The trachea is patched open with autologous fresh pericardium anchored with interrupted 6-0 Vicryl sutures. Fig 5. Tracheal autograft. The trachea has been opened anteriorly through the area of the complete tracheal rings. The mid-portion of the stenotic trachea (usually 6 8 rings, cm) is resected to be used later as the autograft.

5 1742 BACKER ET AL Ann Thorac Surg PA SLING REPAIR WITH BYPASS 1999;67: Fig 6. Tracheal autograft. After the trachea is anastomosed posteriorly, the autograft patch is trimmed as shown and inserted anteriorly to augment the tracheal lumen. distal trachea was excised and an end-to-end anastomosis was performed with interrupted PDS suture. Results There was no operative mortality. There was 1 late death, the first patient repaired with median sternotomy and CPB. That child died of airway complications of pericardial tracheoplasty 7 months postoperatively. Hospital stay ranged from 5 days to 188 days (mean days). Postoperative hospital stay in the patients having pericardial patch tracheoplasty ranged from days (mean days), versus days (mean days) for those having tracheal repair with the autograft technique (p 0.36, two-tailed student s t-test). Most of this time difference is reflected in the time to extubation. Follow-up is complete in all patients and ranges from 2 months to 9 years, (mean years). No patient required reoperation for bleeding and there were no significant complications related to the use of CPB. Of the 7 patients having pericardial patch tracheoplasty, 3 required surgical revision [14]. Two had later insertion of a cartilage graft in the distal trachea, and 1 had revision with a pericardial patch, all revisions performed through a sternotomy with CPB. One of the patients having an autograft with pericardial augmentation had recurrent tracheal stenosis develop in the portion of the trachea patched with pericardium. She required a temporary wire expandable Palmaz (Johnson & Johnson Interventional Systems Co, Warren, NJ) stent [15] and a permanent tracheostomy. Both patients having a distal tracheal resection had relatively smooth postoperative courses and were discharged at 8 and 36 days post-op. Postoperative pulmonary perfusion scans were performed in 10 patients. Percent of flow to the left lung ranged from 24% to 46% (mean 35% 9%). In the 2 patients with hypoplastic right lungs, the percent of flow to the left lung was 64% (reimplantation technique) and 77% (translocation technique). Early in this series, post-op LPA patency was documented by MRI scan in 3 patients, and by CT scan in 1 patient. Thus, in all surviving patients the LPA was documented to be patent. Comment Since 1985, we have repaired all patients with PA sling using a median sternotomy approach, cardiopulmonary bypass, and in 14 of 16 cases LPA division and reimplantation. Simultaneous repair of complete tracheal rings was performed in 12 patients. Two patients had LPA repair using the translocation technique; one had a severely hypoplastic right lung and the other absence of the right lung. This approach has been associated with no operative mortality, a 7% late mortality, and a patent LPA in all surviving patients. Three patients required reoperation for recurrent tracheal stenosis, and 1 patient required a tracheostomy. We strongly feel that all patients with PA sling should be repaired at the time of diagnosis. This has been our policy in all of the patients in this series with the exception being the child with absence of the right lung where the indication for surgery was progressive tracheal stenosis. Gikonyo and colleagues reported a mortality rate of 90% in patients that had a PA sling managed medically [16]. The diagnosis should be suspected in any child that has respiratory difficulties. The classic chest roentgenogram appearance is of a hyperinflated right lung. Although CT and MRI will demonstrate a PA sling, we currently use cardiac ECHO as the diagnostic procedure of choice [13]. The ECHO may be performed at the bedside and is easily available. In particular, the use of color flow Doppler allows precise mapping of the LPA around the distal trachea obviating the need for a cardiac catheterization. ECHO has been diagnostic in 10 of 10 patients since Only 2 patients have had a pulmonary angiogram since The last was in 1991 and in fact was interpreted as normal, leading to the child s transfer to our institution. Only 3 patients had a barium swallow and the last one was performed in All patients diagnosed with PA sling should undergo bronchoscopy by an experienced pediatric otolaryngologist to rule out associated congenital complete tracheal rings, present in 58% of our total series of patients with PA sling. In 7 of 16 patients in this series, the child s initial diagnostic study was bronchoscopy. It was only after the diagnosis of complete tracheal rings had been made that the diagnosis of PA sling was entertained. The approach through a median sternotomy has many advantages [4]. It allows the easy application of CPB in a child that has arterial oxygen desaturation. The PA sling anatomically originates from the RPA, which is at some distance when approached via left thoracotomy. The anastomosis to the LPA can be done in a deliberate, unhurried fashion with excellent exposure by retracting the PA and cardiac structures. This may help explain our 100% patency rate, and excellent percentage of perfusion to the left lung postoperatively (mean 35%). Another reason to use CPB is to facilitate the tracheal repair in infants with associated tracheal stenosis. Of note in our series, no patient required reoperation for bleeding and there were no other significant complications related to the use of CPB. We initially repaired the associated tracheal stenosis

6 Ann Thorac Surg BACKER ET AL 1999;67: PA SLING REPAIR WITH BYPASS 1743 Fig 7. Bronchoscopy 2 years post-op of a child that had PA sling repair with reimplantation and tracheal autograft repair of complete tracheal rings at age 10 days. The rings extended from cricoid to carina. with a pericardial patch tracheoplasty [8]. The difficulty with this approach was the postoperative granulation tissue and patch tracheomalacia. This is reflected in the prolonged hospital stay (56 days), high reoperation rate (3 of 7 patients), and, indeed accounted for our only late death. The tracheal autograft technique described has worked extremely well in 3 of 4 patients with a mean hospital stay of 26 days. One patient required a stent and a tracheostomy, with the complications related to the pericardial portion of the repair. The 2 patients that had resection of a limited segment of distal trachea did very well. Other surgeons have reported good results with pericardium [17] and with rib cartilage graft for the tracheal repair [18]. Jacobs recently reported the successful application of cryopreserved tracheal homograft for infants with recurrent tracheal stenosis after repair of complete tracheal rings and PA sling [11]. A summary of the literature regarding simultaneous repair of the ring/ sling complex is shown in Table 3. Although we have used the translocation technique described by Jonas successfully in 2 patients, we prefer the reimplantation technique. Of the 2 patients in which we used the translocation technique, 1 had an absent right lung and no RPA, the other had a very diminutive RPA. We have 2 concerns with the translocation technique. First, the anomalous distal takeoff of the LPA is left intact and the LPA, when placed anterior to the trachea, has a takeoff angle of nearly 180, and that may cause proximal LPA kinking. We believe this phenomenon occurred in the first patient reported by Potts, where the LPA was reimplanted at the site it was transected from on the RPA. That patient survived, but on late follow-up 24 years later has an occluded LPA [23]. In addition there is now the risk of anterior compression of the trachea by the LPA as it courses from its anomalous origin on the RPA to the left lung hilum. Infants with PA sling should be repaired at the time of diagnosis. Cardiac ECHO is our current diagnostic procedure of choice, as it is rapid and noninvasive. All infants should have bronchoscopy to rule out tracheal stenosis secondary to congenital complete tracheal rings. Table 3. Reports of Simultaneous PA Sling and Tracheal Stenosis Repair Author Year Patients Technique Hickey [7] LPA reimplantation, Jonas [5] LPA translocation, Yamaguchi [9] LPA reimplantation, cartilage graft Kessler [19] LPA reimplantation, Pawade [20] LPA translocation, Muraji [21] LPA reimplantation, slide tracheoplasty Heinemann [22] LPA reimplantation, Backer, current report (7) LPA reimplantation, pericardial tracheoplasty (3) LPA reimplantation, autograft (1) LPA reimplantation, a (1) LPA translocation, autograft (1) LPA translocation, a Resection performed for tracheomalacia LPA Left pulmonary artery.

7 1744 BACKER ET AL Ann Thorac Surg PA SLING REPAIR WITH BYPASS 1999;67: Repair using a strategy of median sternotomy, CPB, LPA division and reimplantation into the MPA, and simultaneous tracheal repair has resulted in a low operative mortality and excellent patency of the LPA. Our tracheal repair results have recently improved with the use of the tracheal autograft technique. References 1. Potts WJ, Holinger PH, Rosenblum AH. Anomalous left pulmonary artery causing obstruction to right main bronchus: report of a case. JAMA 1954;155: Koopot R, Nikaidoh H, Idriss FS. Surgical management of anomalous left pulmonary artery causing tracheobronchial obstruction: pulmonary artery sling. J Thorac Cardiovasc Surg 1975;69: Backer CL, Idriss FS, Holinger LD, et al. Pulmonary artery sling. Results of surgical repair in infancy. J Thorac Cardiovasc Surg 1992;103: Campbell DN, Clarke DR, Lilly JR. Pulmonary artery sling [Letter]. J Thorac Cardiovasc Surg 1990;99: Jonas RA, Spevak PJ, McGill T, Castaneda AR. Pulmonary artery sling: primary repair by in infancy. J Thorac Cardiovasc Surg 1989;97: Berdon WE, Baker DH, Wung JT, et al. Complete cartilagering tracheal stenosis associated with anomalous left pulmonary artery: the ring-sling complex. Radiology 1984;152: Hickey MJ, Wood AE. Pulmonary artery sling with tracheal stenosis: one-stage repair. Ann Thorac Surg 1987;44: Idriss FS, DeLeon SY, Ilbawi MN, et al. Tracheoplasty with pericardial patch for extensive tracheal stenosis in infants and children. J Thorac Cardiovasc Surg 1984;88: Yamaguchi M, Oshima Y, Hosokawa Y, et al. Concomitant repair of congenial tracheal stenosis and complex cardiac anomaly in small children. J Thorac Cardiovasc Surg 1990; 100: Grillo HC. Slide tracheoplasty for long-segment congenital tracheal stenosis. Ann Thorac Surg 1994;58: Jacobs JP, Elliott MJ, Haw MP, Bailey CM, Herberhold C. Pediatric tracheal homograft reconstruction: a novel approach to complex tracheal stenoses in children. J Thorac Cardiovasc Surg 1996;112: Backer CL, Mavroudis C, Dunham ME, Holinger LD. Repair of congenital tracheal stenosis with a free tracheal autograft. J Thorac Cardiovasc Surg 1998;115: Alboliras ET, Backer CL, Holinger LD, Mavroudis C. Pulmonary artery sling diagnostic and management strategy. Pediatrics 1996;98(suppl II): Backer CL, Mavroudis C, Dunham ME, et al. Reoperation after pericardial patch tracheoplasty. J Pediatr Surg 1997;32: Furman RH, Backer CL, Dunham ME, Donaldson J, Mavroudis C, Holinger LD. The use of balloon-expandable metallic stents in the treatment of pediatric tracheomalacia and bronchomalacia. Arch Otolaryngol Head Neck Surg 1999; 125: Gikonyo BM, Jue KL, Edwards JE. Pulmonary vascular sling: report of 7 cases and review of the literature. Pediatr Cardiol 1989;10: Bando K, Turrentine MW, Sun K, et al. Anterior pericardial tracheoplasty for congenital tracheal stenosis: intermediate to long-term outcomes. Ann Thorac Surg 1996;62: Jaquiss RDB, Lusk RP, Spray TL, Huddleston CB. Repair of long-segment tracheal stenosis in infancy. J Thorac Cardiovasc Surg 1995;110: Kessler RM, Wernly JA, Katz RW, Berman W. Pulmonary artery sling with severe tracheobronchial stenosis: repair in infancy by and pulmonary artery reimplantation. J Card Surg 1992;7: Pawade A, de Leval MR, Elliott MJ, Stark J. Pulmonary artery sling. Ann Thorac Surg 1992;54: Muraji T, Satoh S. Tsugawa C, et. al. Slide tracheoplasty: a case report of successful concomitant reconstruction of extensive congenital tracheal stenosis and pulmonary artery sling. J Pediatr Surg 1998;33: Heinemann MK, Ziemer G, Sieverding L, Baden W, Kaulitz R, Luhmer I. Long-segment in infancy utilizing extracorporeal circulation. In: Imai Y, Momma K, eds Proceedings of the 2nd World Congress of Pediatric Cardiology and Cardiac Surgery. New York: Futura Publishing, 1998, pp Campbell CD, Wernly JA, Koltip PC, Vitullo D, Replogle RL. Aberrant left pulmonary artery (pulmonary artery sling): successful repair and 24-year follow-up report. Am J Cardiol 1980;45: DISCUSSION DR MARK W. TURRENTINE (Indianapolis, IN): First, I would like to thank Dr Backer for supplying a copy of their paper for me to review. Dr Backer and his colleagues present an update to their 1992 report regarding an unusual and complicated problem. Their series now totals 24 patients, 16 undergoing repair with the use of median sternotomy and cardiopulmonary bypass. This, to my knowledge, is the largest single institutional experience with PA sling repair and, as such, remains one of the definitive papers regarding this entity. As noted by Dr Backer, the use of median sternotomy with bypass has become their standard approach in repairing this defect. Our experience over the past 20 years has yielded approximately 10 such patients and, with one exception, we have followed the same approach. We too have found relocating the left PA to the main PA a reliable technique, yielding excellent patency and growth. Two significant issues are related to this diagnosis: One is that 50% to 60% of patients will have associated tracheal stenosis secondary to complete cartilaginous rings. The other is that there is a high incidence of associated cardiac anomalies, ranging from simple left SVC to TOF/pulmonary atresia to single ventricle variants. Since a significant number of patients can present symptomatically at birth or shortly thereafter, there are several issues leading me to ask two questions. One, the paper is somewhat unclear. Do you address the associated cardiac anomalies at the time of your PA sling repair or do you stage those procedures? And two, with regard to the tracheal autograft, how long a segment or how many rings can you resect without pericardial augmentation, and do you feel that for the very long segment tracheal stenosis there is a distinct advantage to this composite repair compared to the pericardial tracheoplasty? And in addition, for shorter stenotic areas, is there an advantage of the autograft technique over a sliding tracheoplasty technique? This is an excellent report of your experience, and you and Dr Mavroudis are to be congratulated on the results. I would like to thank the Society for the privilege of discussing this paper. Thank you by The Society of Thoracic Surgeons /99/$20.00 Published by Elsevier Science Inc PII S (99)