Ann Thorac Surg 2007;84:1312-1315
© 2007 The Society of Thoracic Surgeons
Original Articles: Cardiovascular
Experience With Bovine Pericardium for the Reconstruction of the Aortic Arch in Patients Undergoing a Norwood Procedure
Victor O. Morell, MD*,
Peter A. Wearden, MD, PhD
Section of Pediatric Cardiothoracic Surgery of the Heart, Lung and Esophageal Surgical Institute, University of Pittsburgh Medical School, Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania
Accepted for publication May 11, 2007.
* Address correspondence to Dr Morell, Children’s Hospital of Pittsburgh, University of Pittsburgh, Room 2820, 3705 Fifth Ave, Pittsburgh, PA 15213 (Email: victor.morell{at}chp.edu).
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Abstract
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Background: The incidence of recurrent aortic arch obstruction after the Norwood procedure is between 0% and 36%. Allograft material is frequently used to enlarge the aorta; its use has been associated with the development of significant allosensitization. We report our experience using bovine pericardium for the reconstruction of the aortic arch in patients undergoing a Norwood procedure.
Methods: A retrospective analysis of 33 consecutive patients evaluated for a second-stage procedure after an initial Norwood repair was performed. All patients underwent a cardiac catheterization. The presence of recurrent arch obstruction (gradient > 10 mm Hg) and its management were noted. Three consecutive patients were tested for anti-HLA antibodies at the time of their Fontan procedure.
Results: The mean age at the time of the cardiac catheterization was 4.12 months (range, 2 to 7 months). The incidence of recurrent arch obstruction was 18.2% (6 patients). Four patients (12.1%) had distal obstruction, 1 patient (3%) had proximal obstruction, and 1 patient (3%) had mid-transverse arch obstruction. Five of the 6 patients underwent aortic arch reintervention consisting of four balloon dilatations and two surgical patch aortoplasties. Thirty-one patients advanced to a second-stage procedure, including 30 bidirectional Glenn anastomoses, and 1 Rastelli repair. No significant allosensitization was present in the patients tested.
Conclusions: The use of bovine pericardium in the Norwood procedure is associated with an acceptable incidence of recurrent arch obstruction. Its availability, lower cost, and possible immunologic advantages make it an attractive alternative to allograft material.
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Introduction
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The Norwood procedure was first introduced in 1980 [1] for the surgical management of patients with the then lethal condition known as hypoplastic left heart syndrome (HLHS). In the ensuing years this procedure has undergone multiple modifications intended to simplify the operative technique and to improve the surgical results, but despite its evolution, it continues to have a significant incidence of morbidity and mortality.
Recurrent aortic arch obstruction is a frequently observed complication of the Norwood procedure. Its incidence has been reported to be anywhere from 0% to as high as 36% [2–7]. Different surgical techniques for arch reconstruction, including patch aortoplasty and the use of only autologous tissue, have been shown to have a similar incidence of recurrent obstruction in this patient population. We are reporting our experience using a bovine pericardial patch for the reconstruction of the aortic arch in patients undergoing a Norwood procedure.
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Patients and Methods
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The study was approved by the University of Pittsburgh Medical Center, Children’s Hospital of Pittsburgh Institutional Review Board, and they waived the need for parental consent. This is a retrospective analysis of a single surgeon’s experience with the Norwood procedure using a bovine pericardial patch (Fig 1; Shelhigh, Inc, Millburn, NJ) for the aortic arch reconstruction. Since April 2002, 33 consecutive patients were evaluated for a second-stage procedure after undergoing an initial Norwood repair; all patients underwent a cardiac catheterization to assess their hemodynamics. Recurrent arch obstruction was defined as an arch gradient greater than 10 mm Hg. The original diagnosis, age at the time of cardiac catheterization, the presence and location of recurrent aortic arch obstruction, the surgical or medical management of the arch obstruction, and the second-stage procedure were noted from the patient’s medical records.
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Fig 1. Bovine pericardial aortic patch. Note the curvilinear shape of the patch, which facilitates the reconstruction of the aortic arch during the Norwood procedure.
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The presence of anti-human leukocyte antigen (HLA) antibodies in 3 consecutive patients at the time of their Fontan procedure was measured using a standard panel-reactive antibody screen and an enzyme-linked immunosorbent assay specific for immunoglobulin G anti-HLA antibodies against HLA class I and II antigens.
The Norwood procedure was performed under circulatory arrest. After transection of the pulmonary trunk, an aortotomy was extended from the level of the aortic valve sinuses, in the proximal ascending aorta, to the level of the descending thoracic aorta, well past the area of insertion of ductal tissue. The ductal tissue was not resected from the posterior aspect of the aorta. The pulmonary trunk was sutured to the proximal ascending aorta in a side-to-side fashion. A gusset of bovine pericardium was then used to augment the aortic arch. The augmentation was begun distally in the thoracic aorta, and continued proximally to the aortic arch. The proximal aspect of the pericardial gusset was then sutured to the transected proximal pulmonary trunk. All the anastomoses were performed with a 7-0 Prolene (Ethicon, Somerville, NJ) suture in a running fashion.
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Results
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The cardiac lesions included hypoplastic left heart syndrome (n = 30), unbalanced atrioventricular canal defect with aortic atresia and arch hypoplasia (n = 1), aortic atresia with a ventricular septal defect and arch hypoplasia (n = 1), and a double inlet–double outlet left ventricle with a restrictive bulboventricular foramen and arch hypoplasia (n = 1). The mean age at the time of evaluation for the second-stage procedure was 4.12 months (range, 2 to 7 months). Six patients (18.2%) were found to have recurrent arch obstruction (Table 1). The location of the area of obstruction in the aortic arch was as follows: at the level of the proximal anastomosis between the pulmonary trunk and the reconstructed aorta (n = 1), at the level of the transverse arch (n = 1), and at the level of the distal arch (n = 4). Thirty-one patients advanced to a second-stage procedure, including 30 cavopulmonary anastomoses (Glenn procedure) and one Rastelli repair. Two patients were found to have significant pulmonary artery hypoplasia and elevated pulmonary artery pressures and thus were not candidates for a second-stage procedure.
The management of the patients with recurrent distal aortic arch obstruction consisted of balloon dilatation; 1 patient required a left thoracotomy with a subclavian patch aortoplasty because of an unsuccessful dilatation. A prosthetic patch aortoplasty was performed in the patient with proximal arch obstruction. No intervention was performed in the patient with the transverse arch gradient; there was no discrete area of obstruction on the angiogram, and the gradient was considered mild (20 mm Hg).
The results of the panel-reactive antibody screen and enzyme-linked immunosorbent assay on the 3 patients tested (Table 2) demonstrated no signs of clinically significant alloantibody formation.
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Table 2 Results of the Panel-Reactive Antigen Screen and Enzyme-Linked Immunosorbent Assay in 3 Consecutive Patients at the Time of Their Fontan Procedure
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Comment
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In the initial description of the Norwood procedure [1], the reconstruction of the aortic arch was performed without the use of any prosthetic material. Subsequently, Pigott and associates [8] described a modification of the technique using an allograft patch to augment the ascending aorta and the transverse aortic arch. Both types of arch repair have been associated with an incidence of recurrent aortic arch obstruction.
In a recent publication, Griselli and associates [9] reported their extensive experience with the Norwood procedure and found a similar incidence of recurrent arch obstruction (14%) in patients with or without allograft patch augmentation of the aortic arch. Complete resection of the ductal tissue was not associated with a lower incidence of recurrent coarctation in their series. In our study, the use of bovine pericardium resulted in a similar incidence of recurrent arch obstruction (18.2%). The 2 patients with proximal and middle arch obstructions were operated on early in our experience, and we believe that technical issues (making the patch too small) played a significant role in their recurrence. Distal arch obstruction was most likely secondary to constriction of residual ductal tissue at the most distal aspect of the patch anastomosis.
There are several advantages to the use of bovine pericardium over allograft material for the aortic arch reconstruction in patients undergoing a Norwood procedure. The bovine pericardial patch is readily available and does not require any special storage (preserved in benzyl alcohol), unlike homograft tissue, which requires cryopreservation. Also, there are significant cost savings with the use of the bovine pericardium; the cost of the xenograft patch ($1,900) is less than a third that of the allograft patch ($7,295).
A very important issue that is frequently overlooked is the development of anti-HLA antibodies associated with the use of cryopreserved allograft material. Homograft tissue is well known to induce a response that involves both class I and class II anti-HLA antibodies [10]. In 2005, Meyer and colleagues [11] described the findings of a study comparing neonates undergoing a Norwood procedure using allograft material for the arch reconstruction versus neonates undergoing an arterial switch procedure with no exposure to allograft material. At 12 months after surgery the class I and class II panel-reactive antibody screens were 79% and 66% for the Norwood group, and 0% and 2% for the arterial switch group. They concluded that exposure to allograft material resulted in a profound donor-specific immunologic sensitization in the majority of patients. This level of anti-HLA antibody formation could negatively affect future transplantation.
An elevated panel-reactive antibody screen of greater than 10% has been independently associated with an increased risk of rejection and mortality in patients undergoing cardiac transplantation [12–16]. Jacobs and associates [12] reported their experience with pediatric cardiac transplantation in patients with elevated panel-reactive antibodies and found an increased incidence of early (25%) and overall (50%) mortality despite aggressive immunosuppression. In this study, all patients with significant anti-HLA antibody titers had undergone previous open heart surgery, and half of these procedures were hypoplastic left heart syndrome palliation.
The argument can be made that all patients undergoing a single-ventricle palliation will or could become transplant candidates in the future, thus allosensitization is an important consideration. We are currently evaluating, in a prospective study, the presence of anti-HLA antibodies in our Norwood patients with bovine pericardial patches. The 3 patients who were tested at the time of their Fontan, approximately 2 years after their initial Norwood procedure, demonstrated no signs of allosensitization (Table 2).
In our experience using the Shelhigh bovine pericardial patch, we have noticed a few differences in how it "handles" when compared with allograft tissue. The homograft material is more pliable and elastic, making it somewhat easier to work with. On the other hand, the pericardial patch does not dilate once pressurized, something that we have observed when using allograft material that could partially contribute to the branch pulmonary artery compression or stenosis frequently observed in these patients. Although slightly tougher (bovine pericardium), we have not encountered any difficulty in using fine sutures for the repair, and suture line bleeding has not been noted to be a problem. The curvilinear shape of the pericardial patch (Fig 1) is ideal for the reconstruction of the aortic arch, a major advantage over flat patches (autologous pericardium). From the medicolegal aspect, it is important to note that the U.S. Food and Drug Administration has approved the Shelhigh patch for aortic augmentation. Overall, our experience with the bovine pericardial patch has been positive.
In conclusion, the bovine pericardial patch is an acceptable bioprosthetic material for reconstruction of the aortic arch in patients undergoing a Norwood procedure and is associated with an acceptable incidence of recurrent arch obstruction. Its availability, lower cost, and possible immunologic advantages make it an attractive alternative to allograft material.
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Acknowledgments
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The authors wish to thank Janet Kreutzer, RN, MSN, and Ana Maria Manrique, MD, for their assistance in data collection.
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References
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- Norwood WI, Kirklin JK, Sanders SP. Hypoplastic left heart syndrome: experience with palliative surgery Am J Cardiol 1980;45:87-91.[Medline]
- Zellers TM. Balloon angioplasty for recurrent coarctation of the aorta in patients following staged palliation for hypoplastic left heart syndrome Am J Cardiol 1999;84:231-233.[Medline]
- Burkhart HM, Ashburn DA, Kostantinov IE, et al. Interdigitating arch reconstruction eliminates recurrent coarctation after Norwood procedure J Thorac Cardiovasc Surg 2005;130:61-65.[Abstract/Free Full Text]
- Tworetzky W, McElhinney DB, Burch GH, Teitel DF, Moore P. Balloon arterioplasty of recurrent coarctation after the modified Norwood procedure in infants Cathet Cardiovasc Interv 2000;50:54-58.[Medline]
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- Ishino K, Stumper O, De Giovanni JJ, et al. The modified Norwood procedure for hypoplastic left heart syndrome: early to intermediate results of 120 patients with particular reference to aortic arch repair J Thorac Cardiovasc Surg 1999;117:920-930.[Abstract/Free Full Text]
- Starnes VA, Griffin ML, Pitlick PT, et al. Current approach to hypoplastic left heart syndrome: palliation, transplantation, or both? J Thorac Cardiovasc Surg 1992;104:189-195.[Abstract]
- Pigott JD, Murphy JD, Barber GB, Norwood WI. Palliative reconstructive surgery for hypoplastic left heart syndrome Ann Thorac Surg 1988;45:122-128.[Abstract]
- Griselli M, McGuirk SP, Stumper O, et al. Influence of surgical strategies on outcome after the Norwood procedure J Thorac Cardiovasc Surg 2006;131:418-426.[Abstract/Free Full Text]
- Hooper DK, Hawkins JA, Fuller TC, et al. Panel-reactive antibodies late after allograft implantation in children Ann Thorac Surg 2005;79:641-645.[Abstract/Free Full Text]
- Meyer SR, Campbell PM, Rutledge JM, et al. Use of an allograft patch in repair of hypoplastic left heart syndrome may complicate future transplantation Eur J Cardiothorac Surg 2005;27:554-560.[Abstract/Free Full Text]
- Jacobs JP, Quintessenza JA, Boucek RJ, et al. Pediatric cardiac transplantation in children with high panel reactive antibody Ann Thorac Surg 2004;78:1703-1709.[Abstract/Free Full Text]
- Xydas S, Yang JK, Burke EM, et al. Utility of post-transplant anti-HLA antibody measurements in pediatric cardiac transplant recipients J Heart Lung Transplant 2005;24:1289-1296.[Medline]
- Pisani BA, Mullen GM, Malinowska K, et al. Plasmapheresis with intravenous immunoglobulin G is effective in patients with elevated panel reactive antibody prior to cardiac transplantation J Heart Lung Transplant 1999;18:701-706.[Medline]
- Singh G, Thompson M, Griffith B, et al. Histocompatibility in cardiac transplantation with particular reference to immunopathology of positive serologic crossmatch Clin Immunol Immunopathol 1983;28:56-66.[Medline]
- Loh E, Bergin JD, Couper GS, et al. Role of panel reactive antibody crossreactivity in predicting survival after orthotopic heart transplantation J Heart Lung Transplant 1994;13:194-201.[Medline]
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Abstract
Introduction
