J Thorac Cardiovasc Surg 2001;121:1222-1223
© 2001 The American Association for Thoracic Surgery
Extra-anatomic aortic bypass for thoracic aortic obstruction
Donald B. Doty, MD
Department of Surgery
LDS Hospital
324 Tenth Ave
Salt Lake City, UT 84103
To the Editor:
Kanter and colleagues are to be commended for providing a useful operative solution to a difficult problem: complex aortic arch stenosis in children. They proposed an extra-anatomic aortic bypass to route blood flow from the ascending aorta to the descending aorta with a Dacron graft. The graft was attached to the descending thoracic aorta after it was exposed through the posterior pericardium by retracting the heart superiorly. The graft was routed through the pericardial sac anterior to the inferior vena cava and along the right side of the right atrium to an anastomosis to the ascending aorta. Their group comprised 19 patients. Cardiopulmonary bypass was not used in 13 patients; of the 6 other patients, 5 had the operation performed on bypass during concomitant intracardiac operations. Results were excellent.
I have used a similar approach in adult patients. Patients with aortic valve disease caused by a bicuspid valve often have associated coarctation of the aorta. The coarctation has usually been repaired previously, but there may be residual stenosis of the aorta that requires attention. Patients with previously repaired coarctation may present as adults with other intracardiac lesions (especially atrial septal defect) and are found to have incompletely relieved thoracic aortic obstruction. I have thought it optimal to repair residual aortic problems at the time of intracardiac operations by extra-anatomic aortic bypass and have performed this combined procedure on several occasions. I offer some suggestions that may improve the operation as described by Kanter and colleagues.
Exposure of the descending thoracic aorta through the posterior pericardium is easy with the heart arrested and decompressed on cardiopulmonary bypass. The heart is retracted superiorly for easy access to the aorta behind the pericardial sac. The aortic dissection may be accomplished quickly and an end-to-side anastomosis of graft to aorta performed quite easily. I have preferred to use an externally reinforced polytetrafluoroethylene graft to avoid graft compression by the heart or surrounding structures. A bypass graft larger than 10 or 12 mm is not required for treatment of mild or moderate stenosis of the aorta according to our knowledge of graft diameter required for aortic bypass with axillo-femoral extra-anatomic grafts. The shortest route to the ascending aorta and the one least likely to compress the graft is posterior to the inferior vena cava (Fig 1). The inset in the figure shows the location of the great vessels as they penetrate the pericardial sac. There is a nice passageway (arrow) behind the cava that is opened by incision of the pericardial reflection between the inferior vena cava and the right inferior pulmonary vein. The inferior vena cava is less vulnerable to compression by the bypass graft being placed posterior to it. The route to the right of the right atrium for anastomosis to the ascending aorta places the graft well posterior in the pericardial sac and protects it from injury should re-entry sternotomy be required at a later time.
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Fig. 1. Ascending aorta–descending thoracic aorta bypass for coarctation of the aorta with intracardiac defects. The inset shows the great vessels as they penetrate the pericardial sac. The route of the graft is shown by the arrow. An opening in the posterior pericardial sac exposes the aorta. An externally reinforced polytetrafluoroethylene graft is anastomosed end to side of the descending thoracic aorta. The pericardial reflection is opened between the right inferior pulmonary vein and the inferior vena cava providing a passageway posterior to the cava. The graft is routed inside the pericardial sac to the right side of the right atrium. An end-to-side anastomosis of the graft to the ascending aorta is constructed. Ao, Aorta; IVC, inferior vena cava.
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12/8/114773doi:10.1067/mtc.2001.114773
Reference
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Kanter KR, Erez E, Williams WH, Tam VKH. Extra-anatomic aortic bypass via sternotomy for complex aortic arch stenosis. J Thorac Cardiovasc Surg 2000;120:885-90.[Abstract/Free Full Text]
