Descending Thoracic Aorta to Femoral Bypass



Descending Thoracic Aorta to Femoral Bypass



Peter Hunt and Walter J. McCarthy


The descending thoracic aorta–to–femoral artery bypass can be defined as a bypass from the aorta just proximal to the diaphragmatic hiatus with either a bifurcated or tube graft reaching the iliac or femoral arterial system. This operation was first performed in 1956 by Sauvage, who used an aortic homograft for a patient who had standard aortoiliac graft failure. In 1961, Blaisdell used the thoracofemoral bypass for reconstruction after removing an infected infrarenal aortic prosthesis. Increasing acceptance of this operation by the surgical community is reflected by reports of 166 similar cases in the literature by the early 1990s and many more since.



Indications


This operation is simple in concept but should be restricted to very special settings in which conventional arterial grafting configurations are inadequate. As a general rule, if simpler or more commonly used operations can achieve the same end, they should be used in preference to the thoracofemoral bypass. Thus, although the thoracic aorta provides excellent inflow for treatment of an infrarenal aortic occlusion, the routine intraabdominal approach remains preferred. Although the thoracofemoral operation has been described for situations of acute aortic infection, one might more reasonably use an axillofemoral bypass instead. The reason is that in the septic patient, if the extra-anatomic repair were to become infected, the axillary-based graft is easier to manage than one anastomosed to the descending thoracic aorta. Therefore, in the relatively common setting of infected infrarenal aortic bypass removal, an axillofemoral bypass is still recommended.


Three specific indications have evolved. The first indication is the rare situation of a hostile abdomen, usually after either extensive previous operations or radiation in the periaortic region. Circumstances including inflammatory bowel disease or abdominal wall deficiencies can enter into this decision. In such patients, aortic inflow from the left chest may be less traumatic than an abdominal exploration. The second indication is for repeated failure of abdominal aortic grafting. As a general rule, failure after a single aortofemoral bypass is appropriately managed with another intraabdominal aortic graft. After two failures, one may reasonably consider moving to the thoracic aorta for inflow. Finally, the thoracofemoral bypass has been useful for patients with multiple failed extra-anatomic bypasses. They include patients with axillopopliteal and axillofemoral grafts having had multiple graft thrombectomy operations. Many of these patients were first seen at the time of infected aortic graft removal, and reconstruction was performed in the usual way with axillary-based inflow grafts. Following removal of their infected grafts, many such patients enjoy a potentially long life and are gravely affected by their repeated axillary graft thromboses. A reconstruction providing an uninhibited inflow source such as the descending thoracic aorta and the intracavitary tunnel of the thoracofemoral bypass seems reasonable in this setting.



Surgical Technique


The patient is positioned to maintain adequate surgical access to both femoral arteries. The pelvis is left reasonably flat, with a rotation of the thorax to about 30 degrees (Figure 1). A thoracotomy incision is made in the sixth or seventh intercostal space and brought across the costal cartilage for several centimeters onto the abdominal wall. Remove 1 or 2 centimeters of costal cartilage with the curved Mayo scissors for a less painful closure. After the thoracic cavity is entered, the diaphragm is incised for several centimeters in a radial fashion. Later, the bypass graft will pass through this short incision.


Stay updated, free articles. Join our Telegram channel

Aug 25, 2016 | Posted by in CARDIOLOGY | Comments Off on Descending Thoracic Aorta to Femoral Bypass

Full access? Get Clinical Tree

Get Clinical Tree app for offline access