Acute Aortic Disease.. - Index of

Endovascular Thoracic Aortic Stent Grafting 271
descending aorta), of large caliber (to contain the thoracic aortic endoluminal
graft), and relatively stiff (to allow “pushability” through the ileo-femoral access
points and through the abdominal aorta). The management of delivery of the
thoracic aortic stent graft is often the most challenging aspect of the case.
Delivery systems of the current FDA approved Gore TAG (W. L. Gore Flagstaff,
A2) graft require sheaths ranging in size from 22 Fr to 24 Fr outer diameter. Other
devices, which have not been FDA approved, have similar size requirements for arterial
access, either with or without sheaths. Therefore, arterial access size must be
7.5–8.0 mm ID to be considered as a conduit.
Not only the size of the arterial vessels but the anatomy of the ileo-femoral
and abdominal aorta must be considered when planning the access route. Excessive
tortuosity and atherosclerosis with occlusive disease may provide barriers to safe
delivery of the endograft. In approximately 20% of patients, retroperitoneal access
to the common iliac arteries will be required due to issues of femoral or external
iliac artery size and/or tortuosity (2,3).
Careful review of preoperative studies will indicate which patients will have
difficult access. Patients with atherosclerotic occlusive iliac disease may be treated
with standard endovascular balloon angioplasty techniques to reduce the obstruction.
Iliac stents should be avoided due to the potential interference of these stents
with the thoracic aortic access devices. These procedures on the access vessels
should be carried out at least six weeks before thoracic aortic stent grafting to
allow healing of the iliac postangioplasty and manipulation. At the completion
of thoracic aortic endografting, iliac stents may be placed if appropriate.
Access to the retroperitoneum allows several options for safe device deployment.
The common iliac artery may be used for device deployment. An open
surgical conduit can be constructed via an end-to-end anastomosis or a side-to-side
anastomosis. A 10 mm Dacron conduit is commonly used and allows ample size
for insertion of all necessary devices. The conduit may be brought through a separate
counter-incision in the groin to allow better angulation of the relatively long
and stiff deployment devices. At the conclusion of the procedure, these conduits
may be used to revascularize distal obstructions if needed (Fig. 1A) (4).
Alternatively, the retroperitoneal iliac vessels or even the distal aorta may be
accessed using direct sheath insertion. A double pursestring of 4 – 0 Tycron is used
to secure the vessel and provide hemostasis with the application of two sets of
tourniquets. Direct needle puncture of the artery is followed by dilation and insertion
of the device. At completion, the device is removed and the pursestring sutures
are tied down (Fig. 1B) (4). Excessive tortuosity of the ilio-femoral arteries requires
adaptive strategies. The use of external manual manipulation provides a simple
method of straightening some of the tortuosity of the aorta and iliac arteries. During
fluoroscopy the operator’s hand can provide gentle force to the tortuous arterial
segment to allow straightening and subsequent endovascular access.
In cases of iliac artery tortuosity, advanced endovascular techniques may aid
in straightening these segments. The use of stiff wires or buddy wire techniques
can provide some degree of straightening of the diseased arteries. In severe cases