Abdominal Aortic Endografting:
Fixation and Sealing
Roy K Greenberg,
MD
The treatment goals for elective endovascular and open
surgical repair of abdominal aortic aneurysms are iden-
tical. Anyone attempting to remedy this condition de-
sires longterm freedom from aneurysm rupture in asso-
ciation with minimal morbidity and mortality for the
intervention required. The methods by which these ob-
jectives are achieved differ significantly between open
and endovascular procedures. This article will address
the means by which endografts achieve proximal fixa-
tion and sealing, two concepts that are paramount in
durable endovascular aneurysm repair.
The surgical anastomosis, when properly con-
structed, is the most secure way to fixate graft material to
a section of normal arterial wall. This serves to prevent
flow outside of the designated conduit and to secure the
graft material in place. Although this is conceptually
straightforward, individuals who treat this condition
maintain a healthy respect for the potentially complex
anatomy of the proximal neck. The ability to make ad-
justments while sewing the proximal anastomosis is ex-
tremely advantageous. Similar situations can be encoun-
tered during endovascular aortic repairs, but we are
frequently unable to modify the device or technique
once the procedure has been initiated. Consequently,
the preoperative imaging and planning is critical to suc-
cessful endovascular grafting. Appropriate patient selec-
tion, the conceptual design of an endovascular graft, and
detailed planning of the operation must be completed
before arrival in the operating room.
Most assessments of acute technical and clinical suc-
cess of endovascular grafting have been quite favorable,
but complex analyses of longterm durability raise con-
cerns that dwarf the early favorable results. The inevita-
ble deterioration of the arterial system associated with
age and accelerated by aneurysmal disease, in conjunc-
tion with morphologic changes associated with sac
shrinkage, requires endovascular prostheses to adapt to
altering anatomy. Endograft design must be tailored to
specific anatomic factors that must be determined pre-
operatively, and acute success, with respect to proximal
fixation and sealing methods, must be coupled with ma-
terials that will accommodate anatomic changes.
IMAGING OF THE PROXIMAL NECK
The proximal neck has been the subject of a great deal of
controversy. To the initiate, the proximal neck may ap-
pear easily definable, but the experienced interventionist
realizes how complex it is to define the limits of healthy
aorta based on preoperative imaging studies. We use
cross-sectional images obtained from high-resolution
spiral CT scans to help us delineate the proximal neck.
Data are acquired and reconstructed to provide 2- to
3-mm cuts of the visceral aortic segment through the
entire aneurysm and pelvis. Although older techniques
were incapable of this accuracy, recent advances in CT
technology have rendered this resolution of imaging
routine. The assessment of the proximal neck requires
careful scrutiny of these images with attention directed
toward diameter measurements, length, angulation, de-
bris within the aorta, calcification, and morphology.
Many of these characteristics are difficult to quantify but
still deserve discussion. The fundamental concept is to
differentiate relatively normal aortic tissue from un-
healthy, potentially unstable artery.
Diameter changes, in conjunction with unusual mor-
phology, are used to define the extent of the proximal
neck, allowing one to calculate a length of relatively
normal aortic tissue. We use an absolute cutoff of a 10%
diameter change as indicative of unhealthy tissue. For
example, if a continuous segment of 25-mm suprarenal
Dr Greenberg receives funding from Medtronics, WL Gore, Edwards Life-
sciences, Cook Inc, and Guidant. He is a consultant for Cook Inc and Sultzer-
Vascutek. Some devices mentioned are not FDA approved in the USA but are
available elsewhere.
Received April 18, 2001; Revised August 8, 2001; Accepted September 19,
2001.
From the Department of Vascular Surgery, The Cleveland Clinic Foundation,
Cleveland, OH.
Correspondence address: Roy K Greenberg, MD, Department of Vascular
Surgery, The Cleveland Clinic Foundation, Desk S-61, 9500 Euclid Ave,
Cleveland, OH 44195.
S79
© 2002 by the American College of Surgeons ISSN 1072-7515/02/$21.00
Published by Elsevier Science Inc. PII S1072-7515(01)01097-3