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Chapter 9 Fenestrated Endovascular Stent-Grafts: Current Applications 151
A complete comprehensive step-by-step technical approach has recently been
published.
9
The increased complexity of fenestrated endograft deployment includes
additional steps to the standard EVAR technique. The main body of the graft has
to be partially deployed in the aorta, with a partially expanded diameter. For this
purpose, diameter reducing ties constrain the graft to allow repositioning of the
main body of the graft and catheterization of the fenestrations from the contralateral
femoral artery (Fig. 2 ). Selective catheterization of the renal arteries is essential
for correct deployment of the graft with the fenestrations aligned with the orifice
of these vessels. It is important to realize that vessel catheterization can only be
achieved by repositioning the graft until the fenestration faces the target vessel
orifice. To facilitate correct position under fluoroscopy, fenestrated grafts have four
radio-opaque markers around each fenestration, and three around scallops. The
complete deployment of the graft requires releasing the diameter reducing ties and
opening the top cap. The scallop for the superior mesenteric artery, if present, should
automatically fall into position, without necessitating additional catheterization.
Evolution of the Technique
Over the years, a number of technical refinements related to the stent-graft
configuration and various technical steps required for insertion of the graft
have been introduced, to standardize the technique and increase the rate of
Fig. 2 Diameter Reducing Ties
Constraining The Deployed Graft
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152 E.L.G. Verhoeven et al.
technical success. Fenestrated bifurcated grafts have evolved towards
composite grafts. Composite grafts include a tube graft containing the fenes-
trations which is deployed first, followed by a bifurcated graft, and completed
with a contralateral limb. A tubular proximal body, including the fenestra-
tions, is much easier to reposition during catheterization of the renal arteries.
Deployment is easier and safer, without risk of torsion of the ipsilateral limb
during repositioning ( see “Results”). Another advantage of the composite sys-
tem is the lower downwards migration force on the tubular part of the system
containing the fenestrations.
An additional important improvement of the technique has been the
application of routine stenting of renal artery fenestrations to optimize the
appositioning. Even with meticulous pre-operative measurements and intra-
operative positioning, renal artery appositioning with the graft fenestration
may not be perfect since the procedural angiogram is unable to demonstrate
the degree of appositioning accurately. The purpose of the renal stents is to
optimize the apposition between fenestrations and ostia of the target vessels,
and also to maintain this correct position over time. To provide better support
to the stents, all fenestrations are now reinforced with a double nitinol ring.
Finally, a better technique to guarantee the safe introduction and deployment
of the stents has been developed. In the early stages, full deployment of the
graft was executed with balloons inside the fenestrations and target vessels.
Afterwards, the balloons were deflated and removed to allow insertion of the
stents. This sequence carried a risk of loosing renal access, due to the stiffness
of the stents. Currently, guiding catheters/sheaths are routinely introduced
into the renal arteries. In this manner, the stents can be advanced through the
guiding catheters before deploying the graft completely (Fig. 3 ). This guaran-
tees safe deployment of the stents once the graft is fully open and the guiding
Fig. 3 Guiding catheters passing the fenestrations and positioned inside the renal
arteries
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Chapter 9 Fenestrated Endovascular Stent-Grafts: Current Applications 153
sheath retracted. To prevent distal migration at the time of full deployment, it
is advisable to push up the device slightly to counteract the aortic flow push.
This manoeuver allows embedding of the hooks and minimizes downwards
migration.
10
Other improvements to this technique include ballooning of the proximal
two stents of the main body graft before inserting stents into the renovisceral
vessels. This improves apposition of the graft material against the aortic wall
and results in a more secure position of the stents. It is important to allow
sufficient overlap between the different graft components (i.e., at least three
stents overlap between first tubular and second bifurcated graft, and 1.5 stents
overlap between gate and contralateral limb).
Finally, it is essential to understand that meticulous pre-operative aortic
measurements and planning are the key to technical success.
Current Applications of Fenestrated Endografts
From the anatomical point of view, fenestrated endografts are designed to
treat infrarenal aortic aneurysms with a neck too short for standard EVAR. It
is important to realize that appositioning of the graft against the wall is essen-
tial. Infrarenal aneurysms with a neck varying from 4 to 15 mm in length are
most suitable for this technique. To treat juxtarenal, suprarenal, and TAAA,
additional technical features are required. Turning a fenestrated graft into a
branched graft by using covered stents instead of uncovered stents was an
option, and developing truly branched grafts another. Both techniques are
feasible and present with specific advantages and disadvantages.
For juxtarenal aneurysms, the fenestrated graft in conjunction with covered
stents seems to be the logical option. The covered stent will not only provide
apposition but also a seal with the fenestration. A safe seal with the aortic wall
can be achieved if there is a sufficient neck available in the aortic portion between
the celiac trunk and the renal arteries (
Fig. 4a and b ). By using multiple (up
to four) small fenestrations and fitting each of them with covered stents, it
becomes possible to treat suprarenal and TAAA, as demonstrated by Anderson
et al.
11
(Fig. 5a and b ). The Achilles' Heel of this technique is the questionable
stability and durability of the seal between the nitinol ring of the fenestration
and the covered stent, especially when there is a long gap to bridge from the
fenestration to the ostium of the target vessel, such as in most TAAA. Exact
positioning of the graft and the fenestrations is mandatory with this technique.
Advantages of the technique are that the graft is not more bulky than a stand-
ard stent-graft and can be fitted in 22-Fr delivery systems, and that it is similar
to the fenestrated technique used for short-necked aneurysms .
The second and probably better option for most TAAA is perhaps a fully
branched endograft. This concept was initially developed by Chuter.
12
The
theoretical advantage is that a branch provides a better seal and fixation for the
bridging stent-graft. Another advantage is the less critical need to accurate posi-
tioning the graft branches relative to the target vessel orifices. Disadvantages
include the required approach from the arm to catheterize the branches and
target vessels, and the stiffness of the current range of available bridging stent-
grafts. Because most side branches are directed straight downwards, the bridg-
ing stent-grafts have to accommodate an angle of up to 90° to enter the renal
arteries, bearing in mind the physiological forces that promote kinking and
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154 E.L.G. Verhoeven et al.
occlusion of branched endografts (Fig. 6 ). To prevent this, a self-expandable
stent can be additionally inserted inside the bridging stent-graft. The excess
of fabric created by the side branches makes these branched grafts more bulky
which often results in larger bore delivery systems.
Greater complexity sets apart this type of endovascular surgery from
standard EVAR. Initially, we reserved the fenestrated technique for selected
high-risk surgical patients only. This selection was either based on systemic
co-morbidity (cardiac, renal, pulmonary) or because the patients presented
with a hostile abdomen, precluding laparotomy or at least making laparotomy
difficult and risky. With growing experience and confidence in the procedure,
a more liberal use of the technique has included patients who are acceptable
candidates for open surgery. However, an important number of patients are
referred to us by other surgeons because of hostile abdominal conditions.
These include patients with multiple laparotomies and those who require redo
aortic surgery after previous open or endovascular aortic surgery.
13
Finally,
patients are only accepted for fenestrated stent-grafting if their aneurysm was
Fig. 4 (a) Pre-operative CT-scanning showing a juxtarenal aneurysm. (b) Post-operative CT-scanning reconstruc-
tion after fenestrated stent-grafting. Two covered stents were inserted in the renal artery fenestrations not only to
optimize apposition but also to create a seal (See Color Plates)
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Chapter 9 Fenestrated Endovascular Stent-Grafts: Current Applications 155
Fig. 6 Completion angiogram showing kinking
in the two bridging stent-grafts to the renal arter-
ies (arrows)
Fig. 5 ( a ) Pre-operative CT-scanning of a suprarenal aneurysm reaching to the level of the superior mesenteric
artery (AMS, arrow). ( b ) Post-operative CT-scanning showing a graft with a short upwards facing branch for the
left renal artery, two fenestrations for the right renal artery and the superior mesenteric artery, and a scallop for
the celiac trunk (See Color Plates)
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156 E.L.G. Verhoeven et al.
large enough to justify treatment with this complex technique; this was defined
as aneurysm with a maximal diameter of at least 5.5.cm for men and 5.0 cm
for women. In patients with smaller aneurysms, conservative treatment with
routine aneurysm surveillance was advocated.
Limitations of the Technique
The limitations of the standard fenestrated technique become obvious con-
sider ing the necessary steps for deployment. The graft needs to be repositioned
to its final position during catheterization, and the insertion of the renal stents
must be achieved correctly. Every anatomical feature rendering these two
processes difficult to execute makes this already complex technique even more
challenging. Severe angulation of the neck or iliac arteries, narrow iliac arter-
ies, and previously inserted surgical grafts can all pose problems to reposition
the graft. Insertion of stents into the renal arteries and renal artery patency are
questionable in case of small or diseased renal arteries, short renal arteries
with early bifurcations, and a sharp takeoff of the renal arteries. Other anato-
mical peculiarities can also increase the difficulty of this procedure: aortic side
branches in proximity to each other render designing the graft more difficult,
angulation of the neck makes difficult to determine the correct level of the
small fenestrations for the renal arteries, thrombus inside the proximal neck
poses a risk not only for endoleak but also for embolization during reposition-
ing, and a small neck diameter can render the catheterization process more
difficult because of the small space to manoeuver with shaped catheters.
Results
Our experience with different fenestrated and branched grafts includes 166
patients (Table 1 ). In Table 1 , all fenestrated grafts fitted with covered stents,
as well as hybrid grafts (combination of true branches and fenestrations), were
classified as branched. With regard to procedure and follow-up, we dealt with
three categories of patients: first, patients who have both the procedure and
follow-up in our hospital; second, patients that were treated in our hospital but
were followed by other centres; and third, patients that were treated in another
hospital in conjunction with a Groningen team member. This situation is probably
similar to other specialized centres and presents important consequences
for follow-up reporting. Most reported results, albeit from a few specialized
Table 1 Fenestrated and branched stent-graft experience
in Groningen, according to anatomical location and type
of stent-graft.
Location Fenestrated Branched Total
Abdominal 79 48 127
Thoracic (arch) 3 1 4
Thoraco-abdominal aortic
aneurysm (TAAA)
6 9 15
Iliac branched 20 20
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Chapter 9 Fenestrated Endovascular Stent-Grafts: Current Applications 157
centres only, are good, with mortalities in the range of standard EVAR and a
target vessel patency of around 95%.
14–
16
Nevertheless, renal arteries need to
be carefully monitored as imperfect technical results can lead to complications
and eventually renal artery occlusion.
17
Our own results are encouraging, including published mid-term outcome.
13,
18
In the present study, we report on 76 patients (category I with procedure and
follow-up in our hospital) who had a fenestrated/branched graft for complex
aortic aneurysms (short-necked, juxta-, and suprarenal aneurysms, TAAA
excluded). Technical success was 81/84 (96%) patients: in one case, we
aborted the procedure in favour of a shorter quicker standard procedure
with intentional sacrifice of two accessory renal arteries; in a second case, a
heavily stenosed renal artery was treated surgically the day after the initial
procedure; the third case (juxtarenal aneurysm after previous open surgery)
had to be converted to open surgery. The reason for this conversion was
that the bifurcated fenestrated graft became twisted and the top cap stuck.
In this particular case, it was impossible to use a composite three-part graft
due to length issues. Fortunately, the patient made an uneventful recovery.
The overall mortality was 1.2%. One patient died 8 days after surgery from
mesenteric ischaemia. Autopsy revealed a patent superior mesenteric artery.
During follow-up, 10 (12%) patients died between 4 and 51 months after the
procedure of unrelated causes. Occlusion occurred in 7 of 211 (3.3%) target
vessels, all being renal arteries. As a result, seven (5%) kidneys were lost, but
none of the patients required dialysis. If we exclude the 4 patients that had no
technical success (3) or died (1), the risk of loosing a renal artery in a patient
is 7/80 or 8.7%. Renal function overall remained stable during follow-up, but
aneurysm size decreased significantly and no proximal type I endoleaks were
seen. Reinterventions were required in 9/83 patients (10.8%); one patient
excluded who received standard endovascular repair, but there were no late
transabdominal reinterventions. These include three reinterventions within 30
days: one conversion, one surgery at day 1, and one laparotomy at day 7 in
the patient who died from mesenteric ischaemia (all three mentioned above).
There were six late reinterventions, three of which were angiographies with or
without renal artery stenting. Two patients had angiographic reinterventions
for type II endoleaks. Finally, the last patient developed a late groin infection
that eventually needed surgical debridement.
Conclusion
Although the fenestrated endograft technique is still not widely available, there
are several reasons to warrant its further development and careful widespread.
First, the results with fenestrated grafts for short-necked and juxtarenal aneu-
rysms are good in the expert hands. Second, the advantages of a less-invasive
technique are probably greater in more complex aneurysms such as suprarenal
and TAAA because of the high morbid–mortality of open surgery. Finally, we
will always encounter patients who are at high surgical risk, due to co-morbid
conditions, hostile abdomen, or with previous aortic surgery.
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158 E.L.G. Verhoeven et al.
References
1 . Greenhalgh RM , Brown LC , Kwong GP , Powell JT , Thompson SG . EVAR trial
participants. Comparison of endovascular aneurysm repair with open repair in
patients with abdominal aortic aneurysm (EVAR trial 1), 30-day operative mortal-
ity results: Randomised controlled trial . Lancet 2004 ; 364 : 843 – 8 .
2 . Prinssen M , Verhoeven EL , Buth J , et al . A randomized trial comparing conven-
tional and endovascular repair of abdominal aortic aneurysms . N Engl J Med
2004 ; 351 : 1607 – 18 .
3 . EVAR trial participants . Endovascular aneurysm repair versus open repair in
patients with abdominal aortic aneurysm (EVAR trial 1): Randomised con-
trolled trial . Lancet 2005 ; 365 : 2179 – 86 .
4 . Blankensteijn JD , Jong de SE , Prinssen M , et al . Two-year outcomes after con-
ventional or endovascular repair of abdominal aortic aneurysms . N Engl J Med
2005 ; 352 : 2398 – 405 .
5 . Leurs LJ , Stultiëns G , Kievit J , Buth J . Adverse events at the aneurismal neck
identified at follow-up after endovascular abdominal aortic aneurysm repair:
How do they correlate ? Vascular 2005 ; 13 : 261 – 7 .
6 . Jean-Claude JM , Reilly LM , Stoney RJ , Messina LM . Pararenal aortic aneurysms:
The future of open aneurysm repair . J Vasc Surg 1999 ; 29 : 902 – 912 .
7 . Zeebregts CJ , Geelkerken RH , Palen van der J , Huisman AB , Smit de P , Det van
RJ . Outcome of abdominal aortic aneurysm repair in the era of endovascular treat-
ment . Br J Surg 2004 ; 91 : 563 – 568 .
8 . Verhoeven EL , Prins TR , Tielliu IF , et al . Treatment of short-necked infrarenal
aortic aneurysms with fenestrated stent-grafts: Short-term results . Eur J Vasc
Endovasc Surg 2004 ; 27 : 477 – 83 .
9 . Moore R , Hinojosa CA , O’Neill S , Mastracci TM , Cina CS . Fenestrated endovas-
cular grafts for juxtarenal aortic aneurysms: A step by step technical approach .
Catheter Cardiovasc Interv 2007 ; 69 : 554 – 71 .
10 . Zhou SSN , How TV , Vallabhaneni SR , Gilling-Smith GL , Brennan JA , Harris PL ,
McWilliams R . Comparison of the fixation strength of standard and fenestrated
stent-grafts for endovascular abdominal aortic aneurysm repair . J Endovasc Ther
2007 ; 14 : 168 – 75 .
11 . Anderson JL , Adam DJ , Berce M , Hartley D . Repair of TAAA with fenestrated
and branched endovascular stent grafts . J Vasc Surg 2005 ; 42 : 600 – 7 .
12 . Chuter TA , Gordon RL , Reilly LM , Goodman JD , Messina LM . An endovascular
system for thoracoabdominal aortic aneurysm repair . J Endovasc Ther 2001 ; 8 :
25 – 33 .
13 . Verhoeven EL , Muhs BE , Zeebregts CJ , Tielliu IF , Prins TR , Bos WT , et al .
Fenestrated and branched stent-grafting after previous surgery provides a good
alternative to open redo surgery . Eur J Vasc Endovasc Surg 2007 ; 33 : 84 – 90 .
14 . Anderson JL , Berce M , Hartley DE . Endoluminal aortic grafting with renal and
superior mesenteric artery incorporation by graft fenestration . J Endovasc Ther
2001 ; 8 : 3 – 15 .
15 . Greenberg RK , Haulon S , Lyden SP , et al . Endovascular management of juxtarenal
aneurysms with fenestrated endovascular grafting . J Vasc Surg 2004 ; 39 : 279 – 87 .
16. Scurr JRH, Brennan JA, Gilling-Smith GL, Harris PL, Vallabhaneni SR, McWilliams
RG. Fenestrated endovascular repair for juxtarenal aortic aneurysm Br J Surg 2007
(in press).
17 . Haddad F , Greenberg RK , Walker E , et al . Fenestrated endovascular grafting: The
renal side of the story . J Vasc Surg 2005 ; 41 : 181 – 90 .
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Abstract Pararenal abdominal aortic aneurysms (AAAs) are classified
as to being juxtarenal or suprarenal. They account for 2–7% of all aortic
aneurysms, with men affected twice as often as women. Precise anatomic
imaging with computed tomographic arteriograms or conventional aortogra-
phy is required for optimal surgical therapy. The morbidity of open surgical
repair is most often related to renal insufficiency. The operative mortality
averages 5% being slightly greater than that accompanying open infrarenal
aortic aneurysmectomy.
Keywords Pararenal aneurysm , Juxtarenal aneurysm , Suprarenal aneurysm ,
Aortic aneurysm surgery
Introduction
Pararenal AAAs account for 2–7% of all aortic aneurysms. The open surgical
treatment of pararenal AAAs is complex and requires a detailed knowledge of
the anatomic disease, careful attention to thorough preoperative patient prepa-
ration, precise operative intervention, and contemporary intensive care in the
early postoperative period.
Pararenal AAAs are classified as juxtarenal or suprarenal, depending on involve-
ment of the renal artery (Fig. 1 ). Juxtarenal AAAs outnumber suprarenal AAAs,
4-to-1. Juxtarenal AAAs extend superiorly to just below the renal arteries such
that no normal aorta exists between the aneurysm and the renal arteries.
Suprarenal AAAs extend superiorly to include the orifices of the renal arter-
ies to one or both kidneys. Pararenal AAAs, by definition, do not involve
the superior mesenteric or celiac arteries, or extend above the diaphragm to
involve the thoracic aorta. Coexistent renal artery arteriosclerosis is near uni-
versal with pararenal AAAs, but it is severe enough in only 10–25% of cases
to cause renovascular hypertension or ischemic nephropathy.
Chapter 10
Open Surgical Treatment of Pararenal
Abdominal Aortic Aneurysms
James C. Stanley
G. Upchurch and E. Criado (eds.) Aortic Aneurysms, Contemporary Cardiology
DOI: 10.1007/978-1-60327-204-9_10, © Humana Press, a part of
Springer Science + Business Media, LLC 2009
159
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160 J.C. Stanley
Clinical Presentation
Most pararenal AAAs are asymptomatic. In contemporary times, pararenal AAAs
are usually discovered as incidental findings during imaging studies undertaken
for other illnesses. The average age at the time of diagnosis is 67 years. Men are
twice as likely as women to have pararenal AAAs.
1– 4
This gender predilection is
not as great as the 3.5- to 4-fold male predominance that exists with infrarenal
AAAs. It is conceivable that the increased proportion of women having parar-
enal AAAs compared to infrarenal AAAs may be due to practice patterns with
more common delays in treating women until their AAAs become larger. It is
well known that larger AAAs carry a greater likelihood of aneurysmal changes
in the more cephalic pararenal aorta. However, it is also possible that following
menopause, the loss of reproductive hormones such as estrogen that enhance both
elastin and collagen cross-linking may contribute to a more generalized form
of aortic dilation, such that when infrarenal AAAs evolve in women, the juxta-
renal aorta and suprarenal aorta are also likely to exhibit aneurysmal changes.
Considerable anecdotal experience exists to support this contention.
Pararenal AAAs are usually larger than infrarenal AAAs. Nevertheless, their
recognition on physical examination is uncommon. A definitive diagnosis of a
pararenal AAA requires sophisticated imaging. In addition, the renal artery anat-
omy must be precisely delineated to plan optimal therapy of these aneurysms.
Computed tomograms and 3-D tomographic arteriography are the studies used
most often in contemporary practice (Figs. 2 and 3 ). Conventional arteriogra-
phy is also frequently used (Fig. 4 ). Both the former studies require the use of
iodinated contrast with its nephrotoxic risks. Magnetic resonance arteriography
(MRA) is a frequent screening study, often obtained because of its noninvasive
nature and avoidance of using nephrotoxic agents. However, in the case of
Fig. 1 Pararenal aortic aneurysms: Juxtarenal aneurysms ( a ) outnumber suprarenal aneurysms ( b ), 4-to-1. Reprinted
with permission from Henke and Stanley.
26(p. 229)
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