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8
Aorto‐Iliac Interventions
Michael S. Segal1, Sameh Elrabie1, and Rajesh K.
Malik
2
1
Department of General Surgery, Wyckoff Heights
Medical Center, Brooklyn, NY, USA
2
Division of Vascular Surgery, Wyckoff Heights
Medical Center, Brooklyn, NY, USA
Introduction
Obtaining computed tomographic angiography (CTA)
improves preprocedural planning for aortoiliac disease.
Planning should include anticipating any potential
pitfalls and including potential bailout options in the
plan. Access should be obtained dependent on the lesion
location determined from preprocedural imaging and
may require multiple sites of access. Shorter, less
complex lesions are best treated with a self‐expandable
stent. Longer, complex, calcified lesions are better
treated with covered stents and protect against potential
rupture during deployment. If you require precise
deployment, then consider using a balloon‐expandable
stent.
Preoperative Workup
Preprocedural planning and imaging is key to
performing successful aortoiliac interventions. This
workup begins with diagnostic studies to assess the
disease location, extent of disease, calcifications, and
gain an appreciation for potential pitfalls that may be
encountered during therapeutic intervention [1].
Appropriate preprocedural workup can reduce contrast
load for the patient, radiation exposure to the provider,
and improve safety and success rates.
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Noninvasive Studies
Computed Tomographic Angiography
Computed tomographic angiography (CTA) has become
the most utilized imaging modality for preoperative
planning. A CTA provides substantial information,
including potential access‐related issues, length and
complexity of the lesion, extent of calcifications, and the
size of the vessels. This essential information can help
minimize procedure‐related complications by helping
formulate a safe strategy to treat. We strongly
recommend obtaining CTA imaging prior to
interventions (Figure 8.1).
Key Point: Obtaining a high‐quality CTA allows for
thorough preoperative planning.
Figure 8.1 A 3D reconstruction of CTA imaging
demonstrating extensive calcifications and an occluded
left iliac artery.
Ultrasound Duplex
Ultrasound (US) is another imaging modality that can be
used in the initial part of the workup, however, from a
practical standpoint, is limited in its utility for aortoiliac
interventions. This is secondary to being user dependent
and limited by patient habitus above the inguinal
ligament. Additionally, bowel gas patterns can limit the
utility of US. An exercise ankle‐brachial index may be
more helpful if there is suspicion of a proximal lesion.
Magnetic Resonance Angiography
Magnetic resonance angiography is not routinely used in
our practice as there is no benefit over CTA, which is
easier to obtain and, in our view, provides much more
useful information.
Invasive Imaging
Angiography
Angiography is rarely used in planning unless a CTA or
MRA was not able to be performed. During angiography,
morphologic characteristics of the diseased segments
and pressure gradients can be measured to assess
questionable iliac lesions. A pressure gradient of 20
mmHg or greater is considered significant [2]. In our
practice, aortoiliac angiogram is performed with the
intention to treat, unless the disease encountered is not
amenable to endovascular intervention.
Classification of Lesion and Planning
of Intervention
TransAtlantic InterSociety Consensus II
Classification (TASC II)
TASC A and B lesions were amenable to endovascular
interventions with positive outcomes and patency rates.
Historically, TASC C and D lesions were treated with
open surgical intervention. As endovascular
interventions have improved, increasingly complex
lesions are being approached endovascularly. TASC C
and D lesions can now be treated endovascularly with
patency rates approaching surgical patency rates [3]
(Figure 8.2).
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Planning for the Intervention
After the imaging has been reviewed, a treatment plan
should be formulated. This plan should include the
location of the access and the basic equipment that needs
to be used during the procedure, including wires,
balloons, and various stents. It is important to have
appropriate bailout equipment available should a
complication be encountered. This includes having larger
sheaths available, covered stents, and an aortic occlusion
balloon.
Step 1. Patient Factors
Aortoiliac interventions are best performed with light
sedation. This is important because significant pain
during the intervention, such as ballooning the artery,
may indicate that the artery is stretching beyond its
threshold and could risk rupture.
Figure 8.2 TASC II classifications for aortoiliac
occlusive disease.
Step 2. Vascular Access
In planning aortoiliac interventions, access site selection
is an important consideration. Options for access include
femoral, brachial, or radial arteries. Radial access is an
up‐and‐coming option but still slightly limited by
equipment lengths, although that is changing rapidly.
Terumo® makes a 6 Fr 119 cm R2P Destination slender
sheath® with a 5 Fr outer diameter. Through this a self‐
expandable stent, up to 8 mm, can be deployed to the
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iliac arteries. In our practice, we typically use either
femoral or brachial artery access, occasionally requiring
multiple access sites. The location of the lesion and
anatomic factors will ultimately determine which access
site is preferable [2].
Access site selection is determined by the location of the
lesion. A common iliac lesion is treated from the
ipsilateral common femoral artery (CFA) or brachial
artery. An external iliac lesion is treated from the
contralateral CFA or brachial artery. If the lesion is in the
proximal portion of the external iliac artery, an
ipsilateral approach can be considered. Multiple access
sites may be necessary when treating more complex
lesions extending up to and including the infrarenal
aorta. In these cases, bilateral femoral artery access or a
combined brachial and femoral access can be utilized.
There are considerations for access to reduce
complications. Access is performed under US guidance.
When performing brachial access and utilizing a larger
sheath, 6 Fr or greater, particularly in women, we
recommend a cutdown to minimize complications. That
seems to be the cutoff size based on our personal
experience.
Sheath selection through which the intervention is done
is an important consideration for the procedure. For
ipsilateral interventions of the common iliac artery, a 7
Fr radio‐opaque Brite‐Tip® sheath is our ideal selection.
The Brite‐Tip sheath or another marker tipped sheath
aids in visualization of the sheath tip so that a stent is not
inadvertently deployed within the sheath. This sheath is
large enough to facilitate the balloon and stent sizes for
the iliac artery, including the larger covered stents that
are utilized as bailout options if needed. A 23 cm sheath
length works well as it can be used to cross the lesion and
facilitate delivery of a balloon‐mounted stent without the
stent dismounting off the balloon. If access from the
contralateral groin is needed for an up and over
approach, a 6 or 7 Fr long sheath will suffice.
Key Point: Utilize appropriate access dependent on
lesion location and use a sheath size to accommodate
potential bailout options.
Step 3. Crossing the Lesion
Once access is obtained a suitable wire is used to cross
the lesion. The wire can be supported with a catheter
providing additional support and directional control. We
prefer to use a 0.038/0.035‐in. platform in our practice;
however, smaller 0.018‐ or 0.014‐in. wires can also be
utilized in certain situations. After the lesion has
successfully been crossed, a stiff 0.035‐in. wire should be
used to support interventions. This helps allow the
devices to track across the lesion and provides a platform
for rapid upsizing of a sheath should a complication be
encountered.
There are additional devices that can aid in crossing of a
difficult lesion. When dealing with an occlusion, one may
enter a subintimal plane and at times re‐entry into the
true lumen can be complex. There are adjunctive devices
that can assist in re‐entry in these difficult
circumstances. The Cordis Outback Re‐entry catheter
®
and Phillips Pioneer Plus Intravascular Ultrasound
(IVUS) Re‐entry catheter® are two such devices that aid
in re‐entry. The Pioneer Plus has the added benefit of
utilizing IVUS to visualize and direct re‐entry [4]. If re‐
entering at the level of the aorta, we try to keep the entry
point as close to the aortic bifurcation as possible to
prevent creating a large dissection which could
potentially propagate and become problematic.
Once the lesion is crossed, the sheath should be upsized
to facilitate delivery of treatment devices. At this point
the patient should be anticoagulated; in our practice, we
typically heparinize the patient as this agent is easily
reversible should any complication arise. We typically
use 70 units/kg or less to heparinize the patients since
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the procedure should be relatively quick once the lesion
is crossed.
Prior to treatment a complete diagnostic angiogram of
the lower extremity must be performed to differentiate
posttreatment emboli from preexisting lesions.
Step 4. Intervention
An initial treatment plan should be formulated prior to
intervention based on preoperative imaging. Once the
lesion has been crossed and an angiogram is performed,
the final treatment plan is either confirmed or altered
depending on extent and complexity of the lesion. Based
on the quality of the preoperative imaging, rarely is the
plan dramatically altered.
The typical vessel diameter for the common iliac arteries
ranges from 7 to 12 mm. The arteries typically taper
down to the CFA with a vessel diameter of 4–9 mm.
The options for treatment are balloon angioplasty, self‐
expanding (SE) bare‐metal stents, SE covered stents,
balloon‐expandable (BE) noncovered stents, and BE
covered stents (Figure 8.3). Balloon angioplasty alone is
rarely used as a final modality given the superior results
with stents [5]. There is less embolization, less risk of
rupture, reduced overall complication, and higher long‐
term patency when stenting. There is some experience
with primary treatment of balloon angioplasty with
Shockwave® and drug‐coated balloon angioplasty, but
not enough to justify recommendation over stenting.
There are at present two landmark trials that have
created the precedence for the selection of stents utilized
for iliac stenting.
Figure 8.3 Commonly used bare‐metal stents.
The Journal of Vascular Surgery in 2016 published the
Covered vs Balloon Expandable Stent Trial (COBEST).
The study concluded that patients who were treated with
covered stents had a lower rate of restenosis followed out
to five years [6]. The difference became even more
profound as the complexity of the lesion increased. TASC
C and D lesions saw the greatest benefit from a covered
stent (Figure 8.4) versus bare‐metal stent.
The Iliac, Common, and External Artery Stent Trial,
commonly referred to as the ICE Trial, published in 2017
compared versus BE stents. The study found that at 12
months there was a statistically significant difference in
the rate of restenosis, 6.1% for SE stents and 14.9% for
BE stents [7]. However, in heavily calcified lesions, there
may not be much benefit for SE stents.
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Figure 8.4 Commonly used covered stents for iliac
intervention.
As a result of these studies, classification of the lesion
being treated is important in determining what type of
stent will be selected. For more shorter, less complex,
and minimally calcified lesions, the utilization of a self‐
expandable stent provides improved patency rates. For
longer, more complex, and heavily calcified lesions, the
utilization of a covered stent provides a more durable
treatment and protects against risk of rupture. In
general, in the common iliac artery, when we require
precise placement at the ostium or to avoid covering the
internal iliac artery, we prefer to use BE stents. In the
external iliac artery, we prefer to use SE stents, and if
heavily calcified, we use a covered SE stent which is more
amenable to bending at the level of the groin.
Other considerations involve the use of specialized
devices to aid in the treatment of specific pathologies.
One such device is Shockwave angioplasty. This device
allows for balloon angioplasty with lithotripsy delivered
to a calcified vessel wall. This can be used in vessel
preparation prior to stent deployment by improving
vessel compliance [8]. An additional treatment option,
however off IFU, that can be considered is the use of an
Endologix AFX Unibody Endograft® for TASC D lesions.
There were promising results with primary patency rates
of greater than 90% at one year [9].
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