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198
Fig. 17.1 Abdominal aortic aneurysm classication. AAAs include suprarenal, pararenal, juxtarenal, and infrarenal aneurysms, the latter of which
is most amenable to endovascular therapy
A. Lee and M. D. Dake
Thoracic Aortic Aneurysm (TAA)
Similar to the abdomen, a thoracic aortic aneurysm is a dilation of the vessel diameter wall greater than 50% of the normal
expected size. The extent of the aneurysm can involve the aortic root, ascending aorta, aortic arch, and descending aorta,
including distal extension into the thoracoabdominal region.
Approximately 13% of patients who have had a previously
treated aneurysm were found to have aneurysmal involvement
of other levels of the aorta. More than half of those with thoracic aneurysms had other vascular abnormalities, and 12% of
those with abdominal aneurysms have thoracic aneurysms
[28]. Overall, there is a notable increase in the incidence of
TAAs over the past several decades, likely attributed to vastly
improved imaging and screening [29, 30]. At the same time,
there is an increased incidence of ruptured TAA due to our
aging population [31]. Treatment of TAAs involves understanding the various etiologies and risk factors of the disease
process in order to provide optimal management.
The etiologies and pathogenesis differ between ascending
and descending aortic aneurysms. Some studies indicate that
these differences between ascending and descending aneurysms may be related to the differing embryologic origins of
ascending aorta (neural crest cells) and descending aorta
(paraxial mesoderm) smooth muscle cells [32]. Each cellular
origin is predisposed to its own proteolytic factors, which
initiate an inammatory cascade that converge to inltrate
the vessel wall and modify the structural integrity of the aortic wall. Ascending aortic aneurysms most often result from
medial degeneration which appears histologically as smooth
muscle cell dropout and elastic ber degeneration [10]. This
process leads to overall weakening of the vessel wall, leaving
it susceptible to aneurysmal expansion. This is in contrast to
the descending thoracic aortic in which atherosclerosis is the
major contributor to aneurysm formation.
Other risk factors for TAA include risk factors for atherosclerotic disease (hypertension and smoking), prior aortic
dissection, trauma, infection, connective tissue disorders
(Marfan syndrome, Loeys-Dietz syndrome, Turner syndrome), aortic vasculitides (giant cell arteritis, Takayasu
arteritis), bicuspid aortic valve, and familial thoracic aortic
aneurysm syndrome.
Aneurysms of the thoracic aorta should be categorized into
one of four categories based on their anatomic characteristics:
ascending, arch, descending, and thoracoabdominal aneurysms. Ascending aneurysms arise between the aortic valve
and innominate artery. Arch aneurysms include any aneurysm
that involves the brachiocephalic vessels. Descending aneurysms arise distal to the left subclavian artery. Descending
aneurysms may have a proximal extension in the arch and are
classied on a zone system which is useful for treatment planning (Fig.17.2). Descriptions of the specics of aortic arch
interventions are beyond the scope of this chapter.
Thoracoabdominal aneurysms affect both the thoracic
and abdominal aorta and are further categorized according to
the Crawford classication which was modied by Sa [33].
Thoracoabdominal aortic aneurysms are categorized into
ve types based on aneurysm location and extent (Fig.17.3).
Clinical Indication
Abdominal Aortic Aneurysm
Patients with AAAs are predominantly asymptomatic; the
aneurysm is frequently discovered incidentally during routine
physical exams and imaging studies for unrelated issues or in
an AAA screening program. On physical exam, AAAs can
present as a pulsatile abdominal mass. Symptomatic AAA is
characterized by nonspecic abdominal, back, and/or ank
17 Abdominal andThoracic Aortic Aneurysms
199
pain that can be often difcult for patients to localize.
Depending on the proximal or distal extent of the aneurysm,
pain can be localized to the position of the aneurysm. Patients
can present with limb ischemia since the aneurysm can act as
a nidus for thrombus formation and subsequent distal embolization. Regardless of baseline symptoms, AAA rupture can
present with severe abdominal pain and hemodynamic
instability.
Elective AAA repair is the standard of care for prevention
of rupture, but the risk of rupture must be balanced against
potential procedural risks and postoperative complications.
The primary determinant of rupture risk is maximum aneurysm diameter with larger aneurysms carrying the greatest
risks [13–16]. The observed rate of rupture for AAA <5cm is
less than 5% which increases with size reaching nearly 50%
with those over 8cm. The decision on when to treat and manage asymptomatic AAA has been the subject of debate especially for patient presenting with AAAs between 4.0cm and
5.4cm [12]. Data from two randomized trials clearly demonstrated no survival advantage to early repair for small AAA as
compared to surveillance in participants with asymptomatic
aneurysms sized 4.0–5.5 cm [17–19]. For asymptomatic
patients, several randomized trials comparing observation
with either open or endovascular AAA repair have found that
the risk of AAA rupture generally does not exceed the risk
associated with AAA repair until aneurysm diameter exceeds
5.5cm [18, 20–23]. These collective results from randomized
trials built the foundation for the current guidelines from the
Society for Vascular Surgery to offer AAA repair when diameter exceeds 5.5cm or if symptomatic regardless of size.
Fig. 17.2 Aortic arch zonal anatomy. Descending aortic aneurysms
can extend into the aortic arch. This extension is classied into a zone
system which aids in treatment planning
Key Point
Society for Vascular Surgery guidelines for AAA repair:
• Diameter ≥5.5cm in men, ≥5.0in women
• Rapid enlargement, >0.5 cm/6 month period or
>1cm/year
• Symptomatic
• Rupture
Fig. 17.3 Thoracoabdominal aortic aneurysm Crawford classication,
modied by Sa. Type I arises near the left subclavian artery and
extends to the abdomen but not past the renals. Type II arises near the
left subclavian and extends beyond the renals, frequently to the aortic
bifurcation. This may additionally include an ascending aortic aneu-
rysm. Type III originates in the distal half of the descending aorta
extending beyond the renals. Type IV extends from the diaphragmatic
hiatus to the aortic bifurcation, differentiating it from a suprarenal
AAA.Type V arises from the distal descending thoracic aorta and does
not extend past the renals
200
A. Lee and M. D. Dake
In addition to overall aneurysm size, the expansion rate of
aortic aneurysms serves as an alternative predictor of rupture
and supports the role for early intervention. Observational
studies demonstrate that rapid expansion is independently
associated with advanced age, smoking, severe cardiac disease, and stroke [24, 25]. These patients are typically symptomatic which can produce vague and nonspecic abdominal
discomfort. Regardless of initial diameter, these patients
may benet from early repair if the aneurysm expands by
>0.5cm within 6months or 1cm per year on serial imaging
studies.
Based on randomized cohort data, females present with a
rate of AAA rupture that is three times higher than in men
after adjustment for age, body size, and initial AAA diameter. The mean AAA diameter preceding rupture was 6.0cm
in men but only 5.0 cm in women [26, 27]. Although the
impact on overall and long-term survival remains uncertain,
it is reasonable to offer elective AAA repair to women with
AAA of ≥5cm and men with AAA of ≥5.5cm with acceptable procedure risk.
Thoracic Aortic Aneurysm
In general, thoracic aneurysms typically exhibit no clinical
symptoms. Whether by plain chest X-ray or CT imaging,
they are frequently encountered when imaging for another
reason. Symptoms, when they do occur, are secondary to
mass effect which can include compression upon the recurrent laryngeal nerve, tracheobronchial tree, or central veins.
Aneurysm rupture and dissection can present with acute
severe chest and back pain. This condition can be fatal if not
identied rapidly.
When considering TAA repair, the operator should weigh
the long-term benet of repair with the potential procedural
risks. All societal guidelines support repair of TAAs when
symptomatic, rapidly expanding, and dissecting and/or after
rupture. Thoracic aortic aneurysms occur as an indolent process and tend to grow slowly at 0.1–1.0cm/year depending
on the etiology; however expansion rates can exhibit variability [34]. The rate of growth was noted to be greater for
descending versus ascending aortic aneurysms and dissected
versus non-dissected aneurysms and for those with systemic
connective tissue disorders [10]. The risk for dissection and
rupture correlate directly with aortic diameters. Likewise,
the presence of acute symptoms, concomitant bicuspid aortic
valve, connective tissue disease, or a rapidly expanding aortic diameter also increase the risk for potential rupture and
complications [35].
The annual risk of rupture or dissection is <2% for TAAs
between 4.0 and 4.9 cm with increased risk as the size
increases to nearly 7% for TAAs >6.0 cm [36]. There is a
signicant increase in the risk of rupture or dissection with a
diameter greater than 6.0 cm for an ascending TAA and
7.0cm for a descending TAA [37]. With aneurysm pathology, the aorta loses its inherent natural elasticity and becomes
less able to withstand distention. The mechanical properties
of the aneurysmal aorta deteriorate dramatically as the aorta
enlarges, reaching critical levels associated with rupture by a
diameter of 6cm.
For asymptomatic ascending TAA, recommendations for
repair are based on an end-diastolic aortic diameter of
5–6 cm. For patients with systemic vascular disorders, a
lower threshold for repair could be offered starting at 4.5cm.
Similarly, for the descending aorta, repair is indicated for
diameters >6cm and >5cm for those with genetically disposed risk factors. Other acceptable indications include rapid
expansion ≥5–10 mm per year for aneurysms <5 cm in
diameter while factoring in their etiology [38, 39].
Key Point
Guidelines for TAA repair:
• Ascending diameter >5–6cm
• Ascending diameter >4.5cm for those with vascular disorders
• Descending diameter >6cm
• Descending diameter >5cm for those with vascular
disorders
• Rapid enlargement >5–10mm/year
• Symptomatic
• Dissecting
• Rupture
Conventional Therapy
Abdominal Aortic Aneurysm
Before deciding on the type of intervention (medical, endovascular, open, or hybrid), it is important to consider the
patient’s aneurysm size and location, overall clinical condition, comorbidities, and functional status to determine periprocedural risk [40]. Operator experience and hospital-related
variables are known to have a profound impact on procedural
outcome [41, 42].
Medical therapy is focused on preventing aortic expansion for aneurysms that do not meet size or growth criteria
for treatment through cardiovascular risk reduction and
smoking cessation. Smoking cessation should be promoted
in all clinical settings to improve patient survival including
improved outcomes associated with aortic repair. Likewise,
17 Abdominal andThoracic Aortic Aneurysms
201
unless contraindicated, recommending a regimen of exercise,
antiplatelet, statin, and antihypertensive therapies (goal SBP
<120 mmHg) optimizes cardiovascular health which consequently improves all outcomes associated with aortic aneurysm repair. Other medications such as beta-blockers,
angiotensin receptor blockers or angiotensin-converting
enzyme inhibitors, antibiotics, and anti- inammatory agents
have shown protective effects to aneurysm expansion in retrospective reviews and animal models, but their overall clinical efcacy has yet to be proven.
Open AAA repair involves replacement of the diseased
aorta with prosthetic graft such as polyester (Dacron) or
polytetrauoroethylene (PTFE), autogenous vein, or cadaveric allograft. The graft diameter should complement the
diameter of the native aorta to minimize size mismatch. The
distal aspect of the repair depends on the distal extension of
the aneurysm. If conned to the aorta, a tube graft is often
used for distal anastomosis to the non-aneurysmal distal
aorta; if the aneurysm extends to the iliac arteries, a bifurcated graft can be sewn to the external iliac or femoral arteries. The technique has been consistently performed since it
was rst described in 1952 [43].
In general, exposure to the aorta can be performed through
a transabdominal or retroperitoneal approach. By utilizing a
retroperitoneal incision, the suprarenal aorta can be
approached with an option to extend above the celiac artery
by dividing the diaphragm. Based primarily on surgeon preference, this exposure also avoids previous abdominal incisions while lowering rates of postoperative complications
and enabling quicker recovery. The transabdominal incision
provides adequate exposure of pelvic vasculature including
iliac arteries. Approach is frequently provider and patient
specic; there are no overall noteworthy differences to either
approach in affecting perioperative mortality.
Thoracic Aortic Aneurysm
The earliest report of open thoracic aneurysm repair dates
back to 1951 when Lam and Aram reported the resection of
a descending thoracic aneurysm with allograft replacement
[44]. Similar to AAA management, a thorough preoperative
risk assessment including clinical status, comorbidities, and
functional status should be evaluated. Evaluation may
include pulmonary function testing, echocardiogram with
valvular and left ventricular function, and cardiac catheterization for staging of coronary artery disease [45].
The surgical approach is dependent entirely on the extent
of aneurysm involvement and the presence of healthy native
tissue. Exposure can be gained via a sternotomy or left posterior lateral approach. TAA repair typically requires placing
the patient on cardiopulmonary bypass often with a cardioplegia-arrested heart. There is expected organ ischemic time
depending on which visceral branches are involved. Selective
shunts along with circulatory arrest and hypothermic (32°C)
conditions can minimize interruption of ow and tissue injury.
The diseased aorta is replaced, while the visceral branches are
sewn to a Dacron conduit. The aortic cross clamp is sequentially advanced distally after each reimplantation.
Interventional Therapy
Abdominal Aortic Aneurysm
Endovascular AAA repair (EVAR) has been a revolutionary
advancement in the treatment of AAA (Fig. 17.4). First
reported by Parodi etal., this less invasive and modular aortic
repair system involves delivering stent grafts from the access
vessel(s), usually from the common femoral artery [46].
Fig. 17.4 Infrarenal AAA measuring 5.6cm. (a) 3-D reformatting of
CT angiography with TeraRecon software shows a 3-D rendering of the
infrarenal AAA (top left). The largest aneurysmal dimension measures
5.6cm (bottom left). TeraRecon reformatting straightens the tortuosity
of the vessels using a center line to aid in graft measurements and
branch vessel visualization (right). (b) Aortogram with Endurant
(Medtronic) stent graft in position via the right iliac limb. A marking
pigtail can be seen advanced through the left iliac limb. (c) After
deployment of the stent graft, proximal balloon molding with a Coda
balloon (Cook Medical, Bloomington, IN) is performed to better appose
stent graft to aortic wall. (d) Completion aortogram showing patent
renal and internal iliac arteries status post endograft placement. No
endoleak can be seen
202
A. Lee and M. D. Dake
Deployment of the stent creates a conduit within the aorta
using a stent covered in low-porosity graft material, sealed by
outward force at the proximal and distal contact points in
order to completely exclude blood ow to the aneurysmal
sac. The use of EVAR compared to open repair has been studied across three randomized trials; EVAR clearly exhibited
lower perioperative and short-term (<30days) morbidity and
mortality than open surgical repair [47]. Despite the lower
initial complication rate, EVAR does require far more secondary procedures during the lifetime of the graft; the majority of these procedures can be performed by endovascular
approaches. Since the introduction of endovascular repair, the
annual number of deaths from ruptured AAA has also signicantly decreased, coinciding with an increase in intact treated
AAAs and a decrease in ruptured AAA diagnoses [48].
Although an appealing and relatively safe option for AAA
repair, the drawback of EVAR is the strict anatomic criterion
that is required to yield the most optimal outcome (Table17.1).
Table 17.1 Aortoiliac anatomical conditions for endovascular AAA
repair [51]
Structure Parameters and range
Aortic neck
Diameter 18–32mm
Length >10–15mm
Angulation <45–60°
Common iliac artery
Length >20mm
Diameter 8–22mm
Minimal calcication and tortuosity
External iliac artery
Diameter >7mm
Minimal calcication and tortuosity
This emphasizes the importance of preoperative planning and
understanding the relationship between the anatomical characteristic of the aorta, technical limits, and properties of the
endograft.
Thoracic Aortic Aneurysm
The availability of minimal invasive treatment for thoracic
aortic aneurysms has gained wide recognition because of
the observed improvement in patient outcomes, particularly
in the high-risk cohort (Fig.17.5). As early as 1994, Dake
et al. rst reported the use of thoracic stent grafts for the
treatment of descending thoracic aortic aneurysms in
patients who were believed to be at excessive risk for conventional open surgery [49]. Current data from nonrandomized studies suggest that endovascular repair reduces
perioperative mortality, neurological morbidity, renal insufciency, and cardiac complications compared to open surgery [50, 51]. With fewer overall complications, primary
technical success was highly achievable across many
reported series. Despite the promising results, endoleaks
(6–9%) and re-interventions (2%) are higher in the endovascular group versus open surgical repair group up to 2years
posttreatment [52]. In an early series of 84 patients, major
procedure-related or device-related complications occurred
in 38%, including proximal attachment failure (8%), distal
attachment failure (6%), mechanical device failure (3%),
periprocedural death (6%), and late aneurysm rupture (6%)
[53]. With various commercially available endovascular
grafts, each stent carries their own respective advantages in
regard to prole and ease of delivery, accuracy of deployment, and exible conformation; despite this, there is no
Fig. 17.5 Descending TAA measuring 5.5 cm aneurysm. (a) 3-D
reformatting of CT angiography with TeraRecon software shows a short
descending aortic aneurysm (top left). The largest aneurysmal dimension measures 5.5cm (bottom left). With assistance of center line measurements, precise lengths of stent graft can be obtained while
accounting for visceral branches (right). (b) With device in place, left
anterior oblique aortogram delineates the aneurysm and proximal and
distal landing zone. (c) The Zenith Alpha (Cook Medical) thoracic stent
graft was deployed across the aneurysm. Post-deployment angiogram
demonstrates no evidence of endoleak and a preserved celiac artery
17 Abdominal andThoracic Aortic Aneurysms
203
clear advantage between available devices. Compared with
open surgery, thoracic aortic endovascular repair (TEVAR)
provides much lower perioperative morbidity and mortality
rates, but clearly, technical renements need to be made
before it can become a routine treatment for TAA extending
into the aortic arch or the abdominal viscera [10]. Graft surveillance is also important during the postoperative period
to monitor stent behavior and progression of the patients’
underlying disease to prevent complications.
Planning andKey Concepts forEndovascular
Repair
• Upon initial evaluation, most interventionalists advocate
for dedicated high-quality aortic CT arteriography (CTA)
imaging of the torso at <2.5mm slices to better delineate
the aortic anatomy for specications and device selection.
Additionally, three-dimensional imaging with specialized
software (TeraRecon) processing can provide exact identication of visceral or side branches, angulation, extent
of vessel calcication, presence of intraluminal thrombus,
and vessel diameters. The access sites including the iliac
and femoral arteries need to be evaluated to determine
safety of stent delivery and avoid iliac rupture or disruption. At times, endovascular or surgical conduits are
needed when iliac arteries are too diseased for safe delivery of endografts.
• The proximal and distal landing zones for the stent must
be thoroughly interrogated to ensure adequate stent coverage for full aneurysm exclusion. In general, choosing an
aortic graft with approximately 15–20% oversizing to the
aortic diameter is recommended to ensure coverage and
enough outward radial force to prevent stent migration.
Signicant oversizing (>20%) can cause excessive stent
material fabric to kink and blood can leak around the
graft, incompletely excluding the aneurysm and increasing the risk of retrograde aortic dissection. Undersizing
will yield an inferior repair and increased risk of stent
migration, endoleak, and need for additional and unnecessary interventions.
– For AAA, stent coverage should include the entire aor-
toiliac region from below the renal arteries to the iliac
bifurcation.
– For TEVAR, the stent graft should span the aneurysm
while obtaining approximately a 2-cm seal at the proximal and distal end points. Depending on aneurysmal
location, bypassing supraaortic or visceral branching
vessels may need to be performed as a staged procedure before endovascular treatment.
• With continued advancements in technological devices, it
is important to understand the anatomical indications and
be reasonably comfortable with using a particular stent
graft during endovascular aneurysm repair. Each endograft has its own individual advantage depending on specic patient anatomic situations and operator preference.
The instructions for use (IFU) are published parameters
that are set forth by the device company and designed for
optimal graft usage. Careful preoperative sizing and planning with adherence to device design specications will
yield the best technical and patient outcomes [54].
• These cases are typically performed with general anesthesia to allow for continuous hemodynamic monitoring.
The How To
1. Preoperative imaging will determine whether per-
cutaneous or open femoral access is optimal.
Percutaneous access should be obtained at the
level of the femoral head which can be marked
ral artery is accessed via the Seldinger technique,
frequently using ultrasound guidance.
Alternatively, open exposure of the femoral arteries can be performed, puncture is then performed
under direct visualization, and a 0.035” guidewire
is advanced into the aorta.
2. If percutaneous access is possible, a pre-closure
technique using ProGlide Suture-Mediated
Closure System (Abbott, Abbott Park, IL) is
placed at the initiation of the procedure to facilitate closure of the arteriotomy sites after the case.
Typically for larger sheaths (
8F), two ProGlide
devices will be placed to close the arteriotomy
safely. The process is repeated for the contralateral
access site depending on anticipated sheath size.
3. Throughout the procedure the patient should be
adequately heparinized to minimize the risk of
thrombosis. Typically, an intravenous bolus of
80–100 units per kg is given after arterial access is
safely obtained and additional doses are given to
4. The preoperative CTA is used to determine which
femoral artery will be the primary device side. The
contralateral side will initially hold the pigtail or
similar multi-side-hole injection catheter.
5. The existing guidewire on the primary device side
should be exchanged for a stiff working wire to
facilitate passage of large bore sheaths and
devices.
6. An aortogram is performed through a contralateral
side pigtail or Omni Flush catheter for procedural
7. Device advancement and positioning:
(continued)
204
A. Lee and M. D. Dake
(a) For EVAR, place an Omni Flush catheter
from the contralateral groin at the L1 region
of the vertebral spine, and position the image
undeployed endograft and renal arteries.
(b)For TEVAR, change the angle of the detector
end of the endograft and best visualize arch
vessels.
8. Aortogram:
(a)For EVAR, identify the renal arteries and
position graft just distal to the lowest renal
artery. Sometimes accessory renal arteries
will intentionally be covered to allow adequate proximal seal zone.
(b) For TEVAR, identify location of the aneurysm
and position graft for optimal seal. Depending
on the length of the aneurysm, additional
grafts may be overlapped to extend coverage
distally
9. Device deployment EVAR:
(a) Deploy main body until contralateral gate is
opened. Hold device in place.
(b) Cannulate the contralateral gate from contra-
lateral femoral access with an appropriately
main body and not behind or in front of it by
trast, or spinning a pigtail catheter.
(c) Perform a retrograde arteriogram from contra-
lateral femoral introducer sheath with catheter
containing 1-centimeter markings to measure
the length of the iliac limb, accounting for
required due to differences in the diameter of
the proximal and distal landing zones.
(b)
of this chapter.
11. Balloon molding with a compliant balloon is
performed on the proximal aortic seal zone, overlapping regions, and distal end points.
12. Completion aortogram is performed to evaluate
for endoleak (refer to Chap. 19 for more information on endoleaks).
13. Percutaneous closure of groin sites with ProGlide
devices.
Common Complications
Key Point
Pearls to minimize post-procedural complications:
1. Identify and evaluate site of access to decide on
need for open or endovascular conduits.
2. Always ensure adequate anticoagulation during the
procedure to prevent thrombotic events.
3. Always maintain wire access with good wire
-
hygiene during catheter or wire exchanges. This
can avoid unnecessary radiation and contrast use.
4. Have different sizes available in case of unforeseen
events that will require additional pieces.
5. Always check distal pulses at the end of the case.
divider.
(d) Position the iliac limb into the aortic main
body graft with deployment extending just
proximal to the internal iliac artery.
(e) Complete deployment of aortic main body
graft and ipsilateral iliac limb. This limb is
often short of the internal iliac artery.
Sometimes the internal iliac artery will be
intentionally covered to ensure adequate seal.
(f)
limb with retrograde arteriogram to identify
iliac bifurcation. Determine length of iliac
limb extension for appropriate overlap and distal seal while preserving the hypogastric artery.
10. Device deployment TEVAR:
(a)Device planning often includes multiple-sized
devices and sometimes tapered devices.
Careful planning to deliver multiple devices is
Access
Compared to open surgical repair, endovascular approaches
are associated with high technical success with lower complication rates. The majority of early complications result
from access-related issues including hematoma, pseudoaneurysm or arteriovenous stula formation, thrombosis, and dissection. Atherosclerotic vessels cannot tolerate the driving
force of these large sheaths, which can cause signicant vessel trauma and rupture. Severely diseased iliac and femoral
arteries may require adjunctive interventions such as angioplasty, stenting, or endovascular or surgical graft conduits to
allow safe passage of larger bore sheaths. Radial expanding
sheaths can also be used in undersized iliac artery to prevent
iliac artery trauma. Based on preoperative imaging, these
interventions can be anticipated and planned ahead.
Access-related bleeding can also present in a delayed
fashion and lead to hemorrhagic shock from retroperitoneal
hemorrhage. This can be mitigated by accessing at the level
of the femoral head so that appropriate pressure can be held
17 Abdominal andThoracic Aortic Aneurysms
205
following the procedure. From a systematic review, accessrelated complications occurred in 4.4% of patients, a rate
that was signicantly lower compared with open femoral
access (relative risk [RR] 0.47, 95% CI 0.28–0.78) [55]. This
emphasizes the importance of preoperative planning and
appropriate patient selection.
Endoleaks (Refer toChap. 19 forMore
Information)
Endoleaks occur when there is persistent blood ow into the
aneurysmal sac despite endovascular coverage.
Contrast Nephropathy
Renal complications after TAA and AAA repair have been
linked to increased patient morbidity and mortality. Prior to
any intervention whether open or endovascular, it is important to identify those patients at risk by assessing preoperative renal function. Although clinical utility remains unclear,
it still remains common practice to be conservative in patients
with borderline renal function or a preoperative GFR<60mL/
min/1.73m
2
. Home medications that can be nephrotoxic or
vasoconstrictive should be held preoperatively. These
patients can be treated with hydration, bicarbonate infusion,
and/or Mucomyst prior to their procedure for renal protection. Overall contrast volume should be minimized and isoosmolar contrast agents can be utilized [56]. Further studies
noted that deterioration of renal function was independently
associated with age >70years in all patients (RR 2.92) during long-term follow-up of 23.2months [57]. Retrospective
studies have shown that renal complications were strongly
associated with 30-day mortality [58].
Spinal Cord Ischemia
This complication is almost exclusively associated with
TEVAR rather than EVAR.Although both open and endovascular thoracic aneurysm repair exhibit a risk for spinal
cord ischemia, studies have demonstrated lower rates with
TEVAR.Across the literature, rates of spinal cord ischemia
following thoracic aortic surgery have been reported to be
as high as 29% but average 10–11% [59]. In the perioperative setting, the spinal cord is extremely sensitive to uctuations in blood pressure. Any decreases in blood pressure can
affect perfusion to the spinal and intercostal arteries because
of graft coverage, ligation, or embolization. Additional risk
factors include advanced age, aortic rupture, prior aortic
surgery, postoperative bleeding, intraoperative hypotension,
and renal insufciency [60, 61]. To mitigate this risk, placement of somatosensory evoked potential monitoring and a
lumbar drain allow for perioperative monitoring and
increased spinal cord perfusion. During TEVAR, the extent
of aortic coverage is the major risk factor for spinal cord
ischemia. Interventions directed at increasing spinal cord
perfusion by increasing systemic blood pressure and
decreasing CSF pressure were effective for the reversal of
delayed onset of paraplegia after thoracic aneurysm repair,
resulting in an overall 3% incidence of permanent paraplegia and 3% incidence of residual paraparesis for endovascular cases [62].
Postoperative Monitoring
Following uncomplicated endovascular repair, patients are
frequently discharged after 24h. Fluids are typically continued to counter contrast nephropathy. Diets can be safely
resumed and advanced as tolerated. Peripheral pulses are
checked throughout the hospital course to evaluate for distal
perfusion. Routine postoperative surveillance is important to
both monitor the graft as well as the excluded aneurysmal
sac. A multiphase CTA is performed at 1month to evaluate
for endoleak or other device- related complications.
Depending on the imaging results, subsequent intervention
or additional follow- up surveillance imaging can then be
arranged. Imaging follow-up is provider specic but frequently performed at 1, 3, 6, and 12months post-procedurally followed by annually thereafter. To minimize costs,
aortic ultrasound is an acceptable replacement for CTA but is
highly technician dependent. It is important for patients to
continue their antiplatelet and statin medications as part of
their regimen to promote cardiovascular health.
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