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B. R. Imielski and L. N. Girardi
• Careful patient selection is paramount, as these cases are reserved for poor surgi-
cal candidates and have higher incidences of stroke, paralysis, dissection, and
other adverse outcomes.
• There are ongoing clinical trials investigating TEVAR deployment across the
arch with fenestrated and branched grafts into the great vessels in high-risk
patients. These include the NEXUS aortic arch (TRIOMPHE) (NCT02365454),
the endovascular treatment of TAAA and aortic arch aneurysms using fenestrated and branched grafts (NCT02323581), and the early feasibility of the
branched TAG device in the treatment of aortic arch aneurysms studies
(NCT02264977).
References
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LK, Isselbacher EM, Kazerooni EA, Kouchoukos NT, Lytle BW, Milewicz DM, Reich DL,
Sen S, Shinn JA, Svensson LG, Williams DM, American College of Cardiology Foundation/
American Heart Association Task Force on Practice Guidelines, American Association for
Thoracic Surgery, American College of Radiology, American Stroke Association, Society of
Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions,
Society of Interventional Radiology, Society of Thoracic Surgeons, Society for Vascular
Medicine. 2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the
diagnosis and management of patients with thoracic aortic disease: a report of the American
College of Cardiology Foundation/American Heart Association Task Force on Practice
Guidelines, American Association for Thoracic Surgery, American College of Radiology,
American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for
Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of
Thoracic Surgeons, and Society for Vascular Medicine. Circulation. 2010;121(13):e266–369.
https://doi.org/10.1161/CIR.0b013e3181d4739e. Epub 2010 Mar 16. Erratum in: Circulation.
2010 Jul 27;122(4):e410.
2. Otto CM, Nishimura RA, Bonow RO, Carabello BA, Erwin JP 3rd, Gentile F, Jneid H, Krieger
EV, Mack M, McLeod C, O’Gara PT, Rigolin VH, Sundt TM 3rd, Thompson A, Toly C. 2020
ACC/AHA guideline for the management of patients with valvular heart disease: executive
summary: a report of the American College of Cardiology/American Heart Association Joint
Committee on Clinical Practice Guidelines. Circulation. 2021;143(5):e35–71. https://doi.
org/10.1161/CIR.0000000000000932. Epub 2020 Dec 17. Erratum in: Circulation. 2021 Feb
2;143(5):e228. Erratum in: Circulation. 2021 Mar 9;143(10):e784.
3. Girardi LN, DeAnda A Jr, Ikonomidis JS. Feature editor summary: highlighting invited
expert opinions on aortic subjects. J Thorac Cardiovasc Surg. 2021;162(1):40–3. https://doi.
org/10.1016/j.jtcvs.2021.04.046. Epub 2021 Apr 22.
4. Lau C, Gaudino M, de Biasi AR, Munjal M, Girardi LN. Outcomes of open repair of
mycotic descending thoracic and thoracoabdominal aortic aneurysms. Ann Thorac Surg.
2015;100(5):1712–7. https://doi.org/10.1016/j.athoracsur.2015.05.067. Epub 2015 Aug 13.
5. Lau C, Gaudino M, Iannacone EM, Gambardella I, Munjal M, Ohmes LB, Degner BC,
Girardi LN.Retrograde cerebral perfusion is effective for prolonged circulatory arrest in arch
aneurysm repair. Ann Thorac Surg. 2018;105(2):491–7. https://doi.org/10.1016/j.athorac-
sur.2017.07.018. Epub 2017 Nov 1.
19 Aneurysmal Disease oftheAscending Aorta, Root, andArch
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6. Kuzmik GA, Sang AX, Elefteriades JA.Natural history of thoracic aortic aneurysms. J Vasc
Surg. 2012;56(2):565–71. https://doi.org/10.1016/j.jvs.2012.04.053.
7. Brinster DR, Rizzo RJ, Bolman RM.Ascending aortic aneurysms. In: Cohn LH, editor. Cardiac
surgery in the adult. NewYork: McGraw-Hill Medical; 2008. p.1223–50.
8. Spielvogel D, Mathur MN, Griepp RB.Aneurysms of the aortic arch. In: Cogn LH, editor.
Cardiac surgery in the adult. NewYork: McGraw-Hill Medical; 2008. p.1251–76.
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Chapter 20
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Descending Thoracic
andThoracoabdominal Aortic Aneurysms
SrihariK.Lella andArminderS.Jassar
Anatomy, Denition, andEtiology
• Aneurysms are localized dilations resulting from weakening of the arterial wall
and consequent expansion in the vessel size. Generally, a dilation to 1.5 times the
normal arterial diameter is dened as an aneurysm.
• Descending thoracic aortic aneurysms (DTAAs) are localized to the descending
thoracic aorta while thoracoabdominal aortic aneurysms (TAAAs) can extend
variably from distal to the left subclavian artery to the aorto-iliac bifurcation.
• TAAAs are classied according to the Crawford/Sa classication (Fig.20.1):
– Type I: distal to left subclavian artery → suprarenal abdominal aorta
– Type II: distal to left subclavian artery → infrarenal aorta
– Type III: distal to T6 → infrarenal aorta
– Type IV: distal to diaphragm → infrarenal aorta
– Type V: distal to T6 → suprarenal abdominal aorta
• DTAAs and TAAAs can result either due to the medial degeneration of the aortic
wall due to atherosclerosis or due to aortic degeneration after acute aortic
dissection.
S. K. Lella (*)
Division of Vascular and Endovascular Surgery, Department of Surgery, Massachusetts
General Hospital, Boston, MA, USA
e-mail: srihari.lella@mgh.harvard.edu
A. S. Jassar
Division of Cardiac Surgery, Department of Surgery, Massachusetts General Hospital,
Boston, MA, USA
e-mail: AJASSAR@mgh.harvard.edu
Switzerland AG 2024
J. P. Bloom, T. M. Sundt (eds.), Cardiac Surgery Clerkship, Contemporary
Surgical Clerkships, https://doi.org/10.1007/978-3-031-41301-8_20
227© The Author(s), under exclusive license to Springer Nature
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S. K. Lella and A. S. Jassar
Fig. 20.1 Crawford/Sa classication of thoracoabdominal aortic aneurysms
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• Autoimmune disorders, such as giant cell arteritis or Takayasu’s arteritis, con-
nective tissue disorders (e.g., Marfan’s syndrome, Ehlers-Danlos syndrome),
infection, and aortic anomalies can also result in aneurysms.
229
History andPhysical
• Majority of patients do not have symptoms associated with their aneurysms,
which are often found incidentally.
• When symptomatic, vague pain involving the chest, abdomen, and/or back/ank
is the most common complaint. Pain is an important sign in the setting of aortic
aneurysms and may be a harbinger of impending rupture.
• Other symptoms can result from local mechanical effects on nearby structures:
– Cough or other respiratory symptoms from tracheal deviation.
– Dysphagia from esophageal compression.
– Hoarseness from recurrent laryngeal nerve compression or stretching.
• Although rare, erosion of the aneurysm into the esophagus or the airway can
result in hematemesis/hemoptysis.
• Large aneurysms can sometimes be palpated as a prominent impulse on abdomi-
nal exam, especially in thin patients.
• Evaluate for tracheal deviation, abdominal tenderness, or diminished pulses in
the lower extremities.
• Acute dissection or rupture of an aortic aneurysm can present as sudden onset of
sharp severe pain, which may localize to the chest, abdomen or the back.
Malperfusion to the viscera, kidneys, and lower extremities can also occur from
embolization or dissection.
Tests
Imaging Evaluation
• Computed tomographic angiography (CTA)
– Most used non-invasive imaging modality in dening aortic pathology.
– Valuable in evaluating etiology (e.g., complex dissection vs. primary degen-
erative disease) and anatomy (e.g., branch vessels, large intercostals, and signicant plaque/calcication) as well as planning surgical repair.
– Requires intravenous iodinated contrast, which may be restrictive in patients
who are allergic to contrast or those with signicant renal impairment.
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• Magnetic resonance angiography
– Can provide similar information as CTA with regards to aortic pathology but
has lower spatial resolution.
– Newer 4D MRI offers the ability to assess ow dynamics may assist in iden-
tifying particularly weak spots in the aneurysmal wall.
– Longer study times.
– Difcult to obtain in claustrophobic patients without pre-medication.
– Contraindicated in patients with signicant metal implants (e.g., certain
pacemakers).
– Costly and less readily available.
• Ultrasound
– Historically used as primary diagnostic modality for aortic aneurysms but it
has now been largely replaced by axial imaging.
– Today, used for monitoring of smaller sized abdominal aortic aneurysms until
the size approaches closer to repair, at which time higher spatial resolution
imaging is sought.
– Limitations:
Ultrasound technologist variability.
Vision obstructed by bowel gas and osseous structures.
Has shown to underestimate diameters (~5 mm) in the anterioposterior
direction as compared to CT, with even less accuracy in the lateral direction.
S. K. Lella and A. S. Jassar
• Positron emission tomography—computed tomography (PET/CT)
– To assess for inammatory causes of aneurysms (e.g., aortitis).
– Helpful in assessing active and inactive vasculitis.
– Can also be used to detect infectious aortitis, including response to antibiotic
therapy.
– Limited spatial resolution.
• Tagged white blood cell scan
– Nuclear imaging study, which similarly to PET/CT, can be used to assess for
inamed/infected aneurysms.
Labs
• When less common etiologies are suspected, certain labs and/or markers can be
checked to assess for autoimmune or genetic causes, e.g., elevated ESR, CRP, or
IgG4 levels may indicate presence of acute aortitis.
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231
Management andTreatment
• No medical treatment currently exists that causes shrinkage or reduction in the
size of aortic aneurysms.
• Indications for repair:
– Aortic diameter is primarily used to determine the need for repair given that
the risk of rupture increases with increasing size (i.e., Laplace’s Law).
Current recommended size threshold for aneurysm repair generally ranges
from 5 to 6cm based on aneurysm anatomy, suitability for endovascular
repair, and patient’s overall health.
Consider repair at smaller diameters in patients with connective tissue disorders (e.g., Marfan syndrome, Loeys-Dietz syndrome, Ehler-Danlos
syndrome).
Patient comorbidities, body surface area, aneurysm etiology, and morphology can be taken into consideration while determining the timing of aortic
repair (e.g., a generally healthy patient with an aneurysm that require a
simple repair and with low risk may be considered for repair earlier compared to an extensive aneurysm in a high-risk patient who might be
expected to have increased risk of complications from their procedure).
– ≥5mm/6months rate of growth of the aneurysm, regardless of aneurysm size.
– Symptomatic patients should also be considered for repair, irrespective of
aneurysm diameter.
• Patients who do not meet criteria for repair at their initial diagnosis should
undergo periodic monitoring with surveillance imaging.
• Medical management and risk factor modication
– Strict blood pressure management (beta blocker and/or angiotensin- converting
enzyme inhibitor or angiotensin receptor blockers).
– Atherosclerotic risk-reduction (statins).
– Smoking cessation.
– Avoidance of heavy, strenuous activities.
• Adjuvant treatments may be necessary for certain aneurysm etiologies:
– Mycotic aneurysms, which generally warrant repair regardless of the size,
require treatment with long-term antibiotics and possibly lifelong suppressive
antibiotics.
– Aneurysms secondary to vasculitis are often found during the acute inam-
matory phase, which may necessitate anti-inammatory medications (e.g.,
corticosteroids). Surgical repair can be delayed until resolution of the acute
phase, if possible.
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S. K. Lella and A. S. Jassar
Operative Repair: Open vs. Endovascular
• Repair is performed to reduce or eliminate the risk of rupture associated with
aneurysms.
• Open surgical repair consists of a left thoracotomy (for DTAAs) or left thoracoabdominal (for TAAAs) incision for replacement of the affected aortic segment
with an articial graft. In cases of infection, cryopreserved allografts or pericardial tubes can be utilized in lieu of synthetic grafts.
• If the involved segment involves any major aortic branches (celiac, superior mesenteric artery, renal arteries), these are detached from the aorta and reimplanted
on to the aortic graft (described in detail below).
• Endovascular repair utilizes cylindrical endografts to create a neo-lumen with
restriction of blood ow into the aneurysm sac
– Thoracic endovascular aortic repair (TEVAR) has become the mainstay of
therapy for DTAA.
– There are currently no commercially available endografts for TAAA repair in
the US. Physician-modied stent grafts for endovascular repair of TAAA
require a main body for the aortic portion, with additional branches to maintain perfusion of the reno-visceral vessels. Investigator device exemption trials involving fenestrated and branched stent graft systems are being conducted
with potential market availability in the near future. As such, open repair
remains the current mainstay of therapy for TAAA.
• Hybrid approach to repair can also be performed for TAAAs, which involves
open visceral debranching followed for endovascular aortic stent grafting.
Endovascular Repair ofDTAA (TEVAR)
Preoperative planning
• Requires careful assessment of imaging to study aneurysm, branch vessel (i.e.,
arch and visceral vessels), and access vessel (i.e., iliofemorals) morphology
(e.g., tortuosity) and quality (e.g., presence of thrombus, calcications).
• Assessment of anticipated proximal and distal landing zones (areas of nonaneurysmal aorta on either side of the aneurysm). Generally, at least 2cm of
landing zone in normal aorta is desirable to allow for endograft to aorta apposition (“seal”).
– Proximally, if coverage of the left subclavian artery is necessary to form a
seal, then preoperative revascularization via a left subclavian-carotid bypass
or transposition can be performed.
– Distally, when celiac artery coverage is necessary, celiac artery/superior mes-
enteric artery collaterals should be carefully ascertained to determine the need
for celiac artery revascularization.
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233
• Using 3D imaging software, the aorta should be sized (i.e., vessel diameter and
length of coverage) orthogonal to the line of blood ow.
• If access vessels are of insufcient size to accommodate the sheaths, a plan for
conduits (either endovascular or open) should be determined.
Operative Repair
TEVAR (Fig.20.2) with the proximal landing zone just distal to the left subclavian
artery and the distal landing zone just proximal to the celiac artery is described.
Fig. 20.2 Before and after
computed tomographic
angiography scan (bottom
images) and 3D rendering
(top images) of a patient
with a TAAA who
underwent TEVAR rst
stage procedure before
repair of the TAAA
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S. K. Lella and A. S. Jassar
• Before initiation of anesthesia, a prophylactic cerebrospinal uid drainage catheter can be considered. As cerebral perfusion pressure (CPP) is dened by the
difference between the mean arterial pressure (MAP) and intracranial pressure
(ICP), drainage results in a decrease of the ICP (CPP=MAP − ICP). Generally,
a CPP~70mmHg or higher is maintained.
• The patient is placed in the supine position and bilateral groins are prepped and
draped in a sterile fashion.
• Access to the femoral vessels can be obtained either via a surgical cutdown to
expose the common femoral artery or percutaneously using ultrasound guidance.
Side of graft deployment (usually termed ipsilateral side) is selected based on
iliofemoral vessel size (usually need ≥6–7mm, based on the diameter of the
selected stent graft) and anatomy (calcication, tortuosity, etc.). Percutaneous
access is obtained on the contralateral side for imaging purposes. Using Seldinger
technique, vascular sheaths are placed to maintain vascular access throughout
the procedure. A soft wire is inserted into the aorta from the ipsilateral side and
advanced proximal to intended proximal landing zone. This is then exchanged
over a catheter to a stiff wire, which will be used to guide the stent graft for insertion. A pigtail catheter with radio-opaque markings is inserted on the contralateral side for imaging.
• Angiography is performed via the pigtail catheter for visualization of the landing
zones and nal graft sizing. The radio-opaque markers on the pigtail are used to
determine the length of the stent graft that is required to completely cover the
aneurysm. More than one stent graft can be used depending on the diameter of
the proximal and distal landing zones and the length of the aorta that needs to be
covered.
• The appropriate diameter stent graft (usually 15–20% larger than the aortic
diameter in the area of the landing zone) is advanced over the stiff wire to the
target location.
• Deployment is device specic, and instructions from manufacturer should be
followed; this step should be fully performed under live uoroscopic visualization. Blood pressure should be controlled (decreased to MAP ~60) during this
step to reduce the risk of misplacement due to windsocking effect. Additional
stent grafts are deployed ensuring adequate overlap (usually ≥5cm) with the
preceding stent grafts, until the distal stent portion of the stent graft reaches the
intended distal landing zone.
• After stent graft deployment, completion angiography is performed to ensure for
accurate placement with no evidence of endoleaks. Certain endoleaks can be
watched while others (Type I/III) must be treated at the time of the procedure.
• The vascular sheaths are removed, and the arterial access sites are repaired,
either with direct repair in case of surgical cutdown, or using one of several commercially available percutaneous vessel closure devices for cases where vessel
was accessed percutaneously.
If the patient had a spinal drain placed and there is no evidence of spinal cord
ischemia, the drain can be removed on postoperative day 1. If, however, there is
evidence of spinal cord ischemia, spinal drain is maintained. Management of spinal
cord ischemia is further described below.
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