Conditions of the Aorta and it`s branches

Dilation of the Aorta
and its Major Branches:
The Incidental and
Beyond
Shawn Sarin, MD, MBA
Director, Vascular and Interventional Radiology
The George Washington University Medical Center
Disclosures
• No Industry related
disclosures
• (unfortunately)
• Some of the devices
mentioned are “off
label”
• (way off label)
Objectives
• Anatomy, imaging,
lesions, treatment
options for:
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Aortic Root
Thoracic Aorta
Abdominal Aorta
Celiac axis
Splenic artery
Renal arteries
Iliac arteries
Outline
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Imaging
Thoracic Aorta
Abdominal Aorta
Branches of the Aorta
The Aorta
• Ultimate conduit
• Carries 200 million
liters during a life time
• Plays a role in control
of systemic vascular
resistance and heart
rate
• pressure receptors
located in the ascending
aorta and arch
2014 ESC Guidelines on the diagnosis and treatment of aortic diseases
European Heart Journal (2014) 35, 2873–2926 doi:10.1093/eurheartj/ehu281
The Aorta
• Diameter generally doesn’t exceed 40mm
• Tapers down stream
• Diameter influenced by:
• Age
• Gender
• Body size (BSA)
• BP
• Rate of expansion:
• males – 0.9mm/decade
• females – 0.7mm/decade
• Progressive dilation in mid-late life:
• ageing?
• higher collagen/elastin ratio
• increased stiffness
• increased pulse pressure
Imaging
• Complex structure, no imaging modality has perfect resolution
• ECG gating allows precise depiction of the aortic walls
• Standardized measurements essential:
• better assess changes in aortic size over time
• avoid erroneous findings of arterial growth
• similar determination of edges
• inner to inner
• outer to outer
• leading edge to leading edge
• systole vs. diastole?
• uncertain
• diastole gives best reproducibility
Imaging
• Maximum aneurysm
diameter
• perpendicular to the
centerline of the
vessel
• 3D reconstruction
whenever possible
2014 ESC Guidelines on the diagnosis and treatment of aortic diseases
European Heart Journal (2014) 35, 2873–2926 doi:10.1093/eurheartj/ehu281
Chest X-Ray
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Obtained for other indications generally
May detect abnormal contour/size – incidental finding
Limited value for detecting an ascending aortic aneurysm
normal aortic silhouette is not sufficient to rule out the
presence of an aneurysm
Transthoracic echocardiography
• Not the technique of choice for full assessment of the aorta
• Excellent imaging modality for:
• serial measurement of maximal aortic root diameters (TTE)
• assessment for AR (TTE)
• Can suffice for:
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screening test for TAA (TTE)
arch pathology, aneurysm, dissection, plaque
coarctation
PDA
Transoesophageal
echocardiography
• Proximity allows for higher resolution images
• Allows for imaging of the aorta from its root to the descending
aorta
• Semi invasive:
• requires sedation
• strict blood pressure control
• exclusion of esophageal diseases
• Blind spot:
• distal ascending aorta – interposition of trachea and right main
stem bronchus
Abdominal ultrasound
• Mainstay of abdominal aortic disease imaging:
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accurate aortic measurement
detect wall lesions (plaque, thrombus, etc)
widely available
non invasive
contrast enhanced and duplex – additional information on aortic
flow
• endoleaks
• dissection flaps
• Less accurate with tortuous AAA
• Less reproducible measurements
• inter observer variance can be 1.9mm to 10.5mm
• .5mm is considered acceptable
Computed Tomography
• Central role in the diagnosis, risk stratification, and management of
aortic diseases
• Advantages:
• quickly obtains 3D data set of entire aorta
• widely available
• ECG protocols nearly eliminate motion artifact (aortic root, ascending
aorta)
• can evaluate for IMH and dissection
• simultaneous coronary CTA can evaluate/exclude CAD
• Disadvantages:
• contrast
• radiation
• 10-15 mSv
• women>men
• plateau after 50
Computed Tomography
Einstein AJ, Weiner SD, Bernheim A, Kulon M, Bokhari S, Johnson LL, Moses JW, Balter S. Multiple testing, cumulative radiation
dose, and clinical indications in patients undergoing myocardial perfusion imaging. JAMA 2010;304:2137 – 2144.
Positron emission
tomography/computed
tomography
• Aortic involvement
with inflammatory
vascular disease (e.g.
Takayasu arteritis,
GCA),
• Endovascular graft
infection,
• Track inflammatory
activity over a given
period of treatment
Basu S, Kumar R, Alavi A. PET and PET-CT imaging in infection and inflammation: Its critical role in
assessing complications related to therapeutic interventions in patients with cancer. Indian J Cancer
2010;47:371-9
Magnetic Resonance Imaging
• Reliably depicts:
• maximal aortic diameter
• shape and extent of the aorta
• involvement of aortic branches in aneurysmal dilation or dissection
• relationship to adjacent structures
• presence of mural thrombus
• Good for:
• serial follow up, younger patients, no radiation
• gadolinium contrast likely less nephrotoxic (limited use with low GFR)
• Bad for:
• acute setting
• less widely available, can’t monitor unstable patients, long acquisition
times
Aortography
• Provides:
• exact information about the shape and size of the aorta, as well
as any anomalies
• temporal evaluation of blood flow
• Drawbacks
• invasive
• contrast and radiation drawbacks
• misses diseases of the aortic wall
• Generally only performed during repair
• sometimes reserved for complex cases
• if needed coronary, LV function or aortic branches can be
evaluated in conjuction
Comparison of imaging methods
2014 ESC Guidelines on the diagnosis and treatment of aortic diseases
European Heart Journal (2014) 35, 2873–2926 doi:10.1093/eurheartj/ehu281
Thoracic Aorta
Aortic Root - Anatomy
• anatomic segment
between the left
ventricle and the
ascending aorta
• components function
as a unit:
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aortic annulus
aortic cusps
aortic sinuses
sinotubular junction
Aortic Root - Angiogram
J Am Coll Cardiol Intv. 2010;3(1):105-113. doi:10.1016/j.jcin.2009.10.014
Aortic Root - TTE
Isselbacher E M Circulation. 2005;111:816-828
Aortic Root - TEE
http://echocardiographer.org/
Aortic Root - CT
J Am Coll Cardiol Img. 2008;1(3):321-330. doi:10.1016/j.jcmg.2007.12.006
Aortic Root - MR
Burman E D et al. Circ Cardiovasc Imaging. 2008;1:104-113
Ascending Aorta - Anatomy
• Begins at the aortic
valve and terminates
at the right
brachiocepahlic
Ascending Aorta - Anatomy
• right/left coronaries
• right/left sinuses of
Valsalva
• tubular configuration
gained at sinotubular
junction
courtesy of Dr Frank Gaillard, Radiopaedia.org
Ascending Aorta - Imaging
• CT
• MR
• Echo (TEE)
• blind spot – distal
ascending
• Angiography
Aortic Arch - Anatomy
• Continuation of the
ascending aorta
• starting at the level of
the sternomanubrial
joint
• Three branches:
• right brachiocephalic
• left common carotid
• left subclavain
• Variants common
• Additional vessels can
arise from arch
• left vertebral
• thyroidea ima
courtesy of Dr Frank Gaillard, Radiopaedia.org
Aortic Arch - Anatomy
courtesy of Dr Frank Gaillard, Radiopaedia.org
Aortic Arch - Imaging
• CT
• MR
• Echo (TEE)
• Angiography
Descending Aorta - Anatomy
• continuation of the
aortic arch
• commences at the
level of the fourth
thoracic vertebra body.
It continues as
the abdominal aorta at
the aortic
diaphragmatic
hiatus at the level of
the twelfth thoracic
vertebra
Descending - Imaging
• CT
• MR
• Echo (TEE)
• Angiography
Normal Thoracic Vessel sizes
• Ascending Aorta:
• female: 3.6 cm
• male: 3.8 cm
• Proximal Descending Aorta:
• 2.6 cm
• Distal Descending Aorta:
• 2.4 cm
• Enlarged/Ectatic:
• ascending – 4 cm
• descending – 3 cm
• Aneurysmal:
• ascending – 5 cm
• descending – 4 cm
Aronberg DJ, Glazer HS, Madsen K, Sagel SS. Nor- mal thoracic aortic diameters by computed tomography. J Comput Assist Tomogr 1984;8:247–250.
Thoracic Aneurysm Rupture Risk
• Yale Center for Thoracic Aortic Disease – 9000 patient years of follow
up
• likelihood of rupture or dissection skyrockets:
• ascending - 5.5 cm
• descending - 6.5 cm
• yearly rate of rupture, dissection, or death is 14.1% for a patient
with a thoracic aorta of 6 cm diameter
• elective intervention prevents most adverse events:
• ascending – 5 cm
• descending – 6 cm
• symptomatic aneurysms require intervention at any size
Curr Probl Cardiol. 2008 May;33(5):203-77. doi: 10.1016/j.cpcardiol.2008.01.004.
Thoracic aortic aneurysm: reading the enemy's playbook.
Elefteriades JA.
2010 ACCF/AHA guidelines for
thoracic aortic disease
Ratio likely more accurate
Natural History of Conservative
Management
• 4-5 cm - observation
with annual CT/echo
• 5-5.5 cm – medical
therapy and biannual
or annual imaging
Bentall Procedure
• replacing the
ascending aorta and
the aortic valve
• bovine or porcine
valve
aortarepair.com
Valve Sparing Root Replacement
• Yacoub and David
procedures
• aortic valve is
reimplanted into the
prosthetic tube graft
• failure rate (valvesparing aortic root
operations) ~ 10% in
20 years
aortarepair.com
Endovascular Repair - Thoracic
sirctsurgery.com
Hybrid Repair - Thoracic
Type II arch hybrid debranching procedure
Prashanth Vallabhajosyula, Wilson Y. Szeto, Nimesh Desai, Caroline Komlo, Joseph E. Bavaria
Ann Cardiothorac Surg 2013;2(3):378-386
The Last Frontier?
Abdominal Aorta
Introduction
• >3cm = AAA
• AAA – exact cause not known
• 20% Familial
• 90% Degenerative
Incidence
• Prevalence
• 4.2-8.8% Men
• 0.6-1.4% Women
• 5x Male>Female
• 3.5x Caucasian Male > African American Male
• Process appears to begin in men at 50 peaks at
80
• Rupture – 4.4 cases per 100,000
Lederle FA, Johnson GR, Wilson SE, Chute EP, Littooy FN, Bandyk D. Prevalence and associations of abdominal aortic aneurysm detected through screening. Aneurysm Detection and Management (ADAM) Veterans Affairs Cooperative Study Group. Ann Intern Med. Mar 15 1997;126(6):4419.
Etiology
• Degenerative Process?
• Related to Atherosclerosis?
• 20% Familial
• Majumder – single dominant gene
• Tilson – Autoimmune process – DRB1
Majumder PP, St Jean PL, Ferrell RE, Webster MW, Steed DL. On the inheritance of abdominal aortic aneurysm. Am J Hum Genet. Jan 1991;48(1):164-70.
Tilson MD, Ozsvath KJ, Hirose H, Xia S. A genetic basis for autoimmune manifestations in the abdominal aortic aneurysm resides in the MHC class II locus DR-beta-1. Ann N Y Acad Sci. Nov 18 1996;800:208-15.
Etiology
• Other Causes:
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Infection
Cystic medial necrosis
Arteritis
Trauma
Connective tissue disorders
Pseudoanuerysms / Anastomotic Disruption
Etiology
• Risk Factors
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Smoking
Hypertension
Age (peak incidence 70-80)
Familial history (15-25%)
Caucasian
Male (5x)
SAAAVE Act
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“Screening Abdominal Aortic Aneurysms Very Efficiently”
Became law 2/2006, effective 1/1/2007
Free one time screening ultrasound
Who qualifies?
• Men who smoked at least 100 cigarettes
• Men and women with family history
Clinical Features
• Most are asymptomatic
• Nonspecific signs/symptoms
• Pain (with expansion)
• Deep, visceral pain – lumbosacral region
• Abnormally prominent abdominal pulsation
• Tenderness
Diagnosis
• Diagnosis / Imaging tests:
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Ultrasound
CT
MR
Angiogram
Treatment
• Repair of aneurysms <5 cm – no survival benefit
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Follow with US, CT → 6-12 months
Control atherosclerotic risk factors
Smoking cessation
Control HTN
Treatment
• Elective repair > 5cm
• Additional indications:
• Increase in size >0.5cm within 6 months
• Chronic pain
• Thromboembolic complications – mural thrombus → feet, bowel
• Before repair – screen and treat CAD
Treatment
• Some AAA’s enlarge at a steady rate of 2-3mm/year, some
faster
• About 20% remain the same size indefinitely
• Need for treatment is related to size – which is linked to
rupture
Abdominal Aortic Aneurysm Size and
Rupture Risk
AAA Diameter (cm)
Rupture Risk (%/yr)
<4
0
6–6.9
10–20%
4–4.9
1%
7–7.9
20–40%
5–5.9*
>8
5–10%
30–50%
*Elective surgical repair should be considered for aneurysms > 5.0–5.5 cm
Treatment
• Tailored for each patient
• Aneurysm size
• Patient Age
• Co-morbidities
• Surgery
• Endovascular repair
Endovascular
Aneurysm Repair
(EVAR)
Follow Up
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CTA 1, 6, 12 months post op, then annually
May follow with US if stable
Abdominal Xray
Main features to monitor
• AAA size, integrity of graft, endoleaks, sac expansion, device
migration
Results for EVAR
• DREAM trial
• Compared EVAR to open repair
• 345 patients with AAA’s >5cm who were eligible for
both EVAR and open repair were randomized
• EVAR
• much lower operative mortality (1.2% vs. 4.6%)
• Less severe complications (4.7% vs. 9.8%)
• European registries have reported higher annual
failure rates for EVAR (3% vs .3%)
J Cardiovasc Surg (Torino). 2002 Jun;43(3):379-84
Endoleaks
Type I - related to device
attachment
Type II – retrograde flow from
collateral branches
Type III – Fabric tears, graft
disconnection, disintegration
Type IV – Flow through graft wall
“porosity”
Type V - Endotension – persistent
pressurization of the sac with no
evidence of endoleak
Visceral Aneurysms