EMGuideWire's Radiology Reading Room: Aortic Dissection

Aortic Dissection Case Studies
Matthew Cravens, MD
Shelby Hixson, PA
Tyler Siekmann, MD
Department of Emergency Medicine
Carolinas Medical Center & Levine Children’s Hospital
Charlotte, North Carolina
Faculty Editors: Bryant Allen, MD & Michael Gibbs, MD
The Chest X-Ray Mastery Project™

Disclosures
This ongoing chest X-ray interpretation series is proudly sponsored by the
Emergency Medicine Residency Program at Carolinas Medical Center.
The goal is to promote widespread mastery of CXR interpretation.
There is no personal health information [PHI] within, and all ages have been
changed to protect patient confidentiality.

Process
Many are providing clinical cases, and presentations are shared with all
contributors on our departmental educational website.
Contributors from many Carolinas Medical Center departments, and now…
Brazil, Chile, and Tanzania.
We will review a series of CXR case studies and discuss an approach to the
diagnoses at hand: ACUTE AORTIC DISSECTION.

Visit our website
www.EMGuidewire.com
For a complete archive of chest x-ray presentations and much more!

Airway
Bones
Cardiac
Diaphragm
Effusion
Foreign body
Gastric
Hilum

CXR evaluation for aortic dissection centers on the mediastinum – focus on the
mediastinal width at the level of the aortic knob, and on the aortic contour.
Normal PA CXR

Aortic
Dissection“A man was seized with pain of the right arm
and soon after the left. He was ordered to
think seriously and piously of his departure
from this mortal life, which was very near at
hand and inevitable.”
J.B. Morgagni, 1761.
“There is no diagnosis more conducive to clinical
humility than dissection of the aorta.”
Sir William Osler, 1900.

Image credit 1: http://www.iradonline.org/about.html
Image credit 2: https://torontonotes.ca/cardiology-cvs-new/coloured-atlas-cardiology-cvs-new/gross-pathology/aortic-dissection/
What is aortic dissection?
Intima of the aorta tears & blood flows into media
Blood tracks proximally/distally, creating a false
lumen
A false lumen in the thoracic aorta can widen the
mediastinum
The intimal flap can occlude branches off the true
lumen -> end organ ischemia

Chest x-ray is often the first imaging study performed in patients with
clinical suspicion for non-traumatic aortic dissection.
While certainly not the gold standard imaging modality, several chest x-ray
findings can be helpful in raising suspicion for aortic dissection.
Our best data on aortic dissection imaging findings comes from a
prospective case series of 400+ patients enrolled in the late 1990’s.
This case series became the foundation for the International Registry of
Acute Aortic Dissections, a multinational research consortium also known
as IRAD.
IRAD data was first published in 2000 and updated in 2018.

IRAD 2000: Chest X-ray Findings
427 patients presenting with confirmed acute aortic dissection
CXR Findings:
Widened mediastinum 66.1%
Abnormal aortic contour 49.6%
Pleural effusion 19.2%
Wall Ca++
displacement 14.1%
Normal CXR 12.4%
Hagan PG. JAMA 2000.

Widened mediastinum was the most frequent IRAD finding
for acute aortic dissection
Classically defined as >6-8 cm at level of aortic knob on PA film
BUT many critically ill ED patients get portable CXRs, which are AP.
AP films artifactually widen the mediastinum!
Wall Ca++
displacement 14.1%
Normal CXR 12.4%
So what width should we use?
PA film (formal CXR): 6-8cm?
AP film (portable CXR): ??

AP film of a healthy patient:
mediastinum appears wide…
Same patient’s PA/formal film.
Image credit: Case courtesy of Dr Yi-Jin Kuok, Radiopaedia.org, rID: 17910

PA (formal) : 7.5 cm
Sens 90%, Spec 88%
AP (portable): 8.7 cm
Sens 72%, Spec 80%
Emerg Radiol 2012
• 2012 case series of 100 CXRs of patients with
acute aortic dissection and 120 controls
• PA films were more sensitive and specific,
and had lower cutoff for mediastinal width

Tips for evaluating the mediastinum on CXR
PA films should be preferred but are not always feasible.
Measure mediastinal width horizontally at the aortic knob.
The classic cutoff of 6-8 cm may require adjustments, especially for
AP/portable films.
Consider a cutoff of 7-8cm for PA and 8-9cm for AP films.
Always compare to prior, even if under cutoff!

CASES
Let’s move on to examples of real patients presenting to the
emergency department with non-traumatic acute aortic dissection.
Note whether the film is labeled AP (“Port”) or PA
Measurements are not included here

71-year-old from
Ghana with chest
pain.

Wide
Mediastinum
71-year-old from
Ghana with chest
pain.
Note that the normal smooth aortic knob contour is lost.

This same patient’s CT showing thoracic aortic aneurysm with Type A dissection
71-year-old from
Ghana with chest
pain.

41-year-old with
Marfan
syndrome.

Thoracic aortic aneurysm and chronic Type B dissection
Wide
Mediastinum
41-year-old with
Marfan
syndrome.

CT Scan demonstrating thoracic aortic aneurysm and chronic Type B dissection
41-year-old with
Marfan
syndrome.

69-year-old with
acute neck and
chest pain.

Wide
Mediastinum
69-year-old with
acute neck and
chest pain.

Dilated Aortic
Root
This patient’s ED bedside ultrasound
Aortic
Free Wall
69-year-old with
acute neck and
chest pain.

This patient’s CT demonstrating Type A aortic dissection
69-year-old with
acute neck and
chest pain.

Now for some more subtle examples…

During his ED
stay, the pain
migrates to his
abdomen…
51-year-old with
burning chest
pain for one hour
after a verbal
argument.

51-year-old with
burning chest
pain for one hour
after a verbal
argument.

Type A aortic dissection
51-year-old with burning chest pain for
1 hour after getting into an argument.

73-year-old with
HTN develops
acute chest pain
radiating to the
back.

Wide
Mediastinum
73-year-old with
HTN develops
acute chest pain
radiating to the
back.

This patient’s CT demonstrating Type A Dissection
73-year-old with
HTN develops
acute chest pain
radiating to the
back.

This patient’s ED bedside ultrasound
Dissection Flap
Thoracic
Aorta
73-year-old with
HTN develops
acute chest pain
radiating to the
back.

65-year-old man
with history of
HTN presents to
the ED with chest
pain.

Let’s introduce another CXR sign of dissection:
the Eggshell Sign
Many older patients have calcifications in the vessel intima
Blood in the media pushes the calcified intima inward
Eggshell sign: 5mm between wall Ca2+ & lateral border of aorta
Wall Ca
++
displacement 14.1%
Normal CXR 12.4%

Eggshell Sign
Eggshell Sign: Dissection pushes the calcified aortic wall inward

Eggshell Sign
Egg Shell Sign: The Dissection Pushes The Calcified Aortic Wall Inward.Eggshell Sign: Dissection pushes the calcified aortic wall inward

CASES
Just a few more cases! Look at the mediastinum, aortic
contour, and check for eggshell sign.

36-year-old with
acute chest and
back pain with leg
numbness.
Scout film of CT. CXR abnormalities?

Wide mediastinum
on CT scout film
36-year-old with
acute chest and
back pain with leg
numbness.

Type A dissection, from aortic root
to bilateral iliac arteries
36-year-old with
acute chest and
back pain with leg
numbness.

Today 1 Year Ago
36-year-old with poorly
controlled HTN presents
with 2 days of chest pain.
Note: both are PA films.

Today
Subtly
widened
mediastinum
on formal
measurement
Note: both are PA films.
1 Year Ago

False
Lumen
True
Lumen

55-year-old
woman with
HTN and chest
and abdominal
pain.

55-year-old
woman with
HTN and
chest and
abdominal
pain.

69-year-old male
with 5 days of
vague chest and
abdominal pain.

Eggshell Sign
Type B aortic dissection
69-year-old male
with 5 days of
vague chest and
abdominal pain.
Wide
Mediastinum

Type B aortic dissection
69-year-old male
with 5 days of
vague chest and
abdominal pain.

Today One Year Ago
44-year-old woman with HTN
presents with chest/back/abd pain.

Today One Year Ago
Type A Dissection
Wide
Mediastinum

Type A dissection

*
*
*
*
*
Type A dissection: hemopericardium

Aortic Dissection
That completes our cases! Now a brief
review of the literature.
• Classification: Stanford Type A and B
• Risk Factors
• Clinical presentation
• Organ ischemic complications
• Aortic valve/Pericardial complications
• Risk stratification tools

Stanford Type A
involves aortic arch

Stanford Type B
originates distal to left subclavian
artery

Risk Factors
• Hypertension is #1
• Cocaine
• Trauma
• Pregnancy
Iatrogenic
• Heart surgery
• Aortic valve repair
• Arterial catheterization
Congenital
• Aortic coarctation
• Bicuspid valve
• Marfan syndrome
• Ehlers-Danlos syndrome
• Turner syndrome

IRAD update, 2018:
Demographics, Risk Factors
Type A 67%
Type B 33%
Risk Factors
Hypertension 77%
Atherosclerosis 27%
Known aneurysm 16%
Cardiac surgery 16%
Marfan syndrome 5%
Iatrogenic 4%
Cocaine use1 2%
1Cocaine use 12% in black patients
66% of patients were male
The mean age was 63 years

IRAD 2000: Clinical Manifestations
Pain reported in 95.5%:
Chest pain 72.7%
Anterior chest pain 60.9%
Back pain 53.2%
Abdominal pain 29.6%

IRAD 2000: Clinical Manifestations
Quality of pain:
Abrupt onset 84.4%
‘Worst pain ever’ 90.6%
Sharp 64.4%
Tearing or ripping 50.6%
Radiating 28.3%
Migratory 16.6%

IRAD 2000: Syncope
Syncope in 9.4%
More common with Type A dissection
Higher risk of tamponade & stroke
Mortality
History of Syncope 34%
Overall 28%

IRAD update, 2018: Clinical Manifestations
Pain1 reported in 93.7%:
A B
Chest pain 79% 63%
Back pain 43% 64%
HPTN on presentation 36% 70%
Pulse deficit 30% 20%
Syncope2 19%
1,2Painless AAD and patients presenting with syncope had a
higher risk of heart failure, tamponade and death.
A = Type A Dissection
B = Type B Dissection

Chien N. Annals of EM 2018.
Chien 2018: Clinical Manifestations
Neuro deficit, pulse deficit, and hypotension were the most helpful
positive physical exam findings.

Branch Vessel Compromise
Organ Ischemia/Infarction

Artery Complication
Coronary Myocardial Infarction
Carotid Stroke
Radiculomedullary Spinal cord ischemia
Renal Renal failure
Subclavian/femoral Limb ischemia
Mesenteric Bowel ischemia

Chest Pain
Back Pain
Stroke symptoms
Paraplegia
Acute abdomen
Renal failure
Aortic
Dissection?
Paretic extremity

Aortic Valve Dysfunction, Hemopericardium
Aortic insufficiency
Acute pulmonary edema
Pericardial tamponade

Chest Pain
Back Pain
Acute CHF
New AI murmur
Syncope
Aortic
Dissection?

Loss of aortic contour + STEMI = Aortic Dissection?

Here’s the
problem…
We are NOT very
good at making the
diagnosis.
When we miss
the diagnosis,
patients die
We shouldn’t CTA every
patient with
chest/back/abdominal
pain.
Initial diagnosis correct 15-50%
Diagnosis >24 hours in 40%
Klompas M. JAMA 2002.

IRAD 2018 abstract:
Acute Aortic
Dissections are
challenging to
diagnose and treat
(even 20 years later)

To Summarize:
• Aortic dissection is a challenging diagnosis and is associated with high
morbidity and mortality
• Hypertension is by far the leading risk factor
• Most reliable historical features include sudden onset, severe pain to the
chest or back (although presentation symptoms vary widely)
• Most reliable PE findings include neurologic deficits, pulse deficits and
abnormal blood pressure at presentation. Other potential findings include
end-organ ischemia, aortic insufficiency, and tamponade.
Chest x-ray, while not perfect, can help us in evaluating for this diagnosis.

Comprehensive English language MEDLINE literature review from 1966 to 2000. Thirteen studies
permitted the analysis of 1337 chest X-rays.
 90% of patient with aortic dissection had at least one CXR abnormal finding
 The absence of a wide mediastinum had a [-] LR of 0.3 (95% CI: 0.2 – 0.4)

The absence of a wide mediastinum on CXR had a negative
likelihood ratio ranging from 0.14 to 0.60, making this a
finding that decreases the risk of aortic dissection
Evidence-based review of nine studies between 1986 and 2013, [n=2,400]
2018
Chien N. Annals of EM 2018.

How can we continue to improve our diagnostic accuracy
for acute aortic dissection?
In addition to mastering the interpretation of imaging
studies, new tools are currently being created such as:
• Clinical Decision Calculators
• Laboratory test adjuncts (i.e. D-dimer)

ADD-RS (Aortic dissection detection-risk score)
Rogers AM. Circulation 2011.
Score of 0 or 1 = low risk.
2 or 3 = high risk.
Only 1 point per category (e.g. new AI
murmur + pulse deficit = 1 point only)
Image from https://www.mdcalc.com/aortic-dissection-detection-risk-score-add-rs

Nazerian 2018, ADvISED Study
• Prospective multicenter trial, n=1850
• Investigated targeted use of D-dimer as a rule-out test in patients deemed
low risk by ADD-RS
• Negative D-dimer (<500) and ADD-RS of 0 or 1 (low-risk) ruled out Acute
Aortic Syndrome with a 0.3% failure rate
• Has not yet been externally validated – not currently recommended for use
• Of the 8 patients with Acute Aortic Syndrome with negative D-dimer, 2 had
widened mediastinum, 2 had no CXR (table on next slide)
Nazerian P. Circulation 2018.

Aortic
Dissection
• A challenging diagnosis currently lacking validated
rules for imaging
• HTN is the #1 risk factor
• Ischemia can involve every organ system
• Always look at the mediastinum and aortic
silhouette on your CXR!

THE PRESENT A ND FUTURE
J A CC REV IEW TOPIC O F THE W EEK
Optimal Treatment of Uncomplicated
Type B Aortic Dissection
JACC Review Topic of the W eek
Rami O. Tadros, MD,a
Gilbert H.L. Tang, MD, MSC, MBA,b
Hanna J. Barnes, BA,a
Idine Mousavi, BA,a
Jason C. Kovacic, MD, PHD,c
Peter Faries, MD,a
Jeffrey W. Olin, DO,c
Michael L. Marin, MD,a
David H. Adams, MDb
JACC JOURNAL CME/ MOC/ ECME
This article has been selected as the month’s JACC CME/MOC/ECME
activity, available online at http://www.acc.org/jacc-journals-cme by
selecting the JACC Journals CME/MOC/ECME tab.
Accreditation and Designation Statement
The American College of Cardiology Foundation (ACCF) is accredited by
the Accreditation Council for Continuing Medical Education to provide
continuing medical education for physicians.
The ACCF designates this Journal-based CME activity for a maximum
of 1AMA PRA Category 1Credit(s)Ô. Physicians should claim only the credit
2. Carefully read the CME/MOC/ECME-designat ed article available on-
line and in this issue of the Journal.
3. Answer the post-test questions. A passing score of at least 70% must be
achieved to obtain credit.
4. Complete a brief evaluation.
5. Claim your CME/MOC/ECME credit and receive your certificate
electronically by following the instructions given at the conclusion of
the activity.
J OU RN A L OF THE A MERI CA N CO L L EGE OF CA RDI OL OGY V OL . 7 4 , N O. 11, 2 0 19
ª 20 19 B Y THE A MERI CA N CO L L EGE OF CA RD I OL OGY FOUN D A TI O N
PUB L I SH ED B Y EL SEV I ER

If You Have Interesting Cases Of Acute Aortic Dissection, We Invite You
To Send A Set Of Digital PDF Images And A Brief Descriptive Clinical History To:
michael.gibbs@atriumhealth.org
Your De-Identified Case(s) Will Be Posted On Our Education Website And You
And Your Institution Will Be Recognized!

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