Aortic Dissection
Cardiovascular Emergencies and Shock
With Julianna Jung, MD, FACEP
Learning Objectives
By the end of this lecture, the learner will be able to:
• Describe the pathophysiology of aortic dissection.
• Identify appropriate diagnostic tests to evaluate for
aortic dissection.
• Differentiate between aortic dissection types.
• Describe the initial and definitive management for
aortic dissection.
Aortic Dissection Definition
Normal Dissection
Blood Intima Media Adventitia
Aortic Dissection is defined as
separation of the layers of the aortic wall and accumulation of blood between the layers.
© by Lecturio
How Common is Aortic Dissection? Epidemiology
• Uncommon: 5 30 cases/million
people/year
• 2000 cases annually in US
• Most common in patients aged 40 70,
peak at 50 65
• 3:1 male predominance
• In US: African American > Caucasian > Asian
• Familial predisposition
Pathophysiology of Aortic Dissection Pathology
Aortic dissection Intramural hematoma Penetrating aortic ulcer
FL TL TL TL
Formation of
entrance tear
Ascending
aorta TL
FL
Blood flow
Intimal
flap
TL TL
© by Lecturio
Pathophysiology of Aortic Dissection Pathology
Additional mechanisms of aortic dissection:
• Pathologic changes inFL theTLmedia can result in TL TL
dissection without injury to the intima.
• These changes can include cystic medial necrosis, or
congenital abnormalities in the medial elastic fibers.
• Genetic abnormalities affecting the elastic fibers can
include changes in the collagen or elastin proteins.
TL
• These changes
FL can result in aortic dissection without a
Bloodflow
false lumen created by intimal injury.
TL TL
© by Lecturio
Pathophysiology: Complications
• Compression of the true lumen hypoperfusion
• Aneurysmal dilation of the false lumen
• Propagation of the dissection with:
• Aortic insufficiency
• Cardiac tamponade
• Myocardial ischemia
• Stroke
• Renal or mesenteric infarction
© by Lecturio
Risk Factors Conditions that Increase Aortic Wall Stress Etiology
Hypertension
Atherosclerosis
Cocaine use
Aortic valve anomalies
Pregnancy
Risk Factors Conditions that Weaken or Injure the Intima Etiology
Connective tissue disorders
Syphilitic aortitis
Deceleration injuries
History Examination
• Pain of severe intensity (sensitivity 90%)
• Sudden onset pain (sensitivity 84%)
• Location of pain is variable:
• 57% in anterior chest
• 32% in posterior chest or back
• 23% in abdomen
• only present
in 39%, but quite specific.
© by Lecturio
Physical Exam Diagnosis
:
Pulse deficit: 31%
(though quite specific when detected)
Neurologic deficit: 17%
(also quite specific)
Diastolic murmur: 28%
Syncope: 13%
Hypertension: 50%
Chest X-Ray Examination
• Classic
• Widened mediastinum
• Obliteration of aortic knob
• Double aortic contour
• Inward displacement of
calcification
• Only 70 80% sensitive
case report of aortic trauma Mitsos AP, Chantler J, Konstantinou E, et al., https://openi.nlm.nih.gov/detailedresult.php?img
=PMC2740038_1757-1626-0002-0000006795-001&query=aortic+dissection&it=x,xg&lic=by&req=4&npos=6, CC BY 3.0, Resized
Chest X-Ray Examination
CXR should not be used to rule out aortic dissection!
Other Radiographic Studies Examination
Modality Sensitivity Specificity Pros Cons
Rapid
Computed tomography
85 100% 85 100% Readily available Requires contrast
angiography (CTA)
Noninvasive
Trans-esophageal No contrast required Limited availability
86 100% 90 100%
echocardiography No radiation Invasive
Magnetic resonance No iodinated contrast Limited availability
95 100% 94 98%
angiography (MRA) No radiation Time-consuming
CTA Examination
Ron Walls Robert Hockberger Marianne Gausche-Hill, Rosen's Emergency Medicine: Concepts and Clinical Practice, 9th Edition, 2017,
p. 1024, Fig. 75.2, Elsevier
Classification of Aortic Dissection Diagnosis
Stanford
A Ascending Stanford I II III
De Bakey A A B
B Descending
De Bakey
Ascending/
I descending
II Ascending only
III Descending only
IIIa Thoracic only
Extension to
IIIb abdomen
Peter Cameron & George Jelinek & Anne-Maree Kelly & Anthony F. T. Brown & Mark Little,Textbook of Adult Emergency Medicine, 4th
Edition, 2014, [278], Churchill Livingstone (Elsevier)
Aortic Dissection Guidelines
• Identify patients at risk for acute dissection.
• Assess those at risk based on risk factors (pain pattern, exam findings, imaging)
• Low risk: Continue with diagnostic evaluation as necessary
• Intermediate risk: Evaluate first for STEMI, then for acute dissection
• High risk: CT surgery consultation and CTA are immediately necessary
• If the patient is clinically unstable, order a TEE, not a CTA.
How is this Condition Treated? Management
• Definitive treatment is based on
classification:
• Type A requires emergent surgical
intervention.
• Type B is usually managed medically.
• Initial ED management is identical for both
dissection types.
• Aortic dissection is always an emergency!
ED Management The Basics Management
Oxygen to maintain adequate
saturation
Cardiac monitor and frequent vital
sign checks
Adequate vascular access
Type and crossmatch for blood
IV fluids/blood if needed for
hypotension
Monitor urine output
Arterial line placement for continuous
BP monitoring
Surgical Consultation Management
For Type B, surgery may be
Type A
indicated for selected patients:
• Call immediately! • Rupture or impending rupture
• Propagation of dissection
• Enlarging intramural hematoma
• Development of aneurysm
• Compromise of major aortic
branches
Surgical Consultation Management
For type B, ruptures or bleeding should be treated with
surgery!
ED Medical Management Management
Goal prevent rupture or propagation Agent of choice
of dissection beta-blockers
• Decrease hydrostatic pressure in • Lowers blood pressure
aorta (goal = SBP of 100 120)
• Decrease shear force from cardiac • Lowers heart rate
contraction
• Decreases myocardial contractility
Pro Tip! Prognosis
Use an agent that is given as a continuous infusion
so you can adjust blood pressure as needed. High-yield
Esmolol or labetalol are good choices.
ED Medical Management Management
If BP remains All agents should be For hypotension:
uncontrolled despite given as continuous IV
beta-blockers, consider: infusions. • Ensure adequate
intravascular volume with
• ACE-inhibitor fluid/blood first.
• Calcium channel blocker • Consider vasopressors
only once patient is
• Nitroprusside euvolemic.
Surgical Alternatives Management
• Open surgical repair with
aortic graft placement
• Thoracic endovascular aortic
repair (TEVAR)
• Goal is to occlude the
intimal tear, blocking flow
into false lumen.
• Improves flow through
true lumen and prevents
propagation.
Endovascular repair of aortic dissection Sueyoshi E, Onitsuka H, Nagayama H, et al., https://openi.nlm.nih.gov/detailedresult.php?img
=PMC4252497_40064_2014_1380_Fig3_HTML&query=&req=4&npos=-1, CC BY 4.0, Cropped and resized
Outcomes of Aortic Dissection Prognosis
Type Treatment Median 30-day mortality
Open repair 14%
Stanford Type A
TEVAR 7%
Open repair 16%
Stanford Type B TEVAR 6%
Medical management 7%
What Happens if the Condition is Left Untreated? Prognosis
If no treatment is implemented there is a 1 2% mortality
per hour for first 48 hours!
Suspected Aortic Dissection Care Pathway Management
Basic Stabilization (oxygen, monitor,
IV access, fluid/blood if hypotensive)
CTA
Type A Type B No dissection
Consult CT surgery Complicated Uncomplicated Search for
alternative cause of
Optimize medical management: symptoms
Place arterial line, beta-blocker infusion,
consider other agents as needed to reach
BP/pulse goals, blood/fluids/vasopressors for
hypotension
Take-Home Points
absent.
-risk
patients.
dissection.
CTA is the test of choice; MRA or TEE are
alternatives.
Take-Home Points
Consult surgery for Type A and complicated Type B
Optimize medical management for all:
Goal SBP = 100 120; pulse = 60 80
Beta-blockers are first line agents.
Learning Outcomes
✓ You can recognize possible aortic dissection based
on clinical signs and symptoms.
✓ You are able to perform appropriate diagnostic
workup for suspected aortic dissection.
✓ You can differentiate between dissection types.
✓ You can identify patients with dissection in need of
urgent surgical intervention.
✓ You know how to medically manage all patients with
dissection pending definitive treatment.
