Blunt Traumatic Aortic Injury

1
Blunt Traumatic Aortic Injury

• A Review of Initial Diagnostic Modalities and a
  Proposed Diagnostic Algorithm
• Eur J Trauma
  20032912938
• Joseph Yuk Sang Ting
• Departments of Emergency Medicine, Mater Adult
  and Childrens Hospitals, Brisbane, Queensland,
  Australia.

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Introduction

• High immediate mortality from aortic injury due
  to exsanguination remains a major problem in
  trauma management
• Traumatic Aortic Injury (TAI) was 2nd most
  frequent cause of mortality from blunt injuries

3
Introduction

• TAI caused from shearing forces from rapid
  deceleration
• Blunt TAI transverse lesion close proximity of
  ligametum arteriosum
• A-aorta 5, D-aorta 1-3

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Introduction

• Diagnostic base high suspicion index
• Mechanism of injury History of rapid
  deceleration, high risk injury pattern
• Initial screen tools chest firm
• Normal mediastinum of TAI 8.3

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Introduction

• Only ½ - 2/3 of TAI had external sign
• Clinical findings systemic hypotension, upper
  limbs hypertension, asymmetry of limbs pulses,
  flow murmurs

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Introduction

• Prompt recognition and treatment in survivors
  improves outcome
• The outlook for those treated nonsurgically is
  poor, with lt 2 surviving long-term owing to the
  formation of a chronic pseudoaneurysm

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Introduction

• Imaging tools
• 1. Chest firms
• 2. Chest helical computed tomography
  
• angiography (CT-A)
• 3. Transesophageal exhocardiography
• (TEE)
• 4. Aortography
• 5. MRA
• 6. Endovascular ultrasonography (USS)
• 7. Intraarterial digital subtraction
  angiography (IA-
• DSA)

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Introduction

• Evaluation of mediastinum for blunt TAI is not
  well defined
• Invastigation must confirm or exclude TAI with
  certainly due to potentially lethal of missed
  dianosis and risk of unnecessary surgical
  intervention.

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Material and Methods

• A Medline search was conducted using the terms
  traumatic aortic injury, aortic injury,
  aortic trauma, and thoracic trauma
• From 1966 until December 2002.
• Investigations used in the diagnostic evaluation
  of blunt TAI were reviewed and an initial
  investigative approach to this condition
  formulated.

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Material and Methods

• This review focuses on imaging modality are more
  established and have additional diagnostic
  utility for nonvascular injury

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Results

• Aortography
• Diagnostic standard
• Sensitivity 100, specificity gt98
• less false negative results

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Aortography

• Establishes the diagnosis
• Defines the anatomy of lesion
• Identifies additional sites of aortic injury such
  as supraaortic vessel injury
• Abdominal aortic injury

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Aortography

• Less false postive false negative rate
• False postive may result from atheromatous or
  ulcerated aortic wall and ductal diverticula
• False negatives result from inadequate contrast
  distribution, opacification of aortic arch,
  thrombosis within pseudoaneurysm and inadequate
  numbers of views

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Aortography

• Disadvantages
• Invasive, not widely available, time consuming,
  difficult to interpret
• Intra-arterial admistration of contrast medium
• Necessitates transfer of unstable patient out of
  resuscitation area
• Miss minor aortic injuries intramural hematoma
  , dynamic intimal flap
• Mortality rate 0.03

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Plain Chest Radiography

• Normal CxR is very sensitive for mediastinal
  hematoma, gt90 negative predictive value
• Unable to predict aortic injury
• Up to 8.4 of aortic injury proven after a normal
  chest firm
• Sensitivity gt80, but specificity lt50
• Low positive predictive value 5-20

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Plain Chest Radiography

• Quality of trauma chest firms vary widely
• Similar chest firm abnormality showed in
  nonaortic injuries
• Better at excluding rather than predicting TAI
• Abnormality warrant further investigation
• May have role in the serial evaluation while
  other investigations are not available

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Computed Tomography Angiography (CT-A)

• Well established for TAI in hemodynamically
  stable patient
• Preferred initial investigation for TAI
• High negative predictive value
• Positive CT-A will diagnoses TAI or at least
  suggest it
• Sensitivity close to 100

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CT-A vs. Aortography
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CT-A vs. Aortography
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CT-A vs. Aortography
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CT-A vs. Aortography

• CT-A found to be more sensitive (100 vs. 92)
  but less specific (83 vs. 99) than aortography
• Negative predictive value 100 but positive
  predictive value 50 only with CT-A
• A normal mediastinum in CT-A required no further
  evaluation
• An equivocal CT-A is clarified with aortography

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CT-A vs. Aortography

• Gavant formulated a CT-A grades for TAI
• Grade 0 Normal mediastinum aorta
• Grade 1 Abnormal media. normal A.
• Grade 2 Minimal Aortic injury with periaortic
  hematoma
• Grade 3 Confined aortic injury
• Grade 4 Aortic rupture

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CT-A vs. Aortography

• Grade 0,1 Clinical follow up
• Grade 2,3 Aortography
• Grade 4 immediate surgical treatment

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CT-A

• CT-A is recommended in hemodynamically stable
  blunt thoracic trauma patient with high risk
  injury mechanism despite a normal chest firm
• CT-A is able to demostrate nonaoric mediatinal,
  pulmonary and thoracic vertebral injuries not
  detected by TEE or aortography

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Transesophageal Echocardiography (TEE)

• Low diagnostic yield
• Better in unstable patient without impending
  resuscitation
• Used to monitor surgical repair or follow up of
  equivocal cases
• High operator-dependent

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TEE

• Smith et al. prosectively assessed 93 of 101
  patient with blunt thoracic injury with abnormal
  chest firm.
• Sensitivity 100, specificity 98
• Positive predictive value 99
• Others revealed similar results

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TEE - Benefit

• Less time-consuming
• Can be performed in the treatment area on
  unstable patient without interfering with
  resuscitative
• Enable assessment of injury to the heart and its
  valves
• Can identify mural thrombus and intimal injury
• Assess the descending aorta than the proximal
  arch and distal ascending aorta

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TEE - limitation

• Pneumomediastinal impairs visualization
• Aortic atheroma can be mistaken for intimal
  injury and flap
• Contraindicated with facial, cervical spine and
  esophageal injury

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Magnetic Resonance Angiography (MRA)

• Do not have a role in emergency evaluation
• Motion artifact mimic dissection
• Contraindication in pacemakers metalic foreign
  bodies
• MRA useful for monitoring posttraumatic contained
  aortic pseudoaneurysm for which repair may be
  delayed

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Endovascular ultrasound (USS)

• Clarified subtle aortography changes that may
  represent mural injury withour psudoaneurysm or
  initimal flap
• Expensive instrument
• High operator or interpreter dependent
• However, high specificity while combined use with
  aortography
• No Useful role at emergency request

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Intra-arterial Digital Subtraction angiography
(IA-DSA)

• 100 accuracy
• Compared to convetional aortography, IA-DSA in
  faster to performed , uses smaller arterial
  catheter and requires less contrast

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Conclusion
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Conclusion
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Thanks for your attention