1. AORTIC ANEURYSM &
COMPLICATIONS
Dr. P SANDEEP

2. Aortic root
1.

valve, annulus, and sinuses
Ascending aorta
2.

Root to the origin of the right
brachiocephalic A
Aortic arch
3.



Right brachiocephalic A to the
attachment of the ligamentum
arteriosum
Proximal (right brachiocephalic
artery to lt subclavian A)
Distal/Isthmus (lt subclavian A to
attachment of the ligamentum
arteriosum)
Descending thoracic aorta
4.


ligamentum arteriosum to the aortic
hiatus in the diaphragm
Aortic spindle:most proximal portion of
the descending thoracic aorta appears
slightly dilated

3. Aneurysm
True
aneurysm
Contain intima,
media, and
adventitia
Fusiform Dilatation
atherosclerosis
False
aneurysm
pseudoaneurysm
contained by
the adventitia
or
periadventitial
tissues.
Saccular
Penetrating
trauma
atherosclerotic
ulcers or
infection

4. Aortic Aneurysm
Thoracic
AA greater than 4 cm
DA greater than 3 cm
1.
2.
DA should never be larger than the AA at a
given scan level
The ratio of the coronal diameter of the AA to
that of the DA should be about 1.5:l.
Abdominal
Focal dilatation of the abdominal aorta
that is 50% greater than the proximal
normal segment or that is greater than
3cm in maximum diameter.
Less common
More common
Atherosclerosis (M.C)
Atherosclerosis (M.C)
Often identified incidentally on imaging
of the chest.
Presentation: Pain(m.c)
Mostly asymptomatic unless they leak or
rupture.
Ruptured aneurysms present with
severe abdominal or back pain and
hypotension / shock.
Ascending(Anterior) arch (neck pain) descending
(mid-scapular)
Due to compression or rupture
Descending aorta (at the level of the
ligamentum arteriosum, just distal to the
origin of the subclavian artery.)
Below the level of origin of renal arteries

5. Crawford classification of Thoracoabdominal aortic aneurysms

Type1:


Type II:


left subclavian A to aortic
bifurcation
Type III:


left subclavian A to renal A
mid-descending aorta to
aortic bifurcation
Type IV:

upper abdominal aorta and
all or none of the infrarenal

6. CAUSES




Atherosclerosis (most common)
Chronic aortic dissection
Vasculitis e.g. Takayasu arteritis
Connective tissue disorders :






Marfan syndrome
Ehlers-Danlos syndrome
Mycotic aneurysm
Traumatic pseudoaneurysm
Anastomotic pseudoaneurysm
Inflammatory abdominal aortic aneurysm
Associations of AAA:
 Common iliac artery (CIA) aneurysm
 Popliteal artery aneurysm

7. Role of imaging
1.
2.
3.
4.
Detection
Monitoring of rate of growth
Pre-operative planning
Post-operative follow-up

8. Radiography:
TAA:
Initial identification of thoracic aortic aneurysms can
be suspected from chest radiograph.
 Most commonly, a mediastinal mass or enlarged
segment of the aorta
 Curvilinear mural calcification
 Non-specific
Displacement and compression of the esophagus or
trachea and bronchi, may be visible.
 Erosion of the thoracic vertebrae and posterior ribs.
 Left pleural effusion suggests rupture


9. Radiography:
AAA:
 may be visible as an area of curvilinear
calcification in the para-vertebral region on
either abdominal or lumbar spine films

13. ULTRASONOGRAPHY
TAA:
 No role of transthoracic ultrasound of no
use.
 Transoesophageal echocardiography can
visualise much of the descending
aorta, but due to its invasive nature is not
routinely used.

14. ULTRASONOGRAPHY
AAA:
 Simple, safe and inexpensive.
 Sensitivity ~ 95% and specificity ~ 100%.
 Preferred choice for monitoring of small
aneurysms
 US may help determine the size of the
aneurysm and help identify hemoperitoneum.
 However, the utility of US for identifying an
impending rupture or a contained rupture of an
aneurysm is limited.

16. COMPUTED TOMOGRAPHY

Unenhanced CT:
 may
help detect an aneurysm rupture by
depicting an AAA with surrounding retroperitoneal
hemorrhage.
 Calcification

Contrast-enhanced CT:
 Size
of the aneurysmal lumen
 Presence of active extravasation
 Calcification
 Intraluminal thrombi
 Displacement or erosion of adjacent structures

17. TAA:
1. Relationship of the aneurysm to the arch
vessels
2.
Descending aorta:

3.
The esophagus is displaced to the right, and the
trachea and bronchi are displaced anteriorly.
Aortic arch and ascending aorta:

Produce compression rather than displacement
of adjacent mediastinal structures

18. 
AAA
 Relationship
of the aneurysm to the celiac a,
SMA, renal a, and IMA.

Mural thrombus calcification may be confused
for displaced intima in aortic dissection

19. CT angiography


Gold standard.
CT angiography has become routine for
imaging of a suspected rupture. (R/O
appendicitis, pancreatitis, or bowel obstruction )

Accurately delineates
 Size
and shape of the AAA
 Its relationship to branch arteries and aortic
bifurcation.
 In detecting and sizing common iliac artery
aneurysms.

35. MRI and MR angiography:
 Same as for CTA but can be more costly and
less widely available.

36. Aortic aneurysm, Marfan syndrome. Parasagittal spin-echo magnetic
resonance image demonstrates marked dilatation of the aortic root (A). A
smaller aneurysm (arrows) of the proximal descending aorta also is seen.

37. AORTOGRAPHY

Conventional aortography now has a limited
role in the preoperative evaluation of AAAs.
Drawbacks:
 underestimate the size of the aneurysm.
 invasive nature,
 cost
 risk of exposure to large amounts of iodinated
contrast.

39. Complications
TAA
1. Rupture
2. Distal embolisation
3. Fistula formation
1. aorto-oesophageal fistula
2. aorto-bronchial fistula
AAA
1. Rupture
2. Pseudoaneurysm from
chronic contained leak /
rupture
3. Distal thromboembolism &
Thrombotic occlusion of
branch vessel
4. Aorto-enteric fistula
5. Infection
6. Compression of adjacent
structures if large (rare)
7. Vertebral erosion

40. Signs of Impending rupture
Increase in size
Thrombus and calcifications:
1.
2.


3.
4.
5.
Decreased thrombus-to-lumen ratio
A focal discontinuity in circumferential wall
calcifications
High-attenuation crescent sign - sign of
impending rupture
Draped aorta sign - sign of contained rupture
Retroperitoneal hematoma

41. High attenuating crescent
sign



Specific sign of impending AAA rupture /
contained rupture.
Represents an acute hematoma or bleed
within either the mural thrombus or the
aneurysmal wall, especially when detected on
unenhanced CT-scans.
The crescent need to be well defined and of
higher attenuation than the psoas muscle on
enhanced scans or of higher attenuation than
that of the patent lumen on unenhanced
scans.

44. Draped aorta sign

Refers to indistinctness of the posterior wall of the
aorta from the adjacent structures .

The posterior aortic wall Is unidentifiable and follows
the vertebral contour (draped over vertebral body).

Associated with chronic contained rupture of an
abdominal aortic aneurysm with vertebral
erosion1.

Highly indicative of aortic wall deficiency and a

50. AORTIC RUPTURE
TAA:
 Aortic
aneurysms can rupture into the
mediastinum, pleural cavity, pericardium, or
adjacent luminal structures such as the airway or
esophagus
AAA:
 Rupture
most commonly involves the
posterolateral aorta with hemorrhage into the
retroperitoneum
 Accumulates in perinephric space, other
retroperitoneal compartments, duodenum, psoas
muscle and peritoneal cavity

51. AORTIC RUPTURE
In stable patient CT is first choice of imaging
1.
2.
3.
Characterize AAA (site, size, extent and relations)
Identify rupture
Contrast: differtiates perianeurysmal fibrosis
(Detectable enhancement) from hematoma (no
enhancement)
4.
In AAA to r/o
obstruction
appendicitis, pancreatitis, or bowel

54. False positives:
1.
Periaortic fibrosis
2.
Asymmetric thrombus
3.
Volume averaging of periaortic tissues with
lumen at the neck of aneurysm
4.
Unopacified 3rd and 4th part of duodenum
5.
Retroperitoneal lymphadenopathy

55. Aortobronchial fistula
 Manifests
clinically as hemoptysis
 CT as consolidation in the adjacent lung due to
hemorrhage
 Most aortobronchial fistulas (90%) occur between
the descending aorta and the left lung.


Communication with the
esophagus (aortoesophageal fistula) is less
com

56. Aortoesophageal fistula:
 Hematemesis and dysphagia.
 CT:
 Mediastinal
hematoma
 Intimate relationship of the aneurysm to the
esophagus,
 Rarely, contrast material extravasation into the
esophagus

58. Aortoenteric Fistulas:





Primary: atherosclerotic aortic aneurysms
Secondary: aortic reconstructive surgery.
M.C : duodenum (third and fourth portions).
Symptoms: abdominal pain, hematemesis, and
melena.
CT imaging features:



Abdominal aortic aneurysm, often with signs of
rupture
Intraluminal and periaortic extraluminal gas.
CECT: Contrast material extravasation from the aorta
into the involved portion of the bowel, if a patent

61. MANAGEMENT
1.
2.
open repair
endovascular repair
TAA
AAA
ascending aneurysm > 5.5
Aneurysm > 3cm
cm
descending aneurysm > 6.5
cm
Growth rate > 1 cm/year
Growth rate > 1 cm/year
Symptomatic patients
repaired regardless of size
Symptomatic patients
repaired regardless of size

62. CT in Post-op period for
complications
open repair:
1.



Endovascular repair:
2.






Graft dehiscence
Pseudoaneurysm formation
Infection
Endoleaks
Migration
Collapse
Pseudoaneurysm or Dissection
The native aorta may be left in situ and appears as
an irregular curvilinear area of dense calcification or
a rind of soft tissue, often with fluid between it and
the graft.
It should not be mistaken for dissection flap.