Download Contents Under Pressure: Radiologic Findings of Abdominal Aortic Aneurysmal Rupture

Zev Wiener
Gillian Lieberman, MD
Contents Under Pressure:
Radiologic Findings of
Abdominal Aortic Aneurysmal
Rupture
Zev Wiener
Harvard Medical School Year III
Gillian Lieberman, MD
Zev Wiener
Gillian Lieberman, MD
Our Patient: Initial Presentation
• History of Present Illness:
63 year-old woman with a known history
of abdominal aortic aneurysm
(AAA)
presents with acute onset chest and
lower back pain s/p MVC
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Zev Wiener
Gillian Lieberman, MD
Our Patient: Initial Presentation
• Past Medical History:
Hypercholesterolemia, PUD, s/p gastric
bypass
• Family History: AAA in father and uncle
• Vitals: Hypotensive in the 80’s
• Labs: WNL
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Zev Wiener
Gillian Lieberman, MD
Differential Diagnosis
GI
• Appendicitis
• Small bowel obstruction
• Large bowel obstruction
• Gastritis / PUD
• Diverticular disease
• Pancreatitis
• Ischemic bowel
• Reflux
GU
• Pyelonephritis
• Nephrolithiasis
Cardiovascular
• AAA
• Aortic Dissection
• MI
Miscellaneous
• Musculoskeletal pain
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Zev Wiener
Gillian Lieberman, MD
Differential: Potential Pitfalls
In particular, ruptured AAA is often
misdiagnosed as:
-Renal colic
-Diverticulitis
-MI
-MSK back pain
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Zev Wiener
Gillian Lieberman, MD
Our Patient: Diagnosis
Given patient’s history, a complication of
AAA is very high on the differential
 What is an AAA?
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Zev Wiener
Gillian Lieberman, MD
Abdominal Aortic Aneurysm
(AAA)
Dilatation of the abdominal
aorta to > 1.5 times its
normal diameter
Normal diameter is approx.
2 cm
An AAA is therefore defined
as an aortic diameter
greater than 3 cm
http://www.health‐news‐blog.com/blogs/permalinks/4‐2008/will‐screening‐for‐aortic‐aneurysm‐be‐effective.html 7
Zev Wiener
Gillian Lieberman, MD
Anatomy of the Aorta
95% of AAA’s are
infrarenal
About 2/3 extend
into one or both
of the iliac
arteries as well
8
http://www.dartmouth.edu/~humananatomy/figures/chapter_30/30-1.HTM
Zev Wiener
Gillian Lieberman, MD
AAA: Risk Factors
•
•
•
•
•
•
•
Odds Ratio
Smoking
5.57
Male sex
4.56
Positive family history
1.95
White versus black race
2
Atherosclerosis
1.5
Hypertension
1.2
(Diabetes)
(0.54)
Aneurysm Detection and Management (ADAM) Veterans Affairs Cooperative Study Group, Ann Inter Med 3/97
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Zev Wiener
Gillian Lieberman, MD
AAA Rupture: Risk Factors
•
•
•
•
Aneurysm diameter
Rate of expansion
Female gender
Other less proven factors
-Smoking
-Decreased FEV1
-Amino terminal procollagen propeptide10
Zev Wiener
Gillian Lieberman, MD
Risk of Rupture:
Diameter
Diameter (cm)
< 4.0
4.0-4.9
5.0-5.9
6.0-6.9
7.0-7.9
>8.0
Annual Risk (%)
0
0.5-5
3-15
10-20
20-40
30-50
J Vasc Surg 2003 May;37(5):1106-17
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Zev Wiener
Gillian Lieberman, MD
Risk of Rupture:
Rate of Increase
• 0.19 cm
baseline
• 0.27 cm
baseline
• 0.35 cm
baseline
per year for aneurysms 2.8 to 3.9 cm in
diameter
per year for those 4.0 to 4.5 cm in
diameter
per year for those 4.6 to 8.5 cm in
diameter
• Rate of increase is more rapid in smokers
(Estimates of 20-25% increase in rate)
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Zev Wiener
Gillian Lieberman, MD
Risk of Rupture:
Gender
Risk of rupture in women is significantly
higher than in men
May reflect smaller initial lumenal diameter
13
Zev Wiener
Gillian Lieberman, MD
Risk of Rupture:
Other Factors
• Diameter is not the whole story…
-10 - 24% of ruptured AAAs were less than 5 cm in
diameter
(Nicholls, et al)
-Some have advocated looking at geometry of
aneurysm (contribution to wall stress) as
opposed to mere diameter
(Vorp, et al)
-Other factors include ongoing smoking, decreased
FEV1, diabetes mellitus, and serum marker
amino-terminal procollagen propeptide
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Zev Wiener
Gillian Lieberman, MD
AAA: Importance of Early Detection
• When repaired electively, mortality is 0.95%
• When repaired after rupture, mortality is
up to 75%
Alexander S, Bosch JL, Hendriks JM, Visser JJ, Van Sambeek MR. The 30‐day mortality of ruptured abdominal aortic aneurysms: influence of gender, age, diameter and comorbidities. J Cardiovasc Surg (Torino). Oct 2008;49(5):633‐7
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Zev Wiener
Gillian Lieberman, MD
Clinical Presentation of AAA
Pre-Rupture
Post-Rupture
-Usually asymptomatic
-Severe, constant pain in
abdomen or back.
-Vague epigastric
discomfort
-Tachycardia /
Hypotension
-Mild back/abdominal pain
-Pulsatile abdominal mass
-Nausea and vomiting
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Zev Wiener
Gillian Lieberman, MD
Menu of Tests
Pre-Rupture
• Plain film
• Ultrasound (US)
• Computed Tomography
(CT)
• Magnetic Resonance
Angiography (MRA)
• Digital Subtraction
Angiography (DSA)
Post-Rupture*
• CT
• US
*If not diagnosed clinically
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Zev Wiener
Gillian Lieberman, MD
Our Patient
The E.D. opted for C.T.
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Zev Wiener
Gillian Lieberman, MD
Diagnosis of Rupture: CT
PRO’S
-Detailed imaging of aneurysmal size, location,
and neighboring anatomy
-Delineates presence of thrombus
-Detect active extravasation
-Reveals systemic effects of rupture
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Zev Wiener
Gillian Lieberman, MD
CON’S
-TIME
Avg. time to diagnosis on CT = 83 minutes
(compared to 5.4 minutes of ultrasound)
(Plummer D, et al: Abstract at 1998 SAEM, Chicago, IL.)
-Contrast (allergy/ renal function)
-Expensive
20
Zev Wiener
Gillian Lieberman, MD
Our patient’s CT findings…
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Zev Wiener
Gillian Lieberman, MD
Out Patient: Aortic Arch
Jagged,
irregular
aortic arch
PACS, BIDMC
Axial (C+) CT
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Zev Wiener
Gillian Lieberman, MD
Our Patient: Aorta
Free fluid
Calcified
aorta
PACS, BIDMC
Axial (C+) CT
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Zev Wiener
Gillian Lieberman, MD
Our Patient:
High Attenuating Crescent Sign
Possible
intramural
hematoma
PACS BIDMC
Axial (C+) CT
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Zev Wiener
Gillian Lieberman, MD
Companion Patient:
High Attenuating Crescent Sign
*
*
http://www.radiologyassistant.nl/en/452fe3aa7ef9c
Represent an acute hematoma within either the mural
thrombus or the aneurysmal wall, strongly associated
with AAA rupture (75% PPV)
http://rsna2005.rsna.org/rsna2005/V2005/conference/event_display.cfm
?id=66601&em_id=4415819
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Zev Wiener
Gillian Lieberman, MD
Our Patient: Hematoma
Extravasated
contrast
Retroperitoneal
hematoma
PACS, BIDMC
Axial (C+) CT
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Zev Wiener
Gillian Lieberman, MD
Our Patient: Site of Rupture
Site of rupture
Widest
diameter
(post-rupture)
=
4.7 cm
PACS, BIDMC
Axial (C+) CT
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Zev Wiener
Gillian Lieberman, MD
Most Common Site of Rupture
•
•
•
•
•
•
Right lateral wall - 28%
Pelvic arteries - 22%
Posterior wall - 19%
Left lateral wall - 17%
Anterior wall - 10%
Suprarenal - 4%
Radiology. Jun 2007;243(3):641‐55.
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Zev Wiener
Gillian Lieberman, MD
Our Patient: Site of Aneurysm
Renal artery
PACS, BIDMC
Coronal (C+) CT
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Zev Wiener
Gillian Lieberman, MD
Infrarenal AAA’s
95% of AAA’s are infrarenal
About 2/3 extend into one or both of the iliac
arteries as well
30
Zev Wiener
Gillian Lieberman, MD
Our Patient: Aneurysm Shape
Possible fusiform
morphology (postrupture)
PACS, BIDMC
Coronal (C+) CT
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Zev Wiener
Gillian Lieberman, MD
Shape of Aneurysm
http://neuro.wehealny.org/endo/images/11_01.jpg
Saccular AAA’s are thought to be more
prone to rupture than fusiform AAA’s.
-CT “tortuosity index” may provide a
more accurate prediction of rupture
Annals of Vasc. Surgery, 22:1 88-97
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Zev Wiener
Gillian Lieberman, MD
Systemic Effects of Aneurysmal
Rupture in our Patient
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Zev Wiener
Gillian Lieberman, MD
Our Patient: Flattening of IVC
“Slit-like” IVC
PACS, BIDMC
Axial (C+) CT
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Zev Wiener
Gillian Lieberman, MD
Our Patient: Renal Displacement
Anteriorly displaced
R kidney
PACS, BIDMC
Axial (C+) CT
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Zev Wiener
Gillian Lieberman, MD
Site of Hemorrhage
• Retroperitoneal - 85.3%
• Peritoneal - 7.1%
• Inferior vena cava (IVC) or iliac vein 5.8%
• Enteric - 1.8%
J Vasc Surg. Jan 8 2009
36
Zev Wiener
Gillian Lieberman, MD
Retroperitoneum: Anatomy
37
http://radiographics.rsna.org/content/28/6/1571/F2.large.jpg
Zev Wiener
Gillian Lieberman, MD
Our Patient: Kidneys
Wedge shaped
segment of
hypoenhancement
PACS, BIDMC
Axial (C+) CT
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Zev Wiener
Gillian Lieberman, MD
AAA: Renal Involvement
As many as 30% of patients with AAA
have concomitant renal artery stenosis
Iezzi R, Cotroneo AR, Filippone A, Di Fabio F, Santoro M, Storto ML. MDCT angiography in abdominal aortic aneurysm treated with
endovascular repair: diagnostic impact of slice thickness on detection of endoleaks. AJR Am J Roentgenol. Dec 2007;189(6):1414-20.
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Zev Wiener
Gillian Lieberman, MD
Our Patient: Liver
Wedge shaped
area of
hypoperfusion
PACS, BIDMC
Axial (C+) CT
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Zev Wiener
Gillian Lieberman, MD
Other Possible CT Findings
That Were Not Evident in Our
Patient
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Zev Wiener
Gillian Lieberman, MD
AAA Rupture: Periaortic Stranding
http://www.ajronline.org/content/vol188/issue1/images/large/01_05_1554_03C.jpeg
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Zev Wiener
Gillian Lieberman, MD
Focal Calcium Discontinuity
http://www.radiologyassistant.nl/en/452fe3aa7ef9c
47% PPV
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Zev Wiener
Gillian Lieberman, MD
Tangential Calcium
http://www.radiologyassistant.nl/en/452fe3aa7ef9c
74% PPV
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Zev Wiener
Gillian Lieberman, MD
Draped Aorta
http://www.radiologyassistant.nl/en/452fe3aa7ef9c
61% PPV
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Zev Wiener
Gillian Lieberman, MD
Are there any other options for
evaluation of a ruptured AAA?
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Zev Wiener
Gillian Lieberman, MD
Screening: Ultrasound
• Excellent screening tool prior to rupture
– Simple and safe
– Cost-effective
– No exposure to ionizing radiation
– Sensitivity and specificity nearly 100%
– However, highly operator dependent
http://www.meded.virginia.edu/courses/
rad/edus/index8.html
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Zev Wiener
Gillian Lieberman, MD
Diagnosis of Rupture: Ultrasound
- Not as reliable as CT, but may be the only
viable diagnostic option for the
hemodynamically unstable patient
- Use of contrast enhanced US aids detection
- One report cited a 4% sensitivity in US
detection of rupture
- When combined with other clinical
factors, however, sensitivity was 95%
AJR 2005; 184:423-427
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Zev Wiener
Gillian Lieberman, MD
Diagnosis of Rupture:
Baseline Ultrasound
http://www.ajronline.org/content/vol184/issue2/images/large/00_03_0181_01a.jpeg
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Zev Wiener
Gillian Lieberman, MD
Diagnosis of Rupture:
Contrast Enhanced Ultrasound
http://www.ajronline.org/content/vol184/issue2/images/large/00_03_0181_01b.jpeg
50
Zev Wiener
Gillian Lieberman, MD
Diagnosis of Rupture:
Contrast Enhanced Ultrasound
http://www.ajronline.org/content/vol184/issue2/images/large/00_03_0181_02anew.jpeg
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Zev Wiener
Gillian Lieberman, MD
Diagnosis of Rupture:
Color-Flow Doppler Ultrasound
http://www.vmth.ucdavis.edu/cardio/cases/case38/color_flow.htm
- Color-flow Doppler can aid in detecting the site of
extravasation
- Adjustment to low velocity scales may be necessary
to register leaks with low flow rates
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Zev Wiener
Gillian Lieberman, MD
CT vs US
Average time to diagnosis by bedside US =
5.4 minutes
Average time to diagnosis by CT =
83 minutes
Plummer D, et al: Abstract at 1998 SAEM, Chicago, IL.
53
Zev Wiener
Gillian Lieberman, MD
Our Patient: Treatment
Patient underwent emergent open repair of
AAA with placement of a 12 mm Dacron
graft
54
https://clevelandclinic.org/heartcenter/pub/guide/disease/aorta_marfan/marfansurgery_act
ual.htm
Zev Wiener
Gillian Lieberman, MD
Treatment of Ruptured AAA
May be repaired open or endovascularly
British Journal of Radiology (2005) 78, 62-64
http://www.gvg.org.uk/aaagraft.jpg
55
Zev Wiener
Gillian Lieberman, MD
Our Patient: 4 Month Follow Up
Normal sized
Lumen
Kidney
PACS, BIDMC
Axial (C+) CT
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Zev Wiener
Gillian Lieberman, MD
Our Patient: 4 Month Follow Up
Thickened bowel
wall
PACS, BIDMC
Axial (C+) CT
57
Zev Wiener
Gillian Lieberman, MD
Potential Postoperative
Complications
•
•
•
•
•
•
•
•
Colonic ischemia (1st week)
Aortoenteric fistula
Atheroembolism
Declamping hypotension
Acute renal failure
Impotence (sympathetic plexus injury)
Anterior spinal syndrome
Graft infection
58
Zev Wiener
Gillian Lieberman, MD
Summary
- Ruptured AAA can be diagnosed clinically, with
CT, or with US
- While CT can provide exquisite detail regarding
the rupture and systemic effects, the necessary
time sacrifice is a considerable drawback
- Ultrasound is a rapid diagnostic modality, but is
highly operator dependent and not as
informative
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Zev Wiener
Gillian Lieberman, MD
Acknowledgements
Rich Rana, MD
Gillian Lieberman, MD
Prachi Dubey, MD
Graham Frankel
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Zev Wiener
Gillian Lieberman, MD
References
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•
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•
Alexander, S. "The 30-day Mortality of Ruptured Abdominal Aortic Aneurysms: Influence of Gender, Age, Diameter and
Comorbidities." Journal of Cardiovascular Surgery (Torino) 49.5 (2008): 633-7.
Brewster, D. C. "Guidelines for the Treatment of Abdominal Aortic Aneurysms. Report of a Subcommittee of the Joint
Council of the American Association for Vascular Surgery and Society for Vascular Surgery." J Vasc Surg 37.5 (2003): 110617.
Catalano, O. "Contrast-Enhanced Sonography for Diagnosis of Ruptured Abdominal Aortic Aneurysm." AJR Am J
Roentgenol 184 (2005): 423-7.
Iezzi, R. "Contrast-enhanced Ultrasound versus Color Duplex Ultrasound Imaging in the Follow-up of Patients after
Endovascular Abdominal Aortic Aneurysm Repair." Journal of Vascular Surgery (2009).
Iezzi, R. "MDCT Angiography in Abdominal Aortic Aneurysm Treated with Endovascular Repair: Diagnostic Impact of Slice
Thickness on Detection of Endoleaks." AJR Am J Roentgenol 189.6 (2007): 1414-20.
Morales, J. P. "Endovascular Repair of a Ruptured Abdominal Aortic Aneurysm under Local Anaesthesia." British Journal of
Radiology 78 (2005): 62-4.
Nicholls, S. C. "Rupture in Small Abdominal Aortic Aneurysms." Journal of Vascular Surgery 28.5 (1998): 884-8.
Norman, P. E. "Abdominal Aortic Aneurysm: the Prognosis in Women Is Worse than in Men." Circulation 115 (2007): 2865.
Pappu, S. "Beyond Fusiform and Saccular: A Novel Quantitative Tortuosity Index May Help Classify Aneurysm Shape and
Predict Aneurysm Rupture Potential." Annals of Vascular Surgery 22.1 (2008): 88-97.
Stavropoulos, S. W. "Imaging Techniques for Detection and Management of Endoleaks after Endovascular Aortic Aneurysm
Repair." Radiology 243.3 (2007): 641-55.
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