Jean Kang, HMS III Gillian Lieberman, MD
April 2002
Endovascular Repair of Abdominal Aortic Aneurysms: Preoperative Evaluation Jean Kang, Harvard Medical School Year III Gillian Lieberman, MD
Jean Kang, Kang HMS III Gillian Lieberman, MD
Our Patient z z z
z
74 yr old female with known AAA since 1992. Most recent US showed AAA with diameter of 4.8 cm. Referred from OSH to evaluate for possible endovascular repair of AAA. Pertinent history include: – Type II DM – HTN – S/P LCEA
– FHx of MI – Smoker 2
Jean Kang, HMS III Gillian Lieberman, MD
Definition z
z
Diameter exceeding the expected normal caliber by at least 50%. Normal diameter of abdominal aorta = 2.0 cm (1.4-3.0 cm).
celiac artery SMA
IMA z
z
Abdominal aorta is the most common site of arterial aneurysm. 95% of AAA are infrarenal.
www.yoursurgery.com
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Jean Kang, HMS III Gillian Lieberman, MD
Epidemiology z Incidence
of ~36 per 100,000. z Up to 9% of persons > 65 yo. z Natural
history of AAA is progressive expansion and eventual rupture. z Overall mortality rate after rupture 78-94%. z Ruptured AAA results in 15,000 deaths per year in the US. 4
Jean Kang, HMS III Gillian Lieberman, MD
Risk of Rupture z z
z
Size of the aneurysm Increased in women, patients with HTN and COPD. When to offer AAA repair based on 1) Rupture risk z z
z
< 4 cm – follow w/ US q 6 mo 4-5.5 cm – additional info needed > 5.5 cm or expands > 0.5 cm in 6 mo – repair indicated
2) Life expectancy 3) Operative Risk
Hallett J 2000
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Jean Kang, HMS III Gillian Lieberman, MD
Endovascular Surgery z z
First introduced by Parodi and associates in 1991. Less invasive than open surgery. – – – –
z z
Shorter hospital stay Shorter ICU stay Less blood loss Earlier return to function
Technical success of 98-99%. 30-day mortality rate (~3%) comparable to open surgery. 6
Jean Kang, HMS III Gillian Lieberman, MD
Endovascular Surgery (con’t) z
AneuRx stent-graft
Yusuf 2000
Ancure endograft hooks of the proximal attachment system
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Jean Kang, HMS III Gillian Lieberman, MD
Endovascular Surgery (con’t)
Yusuf 2000
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Jean Kang, HMS III Gillian Lieberman, MD
Role of Radiologic Imaging in Endovascular Surgery z z
Preoperative evaluation Intraoperative imaging – Proper endograft placement – A road map for orientation during procedure
z
Postoperative follow up – Immediate post op check – At 1, 6, and 12 mo post op, then q 1 yr thereafter – Endoleak, graft migration, stenosis, and kinking 9
Jean Kang, HMS III Gillian Lieberman, MD
Preoperative Evaluation z Determine
the feasibility of an endograft.
– Anatomy – Quality of the vessel wall
z Determine
the dimensions of endograft
– Accurate measurements important to avoid
complications (eg endoleak, graft migration, graft kinking)
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Jean Kang, HMS III Gillian Lieberman, MD
Preoperative Evaluation (con’t) Proximal neck may be too short. proximal neck aortic aneurysm distal attachment sites
Yusuf 2000
Distal attachment site may not be suitable.
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Jean Kang, HMS III Gillian Lieberman, MD
Preoperative Imaging z CT
with 3-D Reconstruction z Angiography z MRA z IVUS
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Jean Kang, HMS III Gillian Lieberman, MD
Spiral CT with 3-D Reconstruction z
Primary imaging modality today to – – – –
Measure Assess extent and complexity of the aneurysm Assess quality of aorta proximal and distal attachment sites Evaluate occlusive disease
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Jean Kang, HMS III Gillian Lieberman, MD
Spiral CT with 3-D Reconstruction (con’t) z
3D reconstruction allows accurate length and diameter measurements.
Fillinger 1999
slice reformatted perpendicular to the vessel
a conventional axial CT slice 14
Jean Kang, HMS III Gillian Lieberman, MD
Spiral CT with 3-D Reconstruction (con’t) z
Specialized measurement software allows additional features.
centerline measurement visualize endograft
Fillinger 1999
Yusuf 2000
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Jean Kang, HMS III Gillian Lieberman, MD
Our Patient: CT calcification
CT without contrast BIDMC PACS
CT with contrast 16
Jean Kang, HMS III Gillian Lieberman, MD
Our Patient: CT (con’t) s/p cholecystectomy right renal artery
SMA left renal artery
at the level of the right renal artery BIDMC PACS
15mm below the right renal artery 17
Jean Kang, HMS III Gillian Lieberman, MD
Our Patient: CT (con’t)
Maximum diameter = 52 x 54.2 mm BIDMC PACS
Bifurcation of the aorta 18
Jean Kang, HMS III Gillian Lieberman, MD
Our Patient: CT 3-D Reconstruction (MIP) z
Maximum intensity projection
z
3-D imaging technique that permits separation of the enhanced lumen from high attenuation structures within the vessel wall
z
Can readily detect calcification in the vessel wall
z
Poor depiction of vessels that overlap each other – Circumvent this problem by generating multiple MIPs
that rotate about an imaginary axis 19
Jean Kang, HMS III Gillian Lieberman, MD
Our Patient: CT 3-D Reconstruction (MIP) poor depiction of vessels that overlap
calcifications
BIDMC PACS
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Jean Kang, HMS III Gillian Lieberman, MD
Our Patient: CT 3-D Reconstruction (MIP)
BIDMC PACS
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Jean Kang, HMS III Gillian Lieberman, MD
Angiography z Used
as part of preoperative evaluation z Sensitive for evaluating occlusive disease z Only the inner lumen is imaged – Cannot evaluate the true lumen diameter,
extent of thrombus, plaque and calcification z 2-D
projection of a 3-D structure z Invasive 22
Jean Kang, HMS III Gillian Lieberman, MD
Angiography (con’t) •Angiography may underestimate the true diameter of the aneurysm.
noncalcified plaque and a thrombus
Angiogram Fillinger 1999
calcified plaque
3-D reconstruction from CT data
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Jean Kang, HMS III Gillian Lieberman, MD
Angiography (con’t)
Calibrated catheter may underestimate the length of the aneurysm.
Fillinger 1999
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Jean Kang, HMS III Gillian Lieberman, MD
Our Patient: Angiogram
frontal view BIDMC PACS
calibrated catheter
lateral view 25
Jean Kang, HMS III Gillian Lieberman, MD
MRA z z z z
z z z
Poorer resolution compared to CT Patient discomfort, contraindications Cost Reserved for patients with severe renal insufficiency
IVUS
Operator dependent Invasive Excellent for post op completion studies to evaluate z
graft approximation z graft stenosis 26
Jean Kang, HMS III Gillian Lieberman, MD
Our Patient: Preoperative Evaluation Summary z
“Fusiform infrarenal abdominal aortic aneurysm with diameter of 52 x 52mm and length of 12.5cm” z “Moderate calcification of the aorta” z “Good length of infrarenal abdmonial aortic neck” z “Without evidence of iliac or aortic stenotic disease” z
Our patient underwent endovascular repair of AAA…
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Jean Kang, HMS III Gillian Lieberman, MD
Our Patient: Endovascular Repair
proximal graft attachment site
preoperative angiogram BIDMC PACS
distal graft attachment sites
postoperative angiogram 28
Jean Kang, HMS III Gillian Lieberman, MD
Our Patient: Postoperative CT thrombus within the aneurysm sac
iv contrast within the endograft
axial view BIDMC PACS
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Jean Kang, HMS III Gillian Lieberman, MD
Our Patient: Postoperative CT
proximal attachment site
thrombus within the aneurysm sac
3D reconstruction BIDMC PACS
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Jean Kang, HMS III Gillian Lieberman, MD
In Summary z
Radiologic imaging plays an important role in preoperative, intraoperative, and postoperative evaluation for endovascular repair.
z
Preoperatively, CT with 3-D reconstruction and angiography are used to – assess suitability for endovascular repair and – measure endograft dimensions
z
Accurate assessment is essential in order to avoid any complications. 31
Jean Kang, HMS III Gillian Lieberman, MD
References z z z z z z z
z z
Brink, J. Technical Aspects of Helical (Spiral) CT. Radiologic Clinics of North America 1995; 33(5): 825-841. Fillinger M. New Imaging Techniques in Endovascular Surgery. Surgical Clinics of North America 1999; 79(3): 451-475. Hallet J. Management of Abdominal Aortic Aneurysms. Mayo Clinic Proceedings 2000; 75(4): 395-399. Rubin G, Silverman S. Helical (Spiral) CT of the Retroperitoneum. Radiologic Clinics of North America 1995; 33(5): 913-932. Thompson R. Detection and Management of Small Aortic Aneurysms. NEJM 2002; 346(19): 1484-1486. Yusuf S, Marin M, Ivancev K, Hopkinson B, eds. Operative Atlas of Endoluminal Aneurysm Surgery. Oxford, UK: Isis Medical Media Ltd, 2000. Zarins C, Wolf Y, Lee A, Hill B, Olcott C, Harris E, Dalman R, Fogarty T. Will Endovascular Repair Replace Open Surgery for Abdominal Aortic Aneurysm Repair? Annals of Surgery 2000; 232(4): 501-507. www.uptodate.com www.yoursurgery.com 32
Jean Kang, HMS III Gillian Lieberman, MD
Acknowledgements z Matthew
Spencer, MD z Daniel Saurborn, MD z Gillian Lieberman, MD z Pamela Lepkowski z Larry Barbaras and Cara Lyn D’amour
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