Endovascular Repair of Endovascular Repair of Abdominal Aortic Aneurysms: Abdominal Aortic Aneurysms:

Preoperative EvaluationPreoperative Evaluation

Jean Kang, Harvard Medical School Year IIIGillian Lieberman, MD

Jean Kang, HMS IIIGillian Lieberman, MD

April 2002

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Jean Kang, HMS III

Gillian Lieberman, MD

Our PatientOur Patient74 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

Jean Kang

Gillian Lieberman, MD

– FHx of MI– Smoker

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Jean Kang, HMS III

Gillian Lieberman, MD

DefinitionDefinitionDiameter exceeding the expected normal caliber by at least 50%.Normal diameter of abdominal aorta = 2.0 cm (1.4-3.0 cm).

Abdominal aorta is the most common site of arterial aneurysm.95% of AAA are infrarenal. www.yoursurgery.com

celiac arterySMA

IMA

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Jean Kang, HMS III

Gillian Lieberman, MD

EpidemiologyEpidemiology

Incidence of ~36 per 100,000.Up to 9% of persons > 65 yo.

Natural history of AAA is progressive expansion and eventual rupture.Overall mortality rate after rupture 78-94%.Ruptured AAA results in 15,000 deaths per year in the US.

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Jean Kang, HMS III

Gillian Lieberman, MD

Risk of RuptureRisk of RuptureSize of the aneurysmIncreased in women, patients with HTN and COPD.

When to offer AAA repair based on 1) Rupture risk

< 4 cm – follow w/ US q 6 mo4-5.5 cm – additional info needed> 5.5 cm or expands > 0.5 cm in 6 mo – repair indicated

2) Life expectancy3) Operative Risk

Hallett J 2000

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Jean Kang, HMS III

Gillian Lieberman, MD

Endovascular SurgeryEndovascular Surgery

First introduced by Parodi and associates in 1991.Less invasive than open surgery.– 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.

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Jean Kang, HMS III

Gillian Lieberman, MD

Endovascular Surgery (Endovascular Surgery (con’tcon’t))

AneuRx stent-graft Ancure endograft

hooks of the proximal attachment systemYusuf 2000

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Jean Kang, HMS III

Gillian Lieberman, MD

Endovascular Surgery (Endovascular Surgery (con’tcon’t))

Yusuf 2000

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Jean Kang, HMS III

Gillian Lieberman, MD

Role of Radiologic Imaging in Role of Radiologic Imaging in Endovascular SurgeryEndovascular Surgery

Preoperative evaluationIntraoperative imaging– Proper endograft placement– A road map for orientation during procedure

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

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Jean Kang, HMS III

Gillian Lieberman, MD

Preoperative EvaluationPreoperative Evaluation

Determine the feasibility of an endograft.– Anatomy– Quality of the vessel wall

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 Preoperative Evaluation ((con’tcon’t))

proximal neck

aortic aneurysm

distal attachment sites Distal attachment

site may not be suitable.

Proximal neck may be too short.

Yusuf 2000

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Jean Kang, HMS III

Gillian Lieberman, MD

Preoperative ImagingPreoperative Imaging

CT with 3-D ReconstructionAngiographyMRAIVUS

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Jean Kang, HMS III

Gillian Lieberman, MD

Spiral CT with 3Spiral CT with 3--D D ReconstructionReconstruction

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 3Spiral CT with 3--D Reconstruction D Reconstruction ((con’tcon’t))

3D reconstruction allows accurate length and diameter measurements.

slice reformatted perpendicular to the

vessel

a conventional axial CT slice

Fillinger 1999

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Jean Kang, HMS III

Gillian Lieberman, MD

Spiral CT with 3Spiral CT with 3--D Reconstruction D Reconstruction ((con’tcon’t))

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: CTOur Patient: CT

CT without contrast CT with contrast

calcification

BIDMC PACS

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Jean Kang, HMS III

Gillian Lieberman, MD

Our Patient: CT (Our Patient: CT (con’tcon’t))

right renal artery

SMA

left renal artery

at the level of the right renal artery

15mm below the right renal artery

BIDMC PACS

s/p cholecystectomy

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Jean Kang, HMS III

Gillian Lieberman, MD

Our Patient: CT (Our Patient: CT (con’tcon’t))

BIDMC PACS

Maximum diameter = 52 x 54.2 mm Bifurcation of the aorta

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Jean Kang, HMS III

Gillian Lieberman, MD

Our Patient: CT Our Patient: CT 33--D Reconstruction (MIP)D Reconstruction (MIP)

Maximum intensity projection

3-D imaging technique that permits separation of the enhanced lumen from high attenuation structures within the vessel wall

Can readily detect calcification in the vessel wall

Poor depiction of vessels that overlap each other– Circumvent this problem by generating multiple MIPs

that rotate about an imaginary axis

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Jean Kang, HMS III

Gillian Lieberman, MD

Our Patient: CT Our Patient: CT 33--D Reconstruction (MIP)D Reconstruction (MIP)

BIDMC PACS

calcifications

poor depiction of vessels that overlap

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Jean Kang, HMS III

Gillian Lieberman, MD

Our Patient: CT Our Patient: CT 33--D Reconstruction (MIP)D Reconstruction (MIP)

BIDMC PACS

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Jean Kang, HMS III

Gillian Lieberman, MD

AngiographyAngiography

Used as part of preoperative evaluationSensitive for evaluating occlusive diseaseOnly the inner lumen is imaged– Cannot evaluate the true lumen diameter,

extent of thrombus, plaque and calcification2-D projection of a 3-D structureInvasive

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Jean Kang, HMS III

Gillian Lieberman, MD

Angiography (Angiography (con’tcon’t))

Fillinger 1999

Angiogram 3-D reconstruction from CT data

calcified plaque

noncalcified plaque and a thrombus

•Angiography may underestimate the true diameter of the aneurysm.

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Jean Kang, HMS III

Gillian Lieberman, MD

Angiography (Angiography (con’tcon’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: AngiogramOur Patient: Angiogram

BIDMC PACS

calibrated catheter

frontal view lateral view

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Jean Kang, HMS III

Gillian Lieberman, MD

MRAMRAPoorer resolution compared to CTPatient discomfort, contraindicationsCostReserved for patients with severe renal insufficiency

IVUSIVUSOperator dependentInvasiveExcellent for post op completion studies to evaluate

graft approximationgraft stenosis

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Jean Kang, HMS III

Gillian Lieberman, MD

Our Patient: Preoperative Our Patient: Preoperative Evaluation SummaryEvaluation Summary

“Fusiform infrarenal abdominal aortic aneurysm with diameter of 52 x 52mm and length of 12.5cm”“Moderate calcification of the aorta”“Good length of infrarenal abdmonial aortic neck”“Without evidence of iliac or aortic stenotic disease”

Our patient underwent endovascular repair of AAA…

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Jean Kang, HMS III

Gillian Lieberman, MD

Our Patient: Endovascular RepairOur Patient: Endovascular Repair

BIDMC PACS

preoperative angiogram

postoperative angiogram

proximal graft attachment site

distal graft attachment sites

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Jean Kang, HMS III

Gillian Lieberman, MD

Our Patient: Postoperative CTOur Patient: Postoperative CT

BIDMC PACS

thrombus within the aneurysm sac

iv contrast within the endograft

axial view

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Jean Kang, HMS III

Gillian Lieberman, MD

Our Patient: Postoperative CTOur Patient: Postoperative CT

BIDMC PACS

3D reconstruction

proximal attachment site

thrombus within the aneurysm sac

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Jean Kang, HMS III

Gillian Lieberman, MD

In SummaryIn Summary

Radiologic imaging plays an important role in preoperative, intraoperative, and postoperative evaluation for endovascular repair.

Preoperatively, CT with 3-D reconstruction and angiography are used to – assess suitability for endovascular repair and– measure endograft dimensions

Accurate assessment is essential in order to avoid any complications.

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Jean Kang, HMS III

Gillian Lieberman, MD

ReferencesReferencesBrink, 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 Proceedings2000; 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 EndoluminalAneurysm 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.comwww.yoursurgery.com

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Jean Kang, HMS III

Gillian Lieberman, MD

AcknowledgementsAcknowledgements

Matthew Spencer, MDDaniel Saurborn, MDGillian Lieberman, MDPamela LepkowskiLarry Barbaras and Cara Lyn D’amour