Vascular - Learning Modules - CTisus.com CT Scanning

Learning Modules ❯ Vascular

CT Angiography and 3-D Imaging of Aortoiliac Occlusive Disease: Collateral Pathways in Leriche Syndrome

Introduction

Aortoiliac occlusive disease (AIOD): Atheromatous occlusion of the infrarenal abdominal aorta and/or common iliac arteries.
- Subset of peripheral arterial disease (PAD) – chronic deposition of atherosclerotic plaque.
- First described by Robert Graham in 1814 at the Royal Infirmary in Glasgow, and later by the French surgeon René Leriche in 1923.
Exact prevalence of AIOD is unknown since patients are often asymptomatic as a result of collateral pathways.
- 8 million people in the US with PAD, including 12-20% of individuals >60y.1
Symptoms include claudication of thighs, hips, and buttocks.
- Leriche syndrome – Impotence, bilateral buttocks claudication, and diminished femoral pulses in the setting of aortic occlusion.
- Acute onset of symptoms in the setting of thromboembolic disease, often with occlusion of the distal infrarenal aorta at the bifurcation point.

Goals of CT Angiography inAortoiliac Occlusive Disease

Identify the location of aortic and/or iliac vascular occlusion.
Identify concomitant atherosclerotic occlusive disease affecting visceral arteries.
Characterize pathways of collaterialization.
Identify the levels of the most proximal and distal arterial segments amenable to stent-graft placement.

Collateral Pathways –Overview

3 Major Classes of Collateral Pathways:
- 1) Systemic – Systemic
- 2) Visceral – Visceral
- 3) Systemic – Visceral
Location of occlusion determines which class of collateral pathways will develop:
- Distal occlusion (near aortic bifurcation/common iliacs) → Visceral circulatory pathways form
- Proximal occlusion (directly inferior to the renal arteries) → Systemic circulatory pathways form
Visceral-Visceral and Systemic-Visceral pathways usually occur together.

Systemic Collateral Pathways“Winslow Pathway”

“Winslow Pathway” –Risk of Complications

Several reports in the literature of lower extremity ischemia due to interruption of the internal thoracic and epigastric arteries (“Winslow Pathway”).6-8
The internal thoracic artery is commonly harvested for coronary artery bypass grafting.
- These patients often present with concomitant aortoiliac occlusive disease with extensive collateratization, including the “Winslow pathway”.
- Collateral pathways must be identified preoperatively to avoid complications.
Epigastric arteries are at risk during non-vascular abdominal surgeries.9-10

Systemic Collateral Pathways

(A) Median Sacral
(B) Sacral branches

Systemic Collateral Pathways

Systemic Collateral Pathways

Visceral Collateral Pathways

Visceral Collateral Pathways –“Arc of Riolan”

Visceral Collateral Pathways

Conclusion

Atheromatous occlusion of the infrarenal abdominal aorta and/or common iliac arteries is common in the elderly.
Patients often remain asymptomatic for an extended period of time due to formation of extensive collateral networks.
- Systemic and/or visceral collateral pathways.
CT angiography plays an important role in characterizing aortoiliac occlusive disease, including its collateral pathways.
The Radiologist must be familiar with the common and uncommon collateral pathways to guide surgical/endovascular management of patients, and avoid potential complications, such as damage to the “Winslow pathway”.

References

Allison MA, Ho E, Denenberg JO, et al. Ethnic-specific prevalence of peripheral arterial disease in the United States. Am J Prev Med. 2007;32(4):328-33.
Moore JE, Jr., Xu C, Glagov S, Zarins CK, Ku DN. Fluid wall shear stress measurements in a model of the human abdominal aorta: oscillatory behavior and relationship to atherosclerosis. Atherosclerosis. 1994;110(2):225-40.
Wooten C, Hayat M, du Plessis M, et al. Anatomical significance in aortoiliac occlusive disease. Clin Anat. 2014;27(8):1264-74.
Shakeri AB, Tubbs RS, Shoja MM, Nosratinia H, Oakes WJ. Aortic bifurcation angle as an independent risk factor for aortoiliac occlusive disease. Folia Morphol (Warsz). 2007;66(3):181-4.
Met R, Bipat S, Legemate DA, Reekers JA, Koelemay MJ. Diagnostic performance of computed tomography angiography in peripheral arterial disease: a systematic review and meta-analysis. JAMA. 2009;301(4):415-24.
Shalom F, Vunnamadala SP, Gibbs TS. An angiographic consideration prior to coronary bypass graft surgery: importance of routine selective angiography of the internal mammary artery prior to myocardial revascularization. J Invasive Cardiol. 2012;24(5):E87-9.
Ben-Dor I, Waksman R, Satler LF, et al. A further word of caution before using the internal mammary artery for coronary revascularization in patients with severe peripheral vascular disease! Catheter Cardiovasc Interv. 2010;75(2):195-201.
Yapici F, Tuygun AG, Tarhan IA, et al. Limb ischemia due to use of internal thoracic artery in coronary bypass. Asian Cardiovasc Thorac Ann. 2002;10(3):254-5.
Hodge K, Yuen J, Moursi M, Eidt JF. Critical leg ischemia resulting from interruption of collaterals by harvest of the rectus abdominis free flap: endovascular salvage. Ann Plast Surg. 2000;45(4):427-30.
Krupski WC, Sumchai A, Effeney DJ, Ehrenfeld WK. The importance of abdominal wall collateral blood vessels. Planning incisions and obtaining arteriography. Arch Surg. 1984;119(7):854-7.
Norgren L, Hiatt WR, Dormandy JA, Nehler MR, Harris KA, Fowkes FG. Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II). J Vasc Surg. 2007;45 Suppl S:S5-67.

Acknowledgements:

Sameer Ahmed MD
Siva P. Raman MD
Elliot K. Fishman MD