Residency · Residency · Vascular Surgery

Aortoiliac Occlusive Disease: Evaluation and Surgical Options

Overview

Aortoiliac occlusive disease is characterized by atherosclerotic narrowing or blockage of the infrarenal aorta and iliac arteries. It accounts for approximately 30% of symptomatic peripheral arterial disease (PAD). The classic clinical presentation, known as Leriche syndrome, includes a triad of bilateral hip or buttock claudication, absent femoral pulses, and erectile dysfunction. The disease spectrum varies widely, ranging from focal stenosis of the iliac arteries to diffuse occlusion involving the entire aortoiliac segment. Patients with this condition frequently have concomitant atherosclerosis affecting the coronary and cerebrovascular circulations.

Anatomy and Disease Patterns

Relevant Anatomy

The infrarenal aorta bifurcates at the level of the L4 vertebra into the common iliac arteries. Each common iliac artery then divides into the external and internal (hypogastric) iliac arteries. The external iliac artery continues below the inguinal ligament as the common femoral artery, supplying the lower extremity. The internal iliac artery primarily supplies the pelvis and serves as an important collateral pathway in cases of aortoiliac occlusion.

Patterns of Disease

Aortoiliac occlusive disease can be classified into three main types based on the extent and distribution of arterial involvement. Type I disease is confined to the distal aorta and common iliac arteries and accounts for 5-10% of cases. Type II involves diffuse disease of the distal aorta and iliac arteries, representing about 25% of cases. Type III, the most common pattern (65%), combines aortoiliac disease with infrainguinal arterial involvement.

TASC II Classification (Aortoiliac)

The Trans-Atlantic Inter-Society Consensus (TASC) II classification stratifies aortoiliac lesions by severity and guides treatment decisions. TASC A lesions include unilateral or bilateral common iliac artery (CIA) stenosis and single short external iliac artery (EIA) stenosis. TASC B lesions encompass short infrarenal aortic stenosis, unilateral CIA occlusion, and single or multiple EIA stenoses. TASC C lesions involve bilateral CIA occlusion, bilateral EIA stenosis, or unilateral EIA occlusion. TASC D lesions represent the most severe disease, including diffuse infrarenal aortic occlusion, diffuse bilateral CIA and EIA disease, unilateral CIA and EIA occlusion, or bilateral EIA occlusion.

<image>Anatomical diagram illustrating TASC II classification of aortoiliac lesions (Types A through D) with corresponding arterial anatomy showing progressive disease severity from focal stenosis to diffuse occlusion</image>

Clinical Presentation

Patients with aortoiliac occlusive disease typically present with claudication affecting the buttocks, hips, and thighs, which is often bilateral in cases of aortic involvement. Erectile dysfunction is a common symptom resulting from reduced blood flow through the hypogastric arteries. A hallmark physical finding is diminished or absent femoral pulses. Less commonly, patients may develop blue toe syndrome due to atheroembolism. If the disease progresses, rest pain or tissue loss may occur, indicating critical limb-threatening ischemia.

Diagnostic Evaluation

Noninvasive Testing

Noninvasive assessment begins with the ankle-brachial index (ABI), which is typically reduced bilaterally in aortic disease. Segmental pressure measurements reveal a pressure drop at the thigh level. Pulse volume recordings (PVRs) demonstrate dampened waveforms at the thigh and distal levels. Duplex ultrasound is a useful imaging modality but can be limited by patient body habitus and bowel gas interference.

Cross-Sectional Imaging

Computed tomography (CT) angiography is considered the gold standard for preoperative planning. It allows detailed evaluation of aortic calcification, vessel diameter, and the extent of occlusion. CT angiography also assesses iliac artery tortuosity and landing zones for interventions, as well as involvement of the renal and mesenteric arteries. Magnetic resonance (MR) angiography serves as an alternative in patients with renal insufficiency, although gadolinium contrast should be avoided if the estimated glomerular filtration rate (eGFR) is below 30 mL/min.

Catheter Angiography

Catheter angiography remains the definitive test for hemodynamic assessment. It measures pressure gradients across iliac stenoses, with gradients greater than 10 mmHg at rest or over 15 mmHg after vasodilator challenge considered significant. This procedure is often performed concurrently with planned endovascular interventions.

Endovascular Treatment

Iliac Artery Angioplasty and Stenting

Primary stenting is the standard of care for iliac artery lesions, preferred over provisional stenting following angioplasty alone. Endovascular treatment yields excellent outcomes for TASC A and B lesions and is increasingly applied to TASC C lesions with favorable intermediate-term results.

Techniques

Kissing stents involve simultaneous bilateral stenting of the common iliac arteries to preserve the aortic bifurcation. Deploying stents simultaneously prevents contralateral plaque shift. Both self-expanding and balloon-expandable stents are used depending on lesion characteristics. Covered stents, or stent grafts, have demonstrated superiority over bare metal stents for complex iliac lesions, as evidenced by the COBEST trial. For diffuse aortoiliac disease, the covered endovascular reconstruction of the aortic bifurcation (CERAB) technique employs specialized aortic bifurcation devices to restore flow.

Results

Technical success rates for iliac artery stenting exceed 95%. Primary patency rates at five years are approximately 70-80% for common iliac artery stenting and slightly lower, around 65-75%, for external iliac artery stenting. Complications include access site problems, distal embolization, and vessel rupture, occurring in 1-2% of cases.

<image>Fluoroscopic image demonstrating kissing stent deployment at the aortic bifurcation for bilateral common iliac artery stenosis, with guidewires and delivery systems visible in both iliac systems</image>

Open Surgical Options

Aortobifemoral Bypass (ABF)

The aortobifemoral bypass remains the gold standard open surgical procedure for diffuse aortoiliac occlusive disease. Indications for ABF include TASC C and D lesions, failed endovascular therapy, concurrent need for femoral artery reconstruction, and young, active patients seeking maximal long-term durability.

Technique

The procedure is performed via a midline transperitoneal or left retroperitoneal approach. The infrarenal aorta is clamped, with suprarenal clamping reserved for cases requiring a more proximal anastomosis. The proximal anastomosis is preferably end-to-end, although end-to-side anastomosis may be used. A bifurcated Dacron or polytetrafluoroethylene (PTFE) graft, typically sized 14x7 or 16x8 mm, is used. The graft limbs are tunneled retroperitoneally to the femoral arteries, where bilateral femoral anastomoses are created in a hood configuration.

Results

Primary patency rates for ABF are excellent, ranging from 85-90% at five years and 70-80% at ten years. Perioperative mortality ranges from 2-5%, while major morbidity, including cardiac events, pulmonary complications, and renal injury, occurs in 15-20% of patients.

Iliofemoral Endarterectomy

Iliofemoral endarterectomy is suitable for localized Type I disease. It can be performed using eversion or open techniques with patch angioplasty. However, this procedure is less commonly performed in the modern era due to advances in endovascular therapy.

Extra-Anatomic Bypasses

Extra-anatomic bypasses serve as alternatives for patients unfit for ABF. The axillobifemoral bypass is indicated in high-risk patients and has a five-year patency of 50-70%, which is inferior to ABF but associated with lower perioperative mortality and morbidity. The femorofemoral bypass is used for unilateral iliac occlusion when adequate inflow exists from the contralateral iliac artery. Its five-year patency ranges from 70-80%, but success depends on sufficient donor iliac artery flow.

<image>Intraoperative view of aortobifemoral bypass with bifurcated Dacron graft showing proximal end-to-end aortic anastomosis and bilateral retroperitoneal limb tunneling to femoral arteries</image>

Hybrid Procedures

Hybrid procedures combine iliac artery stenting with femoral endarterectomy in a single operative setting. This approach is particularly useful for multilevel disease and reduces physiologic stress compared to full open reconstruction. Hybrid techniques are increasingly employed in high-risk patients who may not tolerate extensive surgery.

Controversies

There is ongoing debate regarding the optimal treatment for TASC C and D lesions. While open ABF has traditionally been the first-line therapy, improving endovascular techniques challenge this paradigm. The CERAB technique expands endovascular options for diffuse aortoiliac disease, but long-term durability data for covered stents in the iliac position remain limited. Hybrid approaches offer a middle ground, balancing invasiveness and durability.

Complications of Aortic Surgery

Early complications following aortic surgery include hemorrhage, myocardial infarction, renal injury, bowel ischemia, distal embolization, and sexual dysfunction due to sympathetic nerve injury. Late complications encompass graft limb thrombosis, anastomotic pseudoaneurysm, aortoenteric fistula, and graft infection. Aortoenteric fistula is a particularly serious complication, often presenting initially with a herald bleed followed by massive gastrointestinal hemorrhage. A high index of suspicion is essential in any patient with prior aortic surgery who develops GI bleeding.

Clinical Pearls

Careful examination of femoral pulses is critical, as absent femoral pulses strongly suggest aortoiliac disease and should be addressed before any infrainguinal intervention. For aortobifemoral bypass, an end-to-end proximal anastomosis is preferred over end-to-side to reduce competitive flow issues and the risk of distal aortic stump syndrome. Preservation of at least one hypogastric artery is important to maintain pelvic perfusion and reduce the risk of buttock claudication, erectile dysfunction, and colonic ischemia. When considering femorofemoral bypass, the quality of the donor iliac artery must be assessed to ensure adequate inflow. In young patients under 50 years old, unusual causes of aortoiliac disease such as mid-aortic syndrome, Takayasu arteritis, or radiation arteritis should be considered.

References

• Norgren L, et al. Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II). J Vasc Surg. 2007;45(Suppl S):S5-S67.
• Mwipatayi BP, et al. Covered vs. bare expandable stents for aortoiliac occlusive disease (COBEST). J Vasc Surg. 2016;64(6):1561-1570.
• Chiu KW, et al. Review of direct anatomical open surgical management of atherosclerotic aorto-iliac occlusive disease. Eur J Vasc Endovasc Surg. 2010;39(4):460-471.
• Kashyap VS, et al. The management of severe aortoiliac occlusive disease: endovascular therapy vs. open reconstruction. J Vasc Surg. 2008;48(6):1451-1457.
• Grimme E, et al. Aortobifemoral bypass: gold standard or outdated procedure? Ann Vasc Surg. 2020;64:344-351.

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