A
• Stenosis of the CIA
• Unilateral or bilateral single ≤3 cm stenosis of EIA
B
• Single ≤3 cm stenosis of infrarenal aorta
• Unilateral CIA occlusion
• Unilateral single or multiple EIA stenoses with a total length of 3–10 cm without involvement of the CFA
• Unilateral EIA occlusion without IIA or CFA involvement
C
• Bilateral CIA occlusion
• Bilateral single or multiple EIA stenoses with a total length of 3–10 cm without involvement of the CFA
• Unilateral EIA stenosis extending into the CFA
• Unilateral EIA occlusion extending into the IIA or CFA
• Heavily calcified unilateral EIA occlusion
D
• Infrarenal aortoiliac occlusion
• Diffuse aortic and biiliac disease
• Multiple stenosis of the a unilateral CIA, EIA, CFA
• Unilateral CIA and EIA occlusion
• Bilateral EIA occlusion
• Iliac stenosis in patients with abdominal aortic aneurysm requiring open repair or other lesions demanding open aortic or iliac repair
There is a subset of patients with aortoiliac occlusive disease who have small arteries, the so-called hypoplastic aortoiliac syndrome. This typically affects younger women with associated atherosclerotic disease [2].
Diagnosis
Physical Examination
Physical examination can be very helpful in localizing disease in patients with symptomatic lower extremity occlusive disease. The absence of normal femoral pulses indicates an inflow stenosis or occlusion. Bilaterally diminished femoral pulses could indicate aortic and/or bilateral iliac occlusive disease while the presence of a normal femoral pulse on one side would point to a more severe unilateral iliac process. Palpation of pulses can sometimes be misleading, though, as some patients with significant aortoiliac occlusive disease may have such well-developed collaterals that a palpable pulse is present even distal to an occlusion. As with the initial evaluation of any patient with symptomatic PAD, a complete evaluation of upper and lower extremity pulses should occur routinely.
Inspection of the extremities for signs of tissue loss, dependent rubor, or concomitant venous disease is also part of a complete evaluation.
Imaging
Vascular Lab
1.
Segmental pressures can provide objective evidence of disease in the inflow segment. A decrease in pressure of 20 mmHg or more between the brachial artery and the thigh cuffs would indicate a hemodynamically significant stenosis. This could be present unilaterally or bilaterally, offering a clue to distribution of disease. A segmental pressure study with additional reductions in pressure between the thigh and calf or ankle segments would indicate multilevel disease.
A normal resting study does not rule out significant arterial stenosis, and the vascular lab technologist can exercise a patient with typical symptoms of claudication and a normal resting study to detect a drop in pressure [3].
2.
Arterial Duplex can be a helpful adjunct in the initial evaluation of a patient with any lower extremity symptoms. Best performed while a patient is fasting, an aortoiliac duplex can often detect hemodynamically significant stenoses or occlusions. The presence of aneurysm or ectasia, complex atheromatous plaque, or mobile thrombus can also be detected as well as the presence of concomitant common femoral artery disease. This can be helpful information if one is contemplating invasive angiography for further diagnostic evaluation or intervention.
Computed Tomography Angiography
CT angiography can be diagnostic and greatly aid in treatment planning. The aortoiliac diameters, extent of calcification, and presence of mural thrombus or concomitant ectasia can help with choosing the best method of revascularization. This is often the preferred imaging test if one does not think an endovascular approach is indicated.
Angiography
Angiography is the preferred imaging test if endovascular intervention is planned, as it can be done at the same time as diagnostic imaging. A complete initial exam should include an abdominal aortogram with imaging of the aorta from renal arteries inferiorly and oblique views of the pelvis if required for visualization of disease relative to the origins of the hypogastric arteries. Bilateral runoff imaging should also be performed to the feet. This will both evaluate for concomitant infrainguinal disease and serve as a baseline to later assess for embolic complications of intervention that may require treatment.
Management
Direct Reconstruction
Aortobifemoral Bypass
Aortobifemoral bypass (ABF) has traditionally been considered the standard for the treatment of aortoiliac occlusive disease. Long-term patency rates have exceeded 75–90 %, depending on the series [4–6]. Age of patient has been well-established as inversely correlating with both primary and secondary patency [4, 6]. Five-year primary patency after ABF has been reported as 66 ± 8 % in patients younger than 50 years of age and as greater than 96 ± 2 % for those older than 60 years of age [6]. Use of autogenous superficial femoral vein as a conduit has been shown to augment the patency in this younger group of patients but at the expense of longer operating time and increased need for lower extremity fasciotomies [7]. Most surgeons choose either Dacron or ring-reinforced PTFE for conduit.
The options for the proximal graft configuration are an end-to-end or end-to-side aortic anastomosis. The classic situation where an end-to-side proximal anastomosis is routinely indicated involves a patient with bilateral external iliac artery occlusions and patent common iliac arteries. With this anatomy, perfusion of the hypogastric arteries is only possible with an end-to-side proximal anastomosis, preserving important pelvic blood flow. Situations where an end-to-end aortic anastomosis is preferable include patients with concomitant infrarenal aortic or iliac aneurysmal disease or atheromatous plaque or mural thrombus thought to be a source of peripheral embolization.
The surgical approach for aortobifemoral bypass generally involves making the femoral incisions first, either longitudinally or transversely. Once vascular control is obtained in the groins, the midline abdominal incision is made and the standard approach to the aorta is undertaken. There may be increased collaterals in the abdominal wall and retroperitoneum compared to a patient with aneurysmal pathology.
Each tunnel should be created by initially using one’s fingers to gently create a plane just anterior to the iliac arteries, care being taken to avoid ureteral or venous injury. Once the tunnel is digitally created, an aortic clamp can be passed along one’s hand to allow for placement of an umbilical tape through the tunnel on each side. The patient should be fully heparinized. In general, the aortic pathology extends close to the renal arteries, and so proximal control should be obtained close to the renal arteries. Separate vascular control of each renal artery with vessel loops may be required for protection against embolization. If there is thrombus extending to the renal orifices as seen in an aortic occlusion, suprarenal control should also be obtained and the suprarenal clamp briefly released to “flush” out the thrombus and allow for subsequent placement of the clamp more distally. In this situation an end-to-end anastomosis is appropriate. Distal control can often be obtained in the aorta itself and avoid dissection in the pelvis. Occasionally a sidebiting clamp can be applied to the aorta and obviate the need for two separate clamps. In a stiff, calcified aorta, a portion of aortic wall can be excised to allow for better visualization of the lumen.
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