more frequently female, and typically have a normal life expectancy.12,13 These patients usually present

with complaints of disabling claudication in the buttocks, hips, and thighs. Such localized disease may

be amenable to percutaneous transluminal angioplasty (PTA) or, as was sometimes practiced in the past,

aortoiliac endarterectomy.

Type II aortoiliac disease is more extensive and more common; the atherosclerotic plaque extends

distally into the external iliac arteries and may reach the common femoral bifurcations. Such patients

experience worse claudication than patients with more localized disease and may present with CLI. They

are usually men, present on average a decade later in life (60s and 70s), than patients with type I

disease, and tend to have diabetes, hypertension, and concomitant cerebrovascular, coronary, and

visceral atherosclerosis.12 As a result, these patients have a reduced life expectancy.13,14

Figure 92-3. Digital atheroembolization progressed to gangrene.

Type III disease is a combination of aortoiliac and femoropopliteal and/or tibial disease. These

patients with multilevel disease are usually older than those in the other two groups and present more

frequently with symptoms of CLI.12

One other pattern worthy of mention is aortoiliac hypoplasia. The term small aortic syndrome or

hypoplastic aortic syndrome may also be used. This pattern is encountered in young to middle-aged

women who smoke cigarettes. The infrarenal aorta and iliac arteries are unusually small in caliber and

hence prone to significant narrowing, even with modest disease. Operative treatment of such patients

can be particularly challenging.15

In response to the rapidly evolving patterns of treatment of AIOD and the increasingly prominent role

played by endovascular methods, the Trans-Atlantic Inter-Society Consensus for the Management of

PAD (TASC II) has classified AIOD into four types, A through D (Table 92-1).16 The value of this

classification derives from its use as a template for reporting standards and as a guideline to help direct

treatment decisions. Patients with focal disease (TASC II types A and B) usually benefit from

endovascular interventions, while those with more advanced disease (TASC II types C and D) are

usually best managed with open surgical revascularization. However, evolving endovascular approaches

are now being applied to these advanced lesions as well, with acceptable results.17 This is especially

true for high-risk patients with TASC C and D disease presenting with CLI, who frequently have

significant comorbidities, such as severe chronic obstructive pulmonary disease, nonreconstructible

coronary artery disease, or a low cardiac ejection fraction. Although this approach may lead to less

durable results than open surgical options, it is less morbid. To simplify the most current widely

accepted strategy, the surgeon should apply endovascular treatment methods for type A and B patients,

and lean toward open surgery for type C and D disease.

DIAGNOSIS

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In most cases, diagnosis of significant AIOD and its severity can be made on the basis of history and

physical examination alone. A clinical diagnosis, however, should be supplemented by noninvasive

vascular testing. Such tests provide valuable information by confirming the presence of disease,

assessing the degree of ischemia, objectively documenting the arterial segment(s) involved, and

establishing a baseline from which the patient can be followed and appropriate interventions planned.

Treatment results can be assessed by repeated testing. Such information is particularly useful in a

patient with an equivocal history or physical examination. Formal imaging studies (CTA, MRA, and

arteriography) are usually reserved for those patients considered for intervention.

Noninvasive Vascular Testing

Segmental Doppler-derived pressure measurements or pulse volume recordings are useful for

demonstrating the physiologic significance of disease and can help localize hemodynamically significant

lesions. Measurement of systolic arterial pressures at different levels of the lower extremity with a

continuous wave Doppler flow probe is the simplest and most useful noninvasive method to assess

arterial occlusive disease. The ratio of the ankle systolic pressure (measured at either the dorsalis pedis

or the posterior tibial artery) to the brachial systolic pressure (using the higher of the two brachial

pressures) is the ankle-brachial index (ABI), or pressure ratio, and is a good measure of the degree of

ischemia present. Normal ABIs are generally equal to or slightly greater than 1.0 (Fig. 92-4). Peripheral

arterial disease is designated when the ABI is ≤0.95. Patients with claudication usually have ABIs

ranging from 0.50 to 0.90, whereas patients with rest pain, tissue loss, or gangrene have ABIs of <0.50.

Some patients with claudication, as a result of excellent collaterals, may have ABI of >1.0 at rest.

Table 92-1 TASC II Classification

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Figure 92-4. Segmental pressure measurements typical of normal results (A) and aortoiliac occlusive disease (B).

Determination of limb systolic pressures at different locations (with the “four-cuff” technique, where

pressures are measured at the upper thigh, lower thigh, calf, and ankle) provides information

concerning which arterial segments are involved with occlusive disease (Fig. 92-4) and helps define the

presence of inflow artery disease, outflow (runoff artery) disease, or a combination of the two. A

pressure drop of more than 20 mm Hg between adjacent levels indicates significant disease within the

intervening arterial segment. A reduced upper thigh pressure signifies occlusive disease in the aortoiliac

or common femoral segments.18

In patients with extensive calcification in the walls of the tibial arteries (as is frequently seen in

diabetes mellitus or end-stage renal disease), the ankle pressures may not be interpretable because the

vessels are too “stiff” to be properly compressed by the externally applied cuff. In this situation, the

pressure in the digital arteries of the great toe can be measured, since these small vessels are generally

spared calcification. A toe pressure of less than 30 mm Hg indicates severe ischemia.19 Inspection of the

Doppler-derived arterial waveforms can provide additional information.

Patients with claudication occasionally have normal or nearly normal ABIs. As described previously,

in such cases the arterial stenosis is not severe enough to cause a pressure drop in the limb at rest but

does produce a significant hemodynamic change under conditions of higher flow rates when the distal

vasculature dilates, as occurs with exercise. When the distal pressure drops because of vascular dilation,

the stenosis prevents increased blood flow into the extremity so that a significant distal pressure drop

results. The classic treadmill test involves walking on a treadmill at 1.5 miles per hour at a 14% incline

for as long as the patient can go, up to 5 minutes. ABIs are measured before and after a treadmill

exercise; a drop of 15% or more in the ABI following exercise is indicative of a hemodynamically

significant occlusive disease.18

Duplex scanning of the aorta and iliac arteries has been advocated by some as a noninvasive

diagnostic tool. Accurate imaging of the abdominal arteries, however, is difficult because of their deep

retroperitoneal and pelvic locations, which can be further degraded by body habitus and overlying

bowel gas. These problems have limited the widespread use of this modality.20 Arteriography, CTA, and

MRA may be used for diagnosis, but are usually performed when interventional therapy is

contemplated, and are, therefore, discussed later.

Differential Diagnosis

The diagnosis of AIOD is usually straightforward, but occasional diagnostic difficulty may arise when

other causes of lower extremity pain are present. Irritation of lumbosacral nerve roots by spinal stenosis

or intervertebral disc herniation may cause buttock and leg pain that is associated with activity. Such

symptoms (neurogenic claudication), however, usually cannot be reproduced at the same level of

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activity, frequently occur when the patient is standing, and are relieved only by sitting or lying down.

In addition, the pain is usually in a classic sciatic distribution.

Degenerative arthritis of the hip joints may produce similar buttock, hip, and referred thigh pain.

There is usually a history of morning stiffness that progressively improves over the course of the day.

Physical examination typically reveals tenderness directly over the hip joint that is exacerbated by

moving the joint.

Algorithm 92-1. Patient with symptomatic aortoiliac occlusive disease.

Peripheral neuropathy, particularly that associated with diabetes mellitus, may masquerade as

ischemic rest pain.

In all these situations, segmental limb pressure measurements, with or without stress testing, can be

helpful in determining the contribution of arterial occlusive disease to the patient’s symptoms.

TREATMENT

The aims of therapy in AIOD are to relieve symptoms and, in cases of CLI, to prevent limb loss

(Algorithm 92-1). Medical therapy should be instituted in all patients with atherosclerotic disease but is

insufficient as sole therapy in patients with limb-threatening ischemia.

Medical Therapy

3 Atherosclerosis is a systemic disease. Medical therapy is, therefore, key to reducing the risk associated

with cardiovascular death in these patients. Risk factor modification, including treatment of diabetes

mellitus, control of hypertension, and treatment of hyperlipidemia, and finally modification of lifestyle

including cessation of smoking, diet, and exercise, are perhaps the most important components of the

care of patients with atherosclerotic disease. Although risk factor control will not reverse the

atherosclerotic process, it does limit disease progression; furthermore, some data indicate that smoking

cessation lessens the severity of symptoms in many patients.21

Smoking Cessation

4 Smoking is associated with a subclinical inflammatory reaction.22 The degree of damage caused by

smoking is directly related to the amount of tobacco consumed. The TASC II consensus recommends

that: “All patients who are smokers or former smokers should be asked about the status of tobacco use

at every visit. All patients should be strongly advised to stop smoking by their physicians. All patients

should be offered pharmacotherapy, behavior modification, referral to a smoking cessation program,

and counseling.”14 Smoking cessation alters the progression of the atherosclerotic process and may even

reduce the severity of claudication23,24; Furthermore, it is an important step to reduce postoperative

complications.25,26

Exercise

Supervised exercise programs have been consistently demonstrated to improve walking time and

walking distance.27 Home and community-based therapy are effective for improving walking tolerance

but are less effective than formal supervised exercise programs and are associated with a high dropout

rate, underscoring the need for ongoing psychological support.22,23,28 Outcomes of supervised exercise

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programs have been shown to be similar and longer lasting than those of endovascular interventions for

mild claudication.24,25 Patients are usually advised to walk until the pain occurs, rest until the pain

subsides, and repeat the cycle, to a total of 30 minutes a day, three to five times per week. A 3- to 6-

month trial of exercise should be initiated before intervention is considered in patients with intermittent

claudication.

Diet

A well-balanced diet with low salt, low fat, and moderate amounts of added sugar intake, as per the

American Heart Association guidelines, reduces the risk of chronic diseases in general, and

cardiovascular disease in particular, and should be followed.26

Glycemic Control

The Trans-Atlantic Inter-Society Consensus (TASC II) consensus document recommends aggressive blood

glucose control, with a target A1C goal of <7.0%, and as close to 6.0% as possible.16

Antiplatelet Therapy

Some form of platelet inhibition should be considered for all atherosclerotic patients in order to reduce

the risk of myocardial infarction, stroke, and death.29 Aspirin is the agent of choice, but clopidogrel may

be used if aspirin is not tolerated. The effectiveness of antiplatelet therapy in reducing symptoms of

claudication is not yet established; however, the risk of PAD progression requiring revascularization is

significantly reduced by antiplatelet therapy, compared with placebo.30 Adding aspirin to clopidogrel

does not reduce major vascular events. However, the risk of major life-threatening bleeding is

increased.31

Antihypertensive Therapy

Antihypertensive therapy reduces mortality from atherosclerotic cardiovascular disease. It is, therefore,

recommended in the TASC II consensus document, despite the lack of data substantiating that

antihypertensive therapy alters the progression of PAD.16

Lipid-Lowering Therapy

Lipid-lowering therapy with at least a moderate dose of a statin medication is recommended for all

patients with atherosclerotic cardiovascular disease, irrespective of the baseline low-density lipoprotein–

cholesterol. Lipid-lowering therapy reduced disease progression (as measured by arteriography), helped

alleviate symptoms, and improved total walking times and pain-free walking distance.32

Other Pharmacologic Therapy

Cilostazol and naftidrofuryl can be valuable adjuncts in selected patients with severe lifestyle-limiting

claudication.33,34 A therapeutic trial (3 to 6 months) may be tried. Although the mechanisms of action of

these agents are unclear, a modest but significant reduction in claudication symptoms has been shown in

controlled trials. Benefit has not been firmly established for other agents.

Indications for Revascularization

Revascularization is clearly indicated in patients with CLI; without intervention, these patients can

progress to limb loss in a fairly short period of time. At 1 year following onset of CLI symptoms, it is

estimated that 25% of patients will lose their limb, 25% will suffer a cardiovascular death, and 50% will

be alive with their limbs intact.35,36 Per year, 1% to 2% of patients with claudication will progress to

CLI.36

Patients with significant or repetitive atheroembolism from an aortoiliac source represent a group

that clearly benefits from early operative intervention. Removal or bypass of the culprit lesion(s)

eliminates the risk for further macro- and microembolism.

The treatment of patients with claudication secondary to AIOD remains somewhat controversial and

must be individualized. Patients with mild to moderate symptoms can usually be treated medically with

satisfactory results, while patients with severe, disabling, and lifestyle-limiting symptoms of

claudication can benefit from revascularization therapy.

Preintervention Imaging Studies

Once a decision has been made to proceed with revascularization therapy, imaging studies are

paramount for developing a treatment strategy.

2631

Figure 92-5. CTA 3D reconstruction showing left iliac artery chronic total occlusion (red arrow).

Computed Tomographic Angiography

CTA with reformatting requires the intravenous administration of iodinated contrast material, followed

by a timed CT scan of the pertinent anatomy. The images are then processed into coronal, sagittal, and

three-dimensional image planes (Figs. 92-2, 92-5 to 92-7). For most patients, 120 mL of iodine contrast

is used (300 to 370 mg of iodine per milliliter of contrast). Sensitivity and specificity are greater than

92% and 93%, respectively, in detecting >50% stenosis. The main drawbacks of CTA are the ionizing

radiation and the use of iodinated contrast, which can cause contrast-induced nephropathy.37

Figure 92-6. A: CTA 3D reconstruction demonstrating right common iliac artery chronic total occlusion (red arrow) and severe left

common iliac artery stenosis (blue arrow). B: Abdominal aortogram redemonstrating right common iliac artery chronic total

occlusion and left common iliac artery stenosis. Note successful wire traversal of the right common iliac artery occlusion (red

arrow). C: Abdominal aortogram demonstrating successful endoluminal bilateral common iliac artery revascularization following

percutaneous balloon angioplasty and stent placement. Note the “kissing” stents in the distal aorta (red arrow).

2632

Figure 92-7. A: A midline abdominal incision and bilateral groin incisions overlying the common femoral arteries offer exposure

for performance of aortobifemoral bypass. B: This image demonstrates an end-to-end proximal aortic to graft reconstruction with

the respective graft limbs anastomosed end to side to the common femoral arteries. C: Computed tomographic angiographic

postprocessed and reformatted image demonstrating open aortobifemoral arterial reconstruction of juxtarenal aortic occlusion (see

Fig. 92-2, preoperative image) with prosthetic bifurcated graft. Note endarterectomy of aorta immediately distal to renal arteries

(red arrow), followed by proximal end-to-end anastomosis between graft and aorta (blue arrow). Distal anastomosis to femoral

arteries is performed in end to side fashion (green arrows).

Magnetic Resonance Angiography

Contrast-enhanced MRA uses intravenous administration of paramagnetic gadolinium-based agents.

With good technique, contrast-enhanced MRA has a sensitivity of 80% to 97%, and a specificity of 73%

to 96% (Fig. 92-8).38 The disadvantage of MRA is that it cannot be used in patients with metallic

implants such as pacemakers and patients with claustrophobia. Furthermore, in patients with

moderately severe renal dysfunction (glomerular filtration rate of <60 mL/min/1.72 m2), concerns for

nephrogenic systemic fibrosis secondary to gadolinium limit the use of this technology in this patient

population.39

Digital Subtraction Arteriography

Abdominal aortography, with or without demonstration of the arterial tree below the inguinal ligament

(“runoff”), is performed after a full workup is completed and may be part of the therapeutic

intervention. This procedure is most commonly performed via the femoral artery with the better pulse

by means of a retrograde Seldinger technique. When neither femoral artery is available, an upper

extremity approach may provide good access. Hemorrhage, local hematoma, pseudoaneurysm, arterial

thrombosis, or distal embolism of thrombus or atheromatous debris can occur in up to 0.8% of

diagnostic procedures and in up to 6% of therapeutic procedures.40,41 Anteroposterior views of the

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aortoiliofemoral segments demonstrate the extent of the occlusive process and the pattern of collateral

formation. Oblique views of the iliac and femoral arteries are frequently necessary to document

posterior wall plaques and stenoses at the origins of the hypogastric and deep femoral arteries. Views of

the “runoff” arteries to at least the midcalf level are required to assess the degree of associated

infrainguinal occlusive disease. In cases of CLI, visualization of the pedal circulation is also necessary. In

patients with borderline kidney function, carbon dioxide may be utilized as a contrast agent.

Figure 92-8. MRA of a patient who had an aortobifemoral bypass. Note the proximal anastomosis (thin arrow) and the distal

anastomosis (thick arrows). Also note the retrograde flow into the iliac arteries.

Occasionally, the hemodynamic effect of a stenosis or series of stenoses along an iliac arterial

segment may be difficult to determine, even with oblique views. When the significance of a stenosis

remains in question, pressures proximal and distal to the lesion(s) can be measured. A systolic pressure

gradient of more than 10 mm Hg (or a 5 mm Hg mean gradient) across the stenosis is indicative of a

hemodynamically significant lesion.42 For borderline cases, distal pressure measurements can be

obtained before and after interarterial injection of a vasodilator (e.g., 100- to 200-μg nitroglycerin or

25-mg papaverine) to simulate the hyperemic hemodynamics of exercise. A pressure drop of more than

15% systolic pressure (or around 20 mm Hg) during hyperdynamic flow simulation is considered

indicative of a hemodynamically significant stenosis.42

The information supplied by CTA, MRA, or arteriography is crucial to the success of a

revascularization procedure. In addition to providing a detailed “road map” of the exact arterial

segments involved, such imaging identifies associated anatomic variations (e.g., accessory renal

arteries) and aortic wall characteristics (e.g., extensive calcification and ulcerated plaque), which may

alter the operative approach and the conduct of the procedure. During an open revascularization

procedure, a surgeon who knows that the aortic wall just below the renal arteries is heavily diseased

with ulcerated plaque may, for example, opt to control the aorta at a more proximal level rather than

risk dislodging atheromatous debris with standard infrarenal aortic clamping. Similarly, documented

occlusive lesions in the visceral or renal arteries (e.g., a patent IMA with a large “meandering

mesenteric artery”) may best be addressed at the time of aortic reconstruction, or require particular

attention to avoid complications.

Preoperative Evaluation

Evaluation of patients for whom aortoiliac revascularization is being considered should include a careful

assessment of overall operative risk. Age per se is not a contraindication to an open aortic

reconstruction, if it is required. A less invasive procedure of more limited durability, however, may

provide a similarly excellent outcome in a patient with reduced life expectancy. Patients with significant

AIOD may have atherosclerotic occlusive disease in other vascular territories (e.g., coronary and

cerebral) that can increase their operative risk. The detection and treatment of significant coronary

artery disease is particularly important, because myocardial infarction is the leading cause of both

perioperative and late mortality. In patients with significant aortoiliac disease, more than 50% have

2634

clinical or electrocardiographic evidence of coronary disease.43 In the Coronary Artery

Revascularization Prophylaxis (CARP) trial, patients undergoing elective, open, abdominal aortic

surgery for aortoiliac occlusive or aneurysmal disease at Veterans Administration hospitals were

assessed for cardiac risk.44 At an average of 2.7 years of follow-up after the aortoiliac procedure, there

was no difference in outcome between those who underwent coronary revascularization prior to aortic

surgery and those who did not (22% of patients who underwent coronary revascularization died, vs.

23% of those treated medically, p = 0.92). Only selected patients, therefore, require cardiac

catheterization and occasional coronary angioplasty or bypass grafting before undergoing open aortic

reconstruction, and these patients need to be stratified according to risk guidelines.45

Pulmonary complications occur in 10% to 15% of patients after open aortoiliac repair,46 and lung

function should be assessed preoperatively only if clinical evaluation cannot determine that the patient

is at his or her best achievable baseline pulmonary function and that airflow obstruction has not been

optimally relieved. There is otherwise no indication for routine preoperative pulmonary function

testing, as the American College of Physicians guidelines state that routine preoperative spirometry is

not useful for predicting the risk of postoperative pulmonary complications.47 Smokers who quit more

than 4 weeks before surgery have significantly lower risk of respiratory complications and improved

wound healing.48

Choice of Revascularization Technique

A variety of surgical procedures, both endovascular and open, are available for revascularization in the

patient with AIOD. Selection depends on a number of factors, including the pattern of the occlusive

process, patient risk, surgeon experience, and patient preference.

Commonly used techniques include (a) catheter-based balloon dilation (angioplasty) with or without

luminal stenting, (b) arterial reconstruction with an anatomically placed bypass prosthesis

(aortofemoral or iliofemoral bypass), (c) arterial reconstruction with a remote (or extraanatomically

placed) bypass prosthesis (axillofemoral or bifemoral, femorofemoral, thoracofemoral bypass), (d)

aortoiliac endarterectomy, and (e) a hybrid approach encompassing a combination of endovascular and

open procedures.

Catheter-based techniques are best suited for localized lesions of the common iliac arteries. However,

it is currently being used as the main therapeutic modality for the majority of patients; it has essentially

replaced endarterectomy procedures in patients with focal AIOD. Prosthetic aortofemoral bypass is the

procedure of choice for most patients with advanced, extensive aortoiliac atherosclerosis and is still

considered the “gold standard” for aortoiliac revascularization. Femorofemoral or iliofemoral bypass

can be chosen in poor-risk patients with diffuse unilateral iliac disease, or with bilateral iliac

involvement, when the stenosis in one of the iliac arteries can be appropriately treated by balloon

angioplasty, with or without intraluminal stenting.

Axillofemoral or bifemoral bypass is reserved for the small subset of patients in whom standard aortic

reconstruction is considered too risky, either for medical reasons (usually severe pulmonary or cardiac

disease) or for technical reasons (e.g., aortic reoperations, multiple prior abdominal procedures with

dense adhesions, prior abdominal irradiation, and prosthetic graft infection). The descending thoracic

aorta can be considered as an alternative inflow source in the construction of a thoracofemoral bypass in

a low-risk patient with a “hostile” abdomen.49

Endovascular Surgical Management

5 Since the very first transarterial dilation procedures by Dotter, the development of balloon

angioplasty by Gruntzig, and the deployment of intra-arterial stents by Palmaz, PTA has become the

most commonly performed and, in some cases, the preferred therapy for iliac artery occlusive

disease.50,51 Like open operative reconstruction, PTA, when properly selected, has a high rate of success

owing to the large caliber and high rates of flow in the aortoiliac segment. The pattern of the occlusive

process and patient comorbidities are primary considerations in selecting PTA as the mode of therapy.

The best results are obtained with short, focal, stenotic lesions in the common iliac arteries (TASC A and

B).52 Patients with severe atherosclerotic lesions, complex aortoiliac stenoses, or occlusions (TASC C or

D) may also benefit more from endovascular approaches, with many series documenting excellent shortterm success. Atheromatous embolism (blue toe syndrome) from an ulcerative plaque may be treated

with placement of a stent to trap the debris, relieve the stenosis, and prevent recurrent embolism.

Description of Technique

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