Aortoiliac disease

# Overview
Aortoilliac disease also known as Aorotilliac occlusive disease or Leriche Syndrome is a type of Peripheral Arterial Disease (PAD). Peripheral Arterial Disease is caused by occlusion of an artery due to atherosclerotic plaque buildup, thrombosis or embolism. PAD normally affects the distal femoral artery, but Aortoilliac disease is caused by occlusion of the infrarenal aorta and beyond. The Aorta gives off the renal branches at the L1/ L2 spine level and it branches into the Right and Left Common Illiac Arteries at the L4 spine level. Aortoilliac disease can include the Common Illiac arteries and it's branches. Depending on it's underlying cause it can present acutely or chronically.
Acute causes include thrombosis and embolism, while chronic causes include atherosclerotic plaque formation

# Classification
===Morphological Stratification of Iliac Lesions-Trans-Atlantic Intersociety Consensus Classification === 
TASC Type A iliac lesions
- Single stenosis less than 3 cm of the CIA or EIA (unilateral/bilateral)
- Single stenosis less than 3 cm of the CIA or EIA (unilateral/bilateral)
- TASC Type B iliac lesions
Single stenosis 3 to 10 cm in length, not extending into the CFA
Total of 2 stenosis less than 5 cm long in the CIA and/or EIA and not extending into the CFA
Unilateral CIA occlusion
- Single stenosis 3 to 10 cm in length, not extending into the CFA
- Total of 2 stenosis less than 5 cm long in the CIA and/or EIA and not extending into the CFA
- Unilateral CIA occlusion
- TASC Type C iliac lesions
Bilateral 5 to 10 cm long stenosis of the CIA and/or EIA, note extending into the CFA
Unilateral EIA occlusion not extending into the CFA
Unilateral EIA stenosis extending into the CFA
Bilateral CIA occlusion
- Bilateral 5 to 10 cm long stenosis of the CIA and/or EIA, note extending into the CFA
- Unilateral EIA occlusion not extending into the CFA
- Unilateral EIA stenosis extending into the CFA
- Bilateral CIA occlusion
- TASC Type D iliac lesions
Diffuse, multiple unilateral stenosis involving the CIA, EIA and CFA (usually more than 10 cm long)
Unilateral occlusion involving both the CIA and EIA
Bilateral EIA occlusions
Diffuse disease involving the aorta and both iliac arteries
Iliac stenosis in a patient with an abdominal aortic anuerysm or other lesion requiring aortic or iliac surgery
- Diffuse, multiple unilateral stenosis involving the CIA, EIA and CFA (usually more than 10 cm long)
- Unilateral occlusion involving both the CIA and EIA
- Bilateral EIA occlusions
- Diffuse disease involving the aorta and both iliac arteries
- Iliac stenosis in a patient with an abdominal aortic anuerysm or other lesion requiring aortic or iliac surgery

# Diagnosis
- MR angiography
Gadofosveset-enhanced MR angiography showed significant improvement (P < .001) compared with unenhanced MR angiography for diagnosis of clinically significant aortoiliac occlusive disease ( 50% stenosis) .
The improvement in diagnostic efficacy compared with unenhanced MR angiography was clearly demonstrated. There was an improvement in overall accuracy, sensitivity, and specificity.
- Gadofosveset-enhanced MR angiography showed significant improvement (P < .001) compared with unenhanced MR angiography for diagnosis of clinically significant aortoiliac occlusive disease ( 50% stenosis) .
- The improvement in diagnostic efficacy compared with unenhanced MR angiography was clearly demonstrated. There was an improvement in overall accuracy, sensitivity, and specificity.
- CT Angiography  
CT angiographic examination is less invasive and less expensive than conventional angiography
Improves resolution  with decreased contrast load and acquisition time without increasing radiation exposure
- CT angiographic examination is less invasive and less expensive than conventional angiography
- Improves resolution  with decreased contrast load and acquisition time without increasing radiation exposure

# Indications for Revascularization
- Relief of symptomatic lower extremity ischemia, including claudication, rest pain, ulceration or gangrene, or embolization causing blue toe syndrome
- Restoration y/o preservation of inflow to the lower extremity in the setting of pre-existing or anticipated distal bypass
- Procurement of access to more proximal vascular beds for anticipated invasive procedures. Occasionally revascularization is indicated to rescue flow-limiting dissection complicating access for other invasive procedures

# Technical Issues
- Endovascular Access
Ipsilateral femoral artery
Contralateral femoral artery
Brachial artery: In patients with flush occlusions at the aortic bifurcation
- Ipsilateral femoral artery
- Contralateral femoral artery
- Brachial artery: In patients with flush occlusions at the aortic bifurcation
- Multiple access sites may be required for successful treatment:
Bilateral femoral
Femoral/brachial
- Bilateral femoral
- Femoral/brachial

# Treatment Options

## PTA
- Endovascular treatment of iliac stenoses
High technical success rates
Low morbidity.
- High technical success rates
- Low morbidity.
- Iliac PTA/stenting
High rates of patency
Improvement in functional outcome for the individual patient
- High rates of patency
- Improvement in functional outcome for the individual patient
- Stent placement
Balloon expandable stent: Useful in Ostial Lesions
Greater radial force
Allow greater precision  for placement
Self-expandable stent
Longer lesions in which the proximal vessel maybe several millimeters larger than the distal vessel
Used predominantly in  common iliac artery orificial occlusions
- Balloon expandable stent: Useful in Ostial Lesions
Greater radial force
Allow greater precision  for placement
- Greater radial force
- Allow greater precision  for placement
- Self-expandable stent
Longer lesions in which the proximal vessel maybe several millimeters larger than the distal vessel
Used predominantly in  common iliac artery orificial occlusions
- Longer lesions in which the proximal vessel maybe several millimeters larger than the distal vessel
- Used predominantly in  common iliac artery orificial occlusions

## Surgical

# Complications
- Intraoperative complications
- Dissection
- Extravasation
- Arterial rupture
- Postoperative complications
- Pseudoaneurysm formation at the access site
- Distal embolization
- Hematoma

# Prognosis
- Ideal Iliac PTA Lesions
Stenotic lesion
Non-calcified
Discrete (< 3cm)
Patent run  off vessels (> 2)
Non- diabetic patients
- Stenotic lesion
- Non-calcified
- Discrete (< 3cm)
- Patent run  off vessels (> 2)
- Non- diabetic patients
- Predictors of long-term failure
Clinical status: CLI vs claudicant
Smoking
Women?
Vessel diameter < 8mm
Outflow status
Lack of antiplatelet regimen
Number of stents
Occlusion vs. stenosis
- Clinical status: CLI vs claudicant
- Smoking
- Women?
- Vessel diameter < 8mm
- Outflow status
- Lack of antiplatelet regimen
- Number of stents
- Occlusion vs. stenosis

# Historical Perspective
- Aortoilliac disease/Leriche's syndrome was first described by Dr. Robert Graham, a Scottish surgeon, in 1841.
- The symptoms of Aortoillliac disease described together as a syndrome was first discovered by Dr. Rene Leriche a French physician in 1940.
- In 1940, Dr. Leriche performed the first surgery to treat Aortoilliac disease/ Leriche syndrome.

# Classification
- Aortoilliac disease may be classified according to Trans-Atlantic Intercontinental Consensus guidelines  into 4 subtypes/groups:
- TASC Type A iliac lesions
Single stenosis less than 3 cm of the CIA or EIA (unilateral/bilateral)
- Single stenosis less than 3 cm of the CIA or EIA (unilateral/bilateral)
- TASC Type B iliac lesions
Single stenosis 3 to 10 cm in length, not extending into the CFA
Total of 2 stenosis less than 5 cm long in the CIA and/or EIA and not extending into the CFA
Unilateral CIA occlusion
- Single stenosis 3 to 10 cm in length, not extending into the CFA
- Total of 2 stenosis less than 5 cm long in the CIA and/or EIA and not extending into the CFA
- Unilateral CIA occlusion
- TASC Type C iliac lesions
Bilateral 5 to 10 cm long stenosis of the CIA and/or EIA, note extending into the CFA
Unilateral EIA occlusion not extending into the CFA
Unilateral EIA stenosis extending into the CFA
Bilateral CIA occlusion
- Bilateral 5 to 10 cm long stenosis of the CIA and/or EIA, note extending into the CFA
- Unilateral EIA occlusion not extending into the CFA
- Unilateral EIA stenosis extending into the CFA
- Bilateral CIA occlusion
- TASC Type D iliac lesions
Diffuse, multiple unilateral stenosis involving the CIA, EIA and CFA (usually more than 10 cm long)
Unilateral occlusion involving both the CIA and EIA
Bilateral EIA occlusions
Diffuse disease involving the aorta and both iliac arteries
Iliac stenosis in a patient with an abdominal aortic anuerysm or other lesion requiring aortic or iliac surgery
- Diffuse, multiple unilateral stenosis involving the CIA, EIA and CFA (usually more than 10 cm long)
- Unilateral occlusion involving both the CIA and EIA
- Bilateral EIA occlusions
- Diffuse disease involving the aorta and both iliac arteries
- Iliac stenosis in a patient with an abdominal aortic anuerysm or other lesion requiring aortic or iliac surgery

# Pathophysiology
- The pathogenesis of aortoilliac disease is characterized by atherosclerotic plaque buildup, Thrombosis or an embolus.
Atherosclerosis is the buildup of cholesterol plaques in the arteries. Damage to the endothelial layer of the vessel wall allows for inflammatory cells, mediators and fatty acids to enter the intimal layer of the artery. Overtime the plaques can enlarge and cause stenosis of the vessel lumen. Thrombosis occurs when a piece of the plaque dislodges and causes an occlusion.
- Atherosclerosis is the buildup of cholesterol plaques in the arteries. Damage to the endothelial layer of the vessel wall allows for inflammatory cells, mediators and fatty acids to enter the intimal layer of the artery. Overtime the plaques can enlarge and cause stenosis of the vessel lumen. Thrombosis occurs when a piece of the plaque dislodges and causes an occlusion.
- On gross pathology, cholesterol plaques, fatty streaks, and areas of ulceration and hemorrhage are characteristic findings of atherosclerosis and thrombus  formation in aortoilliac disease.
- On microscopic histopathological analysis, foam cells, necrotic core, fibrous cap and inflammatory infiltrate are characteristic findings of atherosclerosis and thrombus formation in aortoilliac disease.

# Clinical Features
Clinical features of aortoilliac disease include:
- Claudication of legs and buttocks
- Pallor of lower limbs
- Numbness of lower limbs
- Weakness and soreness of lower limbs
- Loss of femoral pulses
- Erectile dysfunction 
- Atrophy of affected muscles in the lower limb

# Differentiating Aortoilliac Disease from other Diseases
- Aortoilliac disease must be differentiated from other diseases that cause lower limb claudication, lower limb weakness/atrophy, and loss of femoral pulses such as:
- Peripheral artery disease of the Lower limbs 
- Compartment syndrome 
- Chronic venous insufficiency

# Epidemiology and Demographics
- The prevalence of peripheral arterial disease is approximately 200 million individuals worldwide.

## Age
- Aortoilliac disease is more commonly observed among patients aged 30-60 years old.
- Aortoilliac disease is more commonly observed among middle aged and elderly patients.

## Gender
- Males are more commonly affected with aortoilliac disease than Females.

## Race
- There is no racial predilection for aortoilliac disease.

# Risk Factors
- Common risk factors in the development of aortoilliac disease are smoking, diabetes mellitus, dyslipidemia, and hypertension.

# Natural History, Complications and Prognosis
- Early clinical features include intermittent claudication, decreased lower limb pulses, and erectile dysfunction.
- If left untreated, patients with aortoilliac disease may progress to develop critical limb ischemia, muscle atrophy, and poor wound healing.
- Prognosis is generally good, and the 5 year mortality rate of patients with peripheral arterial disease as a whole is approximately 33.2%. 

# Diagnosis

## Diagnostic Criteria
- The diagnosis of aortoilliac disease is made when 3 of the following diagnostic criteria are met:
- claudication
- weak lower limb pulses
- erectile dysfunction

## Symptoms
- Peripheral arterial disease may start out asymptomatic. Symptoms depend on the arteries affected.
- Symptoms of aortoilliac disease may include the following:
- claudication of lower limbs
- erectile dysfunction
- cold extremities
- weight loss
- pain in buttocks

## Physical Examination
- Patients with aortoilliac disease can appear normal or distressed in appearance.
- Physical examination may be remarkable for:
- weak lower limb pulses
- atrophy of lower limb
- cold peripheries
- pallor
- cyanosis

## Laboratory Findings
- Laboratory findings consistent with the diagnosis of Peripheral artery disease including aortoilliac disease include abnormal lipid panel  and abnormal inflammatory markers.
Elevated cholesterol
Elevated LDL
Elevated ESR
Elevated CRP 
Elevated homocysteine  
- Elevated cholesterol
- Elevated LDL
- Elevated ESR
- Elevated CRP 
- Elevated homocysteine  

## Imaging Findings
- CT angiography is the imaging modality of choice for aortoilliac disease.
- On CT angiography, aortoilliac disease is characterized by occlusion of the Common Illiac, External Illiac, or Common Femoral Arteries. 
- Doppler Ultrasound may demonstrate decreases blood flow in the Common Illiac, External Illiac, or Common Femoral Arteries.  
- Abdominal ultrasound may also be used to aid in diagnosis. 

## Other Diagnostic Studies
- Peripheral Arterial disease including aortoilliac disease may also be diagnosed using Ankle Brachial Index. 
- Ankle Brachial Index < 0.9 is suggestive of Peripheral Arterial Disease. 

# Treatment

## Medical Therapy
- The mainstay of therapy for Aortoilliac disease  is surgical. 
- Cilastazol a phosphodiesterase inhibitor can be used for symptomatic relief of Peripheral Arterial Disease.

## Surgery
- Surgical revascularization is the mainstay of therapy for aortoilliac disease.
- Open repair:
Aortofemoral bypass with or without endarterectomy can be used in the treatment of aortoilliac disease. 
- Aortofemoral bypass with or without endarterectomy can be used in the treatment of aortoilliac disease. 
- Endovascular Surgery:
Stent placement is another treatment option for aortoilliac disease.  
- Stent placement is another treatment option for aortoilliac disease.  

## Prevention
- Effective measures for the primary prevention of Peripheral arterial disease including aortoilliac disease include: 
Smoking cessation
Control of hyperlipidemia, Hypertension, Diabetes Mellitus
Low fat diet
Increase exercise
- Smoking cessation
- Control of hyperlipidemia, Hypertension, Diabetes Mellitus
- Low fat diet
- Increase exercise