Aortoiliac occlusive disease – asymptomatic Leriche syndrome

An active 55-year-old male patient with a history of alcoholism, an active smoker, arterial hypertension and poorly controlled heart failure, with no previous complaints was brought to the ER in cardiac arrest. After reversal the patient was admitted to the Intensive Care.
A contrast-enhanced CT was performed for slight jaundice and increasing hepatic enzymes.

On CT no significant changes were present in the liver other than a slight hepatomegaly (Fig 1).
Incidentally the CT showed a complete occlusion of the abdominal aorta distal to the origin of the right renal artery (Fig 2, 3, 4, 5 and 6) without opacification of the left renal artery.
The aorta and its branches had severely calcified atheromatous plaques (Fig 2, 4, 5 and 6).
The left kidney was of smaller size and had delayed enhancement, while the right kidney had heterogeneous enhancement with hypodense peripheral triangular areas, favouring small renal infarcts (Fig 1 and 3).
Moderate splenomegaly with heterogeneous enhancement, which, given the clinical context, probably related to splenic infarcts was also present.
Superficial vessels (internal thoracic and inferior epigastric arteries) were dilated, in relation to collateral systemic-systemic circulation (Fig 4 and 6).

Aortoiliac occlusive disease (AOD) refers to the thrombotic occlusion of the abdominal aorta and/or iliac arteries [1, 2] and is a subtype of peripheral arterial disease [1, 2].
The main cause of AOD is atherosclerosis, but acute thrombosis, vasculitis or other causes may also be implicated [3].
AOD is associated with increased cardiovascular risk [2, 4, 5], as seen in our patient (smoker and history of medicated hypertension).
When symptomatic AOD is known as Leriche syndrome [1, 4, 6] and is classically associated with bilateral claudication with ischaemic pain, erectile dysfunction and absent or decreased femoral pulses. The exact symptoms are related to the aortic segments involved [1] and atypical symptoms may be seen. Nonetheless many patients remain asymptomatic due to the presence of networks of collateral vessels, which delay the onset of symptoms [1, 2, 3, 4].
Our patient had a collateral pathway through the internal thoracic artery to the inferior epigastric artery (Fig 4 and 6), also known as Winslow pathway [3], bypassing the obstruction.
CT angiography studies allow the diagnosis, even in asymptomatic patients [1, 2, 3, 4], making this the modality of choice for its non-invasiveness and capability to determine the extent of arterial occlusion as well as the presence and distribution of collateral vessels [2].
Magnetic resonance angiography may also be useful in the diagnostic workup, mostly in patients with chronic renal insufficiency [1, 2].
The knowledge of this entity in asymptomatic patients relates to importance of the network of collateral vessels which may be damaged in an unrelated surgical intervention [1, 2, 3], especially superficial collaterals, potentially leading to acute limb ischaemia.
The standard treatment is surgical aortobifemoral bypass or aortoiliac endarterectomy [5, 6] as well as endovascular approaches [1, 6], depending on the extent of involvement, but in asymptomatic cases these treatments are questionable and risk factor management alone may be preferred [4, 5].
In our case, the patient was transferred to vascular surgery department, but, as this was not an acute setting and the patient was asymptomatic with adequate collateral circulation, no intervention was performed and the patient was anticoagulated and scheduled for follow-up.
The imaging team is key in the detection of asymptomatic cases of aortoiliac occlusive disease. These cases are important essentially for planning surgical interventions, even if unrelated, as these could injure the collateral network in place and lead to acute limb ischaemia.