Leriche syndrome involves atherosclerotic obstruction of the infrarenal aorta.
Collateral pathways that may supply arterial blood to the lower extremities:
(1) Winslow's pathway (subclavian artery to the internal thoracic artery to the epigastric arteries, finally reaching the external iliac artery)
(2) lumbar system (lumbar arteries supplying the circumflex iliac and common femoral artery)
(3) mesenteric system (via Riolano's circles and the superior and inferior hemorrhoidal arteries to the internal iliac artery)
(4) iliac-femoral system (from the internal iliac artery to the deep femoral artery)
(5) anomalous artery from the a renal artery to the homolateral external iliac artery
In the steal phenomenon the flow of blood going to the lower extremity results in hypoperfusion within the distribution of the collateral arteries, which may result in:
(1) renal hypoperfusion
(2) intestinal hypoperfusion
If a patient with a steal phenomenon becomes symptomatic then the diagnosis of a steal syndrome can be made.
