Collateral circulation in occlusion of lower limbs arteries: an anatomical study and statistical research in 35 old subjects.

The collateral circles formed following lower limbs arterial occlusion and their hemodynamic function have been described; 35 subjects (23 men and 12 women; age range 65 to 80), with symptomatic lower limbs obstructive arteriopathy (Fontaine's stage II) following occlusion of vessels downstream the subrenal aorta have been studied by means of Contrast Angiography and Color Doppler Echography of the vascular district including the terminal aorta and the lower limbs arteries. The hemodynamic significance of the collateral circles was assessed by calculating the Windsor index. In this population, the collateral circles for each level of obstruction were explored. Occlusion of the terminal abdominal aorta: the collateral circle was mainly established through the inferior mesenteric and ischiatic arteries and through the lumbar, ilio-lumbar and gluteal arteries; occlusion of the iliac tract: the collateral circulation was established through the spermatic or ovaric artery and through the funicular, external pudendal and middle sacral arteries; occlusion of the ilio-femoral tract: the collateral circulation was formed by the internal and external pudendal arteries and by the ilio-lumbar, obturating, gluteal and circumflex iliac arteries; occlusion of first tract of the superficial femoral artery: collateral circulation was established through the deep femoral artery and through the perforating arteries; occlusion of the terminal tract of the superficial femoral artery: collateral circulation was formed by the articular branches of the same artery originating proximal to the occlusion and through branches of the deep femoral artery; occlusion of the superficial and deep femoral arteries at their origin: collateral circulation was established through the ischiatic artery (directly and, indirectly, through the perforating arteries), and through the tegumental arteries. The hemodynamic significance, as measured by Windsor index was higher the more proximal was the occlusion, in accord with the lower caliber and/or number of vessels involved in the collateral circles.