Why can atherosclerosis in the legs lead to gangrene?

Atherosclerosis in the legs can lead to gangrene because it causes a critical reduction or total obstruction of blood flow to the extremities.123

The process begins with the buildup of fatty plaques—composed of cholesterol, lipids, and cellular debris—within the inner lining of the arteries. As these plaques enlarge, they narrow the arterial lumen, significantly restricting the delivery of oxygenated blood and essential nutrients to the tissues of the legs.23

When blood supply is gradually decreased, the affected tissue may develop dry gangrene, characterized by the tissue becoming cold, discolored, and eventually necrotic. If the blood flow is suddenly cut off, such as by a blood clot forming over a ruptured plaque, the tissue may suffer more acute damage, potentially leading to moist gangrene. In both scenarios, the lack of adequate blood supply results in the localized death of soft tissue, which is the defining characteristic of gangrene.123