Vascular disease and vascular function in the lower limb in diabetes.

This review examines the pathology, clinical effects and physiological disturbances produced by vascular disease and autonomic neuropathy in the lower limb in diabetic subjects. Atherosclerosis is a major factor in causing foot lesions in diabetics. The distribution of the disease frequently makes vascular reconstructive surgery difficult or impossible but an aggressive approach to reconstruction is justified because the results of major amputations are bad. Arterial calcification probably has no significant effect on the blood supply to the foot. There is some evidence that disease of arteries in the foot may be associated with the development of ulcers or gangrene. Disease of the arterioles and capillaries is frequent, but there is little evidence that this microangiopathy causes lesions. Autonomic neuropathy affecting the limb is also common, and although there are several mechanisms by which this might predispose to ulcers or gangrene, there is little evidence of such a direct relationship. In a patient presenting with ulceration or gangrene of the foot it is often impossible to determine the relative roles of vascular disease, affecting large or small vessels, and neuropathy, either somatic or autonomic, in the development of the lesion. Further progress depends on the development of more direct methods for assessing microvascular and autonomic nervous function.