Biological maintenance of distal vein arterialization.

Eleven weeks after surgery, a fine microvessel network was seen in the feet of patients with arteriosclerosis obliterans treated by distal vein arterialization. A possible mechanism for establishment of blood flow to, and biological maintenance of, the graft in the foot, in relation to oxygen consumption rate during walking was investigated, using Krogh's tissue cylinder model. Our calculations showed that the increase in oxygen consumption rate of the muscle when patients walked would reduce the size of the oxygen front in the tissue cylinder, thus producing small, transient hypoxic regions in skeletal foot muscle. Such muscle hypoxia, although localized, could stimulate synthesis of vascular endothelial growth factor and facilitate angiogenesis in the grafted tissue. The architecture of fine microvessel networks observed in the foot by angiography seems consistent with this supposition and, moreover, suggests that the reinstatement of blood vessel networks in the foot tissues after grafting is supported by "normal" biological mechanisms.