The influence of experimental arteriovenous fistula on the development of the collateral circulation and on the devascularized limb.

The complicated features of congenital arteriovenous fistulas have emphasized the necessity for further study of collateral circulation to be developed around the fistulas. Influence of an arteriovenous fistula on the collateral circulation and on the distal circulation in the involved extremity was investigated by means of angiography, electromagnetic flow meter, and venous occlusive plethysmography, in dogs with an experimental arteriovenous fistula created by side-to-side anastomosis between the femoral artery and vein. The results showed that the collateral development is rapid, requiring only one week to be significant. The distal circulatio,n is reduced early in the postoper ative period but later tends to be restored rapidly and sufficiently to 80%' of the normal value concurrently with development of collateral arteries. When an arteriovenous fistula is constructed just distal to the femoral arterial occlusion, the development of collateral arteries is more rapid and effective for the distal circulation than in the limb with arterial occulsion only. The dilated arteries of collateral pathways r emain effective after closure of the fistula. The beneficial and detrimental effects of arteriovenous fistulas on the devascuJarized limb were discussed.