The Regulation of the Limb Circulation in Lymph-Oedema (Development of an Arteriovenous Shunt Circulation in Experimental Lymph-Oedema of the Leg)

Abstract

The effect of lymph stasis on limb blood flow was studied in 38 dogs where lymph-oedema of one of the hindlimbs was induced by ligation of the lymphatics on the thigh and of the regional lymph-node. Haemodynamic examinations were conducted in 17 animals; total blood flow and the nutritive flow to the muscles and skin (⁸⁶Rb extraction) were determined in both hindlimbs. Microcirculation was studied in 16 dogs by means of the india ink-gelatin injection method, the benzidine reaction and by the polyvinylchloride injection technique. In all cases specimens were taken from muscle, skin and subcutaneous connective tissue of both hindlimbs for light microscopic analysis. The results presented indicate an increase in total blood flow without any change in the nutritive flow to the skin or muscle in the lymph-oedematous limb. Lymph stasis induced intimal swelling and plasma infiltration of the intima and media of small vessels (pre-capillaries and metarterioles) of skin, muscles and subcutaneous tissue, which led to a blocked transportation of proteins. Small vessels of the limb with lymph-oedema were spottily dilated, whereas at other areas compressed capillaries could be seen. Evidence is supplied for the appearance of arteriovenous shunt circulation in lymph-oedema of the lower limb. In a previous study we observed that, unlike venous congestion, lymph-oedema of the limbs in man was accompanied by increased blood flow and a conspicuously low arteriovenous oxygen difference in the limb. (1) This finding led us to assume that chronic lymph stasis may induce arteriovenous shunt circulation. The present experiments were designed to study relative changes of total and nutritive limb blood flow and to examine alterations of the microcirculation in experimental lymph-oedema of the limb.