Clinical Physiology: The Effect of Induced Arterial Hypertension upon Regional Blood Flow in Subcutaneous Tissue in Patients with Arterial Insufficiency of the Legs

Abstract

In nine patients with arterial insufficiency of the legs, the effect of induced arterial hypertension upon blood flow in subcutaneous tissue was correlated to the changes of blood flow in subcutaneous tissue during dependency. Arterial pressure was increased by constant intravenous infusion of angiotensin. Blood flow in subcutaneous tissue was measured 10 cm distal to the head of fibula, at the lateral malleolus, and at the base of the first toe by means of the xenon washout technique. It was found that in areas where blood flow decreased during dependency, blood flow decreased during angiotensin infusion. An increase in blood flow during angiotensin infusion was seen in areas where blood flow increased during dependency. It is concluded that the effect of angiotensin infusion on blood flow and of therapeutically induced hypertension can be predicted from the effect of orthostatic changes on blood flow. The results obtained support the hypothesis that the vessels behave as passive channels (i.e. blood flow depends mainly upon arterial perfusion pressure) in areas where the normal vasoconstrictor response to increased transmural pressure is abolished.