An Investigation of Characteristics of Blood Flow at a Bifurcation with Reference to "Steal"

Abstract

Many factors affect the relative division of blood at a bifurcation. Clinically significant conditions sometimes result in a flow reduction to one downstream branch of a major bifurcation as the result of a reduction in the flow resistance of the contralateral branch. This condition is called “steal” and has been demonstrated at several major bifurcations in man. This behavior has been successfully modeled using the parameters of flow, pressure, and resistance in the upstream and two downstream vessels. The model was confirmed experimentally in mongrel dogs by a pressure versus flow study at the external iliac trifurcation. Flows were measured electromagnetically, and pressures by a fluid-filled catheter and diaphram LVDT transducer. Resistances were manually controlled. As a result of this study a simple test was devised to determine if a site selected for vascular surgery has a potential for developing steal.