Transport phenomena in pulsating post-stenotic vortex flow in arteries. An interactive concept of fluid-dynamic, haemorheological and biochemical processes in white thrombus formation.

Blood in its native state is a highly "non-Newtonian" or anomalous fluid; this notwithstanding, in its native state, all cellular and plasmatic components remain in isolation and do not interact with each other or with the endothelial cells. The rheological behaviour of flowing blood, and that of blood components during the formation of thrombi, coagulate and thrombotic deposits, can be using a three-step procedure. The present paper deals with these, by delineating: the flow conditions under which flow occurs in various vessels, in stenoses, bifurcations under the influence of variable haemodynamic and geometric conditions; the so-called "flow properties" of blood components such as apparent viscosity, behaviour in shear, their behaviour in non-laminar flow, i.e. that occurring near and at sites of secondary flow. As a subsequent step, it is necessary to design appropriate test devices to assay the rheological behaviour in vitro of blood components under closely controlled fluid-dynamic, physico-chemical and biochemical conditions. The present review outlines the characteristic details of microflow in secondary flow (short-lived vortices) such as they prevail in pulsatile flow in arterial segments with "non-cylindrical configuration". In honour of the late Alexander Naumann, one of the founders of contemporary biofluid dynamics in Germany, the characteristic and functionally inseparable fluid-mechanical and rheological peculiarities of flow in eddies or vortices are termed Alexander Naumann vortex flow. They consist of a combination of high shear, recirculation and stagnation point flow. The micro-rheological, cytological and biochemical behaviour of blood platelets in such vortices is described, the integral effects of which render to the vortex the characteristics of a short-lived flow reactor for rapid pro-coagulatory processes and deposition of activated blood components onto the vessel wall.