Role of local hemodynamic abnormalities at pathologic tortuosity of the carotid arteries in development of vascular cerebral insufficiency

Abstract

Turbulence in blood flow in patients with pathological tortuosity of the internal carotid artery at a rate in excess of 1 m/s (Re > 1140), the occurrence of wall surface vortices and increase of blood flow rate by reducing the hydraulic diameter of the arteries result in the increased hemodynamic resistance of the vasculature and the brain hypoperfusion. Variety of forms and the complexity of the geometric configuration of arteries in their pathological tortuosity require an individual approach in determining the indications for surgical treatment and the choice of method of operation. The paper describes the objective biomechanical criteria based on instrumental clinical studies of hemodynamic disturbances and determining the pressure gradient in the areas of changing the geometry of blood vessels. The integrated use of anatomic and hemodynamic parameters allows us to estimate the energy losses and pressure gradients in pathological tortuosity of the internal carotid arteries in any geometric configuration. The extension of the proximal portion of the artery with respect to the pathological curvature was found which caused by the fact that the diameter of the mouth of the carotid artery with unilateral pathological tortuosity exceeds diameter of the mouth on the contralateral side. It was showed the occurrence of parietal swirl flow corresponds to a rate of 1.2 m/s and the total turbulence – at a speed of 1.4 m/s in the arteries with diameter of 4 mm. Flow rate at which a swirl flow is 0.8 m/s and a turbulent blood flow is recorded at a rate of 1 m/s by increasing the diameter of the carotid artery to 6 mm.