In this paper we present a CFD analysis of blood flow within a guinea pig vessel to investigate mechanosignaling effects when endothelial cells are subjected to fluid shear stress conditions. Blood is considered to be incompressible and the flow model is described by the Navier-Stokes and the continuity equations. The rheological behavior of the blood is based on the Power law and the Casson constitutive equations. A standard Galerkin finite element technique has been applied for the solution of the flow equations within a 2-D axisymmetric and 3-D framework. Relationships of the stenosis severity and flow data such as flow rate and flow pressure are obtained from the numerical simulations. Results are presented in the form of simulated flow patterns and wall shear stress plots within the computational domain. The effects of disturbed flow patterns on the wall shear stress have been investigated downstream of the constriction to compare with endothelial mechanosignaling patterns found within guinea pig vessels. Finally, a comparison of the 2-D and 3-D simulations has been carried out to assess the accuracy of the simulations against available experimental data.