Insight into the significance of blood flow inside stenosis coronary jointed with bypass vein: The case of anemic, normal, and hypertensive individuals

Background and objective: Recently, transplant of bypass vein is employed to charge blood fluid inside vein after stenosis position. Because, bypass vein can compensate consequences of stenosis in reducing blood flow within vessels. Therefore, analyses of shear stress for anemia, normal, and hypertensive individuals can prepare a valuable understanding in mechanical geometry which is applicable to design of transplantation especially for critical condition of shear stress. In this work, the transplantation of vessels is simulated in Fluent software, and user-defined function is used to indicate the blood properties as a non-Newtonian fluid based on Carreau fluid model.

Methods: Generally, shear stress profiles are studied for three cases of anemia, normal, and hypertensive individuals. Also, stenosis with the severity of 30% is simulated before the junction of host and grafted vessels. Finally, the results of shear stress on the walls (WSS) are reported with respect to three divided sections. Section one related to the distance from the stenosis position to the joining position of veins. Section two is the complete distance of the transplantation of veins, which blood flows are mixed. Section three is related to the distance after transplantation of host and grafted vessels.

Results: It was reported that flow separation causes the velocity of blood flow increases, which enhances shear stress. Moreover, increasing velocity in a hypertensive individual can exacerbate the shear stress. Maximum shear stress is as much as 105 Pa, 125 Pa, and 220 Pa in order of anemia, normal, and hypertensive individuals with abbreviations of LHD, NHD, and HHD, orderly.

Conclusions: A comparison of maximum shear stress values in the Heel and Toe section showed that transplantation of veins can be a critical position of failure, which is introduced potentially as a sensible position for medical treatment and related surgeries.