Análise do design de stents arteriais coronários baseado na hemodinâmica computacional

Abstract

Annually, thousands of people died from atherosclerosis, that is a disease caused by the hardening of the arteries which impair blood flow within them. One of the most used treatments is the application of stents, that are devices inserted in the interior of arteries with the aim to restore blood flow to its original condition. However, a recurrent problem in this type of surgical intervention is restenosis, a new deposition of fat layers in the region of stent which causes a new obstruction. To propose improvements in design and geometry for the stents commercially used, it is used fluid mechanics applied to blood flow: computational hemodynamics. For this, this present work makes use of the theory to analyze if the chance of the cylindrical geometry (commercially used) to conical could increase the lifespan of the stent inside the artery. For this, it is used boundary conditions which simulates blood pulsation (transient regime) proposed by Vimmr et al (2012) and three different types of models for blood: Newtonian, Carreau (most commons) and Power-Law. To analyze which stent is the most efficient (minimize the occurrence of restenosis) the WSS and OSI parameters were used based in the studies in the literature. The higher WSS value and the lower OSI value, the lower the chances of fat layer or cells being deposited in the places where stents are inserted. As main results, it was found that in all situations and for all the models of blood used, the conical model is the more efficient than the cylindrical one. For the models used for blood, Newtonian and Carreau had very similar results, while PoweLaw generated very different numbers and therefore it should be further analyzed for its applications in the analyzed cases. Thus, the conical model, for the conditions simulated, has a high potential to be tested in the future as a solution to mitigate restenosis.