NUMERICAL INVESTIGATION OF BIOMECHANICAL INJURE OF CURVED VESSELS INDUCED BY INTERVENED BALLOON EXPANDABLE VASCULAR STENT

The schematic nonlinear finite element model of intervened vascular stent is developed to investigate the relationship between stent design, arterial geometry and injures induced by implantation of a balloon expandable vascular stent into a stenosed artery. The influence of plaque composition in its constitutive model is also considered. The arterial wall stress distribution and magnitude are obtained and analyzed during A-stent and B-stent intervened to a curved vessel with varying restenosis rate of -24%, 40% and 50%, and curvature radius of -6 mm, 10 mm and 20 mm. The numerical results show that the arterial wall stress remarkably increases with increasing restenosis rate, while it decreases slowly with increasing curvature radius of the curved vessel. However, the arterial wall stress is much higher during expanding the stent than that during unloading the stent. Consequently, the resulting high arterial wall stress during expanding the stent can lead to plaque or arterial rupture and subject them to biomechanical injure. In addition, the stresses induced within plaque tissues and arteries by A-stent implantation is less than those by B-stent implantation because the former equipped with more flexible links exhibits larger longitudinal flexibility than the latter. These findings suggest a lower risk of arterial biomechanical injury for A-stent as compared with B-stent.