The Superficial Femoral Artery (SFA) is the longest section in the femoropopliteal artery and can reach a length of 28~32 cm. Therefore, multiple narrowings (stenoses) can occur along its length. In these cases, and especially when the stenosis is narrow and long, two or three overlapping stents are inserted into the artery, one after the other. Stent overlapping is a significant risk factor of stents fracture and in stent restenosis, which can lead to intermittent claudication and limb ischemia and in some cases may result in amputation. The aim of this research was to formulate an approach for calculating the stresses that the stents exert on the artery and one stent on each other. This goal was implemented using analytical and numerical models. The analytical model was formulated for an artery with linear elastic mechanical properties. The numerical models were formulated, first, for the same mechanical properties (for comparing both models) and then for an artery with hyper-elastic mechanical properties. All models were formulated also for cases of single stent without overlapping. The results of all models showed significant difference between the radial stresses exerted on the artery walls. For overlapping stents, the radial stresses were greater at about 150% than the stresses in single stent. Moreover, the stresses which occur on the stent`s struts were greater by 1,750% for the overlapping stents than those in single stent. Generally, the analytical model enables to understand the effect of each parameter (geometry and material properties) on the exerted stresses on the artery wall and on the stent`s struts and can help in the design of optimal stents for cases with overlapping stents.
