Evaluation of carotid stent scaffolding through patient-specific finite element analysis

The relevance of stenting procedures in the treatment of carotid artery disease cannot be underestimated. Successful carotid stenting does not only depend on the operator skills, but also on proper choices among the different stent designs available in the market. Consequently, it is reasonable to suppose that an optimal stent design can be obtained as a trade-off of different features as scaffolding, flexibility, and vessel adaptability. In particular, scaffolding, defined as the amount of support given to the vessel wall by the stent, has a leading role in the minimization of the embolic risk. Vessel scaffolding is usually measured as the cell area of the stent in free-expanded configuration. This approach neglects the actual stent configuration within the vascular anatomy; accordingly, in the present study we propose a novel methodology to evaluate the vessel scaffolding applied to a given stent design deployed in a realistic carotid artery model through patient-specific finite element analysis. The results suggest that post-stenting cell area varies along the stent length as a function of the vessel tapering, confirming that the conclusions withdrawn from the free-expanded configuration should be carefully handled, since they do not take into account post-implant variations. Moreover, such variability seems to be more pronounced in open-cell designs, especially at the bifurcation segment. Our study confirms the capability of dedicated computer-based simulations to provide useful information about complex stent features, which are essential for novel stent designs or for pre-surgical planning.