Stent implanation is one of the clinical treatments of stenotic arteries. This clinical procedure requires careful planning that considers the geometry of the artery of the particular patient. The numerical simulation can be very useful to analyze the state of the arterial wall during and after this intervention. The numerical model considered within this paper simulates the expansion of the stent and subsequent deformation of the arterial wall using finite element method. This model was validated in literature against clinical data. Within the implementation, the tetrahedral finite elements were used. But, this type of elements can cause inaccuracies and instability during simulations. Within this paper, the stent implantation software was improved by implementing hexahedral finite element mesh and applying an additional remeshing technique in order to ensure better prediction of forces exerted on stent and stress within arterial wall. The benefits of these additions are demonstrated on the simulation of stent implantation with patient-specific coronary artery. This software can be used to analyze quickly the effect of different stent size and position on the state of the arterial wall after the intervention. It represents a valuable and reliable tool for the clinicians that can help them determine the outcome of the stenting intervention and thus improve the patient-specific pre-operative planning process.