The success of balloon angioplasty and stent implantation depends on a balance between two conflicting objectives: maximization of artery lumen patency and minimization of mechanical damage. A finite element model for the patient-specific prediction of balloon angioplasty and stent implantation is proposed as a potential tool to assist clinicians. This paper describes the general methodology and the algorithm that computes device/artery interaction during stent deployment. The potential of the model is demonstrated with examples that include artery model reconstruction, device deployment, and prediction of friction on the arterial wall.