Coarctation of aorta (CoAo) accounts for 8 % of congenital cardiac disease. Balloon angioplasty is currently the preferred method for treatment of CoAo. However, given the viscoelastic properties of the aortic wall, sometimes the procedure has to be repeated until a satisfactory diameter is obtained, the diameter of the aorta decreases afterwards, and the final diameter can not be accurately estimated before the procedure. The objective of this study is to implement a mathematical model of angioplastic treatment of CoAo which can be used to predict the final diameter of the aorta, and to optimize the controllable variables of the procedure, such as balloon diameter, pressure and dilatation time. The combination of a perfect plastic solid and an ideal viscous material allows to obtain different models of a viscous-plastic material. Using the Bingham model, a general viscous-elastic-plastic model can be built. The viscoelastic properties of the aortic wall were obtained through tensile stress tests. Angioplastic treatment was modeled by three regions (see Figure) which define the stress-strain conditions of the problem: the first region (balloon inflation) consists of a rapid and linear increase of stress and deformation; the second region represents the time during the balloon remains inflated (constant stress); and the third region represents the change in the deformation and stress after the balloon is removed (relaxation). The differential equation of the viscous-elastic-plastic model was solved for each region, using as initial conditions the final conditions of the previous region.FigureThe expression for the diameter of the aorta after the procedure (region 3) is given by: The model is being currently adjusted and validated in clinical cases.