Shows how numerical solutions of the human cardiovascular system may be devised by coupling models having different physical dimensions. One of the aspects of the circulatory system is its multiscale nature. Local flow features may have a global effect on circulation. For instance, a stenosis caused by an atherosclerotic plaque may change the overall characteristic of the vessels involved, and consequently have significant influence on the flow in the whole system. Hence, it would be useful to set up a numerical device that could represent accurately both local and systemic features. For this, it is necessary to couple together different model scales, from lumped models (which are traditionally described by means of an electrical network analogue) to local models based on 2D or 3D Navier-Stokes equations, passing through intermediate 1D models. In this paper, the different assumptions underlying these models, some mathematical issues related to their coupling and preliminary numerical results are presented