Mathematical models of the cardiovascular system (CVS) allow to explore the inner workings of the human body and therefore provide various benefits to medical education. There are indeed some comprehensive models covering complex physiological mechanisms, yet, most of these do not provide the flexibility to change the defining parameters at all times. In this paper, we present CAVA – an interactive, hemodynamic model of a cross-scale CVS that provides just this flexibility, combining the trachea, lung, heart and vascular system approximated as a single vessel. We evaluated the outcome by comparison to empirical measures from literature and analyzed its performance, demonstrating that CAVA is well suited for real-time interactive systems. The code base including examples for two game engines is provided open-source.