In this paper a Petri net based model of the process of endothelial dysfunction is presented. The model describes
some selected aspects of this process and their relation with atherosclerosis. Models expressed in the language
of Petri net theory have, on the one hand, an intuitive graphical interpretation, and on the other hand, they can
be analyzed using rigorous mathematical methods. Such analysis and simulation of the net behavior can be supported
by many freely available software tools. Here, results of an analysis based on t-invariants of the proposed
model are presented. In particular, feasible t-invariants, MCT-sets and t-clusters have been calculated and their
biological meaning has been determined.