We have constructed a diagnostic support system for circulatory disease based on a volume communications environment. This system is based on a VizGrid environment, i.e. an integrated environment consisting of a data archiving system, a collaboration system, and a computational grid system. In this system, we simulate blood flow in a patient's individual blood vessel geometry and blood vessel wall using a weak coupling method. This system can be used with three-dimensional images from CT/MRI, for medical treatment and for simulating blood flow in a blood vessel with circulatory disease in a volume communications environment. With this system, it becomes easy for researchers in remote locations to collaboratively discuss the relevant object, even for complex explanations like the simulation results.