Article is dedicated to describe new extended method of arterial hypertension most effective therapy and therapies combination detection method, which includes mathematical processing techniques. At the introduction part of the article authors discuss medical expert systems which by working field comply with developed method and decision making system. Main goal of this medicine system survey is to establish structure of medicine expert system which is in development phase. Also a possibility of knowledge representation and decision support process methodology is described to select the most appropriate solution. Then possible structure of system is described, after that extension of topological model is considered. Extension includes enhancement of existing model and attachment of a new pathogenesis in one common model. In this case model processing becomes much complicated, because node count and therapies combination count increases. To solve this issue authors present mathematical calculation techniques to reduce graph computation and decision support process complication. Calculation of graph processing usefulness and quantitative comparison is performed. At the ending part authors propose further system applications and possible mathematical processing tools.