Cardiovascular interventions / Stents
General - The cardiovascular system is the major blood flow system in the body and secures the surviving of the organism by providing transport of oxygen and nutrients. Pathologic changes of single veins or arteries may require a specific treatment using vascular implants, such as stents. To optimise the treatment outcome, a detailed knowledge of the local conditions and the choice of the optimum device is necessary. The effort for a complete complex three-dimensional transient numerical flow simulation of the whole system including the interesting part, however, is extremely high.
Object is the detailed description of the flow conditions in a blood vessel of interest, for instance as time-dependent distributions of blood velocity and blood pressure. An intended intervention, like the placement of a stent, should possibly be analysed with its effects on blood flow and vessel wall prior to the intervention.
Method - Virtual, simulation methods allow a three-dimensional, patient-specific reconstruction of single blood vessels. For the classification of a specific vessel in the cardiovascular system, a one-dimensional compartmental system was developed in co-operation with the University of Sheffield, which calculates the flow conditions starting from the heart for the whole arterial tree. This one-dimensional model is coupled with a detailed three-dimensional CFD (Computational Fluid Dynamics)-model of an artery or a part of it. With the analysis of the mechanical process of the stent delivery and deployment as well as the blood-flow-related parameters, the intervention can be predicted in great detail.
As result of the simulation, the surgical intervention can be predicted with regard to its effects on blood flow and vessel wall. Special simulation tools allow the prognosis of chemical and biological effects of the stenting such as drug elusion by the stent or the processes of thrombus formation (see biocompatibility analysis) or restenosis.