Semi-automated evaluation of stentgrafts

Purpose: The short and long-term outcome of endovascular aortic aneurysm repair is influenced by selection of stentgraft design and, in particular, correct oversizing. To support the preoperative planning process and device selection results of a finite element analysis (radial forces, contact states) have to be interpreted in clinical environment. Methods: Data interpretation is assisted by defined risk classifications and a system-generated variant suggestion which is performed using weighted evaluation criteria (proximal/distal sealing and fixation). For better estimation of migration risk the calculated radial force multiplied with a friction coefficient, is compared with proximal and distal flow force values stated in the literature. Sealing potential is calculated based on defined contact elements of the simulation model. Results: The developed approach enables a semi-automated evaluation of stentgrafts and a quantitative comparison of different implant configurations. A graphical user interface highlights a variant proposal and their surplus referring fixation and sealing proportional to other variant results. For providing a good survey of risk assignments an illustration of landing zones with color coded variant identifiers is available. Conclusion: The presented method for quantitative evaluation of stentgrafts can assist the vascular surgeon in implant selection. Further investigations are necessary to determine qualitative "not-quantifiable" criteria and identify variables (e.g. underlying aortic pathology, etiology etc.) influencing semi-automated evaluation of stentgrafts.