Geometrical changes of stent graft configurations after complex endovascular surgery

An abdominal aortic aneurysm (AAA) is defined as a dilation of the abdominal aorta > 1.5 times the diameter of the non-dilated infrarenal aorta. Complex abdominal aortic aneurysm is defined as an aneurysm that involves the infrarenal abdominal aortic segment which extends up to, and sometimes includes, the renal artery origins. Complex AAAs account for approximately 15% of all AAAs. Surgery of AAA can be performed by open surgical repair (OSR) or endovascular aneurysm repair (EVAR). Several techniques, such as chimney-EVAR (ChEVAR), chimney-EVAS (ChEVAS) or fenestrated-EVAR (FEVAR) are used in the treatment of complex AAA. Still, not all potential causes of failure, especially during long term follow-up, for ChEVAR, ChEVAS and FEVAR are known, which complicates selecting the best treatment strategy for a specific patient. Identification, visualization and prediction of complications associated with these complex techniques have not yet been elaborated on a large scale so far. The overall focus of this thesis is recognition and detection of specific geometric changes of the anatomy and device configurations for ChEVAR, ChEVAS and FEVAR in the treatment of complex AAA in order to understand causes of failure. New software-based methodologies have been developed to identify gutters, component instability and geometrical changes of stent graft configurations. This thesis shows that changes in geometry after endovascular treatment of complex AAA are often subtle but may still lead to complications, based on in-vitro and in-vivo research. Understanding mechanisms behind potential modes of failure help identifying the best treatment strategy for a specific patient, but also the proper follow-up regime.