Design optimization for Nitinol thin film based flow diverter stents for the treatment of intracranial aneurysms

Friday, May 17, 2019: 9:30 AM
K2 (Bodenseeforum Konstanz)
Mr. Prasanth Velvaluri , University of Kiel, Kiel, Germany
Mrs. Mariya Pravdivtseva , Kiel University Hospital, Kiel, Germany
Dr. Rodrigo Lima de Miranda , Acquandas GmbH, Kiel, Germany
Prof. Olav Jansen , Kiel University Hospital, Kiel, Germany
Prof. Eckhard Quandt , University of Kiel, Kiel, Germany
Intracranial aneurysms (IA’s) are localized dilations of the cerebral blood vessels. There are two treatment strategies for this disease: Surgical which includes clipping or endovascular including coiling, stent assisted coiling and flow diversion with stents (FDS) or intraneurysmal devices.

Current FDS functions by steering the blood flow away from the aneurysm and promotes endothelialisation at the neck of the aneurysm, they are the most used therapies to treat IA’s. Commercial FDS have limitations regarding: miniaturization, addition of extra functionality, and increasing the fatigue safety because of their manufacturing routines.

Nitinol (NiTi) thin film technology, which is a combination of several processes of the micro-system technology, addresses the limitation with high degree of design freedom, miniaturization and improved fatigue resistance.

In order to develop the next generation of thin film flow diverter stents, criteria such as stress evolution during crimping and radial forces on vessel wall after stent deployment are factors that must be taken into consideration. The evaluation and optimization of the design is done by finite element method (FEM) modelling.

In the present study, we have used Abaqus for understanding the crimpability of the stent by considering a nonlinear material model. Furthermore, the produced stent with optimal design was deployed into 3D printed patient specific aneurysm models and has been evaluated for flow diversion efficacy using 4D flow MRI (3T, Philips). We would also present the 3D material validation for FEM along with a routine to investigate the design influence on the stent crimpability and its flow diversion properties.

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