Computational modeling of vascular tissue damage for the development of safe interventional devices.

During intravascular procedures, medical devices interact mechanically with vascular tissue. The device design faces a trade-off: although a high bending stiffness improves its maneuvrability and deliverability, it may also trigger excessive supra-physiological loading that may result in tissue damage. In particular, the collagen fibers in vascular walls are load-bearing but may rupture on a microscopic scale due to mechanical interaction. When the mechanical load increases even further, tissue rupture or puncture occurs. To mitigate tissue damage, the current work focusses on the development of computational Finite Element (FE) based models wherein state-of-the-art constitutive tissue models are applied toward the design of safe devices. Several experiments are presented for tissue characterization in which device-mimicking indenters are pressed onto a porcine tissue. In these experiments, the Mullins effect, which is related to tissue damage, is observed. Consequently, the mechanical behavior of tissue, including the evolution of damage-induced energy dissipation, is accurately described by adopting a hyperelastic model incorporating the damage approach by Weisbecker et al. (2012). From the experimentally validated computational model, a novel design criterion is established, which allows for safe device development. Furthermore, an energy density criterion for the onset of puncture is proposed. With these tools, several frequently used work-horse guidewires are numerically evaluated.