Active Stents

• Applicants: Professor Dr.-Ing. Giorgio Cattaneo; Professor Dr.-Ing. Maurits Ortmanns; Professor Dr.-Ing. Thomas Stieglitz
• Subject Area: Biomedical Systems Technology
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 505063610

Cardiovascular diseases and stroke represent the first and third cause of mortality in Germany. Both diseases are mostly caused by a narrowing or occlusion of a blood vessel. Catheter-based interventions allow for a minimally invasive treatment of cardio- and neurovascular pathologies. Self-expandable implants - generally defined as stents - have allowed for a reduction of catheter dimensions. However, implantation within small blood vessels can invoke serious hazards, including in-stent thrombosis, distal embolism, vessel restenosis or vessel injury. Moreover, patients with vascular pathologies often present comorbidities like high blood pressure or diabetes. Therefore, there is an enormous need for advanced vascular implants endowed with monitoring functions of tissue, fluid dynamics, biochemical or physical parameters, with the potential to improve implant reliability and to provide information on physiological variables. This project proposal aims to generate fundamental knowledge and methods for a long-term integration of active sensing electronics into high deformable, self-expandable vascular implants, thus realizing active stents. Three partners with distinct and complementary expertise in the fields of integrated circuits, stent design, encapsulation, integration and experimental anatomical models join in this project.University of Freiburg will develop methods to reliably integrate and interconnect multiple silicon based integrated circuits (chiplets) as well as coils into flexible substrates with organic and inorganic barrier layers to achieve longevity in humid environment. These systems will be later embedded in braided stents with adequate guiding and holding structures. Design and development of these flexible electronic systems allow compression and expansion within braided stents during delivery and application.University of Ulm will design stentennas to power and communicate with the active stents, as well as miniaturized integrated circuits, providing the power management, sensor interface and communication electronics to the active stent. As an initial experimental prototype, a PCB based platform is made available for testing in large scale stents. University of Stuttgart will develop stent scaffolds made of braided microwires as carriers for the electronics. Scaffolds will be designed to allow the integration of electronic components, at the same time providing mechanical performance for catheter delivery and self-expansion. Manufacturing of anatomical models will allow for investigation of mechanics, fluid- and hemodynamics and finally electrical function of the active stent under pulsatile flow conditions in mock circulatory loop. Together, the three partners work towards answering the fundamental question about how active electronics can be long-term immobilized, powered and wirelessly accessed within a stent without impact to the stent mechanics and fluid dynamics in a physiological environment.

• DFG Programme: Research Grants