Wall Shear Stress Predicts Venous Tissue Growth in Endovascular Neural Interfaces.

Traditionally, venous stents have been employed to maintain vessel patency in cases of venous obstruction. Recent advancements in stent-electrode technology have broadened their application to include endovascular neural interfaces for neurotechnological purposes within cerebral veins. However, the effects of neointimal hyperplasia on large venous sinuses, particularly the superior sagittal sinus and jugular vein, remain poorly understood. Additionally, concerns such as thrombosis, chronic inflammation, and tissue overgrowth pose challenges for their long-term use as neural interfaces. To investigate the impact of venous stenting on blood flow and tissue growth, we utilized Computational Fluid Dynamics (CFD) modeling and animal experiments, assessing blood flow and tissue responses over 28 days. Our findings revealed a negative power law correlation, with low wall shear stress (WSS) identified as the primary driver of accelerated tissue growth. Unlike the focal narrowing typically observed in stented arteries, venous tissue growth exhibited greater variability. Additionally, the threshold for low WSS that triggered growth was smaller than previously reported in arteries. This study provides new insights into venous neointimal hyperplasia, emphasizing the need to consider venous-specific responses in stent-electrode design and clinical applications. Nonetheless, potential risks such as thrombosis and inflammatory responses should be further investigated to fully understand the long-term viability of these devices. Understanding the biomechanical environment of stents in cerebral veins can guide the development of next-generation neural interfaces and inform clinicians and device developers about potential impacts on long-term outcomes.