Surface microstructure design and validation of flexible interventional guidewires: A comprehensive comparative study

The intricate and narrow vascular networks present significant challenges for the compliance, flexibility, and maximum bending capabilities of interventional instruments. By focusing on the constrained bending capacity of guidewires in vascular procedures, the research delves into the surface microstructure design of flexible interventional guidewires to enhance their bending angles. This advancement facilitates smooth interventional procedures within limited workspaces. The research investigates how various structural size parameters of the surface microstructure affect the maximum bending capability of interventional guidewires. It encompasses the design and manufacture of four types of flexible interventional guidewires featuring rectangular, triangular, arc-shaped, and concave-pit-shaped microstructures. A theoretical model for guidewire bending angles is established, and through theoretical numerical analysis, the correlations between different microstructures, microstructural size parameters, and bending angles are elucidated. The study examines the bending characteristics of the four microstructured flexible interventional guidewires under tendon stretching displacement. Simulation analysis is employed to assess the influence of microstructural size parameters on the bending angles of the guidewires, confirming that guidewires with concave-pit-shaped microstructures can achieve greater bending angles, thereby enhancing their bending capabilities. An experimental setup is arranged to explore the bendable angles of the flexible interventional guidewires with the four types of microstructures. Furthermore, experiments on the interactive compliance between the microstructured flexible interventional guidewires and blood vessels are conducted to validate the guidewires’ deformation capabilities. The study affirms that the flexible interventional guidewire with concave-pit-shaped microstructures displays a greater bending angle. Specifically, the concave-pit-shaped microstructured flexible interventional guidewire, measuring 50 mm in length, can achieve a bending angle of 195° when subjected to a tendon stretching displacement of 4 mm, enabling successful interventions in intricate and narrow vascular networks like those encountered in heart/brain vasculature.