A Multi-DOF Tendon-Actuated Steerable Sheath for Precise Positioning in Percutaneous Left Atrial Appendage Closure

According to the 2020 Guidelines of the European Soci- ety of Cardiology, Atrial Fibrillation (AF) is recognized as the most prevalent cardiac arrhythmia, impacting approximately 2% to 4% of adults [1]. AF reduces left atrium contractility, increasing stroke risk fivefold. The percentage of strokes attributed to AF ranges from 1.5% at ages 50-59 to 23.5% at ages 80-89 [2]. Over 90% of left atrial thrombi associated with stroke originate from the Left Atrial Appendage (LAA). In recent decades, catheter-based procedures for mechanical Left Atrial Appendage Closure (LAAC) have emerged as a valid al- ternative to traditional long-term anticoagulation therapy for stroke prevention in AF patients. In the procedure, an occluder device is carried by a delivery sheath from the femoral vein to the left atrium, and it is implanted in the LAA. However, traditional LAAC procedures face sig- nificant challenges, including suboptimal device delivery and post-implantation peri-device leaks [3]. Commercial sheaths are passive and feature a pre-curved tip, thus limiting their adaptability to various LAA locations. We are proposing an innovative steerable sheath for LAAC which integrates a multi-Degree of Freedom (DOF) tendon-driven Nitinol tip actuated by a motor- ized system. The tip design provides tailored stiffness, independent proximal and distal segment bending, and fine control thanks to Nitinol’s superelasticity. These features aim to enhance co-axial alignment of the closure device with the LAA, facilitating a precise and effective implantation.