A Steerable and Expandable Magnetic Aspiration Catheter for Enhanced Aspiration Thrombectomy

Abstract

Aspiration thrombectomy is widely used when treating acute ischemic stroke. A blood clot is directly suctioned through a catheter connected to a vacuum system. Although an increase in catheter bore size significantly enhances aspiration efficiency, this compromises endovascular navigability during manual manipulation. To minimize this trade-off, this paper presents a novel, magnetic aspiration catheter that enables both active steering and distal-end expansion via externally applied magnetic fields. The catheter incorporates dual-axis magnetization. Axial magnetization facilitates directional steering by aligning the catheter tip with the magnetic field; radial magnetization enables dynamic expansion of the cross-sectional area in response to the field strength, thereby improving clot contact and reducing leakage between the catheter and vessel wall. A magnetic mold-based fabrication method is employed to realize such dual-axis magnetization. The magnetically actuated motions of the catheter are theoretically and experimentally validated. Active steering reduces the navigation time by 67.5% (30.3 vs. 93.1 s) and expansion increases the aspiration force by 430% (27 vs. 143 & micro;N). Catheter efficacy and feasibility in terms of aspiration thrombectomy are demonstrated using 3D vascular phantoms. By enhancing both navigational control and therapeutic performance, this study advances the development of practical robotic systems for rapid and precise stroke treatment.