Design and Evaluation of a Magnetic Rotablation Catheter for Arterial Stenosis

Arterial stenosis is a high-risk disease accompanied by large amounts of calcified deposits and plaques that develop inside the vasculature. These deposits should be reduced to improve blood flow. However, current methods used to reduce stenosis require externally-controlled actuation systems resulting in limited workspace or patient risks. This results in an unexplored preference regarding the revascularization strategy for symptomatic artery stenosis. In this paper, we propose a novel internally-actuated solution: a magnetic spring-loaded rotablation catheter. The catheter is developed to achieve stenosis-debulking capabilities by actuating drill bits using two internal electromagnetic coils and a magnetic reciprocating spring-loaded shaft. The state-space model of the catheter is validated by comparing the simulation results of the magnetic fields of the internal coils with the experimental results of a fabricated prototype. Contact forces of the catheter tip are measured experimentally, resulting in a maximum axial force of 2.63 N and a torque of 5.69 mN-m. Finally, we present interventions in which the catheter is inserted to a vascular target site and demonstrate plaque-specific treatment using different detachable actuator bits. Calcified deposits are debulked and visualized via ultrasound imaging. The catheter can reduce a stenosis cross-sectional area by up to 35%, indicating the potential for the treatment of calcified lesions, which could prevent restenosis.