Characterization of catheter dynamics during percutaneous transluminal catheter procedures

Remote catheter navigation systems are being developed to reduce the occupational risk of the intervening physician. Despite the success of such systems, development has occurred with little fundamental knowledge of the catheter dynamics applied by the interventionalist. This paper characterizes the kinematics of a catheter during manipulation, the minimum applied force/torque during interventional procedures, and the maximum force/torque applied by an operator to overcome vasculature friction. Ten operators manipulated a 6F catheter inside a specialized catheter movement sensor to determine the velocities and accelerations of catheter motion. A mass-spring apparatus was constructed to measure the forces and torques required to overcome introducer sheath and vasculature friction. Results showed the catheter was manipulated at peak velocities and accelerations of (mu +/- sigma): 360 +/-180 mm x s(-1) and 22200 +/-14000 mm x s(- 2), and 19 +/-7 rad x s(- 1) and 900 +/-510 rad x s(- 2), for axial and radial directions of motion, respectively. A minimum force of 0.29 +/- 0.06 N and a torque of 1.15 +/-0.3 mN x m was required to move the catheter through the introducer sheath; while the observed maximum applied torque was 15 mN x m to overcome vasculature friction. The implications of these results for future design optimization of an intuitive remote catheter navigation system are considered.