Crossing Total Occlusions using a hydraulic pressure wave: a feasibility study

Abstract

Crossing highly calcified occlusions is technically challenging mainly due to guidewire buckling. In an effort to prevent buckling, a catheter that uses a dynamic impulse load is proposed. The proposed Wave catheter consists of an input plunger to generate an impulse at the handle, a hydraulic pressure wave confined within a Ø2 mm catheter to transfer the impulse towards the tip, and an output plunger to transfer the impulse to the occlusion. To determine the feasibility of this catheter, an experiment was performed in which the input and output impulses were recorded as a function of the catheter type, curvature, and plunger travel distance. Additionally, the system was tested on artificial CTO models to determine the clinical validity. The catheter has illustrated the ability to safely transfer high-force impulses of up to 43N (1.5 N required) with only minimum catheter type and no curvature dependency, allowing for delivering high-force impulses through tortuous vasculature and under any angle. Furthermore, the catheter was able to penetrate the artificial CTO models within 1 strike.

Crossing Total Occlusions Using a Hydraulic Pressure Wave: Development of the Wave Catheter

“…There was, however, a discrepancy between the COMSOL modeling results and the actual catheter result with respect to the effect of curvature. In the COMSOL model, as well as our previous study (21), it was found that the curvature of the shaft does not have a significant effect on the efficiency of the system. In our experimental results with the developed catheter, we found that the curvature did have a significant effect.…”

“…The theoretical maximum frequency the Wave catheter can function is equal to the velocity of the pressure wave. In a previous study (21), we found that the fluid travels with an approximated velocity of 550-585 m/s through the catheter. This velocity translates into a maximum frequency of 550 Hz and thus an assumed crossing time of 0.14 s.…”

“…Based on the results of the COMSOL model and previous experiments (21), it can be concluded that the stiffness of the shaft is of significant influence on the efficiency. The catheter shaft should be able to resist radial and axial expansion caused by the pressure wave surge, while still allowing for bending motion.…”

“…It was observed that a higher input impulse and a more flexible catheter design negatively influenced the efficiency, whereas catheter curvature did not have a significant effect. Furthermore, we were able to transfer a high-force impulse of 40.5 N without buckling (21). The ability to transfer high-force impulses through a highly tortuous shaft and under angle, allows for effective treatment of CTOs at any location inside the human body, such as the coronary arteries and the extremities.…”

“…In a previous study, we have determined the feasibility of using a hydraulic pressure wave to transfer high-force impulses over a distance of 1 m through 6F commercially available catheters (21). In this study, an experiment was performed in which the input and output impulses were recorded as a function of the catheter type, curvature, and output plunger travel distance.…”