Hydraulic analysis of the functional properties of saline-jet aspiration thrombectomy catheters

The purpose of this paper is to clarify the functional properties of a sali ne-jet aspiration thrombectomy catheter based on hydraulics. This catheter, developed by the authors, aspirates intravascular thrombi by means of the effect: of a high-speed jet. We have derived the relationships between Q(s) , Q(a) and p(n), where Q(s) is the water supply rate, Q(a) is the water asp iration rate and p(n) is the negative pressure created in the distal lumen of the catheter. The relationships are represented by simple equations usin g c(1) and c(2), where c(1) and c(2) are coefficients proper to the cathete r. We have obtained c(1) and c(2) experimentally for three types of cathete r with different distal shapes. Two practical conclusions are derived from this study. First, making a short taper at the distal end increases the neg ative pressure created and is advantageous for thrombus aspiration. Second, making the diameter of the inner tube and nozzle smaller is essential for improving the aspiration ability of the catheter.