Expandable cryoablation catheter

Abstract

The invention discloses an expandable cryoablation catheter. The catheter includes a catheter body, a sheath tube and a refrigerating device. The refrigerating device is arranged at and connected withthe distal end of the catheter body. The refrigerating device is composed of several refrigerating units. The distal ends of several refrigerating units are independent of each other, and the refrigerating unit can be restored to a set shape when released from the distal end of the sheath tube. The catheter body is movably arranged in a cavity of the sheath tube, the tail end of the catheter bodyis connected and communicated with the near ends of the refrigerating units, and when the catheter body and the sheath tube displace relatively, the distal ends of the refrigerating units displace synchronously relative to the distal end of the sheath tube to achieve expansion or contraction. The catheter can achieve full freezing in the circumferential direction of the natural cavity and also achieve uniform interval freezing in the circumferential direction of the natural cavity, in order to retain the important physiological function of the original cavity. Meanwhile the expansion and contraction stress of the refrigerating units can be reduced, and the influence of expansion and contraction on the shape change of the refrigerating units is reduced.

Description

technical field [0001] The invention relates to the technical field of cryoablation, in particular to an expandable cryoablation catheter. Background technique [0002] Intervention therapy in the natural cavity of the human body has attracted more and more attention, and there are more and more corresponding treatment devices and methods, and the clinical treatment effect has been widely recognized. At present, radiofrequency ablation is widely used and developed rapidly. Although successful in several areas, radiofrequency ablation has several major disadvantages, including incomplete ablation, often lack of visualization during catheterization, potential overlap during treatment (where some areas receive energy from other areas) twice), tissue charring and need for frequent debridement, frequent need for additional doses of energy after debridement, and potential perforation of body cavities or chambers due to the rigidity of RF electrodes. [0003] In view of the above...

AI Technical Summary

Problems solved by technology

[0004] However, in the application of the natural cavity of the human body, most of the existing cryoablation instruments perform cryoablation of the entire circumference area. It is a natural channel with cilia swinging and peristaltic functions), and there are defects in the application; for example, as a relatively common application method, the expandable part of the existing cryoablation catheter mostly adopts a balloon structure, and the balloon is formed in the balloon. Ultra-low temperature, through the contact between the balloon wall and the tissue for heat exchange, to achieve the purpose of ablation therapy. With this structure, all the contact area of ​​the balloon will be cryoablated. When used in the natural cavity, the entire cavity circumference (contact part) will be ablation, thereby causing damage to the vital physiological functions of the lumen

Moreover, the existing cryoablation technology also has the disadvantage of being subjected to a large force during expansion and contraction, and requires a large force to be applied during use, which is inconvenient for the operator; for example, as a relatively common application method, the existing The cryoablation catheter adopts a cryounit with an expandable structure, most of which are equipped with a central mandrel and a sheath. Connection, when the freezing unit expands or contracts, the force on the mandrel is very large, which may easily lead to deformation or even breakage of the mandrel, resulting in a relatively large force of expansion and contraction of the freezing unit. At the same time, the shape change of the freezing unit is limited by the mandrel , the shape of the predetermined expansion and contraction is prone to change

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