CN114288007B

CN114288007B - Fluid injection device and cryoballoon catheter

Info

Publication number: CN114288007B
Application number: CN202111670959.2A
Authority: CN
Inventors: 彭博; 孙忠旭; 龚杰; 冯骥
Original assignee: Synaptic Medical Beijing Co Ltd
Current assignee: Synaptic Medical Beijing Co Ltd
Priority date: 2021-12-31
Filing date: 2021-12-31
Publication date: 2022-09-30
Anticipated expiration: 2041-12-31
Also published as: WO2023124070A1; CN114288007A

Abstract

The invention provides a fluid injection device and a freezing balloon catheter, wherein the fluid injection device comprises a cylinder body, a fluid channel is fixedly arranged on the cylinder body, a fluid inlet and a fluid outlet of the fluid channel are both communicated with the outside, the fluid outlet comprises at least two injection units, the injection units are arranged on at least one radial plane of the sleeve, the injection units on the same radial plane are at least two and are uniformly arranged at intervals, and the sum of the cross sectional areas of the injection units is smaller than the cross sectional area of the fluid inlet. The embodiment of the invention can solve the problem of uneven injection of the refrigerant in the prior art on the premise of meeting the requirement of a cryoablation balloon catheter assembly structure.

Description

Fluid injection device and cryoballoon catheter

Technical Field

The invention relates to the technical field of cryoablation instruments, in particular to a fluid injection device and a cryoballoon catheter.

Background

Atrial Fibrillation (AF) is one of the most common cardiac arrhythmias in clinical practice. According to estimates, there are 3300 more than ten thousand people worldwide with AF. According to the published Chinese data in 2004, the prevalence rate of AF of residents in China between 30 and 85 years old is 0.77 percent, wherein the prevalence rate of people over 80 years old is over 30 percent. The incidence of AF increases with age, and compared with non-atrial fibrillation patients of the same age, the atrial fibrillation patients are often poorer in quality of life and often accompanied by diseases such as hypertension, heart failure and the like, so that thromboembolic complications and mortality of the patients are higher. Recent studies have linked AF to the development of dementia. Therefore, the effective treatment of atrial fibrillation has important clinical significance. In long-term follow-up care, control of atrial fibrillation by intervention has been shown to improve quality of life.

For patients with paroxysmal atrial fibrillation, the freezing balloon ablation is adopted for treatment, and the method has higher safety: the tissue damage focus formed by the cryoablation is more uniform, the boundary is clearer, eschar, vaporization burst and collagen degeneration contracture related to high temperature effect are not caused, the integrity of tissue cells is kept to the maximum extent, and the risk of serious complications such as thrombosis, pulmonary vein stenosis, heart perforation, atrioesophageal fistula and the like can be reduced theoretically; the balloon catheter is adhered to the ablation tissue in the process of cryoablation, the catheter has small displacement, and the ablation safety is improved; before cryogenic cryoablation, the cryogenic energy source can cause transient and reversible damage to the tissue, significantly reducing the risk of permanent damage to vital tissues.

The conventional ablation instrument adopts a cascade refrigeration mode, N ₂ And the low-temperature working medium passes through the precise pipeline of the device, passes through the coaxial fluid connecting pipe and the catheter body and reaches the far-end balloon. Low temperature state N ₂ The O absorbs heat in the saccule by phase change evaporation effect, so as to reach the cryoablation temperature enough to cause the necrosis of myocardial tissue and achieve the purpose of cooling ablation. The steam after heat exchange with the cardiac muscle returns to the interior of the cryoablation instrument through the catheter body and the coaxial fluid connecting pipe. The interior of the apparatus is maintained in a vacuum environment using a vacuum pump and the vapor is ultimately discharged to the exhaust system of the hospital.

The cryoablation balloon catheter is connected with a cryoablation instrument for cryoablation treatment of cardiac muscle tissue, the spherical balloon is used for being attached to the left atrium pulmonary vein opening, and low-temperature working medium is sprayed to the surface of the balloon through a plurality of nozzles inside the balloon, gasified and expanded for refrigeration. The refrigeration area forms a ring shape and is basically overlapped with the target treatment part of the cardiac muscle, so that the cryoablation energy transfer is more concentrated, the refrigeration loss is lower, and the risk of cryocomplications is reduced. Temperature sensor is built-in to the sacculus, real-time supervision treatment temperature, and built-in pressure sensor of pipe handle and opto-coupler sensor, the integrality of real-time supervision sacculus avoids low temperature working medium to leak and gets into blood, but the pipe head end bidirectional bending leans on and pastes intracardiac target treatment position.

The specific scheme of the prior art is as follows: the existing freezing balloon catheter generally comprises a main body tube of a slender tubular structure, a matching instrument (such as a guide wire or a mapping catheter) is sleeved in an inner cavity of the main body tube in a sliding mode, an inner balloon and an outer balloon are sequentially sleeved outside the main body tube, a double-layer freezing balloon is formed by the far end of the inner balloon and the far end of the outer balloon, and the inner balloon and the outer balloon are tightly attached through vacuumizing. When the inner balloon is gradually filled with refrigerant fluid (e.g. liquid laughing gas N) ₂ O), the cryoballoon appears to approximate an ellipsoid. Freezing sacculeA temperature sensor fixedly connected with the main tube is arranged in the freezing sacculus for measuring the temperature change in the freezing sacculus.

The main body of the injection device is a hollow tube body (generally nickel titanium or polyimide) with a closed blind end at the far end, the main body extends along the axis direction of the main tube, the near end of the main body is a refrigerating working medium fluid inlet, the far end of the main body is in a spiral structure and is fixedly assembled with the main tube, and the outermost circumferential surface of the spiral structure is provided with injection holes. When the freezing saccule needs to be inflated, the refrigerating working medium fluid enters from the near end of the injection device and flows to the far end of the injection device, and is sprayed out from the spray hole to the hemisphere at the far end of the freezing saccule for cryoablation. In practical use, the first jet hole has the worst refrigerating working medium jet state and the minimum flow, and the second jet hole has the best refrigerating working medium jet state and the maximum flow.

According to the Bernoulli principle, the ideal total fluid pressure = dynamic pressure + static pressure + gravitational potential energy, and the total fluid pressure in each position in the pipeline is unchanged. Constraint conditions are as follows: the fluid is incompressible; the sum of the sectional areas of all the injection holes is smaller than the sectional area of the hollow pipe body; the pressure of the refrigerant flowing into the hollow pipe body is enough; neglecting the flow resistance of the inner wall of the hollow tube body. And when the total pressure at each part of the spiral part in the hollow pipe body is approximately equal, the refrigerating working medium in the hollow pipe body has the fastest flow velocity, the largest dynamic pressure and the smallest static pressure at the first injection hole, and has the slowest flow velocity, the smallest dynamic pressure and the largest static pressure at the second injection hole.

The factor determining the injection state/flow rate of the injection hole is the static pressure difference between the inside and outside of the injection hole. When the static pressure outside the jet hole is unchanged, the larger the static pressure in the jet hole is, the better the jet state is and the larger the flow rate is; and vice versa. Therefore, the injection state of the refrigerant of the first injection hole is the worst and the flow rate is the minimum, and the injection state of the refrigerant of the first injection hole is the best and the flow rate is the maximum.

In view of this, in practical applications, in order to ensure that the cooling capacity of the distal end surface of the cryoballoon is substantially uniform in the circumferential direction and to reduce the negative effects caused by the inconsistency of the above-mentioned injection states, the arrangement of the small holes 1-N needs to be adjusted as follows (taking 8 small holes as an example): each hole is at an interval of 135 degrees in the circumferential direction of the spiral line, so that the small holes are uniformly distributed at an interval of 45 degrees in the axial projection direction of the main body pipe. In addition, in the axial projection direction of the main body pipe, the small holes with good injection states and the small holes with poor injection states are alternately arranged, so that the uneven distribution of the refrigeration working medium injection caused by flow difference is improved.

In the prior art, small holes with good spraying states and small holes with poor spraying states are alternately arranged, but absolute uniformity of the spraying states cannot be achieved. For example, the ejection state of the combination of the first orifice and the fourth orifice is inevitably inferior to the ejection state of the fifth orifice and the eighth orifice.

Taking 8 holes as an example, when the holes are arranged at 135 degrees (or, if the hole pitch is 1, 3, 5, 7 … … odd times of 45 degrees), the 8 holes will be located in different cross sections of the spiral line, and the larger the multiple is, the farther the distance between the cross section of the first hole and the cross section of the eighth hole is. Alternatively, the 8 holes cannot fall in the same plane perpendicular to the main body tube.

After the refrigeration working medium is sprayed out from the small hole, the distance from the small hole to the surface of the saccule has obvious difference because the spraying direction of the small hole is positioned on different cross sections of the spiral line. The refrigerant is gasified and expanded after being sprayed to the surface of the balloon, and the effective refrigeration is realized. The refrigerant does not reach the surface of the balloon and is partially or fully vaporized, which is considered to be inefficient or ineffective refrigeration. The further the aperture is from the balloon surface, the more likely it will vaporize and expand before being ejected onto the balloon surface, resulting in inefficient or ineffective cooling. The worst-case orifice is furthest from the balloon surface and the best-case orifice is closest to the balloon surface, further exacerbating the problem of uneven cooling of the balloon distal surface.

Disclosure of Invention

In view of this, the embodiments of the present disclosure provide a fluid injection device and a freezing balloon catheter, so as to solve the problem of uneven injection of a refrigerant, thereby avoiding uneven tissue cryoablation effect caused by uneven injection of the refrigerant, even poor tissue potential isolation effect caused by ablation leak, and thus reducing effectiveness of cryoablation, so that a recurrence rate of atrial fibrillation after treatment is high.

The embodiment of the specification provides the following technical scheme: a fluid injection device comprises a cylinder body, wherein a fluid channel is fixedly arranged on the cylinder body, a fluid inlet and a fluid outlet of the fluid channel are both communicated with the outside, the fluid outlet comprises at least two injection units, the injection units are arranged on at least one radial plane of the sleeve, the injection units on the same radial plane are at least two and are uniformly arranged at intervals, and the sum of the cross sectional areas of the injection units is smaller than that of the fluid inlet.

Furthermore, the cylinder body is provided with a circular ring radial section, and the fluid channel is arranged inside the pipe wall of the cylinder body; or the cylinder body is provided with a circular radial section, and the fluid channel is fixedly arranged outside the pipe wall of the cylinder body; and/or the fluid passages are distributed in axial symmetry relative to the axis of the cylinder body or in mirror symmetry relative to the axial section of the cylinder body; and/or the spraying units are distributed in axial symmetry relative to the axis of the cylinder or in mirror symmetry relative to the axial section of the cylinder; and/or the fluid inlet is positioned on the end surface of the cylinder body; and/or each injection unit comprises at least one radial injection hole or at least one radial injection slit.

Further, the fluid channel comprises at least one first branching unit; when the fluid passage comprises a first branch unit, the first branch unit is in mirror symmetry with respect to the axial section of the cylinder; alternatively, when the fluid passage comprises at least two first branching units, each first branching unit is rotationally symmetric with respect to the axis of the cylinder.

Furthermore, the first branch unit is provided with a first main path and first branch paths, the inlets of the first branch paths are arranged in the middle of the first branch paths, the outlets of the first branch paths are arranged at two ends of the first branch paths, the outlets of the two first branch paths are in central symmetry or axial symmetry distribution relative to the first main path, the outlets of the first main path are connected with the inlets of the first branch paths, and the extending direction of the first main path is parallel to the axis of the cylinder; the injection unit comprises two radial injection holes which are arranged on the outer wall of the cylinder at intervals, the two radial injection holes correspond to and are communicated with the positions of the first branch paths, and the axial distances from the two radial injection holes to the first main path are equal; the sectional area of the radial injection hole is smaller than or equal to that of the first branch, and the sectional area of the first main path is larger than or equal to 2 times of that of the first branch.

Furthermore, the fluid channel comprises a second branch unit, the second branch unit comprises a second main path and second branch paths, inlets of the second branch paths are arranged in the middle of the second branch paths, outlets of the second branch paths are arranged at two ends of the second branch paths, outlets of the two second branch paths are in central symmetry or axial symmetry distribution relative to the second main path, outlets of the second main path are connected with inlets of the second branch paths, the extending direction of the second main path is parallel to the axis of the cylinder, outlets of the two second branch paths are in one-to-one correspondence with the two first branch units and/or outlets of each second branch path are correspondingly connected with the two first branch units, and the two first branch units connected to the outlet of the same second branch path are in axial symmetry distribution relative to the second branch paths; the sectional area of the second branch circuit is larger than or equal to that of the first main circuit, and the sectional area of the second main circuit is larger than or equal to 2 times of that of the second branch circuit.

Furthermore, the fluid injection device further comprises a third branch unit, the third branch unit comprises a third main path and third branch paths, the inlet of each third branch path is arranged in the middle of the third branch path, the outlets of the third branch paths are arranged at two ends of the third branch path, the outlets of the two third branch paths are in central symmetry or axial symmetry distribution relative to the third main path, the outlet of the third main path is connected with the inlet of the third branch path, the extending direction of the third main path is parallel to the axis of the cylinder, and the outlets of the two third branch paths are correspondingly connected with the two second branch units one by one; the sectional area of the third branch circuit is larger than or equal to that of the second main circuit, and the sectional area of the third main circuit is larger than or equal to 2 times of that of the third branch circuit.

Furthermore, the number of the third branch units is at least two, and the at least two third branch units are uniformly distributed at intervals along the circumferential direction of the cylinder.

Further, the cross-sectional size of the spray unit ranges from 0.05 to 3 mm.

The invention also provides a freezing balloon catheter which comprises the fluid injection device.

Further, the freezing balloon catheter comprises a main body tube and a fluid tube, wherein the main body tube is arranged in an inner hole of the cylinder in a penetrating mode; when the fluid injection device is provided with only the first branch unit, the outlet of the fluid pipe is in sealing connection with the fluid inlet of the first branch unit; when the fluid injection device only has the first branch unit and the second branch unit, the outlet of the fluid pipe is in sealing connection with the fluid inlet of the second branch unit; when the fluid injection device has the first branch unit, the second branch unit and the third branch unit, the outlet of the fluid pipe is hermetically connected with the fluid inlet of the third branch unit.

Compared with the prior art, the beneficial effects that can be achieved by the at least one technical scheme adopted by the embodiment of the specification at least comprise: in the embodiment of the invention, the injection units are arranged on at least one radial plane of the sleeve, at least two injection units positioned on the same radial plane are uniformly arranged at intervals, and the sum of the cross sectional areas of all the injection units is smaller than the cross sectional area of the fluid inlet, so that the distances from each radial injection hole to the surface of the freezing saccule are basically equal, namely, the refrigerating working medium can be uniformly injected to the surface of the saccule in the same plane, and the distances of gasification paths are equal, namely, the dynamic pressure and the static pressure of the refrigerating working medium sprayed by the two radial injection holes can be basically equal in the embodiment, thereby solving the problem of uneven injection of the refrigerating working medium in the prior art on the premise of meeting the assembly structure of the cryoablation saccule catheter.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic structural diagram of an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a first branch unit, a second branch unit and a third branch unit on an inner barrel according to an embodiment of the present invention;

FIG. 3 is a barrel structure formed by a 3D printing technology in an embodiment of the invention;

FIG. 4 is a schematic three-dimensional structure of multiple embodiments of branching units in accordance with embodiments of the present invention;

FIG. 5 is a front view of FIG. 4;

FIG. 6 is a side view of FIG. 4;

FIG. 7 is an expanded view of the first branch unit, the second branch unit, and the third branch unit according to an embodiment of the present invention;

FIG. 8 is a schematic diagram showing the first branch unit, the second branch unit and the third branch unit in another embodiment of the present invention;

FIG. 9 is a schematic structural view of a cryoballoon catheter in accordance with an embodiment of the present invention;

FIG. 10 is a prior art freezing effect diagram;

FIG. 11 is a graph showing the freezing effect of the embodiment of the present invention.

Reference numbers in the figures: 10. a barrel; 11. a first main road; 12. a first branch; 13. a second main road; 14. a second branch circuit; 15. a third main path; 16. a third branch; 21. a radial injection hole; 31. a main body tube; 32. a fluid pipe.

Detailed Description

The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

As shown in fig. 1 to 9, an embodiment of the present invention provides a fluid injection apparatus, which includes a cylinder 10, a fluid channel is fixedly disposed on the cylinder 10, a fluid inlet and a fluid outlet of the fluid channel are both communicated with the outside, and the fluid outlet includes at least two injection units, where the at least two injection units are disposed on at least one radial plane of the sleeve, at least two injection units located on the same radial plane are uniformly spaced, and a sum of cross-sectional areas of the injection units (all injection units) is smaller than a cross-sectional area of the fluid inlet.

In the embodiment of the invention, the injection units are arranged on at least one radial plane of the sleeve, at least two injection units positioned on the same radial plane are uniformly arranged at intervals, the sum of the cross sectional areas of the injection units is smaller than the cross sectional area of the fluid inlet, and the distance from each injection unit to the surface of the freezing saccule is basically equal, so that the refrigeration working medium can be uniformly injected to the surface of the saccule in the same plane, the distance of gasification paths is equal, and the problem of nonuniform injection of the refrigeration working medium is solved. Meanwhile, the sum of the cross-sectional areas of the jetting units is smaller than the cross-sectional area of the fluid inlet, so that the effect of avoiding the generation of fluid turbulence can be realized. When the refrigerant injection is not uniform, the tissue in contact with the cryoballoon surface (e.g., the pulmonary vein ostia) receives non-uniform ablation energy. In this case, after the cryoballoon performs ablation on the tissue (e.g., the pulmonary vein ostium), the tissue ablation result may be uneven, for example, when a part of the tissue is ablated too much, the tissue is still ablated in place, and even when a leak occurs during ablation. If the ablation is excessive, the esophagus, the phrenic nerve and even the brain can be damaged. If the ablation is not in place, the electrical isolation effect of the tissue is poor, and the expected ablation purpose cannot be achieved. This not only reduces the effectiveness of cryoablation, but also increases the recurrence rate after atrial fibrillation treatment. The problem that the refrigerant sprays unevenly can be effectively solved to this application to effectively improve the homogeneity of cryoablation, improve the validity of cryoablation, and reduce the recurrence rate of treatment.

In one embodiment, the cylinder 10 has a circular radial cross-section, and the fluid passage is embedded inside the wall of the cylinder 10. The cylinder 10 is of a sleeve-like structure with openings at both ends, the fluid channel is located between the inner and outer tube walls of the cylinder 10, and the injection unit is connected to the outside. In another embodiment, the cylinder 10 has a circular radial cross section, and the fluid passage is fixed outside the tube wall of the cylinder 10; that is, the fluid passage is a solid pipe and is fixedly disposed along the outer circumference of the cylinder 10, and the injection unit is disposed on the outer side surface of the fluid passage.

In another embodiment, the cylinder 10 has a circular radial cross section, and a fluid flow channel with a circular radial cross section is provided, and at least two injection units located in the same radial direction are opened on the cylinder 10.

Preferably, the spray units are distributed in axial symmetry with respect to the axis of the cylinder 10 or in mirror symmetry with respect to an axial section of the cylinder 10. Each spray unit comprises at least one radial spray hole 21 or at least one radial spray slit.

The arrangement of the injection units can uniformly inject the refrigerant in the fluid channel to a set position, and the selection number and the selection structure of the injection units in the embodiment can be selected according to different requirements.

It should be noted that the fluid inlet in this embodiment is located on the end face of the cylinder 10, and the external supply fluid pipe of the fluid inlet is communicated with the fluid channel for supplying the refrigerant to the fluid channel through the supply fluid pipe. Of course, the position of the fluid inlet is not limited to the end surface of the cylinder 10, and the fluid inlet may be disposed on the side wall of the cylinder 10 when there are different requirements.

When the spray unit is centrosymmetric with respect to the axis of the cartridge 10 or mirror-symmetric with respect to the axial section of the cartridge 10, the fluid passage is centrosymmetric with respect to the axis of the cartridge 10 or mirror-symmetric with respect to the generatrix of the cartridge 10. The injection unit is illustrated as being centrosymmetric with respect to the axis of the cylinder 10: the plurality of injection units are uniformly distributed along the outer circumference of the cylinder 10 at intervals, and the plurality of injection units are located in the same radial plane to form central symmetry distribution. The injection unit is illustrated as being mirror symmetrical with respect to the axial section of the cartridge 10: the spraying units are arranged in two symmetrical radial planes respectively, the two symmetrical radial planes are distributed in mirror symmetry relative to the axial section, and the spraying units are uniformly distributed in the respective radial planes at intervals.

The fluid passage is illustrated as being centrosymmetric with respect to the axis of the cylinder 10: the fluid passages may be a plurality of fluid passages, and are uniformly distributed along the outer circumference of the cylinder 10 at intervals, and each fluid passage has the same structure, and the plurality of fluid passages are axially symmetrically arranged with respect to the axis of the cylinder 10. The fluid channels are illustrated in mirror symmetry with respect to the generatrices of the cartridge 10: the two fluid passages are of the same structure and are symmetrically arranged on two sides of a generatrix of the cylinder body 10. The moving line forming the curved surface is referred to as a generatrix, and when the cylinder 10 is a cylinder in this embodiment, the generatrix is a straight line parallel to the axis. The above examples do not limit the present application in any way, but merely represent one of the possible embodiments.

The symmetry of the fluid channels ensures the same flow length and flow cross section, thereby ensuring the same dynamic pressure and finally realizing the same static pressure.

Specifically, the fluid channel includes at least one first branching unit; when the fluid passage includes a first branch unit, the first branch unit is mirror-symmetrical with respect to the axial section of the cylinder 10; alternatively, when the fluid passage includes at least two first branch units, each first branch unit is rotationally symmetric with respect to the axis of the cylinder 10. The first branch unit is provided with a first main path 11 and a first branch path 12, an inlet of the first branch path 12 is arranged in the middle of the first branch path 12, outlets of the first branch path 12 are arranged at two ends of the first branch path 12, outlets of the two first branch paths 12 are in central symmetry or axial symmetry distribution relative to the first main path 11, an outlet of the first main path 11 is connected with the inlet of the first branch path 12, and the extending direction of the first main path 11 is parallel to the axis of the cylinder 10; the injection unit includes two radial injection holes 21, and two radial injection holes 21 interval settings are at the outer wall of barrel 10, and two radial injection holes 21 correspond and communicate with first branch 12 place position, and two radial injection holes 21 are equal apart from the axis distance of first main way 11, and the sectional area of radial injection hole 21 is less than or equal to the sectional area of first branch 12, and the sectional area of first main way 11 is greater than or equal to 2 times of the sectional area of first branch 12. In a preferred embodiment, the cross-sectional area of the radial injection holes 21 is approximately equal to the cross-sectional area of the first branch 12, and the cross-sectional area of the first main path 11 is greater than or equal to 2 times the cross-sectional area of the first branch 12.

In the embodiment of the invention, the two radial injection holes 21 are positioned at the positions of the first branch path 12 and have equal distance from the axis of the first main path 11, so that the distance from each radial injection hole to the surface of the freezing saccule is basically equal, namely, the refrigeration working medium can be uniformly injected to the surface of the saccule in the same plane, and the distance of gasification paths is equal, namely, the dynamic pressure and the static pressure of the refrigeration working medium injected by the two radial injection holes 21 can be basically equal in the embodiment, thereby solving the problem of uneven injection of the refrigeration working medium in the prior art on the premise of meeting the assembly structure of the cryoablation saccule conduit.

The dynamic pressure and the static pressure are equal because the flow directions of the refrigeration working medium are basically symmetrical, and the flow speeds of the refrigeration working medium in the sub fluid pipelines of the same stage number are equal, so that the dynamic pressure and the static pressure of the refrigeration working medium sprayed out from the two radial spray holes 21 are equal.

In the embodiment of the present invention, the extending direction of the first main passage 11 is parallel to the axial direction of the cylinder 10, that is, the overall shape of the first branch unit may be a T shape or a Y shape (an axisymmetric pattern). Or the shape of the first branch 12 may be S-shaped, the outlet of the first main branch 11 being connected in the central position of the S-shape (central symmetrical pattern).

The present invention further has the following embodiment, the number of the first branch lines 12 may be two, two first branch lines 12 form an X-shaped structure, the first main line 11 is a straight line, and an outlet of the first main line 11 is connected to a central position of the X-shaped structure. Or the number of the first branch circuits 12 may be two, two ends of the first main circuit 11 are both outlets, the middle of the first main circuit 11 is an inlet, and the outlets at two ends of the first main circuit 11 are both correspondingly connected with one first branch circuit 12, that is, the overall shape of the first branch unit is i-shaped.

Of course, in different embodiments, the first main path 11 may also be a curved path, and the above embodiments may also be combined with each other.

The fluid channel in the embodiment of the present invention includes a second branch unit, the second branch unit includes a second main path 13 and second branch paths 14, an inlet of the second branch path 14 is disposed in the middle of the second branch path 14, outlets of the second branch paths 14 are disposed at two end portions of the second branch path 14, outlets of the two second branch paths 14 are distributed in a central symmetry or an axial symmetry with respect to the second main path 13, an outlet of the second main path 13 is connected with an inlet of the second branch path 14, an extending direction of the second main path 13 is parallel to an axis of the cylinder 10, and outlets of the two second branch paths 14 are connected with the two first branch units in a one-to-one correspondence manner.

The cross-sectional area of the second branch 14 is greater than or equal to the cross-sectional area of the first main path 11, and the cross-sectional area of the second main path 13 is greater than or equal to 2 times the cross-sectional area of the second branch 14. In a preferred embodiment, the cross-sectional area of the second branch 14 is approximately equal to the cross-sectional area of the first main path 11, and the cross-sectional area of the second main path 13 is greater than or equal to 2 times the cross-sectional area of the second branch 14.

The structure of the second main path 13 and the second branch path 14 may adopt the structure of the first branch unit in the above embodiment, such as a T shape or a Y shape. The diameter of the pipe in the second branch unit should be greater than or equal to that of the pipe in the first branch unit, so that it can be ensured that the flow rate of the fluid and the injection pressure of the radial injection holes 21 in the following branch unit can reach set values.

In another embodiment of the present invention, the outlet of each second branch 14 is connected to the first fluid inlets of two first branch units, and the two first branch units connected to the outlet of the same second branch 14 are distributed in an axisymmetric manner with respect to the corresponding second branch 14.

In the above embodiment, the first branches 12 of the first branch unit are arranged in two rows and are parallel at intervals, so that the corresponding injection units are also arranged in two rows at intervals, and the distances from each radial injection hole 21 of the two rows of injection units to the surface of the freezing balloon are basically equal, that is, the refrigeration working medium can be uniformly injected to the surface of the balloon in the same plane, and the distances of the gasification paths are equal.

Preferably, according to different selection requirements, at least two second branch units may be provided in the embodiments of the present invention, and the purpose of providing the at least two second branch units is to increase the number of the spray units located in the same radial cross section, so as to change the arrangement density of the spray units in the circumferential direction, and achieve a preset freezing effect.

In this embodiment, at least two second branch units are uniformly distributed at intervals along the circumferential direction of the cylinder 10, and the flow rate of the fluid inlet of each second branch unit are the same, so that the inlet flow rate and the flow rate of each second branch unit are the same.

More preferably, the fluid injection device further comprises a third branch unit, the third branch unit comprises a third main path 15 and third branches 16, the inlet of the third branch 16 is arranged in the middle of the third branch 16, the outlets of the third branch 16 are arranged at two ends of the third branch 16, the outlets of the two third branches 16 are distributed in central symmetry or axial symmetry relative to the third main path 15, the outlet of the third main path 15 is connected with the inlet of the third branch 16, the extending direction of the third main path 15 is parallel to the axis of the cylinder 10, and the outlets of the two third branches 16 are connected with the second fluid inlets of the two second branch units in a one-to-one correspondence manner.

The number of the third branch units is at least two, and the at least two third branch units are uniformly distributed at intervals along the circumferential direction of the cylinder 10. The cross-sectional area of the third branch 16 is greater than or equal to the cross-sectional area of the second main path 13, and the cross-sectional area of the third main path 15 is greater than or equal to 2 times the cross-sectional area of the third branch 16. In a preferred embodiment, the cross-sectional area of the third branch 16 is approximately equal to the cross-sectional area of the second main path 13, and the cross-sectional area of the third main path 15 is greater than or equal to 2 times the cross-sectional area of the third branch 16.

It should be noted that the first branch 12, the second branch 14 and the third branch 16 may be a straight line or a curved line.

For example, in the embodiment of the present invention, the first branch 12 and the second branch 14 are straight branches, the third branch 16 is a curved branch, the third branch 16 includes two parallel straight-line segments arranged at intervals and a connecting segment, and both ends of the connecting segment are connected to the same end of the two straight-line segments. The third branch 16 is configured as described above to reduce the influence of the third branch 16 on the dynamic pressure and static pressure of the refrigerant, so as to achieve the predetermined purpose.

The first branch 12, the second branch 14 and the third branch 16 may be in the same structure or in a combination of different structures, all that is needed is to satisfy the same restriction of the flow resistance in the above embodiments.

The diameter of the cross section of the radial injection hole 21 in the embodiment of the present invention ranges from 0.05mm to 3 mm. The embodiment of the invention is applied to the situation of small pipeline diameter, so the influence caused by pipe wall damping can be effectively reduced by adopting the tree-shaped symmetrical structure of the embodiment of the invention, and the embodiment of the invention can achieve the aim of uniform spraying. Meanwhile, the embodiment of the invention realizes uniform injection through the structure and reduces the difficulty of liquid pressure control, and compared with the liquid pressure control of the existing freezing saccule, the embodiment of the invention has lower requirement on the liquid pressure control.

Due to the specific application of cryoablation balloon catheters, the radial jet holes 21 are required to be relatively small in size, typically no larger than a few millimeters. As for the current state of the industry, the thickness is generally below 3 mm. The radial jet holes 21 are arranged on the outer wall of the cylinder body 10, and other medical instruments are matched in the through cavity of the cylinder body 10. In addition, the radial injection holes 21 are directed straight into the body, such as at the pulmonary vein ostia, and the injected fluid cannot be too thick. This means that the space that can be arranged on the cartridge 10 is limited. The final spray effect must be guaranteed by the complete structure and manufacturing process. Also, since the present embodiment employs the joule thomson effect, that is, the cryogenic liquid delivered to the balloon catheter from the device is subjected to injection, vaporization and volume expansion for cooling. The cooling method employed in this example is substantially different from the cooling method without state transition which is generally used industrially.

Meanwhile, the fluid adopted in the embodiment of the invention is liquid, and the flow characteristic of the fluid is more complicated than that of gas. Therefore, the external size of the fluid injection device in the embodiment is limited, the size of the inner cavity is limited, the structure of the flow channel is limited, and the shape and the position of the radial spray holes are limited, so that the combination of the factors determines the final performance and the effect of the fluid injection device.

The sizes of the first main path 11, the first branch path 12, the second main path 13, the second branch path 14, the third main path 15 and the third branch path 16 in this embodiment are determined by the operation and the physiological structure of the human body, for example, the cardiac electrophysiology operation is to go the inferior vena cava into the human body, and the sizes of the first main path 11, the first branch path 12, the second main path 13, the second branch path 14, the third main path 15 and the third branch path 16 (which may be collectively referred to as a fluid channel) are all reversely pushed step by step. Examples are as follows: the vein has an internal diameter of 15 mm, the diameter of the sheath contained in that vein may be 5mm, and by pushing backwards the external diameter of the fluid channel may be 4 mm, and by subtracting the thickness of the outer balloon dimension, the size of the radial ejection holes 21 is 3 mm.

Of course, the radial injection holes 21 are typically less than 1mm, such as 0.05mm, 0.06mm or 0.07mm, except that the radial injection holes 21 satisfy the above-mentioned limitation of the sum of the areas.

The embodiment of the invention realizes uniform injection through the structure, reduces the difficulty of liquid pressure control, and has lower requirements on liquid pressure control compared with the liquid pressure control of the existing freezing saccule.

As shown in fig. 3, the cylinder 10 in the embodiment of the present invention may be integrally formed by using a 3D printing technology, and may also be of a split structure. The cylinder 10 of the split structure comprises an inner cylinder and an outer cylinder, and the outer wall of the inner cylinder is provided with the groove-shaped first branch unit, the groove-shaped second branch unit and the groove-shaped third branch unit. The distribution is the same as the above embodiments, and will not be described herein. The outer cylinder may be provided with the radial injection holes 21, and each of the radial injection holes 21 is in corresponding communication with a corresponding first branch unit. The near end sections and the far end faces of the inner cylinder and the outer cylinder are welded or bonded.

In the present embodiment, the number of fluid inlets is denoted by NA, and the number of radial injection holes 21 is denoted by NB. Wherein:

NA =2n, and n is more than or equal to 0. Preferably n =0 or n =1, i.e. NA =1 or 2. For example NA = 1/2/4.

NB =2n, n ≧ 2. Preferably n =3, i.e. NB = 8. E.g., NB = 4/8/16. If the number of radial injection holes 21 is too large, the cross section of the individual radial injection holes 21 is reduced accordingly, but the problem of clogging due to too small an area of the radial injection holes 21 is avoided. And the total area of all radial injection holes 21 on each tree branch should be smaller than the area of the fluid inlet.

The radial injection holes 21 may be a circular hole-shaped nozzle, a straight-shaped nozzle, a tapered nozzle, or the like of the related art. All kinds of injection modes or combinations that can meet the injection requirements should be within the protection scope of the present application, and are not illustrated herein.

The radial injection holes 21 in the present embodiment may be configured in the same manner or in a combination of the above shapes, on the premise of ensuring the uniform injection hole areas.

It should be noted that the radial injection holes 21 in the embodiment of the present invention are disposed at the first branch 12 of the fluid pipeline, i.e. the stage closest to the far end, and the position of the fluid pipeline at this stage has the minimum dynamic pressure and the maximum static pressure, i.e. the flow rate of the refrigerant injected from each radial injection hole 21 is approximately equal. Of course, the arrangement at the second branch 14 or the third branch 16 is also conceivable according to different requirements.

Further, the outer cylinder may be provided with a positioning hole corresponding in position to the fluid inlet (which may be the first main path 11, the second main path 13, or the third main path 15) for assembling the outer cylinder and the inner cylinder so that each radial injection hole 21 communicates with the preset first branch path 12.

The embodiment of the invention also provides a freezing balloon catheter which comprises the fluid injection device, wherein the freezing balloon catheter comprises a main body tube 31 and a fluid tube 32, and the main body tube 31 is arranged in the inner hole of the cylinder 10 in a penetrating manner.

The fluid injection device in this embodiment may be sleeved outside the main tube 31, and the fluid injection device and the main tube 31 may be connected by welding, bonding, or other fixed connection methods, or may be provided in a form that the fluid injection device can slide relative to the main tube 31.

Or a limiting part is arranged on the main tube 31, and the fluid injection device can be clamped and limited with the limiting part when being arranged on the main tube 31 in a penetrating way, so that the axial displacement of the fluid injection device is limited.

When the fluid ejection device in the embodiment of the present invention has only the first branch unit, the outlet of the fluid pipe 32 is sealingly connected to the fluid inlet of the first branch unit;

when the fluid ejection device has only a first branch unit and a second branch unit, the outlet of the fluid pipe 32 is sealingly connected with the fluid inlet of the second branch unit;

when the fluid ejection device has a first branching unit, a second branching unit, and a third branching unit, the outlet of the fluid pipe 32 is sealingly connected with the fluid inlet of the third branching unit.

The fluid pipe 32 is used for providing the refrigerant for the fluid injection device, the number of the fluid pipes 32 in the embodiment of the present invention is at least one, and a plurality of fluid pipes can be selected according to different requirements, and the flow rate of each fluid pipe 32 should be the same.

As shown in fig. 10 and 11, the freezing effect of the prior art is seen in fig. 10, the frozen area is not uniform, and the freezing effect of the present application is seen in fig. 11, the freezing effect of the present application is seen to present a symmetrical eight-petal shape, compared with the prior art, the present application has the following advantages from the freezing effect level: the application can avoid that the cryoablation effect of the tissue is uneven because the refrigerant sprays unevenly, even produces and melts the leak source, leads to the tissue potential to keep apart the effect not good to reduce the validity of cryoablation, so that treat the higher problem of recurrence rate of the back atrial fibrillation.

The above description is only exemplary of the invention and should not be taken as limiting the scope of the invention, so that the invention is intended to cover all modifications and equivalents of the embodiments described herein. In addition, the technical features, the technical schemes and the technical schemes can be freely combined and used.

Claims

1. A fluid injection device is characterized by comprising a cylinder body (10), wherein a fluid channel is fixedly arranged on the cylinder body (10), a fluid inlet and a fluid outlet of the fluid channel are both communicated with the outside, the fluid outlet comprises at least two injection units, wherein,

the spraying units are arranged on at least one radial plane of the cylinder body (10), at least two spraying units positioned on the same radial plane are uniformly arranged at intervals, and the sum of the cross sectional areas of all the spraying units is smaller than the cross sectional area of the fluid inlet;

the fluid channel comprises at least one first branching unit; when the fluid channel comprises one of the first branch units, the first branch unit is in mirror symmetry with respect to the axial section of the cylinder (10); or, when the fluid channel comprises at least two first branch units, each first branch unit is rotationally symmetrical with respect to the axis of the cylinder (10);

first branching unit is provided with first main way (11) and first branch road (12), the entry setting of first branch road (12) is in first branch road (12) middle part, the export setting of first branch road (12) is at the both ends of first branch road (12), and the export of two first branch roads (12) is central symmetry or axisymmetric distribution for first main way (11), the export of first main way (11) is connected with the entry of first branch road (12), the extending direction of first main way (11) is parallel with the axis of barrel (10).

2. A fluid spraying device as claimed in claim 1, wherein the cartridge (10) has an annular radial cross-section and the fluid passage opens into the wall of the cartridge (10) or is fixed to the outside of the wall of the cartridge (10).

3. A fluid spraying device as claimed in claim 2, wherein each spraying unit comprises at least one radial spraying hole or at least one radial spraying slit.

4. A fluid ejection device as in claim 3, wherein the fluid inlet is located at an end face of the cartridge (10).

5. The fluid injection device according to any one of claims 2 to 4, wherein the injection unit comprises two radial injection holes (21), the two radial injection holes (21) are arranged on the outer wall of the cylinder (10) at intervals, the two radial injection holes (21) correspond to and are communicated with the position of the first branch (12), and the two radial injection holes (21) have equal distance from the axis of the first main path (11);

the cross-sectional area of the radial injection hole (21) is smaller than or equal to that of the first branch (12), and the cross-sectional area of the first main path (11) is larger than or equal to 2 times of that of the first branch (12).

6. A fluid ejection device according to claim 5, wherein the fluid channel includes a second branch unit including a second main path (13) and a second branch path (14),

the inlet of the second branch (14) is arranged in the middle of the second branch (14), the outlets of the second branch (14) are arranged at two ends of the second branch (14), the outlets of the two second branches (14) are distributed in central symmetry or axial symmetry relative to the second main path (13), the outlet of the second main path (13) is connected with the inlet of the second branch (14), the extending direction of the second main path (13) is parallel to the axis of the cylinder (10), the outlets of the two second branches (14) are correspondingly connected with the two first branch units one by one,

the cross-sectional area of the second branch (14) is greater than or equal to the cross-sectional area of the first main path (11), and the cross-sectional area of the second main path (13) is greater than or equal to 2 times the cross-sectional area of the second branch (14).

7. A fluid injection device according to claim 5, wherein the fluid channel comprises a second branch unit comprising a second main branch (13) and second branches (14), the outlet of each second branch (14) is connected to two of the first branch units, and the two first branch units connected to the outlet of the same second branch (14) are arranged in axial symmetry with respect to the second branch (14).

8. The fluid injection apparatus according to claim 6 or 7, further comprising a third branch unit, wherein the third branch unit comprises a third main path (15) and a third branch path (16), an inlet of the third branch path (16) is arranged in the middle of the third branch path (16), an outlet of the third branch path (16) is arranged at two ends of the third branch path (16), outlets of the two third branch paths (16) are arranged in a central symmetry or axial symmetry with respect to the third main path (15), an outlet of the third main path (15) is connected with the inlet of the third branch path (16), the third main path (15) extends in a direction parallel to the axis of the cylinder (10), and outlets of the two third branch paths (16) are connected with the two second branch units in a one-to-one correspondence;

the sectional area of the third branch (16) is larger than or equal to that of the second main path (13), and the sectional area of the third main path (15) is larger than or equal to 2 times of that of the third branch (16).

9. The fluid ejection device according to claim 8, wherein the number of the third branch units is at least two, and at least two of the third branch units are spaced apart from each other in a circumferential direction of the cylinder (10).

10. The fluid ejection device of claim 1, wherein the ejection unit has a cross-sectional dimension in a range of 0.05 to 3 mm.

11. A cryoballoon catheter comprising a fluid injection device, wherein the fluid injection device is as claimed in any one of claims 1 to 10.

12. The freezing balloon catheter as claimed in claim 11, which comprises a main body tube (31) and a fluid tube (32), wherein the main body tube (31) is arranged in the inner hole of the barrel body (10) in a penetrating way;

when the fluid ejection device is the fluid ejection device of claim 5, an outlet of a fluid tube (32) is sealingly connected with the fluid inlet of the first branching unit.

13. The freezing balloon catheter as claimed in claim 11, which comprises a main body tube (31) and a fluid tube (32), wherein the main body tube (31) is arranged in the inner hole of the barrel body (10) in a penetrating way;

when the fluid ejection device is the fluid ejection device of claims 6-7, an outlet of a fluid tube (32) is sealingly connected with the fluid inlet of the second branching unit.

14. The freezing balloon catheter as claimed in claim 11, which comprises a main body tube (31) and a fluid tube (32), wherein the main body tube (31) is arranged in the inner hole of the barrel body (10) in a penetrating way;

when the fluid ejection device is according to claims 8-9, an outlet of a fluid tube (32) is sealingly connected to the fluid inlet of the third branching unit.