Balloon, balloon dilatation catheter, and stent system

Abstract

The present invention provides a balloon, a balloon dilatation catheter, and a stent system, and in particular, provides a balloon, a balloon dilatation catheter and a stent system suitable for a bifurcated vascular lesion area. The balloon comprises a balloon body, a distal end body and a proximal end body; the distal end body comprises a first conical portion, the proximal end body comprises a second conical portion, and at least the cone angle α1 of the first conical portion and the diameter d of the balloon in a dilated state satisfy the following relational expression: α1=k1lnd+b1, wherein k1∈[11.009, 21.478], b1∈[7.98, 20.8], 5≤d≤16, and d is a positive integer. The balloon dilatation catheter comprises the balloon, a push tube and a catheter hub. By improving and optimizing the structure of the balloon itself, the present invention provides a balloon, a balloon dilatation catheter and a stent system which feature a simple structure, ease of manufacturing and industrial-scale production, low cost, clinical operability, and precise stent deployment and positioning capabilities, thereby significantly improving the positioning precision of the stent in bifurcated vascular lesion areas and the surgical success rate.

Description

Balloons, balloon dilatation catheters, and stent systems Technical Field

[0001] The present invention belongs to the technical field of medical devices, and in particular relates to a balloon, a balloon dilatation catheter and a corresponding stent system. Background Art

[0002] Over the past decade, with the increasing aging of my country's population and the rising incidence of diabetes, the prevalence of cardiovascular and peripheral vascular diseases has also been rising. Among vascular diseases, arteriovenous stenosis can directly endanger the patient's life. Treatments for arteriovenous stenosis include surgery and interventional therapy. Interventional therapy has been popular in recent years because it is simple, minimally invasive, can be performed repeatedly, and can maximize the preservation of vascular resources in hemodialysis patients. Interventional therapy refers to percutaneous transluminal angioplasty (PTA), which uses a balloon dilatation catheter to dilate the narrowed target blood vessel, or delivers a stent to be implanted, and expands the stent to support the narrowed target blood vessel, thereby restoring vascular access. Compared with traditional surgical procedures, this method has the advantages of less bleeding, less trauma, fewer complications, faster postoperative recovery, and safety and reliability, which can greatly reduce the pain suffered by patients.

[0003] Although interventional therapy has become relatively mature, with several related products now available and widely implanted, in actual clinical practice, many arteriovenous stenoses occur at the junction of the main vessel and its branches, also known as bifurcations. Due to the presence of bifurcated vessels, after a stent is delivered to the lesion via a balloon dilatation catheter, it is difficult to avoid the distal end of the stent system being inserted into the branch. These narrow branches inevitably negatively impact the clinical operation of the stent system. Consequently, the presence of these branches presents numerous challenges for percutaneous angioplasty (PTA). One of these challenges is accurately positioning the stent within the bifurcation to improve the success rate of PTA. In recent years, several related research results have been published. However, as can be seen from the currently available prior art, these studies typically rely on adding new components / devices to the stent delivery system to improve stent positioning accuracy. However, these additional components often introduce new technical challenges, such as increasing the stent system's profile and making the operation more complicated, which in turn increases the risk of the procedure.

[0004] For example, patent application US20030055483A discloses a balloon catheter that incorporates a hollow hypotube and other components to provide rotational capabilities, thereby optimizing the positioning of the stent within a bifurcated vessel. However, this feature also increases the overall diameter of the stent system, complicating its structure and placing higher demands on the production process, production costs, and clinical implantability. Patent application WO2019156560A1 discloses a stent delivery system that includes an elastic sleeve wrapped around a portion of the inflatable balloon. Thus, the elastic sleeve can be configured to at least partially prevent or delay inflation of the inflatable balloon at the wrapped portion, compared to another portion of the inflatable balloon opposite the stent. By preventing premature inflation of the proximal portion of the balloon, the stent can be prevented from shifting during inflation. Furthermore, the combination of an anchor cable ensures the anchoring position relative to the bifurcation, thereby improving the positioning accuracy of the stent. However, this delivery system, with both the elastic sleeve and the anchor cable, suffers from disadvantages such as a complex structure, relatively high cost, a large overall diameter, and clinically difficult operation.

[0005] Therefore, it is very necessary to provide a stent delivery device suitable for the lesion area of ​​the bifurcation site, which has a simple structure, low cost, easy processing and production, simple clinical operation, small overall profile, low surgical risk and high positioning accuracy. Summary of the Invention

[0006] In view of this, the present invention provides a technical solution that can improve the positioning accuracy of the stent in the lesion area of ​​the bifurcation without adding new components / devices, but only by improving / optimizing the existing structure of the balloon or balloon dilatation catheter. This solution not only has a simple structure, low cost, and easy processing and production, but also has the advantages of convenient clinical operation, small overall profile, low surgical risk and high stent positioning accuracy.

[0007] In one aspect, the present invention provides a balloon comprising a balloon body and a distal body and a proximal body respectively connected to both ends of the balloon body. The interiors of the balloon body, the distal body, and the proximal body are combined to form an inner cavity, and the inner cavity is used to accommodate a medium for inflating the balloon. The distal body includes a first cone portion, and the proximal body includes a second cone portion. The magnitude of the cone angle α1 of at least the first cone portion and the magnitude of the diameter d of the balloon in the expanded state satisfy the relationship:

[0008] α1=k1lnd+b1; wherein: k1∈[11, 42.421], and b1∈[6.8, 31.8], 5≤d≤16, and d is a positive integer.

[0009] Furthermore, the balloon includes a balloon body and a distal body and a proximal body respectively connected to both ends of the balloon body. The interior of the balloon body, the distal body, and the proximal body are combined to form an inner cavity, and the inner cavity is used to accommodate a medium for inflating the balloon. The distal body includes a first cone portion, and the proximal body includes a second cone portion. At least the cone angle α1 of the first cone portion and the diameter d of the balloon body in the expanded state satisfy the relationship:

[0010] α1=k1lnd+b1; wherein: k1∈[11.009, 27.4], and b1∈[7.98, 14.2], 5≤d≤16, and d is a positive integer.

[0011] Furthermore, the cone angle α1 of the first cone portion and / or the cone angle α2 of the second cone portion and the diameter d of the balloon in the expanded state satisfy the relationship:

[0012] α1=k1lnd+b1; where: k1∈[12, 20], and b1∈[9, 25.8], 5≤d≤16, and d is a positive integer;

[0013] α2=k2lnd+b2; where: k2∈[12,20], and b2∈[9,25.8], 5≤d≤16, and d is a positive integer;

[0014] The roughness Ra of the capsule surface is 0.03 μm-0.2 μm, and the roughness Ra of the first cone surface is 0.05 μm-0.2 μm.

[0015] Furthermore, the length L1 of the first tapered portion and / or the length L2 of the second tapered portion satisfy the following relationship:

[0016] Where k∈[0.6, 2.1].

[0017] Furthermore, the length L1 of the first tapered portion and / or the length L2 of the second tapered portion satisfy the following relationship:

[0018] Where k∈[0.6, 2.1].

[0019] Furthermore, the first cone portion and / or the second cone portion includes at least one protrusion, and a distance D between at least a portion of the protrusion and the central axis of the balloon is 1.05-1.5 times the radius d / 2 of the balloon body.

[0020] Furthermore, the horizontal distance between at least part of the protrusion and the adjacent end on the capsule is less than 2 mm; the total length of the protrusion accounts for 5%-35% of the total length of the first cone or the second cone; the protrusion or its tangent forms a "V" shape with the capsule lying flat and the opening facing the capsule.

[0021] Furthermore, the included angle of the "V" shape is 30°-150°.

[0022] Furthermore, at least the first cone portion includes a stepped structure, the stepped structure includes at least a first cone segment, a second cone segment, and a straight segment, the straight segment is connected between the first cone segment and the second cone segment, and the other end of the first cone segment is connected to the capsule;

[0023] The cone angle α3 of the first cone section is 30°-150°, the cone angle α4 of the second cone section is 40°-178°, and the diameter of the straight section is smaller than the diameter of the capsule.

[0024] Furthermore, the cone angle α1 of the first cone portion and the cone angle α2 of the second cone portion and the diameter d of the balloon in the expanded state satisfy the relationship:

[0025] α1=k1lnd+b1; where: k1∈[11.51, 21.52], d∈[5, 9], b1∈[10.2, 21.4]; or k1∈[21, 27.87], d∈[10, 16], b1∈[-11.6, 3.85];

[0026] α2=k2lnd+b2; where: k2∈[11.51, 21.52], and d∈[5, 9], b2∈[10.2, 21.4]; or k2∈[21, 27.87], and d∈[10, 16], b2∈[-11.6, 3.85].

[0027] Furthermore, the ratio of the wall thickness of the capsule to the diameter of the capsule in the expanded state is 0.0015-0.010.

[0028] Another aspect of the present invention provides a balloon dilatation catheter, comprising:

[0029] The push tube includes a guidewire cavity for the guidewire to pass through and a filling cavity for the medium to pass through, wherein the guidewire cavity and the filling cavity are axially arranged in parallel and separated from each other by a partition;

[0030] A balloon, which is the balloon described in the present invention, is connected to one end of the push tube, and the inner lumen of the balloon is connected to the filling chamber;

[0031] a catheter seat connected to the other end of the push tube, the catheter seat comprising a first interface and a second interface, the first interface being in communication with the guidewire lumen, and the second interface being in communication with the filling lumen;

[0032] Wherein, the distal body also includes a distal joint, and the proximal body also includes a proximal joint. At least the proximal joint and the push tube are sealed to form a first connecting part, and the diameter of the first connecting part is less than or equal to the diameter of the proximal joint.

[0033] Furthermore, the inner diameter of the proximal joint is 1.78 mm-2.2 mm, the gap between the push tube and the proximal joint is no more than 0.2 mm, and the ratio of the wall thickness of the proximal joint to the wall thickness of the push tube is 0.2-2.0.

[0034] Furthermore, the ratio of the radial cross-sectional area of ​​the filling cavity to the radial cross-sectional area of ​​the pushing tube is 0.1-0.3, or the maximum width of the filling cavity along the radial direction of the pushing tube is 0.3mm-0.55mm.

[0035] Furthermore, the balloon dilatation catheter further comprises:

[0036] an inner tube, which is inserted into the inner cavity of the balloon, one end of the inner tube is connected to the push tube, and the other end of the inner tube is connected to the distal connector;

[0037] a developing ring, arranged on the inner tube;

[0038] Wherein, the guide wire cavity is communicated with the inner tube, and the diameter of the inner tube is smaller than the diameter of the push tube.

[0039] Furthermore, the distal connector is connected to the inner tube to form a second connecting portion, and the diameter of the second connecting portion is smaller than the diameter of the distal connector.

[0040] Furthermore, the balloon dilatation catheter further comprises:

[0041] a guide tube, arranged in front of the distal body along the pushing direction of the pushing tube and connected to the inner tube;

[0042] Wherein, the ratio of the diameter of the front end of the guide tube to the diameter of the front end of the second connecting part is 0.75-0.94.

[0043] Furthermore, the minimum wall thickness of the guidewire cavity is 0.08 mm to 0.12 mm; and / or the minimum wall thickness of the filling cavity is 0.08 mm to 0.15 mm.

[0044] The technical solution of the present invention further provides a stent system, comprising a stent and the balloon dilatation catheter as described in the present invention, wherein the stent is sleeved on the balloon of the balloon dilatation catheter.

[0045] Furthermore, the roughness Ra of the inner surface of the stent is 0.05 μm-0.4 μm; and the maximum static friction force on the surface of the balloon in the stent system is 2.8N-7.9N.

[0046] The present invention determines a certain intrinsic relationship between the balloon diameter d and the cone angle α1 in the expanded state and the positioning accuracy of the stent based on the clinical performance of the stent system when used in branch vessels, the size of the cone angle α1 of the first cone, the balloon diameter d in the expanded state, and the length L1 of the first cone and the volume of the cavity determined by the two, and combines the force characteristics of the fluid inside the balloon, such as direction and size, the balloon expansion method, and the friction coefficient of the blood vessel wall. Finally, a relationship is fitted, which determines the range of cone angles adapted to each balloon diameter. Within this range, a stent system formed by a balloon catheter with the above characteristics and loaded with a stent will neither move back during the expansion process due to an excessively small cone angle of the balloon cone, nor slip out of the stent during the expansion process due to an excessively large cone angle of the balloon cone, thereby making the entire stent system more clinically positioned. At the same time, the present invention also combines the performance of the balloon during the recovery and withdrawal process after the stent is released. Further, a more optimized cone angle range corresponding to each balloon specification is obtained. Within this range, the stent not only has a more precise positioning in the bifurcation lesion area, but also facilitates the recovery and withdrawal of the balloon, so that the balloon will not cause problems such as vascular damage during the withdrawal process, and will not even cause the final stent system to have a larger profile in the gripping state due to unreasonable balloon structure design, thereby increasing the difficulty of stent system delivery; in addition, the present invention further combines the structure and inner surface roughness of the stent itself, the surface roughness of the balloon, the structure of the balloon, and the mutual force between the balloon and the stent to further improve the positioning accuracy of the stent in the branch blood vessels; finally, the present invention further combines the balloon thickness and the setting and optimization of various parameters of the balloon catheter to ensure that the balloon not only has better positioning performance in the bifurcation lesion area while meeting the corresponding performance requirements, but also has a smaller profile, safe bursting pressure and pressure relief time, etc., thereby improving the overall performance of the balloon, which is beneficial to the delivery and safe implantation of the stent system. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0048] FIG1 is a cross-sectional schematic diagram of a first balloon provided by an embodiment of the present invention;

[0049] FIG2 is a cross-sectional schematic diagram of a second balloon provided by an embodiment of the present invention;

[0050] FIG3 is a cross-sectional schematic diagram of a third balloon provided by an embodiment of the present invention;

[0051] FIG4 is a cross-sectional schematic diagram of a fourth balloon provided by an embodiment of the present invention;

[0052] FIG5 is a cross-sectional schematic diagram of a balloon dilatation catheter provided in an embodiment of the present invention;

[0053] FIG6 is a partial enlarged schematic diagram of point A in FIG5 ;

[0054] FIG7 is a partial enlarged schematic diagram of point B in FIG5;

[0055] FIG8 is a schematic cross-sectional view of CC in FIG5 .

[0056] Description of the drawings:

[0057] 1. Balloon; 10. Lumen; d. Expanded diameter of balloon; W1. Wall thickness on one side of balloon; 12. Distal body; 120. First connecting portion; 121. First cone; 1211. First cone segment; 1212. Second cone segment; 1213. Straight segment; 122. Distal joint; L1. Length of first cone; D2. Diameter of distal joint; 13. Proximal body; 130. Second connecting portion; 131. Second cone; 132. Proximal joint; L2. Length of second cone; W3. Wall thickness of proximal joint; D3. Diameter of proximal joint; D. Distance between protrusion and balloon center axis; 14. Protrusion; 15. V-shape;

[0058] 2. Balloon dilatation catheter; 21. Push tube; 211. Guidewire lumen; W6, Guidewire lumen wall thickness; 212. Filling lumen; W4, Maximum width of the filling lumen; W7, Filling lumen wall thickness; 213. Separator; W5, Diaphragm thickness; 22. Catheter seat; 221, First interface; 222, Second interface; 23. Inner tube; 24. Development ring; 25. Guide tube. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0060] It should be noted that the terms "setting" and "connecting" should be understood in a broad sense. For example, it can be directly setting or connecting, or it can be indirectly setting or connecting through a central component or a central structure.

[0061] In addition, if there are terms such as "longitudinal", "transverse", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicating orientation or positional relationships in the embodiments of the present invention, they are based on the orientation or positional relationships shown in the drawings or the conventional placement state or usage state, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the structure, feature, device or element referred to must have a specific orientation or positional relationship, nor must it be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0062] The various specific technical features and embodiments described in the specific implementation methods can be combined in any suitable manner unless there is any contradiction. For example, different implementation methods can be formed by combining different specific technical features / embodiments. In order to avoid unnecessary repetition, the various possible combinations of the specific technical features / embodiments in the present invention will not be described separately.

[0063] In this article, the terms "proximal" and "distal" are relative positions from the perspective of a physician using the medical device. "Proximal" usually refers to the end of the medical device that is closest to the physician during normal operation, while "distal" usually refers to the end that first enters the patient's body.

[0064] As shown in FIG1 , an embodiment of the present invention provides a balloon 1 that has the ability to elastically expand or contract. Thus, when the balloon 1 is pushed to a target blood vessel where stenosis occurs, the expansion of the balloon 1 can expand the stent attached to the balloon 1, and the blood vessel is no longer stenotic due to the support of the stent, thereby restoring normal blood circulation in the target blood vessel.

[0065] As shown in Figure 1, in one embodiment, the balloon 1 includes a capsule body 11 and a distal body 12 and a proximal body 13 respectively connected to the two ends of the capsule body 11. The internal combination of the capsule body 11, the distal body 12 and the proximal body 13 forms an inner cavity 10, and the inner cavity 10 is used to accommodate the medium that expands the balloon 1. Specifically, the capsule body 11 is hollow and cylindrical with two ends open, and the distal body 12 and the proximal body 13 are respectively connected to the openings at the two ends of the capsule body 11. The distal body 12 and the proximal body 13 can be integrally formed with the capsule body 11, or they can be independent parts that are connected into one by welding. The capsule body 11, the distal body 12 and the proximal body 13 can undergo elastic deformation, so that they can increase in volume after expansion. The materials comprising the balloon body 11, distal body 12, and proximal body 13 can be materials that meet medical standards. For example, balloon body 11 can be made of nylon or a nylon composite material, polyurethane, or polyethylene, allowing balloon body 11 to expand to the required diameter under operating pressure. The distal body 12 and proximal body 13 can be made of the same material as balloon body 11, or other materials that meet medical standards and are preferably elastically deformable. After the distal body 12 and proximal body 13 are connected to the ends of balloon body 11, the resulting balloon 1 has a hollow interior, forming the inner lumen 10 of balloon 1. By introducing a medium meeting the pressure requirements, such as a gas or liquid, into the inner lumen 10, balloon body 11 can be elastically expanded, thereby achieving the purpose of expanding the attached stent. After the stent is expanded, the balloon can be removed / withdrawn from the blood vessel by depressurizing and deflation, followed by a retrieval / withdrawal procedure.

[0066] Specifically, during the operation of pushing the balloon 1 into the body, the distal body 12 is the end that first enters the body, and when the balloon 1 is withdrawn from the body after expansion is completed, the proximal body 13 is the end that first exits the body. Therefore, the distal body 12 is configured to include a first cone 121, and the proximal body 13 is configured to include a second cone 131. The diameters of the ends of the first cone 121 and the second cone 131 connected to the balloon body 11 are larger than the diameters of the ends away from the balloon body 11, forming cone angles of corresponding magnitudes, which provide a better guiding effect for the balloon. Thus, the first cone 121 and the second cone 131 both have a guiding function, so that during the process of pushing the balloon 1 into or withdrawing it from the body, the first cone 121 and the second cone 131 can respectively provide guidance for the corresponding movements, making the process of pushing the balloon into or withdrawing it from the body smoother.

[0067] In an embodiment of the present invention, as shown in FIG1 , when the diameter of the balloon 1 after expansion is constant, if the cone angle α1 is smaller, the length of the shoulder of the first cone portion 121 formed is longer, and the volume of the inner cavity formed by the first cone portion 121 is also larger; the larger the cone angle α1 is, the shorter the length of the shoulder of the first cone portion 121 formed is, and the volume of the inner cavity formed by the first cone portion 121 is also smaller. Since the first cone portion 121 is longer, when the stent system is delivered to the lesion area near the bifurcation, the depth and probability of the first cone portion 121 entering the branch vessel are greatly increased. As the fluid flows into the cavity formed by the first cone portion 121, the first cone portion 121 will exert a force on the vessel wall under the action of the fluid, and the vessel wall will also exert an opposite force on the first cone portion, thereby driving the entire stent system to move backward, resulting in an inaccurate positioning problem. Therefore, the present invention determines a certain intrinsic relationship between the size of the balloon diameter d and the cone angle α1 in the expanded state and the stent positioning accuracy based on the size of the cone angle α1 corresponding to the first cone 121, the balloon diameter d in the expanded state, the length L1 of the first cone 121 and the volume of the cavity determined by the two, and combines the force characteristics of the fluid inside the balloon such as direction and size, and the friction coefficient of the blood vessel wall. Based on this relationship, a reasonable interval is determined, and finally a relationship is fitted. Within the range determined by the relationship, the comprehensive force exerted on the balloon and its stent system by the branch blood vessels in the direction of the blood vessel is relatively small or even 0, thereby avoiding the overall backward movement of the stent system during the expansion process. The backward movement here refers to the movement of the entire stent system relatively away from the bifurcation of the blood vessel, that is, the entire stent system moves toward the proximal end of the balloon under the action of the bifurcation blood vessel. The technical solution of the present invention adopts the following relationship between the taper angle α1 of at least the first taper portion 121 and the diameter d of the balloon 1 in the expanded state: α1 = k1lnd + b1; where: k1∈[11, 42.421], b1∈[6.8, 31.8], 5≤d≤16, and d is a positive integer. Specifically, at least the taper angle α1 of the first taper portion 121 and the diameter d of the balloon 1 in the expanded state satisfy the above relationship.According to the fitted relationship, under the corresponding balloon expansion state and balloon diameter specification, there will be a suitable value range of the cone angle α1. Within this value range, there will be a good match between the balloon and the stent. When the stent system is applied to the lesion at the bifurcation of the blood vessel, the stent system will not be subjected to the force of the branch vessel in the direction of the blood vessel on the distal end of the stent system due to the cone angle of the balloon being too small or the shoulder being too long, which will be greater than the friction force in the opposite direction generated by the movement of the stent system relative to the blood vessel wall, thereby avoiding the entire stent from moving backward as the balloon expands, resulting in inaccurate stent positioning. In addition, within the range determined by the relationship, the cone angle of the balloon will not be too large or the length of the first cone 121 will not be too short, which will cause the stent to shift forward and backward or detach from the balloon as the balloon expands, thereby greatly improving the positioning accuracy of the stent in the area with branch vessel lesions, thereby greatly improving the success rate of PTA surgery. In summary, the present invention achieves the purposes of guided insertion, safe pushing, and accurate positioning of the stent in the target blood vessel by adopting a suitable cone angle design for the balloon 1. The design is ingenious and greatly improves the performance of the balloon 1.

[0068] Furthermore, in some embodiments, the present invention adopts a method in which the size of the cone angle α1 of at least the first cone portion 121 of the balloon and the size of the diameter d of the balloon body in the expanded state of the balloon 1 satisfy the following relationship: α1 = k1lnd + b1; wherein: k1∈[11.009, 27.4], and b1∈[7.98, 14.2], 5≤d≤16, and d is a positive integer. According to the above relationship, the balloon 1 not only satisfies the requirement of not causing the stent to shift or detach during expansion, but also avoids the problem that the balloon's retraction diameter is too large due to an excessively large cone angle, making it difficult to recover, thereby causing damage to the blood vessel or requiring the use of a larger sheath, and also avoids the problem that the stent is displaced forward and backward relative to the balloon or detached from the balloon due to an excessively large cone angle. Therefore, when the size of the cone angle α1 of the first cone 121 of the balloon and the size of the diameter d of the balloon body in the expanded state of the balloon 1 satisfy the above-mentioned relationship, it can not only ensure that the stent has more precise positioning, but also ensure that the balloon can be better recovered and withdrawn after the stent is expanded, so that the balloon causes as little damage as possible to the human blood vessels during the recovery and withdrawal process.

[0069] Furthermore, in some embodiments of the present invention, the cone angle α1 on the first cone 121 and / or the cone angle α2 on the second cone 131 and the diameter d of the balloon 1 in the expanded state satisfy the following relationship: α1 = k1lnd + b1; where k1∈[12, 20], b1∈[9, 25.8], 5≤d≤16, and d is a positive integer; α2 = k2lnd + b2; where k2∈[12, 20], b2∈[9, 25.8], 5≤d≤16, and d is a positive integer. That is, the cone angle α1 on the first cone 121 and the cone angle α2 on the second cone 131 both satisfy the above relationship, and the cone angles α1 and / or α2 are set to conform to the above value range. Thus, within the range of the balloon diameter and the corresponding first cone 121 and / or second cone 131 angles in the expanded state determined by the above relationship, not only can the problem of stent displacement or detachment, resulting from the first cone 121 and / or second cone 131 being too large or too small, and thus causing inaccurate positioning, be avoided. Furthermore, the size of the cone angles α1 and / or α2 within the above range can also make the balloon and the corresponding stent system easier to recover after expansion, thereby making them have a smaller profile in the compressed / recovered state, thereby facilitating the delivery and withdrawal of the balloon and its stent system in the body, and also causing less damage to human blood vessels during the delivery or withdrawal of the balloon and its stent system in the body. In the above technical solution of the present invention, the numerical values ​​of α1 and α2 can be the same or different, so that the lengths of the first cone 121 and the second cone 131 formed can be the same or different, and can be selected according to different application requirements, with good flexibility.

[0070] After the stent is delivered to the diseased area, as the balloon expands, the stent system will be subjected to the pressure of the blood vessels, the outward force of the fluid inside the balloon on the stent, and the friction in the opposite direction of the relative movement of the stent relative to the balloon. If the friction factor between the balloon and the stent is small, that is, the surface roughness of the balloon or the stent is small, then under the external combined force, the stent can easily slide relative to the balloon, making it impossible to accurately position the stent in the diseased area. If the roughness of the balloon cone is high, the static friction between the cone and the bifurcated blood vessel wall can be appropriately increased, thereby preventing the stent system from moving backward. Therefore, the present invention further combines the roughness of the balloon body and the cone surface to improve the positioning accuracy of the stent in the diseased area near the bifurcation.

[0071] In some embodiments, to improve the reliability of stent delivery, the surface roughness Ra of the capsule 11 is set to 0.03 μm-0.2 μm. Furthermore, the surface roughness Ra of the capsule 11 can be set to 0.05 μm-0.18 μm, and even further, the surface roughness Ra of the capsule 11 can be set to 0.08 μm-0.15 μm. The specific Ra value can be selected based on actual usage requirements. In this arrangement, since the stent is mainly pressed and gripped on the balloon body 11 for transportation, by setting the roughness Ra of the balloon body 11 surface within the above-mentioned range and coordinating it with the size of the cone angle of the balloon cone and the diameter d of the balloon body in the expanded state, when the stent system is pushed, there is a relatively appropriate maximum static friction force between the balloon and the stent, which can effectively prevent the stent from shifting or falling off on the balloon body 11 during transportation or expansion, so that the stent can be accurately delivered to the target blood vessel position to improve the success rate of the operation; and it also avoids the roughness of the balloon surface being too large, thereby increasing the difficulty and safety risks in the subsequent recovery and withdrawal process.

[0072] In some embodiments, the roughness Ra of the surface of the first cone 121 can also be set to 0.05μm-0.2μm. Furthermore, the roughness Ra of the surface of the first cone 121 can also be set to 0.1μm-0.2μm. Even further, the roughness Ra of the surface of the first cone 121 can also be set to 0.1μm-0.18μm. By setting the roughness of the balloon cone, especially the surface of the first cone 121, within the above range, the static friction between the branch vessel wall and the stent system can be effectively increased, thereby effectively preventing the stent from shifting forward or backward or detaching during the balloon expansion process, and avoiding the stent from shifting during the balloon withdrawal process due to excessive balloon surface roughness, thereby further improving the positioning accuracy of the stent.

[0073] In some embodiments, the length L1 of the first tapered portion 121 and / or the length L2 of the second tapered portion 131 satisfy the following relationship: Where k∈[0.6, 2.1], d is the diameter of the balloon in the expanded state, and k is the inner diameter of the distal end of the balloon. Referring to Figure 1 , "L1 length" refers to the total length of the hypotenuse of the first tapered portion 121 when the balloon 1 is inflated; "L2 length" refers to the total length of the hypotenuse of the second tapered portion 131 when the balloon 1 is inflated. The present invention sets the length of the balloon cone so that when the balloon 1 is expanded, the first cone 121 or the second cone 131 has sufficient deformation margin. The fluid is first rushed into the balloon cone and expands, and the middle part expands subsequently. Combined with the back pressure generated by the stent on the balloon body of the balloon 1 during the expansion process, as the stent system expands with the balloon, at least one portion that is higher than the outer surface of the balloon body 11 can be formed on the expanded first cone 121 or the second cone 131, thereby playing a limiting role. That is, the raised portion formed during expansion can limit the stent attached to the balloon body 11, and can avoid the problem of displacement or even detachment from the balloon body 11 caused by relative movement between the stent and the balloon 1 during the expansion process. The present invention can further achieve precise positioning of the stent by controlling the lengths of the balloon cones L1 and L2, combined with the appropriate cone angle of the balloon.

[0074] Furthermore, the length L1 of the first tapered portion 121 and / or the length L2 of the second tapered portion 131 satisfy the following relationship: Here, k∈[0.6, 2.1], where d is the diameter of the balloon in the expanded state, and k is the inner diameter of the distal end of the balloon. Thus, by setting the value range of L1 or L2 according to the above relationship, the length of the first tapered portion 121 or the second tapered portion 131 falls within a suitable setting range. Within this range, the tapered portion of the balloon forms a convex surface relative to the balloon during balloon expansion, thereby limiting the stent and preventing the stent from moving or detaching from the balloon during balloon expansion. Furthermore, the tapered lengths L1 and L2 are prevented from being excessively large, which would result in the tapered portion having an excessively large diameter in the gripping state and making delivery inconvenient or inconvenient for post-expansion recovery and withdrawal. Furthermore, excessively large tapered lengths L1 and L2 would also, to a certain extent, degrade the stent positioning accuracy. Therefore, by rationally designing the tapered length of the balloon, the present invention can improve the precise positioning of the stent without affecting the delivery of the stent system or the recovery and withdrawal of the balloon.

[0075] As shown in FIG2 , in some embodiments, the first tapered portion 121 and / or the second tapered portion 131 includes at least one protrusion 14, wherein at least a portion of the protrusion 14 has a distance D relative to the central axis of the balloon 1 that is 1.05-1.5 times the radius d / 2 of the balloon 1. That is, the protrusion 14 has at least a portion that is farthest from the central axis of the balloon, and the distance D between the farthest portion and the central axis of the balloon 1 is 1.05-1.5 times the radius d / 2 of the balloon 1. Further, at least a portion of the protrusion 14 has a distance D relative to the central axis of the balloon 1 that is 1.1-1.5 times the radius d / 2 of the balloon 1. Even further, at least a portion of the protrusion 14 has a distance D relative to the central axis of the balloon 1 that is 1.15-1.5 times the radius d / 2 of the balloon 1. With this arrangement, the highest part of the protrusion 14 formed after the balloon 1 is inflated is slightly higher than the outer surface of the balloon body 11, which can play a limiting role without hindering the transportation of the stent system in the blood vessel. As a result, the first cone 121 and / or the second cone 131 can have good smoothness and can be smoothly transported in the blood vessel. At the same time, the protrusion 14 can also be used to limit the stent attached to the balloon 1, thereby reducing the possibility of the stent shifting during the expansion of the balloon 1, thereby further improving the accuracy of the stent positioning.

[0076] It should be noted that, in the present invention, the "radius of the balloon" or "diameter of the balloon" refers to the radius or diameter of the balloon body in the expanded state.

[0077] In some embodiments, a plurality of protrusions 14 are provided on the first cone 121 and / or the second cone 131. Each protrusion 14 can be provided circumferentially around the first cone 121 and / or the second cone 131 near one end of the balloon body 11, and the protrusions 14 can be spaced apart or continuously distributed. When the protrusions 14 are continuously distributed, it can also be regarded as a circle of protrusions provided circumferentially around the first cone 121 and / or the second cone 131. In this way, the stent can be limited at various positions along the circumference by a plurality of protrusions 14, thereby improving the reliability of the stent limiting effect. The present invention can avoid the relative movement of the stent on the balloon surface. By combining the length of the balloon cone and the roughness of the respective surfaces of the balloon and the stent, the number of protrusions and the size or area of ​​the protrusions are adjusted to achieve a good limiting effect, thereby avoiding relative movement between the stent and the balloon.

[0078] Specifically, to improve the effectiveness of the protrusion 14 in retaining the stent, the horizontal distance between at least a portion of the protrusion 14 and the adjacent end of the capsule 11 can be set to less than 2 mm. The "adjacent end of the capsule" refers to the portion of the capsule 11 that is closest to the protrusion 14. Specifically, if the protrusion 14 is positioned on the first tapered portion 121, this refers to the portion of the capsule 11 that connects to the first tapered portion 121; if the protrusion 14 is positioned on the second tapered portion 131, this refers to the portion of the capsule 11 that connects to the second tapered portion 131. Because the stent is primarily attached to the capsule 11, this arrangement ensures that the protrusion 14 is positioned closer to the capsule 11. Thus, during expansion, the protrusion 14 can promptly retain the stent. This avoids the problem of the stent being partially displaced by the time the protrusion 14 contacts the stent due to an excessive distance between the protrusion 14 and the stent, which can lead to significant positioning errors. The present invention limits the position between the protrusion 14 and the capsule 11, so that the position between the protrusion 14 and the stent is maintained within an appropriate range, thereby improving the timeliness and effectiveness of the protrusion 11 limiting the stent.

[0079] In some embodiments, the total length of the protrusion 14 accounts for 5%-35% of the total length of the first tapered portion 121 or the second tapered portion 131. Furthermore, the total length of the protrusion 14 accounts for 10%-30% of the total length of the first tapered portion 121 or the second tapered portion 131. By setting the protrusion length in an appropriately proportioned manner, the present invention ensures that the protrusion 14 formed on the first tapered portion 121 or the second tapered portion 131 is neither too large to affect the smooth passage of the first tapered portion 121 or the second tapered portion 131 within the blood vessel, nor too small to affect the effectiveness of the stent retaining function. Furthermore, referring to FIG3 , the protrusion 14 or its tangent can also form a flat "V" shape 15 with the capsule 11, with the opening facing the capsule. Specifically, the "V" shape 15 can be formed between the protrusion 14 and the capsule 11; or the "V" shape 15 can be formed between the tangent of the protrusion 14 facing one side of the capsule 11 and the capsule 11. One side of the "V" shape 15 formed in these two ways is horizontally arranged, flush with or parallel to one side of the bladder 11, while the other side is angled upward or downward toward the bladder 11. Together, these two sides form a flat "V" shape 15 with its opening facing the bladder. This "V" shape 15 allows one end of the stent to be positioned within the structure of the "V" shape 15, thus defining the stent's position and preventing it from shifting or dislodging when the cone expands, providing reliable positioning.

[0080] Furthermore, the angle of the formed "V" shape 15 is 30°-150°. Exemplary angles include 30°, 40°, 45°, 52°, 60°, 65°, 70°, 80°, 100°, 120°, 130°, 140°, or 150°. Other values ​​between 30° and 150° are also possible. Setting the angle of the "V" shape 15 within this range not only allows for proper positioning of the stent, but also prevents the shape of the protrusion 14 from hindering the advancement of the tapered portion within the blood vessel.

[0081] As shown in FIG4 , in some embodiments, at least the first conical portion 121 is configured to include a stepped structure, which includes at least a first conical segment 1211, a second conical segment 1212, and a straight segment 1213. The straight segment 1213 is connected between the first conical segment 1211 and the second conical segment 1212. The other end of the first conical segment 1211 is connected to the capsule 11, and the other end of the second conical segment 1212 is connected to another object (such as a push tube or an inner tube). The taper angle α3 of the first conical segment 1211 is set between 30° and 150°, and the taper angle α4 of the second conical segment 1212 is set between 40° and 178°. The diameter of the straight segment 1213 is smaller than the diameter of the capsule 11. Specifically, the number of conical segments and straight segments in the stepped structure can be set according to actual design requirements. The stepped structure includes at least two conical segments and one straight segment, wherein the straight segment is used to connect two adjacent conical segments. For example, if a stepped structure has three conical segments, there are two straight segments, which are spaced in sequence, with two straight segments connected between adjacent segments. If a stepped structure has four conical segments, there are three straight segments, which are spaced in sequence, with three straight segments connected between adjacent segments, and so on. The diameter of the resulting stepped structure decreases in the direction of push. For example, in a stepped structure with two straight segments, the diameter of the straight segment closer to the capsule 11 is larger than the diameter of the straight segment farther from the capsule 11. With this arrangement, due to the small taper angle of the first cone section 1211, the stent is less likely to shift relative to the balloon surface. Furthermore, due to the small diameter of the straight section furthest from the balloon body 11, even if inserted into a branch vessel, the pressure of the branch vessel on the first cone section will not easily cause the stent system to shift backwards as a whole. Thus, when the balloon 1 expands, the first cone section 121 is prevented from being squeezed by the branch vessel, causing the balloon 1 and the stent system to move proximally as a whole, thereby improving the accuracy of the stent's positioning in the target vessel. Furthermore, this design can also reduce the profile of the front end of the first cone section 121 after expansion, making its expanded diameter significantly smaller than the diameter of the branch vessel. This effectively prevents the stent system from shifting backwards significantly due to squeezing by the branch vessel during expansion, thereby improving the accuracy of the stent's positioning.

[0082] Furthermore, in one embodiment, when the roughness Ra of the surface of the first cone 121 is set to 0.05μm-0.2μm, it may refer to the roughness of the surface of the entire stepped structure, or it may refer to the roughness of the surface of the portion of the stepped structure inserted into the branch blood vessel, so as to increase the friction between the branch blood vessel and the balloon 1. When the first cone 121 has a portion in contact with the branch blood vessel, the friction coefficient between the portion in contact with the branch blood vessel is large, so that the stent system will not shift backward as a whole under the drive of the first cone 121, and will not push the balloon 1 and the stent to move backward as a whole, and the stent will not shift, so that the stent can be accurately positioned at the target blood vessel. Specifically, the roughness Ra of the surface of the first cone 121 can be any value in the above-mentioned value range, such as 0.05μm, 0.08μm, 0.10μm, 0.12μm, 0.15μm, 0.18μm or 0.20μm, etc., so as to meet the premise of not affecting the smooth pushing in the blood vessel and increasing the friction between the branch blood vessels.

[0083] As shown in Figure 4, when the stepped structure is set to have two cone sections and one straight section, the extension line of the second cone section 1212 intersects with the central axis of the balloon 1 to form an intersection E, and the opposite sides of the capsule body 11 are respectively connected to the intersection E, and the angle between the two connections is defined as the cone angle α1 of the first cone portion 121.

[0084] In another embodiment, when the first cone 121 is configured to include the above-mentioned first cone section 1211, the second cone section 1212 and the straight section 1213, and the protrusion 14 is also provided, the protrusion 14 can be set on the first cone section 1211 so that the position of the protrusion 14 is closer to the balloon body 11, so that when the balloon 1 expands, the protrusion 14 can effectively limit the position of the stent, prevent the stent from shifting or falling off, and improve the accuracy of the stent positioning.

[0085] In some embodiments, the size of the cone angle α1 on the first cone 121 and / or the cone angle α2 of the second cone 131 and the size of the diameter d of the balloon in the expanded state satisfy the following relationship: α1 = k1lnd+b1; wherein: k1∈[11.51, 21.52], and d∈[5, 9], b1∈[10.2, 21.4]; or k1∈[21, 27.87], and d∈[10, 16], b1∈[-11.6, 3.85]; α2 = k2lnd+b2; wherein: k2∈[11.51, 21.52], and d∈[5, 9], b2∈[10.2, 21.4]; or k2∈[21, 27.87], and d∈[10, 16], b2∈[-11.6, 3.85]. In this way, balloons 1 of different specifications correspond to different cone angle ranges. Within the corresponding cone angle range, the stent used in combination can be accurately positioned in the lesion area without deviation, and the size of the cone formed can still meet the requirements of smooth pushing of the balloon 1 in the blood vessel.

[0086] Specifically, the greater the ratio of the wall thickness W1 of the balloon 11 to the diameter d of the balloon 11 in its expanded state, the higher the bursting pressure of the balloon 1; conversely, the smaller the ratio of the wall thickness W1 of the balloon 11 to the diameter d of the balloon 11 in its expanded state, the lower the bursting pressure of the balloon 1. In an embodiment of the present invention, as shown in FIG1 , the ratio of the wall thickness W1 of the balloon 11 to the diameter d of the balloon 11 in its expanded state is set to 0.0015-0.010. For example, if the diameter d of the balloon 1 is 5 mm, the single-side wall thickness W1 of the balloon 11 is 0.0075 mm-0.05 mm, or if the diameter d of the balloon 1 is 10 mm, the single-side wall thickness W1 of the balloon 11 is 0.015 mm-0.1 mm. This arrangement maintains the relationship between the wall thickness of the balloon 11 and the expanded diameter of the balloon 1 within a suitable range, ensuring that the balloon 1 exhibits an appropriate burst pressure and meets the required diameter, preventing bursting before reaching the desired diameter. With this designed ratio of wall thickness W1 to diameter d, the balloon 1 can reliably expand the stent to its rated diameter while maintaining a compact profile, further facilitating intravascular delivery.

[0087] The diameter d of the balloon 1 in the expanded state mainly refers to the maximum diameter that the balloon 11 can expand to. For example, if the diameter of the balloon 1 in the expanded state is 5 mm, the maximum diameter that the balloon 11 can expand to is 5 mm.

[0088] In some embodiments, the burst pressure of balloon 1 is adjusted based on the diameter of balloon 1 . Balloons 1 of different diameters may have the same or different burst pressures. In this embodiment, the diameter of balloon 1 ranges from 5 mm to 16 mm, and the burst pressure of balloon body 11 ranges from 10 to 30 atm (atm is a common unit of atmospheric pressure, with 1 standard atmosphere being denoted as 1 atm).

[0089] As shown in FIG1 , in some embodiments, the cone angle α1 of the first cone portion 121 and the cone angle α2 of the second cone portion 131 are equal or unequal in value. When the cone angle α1 of the first cone portion 121 and the cone angle α2 of the second cone portion 131 are equal in value, the cone angles at both ends of the balloon 1 are equal, which facilitates production. Moreover, when connecting the balloon 1 to other objects (such as a push tube), there is no need to distinguish the positions of the two ends, which facilitates welding. When the cone angle α1 of the first cone portion 121 and the cone angle α2 of the second cone portion 131 are unequal in value, the angle value of the cone angle α2 of the second cone portion 131 can be set to be smaller than the angle value of the cone angle α1 of the first cone portion 121, such as the cone angle α1 of the first cone portion 121 is 50°, 60°, 65°, or 75°, while the cone angle α1 of the second cone 131 is 28°, 34°, 40°, or 45°. In this way, the head of the proximal body 13 is smaller, which provides a good guiding effect when the balloon 1 is withdrawn from the body, facilitating the withdrawal of the balloon 1. Of course, the cone angle α2 of the second cone 131 can also be set to be greater than the cone angle α1 of the first cone 121. In this case, the head of the second cone 131 in the contracted state is larger, which can help position the stent when it is attached to the balloon 1 to prevent the stent from shifting.

[0090] As shown in Figures 5 to 8, the present invention also provides a balloon dilatation catheter 2, including a push tube 21, a balloon and a catheter seat 22. The push tube 21 includes a guidewire cavity 211 for the guidewire to pass through and a filling cavity 212 for the medium to pass through. The guidewire cavity 211 and the filling cavity 212 are axially arranged in parallel and isolated from each other by a partition 213. The balloon is the balloon 1 mentioned above, and the balloon 1 is connected to one end of the push tube 21, and the inner cavity 10 of the balloon 1 (refer to Figure 1) is connected to the filling cavity 212; the catheter seat 22 is connected to the other end of the push tube 21, and the catheter seat 22 includes a first interface 221 and a second interface 222, the first interface 221 is connected to the guidewire cavity 211, and the second interface 222 is connected to the filling cavity 212. Specifically, there are at least two mutually isolated and non-connected cavities in the push tube 21, usually including at least a guidewire cavity 211 and a filling cavity 212. Since the push tube 21 is made of a relatively soft material, when pushing the balloon 1 into the body, it is necessary to insert a guide wire into the guide wire cavity 211. The guide wire is usually made of a metal material with relatively good hardness to increase the relative hardness of the push tube 21, so that the balloon 1 can pass smoothly in the blood vessel. The filling cavity 212 is used to pass a medium such as gas or liquid into the inner cavity 10 of the balloon 1 through the filling cavity 212 after the balloon 1 is pushed to the corresponding position, so as to expand the balloon 1. The setting of the catheter seat 22 is used for holding during operation to facilitate the application of force for the corresponding surgical operation. The catheter seat 22 is correspondingly provided with a first interface 221 connected to the guide wire cavity 211 and a second interface 222 connected to the filling cavity 212. The openings of the first interface 221 and the second interface 222 are relatively large, which facilitates the insertion of a guide wire from the first interface 221 to enter the guide wire cavity 211 and the introduction of a medium from the second interface 222 to expand the balloon 1.

[0091] Specifically, since the balloon 1 (see FIG1 ) needs to be sealed and connected to the outer surface of the push tube 21, one end of the balloon 1 for connection is usually sleeved on the push tube 21 for welding. In an embodiment of the present invention, as shown in FIG5 to FIG7 , the distal body 12 is further configured to include a distal connector 122, and the proximal body 13 is further configured to include a proximal connector 132. Moreover, at least a first connecting portion 130 is formed to seal the connection between the proximal connector 132 and the push tube 21. In this way, the proximal connector 132 is a hollow structure, and the proximal connector 132 is sleeved on the push tube 21. Then, a method such as laser welding is used to seal the proximal connector 132 and the push tube 21, and a first connecting portion 130 is formed at the connection between the two. The purpose of effective sealing connection is achieved through the formed first connecting portion 130. At the same time, the filling chamber 212 in the push tube 21 needs to be in communication with the inner cavity 10 of the balloon 1 so that a medium can be introduced into or withdrawn from the inner cavity 10 of the balloon 1 through the filling chamber 212 to achieve expansion or contraction of the balloon 1. In an embodiment of the present invention, a first connecting portion 130 is formed between the proximal connector 132 and the push tube 21 by laser welding. The first connecting portion 130 is continuously distributed circumferentially around the outer surface of the push tube 21, providing a reliable sealed connection. Moreover, the diameter of the formed first connecting portion 130 at its highest point is less than or equal to the diameter D3 of the proximal connector 132. That is, the first connecting portion 130 does not additionally increase the diameter of the proximal connector 132, and thus does not become an obstacle during intravascular delivery, providing good passability and facilitating intravascular delivery.

[0092] In other embodiments, the balloon 1 and the push tube 21 may be connected by inserting one end of the push tube 21 through the proximal connector 132, then passing through the inner lumen 10 of the balloon 1, and exiting through the distal connector 122. The proximal connector 132 and the distal connector 122 are sealed at their respective connections to the push tube 21, such as by laser welding, to connect the filling lumen 212 of the push tube 21 to the inner lumen 10 of the balloon 1. The resulting balloon dilation catheter can also be used in situations where the diameter of the blood vessel is larger and the distal body 12 can be inserted.

[0093] The balloon dilatation catheter 2 provided in the embodiment of the present invention uses the balloon 1 of the above structure. Since the first cone 121 of the balloon 1 is of appropriate length, the balloon dilatation catheter 2 is used to implant a stent into a narrow target blood vessel. During the balloon dilatation process, the stent will not be displaced or detached, and the stent can be accurately positioned at the target blood vessel, thereby improving the effectiveness and safety of the operation. At the same time, the balloon dilatation catheter 2 provided in the embodiment of the present invention is suitable for the delivery and expansion of any type of stent, including degradable stents and non-degradable stents. The material types of the stent include but are not limited to iron-based, magnesium-based, zinc-based, polylactic acid, cobalt-chromium alloy, nickel-titanium alloy and the like. That is, the balloon dilatation catheter 2 can be applied in a wide range of applications and has good market prospects.

[0094] In an embodiment of the present invention, since the balloon 1 needs to be of different sizes after expansion, such as a diameter of 5 mm, 8 mm, or 14 mm, the proximal connector 132 on balloons of different sizes also varies in size. To ensure a reliable sealed connection between the balloon 1 and the push tube 21, the inner diameter of the proximal connector 132 is set to 1.78 mm-2.2 mm, and the gap between the push tube 21 and the proximal connector 132 is no greater than 0.2 mm. Specifically, the gap between the proximal connector 132 and the push tube 21 needs to be maintained within an appropriate range. A gap that is too large will not facilitate welding between the two, and may easily result in poor welding (such as holes due to welding), resulting in an unsealed connection. A gap that is too small will easily make it difficult for the push tube 21 to be inserted into the proximal connector 132, and may easily cause damage to the connection. Therefore, according to the gap requirements between the push tube 21 and the proximal connector 132, selecting a proximal connector 132 with an appropriate inner diameter size will help improve the effectiveness of the connection between the push tube 21 and the proximal connector 132.

[0095] As shown in Figures 1 and 6, in an embodiment of the present invention, the ratio of the wall thickness W3 of the proximal joint 132 to the wall thickness of the push tube 21 is 0.2-2.0. In other embodiments, the ratio of the wall thickness W3 of the proximal joint 132 to the wall thickness of the push tube 21 is 0.6-2.0. Specifically, since a guide wire cavity 211 and a filling cavity 212 are formed in the push tube 21, and during welding, the proximal joint 132 will be connected to the side wall of the guide wire cavity 211 and the side wall of the filling cavity 212 at the same time. Therefore, the wall thickness of the push tube 21 mentioned here refers to the smallest wall thickness value in the guide wire cavity 211 or the filling cavity 212. Both the proximal joint 132 and the push tube 21 need to have a certain wall thickness to ensure reliable welding. If the wall thickness of the proximal connector 132 or the push tube 21 is too thin, weld cracking is likely to occur. If the wall thickness of the proximal connector 132 or the push tube 21 is too thick, a bulge may form on the first connecting portion 130, causing the diameter of the first connecting portion 130 to be excessively large, thus affecting smooth pushing. Therefore, setting the ratio of the wall thickness W3 of the proximal connector 132 to the wall thickness of the push tube 21 within the aforementioned range ensures reliable welding and good sealing between the two without increasing the diameter of the first connecting portion 130 or the additional diameter of the proximal connector 132. For example, the balloon 1 has specifications of different diameters, but the diameter of the push tube 21 connected to the balloon 1 remains consistent. For example, when welding a push tube 21 with a wall thickness of 0.08 mm, when the diameter of the balloon 1 is 5 mm, the corresponding wall thickness W3 of the proximal joint 132 is 0.05 mm, and when the diameter of the balloon 1 is 16 mm, the corresponding wall thickness W3 of the proximal joint 132 is 0.4 mm.

[0096] As shown in Figures 5 and 6, in an embodiment of the present invention, in order to improve the smoothness of the guidewire passing into the guidewire cavity 211 and pushing it, the position of the first interface 221 set on the catheter seat 22 is kept flush with the position of the guidewire cavity 211. Furthermore, the axis of the first interface 221 is made colinear with the axis of the guidewire cavity 211, so that the guidewire can smoothly pass through the first interface 221 and extend into the guidewire cavity 211, and can be smoothly pulled and slid in the guidewire cavity 211 without getting stuck, thereby improving the operability of the operation.

[0097] As shown in Figures 5 to 7, in one embodiment, the balloon dilatation catheter 2 further includes an inner tube 23 and a developing ring 24. The inner tube 23 has a single lumen structure, and its diameter is smaller than that of the push tube 21. Specifically, to allow a guidewire to be inserted into the distal body 12 and enhance the passability of the distal body 12 within the blood vessel, the inner tube 23 is provided. The inner tube 23 is passed through the inner lumen 10 of the balloon 1, with one end of the inner tube 23 connected to the push tube 21 and the other end connected to the distal connector 122. This allows the guidewire to pass through the inner tube 23 without disrupting the sealing of the inner lumen 10 of the balloon 1. Furthermore, the diameter of the inner tube 23 is smaller than that of the push tube 21. Therefore, the smaller diameter of the inner tube 23 does not cause the overall dimensions of the balloon to be excessively large when compressed, thereby minimizing the overall dimensions of the balloon 1 when uninflated, thereby facilitating smooth passage within the blood vessel.

[0098] Specifically, developing rings 24 are disposed on inner tube 23, and at least two developing rings 24 are typically provided. The developing rings 24 are spaced apart at predetermined intervals on inner tube 23 to display the position of balloon 1 within the body during surgery, enabling accurate positioning of balloon 1. The specific structure and material of the developing rings 24 are conventional designs and are not described here in detail.

[0099] As shown in Figures 1, 5, and 7, in an embodiment of the present invention, the distal connector 122 is connected to the inner tube 23 to form a second connecting portion 120. The diameter of the second connecting portion 120 is smaller than the diameter D2 of the distal connector 122. Specifically, the distal connector 122 is sleeved onto the inner tube 23 and a sealed connection is achieved between the distal connector 122 and the inner tube 23 by laser welding or other means, thereby ensuring the sealing of the inner lumen 10 of the balloon 1. The sealed connection between the distal connector 122 and the inner tube 23 forms the second connecting portion 120. The diameter of the second connecting portion 120 is smaller than the diameter D2 of the distal connector 122. Furthermore, the diameter D2 of the distal connector 122 itself is relatively small. Therefore, the second connecting portion 120 does not increase the diameter D2 of the distal connector 122. Therefore, when inserted into the body, the smaller diameter of the second connecting portion 120 is more convenient for insertion and intravascular delivery. Specifically, the diameter of the second connecting portion 120 is 1.25 mm to 1.47 mm, and the diameter D2 of the distal connector 122 is 1.54 mm to 2.4 mm. The wall thickness of the distal connector 122 is generally the same as that of the proximal connector 132, thereby reducing the difficulty of production and processing.

[0100] Specifically, when expanding a compressed stent by inflating the balloon 1, a certain amount of time is typically required to stabilize the expansion effect after inflation. However, if the inflated balloon 1 remains in close contact with the vessel wall, blood flow within the vessel can be blocked. Prolonged blood flow blockage can lead to additional risks such as myocardial ischemia or myocardial infarction. Therefore, in an embodiment of the present invention, the ratio of the radial cross-sectional area of ​​the filling lumen 212 to the radial cross-sectional area of ​​the push tube 21 is set to 0.1-0.3. This provides a larger radial cross-sectional area per unit area, thereby increasing the flow rate of medium that can pass through the filling lumen 212 per unit time. This reduces both the time required to inflate the balloon 1 to its rated diameter and the time required to withdraw the medium from the balloon 1. This shortens the time blood flow within the vessel is blocked, improving surgical safety. Alternatively, the duration of stable expansion after inflation is ensured, thereby enhancing the stability of the stent expansion effect. In the embodiment of the present invention, according to the design requirements, the radial cross-sectional area of ​​the filling cavity 212 is 50 mm 2 -55mm 2 The radial cross-sectional area of ​​the push tube 21 is 245 mm 2 -250mm 2 In one embodiment, the radial cross-sectional area of ​​the filling chamber 212 is 53 mm. 2 The radial cross-sectional area of ​​the push tube 21 is 248 mm. 2 .

[0101] The above-mentioned "radial cross-sectional area of ​​the filling chamber 212" refers to the shape of the filling chamber 212 obtained along the axial direction perpendicular to the push tube 21, and the area of ​​the filling chamber 212 under this shape; the above-mentioned "radial cross-sectional area of ​​the push tube 21" refers to the cross-sectional shape obtained along the axial direction perpendicular to the push tube 21, and the area of ​​the entire cross-sectional shape.

[0102] As shown in Figures 6 and 8 , in an embodiment of the present invention, the maximum width W4 of the filling lumen 212 along the radial direction of the push tube 21 is set to 0.3 mm to 0.55 mm. Specifically, given a given area of ​​the filling lumen 212, increasing the radial dimension of the filling lumen 212 will result in an increase in the diameter of the entire push tube 21. Therefore, to reduce the diameter of the push tube 21 and maximize the area of ​​the filling lumen 212, the maximum radial width W4 of the filling lumen 212 is set between 0.3 mm and 0.55 mm. This maximizes the area of ​​the filling lumen 212 while still meeting the required strength. Furthermore, by configuring the filling lumen 212 in a "crescent" shape as shown in Figure 8 , the area between the filling lumen 212 and the guidewire lumen 211 becomes part of the filling lumen 212, fully utilizing the interior area of ​​the push tube 21 and increasing the area of ​​the filling lumen 212. This, in turn, increases the inflation rate of the balloon 1 and reduces the time required for decompression.

[0103] As shown in Figures 5 and 7, in an embodiment of the present invention, the balloon dilatation catheter 2 also includes a guide tube 25. The guide tube 25 is arranged in front of the distal body 12 along the pushing direction of the pushing tube 21 and is connected to the inner tube 23. The guide tube 25 is made of a flexible material and is soft and bendable as a whole. The guide tube 25 is arranged at the front end in the pushing direction. Therefore, it can not only play a guiding role, but also its good flexibility will not damage the blood vessels. Generally, the radial cross-section of the guide tube 25 is circular. In order to make the guide tube 25 have better guiding properties, the ratio of the diameter of the front end of the guide tube 25 to the diameter of the front end of the second connecting part 120 is set to 0.75-0.94. The diameter of the front end of the guide tube 25 refers to the diameter at the front end of the guide tube 25, and the diameter of the front end of the second connecting part 120 refers to the diameter at the front end of the second connecting part 120 in the direction toward the guide tube 25. In this way, along the pushing direction, the diameter of the front end of the guide tube 25 is the smallest and is no larger than the diameter at the front end of the second connecting part 120. Therefore, toward the pushing direction, the overall shape of the guide tube 25 gradually shrinks, which is conducive to guiding during pushing.

[0104] As shown in Figures 5 to 8, in some embodiments, the partition 213 used to separate the guidewire cavity 211 and the filling cavity 212 is set as a diaphragm, and the thickness W5 of the diaphragm is set to 0.10mm-0.14mm. The material of the diaphragm is the same as that of the push tube 21, and is formed simultaneously when forming the guidewire cavity 211 and the filling cavity 212. In an embodiment of the present invention, the thickness W5 of the diaphragm is set between 0.10mm and 0.14mm, such as 0.1mm or 0.12mm or 0.134mm or 0.14mm. The diaphragm within this thickness range has a strength that not only satisfies the requirement of not being punctured when the guidewire is inserted, but also does not rupture when a medium with a certain pressure is input into the filling cavity 212. At the same time, the diaphragm within this thickness range will not cause the area of ​​the guidewire cavity 211 or the filling cavity 212 to be reduced.

[0105] As shown in Figure 8, in some embodiments, the minimum wall thickness W6 of the guidewire lumen 211 is 0.08mm-0.12mm, and / or the minimum wall thickness W7 of the filling cavity 212 is 0.08mm-0.15mm.As in some embodiments, the minimum wall thickness W6 of the guidewire lumen 211 is 0.08mm, and the minimum wall thickness W7 of the filling cavity 212 is 0.11mm, or in other embodiments, the minimum wall thickness W6 of the guidewire lumen 211 is 0.11mm, and the minimum wall thickness W7 of the filling cavity 212 is 0.13mm.Certainly, in other embodiments, the minimum wall thickness W6 of the guidewire lumen 211 can also be other arbitrary values ​​between 0.08mm-0.12mm, and the minimum wall thickness W7 of the filling cavity 212 can also be other arbitrary values ​​between 0.08mm-0.15mm. In this way, the wall thickness of the guidewire cavity 211 and the filling cavity 212 are respectively set within this range. On the premise of ensuring the strength requirements for use, the filling cavity 212 and the guidewire cavity 211 can also have a sufficiently large cross-sectional area as much as possible to meet the requirements of smoothly pushing the guidewire and improving the efficiency of inflating or depressurizing the balloon 1.

[0106] An embodiment of the present invention also provides a stent system comprising a stent and the aforementioned balloon dilatation catheter 2, wherein the stent is mounted on the balloon 1 of the balloon dilatation catheter 2. Stents include degradable and non-degradable stents, and stent materials include, but are not limited to, iron-based, magnesium-based, zinc-based, polylactic acid, cobalt-chromium alloy, nickel-titanium alloy, and the like. The balloon dilatation catheter 2 is used to deliver the stent to a target vessel to thereby dilate the stenotic target vessel. Specifically, the stent is pre-pressed against the contracted balloon 1 in an undeployed state. The end of the balloon dilatation catheter 2, which includes the balloon 1, is inserted into the vessel and pushed to the target vessel. The stent is then expanded by inflating the balloon 1, thereby dilating the target vessel with the support provided by the stent. The balloon dilatation catheter 2 can accurately deliver the stent to the target vessel, and when the balloon 1 is expanded, the stent does not shift or fall off the balloon 1, allowing the stent to be precisely positioned in the target vessel, thereby improving the effectiveness of the stent system for stent implantation surgery.

[0107] Specifically, the roughness Ra of the stent inner surface is 0.05 μm to 0.4 μm, and the maximum static friction force on the balloon surface in the stent system is 2.8 N to 7.9 N. Here, the roughness of the stent inner surface refers to the roughness of the inner and / or outer surfaces of the stent, and the maximum static friction force on the balloon surface in the stent system refers to the maximum static friction force on the balloon surface in the final expanded state of the stent system.

[0108] This arrangement ensures that the stent surface finish is within an appropriate range, preventing scratches or punctures on the balloon 1 due to excessively high stent inner surface roughness, damage to the inner wall of the blood vessel due to excessively high stent outer surface roughness, and relative slippage between the stent and balloon 1 or between the stent and the blood vessel wall during expansion due to excessively low stent inner surface roughness. In other words, the present invention further improves the accuracy of stent positioning within a lesion near a blood vessel bifurcation by controlling the roughness of the stent's inner and outer surfaces. Furthermore, the maximum static friction force between the stent and the surface of the balloon 1 in the stent system is set between 2.8N and 7.9N. Therefore, the stent system has suitable anti-slip properties while being able to move smoothly in the blood vessel, so that the stent can be reliably attached to the balloon 1 after being squeezed and not loosened. Therefore, when pushing, there will be no relative movement between the stent and the balloon 1, and the stent will not shift or fall off on the balloon 1, ensuring that the stent can be accurately pushed to the target blood vessel. Moreover, when the stent system is expanded by the balloon, there will be no relative sliding between the stent and the balloon due to the force of the branch blood vessels, thereby avoiding additional surgical risks caused by stent displacement or falling off, and improving the safety of the operation.

[0109] The balloon and balloon dilatation catheter used in the present invention can be used to create a stent system. After the stent is delivered to the target bifurcation lesion, the balloon can be expanded from the proximal end to the balloon body and then to the distal end, or from the distal end to the balloon body and then to the proximal end. Furthermore, the present invention preferably expands the balloon body first, followed by the proximal and distal ends. This method can improve the positioning accuracy of the stent.

[0110] It should be noted that the "length of the shoulder of the first cone portion 121" in the present invention refers to the length of the shortest line segment formed by the two farthest endpoints of the first cone portion 121; the "length of the first cone portion 121" in the present invention refers to the actual length of the cone portion. Since the cone portion may be uneven or have arc segments, etc., the length of the first cone portion 121 in the present invention should actually be greater than or equal to the length of the shoulder of the first cone portion 121.

[0111] In the present invention, the stent positioning accuracy is measured by the deviation between the final position of the stent after implantation in the vascular lesion area and the target position before implantation. For example, if the target position of the stent before implantation corresponds to the segment corresponding to points a and b of the lesion vessel, and the stent is actually placed in the lesion vessel segment located by points a' and b', then the deviation between the stent's position after implantation and the position before implantation is the distance d between points a and a'. 偏离 . General bracket |d 偏离 The smaller the size, the higher the positioning accuracy of the bracket. 偏离 >0 means the stent has shifted distally, d 偏离 <0 means that the stent has shifted toward the proximal end. 偏离 | is used to measure the accuracy of the stent positioning. Generally, the stent is displaced within ±3mm, that is, |d 偏离 |≤3 can meet the demand for bracket positioning accuracy to a certain extent.

[0112] As used herein, the "maximum static friction" on the balloon surface of a stent system refers to the maximum friction experienced by the stent before relative motion between the stent and the balloon occurs, specifically the friction experienced when the stent is in a critical state, about to initiate relative motion. This maximum static friction is closely related not only to the roughness of the stent's inner surface and the roughness of the balloon's outer surface, but also to factors such as the stent's structure, weight, the crimping method used for the stent system, the balloon's expansion method, and the shoulder or cone length of the balloon's cone.

[0113] The "retraction diameter ratio" as used herein refers to the ratio of the balloon's diameter after stent deployment and retraction to its diameter in the folded state before the stent is applied. A smaller ratio indicates better balloon retraction and easier retraction, while a smaller ratio indicates the opposite. The balloon's diameter after stent deployment and retraction in this invention is also referred to as the retraction diameter, which is the distance between the two farthest points on the balloon's cross-section after retraction.

[0114] DETAILED DESCRIPTION

[0115] In order to facilitate the understanding of the present invention, the design points of the present invention are described below in conjunction with some specific embodiments. It can be understood that the relevant embodiments are only some examples of the scheme of the present invention and do not constitute a limitation on the scope of application. That is, what is described below are only some preferred embodiments of the present invention. The protection of the present invention is not limited to the following preferred embodiments. For example, for the sake of ease of understanding, the embodiments of the present invention are all described using balloon dilatation catheters with the following structure, but it does not mean that the technical solution of the present invention is only applicable to balloon dilatation catheters with the following structure. It should be pointed out that for those skilled in the art, several variations and improvements made on the basis of this invention concept all fall within the scope of protection of the present invention. The parts used without indicating the manufacturer are all conventional products that can be purchased commercially. The basic structure of the balloon catheter used in the embodiments of the present invention is as follows:

[0116] The balloon dilatation catheter of the present invention includes a push tube, a balloon, a catheter seat, an inner tube, a developing ring, and a guide tube. The balloon includes a balloon body, a distal body, and a proximal body connected to both ends of the balloon body, respectively. The distal body includes a first tapered portion, and the proximal body includes a second tapered portion. The push tube includes a guidewire lumen and a filling lumen. The proximal body is sheathed and connected to one end of the push tube. The filling lumen communicates with the inner lumen of the balloon, and the catheter seat is connected to the other end of the push tube. The inner tube is inserted into the inner lumen of the balloon, one end of the inner tube is connected to the push tube, and the distal body is sheathed and connected to the other end of the inner tube. The guide tube is arranged in front of the distal body and connected to the inner tube. If the balloon has a developing ring, it is mainly arranged on the inner tube.

[0117] Test method:

[0118] 1. Roughness Ra

[0119] The average roughness Ra defines the average distance from the measuring point on the surface to the average center line of the measured object. The center line intersects the actual contour within the reference distance so that the sum of the contour deviations (relative to the center line) becomes minimum. Therefore, the average roughness Ra corresponds to the arithmetic mean of the deviations from the center line. The present invention measures the roughness of the surface of the stent or balloon with the help of an optical measuring device and with reference to the ISO25178 standard. For example, with the help of Keyence's optical microscope VHX100, which has software-supported 3D surface analysis and a resolution of 54M pixels, and is combined with a Zeiss optical magnification lens with a maximum magnification of 2500×. The software allows a virtual section through the surface and calculates the average roughness depth of the measurement area.

[0120] 2. Maximum static friction

[0121] The present invention uses the following method to measure the maximum static friction force on the balloon surface of the stent system in the expanded state:

[0122] First, simulate use was performed in a curved anatomical model in a 37±2°C water bath environment, and the stent was marked in advance. After the simulated use, the stent was observed to see if it was displaced. Then, the stent was pulled off by adhesive tape and tested using a universal tensile testing machine with a test rate of 50.8 mm / min and a gauge length of L = 15 mm to measure the removal force.

[0123] 3. Diameter and other parameters

[0124] In the present invention, the measurements of various parameters such as the diameters of the stent, stent system, and support member are all obtained by using a non-contact measuring instrument.

[0125] 4. Accuracy of stent positioning in bifurcation lesions

[0126] The present invention uses a method to first determine the reference point in DSA angiography, and then determine the two end points a and b of the diseased blood vessel corresponding to the target implantation position of the stent based on the reference point. After the stent is implanted in the blood vessel, the corresponding points of the two end points a' and b' after the actual implantation of the stent are determined by the same reference system method, and then the distance between point a and point a' or between point b and point b' can be obtained. 偏离 |, thereby determining the accuracy of stent positioning in the bifurcation vessel lesion area.

[0127] 5. Balloon retraction diameter ratio N 回抱

[0128] First measure the diameter d of the balloon in the folded state before pressing and gripping the stent 压握前 , and then measure the diameter d after the balloon releases the stent and recovers it in a simulated environment 回收 , the comparison between the two can get the diameter ratio of the balloon back, that is:

[0129] N 回抱 =d 回收 / d 压握前 .

[0130] 6. Burst pressure

[0131] The balloon bursting pressure in the present invention is mainly measured with reference to Appendix A of the standard "YY / T0285.4-2017-Intravascular Catheters - Disposable Sterile Catheters - Part 4 - Balloon Dilatation Catheters". The specific operation method is to soak the balloon in water at 37±2°C for 2 minutes, then use a water pressure tester or a balloon pressure pump to inflate the balloon at a fixed rate until it ruptures, and finally measure the corresponding pressure value.

[0132] 7. Pressure relief time

[0133] The balloon decompression time in this invention is primarily measured with reference to Appendix D of the standard "YY / T0285.4-2017 - Intravascular Catheters - Single-Use Sterile Catheters - Part 4: Balloon Dilatation Catheters." The specific procedure is to inflate the balloon to the RBP using a balloon pressure pump in a 37±2°C water bath. Maintain pressure for 30 seconds, then release pressure until the balloon is deflated. The time from the start of decompression to balloon deflation is recorded.

[0134] Examples 1-16

[0135] This group of embodiments provides the rated diameter d of the balloon of each embodiment, the inner diameter value k of the distal end of the balloon, the cone angle α1 of the first cone, the length L1 of the first cone, the cone angle α2 of the second cone, the length L2 of the second cone, and the roughness Ra of the balloon surface. 囊体 , the roughness of the first cone surface Ra 锥部 , the roughness of the inner surface of the bracket Ra 支内 , the roughness of the outer surface of the bracket Ra 支外 , the maximum static friction force f on the balloon surface in the stent system max and other parameters, respectively, the stent system loaded by the balloon dilatation catheter with the above-mentioned specific features was implanted in the bifurcation vessel lesion of the pulmonary artery of the dog, and the measurement parameter of the positioning accuracy of the stent in the bifurcation vessel lesion of the pulmonary artery of the dog was measured according to the above-mentioned test method. 偏离 |Ratio of the balloon's embrace diameter to the balloon's embrace diameter 回抱 The specific parameters of each embodiment are as follows (see Table 1):

[0136] Table 1 Specific design parameters of the balloons in each embodiment from Example 1 to Example 16, and performance parameters of the balloon dilatation catheters with these design features

[0137] Example 17

[0138] This embodiment is based on Example 3, in which a protrusion is provided on the first cone. The distance between the highest part of the protrusion and the central axis of the balloon is 5.0 mm, and the horizontal distance between the highest part of the protrusion and the adjacent end of the balloon body is 1.5 mm. The total length of the protrusion accounts for 10% of the total length of the first cone. The protrusion and the balloon body form a "V" shape with the opening facing the balloon body, and the angle of the "V" is 150°. The positioning accuracy of the stent at the bifurcation vascular lesion of the dog's pulmonary artery |d 偏离 | is 0.35mm, and the balloon's embrace diameter ratio is 2.21.

[0139] Example 18

[0140] This embodiment is based on Example 3, in which a protrusion is provided on the first cone. The distance between the highest part of the protrusion and the central axis of the balloon is 9.0 mm, and the horizontal distance between the highest part of the protrusion and the adjacent end of the balloon body is 1.2 mm. The total length of the protrusion accounts for 35% of the total length of the first cone. The protrusion and the balloon body form a "V" shape lying flat with the opening facing the balloon body, and the angle of the "V" is 30°. The positioning accuracy of the stent at the bifurcation vascular lesion of the dog's pulmonary artery is |d 偏离 | is 0.38mm, and the balloon's embrace diameter ratio is 2.24.

[0141] Examples 19-25

[0142] For the sake of convenience, the present invention adds the relevant parameters of the balloon dilatation catheter on the basis of Example 12 to further illustrate the influence of the various parameters of the balloon dilatation catheter on its related performance. However, it does not mean that the parameters of the balloon dilatation catheter have any limiting effect on the parameters of the balloon. Here, the parameters of the balloon and the parameters of the balloon dilatation catheter are independent and do not affect each other. In each embodiment, the inner diameter D of the proximal connector is mainly limited. 近内 , the gap G between the push tube and the proximal joint, the wall thickness W3 of the proximal joint and its thickness W of the push tube 推 The ratio N 壁厚 The ratio of the radial cross-sectional area of ​​the filling cavity to the radial cross-sectional area of ​​the push tube is S 径 , the maximum width of the filling cavity in the radial direction W 充max , the minimum wall thickness of the guidewire lumen W 导min , the minimum wall thickness W of the filling cavity 充min , the diameter d of the front end of the guide tube 引 and its diameter ratio N to the second connecting part 引直 , as well as the performance parameters of the balloon dilatation catheter with specific structural features corresponding to each embodiment, such as the pressure relief time T, the balloon burst pressure Pa, and the profile of the balloon after compression and gripping. The specific parameters of each embodiment are as follows (see Table 2):

[0143] Table 2 Specific design parameters of the balloon and balloon dilatation catheter in each embodiment 19 to embodiment 25, and performance parameters of the balloon dilatation catheter with these design features

[0144] The stent was implanted in the bifurcation vascular lesion of the dog's pulmonary artery by using the balloon dilatation catheter in each of the above embodiments. During the operation, the guidewire can be flexibly pulled and drawn in the guidewire cavity, and the guide tube can be smoothly inserted into the blood vessel, guiding the balloon to smoothly enter the blood vessel. In the process of pushing the balloon into the blood vessel, the stent is accurately pushed to the narrow target blood vessel. After the medium is introduced into the filling cavity, the balloon expands smoothly and expands the stent to the rated diameter. The balloon expands for a period of time without rupture. After that, the balloon completes pressure relief within a certain period of time. After the pressure relief, the process of withdrawing the balloon from the body is smooth, and the stent is accurately released at the target blood vessel. At the same time, it can be seen that the narrow target blood vessel is effectively expanded by the stent, meeting the surgical expectations.

[0145] In order to further illustrate the technical effects of the balloon dilatation catheter proposed in the embodiment of the present invention, the comparative example is now described to provide a supplementary explanation.

[0146] Comparative Example 1

[0147] The design of the balloon dilatation catheter in this embodiment is basically the same as that in Example 1, except that the cone angle α1 of the first cone on the distal body 12 of the balloon 1 is 10°, the length of the first cone shoulder of the distal body 12 is 20 mm, and the length L1 of the first cone is 30 mm.

[0148] When the balloon dilatation catheter was used to implant a stent in the dog's pulmonary artery, the guidewire was smoothly inserted into the guidewire lumen 211 and could be flexibly pulled and moved. The balloon 1 was smoothly inserted into the body and smoothly pushed into the blood vessel. However, when it was pushed to the lesion area at the bifurcation, after the medium was introduced into the filling lumen 212, the balloon 1 was able to expand smoothly to the rated diameter. However, during the expansion process, under the action of the branch blood vessels, the balloon and the stent moved backward together, eventually resulting in|d 偏离 |It reached 4.5mm, the stent was not positioned accurately and did not fully cover the lesion area.

[0149] Comparative Example 2

[0150] The design of the balloon dilatation catheter in this embodiment is basically the same as that in embodiment 3, except that the cone angle α1 of the first cone on the distal body 12 of the balloon 1 is 120°, and the cone of the distal body 12 is steeper.

[0151] When the balloon dilatation catheter is used to implant a stent in the dog's pulmonary artery, the guidewire can be smoothly inserted into the guidewire cavity 211 and can be flexibly pulled and moved. However, due to the steep cone of the distal body 12, it is difficult to insert the balloon 1 into the body, and the insertion port needs to be enlarged. The process of pushing it into the blood vessel is also relatively slow. In the process of pushing it to the stenosis of the branch blood vessel, the distal body 12 does not cause damage to the surrounding branch blood vessels. However, due to the large cone angle α1 of the first cone, the stent moves forward relative to the balloon during the balloon expansion process, which ultimately leads to |d 偏离 |It reached 4.8mm, the stent was not positioned accurately and did not fully cover the lesion area.

[0152] Comparative Example 3

[0153] The design of the balloon dilatation catheter in this embodiment is basically the same as that in embodiment 21, except that the ratio of the radial cross-sectional area of ​​the filling cavity 212 to the radial cross-sectional area of ​​the pushing tube 21 is S. 径 is 0.1.

[0154] When using the balloon dilatation catheter to implant a stent in a dog's pulmonary artery, the guidewire can be smoothly inserted into the guidewire lumen 211 and can be flexibly pulled and moved. The balloon 1 can be smoothly inserted into the body and pushed to the stenotic lesion of the branch blood vessel. The distal body 12 does not cause damage to the surrounding branch blood vessels. After the medium is introduced into the filling lumen 212, the balloon 1 can smoothly expand to the rated diameter and open the stenotic blood vessel, but the expansion takes a long time. The balloon 1 remains inflated for a period of time without rupture. Afterwards, the balloon 1 completes pressure relief within 25 seconds. The time required for pressure relief is also long, resulting in a long period of blocked blood flow in the blood vessel, posing a safety hazard. The process of withdrawing the balloon 1 from the body is smooth, and it can be seen that the stenotic blood vessel is effectively opened.

[0155] It can be seen from the data of the above embodiments and comparative examples that by setting the taper of a balloon of a certain diameter within a certain range, the positioning accuracy of the stent can be significantly improved. In addition, by optimizing the length L of the stent cone, the roughness of the surfaces of the balloon and the stent, the maximum static friction between the balloon and the stent, and setting a protrusion on the balloon cone, the positioning accuracy of the stent can be improved to a certain extent. In particular, when the various parameters are combined, the accuracy of the stent at the bifurcation vessel lesion can be significantly improved. That is, the present invention does not require additional structures to improve the positioning accuracy of the stent at the bifurcation vessel lesion, and the preparation of the balloon and stent delivery system is simple and the production cost is low. At the same time, there is no need to sacrifice the profile of the stent system in exchange for the accuracy of the stent positioning, which provides an excellent technical solution for the implantation of stents at bifurcation vessel lesions.

[0156] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A balloon, characterized in that: The balloon comprises a balloon body and a distal body and a proximal body respectively connected to both ends of the balloon body, the balloon body, the distal body and the proximal body are combined to form an inner cavity, the inner cavity is used to accommodate a medium for expanding the balloon, the distal body comprises a first cone portion, the proximal body comprises a second cone portion, at least the cone angle α1 of the first cone portion and the diameter d of the balloon body in the expanded state of the balloon satisfy the following relationship: α1=k1lnd+b1; Among them: k1∈[11, 42.421], and b1∈[6.8, 31.8], 5≤d≤16, and d is a positive integer.

2. The balloon of claim 1, characterized in that The balloon comprises a balloon body and a distal body and a proximal body respectively connected to both ends of the balloon body, the balloon body, the distal body and the proximal body are combined to form an inner cavity, the inner cavity is used to accommodate a medium for expanding the balloon, the distal body comprises a first cone portion, the proximal body comprises a second cone portion, at least the cone angle α1 of the first cone portion and the diameter d of the balloon body in the expanded state of the balloon satisfy the following relationship: α1=k1lnd+b1; Among them: k1∈[11.009, 27.4], and b1∈[7.98, 14.2], 5≤d≤16, and d is a positive integer.

3. The balloon according to claim 1 or 2, characterized in that: The size of the cone angle α1 of the first cone portion and / or the cone angle α2 of the second cone portion and the size of the diameter d of the balloon body in the expanded state of the balloon satisfy the following relationship: α1=k1lnd+b1; Where: k1∈[12, 20], and b1∈[9, 25.8], 5≤d≤16, and d is a positive integer; α2=k2lnd+b2;wherein: k2∈[12,20], and b2∈[9,25.8], 5≤d≤16, and d is a positive integer; The roughness Ra of the capsule surface is 0.03 μm-0.2 μm, and the roughness Ra of the first cone surface is 0.05 μm-0.2 μm.

4. The balloon according to any one of claims 1 to 3, characterized in that: The length L1 of the first cone portion and / or the length L2 of the second cone portion satisfy the following relationship: Where k∈[0.6, 2.1].

5. The balloon according to any one of claims 1 to 4, characterized in that: The length L1 of the first cone portion and / or the length L2 of the second cone portion satisfy the following relationship: Where k∈[0.6, 2.1].

6. The balloon according to any one of claims 1 to 5, characterized in that: The first cone portion and / or the second cone portion comprises at least one protrusion, and a distance D of at least a portion of the protrusion relative to the central axis of the balloon is 1.05-1.5 times of the balloon radius d / 2.

7. The balloon according to any one of claims 1 to 6, characterized in that: The horizontal distance between at least part of the protrusion and the adjacent end of the capsule is less than 2 mm; the total length of the protrusion accounts for 5%-35% of the total length of the first cone or the second cone; the protrusion or its tangent forms a "V" shape lying flat with the opening facing the capsule.

8. The balloon according to any one of claims 1 to 7, characterized in that: The included angle of the "V" shape is 30°-150°.

9. The balloon according to any one of claims 1 to 8, characterized in that: At least the first cone portion includes a stepped structure, the stepped structure includes at least a first cone segment, a second cone segment and a straight segment, the straight segment is connected between the first cone segment and the second cone segment, and the other end of the first cone segment is connected to the capsule; The cone angle α3 of the first cone section is 30°-150°, the cone angle α4 of the second cone section is 40°-178°, and the diameter of the straight section is smaller than the diameter of the capsule.

10. The balloon according to any one of claims 1 to 9, characterized in that: The taper angle α1 of the first taper portion and the taper angle α2 of the second taper portion satisfy the following relationship with the diameter d of the balloon in the expanded state: α1=k1lnd+b1; where: k1∈[11.51, 21.52], d∈[5, 9], b1∈[10.2, 21.4]; or k1∈[21, 27.87], d∈[10, 16], b1∈[-11.6, 3.85]; α2=k2lnd+b2; where: k2∈[11.51,21.52], and d∈[5,9], b2∈[10.2,21.4]; or k2∈[21,27.87], and d∈[10,16], b2∈[-11.6,3.85].

11. The balloon according to any one of claims 1 to 10, characterized in that: The ratio of the wall thickness of the balloon to the diameter of the balloon in the expanded state is 0.0015-0.

010.

12. A balloon dilatation catheter, characterized in that: include: The push tube comprises a guidewire cavity for the guidewire to pass through and a filling cavity for the medium to pass through, wherein the guidewire cavity and the filling cavity are axially arranged in parallel and isolated from each other by a partition; A balloon, which is the balloon according to any one of claims 1 to 11, wherein the balloon is connected to one end of the push tube, and the inner cavity of the balloon is connected to the filling cavity; A catheter seat connected to the other end of the push tube, the catheter seat comprising a first interface and a second interface, the first interface being communicated with the guidewire cavity, and the second interface being communicated with the filling cavity; Wherein, the distal body also includes a distal joint, and the proximal body also includes a proximal joint. At least the proximal joint and the push tube are sealed to form a first connecting part, and the diameter of the first connecting part is less than or equal to the diameter of the proximal joint.

13. The balloon dilatation catheter according to claim 12, characterized in that: The inner diameter of the proximal joint is 1.78 mm-2.2 mm, the gap between the push tube and the proximal joint is no more than 0.2 mm, and the ratio of the wall thickness of the proximal joint to the wall thickness of the push tube is 0.2-2.

0.

14. The balloon dilatation catheter according to claim 12 or 13, characterized in that: The ratio of the radial cross-sectional area of ​​the filling cavity to the radial cross-sectional area of ​​the pushing tube is 0.1-0.3, or along the radial direction of the pushing tube, the maximum width of the filling cavity is 0.3mm-0.55mm.

15. The balloon dilatation catheter according to any one of claims 12 to 14, characterized in that: The balloon dilatation catheter also includes: An inner tube is inserted into the inner cavity of the balloon, one end of the inner tube is connected to the push tube, and the other end of the inner tube is connected to the distal connector; A developing ring, arranged on the inner tube; Wherein, the guide wire cavity is communicated with the inner tube, and the diameter of the inner tube is smaller than the diameter of the push tube.

16. The balloon dilatation catheter according to any one of claims 12 to 15, characterized in that: The distal end joint is connected to the inner tube to form a second connection portion, and the diameter of the second connection portion is smaller than the diameter of the distal end joint.

17. The balloon dilatation catheter according to any one of claims 12 to 16, characterized in that: The balloon dilatation catheter also includes: A guide tube, arranged in front of the distal body along the pushing direction of the pushing tube and connected to the inner tube; Wherein, the ratio of the diameter of the front end of the guide tube to the diameter of the front end of the second connecting part is 0.75-0.

94.

18. The balloon dilatation catheter according to any one of claims 12 to 17, characterized in that: The minimum wall thickness of the guidewire cavity is 0.08 mm to 0.12 mm; and / or the minimum wall thickness of the filling cavity is 0.08 mm to 0.15 mm.

19. A stent system, comprising a stent and the balloon dilatation catheter according to any one of claims 12 to 18, wherein the stent is sleeved on a balloon of the balloon dilatation catheter.

20. The support system according to claim 19, wherein: The roughness Ra of the inner surface of the stent is 0.05 μm-0.4 μm; the maximum static friction force on the surface of the balloon in the stent system is 2.8N-7.9N.

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