Restraint stent and balloon catheter with same

Abstract

The invention provides a restraining support and a balloon catheter with the restraining support, the restraining support is used for restraining a balloon on the outer side of the balloon, the restraining support comprises a net-shaped main body and at least one microneedle with the surface loaded with medicine, a plurality of net holes are formed in the net-shaped main body, the fixed end of the microneedle is fixed to the net-shaped main body, and the fixed end of the microneedle is fixed to the net-shaped main body. When the balloon is expanded and expanded, part of the balloon body of the balloon protrudes out of the meshes to form a pillow part, and the pillow part can jack up the free end of the microneedle to be in a tilting state. The microneedles are arranged on the restraint stent, so that the microneedles can be ejected out to be in a tilting state along with the expansion of the balloon, and the microneedles can scratch and pierce diseased tissues in the ejection process, so that medicines can better enter the diseased tissues.

Description

Technical Field

[0001] The present application relates to the field of medical devices, and in particular to a restraining stent and a balloon catheter having the restraining stent. Background Art

[0002] Balloon angioplasty is one of the most commonly used treatments for cardiovascular diseases. Traditional balloon angioplasty is often accompanied by vascular damage. For example, during the balloon expansion process, the diameter of the proximal and distal ends of the balloon is larger than the diameter of the middle part of the balloon, which is the "dog bone effect", resulting in excessive expansion of the blood vessels in contact with the two ends of the balloon, causing damage to the vascular wall and causing the longitudinal elongation of the balloon to accelerate vascular dissection. It can also cause acute vascular occlusion and postoperative restenosis at the lesion site. For the new constrained drug balloon catheter, the surface of the balloon carries anti-proliferative drugs and constrained stents. Although the anti-proliferative drugs on the surface of the balloon can be transferred when in contact with the plaque in the blood vessel, the drugs usually only act on the outer surface of the plaque, and the anti-proliferative effect is extremely limited. Especially for some old plaques, the scope and effect of the drug efficacy are significantly limited. Summary of the invention

[0003] In view of this, the present application provides a constrained stent, which is provided with microneedles that can be used to carry drugs. When the constrained stent is expanded with the balloon, the microneedles can have deeper contact with the diseased tissue, thereby transferring the drug to a deeper position of the diseased tissue.

[0004] A first aspect of the present application provides a constraint bracket for constraining a balloon on the outside of the balloon, the constraint bracket comprising a mesh body and at least one microneedle with a drug on its surface, the mesh body being provided with a plurality of mesh holes, the fixed end of the microneedle being fixed to the mesh body, when the balloon is inflated and unfolded, part of the balloon body protrudes from the mesh holes to form a pillow, and the pillow can lift the free end of the microneedle to a tilted state.

[0005] Furthermore, before the balloon is inflated and deployed, the extension direction of the microneedle is parallel to the direction from the proximal end to the distal end of the mesh body.

[0006] Furthermore, the free end of the microneedle points to the distal end of the mesh body.

[0007] Furthermore, before the balloon is inflated and deployed, the free ends of the microneedles do not extend beyond the outer peripheral side of the mesh body.

[0008] Furthermore, along the direction from the free end to the fixed end, the microneedle includes a needle tip, a needle body and a needle seat in sequence, wherein the width of the needle seat is greater than the width of the needle body, and the width of the needle body is greater than the width of the needle tip.

[0009] Furthermore, before the balloon is inflated and deployed, the mesh body is in a flat state, the mesh is in a rhombus shape, the fixed end is fixed to an inner angle of the rhombus, and the angle of the inner angle is δ Satisfaction: 15°≤ δ ≤30°; After the balloon is inflated and deployed, the flattened deployment area of ​​the mesh is S Meet: 4mm 2 ≤ S ≤10mm 2 .

[0010] Furthermore, the length of the microneedle L Meet: 1.5mm≤ L ≤3mm.

[0011] Furthermore, the outer surface of the mesh body is loaded with drugs, and / or the outer surface of the balloon is loaded with drugs.

[0012] Furthermore, when the balloon is expanded and deployed, a concave groove is formed between two adjacent pillows on the balloon body, and the height difference between the highest point of the pillow and the lowest point of the groove is h Meet: 0.2mm≤ h ≤0.6mm.

[0013] A second aspect of the present application provides a balloon catheter, comprising a balloon and the constraining stent.

[0014] The technical solution provided by the embodiments of the present application may have the following beneficial effects: The present application arranges drug-loaded microneedles on a constraining stent. When the constraining stent is expanded and unfolded with the balloon, the pillow portion formed by the bulging mesh of the balloon body can lift the drug-loaded microneedles to a tilted state. During the tilting process of the microneedles and in the final tilted state, the microneedles can come into deeper contact with the diseased tissue in the blood vessels and even partially penetrate the diseased tissue, thereby allowing the drugs on the microneedles to be transferred to deeper positions in the diseased tissue to better exert their efficacy. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the structure of the balloon catheter of the present application after expansion and deployment in vivo; Figure 2 It is a structural schematic diagram of an embodiment of a balloon of the present application; Figure 3 is a partial flattened diagram of a restraining bracket in a contracted state according to an embodiment of the present application; Figure 4 yes Figure 3 A partial enlarged view of the middle A; Figure 5 yes Figure 1 A partial enlarged view of point B in the middle; Figure 6 is a schematic diagram of the microneedle rotation angle range; Figure 7 is a schematic diagram of the structure of a microneedle according to an embodiment of the present application; Figure 8 It is a flattened diagram of the mesh body of one embodiment of the present application when it is contracted and expanded.

[0016] Reference numerals: 100, restraining bracket; 11, mesh body; 12, connecting part; 13, fixing part; 111, mesh; 112, microneedle; 1121, free end; 1122, fixed end; 1123, needle tip; 1124, needle body; 1125, needle seat; 200, balloon; 21, balloon body; 211, occipital part; 212, groove part; 22, shoulder part; 23, pin. DETAILED DESCRIPTION

[0017] The specific implementation of the present application will be described in detail below with reference to the accompanying drawings.

[0018] In the description of this application, the proximal end and the distal end are defined with reference to the position of the operator when the instrument is visible or invisible during use, that is, the distal end refers to the end of the instrument or component itself that is relatively far away from the operator, and the proximal end refers to the end of the instrument or component itself that is relatively close to the operator.

[0019] like Figure 1 As shown, the present application discloses a balloon catheter, which includes a balloon 200 and a constraining stent 100 disposed on the outer circumference of the balloon 200 , wherein the constraining stent 100 is used to constrain the radial deformation degree of the balloon 200 .

[0020] The structure of the balloon 200 is shown in FIG. Figure 2 The balloon 200 includes a balloon body 21 in the middle, and shoulders 22 and pins 23 on both sides of the balloon body 21. The two ends of the balloon body 21 are respectively fixedly connected to one end of the shoulder 22, and the other end of the shoulder 22 is connected to the pin 23. The shoulder 22 is approximately a cone in the inflated state, with the side with a larger cross-sectional area connected to the balloon body 21 and the side with a smaller cross-sectional area connected to the pin 23.

[0021] The structure of the restraining bracket 100 is shown in FIG. Figure 3As shown. The restraint bracket 100 includes: a mesh body 11, a connecting portion 12 and a fixing portion 13. Among them: the two sides of the mesh body 11 are respectively connected to one end of the connecting portion 12, and the other end of the connecting portion 12 is connected to the fixing portion 13. The connecting portion 12 includes a plurality of connecting wires, one end of which is connected to the mesh body 11, and the other end is connected to the trough of the fixing portion 13. The fixing portion 13 adopts a sinusoidal shape, and the height difference between the crest and the trough is 2mm~4mm. The sinusoidal shape can make the restraint bracket 100 expand appropriately when assembled with the balloon 200, so that the balloon 200 can pass through the restraint bracket 100. At the same time, the height difference between the crest and the trough is selected to be 2mm~4mm, which can increase the fixed contact area between the fixing portion 13 and the two ends of the balloon 200, and improve the connection strength between the two.

[0022] When the constraint bracket 100 is sleeved on the outside of the balloon 200, the fixing parts 13 at both ends of the constraint bracket 100 are respectively fixed to the pins 23 at both ends of the balloon 200, so as to fix the constraint bracket 100 and the balloon 200 to each other and prevent the displacement of the balloon 200. The fixing part 13 and the pins 23 at both ends of the balloon 200 can be fixed by hot air welding, glue bonding or laser welding.

[0023] like Figure 1 and Figure 5 As shown in , the initial state of the balloon 200 is a contracted state. When the balloon 200 is filled with a filling expansion medium, the balloon 200 will gradually expand. As the balloon 200 expands, the constraint bracket 100 sleeved on the outside of the balloon 200 expands accordingly. When the balloon 200 expands to a certain extent, under the dual effects of the internal pressure and the constraint of the constraint bracket 100, the balloon 200 drives part of the balloon body 21 of the balloon 200 to bulge out of the mesh 111 of the mesh body 11, and the bulged balloon 200 forms a pillow 211 protruding from the mesh body 11, and forms a concave groove 212 between adjacent pillows 211. When the balloon 200 expands to a predefined maximum extent, the state of the constraint bracket 100 is defined as an expanded state.

[0024] like Figure 4 As shown, Figure 4 yes Figure 3 A partial enlarged view of point A in the middle. The fixed end 1122 of the microneedle 112 is fixed on the mesh body 11 corresponding to the edge of the mesh 111. As the balloon 200 expands or contracts, the microneedle 112 can rotate within a certain angle range. When the balloon 200 expands and unfolds, the microneedle 112 is lifted up by the pillow portion 211 so that the free end 1121 is lifted up to a tilted state. In the process of the microneedle 112 being lifted up, the microneedle 112 can scratch and penetrate the diseased tissue of the groove portion 212.

[0025] The surface of the microneedle 112 is sprayed or dipped with a drug, which can be an anti-intimal hyperplasia drug, such as rapamycin, paclitaxel or its derivatives. When the microneedle 112 scratches the diseased tissue, the drug carried on the surface of the microneedle 112 can enter deeper into the diseased tissue. Compared with the existing cutting balloon, the microneedle 112 in the present application relies on the pillow 211 of the bulging mesh 111 on the balloon 200 to gradually drive the microneedle 112 to rotate to a tilted state. The microneedle 112 does not simply scratch the diseased tissue in the blood vessel. At the same time, during the entire movement of the microneedle 112, the drug carried on its outside can also be transferred to the scratched and pierced part. Compared with some balloon surface drug-loading solutions, the microneedle 112 in the present application can deliver anti-intimal hyperplasia drugs such as rapamycin to relatively deep positions of the diseased tissue, with more significant drug administration effects and lower dosage.

[0026] In some embodiments, the surface of the balloon 200 and the mesh body 11 may also be loaded with anti-intimal hyperplasia drugs. As shown above, the microneedle 112 will also cause a certain degree of scratches to the diseased tissue during the rotation process. At this time, the drugs carried on the surface of the balloon 200 and the mesh body 11 can also be transferred to the scratched diseased tissue and the surface of the diseased tissue. In this way, around the setting position of the microneedle 112, through the setting of the microneedle 112, the balloon 200 and the surface of the mesh body 11, different depths of the diseased tissue can be in contact with the drug, and the drug delivery effect is better.

[0027] The thickness of the arterial wall is generally 1 mm to 2 mm. If the artery is severely calcified, the thickness of the arterial wall will increase significantly. At this time, the thickness of the arterial wall is equal to the original normal wall thickness plus the thickness of the calcified layer, and its value is generally greater than 3 mm. In order to allow the microneedle 112 to penetrate deeper into the vascular tissue, the length of the microneedle 112 is controlled. L Meet: 1.5mm≤ L ≤3mm.

[0028] like Figure 7 As shown, in some embodiments, the microneedle 112 includes a needle tip 1123, a needle body 1124, and a needle seat 1125. The angle formed by the two sides of the needle tip 1123 β Satisfaction: 8°≤ β ≤15°, tip length 1123 L 1Satisfy: 0.5mm≤ L 1 ≤1mm. Such a configuration not only makes the needle tip 1123 have better strength, but also enables the tip to better penetrate the diseased tissue, especially the calcified diseased tissue.

[0029] The angle formed by the two sides of the needle body 1124 γ Satisfaction: 2°≤ γ≤5°, length of needle body 1124 L 2 Meet: 1mm≤ L 2 ≤2mm. The needle body 1124, which serves as the main drug carrier, not only has a large drug-loading area, but also has a smooth transition design with the needle tip 1123. The needle body 1124 can smoothly penetrate into the diseased tissue along with the needle tip 1123 and inject the carried drug into the diseased tissue. When the balloon 200 is depressurized, the needle body 1124 can also be quickly pulled out of the diseased tissue and return to its original shape. The other end of the needle body 1124 is connected to one end of the needle seat 1125, and the other end of the needle seat 1125 is connected to the mesh body 11. The width of the needle seat 1125 is greater than the width of the needle body 1124, and the width of the needle body 1124 is greater than the width of the needle tip 1123. The width design of the needle tip 1123, the needle body 1124 and the needle seat 1125 makes the strength distribution of the microneedle 112 more uniform and the connection with the mesh body 11 more secure.

[0030] Before the balloon 200 is inflated and deployed, the microneedle 112 is in a contained state, at which the free end 1121 of the microneedle 112 does not exceed the outer peripheral side of the mesh body 11, wherein the outer peripheral side is the outer contour surface of the mesh body 11. Since the free end 1121 of the microneedle 112 does not exceed the outer peripheral surface of the mesh body 11, the microneedle 112 is not easy to scratch and damage non-lesioned vascular tissue during the insertion of the balloon catheter, and the insertion process is easier to operate.

[0031] In some embodiments, before the balloon 200 is inflated and deployed, the extension direction of the microneedle 112 is parallel to the direction from the proximal end to the distal end of the mesh body 11. In the description of the present application, if it is not specifically stated that parallel means substantially parallel, rather than geometrically parallel in a strict sense, and a certain angle is allowed between the two. Therefore, the extension direction of the microneedle 112 is parallel to the direction from the proximal end to the distal end of the mesh body 11, which means that the extension direction of the microneedle 112 is substantially parallel to the length direction of the mesh body 11. The reason for this arrangement is that when the length direction of the microneedle 112 is the same as the axial direction of the mesh body 11, the microneedle 112 can have a certain length, which is convenient for piercing deeper into the diseased tissue without increasing the radial dimension of the mesh body 11.

[0032] When the extension direction of the microneedle 112 is parallel to the direction from the proximal end to the distal end of the mesh body 11, no matter whether the free end 1121 of the microneedle 112 points to the distal end or the proximal end of the mesh body 11, before the balloon 200 is first expanded and unfolded, the free end 1121 of the microneedle 112 will never exceed the peripheral side of the mesh body 11. However, once the balloon 200 needs to be retracted after expansion, that is, after the balloon 200 changes from the expanded state to the contracted state, the microneedle 112 may be at risk of not being able to fully rebound to the initial state due to excessive deformation, and the free end 1121 of the microneedle 112 may protrude from the peripheral side of the mesh body 11. In this way, when the restraining balloon is withdrawn from the body, it may be affected by the slightly tilted microneedle 112. In order to avoid this situation, the free end 1121 of the microneedle 112 can be set to point to the distal end of the mesh body 11.

[0033] Figure 6 The figure shows the angle relationship between the microneedle 112 and the axial direction of the mesh body 11 in the received state and the tilted state. The free end 1121 of the microneedle 112 can rotate around the fixed end 1122. In the received state, the angle between the microneedle 112 and the axial direction of the mesh body 11 is α 1Satisfy: 0°≤ α 1≤5°, so that the microneedle 112 is in a state where it does not substantially extend beyond the outer periphery of the mesh body 11, and the free end 1121 can also be slightly retracted to form a small angle α 1. Effectively control the radial dimension of the constraining stent 100 so that it does not increase due to the presence of the microneedle 112, making it easier to place and remove the balloon catheter. α 2 meets, 60°≤ α 2≤90°. In this case, the microneedle 112 has a longer puncture distance and a deeper puncture depth, and can better deliver the drug to the deep part of the diseased tissue in the blood vessel, resulting in a better drug delivery effect.

[0034] When the balloon 200 is inflated and deployed, there is a height difference between the highest point of the pillow 211 and the lowest point of the groove 212. h , height difference h It will affect the tilting angle of the microneedle 112. h The larger the height difference, the more obvious the concave-convex structure (i.e., the pillow and the groove) formed on the surface of the balloon 200, the larger the tilting angle of the microneedle 112, the larger the puncture range, and the more favorable the drug delivery. h It is not the bigger the better. Once the height difference hIf the height difference is too large, not only can the tilting angle of the microneedle 112 not be effectively increased, but it can also easily cause the balloon 200 to rupture due to excessive pressure and the diseased tissue to enter the groove 212. Therefore, in order to ensure that the balloon catheter can effectively squeeze the calcified blood vessel wall and enable the microneedle 112 carrying the drug to effectively penetrate the blood vessel tissue of the groove 212, the height difference is controlled. h Meet: 0.2mm≤ h ≤0.6mm.

[0035] In some embodiments, the mesh 111 is in the shape of a rhombus, and the long diagonal line of the rhombus is parallel to the axial direction of the mesh body 11. This arrangement allows the mesh body 11 to have a relatively small outer contour before the balloon 200 is expanded and deployed, so as to reduce the circumferential size of the constrained stent 100. After the balloon 200 is expanded and deployed, the rhombus mesh is deformed, the short diagonal line becomes longer, and the long diagonal line becomes shorter, until the mesh 111 reaches a stable state.

[0036] refer to Figure 8 As stated, Figure 8 The tiling diagrams of the same mesh body in both contraction and expansion states are shown, e.g. Figure 8 As shown, the mesh body 11 contains n columns of grids, and from the proximal end to the distal end, each column of grids is distributed with m, m-1, m, m-1... meshes 111 (m=10) in sequence. Although the figure shows only m-1 meshes in the even-numbered columns, when the mesh body 11 is in a curled state, the number of meshes in the even-numbered columns is also m. The reason is that when it is flattened, one mesh of the even-numbered columns is separated and cannot be displayed. If the mesh body 11 in the figure is curled, a and a', b and b' overlap, and another mesh 111 will be formed. Therefore, in the curled state, the number of meshes contained in each circumference of the mesh body 11 is the same, and n×m meshes 111 will be formed on the surface of the mesh body 11.

[0037] The fixed end 1122 of the microneedle 112 is fixed on the inner corner of the diamond mesh. In order to facilitate the insertion of the balloon catheter, the fixed end 1122 of the microneedle 112 is fixed on the inner corner of the long diagonal of the diamond mesh, and the free end 1121 of the microneedle 112 faces the distal end of the mesh body 11. In some embodiments, each mesh is correspondingly provided with a microneedle 112.

[0038] like Figure 2 As shown, in some embodiments, the angle of the inner angle corresponding to the long diagonal line of the diamond mesh is δ Satisfaction: 15°≤ δ≤30°. When the inner angle satisfies the above relationship, the mesh 111 of the constraining stent 100 can be kept maximally contracted in the contracted state, thereby minimizing the overall outline size of the balloon catheter and facilitating the delivery of the balloon catheter into the human body. At the same time, this angle is also conducive to the mesh 111 shrinking back and shrinking, facilitating the withdrawal of the balloon catheter from the human body.

[0039] When the balloon 200 is expanded and deployed, the diamond mesh will be stretched and deformed to a shape that is approximately square. In order to make balloons 200 of different specifications form obvious concave-convex structures when expanded and deployed, to ensure that calcified tissue can enter the groove 212, to facilitate the insertion of the microneedle 112, and to ensure that the microneedle 112 can be accommodated in the mesh 111 as a whole before the balloon 200 is expanded and deployed, the flattened deployment area of ​​the mesh 111 is controlled when the balloon 200 is expanded and deployed. S Meet: 4mm 2 ≤ S ≤10mm 2 When the area of ​​mesh 111 is S If the size is too small, not only the microneedle 112 cannot be accommodated in the mesh 111, but also the height of the balloon 200 protruding from the mesh 111 becomes smaller, affecting the formation of the pillow portion 211 and the groove portion 212. S When the height of the balloon 200 protruding from the mesh 111 is too large, the height difference between the pillow portion 211 and the groove portion 212 is increased. h If the size of the mesh 111 is too large, the adjacent occipital parts 211 will be too close together, resulting in the inability of calcified tissue to enter the groove 212, affecting the penetration effect of the microneedle 112. At the same time, when the area of ​​the mesh 111 becomes larger, the number of meshes in the mesh body 11 will decrease, and the number of microneedles 112 will decrease, further affecting the drug delivery effect.

[0040] In some embodiments, the mesh body 11 and the microneedle 112 are integrally cut and formed by a metal round tube, and the integral forming makes the connection between the mesh body 11 and the microneedle 112 stable. The material of the metal round tube can be a nickel-titanium alloy with shape memory and superelasticity, so that the stent 100 can rebound to the initial state after expansion.

Claims

1. A restraining stent, used to restrain a balloon (200) outside the balloon (200), characterized in that: The restraining stent (100) comprises a mesh body (11) and at least one microneedle (112) with a drug on its surface, the mesh body (11) being provided with a plurality of mesh holes (111), the fixed end (1122) of the microneedle (112) being fixed to the mesh body (11), and when the balloon (200) is expanded and unfolded, a part of the balloon body (21) of the balloon (200) protrudes from the mesh hole (111) to form a pillow portion (211), and the pillow portion (211) can lift the free end (1121) of the microneedle (112) to a tilted state.

2. The restraining bracket according to claim 1, characterized in that: Before the balloon (200) is inflated and deployed, the extension direction of the microneedle (112) is parallel to the direction from the proximal end to the distal end of the mesh body (11).

3. The restraining bracket according to claim 2, characterized in that: The free end (1121) of the microneedle (112) points to the distal end of the mesh body (11).

4. The restraining bracket according to claim 2, characterized in that: Before the balloon (200) is inflated and deployed, the free end (1121) of the microneedle (112) does not extend beyond the outer peripheral side of the mesh body (11).

5. The restraining bracket according to claim 2, characterized in that: Along the direction from the free end (1121) to the fixed end (1122), the microneedle (112) comprises a needle tip (1123), a needle body (1124) and a needle seat (1125) in sequence, wherein the width of the needle seat (1125) is greater than the width of the needle body (1124), and the width of the needle body (1124) is greater than the width of the needle tip (1123).

6. The restraining bracket according to claim 5, characterized in that: Before the balloon (200) is inflated and deployed, the mesh body (11) is in a flat state, the mesh (111) is in a rhombus shape, the fixed end (1122) is fixed to an inner corner of the rhombus, and the angle of the inner corner is δ Satisfaction: 15°≤ δ ≤30°; After the balloon (200) is expanded and deployed, the flattened deployment area of ​​the mesh (111) is S Meet: 4mm 2 ≤ S ≤10mm 2 .

7. The restraining bracket according to claim 6, characterized in that: The length of the microneedle (112) L Meet: 1.5mm≤ L ≤3mm.

8. The restraining bracket according to claim 1, characterized in that: The outer surface of the mesh body (11) is loaded with drugs, and / or the outer surface of the balloon (200) is loaded with drugs.

9. The restraining bracket according to claim 1, characterized in that: When the balloon (200) is inflated and deployed, an inwardly concave groove (212) is formed between two adjacent pillows (211) on the balloon body (21), and the height difference between the highest point of the pillow (211) and the lowest point of the groove (212) is h Meet: 0.2mm≤ h ≤0.6mm.

10. A balloon catheter, characterized in that: It comprises a balloon (200) and the restraining stent (100) as claimed in any one of claims 1 to 9.

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