A constraint bracket and a balloon catheter having the constraint bracket

Abstract

The present application provides a restraining stent and a balloon catheter with the restraining stent, which are used to restrain the balloon outside the balloon, the restraining stent includes a mesh body and at least one microneedle with a drug on the surface, the mesh body is provided with a plurality of mesh holes, the fixed end of the microneedle is fixed to the mesh body, when the balloon is expanded and unfolded, part of the balloon body protrudes from the mesh holes to form a pillow, and the pillow can push up the free end of the microneedle to a tilted state. The present application arranges a microneedle on the restraining stent, so that the microneedle can be pushed out to a tilted state as the balloon expands, and the microneedle can scratch the diseased tissue during the ejection process, so that the drug can better enter the diseased tissue.

Description

Technical Field

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

[0002] For cardiovascular diseases, balloon angioplasty is one of the most commonly used treatment methods. Traditional balloon angioplasty is often accompanied by blood vessel damage. For example, during the balloon dilation process, the diameters of the proximal and distal ends of the balloon are larger than the diameter of the middle part of the balloon, that is, the "dog bone effect", resulting in excessive dilation of the blood vessels contacted by the two ends of the balloon, causing damage to the blood vessel wall and accelerating the longitudinal elongation of the balloon to cause blood vessel dissection, and at the same time, it can trigger acute blood vessel occlusion at the lesion site and restenosis after the operation. For the new type of drug-eluting balloon catheter with a restraint stent, an anti-proliferative drug and a restraint stent are carried on the surface of the balloon. Although the anti-proliferative drug on the balloon surface can be transferred when contacting the plaque in the blood vessel, the drug usually only acts 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 restraint stent provided with microneedles capable of carrying drugs. When the restraint stent expands with the balloon, the microneedles can have deeper contact with the diseased tissue, so as to transfer the drug to a deeper position of the diseased tissue.

[0004] A first aspect of the present application provides a restraint stent for restraining the balloon on the outer side of the balloon. The restraint stent includes a reticular main body and at least one microneedle with a drug carried on the surface. A plurality of mesh holes are provided on the reticular main body. The fixed end of the microneedle is fixed to the reticular main body. When the balloon expands and unfolds, a part of the balloon body protrudes from the mesh holes to form a pillow part, and the pillow part can lift the free end of the microneedle to a tilted state.

[0005] Further, before the balloon expands and unfolds, the extending direction of the microneedle is parallel to the direction from the proximal end to the distal end of the reticular main body.

[0006] Further, the free end of the microneedle points to the distal end of the reticular main body.

[0007] Further, before the balloon expands and unfolds, the free end of the microneedle does not extend beyond the outer peripheral side of the reticular main body.

[0008] Further, along the direction from the free end to the fixed end, the microneedle sequentially includes a needle tip, a needle body and a needle base. Among them, the width of the needle base 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] Further, before the balloon is inflated and deployed, in the flattened state of the reticular main body, the mesh holes are rhombic, the fixed end is fixed at one interior angle of the rhombus, and the angle of the interior angle δ satisfies: 15° ≤ δ ≤ 30°;

[0010] After the balloon is inflated and deployed, the flattened deployment area of the mesh holes S satisfies: 4 mm 2 ≤ S ≤ 10 mm 2 .

[0011] Further, the length of the microneedles L satisfies: 1.5 mm ≤ L ≤ 3 mm.

[0012] Further, the outer surface of the reticular main body carries drugs, and / or the outer surface of the balloon carries drugs.

[0013] Further, when the balloon is inflated and deployed, a concave groove is formed between two adjacent pillow parts on the bladder body, and the height difference between the highest point of the pillow part and the lowest point of the groove part h satisfies: 0.2 mm ≤ h ≤ 0.6 mm.

[0014] The second aspect of the present application provides a balloon catheter, including a balloon and the restraint bracket.

[0015] The technical solutions provided by the embodiments of the present application may include the following beneficial effects:

[0016] In the present application, by providing microneedles carrying drugs on the restraint bracket, when the restraint bracket is inflated and deployed with the balloon, the pillow parts formed by the bladder body bulging out of the mesh holes of the balloon can lift the microneedles carrying drugs to a tilted state. During the process of the microneedles tilting and in the final tilted state, the microneedles can make deeper contact with the diseased tissues in the blood vessel and even partially penetrate into the diseased tissues, so that the drugs carried on the microneedles can be transferred to deeper positions of the diseased tissues to better exert the drug effect. Description of the Drawings

[0017] Figure 1 is a schematic structural diagram of the balloon catheter of the present application after being inflated and deployed in the body;

[0018] Figure 2 is a schematic structural diagram of an embodiment of the balloon of the present application;

[0019] Figure 3 is a partial flattened view of the restraint bracket of the present application in the contracted state;

[0020] Figure 4 is Figure 3 The partial enlarged view of position A in

[0021] Figure 5 is Figure 1 The partial enlarged view of position B in

[0022] Figure 6 is the schematic diagram of the rotation angle range of the microneedle;

[0023] Figure 7 is the schematic structural diagram of the microneedle according to an embodiment of the present application;

[0024] Figure 8 is the flat view of the reticular main body in the present application when contracting and expanding in an embodiment.

[0025] Reference numerals:

[0026] 100, restraint bracket; 11, reticular main body; 12, connecting portion; 13, fixing portion; 111, mesh hole; 112, microneedle; 1121, free end; 1122, fixed end; 1123, needle tip; 1124, needle body; 1125, needle base; 200, balloon; 21, bladder; 211, pillow portion; 212, groove portion; 22, shoulder; 23, pin. Detailed Description of the Invention

[0027] The following describes in detail the specific embodiments of the present application with reference to the accompanying drawings.

[0028] In the description of the present application, the proximal end and the distal end are defined with reference to the position where the operator can or cannot see during the use of the instrument, that is, the distal end refers to the end of the instrument or component that is relatively far from the operator, and the proximal end refers to the end of the instrument or component that is relatively close to the operator.

[0029] As Figure 1 shown, the present application discloses a balloon catheter, which includes a balloon 200 and a restraint bracket 100 disposed on the outer peripheral side of the balloon 200, and the restraint bracket 100 is used to restrain the radial deformation degree of the balloon 200.

[0030] The structural schematic diagram of the balloon 200 is as Figure 2 shown. The balloon 200 includes a bladder 21 in the middle, and shoulders 22 and pins 23 on both sides of the bladder 21. Both ends of the bladder 21 are 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 fully inflated state, with the side having a larger cross-sectional area connected to the bladder 21 and the side having a smaller cross-sectional area connected to the pin 23.

[0031] The structural schematic diagram of the restraint bracket 100 is as 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] The surface of the microneedle 112 is sprayed or dip-coated with a drug, which can be an anti-intimal hyperplasia drug, such as rapamycin, paclitaxel or its derivatives. When the microneedle 112 punctures 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 part 211 of the bulging mesh hole 111 on the balloon 200 to gradually drive the microneedle 112 to rotate to the tilted state. The microneedle 112 does not simply cut through the diseased tissue in the blood vessel. At the same time, during the entire movement process of the microneedle 112, the drug carried on its outside can also be transferred to the punctured and penetrated parts. Compared with some solutions of carrying drugs on the outer surface of the balloon, the microneedle 112 in the present application can deliver anti-intimal hyperplasia drugs such as rapamycin to a relatively deep position of the diseased tissue, with more significant drug delivery effect and lower drug dosage.

[0036] In some embodiments, the surface of the balloon 200 and the reticular main body 11 can also carry anti-intimal hyperplasia drugs. As shown above, during the rotation of the microneedle 112, it will also cause a certain degree of scratching to the diseased tissue. At this time, the drugs carried on the surfaces of the balloon 200 and the reticular main body 11 can also be transferred to the scratched diseased tissue and the surface of the diseased tissue. In this way, around the set position of the microneedle 112, through the arrangement of carrying drugs on the outer surfaces of the microneedle 112, the balloon 200 and the reticular main body 11, different depths of the diseased tissue can come into contact with the drug, and the drug delivery effect is better.

[0037] The wall thickness of the arterial blood vessel wall is generally 1 mm to 2 mm. If the arterial blood vessel has severe calcified lesions, the thickness of the arterial blood vessel wall will increase significantly. At this time, the wall thickness of the blood vessel is equal to the original normal blood vessel wall thickness plus the thickness of the calcified layer, and its value is generally greater than 3 mm. In order to enable the microneedle 112 to penetrate deeper into the blood vessel tissue, the length of the microneedle 112 L satisfies: 1.5 mm ≤ L ≤ 3 mm.

[0038] As Figure 7 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 satisfies: 8° ≤ β ≤ 15°, and the length of the needle tip 1123 L 1 satisfies: 0.5 mm ≤ L 1 ≤ 1 mm. With such a setting, not only does the needle tip 1123 have better strength, but the pointed head can also better penetrate the diseased tissue, especially the calcified diseased tissue.

[0039] The angle formed by the two sides of the needle body 1124 γ satisfies: 2° ≤ γ≤5°, the length of the needle body 1124 L 2 Satisfies: 1 mm ≤ L 2 ≤ 2 mm. Such that the needle body 1124 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 withdrawn from the diseased tissue and restored to its original shape. One end of the needle body 1124 is connected to one end of the needle hub 1125, and the other end of the needle hub 1125 is connected to the mesh body 11. The width of the needle hub 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 hub 1125 makes the strength distribution of the microneedle 112 more uniform and the connection with the mesh body 11 more firm.

[0040] Before the balloon 200 expands and unfolds, the microneedle 112 is in a received state. At this time, the free end 1121 of the microneedle 112 does not extend beyond the outer peripheral side of the mesh body 11, where 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, it is not easy for the microneedle 112 to cut and damage non-diseased vascular tissues during the insertion process of the balloon catheter, and the insertion process is easier to operate.

[0041] In some embodiments, before the balloon 200 expands and unfolds, the extending 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 not specifically stated, parallel means substantially parallel, rather than geometrically parallel in a strict sense, and a certain angle is allowed between the two. Therefore, the extending direction of the microneedle 112 being parallel to the direction from the proximal end to the distal end of the mesh body 11 means that the extending direction of the microneedle 112 is generally parallel to the length direction of the mesh body 11. The reason for such a setting 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 penetrating deeper into the diseased tissue without increasing the radial dimension of the mesh body 11.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] refer to Figure 8 As stated, Figure 8 The tiling diagrams of the same mesh body in two states of contraction and expansion are shown, such as 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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 balloon catheter, comprising a balloon (200) and a restraining stent (100), wherein the restraining stent (100) is used to restrain the balloon (200) outside the balloon (200), and is characterized in that, The constraint bracket (100) includes a mesh body (11) and at least one microneedle (112) with drugs loaded on its surface. The length of the microneedle (112) L satisfies: 1.5 mm ≤ L ≤ 3 mm. A number of mesh holes (111) are provided on the mesh body (11). The fixed end (1122) of the microneedle (112) is fixed to the mesh body (11). Before the balloon (200) expands and unfolds, when the mesh body (11) is in a flat state, the mesh holes (111) are rhombus-shaped, and the fixed end (1122) is fixed to one of the interior angles of the rhombus. After the balloon (200) expands and unfolds, the flat unfolded area of the mesh holes (111) S satisfies: 4 mm 2 ≤ S ≤ 10 mm 2 ; When the balloon (200) expands and unfolds, a part of the balloon body (21) of the balloon (200) protrudes from the mesh hole (111) to form a pillow part (211), and the pillow part (211) can lift the free end (1121) of the microneedle (112) to a tilted state. A concave groove part (212) is formed between two adjacent pillow parts (211) on the balloon body (21). The height difference between the highest point of the pillow part (211) and the lowest point of the groove part (212) h Satisfies: 0.2mm ≤ h ≤ 0.6mm.

2. The balloon catheter according to claim 1, characterized in that, Before the balloon (200) is inflated and deployed, the extending 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 balloon catheter according to claim 2, wherein, The free end (1121) of the microneedle (112) points to the distal end of the mesh body (11).

4. The balloon catheter according to claim 2, wherein 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 balloon catheter according to claim 2, characterized in that, Along the direction from the free end (1121) to the fixed end (1122), the microneedle (112) successively includes a needle tip (1123), a needle body (1124) and a needle base (1125), wherein the width of the needle base (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 balloon catheter according to claim 5, wherein Before the balloon (200) is inflated and deployed, when the net-like main body (11) is in a flattened state, the angle of the inner corner δ satisfies: 15° ≤ δ ≤ 30°.

7. The balloon catheter according to claim 1, characterized in that, The outer surface of the mesh body (11) carries drugs, and / or the outer surface of the balloon (200) carries drugs.

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