CN114939012A - Intravascular stent system and processing method thereof - Google Patents

Abstract

The invention belongs to the technical field of medical instruments, and particularly relates to a vascular stent system and a processing method thereof. A vascular stent system comprising a stent having a radial crush force that decreases from a proximal end to a distal end; the balloon conveying system comprises a cylindrical balloon, a tip connected to one end of the balloon, an outer tube connected to the other end of the balloon and an inner tube connected to the other end of the tip, wherein the inner tube penetrates through the middles of the balloon and the outer tube and forms a pressure channel with the tip, the balloon and the outer tube, and the compliance of the balloon is gradually increased from the near end to the far end; when the saccule contracts, the stent is pressed on the outer wall of the saccule, and when the saccule expands, the stent is separated from the saccule. In the technical scheme, the inventor sets the support strength of the stent from the proximal end to the distal end to be a gradually reduced structure, so that the strong support strength required by the proximal end of the blood vessel can be met, and the weak support strength required by the distal end of the blood vessel can be met.

Description

A kind of blood vessel stent system and its processing method

technical field

The invention belongs to the technical field of medical devices, in particular to the technical field of A61L, and more particularly relates to a blood vessel stent system and a processing method thereof.

Background technique

Currently, diffuse intermittent stenotic lesions in blood vessels are often treated by implanting multiple stents or by implanting a long stent to completely cover the entire lesion area. Implanting multiple stents often brings a variety of problems, such as inaccurate positioning of multiple stents; there is a risk of stacking between stents; non-stenotic parts of stents adjacent to stents may be stimulated by stent implantation and post-implantation. Changes in the hemodynamics of the non-implanted segment are likely to cause thrombosis or stenosis. Implanting a long stent to completely cover the entire lesion area will also bring a variety of problems. For example, the long blood vessels of the lesion are often a tapered structure that gradually narrows from the proximal end to the end, but the long stent will be a It is a dilated structure with a uniform diameter from proximal to distal, so it is easy to cause excessive tearing of distal vessels and in-stent restenosis. Since the existing long stent is a uniform structure, the smaller stenosis at the distal end of the lesion is likely to occur. Or the small blood vessels will be strongly supported by the same stent structure as the proximal end of the lesion, which is likely to cause greater stimulation to the distal lesion and cause in-stent restenosis.

There is an urgent need for stents with different supporting strengths, which can be used in the treatment of diffuse intermittent stenotic lesions.

SUMMARY OF THE INVENTION

For the purposes of the following detailed description, it should be understood that the present invention may employ various alternative variations and sequences of steps, unless expressly stated to the contrary.

In order to solve the above technical problems, a first aspect of the present invention provides a vascular stent system, including a stent, the radial compression resistance of the stent is gradually reduced from the proximal end to the distal end; a balloon delivery system, the The balloon delivery system comprises a cylindrical balloon, a tip connected to one end of the balloon, an outer tube connected to the other end of the balloon, and an inner tube connected to the other end of the tip, the inner tube running through the balloon and the outer tube. The middle part forms a pressure channel with the tip, the balloon and the outer tube, and the compliance of the balloon gradually increases from the proximal end to the distal end; when the balloon contracts, the stent is pressed against the outer wall of the balloon, and when the balloon is deflated, the stent is pressed against the outer wall of the balloon. The stent disengages from the balloon during expansion.

The stent is delivered to the lesion through the balloon delivery system, and the balloon is filled with gas or liquid through the pressure channel formed by the balloon to realize the expansion of the balloon, so that the stent is expanded and supported on the inner wall of the blood vessel to achieve Dilation and support of blood vessels. The inventor designed the stent to have a structure in which its radial anti-compression force gradually decreases from the proximal end to the distal end. When the stent is used for the treatment of diffuse intermittent stenosis in the blood vessel, due to the tapered and gradually narrowing of the blood vessel. Structure, for the proximal end of the blood vessel, due to the larger diameter and greater hemodynamics, the stent needs to provide strong support, that is, a larger radial anti-extrusion force, for the distal end of the blood vessel due to the smaller diameter and smaller hemodynamics, the stent needs to provide weaker support, that is, weaker radial anti-extrusion force. In this technical solution, the inventor designed the support strength of the stent from the proximal end to the distal end to be a gradually decreasing structure, which can not only satisfy the strong supporting strength required by the proximal end of the blood vessel, but also meet the weaker supporting strength required by the distal end of the blood vessel. support strength. In addition, the compliance of the balloon gradually increases from the proximal end to the distal end, and the balloon is adapted to the stent, which can ensure that each section of the stent achieves better expansion and support.

As a preferred technical solution, the manner in which the radial compression resistance force of the stent is gradually reduced from the proximal end to the distal end is one of linear gradual reduction or step-by-step reduction.

As a preferred technical solution, the manner in which the compliance of the balloon gradually decreases from the proximal end to the distal end is one of a linear gradual decrease or a stepwise decrease.

As a preferred technical solution, the bracket includes a plurality of supporting beams and connecting rods connecting the supporting beams, and the supporting beams are in a wave shape formed by repeated extensions of convex peaks and concave valleys.

As a preferred technical solution, the stent is formed by connecting M sections, wherein M≥1, and the balloon is formed by connecting N sections, wherein M=N, for each section of the stent, the balloon is Correspondingly, the stent can be pressed and held on the outer wall of the balloon when the balloon is deflated, and the stent can be separated from the balloon when the balloon is expanded.

As a preferred technical solution, the compliance of each of the N segments of the balloon is greater than or equal to 105%.

As a preferred technical solution, the stent is formed by connecting three sections. From the proximal end to the distal end, there are a first section of stent, a second section of stent and a third section of stent. The radial direction of the first section of stent is Anti-extrusion force>1.5N/mm, the radial anti-extrusion force of the second-stage stent is 1.0N/mm-1.5N/mm, and the radial anti-extrusion force of the third-stage stent<1.0N /mm.

As a preferred technical solution, the beam width of the support beam of the first section of the bracket is 150-200um, the curvature of the peaks and valleys is 2Π/3-5Π/6, and the support beam of the second section of the bracket is 150-200um. The beam width is 100-150um, the radian of the convex peaks and valleys is Π/2-2Π/3, the beam width of the support beam of the third bracket is 50-100um, and the radians of the convex peaks and valleys are Π /3-Π/2.

The test standard of the radial anti-extrusion force described in this technical solution is ISO25539-2, and the magnitude of the radial anti-extrusion force can represent the support strength of the stent.

The inventor found that the support strength of the stent can be changed by adjusting the range of the beam width of the support beam and the curvature of the peaks and valleys. However, if the beam width is too large, the crimpability of the stent on the balloon will be reduced. The greater the curvature of the peaks and valleys, the better the support for the blood vessels, but when the stent is delivered to the lesion, the stent is prone to fall off, and the curvature of the peaks and valleys is relatively high. If it is too small, the supporting strength of the stent will be greatly reduced, and the transportation resistance of the stent in the blood vessel will be increased. The inventors found that by designing the beam width and the curvature of the peaks and valleys of different parts of the stent, the stent can achieve different support in different lengths, so that it can be applied to diffuse intermittent stenotic lesions, and can be used for different lesions. have different supports.

As a preferred technical solution, the balloon is formed by connecting three sections, wherein from the proximal end to the distal end are the first section of the balloon, the second section of the balloon and the third section of the balloon, wherein the first section of the balloon The length of the segment balloon is the same as the length of the first segment of the stent, the length of the second segment of the balloon is the same as the length of the second segment of the stent, and the length of the third segment of the balloon is the same as the length of the third segment of the stent. The compliance of the segment balloon is 105%-110%, the compliance of the second segment balloon is 118%-130%, and the compliance of the third segment balloon is greater than 130%.

The compliance of the balloon = ΦD _RBP /ΦD _Normal , where ΦD _RBP is the diameter of the balloon under nominal pressure, mm; where ΦD _Normal is the diameter of the balloon under nominal pressure, mm.

As a preferred technical solution, the material of the first-stage balloon is selected from one of polyether block polyamide, thermoplastic polyurethane elastomer, silicic acid gel, thermoplastic elastomer TPE/TPR and polyurethane.

As a preferred technical solution, the material of the second section of the balloon is selected from one of PA12, polyether block polyamide and polyethylene terephthalate.

As a preferred technical solution, the material of the third-stage balloon is selected from one of PA11, PA12, polyethylene terephthalate and polyether block polyamide.

By selecting the materials of different length sections of the balloon, the inventors make the balloon corresponding to different length sections of the stent have different compliances, that is, different expansion capabilities, so that each section of the stent with different supporting strengths has better expandability. .

As a preferred technical solution, one end of the balloon is connected to the tip through a first conical transition end, and the other end is connected to the outer tube through a second conical transition end, and the first conical transition end is connected to the outer tube. The angle formed between the balloons may or may not be equal to the angle formed between the second tapered transition end and the balloon.

The second aspect of the present invention provides the preparation method of the vascular stent system, which at least includes the following steps:

(1) Preparation of balloon delivery system;

(2) Preparation of stents;

(3) Press and hold the stent on the balloon.

Beneficial effects:

In this technical solution, the inventors set the supporting strength of the stent from the proximal end to the distal end to a gradually decreasing structure, which can not only satisfy the strong supporting strength required by the proximal end of the blood vessel, but also meet the requirements of the distal end of the blood vessel. weaker support strength. It can not only avoid the overlapping structure of multiple stents when placing multiple stents in the treatment of diffuse intermittent stenosis lesions in the blood vessels, but also avoid providing the same support strength in the entire lesions of the blood vessels, causing excessive tearing of the blood vessels and causing stents. The problem of restenosis. In addition, the inventors set different compliances on the balloon, so that the balloons have different compliances when corresponding to different stents, so as to achieve uniform expansion of each segment of the stent, so that the stent has better support in the blood vessel.

Description of drawings

FIG. 1 is a schematic diagram of the overall structure of the balloon delivery system in Example 1. FIG.

FIG. 2 is a schematic diagram of the partial structure of the first-stage stent in Example 1. FIG.

1-Balloon, 2-Outer tube, 3-Second tapered transition end, 4-First segment balloon, 5-Second segment balloon, 6-Third segment balloon, 7-First tapered transition end, 8-tip, 9-inner tube, 10-support beam, 11-connecting rod, 12-valley, 13-convex peak.

Detailed ways

Example 1

A vascular stent system includes a stent and a balloon delivery system for transporting the stent. The bracket includes a plurality of supporting beams 10 and connecting rods 11 connecting the supporting beams 10 , and the supporting beams 10 are wave-like formed by repeated extensions of convex peaks 13 and valleys 12 . The stent includes a first section of stent, a second section of stent and a third section of stent in sequence from the proximal end to the distal end, the material of the stent is polylactic acid, the first section of the stent, the second section of the stent and the third section of the stent. The length ratio of the bracket is 1:1:1. As shown in FIG. 2 , the beam width of the support beam 10 of the first bracket is 150um, and the radian of the convex peak 13 and the valley 12 is 3Π/4. The beam width of the supporting beam of the second-stage bracket is 120um, the radian of the convex peak and the valley is 7Π/12, the beam width of the supporting beam of the third-stage bracket is 90um, and the radian of the convex peak and the valley is 5Π/12 . According to the test standard of ISO25539-2, the radial compression resistance of the first segment of the stent is 1.7N/mm, the radial compression resistance of the second segment of the stent is 1.4N/mm, and the radial compression resistance of the third segment of the stent is 1.4N/mm. The extrusion force is 0.9N/mm. By setting different beam widths and radians in each section of the bracket, different supporting properties of different sections of the bracket are realized.

As shown in FIG. 1 , the balloon delivery system includes a cylindrical balloon 1 , which is connected to a tip 8 at one end of the balloon 1 , an outer tube 2 connected to the other end of the balloon 1 , and an inner tube 2 connected to the other end of the tip 8 . Tube 9, the inner tube 9 runs through the middle of the balloon 1 and the outer tube 2 and forms a pressure channel with the tip 8, the balloon 1 and the outer tube 2, and the compliance of the balloon 1 gradually increases from the proximal end to the distal end. Increase; when the balloon 1 is deflated, the stent is pressed against the outer wall of the balloon 1 , and when the balloon 1 is expanded, the stent is separated from the balloon 1 . In vitro and during transportation, the stent is combined with the balloon 1 by crimping. When the stent is transported to the lesion through the balloon 1, the balloon 1 is filled with gas to increase the pressure in the balloon 1. The balloon 1 and the stent are expanded, so that the stent is separated from the balloon 1 to form support for the inner wall of the blood vessel.

The balloon is connected by 3 sections, wherein from the proximal end to the distal end are the first section balloon 4, the second section balloon 5 and the third section balloon 6, in which the stent and the balloon 1 are connected. When crimping is performed, the first section of balloon 4 corresponds to the first section of the stent and has the same length, the second section of balloon 5 corresponds to the second section of the stent and has the same length, and the third section of balloon 6 corresponds to the third section of the stent. The stents correspond to each other and have the same length. The compliance of the first balloon 4 is 108%, the compliance of the second balloon 5 is 125%, and the compliance of the third balloon 6 is 132%. The material of the first section of the balloon 4 is PA12, the material of the second section of the balloon 5 is polyethylene terephthalate, and the material of the third section of the balloon 6 is polyether block polymer. amide.

The compliance of the balloon = ΦD _RBP /ΦD _Normal , where ΦD _RBP is the diameter of the balloon under nominal pressure, mm; where ΦD _Normal is the diameter of the balloon under nominal pressure, mm.

One end of the balloon 1 is connected to the tip 8 through a first tapered transition end 7, and the other end is connected to the outer tube 2 through a second tapered transition end 3, and the first tapered transition end 7 is connected to the balloon. The included angle formed between 1 is equal to the included angle formed between the second tapered transition end 3 and the balloon 1 , wherein the included angle is 155°. When the included angle between the first tapered transition end 7 , the second tapered transition end 3 and the tip 8 is relatively large, the smoothness of the transportation of the balloon in the blood vessel can be improved.

The second aspect of the present embodiment provides the preparation method of the vascular stent system, comprising the following steps:

(1) After blow molding the first, second and third balloons respectively, the first, second and third balloons are welded by laser welding. Welding to form an integral balloon, and then welding the tip, inner tube and outer tube to the balloon to form;

(2) The first-stage support, the second-stage support and the third-stage support are respectively injection-molded to form an integral support by laser welding;

(3) Refer to the method in Patent Application No. 201380057836.9 to crimp the stent on the balloon.

Claims (10)

1. A vascular stent system, characterized in that it comprises a stent, and the radial anti-compression force of the stent is gradually reduced from the proximal end to the distal end; a balloon delivery system, the balloon delivery system comprises a cylindrical ball The balloon is connected to the tip of one end of the balloon, connected to the outer tube of the other end of the balloon, and connected to the inner tube of the other end of the tip, the inner tube penetrates the middle of the balloon and the outer tube and is connected with the tip, the balloon and the outer tube. The tube forms a pressure channel, and the compliance of the balloon gradually increases from the proximal end to the distal end; when the balloon is deflated, the stent is pressed against the outer wall of the balloon, and when the balloon is expanded, the stent is in contact with the balloon. break away. 2 . The vascular stent system according to claim 1 , wherein the radial anti-extrusion force of the stent is gradually reduced from the proximal end to the distal end in a manner of linear gradual reduction or step-by-step reduction. 3 . A sort of. 3 . The vascular stent system according to claim 2 , wherein the manner in which the compliance of the balloon is gradually decreased from the proximal end to the distal end is one of a linear gradual decrease or a stepwise decrease. 4 . 4 . The vascular stent system according to claim 3 , wherein the stent comprises a plurality of supporting beams and connecting rods connecting the supporting beams, and the supporting beams are wavy shapes formed by repeated extensions of convex peaks and concave valleys. 5 . . 5. The vascular stent system according to claim 3, wherein the stent is formed by connecting M segments, wherein M≥1, and the balloon is formed by connecting N segments, wherein M=N, for The corresponding part of each section of the balloon of the stent can realize that the stent is pressed against the outer wall of the balloon when the balloon is deflated, and the stent is separated from the balloon when the balloon is expanded. 6 . The vascular stent system according to claim 5 , wherein the compliance of each of the N segments of the balloon is greater than or equal to 105%. 7 . 7. The vascular stent system according to claim 5, wherein the stent is formed by connecting three sections, and from the proximal end to the distal end are the first section of stent, the second section of the stent and the third section of the stent, The radial anti-extrusion force of the first section of the stent is greater than 1.5N/mm, the radial anti-extrusion force of the second section of the stent is 1.0N/mm-1.5N/mm, and the third section of the stent has a Radial anti-extrusion force <1.0N/mm. 8 . The vascular stent system according to claim 7 , wherein the balloon is formed by connecting three sections, wherein from the proximal end to the distal end, the first section of the balloon, the second section of the balloon and the The third segment of the balloon, wherein the length of the first segment of the balloon is the same as the length of the first segment of the stent, the length of the second segment of the balloon is the same as the length of the second segment of the stent, and the length of the third segment of the balloon is the same as the length of the third segment The length of the stent is the same, the compliance of the first segment of the balloon is 105%-110%, the compliance of the second segment of the balloon is 118%-130%, and the compliance of the third segment of the balloon is greater than 130%. 9. The vascular stent system according to any one of claims 1-8, wherein one end of the balloon is connected to the tip through a first tapered transition end, and the other end is connected to the tip through a second tapered transition end. The outer tubes are connected, and the included angle formed between the first tapered transition end and the balloon is equal to or not equal to the included angle formed between the second tapered transition end and the balloon. 10. A method for preparing a vascular stent system according to claims 1-9, characterized in that, at least the following steps are included: (1) Preparation of balloon delivery system; (2) Preparation of stents; (3) Press and hold the stent on the balloon.

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