Expanded polytetrafluoroethylene artificial blood vessel with integrated support rings and preparation method therefor

Abstract

Provided are an expanded polytetrafluoroethylene artificial blood vessel with integrated support rings and a preparation method therefor. Support rings and expanded polytetrafluoroethylene tubular membranes are alternately distributed in an equally spaced configuration, and an expanded polytetrafluoroethylene flat-sheet membrane is wound on the outside of the support rings and the expanded polytetrafluoroethylene tubular membranes, so as to effectively improve the compression resistance and flexural resistance of the artificial blood vessel, while also improving the longitudinal extensibility of the artificial blood vessel; the support rings are of an integrated structure, and do not loosen or shift, thereby solving the problem of artificial blood vessels bending, flattening, and twisting during use when subjected to external forces.

Description

An integrated support ring of expanded polytetrafluoroethylene artificial blood vessel and a preparation method thereof TECHNICAL FIELD

[0001] The present application belongs to the technical field of artificial blood vessels, and particularly relates to an expanded polytetrafluoroethylene artificial blood vessel with an integrated support ring and a preparation method thereof. BACKGROUND

[0002] In recent years, the incidence of vascular diseases and uremia has been increasing year by year, which has become a serious threat to the further improvement of people's quality of life, and is also a major factor leading to high morbidity and mortality in modern society. Cardiovascular disease is usually associated with vascular stenosis or obstruction. When the blood vessel is narrowed, the blood flow will be reduced, which will cause the blood vessel to be severely blocked, and blood vessel replacement is needed. Hemodialysis is the main way of kidney replacement therapy for uremia patients. As the "lifeline" of hemodialysis, the selection and establishment of vascular access is crucial, and vascular grafts have become one of the main ways to build vascular access. At present, the available vascular grafts mainly include autologous blood vessels and artificial blood vessels. Compared with autologous blood vessels, artificial blood vessels have the advantages of wide material sources, good structure controllability, strong adaptability, low immune response, etc., and the market demand is growing rapidly.

[0003] At present, the base material of the artificial blood vessel product with an inner diameter ≤10mm used in clinical practice is mainly expanded polytetrafluoroethylene material. However, expanded polytetrafluoroethylene material is very soft. After the artificial blood vessel is implanted into the human body, when the joint is bent or the muscle tissue is compressed, it is easy to bend, flatten or twist, thereby causing the risk of blood clotting and blocking the blood vessel. In order to solve this problem, patents such as CN110859998A, CN114869541A and CN112472361A all propose to increase a spiral support ring on the outer surface or inside the wall of the artificial blood vessel to improve the anti-bending performance of the blood vessel. However, the general support ring material has high hardness, and winding in a spiral manner on the artificial blood vessel will affect the mechanical properties of the blood vessel itself. For example, patent CN201759698U proposes to set a metal support bracket between the outer layer of the blood vessel and the inner layer of the blood vessel. However, expanded polytetrafluoroethylene material is extremely inert, and has poor adhesion with metal materials. Therefore, during use, the internal metal support bracket is prone to loosen or shift, thereby causing safety risks. SUMMARY

[0004] The purpose of the present application is to provide an expanded polytetrafluoroethylene artificial blood vessel with an integrated support ring and a preparation method thereof, which improves the compression and bending resistance of the artificial blood vessel, and at the same time improves the longitudinal stretching performance of the artificial blood vessel, to solve the problems in the above background.

[0005] To achieve the above object, the present application adopts the following technical scheme: A kind of with integrated support ring's expanded polytetrafluoroethylene artificial blood vessel, including support ring, expanded polytetrafluoroethylene tube membrane and expanded polytetrafluoroethylene flat membrane, wherein: the support ring and expanded polytetrafluoroethylene tube membrane are equidistantly distributed alternately, and the expanded polytetrafluoroethylene flat membrane is wound on the outside of the support ring and expanded polytetrafluoroethylene tube membrane.

[0006] Preferably, the width of the support ring is 0.9-1.1mm, and the interval is 2-4mm.

[0007] Preferably, the thickness of the expanded polytetrafluoroethylene flat membrane is 30-80μm.

[0008] On the other hand, the present application proposes a preparation method of a expanded polytetrafluoroethylene artificial blood vessel with integrated support ring, including the following steps: processing expanded polytetrafluoroethylene tube membrane through artificial blood vessel annular support structure processing equipment to obtain tube membrane with integrated support ring; cutting expanded polytetrafluoroethylene flat membrane into strip-shaped membrane; wrapping the strip-shaped membrane on the outer surface of the tube membrane, and then heating and setting to obtain expanded polytetrafluoroethylene artificial blood vessel with annular support structure.

[0009] Preferably, the processing equipment includes: a rack; a press roller and a drive motor installed on the top and bottom of the rack, the drive motor drives the press roller to rotate through a belt; a heating plate arranged on one side of the press roller; a lead screw for adjusting the interval between the heating plate and the press roller, the lead screw is threadedly connected to the rack, and the end is rotatably connected to the heating plate; a guide plate arranged inside the rack and located at the bottom of the heating plate and the press roller; and a mandrel for sleeving the expanded polytetrafluoroethylene tube membrane between the heating plate and the press roller.

[0010] Preferably, the surface of the heating plate is provided with arc-shaped heating teeth, the width of the heating teeth is 0.9-1.1mm, and the interval of the heating teeth is 2-4mm.

[0011] Preferably, the processing of the expanded polytetrafluoroethylene tube membrane through the artificial blood vessel annular support structure processing equipment to obtain the tube membrane with integrated support ring includes the following steps: sleeving the expanded polytetrafluoroethylene tube membrane on the mandrel; adjusting the gap between the heating plate and the press roller through the lead screw, and then heating the heating plate after the gap adjustment is completed; placing the mandrel with the tube membrane at the inlet of the gap between the heating plate and the press roller, starting the drive motor to make the mandrel uniformly roll down along the gap; collecting the mandrel with the tube membrane from the outlet of the guide plate and then cooling the mandrel at room temperature; and taking off the tube membrane from the mandrel.

[0012] Preferably, the heating temperature of the heating plate is 350-380℃.

[0013] Preferably, the temperature of the heating setting is 350-450 DEG C.

[0014] Preferably, the width of the strip-shaped film is 9.9-10.1 mm.

[0015] Technical effects and advantages of the present application: the artificial blood vessel with integrated support ring and the preparation method thereof have the following advantages compared with the prior art.

[0016] In the present application, the support ring and the expanded polytetrafluoroethylene tube film are alternately distributed at equal intervals, and the expanded polytetrafluoroethylene flat film is wound outside the support ring and the expanded polytetrafluoroethylene tube film, which can effectively improve the compression and folding resistance of the artificial blood vessel, and can improve the longitudinal stretchability of the artificial blood vessel. In addition, through the artificial blood vessel support ring processing equipment, without introducing other materials, the support ring with a certain strength can be directly added on the expanded polytetrafluoroethylene tube. The support ring is an integrated structure and will not loosen or displace. The processing method is simple and efficient, solves the problems of bending, flattening and kinking of the artificial blood vessel caused by external forces during use, makes each support ring exist independently, reduces the kinking between the rings, does not affect the longitudinal elastic recovery of the artificial blood vessel, improves the compression and bending resistance of the artificial blood vessel during clinical use, and makes the inner and outer walls of the artificial blood vessel smooth, effectively reducing the occurrence of thrombosis and infection. BRIEF DESCRIPTION OF DRAWINGS

[0017] Fig. 1 is a structural schematic view of the expanded polytetrafluoroethylene artificial blood vessel of the present application;

[0018] Fig. 2 is a schematic view of the expanded polytetrafluoroethylene tube film of the present application;

[0019] Fig. 3 is a structural schematic view of the support ring processing equipment of the present application;

[0020] Fig. 4 is a structural schematic view of the pressure roller, heating plate and mandrel of the present application;

[0021] Fig. 5 is a three-dimensional structural schematic view of the heating plate of the present application;

[0022] Fig. 6 is a front view structural schematic view of the heating plate of the present application. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The specific embodiments described herein are only used to explain the present application, and are not used to limit the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application. Embodiment

[0024] The embodiment of the present application provides a kind of expanded polytetrafluoroethylene artificial blood vessel with integral support ring as shown in Figure 1-2, the inner diameter of the artificial blood vessel is 4-10mm, wall thickness is 0.5-0.7mm, including support ring 9, expanded polytetrafluoroethylene tube membrane 10 and expanded polytetrafluoroethylene flat membrane 11, wherein: support ring 9 and expanded polytetrafluoroethylene tube membrane 10 are alternately distributed at equal intervals, and expanded polytetrafluoroethylene flat membrane 11 is wound outside support ring 9 and expanded polytetrafluoroethylene tube membrane 10.

[0025] Further, the width of support ring 9 is 0.9-1.1mm, and the interval is 2-4mm.Expanded polytetrafluoroethylene flat membrane 11 is high-strength expanded polytetrafluoroethylene film, which can effectively improve the suture pulling strength of artificial blood vessel, and the thickness is 30-80 μm.

[0026] In the embodiment, by alternately distributing support ring and expanded polytetrafluoroethylene tube membrane at equal intervals, and winding expanded polytetrafluoroethylene flat membrane outside support ring and expanded polytetrafluoroethylene tube membrane, the compression and folding resistance of artificial blood vessel can be effectively improved, and the longitudinal expansion performance of artificial blood vessel can be improved. Embodiment

[0027] The embodiment of the present application provides a support ring processing equipment as shown in Figure 4-6, which is used for processing support ring, and the processing equipment comprises a rack (not marked in the figure), a driving motor 1, a pressing roller 3, a heating plate 4, a mandrel 5 and the like.

[0028] Specifically, the pressing roller 3 is rotatably installed at the top of the rack, the driving motor 1 is fixed at the bottom of the rack, and the driving motor 1 drives the pressing roller 3 to rotate through the belt 2, as shown in Figure 4, the driving motor 1 and the pressing roller 3 are connected with a belt pulley for installing the belt 2.

[0029] The heating plate 4 is arranged on one side of the pressing roller 3, the lead screw 8 is threadedly connected to the rack, and the end is rotatably connected to the heating plate 4, and the lead screw 8 is used for adjusting the interval between the heating plate 4 and the pressing roller 3.In addition, a guide rod (not shown in the figure) is arranged between the heating plate 4 and the rack, for limiting the angle of the heating plate 4.The surface of the heating plate 4 is provided with arc-shaped heating teeth, the width of the heating teeth is 0.9-1.1mm, and the interval of the heating teeth is 2-4mm.

[0030] The guide plate 7 is arranged inside the rack and located at the bottom of the heating plate 4 and the pressing roller 3, and is used for supporting the mandrel 5; the mandrel 5 is located between the heating plate 4 and the pressing roller 3 for sleeving the expanded polytetrafluoroethylene tube membrane sleeve 6.

[0031] Specifically, the expanded polytetrafluoroethylene is a porous material with a "fiber-node" network structure, and the existence of fiber pores makes the expanded polytetrafluoroethylene very soft and elastic. The prepared expanded polytetrafluoroethylene tube film is sleeved on the mandrel 5, and the outer diameter of the mandrel 5 should be slightly larger than the inner diameter of the tube film to avoid the tube film sliding on the mandrel 5. The gap between the heating plate 4 and the pressure roller 3 is adjusted by the lead screw 8, and after the gap is adjusted, the heating plate 4 is heated to 350-380℃. Then the mandrel 5 sleeved with the tube film is placed on the outer surface of the pressure roller 3, and the pressure roller 3 can roll under the action of the driving motor 1. At this time, the mandrel 5 rolls down along the gap between the heating plate 4 and the pressure roller 3 under the action of its own gravity and the biting action of the pressure roller 3. The heating plate 4 has many "heating teeth", and during the rolling down of the mandrel 5, the heating teeth will act on the outer surface of the tube film with a certain pressure and heat to melt it (the melting point of polytetrafluoroethylene material is 327℃). Finally, the mandrel 5 will roll down along the guide plate 7 and be collected. In this process, the part in contact with the heating teeth is heated and compacted at high temperature, and the microporous structure is destroyed, finally forming a hard annular structure. The hardness of this part increases, and good radial support effect is produced, while the other parts still maintain the original soft and fluffy state. Embodiment

[0032] In this embodiment, a method for preparing an expanded polytetrafluoroethylene artificial blood vessel with an integrated support ring is provided, which comprises the following steps:

[0033] An expanded polytetrafluoroethylene tube film with an inner diameter of 5.5mm and a wall thickness of 0.5mm is prepared by the method of "extrusion-stretching-heat setting", and the tube film 6 is processed by the artificial blood vessel annular support structure processing equipment to obtain a tube film with an integrated support ring 9;

[0034] Specifically, the expanded polytetrafluoroethylene tube film is sleeved on a mandrel 5 with an outer diameter of 5.7mm; the gap between the heating plate 4 and the pressure roller 3 is adjusted by the lead screw 8 to 6.5mm, and after the gap is adjusted, the heating plate 4 is heated to 350-380℃; the mandrel 5 sleeved with the tube film is placed at the entrance of the gap between the heating plate 4 and the pressure roller 3, and the driving motor 1 is started to make the mandrel 5 roll down uniformly along the gap;

[0035] The mandrel 5 sleeved with the tube film is collected from the outlet of the guide plate 7 and then cooled at room temperature, and the tube film is removed from the mandrel 5;

[0036] The expanded polytetrafluoroethylene flat film with a thickness of 50μm is cut into a strip-shaped film, and the width of the strip-shaped film is 9.9mm-10.1mm;

[0037] The strip-shaped film is wrapped on the outer surface of the tube film, and then is heated and shaped at 350-450 DEG C to obtain the expanded polytetrafluoroethylene artificial blood vessel with annular support structure.

[0038] By means of the artificial blood vessel support ring processing equipment, the support ring with certain strength can be directly added on the expanded polytetrafluoroethylene tube without introducing other materials, the support ring is of integral structure and cannot be loosened or displaced, the processing mode is simple and efficient, the problems of bending, flattening and kinking of the artificial blood vessel caused by external force in the use process are solved, each support ring exists independently, the kinking between the rings is reduced, the longitudinal elastic recovery of the artificial blood vessel is not affected, the performance of the artificial blood vessel in resisting flattening and bending in the clinical use process is improved, the inner and outer walls of the artificial blood vessel are smooth, and the occurrence of thrombosis and infection is effectively reduced.

[0039] Finally, it should be noted that: the above only for the preferred embodiments of the present application, and not for limiting the present application, although the foregoing embodiments of the present application are described in detail, for those skilled in the art, it still can be modified, or part of the technical features of the equivalent replacement, within the spirit and principles of the present application, any modification, equivalent replacement, improvement, etc., should be included in the protection scope of the present application.

Claims

1. A porous expanded polytetrafluoroethylene vascular prosthesis comprising an integral support ring, wherein the support ring is formed by a plurality of interconnected struts. The support ring, the expanded polytetrafluoroethylene tube membrane and the expanded polytetrafluoroethylene flat membrane are alternately arranged at equal intervals, and the expanded polytetrafluoroethylene flat membrane is wound outside the support ring and the expanded polytetrafluoroethylene tube membrane. The width of the support ring is 0.9-1.1 mm, and the interval is 2-4 mm.

2. The expanded polytetrafluoroethylene vascular graft with integral support ring of claim 1, wherein: The thickness of the expanded polytetrafluoroethylene flat membrane is 30-80 μm.

3. The expanded polytetrafluoroethylene vascular graft with integral support ring of claim 1, wherein: The steps include:

4. A method of producing a porous expanded polytetrafluoroethylene vascular prosthesis with integral support rings according to any one of claims 1 to 3, characterized in that, The expanded polytetrafluoroethylene tube membrane is processed by the artificial blood vessel annular support structure processing equipment to obtain a tube membrane with an integrated support ring. The expanded polytetrafluoroethylene flat membrane is cut into a strip-shaped membrane. The strip-shaped membrane is wrapped outside the tube membrane, and then heated and shaped to obtain an expanded polytetrafluoroethylene artificial blood vessel with an annular support structure. The processing equipment includes:

5. The method of claim 4, wherein: a rack; a pressurizing roller and a driving motor installed on the top and bottom of the rack, the driving motor driving the pressurizing roller to rotate through a belt; a heating plate arranged on one side of the pressurizing roller; a lead screw for adjusting the interval between the heating plate and the pressurizing roller, the lead screw being threadedly connected to the rack and having an end rotatably connected to the heating plate; a guide plate arranged inside the rack and located at the bottom of the heating plate and the pressurizing roller; and a mandrel for sleeving the expanded polytetrafluoroethylene tube membrane between the heating plate and the pressurizing roller. The surface of the heating plate is provided with arc-shaped heating teeth, the width of the heating teeth is 0.9-1.1 mm, and the interval of the heating teeth is 2-4 mm.

6. The method of claim 5, wherein: The steps of processing the expanded polytetrafluoroethylene tube membrane by the artificial blood vessel annular support structure processing equipment to obtain a tube membrane with an integrated support ring include:

7. The method of claim 6, wherein: sleeving the expanded polytetrafluoroethylene tube membrane on the mandrel; adjusting the gap between the heating plate and the pressurizing roller through the lead screw, and then heating the heating plate after the gap adjustment is completed; placing the mandrel with the sleeved tube membrane at the inlet of the gap between the heating plate and the pressurizing roller, starting the driving motor to make the mandrel uniformly roll down along the gap; collecting the mandrel with the sleeved tube membrane from the outlet of the guide plate and then cooling the mandrel at room temperature; taking the tube membrane off the mandrel. The heating temperature of the heating plate is 350-380℃.

8. The method of claim 7, wherein: The temperature of the heating and shaping is 350-450℃.

9. The method of claim 7, wherein: The width of the strip-shaped membrane is 9.9 mm-10.1 mm.

10. The method of claim 7, wherein: ​

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