Self-expansion stent system for bifurcated blood vessel

Abstract

The invention relates to a self-expansion stent system for a bifurcated blood vessel, the bifurcated blood vessel comprises a lesion blood vessel and a non-lesion blood vessel communicated with the lesion blood vessel, the self-expansion stent system comprises an outer layer sheathing canal, a release tube, an inner tube, a self-expansion stent, a positioning guide wire and a guide guide wire, the release tube is sleeved with the outer layer sheathing canal, and the outer layer sheathing canal is sleeved with the inner tube; the release tube is sleeved outside the inner tube, the self-expansion stent is releasably accommodated between the release tube and the far-end part of the inner tube, the guide wire and the inner tube are in sliding fit along the axial direction and extend into a lesion blood vessel, the positioning guide wire extends into a non-lesion blood vessel, a fixing piece is arranged at the far-end part of the outer sheath tube, and the self-expansion stent is fixed on the outer sheath tube. The fixing part is in sliding fit with the positioning guide wire, so that an included angle is formed between the positioning guide wire and the release tube, the stent can be accurately positioned and released to a required position, the influence of the positioning guide wire on the pressing and holding effect and the wall adhesion of the stent is avoided, and the displacement of the released stent due to withdrawing of the positioning guide wire is prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a self-expanding stent system for bifurcated blood vessels. Background Art

[0002] With the improvement of people's living standards and changes in lifestyle, the incidence of vascular diseases is getting higher and higher. If these diseases are not treated in time, they may cause blood vessel blockage, cause necrosis of surrounding tissues, and seriously endanger the patient's life safety. Minimally invasive interventional surgical treatment methods have been recognized by doctors and patients for their small trauma to patients, high safety, and high effectiveness, and have become an important treatment method for vascular diseases.

[0003] Minimally invasive interventional surgical treatment refers to the implantation of stents in the diseased segment of the blood vessel. The implanted stent can expand the narrowed segment of the blood vessel and support the blood vessel, thereby restoring blood flow in the blood vessel. The implanted stents can be divided into balloon-expandable stents and self-expanding stents. Usually, the self-expanding stent is a tubular mesh structure made by laser cutting of nickel-titanium tubes or weaving of nickel-titanium wires, and the stent is pre-pressed in the stent system. During the operation, the doctor determines the length and diameter of the narrowed segment of the blood vessel with the assistance of imaging equipment, selects a stent of appropriate specifications, pushes the stent system to the distal end of the narrowed part of the blood vessel, and then withdraws the release tube of the stent system to release the stent. After the stent is released, it will self-expand and expand the narrowed segment of the blood vessel to restore blood vessel patency. The key to this operation is to be able to quickly and accurately release the stent in the narrowed segment of the blood vessel so that the stent can cover the lesion. Existing self-expanding stent systems used clinically generally include a support shaft and a release tube. When releasing the stent, the stent system is not accurately positioned due to factors such as shaking during surgical operations and blood vessel pulsation. In particular, when treating lesions in bifurcated blood vessels, the stent system only enters a very small part of the bifurcated blood vessel and the anchoring effect with the blood vessel is very weak, causing the stent to become unstable as the stent system moves during release, and cannot be accurately released at the desired position, thereby failing to cover the lesion well, reducing the treatment effect on the patient and even causing complications.

[0004] Patent CN105266936A discloses a branch vessel stent precision implantation system, wherein the branch vessel includes a main vessel interconnected with each other and a branch vessel connected to the main vessel, the stent precision implantation system includes a stent delivery device that releasably receives and delivers the stent, a guide wire extending from the main vessel to the branch vessel, and a positioning guide wire extending along the main vessel, the stent delivery device is movably sleeved outside the guide wire, a limiting hole is provided on the stent, and the positioning guide wire can slide through the limiting hole. Although the positioning member on the stent is locked with the positioning guide wire and the guide wire to achieve the positioning of the stent system, the positioning member is provided on the stent, which will have a significant impact on the assembly and release of the stent:

[0005] First, when the stent is assembled into the delivery system, it needs to be compressed into a smaller diameter. Since the positioning guide wire passes through the stent, it will hinder the compression of the stent and even damage the connecting rod of the stent.

[0006] Secondly, when the stent is released, since the positioning guide wire passes through the cylindrical surface formed by the stent from the outside to the inside or from the inside to the outside, a section of the stent will inevitably be blocked by the guide wire, hindering its adhesion to the inner wall of the blood vessel.

[0007] Thirdly, after the stent is released, when the guide wire is retracted, the guide wire passing through the stent can easily cause the stent to shift. In severe cases, the guide wire may even get stuck in the positioning piece and cannot be withdrawn. Summary of the invention

[0008] In view of the deficiencies in the prior art, the present invention provides a self-expanding stent system for bifurcated blood vessels, which not only accurately positions the stent and suppresses the stent from moving forward when released, thereby improving the pushing force transmitted by the delivery system, but also avoids the influence of the positioning guide wire on the stent's gripping effect and the stent's wall adhesion, and prevents the stent from being displaced due to the withdrawal of the positioning guide wire after release.

[0009] In order to achieve the purposes of accurate positioning of the stent, suppressing the stent from moving forward when released, and improving the pushing force transmitted by the delivery system, the present invention provides the following technical solutions:

[0010] A self-expanding stent system for a bifurcated blood vessel, wherein the bifurcated blood vessel comprises a diseased blood vessel connected to each other and a non-diseased blood vessel connected to the diseased blood vessel, wherein the self-expanding stent system comprises a release tube, an inner tube, a self-expanding stent, a positioning guide wire and a guide guide wire, wherein the release tube is sleeved outside the inner tube, and the self-expanding stent is releasably received between the release tube and a distal portion of the inner tube, and the guide guide wire forms a sliding fit with the inner tube along the axial direction. During clinical use, the guide guide wire extends into the diseased blood vessel, and the positioning guide wire extends into the non-diseased blood vessel, an outer sheath is sleeved outside the release tube, and a fixing is provided at a distal portion of the outer sheath, and the fixing forms a sliding fit with the positioning guide wire, so that the positioning guide wire and the release tube form an angle, and the top of the angle is stuck at the bifurcation of the blood vessel, thereby fixing the relative position of the stent system and the bifurcated blood vessel, preventing the stent system from being displaced during the surgical operation, and achieving precise positioning.

[0011] In one embodiment, the outer sheath tube is coaxially arranged with the release tube and the inner tube.

[0012] In one embodiment, a support unit is fixedly provided at the distal end portion of the inner tube, and the proximal end of the self-expanding stent is connected to the distal end of the support unit.

[0013] In one embodiment, the fixing element is in the shape of a ring surrounded by wire.

[0014] In one embodiment, the fixing element is tubular, and the distal end of the fixing element does not exceed the distal end of the outer sheath.

[0015] In one embodiment, the fixing member is an open slot, the opening size of the slot is smaller than the outer diameter of the positioning guide wire, and the distal end of the slot does not exceed the distal end of the outer sheath.

[0016] In one embodiment, the distance between the distal end of the fixing element and the distal end of the outer sheath is 0-5 cm.

[0017] In one embodiment, before the self-expanding stent is released, the distance between the distal end of the outer sheath and the distal end of the self-expanding stent is smaller than the length of the self-expanding stent. With this arrangement, when the self-expanding stent is released, the release tube is withdrawn, and the proximal end of the self-expanding stent is first released into the outer sheath, and then the outer sheath is slowly withdrawn to release the entire self-expanding stent into the blood vessel, thereby suppressing the self-expanding stent from moving forward when released.

[0018] In one embodiment, handles are provided at the proximal ends of the outer sheath tube, the release tube and the inner tube to facilitate surgical operations.

[0019] Compared with the prior art, the self-expanding stent system for bifurcated blood vessels provided by the present invention has the following beneficial effects:

[0020] 1. The present invention has an outer sheath disposed outside the release tube, and a fixing part is disposed at the distal end of the outer sheath, so that the positioning guide wire does not contact the self-expanding stent, which can not only accurately release the stent, but also avoid the influence of the positioning guide wire on the stent gripping effect and the stent wall adhesion, and prevent the stent displacement caused by the withdrawal of the positioning guide wire after the stent is released.

[0021] 2. The present invention sets the distance between the distal end of the outer sheath and the distal end of the self-expanding stent to be smaller than the length of the self-expanding stent. Before the self-expanding stent is released, that is, when the self-expanding stent is accommodated in the stent system, the distal end of the outer sheath overlaps with the proximal end of the self-expanding stent, so that the proximal end of the self-expanding stent is first released into the outer sheath, and then the doctor operates the outer sheath to further release the self-expanding stent into the blood vessel. Different from the traditional release tube withdrawal, directly releasing the stent into the blood vessel, the present invention utilizes two step-by-step releases of the stent, reducing the elastic force of the stent released from the tube, thereby inhibiting the stent from jumping forward when released.

[0022] 3. The present invention adds an outer sheath, which improves the rigidity of the entire delivery system, thereby effectively improving the delivery system's ability to transmit pushing force from the proximal end to the distal end, making it easier for the stent system to pass through tortuous, calcified and occluded blood vessels with longer lesion segments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the distal end cross-section of the self-expanding stent system for bifurcated blood vessels of the present invention.

[0024] Figure 2 It is a schematic diagram of the state of the self-expanding stent system for bifurcated blood vessels of the present invention in a blood vessel before the self-expanding stent of the system is released.

[0025] Figure 3 This is a schematic structural diagram of a tubular fixing member of a self-expanding stent system for bifurcated blood vessels of the present invention.

[0026] Figure 4 The present invention is a cross-sectional schematic diagram of a fixing member of a self-expanding stent system for a bifurcated blood vessel in which the fixing member is a tubular outer sheath.

[0027] Figure 5 The present invention is a cross-sectional schematic diagram of a fixing piece of a self-expanding stent system for a bifurcated blood vessel in which the fixing piece is an open card slot.

[0028] Figure 6 It is a schematic diagram of the state of the stent system in the bifurcated blood vessel when the fixing piece of the self-expanding stent system for the bifurcated blood vessel of the present invention is arranged at the distal end of the outer sheath and the self-expanding stent has not been released.

[0029] Figure 7 for Figure 6 A schematic diagram of a distal cross-section of a self-expanding stent system is shown.

[0030] Figure 8 for Figure 6 The diagram shows a state in which the proximal end of the self-expanding stent of the self-expanding stent system has not yet been released.

[0031] Fig. 9 for Figure 6 The self-expanding stent system shown is a schematic diagram of a state in which the self-expanding stent is fully released.

[0032] Fig.10 The schematic diagram of the state of the stent system in the bifurcated blood vessel is shown in FIG. 1 , when the fixing member of the self-expanding stent system for the bifurcated blood vessel of the present invention is arranged at the distal end of the outer sheath and the distance from the distal end of the outer sheath is 0-3 cm and the self-expanding stent has not been released.

[0033] Fig.11 for Fig.10The schematic diagram of the self-expanding stent system is shown in a state where the distal end of the self-expanding stent is released.

[0034] Fig.12 for Fig.10 The diagram shows a state in which the proximal end of the self-expanding stent of the self-expanding stent system has not yet been released.

[0035] Fig.13 for Fig.10 The self-expanding stent system shown is a schematic diagram of a state in which the self-expanding stent is fully released.

[0036] Fig.14 The schematic diagram of the state of the stent system in the bifurcated blood vessel is shown in FIG. 1 , when the fixing member of the self-expanding stent system for the bifurcated blood vessel of the present invention is arranged at the distal end of the outer sheath and is 3-5 cm away from the distal end of the outer sheath, and when the self-expanding stent has not been released.

[0037] Fig.15 for Fig.14 The schematic diagram of the self-expanding stent system is shown in a state where the distal end of the self-expanding stent is released.

[0038] Fig.16 for Fig.14 The self-expanding stent of the self-expanding stent system is shown in a schematic diagram when the self-expanding stent is fully released.

[0039] Fig.17 It is a schematic diagram of the handle structure of the self-expanding stent system for bifurcated blood vessels of the present invention.

[0040] In the figure: 1. Outer sheath; 2. Release tube; 3. Inner tube; 4. Self-expanding stent; 5. Positioning guide wire; 6. Guide guide wire; 7. Fixing piece; 8. Handle; 9. Tip; 10. Support unit; 81. Inner tube handle; 82. Outer sheath handle; 83. Slider. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] Embodiment 1

[0043] like Figure 1 and Figure 2As shown, a self-expanding stent system suitable for bifurcated blood vessels, the bifurcated blood vessels include mutually connected diseased blood vessels and non-diseased blood vessels connected to the diseased blood vessels, the self-expanding stent system includes a release tube 2, an inner tube 3, a self-expanding stent 4, a positioning guide wire 5 and a guide guide wire 6. The release tube 2 is sleeved outside the inner tube 3, the self-expanding stent 4 is releasably received between the release tube 2 and the distal end of the inner tube 3, the guide guide wire 6 and the inner tube 2 form a sliding fit along the axial direction, during clinical use, the guide guide wire 6 extends into the diseased blood vessel, and the positioning guide wire 5 extends into the non-diseased blood vessel. An outer sheath tube 1 is disposed outside the release tube 2, and a fixing member 7 is provided at the distal end of the outer sheath tube 1, the fixing member 7 forms a sliding fit with the positioning guide wire 5, so that the positioning guide wire 5 and the release tube 2 form an angle, the top of the angle is stuck at the bifurcation of the blood vessel, the relative position of the stent system and the bifurcated blood vessel is fixed, and the stent system is prevented from being displaced during the surgical operation, and accurate positioning is achieved. The present invention has an outer sheath disposed on the release tube, and a fixing member is disposed at the distal end of the outer sheath, so that the positioning guide wire does not contact the self-expanding stent, which can accurately release the stent and avoid the influence of the positioning guide wire on the stent gripping effect and the stent wall adhesion, and prevent the stent displacement caused by the withdrawal of the positioning guide wire after the stent is released. In addition, the present invention adds an outer sheath, which improves the rigidity of the entire delivery system, thereby effectively improving the ability of the delivery system to transmit the pushing force from the proximal end to the distal end, making it easier for the stent system to pass through tortuous, calcified and occluded blood vessels with longer lesion segments.

[0044] In one embodiment, the outer sheath 1 is coaxially arranged with the release tube 2 and the inner tube 3, and the outer sheath 1, the release tube 2 and the inner tube 3 are arranged in sequence from outside to inside. A support unit 10 is fixedly arranged at the distal end of the inner tube 3, and the proximal end of the self-expanding stent 4 is connected to the distal end of the support unit 10.

[0045] like Figure 2 and Figure 3 As shown, during clinical surgery, according to conventional vascular interventional surgery, a path for surgical instruments is established using a guide catheter and a guide wire 6. Before the stent system enters the guide catheter, the positioning guide wire 5 is passed through the fixing member 12, and then enters the guide catheter together with the stent system; the guide wire 6 and the inner tube 32 of the stent system form an axial sliding fit to guide the release tube assembly 2 of the stent system into the diseased side of the bifurcated vessel; the positioning guide wire 5 is operated to enter the non-lesioned side of the bifurcated vessel, so that the positioning guide wire 5 and the release tube assembly 2 coaxial with the guide guide wire 6 form an angle, so that it is stuck at the bifurcation of the vessel, fixing the relative position of the stent system and the bifurcated vessel, and realizing the precise release of the subsequent self-expanding stent 4.

[0046] The fixing member 12 can be designed in various forms according to requirements, such as Figure 2 As shown, the fixing member 12 is in the shape of a ring surrounded by a wire, and the inner diameter of the ring is slightly larger than the outer diameter of the positioning guide wire 5, so as to form a sliding fit with the positioning guide wire 5. The structure formed by the fixing member 12 surrounded by a wire can be realized in a variety of ways. First, the two ends of the wire are fixedly buried in the wall of the outer sheath tube, and the middle part of the wire is arranged outside the outer sheath tube, forming a closed ring structure with the outer layer of the outer sheath tube, and the closed ring structure can pass through the positioning guide wire; second, the wire is wrapped around the outer sheath tube, a part of the wire is fixedly buried in the wall of the outer sheath tube, and the other part of the wire is exposed from the outer sheath tube, so as to form an annular structure with a guide wire channel with the outer layer of the outer sheath tube, and the annular structure can slidably pass through the positioning guide wire 5.

[0047] like Figure 1 As shown, a tip 9 is provided at the distal end of the inner tube 3, and the tip 9 is fixedly connected to the inner tube 3. The tip 9 is conical and made of a soft material (such as Pebax, TPU, etc.) to conform to the tortuous blood vessels, so that the stent system can track the guide wire 6 without damaging the blood vessels.

[0048] In one embodiment, the inner or outer walls of the outer sheath 1, the release tube 2 and the inner tube 3 may be provided with a lubricating coating, such as a silicone oil coating or a PTFE coating, to make the inner or outer wall smooth and ensure smooth sliding during clinical use.

[0049] The outer sheath tube 1, the release tube 2 and the inner tube 3 can be configured as a single-layer tube or a multi-layer composite tube, for example, a multi-layer composite tube whose inner layer is made of PTFE. The outer sheath tube 1, the release tube 2 and the inner tube 3 can be tubes of uniform softness or tubes of varying softness, such as a soft distal end and a hard proximal end. For example, the distal end is made of a material with low hardness such as TPU and PEBAX, and the proximal end is made of a material with high hardness such as PA, so that the distal end is soft and can conform to the tortuous blood vessels without damaging the blood vessels, and the proximal end has good hardness, produces good support, can effectively transmit the proximal pushing force to the distal end, and provide better transmission force conduction.

[0050] In a preferred embodiment, the outer sheath 1, the release tube 2 or the inner tube 3 may be provided with an intermediate braided layer to form a braided composite tube, so that the tube body is not easily folded in a tortuous blood vessel to affect its use.

[0051] In one embodiment, if Fig.17As shown, handles 8 are provided at the proximal ends of the outer sheath 1, the release tube 2 and the inner tube 3 to facilitate better surgical operations. Specifically, an outer sheath handle 82 is fixedly installed at the proximal end of the outer sheath 1; an inner tube handle 81 is fixedly installed at the proximal end of the inner tube 3, and a slider 83 is fixedly installed at the proximal end of the release tube 2. The outer sheath handle 82 and the inner tube handle 81 can move axially relative to the stent system, and the slider 83 and the inner tube handle 81 can move axially relative to the stent system.

[0052] Embodiment 2

[0053] The structure of this embodiment is basically the same as that of the first embodiment, except that:

[0054] like Figure 3 and Figure 4 As shown, the fixing member 7 can be designed to be tubular, the inner diameter of the fixing member 7 is slightly larger than the outer diameter of the positioning guide wire 5, and the distal end of the tubular fixing member does not exceed the distal end of the outer sheath 1.

[0055] Embodiment 3

[0056] The structure of this embodiment is basically the same as that of the first embodiment, except that:

[0057] like Figure 5 As shown, the fixing member 7 can be designed as an open slot, the inner diameter of the slot is slightly larger than the outer diameter of the positioning guide wire 5, the opening size of the slot is smaller than the outer diameter of the positioning guide wire 5, and the distal end of the slot does not exceed the distal end of the outer sheath 1.

[0058] Embodiment 4

[0059] The structure of this embodiment is basically the same as that of the first embodiment, except that:

[0060] The distance between the distal end of the fixing member 7 and the distal end of the outer sheath tube 1 is 0-5 cm.

[0061] When the lesion is located at the bifurcation of the blood vessels, such as Figure 6 As shown in FIG. 1 , the distance between the distal end of the fixing member 7 and the distal end of the outer sheath tube 1 can be set to 0. When the stent is released, as shown in FIG. Figure 8 As shown, the inner tube 3 and the outer sheath 1 remain stationary relative to the blood vessel, and the release tube 2 is withdrawn. Since the proximal end of the self-expanding stent 4 is connected to the distal end of the support unit 10 fixed to the inner tube 3, the support unit 10 abuts against the self-expanding stent 4 to prevent it from moving. Therefore, when the release tube 2 moves backward, the self-expanding stent 4 is gradually released from the stent system into the blood vessel from the distal end to the proximal end. In this embodiment, as shown in FIG. Figure 7 As shown, the distal end of the support unit 10 coincides with the distal end of the outer sheath 1, as shown in FIG. Fig. 9As shown, when the release tube 2 is withdrawn to the proximal end of the self-expanding stent 4, the self-expanding stent 4 is no longer constrained by the stent system, so that the self-expanding stent 4 can be completely released into the blood vessel.

[0062] When the lesion is close to the bifurcation of the blood vessel, such as Fig.10 As shown, the distance between the distal end of the fixing member 7 and the distal end of the outer sheath tube 1 can be set to 0-3 cm. Fig.11 As shown, the inner tube 3 and the outer sheath 1 remain stationary relative to the blood vessel, and the release tube 2 is withdrawn. Since the proximal end of the self-expanding stent 4 is connected to the distal end of the support unit 10 fixed to the inner tube 3, the support unit 10 resists the self-expanding stent 4 to prevent it from moving. Therefore, when the release tube 2 moves backward, the self-expanding stent 4 is gradually released from the stent system into the blood vessel from the distal end to the proximal end.

[0063] When the lesion is far from the bifurcation of the blood vessel, such as Fig.14 As shown, the distance between the distal end of the fixing member 7 and the distal end of the outer sheath tube 1 can be set to 3-5 cm. Fig.15 and Fig.16 As shown, the inner tube 3 and the outer sheath 1 remain stationary relative to the blood vessel, and the release tube 2 is withdrawn. Since the proximal end of the self-expanding stent 4 is connected to the distal end of the support unit 10 fixed to the inner tube 3, the support unit 10 resists the self-expanding stent 4 to prevent it from moving. Therefore, when the release tube 2 moves backward, the self-expanding stent 4 is gradually released from the stent system into the blood vessel from the distal end to the proximal end.

[0064] The present application can set different distances between the fixing part 7 and the distal end of the outer sheath as needed, so that the self-expanding stent system can be applied to different lesion locations. During clinical surgery, the lesion is close to the bifurcation of the blood vessel, and the distance between the fixing part and the distal end of the outer sheath is also close, so that the top of the angle formed by the positioning guide wire and the release tube is stuck at the bifurcation of the blood vessel, which is convenient for positioning. Therefore, the doctor can select a suitable stent system according to the actual situation, so that the two ends of the stent are 3-5mm longer than the lesion when it is released, so as to better cover the lesion.

[0065] Embodiment 5

[0066] The structure of this embodiment is basically the same as that of the fourth embodiment, except that:

[0067] Before the self-expanding stent 4 is released, the distance between the distal end of the outer sheath 1 and the distal end of the self-expanding stent 4 is less than the length of the self-expanding stent 4. Therefore, the distal end of the outer sheath 1 overlaps with the proximal end of the self-expanding stent 4 pressed on the inner tube 3.

[0068] When releasing tube 2, Fig.12As shown, the distal end of the release tube 2 moves into the outer sheath 1, so that the proximal end of the self-expanding stent 4 is first released into the distal end of the outer sheath 1, as shown in FIG. Fig.13 As shown, the outer sheath 1 is withdrawn relative to the inner tube 3, and the self-expanding stent 4 is completely released into the blood vessel. Different from the traditional release tube withdrawal, which directly releases the stent into the blood vessel, the present invention uses the outer sheath to release the stent twice in steps, reducing the elastic force of the stent released from the tube, thereby inhibiting the stent from moving forward when released.

[0069] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A self-expanding stent system for bifurcated blood vessels, wherein the bifurcated blood vessels include mutually connected diseased blood vessels and non-diseased blood vessels connected to the diseased blood vessels, the self-expanding stent system includes a release tube, an inner tube, a self-expanding stent, a positioning guide wire and a guide guide wire, the release tube is sleeved outside the inner tube, the self-expanding stent is releasably received between the release tube and the distal end of the inner tube, the guide guide wire and the inner tube form an axial sliding fit, when used clinically, the guide guide wire extends into the diseased blood vessel, and the positioning guide wire extends into the non-diseased blood vessel, characterized in that An outer sheath is disposed outside the release tube, and a fixing piece is disposed at the distal end of the outer sheath. The fixing piece forms a sliding fit with the positioning guide wire, so that the positioning guide wire and the release tube form an angle.

2. The self-expanding stent system for bifurcated blood vessels according to claim 1, characterized in that: The outer sheath tube is coaxially arranged with the release tube and the inner tube.

3. The self-expanding stent system for bifurcated blood vessels according to claim 1, characterized in that: A support unit is fixedly arranged at the distal end of the inner tube, and the proximal end of the self-expanding stent is connected to the distal end of the support unit.

4. The self-expanding stent system for bifurcated blood vessels according to claim 1, characterized in that: The fixing piece is in a ring shape surrounded by wire.

5. The self-expanding stent system for bifurcated blood vessels according to claim 1, characterized in that: The fixing piece is tubular, and the distal end of the fixing piece does not exceed the distal end of the outer sheath.

6. The self-expanding stent system for bifurcated blood vessels according to claim 1, characterized in that: The fixing piece is an open slot, the opening size of the slot is smaller than the outer diameter of the positioning guide wire, and the distal end of the slot does not exceed the distal end of the outer sheath.

7. The self-expanding stent system for bifurcated blood vessels according to claim 1, characterized in that: The distance between the distal end of the fixing element and the distal end of the outer sheath is 0-5 cm.

8. The self-expanding stent system for bifurcated blood vessels according to claim 7, characterized in that: The distance between the distal end of the fixing element and the distal end of the outer sheath is 0-3 cm.

9. The self-expanding stent system for bifurcated blood vessels according to claim 7, characterized in that: The distance between the distal end of the fixing element and the distal end of the outer sheath is 3-5 cm.

10. The self-expanding stent system for bifurcated blood vessels according to claim 1, characterized in that: Before the self-expanding stent is released, the distance between the distal end of the outer sheath and the distal end of the self-expanding stent is less than the length of the self-expanding stent.

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