Embolic protection devices for intravascular use
The coaxial helical embolism protection device with a connecting ring and retract wire addresses manufacturing complexity and blood flow turbulence, improving thrombus capture and production efficiency.
Patent Information
- Application Number
- JP2025508846
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-08-17
- Filing Date
- 2023-03-10
- Publication Date
- 2025-08-07
AI Technical Summary
Existing embolism protection devices face challenges in manufacturing complexity, significant blood flow disturbances, and difficulty in capturing small thrombi, particularly due to the use of non-coaxial helical wires which are prone to deformation and turbulence.
An intravascular embolism protection device with a metal wire or strip having an elliptical or flat cross section, formed into a coaxial multi-turn helix or spiral, allowing it to return to a preset shape and featuring a connecting ring and retract wire for deployment and retrieval, with a fixation portion to secure it to the vessel wall.
Enhances thrombus capture capability, reduces blood flow turbulence, and simplifies manufacturing by using a coaxial helix design that maintains stable blood flow and minimizes production difficulties.
Smart Images
Figure 2025526157000001_ABST
Abstract
Description
[Technical Field]
[0001] FIELD OF THE INVENTION The present invention relates to medical devices, and more particularly to embolism protection devices for intravascular use. [Background technology]
[0002] The technology described in CN104736102A and patent US20080183206A1 by Batiste, Stanley are the only currently known technologies for constructing a vascular embolism protection device using a single wire. The basic principle of CN104736102A is to pre-set the shape of a superelastic alloy metal wire and deliver it through a hollow needle into the target vascular lumen. After insertion, the wire returns to its pre-set shape, stabilizes within the blood vessel, and captures the thrombus. The current patent and product information include the following two examples:
[0003] In this embodiment, a spiral line is formed in a blood vessel, with the axis of the spiral line perpendicular to the direction of blood flow. In this embodiment, if the gap in the spiral line is too small, the thrombus can be trapped, but the blood flow rate will be reduced. If the gap is too large, the thrombus will pass through the gap, and the purpose of trapping the thrombus will not be achieved.
[0004] In one embodiment, multiple helical wires made of a single metal wire are formed within a blood vessel, with the axes of these helical wires parallel to each other but different, and the axes are parallel to the direction of blood flow. This embodiment solves the problem of balancing blood flow rate and thrombus capture capability. However, to achieve this technical effect, a non-coaxial helical wire is used. Manufacturing a coaxial helical wire is more difficult because a thinner wire diameter is required to capture thrombi. However, a thinner wire diameter makes the metal wire more susceptible to deformation by blood flow, resulting in loss of capture capability. A non-coaxial helical wire also complicates mold formation during manufacturing and reduces the yield of heat setting. The Batiste and Stanley patent uses a coaxial helical wire. However, because its application environment is venous and the target thrombus size is relatively large, a thinner metal wire and a larger helical diameter can be used to achieve the desired effect. However, if the vessel wall is highly elastic, an intravascular embolism protection device will deform with the pulsation of the vessel wall, causing fluctuations in blood flow. Fluctuations in blood flow can cause localized turbulence, further increasing the likelihood of clot formation. Therefore, existing technologies require further improvement to reduce turbulence, capture smaller clots, and simplify processing. Summary of the Invention [Problem to be solved by the invention]
[0005] The present invention provides solutions to existing challenges in embolism protection devices, such as complex manufacturing processes, significant blood flow disturbances, and difficulty capturing small thrombi. To achieve these objectives, the present invention provides an intravascular embolism protection device consisting of a metal wire or strip with an oval or flat cross section, formed into a coaxial, multi-turn helix or spiral wire with a predictable shape. The single wire can be straight in a constrained state and return to a preset shape in a free state. Furthermore, the intravascular embolism protection device can be deployed into a tubular object and introduced into a target blood vessel through the tubular object. The elasticity of the material allows it to return to the preset shape, achieving the goal of capturing thrombi. The present invention also provides an intravascular embolism protection device consisting of three parts: an embolism protection device, a connecting ring, and a retract wire. The embolic protection device is a spiral wire made of flat superelastic alloy metal wire, and a connecting ring connects the embolic protection device to a retract wire. The retract wire is used to quickly withdraw the embolic protection device for intravascular use by pulling the retract wire if the device does not achieve the expected results or if problems occur after implantation. The present invention also provides an embolic protection device for intravascular use, which is a spiral wire made of flat superelastic alloy metal wire and includes a fixation portion. The fixation portion fixes the embolic protection device for intravascular use to the vessel wall by compressive stress between the metal wire and the blood vessel, and the diameter of the central capture portion is smaller than the smallest diameter of the target thrombus to be captured. [Effects of the Invention]
[0006] The beneficial effects of the present invention are as follows: Improved performance of intravascular embolic protection devices, increasing their ability to capture smaller clots. Improve the hemodynamic environment of intravascular embolic protection devices in the body, reducing the incidence of turbulence and further decreasing the probability of thrombus formation. In manufacturing, it reduces production difficulties and improves production efficiency of intravascular embolism protection devices. [Brief explanation of the drawings]
[0007] FIG. 1 is a structural diagram of an embodiment of the present invention. FIG. 2 is a structural diagram of another embodiment of the present invention. FIG. 3 is an axial view of a configuration of an embolism protection device for intravascular use implanted within a blood vessel. DETAILED DESCRIPTION OF THE INVENTION
[0008] The present invention relates to an intravascular embolism protection device, which is made of a metal wire or strip with an elliptical or flat cross section and pre-formed into a coaxial helix or spiral structure. The formed intravascular embolism protection device can be deployed into a tubular object and introduced into a target blood vessel through the tubular object. The elasticity of the material allows it to return to its pre-formed shape, achieving the goal of capturing thrombi. Because a coaxial helix wire can be easily manufactured, it has a smaller impact on the blood flow field than a non-coaxial helix wire, resulting in a more stable flow field and a smaller curvature in the capture area, ensuring capture performance.
[0009] A detailed description of the present invention is as follows: Referring to Figure 1, this is a structural diagram of an embodiment of the present invention. As shown in Figure 1, this embodiment of the present invention is a curve formed by winding a single wire. The embolism protection device 101 has the characteristics of a spiral wire made of a flat superelastic alloy metal wire, with the axis of the spiral wire forming an acute angle with the wide surface of the flat wire. This embodiment minimizes distortion of the final embolism protection device 101 and ensures that the metal wire returns to its original shape after passing through a long straight channel. Meanwhile, the width of the flat wire is larger than the wire thickness in the axial direction (usually 1.5 times or more the wire thickness), thereby minimizing deformation of the embolism protection device 101 when subjected to the impact of blood flow and avoiding blood flow disturbance due to deformation of the blood flow. Furthermore, the thin side of the flat wire applies greater local stress to the accumulated thrombus on the embolism protection device 101 under blood flow washing, thereby breaking the soft thrombus into smaller fragments and avoiding local thrombus blockage. The connecting ring 102 is preferably made of a biodegradable metallic material (e.g., magnesium alloy, iron alloy, etc.) or a biocompatible, non-degradable material (e.g., titanium alloy, stainless steel, etc.), and its main function is to connect the embolism protection device 101 to the retract wire 103. The connecting ring 102 remains in the vessel wall after implantation and undergoes endothelialization, with its endothelialization rate being greater than its degradation rate. The retract wire 103 is designed to allow for immediate withdrawal of the intravascular embolism protection device by pulling the retract wire 103 if the device does not achieve the expected results or if problems occur after implantation. The retract wire 103 is made of absorbable thread that can withstand tensile force.
[0010] Figure 2 shows the structure of another embodiment of the present invention. The embolism protection device 105 is made of a single superelastic alloy wire, characterized by a spiral wire made of flat superelastic alloy wire. The anchoring portion 107 secures the intravascular embolism protection device to the vessel wall through compressive stress between the wire and the blood vessel, and the diameter of the central capture portion 108 is smaller than the minimum diameter of the target thrombus to be captured. Compared to Example 1, this embodiment has the advantage of preventing foreign bodies from straddling the vessel wall after implantation. While the foreign bodies in the previous embodiment eventually decompose and become endothelialized, they remain. Figure 3 shows an axial view of the shape of the intravascular embolism protection device implanted in a blood vessel, with a central coaxial cavity whose diameter should be smaller than the minimum diameter of the target thrombus to be captured. It can also be seen that the distribution of the embolism protection device is spread around the axis and more uniformly spaced. Finite element analysis was used to simulate the effects of different cross-sectional shapes of the intravascular embolism protection device on the pressure on the vessel wall and blood flow. The simulation was based on the vessel wall in systole (high pressure) with an inner diameter 10% smaller than the outer diameter of the endovascular embolic protection device, a systolic pressure of 120 mmHg, and a diastolic pressure of 80 mmHg. The pressure and velocity changes of the major branch arteries (carotid, cerebral) were used as boundary conditions, and the results are as follows: For an intravascular embolic protection device with a circular cross-section of 0.25 mm in diameter, the maximum instantaneous pressure on the vessel wall is 52.3 ± 7.8 KPa. The local pressure difference across an intravascular embolic protection device with a circular cross-section of 0.25 mm diameter is approximately 7.5 mmHg. For an intravascular embolic protection device with an elliptical cross section, with a major axis of 0.25 mm and a minor axis of 0.12 mm, the maximum instantaneous pressure on the vessel wall is 27.6 ± 4.0 KPa. The local pressure difference across the endovascular embolic protection device with an elliptical cross-section was approximately 5.7 mmHg. Compared with a circular cross-section, an elliptical cross-section reduces the local pressure on the vessel wall, making it less likely to cause vessel wall thickening. Meanwhile, the blood flow pressure drop through an elliptical cross-section is much lower than that of a circular cross-section, better maintaining the blood flow pressure and velocity at different cross-sections and minimizing the impact on local blood flow. Coaxial and non-coaxial spiral wire devices did not exhibit trailing blood flow vectors (i.e., local vortex flow) in the blood flow field distribution during endovascular thrombus occlusion. The differences in maximum and minimum local blood flow velocity between the coaxial and non-coaxial spiral wire devices during systole were 0.67 m / s and 1.32 m / s, respectively. The maximum velocity was at the central capture site, and the minimum velocity was at the trailing end of the blood flow through the endovascular embolic protection device. Therefore, the coaxial helical wire intravascular embolism protection device has less impact on local blood flow than non-coaxial helical wire devices and is more compatible with the natural human blood flow.
[0011] Those skilled in the art can make other modifications based on the creative spirit of the present invention, and these various modifications derived based on the creative spirit of the present invention should fall within the protection scope of the present invention.
Claims
1. An embolism protection device for intravascular use, characterized in that a metal wire or strip of oval or flat cross section is formed into a coaxial, multi-turn helix or spiral configuration.
2. 10. The device of claim 1, wherein the metal wire is straight in a constrained state and can return to a preset shape in a free state.
3. 3. The device according to claim 1 or 2, wherein the cross section of the metal wire is flat or elliptical.
4. 10. The apparatus of claim 1, wherein the embolism protection device is deployed into a tubular object, introduced through the tubular object into a target blood vessel, and then returns to a preset shape to capture thrombi.
5. 1. An embolism protection device for intravascular use, comprising: - A spiral wire made of a flat superelastic alloy metal wire, a connecting ring connecting the embolism protection device to a retract wire; and A retract wire for withdrawing the embolism protection device from the vessel by pulling the retract wire if the expected results are not achieved or if problems arise after deployment.
6. 6. The device of claim 5, wherein the connecting ring is endothelialized, the endothelialization rate being greater than the degradation rate.
7. 1. An embolism protection device for intravascular use, comprising: A spiral wire made of a flat superelastic alloy metal wire, the spiral wire including a fixing portion, The device, characterized in that the fixing portion generates compressive stress between the metal wire and the blood vessel, thereby fixing the embolism protection device to the blood vessel wall within the blood vessel.