A vascular intervention micro-device and a preparation method thereof

Abstract

The present invention relates to the technical field of medical devices, and particularly relates to a vascular intervention micro-device and a preparation method thereof. The vascular intervention micro-device includes: a driving wire and an elastic matrix; the driving wire is arranged inside the elastic matrix, the direction of the driving wire is along the axial direction of the elastic matrix, and the driving wire is arranged with a radial offset inside the elastic matrix. The driving wire is a shape memory alloy in a spiral shape; a pressure increasing channel is arranged inside the elastic matrix, the pressure increasing channel is along the axial direction of the elastic matrix and does not overlap with the driving wire, and is used for introducing a liquid to change the stiffness of the elastic matrix. Through the cooperation of the driving wire and the pressure increasing channel inside the elastic matrix, the intervention micro-device generates different bending angles at different vascular bifurcations, realizing the functions of active guidance and thrombus capture of the intervention micro-device.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly to a vascular intervention micro-device and a preparation method thereof. Background Art

[0002] Disclosing the information of this background art section is only intended to enhance the overall understanding of the present invention, and is not necessarily regarded as an admission or an implication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] Interventional surgery, as a method gradually developed for cardiovascular and cerebrovascular diseases, can overcome the drawbacks of traditional surgeries. It only requires local anesthesia, and then a small incision is made for catheter insertion. Guided by imaging equipment, it is moved to the diseased area for subsequent treatment. This surgery has the advantages of no need for open surgery, small trauma, fast recovery, and good effect, and is the development trend of future medicine. Cerebrovascular interventional mechanical thrombectomy plays an important role in the treatment of ischemic stroke patients.

[0004] Existing cerebrovascular interventional mechanical thrombectomy systems generally include four parts: a balloon catheter, a microcatheter, a guide wire, and a thrombectomy device. The system design and operation are relatively complex, and are restricted by the millimeter-level radial size constraint of the cerebral blood vessels. The head of traditional catheter-based interventional devices cannot bend independently, and can only be guided by relying on the friction between the catheter and the blood vessel wall, with low efficiency and a risk of scratching the blood vessel. In the existing active guide wire catheter designs, common driving methods include shape memory alloy spring driving, electrode driving, magnetic driving, etc. However, the application of interventional guide wires designed based on the above driving methods is also limited to cerebral blood vessels with a larger diameter. For cerebral blood vessels with a diameter of less than 2 millimeters, these devices often have difficulty achieving effective guidance and thrombectomy functions due to the lack of active manipulation ability or excessive radial size.

[0005] Cerebrovascular mechanical thrombectomy techniques can be mainly divided into stent-based thrombectomy and aspiration thrombectomy. Stent-based thrombectomy is to guide a microcatheter to the distal end of a cerebral thrombus through a microguide wire, then remove the microguide wire, and then place a stent into the blood vessel along the microcatheter to grab the thrombus, and finally take out the device and the thrombus together. Aspiration thrombectomy directly uses the negative pressure aspiration of the microcatheter to extract the thrombus after guiding the microcatheter to the proximal end of the cerebral thrombus through a microguide wire. In addition, there is also a stent combined with negative pressure aspiration thrombectomy technique, that is, negative pressure aspiration is started while using a stent-based thrombectomy device for thrombus removal.

[0006] However, a large number of clinical practices have shown that the rate of improvement (complete without sequelae, with mild dysfunction or mild disability) within 90 days after these mechanical thrombectomy procedures for patients is only 25% - 47%, while most patients have moderate, severe, or serious disabilities or even die after the operation. This is not only related to the complex, narrow, and fragile internal environment of the cerebral blood vessels, but also related to the system design and cumbersome operation process of the micro-devices for cerebral vascular intervention (mainly including guide wires and thrombectomy devices). Moreover, most cerebral vascular intervention surgeries are directly performed by doctors using cerebral vascular intervention equipment. The complex, narrow, and fragile cerebral vascular environment poses higher requirements for the miniaturization, safety, efficiency, and maneuverability of cerebral vascular intervention equipment. Summary of the Invention

[0007] Aiming at the deficiencies of the existing technology, the purpose of the embodiments of the present invention is to provide a micro-device for vascular intervention, aiming to achieve two-dimensional and three-dimensional reconstruction of the one-dimensional intervention micro-device to meet the active guiding requirements of the intervention micro-device at the vascular bifurcation and the thrombus capture requirements at the lesion during cerebral vascular intervention surgery.

[0008] To achieve the above purpose, the embodiments of the present invention provide the following technical solutions:

[0009] A micro-device for vascular intervention, comprising: a driving wire and an elastic matrix; the driving wire is arranged inside the elastic matrix, the direction of the driving wire is along the axial direction of the elastic matrix, and the driving wire is arranged with a radial offset inside the elastic matrix. The driving wire is made of shape memory alloy and is helical; a pressure-increasing channel is arranged inside the elastic matrix, the pressure-increasing channel is along the axial direction of the elastic matrix and does not overlap with the driving wire, and is used for introducing liquid to change the stiffness of the elastic matrix.

[0010] Preferably, the pressure-increasing channel is arranged at the center of the elastic matrix.

[0011] Preferably, the pressure-increasing channel is helical.

[0012] Preferably, the elastic matrix is made of TPU material.

[0013] Preferably, both ends of the elastic matrix are a base end and a tip end respectively. The pressure-increasing channel opens at the base end of the elastic matrix and is closed at the tip end of the elastic matrix.

[0014] Preferably, it further comprises an intervention catheter, and the intervention catheter is connected to the base end of the elastic matrix.

[0015] Preferably, the intervention catheter and the base end of the elastic matrix are assembled and fixed by bonding.

[0016] The embodiment of the present invention also provides a preparation method of the above-mentioned vascular intervention micro-device, including: performing three-dimensional braiding on the drive wire to prepare a silica gel wire; injecting and molding the braided drive wire and the silica gel wire in an elastic matrix; pulling out the silica gel wire from the elastic matrix to form a pressure-increasing channel.

[0017] Preferably, before performing three-dimensional braiding on the drive wire, pre-treatment is carried out. The drive wire is stretched at room temperature, and after completing the detwinning process, it is unloaded.

[0018] Preferably, the drive wire injected into the elastic matrix is arranged in a biased manner.

[0019] One or more technical solutions provided in the embodiment of the present invention have at least the following technical effects or advantages:

[0020] 1. In the vascular intervention micro-device proposed by the present invention, a shape memory alloy drive wire that is three-dimensionally braided is arranged in a biased manner in an elastic matrix as a driver. By changing the bias distance and braiding method of the control wire, the deformation mode (such as bending, torsion, etc.) and deformation degree of the intervention micro-device are adjusted. By controlling the input current and cooling rate of the shape memory alloy thin wire, continuous control of the deformation of the intervention micro-device can be achieved. At the same time, by controlling the inflow and outflow of physiological saline in the pressure-increasing channel, the overall stiffness of the intervention micro-device is adjusted. Therefore, the present invention drives the elastic matrix to generate a bending deformation that matches the stiffness adjusted by the pressure-increasing channel by controlling the current input to the drive wire. Through the cooperation of the drive wire and the pressure-increasing channel in the elastic matrix, the intervention micro-device generates different bending angles at different vascular bifurcations, realizing the functions of active guidance and thrombus capture of the intervention micro-device.

[0021] 2. The vascular intervention micro-device of the present invention has a simple structure, is easy to process and manufacture, and has high action execution efficiency. The vascular intervention micro-device adopts an integrated design and has certain advantages in miniaturization. Its structural dimensions can be reasonably designed according to application requirements, and it has a broad application prospect in the field of interventional surgery.

[0022] The advantages of the additional aspects of the present invention will be given in the following description, some of which will become obvious from the following description, or will be understood through the practice of the present invention.

[0023] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following preferred embodiments are specifically illustrated in conjunction with the accompanying drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The specification drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0025] Figure 1Schematic diagram of the structure of the vascular intervention micro-device of the present invention

[0026] Figure 2 Perspective view of the matrix of the vascular intervention micro-device of the present invention

[0027] Figure 3 Schematic diagram of the structure of the active catheter containing the vascular intervention micro-device of the present invention

[0028] Figure 4 Schematic diagram of active guidance-linear feed

[0029] Figure 5 Schematic diagram of active guidance-obtuse angle turning

[0030] Figure 6 Schematic diagram of active guidance-right angle turning

[0031] Figure 7 Schematic diagram of active guidance-acute angle turning

[0032] Figure 8 Schematic diagram of the thrombus capture process

[0033] In the figure: 1. Driving wire; 2. Elastic matrix; 201. Boosting channel; 202. SMA channel; 203. Base end; 204. Tip; 3. Intervention catheter; 4. Bifurcated blood vessel; 5. Thrombus; 6. Diseased blood vessel;

[0034] The distances or dimensions between each part are exaggerated for showing the positions of each part, and the schematic diagram is only for illustration purposes. Detailed implementation manners

[0035] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0036] It should be noted that the terms used herein are only for describing the specific implementation manners and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the present invention otherwise clearly indicates, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0037] In order to solve the above problems in the background technology, the present invention proposes a design scheme of a vascular intervention micro-device based on a shape memory alloy (SMA for short) to drive a soft elastic matrix to generate two-dimensional and three-dimensional reconstruction, especially applied to cardiovascular and cerebrovascular diseases, and can realize the functions of active guidance and thrombus capture during the thrombus removal process.

[0038] Example 1

[0039] As Figure 1 - As Figure 3 shown, the vascular interventional micro-device includes: a driving wire 1 and an elastic matrix 2; the driving wire 1 is disposed within the elastic matrix 2, the direction of the driving wire 1 is along the axial direction of the elastic matrix 2, and the driving wire 1 is disposed with a radial offset within the elastic matrix 2. The driving wire 1 is a shape memory alloy in a spiral shape; a pressure increasing channel 201 is disposed within the elastic matrix 2. The pressure increasing channel 201 is along the axial direction of the elastic matrix 2 and does not overlap with the driving wire 1, and is used for introducing a liquid to change the stiffness of the elastic matrix 2.

[0040] The driving wire 1 is made of nickel-titanium shape memory alloy. As a typical temperature-controlled intelligent material, shape memory alloy (SMA) is naturally suitable for the driving and control of the elastic matrix 2 of super-elastic soft materials (such as PDMS) due to its high power density, super-elasticity and shape memory characteristics; in addition, the constitutive model of SMA has been relatively mature, and some effective control methods have also been formed.

[0041] As an alloy with "memory", SMA can undergo phase transformations among twinned martensite phase, detwinned martensite phase and austenite phase under the action of external stress and temperature, and macroscopic deformation occurs during the phase transformation process, thereby generating a driving force for driving the elastic matrix 2. Therefore, designing an active guide wire with both active guiding and thrombus capture functions based on shape memory alloy has important value and practical significance for the clinical application requirements of cerebrovascular interventional mechanical thrombectomy surgery.

[0042] The present invention uses Joule heat to drive the shape memory alloy to undergo phase transformation and deformation under the constraint of the super-elastic matrix 2. After the driving wire 1 is energized, the temperature rises above the austenite phase transformation completion temperature, and the SMA undergoes a complete austenite phase transformation. The driving wire 1 changes from soft to hard, that is, the Young's modulus becomes larger, and the driving wire 1 shortens along the radial direction. The driving wire 1 woven in a spiral shape can drive the elastic matrix 2 to undergo the largest bending-torsion coupling deformation; after power-off, when the temperature of the driving wire 1 drops below the martensite phase transformation completion temperature, the SMA undergoes a complete martensite phase transformation, the SMA changes from hard to soft, that is, the Young's modulus becomes smaller, and the elastically deformed matrix 2 that has undergone bending-torsion coupling deformation partially recovers its initial shape, and the strain of the driving wire 1 embedded in the elastic matrix 2 also partially recovers.

[0043] The elastic matrix is made of TPU (thermoplastic polyurethane elastomer rubber) material. As a super-elastic matrix, TPU can ensure the flexible contact between the interventional micro-device and the cerebrovascular wall to avoid damage to the cerebrovascular wall. At the same time, the radial dimension of the shape memory alloy wire can reach a minimum of 20 microns, providing a huge space for further miniaturization of the present invention.

[0044] Facing the complex and narrow cerebrovascular environment, the ratio of the length dimension to the radial dimension of the interventional micro-device of the present invention is as high as 100, which makes the stiffness of the elastic matrix 2 in the directions of tension, compression, bending, torsion, etc. often very weak and difficult to maintain a stable configuration. As Figures 4-7 shown, when it is required that the interventional micro-device bends in different directions at the bifurcation of the bifurcated blood vessel to achieve the guiding function, the stiffness of the interventional micro-device needs to be in different states. In order to moderately increase and regulate the stiffness of the micro-device, the present invention adopts a hydraulic drive mode, and designs a micro-channel (i.e., the pressure-boosting channel 201) with a specific spatial configuration (such as a spiral shape) along the length direction of the micro-device. The micro-channel opens at the base end 203 connected to the interventional catheter 3 for controlling the entry and exit of physiological saline; while it is closed near the tip 204 of the micro-device to achieve the pressure-boosting control of physiological saline on the micro-channel, and the stiffness of the interventional micro-device is adjusted by injecting physiological saline into the pressure-boosting channel 201. Specifically, the stiffness of the interventional micro-device should decrease as the rotation angle increases.

[0045] The vascular interventional micro-device proposed by the present invention is provided with a three-dimensionally braided shape memory alloy drive wire 1 offset in the elastic matrix 2 as a driver. By changing the offset distance and braiding method of the control wire, the deformation mode (such as bending, torsion, etc.) and deformation degree of the interventional micro-device are further adjusted. By controlling the input current and cooling rate of the shape memory alloy filaments, continuous control of the deformation of the interventional micro-device can be achieved. At the same time, the overall stiffness of the interventional micro-device is adjusted by controlling the entry and exit of physiological saline in the pressure-boosting channel 201.

[0046] Therefore, the present invention drives the elastic matrix 2 to generate a bending deformation matching the stiffness adjusted by the pressure-boosting channel 201 by controlling the current input to the drive wire 1. Through the cooperation of the drive wire 1 in the elastic matrix 2 and the pressure-boosting channel 201, the interventional micro-device generates different bending angles at different blood vessel bifurcations, realizing the active guiding and thrombus capturing functions of the interventional micro-device.

[0047] The drive wire 1 can be arranged in various forms in the elastic matrix 2. To achieve the active guiding and thrombus capturing functions proposed in the present application, the drive wire 1 is three-dimensionally braided in a spiral shape.

[0048] As Figure 2 shown, the two ends of the elastic matrix 2 are respectively a base end 203 and a tip 204, the pressure-boosting channel 201 opens at the base end 203 of the elastic matrix 2, and the pressure-boosting channel 201 is closed at the tip 204 of the elastic matrix 2. As Figure 3As shown in the figure, the active catheter can be obtained by assembling the elastic matrix 2 of the interventional micro-device and the interventional catheter 3 at the proximal end 203. In this embodiment, glue bonding is used for assembly and fixation, but this method is not limited thereto.

[0049] The thrombus capture process is as follows Figure 8 As shown in the figure, assuming that there is a thrombus 5 in the diseased blood vessel 6, as Figure 8 (a), after guiding, the tip 204 of the elastic matrix 2 of the interventional micro-device reaches the proximal end of the thrombus 5 in the diseased blood vessel 6; then continue to feed forward, as Figure 8 (b), the tip 204 of the elastic matrix 2 of the interventional micro-device penetrates the thrombus 5 in the diseased blood vessel 6 and reaches the distal end of the thrombus 5; as Figure 8 (c), the drive wire 1 in the interventional micro-device undergoes a phase change under electrothermal excitation, driving the elastic matrix 2 to perform three-dimensional reconstruction to achieve the capture of the thrombus, and then taking it out to complete the thrombus removal process.

[0050] Embodiment 2

[0051] For the vascular interventional micro-device proposed in Embodiment 1, this embodiment provides a typical manufacturing method, but the actual operation process is not limited to this method.

[0052] A cerebrovascular interventional micro-device with both active guiding and thrombus capture functions should use materials with biocompatibility and should not cause damage to the human body. Therefore, the manufacturing method proposed in the present invention uses nickel-titanium shape memory alloy filaments as the material for the drive wire 1. Considering various factors, the interventional micro-device proposed in the present invention uses TPU as the material for the elastic matrix 2, but is not limited to this material. For example, it can also be silicone, PDMS (polydimethylsiloxane), etc.

[0053] The shape memory alloy filaments are pre-treated. First, the shape memory alloy filaments are stretched at room temperature (about 25 °C), and after the detwinning process is completed, they are unloaded. At this time, about 8% of the residual strain is retained in the shape memory alloy filaments.

[0054] The pre-treated shape memory alloy filaments are three-dimensionally braided. Meanwhile, a super-elastic silicone wire with a lower Young's modulus is manufactured by the wire drawing method. Then, the braided shape memory alloy wire and the super-elastic silicone wire are placed in a mold, and liquid TPU is injected into the mold. After it cures, the super-elastic silicone wire is slowly pulled out from the elastic matrix 2 to form a pressurization channel 201 in the elastic matrix 2. The super-elastic silicone wire is arranged along the length direction at the central position of the elastic matrix 2, and the driving wire 1 is arranged along the length direction inside the elastic matrix 2 in a biased manner. Since the driving wire 1 injected into the elastic matrix 2 is arranged in a biased manner, it can drive the elastic matrix 2 to bend and twist. After coupling, a helical deformation can be generated to complete the capture of the thrombus. At the same time, the stiffness of the interventional micro-device can be adjusted by the inflow and outflow of physiological saline in the micro-channel, and then the deformation degree of the elastic matrix 2 can be adjusted to achieve the guiding function.

[0055] The three-dimensionally braided driving wire 1 is embedded in the elastic matrix 2 in a biased manner. If the driving wire 1 is peeled off from the elastic matrix 2, an SMA channel 202 will be left in the elastic matrix 2. During the manufacturing process, gaps at the contact position between the driving wire 1 and the elastic matrix 2 should be avoided as much as possible to prevent relative sliding between the driving wire 1 and the elastic matrix 2, so as to ensure a better deformation effect.

[0056] When the interventional micro-device works, at the initial low temperature, the driving wire 1 is in the detwinned martensite phase state. Under the excitation of Joule heat, the driving wire 1 undergoes an austenite phase transformation. The austenite phase at high temperature can drive the elastic matrix 2 to deform. At the same time, the elastic matrix 2 can store a certain amount of elastic potential energy. After stopping heating, the driving wire 1 cools from high temperature to low temperature, and its phase state changes from the austenite phase to the martensite phase. Due to the constraint of the elastic matrix 2, only a part of its initial shape can be restored.

[0057] Although the specific implementation manners of the present invention are described above in conjunction with the accompanying drawings, it is not a limitation to the protection scope of the present invention. Those skilled in the art should understand that based on the technical solutions of the present invention, various modifications or deformations that can be made by those skilled in the art without creative efforts are still within the protection scope of the present invention.

Claims

1. A vascular interventional micro-device, characterized in that, Comprising: A drive wire and an elastic matrix; The drive wire is disposed within the elastic matrix, the direction of the drive wire is along the axial direction of the elastic matrix, and the drive wire is disposed with a radial offset within the elastic matrix. The drive wire is a shape memory alloy and is helical; A pressure boosting channel is disposed within the elastic matrix. The pressure boosting channel is along the axial direction of the elastic matrix and does not overlap with the drive wire, and is used for introducing a liquid to change the stiffness of the elastic matrix.

2. The vascular intervention micro-device according to claim 1, wherein, The pressure boosting channel is disposed at the center of the elastic matrix.

3. The vascular intervention micro-device according to claim 1, characterized in that, The pressure boosting channel is helical.

4. The vascular intervention micro-device according to claim 1, wherein, The elastic matrix is made of a TPU material.

5. The vascular intervention micro-device according to claim 1, wherein Both ends of the elastic matrix are respectively a base end and a tip end. The pressure boosting channel is open at the base end of the elastic matrix and is closed at the tip end of the elastic matrix.

6. The vascular intervention micro-device according to claim 5, characterized in that, An interventional catheter is further included, and the interventional catheter is connected to the base end of the elastic matrix.

7. The vascular intervention micro-device according to claim 6, wherein The interventional catheter and the base end of the elastic matrix are assembled and fixed by an adhesive bonding method.

8. The preparation method of the vascular intervention micro-device according to any one of claims 1-7, characterized in that, Comprising: Three-dimensionally braid the drive wire to prepare a silica gel wire; Inject the braided drive wire and the silica gel wire into the elastic matrix; Pull out the silica gel wire from within the elastic matrix to form a pressure boosting channel.

9. The preparation method of the vascular intervention micro-device according to claim 8, characterized in that, Perform pre-treatment before three-dimensionally braiding the drive wire. Stretch the drive wire at room temperature, and unload it after completing the detwinning process.

10. The preparation method of the vascular intervention micro-device according to claim 8, characterized in that, The drive wire injected into the elastic matrix is disposed with a bias.

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