A peripheral vein protection stent

Abstract

The present invention discloses a peripheral venous protection stent, comprising a rotary cutting element, an ejection tube, an inner tube, a cannula funnel, a loading sheath, and an outer sheath tube, characterized in that: the rotary cutting element comprises a grinding section, a straight section, and a funnel section; the proximal end of the rotary cutting element is closed on the ejection tube, the rotary cutting element is a closed mesh cage structure, and the distal end of the rotary cutting element is a circular ring and extends to the straight section to form a closed design. The cannula funnel can be used alone or in conjunction with the rotary cutting element. The peripheral venous protection stent can avoid the risk of pulmonary embolism caused by thrombus production due to long-term catheterization during central venous catheterization via peripheral venous puncture; at the same time, it can avoid the risk of thrombus detachment during other interventional surgeries such as peripheral vascular thrombectomy and peripheral stent implantation.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical devices and relates to a peripheral stent combined with a PICC central venous catheter, and in particular to a peripheral venous protection stent for preventing thrombus shedding. Background Art

[0002] PICC placement is a peripherally inserted central venous catheter (CVC). It involves inserting a catheter through a peripheral arm vein (primarily the basilic or cephalic vein), inserting the catheter into the superior vena cava and reaching the upper edge of the right atrium. The catheter then delivers the appropriate chemotherapy drug. The primary purpose of PICC placement is to prevent direct contact between chemotherapy drugs and the arm vein, which can cause chemical irritation. Furthermore, the rapid blood return in large veins can quickly dilute chemotherapy drugs and prevent vascular irritation. Therefore, PICC placement can effectively protect upper extremity veins, reduce the incidence of phlebitis, alleviate pain, and improve patients' quality of life.

[0003] However, in the widespread and successful practice of PICC catheterization, the formation of thrombosis on the outer wall of the catheter due to prolonged placement remains an unresolved issue. Generally, 50% of patients develop thrombosis on the catheter surface, and among these 50% of patients, 60% of the catheters are blocked by thrombosis. Currently, the usual response to PICC catheter thrombosis is to undergo thrombolysis one week before extubation, but this still carries a high risk of thrombus dislodgement and pulmonary embolism. Therefore, it is necessary to eliminate the risk of thrombosis dislodgement during PICC extubation as simply as possible through minimally invasive interventions.

[0004] Similarly, in other peripheral interventional procedures, such as peripheral vascular thrombectomy and peripheral stent implantation, there is also the possibility of rapid thrombus formation and detachment, and simple interventional methods are also needed to eliminate the risk. Summary of the Invention

[0005] The present invention aims to overcome the shortcomings of the prior art by providing a peripheral venous stent. This device addresses the problem of thrombus formation and detachment on the device surface during various peripheral venous interventional procedures, particularly central venous catheterization, leading to proximal vascular obstruction and even pulmonary embolism. During use, the stent is inserted through an introducer sheath into an outer sheath tube and positioned distally at a first predetermined location on the central venous catheter (typically the superior edge of the right atrium or within the right atrium). The cannula funnel is then released from the outer sheath and continues distally. During this process, the central venous catheter slides along the smooth inner wall of the funnel into its lumen, thereby aligning the two devices. After determining catheter thrombosis based on angiography, the cannula funnel is selectively used alone or in conjunction with the rotary cutting element to perform rotary cutting. The device is then advanced distally along the central venous catheter to the target vessel (hereinafter, the brachiocephalic vein and subclavian vein are used as examples of target vessels for central venous catheterization). During this process, any thrombus encountered is scraped and collected. After scraping, the rotary cutting element and cannula funnel are pulled back into the outer sheath. Vacuum suction is then used to trap any thrombi that have fallen off the surface of the instrument, preventing them from drifting into the heart or lungs. The central venous catheter is removed from the body, and after ultrasound or other equipment confirms the absence of drifting thrombi, the outer sheath is removed.

[0006] To achieve the above-mentioned purpose, the technical solution of the present invention is to provide a peripheral venous protection stent, comprising a rotary cutting element 1, an ejection tube 2, an inner tube 3, a cannula funnel 4, a loading sheath, and an outer sheath tube. The outer sheath tube is provided by the hospital, and its specific dimensions (inner and outer diameters, whether it contains a reinforcement layer, length, etc.) can be determined by the clinician, and this stent is compatible with all of them.

[0007] Furthermore, the outer sheath has both the function of delivering the stent and suctioning. When the amount of thrombus is large, a large-caliber sheath can be selected for auxiliary suction to capture the thrombus.

[0008] Furthermore, the rotary cutting element can be presented as a cutting stent, with any cutting method, including but not limited to multiple ribs extending from the proximal end to form a straight section 5, a funnel section 6, and a laparotomy section 7; the proximal end 8 of the rotary cutting element is closed on the ejection tube, and the two ends are closed in a mesh cage structure. It can also be presented as a braided stent, and the mesh cage structure is described below as a preferred embodiment. The rotary cutting element is cut from suitable materials including but not limited to nickel-titanium alloy tubes, cobalt-chromium alloy tubes, and polymer tubes with shape memory functions. The relative positions of the cannula funnel, rotary cutting element, and outer sheath tube are changed to form four configurations corresponding to different stages of use. The distal end of the rotary cutting element is designed with a special cutting ring 9, whose functions are: 1. The ring accommodates the inner tube in the first configuration (complete release), the second configuration (only releases the sleeve funnel) and the fourth configuration (complete compression); 2. When changing from the second configuration to the third configuration (matching state), that is, when the sleeve funnel is withdrawn through the ring, the curled edge of the funnel is flattened and stretched to the distal end by the cutting ring and then compressed, so that it can smoothly enter the interior of the rotary cutting element; 3. When grabbing the thrombus forward along the PICC catheter in the third configuration, the ring scrapes the outer wall of the PICC catheter to cause the attached thrombus to fall off.

[0009] Furthermore, the rotary cutting element has a straight section and a funnel section. The straight section has good support and is close to the inner wall of the blood vessel to scrape the thrombus, while forming a larger inner cavity to accommodate the captured thrombus; the funnel section is composed of a number of independent supporting ribs, which has stronger support. In the third configuration, it cooperates with the cannula funnel to form a semi-enclosed space, which holds the thrombus while allowing blood to flow through the mesh.

[0010] Furthermore, the inner tube and the sleeve funnel are integrally formed, the proximal end of the sleeve funnel is connected to the distal end of the inner tube, and has a hollow inner cavity to accommodate the passage of a central venous catheter, and the inner tube passes through the distal cutting ring of the stent and the inner cavity of the ejection tube and extends therein.

[0011] Furthermore, the proximal end of the rotary cutting element's funnel segment is secured to an ejector tube, enabling release. The ejector tube can be implemented in a variety of forms, including but not limited to polymer tubing, metal tubing, spring tubing, braided mesh tubing, coil tubing, etc. The bracket and push rod can be connected in a variety of ways, including but not limited to riveting, welding, welding, mortise and tenon joints, etc. Stainless steel spring tubing is preferred, using a riveting and welding process.

[0012] Furthermore, the proximal end of the funnel section of the rotary cutting element is fixed to the distal end of the stainless steel spring tube by riveting, and the proximal end of the spring tube is connected to the rotating component in the operating handle. When the stent is pushed forward in the third configuration, the rotation of the rotating component drives the stent to rotate to form the effect of rotary cutting of the thrombus.

[0013] Furthermore, the rotary cutting element has a rotary atherectomy segment, which is composed of several ribs with specific curvatures, with the distal end converging into a cutting ring. After the rotary cutting element is released, it pushes forward and rotates, acting as a blade to break up the blood clots blocking the blood vessel around the PICC catheter.

[0014] Furthermore, when the rotary cutting element - ejector tube rotates and advances along the PICC catheter, if the connection between the straight section and the funnel section is a smooth surface (such as Figure 3 and Figure 12 The rotary cutting element part shown in FIG), because the sleeve funnel - inner tube has a self-lubricating PTFE material, it can be relatively stationary; if the connection has a barb 11 (such as Figure 7 、 Figure 8 and Figure 9 In the third configuration, the funnel flange 10 is restrained by the barbs, allowing the cannula funnel—the inner tube—to rotate with the bracket. This coordinated rotation can also be controlled by a corresponding component on the operating handle. The barbs 11 are typically cut simultaneously with the main body of the peeling element and heat-set using a special mold. Alternatively, they can be pre-fabricated and welded to the joint.

[0015] Furthermore, after reaching the first predetermined position, the stent can be repeatedly released and recovered in the second configuration, and the control wire can be adjusted in conjunction with the operating handle to find the optimal release position and release angle, so as to facilitate the PICC catheter to enter the inner cavity of the sheath funnel - inner tube.

[0016] Furthermore, the curling edge 10 of the sleeve funnel is achieved by heat setting the reinforcing ribs pre-embedded in the polytetrafluoroethylene layer.

[0017] Furthermore, the proximal end of the ejection tube is connected to the operating handle.

[0018] Furthermore, a control wire is pre-embedded in the polytetrafluoroethylene layer of the sleeve funnel, and the opening angle of the sleeve funnel after release is adjusted by the control wire. The control wire extends from the distal end of the sleeve funnel through the inner tube to the operating handle at the proximal end, and the operating handle contains a corresponding control element.

[0019] In order to match the above functions, the sleeve funnel can be made of a self-lubricating material such as PTFE, LDPE, PEEK, etc., and PTFE is preferred in this patent. The sleeve funnel has several supporting ribs to support its shape and form a curling edge 10 structure, such as Figure 5 In order to form the open funnel and the curling edge 10, the support ribs are usually made of a material with shape memory function, such as nickel-titanium alloy, and are heat-set into the desired shape during the manufacturing process.

[0020] Furthermore, the cannula funnel has a fine mesh structure to trap the thrombus without hindering blood flow, such as Figure 6 If the cannula funnel and inner tube are made of PTFE filaments through weaving, the mesh can be naturally formed during the weaving process by adjusting the weaving parameters. If the cannula funnel and inner tube are made of PTFE tubing through stretching, molding, etc., the mesh can be cut using a tool. The mesh size is less than 3 mm, typically less than 1 mm, and can also be customized to meet special needs.

[0021] Furthermore, the stent and / or components such as the tube can be developed under ultrasound. The development principle includes but is not limited to the tube wall containing ultrasound contrast agents, microporous bubbles and other ultrasound-developable materials, or the specific components have a rough surface to form high ultrasound reflection performance.

[0022] Furthermore, the access route and cooperation method of the protective stent in conjunction with central venous catheterization are usually through the femoral vein and iliac vein, released in the right atrium or the upper edge of the right atrium, and pushed over the brachiocephalic vein or subclavian vein. When released, the distal end of the central venous catheter contacts the inner wall of the cannula funnel, and is introduced into the inner cavity of the inner tube as the funnel is pushed forward. Due to the higher radial support force and excellent compliance of the straight section of the rotary cutting element, it is guaranteed that the thrombus will not escape through the gap. After the central vein is withdrawn, the stent can be withdrawn only after it is checked by imaging equipment. During the withdrawal, the stent is pulled back into the outer sheath. During the pulling back process, the rotary cutting element and the mesh of the cannula funnel contract and forcefully squeeze the thrombus, turning it into harmless debris with a diameter of less than 0.3 mm, and bringing part of the thrombus into the catheter through the stent, achieving perfect treatment of the thrombus. If necessary, the doctor can choose a larger caliber sheath and perform suction when withdrawing the stent to assist in the removal of the thrombus.

[0023] Compared with the existing technology, the present invention has the following advantages: (1) It can avoid the risk of pulmonary embolism caused by thrombosis during long-term central venous catheterization via peripheral venous puncture. (2) It can avoid the risk of thrombus dislodgement during interventional procedures such as peripheral vascular thrombectomy or peripheral stent implantation. (3) The guidewire-free design simplifies the operation process and is compatible with more different types of interventional devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The features and advantages of the present invention will become more apparent from the following detailed description of embodiments of the present invention with reference to the accompanying drawings.

[0025] Figure 1 This is a schematic diagram of the first configuration (complete release) of the peripheral vein protection stent of the patent of the present invention.

[0026] Figure 2 This is a schematic diagram of the second configuration (only the sheath funnel is released) of the peripheral venous protection stent of the patent of the present invention.

[0027] Figure 3This is a schematic diagram of the third configuration (cooperation between the cannula funnel and the rotary cutting element funnel section) of the patented peripheral venous protection stent of the present invention.

[0028] Figure 4 This is a schematic diagram of the fourth configuration (completely compressed within the outer sheath) of the patented peripheral venous protection stent of the present invention.

[0029] Figure 5 This is a schematic diagram of the internal reinforcement ribs of the sleeve funnel in the peripheral venous protection stent of the patent of this invention.

[0030] Figure 6 This is a schematic diagram of the sleeve funnel mesh structure in the peripheral venous protection stent of the patent of this invention.

[0031] Figure 7 This is a front view of the rotary cutting element part (including the barb) of the peripheral vein protection stent of the patent of this invention.

[0032] Figure 8 This is a side view of the rotary cutting element part (including the barb) of the peripheral vein protection stent of the patent of this invention.

[0033] Figure 9 This is an oblique two-dimensional view of the rotary cutting element part (including the barb) of the peripheral vein protection stent of the patent of this invention.

[0034] Figure 10 This is a schematic diagram of the third configuration (the rotary cutting element contains barbs) of the patented peripheral venous protection stent of the present invention.

[0035] Figure 11 This is a schematic diagram of the peripheral vein protection stent of the present invention cooperating with the PICC catheter in the second configuration state.

[0036] Figure 12 This is a schematic diagram of the working state of the peripheral vein protection stent of the patent of this invention. DETAILED DESCRIPTION

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the accompanying drawings. When describing the embodiments of the present invention in detail, for the sake of convenience, the schematic diagrams are not partially enlarged according to the general scale and should not be used as a limitation of the present invention.

[0038] The "proximal end" involved in the patent of this invention refers to the end closer to the operator of the peripheral venous protection stent, and the "distal end" refers to the end farther from the operator of the peripheral venous protection stent.

[0039] like Figure 1As shown, the device consists of a rotary cutting element 1, an ejector tube 2, an inner tube 3, a cannula funnel 4, an outer sheath, and a proximal handle. During use, the stent is compressed and passed through a loading sheath into the outer sheath. When compressed in the loading sheath or outer sheath, the stent assumes a fourth configuration, in which the rotary cutting element includes a straight section 5, a funnel section 6, and a rotational atherectomy section 7.

[0040] After the stent is pushed to the first predetermined position through the outer sheath, the cannula funnel is pushed out of the sheath to release it. Figure 2 As shown (hereinafter, the first predetermined position takes the right atrium or the upper edge of the right atrium as an example, and the target blood vessel takes the brachiocephalic vein and the subclavian vein as an example, that is, the description is based on central venous catheterization).

[0041] like Figure 4 As shown, the cannula funnel is at the distal end and the rotary cutting element is at the proximal end 8, and both components are compressed. Figure 5 As shown, after release, the stent is located on the proximal side of the matching device (central venous catheter), and the cannula funnel is expanded into a funnel shape under the support of the internal predetermined support ribs, and the edge naturally rolls outward to form a smooth curling edge 10, which is tightly attached to the blood vessel wall.

[0042] like Figure 7 、 8 As shown in Figures 9 and 9, when the stent is withdrawn, the cannula funnel can be fixed in position by the integrally formed barb; at this time, the central venous catheter has been inserted into the inner cavity of the inner tube through the second configuration, so after the first configuration (releasing the rotary cutting element), the cannula funnel is withdrawn through the cutting ring into the interior of the rotary cutting element to form the third configuration, as shown in Figures 9 and 9. Figure 3 or Figure 10 As shown, the catheter is then pushed forward along the central venous catheter. During the pushing process, the handle controls the ejection tube to drive the rotary cutting element to rotate, thereby cutting off the thrombus and placing it into the funnel. The cannula funnel has a fine mesh that allows blood to pass through while blocking the thrombus. Figure 6 After the target vessel is reached and the device confirms there is no thrombus blockage, the central venous catheter can be removed. After the central venous catheter is removed, the stent can be removed only after an imaging device has verified that the stent is clear.

[0043] like Figure 11 As shown, slowly push the released cannula funnel forward to scoop up the distal end of the device and insert it into the inner lumen of the inner tube. During insertion, the handle can be used to adjust the control wire to control the degree of funnel expansion to accommodate the central venous catheter. After insertion, ultrasound or other equipment is used to confirm the presence of thrombus. If the amount is small, the cannula funnel is used alone to push forward along the central venous catheter to capture the thrombus. During this process, the central venous catheter can optionally be slowly withdrawn simultaneously. After the device confirms that there is no drifting thrombus, the protective stent is pulled back into the outer sheath and removed from the body.

[0044] like Figure 12As shown, if the device confirms that the thrombus is large, adheres to the outer wall of the catheter and blocks the blood vessel, the third configuration can be used for treatment; at the same time, when withdrawing, the stent is pulled back to the outer sheath, and the compressed state after pulling back is as shown in Figure 4 As shown, the stent is in its fourth configuration (also the state before release). During retraction, the stent mesh contracts, forcefully squeezing the thrombus, reducing it to harmless fragments less than 0.3 mm in diameter. The stent then carries some of the thrombus into the catheter, achieving complete thrombus removal. If necessary, the physician can select a larger-caliber sheath to perform aspiration during stent withdrawal to assist in thrombus removal.

[0045] The peripheral vein protection stent of the present invention, when appropriately sized, can also be used for other treatments requiring thrombus removal prevention. Those skilled in the art will appreciate that the above description is merely illustrative. That is, any equivalent variations and modifications made within the scope of the present invention are intended to fall within the technical scope of the present invention.

Claims

1. A peripheral vein protection stent, comprising a rotary cutting element (1), an ejection tube (2), an inner tube (3), a cannula funnel (4), a loading sheath, and an outer sheath, characterized in that: The rotary cutting element comprises a straight section (5), a funnel section (6) and a grinding section (7); the proximal end (8) of the rotary cutting element is closed on the ejection tube, the rotary cutting element is a closed mesh cage structure, and the distal end of the rotary cutting element is closed on the cutting ring (9) nested on the inner tube to form a closed design; the outer edge of the sleeve funnel has a curling edge (10) to form a smooth curved surface; the sleeve funnel (4) can be retracted into the funnel section (6) formed by the support ribs, and the connection between the straight section and the funnel section of the rotary cutting element is tangent to the curling edge (10) of the retracted sleeve funnel.

2. The peripheral vein protection stent according to claim 1, characterized in that The rotary cutting element is a cage-shaped bracket, the middle part is a straight section (5) with several layers of mesh, the distal end is a rotary grinding section (7) with several arc-shaped rotary grinding ribs, and the proximal end is a funnel section (6) with several straight supporting ribs.

3. The peripheral vein protection stent according to claim 1 or 2, characterized in that The burr ribs of the rotary cutting element are gathered at a distal cutting ring, and the cutting ring is nested in the outer surface of the inner tube.

4. The peripheral vein protection stent according to claim 1, characterized in that The connection between the straight section and the funnel section of the rotary cutting element can be a smooth transition surface or a barb (11) integrally formed with the rotary cutting element.

5. The peripheral vein protection stent according to claim 1, characterized in that The curling edge (10) of the sleeve funnel is composed of a polytetrafluoroethylene layer containing reinforcing ribs; the reinforcing ribs are one of metal and polymer wires, rods, and sheets with shape memory function.

6. The peripheral vein protection stent according to claim 1, characterized in that The sleeve funnel is made of polytetrafluoroethylene containing a control wire, and the control wire extends from the distal end of the sleeve funnel through the inner tube to the proximal end of the stent.

7. The peripheral vein protection stent according to claim 1, characterized in that The ejector tube is one of a steel tube with threaded slits, a polymer single-layer tube, a braided tube, and a coil tube.

8. The peripheral vein protection stent according to claim 1, characterized in that The outer sheath tube has a hollow inner cavity, the ejection tube is located in the inner cavity of the outer sheath tube and extends therein, and the inner tube is located in the inner cavity of the ejection tube and extends therein.

9. The peripheral vein protection stent according to claim 1, characterized in that The rotary cutting element is a method of weaving a mesh, cutting a hollow mesh, or welding metal rods into a mesh.

10. The peripheral vein protection stent according to claim 1, characterized in that The material of the rotary cutting element is one of wire, rod and tube with shape memory function.

11. The peripheral vein protection stent according to claim 1, characterized in that The proximal end of the rotary cutting element and the ejector tube are fixed in a manner selected from the group consisting of welding, riveting, gluing, and mortise and tenon joints.

12. The peripheral vein protection stent according to claim 1, characterized in that The inner tube is made by weaving polytetrafluoroethylene wire or stretching polytetrafluoroethylene tube.

13. The peripheral vein protection stent according to claim 1, characterized in that When the inner tube is woven from polytetrafluoroethylene wire, the sleeve funnel and the inner tube are a dense mesh structure woven in one piece.

14. The peripheral vein protection stent according to claim 1, characterized in that When the inner tube is formed by stretching a polytetrafluoroethylene tube, the sleeve funnel and the inner tube are integrally expanded outwards, and the sleeve funnel has a mesh structure.

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