Delivery catheter of embolic protector that is capable of enhancing bending resistance, and preparation method therefor

Abstract

A delivery catheter of an embolic protector that is capable of enhancing the bending resistance, and a preparation method therefor. The delivery catheter of an embolic protector comprises a delivery end (4) and a retrieval end (5), wherein the delivery end (4) is located at a distal end of the delivery catheter and is provided with a main guidewire exchange port and a first capture guidewire port; the retrieval end (5) is located at a proximal end of the delivery catheter and is provided with a second capture guidewire port; and the delivery end comprises an inner layer and an outer layer which are nested, the inner layer being made of a PTFE material. The hardness of a distal end of the outer layer is lower than that of a proximal end of the outer layer, such that a distal end of the delivery end has lower hardness, thus improving the passage performance of the delivery end, while a proximal end of the delivery end has higher hardness and a better supporting performance; thus, the delivery catheter does not easily bend. A metal wire interlayer (7) is further provided between the inner layer and the outer layer, thus further improving the supporting performance of the delivery end, and solving the problem that the delivery catheter has difficulty completely meeting operation requirements when the delivery catheter is made of a relatively hard or soft material.

Description

Embolic protector delivery catheter with enhanced folding resistance and preparation method thereof Technical Field

[0001] The present invention belongs to the technical field of surgical instruments, and in particular relates to an embolic protector delivery catheter with enhanced folding resistance and a preparation method thereof. Background Art

[0002] During vascular interventions (e.g., peripheral vascular and coronary artery) procedures, embolic protectors are used to protect patients from caudal embolism. Prior to stent implantation, they are placed at least 5 cm distal to the lesion to prevent thrombus escape during the procedure. After stent implantation, the protector is retrieved via a catheter, along with the captured thrombus.

[0003] The embolic protector mainly consists of a capture guidewire and a delivery catheter. The capture guidewire includes a nickel-titanium filter, a stainless steel guidewire with a polytetrafluoroethylene coating, and a distal development spring. The nickel-titanium filter is assembled on the guidewire and can rotate freely on the guidewire and can move longitudinally along the capture guidewire within a certain range. The delivery catheter is a double-headed design with a delivery end and a retrieval end at each end. The delivery end has a main guidewire exchange port and a capture guidewire port. The embolic protector can be delivered into place through the main guidewire and then exchanged for a capture guidewire. The retrieval end has a capture guidewire port. During delivery, the embolic protector carried by the catheter is pushed into place along the main guidewire. After placement, it adheres to the blood vessel wall and the delivery catheter is withdrawn. After the stent is implanted, the retrieval end of the catheter is pushed along the capture guidewire and the protector is retrieved (as shown in Figure 1).

[0004] However, existing delivery catheters have the following disadvantages:

[0005] 1) The delivery end of the catheter is advanced upward along the capture guidewire. Because the delivery catheter is relatively rigid, it is difficult to bend when passing through tortuous blood vessels. The catheter cannot reach the intended location and there is a risk of rupturing the blood vessels, which can prolong the operation or even lead to surgical failure.

[0006] 2) To solve the bending problem, some manufacturers use softer materials to make delivery catheters. This will cause another problem: the delivery catheter is prone to folding when passing through tortuous blood vessels, which will lead to stress concentration and the catheter cannot reach the predetermined position. In addition, due to the loss of the lumen, the capture guidewire may not be pushed out, resulting in prolonged operation time or even failure of the operation.

[0007] Therefore, it is necessary to provide an improved technical solution to the above-mentioned deficiencies in the prior art.

[0008] Summary of the Invention

[0009] The purpose of the present invention is to provide an embolic protector delivery catheter with enhanced folding resistance and a preparation method thereof, which has the advantages of strong bending ability, not easy to fold, and high safety, so as to solve the problem that existing delivery catheters made of relatively hard or relatively soft materials are difficult to fully meet surgical needs.

[0010] In order to achieve the above object, the present invention provides the following technical solutions:

[0011] An embolic protector delivery catheter with enhanced flexural resistance comprises a delivery end and a retrieval end, wherein:

[0012] The delivery end is located at the distal end of the delivery catheter and is provided with a main guidewire exchange port and a first capture guidewire port;

[0013] The recovery end is located at the proximal end of the delivery catheter and is provided with a second capture guide wire port;

[0014] The delivery end comprises an inner layer and an outer layer, the inner layer is made of PTFE, and the hardness of the distal end of the outer layer is lower than the hardness of the proximal end thereof.

[0015] Preferably, a metal wire interlayer is provided between the inner layer and the outer layer.

[0016] Preferably, the outer layer comprises a plurality of continuous tube sections with different hardnesses.

[0017] Preferably, the metal wire interlayer is obtained by winding metal wires, the winding process of the metal wire interlayer is selected from any one of single-strand winding and double-strand winding, and the winding pitch of the metal wire interlayer gradually decreases from the distal end to the proximal end.

[0018] Preferably, the metal wire interlayer is obtained by weaving metal wires, the weaving process of the metal wire interlayer is selected from any one of weaving, mixed weaving and wire winding weaving, and the weaving density of the metal wire interlayer gradually decreases from the distal end to the proximal end.

[0019] Preferably, the outer layer includes a first pipe segment, a second pipe segment, a third pipe segment, a fourth pipe segment, a fifth pipe segment, a sixth pipe segment, and a seventh pipe segment in sequence from the distal end to the proximal end.

[0020] Preferably, the wire winding pitch of the metal wire interlayer gradually changes between 0.03 mm and 0.1 mm, and the total length of the metal wire interlayer is 5 cm to 20 cm.

[0021] Preferably, the hardness of the first pipe segment, the second pipe segment, the third pipe segment, the fourth pipe segment, the fifth pipe segment, the sixth pipe segment and the seventh pipe segment gradually increases, and the lengths of the first pipe segment, the second pipe segment, the third pipe segment, the fourth pipe segment, the fifth pipe segment and the sixth pipe segment gradually increase.

[0022] Preferably, the first pipe segment, the second pipe segment, the third pipe segment, the fourth pipe segment, the fifth pipe segment and the sixth pipe segment are each independently selected from pebax, TPU or POE materials, and the seventh pipe segment is made of nylon.

[0023] The present invention also provides a method for preparing any of the above-mentioned embolic protector delivery catheters with enhanced folding resistance, the method comprising the following steps:

[0024] S1. Put the PTFE etched tube on the metal core shaft, then stretch it evenly to ensure that there are no wrinkles on the surface, and then form a metal wire interlayer on the surface of the PTFE etched tube by winding or weaving;

[0025] S2. After the wire winding or braiding is completed, the ends of the metal wire are fixed, and then the two ends of the metal wire are welded;

[0026] S3. Cut the outer layer materials of different hardness according to the designed size, and then put them on the PTFE etched tube that has been wrapped with wire in sequence, and ensure that the metal wire interlayer is completely covered, and then perform heat shrinkage treatment to obtain the embolic protector delivery catheter with enhanced flexural resistance.

[0027] Preferably, in step S3, during the heat shrinking treatment, heat shrinking is performed from the distal end to the proximal end of the outer layer. Beneficial effects:

[0028] (1) The present invention adds a layer of metal wire interlayer between the inner and outer layers of the delivery catheter to enhance the strength of the delivery catheter, and adopts a structure with gradually varying hardness in the outer layer, so that the hardness of the delivery end of the delivery catheter gradually increases toward the recovery end, thereby having a softer delivery end, which is easy to pass through tortuous blood vessels and is not easy to scratch the blood vessels. The hardness of the proximal end of the delivery end gradually increases, thereby improving its anti-bending property;

[0029] (2) The hardness and length of the first pipe segment, the second pipe segment, the third pipe segment, the fourth pipe segment, the fifth pipe segment, and the sixth pipe segment gradually increase. On the premise of ensuring sufficient flexibility at the distal end, the proximal end can maintain sufficient support to avoid the occurrence of stress concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings and the accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. Among them:

[0031] FIG1 is a schematic diagram of an embolic protector delivered via a catheter.

[0032] FIG2 is a front view of the delivery catheter provided by an embodiment of the present invention.

[0033] FIG3 is a front view of the delivery end of the delivery catheter.

[0034] FIG4 is an enlarged view of point A in FIG3 .

[0035] FIG5 is a cross-sectional view of the delivery end of the catheter along the axial direction.

[0036] FIG6 is a schematic diagram of a metal wire interlayer with a gradual winding pitch.

[0037] In the figure: 1. filter screen; 2. guide wire; 3. distal development spring; 4. delivery end; 5. recovery end; 6. catheter body; 7. wire interlayer; 401. first pipe segment; 402. second pipe segment; 403. third pipe segment; 404. fourth pipe segment; 405. fifth pipe segment; 406. sixth pipe segment; 407. seventh pipe segment. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention are within the scope of protection of the present invention.

[0039] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0040] In the description of the present invention, “proximal end” refers to an end close to an operator of the embolic protector, and “distal end” refers to an end away from an operator of the embolic protector.

[0041] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0042] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or to implicitly indicate the quantity of the technical features indicated. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more features.

[0043] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, it can be a fixed connection or a movable connection, a detachable connection or a non-detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be internal communication between two elements, indirect communication, or an interactive relationship between two elements.

[0044] The present invention will be described in detail below with reference to the embodiments. It should be noted that the embodiments and features of the embodiments of the present invention can be combined with each other without conflict.

[0045] The present invention addresses the problems of current embolic protectors, such as difficulty in selecting a good hardness and difficulty in balancing bending resistance and bending ability, by providing an embolic protector delivery catheter with enhanced bending resistance, which is used to deliver a filter 1, a guide wire 2, and a distal development spring 3 to a desired position. As shown in Figures 2 and 3, the delivery catheter includes a delivery end 4, a recovery end 5, and a catheter body 6, wherein:

[0046] The delivery end 4 is located at the distal end of the delivery catheter and is provided with a main guidewire exchange port and a first capture guidewire port, wherein the main guidewire exchange port is used to allow the main guidewire to enter the delivery catheter, and the first capture guidewire port is used to allow the capture guidewire to enter the delivery catheter and reach the lesion site;

[0047] The retrieval end 5 is located at the proximal end of the delivery catheter and is provided with a second capture guidewire port, so that the retrieval end 5 can reach the lesion site through the second capture guidewire port and retrieve the embolic protector;

[0048] As shown in Figure 5, the delivery end 4 includes an inner layer and an outer layer. The inner layer is made of PTFE material and has relatively good lubrication ability, which can reduce the friction between the guide wire and the embolic protector. The hardness of the distal end of the outer layer is lower than its proximal hardness. The softer distal end is used to enhance the cornering ability, has good passability, and is easy to reach the predetermined position. When the distal end contacts the blood vessel, it is not easy to scratch the blood vessel due to the soft material of the distal end, and the safety is relatively high.

[0049] As shown in Figures 3 to 5, a metal wire interlayer 7 is provided between the inner layer and the outer layer, which can improve the strength of the conveying end 4 and avoid the buckling phenomenon caused by the conveying end 4 being too soft.

[0050] The present invention obtains a delivery end 4 that is softer at the distal end and harder at the proximal end by adopting an outer layer of the delivery end 4 whose hardness gradually increases from the distal end, and improves the proximal strength of the delivery end 4 by providing a metal wire interlayer 7, so that the distal end of the delivery end 4 is more flexible and the proximal end has better support, which can ensure low cornering resistance and good passability, avoid buckling, and have sufficient support, so that the delivery catheter can reach the target position more easily, and then deliver the embolic protector to its place, thereby improving the success rate and safety of interventional surgery.

[0051] In a preferred embodiment of the present invention, the outer layer of the delivery end 4 includes several continuous pipe segments with different hardnesses. More specifically, the outer layer includes, from the distal end to the proximal end, a first pipe segment 401, a second pipe segment 402, a third pipe segment 403, a fourth pipe segment 404, a fifth pipe segment 405, a sixth pipe segment 406, and a seventh pipe segment 407 in sequence, and the hardness of the first pipe segment 401, the second pipe segment 402, the third pipe segment 403, the fourth pipe segment 404, the fifth pipe segment 405, the sixth pipe segment 406, and the seventh pipe segment 407 gradually increases, so that the hardness of the outer layer of the delivery end 4 gradually increases from the distal end to the proximal end, so that the delivery end 4 presents the characteristics of being soft at the distal end and hard at the proximal end.

[0052] Furthermore, the lengths of the first tube segment 401, the second tube segment 402, the third tube segment 403, the fourth tube segment 404, the fifth tube segment 405, and the sixth tube segment 406 gradually increase, so that the first tube segment 401, the second tube segment 402, the third tube segment 403, the fourth tube segment 404, and the fifth tube segment 405 with smaller hardness have shorter lengths, thereby making the distal end of the delivery end 4 more flexible and facilitating turning in tortuous blood vessels.

[0053] In a preferred embodiment of the present invention, the first pipe segment 401, the second pipe segment 402, the third pipe segment 403, the fourth pipe segment 404, the fifth pipe segment 405, and the sixth pipe segment 406 are made of pebax material, and the seventh pipe segment 407 is made of nylon material, and the hardness of the first pipe segment 401, the second pipe segment 402, the third pipe segment 403, the fourth pipe segment 404, the fifth pipe segment 405, and the sixth pipe segment 406 gradually increases; through the above-mentioned arrangement, the proximal end of the conveying end 4 can maintain sufficient support while ensuring sufficient flexibility at the distal end of the conveying end 4, thereby avoiding the occurrence of stress concentration.

[0054] The metal wire interlayer 7 is obtained by winding or weaving metal wire. The winding process of the metal wire interlayer 7 is selected from any one of single-strand winding and double-strand winding, and the weaving process is selected from any one of weaving, mixed weaving and wire weaving. The metal wire used is preferably a stainless steel round wire with a diameter of 0.025 mm. In other embodiments, stainless steel wires of other diameters can also be used, or metal wires of other materials can be used, such as nickel-titanium wire.

[0055] The wire interlayer 7 can be prepared with an equidistant wire winding pitch. The support force provided by such a wire interlayer 7 at the far end and the proximal end of the conveying end 4 is the same, and the hardness difference between the far end and the proximal end of the conveying end 4 is small. At this time, the wire winding pitch of the wire interlayer 7 can be fixed at 0.06 mm, taking into account both bending resistance and flexibility.

[0056] More preferably, as shown in Figure 6, the winding pitch or weaving density of the metal wire interlayer 7 can be set to a structure that gradually decreases from the distal end to the proximal end, that is: the closer to the distal end, the greater the winding pitch or weaving density of the metal wire, the smaller the supporting force provided, the better the softness of the corresponding position at the distal end of the conveying end 4, and the easier it is to bend. Specifically, for example, when adopting the winding process, the winding pitch of the metal wire interlayer 7 gradually changes between 0.03mm and 0.1mm (for example, 0.04mm, 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm).

[0057] The total length of the wire interlayer 7 is 5cm to 20cm (for example, 6cm, 7cm, 8cm, 9cm, 10cm, 11cm, 12cm, 13cm, 14cm, 15cm, 16cm, 17cm, 18cm, 19cm), preferably 18cm. Taking carotid artery intervention surgery as an example, the average length from the aorta to the C4 segment (also known as the cavernous sinus segment) is 15cm. During normal surgical operations, a support catheter will be coaxially sleeved on the outside of the embolic protector delivery catheter as a proximal support. The support catheter is generally placed in the C1 segment (also known as the extracranial segment). The 18cm length of the wire interlayer 7 can ensure that after the delivery catheter is in place, a part of the wire interlayer 7 can still be located in the support catheter to avoid stress concentration.

[0058] The present invention also provides a method for preparing the above-mentioned embolic protector delivery catheter with enhanced folding resistance, the method comprising the following steps:

[0059] S1. Sleeve the PTFE etched tube onto the metal mandrel and stretch it evenly to ensure that there are no wrinkles on the surface. Then fix the assembled metal mandrel on the chucks on both sides of the wire winding machine. Select the corresponding parameter program and fix the starting end of the 0.025mm diameter stainless steel round wire to the mandrel with tape. Click the "Start" button to start the wire winding. During the wire winding process, you need to pay attention to the real-time status of the wire winding to avoid wire overlap.

[0060] S2. After the wire winding is completed, the end of the stainless steel round wire is fixed. The other end of the round wire can be fixed to the surface of the mandrel with tape to prevent loose wires. Then, the two ends of the stainless steel round wire are welded using a laser welding device to ensure that no loose wires will appear. A metal wire interlayer 7 is obtained. Then, the tape is torn off to obtain the PTFE etched tube after the wire winding.

[0061] S3. Cut the tubular outer layer materials of different hardness according to the designed size, and then put them on the PTFE etched tube after the wire wrapping in sequence, and make sure that the metal wire interlayer 7 is completely covered. Then, closely connect the outer layer materials of each section in sequence, put a heat shrink tube on the outermost side, and use a hot air gun (adjusted to 250℃) to pre-shrink from the first tube section 401 until the pre-shrinkage is completed at the connection between the sixth tube section 406 and the seventh tube section 407, making sure that there are no bubbles in the pre-shrinkage area, and then install the pre-shrinked delivery conduit into the film-coated heat shrink device. Prepare, start the equipment, and perform automatic heat shrinkage at 200-250°C (for example, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C) for 20-60 minutes (for example, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes). After the heat shrinkage is completed, remove the outer heat shrink tube, stretch the core shaft, and take out the catheter to obtain the embolic protector delivery catheter with enhanced flexure resistance.

[0062] In summary:

[0063] The present invention adopts a structure with gradually varying hardness in the outer layer of the delivery catheter, so that the hardness of the delivery end 4 of the delivery catheter gradually increases toward the recovery end 5, thereby having a softer delivery end 4, which is easy to pass through tortuous blood vessels and is not easy to scratch the blood vessels. The hardness of the proximal end of the delivery end 4 gradually increases, thereby improving its bending resistance, and adding a layer of metal wire interlayer 7 between the inner and outer layers to enhance the strength of the delivery catheter, further improving the bending resistance of the proximal end of the delivery tube, which can effectively solve the problems of the current embolic protector that it is difficult to choose the hardness and it is difficult to balance the bending ability and bending resistance.

[0064] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An embolic protector delivery catheter with enhanced folding resistance, characterized in that: It includes the delivery end and the recovery end, where: The delivery end is located at the distal end of the delivery catheter and is provided with a main guidewire exchange port and a first capture guidewire port; The recovery end is located at the proximal end of the delivery catheter and is provided with a second capture guide wire port; The delivery end comprises an inner layer and an outer layer, wherein the inner layer is made of PTFE material, and the hardness of the distal end of the outer layer is lower than the hardness of the proximal end thereof.

2. The embolic protector delivery catheter with enhanced folding resistance according to claim 1, characterized in that: A metal wire interlayer is arranged between the inner layer and the outer layer.

3. The embolic protector delivery catheter with enhanced folding resistance according to claim 1, characterized in that: The outer layer includes a plurality of continuous tube sections with different hardnesses.

4. The embolic protector delivery catheter with enhanced folding resistance according to claim 2, characterized in that: The metal wire interlayer is obtained by winding metal wires. The winding process of the metal wire interlayer is selected from any one of single-strand winding and double-strand winding. The winding pitch of the metal wire interlayer gradually decreases from the distal end to the proximal end.

5. The embolic protector delivery catheter with enhanced folding resistance according to claim 2, characterized in that: The metal wire interlayer is obtained by weaving metal wires. The weaving process of the metal wire interlayer is selected from any one of weaving, mixed weaving and wire winding weaving. The weaving density of the metal wire interlayer gradually decreases from the distal end to the proximal end.

6. The embolic protector delivery catheter with enhanced folding resistance according to claim 3, characterized in that: The outer layer includes, from the distal end to the proximal end, a first pipe segment, a second pipe segment, a third pipe segment, a fourth pipe segment, a fifth pipe segment, a sixth pipe segment, and a seventh pipe segment in sequence.

7. The embolic protector delivery catheter with enhanced folding resistance according to claim 4, characterized in that: The wire winding pitch of the metal wire interlayer gradually changes between 0.03 mm and 0.1 mm, and the total length of the metal wire interlayer is 5 cm to 20 cm.

8. The embolic protector delivery catheter with enhanced folding resistance according to claim 6, characterized in that: The hardness of the first pipe segment, the second pipe segment, the third pipe segment, the fourth pipe segment, the fifth pipe segment, the sixth pipe segment and the seventh pipe segment gradually increases, and the length of the first pipe segment, the second pipe segment, the third pipe segment, the fourth pipe segment, the fifth pipe segment and the sixth pipe segment gradually increases.

9. The embolic protector delivery catheter with enhanced folding resistance according to claim 8, characterized in that: The first pipe segment, the second pipe segment, the third pipe segment, the fourth pipe segment, the fifth pipe segment and the sixth pipe segment are each independently selected from pebax, TPU or POE materials, and the seventh pipe segment is made of nylon.

10. The method for preparing an embolic protector delivery catheter capable of enhancing folding resistance according to any one of claims 1 to 9, characterized in that: The steps include: S1. Put the PTFE etching tube on the metal core shaft, and then stretch it evenly to ensure that there are no wrinkles on the surface, and then form a metal wire sandwich on the surface of the PTFE etching tube by winding or weaving; S2. After the wire winding or braiding is completed, the ends of the metal wire are fixed, and then the two ends of the metal wire are welded; S3. Cut the outer layer materials of different hardness according to the designed size, and then put them on the PTFE etched tube after the wire wrapping in sequence, and ensure that the metal wire interlayer is completely covered, and then perform heat shrinkage treatment to obtain the embolic protector delivery catheter with enhanced anti-bending properties.

11. The method for preparing an embolic protector delivery catheter with enhanced folding resistance according to claim 10, characterized in that: In step S3, during the heat shrinking treatment, heat shrinking is performed from the far end to the near end of the outer layer.

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