CN117959034A - Embolic protector delivery catheter with enhanced folding resistance and preparation method thereof - Google Patents

Abstract

The present invention provides an embolic protector delivery catheter with enhanced anti-bending properties and a preparation method thereof, which relates to the technical field of surgical instruments, wherein the delivery catheter comprises a delivery end and a recovery end, wherein 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 guidewire port; the delivery end comprises a nested inner layer and an outer layer, wherein the inner layer is made of PTFE material, and the distal hardness of the outer layer is lower than the proximal hardness, so that the distal end of the delivery end has a lower hardness, which improves its passability, while the proximal end has a higher hardness and better support, so that it is not easy to bend; a metal wire interlayer is also provided between the inner layer and the outer layer, which further improves the support of the delivery end. The delivery catheter provided by the present invention can solve the problem that the existing delivery catheters are difficult to fully meet the surgical needs when using relatively hard or relatively soft materials.

Description

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

Technical Field

The invention belongs to the technical field of surgical instruments, and in particular relates to an embolic protector delivery catheter capable of enhancing folding resistance and a preparation method thereof.

Background technique

During vascular (such as peripheral vascular, coronary artery) interventional surgery, embolic protectors are used to provide patients with tail embolism protection. Before stent implantation, the protector is placed at least 5 cm distal to the lesion to prevent thrombus escape during the surgery. After the stent is implanted, the protector is retrieved through the catheter and the captured thrombus is taken out.

The embolic protector is mainly composed 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 mounted 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 to the position through the main guidewire and then exchanged for the capture guidewire. The retrieval end has a capture guidewire port. During delivery, the delivery end of the catheter pushes the embolic protector carried by the main guidewire into place, and after placement, it adheres to the vascular 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).

However, the existing delivery catheters have the following disadvantages:

1) The delivery end of the catheter is pushed upward along the capture guidewire. Since the delivery catheter is relatively hard, it is difficult to make a bend when passing through a tortuous blood vessel. The catheter cannot reach the predetermined position and there is a risk of severing the blood vessel, which may prolong the operation time or cause the operation to fail.

2) In order to solve the problem of bending, some manufacturers use softer materials to make delivery catheters, which will cause another problem: the delivery catheter is prone to folding when passing through tortuous blood vessels, which will cause 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 able to be pushed out, resulting in prolonged operation time or failure of the operation.

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

Summary of the invention

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 the existing delivery catheters using relatively hard or relatively soft materials are difficult to fully meet surgical needs.

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

An embolic protector delivery catheter with enhanced anti-bending properties comprises a delivery end and a recovery end, wherein:

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, 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.

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

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

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.

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.

Preferably, 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.

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.

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 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.

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.

The present invention also provides a method for preparing any of the above-mentioned embolic protector delivery catheters capable of enhancing folding resistance, the method comprising the following steps:

S1. Put the PTFE etching 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 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.

Preferably, in step S3, during the heat shrinking treatment, heat shrinking is performed from the far end to the near end of the outer layer.

Beneficial effects:

(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 selects 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, while the hardness of the proximal end of the delivery end gradually increases, thereby improving its anti-bending property;

(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 that the distal end has sufficient flexibility, the proximal end can maintain sufficient support to avoid the occurrence of stress concentration.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary 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. Among them:

FIG. 1 is a schematic diagram of an embolic protector delivered via a catheter.

FIG. 2 is a front view of a delivery catheter provided in an embodiment of the present invention.

FIG. 3 is a front view of the delivery end of the delivery catheter.

FIG. 4 is an enlarged view of point A in FIG. 3 .

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

FIG. 6 is a schematic diagram of a metal wire interlayer using a gradual winding pitch.

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 section; 402. second pipe section; 403. third pipe section; 404. fourth pipe section; 405. fifth pipe section; 406. sixth pipe section; 407. seventh pipe section.

Detailed ways

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 belong to the scope of protection of the present invention.

In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and 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, and therefore should not be understood as a limitation on the present invention.

In the description of the present invention, the "proximal end" refers to an end close to an operator of the embolic protector, and the "distal end" refers to an end far from the operator of the embolic protector.

In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more features.

In the description of the present invention, it should be noted that, unless otherwise clearly stipulated 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 connection between two elements, indirect connection, or an interactive relationship between two elements.

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

In view of the problems that the hardness of the current embolic protector is difficult to choose and the bending ability and folding resistance cannot be taken into account, the present invention provides an embolic protector delivery catheter with enhanced folding resistance, which is used to deliver a filter 1, a guide wire 2 and a distal development spring 3 to the desired position. As shown in FIGS. 2 and 3 , the delivery catheter includes a delivery end 4, a recovery end 5 and a catheter body 6, wherein:

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

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

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, and the passability is good, and it 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.

As shown in FIGS. 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.

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 that the cornering resistance is small and has good passability, and can avoid bending and have sufficient support, so that the delivery catheter can reach the target position more easily, and then the embolic protector can be delivered to the right place, thereby improving the success rate and safety of the interventional surgery.

In a preferred embodiment of the present invention, the outer layer of the conveying end 4 includes a plurality of 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 hardnesses 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 increase, so that the hardness of the outer layer of the conveying end 4 gradually increases from the distal end to the proximal end, so that the conveying end 4 presents the characteristics of being soft at the distal end and hard at the proximal end.

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, so that the distal end of the conveying end 4 has better flexibility and is convenient for turning in tortuous blood vessels.

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 that the distal end of the conveying end 4 has sufficient flexibility, thereby avoiding the occurrence of stress concentration.

The metal wire interlayer 7 is obtained by winding or weaving metal wires. 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 may also be used, or metal wires of other materials may be used, such as nickel-titanium wire.

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

More preferably, as shown in FIG6 , 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 turn. Specifically, for example, when adopting the wire 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).

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 supporting catheter will be coaxially sleeved on the outside of the embolic protector delivery catheter as a proximal support. The supporting 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 portion of the wire interlayer 7 can still be located in the supporting catheter to avoid stress concentration.

The present invention also provides a method for preparing the above-mentioned embolic protector delivery catheter with enhanced anti-bending properties, the method comprising the following steps:

S1. Put the PTFE etching tube on the metal mandrel, and then 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, fix the starting end of the stainless steel round wire with a diameter of 0.025mm on the mandrel with tape, click the "Start" button to start winding. During the winding process, you need to pay attention to the real-time state of the winding to avoid overlapping wires;

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 avoid loose wires. Then, the two ends of the stainless steel round wire are welded with 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 a PTFE etched tube after the wire winding.

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 turn, and make sure that the metal wire interlayer 7 is completely covered, then closely connect the sections of the outer layer materials in turn, put a heat shrink tube on the outermost side, use a hot air gun (adjusted to 250°C) to pre-shrink from the first tube section 401 until the pre-shrinkage of the connection between the sixth tube section 406 and the seventh tube section 407 is completed, make 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 20-60min (for example, 25min, 30min, 35min, 40min, 45min, 50min, 55min). After the heat shrinkage is completed, the outer heat shrink tube is removed, and the core shaft is stretched to take out the catheter, so as to obtain the embolic protector delivery catheter with enhanced folding resistance.

In summary:

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 a layer of metal wire interlayer 7 is added 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 difficult selection of hardness and inability to balance bending ability and bending resistance in current embolic protectors.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (11)

1. An embolic protector delivery catheter with enhanced resistance to kinking, comprising a delivery end and a retrieval end, wherein:

the conveying end is positioned at the far end of the conveying catheter and is provided with a main guide wire exchange port and a first capturing guide wire port;

the recovery end is positioned at the proximal end of the conveying catheter and is provided with a second capturing guide wire port;

The delivery end comprises an inner layer and an outer layer, wherein the inner layer is made of PTFE, and the hardness of the distal end of the outer layer is lower than that of the proximal end of the outer layer.

2. An embolic protector delivery catheter with enhanced resistance to bending as in claim 1, wherein a wire interlayer is provided between the inner and outer layers.

3. An embolic protector delivery catheter that enhances resistance to bending as in claim 1, wherein the outer layer comprises a plurality of consecutive, differing durometer tube segments.

4. An embolic protector delivery catheter with enhanced resistance to kinking as in claim 2, wherein the wire sandwich is formed from wire windings, the wire winding process of the wire sandwich is selected from any one of single strand windings and double strand windings, and the wire winding pitch of the wire sandwich decreases gradually from distal end to proximal end.

5. An embolic protector delivery catheter with enhanced resistance to kinking as in claim 2, wherein the wire interlayer is braided from wires, the braiding process of the wire interlayer is selected from any one of braiding, hybrid braiding and wire-wrap braiding, and the braiding density of the wire interlayer decreases gradually from distal end to proximal end.

6. An embolic protector delivery catheter that enhances resistance to bending as in claim 3, wherein the outer layer comprises a first tube segment, a second tube segment, a third tube segment, a fourth tube segment, a fifth tube segment, a sixth tube segment, a seventh tube segment, which are sequentially consecutive.

7. An embolic protector delivery catheter with enhanced resistance to kinking as in claim 4, wherein the wire interlayer has a wire wrap pitch that varies gradually between 0.03mm and 0.1mm, the total length of the wire interlayer being between 5cm and 20cm.

8. The embolic protector delivery catheter of claim 6, wherein the first, second, third, fourth, fifth, sixth, seventh segments have progressively increasing stiffness and the first, second, third, fourth, fifth, sixth segments have progressively increasing lengths.

9. The embolic protector delivery catheter of claim 8, wherein the first, second, third, fourth, fifth, and sixth tube sections are each independently selected from pebax, TPU, or POE materials, and the seventh tube section is nylon.

10. A method of making an embolic protector delivery catheter with enhanced resistance to kinking according to any of claims 1-9, comprising the steps of:

s1, sleeving a PTFE etched tube on a metal mandrel, stretching uniformly to ensure that no folds are formed on the surface of the PTFE etched tube, and forming a metal wire interlayer on the surface of the PTFE etched tube by wire winding or braiding;

S2, after the wire winding or braiding is finished, fixing the end parts of the metal wires, and then welding the two ends of the metal wires;

S3, cutting the outer layer raw materials with different hardness according to the designed size, sequentially sleeving the outer layer raw materials on a wound PTFE etched tube, ensuring that the metal wire interlayer is completely covered, and performing heat shrinkage treatment to obtain the embolic protector conveying catheter capable of enhancing the fracture resistance.

11. The method of claim 10, wherein in step S3, the heat shrinkage is performed from the distal end to the proximal end of the outer layer during the heat shrinkage treatment.