Guiding extension catheter

Abstract

A novel guiding extension catheter capable of being inserted further distally into the coronary artery is provided. A guiding extension catheter 10 includes a distal rod 12 and a proximal rod 14. The main body portion 16 of the distal rod 12 is placed on a support platform 30 of a three-point bending test fixture with a distance of 15 mm between fulcrums 32. At the center between fulcrums 32, a pressure head 34, approaching the support platform 30 at a speed of 10 mm / min, presses the main body portion 16 from the side, deforming it until it twists. The maximum load acting on the main body portion 16 is 0.1 N or more and 0.6 N or less. Furthermore, the distal rod 12 is provided with a front end piece 18 that is more flexible than the main body portion 16. The length of the front end piece 18 is 2.5 mm or more, and the front end piece 18 has a marking portion incorporating powder made of an X-ray impermeable material.

Description

Technical Field

[0001] The present invention relates to a guiding extension catheter, for example, used in percutaneous coronary intervention (PCI) to deliver a therapeutic catheter to a more distal lesion site. Background Technology

[0002] Previously, percutaneous coronary intervention (PCI) using a therapeutic catheter was performed as a less invasive treatment method than open-chest surgery, for conditions such as stenosis or occlusion of the coronary arteries. PCI involves guiding a therapeutic catheter to the site of the lesion or narrowing in the coronary artery using a guide catheter, and then performing treatment using the catheter delivered distal to the lesion.

[0003] Incidentally, considering the passageway through the body to the entrance of the coronary artery, the guiding catheter requires excellent pushability, thus demanding high torque transmission efficiency and torsion resistance. Therefore, it is difficult to insert the guiding catheter into thin and complexly tortuous coronary arteries. Furthermore, if a therapeutic catheter is to be inserted into the coronary artery from its distal opening, which is positioned to hang at the entrance of the coronary artery, the therapeutic catheter sometimes cannot fully follow the tortuosity of the coronary artery, preventing it from being inserted near the distal lesion site.

[0004] Therefore, to support the delivery of therapeutic catheters to more distant lesion sites, International Patent Publication No. 2018 / 030075 (Patent Document 1) discloses a guiding extension catheter inserted into the coronary artery. The guiding extension catheter is inserted through the guiding catheter and into the coronary artery from its distal end. The guiding extension catheter is inserted into the coronary artery through the lumen of the guiding catheter pre-inserted into the coronary artery, and therefore its diameter is smaller than that of the guiding catheter. The guiding extension catheter has better tracking ability for tortuous coronary arteries than the guiding catheter, enabling it to reach more distant sites of the coronary artery and deliver the therapeutic catheter to more distant lesion sites.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: International Publication No. 2018 / 030075 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] However, there are limitations to the range in which conventional guiding extension catheters can be inserted into coronary arteries, etc. In order to treat lesions in distant parts of coronary arteries, etc. using therapeutic catheters, it is sometimes necessary to insert guiding extension catheters that can reach further into coronary arteries, etc.

[0010] The problem to be solved by the present invention is to provide a novel guiding extension catheter that can be inserted further into the coronary artery or the like.

[0011] Methods for solving problems

[0012] Hereinafter, preferred embodiments for mastering the present invention will be described. However, the embodiments described below are exemplary embodiments and can be used not only in appropriate combinations with each other, but also in appropriate combinations with any of the constituent elements described in other embodiments, as can be identified and used as independently as possible. Therefore, the present invention is not limited to the embodiments described below, and various other embodiments can be implemented.

[0013] In the first embodiment, a guide extension conduit has a tubular distal rod provided at the front end of the proximal rod of the guide extension conduit. The distal rod's main body is placed on a support platform of a three-point bending test fixture with a distance of 15 mm between its fulcrums. At the center of the support platform between the fulcrums, a pressure head that moves relative to the support platform at a relative speed of 10 mm / min presses against the main body from the side, thereby deforming the main body until it twists. The maximum load acting on the main body is 0.1 N or more and 0.6 N or less. Furthermore, a front end piece, more flexible than the main body, is provided at a position on the distal rod closer to the front end of the main body. The front end piece has a length of 2.5 mm or more and includes a marking portion incorporating powder made of an X-ray impermeable material.

[0014] The guide extension catheter, structured according to this method, ensures the conformability of the main body of the distal rod to the curvature of blood vessels caused by bending deformation, and avoids a decrease in pushability and torsion resistance due to excessive flexibility. Therefore, a high degree of conformity to the shape of the coronary artery or similar artery can be achieved in the distal rod, allowing it to be inserted further distal to the coronary artery or similar artery.

[0015] Furthermore, by giving the main body of the distal rod a certain degree of rigidity and providing a front end piece that is softer than the main body, the front end piece, which easily follows the curvature of the coronary artery when passing through a sharply curved section, for example, can guide the main body. Therefore, the front end of the main body can easily be directed toward the extension direction of the coronary artery, and the front end piece can easily guide the main body toward the extension direction of the coronary artery.

[0016] In order to effectively guide the main body, the front end needs to have a length dimension that can deform into a curved shape to follow the coronary artery, etc. Therefore, by setting the length dimension of the front end to 2.5 mm or more, the passage of the distal rod relative to the coronary artery, etc., is effectively improved through the bending deformation of the flexible front end.

[0017] In conventional guiding and extending catheters, to ensure visual visibility of the tip under X-ray fluoroscopy, a ring-shaped marker is fitted to the tip. However, the soft area of ​​the tip is restricted by this rigid marker, which can negatively impact insertion patency. Therefore, in this method, the marker portion ensuring visual visibility under X-ray fluoroscopy is formed from a material incorporating powder composed of an X-ray-impermeable material, thus possessing sufficient flexibility. By incorporating this flexible marker portion into the tip piece, it is possible to ensure visual visibility of the distal rod tip under X-ray fluoroscopy while preventing the actual length of the tip piece from being shortened due to the rigid marker, thereby achieving excellent tracking of the distal rod to blood vessels, etc.

[0018] Furthermore, the length of the tip piece varies depending on factors such as the flexibility of the material used for the tip piece, and is preferably 10 mm or less. This is because if the flexible tip piece is too long, deformation can easily occur at the tip of the distal rod formed by the tip piece, potentially causing the lumen of the distal rod to be flattened and blocked, or increasing resistance when inserted into a blood vessel.

[0019] The second method, based on the guiding and extending catheter described in the first method, provides a coating formed of a hydrophilic polymer on the outer peripheral surface of the distal rod in a length region extending from the front end of the distal rod toward the base end but not reaching the base end.

[0020] According to the guiding extension catheter formed with the structure of this method, when the distal rod is inserted into the guiding catheter, coronary artery, etc., the sliding property of the outer peripheral surface of the distal rod is improved, making insertion easier. In addition, since the coating is provided in the length region that does not reach the base of the distal rod that should remain in the guiding catheter, it is possible to prevent the distal rod from becoming difficult to position relative to the guiding catheter due to the coating, such as preventing the distal rod from falling out of the guiding catheter.

[0021] The third method, based on the guiding and extending catheter described in the first or second method, provides an anti-slip part on the outer peripheral surface of the base portion of the distal rod.

[0022] By providing an anti-slip portion at the base of the distal rod that should remain inside the guiding catheter, the distal rod becomes easier to position relative to the guiding catheter, preventing adverse situations such as the distal rod being incorrectly exposed from the guiding catheter as a whole.

[0023] The fourth method, based on the guiding extension conduit described in any of the first to third methods, involves the main body portion of the distal rod being twisted by a twist test fixture having an outer diameter of 3 mm or less, which is wound around a twist test fixture having a cylindrical outer circumferential surface.

[0024] The guiding extension catheter, constructed according to this method, is less prone to twisting in its main body, thus reducing the likelihood of decreased pushability or poor insertion and patency of the therapeutic catheter caused by twisting. Furthermore, the main body of the distal rod can be bent to a smaller radius of curvature without twisting, thereby providing excellent tracking of tortuous coronary arteries.

[0025] The fifth method, based on the guiding extension conduit described in any of the first to fourth methods, has a maximum load value of 4.0N or more when the main body portion of the distal rod is further pressed into the flattening clamp by 0.5mm in the approach direction toward the support surface from a state in which it is radially clamped between the support surface and the flattening clamp and a load of 0.5N is applied.

[0026] The guide extension catheter, formed according to this method, achieves excellent flexibility in its main body portion, which is considered helpful for following coronary arteries, etc., and stably maintains its cross-sectional shape by ensuring radial flattening resistance. Therefore, for example, it can prevent the contact area with coronary arteries, etc., from increasing due to the distal rod deforming into an elliptical cross-section, and can reduce resistance during insertion.

[0027] The sixth method, based on the guiding extension catheter described in any of the first to fifth methods, involves using a retaining clamp to constrain the distal rod connected to the front end piece at a position offset from the front end by 5 mm from the front end towards the base end. The retaining clamp is moved relative to the pressing clamp at a pressing speed of 10 mm / min from a state where the front end face of the front end piece is in contact with the pressing clamp. The maximum load value when the front end piece is compressed by 1 mm along its length is 0.5 N or more and 1.5 N or less.

[0028] The guide extension catheter, which is structured in accordance with this method, has a tip piece that is sufficiently flexible while ensuring the rigidity (stiffness) required for insertion into the coronary artery or the like, thereby more effectively ensuring the guide extension catheter's homing ability towards the coronary artery or the like.

[0029] Invention Effects

[0030] According to the present invention, a guiding extension catheter can be inserted to a more distal location, such as the coronary artery. Attached Figure Description

[0031] Figure 1 This is a side view showing the guiding extension catheter as a first embodiment of the present invention.

[0032] Figure 2 It is an enlarged representation Figure 1 A cross-sectional view of the main part of the guiding extension catheter.

[0033] Figure 3 It indicates composition Figure 1 The figure shows a three-point bending test of the main body of the distal rod of the guiding extension catheter.

[0034] Figure 4 It indicates composition Figure 1 A diagram showing the flexibility test of the distal end portion of the guide extension catheter.

[0035] Figure 5 It indicates composition Figure 1 The figure shows the torsion resistance test of the distal rod of the guiding extension catheter.

[0036] Figure 6 It indicates composition Figure 1 A diagram of the flattening test of the distal rod of the guiding extension catheter.

[0037] Figure 7 It includes Figure 1 Side view of the catheter assembly of the guiding extension catheter.

[0038] Figure 8 It means Figure 7 A diagram showing the usage status of the conduit assembly.

[0039] Figure 9 This is a photograph showing the test apparatus used in the follow-up test of the guiding extension catheter.

[0040] Figure 10A This indicates that the guiding extension catheters of Examples 1 to 6 are inserted into... Figure 9 A photograph of the results of a follow-up test on the left anterior descending branch of the experimental setup shown.

[0041] Figure 10B This indicates that the guiding extension catheters of Comparative Examples 1 to 6 are inserted into... Figure 9 A photograph of the results of a follow-up test on the left anterior descending branch of the experimental setup shown.

[0042] Figure 11A This indicates that the guiding extension catheters of Examples 1 to 6 are inserted into... Figure 9 A photograph of the results of the follow-up test of the left gyro branch of the experimental setup shown.

[0043] Figure 11BThis indicates that the guiding extension catheters of Comparative Examples 1 to 6 are inserted into... Figure 9 A photograph of the results of the follow-up test of the left gyro branch of the experimental setup shown.

[0044] Figure 12A This indicates that the guiding extension catheters of Examples 1 to 6 are inserted into... Figure 9 A photograph of the results of a follow-up test of the right coronary artery R1 of the experimental setup shown.

[0045] Figure 12B This indicates that the guiding extension catheters of Comparative Examples 1 to 6 are inserted into... Figure 9 A photograph of the results of a follow-up test of the right coronary artery R1 of the experimental setup shown.

[0046] Figure 13A This indicates that the guiding extension catheters of Examples 1 to 6 are inserted into... Figure 9 A photograph of the results of a follow-up test of the right coronary artery R2 of the experimental setup shown.

[0047] Figure 13B This indicates that the guiding extension catheters of Comparative Examples 1 to 6 are inserted into... Figure 9 A photograph of the results of a follow-up test of the right coronary artery R2 of the experimental setup shown.

[0048] Figure 14 It is a graph showing the results of a three-point bending test on the main body of the distal rod.

[0049] Figure 15 It is a chart showing the measurement results of the length of the front end piece of the distal rod.

[0050] Figure 16 It is a graph showing the results of a flexibility test on the front end of the distal rod.

[0051] Figure 17 It is a graph showing the results of the torsional resistance test of the distal rod.

[0052] Figure 18 It is a graph showing the results of the flattening test on the distal rod. Detailed Implementation

[0053] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0054] exist Figure 1 In this first embodiment of the invention, a guiding extension catheter 10 for coronary artery treatment is shown. The guiding extension catheter 10 is a quick-exchange type catheter, having a distal stent 12 and a proximal stent 14.

[0055] The distal rod 12 is a generally cylindrical tube, formed, for example, from a soft synthetic resin. The distal rod 12 includes a main body portion 16 and a front end piece 18 disposed on the front end side of the main body portion 16.

[0056] The main body 16 of the distal rod 12 is a so-called braided tube, for example, as... Figure 2 As shown, the structure has a metal braided body 24 disposed between an inner layer 20 and an outer layer 22 formed of a synthetic resin or the like. Furthermore, the inner layer 20 and the outer layer 22 are fixed together, for example, by close bonding, welding, or integral molding, thereby embedding the braided body 24. In the case where the main body 16 has a three-layer structure of inner layer 20, outer layer 22, and braided body 24, the inner layer 20 and outer layer 22 can be formed of different materials or the same material. For example, the inner layer 20 and outer layer 22 are formed of synthetic resins such as fluorine-based, polyamide-based, polyester-based, or polyurethane-based resins. By forming such a three-layer structure, the main body 16 has flexibility in the bending direction and improves the efficiency of load transmission in the axial direction, achieving both flexibility in bending and pushability during insertion.

[0057] The front end piece 18, which constitutes the front end portion 26 of the distal rod 12, is more flexible than the main body portion 16 and is more easily deformed relative to load input. The front end piece 18 may be formed of a different material than the main body portion 16, or it may be formed of the same material as the inner layer 20 and outer layer 22 of the main body portion 16. For example, it may be more flexible than the main body portion 16 due to the absence of the braid 24, the different forming materials, etc.

[0058] The front end piece 18, for example, has a marking portion formed by a forming material in which powder composed of an X-ray impermeable material is mixed into a resin. In this embodiment, the entire front end piece 18 is formed by a forming material incorporating X-ray impermeable powder, and the entire front end piece 18 is formed as a marking portion. Of course, it is not necessary for the entire front end piece 18 to be a marking portion; for example, a marking portion may be provided only partially on the front end piece 18. For example, either the front end portion or the base portion of the front end piece 18 may be designated as a marking portion, or a marking portion may be provided in the middle of the front end piece 18. The X-ray impermeable powder used for the marking portion is not particularly limited as long as it is a material with low X-ray transmittance and whose adverse effects on the human body are not a problem; for example, bismuth oxide or tungsten powder, which has better visual recognition under X-ray fluoroscopy, are preferred. The marking portion is preferably softer than the main body portion 16 of the distal rod 12, but for example, if the marking portion is provided on a part of the front end piece 18, the marking portion may be harder than the main body portion 16.

[0059] The axial length of the front end piece 18 is 2.5 mm or more. Furthermore, the length of the front end piece 18 is preferably 10 mm or less. More preferably, the length of the front end piece 18 is 3 mm or more and 7 mm or less; in this embodiment, it is approximately 4 mm.

[0060] The distal rod 12 has a coating 28. The coating 28 is formed of a hydrophilic polymer, such as polyvinylpyrrolidone (PVP), methyl vinyl ether-maleic anhydride copolymer (VEMA), acrylic, or hyaluronic acid-based coating materials. The coating 28 is configured to cover the outer peripheral surfaces of the front end piece 18 and the main body portion 16 on the front end side of the connecting tube 48 (described later), and is provided on the outer peripheral surface of the distal rod 12 in a length region extending from the front end of the distal rod 12 toward the base end but not reaching the base end. Preferably, the coating 28 is provided in a length region of more than half the total length of the distal rod 12; in this embodiment, it is provided in approximately two-thirds of the length. The coating 28 may also be configured to cover approximately the entire outer peripheral surface from the front end of the front end piece 18 in the distal rod 12 to the base end of the main body portion 16. In this case, for example, at the base end of the main body portion 16, the coating 28 is covered by the connecting tube 48 (described later), thereby preventing the coating 28 from being exposed on the outer peripheral surface at the base end of the main body portion 16.

[0061] In a three-point bending test, the maximum load applied to the main body portion 16 of the distal rod 12 until it deforms and twists is less than 0.6 N. By setting the bending characteristics of the main body portion 16 as described above, the main body portion 16 allows for large lateral deflection before twisting, exhibiting excellent flexibility that produces lateral bending deformation even with relatively small load inputs.

[0062] Furthermore, in a three-point bending test, the maximum load applied to the main body portion 16 of the distal rod 12 until it deforms and twists is 0.1 N or more, preferably 0.3 N or more. This achieves a balance of flexibility and a degree of shape stability in the main body portion 16 of the distal rod 12, preventing unnecessary deformation when the guide extension conduit 10 is pressed towards the front end, thus effectively transmitting the operating force to the front end.

[0063] Furthermore, the three-point bending test can be performed as follows. For example... Figure 3 As shown, the tester first placed the main body 16 of the distal rod 12 across the distance between the fulcrums 32 on the support platform 30 of the test fixture, where the distance between the fulcrums 32 was set to 15 mm. Then, the pressure head 34, which was moving relative to the support platform 30 at a relative moving speed of 10 mm / min, was moved from the side... Figure 3The upper part of the rod is pressed against the main body 16, causing the main body 16 to deform until it twists. Then, the maximum load value acting on the main body 16 when it twists is measured. In addition, the length of the main body 16 of the distal rod 12 used in the three-point bending test is 50 mm.

[0064] Preferably, the maximum load value acting on the main body portion 16 of the distal stem 12, as determined by the aforementioned three-point bending test, is greater than the maximum load value acting on the tip piece 18, as determined by the same three-point bending test. This ensures that the bending rigidity of the main body portion 16 of the distal stem 12 is greater than that of the tip piece 18, preventing excessive deformation of the main body portion 16 from reducing the efficiency of force transmission when the operating force pressing the guiding extension catheter 10 towards the anterior side is applied. Furthermore, upon contact with the tip piece 18, the tip piece 18, being more flexible than the main body portion 16 of the distal stem 12, deforms first, thereby facilitating the extension of the tip piece 18 towards the coronary artery 66 (described later).

[0065] The maximum load value of the front end portion 26 of the distal rod 12, as determined by the flexibility test, is 0.5N or more and 1.5N or less. By setting the flexibility of the front end portion 26 as described above, the contact of the front end portion 26 with respect to the axial direction can ensure a certain degree of shape stability and allow for flexible deformation.

[0066] Furthermore, the flexibility test of the front end portion 26 can be performed as follows. For example... Figure 4 As shown, the experimenter first used the retaining clamp 36 to constrain the portion of the distal rod 12, which is 5 mm from the front end and close to the base end, so that the front end face of the distal rod 12, i.e., the front end face of the front end piece 18, overlaps with the pressing clamp 38 in an abutting state. The retaining clamp 36 is constructed, for example, by combining a cylindrical outer cylinder portion that constrains the outer circumferential surface of the distal rod 12 and a columnar inner shaft portion that constrains the inner circumferential surface of the distal rod 12. Next, the retaining clamp 36 is moved close to the pressing clamp 38 at a speed of 10 mm / min, compressing the front end portion (front end piece 18) of the distal rod 12 exposed from the retaining clamp 36 by 1 mm along the length direction, and the maximum load value at this time is measured.

[0067] The main body 16 of the distal rod 12 is directed towards having Figure 5In the torsion resistance test conducted by winding the cylindrical outer peripheral surface of the shown test fixture 40, torsion may occur when it is bent with a small radius of curvature of 3 mm or less. In other words, the main body 16 has excellent torsion resistance, making it less prone to torsion due to bending deformation with a radius of curvature greater than 3 mm. By setting the torsion resistance of the main body 16 as described above, the main body 16 allows bending deformation with a small radius of curvature without torsion, and is less prone to poor force transmission caused by torsion.

[0068] Furthermore, in the torsion resistance test, a torsion test fixture 40 with outer peripheral surfaces of different outer diameters is prepared. The main body 16 is bent and deformed along the outer peripheral surface of the torsion test fixture 40 to confirm whether torsion occurs in the main body 16. Then, the tester sequentially reduces the outer diameter of the torsion test fixture 40 along which the main body 16 is bent, and the outer diameter of the torsion test fixture 40 when torsion occurs in the main body 16 is taken as the test result. Therefore, the smaller the outer diameter of the torsion test fixture 40 as the test result of the torsion resistance test, the less likely torsion caused by bending deformation will occur in the main body 16, and the better the torsion resistance of the main body 16.

[0069] Preferably, the maximum load value measured in the flattening test of the main body portion 16 of the distal rod 12 is 6.0 N or less. By setting the flattening characteristics of the main body portion 16 as described above, the main body portion 16 is more likely to produce flattening deformation (change in cross-sectional shape) relative to loads from the side, and is more likely to produce bending deformation accompanied by the change in cross-sectional shape, thus achieving excellent bending flexibility.

[0070] Furthermore, preferably, the maximum load value measured in the flattening test of the main body portion 16 of the distal rod 12 is 4.0 N or more. This prevents the cross-sectional shape of the main body portion 16 from changing unnecessarily relative to the input, thereby making it easier to maintain the cavity of the distal rod 12. For example, by setting the maximum load value measured in the flattening test of the main body portion 16 to be 4.0 N or more and 6.0 N or less, it is possible to achieve both excellent flexibility of the main body portion 16 relative to bending and maintenance of the cavity of the main body portion 16.

[0071] Furthermore, the flattening test can be performed as follows. First, as... Figure 6 As shown, the tester radially clamped the main body 16 of the distal rod 12 between the support surface 42 and the flattening clamp 44, and applied a load of 0.5 N. Then, the flattening clamp 44 was moved 0.5 mm toward the support surface 42, and the maximum load value when the main body 16 was further flattened radially was measured.

[0072] The proximal rod 14 is made of wire (filament) of metal such as medical-grade stainless steel. A plate-shaped protective member 46 is provided on the base end side of the proximal rod 14 to prevent the operator or others from contacting the base end of the proximal rod 14. The proximal rod 14 can be coated on its outer peripheral surface to improve its sliding properties and corrosion resistance.

[0073] The front end portion of the proximal rod 14 overlaps with the outer peripheral surface of the main body portion 16 of the distal rod 12, and is connected to the main body portion 16 by a connecting tube 48 fixed to the main body portion 16 in an outer sleeve state. The connecting tube 48 is formed of synthetic resin or the like, and for example, it is deformed by heating or other methods while being sleeved on the base end portion of the main body portion 16 over which the front end portion of the proximal rod 14 overlaps. As a result, the connecting tube 48 is tightly fixed to the base end portion of the main body portion 16 of the distal rod 12 and the front end portion of the proximal rod 14. By providing the connecting tube 48 in this way, the base end portion of the main body portion 16 of the distal rod 12 and the front end portion of the proximal rod 14 are fixed to each other by the connecting tube 48, and the front end portion of the proximal rod 14 is connected to the base end portion of the distal rod 12. In this embodiment, the outer layer 22 and the braid 24 of the main body 16 do not reach the base end of the distal rod 12, and the base end of the distal rod 12 is composed of the inner layer 20 and the connecting tube 48. Of course, at least one of the outer layer 22 and the braid 24 may reach the base end of the distal rod 12, and the inner layer 20 may not reach the base end of the distal rod 12.

[0074] Furthermore, the aforementioned connection structure between the proximal rod 14 and the distal rod 12 is merely an example and is not particularly limited. Specifically, for example, the front end portion of the proximal rod 14 may be configured and fixed between the inner layer 20 and the outer layer 22 along a predetermined length of the base end side of the distal rod 12, thereby fixing it to the distal rod 12. In this case, the connecting tube 48 may not be necessary. When the proximal rod 14 is fixed between the inner layer 20 and the outer layer 22, it is preferable that the inner layer 20 and the outer layer 22 constitute the base end of the distal rod 12, and the braid 24 may not reach the base end of the distal rod 12.

[0075] Furthermore, by placing the connecting tube 48 at the base end of the distal rod 12, an anti-slip portion without a coating 28 is provided on the outer peripheral surface of the base end of the distal rod 12 via the connecting tube 48. The coating 28, located on the front end side of the connecting tube 48, is disposed on the outer peripheral surface of the distal rod 12 in a length region extending from the front end of the distal rod 12 toward the base end but not reaching the base end. Compared to the portion in the blood where the coefficient of friction with respect to the blood vessel wall, the guiding catheter 50 (described later), etc., is reduced due to the coating 28, the coefficient of friction of the anti-slip portion in the blood vessel wall, the guiding catheter 50 (described later), etc., is increased. Moreover, by providing the anti-slip portion (connecting tube 48) on the outer peripheral surface of the base end of the distal rod 12, it is possible to prevent the guiding extension catheter 10 from detaching from the guiding catheter 50 (described later) toward the front end side.

[0076] like Figure 7 As shown, the guide extension catheter 10, configured as described above, is inserted into the guide catheter 50 for use. The guide catheter 50 can be a conventionally known guide catheter. The guide catheter 50 has a flexible, cylindrical catheter body 52. ​​The catheter body 52, like the main body portion 16 of the guide extension catheter 10, is formed as a synthetic resin tube with embedded metal reinforcing members (braid). Furthermore, a contrast marker 54, formed to be X-ray impermeable in conjunction with a contrast agent or the like, is provided at the front end of the catheter body 52.

[0077] A Y-connector 56 is provided at the base of the catheter body 52. ​​A check valve (not shown) is provided within the Y-connector 56 to prevent backflow of blood. In addition, the Y-connector 56 is provided with a side arm 58 branching from the main body, through which drugs, contrast agents, etc. can be injected.

[0078] A balloon catheter 60, serving as a treatment catheter, is inserted into the guiding extension catheter 10. The balloon catheter 60 can employ a conventionally known structure, whereby the balloon 62 positioned at its distal end is inflated while inserted through the stenosis 68 of the coronary artery 66 (described later), thereby dilating the stenosis 68 using the balloon 62. Furthermore, the treatment catheter is not limited to the balloon catheter 60 that dilates the stenosis 68 using the balloon 62. Specifically, for example, various known treatment catheters can be used, such as a cutting balloon catheter equipped with a cutting balloon having a blade on its peripheral surface, a stent delivery catheter for placing a stent in the stenosis 68, a plaque resection catheter for removing the stenotic lesion to eliminate the stenosis, and a rotational atherectomy device.

[0079] Furthermore, the catheter assembly 64 comprises a guiding catheter 50, a guiding extension catheter 10, and a balloon catheter 60. In the catheter assembly 64, the guiding extension catheter 10 is inserted into the guiding catheter 50, and the balloon catheter 60 is inserted into the guiding extension catheter 10.

[0080] Such a catheter assembly 64 is used, for example, when dilating a narrowed portion 68 within a coronary artery 66 of the heart via percutaneous transcatheter aortic angioplasty (PTCA). Hereinafter, for reference, an example of the use of the catheter assembly 64 in a procedure via the femoral artery is briefly described.

[0081] First, the practitioner uses a device (not shown) to puncture the patient's femoral artery at point 70. Figure 8 As shown, a sheath 72 is inserted into the femoral artery 70 from the puncture site. The operator inserts a guiding catheter 50, which is inserted into the femoral artery 70 from the sheath 72, into the ascending aorta 74, and positions the tip of the guiding catheter 50 at the entrance of the coronary artery 66.

[0082] Next, the practitioner covers the guide wire 76 with the guide extension catheter 10, which is inserted through the guide catheter 50, so that the distal end of the guide extension catheter 10, after being advanced along the guide wire 76 within the guide catheter 50, protrudes from the distal end of the guide catheter 50. Thus, the distal end 12 is inserted into the coronary artery 66, with its tip positioned proximal to the narrow portion 68 within the coronary artery 66.

[0083] The tip piece 18 constituting the distal end of the distal rod 12 is formed, for example, from a resin mixed with a powder composed of X-ray impermeable materials such as bismuth oxide and tungsten as a contrast agent, forming a marker portion that can be confirmed under X-ray fluoroscopy. Thus, the operator can, for example, confirm the position of the tip piece 18 on a monitor displaying X-ray images while manipulating the guiding extension catheter 10, thereby enabling the guiding extension catheter 10 inserted into the coronary artery to reach the lesion site. In particular, by making the marker portion flexible, the tip of the tip piece 18 can also be used as a marker portion, making fluoroscopy of the distal end of the distal rod 12 possible, which is not possible when using a ring marker.

[0084] The operator then inserts the balloon catheter 60, which is fitted with guide wire 76, into the distal stem 12 of the guiding extension catheter 10. The balloon 62, positioned on the balloon catheter 60, is then protruded distal to the distal stem 12 and delivered to the stenosis 68. The balloon 62 inserted into the stenosis 68 inflates within the circumference of the stenosis 68, thereby dilating the stenosis 68 and restoring blood flow to the coronary artery 66. The guide wire 76 used for inserting the balloon catheter 60 may be different from the guide wire used for inserting the guiding extension catheter 10. For example, after the guiding extension catheter 10 has been inserted and connected to the guiding catheter 50, the balloon catheter 60 may be inserted and connected to the guiding extension catheter 10 instead of the thinner guide wire 76.

[0085] The distal end of the distal stem 12 located within the guiding catheter 50 has an anti-slip portion on its outer peripheral surface based on the connecting tube 48. This increases the frictional resistance between the distal end of the guiding extension catheter 10 and the guiding catheter 50, thus positioning the guiding extension catheter 10 relative to the guiding catheter 50. Therefore, for example, it can prevent the guiding extension catheter 10 from dislodging from the guiding catheter 50 towards the anterior end. Furthermore, for example, when the balloon catheter 60, protruding from the guiding extension catheter 10 towards the anterior end, comes into contact with a stenotic lesion or other vascular condition and exerts a force towards the distal end, it can prevent the guiding extension catheter 10 from being pushed back into the guiding catheter 50 by the reaction force of the balloon catheter 60. Moreover, the connecting tube 48 constituting the anti-slip portion does not necessarily need to be entirely located within the guiding catheter 50; for example, its anterior end may protrude distally from the guiding catheter 50.

[0086] The above describes an example of using catheter assembly 64 in surgery via the femoral artery approach, but catheter assembly 64 can also be used, for example, in surgeries via the radial artery approach or the brachial artery approach. Furthermore, in Figure 8 The example shown illustrates a procedure for a stenosis 68 in the left anterior descending artery (66L), but the catheter assembly 64 can also be used for procedures such as those for lesions in the circumflex branch of the left coronary artery (66L) or the right coronary artery (66R). Furthermore, the method of using the guiding extension catheter 10, which includes the illustrated procedure (the sequence of insertion and removal of each catheter and guidewire, etc.), is merely an example and is not particularly limited. In addition, in Figure 8 In the diagram, for ease of observation, the vascular system is schematically shown with the descending aorta and other arteries depicted in a position that does not overlap with the coronary arteries 66.

[0087] The guiding extension catheter 10 protrudes from the tip of the guiding catheter 50 disposed at the inlet of the coronary artery 66 and is inserted into the coronary artery 66 up to the proximal end of the stenosis 68, thereby guiding the therapeutic catheter such as the balloon catheter 60 to the stenosis 68. Therefore, in order to perform treatment even when the stenosis 68 is far from the inlet of the coronary artery 66, a guiding extension catheter 10 capable of reaching a more distal position in the coronary artery 66 is required. Therefore, compared to conventional guiding extension catheters, the guiding extension catheter 10 configured according to the present invention can be inserted to a more distal position in the coronary artery 66.

[0088] That is, in the guiding extension catheter 10, the maximum load value measured by the aforementioned three-point bending test is 0.1N or more and 0.6N or less, and the length of the tip piece 18 is 2.5mm or more. Furthermore, the tip piece 18 has a soft marking portion incorporating X-ray impermeable powder, thus eliminating the need for a rigid annular marking. As a result, the guiding extension catheter 10 achieves excellent permeability, allowing insertion to a more distal position relative to the coronary artery 66.

[0089] This is evident from the results of a follow-up test of the guiding extension catheter relative to a simulated coronary artery 66. That is, as... Figure 9 As shown, a test device was prepared with a cavity inside that corresponds to a blood vessel such as the coronary artery 66. A guide extension catheter was inserted into the cavity corresponding to the coronary artery 66 at a speed of 500 mm / min, thereby confirming the followability (passability) of the guide extension catheter relative to the coronary artery 66.

[0090] In the following description, Examples 1 to 6 are the guiding extension catheters according to the present invention, Comparative Examples 1 to 5 are guiding extension catheters with conventional structures, and Comparative Example 6 is an example in which a rigid annular contrast marker (ring mark) is installed on the guiding extension catheter of Example 3, thereby shortening the substantial length of the front end piece. Furthermore, in Figures 10 to 13 below, the guiding extension catheters of Examples 1 to 6 are labeled with reference numerals corresponding to the guiding extension catheter 10 of the above-described embodiments, and the guiding extension catheters of Comparative Examples 1 to 6 are labeled with reference numerals for guiding extension catheter 10', distal rod 12', and main body portion 16'. Moreover, Examples 1 to 6 are all guiding extension catheters 10 according to the present invention, but they differ in forming materials, structures, etc. For example, the distribution of bending stiffness in the length direction of the main body portion 16 differs.

[0091] Figure 10 shows the results of a follow-up test of the guiding extension catheter relative to the left anterior descending artery (LEA) at 66L. Figure 10A The distal end of the guiding extension catheter 10 in Examples 1 to 6, indicated by arrows, all reached a position higher than that indicated by arrows. Figure 10B The arrows indicate the distal positions of any of the guiding extension catheters 10' in Comparative Examples 1 to 4. Furthermore, in the follow-up test relative to the left anterior descending branch of the left coronary artery 66L, the tips of the guiding extension catheters 10' in Comparative Examples 5 and 6 reached approximately the same position as the tips of the guiding extension catheters 10' in Examples 1 to 3, showing superior follow-up compared to Comparative Examples 1 to 4. However, Examples 4 to 6 showed superior follow-up, reaching even more distal positions than Comparative Examples 5 and 6. Thus, experiments confirm that the guiding extension catheter 10 according to the present invention can reach more distal positions during insertion into the left anterior descending branch of the left coronary artery 66L.

[0092] Figure 11 shows the results of a follow-up test of the guiding extension catheter relative to the left circumflex branch of the left coronary artery 66L. Figure 11A The distal end of the guiding extension catheter 10 in Examples 1 to 6, indicated by arrows, all reached a position higher than that indicated by arrows. Figure 11B The arrows indicate the distal positions of any of the guiding extension catheters 10' in Comparative Examples 1 to 6. Thus, experiments have confirmed that the guiding extension catheter 10 of the embodiments of the present invention exhibits extremely superior tracking performance compared to the comparative examples during insertion into the left circumflex branch of the left coronary artery 66L, and can reach more distal positions.

[0093] Figure 12 shows the results of a follow-up trial of the guiding extension catheter relative to the right coronary artery 66R1. Figure 12A The distal end of the guiding extension catheter 10 in Examples 1 to 6, indicated by arrows, all reached a position higher than that indicated by arrows. Figure 12B The guiding extension catheters 10' of Comparative Examples 1 to 5, indicated by arrows, are all positioned significantly distally. Furthermore, in the follow-up test relative to the right coronary artery 66R1, the tip of the guiding extension catheter 10' of Comparative Example 6 reached approximately the same position as the tip of the guiding extension catheters 10 of Examples 2 and 3, demonstrating superior follow-up compared to Comparative Examples 1 to 5. However, Examples 1, 4 to 6 showed superior follow-up by reaching even more distal positions compared to Comparative Example 6. Thus, experiments confirm that the guiding extension catheter 10 according to the present invention can reach more distal positions during insertion into the right coronary artery 66R1. Moreover, compared to the right coronary artery 66R2 described later, the proximal portion of the right coronary artery 66R1 is elevated.

[0094] Figure 13 shows the results of a follow-up trial of the guiding extension catheter relative to the right coronary artery 66R2. Figure 13A The distal end of the guiding extension catheter 10 in Examples 1 to 6, indicated by arrows, all reached a position higher than that indicated by arrows. Figure 13B The arrows indicate the distal positions of any of the guiding extension catheters 10' in Comparative Examples 1 to 5. Thus, experiments confirm that the guiding extension catheter 10 according to the present invention can reach a more distal position during insertion into the right coronary artery 66R2. Furthermore, in the follow-up test into the right coronary artery 66R1, the tip of the guiding extension catheter 10' in Comparative Example 6 reached approximately the same position as the tip of the guiding extension catheters 10 in Examples 1 and 3, showing excellent follow-up compared to Comparative Examples 1 to 5. However, Examples 2, 4 to 6 showed superior follow-up compared to Comparative Example 6, being able to reach even more distal positions.

[0095] As described above, the guiding extension catheters 10 of Embodiments 1 to 6 of the present invention have superior following ability to the coronary artery 66 compared with the guiding extension catheters 10' of Comparative Examples 1 to 6 of the prior art, and can be expected to reach a more distant position of the coronary artery 66.

[0096] exist Figures 14-18 The results of various characteristic tests of the guide extension catheter 10 of the embodiment and the guide extension catheter 10' of the comparative example are shown.

[0097] Figure 14The results of the three-point bending test of the distal rod were performed on Examples 1 to 6 and Comparative Examples 1 to 6. As a result, the maximum load value of Examples 1 to 6 was less than 0.6 N, while the maximum load value of Comparative Examples 1 to 5 was greater than 0.6 N. From these test results, it can be seen that the main body portion 16 of the distal rod 12 of Examples 1 to 6 possesses flexibility capable of bending with a smaller force than the main body portion 16' of the distal rod 12' of Comparative Examples 1 to 5. Therefore, it can be considered that the main body portion 16 of the distal rod 12 exhibits excellent following of the bending of the coronary artery 66. Furthermore, the results of the three-point bending test of Comparative Example 6 were similar to those of Examples 1 to 6, but as described above, it was confirmed that the following of the coronary artery 66 was worse than that of Examples 1 to 6, clarifying that good following is not necessarily achieved simply by making the distal rod 12 flexible.

[0098] In addition, the maximum load value of the distal rod 12 in the three-point bending test of Examples 1 to 6 is all above 0.1N, which also ensures the degree of stiffness required for the distal rod 12 to achieve the pushability, etc.

[0099] Figure 15 The results are based on measurements of the length of the front end piece in Examples 1 to 6 and Comparative Examples 1 to 6. It can be seen that the front end piece 18 of Examples 1 to 6 is approximately 4.5 mm long, while the front end pieces of Comparative Examples 1 to 6 are all approximately 1 to 2 mm long. Examples 1 to 6 have front end pieces that are longer than those of Comparative Examples 1 to 6. Therefore, when the distal rod 12 is inserted into the curved coronary artery 66, the orientation of the flexible front end portion 26 of the distal rod 12 with the long front end piece 18 quickly changes to the direction along the coronary artery 66, thus improving the tracking ability of the coronary artery 66.

[0100] Furthermore, the presence or absence of the annular mark differs between Example 3 and Comparative Example 6. Comparative Example 6 is equipped with an annular mark compared to Example 3, thereby shortening the length of the front end piece 18. It was confirmed that there is a significant difference in the tracking performance of Example 3 and Comparative Example 6 towards the left circumflex branch of the left coronary artery 66L, with Example 3 exhibiting superior tracking performance compared to Comparative Example 6 (see Figure 11). Therefore, it is believed that the use of a soft mark portion—incorporating powder of an X-ray impermeable material into the resin material forming the front end piece 18, rather than a conventionally known rigid annular mark, and the placement of this soft portion in the front end portion 26 of the distal rod 12 in a region long from the front end, is also a reason for the improved tracking performance of the guiding extension catheter 10 towards the coronary artery 66.

[0101] Furthermore, Figure 16The results are from a flexibility test of the distal end portion of the distal rod performed on Examples 1 to 6 and Comparative Examples 1 to 6. As a result, the maximum load values ​​of Examples 1 to 5 are all below 1.5 N, while the maximum load value of Example 6 is greater than 2.0 N. In Example 6, compared to Example 4, which is formed according to the above-described embodiment, the structure in Example 6, where the inner layer 20 made of polytetrafluoroethylene (PTFE) extends to the entire distal rod 12 up to the front end of the distal end piece 18, results in lower flexibility of the distal end portion compared to Example 4. Furthermore, Examples 4 and 6... Figures 10A to 12A The follow-up tests shown exhibited the same degree of follow-up, but... Figure 13A In the follow-up test of the right coronary artery 66R2 shown, Example 4 was able to be inserted to a more distal position than Example 6, and Example 4 showed superior follow-up compared to Example 6.

[0102] Furthermore, the distal end portion 26 of the distal rod 12 in Examples 1 to 5 is more flexible in terms of axial compression than the distal end portion of the distal rod 12' in Comparative Examples 1 to 3. Therefore, in Examples 1 to 5, when the distal end portion 26 of the distal rod 12 abuts against the inner wall surface of the coronary artery 66, the distal end portion 26, including the distal end piece 18, is more prone to deformation than the main body portion 16 of the distal rod 12, and the distal end portion 26 of the distal rod 12 is more likely to change orientation along the direction of the coronary artery 66. Furthermore, when the distal end portion 26 of the distal rod 12 contacts the coronary artery 66, damage to the coronary artery 66 by the distal rod 12 can be prevented. In addition, the maximum load value in the flexibility test of the distal end portion 26 of the distal rod 12 is preferably 1.3N or more and 1.5N or less.

[0103] Figure 17 The results are from the torsion resistance tests conducted on the distal rods of Examples 1-3 and Comparative Examples 1-3. As a result, the distal rods 12 of Examples 1-3 were all torn along the outer peripheral surface of the torsion test fixture 40 with an outer diameter of 2.0 mm. In contrast, the distal rods 12' of Comparative Examples 2 and 3 were torn along the outer peripheral surface of the torsion test fixture 40 with an outer diameter of 4.0 mm. Therefore, compared to the distal rods 12' of Comparative Examples 2 and 3, the distal rods 12 of Examples 1-3 are less prone to torsion before bending with a small curvature, and the adverse effects of torsion on pushing performance are easily avoided.

[0104] Figure 18The results are from the flattening tests performed on the distal rods of Examples 1 to 3 and Comparative Examples 1 to 3. It can be seen that the maximum load values ​​of Examples 1 to 3 are all above 4.0 N, sufficiently ensuring the radial shape maintenance performance required for the highly flexible distal rod 12. Furthermore, the maximum load values ​​of Examples 1 to 3 are all below 6.0 N, while the maximum load values ​​of Comparative Examples 1 and 3 are both above 6.0 N. Compared to the distal rods 12' of Comparative Examples 1 and 3, the main body portion 16 of the distal rods 12 of Examples 1 to 3 is more prone to changes in cross-sectional shape due to external forces, and more easily allows for bending deformation accompanying changes in cross-sectional shape.

[0105] The embodiments of the present invention have been described in detail above, but the present invention is not limited to these specific descriptions. For example, in the above embodiments, the main body portion 16 of the distal rod 12 is formed with a braided body 24 disposed between the inner layer 20 and the outer layer 22, but the main body portion 16 may also be formed entirely of a synthetic resin material. In addition, the front end piece 18 disposed in the distal rod 12 at a position closer to the front end than the main body portion 16 may be integrally formed of the same synthetic resin material as the main body portion 16, or it may be formed of a different material from the main body portion 16 and fixed by methods such as welding.

[0106] Explanation of reference numerals in the attached figures

[0107] 10, 10': Guiding extension catheter;

[0108] 12, 12': Far end rod;

[0109] 14: Proximal end rod;

[0110] 16, 16': Main body;

[0111] 18: Front end piece (marking section);

[0112] 20: Inner layer;

[0113] 22: Outer layer;

[0114] 24: Woven body;

[0115] 26: Front-end section;

[0116] 28: Coating;

[0117] 30: Support platform;

[0118] 32: fulcrum;

[0119] 34: Pressure head;

[0120] 36: Hold the clamp;

[0121] 38: Pressing clamp;

[0122] 40: Torsion test fixture;

[0123] 42: Support surface;

[0124] 44: Flattening clamp;

[0125] 46: Protective components;

[0126] 48: Connecting pipe;

[0127] 50: Guiding catheter;

[0128] 52: Catheter body;

[0129] 54: Imaging markers;

[0130] 56: Y connector;

[0131] 58: Side arm;

[0132] 60: Balloon catheter;

[0133] 62: Balloon;

[0134] 64: Catheter assembly;

[0135] 66: Coronary artery;

[0136] 68: Narrow section;

[0137] 70: Femoral artery;

[0138] 72: Sheath;

[0139] 74: Ascending aorta;

[0140] 76: Guide wire.

Claims

1. A guiding and extending catheter, comprising a tubular distal rod disposed at the anterior end of a proximal rod, wherein, Regarding the main body of the distal rod, the main body is placed on a support platform of a three-point bending test fixture with a distance of 15 mm between the fulcrums. At the center of the support platform between the fulcrums, a pressure head that moves relative to the support platform at a relative speed of 10 mm / min presses against the main body from the side, thereby deforming the main body until it twists. The maximum load acting on the main body is 0.1 N or more and 0.6 N or less. A front end piece, which is more flexible than the main body, is provided on the distal end of the rod at a position closer to the front end than the main body. At the base end of the distal rod, an anti-slip part with a larger coefficient of friction than the front end is provided on the outer peripheral surface.

2. The guide extension catheter of claim 1, wherein, A coating formed of a hydrophilic polymer is provided on the outer peripheral surface of the distal rod in a length region extending from the front end of the distal rod toward the base end but not reaching the base end.

3. The guide extension catheter of claim 1 or 2, wherein, Regarding the main body portion of the distal rod, the outer diameter of the torsion test fixture, which generates the torsion by being wound around the outer circumferential surface of the cylindrical shape, is 3 mm or less.

4. The guide extension catheter of claim 1 or 2, wherein, Regarding the main body portion of the distal rod, the maximum load value is 4.0N or more when the flattening clamp is further pressed 0.5mm toward the support surface from a state where it is radially clamped between the support surface and the flattening clamp and a load of 0.5N is applied.

5. The guide extension catheter of claim 1 or 2, wherein, Regarding the front end piece, when the front end face of the front end piece is in contact with the pressing clamp by constraining the distal rod connected to the front end piece at a position offset from the front end to the base end side by a portion 5 mm from the front end, and the pressing clamp is moved close relative to the pressing clamp at a pressing speed of 10 mm / min, the maximum load value when the front end piece is compressed by 1 mm along the length direction is 0.5 N or more and 1.5 N or less.

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