JP5154188B2 - Balloon catheter - Google Patents

Description

  The present invention is mainly used for percutaneous angioplasty (PTA, PTCA, etc.), expands a stenosis or occlusion in a blood vessel such as a coronary artery with a balloon, and reconstructs blood circulation on the peripheral side thereof. About.

  In general, in PTCA (percutaneous coronary angioplasty), a small-sized guiding catheter is first inserted into the femoral artery or the radial artery, and the distal end of the guiding catheter extends from the femoral artery to the thoracic aorta or radial artery. Push in via the brachial artery until it reaches the entrance of the coronary artery. The guide wire is then inserted through the guiding catheter and further introduced into the lumen of the coronary artery and advanced until the distal end of the guide wire crosses the stenosis of the coronary artery. Next, the balloon catheter is inserted into the guiding catheter, and further advanced along the guide wire, so that the balloon provided at the distal end of the balloon catheter is positioned over the entire stenosis. Then, the lumen wall of the stenosis is expanded by supplying a high-pressure fluid into the balloon to expand the balloon, and the blood flow in the coronary artery is reconstructed.

  Various physical properties are required for the shaft of a balloon catheter used for angioplasty such as PTCA. For example, it needs to be formed thin so as to have an inner diameter capable of securing a flow path for high-pressure fluid and an outer diameter capable of moving without causing large friction in a lumen such as a guiding catheter. Therefore, it is required to secure pressure resistance against the fluid pressure during balloon expansion. Furthermore, flexibility for ensuring trackability and rigidity for ensuring kink-resistance and pushability are required at the same time.

  Various configurations for improving the physical properties of the shaft have been proposed.

  In general, a conventional balloon catheter is configured by a flexible polymer tube, for example, as described in Patent Document 1, a shaft composed of a tube having high rigidity such as a metal tube is disposed on the proximal side. A basic configuration is adopted in which the shaft is arranged on the distal side and these are interconnected. With this basic configuration, both trackability and pushability are achieved.

  In the above basic configuration, the rigidity changes suddenly at the connection portion between the proximal shaft and the distal shaft. For this reason, the balloon catheter described in Patent Document 1 is configured such that a portion including the sudden stiffness change portion and extending with a certain length has intermediate rigidity between these two shafts. Sudden changes in rigidity are alleviated to ensure kink resistance.

  Further, in Patent Document 2, for example, in the above basic configuration, an intermediate portion made of a polymer tube is provided between two shafts, the distal end portion of the proximal shaft is intruded into the intermediate portion, and the distal end portion into which the intrusion is further spiraled. A slit is formed to thereby alleviate sudden change in rigidity at the shaft connecting portion and secure kink resistance.

  For example, in Patent Document 3, in the above basic configuration, the distal end of the proximal shaft is made lower in rigidity than the other portions, and the distal end with the low rigidity inserted into the distal shaft is distal. The proximal end of the side shaft is joined to the proximal shaft, thereby alleviating sudden changes in rigidity at the shaft connecting portion and ensuring kink resistance.

  Further, for example, in Patent Document 4, in the above basic configuration, the distal end portion of the proximal shaft is cut obliquely, and the obliquely cut distal end portion is fitted into the distal shaft to connect these two shafts. Thus, the rigidity of the shaft connecting portion is alleviated and kink resistance is secured.

Further, for example, in Patent Document 5, a configuration different from that of Patent Documents 1 to 4 is adopted with respect to the proximal shaft, and the proximal shaft is configured by inserting a helically twisted metal wire into the polymer tube. Thus, both the rigidity and flexibility of the proximal shaft are achieved.
Japanese Patent Publication No. 6-507105 Japanese Patent No. 39091991 JP 2002-253678 A JP 2003-164528 A JP 2002-78802 A

  However, the conventional balloon catheter still has the following problems regarding physical properties.

  Regarding the balloon catheters of Patent Documents 1 to 4, although the sudden rigidity change in the shaft connecting portion is alleviated, the intermediate rigid portion having intermediate rigidity between the proximal shaft and the distal shaft is only in the vicinity of the shaft connecting portion. Since it extends with a certain length, it is difficult to reach a point where the sudden change in rigidity is resolved. Further, since the proximal shaft is a structure having the shape of a metal tube, that is, a tube itself made of metal, it has a uniform rigidity over substantially the entire length except for the vicinity of the shaft connecting portion. Therefore, stress applied at the time of bending is concentrated in the vicinity of the shaft connecting portion where the rigidity changes, so that there is a certain limit in securing kink resistance.

  Moreover, since the shaft on the proximal side is a single metal tube, it has low viscoelasticity, and rebounds in strength due to elastic force when bent. For this reason, at the time of use, the resistance force to the force which pushes in a shaft becomes large and affects operativity. In addition, when the balloon catheter is not used, it is not possible to easily perform the work of winding and binding the shaft when storing the balloon catheter.

  Regarding the balloon catheter of Patent Document 5, since the rigidity is reinforced by a metal wire while ensuring flexibility with a polymer tube in the proximal shaft, the operability at the time of use described above with respect to Patent Documents 1 to 4 and There is a possibility of improvement in terms of ease of work when not in use. However, this rigidity reinforcement improves only pushability and kink resistance, and does not improve pressure resistance against high-pressure fluid. For this reason, in order to ensure the pressure resistance comparable to the case where the metal tube itself is used as the proximal shaft, the polymer tube has to be formed with a considerably large thickness.

  The present invention has been made in view of such points, and ensures a gentle rigidity inclination over the entire length of the shaft, thereby providing good crushing strength, pressure resistance and kink resistance without forming the shaft to be extremely thick. An object of the present invention is to provide a balloon catheter that can be secured.

The balloon catheter of the present invention includes a proxy shaft having a first polymer tube extending from a proximal end to a distal end, and further extending further distally from the distal end of the first polymer tube. A distal shaft including a second polymer tube, and the proxy shaft includes a metal material that covers the entire inner peripheral surface of the first polymer tube from the proximal end to the distal end. A covering portion that reinforces the rigidity of the proximal shaft and continuously extends from the proximal end to the distal end over the entire length of the covering portion from the proximal end to the distal end. A configuration is adopted in which a metal reinforcing body is provided that has a slit portion that is formed in a spiral shape with a decreasing pitch width and that adjusts the rigid reinforcement.

  According to the present invention, it is possible to ensure a gentle rigidity inclination over the entire length of the shaft, thereby ensuring good crushing strength, pressure resistance, and kink resistance without forming the shaft extremely thick.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an external view showing a configuration of a balloon catheter according to an embodiment of the present invention.

  In FIG. 1, the balloon catheter 1 has a hub 10, a proximal shaft 20, a distal shaft 30, a balloon 40, and a guide wire lumen tube 50 as main bodies.

  The hub 10 is arranged at the hand of a doctor who operates the balloon catheter 1 in angioplasty. The hub 10 is configured to be connectable to a pressure application device (not shown) such as an inflator that supplies a high-pressure fluid. The proximal shaft 20 is a characteristic part of the balloon catheter 1 and is joined to the hub 10 so as to be in fluid communication, and extends to the distal side. Further, the distal shaft 30 is joined to the distal side so as to be in fluid communication. Has been. A balloon 40 is joined to the distal side of the distal shaft 30. The proxy shaft 20 and the distal shaft 30 form a flow path for supplying high-pressure fluid into the balloon 40. The distal end of the balloon 40 surrounds the outer peripheral surface of the guide wire lumen tube 50 and is joined to the outer peripheral surface. Thereby, the high-pressure fluid supplied to the balloon 40 stays inside the balloon 40, and the balloon 40 expands.

  The guide wire lumen tube 50 penetrates the distal shaft 30 so that its lumen (guide wire lumen) forms a coaxial or biaxial double tube structure with the distal shaft 30 without communicating with the flow path. It is provided through the balloon 40. The opening on the proximal side of the guide wire lumen tube 50 is disposed in the vicinity of the joint between the proxy shaft 20 and the distal shaft 30, and the opening on the distal side of the guide wire lumen tube 50 is the tip of the balloon 40. It is arranged further to the distal side than the part. The proximal opening is provided as a guide wire port 60 that is an insertion / extraction opening for the guide wire 70.

  The length of each part in the main body is not limited to a specific value, but as an example, the length of the balloon 40 is about 10 mm to about 30 mm. The length of the proximal shaft 20 is about 1000 mm, and the length from the proximal end of the proximal shaft 20 to the distal end of the guidewire lumen tube 50 is about 1400 mm. The length of the guide wire lumen tube 50 protruding from the distal end of the balloon 40 is several mm.

  The guide wire 70 is a metal wire having a diameter (for example, about 0.3 mm) that can be inserted into and removed from the guide wire lumen tube 50. In use, the guidewire 70 is inserted into the guidewire lumen tube 50 such that its tip projects from the distal opening of the guidewire lumen tube 50. The guide wire 70 has a sufficient length that can guide the balloon catheter 1 until the balloon 40 reaches the stenosis when the balloon catheter 1 is pushed by a catheter insertion procedure in angioplasty.

  The insertion depth marker 80 is different from the most distal portion of the balloon catheter 1 (distal end of the guide wire lumen tube 50) at 900 mm and 1000 mm so that it can be easily distinguished from other parts on the outer peripheral surface of the proximal shaft 20. It is arranged in color and has a function as a display body indicating the insertion depth of the balloon catheter 1 into the guiding catheter during the catheter insertion procedure. That is, taking the case where the balloon catheter 1 is used in combination with a guiding catheter having a length of 1000 mm as an example, the balloon catheter 1 is inserted into the guiding catheter from its most distal end, and an insertion depth marker 80 at a position of 1000 mm is provided. Until positioned at the proximal end of the guiding catheter, the physician can easily recognize that the leading edge of the balloon catheter 1 has not yet protruded from the distal opening of the guiding catheter. The position and number of insertion depth markers 80 are not limited to those described above, and can be implemented with various changes.

  The balloon marker 90 is formed by winding a member such as a coil or a ring made of a radiopaque material around a part on the outer peripheral surface of the guide wire lumen tube 50 in the balloon 40. Yes, it can be used when positioning the balloon 40 under fluoroscopy.

  Here, the configuration of the main body of the balloon catheter 1 will be described in more detail with reference to FIG. FIG. 2 is a fragmentary cross-sectional view showing the structure of a portion of the balloon catheter 1 that is broken and enlarged.

  The proxy shaft 20 includes a polymer tube 23. The polymer tube 23 is made of a flexible polymer material, and has, for example, a tube structure having an outer diameter of about 0.7 mm and a thickness of about 0.03 to 0.05 mm (that is, a structure having the shape of the tube itself). And extends from the proximal end 21 to the distal end 22. Examples of the material constituting the polymer tube 23 include polyamide, polyamide elastomer, fluorine resin, polyimide, PEEK (polyether ether ketone), polyethylene terephthalate, polyethylene, polyurethane, and the like. A material formed by combining these may be used. Moreover, you may use what integrated the fine metal braided wire (blade wire) in these materials.

  The proxy shaft 20 further includes a metal reinforcing body 24. The metal reinforcing body 24 is made of a metal material such as SUS (stainless steel) having rigidity higher than that of the polymer material constituting the polymer tube 23 and is fitted into the polymer tube 23. The metal reinforcing body 24 is not a tube structure, but a spiral structure (coil body) having a wall portion that extends in a spiral shape while maintaining a constant diameter and thereby has a circular section in the longitudinal direction. .

  More specifically, the metal reinforcing body 24 is brought into close contact with the inner peripheral surface of the polymer tube 23 by the covering surface 25 (that is, the outer surface of the wall portion) as a covering portion, and this is connected from the proximal end 21 to the distal end. The entire length up to 22 is covered to reinforce the rigidity of the proxy shaft 20. That is, in the case where the proxy shaft 20 is constituted only by the polymer tube 23, the metal reinforcement 24 is attached where sufficient kink resistance and pushability cannot be ensured unless the polymer tube 23 is formed with a considerable thickness. Thus, sufficient kink resistance and pushability can be ensured while the polymer tube 23 is formed thin. Furthermore, since the metal reinforcing body 25 has a surface (covering surface 25) for covering the polymer tube 23 as means for reinforcing rigidity, the metal reinforcing body 25 is simply twisted in a spiral shape and attached to the polymer tube 23. The pressure resistance against high-pressure fluid can be improved, and the polymer tube 23 can be further thinned.

  A spiral slit 26 is formed in a spiral shape over the entire length from the proximal end 21 to the distal end 22 on the covering surface 25 of the metal reinforcing body 24, and a proximal shaft is formed by a formation portion (slit portion) of the spiral slit 26. The degree to which the rigidity of 20 is reinforced is adjusted. Since the spiral slit 26 is formed with a pitch width that decreases in the direction from the proximal end 21 to the distal end 22, the degree of reinforcement is reduced in the direction from the proximal end 21 to the distal end 22. The configuration of the spiral slit 26 will be described in detail later.

  The metal reinforcing body 24 having the above configuration can be formed by, for example, cutting a metal tube into a spiral shape by laser processing. In this case, the pitch width near the proximal end 21 is set to 100 mm at the maximum and the pitch width near the distal end 22 is set to the minimum at 0.2 mm, and the spiral slit 26 is configured. The width of the cut to be determined is set to take a constant value in the range of 0.01 mm to 0.1 mm.

  In the present embodiment, the metal reinforcing body 24 is fitted into the polymer tube 23 to cover the inner peripheral surface of the polymer tube 23 with the covering surface 25, but the metal reinforcing body 24 is fitted to the polymer tube 23. By doing so, you may make it coat | cover the outer peripheral surface of the polymer tube 23 with the inner surface of the wall part of a metal reinforcement body. When the metal reinforcing body 24 is externally fitted, the pressure resistance of the proxy shaft 20 can be further improved, which can contribute to further thinning of the polymer tube 23. On the other hand, in this case, as with many existing balloon catheters that use a metal tube as a proximal shaft, the metal material is exposed to the outside, so a special process to improve the slip of the proximal shaft when pushed in. It is preferable to apply (for example, Teflon (registered trademark) coating) to the metal. On the other hand, in the present embodiment, as described above, the metal reinforcing body 24 is internally fitted to cover the inner peripheral surface of the polymer tube 23 and expose the outer peripheral surface to the outside. Can be eliminated. Furthermore, good antithrombogenicity can be maintained.

  The distal shaft 30 includes a polymer tube 32. The polymer tube 32 is a tube structure made of a polymer material like the polymer tube 23 and having an outer diameter of about 0.9 mm and a thickness of about 0.05 mm, for example. The distal shaft 30 is joined at a proximal portion thereof to a portion including the distal end 22 of the proximal shaft 20 by an adhesive or welding, and a distal end located further on the distal side from the distal end 22. It extends to 31.

  In the present embodiment, no means for reinforcing the rigidity of the distal shaft 30 is provided, but an extremely fine metal wire may be mounted on the inner peripheral surface of the polymer tube 32. In this case, the distal end of the metal reinforcing body 24 is formed so that the tongue protrudes from the distal end 22 by several mm to several tens of mm, and a metal wire is welded to the tongue. In addition, a metal wire as a rigidity reinforcing means can be provided in the distal shaft 30.

  In the present embodiment, the case where the polymer tube 23 of the proxy shaft 20 and the polymer tube 32 of the distal shaft 30 are joined by an adhesive or welding is described as an example. However, the polymer tube 23 and the polymer tube 32 are described. And may be integrally formed in advance. That is, a polymer tube extending from the proximal end 21 to the distal end 31 may be used.

  The balloon 40 is formed of a polymer material and can be expanded and contracted by supplying and discharging a high-pressure fluid to the inside. The outer diameter of the balloon 40 when it is contracted (non-expanded) is, for example, about 0.5 to 1.0 mm, and the outer diameter of the balloon 40 when it expands depends on the fluid pressure and the balloon mold size. Different.

  The guide wire lumen tube 50 is made of a polymer material like the polymer tubes 23 and 32, and is, for example, a tube structure having an outer diameter of about 0.6 mm and a thickness of about 0.1 mm. Since the lumen (guide wire lumen) is for inserting the guide wire 70, it does not communicate with the flow path of the high-pressure fluid. Therefore, the distal shaft 30 has a double tube structure in which the guide wire lumen tube 50 is an inner tube and the polymer tube 32 is an outer tube. Here, the double tube structure may be a coaxial type or a biaxial type. The distal end of the guide wire lumen tube 50 is disposed so as to protrude further distally from the distal end of the balloon 40, and constitutes the most distal portion of the balloon catheter 1, that is, the tip 51.

  Next, the pitch width of the spiral slit 26 will be described in more detail with reference to FIG.

  The spiral slit 26 is formed over the entire length from the proximal end 21 to the distal end 22 and has a pitch width that decreases in the direction from the proximal end 21 to the distal end 22. This makes it possible to avoid stress during bending from concentrating on the distal end 22, i.e., there is no longer a sudden change in stiffness near the distal end 22. There is no need to extend a portion having the intermediate rigidity between the proxy shaft 20 and the distal shaft 30 with a certain length in the vicinity.

  Further, the pitch width of the spiral slit 26 decreases continuously from the proximal end 21 to the distal end 22. Thereby, compared with the case where the pitch width is reduced discontinuously, the proxy shaft 20 can be bent smoothly, so that good trackability and operability can be ensured.

  The pitch width is at least a position closer to the insertion depth marker 80 (an insertion depth marker 80a formed at a position of 900 mm from the chip 51 and an insertion depth marker 80b formed at a position of 1000 mm from the chip 51). By continuously decreasing between the distal end 22 and the distal end 22, good trackability and operability can be ensured as described above.

Here, the degree of pitch width reduction, that is, the degree to which the pitch width decreases in the direction from the proximal end 21 to the distal end 22 will be described. Since the pitch width reduction degree of the spiral slit 26 can be variously changed and set according to the use and the demand from the user, various forms can be taken. In the example shown in FIG. 3, different pitch in the second region of the first region of the distal side of the pitch boundary 27 located in the vicinity just apart from the insertion depth marker 80b distance D ₁ from the chip 51 and the proximal side Width reduction degrees P ₁ and P ₂ are set. More specifically, in the first region takes the low pitch reduction of P _1, such as pitch width is very slowly reduced, the pitch width of the second region is the first region more slowly and become not such a high pitch width take a decrease in the degree of _{P 2.} Note that the number and position of the pitch width boundary portions 27 are not limited to one place and the vicinity of the insertion depth marker 80b, and may be a plurality of positions or positions closer to the distal side or the distal side than the insertion depth marker 80b. . Further, the change in the pitch width reduction degree at the pitch width boundary portion 27 is preferably smooth so as not to cause a step change in rigidity (curves B and C in FIG. 4). Although the case where the pitch width changes at a specific position has been described as an example in FIG. 3, the pitch width is reduced so that the pitch width reduction degree is substantially uniform over the entire length of the proxy shaft 20 as shown by the curve A in FIG. There may also be a form of setting. Further, the pitch width reducing degree P ₁ in FIG. 3 has been described taking the case lower than the pitch width reduction of P _2, and vice versa.

  As described above, according to the present embodiment, the proxy shaft is configured by attaching a metal reinforcement to the polymer tube constituting the proxy shaft, and the proxy shaft includes the polymer tube. A covering portion formed of a metallic material for covering from the proximal end to the distal end and reinforcing the rigidity of the proximal shaft, and from the proximal end to the distal end in the covering portion, from the proximal end to the distal end And a spiral slit that is formed in a spiral shape with a pitch width that decreases to a minimum, and that adjusts the reinforcement of the rigidity of the proximal shaft. That is, due to the decrease in the pitch width of the spiral slit provided over the entire length of the covering portion, there is no gentle step change in rigidity over the entire length of the proximal shaft and thus the entire shaft including the proximal shaft and the distal shaft. Can ensure a stable inclination. Therefore, it is possible to avoid stress during bending from concentrating on the connecting portion between the proximal shaft and the distal shaft, and to ensure kink resistance without forming an intermediate rigid portion with a certain length at the connecting portion. it can. In addition, by attaching the metal reinforcement body of the spiral structure to the polymer tube of the pipe structure body, a certain viscoelasticity can be given to the proxy shaft. Therefore, in use, the resistance to the force for pushing the shaft can be reduced, and the operability can be improved. Further, when not in use, the operation of winding and binding the shaft when storing the balloon catheter can be easily performed. Further, since the metal reinforcing body has a configuration in which the polymer tube is covered, it is possible to improve the pressure resistance of the proximal shaft and thus to avoid the polymer tube from being extremely thick.

  The embodiment of the present invention has been described above. The above description is an illustration of a preferred embodiment of the present invention, and the scope of the present invention is not limited to this. That is, the description of the configuration of the above apparatus is an example, and it is obvious that various modifications and additions to these examples are possible within the scope of the present invention. For example, the dimensions of each part in the balloon catheter can be implemented with various changes.

1 is an external view showing a configuration of a balloon catheter according to an embodiment of the present invention. Sectional drawing of the principal part of the balloon catheter which concerns on one embodiment of this invention Sectional drawing of the proxy shaft which concerns on one embodiment of this invention The figure which uses for description of the pitch width of the slit in the metal reinforcement body which concerns on one embodiment of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Balloon catheter 20 Proximal shaft 23, 32 Polymer tube 24 Metal reinforcement 25 Covering surface 26 Spiral slit 30 Distal shaft 40 Balloon 80, 80a, 80b Insertion depth marker

Claims (1)

A proximal shaft with a first polymer tube extending from the proximal end to the distal end;
A distal shaft with a second polymer tube extending further distally from the distal end of the first polymer tube;
The proximal shaft is formed of a metal material so as to cover the entire inner peripheral surface of the first polymer tube from the proximal end to the distal end, and a covering portion that reinforces the rigidity of the proximal shaft; The covering portion is formed in a spiral shape with a pitch width that continuously decreases from the proximal end to the distal end over the entire length from the proximal end to the distal end. A balloon catheter comprising a metal reinforcing body having a slit portion to be adjusted.

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