JP5428209B2 - Medical balloon catheter - Google Patents

Description

  The present invention relates to percutaneous angioplasty (PTA: Percutaneus Transiential Angolaplasty or PTCA: Percutaneous Transluminal Coronary Angiography) for expanding and treating narrowed or occluded portions of vascular lumens such as coronary arteries, limb arteries, renal arteries and peripheral blood vessels. And the like, and the balloon catheter.

  The balloon catheter used for the treatment of PTA or PTCA has a balloon at the distal end of the shaft, and is mostly made of a flexible resin. To perform treatment in PTCA, a guiding catheter is first inserted from the femoral artery, the tip is positioned at the entrance of the coronary artery via the aorta, and then the guide wire passes through a stenosis or lesion site such as the coronary artery. Then, a balloon catheter is inserted along the guide wire so that the balloon matches the lesion site, and a contrast medium or the like is supplied to the balloon to expand the balloon. After dilation treatment of the lesion site, the balloon is decompressed and deflated, and the balloon catheter is removed from the body.

  In recent years, for balloon catheters, it is required to be applicable to lesion blood vessels with high stenosis and bend and extremely difficult, and to be able to smoothly advance the balloon to the lesion. It has been. For this reason, the balloon and its vicinity are softened, and the diameter is reduced by folding the balloon to reduce the diameter. Further, when the balloon once expanded is taken out of another lesioned part or outside the body, it is preferable that the balloon is deflated and the balloon is automatically folded around the catheter shaft to reduce the diameter. Various balloon shaping methods have been proposed for this purpose.

  For example, Patent Document 1 discloses a balloon having one or more surface portions in a balloon taper portion or a balloon having protrusions and / or grooves formed in the balloon taper portion. Patent Document 2 discloses a scroll shape in which a plurality of longitudinal grooves continuous at least in a part in the long axis direction and the same number of wings corresponding to the longitudinal grooves are formed in advance by a mold, and are formed by concave grooves and ridges. A method of shaping a balloon having wings and longitudinal grooves corresponding to a cross section is disclosed.

In the above patent document, various structures of the balloon are shown. However, when the protruding portion and / or groove portion of the tapered portion described in Patent Document 1 is expanded once, the balloon is plastically deformed. Lost and the shape of the catheter at the time of deflation is a plate containing the long axis of the catheter (winging state. In this plate state, the blade length perpendicular to the long axis is larger than the balloon diameter when the balloon is expanded, In addition to the large resistance at the time of removal, there is a risk of damaging normal blood vessels and the like. For this reason, it has been difficult to provide a balloon catheter having a desired re-passability (recross property) with a conventional balloon catheter. In addition, in the balloon having one or more surface portions in the balloon taper portion described in Patent Document 1, the end portion of the formed surface is sharp, and therefore when passing through a vascular stenosis site in a balloon expanded state or a contracted state There was a risk of damaging normal blood vessels. Moreover, although patent document 2 can implement | achieve a stable folding fold by forming a longitudinal groove and a wing | blade part, if it is made the shape which can achieve a stable folding fold, the balloon shape at the time of expansion will not become a substantially circular shape, and it is clinical. There was a problem that would be difficult to use.
JP 2002-263193 A JP2003-62080

  In view of the above problems, the present invention intends to solve the problem that, when the balloon is deflated, the balloon is stably folded around the catheter shaft and reduced in size to allow the balloon to pass through the vascular stenosis site. It is an object of the present invention to provide a balloon catheter that greatly reduces the resistance when it is taken out, and does not cause the risk of damaging normal blood vessels when passing through a vascular stenosis site in a balloon expanded state or a deflated state.

The medical balloon catheter of the present invention has a straight tube portion at the distal end of the catheter shaft, proximal and distal taper portions that are gradually reduced in diameter adjacent to both ends of the straight tube portion, and both ends of the taper portion. A medical balloon catheter configured by joining a balloon having a proximal side and a distal side sleeve portion adjacent to each other, wherein an inclination angle of the tapered portion with respect to a major axis direction is cycled in a circumferential direction. The boundary between the tapered portion and the straight tube portion is wave-shaped, and the phases of the proximal and distal tapered portions and the straight tube portion boundary are shifted from each other.

  The present invention also relates to a medical balloon catheter characterized in that the inclination angle of the tapered portion changes periodically and continuously over the entire circumferential direction.

  The present invention also relates to a medical balloon catheter in which an angle difference between the maximum value and the minimum value of the taper portion inclination angle is 2.5 ° or more.

  The present invention also relates to a medical balloon catheter having a waveform period of 120 ° or less.

  The present invention also relates to a medical balloon catheter characterized in that a recess is formed in at least a part of the tapered portion.

  According to the medical balloon catheter of the present invention, even after the balloon is expanded once, when it is deflated, it is folded small starting from a portion where the inclination angle of the tapered portion is large. When pushing into or pulling out, it becomes possible to reduce the pushing or taking out resistance. In addition, by shifting the phase of the boundary between the tapered part and the straight pipe part on the proximal side and the distal side, the balloon is folded into a small spiral when deflated. When pushing, the pushability at the time of passing can be improved.

  The medical balloon catheter of the present invention has a straight tube portion at the distal end of the catheter shaft, proximal and distal taper portions that are gradually reduced in diameter adjacent to both ends of the straight tube portion, and both ends of the taper portion. A medical balloon catheter configured by joining balloons having proximal and distal sleeve portions adjacent to each other, wherein the inclination angle of the tapered portion is periodically changed in the circumferential direction. The boundary between the tapered portion and the straight pipe portion is a wave shape.

  Hereinafter, various embodiments of a medical balloon catheter according to the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view showing the vicinity of the distal end portion of the first embodiment of the medical balloon catheter according to the invention.

  In this embodiment, the balloon catheter 1 has a balloon 10 joined to a catheter shaft 2 in which a guide wire passing tube 4 is disposed in the lumen of the outer tube 3. The balloon 10 has a tube shape, a straight tube portion 11 that expands or contracts by adjusting internal pressure, and proximal and distal taper portions 6A and 6B that are adjacent to both ends of the straight tube portion 11 and gradually reduce in diameter. And proximal and distal sleeve portions 7A and 7B which are adjacent to both ends of the tapered portions 6A and 6B and which are joined to the distal end of the outer tube 3 and the outer peripheral surface of the guide wire passing tube 4. It is composed.

  Further, an inflation lumen 8 through which a pressure fluid such as a physiological saline or a contrast medium introduced to apply an internal pressure to the balloon 10 is passed between the outer peripheral surface of the guide wire passing tube 4 and the inner peripheral surface of the outer tube 3. The above-described guide wire is inserted into the lumen (guide wire lumen) 9 of the guide wire passage tube 4. In addition, the most distal end 5 of the guide wire passing tube 4 is processed into a tapered shape whose outer diameter gradually decreases toward the tip so that the distal end 5 can smoothly advance in a narrow blood vessel or a highly narrowed portion. . In the catheter shaft (not shown), a manifold having a port communicating with the inflation lumen 8 and the guide wire lumen 9 is connected.

  As shown in FIG. 1, in the medical balloon catheter of the present invention, the inclination angle of the tapered portions 6A and 6B with respect to the major axis direction changes periodically and continuously over the entire circumferential direction of the balloon. As shown in FIG. 1, the taper portions 6A and 6B are formed such that the inclination angle thereof changes periodically and continuously over the entire circumferential direction of the balloon in the range of the maximum value α and the minimum value β. As a result, the resistance at the time of passing through the lesion site or the like is greatly reduced by folding the guide wire passing tube around the guide wire passing tube starting from the point where the inclination angle of the tapered portion becomes maximum when the balloon is deflated.

  In the present invention, various bonding forms can be adopted for bonding the balloon 10 and the catheter shaft 2, and the effect of the present invention is not limited at all. In the embodiment shown in FIG. 1, the outer peripheral surface of the distal end of the outer tube 3 is reduced in diameter in consideration of pressure resistance performance, and an example in which the proximal sleeve portion 7A is joined to the reduced diameter portion is shown. ing. According to such a joining form, the level | step difference which arises after both joining can be made small.

  In the medical balloon catheter of the present invention, the inclination angle of the taper portions 6A and 6B with respect to the major axis direction changes periodically and continuously over the entire circumferential direction of the balloon, so that the inclination angle of the taper portion is maximized when the balloon is deflated. As a starting point, the tube is folded small around the guide wire passage tube, and the resistance force when passing through a lesion site or the like is greatly reduced.

  In order to sufficiently reduce the resistance, the angle difference (α−β) between the maximum value and the minimum value of the inclination angle is preferably 2.5 ° or more, and is adjusted to 5 ° or more. Is particularly preferred. In addition, it is possible to form a recessed portion in the tapered portion after providing a difference in the inclination angle. In this case, the shape when the balloon is deflated can be further stabilized.

  Further, when the inclination angle of the tapered portions 6A and 6B with respect to the major axis direction changes periodically and continuously over the entire circumferential direction of the balloon, the boundary line between the tapered portions 6A and 6B and the straight tube portion 11 becomes A wave shape is formed, and the shape when the balloon 10 contracts is determined by the period of the waveform. In other words, when the period of the waveform is 120 ° (2 / 3π radians), as shown in FIG. 2, the taper shape in the cross section perpendicular to the balloon axial direction is a shape close to a triangle, and the shape when the balloon is deflated Is a triset. When the period of the waveform is 90 °, the taper shape in the cross section perpendicular to the balloon axial direction becomes a quadrangle shape, and the shape when the balloon is deflated is a tetraset. Thus, in order to stabilize the shape when the balloon is deflated, it is preferable that the period of the waveform is 120 ° or less.

  In the present invention, the balloon 10 is preferably produced by a blow molding method in order to have sufficient strength against the internal pressure introduced during expansion. Although general blow molding is employable, specifically, the following procedure can be exemplified. First, a tube-shaped parison having a predetermined inner diameter and outer diameter is produced by extrusion molding, and this parison is stretched to a length of 2 to 7 times at room temperature. Both the outer portions are pulled in the axial direction while locally heating the outer portions in the axial direction, that is, the portions that are later formed into the tapered portion and the sleeve portion. Thereby, the taper part and sleeve part after shaping | molding can fully be thinned.

  The parison thus preformed to have a predetermined length is transferred to a cavity in a blow molding die, the die is closed, and compressed air is blown into the inside to inflate the parison, and mold the cavity into the above balloon. The straight pipe portion 11, the tapered portions 6A and 6B and the sleeve portions 7A and 7B are formed. The cavity shape is preferably set to be slightly larger than the shape of the balloon that is a molded product. Moreover, in order to stabilize the shape dimension of a balloon, you may perform a heat setting process as needed. Examples of the resin material used for the parison include polyethylene terephthalate (PET), polyethylene, polyvinyl acetate, ionomer, polyvinyl chloride, polyamide (nylon 66, nylon 12, etc.), polyamide thermoplastic elastomer, polyester thermoplastic elastomer, and polyurethane. One type or a mixture of two or more types of thermoplastic elastomers can be used, and a multilayered parison combining these resin materials can be prepared. The present invention is not limited to the production conditions and materials of the balloon. For example, the production described in JP-A-3-37949, JP-A-3-57463, JP 3-37949, etc. Conditions and materials may be used.

  Further, after the above blow molding, the straight tube portion and the taper portion are fixed with a mold in order to more accurately reduce the thickness of the proximal and distal sleeve portions, and the proximal sleeve or the distal side is fixed. Only the sleeve may be pulled and stretched, or the sleeve portion may be subjected to grinding processing such as centerless grinding in order to make it thinner.

  Further, the outer tube 3 and the guide wire passing tube 4 constituting the catheter shaft 2 are formed by an extrusion method when made of a thermoplastic resin, and dip / cure forming method when made of a thermosetting resin such as polyimide. Can be produced. For the outer tube 3, nylon, polyamide elastomer, polyester elastomer, polyurethane elastomer, polyethylene, and the like that are relatively soft and have low flexural modulus and tensile strength can be suitably used. In particular, the guide wire passing tube 4 is made of high-density polyethylene or the like in order to ensure good slipperiness with respect to the guide wire, and a clearance of about 0.014 mm between the guide wire lumen and the inserted guide wire. Is preferably provided. Unlike the hard outer tube material, the proximal outer tube material connected to the manifold located at the proximal end is relatively soft and has a flexural modulus and tensile strength, unlike the hard outer tube material described above. It is preferable to use a high material.

  As described above, in the above-described embodiment, the configuration on the balloon distal side is mainly described. However, in the present invention, the same configuration can be adopted on the balloon proximal side. In this case, since the resistance force when the balloon catheter is retracted can be reduced, the risk of causing postoperative complications by damaging the intima of the blood vessel can be reduced. Further, it is possible to dispose the waveform phase at the boundary between the tapered portion and the straight tube portion on the distal side and the proximal side, and at this time, the profile when the balloon is deflated can be further reduced.

  In the above embodiment, a co-axial type catheter has been described. However, the present invention can also be applied to balloon catheters other than the co-axial type, for example, as described in JP-A-7-132147. Needless to say, it can be applied to a type having a plurality of axes. Furthermore, the present invention may be applied to various balloon catheters such as an over-the-wire type and a monorail type depending on the application.

  In addition, it is obvious to those skilled in the art that the present invention represented by the above embodiment is applicable not only to PTCA balloon catheters for treating coronary artery stenosis but also to peripheral blood vessels other than coronary arteries and applicable to dialysis shunts. It goes without saying that it can be applied to any lumen in the body that is difficult to pass through the balloon.

  Hereinafter, specific examples and comparative examples according to the present invention will be described in detail, but the following specific examples do not limit the present invention.

(Example 1)
A balloon catheter having the shape shown in FIG. 1 was produced as follows. That is, the catheter shaft 2 is a co-axial type having a double tube structure in which the guide wire passage tube 4 is disposed in the lumen of the outer tube 3. A polyethylene tube having an inner diameter of 0.43 mm, an outer diameter of 0.56 mm, and an overall length of 30 cm is used, and the outer tube 3 is a polyamide elastomer having an inner diameter of 0.72 mm, an outer diameter of 0.86 mm, and an overall length of 25 cm. A tube made of (trade name: PEBAX7233A01: manufactured by elf atom) was used. A normal catheter shaft has a total length of about 135 cm and is composed of a proximal segment having a total length of about 105 cm. However, in this embodiment, only the distal side needs to be evaluated. Does not adopt the segment structure.

  The balloon 10 joined to the distal end of the catheter shaft 2 was produced as follows. A tube-shaped parison (inner diameter: 0.45 mm, outer diameter: 0.87 mm) having a substantially circular inner and outer diameter was produced by extrusion molding using a polyamide elastomer (trade name: PEBAX7233A01: manufactured by elfatochem). Subsequently, a Φ3.00 mm balloon having a nominal pressure of 6 atmG and a rated breaking pressure of 16 atmG was produced by a biaxial stretch blow molding method using the parison.

  As shown in FIG. 3, the dimensions of each part of the balloon 10 are such that the maximum inclination angle α of the proximal and distal taper portions 6A or 6B is 15 °, the minimum inclination angle β is 12.5 °, and the difference (α -Β) is 2.5 °, the length of the straight tube portion 11 in the long axis direction is 14.5 mm, the wall thickness is 0.016 mm, the inner diameter of the distal sleeve portion 13B is 0.62 mm, and the outer diameter 0.72 mm, the length is 2 mm, the length of the proximal sleeve portion 13A is 5.0 mm, the inner diameter is 0.85 mm, and the outer diameter is 1.00 mm.

  Such a balloon 10 was joined to the catheter shaft 2 by heat welding, and the proximal end of the catheter shaft 2 was connected to a manifold to produce a balloon catheter (distal segment) of this example. Here, the proximal sleeve portion 7A is joined to a portion whose diameter is reduced across the outer diameter of the distal end of the outer tube 3 (longitudinal length 5 mm), and the distal sleeve portion 7B is The guide wire passing tube 4 was joined to the outer peripheral surface (the bonding margin was 2 mm in the long axis direction).

(Example 2)
Using a parison having the same size and shape as in Example 1, a balloon 20 as shown in FIG. 4 was produced using a balloon mold. Otherwise, the balloon catheter of Example 2 was produced in the same manner as in Example 1. As shown in FIG. 4, the dimensions of each part of the balloon 20 according to the second embodiment are such that the maximum and inclination angles α of the proximal and distal tapered portions 22A and 22B are 15 ° and the minimum inclination angle β is 12.5 °. The difference (α−β) is 2.5 °, and the waveforms of the proximal and distal tapered portions 22A, 22B and the straight tube portion boundary are parallel on the proximal side and the distal side. Be placed. Further, the length of the straight tube portion 21 in the major axis direction is 14.5 mm, the wall thickness is 0.016 mm, the length of the distal sleeve portion 23A is 2 mm, the inner diameter is 0.60 mm, and the outer diameter is 0. .71 mm, the length of the proximal sleeve 23B is 5 mm, its inner diameter is 0.85 mm, and its outer diameter is 0.95 mm.

(Comparative example)
A parison having the same size and shape as in Example 1 was used, and a balloon having a tapered portion and a straight tube portion having a substantially circular shape was produced using a balloon molding die. Other than that was carried out similarly to the said Example 1, and produced the balloon catheter of this comparative example. As shown in FIG. 5, the dimensions of each part of the balloon 30 according to this comparative example are as follows. The length of the straight tube portion 31 in the major axis direction is 14.5 mm, the thickness is 0.016 mm, and the distal sleeve portion 33A The length is 2 mm, the inner diameter is 0.60 mm, the outer diameter is 0.71 mm, the length of the proximal sleeve portion 33B is 5 mm, the inner diameter is 0.85 mm, and the outer diameter is 0.95 mm. The distal and proximal taper portions 32A and 32B were formed such that the inclination angle with respect to the major axis direction was constant over the circumferential direction (α = β = 15 °).

(Evaluation)
A simulated aorta and guiding catheter are placed in a water tank filled with physiological saline at 37 ° C., and a polyethylene simulated small diameter tube having an inner diameter of 1.50 mm simulating a stenotic lesion of the coronary artery is placed at the tip of the guiding catheter. The guide wire was inserted in the inside. Next, the balloon catheter was previously inserted into the guiding catheter along the guide wire, and the guide wire was arranged to protrude 100 mm from the distal end of the balloon catheter. The mixture of contrast medium and physiological saline was introduced into the balloon catheter up to 16 atm with an indeflator and held for 30 seconds, and then the balloon was deflated. The balloon catheter was pushed through a simulated small diameter tube using a slide table at 10 mm / sec, and the maximum load generated was measured with a digital force gauge at each level n = 5. As a result of the evaluation, Example 1 has a weight of 25 grams, Example 2 has a weight of 23 grams, and the comparative example has a weight of 35 grams. The embodiment has a lower load than the comparative example and passes through the vascular stenosis. It was confirmed that the resistance force was clearly reduced.

1 is a schematic sectional view showing a first embodiment of a balloon catheter according to the present invention. It is the shape of the taper part in 1st Example AA 'cross section. 3 is a schematic cross-sectional view showing dimensions of each part of a balloon according to Example 1. FIG. 6 is a schematic cross-sectional view showing dimensions of each part of a balloon according to Example 2. FIG. It is a schematic sectional drawing which shows each part dimension of the balloon which concerns on a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Balloon catheter 2 Catheter shaft 3 Outer tube 4 Guide wire passage tube 5 The most distal end of the guide wire passage tube 6A Proximal taper portion 6B Distal taper portion 7A Proximal sleeve portion 7B Distal sleeve portion 8 Inflation lumen 9 Guide wire lumen 10 Balloon 11 Balloon straight tube portion 20 Balloon 21 Balloon straight tube portion 22A Proximal taper portion 22B Distal taper portion 23A Proximal sleeve portion 23B Distal sleeve portion 30 Balloon 31 Balloon straight Tube portion 32A Proximal taper portion 32B Distal taper portion 33A Proximal sleeve portion 33B Distal sleeve portion

Claims (6)

At the distal end of the catheter shaft, a straight tube portion, proximal and distal taper portions that are gradually reduced in diameter adjacent to both ends of the straight tube portion, and proximal and distal portions that are adjacent to both ends of the taper portion A medical balloon catheter configured by joining a balloon having a side sleeve portion, wherein the proximal side and the distal side tapered portions are periodically inclined in the circumferential direction with respect to the major axis direction. The boundary between the taper portion and the straight tube portion becomes a wave shape, and the phases of the proximal and distal taper portions and the straight tube portion boundary are shifted from each other. Medical balloon catheter.   The medical balloon catheter according to claim 1, wherein the inclination angle of the taper portion changes periodically and continuously over the entire circumferential direction.   The medical balloon catheter according to claim 1 or 2, wherein an angle difference between a maximum value and a minimum value of the taper portion inclination angle is 2.5 ° or more.   The medical balloon catheter according to any one of claims 1 to 3, wherein a period of the waveform is 120 ° or less.   The medical balloon catheter according to any one of claims 1 to 4, wherein a concave portion is formed in at least a part of the tapered portion.   The medical balloon catheter according to any one of claims 1 to 5, wherein the boundary has a wave shape with a smooth curve over the entire circumferential direction.