JP5347656B2 - catheter - Google Patents

Description

  The present invention relates to a catheter, and more particularly to a catheter used for applications such as intra-aortic balloon pumping.

  In recent years, in the medical field, catheters are frequently used for various treatments and examinations. For example, an intra-aortic balloon pumping method (IABP method) is performed as a treatment for lowering cardiac function, in which a balloon catheter is inserted into the aorta, and the balloon is inflated and deflated according to the heart beat to assist the cardiac function. It has been broken.

  As an intra-aortic balloon catheter used in this IABP method, a catheter having a double tube structure formed by an outer tube and an inner tube located inside the outer tube is generally used.

  In such a double-tube catheter, blood is taken in from the distal end opening of the inner tube, and a blood pressure measurement device is attached to the proximal end opening to detect fluctuations in blood pressure. However, in recent years, the outer diameter of the catheter is reduced from the viewpoint of reducing the load on the patient, and therefore, the inner diameter of the inner tube constituting the blood pressure introduction hole is also reduced, making accurate blood pressure measurement difficult. If blood pressure measurement cannot be accurately performed with good timing, there is a possibility that treatment such as IABP cannot be performed well.

  Thus, recently, a catheter has been proposed in which a pressure sensor (electrical signal conversion method) is attached to the distal end of the catheter, and the blood pressure at the distal end of the catheter is detected as an electrical signal (for example, Patent Document 1). In such a conventional catheter, the pressure sensor is fixed to the distal end of the catheter with a hardened fluid substance such as an epoxy resin adhesive.

JP 10-137199 A

  However, when the mounting structure of the pressure sensor (electrical signal conversion method) is applied to mounting of a pressure sensor using light, there is a possibility that an error may occur in the measurement result of pressure measurement with time. However, it became clear by experiment of the present inventors.

  The present invention has been made in view of such a situation, and an object of the present invention is to be able to accurately measure blood pressure in a timely manner and to stably measure blood pressure without the measurement accuracy changing over time. Is to provide a simple catheter.

In order to achieve the above object, a catheter according to the present invention comprises:
A sensor capable of measuring pressure using light;
An optical fiber connected to the sensor and extending in the axial direction;
A gel-like substance filled around the sensor;
A peripheral wall defining a periphery of the gel material filling space;
The front end of the filling space is closed so as to partition the outside from which the pressure is to be measured and the filling space;
A highly rigid rear end partition wall closing the rear end of the filling space.

  An external pressure whose pressure is to be measured is measured by a sensor which is transmitted to the front end partition wall and the gel-like substance and fixed on the rear end partition wall. Since the sensor is a pressure sensor using light, even if the diameter of the catheter is reduced, it is possible to accurately measure blood pressure with good timing. Moreover, since the rigidity of the rear end partition wall for fixing the sensor is high, the blood pressure can be measured stably without the measurement accuracy changing over time.

Preferably, the peripheral wall is incorporated in the tip.
The distal tip has a guide wire insertion hole communicating with the outside whose pressure is to be measured,
A distal end of an inner tube is connected to the guide wire insertion hole of the tip;
A distal end of a balloon membrane capable of inflation and deflation is connected to the tip.

  Preferably, the distal end of the outer tube is connected to the proximal end of the balloon membrane. Preferably, the rear end partition wall is made of metal or ceramics. Preferably, the tip partition is made of a polyurethane film.

FIG. 1 is a schematic sectional view of a catheter according to an embodiment of the present invention. FIG. 2 is a perspective view of the tip chip shown in FIG. FIG. 3 is a cross-sectional view of the tip shown in FIG. 4 is a partial cross-sectional view of the proximal end of the balloon membrane shown in FIG. FIG. 5 is a partial enlarged cross-sectional view of the tip shown in FIG. FIG. 6 is a graph showing a change with time in pressure measurement according to an example and a comparative example of the present invention. FIG. 7 is a partial cross-sectional view of a distal tip of a catheter according to another embodiment of the present invention.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
First embodiment

  A balloon catheter 20 according to an embodiment of the present invention shown in FIG. 1 is a balloon catheter used for an intra-aortic balloon pumping method, and has a balloon portion 22 that expands and contracts in accordance with the pulsation of the heart. The balloon part 22 is comprised with the thin film about 50-150 micrometers in film thickness. The material of the thin film is not particularly limited, but is preferably a material excellent in bending fatigue resistance, and is made of, for example, polyurethane.

  The outer diameter and length of the balloon portion 22 are determined according to the inner volume of the balloon portion 22 that greatly influences the assisting effect on the cardiac function, the inner diameter of the arterial blood vessel, and the like. The inner volume of the balloon part 22 is not particularly limited, but is 20 to 50 cc. The outer diameter of the balloon part 22 is preferably 12 to 16 mm at the time of inflation, and the length is preferably 150 to 250 mm.

  The distal end portion 22a of the balloon portion 22 is attached to the outer periphery of the tip portion 25 by means such as heat fusion or adhesion. As shown in FIGS. 2 and 3, the tip tip portion 25 is formed with a wire insertion hole 23 communicating in the axial direction, and the distal end portion of the inner tube 30 enters the proximal end side thereof. The distal end of the inner tube 30 is fixed to the proximal end of the tip 25 so that the wire insertion hole communicates with the inside of the inner tube 30 by means such as heat fusion or adhesion.

  As shown in FIG. 3, a sensor accommodation hole 36 is formed inside the distal tip 25 separately from the wire insertion hole 23. A pressure sensor 40 (described later) is accommodated in the sensor accommodation hole 36. The distal end partition film 39 having flexibility is joined to the distal end opening of the sensor accommodation hole 36 by heat welding or adhesion, and the inside is closed in a sealed state. The tip partition wall film 39 is made of, for example, a polyurethane film having a film thickness of about 2 to 20 μm, a silicone film, a polyamide elastomer film, a polyester elastomer film, a polyethylene film, or a polypropylene film.

  As shown in FIG. 2, at the distal end of the tip chip 25, a flat surface 25a to which a tip partition wall film 39 is bonded, and an inclined surface 25b inclined with a predetermined inclination angle with respect to the flat surface 25a. And formed. A wire insertion hole 23 is opened in the inclined surface 25b. By opening the wire insertion hole 23 in the inclined surface 25b, the opening area can be increased, and the operator who handles the balloon catheter 20 can easily pass the guide wire.

  As shown in FIG. 1, the proximal end portion 22 b of the balloon portion 22 is connected to the outer periphery of the distal end portion of the outer tube 24. The pressure fluid is introduced and led out into the balloon portion 22 through the pressure fluid passage 29 formed in the outer tube 24, and the balloon portion 22 is inflated and deflated. The connection between the balloon portion 22 and the outer tube 24 is performed by heat fusion or bonding with an adhesive.

  The inner tube 30 extends in the axial direction inside the balloon portion 22 and the outer tube 24, and does not communicate with the pressure fluid communication path 29 formed inside the balloon portion 22 and inside the outer tube 24. A wire passage 31 is formed and communicates with a second port 32 of a branching portion 26 described later.

  When the balloon catheter 20 is inserted into the artery, the inner tube 30 positioned in the balloon portion 22 is wound around the balloon portion 22 in a deflated state, and the wire passage 31 conveniently brings the balloon portion 22 into the artery. It is used as a lumen through which a guide wire used for insertion is inserted.

  A branch portion 26 is connected to the proximal end portion of the outer tube 24. The branch portion 26 is formed separately from the outer tube 24 and is connected to the outer tube 24 by means such as heat fusion or adhesion. In the branch portion 26, a first passage 45 in which a first fluid port 29 for introducing and deriving a pressure fluid into and out of the pressure fluid passage 29 and the balloon portion 22 in the outer tube 24 is formed, and in the inner tube 30. A second passage 47 in which a second port 32 communicating with the wire passage 31 is formed is formed.

  The first port 28 is connected to a pump device (not shown), and pressure fluid is introduced into and led out from the balloon portion 22 by this pump device. Although it does not specifically limit as a pressure fluid, Helium gas with small viscosity and mass etc. are used so that the balloon part 22 expand | swells and shrinks rapidly according to the drive of a pump apparatus.

  In addition to the first port 28 and the second port 32, a third port 49 is formed in the branch portion 26. The optical fiber 33 is pulled out from the third port 49. The outlet of the optical fiber 33 in the third port 49 is configured so that the fluid inside the first passage 45 and the second passage 47 does not leak to the outside.

  An optical connector 42 is connected to the proximal end of the optical fiber 33. A pressure sensor 40 shown in FIG. 3 is connected to the distal end of the optical fiber 33. A blood pressure measuring device (not shown) is connected to the optical connector 42. Based on the blood pressure fluctuation measured by this blood pressure measuring device, the pump device is controlled in accordance with the heart beat, and the balloon portion 22 is inflated and deflated in a short cycle of 0.4 to 1 second.

  In the present embodiment, it is preferable that the outer tube 24 and the inner tube 30 are fixed by an adhesive. By fixing the outer tube 24 and the inner tube 30 in this manner, the flow resistance of the pressure fluid conduction path 29 in the outer tube 24 is lowered, and the responsiveness of the balloon portion 22 is improved. The adhesive used for fixing is not particularly limited, and adhesives such as cyanoacrylate adhesives and epoxy adhesives can be used, and it is particularly preferable to use cyanoacrylate adhesives.

  Further, in the present embodiment, as shown in FIG. 4, the distal end portion of the outer tube 24 extends in the circumferential direction of the outer tube 24 at a position away from the distal end opening surface 50 toward the proximal end by a predetermined width. A notch 52 is formed. The cutting angle of the cutting 52 is not particularly limited, but it is preferable that the cutting angle is substantially the same as the inclination angle of the tip opening surface 50. Moreover, it is preferable that the notch 52 is formed in the position away from the most advanced corner | angular part in the front end opening surface 50 in the axial direction by the predetermined width.

  The depth D1 of the notch 52 in the direction perpendicular to the longitudinal axis of the outer tube 24 is preferably not more than the outer diameter D2 of the inner tube 30, and is particularly 55 to 90% of the outer diameter D2. preferable. If the depth D1 is too small, it is difficult to form the engagement hole 56 for inserting the inner tube 30, and if it is too large, the outer tube 24 and the inner tube 30 may not be firmly fixed. There is.

  The predetermined width of the cut is not particularly limited, but is preferably 1 to 3 mm. If the width is too small, the inner tube 30 may be insufficiently fixed. If the width is too large, the width of the cut piece 54 formed by the cut 52 is increased, and the cut piece 54 is formed at the tip opening surface. There is a possibility that the responsiveness of the balloon portion 22 is deteriorated by entering the entrance / exit of the pressure fluid communication path 29 at 50.

  A notch piece 54, which is a part of the tube wall of the outer tube 24 located between the notch 52 and the tip opening surface 50, is pushed toward the inside of the outer tube 24, thereby inserting the inner tube 30. Possible engagement holes 56 are formed. The inner tube 30 is fixed to the outer tube 24 by inserting the inner tube 30 through the engagement hole 56.

  In the balloon catheter 20 of the present embodiment, the outer diameter of the inner tube 30 is not particularly limited, but is preferably 0.5 to 1.5 mm, and preferably 30 to 60% of the inner diameter of the outer tube 24. In this embodiment, the outer diameter of the inner tube 30 is substantially the same along the axial direction. The inner tube 30 is made of, for example, a synthetic resin tube such as polyurethane, polyvinyl chloride, polyethylene, nylon, polyether ether ketone (PEEK), a nickel titanium alloy thin tube, a stainless steel thin tube, or the like. Further, when the inner tube 30 is composed of a synthetic resin tube, a stainless steel wire or the like may be embedded.

  The outer tube 24 is not particularly limited, but is composed of a synthetic resin such as polyurethane, polyvinyl chloride, polyethylene terephthalate, or polyamide, and may be embedded with a stainless steel wire or the like. The inner diameter D0 and the wall thickness of the outer tube 24 are not particularly limited, but the inner diameter D0 is preferably 1.5 to 4.0 mm, and the wall thickness is preferably 0.05 to 0.4 mm. The length of the outer tube 24 is preferably 300 to 800 mm.

  As shown in FIG. 5, in the present embodiment, a short tube 37 is embedded in the distal end portion of the sensor accommodation hole 36 of the tip chip 25. A plug member 35 is fixed inside the proximal end of the short tube 37 by means such as adhesion or fusion. A through hole 35 a is formed in the central portion of the plug member 35, and the optical fiber 33 is drawn out to the proximal end side of the sensor accommodation hole 36 through the through hole 35 a.

  As shown in FIG. 3, the optical fiber 33 drawn to the proximal end side of the sensor accommodation hole 36 is drawn to the inside of the balloon portion 22 through the through hole 27 formed in the distal tip 25. Inside the balloon portion, the optical fiber 33 is fixed to the outer peripheral portion of the inner tube 30 by a heat shrinkable tube 34.

A pressure sensor 40 is connected to the distal end of the optical fiber 33, and a part of the distal side of the optical fiber 33 is fixed to the plug member 35 by means such as heat fusion, adhesion, or caulking. is there. The space surrounded by the plug member 35, the short tube 37, and the tip partition wall film 39 forms a gel-like substance filling space 38, the plug member 35 forms a highly rigid rear end partition wall, and the short tube 37 is surrounded by It constitutes a wall.
As the pressure sensor 40, those described in JP-T-2008-524606, JP-A-2000-35369, and the like can be used.

  The short tube 37 is configured to be equal to or shorter than the axial length of the sensor housing hole 36 formed in the tip 25, and the film thickness thereof is preferably 30 to 150 μm. For example, polyurethane, polyamide Polyester, silicone, stainless steel, nickel titanium, glass, ceramics, etc.

  The plug member 35 is made of a highly rigid material such as metal or ceramics. Examples of the highly rigid material include stainless steel, iron, aluminum, nickel titanium, and glass. Examples of stainless steel include SUS304, SUS316, and SUS440.

  Examples of the gel substance filled in the filling space 38 include silicone gel, polyacrylamide gel, and polyethylene oxide gel. A part of the distal side of the optical fiber 33 is fixed to the plug member 35 so that the gel-like substance filled in the filling space 38 does not enter the through hole 35a formed in the plug member 35. is there.

  The pressure sensor 40 is a sensor that detects the pressure in the filling space 38 using a path difference of light transmitted through the optical fiber 33. The blood pressure of the blood located outside the distal tip 25 is transmitted to the gel substance in the filling space 37 via the distal partition membrane 39.

The pressure sensor 40 is attached to the inside of the sensor accommodation hole 36 formed in the tip 25 shown in FIGS. 3 and 5 as follows. First, the plug member 35 is inserted into the proximal end opening of the short tube 37 and fixed. Next, the optical fiber with the pressure sensor 40 is passed through a through hole 35a formed in the plug member 35, and the optical fiber in the through hole 35a portion is fixed by means such as adhesion, and the pressure sensor 40 is fixed to the plug member 35. Secure to.
The pressure sensor 40 is preferably surrounded by a gel material. In such a state, there is an advantage that it is hardly affected by deformation of the surrounding wall.

  Next, the short tube 37 with the plug member 35 to which the pressure sensor 40 is fixed is inserted into the distal end of the sensor receiving hole 36 and fixed. Then, the filling space 38 is sealed by filling the inside of the filling space 38 with a gel substance and fixing the tip partition wall membrane 39 to the distal end face of the tip tip 25. In addition, without the short tube 37, the plug member 35 is fixed to the inner wall of the sensor receiving hole 36 to form the filling space 38, and the tip partition wall membrane 39 is fixed to the distal end face of the tip tip 25, thereby filling the filling space 38. May be sealed.

  In the balloon catheter 20 of the present embodiment, the blood pressure of the blood located outside the distal tip 25 where the pressure is to be measured is transmitted to the gel substance in the filling space 38 via the distal partition wall film 39 and is blocked by the plug member 35. It is measured by a fixed pressure sensor 40. Since the pressure sensor 40 is a pressure sensor using light, even if the outer tube 24 is made thinner, it is possible to accurately measure the blood pressure with good timing.

  In addition, since the plug member 35 as a rear end partition wall for fixing the pressure sensor 40 has high rigidity, it is possible to stably measure blood pressure without the measurement accuracy changing over time. For example, when stainless steel is used as the plug member 35, the difference between the pressure measured using the pressure sensor 40 and the actual pressure actually measured using the pressure transducer, as shown by the curve A shown in FIG. It was confirmed that the measurement accuracy did not change with time.

A curve B shown in FIG. 6 is a comparative example in which the plug member 35 is made of a two-component curable adhesive. In this case, it was confirmed that the measurement accuracy changes with time.
Second embodiment

  In this embodiment, as shown in FIG. 7, a stopper member 35 is fixed inside the distal end of the catheter tube 124 that does not have a balloon portion, and a gel material filling space 138 is provided on the distal end side. The catheter 120 is configured in the same manner as in the first embodiment except that the filling space 138 is sealed with the distal partition membrane 139. In this embodiment, the peripheral wall that defines the periphery of the gel-like substance filling space 138 is constituted by the distal end portion of the catheter tube 124 itself.

The catheter tube 124 of this embodiment corresponds to the tube 37 that forms the peripheral wall of the first embodiment, and the filling space 138 corresponds to the filling space 38, and the tip partition membrane 139 corresponds to the tip partition membrane 39. Correspondingly, detailed description thereof is omitted. Further, the other constituent members shown in FIG. 7 are denoted by the same reference numerals as those in the first embodiment, and the description thereof is omitted. Also in this embodiment, the same operational effects as in the first embodiment can be obtained.
Other embodiments

  The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention. For example, the catheter of the present invention can be used as a PTCA catheter, a PTA catheter, or other catheters in addition to an IABP catheter.

20, 120 ... Balloon catheter 22 ... Balloon part 24 ... Outer tube 124 ... Catheter tube 25 ... Tip tip 30 ... Inner tube 31 ... Wire passage 33 ... Optical fiber 35 ... Plug member 36 ... Sensor housing hole 37 ... Short tube 38, 138 ... Filling space 39, 139 ... End partition wall film 40 ... Pressure sensor

Claims (5)

A sensor capable of measuring pressure using light;
An optical fiber connected to the sensor and extending in the axial direction;
A gel-like substance filled around the sensor;
A peripheral wall defining a periphery of the gel material filling space;
The front end of the filling space is closed so as to partition the outside from which the pressure is to be measured and the filling space;
A plug member closing the rear end of the filling space ,
The plug member is made of a highly rigid metal or ceramic,
A part of the optical fiber is fixed to the plug member,
A catheter for measuring blood pressure by the sensor and the optical fiber . The peripheral wall is incorporated in the tip,
The distal tip has a guide wire insertion hole communicating with the outside whose pressure is to be measured,
A distal end of an inner tube is connected to the guide wire insertion hole of the tip;
The catheter according to claim 1, wherein a distal end of a balloon membrane capable of inflation and deflation is connected to the tip.   The catheter according to claim 2, wherein a distal end of an outer tube is connected to a proximal end of the balloon membrane. The catheter according to claim 1 wherein the plug member, characterized in Rukoto is composed of stainless steel. The tip partition is any one of a polyurethane film, a silicone film, a polyamide elastomer film, a polyester elastomer film, a polyethylene film, and a polypropylene film having a thickness of 2 to 20 μm . The catheter according to 1.

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