U.S. patent application number 16/848967 was filed with the patent office on 2020-07-30 for balloon catheter.
This patent application is currently assigned to ASAHI INTECC CO., LTD.. The applicant listed for this patent is ASAHI INTECC CO., LTD.. Invention is credited to Takeharu KATSURADA, Takeshi MOGI.
Application Number | 20200238057 16/848967 |
Document ID | 20200238057 / US20200238057 |
Family ID | 1000004754365 |
Filed Date | 2020-07-30 |
Patent Application | download [pdf] |
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United States Patent
Application |
20200238057 |
Kind Code |
A1 |
KATSURADA; Takeharu ; et
al. |
July 30, 2020 |
BALLOON CATHETER
Abstract
A balloon catheter comprises a balloon, an outer tube connected
to a proximal end of the balloon, an inner tube disposed inside the
outer tube and having a distal end attached to a distal end of the
balloon, a protruded-depressed portion formed on an outer periphery
of the inner tube, and a core wire disposed between the outer tube
and the inner tube. The core wire has a bulged portion sandwiched
between the outer tube and a depressed portion of the
protruded-depressed portion. The balloon catheter can transmit a
force from the core wire to both the outer tube and the inner tube
regardless of whether the force is generated by pushing or pulling
a proximal end portion of the balloon catheter. Additionally, the
core wire can move appropriately to maintain the flexibility of the
balloon catheter even when the balloon catheter bends.
Inventors: |
KATSURADA; Takeharu;
(Nagoya-shi, JP) ; MOGI; Takeshi; (Owariasahi-shi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ASAHI INTECC CO., LTD. |
Seto-shi |
|
JP |
|
|
Assignee: |
ASAHI INTECC CO., LTD.
Seto-shi
JP
|
Family ID: |
1000004754365 |
Appl. No.: |
16/848967 |
Filed: |
April 15, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15876432 |
Jan 22, 2018 |
10653869 |
|
|
16848967 |
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|
14944449 |
Nov 18, 2015 |
9913966 |
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15876432 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 25/1006 20130101;
A61M 25/1002 20130101; A61M 2025/0063 20130101; A61M 25/0147
20130101; A61M 25/104 20130101; A61M 2025/015 20130101; A61B 17/22
20130101; A61B 2017/22062 20130101 |
International
Class: |
A61M 25/10 20060101
A61M025/10; A61B 17/22 20060101 A61B017/22; A61M 25/01 20060101
A61M025/01 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 10, 2015 |
JP |
2015-047146 |
Claims
1. A catheter comprising: an outer tube; an inner tube disposed
inside the outer tube; a protruded-depressed portion provided on an
outer periphery of the inner tube, the protruded-depressed portion
including a plurality of protruded portions and a plurality of
depressed portions alternately arranged along a longitudinal
direction of the inner tube; and a core wire disposed between the
outer tube and the inner tube, and having a bulged portion, wherein
a periphery of the bulged portion is disposed between a first
protruded portion and a second protruded portion, which are two of
the plurality of protruded potions that are located adjacent each
other.
2. The catheter according to claim 1, wherein the bulged portion is
provided at a distal end of the core wire.
3. The catheter according to claim 1, wherein the bulged portion is
freely movable relative to the outer tube and the first and second
protruded portions.
4. The catheter according to claim 1, wherein: the bulged portion
is connected to a distal end of a distal end portion of the core
wire; and a diameter of the bulged portion is larger than a wire
diameter of the distal end portion of the core wire.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of application Ser. No.
15/876,432 filed Jan. 22, 2018, which in turn is a continuation of
application Ser. No. 14/944,449 filed Nov. 18, 2015, which claims
priority to Japanese Application No. 2015-047146 filed Mar. 10,
2015. The disclosure of the prior applications is hereby
incorporated by reference herein in its entirety.
BACKGROUND
[0002] The disclosed embodiments relate to a medical device.
Specifically, the disclosed embodiments relate to a balloon
catheter.
[0003] Balloon catheters, which are used for expanding a stenosis
site and the like in a lumen such as a blood vessel, are
traditionally known.
[0004] A balloon catheter mainly comprises a balloon as an
expanding object, an outer tube attached to a proximal end portion
of the balloon, and an inner tube disposed inside an inner cavity
of the outer tube and having a distal end portion attached to a
distal end portion of the balloon.
[0005] The outer tube is designed for allowing an expansion liquid
such as physiological saline to flow through a cavity defined
between the outer tube and the inner tube in order to expand the
balloon. The inner tube is designed so that a guide wire may be
inserted into the inner tube in order to guide the balloon catheter
to an affected area.
[0006] In general, a balloon catheter is used as follows: an
operator such as a physician holds the balloon catheter at a
proximal end portion of the balloon catheter and pushes a distal
end portion of the balloon catheter into a blood vessel. Therefore,
in order to position the balloon in a desired location of an
affected area, excellent pushability into the affected area and
excellent maneuverability of the distal portion are required.
[0007] Japanese Patent Application Laid-Open No. 2012-20077
describes a balloon catheter comprising a core wire inserted
between a catheter shaft (an outer tube) and an inner shaft (an
inner tube) in addition to the configuration described above,
wherein the core wire is sandwiched between the outer tube and the
inner tube.
[0008] According to Japanese Patent Application Laid-Open No.
2012-20077, the balloon catheter can supposedly improve the
pushability of the balloon catheter without the need for a
complicated process by simply sandwiching the core wire between the
outer tube and the inner tube.
[0009] However, the balloon catheter described in Japanese Patent
Application Laid-Open No. 2012-20077 has the following problems.
Although the pushability of the catheter may be improved, in a case
where the proximal end portion of the balloon catheter is pulled,
the resulting pulling force cannot be transmitted to the balloon
catheter through the core wire. Further, in a case where a pushing
force against the proximal end portion of the balloon catheter is
very strong, the core wire will move between the outer tube and the
inner tube in the distal direction. Therefore, the core wire will
be fixed between the outer tube and the inner tube, interfering
with the flexibility of the balloon catheter.
SUMMARY
[0010] The disclosed embodiments address the above problems. An
objective of the disclosed embodiments is to provide a balloon
catheter in which a function for transmitting a force from a core
wire to both an outer tube and an inner tube can be maintained
regardless of whether the force is generated by pushing or pulling
the proximal end portion of the balloon catheter, and in which the
core wire is allowed to move appropriately to maintain the
flexibility of the balloon catheter even when the balloon catheter
bends.
[0011] In order to address the aforementioned problems, the
disclosed embodiments include a balloon catheter comprising a
balloon, an outer tube connected to a proximal end of the balloon,
an inner tube disposed inside the outer tube and having a distal
end connected to a distal end of the balloon, a protruded-depressed
portion (i.e., a convex-concave textured portion) formed on an
outer periphery of the inner tube, and a core wire disposed between
the outer tube and the inner tube. The core wire has a bulged
portion (i.e., an enlarged portion) sandwiched between the outer
tube and a depressed portion of the protruded-depressed portion.
Therefore, a force can be transmitted from the core wire to both
the outer tube and the inner tube regardless of whether the force
is generated by pushing or pulling the proximal end portion of the
balloon catheter. Additionally, the bulged portion of the core wire
can move appropriately between depressed portions of the
protruded-depressed portion to maintain the flexibility of the
balloon catheter even when the balloon catheter bends.
[0012] The protruded-depressed portion may be formed by winding a
wire around the outer periphery of the inner tube to form a coil
body having a large pitch (that is, a coil body in which adjacent
windings of the wire are spaced apart from each other when the
balloon catheter is in an unbent state). Therefore, this simple
configuration can allow the force of pushing and/or pulling to be
transmitted from the core wire to both the outer tube and the inner
tube, and a kink in the inner tube can be prevented in addition to
the advantageous effects described above.
[0013] A surface of the coil body may be coated with a resin so
that the outer periphery of the inner tube forms streamlined
(smoothed) protrusions and depressions along the shape of the wire
of the coil body. Therefore, the bulged portion can move more
smoothly in addition to the advantageous effects described
above.
[0014] The balloon catheter of the disclosed embodiments may
satisfy the relationship Dc>Da>Db, wherein Da represents a
distance between an inner wall of the outer tube and a base of each
of the depressed portions of the protruded-depressed portion in a
radial direction of the balloon catheter, Db represents a distance
between the inner wall of the outer tube and an apex of each of the
protruded portions of the protruded-depressed portion in the radial
direction of the balloon catheter, and Dc represents an outer
diameter of the bulged portion. Therefore, when the proximal end
portion of the balloon catheter is pushed and/or pulled, the
resulting force can be better transmitted from the core wire to
both the outer tube and the inner tube in addition to the
advantageous effects described above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 shows a schematic overall view of a balloon catheter
according to the disclosed embodiments.
[0016] FIG. 2 shows a partial enlarged view of region A of FIG.
1.
[0017] FIG. 3 shows a schematic overall view of a balloon catheter
according to the disclosed embodiments.
[0018] FIG. 4 shows a partial enlarged view of region B of FIG.
3.
[0019] FIG. 5 shows a schematic overall view of a balloon catheter
according to the disclosed embodiments.
[0020] FIG. 6 shows a partial enlarged view of region C of FIG.
5.
[0021] FIG. 7 shows an enlarged view of a main section of a balloon
catheter according to the disclosed embodiments.
[0022] FIG. 8 shows a diagram illustrating movement of a bulged
portion of a core wire of the balloon catheter of FIG. 7.
DETAILED DESCRIPTION OF EMBODIMENTS
[0023] The configuration of a balloon catheter according to the
disclosed embodiments will be described below with reference to the
Figures. In each of FIGS. 1 to 8, the left side corresponds to a
distal side (a front side) that is to be inserted into the body,
and the right side corresponds to a proximal side (a base side)
that is to be operated by an operator such as a physician. For
parts in common with each configuration, description will be
omitted and the same reference numbers will be assigned in the
figures.
[0024] FIG. 1 shows a schematic overall view of a balloon catheter
according to the disclosed embodiments, and FIG. 2 shows a partial
enlarged view of region A of FIG. 1.
[0025] A balloon catheter 10 shown in FIG. 1 comprises a balloon
30, an outer tube 20 connected to a proximal end portion of the
balloon 30, an inner tube 40 inserted inside the outer tube 20 and
having a distal end connected to a distal end of the balloon 30, a
hypotube 23 connected to a proximal end of the outer tube 20, a
core wire 60 inserted between the outer tube 20 and the inner tube
40 and having a proximal end connected to a distal end portion of
the hypotube 23, and a connector 70 connected to a proximal end
portion of the hypotube 23.
[0026] The balloon 30 comprises an expanding part 31 that expands
due to the pressure of a liquid injected inside, a distal
attachment part 32 connected to the distal end of a distal end
portion 40a of the inner tube 40, and a proximal attachment part 33
connected to an outer periphery of a distal end of the outer tube
20. The expanding part 31 can be expanded with the pressure of the
liquid injected inside to form an inner cavity 34 and to have a
bag-like shape. Further, the inner cavity 34 of the balloon 30
communicates with an inner lumen 28 of the outer tube 20.
[0027] The outer tube 20 is a tubular body having a distal end
outer tube 21 located on a distal side of the outer tube 20 and a
proximal end outer tube 22 located on a proximal side of the outer
tube 20. The inner lumen 28 extends continuously from the distal
end outer tube 21 to the proximal end outer tube 22. Further, a
liquid for expanding the balloon 30 can flow through the inner
lumen 28 of the outer tube 20.
[0028] The distal end outer tube 21 and the proximal end outer tube
22 may be formed from a resin such as polyamide, polyamide
elastomer, polyolefin, polyester, or polyester elastomer, for
example.
[0029] The distal end outer tube 21 comprises a body tube 21a
located on a distal side of the distal end outer tube 21, and a
port tube 21b located on a proximal side of the distal end outer
tube 21. The proximal attachment part 33 of the balloon 30 is
connected to an outer periphery of a distal end of the body tube
21a.
[0030] The port tube 21b has an inner cavity in communication with
the inner lumen 28 and an opening (a proximal end opening) 44 in
which a proximal end portion 40b of the inner tube 40 described
below is open to the environment. Note that the port tube 21b may
be formed from a resin harder than that of the body tube 21a.
[0031] The inner tube 40 is a tubular body having a distal end
portion 40a and the proximal end portion 40b and is inserted
coaxially with the outer tube 20 into the inner lumen 28 of the
distal end outer tube 21 of the outer tube 20. The inner tube 40
has an inner lumen 41 in which a guide wire not shown in the figure
may be inserted.
[0032] Further, a protruded-depressed portion 45 comprising
protruded portions 45a and depressed portions 45b, which are of
spiral or annular shapes in a longitudinal direction of the balloon
catheter 10, is formed on an outer periphery of the inner tube 40
throughout the entire length of the inner tube 40. Note that the
inner tube 40 may be formed of the same resin as the distal end
outer tube 21 and the proximal end outer tube 22.
[0033] The distal end portion 40a of the inner tube 40 protrudes
from a distal end of the distal end outer tube 21, and a tip 42
formed of a soft resin may be attached to a distal end of the
distal end portion 40a.
[0034] The hypotube 23 is a metal tubular body. The proximal end
outer tube 22 is connected to an outer periphery of the distal end
portion of the hypotube 23, and the connector 70 is attached to the
proximal end portion of the hypotube 23. Further, a proximal end
portion 60b of the core wire 60 described below is connected to an
inside of the distal end portion of the hypotube 23.
[0035] As a material of the hypotube 23, for example, a
superelastic alloy such as stainless steel or a Ni--Ti alloy may be
used.
[0036] The core wire 60 comprises a distal end portion 60a, the
proximal end portion 60b, and a bulged portion 80 connected to a
distal end of the distal end portion 60a and having a diameter
larger than a wire diameter of the distal end portion 60a.
[0037] The proximal end portion 60b of the core wire 60 is
connected to the inside of the distal end portion of the hypotube
23 by joining means such as welding, adhesives, and the like, and
the bulged portion 80 disposed at the distal end portion 60a of the
core wire 60 is sandwiched between the outer tube 20 and one of the
depressed portions 45b of the protruded-depressed portion 45.
[0038] The connector 70 is a resin tubular member. When a liquid is
supplied from an indeflator (not shown) attached to a proximal end
of the connector 70, the liquid enters the inner cavity 34 of the
balloon 30 from the hypotube 23 through the inner lumen 28 to
expand the balloon 30.
[0039] The tip 42 is a tapered tubular member having an outer
diameter that gradually decreases in the distal direction, and
having a distal end opening 43 at a distal end of the tip 42. The
tip 42 may be formed of a resin softer than that of the distal end
portion 40a of the inner tube 40.
[0040] Further, two radiopaque markers 35a and 35b separated by a
predetermined distance are attached to the distal end portion 40a
of the inner tube 40 inside of the expanding part 31 of the balloon
30.
[0041] A case where the balloon catheter 10 is used in a procedure
for expanding a stenosis site in the coronary artery of the heart
will be described based on the above configuration.
[0042] A guide wire is inserted into the coronary artery of the
heart having a stenosis site as a treatment target before operation
of the balloon catheter 10 begins. First, an operator inserts a
proximal end of this guide wire through the distal end opening 43
of the balloon catheter 10 and passes it through the inner lumen 41
of the inner tube 40, and then retrieves the guide wire through the
proximal end opening 44. Subsequently, while holding the guide
wire, a proximal end portion of the balloon catheter 10 is pushed
in the distal direction to advance the balloon catheter 10 into the
patient's blood vessel.
[0043] The pushing force with which an operator pushes is first
transmitted to the outer tube 20 and the core wire 60 from the
hypotube 23. In this case, the bulged portion 80 disposed at the
distal end portion 60a of the core wire 60 is sandwiched between
the outer tube 20 and one of the depressed portions 45b of the
protruded-depressed portion 45, and thus the pushing force
transmitted to the outer tube 20 and the core wire 60 is also
transmitted to the inner tube 40.
[0044] Further, since the bulged portion 80 is sandwiched, but not
fixed, between the outer tube 20 and one of the depressed portions
45b of the protruded-depressed portion 45, the bulged portion 80 is
capable of moving in both the distal and proximal directions as
needed. For example, the bulged portion 80 can move to a distally
adjacent one of the depressed portions 45b in a case where the
balloon catheter 10 bends toward the side of the core wire 60 due
to the serpentine state of a patient's blood vessel. On the other
hand, in a case where the balloon catheter 10 bends toward the
opposite side of the core wire 60, the bulged portion 80 can move
to a proximally adjacent one of the depressed portions 45b.
Therefore, the flexibility of the balloon catheter 10 can be
maintained.
[0045] If the bulged portion 80 was both sandwiched and fixed (that
is, adhered) between the outer tube 20 and one of the depressed
portions 45b of the protruded-depressed portion 45, the balloon
catheter 10 would be difficult to bend due to the rigidity of the
core wire 60 and the like in a case where the balloon catheter 10
bends toward the side of the core wire 60 or the opposite side of
the core wire 60 depending on the serpentine state of a patient's
blood vessel. In contrast, the balloon catheter 10 in which the
bulged portion 80 is not fixed in place will bend flexibly
depending on the serpentine state of a patient's blood vessel since
the rigidity of the core wire 60 will not interfere with the
maneuverability of the balloon catheter 10 through a curved
vessel.
[0046] Further, the bulged portion 80 moves to the distally
adjacent one of the depressed portions 45b when the pushing force
to the core wire 60 exceeds a predetermined value, and thus an
excessive force will not be transmitted to a distal end of the
balloon catheter 10. An operator can therefore safely operate the
balloon catheter 10.
[0047] Subsequently, an operator positions the balloon 30 at a
stenosis site as a target site while observing markers 35a and 35b
under radioscopy, and then supplies a liquid from an indeflator
(not shown) connected to the connector 70. At this time, the liquid
flows into the inner lumen 28 of the outer tube 20, and flows out
from the distal end of the distal end outer tube 21 into the inner
cavity 34 of the balloon 30 to expand the balloon 30, which in turn
expands the stenosis site at the same time.
[0048] After expanding the stenosis site with the balloon 30, the
operator discharges the liquid from the balloon 30 with the
indeflator. That is, the liquid flows out of the inside of the
balloon 30 and is discharged through the inner lumen 28 of the
outer tube 20. Then, the balloon catheter 10 is pulled out of the
patient's body to complete the procedure.
[0049] A pulling force is also first transmitted to the outer tube
20 and the core wire 60 from the hypotube 23 when the operator
pulls the balloon catheter 10 out of the patient's body. In this
case, the bulged portion 80 disposed at the distal end portion 60a
of the core wire 60 is sandwiched between the outer tube 20 and one
of the depressed portions 45b of the protruded-depressed portion
45, and thus the pulling force transmitted to the outer tube 20 and
the core wire 60 is also transmitted to the inner tube 40, enabling
smooth withdrawal of the balloon catheter 10 from the patient's
body.
[0050] In the case of the balloon catheter 10, the following
operational effects can be achieved.
[0051] (1) The balloon catheter 10 comprises the balloon 30, the
outer tube 20 connected to the proximal end of the balloon 30, the
inner tube 40 disposed inside the outer tube 20 and having a distal
end connected to the distal end of the balloon 30, the
protruded-depressed portion 45 formed on the outer periphery of the
inner tube 40, and the core wire 60 disposed between the outer tube
20 and the inner tube 40. The core wire 60 has the bulged portion
80 sandwiched between the outer tube 20 and one of the depressed
portions 45b of the protruded-depressed portion 45. Therefore, a
force can be transmitted from the bulged portion 80 of the core
wire 60 to both the outer tube 20 and the inner tube 40 regardless
of whether the force is generated by pushing or pulling the
proximal end portion of the balloon catheter 10.
[0052] (2) Even if the balloon catheter 10 bends, the bulged
portion 80 of the core wire 60 can move appropriately between the
depressed portions 45b of the protruded-depressed portion 45, and
thus the flexibility of the balloon catheter 10 can be
maintained.
[0053] FIG. 3 also shows a schematic overall view of a balloon
catheter according to the disclosed embodiments. FIG. 4 shows a
partial enlarged view of region B of FIG. 3.
[0054] A balloon catheter 100 shown in FIG. 3 has an inner tube
different from that of the balloon catheter 10 described above.
That is, an inner tube 140 of the balloon catheter 100 has a distal
end portion 140a and a proximal end portion 140b, and is a tubular
body which is inserted coaxially with the outer tube 20. In
particular, the inner tube 140 is inserted into the inner lumen 28
of the distal end outer tube 21 of the outer tube 20. The inner
tube 140 has an inner lumen 141 in which a guide wire not shown in
the figure may be inserted.
[0055] Further, a protruded-depressed portion 145 comprising
protruded portions 145a and depressed portions 145b is formed by
spirally winding, in a longitudinal direction of the balloon
catheter 100, a metal wire 150 with a circular cross section to
form a coil body. The metal wire 150 is wound on an outer periphery
of the inner tube 140 over the entire length of the inner tube 140.
The metal wire 150 is wound with a large pitch such that adjacent
windings of the metal wire 150 are spaced apart from each other
when the balloon catheter 100 is in an unbent state.
[0056] As described above, the metal wire 150 with a circular cross
section is spirally wound in the longitudinal direction of the
balloon catheter 100 to form a coil body having a large pitch in
order to form the protruded-depressed portion 145. However, a resin
wire may instead be used to form the protruded-depressed portion
145, or a metal wire with a rectangular cross section or a resin
wire with a rectangular cross section may instead be used to form
the protruded-depressed portion 145. Further, two or more metal or
resin wires with a circular or rectangular cross section may be
used to form the protruded-depressed portion 145, or one twisted
wire formed by twisting together two or more metal or resin wires
with a circular cross section may be used to form the
protruded-depressed portion 145. Further, two or more twisted wires
formed by twisting together two or more metal or resin wires with a
circular cross section may be used to form the protruded-depressed
portion 145.
[0057] The bulged portion 80 disposed at the distal end portion 60a
of the core wire 60 is sandwiched between the outer tube 20 and one
of the depressed portions 145b of the protruded-depressed portion
145. In a case where the balloon catheter 100 as described above is
used in a procedure for expanding a stenosis site in the coronary
artery of the heart, a pushing and/or pulling force can be
transmitted from the bulged portion 80 of the core wire 60 to both
the outer tube 20 and the inner tube 140, and a kink in the inner
tube 140 can be prevented by utilizing this simple configuration of
the protruded-depressed portion 145 formed by winding the metal
wire 150 around the outer periphery of the inner tube 140 to form a
coil body having a large pitch.
[0058] FIG. 5 shows a schematic overall view of a balloon catheter
according to the disclosed embodiments. FIG. 6 shows a partial
enlarged view of region C of FIG. 5.
[0059] A balloon catheter 200 shown in FIG. 5 has an inner tube
different from that of the balloon catheter 10 described above.
That is, a metal wire 250 with a rectangular cross section is
spirally wound in a longitudinal direction of the balloon catheter
200 on an outer periphery of an inner tube 240 to form a coil body
with a large pitch that covers the entire length of the inner tube
240. A surface of the metal wire 250 is coated with a resin 260 to
form streamlined protrusions and depressions on an outer periphery
of the inner tube 240a long the shape of the metal wire 250 with a
rectangular cross section. The protrusions and depressions form a
protruded-depressed portion 245 comprising protruded portions 245a
and depressed portions 245b. That is, the streamlined protrusions
and depressions correspond to the protruded portions 245a and the
depressed portions 245b, respectively, having smoothed
surfaces.
[0060] As a resin material for forming the coating, a resin such as
polyamide, polyamide elastomer, polyolefin, polyester, or polyester
elastomer, for example, may be used.
[0061] As described above, the metal wire 250 with a rectangular
cross section is spirally wound in the longitudinal direction of
the balloon catheter 200 to form a coil body having a large pitch,
thereby forming the protruded-depressed portion 245. However, a
resin wire may instead be used to form the protruded-depressed
portion 245, or a metal wire with a circular cross section or a
resin wire with a circular cross section may instead be used to
form the protruded-depressed portion 245. Further, two or more
metal or resin wires with a circular or rectangular cross section
may be used to form the protruded-depressed portion 245, or one
twisted wire formed by twisting together two or more metal or resin
wires with a circular cross section may be used to form the
protruded-depressed portion 245. Further, two or more twisted wires
formed by twisting together two or more metal or resin wires with a
circular cross section may be used to form the protruded-depressed
portion 245.
[0062] The bulged portion 80 disposed at the distal end portion 60a
of the core wire 60 is sandwiched between the outer tube 20 and one
of the depressed portions 245b of the protruded-depressed portion
245. In a case where the balloon catheter 200 is used in a
procedure for expanding a stenosis site in the coronary artery of
the heart, the bulged portion 80 can move smoothly, in addition to
the advantageous effects described above, because the surface of
the metal wire 250 of the coil body is coated with the resin 260 so
that the outer periphery of the inner tube 240 forms streamlined
protrusions and depressions along the shape of the metal wire with
a rectangular cross section to form the protruded-depressed portion
245 comprising the protruded portions 245a and the depressed
portions 245b.
[0063] FIG. 7 shows an enlarged view of a main section of a balloon
catheter 300 according to the disclosed embodiments. FIG. 8 shows a
diagram illustrating the movement of a bulged portion 82. The
balloon catheter 300 satisfies the relationship Dc >Da >Db,
wherein Da represents a distance between an inner wall of the outer
tube 20 and a base of each of the depressed portions 245b in a
radial direction of the balloon catheter 300, Db represents a
distance between the inner wall of the outer tube 20 and an apex of
each of the protruded portions 245a in the radial direction of the
balloon catheter 300, and Dc represents an outer diameter of the
bulged portion 82. Therefore, the transferability of a pushing or
pulling force from the core wire 60 to both the inner tube 240 and
the outer tube 20 can be further improved.
[0064] Further, as shown in FIG. 8, when the balloon catheter 300
bends toward the side of the core wire 60 depending on the
serpentine state of a patient's blood vessel, the bulged portion 82
can move to a distally adjacent one of the depressed portions 245b
(toward the left side in the figure) to maintain the flexibility of
the balloon catheter 300. On the other hand, when the balloon
catheter 300 bends toward the opposite side of the core wire 60,
the bulged portion 82 can move to a proximally adjacent one of the
depressed portions 245b (toward the right side in the figure) to
maintain the flexibility of the balloon catheter 300.
[0065] Note that although FIG. 8 describes the movement of the
bulged portion 82 in the distal and proximal directions (toward the
left and right sides of the figure, respectively), it is apparent
that the bulged portion 80 described above can also move in a
similar fashion.
[0066] Note that although the balloon catheters 10, 100, 200, 300
have been described in the context of use for the treatment of a
blood vessel of the heart, they may be used in various procedures
such as those for expanding a blood vessel of a lower limb or for
expanding a dialysis shunt.
[0067] Further, the balloon catheters 10, 100, 200, 300 have the
bulged portion 80, 82 provided at the distal end portion 60a of the
core wire 60. However, the bulged portion 80, 82 may be provided at
a middle portion of the core wire 60.
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