Surgery – Instruments – Internal pressure applicator
Reexamination Certificate
2001-04-03
2003-09-02
Milano, Michael J. (Department: 3731)
Surgery
Instruments
Internal pressure applicator
C606S194000, C606S198000, C604S096010
Reexamination Certificate
active
06613066
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a balloon catheter used primarily in medical treatment and surgery for the purpose of dilating lesion sites such as strictures or blockages in passages in the body, and more particularly to a balloon catheter, and method for manufacturing a balloon catheter, used in percutaneous translumin angioplasty (PTA) or percutaneous translumin coronary angioplasty (PTCA), which are treatments for dilating lesion sites such as strictures or blockages in coronary arteries, extremital arteries, kidney arteries, and peripheral blood vessels, etc.
2. Description of the Related Art
The common balloon catheter is formed by joining a balloon that is expanded and contracted by adjusting the internal pressure therein to the distal end of a catheter shaft, wherein, in the interior of the catheter shaft, are formed, extending in the axial direction thereof, a lumen (guide wire lumen) for inserting therein a guide wire, and a lumen (inflation lumen) for passing a pressurized fluid that is supplied for adjusting the inner pressure in the balloon. Using such a balloon catheter as this, angioplasty is performed according to the procedure now described. First, the guide wire passed through the guide wire lumen is made to pass through the stricture or other lesion site, the balloon is inserted into the body along that guide wire and made to coincide with the lesion site, a pressured fluid such as a suitably diluted shadow-casting agent is supplied through the inflation lumen to the balloon, the balloon is caused to expand, and the lesion site is subjected to dilation therapy. After the lesion site has been subjected to the dilation therapy, the balloon is first made to contract by reducing the pressure therein and folded, and then removed from the body, whereupon the angioplasty is finished.
Such balloon catheters as these are divided into two types, namely in over-the-wire type balloon catheter wherein a tube
200
for passing the guide wire is deployed so that it reaches from an adapter member
202
connected to the base end of the catheter shaft
201
to the distal end of the balloon
203
, as exemplified in
FIG. 27
, and a rapid exchange type balloon catheter wherein a tube
210
for passing the,guide wire is deployed so that its reach is limited from midway along the catheter shaft
211
to the distal end of the balloon
212
, as exemplified in FIG.
28
. In
FIG. 27 and 28
, the distal part containing the balloon is represented slightly enlarged over the near portion to facilitate understanding.
The over-the-wire balloon catheter diagrammed in
FIG. 27
is configured with a catheter shaft
201
formed by the joining of a tube
204
on the distal side and a tube
205
on the proximal side, a balloon
203
joined to the distal end of the tube
204
on the distal side, and the adapter member
202
joined at the base end of the tube
205
on the proximal side.
The structure of the distal part of such a balloon catheter is exemplified in FIG.
29
(
a
). The guide wire passing tube
200
having a guide wire lumen
200
a
is passed through the inner space of the balloon
203
. The inner circumferential surface of a sleeve part
203
a
on the distal side of this balloon
203
and the outer circumferential surface of the guide wire passing tube
200
are joined concentrically with an adhesive
206
. And the inner circumferential surface of a sleeve part
203
b
on the proximal side of the balloon
203
and the outer circumferential surface at the distal end of the outside tube
204
are joined concentrically with an adhesive
207
. Symbol
208
in this figure designates a radiopaque marker. Also, as diagrammed in the A
1
-A
2
cross-section in FIG.
29
(
b
), the guide wire passing tube
200
and outside tube
204
are deployed concentrically, and an inflation lumen
209
for passing the pressurized fluid supplied to the balloon
203
is formed between the inner surface of the outside tube
204
and the outer surface of the guide wire passing tube
200
. Although, in this example, the guide wire passing tube
200
and outside tube
204
are deployed concentrically, there are also configurations wherein the outer circumferential surface at the distal end of the guide wire passing tube
200
is bonded securely to the inner surface of the outside tube
204
so that the guide wire passing tube
200
will not move backwards relative to the outside tube
204
such that the relative position therebetween shifts greatly.
There is also another distal part structure, such as exemplified in FIG.
30
. According to
FIG. 30
, a guide wire passing tube
214
configuring a guide wire lumen
214
a
and an inflation tube
210
configuring an inflation lumen
210
a
are deployed in parallel. As diagrammed in the B
1
-B
2
cross-section in FIG.
30
(
b
), both tubes are secured by a heat-shrunk tube
215
to configure a catheter shaft
211
. Also, the inner circumferential surface of the sleeve part
212
a
is bonded to the outer circumferential surface on the distal end of the guide wire passing tube
214
with an adhesive
216
, and the inner circumferential surface of the sleeve part
212
b
on the proximal side of the balloon
212
and the outer circumferential surface of the catheter shaft
211
are bonded with an adhesive
217
. The symbols
218
A and
218
B in this figure indicate radiopaque markers. There is yet another distal part configuration, such as that diagrammed in FIG.
31
. In the C
1
-C
2
cross-section in FIG.
31
(
b
) is diagrammed a catheter shaft
211
consisting of a single-structure tube-shaped member
219
comprising a guide wire shaft
214
and inflation lumen
219
a
internally.
The rapid exchange type balloon catheter diagrammed in
FIG. 28
, on the other hand, has a catheter shaft
211
comprising a tube shaped member, configured such that the balloon
212
is joined to the distal end of that catheter shaft
211
, the adapter member
213
is joined to the base end of the catheter shaft
211
, and a guide wire passing tube
210
also deployed in the distal part.
In general, in the interest of smooth insertion into a passage in the body and reaching the most distant site along that internal passage, balloon catheters having smaller outer diameters are advantageous. That being so, unused balloon catheters are commonly provided in a condition wherein the balloon has been made to contract under reduced pressure and folded up to minimize the outer diameter of the balloon.
The properties required as minimal limitations in such balloons are (1) that they be able to withstand pressures sufficiently so that they do not burst when the inner pressure is increased by a pressurized fluid, (2) that they exhibit a predetermined relationship between the expanded outer diameter and the expansion pressure (expansion characteristics), and (3) that the strength of the balloon in the circumferential direction and axial direction be calculated in a balanced manner so that the balloon can exhibit deformation so as to conform to winding internal passages when expanded. It is also preferable that the skin thickness of the balloon itself be as thin as possible in order to make the outer shape of the balloon small when it is folded up.
Balloon catheters, moreover, are often used a number of times for the same lesion site. In such cases, from the perspective of reintroducing the balloon catheter, it is important that the balloon exhibit the property of being able to retain well the condition wherein it is made to contract under reduced pressure and folded up (folded shape retention characteristics). Also, the skin thickness of the straight tubular part of the balloon should be as thin as possible so that it has a small outer diameter in the folded condition, and the skin thickness in the conical parts or sleeve parts of the balloon should also be as thin as possible, for the same reasons, but also to realize good reintroduction performance toward the lesion site when reused. That the balloon exhibit good fold-up retention, thin skin in the st
Fukaya Kohei
Hashiba Masato
Maeda Hiromi
Miki Shogo
Nakano Ryoji
Armstrong Westerman & Hattori, LLP
Kaneka Corporation
Milano Michael J.
Phanijphand Gwen
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