CA2035915A1 - Balloon catheter with stretchable shaft - Google Patents
Balloon catheter with stretchable shaftInfo
- Publication number
- CA2035915A1 CA2035915A1 CA002035915A CA2035915A CA2035915A1 CA 2035915 A1 CA2035915 A1 CA 2035915A1 CA 002035915 A CA002035915 A CA 002035915A CA 2035915 A CA2035915 A CA 2035915A CA 2035915 A1 CA2035915 A1 CA 2035915A1
- Authority
- CA
- Canada
- Prior art keywords
- balloon
- main body
- connection piece
- opening
- lumen
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Landscapes
- Media Introduction/Drainage Providing Device (AREA)
Abstract
ABSTRACT
An angioplasty catheter comprising a main body having proximal and distal ends and defining a first lumen extending to the distal end and a second lumen terminating at an opening spaced from the distal end, and a collapsible connection piece in the main body between said opening and the distal end. A
balloon is attached at the ends of the balloon to the main body and contains the opening and the connection piece, and the connection piece collapses axially when the balloon is inflated to minimise energy stored in the main body. This accommodates changes in length of the balloon so that the body will remain straight both during and after inflation of the balloon. A
method of manufacture is also disclosed.
An angioplasty catheter comprising a main body having proximal and distal ends and defining a first lumen extending to the distal end and a second lumen terminating at an opening spaced from the distal end, and a collapsible connection piece in the main body between said opening and the distal end. A
balloon is attached at the ends of the balloon to the main body and contains the opening and the connection piece, and the connection piece collapses axially when the balloon is inflated to minimise energy stored in the main body. This accommodates changes in length of the balloon so that the body will remain straight both during and after inflation of the balloon. A
method of manufacture is also disclosed.
Description
~ t~ ~
This invention relates to angioplasty catheters for use in the treatment of stenosed blood vessels. The invention also relates to a method of manufacturing the catheter.
Angioplasty catheters have been successfully used for a number of years in the treatment of blood vessels obstructed or stenosed with plaque. An angioplasty catheter includes, near its distal end, a balloon which can be inflated by means of pressurized fluid supplied through a lumen in the catheter. The treatment involves the location of the balloon in the stenosed section of the blood vessel, followed by inflation and deflation. During inflation, the balloon compresses the plaque and stretches the blood vessel such that the cross-sectional area of the stenosis is increased until it is comparable to that of the unobstructed blood vessel. When the treatment has been completed the balloon is deflated and the catheter removed. The treated blood vessel maintains substantially its enlarged cross-section to permit the free flow of blood through this portion.
To perform satisfactorily a suitable angioplasty catheter must possess a number of properties. For ease of insertion it is preferable that the catheter is flexible, has a relatively small cross-sectional area, and has a smooth outer surface. The catheter preferably has a tapered end and a main lumen to receive a Seldinger guide wire. The catheter ends at an aperture in the tapered end. A ballon is attached to the catheter near the distal end for inflation by entering a .
' ' - ~ .
J ~, 3~
pressurized fluid into a secondary lumen running in parallel with the main lumen through the body of the catheter.
The balloon must display a small profile during insertion in the collapsed condition, it must inflate evenly to compress the plaque, and then after deflation, the balloon profile should return to the original shape for removal of the catheter without damaging veins.
Examples of typical structures for use in angioplasty are found in U.S. Patent Nos. 4,338,942 to Fogarty, 4,646,719 to Neuman et al, and 4,402,307 to Hanson et al.
A series of unexpected problems have arisen in using balloons in angioplasty. The balloons are usually of a filmic Nylon (trade mark) made to have a cylindrical appearance when infiated and made with a molecular orientation along the length of the balloon. The catheter body extends through the balloon which is attached at its ends to the body. On inflation, the balloon is subject to very high hoop stresses which tend to cause some radial stretching and this causes sympathetic tensile forces longitudinally which place a compressive loading on the body inside the balloon. It is not uncommon that these compressive forces exceed the buckling load of the body and the body takes on a curve or buckle (see Fig. 1) thereby allowing the hoop stresses to exceed the elastic limit of the balloon resulting in some distortion. As a result the balloon is sometimes shorter when it is subsequently deflated and the body then remains in the buckled state (see Fig. 2). This resulting shape is most undesirable for withdrawing the catheter.
It would seem that the problem could be overcome by 3 ~ ~
using a balloon which is longer than the spacing between the connections to the catheter body. Extra material will be available and it was thought that this would allow the balloon to inflate without stressing the catheter. However, this leads to a different problem because the balloon will simply stretch until it induces compression in the body, and also an enlarged balloon tends to lose the desirable cylindrical shape and become spherical. The result is that the loading on the plaque is less than optimal and can cause large localized stresses in the stenosed vein.
It is therefore an object of the present invention to provide a catheter for angioplasty which controls undesirable changes of shape in the balloon and catheter body resulting from balloon inflation.
In one of its aspects the invention provides an angioplasty catheter comprising a main body having proximal and distal ends and defining a first lumen extending to the distal end and a second lumen terminating at an opening spaced from the distal end, and a collapsible connection piece in the main body between said opening and the distal end. A balloon is attached at the ends of the balloon to the main body and contains the opening and the connection piece, and the connection piece collapses axially when the balloon is inflated to minimise energy stored in the main body. This accommodates changes in length of the balloon so that the body will remain straight both during and after inflation of the balloon.
In another of its aspects, a method of making an angioplasty catheter is provided.
This and other aspects of the invention will be better understood with reference to the drawings, in which:
Figs. 1 and 2 are diagrammatic illustrations demonstrating the problem with prior art angioplasty catheters;
Fig. 3 is an isometric view of an angioplasty catheter in accordance with a preferred embodiment of the present invention;
Fig. 4 is an enlarged isometric view of balloon forming part of the catheter;
Fig. 5 is an enlarged sectional view on line 5-5 of Fig. 4;
Fig. 6 is a enlarged sectional view on line 6-6 of Fig.
4; and Fig. 7 is an enlarged sectional view on line 7-7 of Fig. 4.
As previously discussed, prior art balloon structures caused deformation of the catheter body as seen in Figs. 1 and
This invention relates to angioplasty catheters for use in the treatment of stenosed blood vessels. The invention also relates to a method of manufacturing the catheter.
Angioplasty catheters have been successfully used for a number of years in the treatment of blood vessels obstructed or stenosed with plaque. An angioplasty catheter includes, near its distal end, a balloon which can be inflated by means of pressurized fluid supplied through a lumen in the catheter. The treatment involves the location of the balloon in the stenosed section of the blood vessel, followed by inflation and deflation. During inflation, the balloon compresses the plaque and stretches the blood vessel such that the cross-sectional area of the stenosis is increased until it is comparable to that of the unobstructed blood vessel. When the treatment has been completed the balloon is deflated and the catheter removed. The treated blood vessel maintains substantially its enlarged cross-section to permit the free flow of blood through this portion.
To perform satisfactorily a suitable angioplasty catheter must possess a number of properties. For ease of insertion it is preferable that the catheter is flexible, has a relatively small cross-sectional area, and has a smooth outer surface. The catheter preferably has a tapered end and a main lumen to receive a Seldinger guide wire. The catheter ends at an aperture in the tapered end. A ballon is attached to the catheter near the distal end for inflation by entering a .
' ' - ~ .
J ~, 3~
pressurized fluid into a secondary lumen running in parallel with the main lumen through the body of the catheter.
The balloon must display a small profile during insertion in the collapsed condition, it must inflate evenly to compress the plaque, and then after deflation, the balloon profile should return to the original shape for removal of the catheter without damaging veins.
Examples of typical structures for use in angioplasty are found in U.S. Patent Nos. 4,338,942 to Fogarty, 4,646,719 to Neuman et al, and 4,402,307 to Hanson et al.
A series of unexpected problems have arisen in using balloons in angioplasty. The balloons are usually of a filmic Nylon (trade mark) made to have a cylindrical appearance when infiated and made with a molecular orientation along the length of the balloon. The catheter body extends through the balloon which is attached at its ends to the body. On inflation, the balloon is subject to very high hoop stresses which tend to cause some radial stretching and this causes sympathetic tensile forces longitudinally which place a compressive loading on the body inside the balloon. It is not uncommon that these compressive forces exceed the buckling load of the body and the body takes on a curve or buckle (see Fig. 1) thereby allowing the hoop stresses to exceed the elastic limit of the balloon resulting in some distortion. As a result the balloon is sometimes shorter when it is subsequently deflated and the body then remains in the buckled state (see Fig. 2). This resulting shape is most undesirable for withdrawing the catheter.
It would seem that the problem could be overcome by 3 ~ ~
using a balloon which is longer than the spacing between the connections to the catheter body. Extra material will be available and it was thought that this would allow the balloon to inflate without stressing the catheter. However, this leads to a different problem because the balloon will simply stretch until it induces compression in the body, and also an enlarged balloon tends to lose the desirable cylindrical shape and become spherical. The result is that the loading on the plaque is less than optimal and can cause large localized stresses in the stenosed vein.
It is therefore an object of the present invention to provide a catheter for angioplasty which controls undesirable changes of shape in the balloon and catheter body resulting from balloon inflation.
In one of its aspects the invention provides an angioplasty catheter comprising a main body having proximal and distal ends and defining a first lumen extending to the distal end and a second lumen terminating at an opening spaced from the distal end, and a collapsible connection piece in the main body between said opening and the distal end. A balloon is attached at the ends of the balloon to the main body and contains the opening and the connection piece, and the connection piece collapses axially when the balloon is inflated to minimise energy stored in the main body. This accommodates changes in length of the balloon so that the body will remain straight both during and after inflation of the balloon.
In another of its aspects, a method of making an angioplasty catheter is provided.
This and other aspects of the invention will be better understood with reference to the drawings, in which:
Figs. 1 and 2 are diagrammatic illustrations demonstrating the problem with prior art angioplasty catheters;
Fig. 3 is an isometric view of an angioplasty catheter in accordance with a preferred embodiment of the present invention;
Fig. 4 is an enlarged isometric view of balloon forming part of the catheter;
Fig. 5 is an enlarged sectional view on line 5-5 of Fig. 4;
Fig. 6 is a enlarged sectional view on line 6-6 of Fig.
4; and Fig. 7 is an enlarged sectional view on line 7-7 of Fig. 4.
As previously discussed, prior art balloon structures caused deformation of the catheter body as seen in Figs. 1 and
2. The preferred embodiment of the invention is seen in Fig. 3 which shows an angioplasty catheter, designated generally by the numeral 20, including a flexible main body 22 having a distal end 24 defining a tapered tip 25 to facilitate insertion into a vein of a patient, and a proximal end 26 for connection, by means of junction piece 28, to the respective distal ends of a 25 guide wire tube 30 and a fluid supply tube 32. The tubes 30, 32 are in communication with respective circular guide wire and fluid supply lumens 34, 36 defined within the main body 22 (Fig.3) and are provided with luer fittings 35, 37 at the J ~
respective proximal ends.
The body 22 extends from the connection piece 28 to the tip 24 and passes through a transparent Nylon (trade mark) balloon 40, details of which are provlded below. A tubular shipping protector (not shown) for location over the distal end 24 and balloon 40 would normally be provided to protect the balloon and to retain it in a collapsed condition ready for insertion.
As seen in Fig. 4, the transparent balloon 40 is shown inflated and this is achieved by applying fluid pressure to the lumen 32 (Fig. 1) which is available through an opening 42 adjacent the end of this lumen as will be described. The opening 42 is inside the balloon which is attached at its ends 46, 48 to the main body 22. Also within the balloon is an axially collapsable connection piece 47 forming part of the main body and attached to a distal end of a first part 49 of the body and to a proximal end of a second or tip portion 46 as will be more fully described with reference to Fig. 7. Radiopaque bands 50. 53 are applied to the main body as is conventional in the angioplasty art.
The main body 22 has a constant cross-section over the majority of its length as shown in Fig. 5 which also shows the position of opening 42. The main body 22 defines lumens 52, 54 with the lumen 52 being the lumen carrying fluid pressure for inflating the balloon and the main lumen 54 being available for Seldinger insertion and extending all the way to the tip 25.
Immediately adjacent to the opening 42 and towards the tip 25, the portions of the main body 49 and 51 are deformed using heat and a mandril which is placed in the main lumen 54. The purpose of this is to seal off the lumen 52 so that it is closed immediately adjacent the opening 42. Consequently, from the opening 42 forwardly to the tip 25 there is but the main lumen 54 which extends also through the connection piece 47. The resulting circular cross-section shown in Fig. 6 receives the connecion piece as shown in Fig. 7.
Referring now to Fig. 7, the connection piece 47 is tubular, flexible and thin-walled and bonded at its ends to ends of the portions 49, 51 which are slightly tapered to assist in engagement of the piece 47. The body 22 is made initially in one piece without the connection piece 47 and then cut to form the two distinct portions 49 and 51 so that the piece 47 can be engaged. The materials must, of course, be compatable and it is found that a Nylon (trade mark) material sold under the trade mark Pebax is suitable for the purpose.
In use, the assembly is of course entered with the balloon in the collapsed condition and once it has reached the stenosed portion of the vein, and located by conventional use of the opaque bands 50, 53, fluid pressure is applied to the lumen 52 (Fig. 5) and, because of the opening 42, this pressure is applied inside the balloon to inflate it. As mentioned with reference to the prior art, there is a tendency for the balloon to expand radially bringing the ends 46, 48 (Fig. 4) of the balloon towards one another. This can be accommodated by the connection piece 47 which because of its inherent flexibility will simply deform so that there is no reaction to this load created by the balloon. The balloon will then stiffen and remain in the cylindrical shape shown in Fig. 4. After use, and if the balloon has stretched, the balloon will nevertheless collapse back to its essentially original condition, because if it has shrunk longitudinally, this shrinkage is accommodated in the piece 47. Consequently the problems demonstrated with reference to Figs. 1 and 2 are obviated.
The catheter is manufactured by first providing an extrusion for the body 22 and then, after cutting the body to form the portions 49, 51 shown in Fig. 4, the connection piece 47 is assembled and bonded in place. The tip 25 is formed conventionally using a cylindrical internal mandrel and a tapered external mandrel and the body is attached to the junction piece 28 shown in Fig. 3 where the tubes 30, 32 are assembled at the same time. After this is done the hole 42 is formed into the lumen 52 and the balloon is engaged. Preferably the integrity of the main body is ensured by using a mandrel in the lumen 54 while this assembly takes place and then the ends 46, 48 of the balloon are bonded to the main body.
It will be evident that the principles behind the invention can be reduced to a number of different forms, all within the scope of the claims.
respective proximal ends.
The body 22 extends from the connection piece 28 to the tip 24 and passes through a transparent Nylon (trade mark) balloon 40, details of which are provlded below. A tubular shipping protector (not shown) for location over the distal end 24 and balloon 40 would normally be provided to protect the balloon and to retain it in a collapsed condition ready for insertion.
As seen in Fig. 4, the transparent balloon 40 is shown inflated and this is achieved by applying fluid pressure to the lumen 32 (Fig. 1) which is available through an opening 42 adjacent the end of this lumen as will be described. The opening 42 is inside the balloon which is attached at its ends 46, 48 to the main body 22. Also within the balloon is an axially collapsable connection piece 47 forming part of the main body and attached to a distal end of a first part 49 of the body and to a proximal end of a second or tip portion 46 as will be more fully described with reference to Fig. 7. Radiopaque bands 50. 53 are applied to the main body as is conventional in the angioplasty art.
The main body 22 has a constant cross-section over the majority of its length as shown in Fig. 5 which also shows the position of opening 42. The main body 22 defines lumens 52, 54 with the lumen 52 being the lumen carrying fluid pressure for inflating the balloon and the main lumen 54 being available for Seldinger insertion and extending all the way to the tip 25.
Immediately adjacent to the opening 42 and towards the tip 25, the portions of the main body 49 and 51 are deformed using heat and a mandril which is placed in the main lumen 54. The purpose of this is to seal off the lumen 52 so that it is closed immediately adjacent the opening 42. Consequently, from the opening 42 forwardly to the tip 25 there is but the main lumen 54 which extends also through the connection piece 47. The resulting circular cross-section shown in Fig. 6 receives the connecion piece as shown in Fig. 7.
Referring now to Fig. 7, the connection piece 47 is tubular, flexible and thin-walled and bonded at its ends to ends of the portions 49, 51 which are slightly tapered to assist in engagement of the piece 47. The body 22 is made initially in one piece without the connection piece 47 and then cut to form the two distinct portions 49 and 51 so that the piece 47 can be engaged. The materials must, of course, be compatable and it is found that a Nylon (trade mark) material sold under the trade mark Pebax is suitable for the purpose.
In use, the assembly is of course entered with the balloon in the collapsed condition and once it has reached the stenosed portion of the vein, and located by conventional use of the opaque bands 50, 53, fluid pressure is applied to the lumen 52 (Fig. 5) and, because of the opening 42, this pressure is applied inside the balloon to inflate it. As mentioned with reference to the prior art, there is a tendency for the balloon to expand radially bringing the ends 46, 48 (Fig. 4) of the balloon towards one another. This can be accommodated by the connection piece 47 which because of its inherent flexibility will simply deform so that there is no reaction to this load created by the balloon. The balloon will then stiffen and remain in the cylindrical shape shown in Fig. 4. After use, and if the balloon has stretched, the balloon will nevertheless collapse back to its essentially original condition, because if it has shrunk longitudinally, this shrinkage is accommodated in the piece 47. Consequently the problems demonstrated with reference to Figs. 1 and 2 are obviated.
The catheter is manufactured by first providing an extrusion for the body 22 and then, after cutting the body to form the portions 49, 51 shown in Fig. 4, the connection piece 47 is assembled and bonded in place. The tip 25 is formed conventionally using a cylindrical internal mandrel and a tapered external mandrel and the body is attached to the junction piece 28 shown in Fig. 3 where the tubes 30, 32 are assembled at the same time. After this is done the hole 42 is formed into the lumen 52 and the balloon is engaged. Preferably the integrity of the main body is ensured by using a mandrel in the lumen 54 while this assembly takes place and then the ends 46, 48 of the balloon are bonded to the main body.
It will be evident that the principles behind the invention can be reduced to a number of different forms, all within the scope of the claims.
Claims (8)
OR PRIVILEDGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An angioplasty catheter comprising:
a main body having proximal and distal ends and defining a first lumen extending to the distal end and a second lumen terminating at an opening spaced from the distal end, and a collapsible connection piece in the main body between said opening and the distal end;
a balloon attached at the ends of the balloon to the main body and containing said opening and the connection piece;
and the connection piece being collapsible axially when the balloon is inflated to minimise energy stored in the main body to thereby accommodate changes in length of the balloon so that the body will tend to remain straight both during and after inflation of the balloon.
a main body having proximal and distal ends and defining a first lumen extending to the distal end and a second lumen terminating at an opening spaced from the distal end, and a collapsible connection piece in the main body between said opening and the distal end;
a balloon attached at the ends of the balloon to the main body and containing said opening and the connection piece;
and the connection piece being collapsible axially when the balloon is inflated to minimise energy stored in the main body to thereby accommodate changes in length of the balloon so that the body will tend to remain straight both during and after inflation of the balloon.
2. An angioplasty catheter as claimed in claim 1 in which the main body is circular in cross-section.
3. An angioplasty catheter as claimed in claim 2 in which the main body between said opening and the distal end is circular in cross-section.
4. An angioplasty catheter as claimed in claim 1 in which the connection piece is thin walled and tubular.
5. An angioplasty catheter as claimed in claim 1 and further comprising at least one radiopaque band around the body inside the balloon.
6. In an angioplasty catheter of the type having a dual lumen main body and a balloon on the main body to be inflated by fluid pressure applied to one of the lumens, the improvement in which the main body includes a collapsible connection piece inside the balloon for collapsing axially when the balloon is inflated to minimise energy stored in the main body to thereby accommodate changes in length of the balloon so that the body will tend to remain straight both during and after inflation of the balloon.
7. Structure as claimed in claim 6 in which the main body and balloon have circular cross-sections.
8. A method of making an angioplasty catheter comprising the steps:
providing a dual lumen longer first portion, a tubular shorter second portion, and a collapsible tubular connection piece;
forming an end of the first portion to close one end of one of the lumens and forming an opening in this portion leading to the closed lumen adjacent the closed end;
engaging the connection piece on said one end of the first portion and on an end of the second portion and sealing the piece to these portions with the portions spaced apart to form a main body.
affixing a balloon about the main body to contain the coupling piece and said opening so that fluid pressure in the closed lumen will inflate the balloon and the connection piece will permit axial contraction of the balloon without stressing the main body significantly.
providing a dual lumen longer first portion, a tubular shorter second portion, and a collapsible tubular connection piece;
forming an end of the first portion to close one end of one of the lumens and forming an opening in this portion leading to the closed lumen adjacent the closed end;
engaging the connection piece on said one end of the first portion and on an end of the second portion and sealing the piece to these portions with the portions spaced apart to form a main body.
affixing a balloon about the main body to contain the coupling piece and said opening so that fluid pressure in the closed lumen will inflate the balloon and the connection piece will permit axial contraction of the balloon without stressing the main body significantly.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002035915A CA2035915A1 (en) | 1991-02-07 | 1991-02-07 | Balloon catheter with stretchable shaft |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002035915A CA2035915A1 (en) | 1991-02-07 | 1991-02-07 | Balloon catheter with stretchable shaft |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2035915A1 true CA2035915A1 (en) | 1992-08-08 |
Family
ID=4146973
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002035915A Abandoned CA2035915A1 (en) | 1991-02-07 | 1991-02-07 | Balloon catheter with stretchable shaft |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2035915A1 (en) |
-
1991
- 1991-02-07 CA CA002035915A patent/CA2035915A1/en not_active Abandoned
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Dead |