Patent Grant
7837692
1. Field of the Invention
The present invention is directed to a catheter, for example a retrieval or delivery catheter used in medical applications, which has an expandable end portion.
2. Discussion of the Background
Catheters are well known medical devices used to facilitate various medical procedures, such as diagnostic or delivery procedures. Catheter tubes are inserted into a body of a patient for various medical procedures. For example, a catheter may be used in performing diagnostic procedures such as removing a sample from a body site of a patient. The catheter tube is used in this situation as the delivery vehicle for the medical instrument which removes the sample. Further, sophisticated medical implant devices, such as filters and stents, can be delivered and retrieved into and from the body site of the patient using a catheter.
Generally, a catheter has a tube portion which is relatively stiff in both axial and radial directions to allow proper placement of the catheter in the patient's body, but which may be fitted with a distal soft tip which first contacts tissues in the patient. The soft tip is provided to minimise discomfort for the patient when the catheter is inserted into the patient. For example, WO-A-9808562 A describes a catheter with an insert moulded catheter tip. However, there are constraints on the use of such catheters in that such catheters can only be relatively small sized, and thus can only be used to retrieve and deliver relatively small samples and medical devices.
Accordingly, one object of the present invention is to provide a novel catheter which can be used to retrieve larger objects and deliver and retrieve larger medical devices than in the background art.
A further object of the present invention is to provide a novel catheter which can accommodate an article with a slightly larger dimension than that of a main catheter tube itself.
The novel catheter of the present invention achieves these and other objects by including a portion near a distal tip end which is expandable in size in a radial direction to accommodate larger size samples or medical devices. The catheter includes reinforcement means to enhance the axial strength of the tip while facilitating radial expansion of the tip to accommodate an article.
As a further feature, the novel catheter of the present invention can further include reinforcing portions in the expandable portion to enhance strength in the axial direction, while still allowing expansion in the radial direction.
Most preferably the tip is a soft tip of flexible material.
In a preferred embodiment the reinforcement means comprises an extension means extending from the catheter tube portion. Preferably the tip includes a free distal end and the extension means terminates at a position that is axially spaced back from the free end of the tip.
In one embodiment of the invention the extension means comprises at least one extension member extending from said catheter tube portion into said expandable tip.
Preferably the extension means comprises a plurality of extension members extending from said catheter tube portion into said expandable tip. To provide a gradual change in the axial reinforcement preferably said at least one extension member is tapered toward a leading portion of said expandable tip.
Axial reinforcement and radial expansion is facilitated particularly when said plurality of extension members are equi-spaced in the direction of said expandable member.
Preferably said plurality of extension members are tapered toward a leading portion of said expandable member.
For ease of manufacture while providing the desired reinforcement characteristics preferably the number of said plurality of extension members is four.
To provide atraumatic transition to the soft tip preferably said at least one extension member includes a radiused tip. Ideally, said plurality of extension members each include a radiused tip.
In addition, for ease of passage of an article into or out of the tip preferably the tip has a free end which is rounded.
In a preferred embodiment the tip has a free end which is rounded for ease of passage of the tip through a body passageway such as the vasculature.
Preferably the tip comprises a tubular sleeve of flexible material. For ease of manufacture and to provide a smooth transition preferably the sleeve is attached to the catheter tube portion by heating.
Ideally to provide a smooth transition the tip has an outer diameter which is approximately the same dimension as the outer diameter of the catheter tube portion.
In one aspect the invention provides a retrieval catheter for retrieving an article such as a filter comprising a catheter tube portion and a tip extending axially from the catheter tube portion, the tip being flexible relative to the catheter tube portion, characterised in that the catheter includes reinforcement means to enhance the axial strength of the tip while facilitating radial expansion of the tip to accommodate an article in the tip. Usually the article to be retrieved has a larger dimension then that of the normal internal dimension of the tip.
In one embodiment of the invention the tip is movable from a delivery configuration in which the outer diameter of the tip is approximately of the same dimension as the outer diameter of the catheter portion to which it is attached, to an expandable position as an article is received in the tip.
For ease of use, preferably the tip is progressively movable to the expanded position in response to receiving an article in the tip.
The invention also provides a catheter tube portion having a tip extending axially from the catheter tube portion, in which the catheter tube portion includes reinforcement means to enhance the axial strength of the tip while facilitating radial expansion of the tip to accommodate an article in the tip.
The invention will be more clearly understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, wherein:
a) and 3(b) are cross sectional views of the tip portion of the catheter on the lines IIIa-IIIa and IIIb-IIIb respectively of
a) is an exploded view of the tip portion of the catheter of the present invention;
b) is a cross sectional view on an enlarged scale of a distal end of the tip portion of the catheter;
a) to 5(d) are diagrammatic views showing one operation of the catheter; and
Referring to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, and more particularly to
The catheter 2 may also be used to deliver or retrieve another catheter. The catheter portion 2 of
The catheter portion 2 of the present invention further includes an expandable soft tip portion 6 with a distal tip area 6a. The expandable tip 6 is in the form of a sleeve which has an outer diameter which is nominally the same as the outer diameter of the catheter tube portion 5. The distal soft tip area 6a initially contacts tissues of the patient as the catheter tube portion 5 is inserted into the patient, and minimises discomfort in the patient by virtue of its softness. The expandable soft tip portion 6 is flexible in both the axial and radial directions, and particularly is expandable in the radial direction. This expandable tip portion 6 may be made of a radiopaque or non-radiopaque material. Examples of materials for the expandable tip portion 6 include PEBA (polyether block polyamide), nylon, polyurethane or polyethylene.
The expandable portion 6, which as noted above can be formed of a radiopaque or non-radiopaque material such as PEBA, nylon, polyurethane or polyethylene, can be secured to the main catheter tube portion 5 by heating such as by RF (radio frequency) welding the expandable portion 6 to the main catheter tube portion 5. On heating, the extension legs 10 merge into the expandable portion 6.
It will be noted that the expandable soft portion 6 extends distally beyond the axial extent of the extension legs 10 to provide the distal soft tip 6a which is not axially reinforced. The soft tip 6a has a free end that is rounded internally at 23 for ease of passage of an article 3, and is also rounded externally at 24 for ease of atraumatic passage of the tip through a body passageway such as the vasculature.
a) to 5 (d) show the catheter 2 of the present invention in use as a retrieval catheter as an example of one use of catheter 2. As shown in
In this way, this operation in the present invention allows a sample or device 3 which may be larger than the catheter tube portion 5 to be retrieved from a patient. A medical device which may be larger than the catheter tube portion 5 can also be delivered to a patient in a similar manner.
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims the present invention may be practised otherwise than as specifically disclosed therein.
This is a continuation of application Ser. No. 10/383,254 filed Mar. 7, 2003, now U.S. Pat. No. 7,094,243, which is a Continuation Application of U.S. application Ser. No. 09/915,135 filed Jul. 26, 2001, now abandoned, which in turn is a Continuation of PCT Application No. PCT/IE00/00011 filed Jan. 28, 2000. The entire disclosures of the prior applications, application Ser. Nos. 09/915,135 and 10/383,254 are considered part of the disclosure of the accompanying continuation application and are hereby incorporated by reference.
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| Number | Date | Country | |
|---|---|---|---|
| Parent | 10383254 | Mar 2003 | US |
| Child | 11480473 | US | |
| Parent | 09915135 | Jul 2001 | US |
| Child | 10383254 | US | |
| Parent | PCT/IE00/00011 | Jan 2000 | US |
| Child | 09915135 | US |
