Patent Application
20140257130
The present disclosure relates to medical devices and their methods of use. More specifically, the present disclosure relates to catheters having one or more elements at the distal end that are electrically connected proximally, and also having a pull wire for actuating a distal portion of the catheter. One example of such a device is a powered ablation catheter with a pull wire.
A wide variety of intracorporeal medical devices have been developed for medical use, for example, intravascular use. Some of these devices include guidewires, catheters, and the like. These devices are manufactured by any one of a variety of different manufacturing methods and may be used according to any one of a variety of methods. Of the known medical devices and methods, each has certain advantages and disadvantages. There is an ongoing need to provide alternative medical devices as well as alternative methods for manufacturing and using medical devices.
Medical devices and methods for making and using medical devices are disclosed.
In general, the embodiments described herein use a powered pull wire, which is to say that one wire is configured to be suitable for use both as a pull wire and as a wire for electrical conduction. A pull wire may be made suitable for use as a wire for electrical conduction by providing a conductive cladding over the pull wire.
For example, one embodiment relates to a pull wire ablation catheter that includes a thermocouple sensor. The pull wire has, for example, a stainless steel core and a copper cladding. The cladding is electrically connected to an ablation element and to a thermocouple joint. Another wire extends proximally from the thermocouple joint.
Another embodiment relates to a pull wire ablation catheter that includes a thermistor. The pull wire has, for example, a stainless steel core and a copper or gold cladding. Two other wires extend proximally from the thermistor or the ablation element. One of the cladding and the two wires is electrically connected to the ablation element and the other two of the cladding and the two wires are electrically connected to the thermistor.
The above summary of some example embodiments is not intended to describe each disclosed embodiment or every implementation of the invention.
The disclosure may be more completely understood in consideration of the following detailed description of various embodiments in connection with the accompanying drawings, in which:
The above summary of some embodiments is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The Figures, and Detailed Description, which follow, more particularly exemplify these embodiments.
For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification.
All numeric values are herein assumed to be modified by the term “about”, whether or not explicitly indicated. The term “about” generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (i.e., having the same function or result). In many instances, the term “about” may be indicative as including numbers that are rounded to the nearest significant figure.
The recitation of numerical ranges by endpoints includes all numbers within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).
Although some suitable dimensions, ranges and/or values pertaining to various components, features and/or specifications are disclosed, one of skill in the art, incited by the present disclosure, would understand desired dimensions, ranges and/or values may deviate from those expressly disclosed.
As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.
The following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The detailed description and the drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the invention. The illustrative embodiments depicted are intended only as exemplary. Selected features of any illustrative embodiment may be incorporated into an additional embodiment unless clearly stated to the contrary.
A pull wire or a control wire may be in deflectable catheters to change the shape of the distal end or to deflect the distal end of the catheter in situ by pulling on a proximal portion of a pull wire operatively connected to the distal end region of the catheter. Pull wires may be made from stainless steel and may have a diameter ranging from 0.007″ to 0.012″, depending on the required pull force. Deflectable ablation catheters may also contain multiple other wires such as power wires, sensing wires and thermal sensing wires. For a catheter having a diameter of 7 French or greater, fitting the required wires into the lumen of the catheter is not normally an issue. However, for catheters that are miniaturized for use in smaller spaces, the dimension of the catheter lumen may become a limiting design consideration.
Turning now to
The core 26 of the pull wire 24 should be suitable for use as a pull wire. Adequate tensile strength and anti-stretchability are two characteristics of a pull wire. Tensile strength refers to the maximum force in tension that the pull wire core can withstand. Anti-stretchability refers to the resistance to elongation of the material. A material with more resistance to stretching has a higher modulus of elasticity. Both properties, as discussed herein, are understood to be functions of the material(s), amount of materials and configuration. A suitable core 26 may be made from a solid stainless steel wire or from a cable made from strands of stainless steel.
The cladding 28 is used to conduct electricity. Suitable materials have a high conductivity. Copper and gold are suitable materials. Because the cladding is a layer on a core 26, the cladding can be quite thin and still be suitable for conducting electricity. In other words, the cross-sectional area of a pull wire core can be increased only slightly and provide equivalent electrical conduction to a separate wire much thicker than the cladding layer. For example, a pull wire having a 0.008″ stainless steel core with a cladding of 0.0005″ has lower resistance than a copper wire of diameter 0.004″. The cross-sectional area of the copper of the pull wire is greater than that of the solid copper wire. It can be appreciated that other configurations may be suitable for use as a combination pull wire and conductor. For example, the dimensions of the core and the cladding may be varied to meet desired engineering requirements. A 0.008″ stainless steel core with a 0.001″ copper cladding may be suitable in some applications. In other applications, the core may be made from the conductive material, and the cladding may be the less conductive layer having higher tensile strength. One example combination pull wire and conductor has a 0.003″ silver core with a 0.003″ stainless steel cladding. The cross-sectional dimensions of the core and the cladding determine their electrical resistance and yield strength.
Thus in one instance,
In alternative embodiments, the pull wire 24 may not be connected directly to the ablation element. The pull wire 24 may be attached to another structural element at or near the distal tip such as a pull ring. In such embodiments, an electrical conductor such as a short wire may need to extend distally of the pull wire to electrically connect pull wire to the ablation element or the pull wire may be mechanically connected to the pull ring or other structural element and extend distally past the pull ring to electrically connect to the ablation element.
At the proximal end of the catheter 10, the conductive elements such as cladding 26 and wires 34, 42 and 44 may be connected electrically to the power and control unit 22 through the hub or other suitable means. It will be appreciated that the cladding 26, because it is a part of pull wire 24, may move relative to the hub. A flexible wire that has enough play may therefore be placed between the pull wire and the hub to accommodate this movement. Other suitable methods of electrically connecting the pull wire to the power and control unit are also contemplated.
It will be appreciated that the use of a clad pull wire as described herein may readily be adapted to any medical device having a pull wire and a therapeutic element requiring electrical connectivity. It can also be appreciated that in devices that include more than one pull wire, each pull wire may be clad and used as an electrical wire as described herein. Further, there are catheters that include one or more stiffeners; it can be appreciated that these stiffeners may be clad and used as electrical elements. In other words, though the embodiments are described with respect to the combination of an actuatable pull wire and an electrical wire, embodiments are contemplated in which the “pull wire” is a fixed member.
In use, such a catheter 10 may be introduced percutaneously as is conventional, as for example, through a guide catheter. The pull wire may be actuated to deflect the distal end to aid in steering the catheter to the desired location within the body. When in place, the ablation element 16 is activated as desired. The catheter 10 may be repositioned and the procedure repeated.
It should be understood that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of steps without exceeding the scope of the disclosure. This may include, to the extent that it is appropriate, the use of any of the features of one example embodiment being used in other embodiments. The invention's scope is, of course, defined in the language in which the appended claims are expressed.
This application claims priority under 35 U.S.C. §119 to U.S. Provisional Application Ser. No. 61/776,613, filed Mar. 11, 2013, the entirety of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61776613 | Mar 2013 | US |
