Composite guidewire

Alternative designs, materials and manufacturing methods for guidewires. Some embodiments pertain to a composite guidewire having proximal and distal section, and a connector adapted and configured for permanently joining the proximal section to the distal section. In some embodiments, at least one of the sections is made of a linear-elastic nickel-titanium alloy. Several alternative guidewire tip designs including coiled safety/shaping structures are also disclosed.

FIELD OF THE INVENTION

The invention generally pertains to intravascular guidewires.

BACKGROUND OF THE INVENTION

A wide variety of guidewires have been developed for intravascular use. Intravascular guidewires are commonly used in conjunction with intravascular devices such as catheters to facilitate navigation through the vasculature of a patient. Because the vasculature of a patient may be very tortuous, it is desirable to combine a number of performance features in an guidewire. For example, it is sometimes desirable that the guidewire have a relatively high level of pushability and torqueability, particularly near its proximal end. It is also sometimes desirable that a guidewire be relatively flexible, particularly near its distal end. A number of different guidewire structures and assemblies are known, each having certain advantages and disadvantages. However, there is an ongoing need to provide alternative guidewire structures and assemblies.

SUMMARY OF THE INVENTION

The invention provides several alternative designs, materials and methods of manufacturing alternative guidewire structures and assemblies.

DETAILED DESCRIPTION OF THE INVENTION

The following description should be read with reference to the drawings wherein like reference numerals indicate like elements throughout the several views. The detailed description and drawings illustrate examples of various embodiments of the claimed invention, and are not intended to be limiting.

Refer now toFIGS. 1–5which illustrate cross sectional views of a portion of a guidewire10including a connection20joining a proximal guidewire section14and a distal guidewire section16.FIG. 1illustrates the guidewire10and the connection20before a final grinding step, andFIG. 2illustrates the guidewire10and the connection20after the final grinding step, which provides a smooth outer profile. The embodiment ofFIGS. 1 and 2utilizes an overlapping tapered joint12and a tubular connector18.

The embodiment ofFIG. 3is similar to the embodiment ofFIGS. 1 and 2, except that the connection20between the proximal guidewire section14and the distal guidewire section16does not utilize a connector tube18, but rather utilizes a connector material19. The embodiment ofFIG. 4is similar to the embodiment ofFIGS. 1and2, except that the connection20between the proximal guidewire section14and the distal guidewire section16does not utilize an overlapping joint12, but rather uses a butt joint13. The embodiment ofFIG. 5is also similar to the embodiment ofFIGS. 1 and 2, except that the connection20between the proximal guidewire section14and the distal guidewire section16utilizes an overlapping joint12that is not tapered.

Those of skill in the art and others will recognize that the materials, structure, and dimensions of the proximal/distal guidewire sections14/16are dictated primary by the desired characteristics and function of the final guidewire, and that any of a broad range of materials, structures, and dimensions can be used.

For example, the proximal and distal guidewire sections14/16may have a solid cross-section as shown, or a hollow cross-section, and may be formed of any materials suitable for use, dependent upon the desired properties of the guidewire. Some examples of suitable materials include metals, metal alloys, and polymers. In some embodiments, it is desirable to use metals, or metal alloys that are suitable for metal joining techniques such as welding, soldering, brazing, crimping, friction fitting, adhesive bonding, etc. As used herein, the proximal section14and the distal section16may generically refer to any two adjacent guidewire sections along any portion of the guidewire. Furthermore, although discussed with specific reference to guidewires, the invention may be applicable to almost any intravascular device. For example, the invention may be applicable to hypotube shafts for intravascular catheters (e.g., rapid exchange balloon catheters, stent delivery catheters, etc.) or drive shafts for intravascular rotational devices (atherectomy catheters, IVUS catheters, etc.).

In some embodiments, the proximal guidewire section14may be formed of relatively stiff material such as straightened 304v stainless steel wire. Alternatively, proximal portion14may be comprised of a metal or metal alloy such as a nickel-titanium alloy, nickel-chromium alloy, nickel-chromium-iron alloy, cobalt alloy, or other suitable material. In general, the material used to construct proximal portion14may be selected to be relatively stiff for pushability and torqueability.

In some embodiments, the distal guidewire section16may be formed of a relatively flexible material such as a straightened super elastic or linear elastic alloy (e.g., nickel-titanium) wire, or a alternatively, a polymer material, such as a high performance polymer. Alternatively, distal portion16may be comprised of a metal or metal alloy such as stainless steel, nickel-chromium alloy, nickel-chromium-iron alloy, cobalt alloy, or other suitable material. In general, the material used to construct distal portion16may be selected to be relatively flexible for trackability.

In some particular embodiments, the distal section16is a linear elastic nickel-titanium alloy, for example, linear elastic nitinol. The word nitinol was coined by a group of researchers at the United States Naval Ordinance Laboratory (NOL) who were the first to observe the shape memory behavior of this material. The word nitinol is an acronym including the chemical symbol for nickel (Ni), the chemical symbol for titanium (Ti), and an acronym identifying the Naval Ordinance Laboratory (NOL).

Within the family of commercially available nitinol alloys, is a category designated “linear elastic” which, although is similar in chemistry to conventional shape memory and superelastic varieties, exhibits distinct and useful mechanical properties. By skilled applications of cold work, directional stress, and heat treatment, the wire is fabricated in such a way that it does not display a “superelastic plateau” or “flag region” in its stress/strain curve. Instead, as recoverable strain increases, the stress continues to increase in an essentially linear relationship until plastic deformation begins. In some embodiments, the linear elastic nickel-titanium alloy is an alloy that does not show any martensite/austenite phase changes that are detectable by DSC and DMTA analysis over a large temperature range. For example, in some embodiments, there is no martensite/austenite phase changes detectable by DSC and DMTA analysis in the range of about −60° C. to about 120° C. The mechanical bending properties of such material are therefore generally inert to the effect of temperature over this very broad range of temperature. In some particular embodiments, the mechanical properties of the alloy at ambient or room temperature are substantially the same as the mechanical properties at body temperature. In some embodiments, the use of the linear elastic nickel-titanium alloy for the distal portion16allows the guidewire to exhibit superior “pushability” around tortuous anatomy.

In some embodiments, the linear elastic nickel-titanium alloy comprises in the range of about 50 to about 60 wt. % nickel, with the remainder being essentially titanium. In some particular embodiments, the composition comprises in the range of about 54 to about 57 wt. % nickel. One example of a suitable nickel-titanium alloy is FHP-NT alloy commercially available from Furukawa Techno Material Co. of Kanagawa, Japan.

In some particular embodiments, the proximal guidewire section14is formed from a stainless steel wire having a diameter in the range of 0.01 to 0.02 inches, and a length in the range of about 50 to about 110 inches, and the distal guidewire section16is formed from a linear elastic nitinol wire having a diameter that ranges from a diameter to match the diameter of the proximal guidewire section14to as small as about 0.002 inches, and a length in the range of 3 to 15 inches.

The distal end24of the proximal portion14and the proximal end26of distal portion16(i.e., the joined ends) may form an overlapping tapered joint12as shown inFIGS. 1–3. Alternatively, the joined ends24/26may form a butt joint13as shown inFIG. 4. As a further alternative, the joined ends24/26may form an overlapping joint12that is not tapered as shown inFIG. 5. The non-tapered end portions24/26may have a uniform profile (diameter)23as shown inFIG. 6A, a bulbous portion25for purposes of mechanical interlocking as shown inFIG. 6B, or a helical form27for purposes of mechanical interlocking as shown inFIG. 6C. In each of the embodiments illustrated inFIGS. 1–3and5, the end portions24/26overlap to form an overlapping joint12. The overlapping joint12blends the stiffness of proximal portion14and distal portion16by combining the properties of each end section24/26making up the cross section of the overlapping joint12. Thus, the joint12forms a flexibility transition region that has a relative flexibility that is between the flexibility of the proximal portion14and the flexibility of the distal portion16.

In the tapered embodiments illustrated inFIGS. 1–3, the ends24/26may be tapered or otherwise formed to have a mating geometry that gradually decreases in cross sectional area toward the middle of the connection20. The tapered overlapping portion12may define a uniform or a non-uniform transition of the sections24/26, depending on the transition characteristics desired. For example, the end sections24/26may be linearly tapered as shown, tapered in a curvilinear fashion, or tapered in a step-wise fashion. If tapered linearly as shown, the angle of the taper may vary. Using the longitudinal center axis of the guidewire10as a reference, as measured from the extreme ends of the end sections24/26, the angle of the taper is acute (i.e., less than 90 degrees), and may be in the range of 5 degrees to 45 degrees, for example. Varying the angle of the tapered ends24/26also varies the length of the overlapping joint12in accordance with geometric principles. The length of the overlapping joint12may be selected to obtain a more (longer length) or less (shorter length) gradual transition in stiffness.

As mentioned previously, the proximal guidewire section14and the distal guidewire section16may be formed of different materials (i.e., materials having different moduli of elasticity) resulting in a difference in flexibility. For example, the proximal guidewire section14may be formed of stainless steel wire and the distal guidewire section16may be formed of nickel-titanium alloy wire, both having the same dimensions, resulting in a 3:1 difference in elastic modulus. Such a difference in elastic modulus (i.e., flexibility) may result in a stress concentration point during flexure and/or torsion that may have a tendency to kink and fracture. By virtue of the gradual transition in stiffness provided by the overlapping portion12, stress is distributed along the entire length of the connection20thereby decreasing the probability that guidewire10may kink at the junction.

A gradual transition in stiffness may also allow the connection20to be located further distally. According to this embodiment, the distal portion16may be manufactured to be shorter than proximal portion14. Including a relatively long proximal section14may advantageously increase the torquability and pushability of the guidewire10. Although only one connection20is shown, additional connections20may be used to connect other guidewire sections of varying stiffness.

The connector18may comprise a tubular structure such as a hypotube as shown or a coiled wire. The connector18may have an inside diameter sized appropriately to receive the ends24/26of the proximal portion14and the distal portion16, and an outside diameter sufficient to accommodate a final grinding procedure. In some example embodiments, the connector18can have an inner diameter in the range of about 0.005 to about 0.02 inches, and an outer diameter in the range of about 0.01 to about 0.025 inches. In some particular embodiments, the connector18can have and inner diameter of about 0.010 inches and an outer diameter of about 0.014 inches. The final diameter of the guidewire10and the connector18may be in the range of 0.010 to 0.018 inches, for example. By way of example, not limitation, the connector18may have a length of about 1.0 to 3.0 inches for an overlapping portion12of about 0.25 to 2.5 inches. However, in some other embodiments, this type of construction can be applied to wires of larger diameter intended, for example, for peripheral intervention purposes. Such wires could range as large as 0.035 in diameter and therefore have an extended length connector and correspondingly longer overlapping sections.

The connector18may be comprised of a metal or metal alloy, and may include radiopaque materials. Suitable metals and metal alloys include stainless steels, nickel-titanium alloys (e.g., nitinol), nickel-chromium alloys, nickel-chromium-iron alloys, cobalt alloys, nickel, or other suitable materials. Alternatively, connector18may be comprised of a polymer or a metal-polymer composite, including a radiopaque filler.

Some types of alloys are particularly suitable for connector18for purposes of connecting a stainless steel proximal section14and a nickel titanium alloy distal section16, or visa-versa. An example is a nickel-chromium-iron alloy designated UNS N06625 and is available under the trade name INCONEL 625, which advantageously welds to both stainless steels and nickel-titanium alloys. INCONEL 625 wire may be obtained from California Fine Wire Company of Grover Beach, Calif., and has the following typical composition:

Another example of a suitable alloy which welds to both stainless steels and nickel-titanium alloys is designated UNS 10276 and is available under the trade name ALLOY C276 from Fort Wayne Metals Research Products Corporation of Fort Wayne, Ind., which has the following typical composition:

Another example of a suitable alloy which welds to both stainless steels and nickel-titanium alloys is of the Hastelloy family and an example of which is available under the trade name ALLOY B2 from Fort Wayne Metals Research Products Corporation of Fort Wayne, Ind., which has the following typical composition:

To manufacture the connection20of the guidewire10, the ends24/26of the proximal and distal guidewire sections14/16may be ground to form the desired shape (e.g., uniform diameter23, bulbous portion25, helix27, or taper) to accommodate the overlapping joint12. If a butt joint13is to be used, such a shape need not be ground. A recess step may be ground into the proximal and distal guidewire sections14/16to accommodate the connector tube18. If a connector tube18is not to be used, such a recess step need not be ground.

For the embodiments utilizing a connector tube18, the connector tube18is positioned over one of the ends24/26of the proximal and distal guidewire sections14/16. The distal end24of the proximal portion14and proximal end26of the distal portion16are then positioned adjacent one another in an overlapping12or an end-to-end13arrangement. The proximal and distal guidewire sections14/16and the connector tube18may be bonded, welded (e.g., resistance or laser welded), soldered, brazed, or otherwise connected by a suitable technique depending on the material selected for each component. Alternatively, the ends24/26and the connector tube18may be crimped together or may be sized to establish a friction fit therebetween. If a connector tube18is not used, the ends24/26may be bonded, welded (e.g., resistance or laser welded), soldered, brazed, or otherwise connected, using a connector material19. Connector material19may be the same as or similar to the material of the connector18. In all cases, because the connection20may reside within a catheter lumen during use, it is preferred that a permanent connection (as opposed to a releasable connection) be used.

It is to be appreciated that various welding processes may be utilized without deviating from the spirit and scope of the present invention. Examples of welding processes which may be suitable in some applications include LASER welding, resistance welding, TIG welding, microplasma welding, electron beam, and friction or inertia welding. LASER welding equipment which may be suitable in some applications is commercially available from Unitek Miyachi of Monrovia, Calif. and Rofin-Sinar Incorporated of Plymouth, Mich. Resistance welding equipment which may be suitable in some applications is commercially available from Palomar Products Incorporated of Carlsbad, Calif. and Polaris Electronics of Olathe, Kans. TIG welding equipment which may be suitable in some applications is commercially available from Weldlogic Incorporated of Newbury Park, Calif. Microplasma welding equipment which may be suitable in some applications is commercially available from Process Welding Systems Incorporated of Smyrna, Tenn.

Once connected, the connector tube18and the proximal and distal guidewire sections14/16are centerless ground to provide a smooth and uniform profile across the connection20, and to straighten out small misalignments between the proximal and distal guidewire sections14/16. Other portions of the guidewire10may be ground as well to provide the desired tapers and changes in diameter. For example, one or both of the proximal and distal guidewire sections14/16can be continuously tapered, can have a tapered section or a number or series of tapered sections of differing diameters, or can have a constant diameter. In some embodiments, the sections14/16are tapered or otherwise formed to have a geometry that decreases in cross sectional area toward the distal end thereof. If tapered, the sections14/16can include a uniform or a non-uniform transition of the sections, depending on the transition characteristics desired. For example, one or both of the sections14/16may be linearly tapered, tapered in a curvilinear fashion, or tapered in a step-wise fashion. The angle of any such tapers can vary, depending upon the desired flexibility characteristics. The length of the taper may be selected to obtain a more (longer length) or less (shorter length) gradual transition in stiffness. Once finally ground, in some embodiments, a flexible coil tip and/or a polymer jacket tip (optionally covering connection20) or combination thereof, and other such structure, such as radiopaque markers, safety and/or shaping ribbons (coiled or uncoiled), and the like, may be placed on the guidewire10. Additionally, in some embodiments, a coating, for example a lubricious (e.g., hydrophylic) or other type of coating may be applied to all or portions of the guidewire. Different coatings can be applied to different sections of the guidewire. Some examples of such coatings and materials and methods used to create such coatings can be found in U.S. Pat. Nos. 6,139,510 and 5,772,609, which are incorporated herein by reference.

The centerless grinding technique may utilize an indexing system employing sensors (e.g., optical/reflective, magnetic) to avoid excessive grinding of the connection20. In some embodiments, the presence of dissimilar materials in the construction can influence the grinding technique and tooling used to accomplish uniform material removal, create smooth transitions, and successfully bridge across adjacent components. In addition, the centerless grinding technique may utilize a CBN or diamond abrasive grinding wheel that is well shaped and dressed to avoid grabbing the connector20during the grinding process.

Refer now toFIG. 7, which shows a cross sectional view of a portion of a guidewire110including a connection120similar to the connection20shown in the embodiment ofFIG. 1. The connection120utilizes an overlapping tapered joint112and a tubular connector118joining a proximal guidewire section114and a distal guidewire section116. The proximal/distal guidewire sections114/116, the connection120, the tapered joint112, and the tubular connector118shown in the embodiment ofFIG. 7can include the same general construction, structure, materials, and methods of construction as discussed above with regard to like components in the embodiments ofFIGS. 1–6C.

The embodiment ofFIG. 7also shows one example of a distal tip portion130of the guidewire110disposed at the distal end portion134of the distal guidewire section116. The distal end portion134includes two tapered regions142and146, and two constant diameter regions150and154such that the end portion134has a geometry that decreases in cross sectional area toward the distal end thereof. In some embodiments, these tapers142/146and constant diameter regions150/154are adapted and configured to obtain a transition in stiffness, and provide a desired flexibility characteristic.

A wire or ribbon158is attached adjacent the distal end160of the distal end portion134, and extends distally of the distal end portion134. In some embodiments, the wire or ribbon158can be a fabricated or formed wire structure, for example a coiled wires, as will be seen in embodiments discussed in more detail below. In the embodiment shown, the ribbon158is a generally straight wire that overlaps with and is attached to the constant diameter region154at attachment point164. In some embodiments, the ribbon158overlaps with the constant diameter section154by a length in the range of about 0.05 to 1.0 inch, but in other embodiments, the length of the overlap can be greater or less.

The ribbon158can be made of any suitable material and sized appropriately to give the desired characteristics, such as strength and flexibility characteristics. Some examples of suitable materials include metals, metal alloys, polymers, and the like. In some embodiments, the ribbon158may be formed of a metal or metal alloy such as stainless steel, nickel-chromium alloy, nickel-chromium-iron alloy, cobalt alloy, a nickel-titanium alloy, such as a straightened super elastic or linear elastic alloy (e.g., nickel-titanium) wire. The ribbon158can be attached using any suitable attachment technique. Some examples of attachment techniques include soldering, brazing, welding, adhesive bonding, crimping, or the like. In some embodiments, the ribbon or wire158can function as a shaping structure or a safety structure.

An outer sleeve168is disposed about the distal end portion134of the distal guidewire section116. In the embodiment shown, the sleeve168extends from the proximal tapered region142to beyond the distal most portion of the ribbon158, and forms a rounded tip portion169. In other embodiments, the sleeve158can extend further in a proximal direction, and in some cases can extend over the connection120, or over the proximal guidewire section114. In yet other embodiments, the sleeve168can begin at a point distal of the tapered region142.

Suitable material for use as the outer sleeve168include any material that would give the desired strength, flexibility or other desired characteristics. Some suitable materials include polymers, and like material. Examples of suitable polymer material include any of a broad variety of polymers generally known for use as guidewire polymer sleeves. The use of a polymer for outer sleeve168can serve several functions. The use of a polymer sleeve can improve the flexibility properties of the distal portion134. Choice of polymers for the sleeve168will vary the flexibility. For example, polymers with a low durometer or hardness will make a very flexible or floppy tip. Conversely, polymers with a high durometer will make a tip which is stiffer. The use of polymers for the sleeve can also provide a more atraumatic tip for the guide wire. An atraumatic tip is better suited for passing through fragile body passages. Finally, a polymer can act as a binder for radiopaque materials, as discussed in more detail below.

In some embodiments, the polymer material used is a thermoplastic polymer material. Some examples of some suitable materials include polyurethane, elastomeric polyamides, block polyamide/ethers (such as Pebax), silicones, and co-polymers. The sleeve may be a single polymer, multiple layers, or a blend of polymers. By employing careful selection of materials and processing techniques, thermoplastic, solvent soluble, and thermosetting variants of these materials can be employed to achieve the desired results.

The sleeve168can be disposed around and attached to the guidewire110using any suitable technique for the particular material used. In some embodiments, the sleeve168is attached by heating a sleeve of polymer material to a temperature until it is refonned around the distal guidewire section116and the ribbon158. In some other embodiments, the sleeve168can be attached using heat shrinking techniques. The sleeve168may be finished, for example, by a centerless grinding or other method, to provide the desired diameter and to provide a smooth outer surface.

In some embodiments, the sleeve168, or portions thereof, can include, or be doped with, radiopaque material to make the sleeve168, or portions thereof, more visible when using certain imaging techniques, for example, fluoroscopy techniques. Any suitable radiopaque material known in the art can be used. Some examples include precious metals, tungsten, barium subcarbonate powder, and the like, and mixtures thereof. In some embodiments, the sleeve168can include different sections having different amounts of loading with radiopaque material. For example, inFIG. 7, the sleeve168includes a distal section170, and a proximal section172, wherein the distal section170has a higher level of loading with radiopaque material than the proximal section172. In some embodiments, it is also contemplated that a separate radiopaque member or a series of radiopaque members, such as radiopaque coils, bands, tubes, or other such structures could be attached to the guidewire110, or incorporated into the core wire by plating, drawing, forging, or ion implantation techniques.

Additionally, in some embodiments, a coating, for example a lubricious (e.g., hydrophylic) or other type of coating may be applied over portions or all of the sleeve, or other portions of the guidewire110. Hydrophobic coatings such as fluoropolymers provide a dry lubricity which improves guide wire handling and device exchanges. Lubricious coatings improve steerability and improve lesion crossing capability. Suitable lubricious polymers are well known in the art and may include hydrophilic polymers such as polyarylene oxides, polyvinylpyrolidones, polyvinylalcohols, hydroxy alkyl cellulosics, algins, saccharides, caprolactones, and the like, and mixtures and combinations thereof. Hydrophilic polymers may be blended among themselves or with formulated amounts of water insoluble compounds (including some polymers) to yield coatings with suitable lubricity, bonding, and solubility. Some other examples of such coatings and materials and methods used to create such coatings can be found in U.S. Pat. Nos. 6,139,510 and 5,772,609, which are incorporated herein by reference. In some embodiments, the more distal portion of the guidewire is coated with a hydrophilic polymer as discussed above, and the more proximal portions is coated with a fluoropolymer, such as polytetrafluroethylene (PTFE).

It will be understood by those of skill in the art and others that a broad variety of materials, dimensions, and structures can be used to construct suitable embodiments, depending upon the desired characteristics. The following examples of some dimensions for the distal construction are included by way of example only, and are not intended to be limiting. In some specific embodiments, the guidewire has the general structure set fourth inFIG. 7, and the distal guidewire section116has a length in the range of about 10 to 20 inches. The main portion of the distal guidewire section116has an outer diameter in the range of 0.013 to about 0.0145 inches, and the two constant diameter regions150and154have an outer diameter in the range of about 0.0094 to about 0.0097 and in the range of 0.001 to about 0.0014 respectively. The two constant diameter regions150and154have a length in the range of about 4 to about 15 inches and in the range of about 0.5 to about 4 inches respectively. The two tapered regions142and146have lengths in the range of about 0.5 to about 2 inches and in the range of about 0.5 to about 2 inches, respectively. The polymer sleeve168has an outer diameter sized to match the outer diameter of the main portion of the distal guidewire section116, for example in the range of about 0.013 to about 0.0145 inches. The polymer sleeve distal section170, is loaded with a radiapaque material, and has a length in the range of about 1 to about 3 inches. The ribbon158has a length in the range of about 0.8 to about 2 inches, and in some embodiments can extend about 0.2 to about 1 inch distally of the core.

FIG. 8shows a guidewire110very similar to that shown inFIG. 7, wherein like reference numerals indicate similar structure as discussed above. The proximal/distal guidewire sections114/116, the connection120, the tapered joint112, and the tubular connector118shown in the embodiment ofFIG. 8can also include the same general construction, structure, materials, and methods of construction as discussed above with regard to like components in the embodiments ofFIGS. 1–7.

The distal tip portion130of the guidewire110ofFIG. 8is also very similar to that shown inFIG. 7, wherein like reference numerals indicate similar structure. In the embodiment shown inFIG. 8, however, the ribbon158extends further in a proximal direction to overlap with the tapered region146, and is attached at two attachment points164and165.

Refer now toFIG. 9, which shows a cross sectional view of a portion of another embodiment of a guidewire210including a connection220similar to that shown in the embodiments ofFIGS. 7 and 8. The proximal/distal guidewire sections214/216, the connection220, the tapered joint212, and the tubular connector218shown in the embodiment ofFIG. 9can include the same general construction, structure, materials, and methods of construction as discussed above with regard to like components in the embodiments ofFIGS. 1–8.

The embodiment ofFIG. 9shows another example of a distal tip portion230of the guidewire210disposed at the distal end portion234of the distal guidewire section216. Like the embodiment ofFIG. 7, the distal end portion234includes two tapered regions242. and246, and two constant diameter regions250and254such that the end portion234has a geometry that decreases in cross sectional area toward the distal end thereof. Additionally, the distal tip portion230also includes a wire or ribbon258that is attached adjacent the distal end260of the distal end portion234at attachment point264in a similar manner as taught above in the embodiment ofFIG. 7.

InFIG. 9, however, the distal tip portion230includes a combination of a sleeve268and a coil280disposed about the distal end portion234of the distal guidewire section216. The sleeve268extends from the proximal tapered region242to a point proximal of the distal end of the guidewire section216. In the embodiment shown, the sleeve268extends from the tapered region242to about midway through the tapered portion246. In other embodiments, the sleeve268can extend further in a proximal direction, and in some cases can extend over the connection220, or over the proximal guidewire section214. In yet other embodiments, the sleeve268can begin at a point distal of the tapered region242.

The sleeve268can be made of and include the same materials, structure, radiopaque loading, and coatings, and be made in accordance with the same methods as discussed above with regard to the embodiments shown inFIGS. 1–8. In the embodiment shown, an adhesive material or potting compound279is disposed at the distal end265of the sleeve268about the distal guidewire section216. However, in other embodiments, the adhesive material or potting compound279is not used.

The coil280extends from the adhesive material279adjacent the distal end265of the sleeve268to beyond the distal most portion of the ribbon258. The coil280is attached to the distal guidewire section216at its proximal end281at attachment point283using any suitable attachment technique, for example soldering, brazing, welding, adhesive bonding, crimping, or the like. The distal end285of the coil280is attached to the ribbon258via a rounded tip portion269. The rounded tip portion269can be made of any suitable material, for example a solder tip, a polymer tip, and the like.

The coil280may be made of a variety of materials including metals, metal alloys, polymers, and the like. Some examples of material for use in the coil include stainless steel, nickel-chromium alloy, nickel-chromium-iron alloy, cobalt alloy, or other suitable materials. Some additional examples of suitable material include straightened super elastic or linear elastic alloy (e.g., nickel-titanium) wire, or alternatively, a polymer material, such as a high performance polymer. In some embodiments, the coil280can be made of a radiopaque materials such as gold, platinum, tungsten, or the like, or alloys thereof. The coil280may be formed of round or flat ribbon ranging in dimensions to achieve the desired flexibility. In some embodiments, the coil280may be a round ribbon in the range of about 0.001–0.015 inches in diameter, and can have a length in the range of about 2 to about 4 inches.

The coil280is wrapped in a helical fashion by conventional winding techniques. The pitch of adjacent turns of coil280may be tightly wrapped so that each turn touches the succeeding turn or the pitch may be set such that coil280is wrapped in an open fashion. In the embodiment shown, the coil280is wrapped such that the coil280has an open wrap at its proximal end281, and includes a tightly wrapped portion adjacent the tip269.

Additionally, in some embodiments, a coating, for example a lubricious (e.g., hydrophylic) or other type of coating similar to that discussed above may be applied over portions or all of the sleeve268and coil280, or other portions of the guidewire210.

It will be understood by those of skill in the art and others that a broad variety of materials, dimensions, and structures can be used to construct suitable embodiments, depending upon the desired characteristics. The examples of some dimensions for the distal construction included with reference toFIG. 7are also suitable for the embodiment shown inFIG. 9.

FIG. 10shows a guidewire210very similar to that shown inFIG. 9, wherein like reference numerals indicate similar structure. The proximal/distal guidewire sections214/216, the connection220, the tapered joint212, and the tubular connector218shown in the embodiment ofFIG. 10can also include the same general construction, structure, materials, and methods of construction as discussed above with regard to like components in the embodiments ofFIGS. 1–9.

The distal tip portion230of the guidewire210ofFIG. 10is also very similar to that shown inFIG. 9, wherein like reference numerals indicate similar structure. In the embodiment shown inFIG. 10, however, the ribbon258extends further in a proximal direction to overlap with the tapered region246, and is attached at two attachment points264and283.

Refer now toFIG. 11, which shows a cross sectional view of a portion of another embodiment of a guidewire310including a connection320similar to that shown in the embodiments ofFIGS. 7–10. The proximal/distal guidewire sections314/316, the connection320, the tapered joint312, and the tubular connector318shown in the embodiment ofFIG. 11can include the same general construction, structure, materials, and methods of construction as discussed above with regard to like components in the embodiments ofFIGS. 1–10.

The embodiment ofFIG. 11shows another example of a distal tip portion330of the guidewire310disposed at the distal end portion334of the distal guidewire section316. Like the embodiment ofFIGS. 7–10, the distal end portion334includes two tapered regions342and346, and two constant diameter regions350and354such that the end portion334has a geometry that decreases in cross sectional area toward the distal end thereof Additionally, the distal tip portion330also includes a wire or ribbon358that is attached adjacent the distal end360of the distal end portion334at attachment point364in a similar manner as taught above in the embodiments ofFIGS. 7 and 9.

InFIG. 11, however, the distal tip portion330includes a dual coil tip construction having an outer coil380and an inner coil390disposed about the distal end portion334of the distal guidewire section316.

In the embodiment shown, the outer coil380extends about the distal guidewire section316from the tapered region342to beyond the distal most portion of the ribbon358. The outer coil380is attached to the distal guidewire section316at its proximal end381at attachment point383using any suitable attachment technique, for example soldering, brazing, welding, adhesive bonding, crimping, or the like. The distal end383of the coil380is attached to the ribbon358via a rounded tip portion369. The rounded tip portion369can be made of any suitable material, for example a solder tip, a polymer tip, and the like. The outer coil380can be made of the same materials, and have the same general construction and pitch spacing as the coil280discussed above in the embodiments ofFIGS. 9 and 10. In some embodiments, the outer coil280can extend distally beyond attachment point393for a length in the range of about 2 to about 4 centimeters.

In the embodiment shown, the inner coil390is disposed about the distal guidewire section316from the tapered region346to a spacer element395adjacent the tip portion369. In other embodiments, however, the spacer element is not required. The coil390is attached to the distal guidewire section316at its proximal end391at attachment point393using any suitable attachment technique, for example soldering, brazing, welding, adhesive bonding, crimping, or the like. The distal end397of the coil390is attached to the spacer element395. The spacer element395is disposed about the ribbon358, and can be made of any suitable material, for example metal, metal alloy, or a polymer, or the like. In some embodiments, the spacer is made of a polymer such as polytetrafluroethylene (PTFE).

The inner coil390can be made of the same materials, and have the same general construction and pitch spacing as discussed above with regard to the coil280in the embodiments ofFIGS. 9 and 10. In some embodiments, the inner coil390is made of a radiopaque wire having a diameter less than that of the wire used to make the outer coil380.

It will be understood by those of skill in the art and others that a broad variety of materials, dimensions, and structures can be used to construct suitable embodiments, depending upon the desired characteristics. The examples of some dimensions for the distal construction included with reference toFIG. 7are also suitable for the embodiment shown inFIGS. 9 and 11.

FIG. 12shows a guidewire310very similar to that shown inFIG. 11, wherein like reference numerals indicate similar structure. The proximal/distal guidewire sections314/316, the connection320, the tapered joint312, and the tubular connector318shown in the embodiment ofFIG. 12can also include the same general construction, structure, materials, and methods of construction as discussed above with regard to like components in the embodiments ofFIGS. 1–11.

The distal tip portion330of the guidewire310ofFIG. 12is also very similar to that shown inFIG. 11, wherein like reference numerals indicate similar structure. In the embodiment shown inFIG. 12, however, the ribbon358extends further in a proximal direction to overlap with the tapered region346, and is attached at two attachment points364and393.

Refer now toFIGS. 13–21, which show a series of alternative tip designs for use in guidewires which include a coiled or helically shaped portion of wire or ribbon for use as a safety and/or shaping structure. Such tip designs using a coiled or helically shaped safety or shaping structure can be used in a broad variety of guidewire structures. For example, these tip designs can be used in combination with other structure disclosed herein, such as the connector structures discussed above, or can be used in other guidewire constructions, for example guidewires that do not include such connector structures.

Refer now toFIG. 13, which shows one embodiment of a guidewire410having a coiled safety and/or shaping structure458. The guidewire410includes a core member413having a distal portion416. The core member413, and the distal portion416thereof, can include structure as disclosed above for portions of a guidewire, or can include other structure generally known in the art for use in guidewires. Additionally, the core member413, and the distal portion416thereof, can be made using any of the suitable materials discussed above for use in making guidewire members or sections, or can include other materials generally known in the art for use in guidewires. In the embodiment shown, the distal portion416of the core member413is a solid wire that has a tip portion434including three constant diameter portions450,452and454, and two tapered portions442and446.

The coiled safety and/or shaping structure458, for example a coiled ribbon, a coiled wire, or other such coiled structure, is disposed about a portion of the core wire413. In the embodiment shown, the coiled structure458is a coiled ribbon that overlaps with or surrounds a portion of the distal most tapered portion446and the distal most constant diameter portion454, and then extends distally from the distal end460of the core wire413.

The coil458can be made of any suitable material and sized appropriately to give the desired characteristics, such as strength and flexibility characteristics. In some embodiments, the attachment of the coil458to the core wire413can also influence the characteristics of the portion of the core wire413overlapped by the coil458.

Some examples of material for use in the coil458include stainless steel, nickel-chromium alloy, nickel-chromium-iron alloy, cobalt alloy, nickel-titanium alloy, or other suitable materials. Some additional examples of suitable material include straightened super elastic or linear elastic alloy (e.g., nickel-titanium), or alternatively, a polymer material, such as a high performance polymer. In some embodiments, the coil458can be made of a radiopaque materials such as gold, platinum, tungsten, or the like, or alloys thereof. The coil458may be formed of round or flat ribbon ranging in dimensions to achieve the desired flexibility. In some embodiments, the coil458may be a round wire in the range of about 0.001–0.015 inches in diameter. In some other embodiments, the coil can be made of a flat or rectangular shaped ribbon having a width in the range of about 0.002 to 0.02 inches and a thickness in the range of about 0.0005 to about 0.02 inches.

The coil458can be attached to the core wire413using any suitable attachment technique. Some examples of attachment techniques include soldering, brazing, welding, adhesive bonding, crimping, or the like. In the embodiment shown, the coil458is attached at two attachment points464and465.

The coil458is wrapped in a helical fashion by conventional winding techniques. The pitch of adjacent turns of coil458may be tightly wrapped so that each turn touches the succeeding turn or the pitch may be set such that coil458is wrapped in an open fashion. In some embodiments, the coil can have a pitch of up to about 0.4 inches, in some embodiments a pitch of up to about 0.08 inches, and in some embodiments, a pitch in the range of about 0.01 to about 0.08 inches. The pitch can be constant throughout the length of the coil458, or can vary, depending upon the desired characteristics, for example flexibility. In some embodiments, the pitch of the coil458portion that overlaps with the core wire413is smaller, while the pitch of the coil portion that does not overlap with the core wire413is larger. For example, in some embodiments, the pitch of the coil portion that overlaps with the core wire413is in the range of 0.01 to 0.08 inches, for example 0.04 inches, while the pitch of the coil portion that does not overlap with the core wire413is up to about 0.08 inches. These changes in coil pitch can be achieved during the initial winding of the wire, or can be achieved by manipulating the coil after winding or after attachment to the guidewire. For example, in some embodiments, after attachment of the coil458to the guidewire, a larger pitch can be achieved on the distal portion of the coil by simply pulling the coil.

The diameter of the coil458is preferably sized to fit around and mate with the distal portion of the core wire413, and to give the desired characteristics. The diameter of the coil458can be constant or tapered. In some embodiments, the coil458is tapered to mate with tapered sections of the core wire413. The diameter of the coil458can also include a taper beyond the distal end of the core wire413, as desired.

An outer sleeve468is disposed about the distal portion416of the guidewire410. In the embodiment shown, the sleeve468extends beyond the distal most portion of the coiled ribbon458, and forms a rounded tip portion469. The sleeve468can include structures, and be made with the materials and methods discussed above with regard to sleeve structures.

It will be understood by those of skill in the art and others that a broad variety of materials, dimensions, and structures can be used to construct suitable embodiments, depending upon the desired characteristics. The following examples are included by way of example only, and are not intended to be limiting. In some specific embodiments, the guidewire has the general structure set fourth inFIG. 13, wherein the core wire413is a distal portion of a core wire made of linear elastic nickel-titanium alloy, wherein the constant diameter portions450,452and454are about 0.0097 inches, 0.006 inches, and 0.003 inches in diameter, respectively. Additionally, the constant diameter portions452and454are about 1 inch and 0.5 inches in length, respectively. The tapered portions442and446are about 1 inch and 1.5 inches, respectively. The coil458is about 1.5 inches long, is made of flattened stainless steel wire having width and thickness dimensions of about 0.005 inches by about 0.001 inches. The coil458has a diameter that is tapered from about 0.0097 inches on its proximal end to about 0.003 inches on its distal end, and is attached to the core wire413at attachment points464and465using solder. The coil458overlaps the core wire413for about 1.1 inches, and extends distally of the core wire413for about 0.4 inches. The pitch of the coil portion that overlaps the core wire is about 0.04 inches and the pitch of the coil portion that extends distally of the core wire is about 0.08 inches. In some such embodiments, the portion of the guidewire where the coil458overlaps the core wire413for about 1.1 inches is plated, for example, with tin plating. The sleeve468is a polyurethane sleeve attached about the core wire413and coil458. A hydrophilic coating is then coated onto the sleeve468.

Refer now toFIG. 14, which shows a guidewire410having a tip construction similar to that shown inFIG. 13, wherein like reference numerals indicate similar structure. The core wire413in the embodiment ofFIG. 13, however, has a tip portion434including one constant diameter portion450, and one tapered portion442, and the coiled ribbon458is attached around a portion of the tapered portion442. The other aspects and components of the embodiment shown inFIG. 14can include the same general structure and materials as discussed above with regard toFIG. 13.

In some specific embodiments, the guidewire413has the general structure set fourth inFIG. 14, wherein the core wire413is a distal portion of a core wire made of linear elastic nickel-titanium alloy, wherein the constant diameter portion450is about 0.0097 inches in diameter, and the tapered portion442is about 3 inches long, ending at the distal end thereof at a diameter of about 0.003 inches. The coil458is about 1.5 inches long, is made of flattened stainless steel wire having width and thickness dimensions of about 0.005 inches by about 0.001 inches. The coil458has a diameter that is tapered from about 0.0097 inches on its proximal end to about 0.003 inches on its distal end, and is attached to the core wire413at attachment points464and465using solder. The coil458overlaps the core wire413for about 1.1 inches, and extends distally of the core wire413for about 0.4 inches. The pitch of the coil portion that overlaps the core wire is about 0.04 inches and the pitch of the coil portion that extends distally of the core wire is about 0.08 inches. In some such embodiments, the portion of the guidewire where the coil458overlaps the core wire413for about 1.1 inches is plated, for example, with tin plating. The sleeve468is a polyurethane sleeve attached about the core wire413and coil458. A hydrophilic coating is then coated onto the sleeve468.

Refer now toFIG. 15, which shows a guidewire410having a tip construction similar to that shown inFIG. 13, wherein like reference numerals indicate similar structure. The core wire413in the embodiment ofFIG. 15, however, has a tip portion434including two constant diameter portions450, and454, and one tapered portion442. The coil458is attached around the constant diameter portion454. InFIG. 15, the coil458is attached at two attachment points464and465about the constant diameter portion454, is not tapered, and does not include a substantial pitch change along the length of the coil458. The other aspects and components of the embodiment shown inFIG. 15can include the same general structure and materials as discussed above with regard toFIG. 13.

Refer now toFIG. 16, which shows a guidewire410having a tip construction similar to that shown inFIG. 15, wherein like reference numerals indicate similar structure. In the embodiment ofFIG. 16, however, the pitch of the coil458is lengthened distal to the attachment point464as compared to the pitch of the coil458proximal to the attachment point464. The other aspects and components of the embodiment shown inFIG. 16can include the same general structure and materials as discussed above with regard toFIG. 13.

Refer now toFIG. 17, which shows a guidewire410having a tip construction similar to that shown inFIG. 16, wherein like reference numerals indicate similar structure. In the embodiment ofFIG. 17, however, only attachment point464near the distal end of the core wire413is used. The other aspects and components of the embodiment shown inFIG. 17can include the same general structure and materials as discussed above with regard toFIG. 13.

Refer now toFIG. 18, which shows a guidewire410having a tip construction similar to that shown inFIG. 16, wherein like reference numerals indicate similar structure. In the embodiment ofFIG. 18, however, only the more proximal attachment point465is used. The other aspects and components of the embodiment shown inFIG. 18can include the same general structure and materials as discussed above with regard toFIG. 13.

Refer now toFIG. 19, which shows a guidewire410having a tip construction similar to that shown inFIG. 16, wherein like reference numerals indicate similar structure. In the embodiment ofFIG. 19, however, the safety and/or shaping structure458has a coiled portion490that is coiled around the constant diameter portion454, and then transforms into a non-coiled portion492that extends distally from the distal end of the core wire413. The other aspects and components of the embodiment shown inFIG. 18can include the same general structure and materials as discussed above with regard toFIG. 13.

Refer now toFIG. 20, which shows a guidewire410having a tip construction similar to that shown inFIG. 19, wherein like reference numerals indicate similar structure. In the embodiment ofFIG. 20, however, the safety and/or shaping structure458includes two separate portions—a generally straight portion492that overlaps with the constant diameter portion454and extends distally from the distal end of the core wire413, and a coiled portion490that is coiled around both the straight ribbon portion492and the constant diameter portion454to attach the straight portion492to the constant diameter portion454. The other aspects and components of the embodiment shown inFIG. 18can include the same general structure and materials as discussed above with regard toFIG. 13.

Refer now toFIG. 21, which is a partial cross sectional view of a guidewire410tip construction similar to that shown inFIG. 19, wherein like reference numerals indicate similar structure. Like the embodiment ofFIG. 19, the embodiment shown inFIG. 21includes a safety and/or shaping structure458that has a coiled portion490that is coiled around the constant diameter portion454, and then safety and/or shaping structure458transforms into a non-coiled portion492that extends distally from the distal end of the core wire413. However, inFIG. 21, the non-coiled portion492is twisted to form a helix shaped wire. The other aspects and components of the embodiment shown inFIG. 21can include the same general structure and materials as discussed above with regard toFIG. 13.

Refer now toFIG. 22, which is a partial cross sectional view of a guidewire410including a tip construction similar to the distal tip portion230of the guidewire210shown inFIGS. 9 and 10, wherein like reference numerals indicate similar structure. In the embodiment ofFIG. 22, however, the tip construction includes a coiled safety and/or shaping structure458rather than a non-coiled ribbon258as shown ofFIGS. 9 and 10. The coil is attached to the guidewire at two attachment points464and465, for example, through soldering. The other aspects and components of the embodiment shown inFIG. 21can include the same general structure and materials as discussed above with regard toFIGS. 9 and 10, and/or with regard toFIG. 13.

Refer now toFIG. 23, which is a partial cross sectional view of a guidewire410including a tip construction similar to the distal tip portion230of the guidewire210shown inFIGS. 11 and 12, wherein like reference numerals indicate similar structure. In the embodiment ofFIG. 23, however, the tip construction includes a coiled safety and/or shaping structure458rather than a non-coiled structure258as shown ofFIGS. 11 and 12. The coil is attached to the guidewire at two attachment points464and465, for example, through soldering. Additionally, the embodiment ofFIG. 21also does not include an inner coil390and a spacer395as shown inFIGS. 11 and 12. The other aspects and components of the embodiment shown inFIG. 21can include the same general structure and materials as discussed above with regard toFIGS. 11 and 12, and/or with regard toFIG. 13.

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 invention. For example, alternative structure can be used in connecting the proximal and distal sections of guidewires. Additionally, alternative tip constructions including a flexible coil tip, a polymer jacket tip, a tip including a coiled safety/shaping wire, or combination thereof, and other such structure may be placed on the guidewire. The invention's scope is, of course, defined in the language in which the appended claims are expressed.