Intravascular device with carrier tube engagement member

An intravascular device having an elongate shaft and a proximal hub assembly. The proximal hub assembly includes an interference fit member (IFM) which forms an interference fit with a carrier tube to reduce the tendency of the device to fall out of the carrier tube during handling and to provide for easy removal of the device when ready for use.

FIELD OF THE INVENTION

The present invention generally relates to medical devices and packaging methods therefor.

BACKGROUND OF THE INVENTION

Elongate intravascular devices such as balloon catheters and guide wires are often packaged in carrier tubes. A carrier tube provides a convenient way to package and handle an otherwise unwieldy intravascular device, but the intravascular device may have a tendency to fall out of the carrier tube. As such, there is an ongoing need to provide improved devices and packaging techniques to reduce this tendency.

SUMMARY OF THE INVENTION

To address this need, the present invention provides a number of alternative solutions. In one embodiment, for example, the present invention provides an intravascular device having an elongate shaft and a proximal hub assembly. The proximal hub assembly includes an interference fit member (IFM) which forms an interference fit with a carrier tube. The interference fit reduces the tendency of the device to fall out of the carrier tube during shipping and handling, but provides for easy removal of the device when it is ready for use.

DETAILED DESCRIPTION OF THE INVENTION

Refer now toFIG. 1which illustrates a partially cross-sectioned plan view of a package10and an intravascular device20disposed therein. The package10includes a package wall12defining an elongate package lumen14therein. The package lumen14may be sized to accommodate substantially the entire length of the intravascular device20therein. The package lumen14may have an open proximal end and an open or closed distal end.

By way of example, not limitation, the package10is shown to be a carrier tube10having a carrier tube lumen14defined by a carrier tube wall12. Carrier tube10may be formed utilizing conventional materials, dimensions and techniques. For example, the carrier tube10may be formed of an extruded polymer comprising a blend of 50% polyolefin copolymer available under the trade name SURLYN and 50% high density polyethylene, having an inside diameter ranging from 0.10 to 0.30 inches, a wall thickness ranging from 0.002 to 0.020 inches, and a length ranging from 12 to 72 inches. Other suitable polymers for the carrier tube10include thermoplastics such as fluoropolymers (PTFE, FEP, PFA, CTFE), nylons, phenylene oxides, polyesters, polyethylenes, polypropylene, polyurethanes, combinations thereof, blends thereof, etc.

Intravascular device20is removably disposed in the lumen14of the carrier tube10. Intravascular device20generically refers to a wide variety of elongate intravascular devices such as catheters and guide wires. For example, the intravascular device may comprise a balloon catheter, a guide catheter, a diagnostic catheter, a guide wire, a drug delivery catheter, an atherectomy catheter, a tubular sheath, a stent delivery catheter, etc.

For purposes of illustration only, intravascular device20is shown in the form of an intravascular balloon catheter20having an elongate shaft22, a distally mounted balloon24and a stent26disposed thereon. A proximal portion28of the elongate shaft2is connected to a hub assembly30.

Hub assembly30includes a hub portion32and a strain relief34. The proximal portion28of the elongate shaft22extends through the strain relief34and into the hub32. The hub assembly30may be adhesively or thermally bonded to the proximal shaft portion28. Alternatively, the proximal portion28of the elongate shaft22may be connected to the hub assembly by an insert molding technique. As a further alternative, the hub assembly32may be removably connected to the proximal shaft portion28utilizing a releasable compression fitting.

The hub32and the strain relief34may be a two-piece construction or a one-piece construction as shown. Examples of one-piece and two-piece constructions are described in U.S. Pat. No. 6,273,404 B1 to Holman et al, the entire disclosure of which is incorporated herein by reference. In one-piece constructions, the hub32and the strain relief34may be formed of the same material, such as polycarbonate. Other moldable polymeric material having sufficient impact resistance and chemical resistance may be utilized as well. In two-piece constructions, the hub32and the strain relief34may be formed of two different materials. For example, the hub may be formed of polycarbonate, and the strain relief may be formed of a relatively less rigid polymer such as polyurethane available under the trade name PELLETHANE.

The strain relief34reduces the tendency of the proximal shaft portion28to kink just distal of the hub32. Typically, the hub32is relatively stiff and rigid, whereas the shaft22/28is relatively flexible, which may create a stress concentration point therebetween, absent the strain relief34. Thus, the strain relief34provides a gradual transition in stiffness between the hub32and the proximal shaft portion28. In this particular embodiment, the strain relief34has a helical shape and a gradual reduction in profile, as described by Holman et al., to provide such a transition in stiffness.

In this particular embodiment, the hub32includes a single port fluid connector36for connection to an ancillary device such as an inflation device (not shown). The hub32may incorporate more than one connector36, or no connector at all, depending on the type of intravascular device20utilized. For example, an otherwise conventional guide wire may not require a fluid connector36, whereas an otherwise conventional over-the-wire (OTW) type balloon catheter may require a double port connector36.

Also in this particular embodiment, the hub assembly30includes a pair of wings38to facilitate easier handling and manipulation of the catheter20. The particular shape of the wings38may vary, depending on the manipulation requirements of the device20. In some instances, wings38may not be necessary or desirable.

The hub assembly30includes an interference fit member (IFM)40connected to a distal portion of the hub32, proximal of the strain relief34. The IFM40may be connected to any portion of the hub assembly30, or to any portion of the proximal shaft28. The IFM40may form an interference fit with any portion the carrier tube10, such as the inside surface of the carrier tube wall12as shown inFIG. 1.

As seen inFIG. 1, the carrier tube wall12and/or the IFM40has sufficient compressibility to deform and thereby permit the IFM40to enter into the carrier tube lumen14despite the nominal difference in size. The interference fit between the IFM40and the carrier tube10establishes sufficient friction to resist gravitational and handling forces which may otherwise cause the device20to fall out of the carrier tube10. The friction created by the interference fit may also be sufficiently small to permit easy removal of the device20from the carrier tube10as shown inFIG. 2.

The IFM40may be sized and shaped to be fully or partially disposed inside the carrier tube lumen14. By fully extending the IFM40into the carrier tube lumen14a distance from the proximal end of the carrier tube10, the IFM40is less likely to be accidentally dislodged by rough handling or the like. To this end, the IFM40may establish a contact surface area with the inside surface of the carrier tube wall14that is distal of the proximal end of the carrier tube10.

In the embodiment illustrated inFIGS. 1 and 2, the IFM40comprises a ring having middle portion42and end portions44. End portions44may be tapered and may have a diameter or profile that is less than the diameter or profile of the middle portion42. The middle portion42may have a diameter or profile that is greater than the inside diameter or inside profile of the carrier tube10adjacent the proximal end thereof. For example, the middle portion42may have a diameter or profile that is 0.0005 to 0.010 inches greater than the inside diameter or inside profile of the carrier tube10. Also by way of example, if the inside diameter of the carrier tube10is approximately 0.17 to 0.18 inches, the middle portion42may have a diameter of approximately 0.181 to 0.187 inches. In some embodiments, as shown inFIG. 2A. the IFM40can comprise more than one ring.

The remainingFIGS. 3–15described herein illustrate variations of the hub assembly30and IFM40. Except as described and evident from the drawings, the principles of design, function, use and manufacture may be the same as described previously. To this end, similar elements may be numbered the same or have the same last two digits.

Refer now toFIG. 3which illustrates a partially cross-sectioned exploded view of the proximal portion of the carrier tube10and an alternative catheter120. The catheter120includes a hub assembly130having a hub132and a snap-fit strain relief134. The snap-fit strain relief134may be connected to the hub132utilizing a mechanical lock150. Mechanical lock150includes mating parts152/154which permit the strain relief134to be easily snap-fit onto the hub132to establish a rigid connection therebetween, as described by Holman et al.

An IFM140is disposed on the strain relief134. The IFM140may comprise a circular ring as shown inFIG. 2or a plurality of protrusions distributed about the circumference of the strain relief134as illustrated inFIG. 4. The IFM140includes a middle portion142and tapered end portions144. Middle portion142establishes an interference fit with the inside surface of the carrier tube wall12.

Refer now toFIG. 5which illustrates a partially cross-sectioned exploded view of the proximal portion of the carrier tube10and an alternative catheter220disposed therein. The catheter220includes a hub assembly230having a hub232and a snap-fit strain relief234. The strain relief234may be connected to the hub232by a mechanical lock250as described by Holman et al. Hub232also includes a plurality of grip protrusions233disposed about the circumference of the hub232proximal of the strain relief234and distal of the wings238as best seen inFIG. 6. Grip protrusions233enhance the ability of the physician to grip the hub assembly230to manipulate the catheter220.

An IFM240is disposed on the strain relief234. The IFM240may comprise a circular ring as illustrated inFIG. 2or a plurality of protrusions distributed about the circumference of the strain relief234as shown inFIG. 6. The IFM240includes a middle portion242and tapered end portions244. The middle portion242forms an interference fit with the inside surface of the carrier tube wall12.

Refer now toFIG. 7which illustrates a plan view of a proximal portion of an alternative catheter320. Catheter320includes a hub assembly330having a hub332and an integral strain relief334. An IFM340is disposed on the hub332just proximal of the strain relief334. The IFM340comprises a thin ring having a middle portion342and a tapered proximal portion344. The middle portion342engages the inside surface of the carrier tube wall12(not shown) to form an interference fit therebetween.

Refer now toFIG. 8which illustrates a plan view of a proximal portion of an alternative catheter420. The catheter420includes a hub assembly430having a hub432and a snap-fit strain relief434. A mechanical lock450having mating members452/454mechanically connects the hub432to the strain relief434as described by Holman et al. An IFM440is disposed on a proximal portion of the strain relief434. The IFM440comprises a circular ring having a middle portion442and a proximal tapered portion444. The middle portion442of the IFM440engages the inside surface of the carrier tube wall12(not shown) to form an interference fit therebetween.

Refer now toFIG. 9which illustrates an exploded view of the proximal portion of the carrier tube10and an alternative catheter520disposed therein. Catheter520includes a hub assembly530having a hub532and a snap-fit strain relief534. The hub532may be connected to the strain relief534by a mechanical connection550having mating elements552/554as described by Holman et al.

An IFM540is connected to the strain relief534distal of the mechanical connection550. The IFM540includes a pair of opposing flexure arms542each having one or more teeth544. Flexure arms542may bias the teeth544against the outside surface of the carrier tube wall12. The teeth544form an interference fit with the outside surface of the carrier tube wall12.

Refer now toFIG. 10which illustrates a plan view of the proximal portion of the carrier tube10and an alternative catheter620disposed therein. The catheter620includes a hub assembly630having a hub632and an integral strain relief634. An IFM640is disposed on the hub632proximal of the strain relief634. The IFM640includes a pair of opposing flexure arms642, each having one or more teeth644. Flexure arms642bias the teeth644against the outside surface of the carrier tube wall12to establish an interference fit therebetween.

Refer now toFIGS. 11–15which illustrate isometric views of the proximal portion of the carrier tube10and alternative designs of a catheter720having a double port hub assembly730. The double port hub assembly730is particularly suitable for over the wire (OTW) type balloon catheters. The hub assembly730includes a pair of port connectors736.

In each of the embodiments illustrated inFIGS. 11–15, the hub assembly730includes a hub portion732and a strain relief portion734. Also in each of the embodiments illustrated inFIGS. 11–15, an IFM740in the form of a plurality of protrusions is disposed on a portion of the hub assembly730. Each of the protrusions740includes a middle portion742and tapered end portions744. The middle portion742forms an interference fit with the inside surface of the carrier tube wall12.

In the embodiments illustrated inFIGS. 11 and 12, the hub732and the strain relief734are integrally formed as described by Holman et al. In the embodiments illustrated inFIGS. 13–15, the hub732and the strain relief734comprise a two-piece construction that may be snap-fit together using a mechanical connection750including mating members752and754as described by Holman et al.

In the embodiments described inFIGS. 11,12and15, the IFM740is disposed on a distal portion of the hub732. In the embodiments illustrated inFIGS. 13 and 14, the IFM740is disposed on the strain relief734.

In the embodiments illustrated inFIGS. 11 and 13, the IFM740comprises four protrusions distributed about the circumference of hub assembly730spaced apart by approximately 90 degrees. In the embodiments illustrated inFIGS. 12,14and15, the IFM740comprises six protrusions spaced approximately 60 degrees apart about the circumference of the hub assembly730.