THREADER FOR ANGIOPLASTY SYSTEM

TECHNICAL FIELD This invention relates generally to angioplasty and particularly to a method and device to more easy facilitate stent delivery, by means of a threader device, comprising a body with; a distal end portion having a first frusta conical inlet portion, a proximal end portion having a second inlet portion, preferably also in the form of a frusta conical inlet, a catheter positioning portion and, a channel portion joining the distal end portion with the proximal end portion. More specifically the present invention pertains to an improved mechanism/method for back-loading the proximal end of a guidewire to a second balloon/stent segment, typically while the surgical procedure is underway.

PRIOR ART

When performing surgery to position a stent within a capillary in the human body, a guidewire is first introduced into the body and its distal end positioned at the place where the stent is to be fixed. Thereafter a catheter comprising the stent is threaded on top of the proximal end of the guidewire, to accurately position the stent by means of following along the pre-positioned guidewire. As is well known the equipment, i.e. the catheter and the guidewire are expansive. As a consequence it is important for the staff of surgery to handle the equipment in a manner avoiding risk of damages. The threading of the catheter onto the guidewire is a handling sequent which involves risk of damages, since if the practitioner is unfortunate when trying to thread the catheter onto the guidewire they may interact in a manner to cause tip damages to the distal end of the catheter.

From US 5,078,699 there is known a threader device intended to assist in threading a catheter with a stent onto a guidewire. However, this known threader device is disadvantageous in several aspects. Firstly it is relatively complicated to handle due to the need of a pinching action of the threader device at the same time as a catheter has to be elaborated with. Secondly it is known a threader device as a relatively complicated to produce and therefore relatively costly. Also US 6,190,333 shows a threader device that is relatively costly and also disadvantageous in other aspects.

It is extremely important, and critical to the overall performance, that the proximal end of a guidewire be quickly and securely connected to a balloon/stent segment or a catheter and stent combination to facilitate insertion of a second balloon and/or stent into the patient.

SUMMARY OF THE INVENTION

Thanks to the invention there is provided a threader device easy to handle at the same time as it presents a design that may take the advantage of cost-efficient production methods, in accordance with the appending claims. A specific advantage is that the invention may allow for having the threader device to be disposable, which in turn may provide many advantages, e.g. to allow for having the threader device pre-mounted on a catheter, such that it without any extra handling is correctly positioned and if in a sterile package, on top of that guaranteed sterile.

BRIEF DESCRIPTION OF THE FIGURES

In the following the invention will be described in more detail with reference to the enclosed drawings, wherein:

Fig. 1 shows a perspective view of a threader according to the invention, in assembled mode,

Fig. 2 shows a side view of the threader in Fig. 1,

Fig. 3 shows a perspective view of the threader according to Fig. 1 in disassembled mode,

Fig. 4 shows a second embodiment of a threader device according to the invention in a perspective view,

Fig. 5 is a cross-sectional view along lines V - V shown in Fig. 4,

Fig. 6 is a cross-sectional view along line VI - VI in Fig. 4,

Fig. 7 shows a third embodiment of a threader device according to the invention in a perspective view,

Fig. 8 shows the cross-sectional view indicated by VIII - VIII in Fig. 7,

Fig. 9 shows a fourth embodiment according to the invention in a perspective view, and

Fig. 10 shows a longitudinal cross-sectional view of the embodiment in Fig. 10.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Fig. 1 is a perspective view showing the novel "threader" 10, comprising a frusta- conical distal end portion 20 and a frusta-conical proximal end portion 30. The distal end 121 of threader 10 is shown ready to receive the proximal end 52 of a guidewire 50. It is to be understood that the distal end of guidewire 50, not shown in Fig. 1, remains inside the body of a patient undergoing treatment. It is necessary to quickly, reliably and securely insert the proximal end 52 of guidewire 50 into a catheter 60, which adjacent its distal end carries a balloon/stent segment 40. As is known per se balloon/stent segment 40 form a kind of annular package that is safely fitted onto the catheter 60. The catheter 60 has a lumen 65 (see Fig. 5), i.e. is hollow and has an inner diameter that slidably receives the proximal end 52 of guidewire 50. The distal end 63 of stent segment is preferably tapered to form a tapered distal tip 64.

The threader 10 shown in figs. 1-3, is made by two halves 110a and 110b, that can be snap-fitted together by means of protrusions 116, 117 fitting into corresponding cavities. The threader 10 includes a distal conical inner wall 120, proximal conical inner walls 130 and a body 115 between distal and proximal segments 120,130. Distal and proximal portions 20, 30 are frusta-conical in shape, each having a small end 122,132 connected to the body 115. The distal end 121 of distal portion 20 is the large end to facilitate insertion of the proximal end 52 of guidewire 50. Similarly, the proximal end 131 of proximal portion 30 is the large end to facilitate insertion of the distal end 64 of balloon/stent segment (or catheter) 30.

In this fashion, the large rather open ends 121 and 131 of distal and proximal segments 120 and 130 form relatively large openings into which the surgeon or surgical assistant may insert the proximal tip 52 of guidewire 50 and the tapered distal tip 64 of balloon/stent segment 40. In operation, the user simply inserts the tapered distal end 64 of the balloon/stent segment 40 into the proximal end 131 of proximal segment 130. The user then slides the proximal end 52 of guidewire 50 in the direction of the arrow 55, through distal segment 120, body 115 and through balloon/stent segment 40.

The threader is then separated from the guidewire 50 by simply unsnapping the two halves 110a and 110b from each other. The balloon/stent segment can then be immediately slid into position inside the patient's body. As is known per se once in the correct position the balloon is inflated to implement the stent in the desired position.

Fig. 2 is a side view of the threader 10 showing in phantom the internal passageways of the body 115 of threader 110. It is shown a distal end portion 20 having a first frusta conical section 120, a proximal end portion 30 having a second inlet portion also in the form of a frusta conical inlet section 130. Next to the second frusta conical inlet section 130, there is a first catheter positioning portion 80 that is cylindrical, having a diameter slightly larger than the balloon/stent segment 60. Next to the first catheter positioning portion 80 there is further frusta conical portion 90 converging to a more narrow diameter, to provide a stop for the end 64 of the balloon/stent segment 60. The small end of frusta conical portion 90 forms the transition to a channel portion 70 joining the distal end portion 20 with the proximal end portion 30, wherein the diameter of the channel 70 is sufficiently large to allow easy passage of the guidewire 50.

Fig. 3 shows a perspective view of the threader 10 according to Fig. 1 in disassembled mode, presenting that straight linear surfaces 119 preferably are used as interfaces between the two halves 110a, 110b.

In Figs. 4 - 6 it is shown a second embodiment according to the invention. In general the same basic principles are applied as described above. Accordingly there is a body 10 arranged with a distal, conical inlet portion 20, having a distal inlet end 221 in conjunction with a frusta conical inlet section 220, and a proximal distal, conical inlet portion 30 having a proximal inlet end 231 in conjunction with an, at least partly frusta conical inlet section 230. The proximal portion 30 in the transition zone between the conical portion and the intermediate channel 70 is arranged with catheter channel 80 and catheter positioning portion 90.

This embodiment substantially differs from the first embodiment in the arrangement of an additional support structure 211. This support structure 211 extends in a longitudinal direction of the threader device, i.e. parallel with the axis of the intermediate channel 70. Also this embodiment comprises a first body half 210a and a second body half 210b. The additional support 211 is integrated with the second body half 210b and extends a substantial distance away from the proximal, inlet end 231 , in a direction opposite the

location of the intermediate channel 70. The length of said additional support 211 is preferably within the range of 1-3 times the length of the upper body portion 210a. Substantially coaxial with the axis of the intermediate channel 70 there is provided a groove 212 within the additional support 211.

The purpose of the additional support body 211 is to provide a threader device 10 that is ergonomically optimal and also optimal from a handling viewpoint. Firstly the additional support body 211 provides extra support for the practitioner such that the threader device will be easily handled and to allow for comfortable and secure positioning of the threader device in the hand of the practitioner. Further, thanks to the coaxial groove 212 it will be very easy to position the catheter 60 properly into the threader device 10. Moreover, it makes the threader device more versatile, since the stent length may vary a lot (e.g. from 8-55 mm) and consequently this feature of the invention provides for the use of the same threader device for stents of different length, e.g. during transport, in a package including a pre mounted threader 10 on a catheter 60 it will provide support/protection for both long and short stents 40. Finally the additional body 211 permits an easy manual fixation of the catheter 60, by an ergonomic gripping of fingers around the additional support body 211 (once the threader is in correct position), simultaneously thereby fixing the catheter 60 in its correct position within the threader device 10.

As seen in Fig. 6 the two body halves 210a, 210b are integrated by means of a relatively narrow bridge device 215, which extends parallel with the axis of the channel 70. The function of said bridge 215 is to hold the body parts 210a, 210b together in a secure positioning thereof, to allow a safe and secure threading action. However after successful threading action is completed the threader device 10 has no longer any purpose to fulfill and therefore it may and should be dispensed with. By having the bridging portion 215 forming a relatively thin interconnecting member, produced in a breakable material this may be easily accomplished. As best seen in Fig. 4 each body half 210a, 210b is provided with transversally extending side sections 250, 251 that provide a kind of lever mechanism to separate the body halves 210a, 210b, by means of extending radially presenting a sharp angle α between them. In a preferred embodiment this is achieved by pressing the body sections 250, 251 towards each other, whereby a strain will occur in the bridging portion 215 that finally will break it apart, such that the threaded catheter 60 and guidewire 50 will be freed from the threader device 10.

In an alternative embodiment the bridging portion 215' may be produced in a somewhat more resistable material (see Fig. 6a) and/or thicker cross-section (see Fig. 6b), wherein instead of pressing the side sections 250, 251 against each other they are instead pressed in the opposite direction to allow a plastic deformation, at least partly, of the bridging portion 215 to open up the threader device 10. In Fig. 6 it is indicated that the bridging portion 215, 215' is positioned between the body halves 210a, 210b on the opposite side in relation to the extending side sections 250, 251. However, the skilled person realizes that the bridging portion 215 may in some appliances instead merely be positioned at the location where the extending side sections meet each other. In fact the latter mentioned positioning of the bridging portion 215 may in some cases be preferred, since it will make it easier to separate the body halves 210a, 210b from each other due to the fact that in such an embodiment a bending action will occur in the bridging portion 215, 215' whereas if the bridging portion 215, 215' is positioned along the opposite side a tensile force will act on the bridging portion. As a consequence it is mostly preferable to use a somewhat less rigid bridging portion 215, 215' if positioned on the opposite side in relation to the extending body sections 250, 251. For instance, if as indicated in the figures, the two body halves 210a, 210b are made by the same material, preferably by form molding in an appropriate polymer material the bridging portion may be provided with a perforation to facilitate the body halves to easily separate when pressing action is put onto the extending side sections 250, 251.

In yet another embodiment (not shown) a combination may be used, where bridging portions 215, 215' are applied along both sides, e.g. non-perforated along the side near the extending side sections 250, 251 and perforated along the other side.

Further as indicated in Fig. 6b a threader device according to the invention may also be made from two different body halves 210a, 210b, i.e. being produced in separate steps, preferably also by means of form molding, and in a later process step joined by means of the use of separate bridging portion 215', e.g. an appropriate metallic insert, which is integrated in an appropriate manner, e.g. by heating/melting and/or the use of an adhesive.

In Figs. 7 and 8 there is shown a further embodiment according to the invention. Basically this embodiment is rather similar to the embodiment shown in Figs. 4-6, i.e. comprising two body halves 310a, 310b, the lower half 31 Ob as a releasable interconnection portion 315, side sections 350, 351 and a support body 311 with a groove 312. A distinguishing feature is that in this embodiment there are provided two

further side sections 352, 353, extending in an opposite direction compared to the other side sections. Also these side sections do extend in a radial direction from the centre axis to form a sharp angle β between the protruding side sections 352, 353. As a consequence also the additional pair of side sections 352, 353 may be utilized to release the body halves 31 Oa, 31 Ob from each other.

As is shown in the cross-sectional view in Fig. 8, one of the side sections 350 protrudes further than the others. The reason is that said side section 350 is intended to be pressed by the thumb of the practitioner and thanks to its extra length provide extra leverage to break apart the body halves 310a, 310b. In the embodiment shown in cross-section (Fig. 8), which also indicates the use of a conical inlet section 330, there are two interconnecting bridge portions 315a, 315b between the body halves 310a, 310b. The skilled person realizes that also in this embodiment it may for some appliances be sufficient to merely have one such interconnecting bridge portion 315.

In Figs 9 and 10 there is shown a fourth embodiment according to the invention. The threader 10 comprises a lower body portion 410b and upper body portion 410a, wherein the lower body portion 410b has a larger circumferential than the upper body portion 410a. As a consequence the frusta-conical inlet portions 30, 20 are mainly arranged in the lower body portion 410b. As is indicated in the figures the longitudinal extension of the threader 10 is long enough to provide a comfortable and ergonomic support in the palm of the practitioner, presenting an embodiment where the distal and proximal ends 420, 430, of the threader per se 10, 20, 30, coincides with the whole length thereof, i.e. in this embodiment the support body forms an integrated part of the totality. In a preferred embodiment the total length of the catheter device is in a range of 40-150 mm, preferably within the range 50-120 mm, which is also applicable to the other embodiments described above. In this embodiment, the catheter passage 80 formed in the lower body 410b and enclosed by the upper body portion 410a extends a substantial distance of the threader device 10, due to the fact that the catheter positioning portion 90 is positioned nearby the distal end 20 which further leads to the passage 80 also forming a kind of supporting groove 412, as an integral feature of the passage 80. As a consequence the interconnecting channel 70 will in this embodiment be very short. The upper body portion 410a is preferably arranged as a planar layer joined to the lower portion of 410b by means of thin interconnecting bridges 415a, 415b in the transition zones. Thanks to this design there will be achieved an upper body portion 410a having a release mechanism in the form of easy to tear apart bridging portions 415a, 415b. A special advantage in this embodiment is that the conical side walls 421, 431 will provide

for easy access of a finger into either one of the ends 420, 430, e.g. into the distal end 20 to grab hold of the distal end 411 of the upper body portion 410a. By lifting that distal end 411 upwards the upper body portion 410a will easily come apart from the lower body portion 410b and subsequently free the catheter 60 threaded on top of the guide wire 50.

The foregoing description of the invention has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications and variations are possible in light of the above teaching. The embodiments were chosen and described to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best use the invention in various embodiments and with various modifications suited to the particular use contemplated.

Further it is foreseen that the threader device according to the invention may be integrated into a package containing the catheter 60 with the balloon/stent segment 40 and having them pre-positioned onto each other, whereby the practitioner immediately will be able to apply the catheter 60 onto the guidewire 50 upon opening of the package. In this regard it is also foreseen that the catheter device may, at least partly, form a part of the packaging device. As is evident a big variety of different materials may be used to produce the threader, i.e. not at all limited to polymers. Finally it should be mentioned that it is evident to the skilled person that the principle described above may also be applied in other fields of use, where similar need of quick and precise threading is of importance.