Source: http://www.freepatentsonline.com/y2010/0087906.html
Timestamp: 2020-01-23 19:32:23
Document Index: 112047929

Matched Legal Cases: ['art 40', 'art 40', 'art 40', 'art 40', 'art 40', 'art 40', 'art 40', 'art 40', 'art 40', 'art 40', 'art 40', 'art 40']

Catheter Device - Angiomed GmbH & Co. Medizintechnik AG
United States Patent Application 20100087906
A catheter device having a shaft that extends from a proximal end to a distal end to carry on its distal end a self-expanding implant for intraluminal advance on a guidewire and delivery of the implant to an implant site by proximal withdrawal of CD a sheath that lies radially outside the implant in the catheter, the catheter including a first shaft element to pull the sheath proximally and a second shaft element to push the implant distally to prevent the implant moving proximally with the sheath when the sheath is pulled proximally, wherein the second shaft element comprises a pusher-guider tube having a wall thickness with a plurality of discrete slits, the slits extending through the wall thickness of the pusher-guider tube.
Dorn, Jürgen (Neulussheim, DE)
Wuebbeling, Martin (Mannheim, DE)
11/917431
Angiomed GmbH & Co. Medizintechnik AG (Karlsruche, DE)
A61F2/966; A61M25/00; A61F2/95
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20090270996 MODULAR ORTHOPAEDIC COMPONENTS October, 2009 Meulink et al.
1. A catheter device having a shaft that extends from a proximal end to a distal end to carry on its distal end a self-expanding implant for intraluminal advance on a guidewire and delivery of the implant to an implant site by proximal withdrawal of a sheath that lies radially outside the implant in the catheter, the catheter including a first shaft element to pull the sheath proximally and a second shaft element to push the implant distally to prevent the implant moving proximally with the sheath when the sheath is pulled proximally, wherein the second shaft element comprises a pusher-guider tube having a wall thickness with a plurality of discrete slits, the slits extending through the wall thickness of the pusher-guider tube.
2. Catheter as claimed in claim 1, wherein the slits are arranged in a helical string on the outer surface and along the axial length of the pusher-guider tube.
3. Catheter as claimed in claim 2, wherein the helical arrangement of the slits forms more than one spiral along the length of the pusher-guider tube.
4. Catheter as claimed in claim 2, wherein there is at least as many discrete slits in the helical string as there are pitches in said helical string.
5. Catheter as claimed in claim 2, unslitted material between adjacent slits of the string being located on a line parallel to the long axis of the pusher-guider tube.
6. Catheter as claimed in claim 5, wherein the slits are arranged in two helical strings, each with its own line of unslitted material, and the respective lines associated with each of the two strings are 180° apart on the circumference of the pusher-guider tube.
7. Catheter as claimed in claim 6, wherein the pitch of the second helix is the same as that of the first helix.
8. Catheter as claimed in claim 1, wherein the second shaft element carries a stopper for abutting the implant, and wherein the arrangement of slits is confined to the portion of the pusher-guider tube distal of the stopper.
9. Catheter as claimed in claim 8, wherein the pusher-guider tube has been heat-treated, and the portion of the pusher-guider tube proximal of the stopper has a heat treatment history different from that of the portion distal of the stopper.
10. Catheter as claimed in claim 1, and loaded with an implant, wherein the pusher-guider tube extends distally beyond the distal end of the implant.
11. Catheter as claimed in claim 1, wherein at least an axial portion of the length of the pusher-guider tube is of stainless steel.
12. Catheter as claimed in claim 10, wherein the stainless steel tube has an elongation at fracture that is at least 40%.
13. Catheter as claimed in claim 1, wherein an axial portion of the length of the pusher-guider tube is made of a polymer.
14. Catheter as claimed in claim 1, including a self-expanding stent.
15. Catheter as claimed in claim 3, wherein there is at least as many discrete slits in the helical string as there are pitches in said helical string.
16. Catheter as claimed in claim 3, unslitted material between adjacent slits of the string being located on a line parallel to the long axis of the pusher-guider tube.
It is an object of the present invention to improve the deployment capabilities of the catheter-based implant delivery system to a target implant site in a human or animal body. These deployment capabilities are particularly important, when the implant is intraluminally advanced along a tortuous path through the system of body vessels. It is another object of the present invention to improve the capability of the delivery system to accurately release the implant at the implant site by proximal withdrawal of the sheath radially surrounding the implant.
These objects are solved by a feature combination of claim 1. Preferred, or optional features are the subject of the dependent claims.
The invention provides a catheter device in which a second shaft element for pushing the implant distally to prevent the implant from moving proximally with a sheath constraining the implant in a radially compressed delivery configuration inside the sheath of the catheter device comprises a pusher-guider tube having a wall thickness with a plurality of discrete slits that extend through the wall thickness of the pusher-guider tube. The slits render the pusher-guider tube more bendable than a tube without slits, but without prejudice to the ability of the pusher-guider tube to prevent the implant from moving proximally with the implant. The improved bendability has the effect that the steering capabilities of the catheter device are improved.
Furthermore, the slits are arranged such that axial bendability of the pusher-guider tube is improved, yet torqueability is maintained so that manoeuvrability of the catheter device by the medical practitioner is not compromised. Moreover, the improved bendability of the distal portion of the pusher-guider tube enables the pusher-guider tube to be made preferably of metal, thus adding to the metal modular structure of the catheter device.
Moreover, the catheter device of the present invention comprises a stopper for abutting the implant when proximally withdrawing the outer sheath. The arrangement of slits can be confined to the portion of the pusher-guider tube distal to the stopper. Thus, bendability of the portion distal to the stopper is increased so that the bendability capabilities of the catheter device distal to the stopper are determined by the bendability of the implant, that is to say the portion of the pusher-guider tube distal to the stopper has very little adverse effect on the overall bendability in the section of the catheter distal to the stopper. Where the portion of the pusher-guider tube distal to the stopper only serves the purpose of facilitating the insertion of the guidewire through the distal tip of the catheter, this portion needs no substantial mechanical strength for pushing, pulling or twisting any component of the catheter system.
In another embodiment of the present invention, the portion of the pusher-guider tube proximal of the stopper has been subjected to a heat treatment process, such as annealing, which is selected to yield a desired stiffness or bendability of the pusher-guider tube in the region proximal of the stopper, and the torqueability required and the ability to accommodate axially compressive when the stopper presses on the implant during proximal withdrawal of the sheath.
Furthermore, a shaft tube has more inherent resistance to elastic axial compression no other end-to-end shortening than a mere wire within the lumen of the tube. Thus, regardless how great are the tensile stresses imposed on the pull wire during the push-pull activity of stent release, there should be less unwanted proximal movement of the stopper from the intended site of stenting. The shaft tube may be of stainless steel or of a cobalt/chromium/nickel alloy sold under the trademark PHYNOX.
Furthermore, the sheath itself can also, be metal-reinforced (such as by an embedded metal braid) and so also with a high capacity to resist axial strain, increasing the precision with which the operator of the catheter device can control the progressive withdrawal of the sheath and release of the stent. Many doctors prefer to release a self-expanding stent in a step-wise movement. If the pulling system stretches, then a step-wise movement can have the consequence of a time-dependent response at the distal end of the system, and a relaxation of the pulling system between successive pulling steps, with consequent undesirable reverse distal movement of the sheath or else “lost movement” in the pulling system as it once again strains to take up the pull tension with successive step-wise pulls at the proximal end of the system.
One way of connecting the shaft tube to the stopper is by way of a pusher-guider tube which defines a guidewire lumen and carries the stopper at a location near the distal end of the pusher-guider tube, or at its distal end. The proximal end of the pusher-guider tube is arranged to one side of the distal end of the shaft tube and fixed relative to it, such as by welding or gluing. Conveniently, both the pusher-guider tube and the shaft tube are of metal such as stainless steel, simplifying the task of bonding together side-by-side the proximal end of the pusher tube and the distal end of the shaft tube, as by welding or brazing. Other means of joining these tube sections will be apparent to those readers skilled in the field, who will also appreciate that adhesive compositions are generally disfavoured, whenever failure of the adhesive bond results in failure of the device and risk to the patient, in use.
Examples in the state of the art of the use of a slit to increase flexibility of a metal tube are to be found in, for example, EP-A-1103281 and JP-A-2002 301161 Terumo. For a better understanding of the present invention, and to show more clearly how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings.
FIG. 11 is a longitudinal diametrical section through the proximal part of the shaft of the catheter-based delivery system
A particular embodiment of the present invention is described in FIG. 2A which is an improvement of the invention described in WO-A-2005/053574. It is obvious for the skilled person that parts of the disclosure of WO-A-2005/053574 also apply to what is shown in FIG. 2A.
With reference to FIG. 2A, proximal of the stent (not shown), and on the abluminal surface 24 of the sleeve 14, are swaged steel bands 26A, 26B, which are pressing the material of the sheath 14 enclosed by the bands 26A, 26B radially inwardly. Radially inside the sheath and longitudinally between the two bands 26a, 26b is a metal annulus 28. The metal annulus 28 is welded to a pull wire 32. The location at which the annulus 28 is welded to the pull wire 32 is indicated by reference numeral 28A. As can be seen in FIG. 2A, the diameter of the pull wire 32 is slightly reduced in a portion that lies radially inside the steel band 26B in order to accommodate the reduced inner diameter portion of the sheath 14. The outer diameter of the steel bands 26A, 26B is either equal or greater than the outer diameter of the sheath 14. The steel bands 26A, 26B are swaged onto the material of the sheath 14, but other methods of fixing the steel bands to the sheath are contemplated as well, such as gluing, crimping etc.
The bands 26a, 26b may not necessarily be made of stainless steel. Other materials include polymers, such as PHYNOX™, titanium, shape memory alloys, such as NITINOL™. The use of NITINOL™ may be advantageous in that the crimping down of the sheath to a reduced diameter at the position of the bands may occur upon exposing the catheter to a temperature change, such as by inserting it into the body of a human or an animal. The bands may also be made of radiopaque material so as to serve as marker bands. It is conceivable that the reduced inner diameter portion proximal of the annulus 28 may be provided by a tube heat-shrunk onto the luminal surface 24 of the sheath 14 at the location of the steel band 26B in order to effect reduction of the inner diameter of the sheath.
The inventors of the present invention have discovered that reducing the inner diameter of the sheath 14 proximal of the annulus 28 is advantageous in that the sheath can be allowed to remain freely rotatable with respect to the inner structure of the delivery system that effects proximal withdrawal of the sheath. Furthermore, the tensile strength of the sheath in the proximity of the annulus 28 remains unchanged due to the constant wall thickness of the catheter sheath in the proximity of the annulus 28.
FIG. 2A further depicts a pusher-guider tube 42 which is arranged side-by-side with the distal end 50 of the pusher tube 52 of the catheter device which extends all the way to the proximal end of the catheter device. The pusher tube 52 is conveniently provided as a PHYNOX™ or stainless steel hypo tube.
As shown in FIG. 2A, the pusher-guider tube 42, in a portion of its length between its distal end (not shown) and its portion at which the pusher-guider tube 42 is arranged side-by-side with the distal end 50 of the shaft pusher tube 52, exhibits slits through the wall thickness of the pusher-guider tube 42. These slits are preferably arranged in a helical string along the axial length of the pusher-guider tube 42. They are discontinuous, that is, discrete from one another, so that, typically, each slit in the string extends approximately two complete turns around the longitudinal axis of the pusher-guider tube 42. The portions of solid material, between each two adjacent spiral cuts in the helical string impart the pusher-guider tube 42 with sufficient torqueability in both senses of rotation of one end of the pusher guider tube relative to its other end.
Of course, the cuts can be arranged on the outer surface, and through the wall thickness of the pusher tube in other patterns, such as a sinusoidal pattern, helical pattern with varying pitch, circumferentially offset double or multiple helical or sinusoidal patterns, a pattern of cuts with finite length in which the cuts extend perpendicular, or slightly inclined to the long axis of the pusher-guider tube and in which axially adjacent cuts are circumferentially offset, etc. The spiral cut arrangement may be a double- or multi-helix design in which at least the second helix is circumferentially offset by 180° relative to the first helix.
The skilled person may select such slit patterns from stent designs that exhibit good axial elasticity and bendability, sufficient endwise compression resistance and sufficient torqueability. In other words, for the present invention, the slit pattern applied to the pusher-guider tube 42 is to be selected such that its bendability is increased, and the restoring forces causing the pusher-guider tube to assume its original shape, i.e. from a curved configuration when advancing it along a tortuous vessel to a straight configuration, are minimised (consistent with structural integrity).
The inner diameter of the pusher-guider tube 42 is typically at least 1.0 mm, and the outer diameter is typically 1.1 mm or more. The inner diameter and the outer diameter of the pusher guider-tube 42 is selected to provide, on the one hand, a sufficient gap between a guide wire extending through the lumen of the pusher-guider tube 42, thus reducing the likelihood of adhesion of the guide wire to the luminal surface of the pusher-guider tube 42, and, on the other hand, a sufficient gap between the abluminal Surface of the pusher-guider tube 42 and the luminal surface of the stent.
The above mentioned properties may even be achieved by changing the composition of the material, used for the pusher-guider tube 42 along its length. Moreover, the pusher-guider tube 42 may be made of a thin-walled stainless steel tube, or a stainless steel hypotube, which has been exposed to a thermal treatment process such to exhibit a 40% elongation at fracture, or greater at body temperature.
For achieving the above described properties, the pusher-guider tube 42 may be made of a thin-walled stainless steel tube that is fully or partially annealed. It is preferred that the annealing of various portions along the axial length of the pusher-guider tube 42 is such that the resistance of the portion radially inside the stent to bending is substantially less than the bending flexibility of the stent itself. Either a thin-walled stainless steel tube fully annealed to exhibit a 40% elongation at fracture, or greater at body temperature, or a thin-walled stainless steel tube fully or partially annealed and comprising non-continuous spiral cuts with varying pitch, or a thin-walled stainless steel tube not being annealed and having non-continuous spiral cuts with varying pitch, may be used for the portion of the pusher-guider tube 42 proximal of the stopper abutting the implant. Either the full axial length of the pusher-guider tube may be subjected to a heat treatment process, or only axial portions thereof.
The pusher annulus 40, as shown in FIG. 2A, comprises two parts. However, it is conceivable that it may comprise more than two parts. The proximal part 40B is made of metal, preferably stainless steel, such as 1.4301 or 1.4305 stainless steel, and is welded at its proximal chamfered end to the pusher-guider tube 42, as indicated by reference numeral 40C. However, the proximal metal part may be alternatively glued to the pusher-guider tube 42. The distal part 40A of the pusher annulus 40 is made of a polymer which is stiff enough to withstand the forces exerted by the abutting stent when proximally withdrawing the outer sheath 14. The polymer part 40A is preferably overmolded to the steel part 40B, however, other ways of connecting the polymer part 40A to the metal part 40B are conceivable.
As shown in FIG. 2A, a mechanical engagement interference fit is provided at the abutting portion of the polymer part 40A and the metal part 40B. The recessed portions of the polymer part 40A and the metal part 40B are not restricted to the shape as shown in FIG. 2A. Other interference fit designs are conceivable so long as dislodging of the polymer part 40A from the metal part 40B is prevented.
The heterogeneous radiocapacity helps to make the stent visible during intraluminal advancement, that is to say, to provide a material adjacent the stent that has a radiopacity which is different from that of the stent material. This helps in imaging the stent, and in identifying the position of the proximal end of the stent during intraluminal delivery.
To deploy the stent, the pull wire is pulled by an actuator at the proximal end of the system. A suitable actuator is described below, as part of a catheter-based delivery system illustrated herein.
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