GB2498514A

GB2498514A - Introducer assembly and method of sterilising such an assembly

Info

Publication number: GB2498514A
Application number: GB1200048.5A
Authority: GB
Inventors: Sebastian Hansen
Original assignee: Cook Medical Technologies LLC
Current assignee: Cook Medical Technologies LLC
Priority date: 2012-01-04
Filing date: 2012-01-04
Publication date: 2013-07-24
Also published as: GB201200048D0

Abstract

The assembly 10 includes a sheath 24 which is impermeable to gas and liquid for a substantial part of its extent. At a distal end 16 of the sheath 24 there is provided a device holding zone 26 which includes a plurality of holes 28 allowing the passage of sterilisation gas but not the passage of liquid therethrough. The introducer assembly 10 may hold a variety of medical devices, including implantable medical devices such as stents, stent grafts, vena cava filters as well as other implantable medical treatment devices and diagnostic tools. The holes 28 in the device holding portion 26 of the sheath 24 provide faster sterilisation of the contents of the introducer assembly 10.

Description

INTRODUCER ASSEMBLY AND METHOD OF STERILISING

SUCH AN ASSEMBLY

Technical Field

s The present invention relates to an introducer assembly and to a method of sterilising an introducer assembly.

Background Art

Introducer assemblies used, for example, deploying implantable medical devices endoluminally into a patient are generally assembled in a clean but non-sterile environment and then sterilised with a suitable sterilisation gas, such as ethylene oxide (ETO), vaporized hydrogen peroxide (VHF), nitrous oxide or other similar gases.

Whilst these gases are generally effective in sterilising introducer assemblies, problems arise with the length of time required for sterilisation, particularly in light of continuing trends to make such assemblies as compact as possible. The more compact the assembly, the smaller and fewer are the spaces within the lumen of the outer sheath of the assembly for the passage of sterilisation gas through the assembly. Small spaces increase the time it takes for the sterilisation gas to feed through the lumen of the outer sheath. This therefore results in an increase in the sterilisation times required to sterilise introducer assemblies and also for removal of the sterilisation gas prior to insertion into a patient. Furthermore, it is often desirable to sterilise a whole range of different introducer assemblies in a common sterilisation procedure, for instance at the very end of the stage of manufacture of such assemblies. However, with assemblies of different nature and dimensions, there is a need to effect sterilisation over different periods of time for different introducer assemblies in order to be able to ensure that even the most compact assemblies are fully sterilised. However, having to sterilise different assemblies over different lengths of time leads to complications in the production process.

Different devices and methods of sterilising medical components and introducer assemblies are disclosed, for example in: US-8,012,413, US-2010/0185270, US-7,762,044, US-7,434,372.

s Disclosure of the Invention

The present invention seeks to provide an improved introducer assembly and an improved method of sterilising an introducer assembly.

According to an aspect of the present invention, there is provided an introducer assembly including a carrier element including a proximal end and a distal end; a medical device carried at the distal end of the carrier element; an outer sheath including a wall and proximal and distal ends, the sheath covering the carrier element and medical device; wherein the medical device is located at the distal end of the sheath in a device holding zone of the sheath, the sheath having a plurality of holes in the wall thereof at least at the device holding portion, said holes allowing the passage of gas and vapour therethrough and being impervious to liquid, said introducer assembly being flexible for passage through a patient's vasculature.

The holes provided in the device holding portion at least ensure that sterilisation gas can reach into the outer sheath to sterilise the medical device without having to follow a long, tight and tortuous path from one or both of the ends of the outer sheath. As a result, the medical device can be sterilised more reliably and significantly faster than with prior art assemblies. Furthermore, given that the distance which the sterilisation gas has to pass to sterilise a medical device is very similar from one assembly to another (this being primarily dependent upon the diameter of the outer sheath and its length), different devices can be sterilised readily in a common sterilisation stage.

Advantageously, the holes are arranged in a regular array. This ensures that sterilisation gas can feed generally evenly through the sheath to the device, as well as ensuring that the sheath retains its characteristics of strength, flexibility, pushability and integrity.

In the preferred embodiment, a major portion of the length of the sheath is provided with no holes, the hole or holes in the wall of the sheath are located in a minor portion of the length of the sheath.

The provision of holes can ensure that the sheath retains its strength, s pushability and tractability.

The medical device may be one or more of: an implantable medical device, a diagnostic tool and a treatment device. Thus, the assembly could be for the implantation of a medical device, such as a stent, stent graft, vena cava filter, occluder and so on. The assembly could equally deploy a diagnostic device or a medical treatment tool including, for instance, a balloon catheter used for a variety of medical procedures including vascular dilatation, angioplasty, valvuloplasty and device deployment.

According to another aspect of the present invention, there is provided a method of sterilising an introducer assembly, which assembly includes a carrier element including a proximal end and a distal end; a medical device carried at the distal end of the carrier element; an outer sheath including a wall and proximal and distal ends, the sheath covering the carrier element and medical device; wherein the medical device is located at the distal end of the sheath in a device holding zone of the sheath, the sheath having a plurality of holes in the wall thereof at least at the device holding portion, said holes allowing the passage of gas and vapour therethrough and being impervious to liquid, said introducer assembly being flexible for passage through a patient's vasculature; the method including the steps of: locating the introducer assembly in a sterilisation container; supplying sterilisation gas and/or vapour to the container; allowing for sterilisation gas and/or vapour to pass into the sheath through at least the holes in the distal ends thereof, said sterilisation gas and/or vapour sterilising said medical device.

Preferably, the holes allow the passage of gas and/or vapour therethrough and are impervious to liquid.

Advantageously, the holes are arranged in a regular array, the sterilisation gas and/or vapour passing substantially radially evenly into the sheath through the holes, thereby to sterilise the medical device substantially evenly.

The method may be practiced on different introducer assemblies having different dimensions, components or characteristics, in which case the step of supplying sterilisation gas to the container is preferably carried out for a predetermined period of time, said period being consistent over a plurality of s different sterilisation processes for different introducer assemblies.

Advantageously, the step of locating the introducer assembly in a sterilisalion container includes locating the introducer assembly in transport packaging and sterilising the packaging with the introducer assembly.

Brief Description of the Drawinus

Embodiments of the present invention are described below, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows in schematic form an embodiment of introducer assembly; Figures 2 to 3 show in partial cross-section the distal end of embodiments of introducer assembly as per Figure 1; Figures 5 and 6 show in schematic form cross-sectional views of different embodiments of sheath; and Figure 7 shows in schematic form an embodiment of sterilisation system.

Description of the Preferred Embodiments

It is to be understood that in the accompanying drawings the embodiments depicted are not to scale and that the various elements shown would typically have different dimensions, both in absolute terms and also relative to one another.

Moreover, although in the accompanying figures the various components within the introducer assembly appear to be relatively generously spaced. In practice the entire assembly is very compact and there is little free space. It is to this issue of paucity of space that the disclosure herein is directed.

Referring first to Figure 1, there is shown the principal components of introducer assembly 10 in accordance with one embodiment of the present invention. The assembly 10 includes an elongated catheter assembly 12 having a proximal end 14 and a distal end 16. The catheter assembly 12 will typically have a length from around one half to around one and a half meters, sometimes longer, independence upon the intended application of the introducer assembly 10, typically the vessel which is to be treated. The catheter assembly 12 is designed to be passed endoluminally through the vasculature of a patient and is typically s introduced into the patient via the well know Seldinger technique.

The proximal end 14 of the introducer assembly 10 is retained outside the patient and includes an external manipulation unit 18 which is provided with, at least, control elements for operating the introducer assembly, one or more haemostatic valves for sealing the internal lumens of the assembly 10, as well as one or more ports for feeding components and fluids through the assembly 10, such as flushing fluid, guide wires and the like. These components are all well known in the art and are therefore not described in detail herein.

At the distal end 16 of the assembly 10 there is provided a dilator tip 20, again of typical construction, which is used to assist the passage of the introducer assembly into the patient. The dilator tip 20 typically includes an internal lumen which couples to a lumen of a carrier catheter (described in further detail below) for the passage of a guide wire 22 therethrough.

The catheter assembly 12 includes an outer sheath 24 which is fixed to the external manipulation unit 18 at the proximal end of the assembly 10 and which extends all the way to the distal end 16 of the assembly 10, in this embodiment ending just short of the body of the dilator tip 20. The outer sheath 24 is typically flexible so as to be able to curve around a patient's vasculature, but is also sufficiently strong so as to be pushable through the patient's vessels and also to as not to kink as it curves. Typically, the sheath 24 is a multi-layer construct including one or more layers of a polymeric material and one or more strengthening elements extending along substantially the entire length of the sheath 24. The strengthening element or elements could include an internal braiding, a coil of resilient material such as steel, and the like.

At the distal end 16 introducer assembly, the sheath 24 includes a device holding zone 26, which is the portion of the sheath 24 within which an implantable medical device, medical treatment device or medical diagnostic device is typically located for deployment within a patient. This device holding zone 26 may only be a few centimetres in length but could extend to 10, 20 or even 30 centimetres, possibly more, depending upon the length of the device held by the introducer assembly 10 and the extent to which that device is exposed within a patient's s vessel. The device holding portion 26 includes, in a preferred embodiment, a variety of holes 28 which extend through the walls of the sheath.

More specifically, the majority of the length of the sheath 24 is impermeable to liquid and gas/vapour as a result of the materials used for the sheath 24 and its construction. By contrast, the device holding portion 26 at the distal end 16 of the sheath 24 is permeable, in the example described below, to gas and/or vapour but not to liquid for reason of the size of the holes 28.

Referring now to Figure 2, there is shown an example of the distal end 16 of an introducer assembly 10 in accordance with the teachings of Figure 1. It will be appreciated, as explained above, that Figure 2 shows the principal elements of the distal end of the introducer assembly in schematic form and that these elements are not necessary to size, either in absolute terms or relative to one another. In most cases, the elements have been enlarged so as to emphasise their features.

The actual size of these elements will be apparent from below and from the common general knowledge of the person skilled in the art.

Referring specifically to Figure 2, the distal end 16 of the introducer assembly 10 and in particular of the sheath 24 is provided with a device holding zone 26 which has a plurality of holes or bores 28 extending through the extent of the wall of the sheath 24. In Figure 2, the device holding zone 26 of the sheath 24 is a single layer of sheath material without any further layers of strengthening elements within the zone 26. This is one way of implementing the teachings herein, although it is to be understood that other embodiments may continue the structure of sheath 24 even along of the device holding zone 26, that is a structure having one or more strengthening elements embedded within the sheath wall and possibly a plurality layers of polymeric material. In Figure 2 there are provided holes 28 in at least two longitudinal sets. Other embodiments may have a single longitudinal set of holes 28, while other embodiments may have a great number of sets. The holes 28 of a set or the sets may not necessarily extend parallel to the longitudinal axis of the sheath 24.

Within the sheath 24 there is provided, in this example, an elongated carrier element 30 which extends from the proximal end 14 of the assembly 10, typically s from external manipulation unit 18, all the way and attached to the dilator tip 20.

The carrier element 30 includes at least one lumen therein for accommodating a guide wire (not shown in Figure 2). Held on the carrier element 30 is, in this embodiment, a stent graft 32 formed of a tube of graft material which are attached, in a conventional manner, a plurality of stents 34. The assembly 10 also includes elements for holding the stent graft 32 to carrier 30 both in a radially compressed configuration as well as in position on the carrier clement 30. Such elements could include release wires, holding caps and so on, that is any of the elements commonly available in the art. Typically, there is provided little space between the carrier element 30 and sheath 24 for accommodating stent graft 32, in order to minimise the footprint of the introducer assembly 10 and in particular the diameter of the sheath 24. An introducer assembly of smaller diameter is easier to manipulate and pass through a patient's vasculature.

The holes 28 are of a diameter or size which is able to allow the passage of gas therethrough but are small enough to block the passage of liquid. The skilled person will readily be able to determine the appropriate size of the holes having regard to the gas and/or vapour to be used for sterilisation. In one embodiment, the holes 28 are made by laser cutting.

Referring now to Figure 3, there is shown another application of the embodiment of introducer assembly 10 of Figure 1. In this case, located within the sheath 24 is a balloon catheter having a medical balloon 42 at the distal end of the catheter 40 which, as can be shown in Figure 3, is wrapped around the catheter for location within the sheath 24. The balloon 42 may be a simple balloon but can equally be a cutting or scoring balloon, a valvuloplasty balloon or a balloon for deploying implantable medical devices such as stents, stent grafts and the like.

Again, as with the example of Figure 2, the balloon 42 would typically be wrapped relatively tightly onto catheter 40 with little space remaining within the sheath 24, at least in the device holding section 26. The features of the introducer assembly 10 shown in Figure 3 are the same as those described above.

Figure 4 shows another example of application of the introducer assembly of Figure 1, in this case for the deployment of a medical treatment device, s which is shown very much in schematic form in Figure 4. The device 50 can be any medical device which can be deployed by means of an introducer system of the type as shown in Figure 1. It may, for example, be an embolization device, a filter or any other medical device. It could equally be a medical treatment tool or a diagnostic device such as an endoscope. Although Figure 4 appears to show ample space within the sheath 24, in practice the space in minimised in order to reduce the diameter of the sheath 24 and thus of the introducer assembly 10.

As with examples of Figures 2 and 3, the features of the introducer assembly of Figure 4 are as described herein.

Referring now to Figures 5 and 6, there are shown two examples of arrangement of holes 28 in the device holding portion 26 of the sheath 24. In Figure 5, there is shown four sets of holes 28 arranged at even radial spaces around the sheath 24. In each set, it is envisaged that there would be holes 28 which extend along the entire length of the desired device holding portion 26 although, it will be appreciated, they could extend only for a portion of the device holding zone 26, preferably a major portion of this. The set of holes 28 extend substantially longitudinally along the axis of the sheath 24, although could extend at an angle to this axis. These characteristics of the holes 28 apply, of course, to all of the embodiments disclosed herein.

Figure 6 shows an example in which there are only provided two sets of holes 28, on opposite sides of the sheath 24, again for the whole or part of the length of the device holding zone 26. These lines of holes 28 could equally extend in the longitudinal direction along the sheath 24 or at an angle thereto.

Providing holes 28 within the sheath 24 can confer a number of advantages, in particular retaining the structural characteristics of the sheath 24, such as its flexibility, trackability, pushability, kink resistance and so on. It will also be appreciated that the number of holes 28 provided in the device holding zone of the sheath 24 and their arrangement may vary in dependence upon the nature of the device to be held in the introducer assembly 10.

Although the embodiments shown in Figures 5 and 6 show the holes extending radially towards the central axis of the sheath, in other embodiments, s the bore of the holes could extend at an angle to this. In the latter case, the sheath could be compressed to close off the holes and therefore retain sterilisation gas in the assembly until flushing prior to use.

Referring now to Figure 7, there is shown in schematic form an example of sterilisation system for sterilising the introducer assembly 10. Figure 7, shows the system in schematic form and only a part of it, that is that part holding the distal end 16 of the introducer assembly 10. Sterilisation of the introducer assembly 10 could be effected in a specialised sterilisation chamber for subsequent packaging in a sterile environment or could be with the introducer assembly 10 already in packaging used for storage and transportation purposes, in which case the assembly in its packaging are loaded into the sterilisation chamber. Referring to Figure 7, the example of introducer assembly shown holds an element 60, of undefined characterises to denote any of the devices which could be carried and held within the introducer assembly 10 as disclosed and contemplated herein.

The device 60 fills the sheath 24 with little spare space.

The sterilisation system provides container 62 within which the introducer assembly 10 is located and a source 64 of sterilisation gas or vapour, such as ethylene oxide (ETO), vaporized hydrogen peroxide (VHP), nitrous oxide or other similar gases. The sterilisation gas passes from the source into the chamber of container 62. Typically, the sterilisation gas or vapour is able to pass into the sheath 24 via the extremities of the sheath, that is its proximal and distal ends.

Where there is adequate space within the sheath 24, this flow of sterilisation gas or vapour into the sheath 24 will effect sterilisation within an adequate time period.

However, with regard to the device holding zone 26, as a result of the compactness of the components within the sheath 24 in zone 26, it is difficult for sterilisation gas or vapour to pass adequately through the entirety of zone 26 from the extremities of the sheath 24. In the embodiments disclosed herein, the sterilisation gas or vapour is able to pass through the hole 28, as depicted by the arrows in Figure 7, so as to feed directly into the zone 26 the sterilisation gas or vapour, thereby to sterilise faster the components held within the zone 26.

Sterilisation of the assembly 10 can be maintained until deployment of the s introducer assembly 10. In this regard since the holes 28 are small enough so as to be impervious or substantially impervious to liquid, there will be no liquid exiting the sheath 24 through the holes 26, such as flushing fluid or other liquid passing through or held within the sheath 24. Prior to deployment, the sterilisation gas is allowed to escape from within the assembly or otherwise is flushed out. In this regard, the preferred packaging, being pervious to sterilisation gas and/or vapour, can allow gradual escape of sterilisation gas from the point of manufacture to the time of use.

Above are described embodiments in which the device holding zone 26 of the sheath 24 is made pervious to sterilisation gas by a series of holes made within the sheath 24, which is otherwise gas impermeable. In another embodiment, the distal end of the sheath 24 and in particular the device holding portion of the sheath, could be made of a gas permeable material rather than from impermeable material of the type used for the other parts of the sheath 24.

The passages provided through the holes 28 for sterilisation gas into the sheath 24 can substantially speed up the process of sterilisation of the introducer assembly, particularly assemblies which hold devices in a very compact manner within the sheath.

Furthermore, the teachings herein also substantially standardise the length of time it can take in practice to sterilise different types of introducer assemblies and assemblies having different devices held therein, thereby enabling a substantially standard sterilisation process to be used for different introducer assemblies, in particular, to effect sterilisation of the different assemblies over a common and efficient timeframe.

It is to be understood that although the preferred embodiments described herein have holes only in the device holding zone of the sheath, the holes could extend for a major portion or the entire length of the sheath. Where the holes extend only for the device holding portion, they may extend over a length less than the length of the device being held, for the same length or for a greater length.

As will be apparent to the skilled person, the holes 28 allow for more rapid and standard sterilisation times as well as flushing times br removal of sterilisation S gas/vapour.

It will be appreciated that described above are various embodiments of the present invention and that the teachings herein are broader than the specific embodiments disclosed. It is also to be understood that the features of the different embodiments could be combined together.

Furthermore, although the claims are set out in single dependent form, it is to be understood that the features of the dependent claims can be combined with one another as if the claims has been written in multiple dependent form.

Claims

<claim-text>CLAIMS1. An introducer assembly including: a carrier element including a proximal end and a distal end; s a medical device carried at the distal end of the carrier element; an outer sheath including a wall and proximal and distal ends, the sheath covering the carrier element and medical device; wherein the medical device is located at the distal end of the sheath in a device holding zone of the sheath, the sheath having a plurality of holes in the wall thereof at least at the device holding portion, said holes allowing the passage of gas and vapour therethrough and being impervious to liquid, said introducer assembly being flexible for passage through a patient's vasculature.</claim-text> <claim-text>2. An introducer assembly according to claim 1, wherein the holes are arranged in a regular array.</claim-text> <claim-text>3. An introducer assembly according to claim 1, wherein the holes are located radially around the wall of the sheath.</claim-text> <claim-text>4. An introducer assembly according to claim 1, wherein a major portion of the length of the sheath is provided with no holes so as to be substantially impervious to fluid, gas and vapour along a majority of its length.</claim-text> <claim-text>5. An introducer assembly according to claim 1, wherein the holes are located solely at the distal end of the sheath.</claim-text> <claim-text>6. An introducer assembly according to claim 6, wherein the holes in the wall of the sheath are located only in the device holding portion of the sheath.</claim-text> <claim-text>7. An introducer assembly according to claim 1, wherein the wall of the sheath is made of a plurality of layers.</claim-text> <claim-text>8. An introducer assembly according to claim 1, wherein the sheath has a wall made of a plurality of layers including at least one strengthening element.s 9. An introducer assembly according to claim 8, wherein the strengthening element is a braid or coil.10. An introducer assembly according to claim 8, wherein the holes extend through the plurality of layers and the at least one strengthening element.11. An introducer assembly according to claim 8, wherein the distal end of the sheath is free of strengthening elements.12. An introducer assembly according to claim 1, wherein the medical device is one or more of: an irnplantable medical device, a diagnostic tool and a treatment device.13. A method of sterilising an introducer assembly, which assembly includes a carrier element including a proximal end and a distal end; a medical device carried at the distal end of the carrier element; an outer sheath including a wall and proximal and distal ends, the sheath covering the carrier element and medical device; wherein the medical device is located at the distal end of the sheath in a device holding zone of the sheath, the sheath having a plurality of holes in the wall thereof at least at the device holding portion, said holes allowing the passage of gas and vapour therethrough and being impervious to liquid, said introducer assembly being flexible for passage through a patient's vasculature; the method including the steps of: locating the introducer assembly in a sterilisation container; supplying sterilisation gas and/or vapour to the container; allowing for sterilisation gas and/or vapour to pass into the sheath through at least the holes in the distal ends thereof, said sterilisation gas and/or vapour sterilising said medical device.s 14. A method according to claim 13, wherein said holes allow the passage of gas and/or vapour therethrough and are impervious to liquid.15. A method according to claim 13, wherein the holes are arranged in a regular array, the sterilisation gas and/or vapour passing substantially radially evenly into the sheath through the holes, thereby to sterilise the medical device substantially evenly.16. A method according to claim 13, wherein the sterilisation gas and/or vapour is able to pass through at least one of the proximal and distal ends of the sheath.17. A method according to claim 13, wherein the medical device is one or more of: an implantable medical device, a diagnostic tool and a treatment device.18. A method according to claim 13, wherein the step of supplying sterilisation gas and/or vapour to the container is carried out for a predetermined period of time, said period being consistent over a plurality of different sterilisation processes for different introducer assemblies.19. A method according to claim 13, wherein the step of locating the introducer assembly in a sterilisation container includes locating the introducer assembly in transport packaging, said transport packaging being pervious to sterilisation gas and/or vapour, said sterilisation container being sterilised with the assembly.</claim-text>