Patent Description:
The use of implantable medical devices in the treatment of diseased vasculature and other body conduits has become commonplace in the medical field. Such devices can be surgically implanted in or delivered endoluminally to the treatment site. In the latter case, visualization of the vasculature and the device can be challenging. Typically, caregivers and/or operators use a catheter for injection contrast to aid in visualization during the treatment. Moreover, vessel hydration or delivery of medicaments to the anatomy in association with delivery of such devices may be desirable. A catheter has a profile that indicates what size introducer the catheter can be inserted through. Adding multi lumen capabilities to a catheter tends to increase the overall catheter profile. In some previously known catheters, an additional lumen means having multiple fixed lumen diameters (i.e., the lumen diameters do not change significantly under normal operating procedures) and thereby having an increased profile compared to a single lumen catheter. In some other previously known catheters, an expandable sheath is used as a secondary lumen and at least partially addresses the increased profile by allowing the expandable sheath to expand and contract.

These previously known catheters still have limitations and leave room for improvements, especially in difficult procedures. Therefore, it remains desirable to provide a multi-channel catheter that facilitates accurate and efficient endoluminal deployment of implantable devices and endovascular tools.

The invention is defined by independent claim <NUM> and subsequent dependent claims <NUM> - <NUM>.

Various examples of catheter assemblies and associated systems and methods, not forming part of the invention, in accordance with the present disclosure relate to medical devices with multiple lumens usable for delivery of fluid(s) to one or more desired locations in the anatomy. In some examples, a catheter assembly in accordance with the present disclosure is usable to deliver fluids (e.g., contrast solution or fluid) to desired location(s) in body lumens, such as the vasculature of a patient (e.g., in the region of a portosystemic shunt, the aorta, or other vasculature either venous or arterial).

In some examples, a catheter assembly in accordance with the present disclosure includes a sheath attached to an elongated member of a medical device (e.g., a shaft and/or hub of a catheter assembly) at one or more attachment location(s) to form one or more lumens for fluid delivery. Some examples relate to a catheter assembly having an elongated tubular element (e.g., a catheter shaft, a balloon catheter, etc.) with an outer surface, a first end and a second end, a length extending between the first end and the second end, and a lumen extending along the elongated element. A sheath surrounds at least a portion of the length of the elongated element, wherein the sheath comprises a wall thickness, an outer surface area, a first relaxed configuration and a second pressurized configuration. In some examples, the sheath is attached to the elongated element at opposing circumferential ends of the sheath and cooperates with the elongated element to form one or more channels along at least a portion of the length of the elongated element when the sheath is in the second pressurized configuration. ; In some examples, the sheath comprises at least one macroscopic aperture through the wall thickness. In some examples, the at least one macroscopic aperture(s) have a macroscopic aperture area, wherein the macroscopic aperture area of the macroscopic aperture(s) occupies <NUM>% or less of the surface area of the sheath.

The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure, and together with the description serve to explain the principles of the present disclosure.

In some examples, catheter assemblies according to the present disclosure are usable to deliver fluids to vasculature or other locations in a body. For example, a catheter assembly may transport contrast fluid within the body, or any of a variety of fluids including saline, medicaments (pharmaceutical or other therapeutic agents), blood, serum, or other fluids as desired.

In various examples, catheter assemblies described herein have an additional component or layer added along the catheter to aid in delivering fluids within the body. This additional layer may be surrounding at least a portion of an outer surface of the catheter. For example, as shown in <FIG>, a catheter assembly <NUM> has an elongate member <NUM> (e.g., a catheter, guidewire, tube, etc.), a hub <NUM> with a hub proximal side delivery port <NUM>, a hub distal side delivery port <NUM>, a hub proximal end fluid delivery port <NUM>, and a hub distal end <NUM> with a port, and an additional layer (e.g., a sheath <NUM>) along the catheter outer surface <NUM>. A catheter typically has an outside diameter and an inside diameter, thereby having a lumen at least partially along the catheter.

As shown in <FIG>, the catheter assembly <NUM> defines a catheter assembly length <NUM>. As also shown, the sheath <NUM> defines a first sheath length <NUM> (e.g., corresponding to a total length of the sheath <NUM> between proximal and distal ends) and a second sheath length <NUM> (e.g., corresponding to a length of the sheath <NUM> from a distal end of the hub to the distal end of the sheath <NUM>). As shown, the catheter assembly length <NUM> extends between hub proximal end port <NUM> and catheter assembly distal end <NUM> and measures between hub proximal end port <NUM> and catheter assembly distal end <NUM> longitudinally along elongated element <NUM> (a catheter as shown, although other elongated elements are contemplated as previously described). As also shown, the first sheath length <NUM> extends between sheath proximal end <NUM> and sheath distal end <NUM> longitudinally along catheter <NUM>. The proximal end <NUM> of sheath <NUM> may extend to any location along hub length <NUM> as desired. As shown, the second sheath length <NUM> is defined between hub distal end <NUM> and sheath distal end <NUM>. Sheath <NUM> may extend along a length portion of catheter <NUM> as desired (e.g., along catheter outer surface <NUM>) and along at least a portion of hub <NUM> as desired (e.g., along hub outer surface <NUM>).

The desired attachment location(s) between the elongate member <NUM> and the sheath <NUM>, the catheter assembly length <NUM>, the catheter effective length <NUM>, the first sheath length <NUM> and the second sheath length <NUM> may vary per application and therefore may vary sheath offset length <NUM>. For example, the catheter assembly length <NUM> may be <NUM> (in other cases the catheter assembly length may be <NUM>, <NUM>, or <NUM> or more). For example, the sheath offset length <NUM> may be <NUM>. In other cases, the sheath offset length <NUM> may be <NUM>, <NUM>, <NUM> or less. In a TIPS (Transjugular Intrahepatic Portosystemic Shunt) application, a sheath offset length <NUM> of <NUM> may be useful for a typical anatomy. Hub length <NUM> extends between hub proximal end port <NUM> and hub distal end <NUM>.

The sheath <NUM> and the sheath apertures <NUM> have associated surface areas. The sheath apertures <NUM> can encompass varying amounts of area and therefore varying ratios of the sheath <NUM> total surface area. For example, the sheath apertures <NUM> surface area may account for approximately <NUM>% of the total surface area of the sheath <NUM>. In other cases, the sheath apertures may account for <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or even less than <NUM>%. The area calculations are taken when the catheter assembly is in a non-pressurized state as shown in <FIG>. The sheath aperture areas and sheath areas can be measured using standard known area calculating techniques. A sheath aperture is considered macroscopic if fluid can be passed through the aperture by a syringe under normal clinical operating pressures.

In some examples (e.g., as shown in <FIG>, <FIG>, <FIG>, <FIG> and <FIG>) the sheath <NUM> is attached circumferentially to the catheter <NUM>, at a location distal to at least one of the macroscopic sheath apertures <NUM>. As shown, the sheath <NUM> is also attached circumferentially to another portion of the catheter assembly <NUM> at an opposing end of the sheath <NUM> (e.g., at an intermediate location on catheter <NUM>, at a distal end of catheter <NUM>, or at another location along catheter <NUM> as desired).

In various ways, a sheath can surround a catheter. For example, as shown in transverse cross section <NUM> of catheter assembly <NUM> in <FIG>, the sheath <NUM> may more tightly surround catheter <NUM>. Sheath inner surface <NUM> may be in contact entirely with catheter outer surface <NUM>, thereby having no significant voids or sheath pockets <NUM> (e.g., transverse cross section <NUM> of catheter assembly <NUM> in <FIG>). Alternatively, as shown in <FIG>, the sheath <NUM> may be more loosely fitted along the catheter <NUM>. Sheath inner surface <NUM> may partially contact catheter outer surface <NUM>, thereby creating sheath pockets <NUM> along the catheter outer surface <NUM>. The sheath pockets <NUM> tend to be more localized and not run a continuous channel between sheath apertures <NUM> and hub distal fluid delivery port <NUM>. In each of these examples, the sheath <NUM> is in a relaxed configuration (i.e., not pressurized by an externally supplied force, e.g., a syringe). Sheath <NUM> may subsequently be expanded by an externally supplied force (e.g., to produce an internal fluid pressure in the channel) supplied by an external pressure device (e.g., a syringe) to create a fluid channel(s) <NUM>, <NUM> as shown in transverse cross sections <NUM> of catheter assembly <NUM> in <FIG> and <FIG> (see also <FIG>).

In some examples, the sheath <NUM> is configured to be distended by an internal pressure and to elastically recover upon removal of the internal pressure. Additionally or alternatively, the sheath <NUM> can be loosely fitted around the catheter <NUM> such that upon internal pressurization the loose portions of the sheath <NUM> are expandable to a pressurized configuration and upon removal of the internal pressurization the loose portions of the sheath <NUM> return to the relaxed configuration. The sheath <NUM> is optionally formed of fluoropolymer materials, such as expanded PTFE ("ePTFE"), or other materials such as silicone, polyurethane, polyethylene terephthalate or others. In some examples, the sheath <NUM> includes one or more elastic layer(s) or component(s), such as a separate elastomeric layer (e.g., a silicone or polyurethane layer) or an elastomer component within a layer (e.g., silicone coated onto or imbibed within an ePTFE layer).

In some examples, the catheter assembly <NUM>, and in particular the sheath <NUM>, has a first relaxed configuration circumference and a second pressurized configuration circumference that is greater than the first relaxed configuration circumference. For example, as shown in <FIG>, <FIG>, and <FIG>, a length (e.g., a circumference) along sheath outer surface <NUM> in a pressurized configuration is greater than a length (e.g., a circumference) along sheath outer surface <NUM> in a non-pressurized configuration. In some examples, the sheath <NUM> transitions to the pressurized configuration upon application of an internal fluid pressure. After pressure (e.g., internal fluid pressure) has been released, the sheath returns towards its original non-pressurized configuration. As previously referenced, any of a variety of fluids may be used for pressurization, including contrast solution, saline, medicaments, blood, serum, or other fluids.

In various embodiments, a sheath may transition from a resting configuration towards a pressurized configuration upon pressurizing the sheath (e.g., with an internal fluid pressure). Transverse cross sections <NUM> of catheter assembly <NUM> (as shown in <FIG>, <FIG>, and <FIG>, <FIG>) show a sheath <NUM> in a relaxed, resting state against the catheter <NUM>. When the sheath is pressurized through at least one of two side hub ports (e.g., <NUM> as shown in <FIG>), the sheath <NUM> moves away from the catheter <NUM> towards a more pressurized, non-relaxed configuration, as shown in various pressurization stages as shown by <FIG>, <FIG>, and <FIG>. For example, a partial fluid channel(s) <NUM> may form, urging the sheath <NUM> away from the catheter <NUM>, as shown in transverse cross section <NUM> of catheter assembly <NUM> in <FIG>, when a continuous space forms from a hub port (e.g., hub distal fluid delivery port <NUM>) to sheath apertures <NUM>. The partial fluid channel(s) <NUM> may transition into a sheath full fluid channel <NUM>, as shown in transverse cross section <NUM> of catheter assembly <NUM> in <FIG> when the catheter assembly is in a pressurized configuration. The sheath full fluid channel <NUM> forms when a fluid urges the entire sheath inner surface <NUM> away from a contacting surface (e.g., a catheter outer surface <NUM> or hub outer surface <NUM>) entirely and forms a continuous space from a hub port (e.g., hub distal fluid delivery port <NUM>) and sheath apertures <NUM>. Alternatively, the partial fluid channel(s) <NUM> may form (<FIG>) and not transition into a sheath full fluid channel <NUM> (as shown in <FIG>). For example, by selectively keeping portions of the sheath <NUM> against catheter outer surface <NUM> (e.g., by tacking down or adhering portions of the sheath <NUM> to catheter <NUM> at desired attachment location(s) <NUM> as shown in <FIG>). The attachment location(s) <NUM> attach, press, or keep portions of the sheath <NUM> (or in some other fashion) against catheter outer surface <NUM>.

A catheter assembly may have multiple fluid channels. As shown by example in <FIG>, a catheter assembly <NUM> may have a first fluid channel (e.g., a catheter lumen <NUM>) associated with a fluid delivery port <NUM> (as shown in <FIG>) and a second fluid channel (e.g., <NUM>,<NUM>) that is associated with a fluid delivery port <NUM> (as shown in <FIG>). One or both of the fluid channels are configured to receive and convey pressurized fluids, for example.

In various ways, a sheath may be attached to a catheter. For example, the sheath <NUM> may be attached at one or more attachment location(s) <NUM>. In some examples, the sheath <NUM> is attached at sheath distal end <NUM> as shown in <FIG> and <FIG> at attachment location 402D, although intermediate or proximal locations are additionally or alternatively contemplated. The attachment location(s) <NUM> may be entirely around a catheter <NUM> circumference at a location along catheter effective length <NUM> as shown in <FIG> and <FIG>. Alternatively, the attachment location(s) <NUM> may not be sealed totally against the catheter <NUM> (e.g., not sealed against the catheter <NUM> at the sheath distal end <NUM>). In some examples where the attachment location 402D is not sealed totally against the catheter, the sheath <NUM> allows some fluid to travel along the sheath <NUM> and to exit past the sheath distal end <NUM> and in some cases exit through sheath apertures <NUM> and past sheath distal end <NUM>. The attachment location(s) <NUM> may help build pressure within the sheath <NUM> allowing the sheath to expand when fluid is injected. The attachment location(s) <NUM> also may help keep the sheath <NUM> at a fixed location along the catheter <NUM>.

The sheath <NUM> may also bound (surround) the catheter <NUM> but only partially around the catheter outer surface <NUM> for a given transverse cross section <NUM> as shown in <FIG> and <FIG>. This may help keep a lower profile than a sheath that entirely surrounds catheter <NUM>, while still allowing a fluid channel to form along the catheter <NUM> and sheath <NUM> and exit sheath apertures <NUM> at a fixed location along the catheter <NUM>. <FIG> shows a sheath <NUM> partially surrounding a catheter <NUM> with a sheath full fluid channel <NUM> (e.g., after being pressurized by an external pressure source).

<FIG> and <FIG> show a magnified longitudinal cross section view of hub <NUM>, catheter <NUM>, and sheath <NUM> in accordance with this disclosure (with <FIG> describing an enlarged portion of <FIG>). The hub <NUM> has a plurality of fluid delivery ports (first and second side ports as shown in <FIG>, <FIG> and <FIG>), including a hub distal delivery port <NUM> and a hub proximal delivery port <NUM>, each of which can be used to deliver a fluid to one or more locations (e.g., contrast solution or another fluid at two separate, first and second locations along the length of the catheter <NUM>). A fluid may be injected through the hub distal fluid delivery port <NUM> into a hub fluid space <NUM>. In one example, the hub fluid space <NUM> is a toroidal shape (e.g., in a transverse cross section taken transversely to hub fluid space length <NUM>), as shown in <FIG> and <FIG>. The hub fluid space <NUM> may vary along hub fluid space length <NUM> as shown in <FIG> (or alternatively may have constant dimensions along the hub fluid space length <NUM>). The toroidal shape may allow a fluid to more easily expand the sheath <NUM> in an annular fashion by allowing fluid to more easily fill sheath inner surface <NUM>. The fluid space <NUM> may have other features such as protrusions that may rifle or spin the fluid along the hub fluid space length <NUM> and along the sheath <NUM> and catheter <NUM>. In other examples, the hub fluid space <NUM> may be a channel or lumen that is not annular.

In various ways, sheath <NUM> may attach to hub <NUM>. In one example, as shown in <FIG>, the sheath <NUM> surrounds hub outside surface <NUM>. The sheath <NUM> is attached along hub outside surface <NUM> and sheath inner surface <NUM> at one or more attachment location(s) <NUM>, such as a proximal attachment location 402P, so fluid will not leak between the sheath <NUM> and the hub outside surface <NUM>.

In another example, the sheath <NUM> is sealed along hub fluid space <NUM>. Sheath outer surface <NUM> is sealed along hub fluid space inner surface <NUM>, as shown in <FIG>.

In still other examples, multiple sheaths (e.g., multiple, concentric sheaths) are attached to the hub <NUM> to form multiple fluid spaces. For example, <FIG> shows sheath <NUM> surrounding catheter <NUM> and sheath 104D concentrically surrounding sheath <NUM> and catheter <NUM> to form multiple sheath fluid channels. Hub <NUM> defines more than one fluid space, such as fluid space <NUM> and fluid space 500D. Each of the fluid spaces <NUM>, 500D is in communication with a fluid port (not shown) of the hub <NUM>. As shown, sheath outer surface <NUM> is sealed along hub fluid space inner surface <NUM> and sheath outer surface 105D is sealed along hub fluid space inner surface 502D. In various examples, the sheaths <NUM>, 104D are configured to deliver a fluid through the fluid channels defined between sheath inner surface <NUM> and the catheter outer surface <NUM> and between the sheath inner surface 200D and sheath outer surface <NUM>. The sheaths <NUM>, 104D may be different lengths and have different distal openings and/or macroscopic apertures as desired. Additionally, the sheath 104D is optionally secured to the sheath <NUM> at one or more desired attachment location(s).

<FIG> is a generalized schematic of venous anatomy in proximity of the liver. <FIG> generally illustrates a parenchymal tract <NUM> of the liver <NUM> between a portal vein <NUM> and hepatic vein <NUM>. For ease of illustration, not all anatomical features are to scale or represented (e.g., the vena cava), although such anatomical features are well understood as are methods of forming parenchymal tracts (e.g., in association with a Transjugular Intrahepatic Portosystemic Shunt (TIPS) procedure. In some medical procedures, for example in a Transjugular Intrahepatic Portosystemic Shunt (TIPS) procedure, after forming of a liver parenchymal tract <NUM> (<FIG>), catheter assembly <NUM> may be inserted into the vasculature and the tract <NUM> and utilized to visualize the tract <NUM> and length of the tract to determine how long of an endoprosthesis may be required to support the tract <NUM>. The catheter assembly <NUM> is placed in the tract <NUM> of liver <NUM> between portal vein <NUM> and hepatic vein <NUM>. The sheath apertures <NUM> can be located in the hepatic vein <NUM> and the catheter assembly distal end <NUM> can be located in the portal vein <NUM>, allowing fluid to be injected through ports (<NUM>,<NUM> as shown in <FIG>) and exit sheath apertures <NUM> and catheter assembly distal end <NUM> via catheter lumen <NUM> (may be used as a fluid channel), also as shown in <FIG>. The fluid can follow blood flow as indicated by arrows <NUM>. The fluid can be injected simultaneously at two different locations along the length of the catheter assembly <NUM> to visualize the hepatic vein <NUM> and portal vein <NUM> at the same time. Alternatively, the fluid can be injected at different times.

In various examples, catheter assembly <NUM> may incorporate other components. For example, catheter assembly <NUM> may incorporate an endoprosthesis. The endoprosthesis may be located along the elongated tubular element, (e.g., catheter shaft <NUM> or perhaps a balloon catheter shaft), between sheath distal end <NUM> and the elongated tubular element distal end (e.g., catheter assembly distal end <NUM>). This may be advantageous in various ways. For example, it may allow a user to not have to exchange catheter assembly <NUM> before implanting an endoprosthesis during a medical procedure.

In other medical procedures, for example a procedure where a catheter resides in a vasculature (arterial or venous) for a time sufficient to allow a catheter to adhere to a vessel, catheter assemblies described in the present disclosure may also prove to be useful. For instance, in a TAMBE (Thoracoabdominal Modular Branched Endoprosthesis) procedure, a catheter assembly <NUM> (as shown in <FIG>) could undesirably adhere to a vessel <NUM> (e.g., an iliac artery) at an adhesion, or attachment location <NUM> during the procedure.

A catheter assembly <NUM> according to this disclosure would allow a physician or user to inject a fluid into the sheath <NUM> and exit sheath apertures <NUM> and catheter assembly distal end <NUM> to help prevent adhesion to a vessel wall (e.g., by applying preventative hydration at one or more potential adhesion location(s) or by applying preventative hydration at one or more locations upstream of the potential adhesion location(s)). The hydration may hydrate the vessel tissue and/or may hydrate the catheter assembly (e.g., where one or more components of the catheter assembly includes a hydrophilic coating, such as a hydrophilic catheter shaft).

Additionally or alternatively, the catheter assembly <NUM> may be used to help in releasing the catheter assembly <NUM> from the vessel (e.g., iliac artery) at adhesion location <NUM> that the sheath <NUM> and/or catheter <NUM> is attached to. The rehydration may hydrate the vessel tissue and/or may rehydrate the catheter assembly (e.g., where one or more components of the catheter assembly includes a hydrophilic coating, such as a hydrophilic catheter shaft). The injected fluid may be dispensed in immediate proximity of the adhesion location for rehydration, or can follow blood flow as indicated by arrows <NUM>.

A second catheter assembly <NUM> in a procedure may become attached at an attachment location <NUM> as shown in <FIG>. The injected fluid may help release the catheter assembly <NUM> from the adhesion location(s) <NUM>. Also, as shown in <FIG>, catheter assembly <NUM> could be used in the same TAMBE procedure for imaging purposes. The sheath apertures <NUM> of sheath <NUM> may be located near one side of an implant end (e.g., endoprosthesis end <NUM>) and catheter assembly distal end <NUM> may be located near an implant opposing end (e.g., endoprosthesis end <NUM>). As previously referenced, any of a variety of fluids are contemplated for delivery with catheter assembly <NUM>, including contrast solution, saline, medicaments, blood, serum, or other fluids.

In various examples, the sheath <NUM> can be utilized to deliver a fluid between sheath inner surface <NUM> and the catheter outer surface <NUM>. In one example, the sheath can be infused with a contrast solution via one of the fluid delivery ports (<NUM>,<NUM>), although any of a variety of fluids including saline, medicaments, blood, serum, or other fluids are also contemplated. The fluid is pushed through one of the ports (<NUM>,<NUM>) to generate internal fluid pressure, along hub fluid space length <NUM>, and along sheath <NUM> creating a sheath fluid channel <NUM>,<NUM> (e.g., a partial fluid channel or a full fluid channel) as the sheath <NUM> enlarges (e.g., in diameter as shown in <FIG>, <FIG>, <FIG>) between a relaxed or resting state (e.g., diameter) and a full or pressurized state (e.g., diameter). The fluid may flow along the catheter assembly <NUM>, between one of the fluid delivery ports (<NUM>,<NUM>) and sheath apertures <NUM>, creating a sheath fluid channel <NUM>, <NUM> between the catheter outer surface <NUM> and the sheath inner surface <NUM>, until the fluid can exit sheath apertures <NUM> near the sheath distal end <NUM>. The fluid may also, or alternatively, flow along the catheter assembly <NUM> and exit catheter assembly distal end <NUM> via catheter lumen <NUM>. In some examples, the sheath transitions to the pressurized configuration upon application of an internal fluid pressure and returns towards the relaxed configuration and away from the pressurized configuration when the internal fluid pressure is released. When the fluid pressure has been released, (e.g., when the fluid has exited sheath aperture <NUM>) the sheath <NUM> can retract towards a more relaxed state. The sheath apertures <NUM> may be between a sheath outer surface <NUM> and a sheath inner surface <NUM> and therefore be in a sheath wall. Alternatively, the sheath <NUM> may have openings formed at the sheath distal end <NUM>, similarly to a partial fluid channel <NUM> as shown in <FIG>.

A catheter assembly according to present disclosure can be manufactured in various ways. One way is as follows. A <NUM> OD stainless steel mandrel was obtained and a distensible ePTFE film (e.g., an ePTFE film with an elastomer as taught by <CIT>) was obtained. The ePTFE film should have strength in a longitudinal direction, i.e., along length of the mandrel, and be distensible in a circumferential direction relative to the mandrel, in order to enable a fluid space to form when pressurized by an external source. Approximately <NUM> layers of the ePTFE film were wrapped around the circumference of the mandrel in the fashion of a cigarette wrap with an overlapping edge of the film oriented to be parallel to the longitudinal axis of the mandrel.

After the ePTFE film was wrapped onto the mandrel, loose edges were tacked down with a local heat source (Weller Soldering machine, Apex Tool Group, Apex, NC <NUM>, USA). The ePTFE film was heat treated on the mandrel with a heat source (e.g., a convection oven, Grieves Model NT-<NUM>, The Grieve Corporation, Round Lake, Illinois <NUM>-<NUM> USA) for <NUM> minutes at 300C. The mandrel with the ePTFE film was removed from the heat source and allowed to air cool. The ePTFE film (now an ePTFE tubular sheath) was removed from the mandrel by sliding the ePTFE tubular sheath off the mandrel. Sheath apertures were formed with a sewing needle that was heated for approximately <NUM> minute at 250C (other methods or tools may be used to create apertures) by penetrating the ePTFE sheath with the heated sewing needle.

A <NUM> outside diameter polymer tube with a <NUM> (i.e., <NUM> French) inner lumen, to be used as the catheter, and a dual port hub (as shown in <FIG>), were obtained. The hub was adhered to the polymer tube with an UV cure adhesive (other known methods of adhering a hub to a catheter may be used). The polymer tube had an effective length of <NUM> after the hub was overmolded onto the polymer tube. The ePTFE sheath (sheath) was pulled along the catheter (i.e., polymer tube) and attached to the hub with an adhesive (e.g., cyanoacrylate). The sheath was trimmed approximately <NUM> distal of the apertures in the sheath so the ePTFE sheath had a desired length (<NUM>) as measured from end of the sheath to distal end of the hub. The sheath was attached to the catheter with an adhesive (e.g., cyanoacrylate) at the trimmed location. In this way, a catheter assembly having a low profile fixed length sheath capable of being enlarged (e.g., diametrically) to create a fluid space along the sheath; and a catheter with infusion ports where at least one of the infusion ports cooperates with the sheath was made.

In addition to the teachings described above and claimed below, devices having different combinations of the features described above and claimed below are contemplated. As such, the description is also directed to other devices having any other possible combination of the dependent features claimed below.

Claim 1:
A catheter assembly (<NUM>) having a length comprising:
an elongate member (<NUM>) being a catheter having a first fluid channel (<NUM>);
a sheath (<NUM>) along the elongate member (<NUM>) and selectively attached to the elongate member (<NUM>), the sheath (<NUM>) having a first relaxed configuration and a second pressurized configuration and cooperating with the elongate member (<NUM>) to form a second fluid channel (<NUM>), the sheath comprising sheath apertures (<NUM>);
a fluid hub port (<NUM>) in communication with the first fluid channel (<NUM>) adapted to deliver a fluid through the first fluid channel (<NUM>) to a first location along the length of the elongate member (<NUM>); and
a hub port (<NUM>) in communication with the second fluid channel (<NUM>) adapted to deliver a fluid through the second fluid channel (<NUM>) to a second location along the length of the elongate member (<NUM>),
wherein the sheath (<NUM>) surrounds the elongate member such that the inner surface of the sheath partially contacts the outer surface of the elongate member, characterized in that
the sheath is loosely fitted along the elongate member (<NUM>) in the first relaxed configuration such that sheath pockets (<NUM>) are created along the elongate member (<NUM>) between the sheath (<NUM>) and the elongate member (<NUM>), the sheath pockets being localized and not running as a continuous channel between sheath apertures (<NUM>) and the hub port (<NUM>).