WO2023272352A1

WO2023272352A1 - Vascular access device for introducing a catheter

Info

Publication number: WO2023272352A1
Application number: PCT/AU2022/050672
Authority: WO
Inventors: David Michael Lane; Scott Ryan MURPHY; Nyan Ye KHIN; Rahul BANGUR
Original assignee: All Vascular Pty Limited
Priority date: 2021-06-29
Filing date: 2022-06-29
Publication date: 2023-01-05

Abstract

The present disclosure concerns a vascular access device (1) comprising a vascular access tube (2), such as a cannula, including a proximal end region (3), a distal end region (4) terminating in a tip (5) for insertion into a blood vessel (V) of a patient and a lumen (6) for introducing a catheter there-through into the blood vessel (V). A port (7) is provided at the distal end region (4) of the access tube (2) for passage of the catheter there-through into the blood vessel (V), wherein the port is operable between a closed state and an open state. The port (7) typically comprises part of a valve mechanism (8) which is adapted to operate the port (7) between the closed state and the open state. The tip (5) of the vascular access tube (2) preferably has an opening (9) that provides communication between the lumen (6) of the access tube (2) and the blood vessel (V) of the patient into which the tip (5) is inserted, whereby this opening (9) forms the port (7). The vascular access device (1) may also include a fixation mechanism (10) that is operable to secure or fix the distal end region (4) of the vascular access tube (2) to the blood vessel (V) to inhibit or prevent withdrawal of the tip (5) from the blood vessel (V) and/or to inhibit or prevent over-insertion of the tip (5) into the blood vessel (V). The fixation mechanism (10) is desirably configured to fix the opening (9) of the tip (5) at or adjacent a wall (W) of the blood vessel (V) at a point of insertion of the tip (5). The fixation mechanism (10) may also be configured to secure or fix the vascular access tube (2) such that the tube extends longitudinally at a predetermined angle (θ) with respect to the blood vessel (V) at a point of insertion of the tip (5). The predetermined angle (θ) may preferably be within the range of about 20 degrees to about 90 degrees. The disclosure includes a respective method of introducing a catheter with the vascular access device (1).

Description

VASCULAR ACCESS DEVICE FOR INTRODUCING A CATHETER Technical Field

[0001] The present disclosure relates to a vascular access device for introducing an intravascular device such as a catheter into a blood vessel. The vascular access device of the disclosure is particularly suited to use in percutaneous introduction or insertion of a catheter in a patient. The present disclosure further relates to a method of introducing a catheter in a patient.

[0002] As noted above, the vascular access device and the associated method of this disclosure are especially suited to percutaneous use, and it will be convenient to herein describe the vascular access device and associated method in this exemplary context. It will be appreciated, however, that the device and method are not limited to such a use or application, and that they may also be employed in a surgical procedure.

Background Art

[0003] Vascular access tubes for infusing a medicament and/or for introducing one or more catheters therethrough into a blood vessel of a patient are known. Some known vascular access tubes for insertion percutaneously into the vasculature are designed to be inserted with an appreciable length of the tube protruding into and aligning with the lumen of the blood vessel. This has the disadvantage, however, that disturbances and restrictions in blood flow through the vessel can be created by the length of tube that resides in the blood vessel, as it occupies a portion of the vessel cross-section equal to the cross-sectional area of the tube itself. However, even vascular access tubes which do not extend appreciably into or along the blood vessel may still have the disadvantage that the distal end region of the tube at or in the blood vessel provides for entry of blood into the tube and creates ‘dead space’ with eddying or little or no blood flow. The access tube may thus create significant ongoing thrombotic / thrombo-embolic, ischaemic and intimal hyperplasia risks while the access tube is in situ. Further, the risk of colonisation of device surfaces and eventual bloodstream infection resulting from such a colonisation is generally proportional to the blood-contacting surface area of the device.

[0004] In view of the above, therefore, it would be desirable to provide a new vascular access device that is suitable for percutaneous deployment or insertion, and that is able to reduce or substantially minimise or avoid unnecessary obstruction of the blood vessel or thrombotic risk. It would also be useful to provide a method of introducing a catheter that is particularly suited, though not limited to, use in percutaneous procedure.

Summary

[0005] According to one aspect, the present disclosure provides a vascular access device comprising: a vascular access tube including a proximal end region, a distal end region having a tip to be inserted into a blood vessel of a patient, and a lumen for introducing a catheter there-through into the blood vessel. A port is provided at the distal end region of the access tube for passage of the catheter there-through into the blood vessel, wherein the port is operable between a closed state and an open state.

[0006] In the open state, the port provides fluid communication between the lumen of the vascular access tube and the blood vessel for passage of the catheter through the port into the blood vessel. In the closed state, the distal end region or tip of the access tube is preferably substantially fully closed to seal the access tube or cannula against ingress of blood from the vessel. In this way, the vascular access device is designed for selective operation to open or to close the access port according to the current access requirements of the patient. With the distal end region or the tip of the access tube substantially closed, the vascular access device may provide a reduction in ongoing thrombotic / thromboembolic, ischaemic, and intimal hyperplasia risks while the device is in-situ.

[0007] In the context of the present disclosure, it will be appreciated by persons skilled in the art that a “vascular access tube” may be in the form of a cannula or an introducer sheath. In this regard, as noted above, the access tube may be suitable for introducing at least one catheter there-through into the blood vessel but also for infusing material into, and/or aspirating material from, the blood vessel. That is, the lumen of the access tube or cannula may be adapted for introducing an intravascular device and/or may be adapted for the extraction and/or introduction of fluid.

[0008] In an embodiment, operation of the port between the closed state and the open state is effected by an actuation, e.g., a manual actuation, performed by a user, such as a doctor or medical professional, at the proximal end region of the vascular access tube. The actuation at the proximal end region of the vascular access tube to operate the port may, for example, preferably include a movement in an axial (longitudinal) direction of the access tube, a rotary movement about the axis, or a combination of axial and rotary movements. In this context, it will be noted that the proximal end region of the vascular access tube is typically located extracorporeally (i.e., outside of the patient’s body) for use in introducing the one or more catheters (or some other intravascular device) there through into the blood vessel or for infusing material into, and/or for aspirating material from, the blood vessel.

[0009] In an embodiment, the vascular access device comprises a mechanism, such as a valve mechanism, which may include the port and is configured for operation of the port between the closed state and the open state. In this context, the “mechanism” in at least some embodiments may also be understood or described as a gate mechanism with which one or more gate member(s) adapted to close and/or seal the port may be moved to operate or transition the port between the closed state and the open state. For the purposes of the present disclosure, the “port” may be understood to comprise an aperture or an opening designed for passage of a catheter or some other intravascular device there-through.

[0010] The valve mechanism or gate mechanism structures have two main purposes: (i) to seal the vascular access tube or cannula against the patient’s bloodstream when the device is not in use, which includes facilitating exclusion of blood and/or fluid-locking of the cannula with a suitable fluid, like saline; and (ii) to allow passage of one or more intravascular device(s) (single or multiple) through the vascular access tube or cannula without damaging the intravascular device(s), the access cannula, or the blood vessel. This functionality is considered particularly preferred for the development of long-term vascular access systems where the port or opening of the cannula to the patient’s blood stream is directed upstream, i.e., into the oncoming blood flow, in the blood vessel. This is in contrast to traditional indwelling vascular access systems, where the cannula opening is almost universally oriented downstream or away from oncoming blood flow.

[0011] According to another aspect, the present disclosure provides a vascular access device, comprising: a vascular access tube including a proximal end region, a distal end region with a tip for insertion into a blood vessel of a patient, and a lumen for introducing a catheter there-through into the blood vessel; and a valve mechanism having a port at the distal end region of the access tube for passage of the catheter there-through into the blood vessel, wherein the valve mechanism is adapted to operate the port between a closed state and an open state for passage of the catheter through the port into the blood vessel.

[0012] In an embodiment, the port is provided in or formed by a member or a part of the valve mechanism that is configured to move to operate the port between the closed state and the open state. For example, the port could be formed in valve membrane, such as a self-closing valve membrane, whereby parts of the membrane are movable to open and close the port.

[0013] In an alternative embodiment, the port is provided in or formed by a member or a part of the valve mechanism that is configured to remain fixed or static, wherein one or more other parts of the valve mechanism are movable relative thereto to operate the port between the closed and open states.

[0014] In an embodiment, the vascular access device comprises a closure or cover member that is configured to substantially close the tip of the vascular access tube in the closed state. In this regard, the closure or cover member may preferably comprise a part of the valve mechanism and is movable to operate the port between the closed state and the open state. The closure or cover member is preferably configured to close and substantially seal the lumen and/or the tip of the vascular access tube in the closed state. Thus, in an embodiment, the vascular access device comprises a cover member that is integrated in the distal end region of the access tube and is movable relative to an opening defining the port to operate the port between the closed state and the open state. In this regard, the cover member may be axially slidable or rotatable relative to an opening to operate or move the port between the closed and open states. Preferably, the cover member substantially seals port in the closed state.

[0015] In an embodiment, the valve mechanism is configured to operate or transition the port between the closed state and the open state by the application of hydraulic pressure, preferably applied at the distal end region of the vascular access tube.

[0016] In an embodiment, the valve mechanism is configured to move from the closed state to the open state by insertion or introduction of an intravascular device, such as a catheter, through the lumen of the vascular access tube to the distal tip. In this way, the insertion of a catheter may operate to open the port. The valve mechanism is preferably biased to move to the closed state upon withdrawal or removal of the intravascular device from the lumen of the vascular access tube.

[0017] In an embodiment, the valve mechanism includes an actuation member at the proximal end region of the vascular access tube operably associated or connected with the distal end region of the vascular access tube. The actuation member is adapted for operation by a user to operate the port between the closed state and the open state. To this end, the actuation member may be configured to be moved by a user, preferably moved slidably and/or rotatably, between two positions respectively defining the closed state and the open state of the port.

[0018] In an embodiment, the valve mechanism includes a sleeve or sheath arranged within the lumen of the vascular access tube, desirably in closely fitting relationship. The sleeve or sheath, either itself or in combination with the access tube, preferably defines the port. Further, the sleeve or sheath may comprise the actuation member, or may be operably associated or connected with the actuation member. In this way, the sleeve or sheath is preferably movable, e.g., axially slidable, relative to the access tube to operate the port between the closed state and the open state.

[0019] In an embodiment, instead of or additional to a sheath or sleeve, it will be noted that the actuation member could be provided in the form of a flexible member, such as a cord or line, to be drawn (i.e. , pulled under tension) by a user at a proximal end region of the vascular access device, with the cord or line preferably extending from the distal end region. In this way, an actuating impulse can be imparted and/or transmitted via the tension force in the flexible member to the distal end region to operate the access port. Alternatively, the actuation member could be provided in the form of a rigid member, such as a rod or (partial) tube, to be pulled, pressed, rotated or otherwise moved by the user at the proximal end region of the vascular access device, with the rigid member (e.g. the rod or tube) connected or extending to the distal end region to transmit or impart the impulse applied by the user. In this way, the activation member could, for example, be provided as an internal sheath or sleeve (e.g., liner) which is configured to be inserted and/or retracted within the lumen of the access tube.

[0020] In an embodiment, the vascular access device may preferably include a fixation mechanism that is operable to secure or fix the tip of the vascular access tube within the blood vessel. More particularly, the fixation mechanism may operate to secure or fix the tip at or adjacent a wall of the blood vessel at a point of insertion of the tip into the blood vessel. Minimising intrusion of the access tube into the blood vessel thus reduces flow disturbances and restrictions in the accessed blood vessel, as well as the surface area of foreign device materials exposed to circulating blood. This vascular access device may thus provide further reduction in ongoing thrombotic / thromboembolic, ischaemic, and intimal hyperplasia risks while the device is in-situ compared to other access tube designs. Details of various embodiments of the fixation mechanism are described in the present Applicant’s International patent application no. PCT/AU2020/051121 , published as WO 2021/072506 A1 , the contents of which are incorporated herein by reference.

[0021] In an embodiment, the fixation mechanism comprises an intravascular part that is configured to engage with an inner surface of the wall of the blood vessel through which the tip is inserted to inhibit or prevent withdrawal of the tip of the vascular access tube from the blood vessel. To this end, the intravascular part is preferably configured to engage the inner surface of the blood vessel wall at a periphery of a breach in the wall through which the tip of the access tube is inserted. The fixation mechanism may further comprise an extravascular part configured to engage with an outer surface of the wall of the blood vessel tissue to prevent over-insertion of the access tube. Thus, the fixation mechanism can operate to provide a stable connection between the access tube and the blood vessel. That is, it can be designed to resist loads applied to the device in use, including unavoidable impulses associated with use, like blood pressure or transmitted forces from the use of catheters through the device, or inadvertent knocks or impulses applied to the device in use.

[0022] It will be appreciated, however, that the vascular access device may not include any fixation mechanism for securing or fixing the vascular access tube or cannula with respect to the blood vessel. A short segment or portion of the access tube or cannula may extend or protrude into the blood vessel with that segment or portion unsecured or free within the blood vessel. Such an arrangement allows for a range of configurations for the valve mechanism or gate mechanism at the distal end region of the access tube or cannula.

[0023] In an embodiment, the vascular access device may include a delivery sheath for assisting percutaneous insertion and positioning of the vascular access tube relative to the blood vessel. The delivery sheath typically accommodates or surrounds the vascular access tube and has a distal tip to be placed in the blood vessel (e.g., in a variation of the Seldinger technique) and via which the tip of the vascular access tube is introduced through the wall of the blood vessel.

[0024] In particular embodiments, the vascular access device of this disclosure aims to balance the requirements of providing a reliable and effective closure or sealing of the port in a closed state to exclude ingress of blood into the access tube or cannula when the port is in the closed state, and providing for the port to be openable with sufficiently low force to avoid inadvertent damage to any one or more of an intravascular device, the vascular access device itself, and (of course) the patient (e.g. the wall of the blood vessel) during deployment of the intravascular device. In some cases, the force required to initially break a seal of, and thereby open, particular gate elements or valve elements forming a closure of the port may be significantly higher than a force required to maintain those gate elements or valve elements in an open position thereafter. For this reason, specialized guidewires or trocar elements optimized for this purpose may be useful as tools for initially opening / unsealing the gate elements or valve elements to operate or transition the access port to the open state, after which those tools may be exchanged for standard guidewires and intravascular devices.

[0025] According to a further aspect, the invention provides a vascular access device, comprising: a vascular access tube having a proximal end region, a distal end region having a tip to be inserted into a blood vessel of a patient, a lumen along a length of the access tube for introducing a catheter there-through into the blood vessel, and a port at the distal end region of the access tube for passage of the catheter there-through into the blood vessel; and an actuator for operating the port between a closed state for sealing the lumen from the blood vessel and an open state for introducing the catheter into the blood vessel.

[0026] In an embodiment, the vascular access tube comprises a cover member that is movable relative to the port to operate the port between the closed state and the open state port, and wherein the actuator is configured to effect relative movement of the cover member to the port.

[0027] In an embodiment, the actuator is configured to apply an hydraulic pressure to operate the port between the closed state and the open state, preferably at the distal end region of the vascular access tube. In an embodiment, the actuator is configured to impart an axial movement or a rotational movement to the cover member to operate the port between the closed state and the open state.

[0028] In a still further aspect, the present disclosure provides a method of introducing a catheter into a blood vessel of a patient, the method comprising steps of: inserting a vascular access tube into a patient, the access tube comprising a proximal end region, a distal end region having a tip to be inserted into a blood vessel of the patient, and a lumen for introducing a catheter there-through into the blood vessel, wherein an access port is provided at the distal end region of the tube for passage of the catheter there-through into the blood vessel; operating a valve mechanism (or a gate mechanism) to operate the port from a closed state to an open state to provide fluid communication between the lumen of the vascular access tube and the blood vessel; and inserting the catheter from the proximal end region through the lumen of the access tube for passage through the port into the blood vessel.

[0029] In a preferred embodiment, the step of inserting the vascular access tube into the patient, which is preferably performed percutaneously, comprises introducing the tip of the access tube through the wall of the blood vessel over a guidewire, optionally with the aid of a dilator. This may, for example, be a variation of the Seldinger technique. It will be noted that, while the step of inserting the vascular access tube into the patient is desirably performed percutaneously (i.e. , non-surgically through the skin), a small initial surgical procedure could be needed to expose the vessel prior to the step of inserting the vascular access tube in a trans-vascular manner. This may, for example, depend on the location of the blood vessel into which the vascular access device is to be inserted; for example, the vessel may not be readily accessible percutaneously.

[0030] In an embodiment, the step of inserting the vascular access tube into the patient may comprise introducing the vascular access tube via a delivery sheath, which may be inserted percutaneously at the intended site of implantation. The vascular access tube may be introduced through an interior of the sheath to the site for inserting the tip of the vascular access tube through the breach in the wall of the blood vessel. It will be noted that the delivery sheath may optionally also be inserted via preliminary surgical cutdown followed by trans-vascular introduction in a variation of the Seldinger technique. [0031] In an embodiment, the step of operating the valve mechanism to vary the port from the closed state to the open state includes moving an actuation member at the proximal end region of the access tube operably associated or connected with the distal end region of the vascular access tube. To this end, the actuation member is preferably movable, e.g., slidably or rotatably movable, between two positions which respectively define or correspond to the closed state and the open state of the access port.

[0032] In an embodiment, the method further comprises a step of applying suction to the lumen upon operating the port from the closed state to the open state for aspirating any fibrin / thrombus material accumulated at the tip of the access tube prior to inserting the catheter.

[0033] In an embodiment, the method further includes a step of activating a fixation mechanism provided at the distal end region of the vascular access tube, preferably at or in the vicinity of the tip, to secure or fix the distal end region of the access tube with respect to the patient, whereby the fixation mechanism secures or fixes the tip of the access tube at or adjacent the wall of the blood vessel at a point of entry of the tip through the wall.

Brief Description of the Drawings

[0034] For a more complete understanding of the disclosure and advantages thereof, exemplary embodiments are explained in more detail in the following description with reference to the accompanying drawing figures, in which like reference signs designate like parts and in which:

Fig. 1 is a schematic perspective view of a vascular access device according to a first embodiment of the disclosure shown with the port in a closed state;

Fig. 2 is another schematic perspective view of the vascular access device of Fig. 1 shown with the port in an open state;

Fig. 3 is a schematic side view of the vascular access device of Fig. 1 deployed in a blood vessel with the port in a closed state;

Fig. 4 is a schematic side view of the vascular access device of Fig. 1 deployed in a blood vessel with the port in an open state; Fig. 5 is a schematic side view of a vascular access device according to a second embodiment shown deployed in a blood vessel with the port in an open state;

Fig. 6 is a schematic side view of a vascular access device according to a third embodiment shown deployed in a blood vessel with the port in an open state;

Fig. 7 is a schematic front view of the vascular access device as shown in Fig. 6;

Fig. 8 is a schematic side view of a vascular access device according to a fourth embodiment shown deployed in a blood vessel with the port in a closed state;

Fig. 9 is a schematic side view of the vascular access device of Fig. 8 shown with the port in an open state;

Fig. 10 is a schematic side view of a vascular access device according to a fifth embodiment shown deployed in a blood vessel;

Fig. 11 is a schematic end view of the vascular access device of Fig. 10 shown with the port in a closed state;

Fig. 12 is a schematic end view of the vascular access device of Fig. 10 shown with the port in an open state;

Figs. 13a to 13c are schematic side views of the distal end region of a vascular access device according to a sixth embodiment transitioning from a closed state to an open state;

Figs. 14a to 14c are schematic end views of the distal end region of the vascular access device in Figs. 13a to 13c transitioning from the closed state to the open state;

Figs. 15a to 15c are schematic side views of the distal end region of a vascular access device according to a seventh embodiment transitioning from a closed state to an open state;

Figs. 16a and 16b are schematic side views of a distal end region of a vascular access device according to an eighth embodiment in a closed state and open state;

Figs. 17a and 17b are schematic side views of a distal end region of a vascular access device according to a ninth embodiment in a closed state and an open state; Figs. 18a and 18b are schematic side views of a distal end region of a vascular access device according to a tenth embodiment in a closed state and an open state;

Figs. 19a and 19b are schematic side views of a distal end region of a vascular access device according to an eleventh embodiment in a closed state and open state;

Figs. 20a and 20b are schematic side views of a distal end region of a vascular access device according to a twelfth embodiment in a closed state and open state;

Figs. 21a and 21 b are schematic side views of a distal end region of a vascular access device according to a thirteenth embodiment in a closed state and open state;

Figs. 22a and 22b are schematic side views of a distal end region of a vascular access device according to a fourteenth embodiment in a closed state and open state;

Figs. 23a and 23b are schematic side views of a distal end region of a vascular access device according to a fifteenth embodiment in a closed state and open state;

Figs. 24a and 24b are schematic end views of a distal end region of a vascular access device according to a sixteenth embodiment in open and closed states;

Figs. 25a and 25b are schematic end views of a distal end region of a vascular access device according to a seventeenth embodiment in open and closed states; and

Fig. 26 is a flow diagram which schematically represents a method according to any of the embodiments of the disclosure.

[0035] 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. The drawings illustrate particular embodiments and together with the description serve to explain the principles of the present disclosure. Other embodiments and many of the attendant advantages will be readily appreciated as they become better understood with reference to the following detailed description.

[0036] It will be appreciated that common and/or well understood elements that may be useful or necessary in a commercially feasible embodiment are not necessarily depicted in order to facilitate a more abstracted view of the embodiments. The elements of the drawings are not necessarily illustrated to scale relative to each other. It will also be understood that certain actions and/or steps in an embodiment of a method may be described or depicted in a particular order of occurrences while those skilled in the art will understand that such specificity with respect to sequence is not actually required.

Detailed Description of the Embodiments

[0037] With reference firstly to Figs. 1 to 4 of the drawings, an example of a vascular access device 1 according to a first embodiment of the disclosure is illustrated. The vascular access device 1 comprises a vascular access tube 2, such as a cannula, with a proximal end region 3, a distal end region 4 terminating in a tip 5 for insertion into a blood vessel V of a patient, and a lumen 6 for introducing a catheter (not shown) there through into the blood vessel V. As best seen in drawing Figs. 1 and 2, an access port 7 is provided at the distal end region 4 of the access tube 2 for passage of the catheter there-through into the blood vessel V. In this embodiment, the access port 7 forms part of a valve mechanism 8 and, as will be explained in more detail below, the access port 7 is operable via the valve mechanism 8 between a closed state (seen in Figs. 1 and 3) and an open state (seen in Figs. 2 and 4) for passage of the catheter through the port 7 into the blood vessel V.

[0038] Referring to drawing Figs. 3 and 4, the vascular access device 1 is shown in a deployed condition after having been inserted percutaneously through the skin and sub cutaneous tissue T of the patient to penetrate the wall W of the blood vessel V. The tip 5 of the vascular access tube 2 typically has an opening 9 that provides communication between the lumen 6 of the access tube 2 and the blood vessel V into which the tip 5 is inserted. The vascular access device 1 further includes a fixation mechanism 10 that is operable to secure the distal end region 4 of the vascular access tube 2 with respect to the blood vessel V. The fixation mechanism 10 includes an intravascular part 11 and an extravascular part 12. The intravascular part 11 comprises a member or element 13 in the form of a generally annular disc or flange deployed to engage an inner surface of the wall W of the blood vessel V and the extravascular part 12 comprises a member or element 14 also in the form of a generally annular disc or flange deployed to engage an outer surface of the wall W of the blood vessel V. In this way, the wall W of the blood vessel may be sandwiched between the intravascular and extravascular parts 11 , 12 to inhibit or prevent withdrawal of the tip 5 of the cannula 2 from the blood vessel V and to inhibit or prevent over-insertion of the tip 5 into the blood vessel V too. As seen in these drawing Figs. 3 and 4, the fixation mechanism 10 may be configured to secure or fix the cannula 2 such that it extends longitudinally at a predetermined angle Q with respect to the blood vessel V at a point of insertion of the tip 5. The predetermined angle Q may be in the range of about 20 degrees to about 90 degrees, more preferably in the range of about 30 degrees to 70 degrees, especially about 40 degrees to 60 degrees. By angling the cannula 2 in this way, the catheter or other intravascular device can be more readily introduced to extend along a lumen of the blood vessel V. This can be facilitated further by arranging the port 7 to face in an axial direction of the lumen of the blood vessel V. As noted above, many details and embodiments of the fixation mechanism 10 are described in the Applicant’s International patent application no. PCT/AU2020/051121 , published as WO 2021/072506 A1 , the contents of which are incorporated herein by reference. As such, the fixation mechanism 10 will not be specifically described here in further detail.

[0039] With reference again to Figs. 1 and 2 of the drawings, the access port 7 can be seen to be formed as a generally oval-shaped opening in a distal end portion of an inner sleeve or sheath 15 (i.e. , inner cannula) arranged in a close-fitting relationship within the lumen 6 of the cannula or access tube 2. One or more internal gaskets or seals (not shown) between the access tube 2 and the inner sleeve or sheath 15 (i.e., between the cannulas 2, 15) prevent leakage through the slight gap between them. A proximal end portion of the inner cannula 15 emerges from the proximal end region 3 of the access tube or outer cannula 2 and presents an actuating member in the form of a cap 16 with a circumferentially extending shoulder or flange 17. The sleeve or sheath 15 (and cap 16) is movable, e.g., slidable, within the lumen 6 of the outer cannula or access tube 2 in a longitudinal or axial direction as indicated by the double headed arrow A in Fig. 1. In this way, the inner cannula 15 and actuating cap 16 form part of the valve mechanism 8 and are operable to move the access port 7 between the closed state (shown in Figs. 1 and 3) and the open state (shown in Figs. 2 and 4). With the inner sheath 15 and cap 16 in the retracted position seen in Figs. 1 and 3, a closed end face 18 of the inner sleeve or sheath 15 is substantially ‘flush’ with, and substantially fully closes or obscures, the opening 9 in the tip 5 of the outer cannula or access tube 2. With the inner sheath 15 and cap 16 in the advanced or depressed position seen in Figs. 2 and 4, the distal end portion of that inner cannula 15 is advanced into the blood vessel through the opening 9 in the tip 5 of the outer cannula 2 such that the access port 7 is exposed and in an open state for passage of a catheter there-through into the blood vessel V. [0040] In this regard, it will be appreciated that the catheter may be introduced through the proximal end region 3 of the vascular access tube 2, e.g., through an axial opening (not shown) provided in the cap 16 into the inner cannula 15. Typically, a guidewire will be introduced in this way into the blood vessel V as a preliminary step and the catheter will then be introduced into the blood vessel over the guidewire in a subsequent step. A possible disadvantage of the vascular access device 1 of this embodiment is that the distal end portion of inner cannula 15 remains within the vessel V in the blood flow while the catheter (not shown) is deployed through the device 1 . Thus, this may create some blood flow disturbance and restriction in the blood vessel, and the surface of the device may provide some thrombotic / thrombo-embolic, ischaemic and hyperplasia risks. The vascular access device 1 is preferably configured for introducing just a single catheter, such that the cannula 2 is preferably of relatively small dimensions; for example, with an outer diameter in the range of about 3 mm to about 8 mm, and preferably about 4 mm to about 6 mm. It will be noted, however, that the lumen 6 of the cannula 2 may be suitable or sized for introducing more than one catheter into the blood vessel V.

[0041] Referring to Fig. 5 of the drawings, a second embodiment of a vascular access device 1 is illustrated. In this embodiment, the inner cannula 15 is replaced by an axially displaceable rod or stem element 15' which connects to a gate member, provided in the form of a plate member 18', sized and shaped to closely fit the opening 9 in the tip 5 of the cannula or access tube 2 - i.e. , in a similar manner to the closed end face 18 of the inner cannula 15 in the embodiment of Figs. 1 to 4. That is, the plate member 18' forms a closure that substantially fully closes or obscures the opening 9 in the tip 5 of the cannula or access tube 2. The actuating member provided in the form of the cap 16 with flange 17 may remain unchanged in this embodiment. Furthermore, in this embodiment, the access port 7 may be considered equivalent to the opening 9 in the cannula 2 or it may be considered the gap that opens between the tip 5 of the cannula 2 and the plate member 18' when the gate or plate member 18' is advanced into the blood vessel V, as shown in Fig. 5. In this embodiment, an upper surface of the gate member 18' has a curved profile for guiding or directing a catheter (not shown) along a lumen of the blood vessel V during its introduction through the port 7. Again, while the catheter is deployed through the device 1 , the rod or stem element 15' and the plate member 18' remain within the vessel V and in the blood flow. Flowever, compared to the embodiment of Figs. 1 to 4, these elements may create less blood flow disturbance and less restriction in the blood vessel V, and they may present a smaller surface area for the thrombotic / thromboembolic, ischaemic and intimal hyperplasia risk. Even if there were to be some accumulation of thrombus material on the plate member 18', upon operating the port 7 from the closed state to the open state, a suction may be applied to the lumen 6 at the proximal end region 3 of the cannula 2 to aspirate any thrombus material or fibrin accumulated at the tip of the access tube 2 prior to inserting the catheter into the blood vessel V. Operating the valve mechanism 8 to open the port 7 immediately creates a relatively large gap at the opening 9 in the tip 5 that facilitates application of suction to capture thrombus, fibrin and/or other material deposited on the blood-contacting end of the device 1.

[0042] With reference now to drawing Figs. 6 and 7, a third embodiment of a vascular access device 1 is illustrated. In this embodiment, the gate member 18' or the end plate member 18' is mounted on thin, axially displaceable lateral strut members 15". These strut members 15" present very little frontal or ‘bluff surface area to restrict blood flow through the vessel V and the end plate member 18' is advanced to the opposite vessel wall W (i.e. , out of the blood flow) when the port 7 is in the open state, as illustrated. This embodiment is thus again configured to minimise or reduce blood flow disturbance, restriction in the blood vessel V, and/or thrombotic / thromboembolic, ischaemic, and intimal hyperplasia risk. Again, however, even if thrombus material did accumulate on the plate member 18', a suction could be applied to the lumen 6 at the proximal end region 3 of the cannula 2 to aspirate any thrombus material or fibrin accumulated at the tip of the access tube 2 on operating the port 7 from the closed state to the open state and prior to inserting the catheter into the blood vessel V.

[0043] Referring to drawing Figs. 8 and 9, a fourth embodiment of a vascular access device 1 is illustrated. In this embodiment, the actuation of the valve mechanism 8 for operating the access port 7 involves a rotary or rotational movement instead of the axial longitudinal displacement of the previous embodiments. Specifically, a gate member 18’ or plate member 18’ again forms a closure or cover for the port 7 which is substantially equivalent to the opening 9 in the tip 5 of the cannula 2. The end plate member 18’ of this embodiment is mounted to pivot or rotate from the position shown in Fig. 8, in which the port 7 is in a closed state, to the position shown in Fig. 9, in which the port 7 is in an open state. The pivoting or rotation may occur about a substantially vertical axis (i.e., in the plane of the drawing sheet) or may alternatively occur about an axis extending perpendicularly into a plane of the drawing sheet (i.e., in the manner of a hinged flap). This embodiment again presents very little obstruction to blood flow in the open state as well as low thrombotic / thromboembolic, ischaemic, and intimal hyperplasia risk.

[0044] With reference now to drawing Figs. 10 to 12, a fifth embodiment of a vascular access device 1 is illustrated. In this embodiment, actuation of the valve mechanism 8 for operating the access port 7 again involves a rotary or rotational movement instead of the axial longitudinal displacement of the first, second, and third embodiments. In this embodiment, the cannula or access tube 2 is permanently partially closed at its tip 5 by a generally semi-circular panel 9', such that the opening 9 in the tip 5 of the cannula 2 is likewise generally semi-circular (or semi-elliptical). As with the embodiment of Figs. 1-4, the valve mechanism 8 includes an inner sleeve or sheath 15 (i.e. , inner cannula) in a close-fitting relationship within the lumen 6 of the cannula or access tube 2. Again, one or more internal gaskets or seals (not shown) between the access tube 2 and the inner sleeve or sheath 15 (i.e., between the cannulas 2, 15) may prevent leakage through the slight gap between them. A proximal end portion of the inner cannula 15 again emerges from the proximal end region 3 of the access tube or outer cannula 2 and presents an actuating member in the form of a cap 16 with a circumferentially extending shoulder or flange 17. In this case, however, actuation of the cap 16 is by rotation. Similarly with the outer cannula 2, in this embodiment a distal end face 18 of the inner cannula 15 is half- closed - again via a fixed, generally semi-circular (or semi-elliptical) end plate member. In the closed state of the port 7 seen in Fig. 11 , the semi-circular opening 9 in the outer cannula 2 is covered and/or obscured by the distal end face 18 of the inner cannula 15. When the inner cannula 15 is rotated via the actuating cap 16 by 180 degrees about the longitudinal axis X of the device 1 , however, the end face 18 is rotated into overlapping alignment with the semi-circular panel 9' such that the semi-circular opening 9 is fully unobscured. This then corresponds to the open state of the port 7 seen in Fig. 12. This embodiment once more presents minimal obstruction to blood flow in the open state as well as a low thrombotic / thromboembolic, ischaemic and hyperplasia risk. It does, however, present a smaller-sized port 7 or opening 9 for introducing the catheter into the blood vessel V.

[0045] Referring to drawing Figs. 13a to 13c and Figs. 14a to 14c, a sixth embodiment of a vascular access device 1 is illustrated. Like the fifth embodiment just described, this embodiment includes a port 7 formed as an opening in a distal end region 4 / distal tip 5 of an outer cannula 2 and, again, actuation of the valve mechanism 8 for operating the access port 7 involves a rotary or rotational movement. In particular, an inner sleeve or sheath 15 (i.e., inner cannula 15) within the outer cannula 2 includes a closure element or gate element for obscuring the port 7. As shown in Figs. 13a and 14a, the port 7 is in a closed state covered on its inner side by the closure element or gate element 18. As the inner sleeve or sheath 15 is rotated clockwise (see Figs. 13b and 14b) relative to the outer cannula 2, the port 7 moves towards the open state. A rotation of the inner sleeve or sheath 15 through 90 degrees to the position shown in Figs. 13c and 14c then results in the access port 7 being in a fully open state, whereby it is unobscured by the closure element or gate element 18. As an alternative to manually rotating the secondary, inner sleeve or cannula 15 to move the closure element 18, an electric or hydraulic actuator system may be provided. In this embodiment, the access port 7 is provided in a side wall of the access tube or outer cannula 2. It is an oval shaped opening and is oriented to face into the bloodstream within the blood vessel, as was the case in the embodiment of Figs. 1 to 4. Preferably, internal surfaces of the cannula 2 adjacent the opening of the port 7 are shaped to guide or direct an intravascular device (e.g., a catheter, not shown) towards and through the port 7, as in the second embodiment of Fig. 5.

[0046] Drawing Figs. 15a to 15c illustrate a seventh embodiment of a vascular access device 1. In this embodiment, the access port 7 is again an oval-shaped opening in the side wall at a distal tip 5 of the access tube or cannula 2. Further, a closure element or gate element 18 provided internally of or within the access tube or cannula 2 forms a sliding cover that operates or transitions the port 7 between a closed and an open state. In contrast to the previous embodiment, however, the closure element / gate element 18 in this case operates via axial or longitudinal movement. For example, another sleeve or inner cannula 15 or a rod or stem element 15' (as in Fig. 5) may be provided for axial or longitudinal displacement of the closure element / gate element 18 from the closed state seen in Fig. 15a via an intermediate (half open, half closed) position in Fig. 15b to the open state seen in Fig. 15c, and back again. The actuation of the closure element / gate element 18 may once more be manual, e.g., via a cap 16 at the proximal end region 3 of the device 1 , or may be automatic, e.g., electrically or hydraulically actuated. Again, also, internal surfaces of the cannula 2 adjacent the side-wall opening of the port 7 are preferably shaped to guide or direct an intravascular device (e.g., a catheter, not shown) towards and through the port 7. [0047] With reference now to drawing Figs. 16a and 16b, an eighth embodiment of a vascular access device 1 is illustrated. In this embodiment, the valve mechanism 8 is comprised of flexible elements or members 18’ that form an intraluminal seal structure, i.e. , within the lumen 6, having a preformed central hole at the distal tip 5 of cannula 2. The flexible elements or members 18’ of the valve mechanism 8 cover the port 7 in the tip 5 in the closed state shown in Fig. 16a when the flexible elements or members 18’ are in a base or relaxed state, due to an elastic bias (e.g., residual compression) in the flexible elements or members 18’, thereby closing the through-hole in the seal. When an intravascular device, such as a catheter C, is advanced through the cannula into contact with the intraluminal seal structure, it engages with and flexes or pivots those elements or members 18’ as shown in Fig. 16b to open the port 7 and allow the catheter to pass through the preformed seal structure into the blood vessel V. The intraluminal seal structure elastically expands to accommodate the catheter C, and simultaneously forms a seal around the catheter. Upon withdrawal of the catheter C, the flexible elements or members 18’ of the seal structure elastically recover to their initial configuration shown in Fig. 16a.

[0048] Referring to Figs. 17a and 17b, a ninth embodiment of a vascular access device 1 is shown. In this case, the valve mechanism 8 comprises a resiliently deformable hole or opening 9 (appreciable only as a slit in Fig. 17a) in the distal tip 5 of the access tube or cannula 2 which forms the access port 7. The port 7 is closed to provide a fluid-tight seal in a base or relaxed state by virtue of an inward bias of the flexible and resiliently deformable material of the distal end 4 of the access tube or cannula 2. In this case, the side walls of the cannula 2 in the distal end region 4 are also resiliently deformable and flexible to accommodate deformation of the device 1 during introduction of a catheter C. When an intra-vascular device, such as a catheter C, is advanced through the lumen 6 of the cannula 2 and makes contact with the inner end face of the tip 5 of the cannula 2, the advancing catheter C forces the resiliently deformable material surrounding the hole or opening 9 apart, which in turn also expands the deformable walls of the cannula 2 to open the port 7, as shown in Fig. 17b. In this way, the catheter C may then pass into the blood vessel V. On removal or withdrawal of the catheter C, the side walls and end face elastically recover to their initial configuration in Fig. 17a. Some possible variations to this embodiment include: incorporating one or more magnetic elements in the facing or mating surfaces of the port 7 to assist closure and sealing of the valve mechanism 8; incorporating a material with strong self-adhesion properties in the facing or mating surfaces of the port 7 to assist closure and sealing of valve mechanism 8; incorporating internal elastic supports (e.g., wires, struts, etc.) to assist in the elastic biasing of gate elements or jaw members 18’; and/or incorporating a cord or draw-line for actuating the tip 5 when operating the valve mechanism 8 between the closed and open states, and especially to assist closure. The deformable distal end region 4 of the cannula 2 may be undersized relative to an intravascular device intended to be advanced through it, such that the distal end 4 of cannula (i.e., its ‘footprint’) in the blood vessel V is reduced when not in use. When in use, this distal end region 4 can be deformed outwards to a size sufficient to accommodate the inserted device.

[0049] Drawing Figs. 18a and 18b show a tenth embodiment of the vascular access device 1 , which includes a valve mechanism 8 having gate members or jaw members 18’ at the distal end 4 of access tube or cannula 2. In this tenth embodiment, the gate members or jaw members 18' are hinged - e.g., via a flexible and resiliently deformable connection or via pivot joint - to a side wall of the access tube or cannula 2. These jaw members 18' are elastically biased such that they are configured to close against each other firmly in a base or relaxed state. In this closed state, the facing or mating surfaces of the gate elements or jaw members 18’ are in firm contact or engagement to create a fluid-tight seal. In this regard, these surfaces may comprise a flexible (e.g., elastomeric) material suitable for creating a contact seal. Again, when an intra-vascular device, such as a catheter C, is advanced through the lumen 6 of the cannula 2 and makes contact with the gate elements or jaw members 18’, the advancing catheter C operates to force those members apart to open the port 7, as shown in Fig. 18b, and so passes into the blood vessel V. Further, in this embodiment, a cord or line 19 can be provided. The cord or line 19 is preferably elastic and exerts a closing force on the gate elements or jaw members 18' when the port 7 is in the open state. In this way, on removal or withdrawal of the catheter C, the gate elements or jaw members 18’ return elastically to their initial position in Fig. 18a. Alternatively, the cord or line 19 may be configured for actuating the gate elements or jaw members 18’ at the tip 5 when operating the valve mechanism 8 between the closed and open states. That is, the cord or line 19 can be designed to be drawn (i.e., pulled under tension) by a user at a proximal end region 3 of the vascular access device to impart or transmit an actuating impulse via the cord or line 19 to the distal end region 4 to operate (i.e., to open or close) the access port 7. The elastic distal end region 4 of the access tube or cannula 2 provides for an improved expansion of the valve mechanism 8 (i.e., in terms of overall achievable expansion for a given cannula size, and magnitude of expansion for a given applied force). Some possible variations to this embodiment include: incorporating one or more magnetic elements in the facing or mating surfaces of the gate members or jaw members 18’ to assist closure and sealing of the valve mechanism 8; incorporating a material with good self-adhesion properties in the facing or mating surfaces of the gate members or jaw members 18’ to assist closure and sealing of the valve mechanism 8; and/or including internal elastic supports (e.g., wires, struts, etc.) to assist in the elastic biasing of gate members or jaw members 18’.

[0050] With reference to Figs. 19a and 19b of the drawings, an eleventh embodiment of a vascular access device 1 is illustrated. In this embodiment, the port 7 comprises an opening at a tip 5 of the access tube or cannula 2 and the valve mechanism or gate mechanism 8 comprises a cover member 18' connected to the side wall of the cannula via an elastically or resiliently flexible hinge element 20. In this way, the hinged cover member 18' is elastically biased so that it is firmly closed against the port 7 in its base state to create a fluid-tight seal. In this regard, the facing or contacting surfaces at the port 7 are preferably formed of a flexible (e.g., elastomeric) material to create a contact seal. When an intravascular device, e.g., catheter C, is advanced through the lumen 6 of the access tube or cannula 2, it contacts and applies a force to an inner side of the cover member 18' which acts to move the cover member 18' and open the port 7 so that the catheter C may then pass through the port 7 into the blood vessel V. As seen in Figs. 19a and 19b, the lumen 6 of the access tube or cannula 2 includes one or more internal surfaces 21 adjacent the opening of the port 7 which is/are angled to guide or direct the catheter C towards and through the port 7, as in earlier embodiments. Upon a withdrawal or removal of the catheter C, the hinged cover member 18' returns elastically due to bias from the hinge element to close the port 7. Some possible variations to this embodiment again include: incorporating one or more magnetic elements in the facing or mating surfaces of the cover member 18' and the tip 5 of the cannula 2 to assist closure and sealing of the gate mechanism 8; incorporating a material with strong self adhesion properties in the facing or mating surfaces of the cover member 18’ and the tip 5 of the cannula 2 to assist closure and sealing of the valve mechanism 8; incorporating internal elastic draw-line to assist in the elastic biasing of the cover member 18’ to the closed state; and/or incorporating an inflatable element at the free end of the hinged cover member 18' to move the cover member 18' when operating the gate mechanism 8 and the port 7 between the closed and open states, and especially to assist closure. [0051] With reference to Figs. 20a and 20b of the drawings, a twelfth embodiment of a vascular access device 1 of this disclosure is illustrated. As with the embodiment shown in Figs. 15a to 15c, in this embodiment the access port 7 comprises a hole or opening in a side wall of a distal end 4 of the access tube or cannula 2 and the valve mechanism 8 comprises a valve member or plate member 18 in the form of an axially slidable cover for the port 7 that is operable between closed and open states. In this embodiment, a hydraulic actuator 22 is operatively connected to the valve member or plate member 18 that is movable relative to the port 7. This hydraulic actuator 22 includes a hydraulic cylinder 23 and a piston 24 movable within the cylinder 23 and connected to the valve member or plate member 18. The cylinder 23 can be pressurised with fluid or evacuated on either respective side of the piston 24 via fluid lines (not shown) in the cannula 2 to move the piston 22 and thereby operate the gate or valve mechanism 8.

[0052] Referring to drawing Figs. 21a and 21 b, a thirteenth embodiment of a vascular access device 1 of this disclosure is illustrated. The configuration of the vascular access device 1 in this case is similar to the embodiment in Fig. 5 in that the gate member 18’ is provided as an end plate or cap 18' forming a closure that substantially fully closes or obscures the opening 9 in the tip 5 of the cannula or access tube 2. As before, the end cap desirably provides a fluid-tight seal. To this end, the contacting or facing surfaces of the plate or cap 18' and the end of the cannula 2 around the opening 9 may be formed of a flexible (e.g., elastomeric) material for creating a contact seal. In this embodiment, however, the axially displaceable rod or stem element 15' which connects to the gate member 18’ is part of a hydraulic actuator 20. A piston head 24 is provided on an end of the rod or stem 15’ and can be pressurised with fluid via a fluid line 25 to advance or move the end plate or gate member 18' to open the port 7 at the end of the cannula 2. Naturally, negative pressure be applied to the piston head 24 to retract the rod or stem element 15' and close the port 7. Further, (or alternatively), a cord or line 19 is provided for actuating the gate member 18' when operating the gate or valve mechanism 8 to the closed state. In this regard, pressure in the hydraulic fluid line 25 is released and the fluid line 25 is vented, and the cord 19 is drawn (i.e., pulled under tension) by a user at a proximal end region 3 of the vascular access device 1 in order to close the access port 7. Alternatively, the cord or draw-line 19 could be elastic and exert a closing force on the end plate or gate member 18' automatically when the port 7 is in the open state. In this way, simply releasing the hydraulic pressure acting in the line 25 against piston head 24 could effect a closure of the port 7 without manually retracting the cord 19. [0053] With reference to Figs. 22a and 22b of the drawings, a fourteenth embodiment of a vascular access device 1 of the disclosure is shown. The gate mechanism or valve mechanism 8 of this embodiment exhibits similarities to the embodiments in Figs. 16a and 16b and Figs. 19a and 19b. For example, the port 7 comprises an opening 9 in a distal end or tip 5 of the access tube or cannula 2 and the valve mechanism or gate mechanism 8 comprises a cover member 18' connected to the side wall of the cannula via an elastically or resiliently flexible hinge element. In this way, the hinged cover member 18' is elastically biased so that it is firmly closed against the port 7 in its base state to create a fluid-tight seal, seen in Fig. 22a. To this end, the facing or contacting surfaces at the port 7 are preferably formed of a flexible (e.g., elastomeric) material to create a contact seal. When an intravascular device, such as a catheter C, is advanced through the lumen 6 of the access tube or cannula 2, it contacts and applies a force to an inner side of the cover member 18' which acts to move the cover member 18' and open the port 7 so that the catheter C may then pass through the port 7 into the blood vessel V, as shown in Fig. 22b. On withdrawal or removal of the catheter C, the hinged cover member 18' then returns due to bias from the resiliently flexible hinge element to close the port 7. A cord or line 19 may also be provided to exert a closing force on the cover member 18' to assist operation of the port 7 to the closed state.

[0054] With reference to Figs. 23a and 23b of the drawings, a fifteenth embodiment of a vascular access device 1 of the disclosure is shown. The gate mechanism or valve mechanism 8 of this embodiment exhibits similarities to the embodiment of Figs. 19a and 19b in the provision of a cover member 18' connected to the side wall of the cannula 2 via an elastically or resiliently flexible hinge element 20. In addition, however, the gate mechanism or valve mechanism 8 comprises a balloon or inflatable membrane structure 26 at a distal tip 5 of the access tube or cannula 2 for actuating the movement of the cover member 18' from the position in Fig. 23a, where the port 7 is in a closed state, to the position in Fig. 23b. When the balloon or membrane structure 26 is inflated, it expands to the position in Fig. 23b and thereby moves the cover member 18' and thus opens the port 7. Deflating the balloon or membrane structure 26 then allow a return of the cover member 18' to the position in Fig. 23a. The balloon or membrane structure 26 may be inflated and deflated by means of a channel or conduit (not shown) provided, for example, in the wall of the cannula 2. [0055] Referring to drawing Figs. 24a and 24b, a gate mechanism or valve mechanism 8 in yet another embodiment of a vascular access device 1 of this disclosure is shown. In this embodiment, the valve member or gate member is comprised of a balloon or an inflatable membrane structure 26 attached to a wall within the lumen 6 at a distal tip 5 of the access tube or cannula 2. When the balloon or membrane structure is inflated, it fully occupies and seals the lumen 6 and thus closes the port 7 at the distal opening 9 of the cannula 2, as shown in Fig. 24b. When vascular access is required, the balloon or membrane structure 26 is deflated such that it lies flat over a partial arc of the luminal wall, leaving the lumen 6 of the cannula 2 free and the access port 7 open for passage of one or more intravascular devices there-through, as shown in Fig. 24a. The balloon or membrane structure may be inflated and deflated by means of a channel or conduit (not shown) provided, for example, in the wall of the cannula 2.

[0056] Referring to Figs. 25a and 25b of the drawings, a seventeenth embodiment of a vascular access device 1 of the disclosure is shown. In this case, valve mechanism 8 comprises a collapsible membrane 27 mounted on a pair of movable struts 28 that are supported on roller bearings 29 located in an annular void 30 around the inner lumen 6 of the cannula 2. In a base state, the struts 28 are biased to deploy the membrane 27 into an expanded condition or position seen in Fig. 25b, where the membrane 27 covers the opening 9 at the distal tip 5 of the cannula 2 to place the port 7 in a closed state. By hydraulically pressurising the annular void 30 in the region between the roller bearings 29, the roller bearings 29 can be driven against the bias of the valve mechanism 8 to collapse or fold the membrane like a “curtain” into the condition or position in Fig. 25a, where the port 7 is then in an open state allowing for the passage of an intravascular device. A pressure line (not shown) for pressurizing the annular void 30 can be provided within the wall of the cannula 2.

[0057] Finally, referring to Fig. 26 of the drawings, a flow diagram is shown to illustrate schematically the steps in a method of introducing a catheter into a blood vessel V of a patient using a vascular access device 1 according to the various embodiments of the disclosure described above with respect to Figs. 1 to 25b. In this regard, the first box i of Fig. 26 represents the step of inserting a vascular access tube 2 percutaneously into a patient, the access tube 2 having a proximal end region 3, a distal end region 4 with a tip 5 for insertion through a wall W of the blood vessel V and a lumen 6 for introducing a catheter there-through into the blood vessel V, wherein a port 7 is provided at the distal end region 4 of the tube 2 for passage of the catheter through it into the blood vessel V. The second box ii represents the optional step of activating a fixation mechanism 10 at the distal end region 4 of the access tube 2 adjacent the tip 5 to secure or fix the distal end region 4 of the cannula or access tube 2 with respect to the blood vessel V. The third box iii then represents the step of operating a mechanism 8 to operate or transition the port 7 from a closed state to an open state to provide fluid communication between the lumen 6 of the vascular access tube or cannula 2 and the blood vessel. The final box iv in Fig. 26 of the drawings represents the step of inserting the catheter from the proximal end region 3 through the lumen 6 of the cannula or access tube 2 for passage through the open port 7 into the blood vessel V.

[0058] Although specific embodiments of the disclosure are illustrated and described herein, it will be appreciated by persons of ordinary skill in the art that a variety of alternative and/or equivalent implementations exist. It should be appreciated that each exemplary embodiment is an example only and is not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those persons skilled in the art with a convenient road map for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents. Generally, this application is intended to cover any adaptations or variations of the specific embodiments discussed herein.

[0059] It will also be appreciated that, unless the context requires otherwise, the terms "comprise", "comprising", "include", "including", "contain", "containing", "have", "having", and any variations thereof, used in this document are intended to be understood in an inclusive (i.e. non-exclusive) sense, such that the process, method, device, apparatus, or system described herein is not limited to the features, integers, parts, elements, or steps recited but may include other features, integers, parts, elements, or steps not expressly listed and/or inherent to such process, method, device, apparatus, or system. Furthermore, the terms "a" and "an" used herein are intended to be understood as meaning one or more unless explicitly stated otherwise. In addition, reference to positional terms, such as “lower” and “upper”, used in the above description are to be taken in context of the embodiments depicted in the figures, and are not to be taken as limiting the disclosure to the literal interpretation of the term but rather as would be understood by a skilled addressee in the appropriate context.

[0060] The terms "proximal" and "distal" are used to refer to the opposite ends of a medical device, such as the vascular access devices disclosed herein. As used herein, the “proximal” end region of the device is the end region near a practitioner during use, while the distal end region is the region at the opposite end of the device remote from the practitioner during use. For example, the proximal end region of a vascular access device is the end closest to the practitioner during the insertion or deployment of the vascular access device. The distal end is the end opposite the proximal end along the longitudinal direction of the medical anchor device. In this case, the tip of the vascular access tube at the distal end region is designed for insertion into the blood vessel.

[0061] As will be appreciated by persons skilled in the art, a direction of bias for a valve mechanism or gate mechanism to its base or relaxed position (i.e. , biasing the port to a closed state or an open state) for a vascular access device according to any one of the various embodiments described herein (and, thus, a respective direction for actuating the valve mechanism or gate mechanism to the other of the said closed or open state) may readily be reversed in each case.

Claims

Claims:

1. A vascular access device, comprising: a vascular access tube comprising a proximal end region, a distal end region having a tip to be inserted into a blood vessel of a patient, and a lumen for introducing a catheter there-through into the blood vessel; wherein a port is provided at the distal end region of the access tube for passage of the catheter there-through into the blood vessel, wherein the port is operable between a closed state and an open state.

2. A device according to claim 1 , wherein, in the open state, the port provides fluid communication between the lumen of the vascular access tube and the blood vessel for passage of the catheter through the port into the blood vessel and, in the closed state, the tip of the access tube is substantially closed.

3. A device according to claim 1 or claim 2, comprising a valve mechanism which includes the port, wherein the valve mechanism is configured for operation of the port between the closed state and the open state.

4. A device according to any one of claims 1 to 3, comprising a cover member that is integrated in the distal end region of the access tube and is movable relative to an opening defining the port to operate the port between the closed state and the open state.

5. A device according to claim 4, wherein the cover member is axially slidable or is rotatable relative to the opening to operate or move the port between the closed and open states, wherein the cover member substantially seals the port in the closed state.

6. A vascular access device, comprising: a vascular access tube comprising a proximal end region, a distal end region having a tip to be inserted into a blood vessel of a patient, and a lumen for introducing a catheter there-through into the blood vessel; and a valve mechanism having a port at the distal end region of the access tube for passage of the catheter there-through into the blood vessel, wherein the valve mechanism is adapted to operate the port between a closed state and an open state for passage of the catheter through the port into the blood vessel.

7. A device according to any one of claims 1 to 6, wherein operation of the port between the closed state and the open state is effected by an actuation, e.g., a manual actuation, at the proximal end region of the vascular access tube.

8. A device according to claim 7, wherein the actuation at the proximal end region of the vascular access tube to operate the port includes a movement in an axial (longitudinal) direction of the access tube, or a rotary movement about the axis, or a combination of axial and rotary movement.

9. A device according to any one of claims 1 to 6, wherein the valve mechanism is configured to operate the port between the closed state and the open state by application of hydraulic pressure, preferably applied at the distal end region of the vascular access tube.

10. A device according to any one of claims 1 to 6, wherein the valve mechanism is configured to move from the closed to the open state by insertion or introduction of an intravascular device through the lumen of the vascular access tube to the distal tip, and wherein the valve mechanism is preferably biased to move to the closed state upon withdrawal or removal of the intravascular device from the lumen of the vascular access tube.

11. A device according to any one of claims 1 to 10, further comprising a closure or cover member configured to substantially close the tip of the vascular access tube in the closed state, wherein the closure or cover preferably comprises part of the valve mechanism and is movable to operate the port between the closed state and the open state.

12. A device according to any one of claims 1 to 11 , wherein the valve mechanism includes an actuation member at the proximal end region of the vascular access tube operably associated or connected with the distal end region of the vascular access tube, wherein the actuation member is adapted for operation by a user to operate the port between the closed state and the open state.

13. A device according to claim 12, wherein the actuation member is movable by a user, preferably slidably and/or rotatably movable, between two positions which respectively define or correspond to the closed state and the open state of the port.

14. A device according to any one of claims 1 to 13, wherein the valve mechanism includes a sleeve or sheath arranged within the lumen of the vascular access tube, preferably in closely fitting relationship, wherein the sleeve or sheath itself, or in combination with the access tube, defines the port, and wherein the sleeve or sheath is movable, and preferably axially slidable, relative to the access tube to operate the port between the closed state and the open state.

15. A device according to any one of claims 1 to 14, further comprising a fixation mechanism operable to secure or fix the tip of the vascular access tube within the blood vessel, wherein the fixation mechanism operates to secure or fix the tip at or adjacent a wall of the blood vessel at a point of insertion of the tip into the blood vessel.

16. A device according to claim 15, wherein the fixation mechanism comprises an intravascular part configured to engage with an inner surface of the wall of the blood vessel through which the tip is inserted to inhibit or prevent withdrawal of the tip of the tube from the blood vessel; and/or wherein the fixation mechanism comprises an extravascular part configured to engage with an outer surface of the wall of the blood vessel tissue to prevent over-insertion of the tube.

17. A vascular access device, comprising: a vascular access tube comprising a proximal end region, a distal end region having a tip to be inserted into a blood vessel of a patient, a lumen along a length of the access tube for introducing a catheter there-through into the blood vessel, and a port at the distal end region of the access tube for passage of the catheter there-through into the blood vessel, and an actuator for operating the port between a closed state for sealing the lumen from the blood vessel and an open state for introducing the catheter into the blood vessel.

18. A device according to claim 17, wherein the vascular access tube comprises a cover member that is movable relative to the port to operate the port between the closed state and the open state port, and wherein the actuator is configured to effect relative movement of the cover member to the port.

19. A device according to claim 18, wherein the actuator is configured to apply an hydraulic pressure to operate the port between the closed state and the open state, preferably at the distal end region of the vascular access tube.

20. A device according to claim 18, wherein the actuator is configured to impart an axial movement or a rotational movement to the cover member to operate the port between the closed state and the open state.

21. A device according to any one of claims 17 to 20, wherein the actuator forms part of a valve mechanism.

22. A method of introducing a catheter into a blood vessel of a patient, the method comprising steps of: inserting a vascular access tube into a patient, the access tube having a proximal end region, a distal end region having a tip to be inserted into a blood vessel of the patient, and a lumen for introducing a catheter there-through into the blood vessel, wherein a port is provided at the distal end region of the tube for passage of the catheter there-through into the blood vessel; and operating a valve mechanism to operate the port from a closed state to an open state to provide fluid communication between the lumen of the vascular access tube and the blood vessel; inserting the catheter from the proximal end region through the lumen of the access tube for passage through the port into the blood vessel.

23. A method according to claim 22, wherein the step of inserting the access tube into the patient, preferably percutaneously, comprises introducing the tip of the access tube through the wall of the blood vessel, preferably over a guidewire, and optionally with the aid of a dilator.

24. A method according to claim 22 or claim 23, wherein the step of operating the valve mechanism to operate the port from the closed state to the open state includes moving an actuation member at the proximal end region of the access tube operably associated or connected with the distal end region of the vascular access tube, wherein the actuation member is movable, preferably slidably or rotatably movable, between two positions which respectively define the closed state and the open state of the port.

25. A method according to any one of claims 22 to 24, further comprising a step of applying suction to the lumen upon operating the port from the closed state to the open state for aspirating any fibrin / thrombus material accumulated at the tip of the access tube prior to inserting the catheter.

26. A method according to any one of claims 22 to 25, wherein the port of the access tube is oriented to face substantially upstream into an oncoming flow of blood in the blood vessel.