Abstract
The invention relates to a vascular access device (10) for implantation onto a vessel wall, the access device comprising an tubular structure (12) to provide an access passage into the vessel via a hole in a vessel wall, a connector arrangement (20; 21) for attaching the tubular structure at said hole in the vessel wall, and a membrane structure (16A; 16B) sufficiently flexible to be collapsed for insertion through said hole and to be expanded to lie at least partially against an inner vessel surface thereby to surround the hole. The membrane structure comprises a membrane aperture (18) to provide a passage from inside the vessel into the tubular structure. The vascular access device further comprises a closing mechanism capable of closing the membrane aperture while the membrane structure is expanded against said inner vessel surface. There is also provided a method of implanting a vascular access device.
Claims
1. A vascular access device for implantation onto a vessel wall, the access device comprising: a tubular structure to provide an access passage into the vessel via a hole in the vessel wall; a connector arrangement for attaching the tubular structure at said hole in the vessel wall; a membrane structure sufficiently flexible to be collapsed for insertion through said hole and to be expanded to lie at least partially against an inner vessel surface thereby to surround the hole, wherein the membrane structure comprises a membrane aperture to provide a passage from inside the vessel into the tubular structure; and a closing mechanism capable of closing the membrane aperture while the membrane structure is expanded against said inner vessel surface.
2. The vascular access device according to claim 1, wherein the closing mechanism comprises a valve arrangement, wherein optionally the valve arrangement comprises one or more flaps.
3. The vascular access device according to claim 1, wherein at least part of the closing mechanism is provided by a portion of the membrane structure.
4. (canceled)
5. The vascular access device according to claim 1, wherein the device further comprises anchoring structures that are also insertable into the vessel through the hole and are expandable and/or articulated to provide structural support to the membrane.
6. The vascular access device according to claim 5, wherein the anchoring structures are feet or a ring structure.
7. The vascular access device according to claim 1, wherein at least part of the connector arrangement is integral with the membrane structure.
8. The vascular access device according to claim 1, wherein at least part of the connector arrangement is integral with the tubular structure.
9. The vascular access device according to claim 1, wherein the connector arrangement comprises a component detachably connectable to the membrane structure.
10. The vascular access device according to claim 1, wherein the connector arrangement provides an annular port to receive an end of the tubular structure.
11. The vascular access device according to claim 1, wherein the tubular structure comprises an end portion whose outer circumference is smaller than the membrane aperture so as to be insertable through the membrane aperture.
12. The vascular access device according to claim 1, wherein the tubular structure comprises an end portion whose outer circumference corresponds sufficiently closely in shape to the membrane aperture so as to be able to maintain the closing mechanism in a flow-permitting configuration.
13. The vascular access device according to claim 1, wherein the tubular structure comprises around at least part of its outer circumference a seating surface of wider circumference and set apart from an end portion of the tubular structure.
14. The vascular access device according to claim 13, wherein at least part of the connector arrangement is provided by the seating surface.
15. The vascular access device according to claim 11, wherein the tubular structure comprises an end portion whose inner circumference has a lumen diameter sufficient to permit flow rates of at least 1 litre per minute at typical vascular driving pressures.
16. The vascular access device according to claim 11, wherein the end portion comprises along its luminal surface regularly repeating inner wall structures.
17. The vascular access device according to claim 1, wherein the tubular structure comprises on its outer surface a plurality of engagement structures spaced apart along the elongate extension of the tubular structure.
18. (canceled)
19. (canceled)
20. The vascular access device according to claim 1. wherein the closing mechanism comprises a shape memory material.
21. The vascular access device according to claim 2, wherein the valve arrangement comprises one or more flaps, and wherein one or more of the flaps comprise mutually engaging profiles at flap-to-flap edges.
22. (canceled)
23. A method of implanting a vascular access device according to claim 1, the method comprising implanting at a hole in a vessel wall a membrane structure, a connector arrangement, and a tubular structure, wherein the membrane structure is provided with a membrane aperture and inserted through a hole in a vessel wall and expanded to lie against an inner surface of the vessel surrounding the hole, and wherein the method comprises aligning the membrane aperture with the hole, and wherein the method further comprises using a closing mechanism to close the membrane aperture while the membrane structure is expanded against the inner vessel surface.
24. The vascular access device according to claim 9, wherein the component is integral with the tubular structure.
Description
DESCRIPTION OF THE FIGURES
[0082] Exemplary embodiments of the invention will now be described with reference to the Figures, in which:
[0083] FIG. 1 is a schematic illustration of an access tube with a connector element;
[0084] FIG. 2 is a schematic illustration of an access tube with an umbrella-type membrane in collapsed condition;
[0085] FIG. 3 is a schematic top view of an umbrella-type membrane in expanded condition;
[0086] FIG. 4 is a schematic illustration of the FIG. 2 access tube with its umbrella-type membrane in expanded condition;
[0087] FIG. 5 is a schematic illustration of an access tube in a step of an exemplary use scenario;
[0088] FIG. 6 is a schematic illustration of the FIG. 5 access tube in a step of an exemplary use scenario;
[0089] FIG. 7 shows a schematic section of an access tube in use;
[0090] FIG. 8 illustrates steps during a removal procedure of the access tube; and
[0091] FIG. 9 shows steps in a sequence of a method of using a vascular access device.
DESCRIPTION
[0092] FIG. 1 shows a vascular access tube 10 constituting a tubular structure. The vascular access tube comprises a tube 12 with an external opening 14 and a connector 20 with a connector end 21. Along the outer surface of the tube 12 a plurality of grooves 24 are provided that extend circumferentially around the tube 12 and are spaced apart along the axial extent of the tube 12. The grooves 24 constitute engagement features that will be described in more detail in relation to FIG. 6 below.
[0093] FIG. 2 shows a variant of the vascular access tube 10, comprising a tube 12 with an external opening 14 and a connector 20 with a connector end 21, and additionally comprising a collapsed umbrella membrane 16A. The umbrella membrane 16A constitutes a membrane structure. It may be integral with the connector 20 and/or releasably attached, or irreversibly attached to the connector 20. The umbrella membrane 16A comprises a central opening (not depicted in FIG. 2) through which the connector end 21 of the connector 20 protrudes, such that the umbrella membrane 16A is disposed around the connector 20.
[0094] FIG. 3 shows a top view of the umbrella membrane 16B in an expanded condition. The umbrella membrane 16B is provided by a patch that has a generally oval circumference and flat profile so as to be able to curve to lie tightly conforming against the inner surface of a blood vessel. Centrally within the umbrella membrane 16B there is provided a closable membrane aperture 18 that is defined by four cuts 162 crossing each other in the manner of circle diameters and separating from one another eight triangular segments providing flaps 164. It can be imagined that each one of the triangular flaps 164 may be bent thereby opening the membrane aperture 18 in the umbrella membrane 16B. The triangular flaps are disposed within an annular coupling structure 160. The coupling structure 160 provides some degree of reinforcement to avoid any of the flaps 164 tearing further than intended by the cuts 162, although it will be understood that depending on the configuration of the flaps a reinforcing effect may not be strong in all embodiments. Radially spaced apart on the coupling structure 160 are several (here: four) alignment points 166 constituting part of a connector arrangement assisting with the alignment of the tubular structure on the membrane aperture 18.
[0095] Although depicted centrally the membrane aperture 18 may be located at a different location of the membrane. It will be understood that a different number of flaps may be provided, for instance a single flap e.g. defined by a C-shaped cut, or two or more flaps. The flaps need not have the same size and/or shape.
[0096] The arrangement of FIG. 3 illustrates a design that allows providing flaps 164 that are integral with the membrane structure 16B. However, the flaps need not be integral and can be of any shape, e.g. could be larger than the membrane aperture 18 and/or at least partially overlapping each other. The edges of the flaps 164 may be provided with mutually engaging features such as a tongue and groove profile or chevron profile to improve the seal between flap edges when closed. The flaps may comprise a shape memory material such as Nitinol, preferably embedded within the flap structure, to facilitate the return of the flaps into a closed position.
[0097] The umbrella membrane 16B comprises a plurality of (here: four) spokes 22. The spokes help to hold the umbrella membrane 16B in an expanded condition and are an example of an anchoring mechanism to provide anchoring to the umbrella membrane against the inside of a vessel by resisting the pulling-out of the membrane. Although four spokes 22 are illustrated in FIG. 3, any number of spokes may be provided. Likewise, a different anchoring structure may be provided, such as a ring or a shape memory structure integrated with the umbrella membrane 16B, or a combination e.g. of a ring with one or more spokes.
[0098] FIG. 4 shows in illustration corresponding to FIG. 2, using the same numerals for similar elements for ease of understanding. In FIG. 4, the umbrella membrane 16B is illustrated in an expanded condition with the connector end 21 inserted through the membrane aperture 18, thereby pushing open the flaps 164 (flaps not depicted in FIG. 4.
[0099] FIGS. 1 to 4 are provided to illustrate components of the vascular access device in assembled form to facilitate the understanding of the components. However, the components may be provided separately, for instance as kit of parts, to be assembled in situ. For instance, the umbrella structure may be inserted and expanded before the tube structure is pushed through the membrane aperture.
[0100] Turning to FIG. 5, this schematically illustrates parts of the access device prior to implantation onto a blood vessel 1 comprising a vessel wall 2 surrounding a vessel lumen 3. The vessel wall 2 comprises an incision 4 or dilated puncture providing an opening 5 from the exterior into the vessel 1 via the vessel wall 2. The umbrella membrane 16A may be implanted in collapsed condition into the blood vessel 1 via the opening 5 and then expanded and positioned within the blood vessel 1. Although not shown in FIG. 1, an introducer tool may be used to access the blood vessel and/or implant the umbrella membrane 16A. When the umbrella membrane is in place inside the blood vessel 1, the connector end 21 of the access channel 10 is pushed through the flaps 164 of the valve arrangement to open the membrane aperture 18.
[0101] Turning to FIG. 6, this shows the umbrella membrane 16B in an expanded condition lying against the inner surface of the vessel wall 2 and surrounding the opening 5 (not shown in FIG. 6). The umbrella membrane 16B is to some extent secured against accidental pulling out from the vessel by way of the anchoring provided by the spokes 22. The tube 12 extends from the blood vessel 1 towards the outside of the skin 6 of a patient, with a length corresponding to a tissue thickness 7. It will be understood that the length of the tube 12 can be adjusted or chosen to suit different level of tissue thickness 7 and may be longer for deeper blood vessels.
[0102] A retainer ring 26 is located around the outer circumference of the tube 12 and engaged in one of the grooves 24. The retainer ring 26 helps to limit the extent to which the tube 12 can be pushed into the patient. This reduces the risk of the tube 12 being dislocated and pressing against the blood vessel 1. An external connector 30 is attached to the external opening 14. The external connector 30 may be any suitable connector such as a multi-ridged connector suitable for connecting tubing to form a fluid channel.
[0103] FIG. 7 illustrates a section of the vascular access device 10 inserted into a blood vessel 1. For conciseness, the same numerals are used in FIG. 7 as for corresponding elements in the preceding Figures. The umbrella membrane 16B is in an expanded condition lying against the inner surface of the vessel wall 2 such that the flaps 164 of the membrane aperture 18 align with the opening 5 in the vessel wall 2. The connector end 21 of the connector 20 protrudes through the membrane 18 to maintain the flaps 164 in an open position. The connector 20 comprises an annular collar 28 adjacent the connector end 21 which has a wider cross-section than the connector end 21 and so provides a seating surface that prevents insertion into the vessel 1. The connector 20 may be fixed to the membrane aperture 16B by way of a cooperating engagement structure, such as a bayonet connection or friction fit. For instance, the connector end 21 may be dimensioned to tightly fit into the annular coupling structure 160 (not shown in FIG. 7, see FIG. 3) to provide a practically fluid-tight seal. The seating surface 28 and the spokes 22 provide locator structures that help to keep the umbrella membrane 16B and the tube 12 in place and to maintain their position relative to one another. The seating surface 28 may be designed to cooperate with the alignment structures 166 to ensure the correct location of the tubular structure relative to the membrane aperture. The seating surface 28 may comprise or consist of pliable material, for instance in the form of a surface configuration such as a lining. The pliable material may have flexibility sufficient to allow it to conform to the curvature of a vessel wall. The alignment structure may comprise a lip on the seating surface 28. The lip may be integral with the seating surface 28 and comprise or consist of a flexible material able to conform to the shape and wall thickness of the hole in the vessel wall.
[0104] As illustrated in FIG. 7, the tube 12 may be provided as a multicomponent wall structure with an inner duct and an outer sleeve. The inner duct may be designed with fluid flow properties in mind. The outer sleeve may be designed with practical aspects of an implant, such as locating features and/or retention features. For instance, the outer sleeve could be overmoulded over an inner duct. However, this need not be the case and in embodiments the tube 12 comprises a single-component wall.
[0105] The connector end 21 may be provided with one or more alignment features to align with the corresponding alignment points 166 on the umbrella membrane (see FIG. 3). The coupling between the tube and the umbrella membrane may comprise a magnetic mechanism. The coupling between the tube and the umbrella membrane may comprise an adhesive. A structure similar to the access device 10 illustrated in FIG. 7 may be provided in pre-assembled form, to be implanted with the help of a delivery tool or an introducer device. For instance, a delivery tool may comprise a sleeve in which the umbrella membrane is held in collapsed form and in which the collar providing a seating surface is collapsed. When the vascular access device is inserted through the opening 5 and aligned appropriately across the vessel wall 3, the delivery tool can in that case be removed to let the umbrella membrane expand within the vessel wall and to let the seating surface expand outside the vessel wall.
[0106] FIG. 8 shows a sequence of three steps during removal of the vascular access device 10 e.g. after conclusion of an intervention. In the top illustration 8A, the tube 12 is located in the opening 5 and the connector end 21 maintains the flaps 164 of the membrane aperture in an open condition. In the middle illustration 8B, the tube 12 has been removed and so the flaps 164 are urged into a closed condition in which they keep the opening 5 in the vessel closed and practically fluid tight. The flaps 14 may comprise a shape memory structure to help ensuring that the flaps are sufficiently flexible to properly close even after prolonged periods of time during which they may have been exposed to the body's immune system. As depicted in illustration 8B, the removal of the tube 12 results in a sealing of the vessel in a manner that is practically fluid tight such that the vessel can continue to supply blood, without a requirement to suture or clamp the vessel at the stage of removing the tube. In embodiments in which the valve arrangement is provided separately from the umbrella membrane, it may be necessary to close the membrane aperture with a separate sealing element, such as a suitable foam or cap. The valve arrangement illustrated in FIGS. 3 and 8B is integral with the membrane structure and thereby avoids a need for introducing a separate vascular closure device after removal of the tubular structure.
[0107] At the stage shown in the middle illustration 8B, a new tube 12 or similar device could be reinserted into the membrane aperture. This can be achieved without requiring a new puncture in the vessel wall.
[0108] The last illustration 8C of FIG. 8 shows the conclusion of an intervention, where the flaps may be provided with an additional seal, for instance a less reversible seal mechanism, e.g. using sutures 30 or adhesive material 32. The umbrella membrane 16B may be left in place after conclusion of a procedure. For instance, the umbrella membrane may consist of a biocompatible material to be endotheliased (overgrown with vessel-lining tissue).
[0109] FIG. 9 shows steps of using the vascular access device in a method 50 of accessing a vessel such as the femoral artery or the axillary artery. The method 50 comprises a step 52 of providing a membrane structure with a membrane aperture. The membrane aperture may comprise a valve arrangement to close the membrane aperture. The method may comprise a step 54 of inserting into the vessel, via a hole such as an incision or puncture made in a vessel wall, the membrane structure in an at least partially collapsed condition. In another step 56, the membrane structure is allowed to expand so as to lie against an inner wall of the vessel, surrounding the hole. In another step 58, a membrane aperture is aligned with the hole. Step 58 may precede or may be executed concurrently with step 56. In another step 60, a connector arrangement is provided. The connector arrangement or part of it may be pre-manufactured and/or be integral with the membrane structure. Preferably, the connector arrangement surrounds at least part of the membrane aperture. In another step 62, a tubular structure is provided and attached to the membrane structure via the connector arrangement. The tubular structure may comprise the connector arrangement or a part thereof. In another step 64, an end of the tubular structure is pushed through the membrane aperture to open a valve mechanism. For instance, the end of the tubular structure may push open a flap valve arrangement. Thereby, the valve mechanism is actuated by way of carrying out the attachment of the tubular structure. In another step 66, a seating surface of the tubular structure is abutted against a part of the connector arrangement or the vessel wall to prevent further insertion of the tubular structure into the vessel. In another step 68, an outer end of the tubular structure is located on a patient's skin. It will be understood that some of the steps may be optional, may be carried out in a different order and/concurrently, and that some steps may be carried out implicitly by way of carrying out other steps. For instance, the connector end of the tubular structure may be designed such that the flaps of the valve arrangement are opened and just before the tubular structure connects in a fluid tight manner with a coupling feature of the membrane aperture.
[0110] The tubular structure of the access device can be used to introduce fluids directly into the blood vessel. For instance, the access device can be used to introduce oxygenated blood towards a target organ. Likewise, the access device can be used as an access channel for clinical tools.
[0111] Removal of the vascular access device may include a step of detaching the tubular structure from the membrane structure. The removal of the tubular structure may allow the valve arrangement to close thereby to close the membrane aperture. In another step, the valve arrangement may be sealed further using a cap, foam or sutures. The membrane structure may remain in place.
[0112] The method may be used in a training environment, for instance using phantoms or training material, without providing an actual treatment of a human or animal organism.
[0113] The vascular access device combines the ability to provide an access channel into a blood vessel with the ability to seal the blood vessel using a component of the access device. Hitherto, access into a vessel required at least two separate tools, namely a cannula or catheter to be inserted via a puncture in a vessel wall, and a vascular closure device to seal the puncture after a procedure. The present access device integrates a closure functionality with the vascular access channel. This reduces the need for introducing and aligning a further tool upon conclusion of a clinical procedure.
