Stent Graft and Kit

Abstract

The present invention relates to a stent graft, comprising: a hollow stent graft body having a lumen extending from one end of the stent graft body to the respective other end of the stent graft body, an expandable reservoir provided on an interior of the stent graft body, the expandable reservoir being covered with a separation layer on a side of the expandable reservoir facing the lumen, the expandable reservoir being arranged so as to swell when exposed to blood, the separation layer being arranged to prevent the expandable reservoir from being exposed to blood flowing through the lumen, the separation layer being arranged so that it can selectively expose the expandable reservoir to blood to cause the expandable reservoir to swell.

Claims

1. A stent graft, comprising: a hollow stent graft body having a lumen extending from one end of the stent graft body to the respective other end of the stent graft body, an expandable reservoir provided on an interior of the stent graft body, the expandable reservoir being covered with a separation layer on a side of the expandable reservoir facing the lumen, the expandable reservoir being arranged so as to swell when exposed to blood, the separation layer being arranged to prevent the expandable reservoir from being exposed to blood flowing through the lumen, the separation layer being arranged so that it can selectively expose the expandable reservoir to blood to cause the expandable reservoir to swell.

2. The stent graft according to claim 1, further comprising a semipermeable membrane between the expandable reservoir and the separation layer.

3. The stent graft according to claim 1, the separation layer being arranged to expose the expandable reservoir to blood when exposed to light of a pre-set wavelength.

4. The stent graft according to claim 1, the separation layer being arranged to become permeable to blood when exposed to one or more chemicals.

5. The stent graft according to claim 1, the expandable reservoir having a ring shape surrounding the lumen.

6. The stent graft according to claim 1, the stent graft comprising a plurality of expandable reservoirs, the expandable reservoirs being arranged at different axial positions inside the stent graft body.

7. A kit of parts, comprising the stent graft according to claim 1, and a catheter arranged to cause the separation layer to expose the expandable reservoir to blood, thereby allowing it to swell.

8. The kit of parts according to claim 7, when comprising, the catheter comprising an optical fibre arranged to conduct light from a proximal end of the catheter to a distal end of the catheter to thus exit the catheter, the kit of parts further comprising a light source arranged to emit light of a pre-set wavelength, the optical fibre being arranged to transmit the light to the distal end of the catheter.

9. The kit of parts according to claim 7, the catheter being arranged to release one or more appropriate chemicals selected so as to render the separation layer permeable to allow for the expandable reservoir to swell due to exposure to blood.

10. A stent graft, comprising: a hollow stent graft body having a lumen extending from a first end of the stent graft body to a second end of the stent graft body, an expandable reservoir provided on an interior of the stent graft body, the expandable reservoir designed to swell when exposed to blood, but covered with a separation layer on a side of the expandable reservoir facing the lumen to prevent the expandable reservoir from being exposed to blood flowing through the lumen, the separation layer configured to selectively expose the expandable reservoir to blood.

11. The stent graft according to claim 10, further comprising a semipermeable membrane between the expandable reservoir and the separation layer.

12. The stent graft according to claim 10, wherein the separation layer is arranged to expose the expandable reservoir to blood when exposed to light of a pre-set wavelength.

13. The stent graft according to claim 10, wherein the separation layer is arranged to become permeable to blood when exposed to one or more chemicals.

14. The stent graft according to claim 10, wherein the expandable reservoir includes a ring shape surrounding the lumen.

15. The stent graft according to claim 10, wherein the expandable reservoir comprises a plurality of separate expandable reservoirs arranged at different axial positions on the interior of the stent graft body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 shows schematically a cross-section of a TIPS stent graft according to the first embodiment of the invention.

[0024] FIG. 2 shows a way in which the stent graft according to the embodiment can be used.

[0025] FIG. 3 shows the stent graft of the embodiment of the invention in the expanded state.

DETAILED DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1a) shows a cross-sectional view of a TIPS stent graft 10 according to the present invention. Whilst not shown, one of the longitudinal ends of the stent graft 10 has a bare stent, i.e. that end has no covering material for the stent underlying the stent graft 10.

[0027] The stent graft 10 comprises a stent graft body 12 having a hollow tubular shape. The stent graft body 12, i.e. the body of the TIPS stent, surrounds a lumen 13 by which a fluid can flow through the stent graft 10. On the inside of the stent graft body 12, an expandable reservoir 14 which is covered first by a semipermeable membrane 15 and then by a separation layer 16 is provided, as is shown in more detail in FIG. 1b). The expandable reservoir 14 comprises an osmotically active substance. The separation layer 16 is permeable to blood or some of its components but does not let the material of the expandable reservoir 14 through and therefore keeps that material in place. The semipermeable membrane 15 is permeable to blood or at least some of its components but is impermeable to the material of the expandable reservoir 14. Accordingly, when the separation layer 16 is made permeable to blood, the expandable reservoir 14 will swell.

[0028] The stent graft 10 as shown in FIGS. 1a), b) is implanted in a patient's body. If some time after placement, it is desired to further restrain the diameter of the TIPS stent graft 10, the procedure shown in FIGS. 2a), b) can be performed. A catheter 18 is introduced into the patient's vasculature which comprises an optical fibre (not shown). Through this optical fibre, light 20, such as ultraviolet light, can be shone onto the surface of the separation layer 16 to disintegrate it whilst the semipermeable membrane 15 remains unaffected by the light. Accordingly, the expandable reservoir 14 is exposed to blood flowing through the lumen 13.

[0029] As can be seen in FIG. 3, due to the liquid present in the blood, the reservoir 14 expands, as can be seen from FIG. 3. This expansion reduces the volume available in the lumen 13 for blood to flow through. Accordingly, the stent graft 10 is capable of, if desired, reducing its inner diameter.

[0030] Whilst in the present embodiment, a situation was described where the separation layer 16 is made permeable by light, it is also possible to make this layer permeable by exposing it to appropriate drugs. Further, it is also conceivable to implement a mechanism to mechanically fracture the separation layer 16, for example by having threads implanted into it which can be pulled out and which will, when pulled out, rip apart the separation layer 16. If one wants to use a separation layer 16 which can be made permeable by means of a chemical reaction, one can use a catheter with PTA balloon which is coated with the appropriate chemicals. Once the balloon has been placed inside the stent graft, it can then be expanded to be brought into contact with the separation layer 16. By that contact, the separation layer 16 will be caused to become permeable, so that the expandable reservoir can swell.