CATHETER FOR INTRAVASCULAR BLOOD PUMP

Abstract

An intravascular blood pump (P) comprises a catheter (5) and a pumping device (1) attached to a distal end (15) of the catheter (5). The blood pump (P) is advanced through a patient's blood vessel by means of the catheter (5). The catheter (5) has an elongate tubular body (10) and a porous three-dimensional structure (6) provided on at least a portion of the outer surface (8) of the catheter body (10) to promote adsorption of proteins and formation of an autologous graft (7) to prevent the catheter (5) from growing into the inner wall of the blood vessel. The porous three-dimensional structure (6) may be formed as a textile sleeve (6), preferably made of a warp knitted fabric.

Claims

1. A catheter for an intravascular blood pump for percutaneous insertion into a patient's blood vessel, the catheter having an elongate tubular body which extends between a proximal end and a distal end and has an outer surface, the catheter including a porous three-dimensional structure on at least a portion of the outer surface.

2. The catheter of claim 1, wherein the porous three-dimensional structure is formed by a sleeve arranged on the outer surface of the tubular body.

3. The catheter of claim 2, wherein the sleeve comprises a textile material.

4. The catheter of claim 2, wherein the sleeve comprises at least one of a knitted fabric, a knotted fabric, a woven fabric or a nonwoven.

5. The catheter of claim 3, wherein the sleeve comprises a knitted fabric formed by warp knitting, preferably formed as 1×1 constructed knits or 2×1 constructed knits.

6. The catheter of claim 2, to wherein the sleeve comprises a knitted fabric including multi-filaments, each multi-filament preferably comprising 3 to 100 filaments, preferably 15 to 30 filaments, more preferably 24 filaments, wherein the multi filaments preferably have a diameter in a range of 0.5 μm to 10 μm, more preferably 1.7 μm to 5 μm and most preferably 2 μm to 4 μm.

7. The catheter of claim 2, wherein the sleeve has an elongate tubular body having a proximal end and a distal end and is attached to the tubular body of the catheter at least at the proximal end and the distal end of the sleeve, preferably in a glue-free manner, preferably only at the proximal end and the distal end of the sleeve.

8. The catheter of claim 2, wherein the sleeve is solvent-welded to the tubular body of the catheter.

9. The catheter of claim 2, wherein the sleeve is tightly fitted on the outer surface of the tubular body of the catheter.

10. The catheter of claim 2, wherein the sleeve is loosely fitted on the outer surface of the tubular body of the catheter such that a clearance exists between the tubular body and an inner surface of the sleeve.

11. The catheter of claim 2, wherein the sleeve is stiffer in a radial direction as compared to an axial direction.

12. The catheter of claim 1, wherein the porous three-dimensional structure is formed from or comprises a foam or sponge-like structure.

13. The catheter of claim 1, wherein the porous three-dimensional structure is integrally formed on an outer surface of the tubular body of the catheter.

14. The catheter of claim 1, wherein the porous three-dimensional structure is directly formed onto the tubular body of the catheter, preferably by electrospinning or spraying.

15. The catheter of claim 1, wherein the porous three-dimensional structure comprises melt-spun filaments, the melt-spun filaments preferably having a diameter in a range of 1 μm to 100 μm, more preferably 2 μm to 30 μm and most preferably 10 μm to 20 μm.

16. The catheter of claim 1, wherein the porous three-dimensional structure comprises a single layer or comprises more than one layer which are preferably of different configuration.

17. The catheter of claim 16, wherein the porous three-dimensional structure comprises a first layer having a foam-like or sponge-like structure and a second layer in the form of a textile sleeve, the second layer preferably surrounding the first layer.

18. The catheter of claim 1, wherein the porous three-dimensional structure defines a plurality of first apertures and a plurality of second apertures, the first and second apertures being different in size.

19. The catheter of claim 1, wherein the porous three-dimensional structure comprises a non-absorbable material.

20. The catheter of claim 1, wherein the porous three-dimensional structure comprises a radiopaque material.

21. The catheter of claim 1, wherein the porous three-dimensional structure comprises at least one of polyethylene, polypropylene, polyamide, polyether sulfone, polyethylene terephthalate, polyurethane or natural protein fibers, preferably silk fibers.

22. The catheter of claim 1, wherein the porous three-dimensional structure is configured to promote adsorption of fibrinogen, the three-dimensional structure preferably including a plurality of apertures and a plurality of webs permitting adsorption of fibrinogen in a radial inward direction.

23. The catheter of claim 1, wherein the porous three-dimensional structure has a thickness of at least 20 μm, preferably at least 30 μm.

24. A catheter for an intravascular blood pump for percutaneous insertion into a patient's blood vessel, the catheter having an elongate tubular body which extends between a proximal end and a distal end and has an outer surface, wherein at least a portion of the outer surface is configured to promote adsorption of proteins, preferably blood proteins, most preferably fibrinogen.

25. The catheter of claim 1 wherein the catheter is combined with a pumping device to form an intravascular blood pump for percutaneous insertion into a patient's blood vessel.

26. The catheter of claim 24 wherein the catheter is combined with a pumping device to form an intravascular blood pump for percutaneous insertion into a patient's blood vessel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The foregoing summary, as well as the following detailed description of preferred embodiments, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, reference is made to the drawings. The scope of the disclosure is not limited, however, to the specific embodiments disclosed in the drawings. In the drawings:

[0029] FIGS. 1a and 1b schematically show an intravascular blood pump inserted into a patient's heart via different types of access.

[0030] FIG. 2 shows a cross-section of the catheter of the blood pump of FIG. 1 with the sleeve.

[0031] FIG. 3 shows an embodiment of a knit pattern for the sleeve.

[0032] FIG. 4 shows another embodiment of a knit pattern for the sleeve.

[0033] FIG. 5 shows an alternative embodiment for a porous three-dimensional structure.

[0034] FIG. 6 shows a further alternative embodiment for a porous three-dimensional structure.

[0035] FIG. 7 shows the catheter of FIG. 2 with a bi-layered porous three-dimensional structure.

DETAILED DESCRIPTION

[0036] In FIGS. 1a and 1b is illustrated an intravascular blood pump P inserted into a patient's heart H. More specifically, the blood pump P comprises a pumping device 1 attached to a catheter 5 by means of which the pumping device 1 is inserted into the left ventricle LV of the patient's heart H to pump blood from the left ventricle LV into the aorta AO. The shown application is only an exemplary application, and the blood pump P of the present invention is not limited to this application. For instance, reverse applications for the right ventricle RV may be envisioned. The blood pump P is percutaneously inserted e.g. via a femoral access and is advanced through the aorta AO into the heart H (see FIG. 1a). Alternatively, the blood pump P may be percutaneously inserted via an axillary access and advanced via a subclavian artery SA and through the aorta AO into the heart H (see FIG. 1b). The blood pump P is placed such that a blood flow outlet 2 is disposed outside the patient's heart H in the aorta AO, while a blood flow inlet 3 which is in flow communication with a flow cannula 4 is disposed inside the left ventricle LV. An impeller (not shown) is provided in the pumping device 1 to cause the blood flow from the blood flow inlet 3 to the blood flow outlet 2, and rotation of the impeller is caused by an electric motor (not shown) disposed in the pumping device 1.

[0037] The intravascular blood pump P is advanced into the patient's heart by means of the catheter 5, wherein the pumping device 1 is attached to a distal end 15 of the catheter 5 opposite a proximal end 16 of the catheter 5. As schematically illustrated in FIG. 1, the catheter 5 may contact the inner wall of the aorta AO, either during insertion or during operation or most likely both. This may cause irritation or injury of the vessel (triggered by the surface topology and a foreign material) wall and prompts overgrowth of the catheter 5 with bodily tissue. Proteins and other cells contained in the blood will adhere to the outer surface of the catheter 5. In particular, initially proteins and cells will adhere to the outer surface of the catheter 5. Therefore, known catheters tend to grow in the tissue of the vessel, which makes it difficult to remove the blood pump P from the patient's body. This will occur particularly in long-term application, where the blood pump P is in operation for several weeks or months. Removal of the ingrown catheter may cause injuries to the blood vessel.

[0038] In order to reduce or avoid tissue ingrowth or overgrowth, a porous three-dimensional structure in the form of a textile sleeve 6 is provided along at least a portion of the catheter 5, in particular in a portion which tends to contact the inner vessel wall. Although the sleeve 6 induces adhesion of fibrinogen and could be considered to promote tissue ingrowth, it has been found that the opposite occurs due to formation of an autograft 7 (see FIG. 2) on the sleeve 6, which slides along the inner vessel wall as will be explained in more detail below.

[0039] Referring now to FIG. 2, a cross-section of the catheter 5 with the sleeve 6 mounted thereon is schematically illustrated. The catheter 5 has a tubular body 10 with an outer surface 8 and a lumen 9. The sleeve 6 has a tubular body 17 with a distal end 11 and a proximal end 12 and is attached to the body 10 of the catheter 5 by a suitable attachment technique, in particular solvent welding, which does not require the use of additional adhesive. As indicated in FIG. 2 at reference numerals 13 and 14, the sleeve 6 is attached to the catheter body 10 only at its distal end 11 and proximal end 12. Thus, the major part of the sleeve 6 between its ends 11, 12 is not attached to the outer surface 8 of the catheter body 10, such that the mechanical characteristics of the catheter 5 are substantially not affected by the sleeve 6. Further, it will be appreciated, while the sleeve 6 is shown to be formed of a single layer, it may comprise more than one layer. The layers may be identical or different, e.g. with respect to the size of the apertures formed by the knitted fabric described below and/or with respect to the layer materials.

[0040] The textile sleeve 6 may be made of a warp knitted fabric. A warp knitted fabric has good elasticity properties and provides a support structure with apertures to promote adsorption of the autograft 7. Other textile materials, such as knotted fabrics, woven fabrics, non-woven materials or a combination thereof may be used if they are suitable for inducing formation and for supporting the autograft. Examples of known warp knitted fabrics, which have been found to be particularly suitable for the sleeve 6, are schematically shown in FIGS. 3 and 4. FIG. 3 shows a knitted fabric 20 as 1×1 constructed knits (also known as tricot). FIG. 4 shows a knitted fabric 30 as 2×1 constructed knits. In order to visualize the knitting patterns, a distinct thread 21 is marked in FIG. 3 among the threads 22. Apertures 23, 24 of different size are formed between the threads 21, 22 to promote adsorption of fibrinogen and further adhesion of blood cells to form the autograft 7. The same applies for the threads 31, 32 and the apertures 33, 34 of the knitted fabric 30 shown in FIG. 4. Preferably, the threads 21, 22, 31, 32 are formed by multi-filaments to enhance the three-dimensional structure of the sleeve 6.

[0041] The autograft 7 grows into the three-dimensional structure provided by the sleeve 6, in particular the warp knitted fabrics 20, 30 comprising multi-filaments as explained above. Since the autograft 7 is stably supported by the sleeve 6, it does not crumble or loosen but provides a slippery autologous coating which prevents adhesion of the catheter 5 to the inner vessel wall. The autograft 7 grows into the sleeve 6, such that the overall diameter of the catheter 5 substantially does not increase after initial formation of the autograft 7. The autograft 7 covers the sleeve 6 such that the catheter 5 will not be encapsulated in the region of the sleeve 6 as a foreign object and can be easily removed without causing trauma to the blood vessel. Furthermore, if trauma is caused initially upon insertion of the blood pump P into the patient, healing may start even during operation of the blood pump P with the catheter 5 in place in the blood vessel.

[0042] Thus, the intentional and desired adsorption of proteins and other cells on the sleeve 6 does not lead to ingrowth of the catheter 5 into the vessel wall, but has the unexpected effect that an autologous coating is formed which allows the catheter to slide freely inside the blood vessel and prevents ingrowth of the catheter 5. The unexpected effect can be described by the different dynamics. That means, while the formation of the autograft starts immediately, as soon as the porous structure is immersed in blood, the catheter overgrowth takes weeks. Thus, as soon as the autograft is present (typically within days), the stimulus for overgrowth from the vessel wall onto the adjacent catheter is stopped and overgrowth does not occur.

[0043] FIGS. 5 and 6 schematically show further alternative embodiments for a porous three-dimensional structure which may be applied to a catheter instead of or possibly in addition to the aforementioned sleeve 6. Formation of the autograft occurs in the same way as explained above for the sleeve 6. Referring to FIG. 5, the porous three-dimensional structure 40 may be formed by electrospinning in one or more layers and may comprise a plurality of filaments 41 to form apertures 42 to permit formation of the autograft 7 as explained above. The filaments 41 and thus the apertures 42 may be arranged irregularly in desired dimensions. Electrospinning allows for manufacturing of the porous structure 40 directly onto the catheter 5. Likewise, a foam-like or sponge-like structure 50 having apertures 51 as shown in FIG. 6 may be formed directly on the catheter 5.

[0044] FIG. 7 shows the catheter 5 of FIG. 2 with a multi-layered three-dimensional structure on its outer surface 8. In this embodiment, the multi-layered structure has two porous layers 6a and 6b. The two layers 6a, 6b may be different. For instance, the inner layer 6a may be formed as a foam or by electrospinning of filaments directly on the outer surface 8 and the outer layer 6b may be formed as a textile sleeve.