Catheter for intravascular blood pump
The catheter with a porous three-dimensional structure addresses internal tissue growth by forming an autograft, facilitating easy removal and reducing vascular trauma through a self-coating mechanism.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- ABIOMED EUROPE GMBH
- Filing Date
- 2024-07-10
- Publication Date
- 2026-06-09
AI Technical Summary
Intravascular blood pumps face challenges with internal tissue growth and encapsulation, making long-term use difficult due to the body's natural reaction to foreign objects, leading to potential trauma during removal.
A catheter with a porous three-dimensional structure on its outer surface promotes the adsorption of proteins like fibrinogen, forming an autograft that acts as a slippery coating, preventing tissue growth and allowing easy removal.
The autograft formed on the catheter reduces tissue irritation, enabling easy removal without vascular trauma, even in long-term use, by promoting a self-coating that prevents abnormal proliferation.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to an intravascular blood pump that is percutaneously inserted into a patient's blood vessel and particularly enters the patient's heart. More specifically, the present invention relates to a catheter for an intravascular blood pump that reduces or prevents penetration into vascular tissue.
Background Art
[0002] An intravascular blood pump designed to be percutaneously inserted into a patient's blood vessel, such as the femoral artery or vein or the axillary artery or vein, can enter the patient's heart so as to function as a left ventricular assist device or a right ventricular assist device. Therefore, the blood pump is sometimes referred to as an intracardiac blood pump. The intravascular blood pump typically includes a catheter and a pump device attached to the distal end of the catheter. The catheter may have an elongated tubular body and may house supply lines such as a power transmission line and a purge line. The pump device may include an impeller that rotates during operation of the blood pump to send blood from the blood flow inlet of the blood pump to the blood flow outlet, for example, through a flow cannula. Throughout the present disclosure, the term "distal" refers to the direction away from the user and toward the heart, and the term "proximal" refers to the direction toward the user.
[0003] The intravascular blood pump can be used for short-term use of several hours or days, or long-term use extending over several weeks or months. The intravascular blood pump can usually be used as a bridge to recovery. That is, it means that after the heart has recovered sufficiently and no longer needs to be supported by the blood pump, the blood pump is removed from the patient. However, especially in long-term use, it may be difficult to remove the blood pump because the blood pump may be encapsulated in vascular tissue. Encapsulation of foreign bodies due to abnormal growth (and, in some cases, internal growth) of tissue is a natural reaction of the human body to foreign bodies and forms a protective barrier between the body and the foreign bodies in the body. Generally, the material and surface of the foreign body, the shape of the foreign body, the mechanical stimulation caused by the foreign body, etc. induce encapsulation of the foreign body by the tissue.
[0004] In intravascular blood pumps, the catheter extending through the blood vessels towards the heart may be treated as a foreign object by the patient's body and, therefore, may be exposed to internal tissue growth or abnormal proliferation due to its proximity to the blood vessel wall. In particular, mechanical stimulation of the blood vessel wall caused by contact with the catheter can promote internal tissue growth. Internal tissue growth is a significant problem in long-term use, such as when the blood pump is in operation for more than 30 days. Removing the blood pump may require considerable force (e.g., up to 50N), which can cause severe trauma or damage to the blood vessel, potentially leading to the release of granular material and causing infarction.
[0005] Various attempts have been made to reduce or avoid catheter intrusion into blood vessels. However, testing is difficult because superficially different types of catheters exhibit different responses to internal tissue growth or abnormal proliferation. Internal tissue growth or abnormal proliferation begins inside the vascular lumen and on the implant side, with fibrinogen adsorbing to the outer surface of the catheter first. Subsequently, platelets and red blood cells (RBCs) adhere to the fibrinogen layer. Finally, a thin sleeve containing fibrin forms on the outer surface of the catheter.
[0006] To avoid the formation of such sleeves, catheters typically have a smooth surface and are made of materials such as extruded polyurethane (PU). However, such sleeves can still form and adhere to the vessel wall or crumple on the smooth polyurethane surface. If the sleeve loosens, it can detach, at least partially, and cause infarction. To avoid fibrinogen adsorption, organic or inorganic additives (such as silver) may be added to the polyurethane. Similarly, antithrombotic, hydrophilic, or hydrophobic coatings may be applied. Nevertheless, tissue growth within the catheter remains a problem and a significant barrier to the long-term use of intravascular blood pumps. [Overview of the Initiative] [Problems that the invention aims to solve]
[0007] Therefore, an object of the present invention is to provide an intravascular blood pump, more specifically a catheter for an intravascular blood pump, that enables easy removal of the blood pump from the patient after a certain period of time, particularly in long-term use, by reducing or avoiding internal tissue growth. [Means for solving the problem]
[0008] This objective is achieved by a catheter having the features described in the independent claim, in accordance with the present invention. Preferred embodiments and further developments of the present invention are specified in the dependent claims.
[0009] According to one aspect of the present invention, a catheter for an intravascular blood pump that is inserted percutaneously into a patient's blood vessel is provided. According to another aspect, an intravascular blood pump that is inserted percutaneously into a patient's blood vessel is provided, the intravascular blood pump comprising a pump device and a catheter. In both aspects, the catheter comprises an elongated tubular body that extends between a proximal and distal end and has an outer surface. According to the present invention, at least a portion of the outer surface of the catheter is configured to promote the adsorption of proteins, particularly blood proteins, most preferably fibrinogen.
[0010] In one embodiment, the catheter includes a porous three-dimensional structure on at least a portion of its outer surface. The structure is porous, i.e., it has a plurality of openings that allow for the adsorption of blood proteins and other cells. The structure is three-dimensional, i.e., it has a particularly small radial dimension (thickness), as will be described in more detail below.
[0011] Surprisingly, porous three-dimensional structures can reduce or prevent internal tissue growth. While the initial attempt was to use porous structures to promote internal tissue growth in order to fix the catheter in place within a blood vessel, it was found that porous structures could reduce and even prevent internal tissue growth. More specifically, according to the present invention, it is desirable that the porous three-dimensional structure promotes the formation of autografts (referred to as "autografts"). These autografts form a slippery surface, preventing abnormal proliferation or internal growth of tissue (particularly the tissue of the inner wall of the blood vessel where the catheter is positioned during the operation of the blood pump). In other words, the patient's body generates its own coating, or autocoating, on the catheter in the areas of the porous structure.
[0012] Therefore, the basis of autografts can be the adsorption of proteins, particularly fibrinogen. Thus, more generally, in contrast to known catheters designed to avoid internal tissue growth, a catheter for intravascular blood pumps is provided which has a porous three-dimensional structure on at least a portion of its outer surface capable of adsorbing proteins, such as fibrinogen and / or other proteins. After fibrinogen adsorption, platelets and red blood cells may adhere to the fibrinogen layer. Further cells and / or fibrinogen, such as endomysial cells, may adhere to form a stable and homogeneous autograft. As a result, after the formation of the autograft, which is a self-coating as already described above, the autograft is positioned to overlap each portion of the outer surface of the catheter that supports the porous three-dimensional structure. Thus, the outer surface of the autograft forms the outermost surface of the entire assembly, which includes the catheter, the porous three-dimensional structure, and the autograft.
[0013] The autograft is supported and held in place by a porous three-dimensional structure. The autograft is slippery, allowing the catheter to slide within the blood vessel without damaging or adhering to the vascular wall. The autograft formed on the porous structure reduces tissue irritation, thereby reducing the body's natural response to encapsulate foreign objects, preventing the catheter from being covered by abnormal tissue growth, and allowing for easy removal of the catheter without causing trauma to the blood vessel, even during long-term use, such as approximately 3-6 months. Even if trauma to the blood vessel occurs due to initial mechanical irritation during catheter insertion and advancement, these injuries may heal once the catheter is in place. To avoid mechanical irritation or internal growth of the blood vessel, the porous structure can be provided along the entire length of the catheter or only in the portion of the catheter body that is positioned within a large blood vessel during blood pump operation.
[0014] In a preferred embodiment, the porous three-dimensional structure is comprised of a sleeve positioned on the outer surface of the catheter body. The sleeve may be made of or formed from a fabric material such as knitted fabric, knotted fabric, woven fabric, nonwoven fabric, or a combination thereof.
[0015] In particular, the sleeve can be constructed from a knitted fabric, preferably made by warp knitting. Appropriate warp knitting techniques, such as 1x1 knit (also known as tricot) or 2x1 knit, can be used. Such warp-knitted fabrics have excellent elasticity and can follow the movement and bending of the catheter without significantly affecting the mechanical properties of the catheter body. Furthermore, the mesh structure of the fabric material (especially the knitted fabric) provides a support structure with openings and threads for attaching proteins and cells to form the aforementioned autograft.
[0016] The knitted fabric may contain multifilaments, each of which preferably consists of 3 to 100 filaments, preferably 15 to 30 filaments, and more preferably 24 filaments. The fabric material for the sleeve may be manufactured by a melt spinning process, which makes it possible to produce very fine filaments, for example, with a diameter of about 1 μm to 100 μm, preferably 2 μm to 30 μm, and more preferably 10 μm to 20 μm.
[0017] Regarding fabric materials, for example, in the case of warp-knitted fabrics, the linear density of the fibers, yarns, or threads is defined as the mass in grams per 1000 meters and is measured in units of "tex". An example of PET fabric with 24 filaments per multifilament is PET78dtex / 24f. Other examples of fabric materials suitable for sleeves include polyamide in the range of 17dtex / 3f to 110dtex / 34f, or PES in the range of 33dtex / 24f to 180dtex / 88f.
[0018] In addition to the examples above, it is possible to use multifilaments consisting of very fine filaments with diameters of, for example, about 0.5 μm to 10 μm, preferably 1.7 μm to 5 μm, and more preferably 2 μm to 4 μm. These filaments can be obtained, for example, by a so-called sea-island spinning process. The number of filaments per yarn needs to be adjusted according to the desired yarn diameter.
[0019] The sleeve may comprise an elongated tubular body having a proximal and distal end. The sleeve may be attached to the tubular body of the catheter at least at the proximal and distal ends of the sleeve. It is understood that the sleeve may also be attached to the catheter body at additional positions along the longitudinal portion of the sleeve body or along the entire length of the sleeve. However, if the sleeve is secured only at both ends, the mechanical properties of the catheter are not substantially affected. It is advantageous that the sleeve be attached to the catheter body in an adhesive-free manner, i.e., without using additional adhesives that may cause malfunctions during use. For example, the sleeve may be attached to the catheter body by solvent bonding, in which case a solvent such as tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), or dimethylformamide (DMF) is used to etch the catheter body without affecting the sleeve material. The sleeve is then firmly bonded to the catheter body.
[0020] The sleeve fits snugly against the outer surface of the tubular body. In other words, the inner diameter of the sleeve may be substantially equal to, or only slightly larger than, the outer diameter of the catheter body. To avoid the accumulation of tissue or blood clots within the sleeve, i.e., between the sleeve and the catheter body, a snug fit of the sleeve against the catheter body is sometimes preferable to a loose fit. When snug, the sleeve may be more rigid radially than axially. In particular, the sleeve may be flexible axially, especially with respect to axial stretching and axial compression. More specifically, the sleeve may be axially stretchable and axially compressible, so that it can be positioned snugly against the catheter while allowing the catheter to bend without wrinkling.
[0021] However, if requested, the sleeve may be fitted loosely, meaning the inner diameter of the sleeve may be larger than the outer diameter of the catheter body. If the sleeve is fitted loosely, allowing a gap to exist between the outer surface of the catheter body and the inner surface of the sleeve, the autograft may at least partially encapsulate the sleeve. In other words, the autograft can extend radially through the sleeve, or radially from both the radial outer surface and the radial inner surface of the sleeve, thereby allowing it to contact the outer surface of the tubular body of the catheter.
[0022] The porous structure is preferably composed of or formed from a non-absorbable material. The porous structure functions as a support structure or scaffold for the autograft. Therefore, it is preferable that the porous structure is stable and not absorbed over time and during the operation of the blood pump. Regardless of its absorption properties, the porous structure may be made of a radiopaque material. This makes it easier to observe the correct placement of the catheter, in particular the correct placement of the porous structure. More specifically, it is possible to observe whether a porous structure that may extend along only a portion of the longitudinal part of the catheter is correctly placed in the critical area of the blood vessel where abnormal tissue growth is most likely to occur. For example, some of the threads of a fabric material may be made of a radiopaque material so that they function as radiopaque markers.
[0023] Suitable materials for porous structures include polyethylene (PE), polypropylene (PP), polyamide (PA), polyethersulfone (PES), polyethylene terephthalate (PET), polyurethane (PU), and natural protein fibers such as silk. The fabric material of the sleeve may consist of filaments made from one or more of the above materials. The sleeve may consist of a single material or a combination of materials. For example, the warp and weft threads of the fabric material may be made of different materials.
[0024] A three-dimensional structure configured to promote adsorption of proteins and cells can be formed by the porous structure. More specifically, the three-dimensional structure may include a plurality of openings (or pores) and a plurality of webs (or struts) that allow proteins and cells to be formed in the radially inward direction. The openings and webs can be formed of the openings and threads of a fabric material or other mesh or net structure. Alternatively, the porous three-dimensional structure can be formed of a foamed or spongy structure, or any other regular or irregular structure having pores that can promote adsorption of proteins and cells. If desired, the porous structure can be formed integrally on the outer surface of the catheter's tubular body, or separately, for example, in the form of the aforementioned sleeve, or can be fabricated directly on the catheter by, for example, electrospinning or spraying.
[0025] The porous three-dimensional structure may comprise one or more single or multiple layers having one or more of the above configurations, such as a fabric sleeve, mesh, foam, or other porous structure. The individual layers may be formed with the same configuration or different configurations. For example, a foamed or spongy structure can be combined with a fabric sleeve surrounding the foam or sponge.
[0026] In one embodiment, the porous structure may form a plurality of first openings and a plurality of second openings, and the first openings and the second openings may have different sizes. In other words, in the case of a fabric material, the mesh size may vary. Thereby, the formation of the above autograft may be improved. In the porous structure having a plurality of layers as described above, the opening sizes may be varied or the same in individual layers so as to allow different cells to adhere to different layers of the three-dimensional porous structure.
[0027] The porous structure, particularly the three-dimensional structure, and more specifically the sleeve, can have a thickness of at least 20 μm, preferably at least 30 μm. The thickness of the porous three-dimensional structure is measured in the radial direction from the outer surface of the tubular body of the catheter to the outer surface of the porous structure. When there is a gap between the porous structure and the outer surface of the catheter body, the thickness of the porous structure can be measured in the radial direction from the inner surface of the porous structure to the outer surface of the porous structure. In other words, in order to improve the function of the sleeve as a support structure for the autograft, the wall thickness of the sleeve should be the minimum dimension. In particular, the minimum radial thickness allows the autograft to grow in the radially inner direction from the outer surface of the porous structure, thereby preventing the overall diameter from substantially increasing after the initial formation of the autograft. It is understood that the total diameter of the catheter can be 12F (4 mm) or less, preferably 9F (3 mm) or less, and in some cases 6F (2 mm) or 4F (1.3 mm) in order to avoid irritation or damage to the blood vessel wall. If the size of the blood vessel is too small for the implanted catheter, mechanical irritation caused can lead to abnormal tissue growth even if there is an autograft present.
[0028] The description of the above solution and the following detailed description of the preferred embodiments will be better understood when read in conjunction with the accompanying drawings. For the purpose of explaining the present disclosure, reference is made to the drawings. However, the scope of the present disclosure is not limited to the specific embodiments disclosed in the drawings.
Brief Description of the Drawings
[0029] [Figure 1a] It is a schematic diagram showing an intravascular blood pump inserted into a patient's heart via different types of access. [Figure 1b] It is a schematic diagram showing an intravascular blood pump inserted into a patient's heart via different types of access. [Figure 2] It is a cross-sectional view showing the catheter of the blood pump of FIG. 1 provided with a sleeve. [Figure 3] It is a diagram showing an embodiment of the braided pattern of the sleeve. [Figure 4] This figure shows another embodiment of the knitted fabric pattern for the sleeve. [Figure 5] This figure shows an alternative embodiment of a porous three-dimensional structure. [Figure 6] This figure shows a further alternative embodiment of a porous three-dimensional structure. [Figure 7] Figure 2 shows a catheter comprising a two-layer porous three-dimensional structure. [Modes for carrying out the invention]
[0030] Figures 1a and 1b show an intravascular blood pump P inserted into a patient's heart H. More specifically, the blood pump P comprises a pump device 1 attached to a catheter 5. The pump device 1 is inserted into the left ventricle LV of the patient's heart H via the catheter 5 and pumps blood from the left ventricle LV into the aorta AO. The illustrated applications are merely illustrative, and the blood pump P of the present invention is not limited to these applications. For example, the reverse application in the right ventricle RV can be envisioned. The blood pump P may be inserted percutaneously, for example, via an access from the thigh, and enter the heart H through the aorta AO (see Figure 1a). Alternatively, the blood pump P may be inserted percutaneously via an access from the axilla, and enter the heart H through the aorta AO via the subclavian artery SA (see Figure 1b). The blood pump P is positioned such that the blood flow outlet 2 is located in the aorta AO outside the patient's heart H, and the blood flow inlet 3, which communicates with the flow cannula 4, is located inside the left ventricle LV. An impeller (not shown) is provided in the pump device 1 to generate blood flow from the blood inlet 3 to the blood outlet 2. The rotation of the impeller is brought about by an electric motor (not shown) installed inside the pump device 1.
[0031] The intravascular blood pump P is advanced into the patient's heart by catheter 5. Here, the pump device 1 is attached to the distal end 15 of catheter 5, which is located opposite the proximal end 16 of catheter 5. As schematically shown in Figure 1, catheter 5 may come into contact with the inner wall of the aorta AO during insertion, operation, or possibly both. This can cause irritation or damage to the vascular wall (induced by surface topology and foreign matter) and promote occlusion of catheter 5 by abnormal proliferation of body tissue. Proteins and other cells contained in the blood adhere to the outer surface of catheter 5. In particular, proteins and cells adhere to the outer surface of catheter 5 first. Thus, known catheters tend to invaginate into vascular tissue, thereby making it difficult to remove the blood pump P from the patient's body. This occurs especially in long-term use, when blood pump P is operated for weeks or months. Removal of an invaginated catheter can cause damage to the blood vessel.
[0032] To reduce or avoid internal tissue growth or abnormal proliferation, a porous three-dimensional structure in the form of a fabric sleeve 6 is provided along at least a portion of the catheter 5, particularly the portion that tends to come into contact with the inner wall of the blood vessel. The sleeve 6 was thought to induce fibrinogen adhesion and promote internal tissue growth, but in reality, the opposite was found to occur, as autografts 7 (see Figure 2) that slide along the inner wall of the blood vessel form on the sleeve 6, as will be explained in more detail below.
[0033] Figure 2 schematically shows a cross-section of a catheter 5 with a sleeve 6 attached. The catheter 5 comprises a tubular body 10 having an outer surface 8 and a lumen 9. The sleeve 6 comprises a tubular body 17 having a distal end 11 and a proximal end 12, and is attached to the body 10 of the catheter 5 by appropriate attachment techniques (in particular, solvent bonding that does not require the use of additional adhesives). As indicated by reference numerals 13 and 14 in Figure 2, the sleeve 6 is attached to the catheter body 10 only at the distal end 11 and the proximal end 12. Thus, since the majority of the sleeve 6 between the ends 11 and 12 is not attached to the outer surface 8 of the catheter body 10, the mechanical properties of the catheter 5 are not substantially affected by the sleeve 6. Furthermore, although the sleeve 6 is shown as being formed as a single layer, it is understood that the sleeve 6 may be composed of multiple layers. These layers may be identical or different from each other, for example, with respect to the size of the opening formed by the knitted fabric, and / or with respect to the layer material.
[0034] The fabric sleeve 6 may be constructed from a warp-knitted fabric. Warp-knitted fabrics have good flexibility properties and provide a support structure with openings to facilitate the adsorption of autografts 7. Other fabric materials, such as knotted fabrics, woven fabrics, nonwoven materials, or combinations thereof, can be used if they are suitable for inducing the formation of autografts and supporting them. Examples of known warp-knitted fabrics found to be particularly suitable for sleeve 6 are schematically shown in Figures 3 and 4. Figure 3 shows a knitted fabric 20 as a 1x1 knit (also known as tricot). Figure 4 shows a knitted fabric 30 as a 2x1 knit. To visualize the knitting pattern, individual yarns 21 from the yarn group 22 are highlighted in Figure 3. Openings 23, 24 of different sizes are formed between the yarns 21, 22 to facilitate the adsorption of fibrinogen and further adhesion of blood cells to form autografts 7. The same applies to the yarns 31, 32 and openings 33, 34 of the knitted fabric 30 shown in Figure 4. The yarns 21, 22, 31, and 32 are preferably formed from multifilaments to reinforce the three-dimensional structure of the sleeve 6.
[0035] The autograft 7 grows inside the three-dimensional structure provided by the sleeve 6 (particularly the warp-knitted fabric 20, 30 consisting of multifilaments as described above). Since the autograft 7 is stably supported by the sleeve 6, it does not collapse or loosen and provides a slippery self-coating that prevents the catheter 5 from adhering to the inner wall of the blood vessel. Because the autograft 7 grows inside the sleeve 6, the overall diameter of the catheter 5 does not substantially expand after the initial formation of the autograft 7. The autograft 7 covers the sleeve 6, thereby preventing the catheter 5 from being encapsulated as a foreign body in the area of the sleeve 6 and allowing it to be easily removed without causing trauma to the blood vessel. Furthermore, even if trauma occurs when the blood pump P is first inserted into the patient, healing may begin even while the blood pump P is operating with the catheter 5 positioned in the blood vessel.
[0036] Thus, intentionally and willingly adsorbing proteins and other cells onto the sleeve 6 has an unexpected effect: instead of causing the catheter 5 to invaginate into the blood vessel wall, it creates a self-coating that allows the catheter to slide freely within the blood vessel and prevents invagination. This unexpected effect can be explained by differences in the transition processes. That is, autograft formation begins as soon as the porous structure is immersed in blood, but the coating of the catheter by abnormal proliferation takes several weeks. Therefore, as soon as the autograft is present (usually within a few days), the stimulus that induces abnormal proliferation from the blood vessel wall to the adjacent catheter ceases, and abnormal proliferation does not occur.
[0037] Figures 5 and 6 schematically illustrate further alternative embodiments of a porous three-dimensional structure that may be applied to a catheter instead of, or possibly in addition to, the sleeve 6 described above. The formation of the autograft occurs in the same manner as described above for the sleeve 6. Referring to Figure 5, the porous three-dimensional structure 40 may be formed by electrospinning in one or more layers and may consist of a plurality of filaments 41 to form openings 42 to allow for the formation of autografts 7 as described above. The filaments 41 and thus the openings 42 can be arranged irregularly to desired dimensions. Electrospinning allows the porous structure 40 to be fabricated directly on the catheter 5. Similarly, a foamed or spongy structure 50 having openings 51 as shown in Figure 6 may be formed directly on the catheter 5.
[0038] Figure 7 shows the catheter 5 of Figure 2, which has a multilayered three-dimensional structure on its outer surface 8. In this embodiment, the multilayered structure has two porous layers 6a and 6b. The two layers 6a and 6b may differ. For example, the inner layer 6a may be formed directly on the outer surface 8 as a foam or by electrospinning a filament, and the outer layer 6b may be formed as a fabric sleeve.
Claims
1. A method for manufacturing a catheter (5) for an intravascular blood pump (P) to be inserted percutaneously into a patient's blood vessel, wherein the catheter (5) comprises an elongated tubular body (10) extending between a proximal end (16) and a distal end (15) and having an outer surface (8), and the catheter (5) includes a porous three-dimensional structure (6) in at least a portion of the outer surface (8) that is configured to be positioned within the patient's blood vessel during the operation of the blood pump (P), The aforementioned manufacturing method is The process includes directly fabricating the porous three-dimensional structure (6) on the tubular body (10) of the catheter (5), A manufacturing method wherein the porous three-dimensional structure (6) is directly fabricated on the tubular body (10) of the catheter (5) by electrospinning or spraying.
2. A manufacturing method according to claim 1, wherein the porous three-dimensional structure (6) comprises melt-spun filaments.
3. A manufacturing method according to claim 1 or 2, wherein the porous three-dimensional structure (6) consists of a single layer (6) or a plurality of layers (6a, 6b).
4. A manufacturing method according to claim 3, wherein the porous three-dimensional structure (6) comprises a first layer (6a) having a foamed or sponge-like structure and a second layer (6b) in the form of a fabric sleeve.
5. A manufacturing method according to any one of claims 1 to 4, wherein the porous three-dimensional structure (6) has a plurality of first openings and a plurality of second openings formed thereon, and the first and second openings are of different sizes.
6. A manufacturing method according to any one of claims 1 to 5, wherein the porous three-dimensional structure (6) comprises a non-absorbent material.
7. A manufacturing method according to any one of claims 1 to 6, wherein the porous three-dimensional structure (6) comprises a radiopaque material.
8. A method for manufacturing according to any one of claims 1 to 7, wherein the porous three-dimensional structure (6) comprises at least one of polyethylene, polypropylene, polyamide, polyethersulfone, polyethylene terephthalate, polyurethane, and natural protein fibers.
9. A manufacturing method according to any one of claims 1 to 8, wherein the porous three-dimensional structure (6) is configured to promote the adsorption of fibrinogen.
10. A manufacturing method according to any one of claims 1 to 9, wherein the porous three-dimensional structure (6) has a thickness of at least 20 μm.
11. A manufacturing method according to any one of claims 1 to 10, wherein at least a portion of the outer surface (8) is configured to promote protein adsorption.
12. A manufacturing method according to claim 2, wherein the melt-spun filament has a diameter in the range of 1 μm to 100 μm.
13. A manufacturing method according to claim 12, wherein the melt-spun filament has a diameter in the range of 2 μm to 30 μm.
14. A manufacturing method according to claim 13, wherein the melt-spun filament has a diameter in the range of 10 μm to 20 μm.
15. A manufacturing method according to claim 3, wherein the plurality of layers (6a, 6b) have different compositions.
16. A manufacturing method according to claim 4, wherein the second layer (6b) surrounds the first layer (6a).
17. A method for manufacturing according to claim 8, wherein the natural protein fiber is a silk fiber.
18. A manufacturing method according to claim 9, wherein the three-dimensional structure (6) comprises a plurality of openings (23, 24; 33, 34) and a plurality of threads (21, 22; 31, 32) that allow the adsorption of fibrinogen in the radially inward direction.
19. A manufacturing method according to claim 10, wherein the porous three-dimensional structure (6) has a thickness of at least 30 μm.
20. A method for manufacturing according to claim 11, wherein the protein is a blood protein.
21. A method for manufacturing according to claim 20, wherein the blood protein is fibrinogen.
22. A manufacturing method according to claim 15, wherein one of the plurality of layers (6b) surrounds another of the plurality of layers (6a).