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EP-2799035-B2 - Implant for influencing blood flow

EP2799035B2EP 2799035 B2EP2799035 B2EP 2799035B2EP-2799035-B2

Inventors

  • HANNES, RALF
  • MONSTADT, HERMANN
  • SCHNEIDER, MANUEL

Dates

Publication Date
20260513
Application Date
20080305

Claims (11)

  1. Combination of an implant (1) for blood vessels for influencing the blood flow in the region of aneurysms (A) and a guide wire (10), the implant (1) having a wall made of individual filaments (2, 2') which are combined to form a round braid, the round braid being a continuous braid cut to length, assuming an elongated shape having a reduced diameter in an introduction catheter (11) and expanding at the implantation site with adaptation to the vessel diameter and an increase in surface coverage, the filaments (2, 2') of the round braid having shape-memory properties, characterised in that the round braid is set in such a way that, upon cessation of the stretching forces that bring the round braid into the elongated shape, it expands so strongly that, in the region of an aneurysm neck, at which the vessel has a greater vessel diameter in comparison with the adjoining healthy vessel section, it assumes a higher surface coverage in comparison with the adjoining healthy vessel section, and wherein the implant (1) is coupled to the guide wire (10) via a retaining element (12), wherein, at the proximal end of the round braid, filament ends are brought together at least in pairs and are permanently interconnected, wherein the interconnected filament ends are atraumatically reshaped and designed as connecting elements (6) for the retaining element (12), and the retaining element (12) has peripheral recesses (13) into which the connecting elements (6) are fitted.
  2. Combination according to claim 1, characterised in that the filaments (2, 2') consist at least partially of nitinol.
  3. Combination according to claim 1 or 2, characterised in that the connecting elements (6) are spherical end pieces arranged on the filament ends and having a defined diameter.
  4. Combination according to one of the preceding claims, characterised in that the filament ends are welded to one another.
  5. Combination according to one of the preceding claims, characterised in that the filament ends are brought together and interconnected in the axial direction.
  6. Combination according to one of the preceding claims, characterised in that the braid structure has a surface coverage by the filaments (2, 2') in the range of 30 to 80%.
  7. Combination according to claim 6, characterised in that the surface coverage is 40 to 70%.
  8. Combination according to one of the preceding claims, characterised in that the filaments (2, 2') of the round braid are sheathed with plastics material.
  9. Combination according to one of the preceding claims, characterised in that the round braid is sheathed with a film or has meshes completely or partially filled with plastics material.
  10. Combination according to one of the preceding claims, characterised in that the implant contains marker elements.
  11. Combination according to claim 10, characterised in that the marker elements are filaments of platinum or platinum alloys which are woven into the round braid or helically surround filaments (2, 2') of the round braid.

Description

The invention relates to a combination of a blood vessel implant and a guide wire, wherein the implant has a wall made of individual filaments that are combined to form a circular mesh. The implant is particularly intended to influence blood flow in the area of arteriovenous malformations, such as fistulas and aneurysms. It can also be used to treat ischemic stroke, for example, to restore, increase, or maintain blood flow. The implant can be designed to be retractable. Arteriovenous malformations can lead to significant impairments and risks, even death, in a patient. This is especially true for arteriovenous fistulas and aneurysms, particularly when they occur in the cerebral region. Typically, such malformations are closed using implants. These implants are usually placed endovascularly using catheters. The implantation of platinum coils has proven particularly effective in treating aneurysms. These coils fill the aneurysm more or less completely, largely blocking blood flow and leading to the formation of a local thrombus that fills and ultimately closes the aneurysm. However, this treatment method is only suitable for aneurysms with a relatively narrow access point to the vascular system, so-called berry aneurysms. In aneurysms with a wide access point to the vessel, the implanted coils are at risk of re-emergence. to be flushed out and cause damage in other areas of the vascular system. In such cases, it has been suggested that a type of stent be inserted to "mesh" the opening of the aneurysm, thereby preventing the occlusive coils from being washed out. However, such stents, which have a relatively wide-mesh wall, have a number of disadvantages. Firstly, the stent's open-mesh structure allows unimpeded blood flow into the aneurysm. However, if the aneurysm is not sufficiently filled with the occlusive agent, the pressure on the vessel wall remains unchanged. Under these circumstances, further treatment is difficult because the stent obstructs access to the aneurysm and hinders the introduction of additional occlusive agents. Another disadvantage is the stent's lack of adaptability to its insertion site. For optimal function, the stent should fit snugly against the vessel wall without exerting excessive pressure on it. Unlike stents designed to widen the vessel in cases of stenosis, these stents are more like a cuff, intended to have minimal impact on the vessel lumen and the endothelial wall. Consequently, even when specifically selected for a particular application, these stents offer only limited adaptability to the requirements. Wire mesh stents have long been known for use in the coronary arteries. These stents are generally manufactured as circular meshes, with the individual wire filaments forming the stent wall in opposing spiral or helical layers. This creates a mesh structure that provides radial support while remaining permeable to blood. One problem with these stents designed as a circular mesh is the loose ends at the free ends, which, due to their small diameter, can be traumatic. According to US-A-4 655 771 (Wallsten In this type of stent, which is designed as a circular mesh, U-shaped connecting elements between the loose ends create an atraumatic effect at its ends. However, these U-shaped connecting elements cause stresses that can lead to stent deformation. According to US-A-5 061 275 (Wallsten et al. The loose ends of such wire stents are melted by laser treatment to prevent trauma. The stent described there also consists of a circular mesh in which the individual wires have indentations in the area of the nodes to allow for tension-free fixation within the wall. US 2002/165601 shows a self-expanding, braided stent. Stents of this type, consisting of a circular mesh of filaments, are hydraulically expanded at the insertion site using a balloon and fixed to the vessel wall when used to treat stenoses. During insertion, the balloon, attached to a guide wire, serves as a delivery vehicle onto which the stent is crimped. However, such a delivery vehicle should not be used for implants intended to influence or channel blood flow in the cerebral region; rather, an implant that automatically adapts to the vessel diameter and adheres to the vessel wall would be advantageous in this case. Another problem with wire mesh stents or implants is their manufacturing. One advantage is manufacturing them as a braided, continuous tube that is cut to the desired length. However, this process creates loose wire ends at both ends of the cut tube, which require complex finishing, for example, using the connecting elements mentioned above. Accordingly, the invention is based on the objective of providing a combination of an implant that can influence blood flow in a vessel in such a way that aneurysms can be isolated from the blood flow as far as possible, and a guide wire. The implant is intended to With optimal selection of implant diameter to vessel diameter, it should be able to adapt to the respec