Vaso-occlusive devices comprising complex-shape proximal portion and smaller diameter distal portion

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DESCRIPTION

Vaso-occlusive devices comprising a complex shaped proximal part and a smaller diameter distal part

FIELD OF THE INVENTION

Compositions and methods for treating aneurysms are described in the present invention. In particular, vasoocclusive devices are disclosed, as well as methods for the manufacture and use of these devices.

BACKGROUND

An aneurysm is a dilation of a blood vessel that poses a health risk caused by possible rupture, clotting, or dissection. A ruptured aneurysm in the brain causes a stroke, and a ruptured aneurysm in the abdomen causes shock. Brain aneurysms are usually detected in patients after an attack or hemorrhage and can lead to considerable morbidity or mortality.

There are a wide variety of materials and devices that have been used to treat aneurysms, including platinum and stainless steel microcoils, polyvinyl alcohol (Ivalone) sponges, and other mechanical devices. Vaso-occlusion devices are surgical tools or implants that are placed within the vascular system of the human body, usually through a catheter, to block the blood flow that circulates through a vessel that constitutes that part of the vascular system, by forming of a plunger, or to form said plunger inside an aneurysm located in the vessel. A widely used vaso-occlusive device consists of a helical coil of wire, the coils of which may be sized to fit the walls of the vessels. Other less rigid helical devices have been described, as well as those that include woven braids. For example, vaso-occlusion devices are surgical tools or implants that are placed within the vascular system of the human body, usually through a catheter, to block the blood flow that circulates through a vessel that constitutes said part of the vascular system. by forming a plunger or to form said plunger within an aneurysm formed in the vessel.

For example, in US Patent No. 4,994,069 to Ritchart et al., A vasoocclusive coil is described that assumes a linear helical configuration when stretched and a folded and twisted configuration when relaxed. The stretched state is used to place the coil in the chosen location (by passing it through the catheter) and the coil assumes a relaxed configuration, which is more suitable for occlusion of the vessel, once the device has been positioned in this way . Ritchart et al. describe various "complex" three-dimensional shapes. The secondary shapes of the spirals described include "flower" shapes and double vortices. A random shape is also described. Other less rigid helical devices have been described, as well as those that include woven braids. See, for example, US Patent No. 6,299,627.

Other three-dimensional vaso-occlusive devices have been described. A filled three-dimensional vaso-occlusive coil is disclosed in US Patent No. 5,624,461 to Mariant. Embolization coils having coiled helical shapes are described in US Patent No. 5,639,277 to Mariant and in US Patent No. 5,649,949 to Wallace. et al., variable section conical vaso-occlusive coils are described.

In US Patent No. 5,334,210, in the name of Gianturco, a vascular occlusion mechanism is described comprising an occlusion bag of a collapsible material and a filled element, for example, a helical coil with a J-shaped hook at the proximal end. The bag expands to form a diamond-shaped structure and the filling element is forced into a twisted configuration as it is inserted into the pocket of the collapsible bag.

Implantable devices using coils of certain shapes are shown in US Patent No. 5,537,338 to Purdy. Purdy described a multi-element intravascular occlusion device in which coils of a particular shape can be used. In US Patent No. 5,536,274, in the name of Neuss, a spiral implant is shown that can take various secondary forms. Some complex shapes can be formed by interconnecting two or more spiral-shaped implants.

Vaso-occlusive coils have also been described that have few or no inherent secondary forms. For example, co-owned US Patent Nos. 5,690,666 and 5,826,587 to Berenstein et al. Describe coils that have little or no shape upon introduction into the vascular space.

Various mechanically removable devices are also known. For example, in US Patent No.

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5,234,437, in the name of Sepetka, shows a procedure for unscrewing a helically wound coil from a pusher provided with mating surfaces. An embolization coil mechanism is shown in US Patent No. 5,250,071, in the name of Palermo, which uses attachable hooks mounted on both the pusher and the embolization coil. In US Pat. No. 5,261,916, in the name of Engelson, shows a removable vaso-occlusive pusher-coil mechanism provided with a keyway type coupling with an engaging ball. In the US patent No. 5,304,195, in the name of Twyford et al., a vaso-occlusive pusher-coil mechanism is shown with a fixed wire, extending proximally and having a ball at its proximal end and a pusher with a similar end. The two ends are engaged and disengaged when ejected from the distal tip of the catheter. US Patent No. 5,312,415, in the name of Palermo, also shows a method of using a guidewire having a section capable of interconnecting with the inside of the helically wound coil. US Patent No. 5,350,397, in the name of Palermo, shows a pusher having a groove at its distal end and a pusher through its shaft. The pusher sheath will remain attached to the end of an embolization coil and will be released by pushing the axially positioned pusher wire against the member at the proximal end of the vaso-occlusive coil.

The U.S. patent application 2002/0019647 A1 discloses an implantable vaso-occlusive device provided with a complex three-dimensional structure in a relaxed configuration that can be used in the approximate shape of an anatomical socket.

US patent application 2002/0107534 A1 discloses a microcoil having a second configuration comprising a plurality of tangentially interconnected, substantially circular loops whose diameter gradually decreases.

However, none of the above documents shows a device as described herein.

SUMMARY OF THE INVENTION

Any of the devices described herein may also comprise a detachable fitting which can be detachably connected to a positioning device (eg, a pusher element). The release splice can be placed anywhere on the device, for example at one or both ends of the device. In certain embodiments, the separable joint or joints consist of an electrolytically removable mechanism [The present invention is defined by the scope of appended claim 1] and adapted to be removed by the application of a current; a mechanically detachable mechanism adapted to detach by movement or pressure; a thermally removable mechanism adapted to be removed by localized application of heat to the joint; a radiation removable mechanism adapted to be removed by applying electromagnetic radiation to the splice, or combinations thereof.

Those skilled in the art will readily conceive of these and other embodiments of the invention upon reading the present disclosure.

BRIEF DESCRIPTION OF THE FIGURES

Fig. 1 is an overview illustrating an exemplary device as described herein. The proximal part (10) has an overall diameter ("A") that is substantially greater than the diameter ("D") of the distal part (20).

It should be understood that the drawing illustrates an exemplary embodiment and is not to be construed as a limitation on the scope.

DESCRIPTION OF THE INVENTION

Occlusive (embolizing) compositions are described. The compositions described herein are used in vascular and neurovascular applications and are particularly useful in the treatment of aneurysms, for example small diameter, curved or difficult to access vasculatures, for example aneurysms such as brain aneurysms. Also constituting aspects of the present description are procedures for the manufacture and use of these vasoocclusive elements.

It should be noted that, as used in the present specification and in the appended claims, the singular forms "a", "an", "the" and "the" include plural referents, unless the content clearly indicates otherwise. contrary. Thus, for example, reference to a device comprising "one loop" includes devices comprising two or more loops.

The self-forming coil designs of the present invention are particularly useful in the treatment of aneurysms. The designs described herein provide an improvement over the

ES 2 440 194 T3 known devices, for example, with regard to ease of placement. The inclusion of a distal portion with a diameter smaller than the diameter of the main proximal portion of the device allows the devices to be placed more easily in the chosen vessel. In particular, embolization coils have a tendency for the initial (distal) loop that is introduced into an aneurysm to protrude into the mother vessel as the first (distal) loop is inserted. The designs described herein increase the ease with which a coil with a complex shape is inserted into an aneurysm or other injury by making the distal loop substantially smaller than the more proximal loops and therefore smaller than the dimensions of the aneurysm, so that it will sit in the aneurysm space without sliding out before placing the rest of the ties.

Thus, the devices described herein comprise a proximal part with a three-dimensional shape defining a first diameter and a second distal part with a two-dimensional shape defining a second diameter, wherein the second diameter is substantially smaller than the first diameter.

The term "complex" (claim 1) refers to any three-dimensional shape that defines multiple planes. Non-limiting examples of complex three-dimensional shapes include non-overlapping loop structures with spherical, elliptical, cubic, random, flower, vortex, conical, spherical, etc. shape. See, for example, US Patent Numbers: 4,994,069, 5,624,461, 5,649,949, 5,522,822, 5,935,145, 5,690,666, 5,826,587, and 6,635,069. Also, the distal portion may adopt any of these various configurations.

The proximal part has a three-dimensional shape while the distal part has a two-dimensional shape (such as a loop or "J" shape). The expression "two-dimensional shape" refers to any shape in which the configuration of that part of the devices defines a plane. It will be apparent that, to obtain a diameter (for example, a diameter that is smaller than the total diameter of the proximal part), a two-dimensional distal part must include some kind of circular shape, for example a loop, 'J' shape », An ellipse, and so on. In a preferred embodiment, the distal portion has a single loop configuration.

Fig. 1 shows an exemplary device comprising a complex embolization coil with any complex non-helical shape (10), with the most distal loop or loops (20) drawn in a darker gray. The most distal component (20) has a diameter ("D") substantially smaller than the total diameter ("A") of the loops in the complex shaped part (10) of the device. In fig. 1 the delivery catheter (35) is also shown.

In a preferred embodiment, the diameter of the distal portion (20) is approximately 75% of the total diameter (eg, the diameter of one or more of the loops) in the complex portion. However, it will be clear that the diameter of the distal part (for example, the loop) ("D") can be greater or less than 75% of the diameter of the complex proximal part ("A"), provided that the diameter of the the distal part is smaller than the diameter of the proximal part.

As shown in fig. 1, the two parts are preferably made of the same materials and also preferably form an integral unit. However, it is also contemplated that the two parts may be made of different materials and / or may be produced separately and joined together after manufacture.

The material (s) used in the construction of the vasoocclusive devices described herein can be any of a wide range of materials; preferably, the material is a radiopaque material such as a metal or a polymer. Suitable metals and alloys include platinum group metals, especially platinum, rhodium, palladium, rhenium; as well as tungsten, gold, silver, tantalum, and alloys of these metals. These metals have considerable radiopacity and can be tailored in their alloys to achieve an appropriate mix of flexibility and stiffness. They are also, to a large extent, biologically inert. A platinum / tungsten alloy is especially preferred.

The device can also be made of any one of a wide variety of stainless steels if it is allowed to sacrifice some of the radiopacity. Materials that maintain their shape despite high stress are highly desirable construction materials from a mechanical point of view. Certain "superelastic alloys" include nickel / titanium alloys (atomic percentage 48 to 58% nickel and optionally small amounts of iron); copper / zinc alloys (atomic percentage 38-42% zinc); copper / zinc alloys containing 1 to 10% by weight of beryllium, silicon, tin, aluminum or gallium; or nickel / aluminum alloys (atomic percentage 36 to 38% aluminum). Particularly preferred are the alloys described in US Patent Nos. 3,174,851, 3,351,463, and 3,753,700. The titanium / nickel alloy known as "nitinol" is especially preferred. These are very strong alloys that tolerate considerable bending without deformation, even when used in the form of very small diameter wire. If an alloy such as nitinol is used in the device, the diameter of the coiled wire can be considerably smaller than that used when using platinum or a relatively more ductile platinum / tungsten alloy as the material of construction.

The devices can also comprise a wide variety of synthetic and natural polymers, such as

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Dacron (polyester), polyglycolic acid, polylactic acid, fluoropolymers (polytetrafluoroethylene), nylon (polyamide) or even silk. Other exemplary polymers that may be used include, but are not limited to: polyurethanes (including copolymers with soft segments containing esters, ethers, and carbonates), ethers, acrylates (including cyanoacrylates), olefins (including polymers and copolymers of ethylene, propylene, butenes, butadiene, styrene, and thermoplastic olefinic elastomers), polymers based on polydimethylsiloxane, polyethylene terephthalate, cross-linked polymers, non-cross-linked polymers, rayon, cellulose, cellulose derivatives such as nitrocellulose, natural rubbers, polyesters such as lactides, glycolides, caprolactones and their copolymeric and acid derivatives, hydroxybutyrate and polyhydroxyvalerate and their copolymers, polyether esters such as polydioxynone, anhydrides such as polymers and copolymers of sebacic acid, hexadecanedioic acid, and other di-ortho esters. If a polymer is used as the main component of the vasoocclusive element, it is ideally filled with a certain amount of a known radiopaque material, such as powdered tantalum, powdered tungsten, bismuth oxide, barium sulfate and the like.

The overall diameter of the deployed device is generally between 2 and 30 millimeters (or any diameter in between), for example: 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm or 30mm. Most aneurysms located in the cranial vascular system can be treated by one or more devices with such diameters. Of course, such diameters are not a critical aspect of the invention.

Attachment of various fibrous materials to the coil of the invention in order to add thrombogenicity to the resulting mechanism is also contemplated in the present invention. Fibrous materials can be fixed in various ways. Fibers can be looped through the coil or tied to the coil and continued axially down the coil. Another variant is to tie the strand to the spiral. The strands can be tied in various places through the spiral to provide a large area of ​​embolus formation points. The main spiral can be covered by a fibrous braid. The process for producing such a variant is described in US Patent Nos. 5,226,911 and 5,304,194, in the name of Chee. The process for producing the fibrous braid is described in US Patent No. 5,382,259, issued January 17, 1995 to Phelps and Van.

The coils described herein may also include other additives, for example, any material that exhibits biological activity in vivo, such as cosolvents, plasticizers, coalescing solvents, bioactive agents, antimicrobial agents, antithrombogenic agents (eg, heparin), antibiotics. , pigments, radiopaquents and / or ionic conductors which can be coated using any suitable method or can be incorporated into the element or elements during production. Thus, bioactive materials can be used to coat the device (eg, heparin) and / or can be placed in the vessel before, after, or at the same time as the placement of one or more devices such as described herein. document.

One or more of the elements can also be fixed to each other at one or more points. For example, to the extent that various elements are thermoplastic, they can be fused or fused with other elements of the devices. Another possibility is to adhere or fix them in another way. Furthermore, the various elements can be fixed to each other at one or more points.

USE PROCEDURES

The devices described herein are frequently inserted at a selected point, using the procedure briefly explained below. This procedure can be used in the treatment of various conditions. For example, in treating an aneurysm, the aneurysm itself will be filled (partially or totally) with the compositions described herein.

To access this site with a catheter, conventional catheter insertion and navigation techniques using floating guides or devices can be used. The mechanism will allow it to be advanced fully through the catheter to place the vasoocclusive device at the chosen point, but with enough of the distal end of the delivery mechanism protruding from the distal end of the catheter to allow it to be detached from the implantable vasoocclusive device. For use in peripheral or neuronal surgery, the delivery mechanism will typically have a length of about 100 to 200 cm, more typically 130 to 180 cm in length. The diameter of the delivery mechanism is typically in the range of 0.25 to about 0.90 mm. In sum, the occlusive devices (and / or additional components) described herein are typically loaded into a vehicle for introduction into the delivery catheter and inserted at the chosen site using the procedure briefly described below. This procedure can be used in the treatment of various conditions. For example, in the treatment of an aneurysm, the aneurysm itself can be filled with embolizing materials (for example, vaso-occlusive elements and / or bioactive materials and liquid embolizers), which cause the formation of an embolus and are later replaced at least partially by neovascularized collagenous material formed around implantable vaso-occlusive devices.

To reach the selected point through the vascular system, a collection of catheters and / or wires is used.

ES 2 440 194 T3 guides chosen for this purpose. Obviously, if the point were to be found in a remote location, for example in the brain, the procedures to reach this point would have certain limitations. A widely accepted procedure appears in US Patent No. 4,994,069 to Ritchart et al. It employs a fine endovascular catheter such as that shown in US Patent No. 4,739,768 to Engelson. First, a large catheter is inserted through an entry point into the vasculature. Normally, it would be done through a femoral artery in the groin area. Sometimes other entry points located on the neck are chosen, which are generally well known to physicians working in this field of medicine. Then, once the introducer is in place, a guide catheter is used to provide safe passage from the entry point to an area close to the site to be treated. For example, when treating a point in the human brain, a guide catheter would be chosen that extends from the point of entry into the femoral artery, ascending through the large arteries that extend to the heart, surrounding the heart. through the aortic arch, and traveling downstream through one of the arteries that extend from the superior side of the aorta. A guidewire and neurovascular catheter such as that described in the Engelson patent are then placed through the guide catheter. Once the distal end of the catheter is in position at the target site, often by positioning its distal end through the use of a radiopaque marker material and fluoroscopy, the catheter is cleared. For example, if a guidewire has been used to position the catheter, it will be removed from the catheter and then the mechanism will be advanced, including, for example, the vasoocclusive device at the distal end.

Once the treatment point has been reached, the vaso-occlusive device is extruded, for example by loading it onto a pusher wire through a mechanically or electrolytically separable joint (e.g., a GDC joint which can be separated by application heat, electrolysis, electrodynamic activation, coherent laser light or other means). In addition, the vasoocclusive device supports a design that includes multiple detachment points, as described in co-owned US Patent Nos. 6,623,493 and 6,533,801 and International Patent Publication WO 02 / 45596. They are held in place by gravity, shape, size, volume, a magnetic field, or combinations of these factors.

Modifications to the procedure and vasoocclusive devices described above and the procedures for using them in accordance with the present specification will be apparent to those skilled in this mechanical and surgical technique.