Abstract: A stent graft extends in a flow lumen to span a defective portion of the flow lumen and seal the defective portion from further blood contact. The stent graft includes a pair of apertures, from which extensions project into the renal arteries to seal the passage of blood into the renal arteries from the abnormality. The apertures are larger than the opening of the renal arteries, such that the apertures need not be centered with the renal arteries to enable placement of the extensions. The aperture opening and side branch extensions contain hook and loop structures to provide a variably positionable seal of the aperture opening.

Abstract: A medical implant (20) includes first and second ring members (22, 24), each including a resilient framework (26) having a generally cylindrical form. A tubular sleeve (28) is fixed to the first and second ring members so as to hold the ring members in mutual longitudinal alignment, thereby defining a lumen (32) passing through the ring members. A constricting element (30) is fit around the sleeve at a location intermediate the first and second ring members so as to reduce a diameter of the lumen at the location.

Abstract: A medical flow restrictor that may be used to exclude a saccular aneurysm from the circulatory system. The device, a thin walled, foil-like shell, is compacted for delivery. The invention includes the device, electroforming fabrication methods, delivery assemblies, and methods of placing, and using, the device. A device with an aneurysm lobe and an artery lobe self-aligns its waist at the neck of an aneurysm as the device shell is pressure expanded. Negative pressure is used to collapse both the aneurysm lobe and the artery lobe, captivating the neck of the aneurysm and securing the device. The device works for aneurysms at bifurcations and aneurysms near side-branch arteries. The device, unlike endovascular coiling, excludes the weak neck of the aneurysm from circulation, while leaving the aneurysm relatively empty. Unlike stent-based exclusion, the device does not block perforator arteries. This exclusion device can also limit flow through body lumens or orificers.

Abstract: Methods for using a reusable quick release fastener system include engaging and disengaging fastening devices composed of elastomers or shape memory polymers and their composites wherein the fastening devices may be of any number of geometrical shapes such that the mating geometries of each device are compatible with one another. The fastening devices provide an easy and near silent closure mechanism for a container, for example. Thus, the methods for using reusable quick release fastener systems including the fastening devices made of elastomers or shape memory polymers can be used to attach one part to another or to quietly close a pocket, box, or other container, for example.

Abstract: The present invention is directed to a novel device and method for providing a disposable endotracheal intubation device for use with an auxiliary passageway serving as a guide for the placement of an orogastric or other enterally directed device in a patient. The present invention pertains to a medical catheter device, removably attachable to an endotracheal tube, for guiding the path of an enteral tube into the esophagus of a patient. The catheter device preferably employs an adjustable clamp to fix the position of the catheter relative to the endotracheal tube. The present invention also pertains to a combination medical intubation device comprising an endotracheal tube and a catheter proximate the endotracheal tube to guide the path of an enteral tube. The present invention also pertains to a method of intubating a patient using this combination medical intubation device.

Abstract: The minimally invasive pulmonary artery band includes an elongate tube having a reservoir of inflation fluid attached at one end and a clamp head attached to the other end. The clamp head is a hexagonal clamp frame having a gap to facilitate wrapping the clamp frame around the pulmonary artery. The clamp frame includes at least one balloon element attached thereto. The balloon element is selectively inflatable from the inflation fluid provided by the reservoir. The balloon element is configured for inflation into predefined shapes, and the pulmonary artery band allows for fine adjustments to compression and the shape of compression of the pulmonary artery to gradually reach a predefined state of occlusion.

Abstract: The present invention provides apparatus and methods for a conduit, such as an implantable conduit for a vessel. The conduit may comprise a main member and a side-branch member. The conduit may be implanted with the side-branch member initially disposed within the main member. When positioned, the side-branch member may then be extended from within the main member and into a vessel side-branch. The materials for the conduit may include circumferentially distensible and/or low recoil materials. The materials for the conduit may be constructed by various techniques and may include materials with enhanced flexibility and kink resistance.

Abstract: The present invention relates to a drug eluting stent for delivering therapeutic agents to a body lumen. The stent includes an expandable substrate configured for implantation in a vessel of a human body and a therapeutic agent composition coated over the stent. The balloon catheter shaft has a resilient unit that helps to transmit a force to the distal end, thereby helping to cross lesions.

Abstract: A medical device detachment system receives an elongate delivery member, having a lumen, and an elongate core member. The system includes a housing, a user input mechanism for receiving a user input to effect detachment of a medical device, such as an embolic coil, from a distal end of the delivery member, and a grasping mechanism for grasping and moving a proximal end of the core member relative to a proximal end of the delivery member. The system also includes a first sensor detecting positioning of the proximal end of the core member within the housing, and a second sensor, detecting movement of the grasping mechanism. An indicator is connected to the first and second proximity sensors and provides feedback to a user.

Abstract: An arteriovenous graft system is described. The arteriovenous graft system includes an arteriovenous graft that is well suited for use during hemodialysis. In order to minimize or prevent arterial steal, at least one valve device is positioned at the arterial end of the arteriovenous graft. In one embodiment, for instance, the arteriovenous graft system includes a first valve device positioned at the arterial end and a second valve device positioned at the venous end. In one embodiment, the valve devices may include an inflatable balloon that, when inflated, constricts and closes off the arteriovenous graft. If desired, a single actuator can be used to open and close both valve devices.

Abstract: A delivery system for an occlusion balloon includes a delivery catheter and a balloon releasably detached thereto. The balloon can include a base portion that is threaded onto the end of the delivery catheter. The balloon can include a one-way valve or septum in the base portion, through which a filling needle is inserted into a cavity of the balloon. The balloon can be filled with a fluid to expand the balloon and fix the balloon within the patient's body. The balloon can be filled with a hardening material to assist in fixing the balloon in place and occluding the blood vessel. The balloon can include anchoring structure on its outer surface to assist in the fixing the location of the balloon. The delivery device and needle can be detached and withdrawn from the balloon, allowing the septum to close and seal the balloon, leaving the balloon fixed within the body vessel.

Abstract: Devices, systems and methods useable for dilating the ostia of paranasal sinuses and/or other passageways within the ear, nose or throat. A dilation catheter device and system is constructed in a manner that facilitates ease of use by the operator and, in at least some cases, allows the dilation procedure to be performed by a single operator. Additionally, the dilation catheter device and system may be useable in conjunction with an endoscope and/or a fluoroscope to provide for easy manipulation and positioning of the devices and real time visualization of the entire procedure or selected portions thereof. In some embodiments, an optional handle may be used to facilitate grasping or supporting a device of the present invention as well as another device (e.g., an endoscope) with a single hand.

Abstract: An apparatus for deploying and retrieving a self-expanding intravascular stent includes an intravascular delivery wire and floating marker band movably retained over the intravascular stent delivery wire and releasably mounting the self-expanding intravascular stent. The floating marker band is movably retained to a fixed marker band, and a distance between the fixed marker band and the floating marker band is variable and self-adjusting. One or more struts of the self-expanding intravascular stent are releasably constrained between a catheter wall and one or more sides of the floating marker band.

Abstract: A medical device for reducing the volume of a left atrial appendage (LAA) may include an elongate shaft having a distal portion, and a volume-reducing means expandable from a collapsed to an expanded state, the volume-reducing means being releasably attached to the distal portion. The volume-reducing means may include an actuatable frame and an impermeable covering disposed over the frame. The volume-reducing means may be sized to fit within the LAA in the expanded state while maintaining an open fluid flow path from a distal region through the ostium of the LAA. A medical device may include a second volume-reducing means to be placed within and substantially occlude a distalmost region of the LAA. A method may include inserting a volume-reducing means into the LAA, expanding the volume-reducing means, and positioning the volume-reducing means such that an open fluid flow path is maintained through an entire cycle of the heart.

Abstract: A blood clot filter is collapsible toward a longitudinal axis into a collapsed configuration for insertion into a blood vessel, and is radially expandable outwardly from the longitudinal axis to an expanded configuration for contact with the inner wall of the blood vessel at two longitudinal spaced locations. A first plurality of spaced, elongate arms, in the expanded configuration, curve outwardly away from the longitudinal axis toward the leading end of the filter to form a first filter basket and to center a hub at the trailing end of the filter within the vessel. A second plurality of spaced elongate legs angle outwardly away from the longitudinal axis toward the leading edge of the filter in the expanded configuration to form a second filter basket opening toward the leading end. The ends of these legs include hooks to bend and straighten in response to withdrawal force.

Abstract: What is disclosed is a medical device comprising a compressed, cylindrical or oblong, thin-walled, expandable metal structure (a “blockstent”) and a flexible, elongated device (a “delivery catheter”) to position the compressed blockstent into the lumen of a blood vessel segment to be treated, and methods of use for occlusion of treated blood vessel segments. A blockstent can be made with ductile metals such as gold, platinum, or silver such that the blockstent will conform to the shape of the lumen of the treated blood vessel segment during expansion and allow for the shape of the blockstent to be permanently changed by the application of an external force. The surface of the blockstent can be configured to promote local thrombus on the external surface of the blockstent and to promote the growth of tissue into the wall of the blockstent in order to occlude the treated blood vessel and fix the blockstent in place.

Abstract: A medical device comprising a compressed, inflatable, detachable single-lobed metal balloon attached to a catheter and methods of use for occluding blood vessels or treating vascular aneurysms are disclosed. The balloon can be made with ductile metals such as gold, platinum, or silver so that the balloon will conform to the shape of the void space during inflation and so that the balloon can be subsequently shaped by the application of an external force. The balloon can be configured such that it can be detached from the catheter by physical means or by electrolysis. The surface of the balloon can be configured to promote the growth of tissue into the wall of the balloon and to release drugs or pharmacologically active molecules, so that vessel occlusion or the sealing of an aneurysm will be maintained over time.

Abstract: A catheter for delivering luminal prostheses comprises a catheter body having an expandable member near a distal end. The prosthesis has a side hole, and a guidewire extends beneath a proximal portion of the prosthesis and over the exterior of the expandable member. A distal end of the guidewire is retracted proximally from the closest point on the side opening to reduce possible interference with catheter advancement.

Abstract: An environmentally sensitive hydrogel material swells or collapses in response to a parameter such as pH level associated with consumption of food by a patient. This swelling or collapsing is harnessed to treat morbid obesity or some other condition of the patient. The swelling or collapsing of the hydrogel may be used to tighten a gastric band or gastric valve when the patient starts eating; then loosen the band or valve when the patient is between meals. The swelling or collapsing of the hydrogel may also be used to increase the size of a space occupying device in the patient's stomach when the patient starts eating; then decrease the size of the space occupying device when the patient is between meals. The swelling or collapsing of the hydrogel may also be used to selectively restrict the absorption of nutrients within a patient's gastrointestinal tract, such as in the duodenum.

Abstract: An embolization device for occluding a body cavity includes one or more elongated, expansible, hydrophilic embolizing elements non-releasably carried along the length of an elongated filamentous carrier that is preferably made of a very thin, highly flexible filament or microcoil of nickel/titanium alloy. At least one expansile embolizing element is non-releasably attached to the carrier. A first embodiment includes a plurality of embolizing elements fixed to the carrier at spaced-apart intervals along its length. In second, third and fourth embodiments, an elongate, continuous, coaxial embolizing element is non-releasably fixed to the exterior surface of the carrier, extending along a substantial portion of the length of the carrier proximally from a distal tip, and optionally includes a lumenal reservoir for delivery of therapeutic agents. Exemplary methods for making these devices include skewering and molding the embolizing elements.

Abstract: Treatment of aneurysmal blood vessels with local delivery of therapeutic agents thereby reduces or lessens the severity of an aneurysm, and, where used in conjunction with the placement of an excluding device, provides for more rapid recovery of the blood vessel from any disturbance occurring during placement of the excluding device. Therapeutic agents are placed in the aneurysmal site in a time-release carrier medium, such that the therapeutic agent is released into the aneurysmal site over a period of time without the need to provide systemic introduction of the therapeutic agent. The carrier may be introduced through the patient's dermis, such as with the use of a laparoscope, or intravascularly, through the use of a catheter. The carrier may be in a solid matrix, viscous liquid or liquid form.

Abstract: Methods and devices for maintaining vascular access and/or minimizing bleeding during percutaneous interventions. The method can include advancing an access wire through a previously placed access catheter in a contralateral femoral artery to position an inflatable balloon on the access wire in a vascular access sheath located in an ipsilateral femoral artery, without using any additional guidewires to advance the access wire.

Abstract: A removable blood clot filter includes a number of locator members and anchor members disposed radially and extending angularly downward from a hub. The locator members include a number of linear portions having distinct axes configured to place a tip portion approximately parallel to the walls of a blood vessel when implanted and to apply sufficient force to the vessel walls to position the filter near the vessel centerline. The anchor members each include a hook configured to penetrate the vessel wall to prevent longitudinal movement due to blood flow. The hooks may have a cross section sized to allow for a larger radius of curvature under strain so that the filter can be removed without damaging the vessel wall.

Abstract: A circumferentially connected stent in a non-expanded state with a longitudinal axis, includes a first expansion column strut pair having a first expansion strut, a second expansion strut with a joining strut. The first expansion column strut pair defines a chevron shaped slot, and a plurality of the first expansion strut pair forms a first expansion column. A second expansion column strut pair includes a first expansion strut, a second expansion strut and a joining strut. The second expansion column strut pair defines a chevron shaped slot, and a plurality of the second expansion strut pair forms a second expansion column. A first serial connecting strut column is formed of a plurality of first connecting struts, and the first connecting strut column couples the first expansion column to the second expansion column.

Abstract: A modification to allow delivery of a two port medical flow restrictor over a guidewire, and a means to mechanically collapse the new device. A thin walled, foil-like shell, is compacted for delivery. The invention includes the device, delivery assemblies, and methods of placing, and using, the device. A device with an aneurysm lobe and an artery lobe self-aligns its waist at the neck of an aneurysm as the device shell is pressure expanded. Mechanical force collapses both the aneurysm lobe and the artery lobe, captivating the neck of the aneurysm and securing the device. The device works for aneurysms at bifurcations and aneurysms near side-branch arteries. The device, unlike endovascular coiling, excludes the weak neck of the aneurysm from circulation, while leaving the aneurysm relatively empty. Unlike stent-based exclusion, the device does not block perforator arteries. This exclusion device can also limit flow through body lumens or orifices.

Abstract: A method for closing an opening formed in a wall of a body lumen or body tissue can include positioning a splittable carrier tube adjacent to the opening, the carrier tube having a splittable distal end with an outer surface retaining a closure element in a substantially tubular configuration or having an asymmetrically-elongated tubular shape with a trapezoidal longitudinal cross-sectional profile. The method including splitting a distal end of the carrier tube with a splitter and deploying the closure element from the carrier flaps of the carrier tube and over the splitter to allow the closure element to engage at least a portion of the wall of the body lumen or the body tissue and substantially close the opening.

Abstract: The present invention pertains to a stiffened balloon which can be used in angioplasty, endovascular, and valvuloplasty procedures or as a delivery balloon to deliver a stent or a stent-graft. Longitudinally discontinuous stiffening members connected to the expandable balloon stiffen the balloon but allow it to be navigated through curved passages. Projections on the stiffening members may engage, incise, crush, fracture, or pierce occlusions or retain a stent or stent-graft. Radio-opaque portions may be referenced to determine orientation. Longitudinally continuous stiffening members bearing projections and connected to the balloon perform in a similar manner.

Abstract: A sleeve device, system and method are provided for restricting and/or constricting aneurysms. More particularly, a sleeve and/or a double-walled sleeve is located in or on a vessel in the location of an aneurysm. When placed around the outside of a vessel, is used to restrict and/or constrict the aneurysm containing portion of the vessel. If desired, the sleeve may be constructed as a double-walled sleeve that can be inflated to apply pressure to and/or in the vessel.

Abstract: Implantable medical endoprosthesis delivery systems and articles are provided.

Abstract: An apparatus for treating regurgitation of blood through a diseased heart valve having at least two leaflets includes a lollipop-shaped body member having a proximal end portion, a distal end portion, and an intermediate portion extending between the end portions. The intermediate portion includes an expandable occluding member having an adjustable diameter so that, during at least a portion of the cardiac cycle, at least one of the heart leaflet coapts with a portion of the occluding member to mitigate or prevent regurgitation of blood through the diseased heart valve. The proximal end portion is physically connected to the occluding member and includes a connecting mechanism for operably mating with an adjustment member for adjusting the position and diameter of the occluding member within the diseased heart valve. The distal end portion includes an anchoring member for securing the apparatus in a heart chamber containing the diseased heart valve.

Abstract: A medical prosthesis having a low profile for delivery into a body lumen is disclosed. The stent includes a plurality of wire strands woven to form a plurality of joints at the intersections, some of which are helically wrapped. The helically wrapped joints may be offset form the joints of a second plurality of wire strands concentric to the first. Alternatively, the helically wrapped joints can doubled forming box nodes.

Abstract: The present invention provides an aortic valvuloplasty catheter which, in one preferred embodiment, has a tapered distal balloon segment that anchors within the left ventricle outflow track of the patient's heart and a rounded proximal segment which conforms to the aortic sinuses forcing the valve leaflets open. In addition, this embodiment of the valvuloplasty catheter includes a fiber-based balloon membrane, a distal pigtail end hole catheter tip, and a catheter sheath.

Abstract: Medical device delivery systems that include a distal protection feature are provided. A distal tip member that includes a distal protection device and a mounting region for a self-expandable, intraluminal medical device is slidably disposed within a passageway defined by a tubular member.

Abstract: Devices, systems, and methods for controlling local blood pressure. In an exemplary embodiment of a device for exposing a blood vessel to increased pressure of the present disclosure, the device comprises an anchor configured for placement into a blood vessel and to expand independently from a particle held from flowing away by the anchor, the particle configured to gradually expand due to exposure to blood flow.

Abstract: A stent delivery device includes a distal-side tube having a guide wire lumen; a proximal-side tube whose distal portion is fixed to a proximal portion of the distal-side tube; a cylindrical member which encloses a distal side of the distal-side tube and is slidable toward a proximal end of the distal-side tube; a stent accommodated in the cylindrical member; and a pulling member 6 for moving the cylindrical member toward a proximal side of the stent delivery device. The distal-side tube has a proximal-side opening which is open at the proximal side of the distal-side tube; and a stent-locking portion for preventing the stent from moving to the proximal side of the stent delivery device. The outer diameter of the proximal-side tube is set smaller than that of a portion, having a maximum diameter, which is disposed in a region of the stent delivery device which is distal from the proximal-side tube.

Abstract: A medical device detachment system receives an elongate delivery member, having a lumen, and an elongate core member. The system includes a housing, a user input mechanism for receiving a user input to effect detachment of a medical device, such as an embolic coil, from a distal end of the delivery member, and a grasping mechanism for grasping and moving a proximal end of the core member relative to a proximal end of the delivery member. The system also includes a first sensor detecting positioning of the proximal end of the core member within the housing, and a second sensor, detecting movement of the grasping mechanism. An indicator is connected to the first and second proximity sensors and provides feedback to a user.

Abstract: A method for facilitating treatment of catheter induced vascular injuries may first involve introducing a guide wire into a vascular sheath residing in a blood vessel, where the guide wire has a distal end and an inflatable balloon at least 15 cm proximal of the distal end. The method may further involve proximally retracting the vascular sheath while leaving the wire in place and observing indicia of the presence or absence of a vascular injury caused to the blood vessel by the vascular sheath or a procedural catheter previously advanced through the vascular sheath. If indicia of a vascular injury are observed, the method may involve positioning the inflatable balloon at or near the vascular injury and inflating the balloon to reduce blood flow past the vascular injury, while leaving the guide wire in place to provide subsequent access to the injury.

Abstract: A new endoluminal prosthesis for use in sealing a vascular graft to corporeal lumen provides for a flattened bulbous tail at the end of each cell of the prosthesis. The flattened bulbous tails reduce the amount of wear between the prosthesis and the softer material of the vascular grafts or corporeal lumen walls. A method of manufacturing a stent from a flat sheet of material is also included.

Abstract: A method of reducing the risk of clinical sequelae to catheter induced vascular injuries may include introducing a guide wire into a vascular sheath residing in a blood vessel, proximally retracting the vascular sheath while leaving the wire in place, and observing indicia of the presence or absence of a vascular injury caused to the blood vessel by the vascular sheath or a procedural catheter previously advanced through the vascular sheath. If indicia of a vascular injury are observed, the method may further involve proximally retracting the guide wire to position the inflatable balloon adjacent the injury and inflating the balloon to reduce blood flow past the injury, while leaving the guide wire in place to provide subsequent access to the injury.

Abstract: Devices, systems and methods are provided for performing implantation procedures in a desired area of the body. Systems include embodiments of medical implants that include scaffold and inflatable portions and delivery systems to position and release the medical implants at a target location within the body.

Abstract: Devices, systems and methods are provided for performing implantation procedures in a desired area of the body. Systems include embodiments of medical implants that include scaffold and inflatable portions and delivery systems to position and release the medical implants at a target location within the body.

Abstract: An embolization device for occluding a body vessel cavity defined by a cavity wall is disclosed. The device includes an inflatable balloon made of a permeable material. The balloon is configured to have a deflated state and an inflated state and includes a proximal portion having an inflation hole formed therethrough to a cavity within the balloon. An inflation member is removably attached to the proximal portion and is configured to introduce a material in the cavity by way of the hole for inflation of the balloon. The permeable material is configured to allow inflation of the balloon and a portion of the solidifiable material to pass through the permeable material for contact with the cavity wall. The inflation member is configured to transmit, for example, ultra violet light to cure a solidifiable material, thereby maintaining the balloon in the inflated state and to adhering the balloon to the cavity wall.

Abstract: A stent comprises a tubular flexible body composed of a web structure that is expandable from a contracted delivery configuration to a deployed configuration and that comprises neighboring web patterns of alternating concavities extending circumferentially and adjoined by X-shaped transition sections. The web pattern may comprise either arcuate struts interconnected by bends, or a plurality of substantially straight sections with the transition sections formed by the junctions between pairs of adjacent bends of opposite curvatures.

Abstract: The present invention relates to devices and methods for the treatment of diseases in the vasculature, and more specifically, devices and methods for treatment of aneurysms found in blood vessels. In a first embodiment of the present invention, a two part prostheses, where one part is an expandable sponge structure and the other part is an expandable tubular mesh structure, is provided. In the first embodiment, the expandable sponge structure is intended to fill the aneurysm cavity to prevent further dilatation of the vessel wall by creating a buffer or barrier between the pressurized pulsating blood flow and the thinning vessel wall. In the first embodiment, the expandable tubular mesh structure is placed across the aneurysm, contacting the inner wall of healthy vessel proximal and distal to the aneurysm.

Abstract: The present invention embodies an endovascular graft having an attachment frame connection mechanism that allows placement of the main body component in vasculature in combination with limb components. Various limb component-to-main body component attachment mechanisms are provided which ensure a reliable bond while facilitating a smaller delivery profile.

Abstract: A vaso-occlusive device delivery system includes a delivery wire assembly having a core wire disposed in a delivery wire lumen, and a vaso-occlusive device having a tapered proximal end and defining a vaso-occlusive device lumen, wherein a tether is disposed in the lumen and secured to the core wire. A link may be attached to each of the core wire, the proximal end of the vaso-occlusive device, and the tether. Alternatively, the system may include a transition member attached to the vaso-occlusive device and secured to the core wire.

Abstract: The methods and devices disclosed herein pertain to the percutaneous treatment of various forms of aortic dissection by at least partially filling the false lumen of the aortic dissection with a stabilization agent percutaneously and steps to decrease the size of the false lumen using the devices. Fluid maybe aspirated from the false lumen to decrease the volume of the false lumen. And the entrance opening between the true lumen and the false lumen may be sealed with a sealing agent such as a biocompatible adhesive. The medical devices disclosed herein generally comprise an extendable sealing element that is used in conjunction with a catheter to expand the true lumen while reducing the size of the false lumen. The device has the ability to aspirate and/or deliver fluid containing the stabilization agent into the false lumen.

Abstract: The present invention relates to a medical prosthesis having a low profile for delivery into a body lumen. The stent includes a plurality of geometric cells defining the stent, which has first and second opposed open ends; and a plurality of wire strands woven to form a plurality of crossed regions defining the geometric cells. Each wire strand has strand ends and the strand ends are disposed at the second end of the stent.

Abstract: Aneurysms are treated by filling a double-walled filling structure with a curable medium. The structures may be delivered over balloon deployment mechanisms in order to shape and open tubular lumens therethrough. The filling structures are preferably used in pairs for providing flow into the iliac arteries when treating abdominal aortic aneurysm.

Abstract: The present invention provides a system and a method for forming in vivo a junction between a first and a second element of a modular endovascular prosthesis used for repairing defects in vessels and other lumens within the body of a patient. The first element is adapted to have a receiving element, and the second element is adapted to have a protruding element. In the final deployed configuration of the endovascular prosthesis, the protruding element of the second element is adapted to be engaged with the receiving element of the first element, substantially preventing axial separation of the elements relative to each other. The receiving element of the invention may have various forms, and may include a fold in the wall of the first element, an expandable framework having protruding struts, or a flexible thread.