AN EXTENDABLE, RETRIEVABLE ENDOVASCULAR ELEMENT

Abstract

An endovascular assembly of a guidewire having two stoppers and a deformable element having a deformable basket/braid and two sliders sliding over the guide wire. The distance between the stoppers is smaller than the distance between the sliders so that when the stoppers each engages a slider, the deformable basket is thicker than its rest shape. In one embodiment, the distance between the stoppers may be altered to facilitate e.g. retrieval of the assembly.

Claims

1. An endovascular assembly comprising: an elongate element having a proximal end and a distal end, a deformable element having a proximal slider and a distal slider configured to slide along the elongate element, the distal slider being positioned closer to the distal end than the proximal slider, the deformable element: having a rest shape where a first distance exists between the proximal slider and the distal slider along a predetermined direction, the deformable element, in the rest shape, defining a first circumscribed circle with a first radius, in a plane perpendicular to the predetermined direction, being extendable along the predetermined direction to a extended shape where a second distance exists between the proximal slider and the distal slider along the predetermined direction, the second distance exceeding the first distance, the deformable element, in the extended shape, defining a second circumscribed circle with a second radius, in the plane perpendicular to the predetermined direction, the first radius exceeding the second radius, being compressible along the predetermined direction to a compressed shape where a third distance exists between the proximal slider and the distal slider along the predetermined direction, the first distance exceeding the third distance, the deformable element, in the compressed shape, defining a third circumscribed circle with a third radius, in the plane perpendicular to the predetermined direction, the third radius exceeding the first radius, a proximal stopper fixed or fixable in relation to the elongate element, a distal stopper fixed or fixable in relation to the elongate element, where: the distal stopper is positioned closer to the distal end than the proximal stopper, the proximal stopper is positioned closer to the distal end than the proximal slider, the proximal stopper being configured to prevent the proximal slider from moving closer to the distal end than the proximal stopper, the distal stopper is positioned closer to the distal end than the distal slider, the distal stopper being configured to prevent the distal slider from moving closer to the distal end than the distal stopper, and a distance, along the elongate element, between the proximal stopper and the distal stopper is no more than a predetermined distance being 0.95*the first distance.

2. The assembly according to claim 1, wherein the proximal and distal stoppers are fixedly attached in relation to the elongate element.

3. The assembly according to claim 1, wherein the proximal stopper is configured to pass the distal slider when moved distally.

4. The assembly according to claim 1, wherein the proximal stopper is configured to engage the distal slider when moved distally.

5. The assembly according to claim 1 wherein the third distance is no more than 0.95*the first distance.

6. The assembly according to claim 1, wherein the elongate element is a single elongate element.

7. The assembly according to 1, wherein the elongate element comprises a first and a second elongate elements each having a proximal end and a distal end, wherein: the proximal slider is configured to slide along the second elongate element, the distal slider is configured to slide along the first elongate element, the proximal stopper is fixed or fixable in relation to the second elongate element, and the distal stopper is fixed or fixable in relation to the first elongate element, the assembly further comprising a locking element configured to lock the first elongate element to the second elongate element to maintain a predetermined relative longitudinal relation, along the predetermined direction, between the proximal and distal sliders.

8. The assembly according to claim 7, where the first and second elongate elements are co-extending at at least a portion of the lengths thereof, the locking element being positioned so as to lock the first elongated element to the second elongate element at a position within the portion of the lengths.

9. The assembly according to claim 8, wherein, at the portion of the lengths, the first elongate element extends within the second elongate element.

10. The assembly according to claim 7, wherein the locking element is provided at the proximal end of at least one of the first and second elongate elements.

11. The assembly according to claim 7, further comprising an element configured to define a minimum distance, along the elongate element, between the proximal stopper and the distal stopper.

Description

[0108] In the following, preferred embodiments of the invention will be described with reference to the drawing, wherein:

[0109] FIG. 1 illustrates a first embodiment of an assembly according to the invention where the deformable element is in its rest shape,

[0110] FIG. 2 illustrates the first embodiment of FIG. 1, where the deformable element is compressed,

[0111] FIG. 3 illustrates a second embodiment of an assembly according to the invention where the deformable element is in its rest shape,

[0112] FIG. 4 illustrates the second embodiment of FIG. 2 where the deformable element is compressed,

[0113] FIG. 5 illustrates the second embodiment of FIG. 2, where the distal stopper is pushed distally,

[0114] FIGS. 6-8 illustrate one manner of deploying an assembly according to the invention within a blood vessel,

[0115] FIGS. 9-12 illustrate a manner of retrieving an assembly according to the second embodiment of the invention,

[0116] FIGS. 13 and 14 illustrate different manners of providing an assembly suitable as an endovascular filter,

[0117] FIG. 15 illustrates an embodiment where the elongate elements co-extend within a third elongate element, and

[0118] FIGS. 16 and 17 illustrate an embodiment where a stopper has an outer thread and a slider an internal thread.

[0119] In FIG. 1, an assembly 100 is illustrated having an elongate guidewire 101 having a proximal end (not illustratedfar to the left) and a distal end (not illustratedfurther to the right). Stoppers 102 and 103 are attached to the guidewire 101 at positions to be described further below.

[0120] In the present context, a guidewire may be any type of elongate element. The guidewire may be solid or hollow, be defined by one or more strands/wires, wound/braided/coiled or not, and/or as a tube, such as an extruded tube.

[0121] A sheath, in this context, is an elongate, hollow element through which a guidewire may be guided if desired. Also or alternatively, the sheath may be used for transporting liquid/gas.

[0122] The sheath may be formed as a tube, a hypotube, a coil or the like, and the sheath may comprise one or more channels therein for guiding a guidewire/liquid or the like.

[0123] The guidewire and sheath may or may not have a desired shape, such as by use of a memory shape material, such as an alterable shape as known for negotiating the way through blood vessels.

[0124] Any one of the guidewire and sheath may have a hydrophilic surface. Also, a soft, atraumatic tip may be provided to one or both of the guidewire and sheath to aid in guiding of the assembly within the blood vessel(s). The guidewire 101 travels through a deformable element 150 having sliders 104 and 105 at either end, an engaging surface 152 configured to engage a blood vessel 94 wherein the deformable element 150 is deployed. Between the engaging surface 152 and the sliders 104/105, tapering elements 151/153 are provided.

[0125] The deformable element 150 may have multiple functions in the blood vessel 94. One function is that of a filter configured to allow blood flow there through but to retain embolic material from e.g. surgery or angioplasty performed upstream of the position of the filter. Another function is that of occluding the blood vessel, where the deformable element may have a surface or an element configured to prevent blood through the deformable element. A further or additional function may be that of fixing itself to the blood vessel to fix the position or the presence of the guidewire in the blood vessel. Literature describing these different types of uses or functions is mentioned further above.

[0126] The deformable element may be provided or generated in a number of manners. In one situation, the deformable element is formed as a braid of a number of braided, elongate elements, such as wires (e.g. NiTiNol or other biocompatible materials). Alternatively, the deformable element may be formed by cutting a tube, such as a hypotube, along elongated lines whereby, upon compressing the hypotube along the longitudinal direction, the resulting, elongate elements will bulge outwardly and thus form a deformable element.

[0127] The deformable element may be basket-shaped as illustrated or rather shaped as a parachute with support wires (from which the person hanging in the parachute hangs) and having at one end the top of the parachute, and at another end, an element where the support wires are attached. The parachute will typically engage the blood vessel at its outer parts.

[0128] Different portions of the deformable element may have different properties. Thus, if the deformable element is for use as e.g. a filter, one or both of the tapering portions 151/153 may be provided with the filtering properties (number or size of openings required for filtering) where the engaging surface may have other properties, such as for optimal engagement with the blood vessel. In the parachute example, the parachute-portion may have the filtering properties and the wires other properties.

[0129] Preferably, the deformable element is self expanding so that it, when unstressed, reaches a rest shape having a first distance between the sliders 104 and 105 and a first circumscribed circle in a plane perpendicular to the straight line through the sliders 104/105along which the guidewire 101 extends.

[0130] Usually, the deformable element of the assembly is selected to have a rest shape equal to or slightly larger than the diameter/dimensions of the blood vessel so that the deformable element in the rest shape will engage the inner side of the blood vessel. Self expansion may be obtained by providing the deformable element with the desired shape (such as on a mandrel) and subsequently treating the deformable element, such as by a heat treatment, to permanently shape the deformable element to this desired shape.

[0131] It is seen that the distance between the stoppers 102 and 103 in FIG. 1 is smaller than the distance between the sliders 104/105. Thus, when the guidewire 101 is pulled (to the left) outwardly of the blood vessel, the stopper 103 will initially contact the slider 105 and act to force the slider 105 in the same direction. This will act to compress the deformable element 150 longitudinally and thus, if the deformable element is adapted to do so, increase the diameter of the deformable element. This increases the engagement between the deformable element and the blood vessel, and this is the situation seen in FIG. 2.

[0132] In FIG. 2, the guidewire 101 has been pulled to the degree that the proximal stopper 102 engages the proximal slider 104. Clearly, pulling the guidewire 101 harder will now act to attempt to translate the assembly inside the blood vessel. Pulling the guidewire 101 harder will not increase the diameter of the circumscribed circle. Thus, pulling the guidewire 101 harder will not increase the circumscribed circle, and thus the blood vessel, further. The distance between the stoppers 102/103 thus aid in limiting a maximum force exertion of the blood vessel.

[0133] The expansion of the deformable element, thus, is desired in this embodiment. Extension may be allowed when the deformable element does not have an element limiting the diameter (such as a diameter of the circumscribed element) or circumference of the deformable element. A limiter of this type may be a non-stretchable band extending along the circumference of the deformable element in a plane perpendicular to the longitudinal direction also followed by the guidewire 101.

[0134] For example, when the deformable element comprises a braid of wires or other elongate elements extending at an angle different from perpendicular to the longitudinal direction, compression of the deformable element is possible. These wires or other elements may extend within a plane also comprising the longitudinal direction or around the longitudinal direction while having a projection along the longitudinal direction.

[0135] The deformable element may, in addition to, or instead of, such elongate elements, have additional components for providing particular properties to the deformable element. In one example (see also further below), the deformable element may comprise a sheet-like material which has openings and which forms a filtering or occluding surface. In that situation, the sheet-like material may be sufficiently pleated or sufficiently expandable/extendable to allow the compression of the deformable element.

[0136] In FIGS. 1 and 2, a thread 106 is illustrated. This thread may be used for deployment and especially retrieval of the deformable element 150 such as by using a retrieval catheter engaging the thread 106 to pull the deformable element into a retrieval catheter via which the deformable element may be removed from the blood vessel. In FIGS. 9-12, another retrieval method is described.

[0137] It is seen that when providing two sliders, the guidewire 101 may be translated or pushed further into the blood vessel. The stopper 102 may, upon pushing, engage the slider 105 (see the equivalent operation in FIG. 6 and as described below) whereby the deformable element may be pushed further into the blood vessel or push the element 150 out of a delivery sheath. Alternatively, the stopper 102 may be adapted to be translated through the slider 105 (either by e.g. having an outer diameter smaller than an inner diameter of the slider 105 or by having an outer thread adapted to an inner thread of the slider 105 so that rotation may bring the stopper 102 through and then distally of slider 105), so that the guidewire 101 may be translated as far into the blood vessel as desired without affecting the position of the deformable element.

[0138] In FIG. 1, a tube or slider 110 is illustrated which may be used to alter the interaction or method of the assembly. The tube/slider 110 alters the effective distance between the stoppers 102/103 in that it effectively alters the position of the surface engaging the slider 104 from the proximal surface of the stopper 102 to that of the tube 110. Thus, it is seen that the distance between the sliders 105/104, when both being engaged by the stoppers 102/103now via the tube 110is larger. Thus, a lower compression is allowed by the element 150 before the compression is stopped.

[0139] The use of a tube/slider 110 may thus be used for changing the characteristics of an assembly. An alternative would be to change the positions of the stoppers and/or change the shape of the element 150 which is a more expensive and labour consuming step.

[0140] Naturally, the element 110 may optionally or additionally be positioned between the distal slider 105 and the distal stopper 103.

[0141] Providing a set of assemblies as seen in FIG. 1 and one or more tubes, of different lengths, would equate providing different assemblies with different distances between the stoppers and/or different shapes of elements 150such as different distances between the sliders in the rest position.

[0142] In FIGS. 3-5, a second embodiment of an assembly 200 according to the invention is illustrated. This embodiment has two stoppers 202/203 and the deformable element 250 with sliders 204/205, an engagement portion 252 and tapering portions 251/253.

[0143] In the assembly 200, an inner guidewire 211 is provided co-extending within an outer sheath 201, where the stopper 203 is fixed to or in relation to the inner guidewire 211 and the stopper 202 is fixed to or in relation to the sheath 201. It is noted that this co-extending is not absolutely required and that the guidewire and sheath may be provided not inside each other and be guided to the deformable element 250 along two different routes, but this is usually very inconvenient.

[0144] In one embodiment, the set of guidewire and sheath may be a movable core guidewire as is known in the art.

[0145] In FIG. 15, as an alternative, two elongate elements 211 and 211 extend within a common sheath 201.

[0146] Thus, when the guidewire 211 is pushed distally (to the right) in relation to the sheath 201, the stopper 203 is moved distally in relation to the stopper 202, thus increasing the distance between the stoppers 202/203.

[0147] Also, when the guidewire 211 is pulled proximally (to the left) in relation to the sheath 201, the stopper 203 is moved proximally in relation to the stopper 202, thus decreasing the distance between the stoppers 202/203.

[0148] Thus, by operating the guidewire 211 in relation to the sheath 201, the distance between the stoppers 202/203 may be defined, whereby the limits of the expansion of the deformable element 250 may be defined. Thus, the above distance being smaller than the distance corresponding to the rest position of the deformable element 250 may be selected. In fact, an indication may be provided on the guidewire or sheath illustrating this particular distance or a desired distance smaller than this particular distance.

[0149] Pulling the guidewire 211 and sheath 201 (not altering the distance between the stoppers) will, as is described above, firstly increase the size perpendicular to the longitudinal axis of the deformable element 250 but will, when the stopper 202 engages the slider 204, stop increasing the size of the deformable element.

[0150] The distance between the stoppers 202 and 203 thus defines a maximum engagement force exerted to the blood vessel when pulling the guidewire/sheath.

[0151] In FIGS. 3 and 5, an optional element 213 is illustrated which is connected to the stopper 203 and which engages the sheath 201 (but it could alternatively engage the stopper 202, slider 205 or slider 204). This element 213 defines a minimum distance between the stopper 203 and the stopper 202, when it engages, at point 210, the sheath 201. The element 213 could also engage the slider 204 if desired.

[0152] Clearly, the element 213 need not be attached to any of the sliders or stoppers and may simply freely translate between such elements. The element 213 may engage or define a minimum distance between any of, on the one side, the stopper 202, the slider 204 and the sheath 201 and, on the other side, the slider 205 and the stopper 203 or an element fixed in relation to any of the two.

[0153] An advantage of the element 213 is that the minimum distance is easily obtained, as the handle 212 may be pulled until the element 213 engages and thus provides a resistance to further pulling.

[0154] In FIG. 4, an alternative is illustrated where the element 213 has been replaced by a stopper 215 fixed to the guidewire 211.

[0155] The sheath 201 and guidewire 211 may be locked to each other at different positions. This lock may be a biasing/pressing, a snap fitting or any other type of lock. Also or alternatively, the guidewire 211 may have an outer thread engaging an inner thread in the sheath 201, so that a relative rotation may transport the guidewire 211 distally or proximally in relation to the sheath 201.

[0156] Another type of lock is indicated in FIG. 4, where an element 214 abuts the handle 212 and the proximal end of the sheath 201 so as to prevent the guidewire 211 from being translated distally in relation to the sheath 201. This lock 214 may be a clamp, a coil or other element, such as a peel-away portion of the sheath 201 or a separate peel-away portion. This lock thus may bias the handle 212 and thereby the guidewire 211 proximally in relation to the sheath 201. The lock 214 may cooperate with the above element 213 or stopper 215 to block translation of the guidewire 211, relative to the sheath 201, in both directions.

[0157] Different indications on the guidewire may be used for indicating the distance between the stoppers, the maximum outer diameter of the deformable element or the maximum force exerted on the blood vessel when the guidewire/sheath is pulled. Additionally or alternatively, the above element 213 or stopper 215 may be used for providing a tactile feedback of when the minimum distance is reached.

[0158] In FIGS. 6-8, delivery of an assembly is described. The figures are illustrated with the assembly of FIGS. 3-5, but the assembly of FIGS. 1 and 2 may equally well be used for at least some of the operations.

[0159] In FIGS. 6 and 7, a delivery catheter 260 is illustrated inside which the deformable element 250 is provided during insertion into the blood vessel. The insertion may be guided by the guidewire 211 and/or sheath 201 if desired.

[0160] When positioned correctly in the blood vessel, the guidewire/sheath is pushed distally, whereby the stopper 202 engages the slider 205 and thus forces the deformable element 250 out of the delivery catheter 260 (FIG. 6).

[0161] When fully delivered (FIG. 7), the deformable element 250 may function as described above, and the delivery catheter 260 may be removed by translation along the guidewire/sheath out of the person, where after (FIG. 8), the assembly is as described above.

[0162] In FIGS. 9-12, retrieval of an assembly as described in relation to FIGS. 3-5 is illustrated. The retrieval is performed in a retrieval catheter 260 which may be the same catheter as the above delivery catheter. The deformable element 250 may be collapsed and provided inside the retrieval catheter.

[0163] Initially (FIG. 9), the assembly is in the usual state in the blood vessel. Then, the retrieval catheter 260 is inserted (FIG. 10) and the guidewire 211 pushed distally to increase the distance between the stoppers 202/203 to allow the deformable element 250 to extend and thus be radially compressed (FIG. 11).

[0164] Then, the sheath/guidewire are pulled (together as they are locked to each other; the default situation) to force the stopper 202 in engagement/abutment with the slider 204 and pull the slider 204 and thus the element 251, then the engagement part 252 (FIG. 12) and subsequently the remainder of the deformable element 250 and the stopper 203 in to the catheter 260 which may subsequently be removed from the blood vessel.

[0165] Clearly, the radial compression of the deformable element 250 requires the deformable element to be elongated or extended, which is made possible by the increased distance between the stoppers 202/203.

[0166] In FIGS. 16 and 17 an embodiment is illustrated where the distal stopper 503 has an outer thread and the distal slider 505 of the deformable element 550 has a matching internal thread 507. Again, the deformable element has tapering portions 551 and 553 and an engaging portion 552 as well as a proximal slider engaging a proximal stopper 502 of the guidewire 501.

[0167] In FIG. 16, the threads of the stopper 503 and the slider 505 engage and rotation of the guidewire 501 in one direction may bring the stopper 503 distally of the slider 505. Rotation in the opposite direction will bring the stopper 503 proximally of the slider 505 as is seen in FIG. 17.

[0168] Thus, the distal stopper 503 may be brought into the position distally of the distal slider 505 so as to perform the above two-stopper function of limiting the extension of the deformable element 550 during pulling of the guidewire 501. Also, the stopper may be brought into the position proximally of the slider 505 to allow the deformable element to extend during pulling of the guidewire. In that manner, the deformable element is allowed to be pulled (see FIGS. 9-12) into a catheter for removal of the deformable element from the blood vessel.

[0169] In general, the deformable element 150, 250, 350, 450, 550 may be used for a plurality of purposes. In one situation, the main purpose of the deformable element is merely to fasten itself to the blood vessel to prevent accidental removal of the guidewire from the blood vessel, such as in the situation where the guidewire is to be used for guiding other endovascular elements to the blood vessel.

[0170] In another situation, the deformable element 250 the additional or optional purpose of filtering blood flowing in the blood vessel, such as for removing emboli dislodged from blood vessels upstream of the blood vessel. A filter of this type may be seen in FIG. 13, where the engagement portion 352 and the distal, tapering part 353 are provided with a filtering surface. This filtering surface may be an outer surface provided on a structure of the deformable element 350, such as a braid or the like. Alternatively, the filtering surface may be provided as a more dense part of a braid forming also the other parts of the deformable element but as a less dense portion more easily allowing both blood and emboli to pass. An advantage of providing the most distal portions of the deformable element with the filtering surface is that this surface will be inwardly tapering and thus will retain the filtered emboli when the deformable element is pulled into a retrieval catheter.

[0171] In FIG. 14, an alternative filter type may be seen where the filtering surface is provided as a separate, now inner, layer 454 provided inside the deformable element 450. The inner layer 454 may be attached to any of the tapering parts 453, 451 or the engagement portion 452. The inner layer may be a stretchable or non-stretchable layer made of e.g. a cloth (weaved, non-weaved) or a layer provided with holes/openings or a braid of e.g. nitinol wires. Again, the distally tapering shape will facilitate retaining of the emboli during retrieval.

[0172] An alternative to the filter is an occluder, which may be of the same type as seen in FIGS. 13/14 where the filtering surface is replaced with an occluding surface. Occluding surfaces may be initially closed or may comprise a coagulating agent/surface which makes the blood coagulate there on and thereby form an occluding surface.