A thrombectomy apparatus for removing a clot from a vessel includes a catheter defining a lumen extending proximally from a distal end. A funnel is secured to the distal end and extends distally therefrom, the funnel includes a braided inner layer and a braided outer layer, the braided outer layer folded over the braided inner layer and adapted to constrain the braided inner layer. A tractor is adapted to extend over an outer surface of the catheter and the funnel in an un-inverted configuration and to extend in an inverted configuration through the funnel and into the lumen, the tractor adapted to invert by rolling over the distal end of the funnel when the tractor moves proximally. A puller extends through the lumen and is secured to an end of the tractor disposed within the lumen.

TECHNICAL FIELD

The present disclosure relates generally to medical devices. More particularly, the present disclosure pertains to medical devices for performing thrombectomy procedures.

BACKGROUND

A wide variety of intracorporeal medical devices have been developed for medical use, for example, intravascular use. Some of these devices include thrombectomy apparatuses. These devices are manufactured by any one of a variety of different manufacturing methods and may be used according to any one of a variety of methods. Of the known medical devices and methods, each has certain advantages and disadvantages. There is an ongoing need to provide alternative medical devices as well as alternative methods for manufacturing and using medical devices.

SUMMARY

The disclosure is directed to design, material, manufacturing method, and use alternatives for thrombectomy apparatuses. An example may be found in a thrombectomy apparatus for removing a clot from a vessel. The thrombectomy apparatus includes a catheter having a distal region including a distal end, the catheter defining a lumen extending proximally from the distal end, the catheter having an outer surface. A funnel is secured to the distal end and extends distally therefrom, the funnel includes a braided inner layer and a braided outer layer, the braided outer layer folded over the braided inner layer and adapted to constrain the braided inner layer. A tractor is adapted to extend over the outer surface of the catheter and the funnel in an un-inverted configuration and to extend in an inverted configuration through the funnel and into the lumen, the tractor adapted to invert by rolling over the distal end of the funnel when the tractor moves proximally within the lumen. A puller extends through the lumen and is secured to an end of the tractor disposed within the lumen.

Alternatively or additionally, the tractor may be adapted to engage the clot and pull the clot proximally into the funnel as the tractor inverts over the distal end of the funnel.

Alternatively or additionally, the tractor may include a flexible tube having a plurality of loops that lie flat before reaching the distal end of the catheter and after passing the distal end of the catheter, but temporarily extend radially outwardly as the tractor inverts over the distal end of the catheter, the plurality of loops temporarily extending radially outward as the tractor inverts over the distal end of the catheter engage the clot and pull the clot proximally.

Alternatively or additionally, the braided outer layer may be adapted to constrain against the braided inner layer expanding radially as a result of axial compression as the tractor is pulled over the distal end of the funnel.

Alternatively or additionally, the braided inner layer may have a first braid angle, the braided outer layer may have a second braid angle, and the second braid angle may be greater than the first braid angle.

Alternatively or additionally, the funnel may be formed from a unitary braided member folded over on itself, the braided inner layer including a first portion of the unitary braided member and the braided outer layer including a second portion of the unitary braided member.

Alternatively or additionally, the braided outer layer may include additional filaments.

Alternatively or additionally, the braided outer layer may include some single filaments extending both clockwise and counterclockwise and some double filaments extending both clockwise and counterclockwise.

Alternatively or additionally, the braided outer layer may include about half single filaments extending both clockwise and counterclockwise and about half double filaments extending both clockwise and counterclockwise.

Alternatively or additionally, the braided inner layer may not include any additional filaments.

Alternatively or additionally, the braided outer layer includes a varying PPI count along its length.

Alternatively or additionally, the braided inner layer comprises a constant PPI count along its length.

Another example may be found in a thrombectomy apparatus for removing a clot from a vessel. The thrombectomy apparatus includes a catheter having a distal end and a lumen extending proximally from the distal end, and a funnel extending distally from the distal end. The funnel includes a braided inner layer and a braided outer layer, the braided outer layer folded over the braided inner layer and adapted to constrain the braided inner layer. A tractor is adapted to extend outside the catheter and funnel in an un-inverted configuration and to extend in an inverted configuration into an interior of the funnel, the tractor adapted to invert by rolling over the distal end of the funnel when the tractor is pulled proximally within the lumen.

Alternatively or additionally, the braided inner layer may have a first braid angle, the braided outer layer may have a second braid angle, and the second braid angle may be greater than the first braid angle.

Alternatively or additionally, the funnel may be formed from a braided member folded over on itself, the braided inner layer including a first portion of the braided member and the braided outer layer including a second portion of the braided member.

Alternatively or additionally, the braided outer layer may include additional filaments.

Alternatively or additionally, the braided outer layer may include some single filaments extending both clockwise and counterclockwise and some double filaments extending both clockwise and counterclockwise.

Alternatively or additionally, the braided outer layer may include about half single filaments extending both clockwise and counterclockwise and about half double filaments extending both clockwise and counterclockwise.

Alternatively or additionally, the braided outer layer includes a varying PPI count along its length.

Another example may be found in a thrombectomy apparatus for removing a clot from a vessel. The thrombectomy apparatus includes a catheter having a distal end and a lumen extending proximally from the distal end. A funnel extends distally from the distal end. The funnel includes a braided inner layer having a first braid angle and a braided outer layer having a second braid angle, the braided outer layer folded over the braided inner layer, the second braid angle greater than the first braided angle. A tractor is adapted to extend outside the catheter and funnel in an un-inverted configuration and to extend in an inverted configuration into an interior of the funnel, the tractor adapted to invert by rolling over the distal end of the funnel when the tractor is pulled proximally within the lumen.

DESCRIPTION

The following description should be read with reference to the drawings, in which like elements in different drawings are numbered in like fashion. The drawings, which are not necessarily to scale, depict examples that are not intended to limit the scope of the disclosure. Although examples are illustrated for the various elements, those skilled in the art will recognize that many of the examples provided have suitable alternatives that may be utilized.

Thrombectomy is a process whereby a thrombus, or clot, is removed from within a blood vessel.FIG.1is a schematic view of an illustrative thrombectomy apparatus10that is shown positioned within an example blood vessel12. A thrombus or clot14is schematically shown within the blood vessel12. The thrombectomy apparatus10includes a catheter16that extends from a proximal region18to a distal region20and includes a distal end22. A lumen24extends through the catheter16. The catheter16includes an outer surface26. A funnel28is secured to the distal end22and extends distally from the distal end22. In some instances, the funnel28is a braided structure including a braided inner layer and a braided outer layer, as will be shown in subsequent drawings. As will be discussed, in some instances the braided outer layer may be adapted to constrain the braided inner layer from expanding too far in a radially outward direction as a result of an axial compressive force.

A tractor30is adapted to extend over the outer surface26of the catheter16and the funnel28in an un-inverted configuration and to extend in an inverted configuration through the funnel28and into the lumen24. In some instances, the tractor30may be adapted to invert by rolling over a distal end32of the funnel28when the tractor30moves proximally through the lumen24. It will be appreciated that a portion of the tractor30within the lumen24, the inverted portion, moves proximally while another portion of the tractor30, outside of the catheter16, move distally. The thrombectomy apparatus10includes an elongate member34that extends through the lumen24and is operably coupled with an end36of the tractor30that is disposed within the lumen24. In some instances, the tractor30is adapted to engage the clot14and to pull the clot14proximally into the funnel28and thus into the lumen24as the tractor30inverts over the distal end32of the funnel28.

The thrombectomy apparatus10includes an elongate member34that is adapted to extend through the lumen24within the catheter16. The elongate member34is secured to the end36of the tractor30that is disposed within the lumen24. In some instances, the elongate member34may be a catheter. In some instances, the elongate member34may be a pull wire or other pull member that is flexible enough to bend within the lumen24as the catheter16navigates the vasculature, but strong enough to allow a user to pull the elongate member34proximally in order to pull the tractor30proximally into the funnel28and thus into the lumen24. In some instances, the elongate member34may be adhesively secured to the tractor30. In some instances, the elongate member34may be welded to the tractor30.

In some instances, the thrombectomy apparatus10may include a sheath38. The sheath38may overly the catheter16and the tractor30. In some instances, the sheath38helps prevent the tractor30from engaging or otherwise contacting the walls of the blood vessel12. In some instances, the sheath38may have an inner diameter sufficient to prevent the tractor30from engaging the walls of the blood vessel12while still allowing the tractor30to move relative to the outer surface26of the catheter16as the tractor30moves. In some instances, the sheath38or at least an inner layer or coating may be formed of a lubricious material such as but not limited to a fluoropolymer. As an example, the sheath38may be formed of, or may at least have an inner layer or coating that is formed of a fluoropolymer such as polytetrafluoroethylene (PTFE), commonly known as Teflon®.

In some instances, the sheath38may be positioned further distally relative to the funnel28during advancement of the thrombectomy apparatus10through the vasculature. In some instances, the sheath38may constrain the funnel28into a smaller diameter configuration while the thrombectomy apparatus10is advanced through the vasculature. Once a desired location has been reached, the sheath38may be withdrawn proximally a short distance in order to allow the funnel28to expand into a conical shape, as shown. Prior to subsequent removal of the thrombectomy apparatus10, the sheath38may be advanced distally a short distance in order to once again collapse the funnel28into a smaller diameter configuration for navigation.

As noted,FIG.1shows the thrombectomy apparatus10positioned within the blood vessel12, with the distal end32of the funnel28positioned adjacent or even in contact with the clot14. By withdrawing the elongate member34proximally, the tractor30is caused to move over the distal end32of the funnel28, and to pass through an interior of the funnel28and into the lumen24. In some instances, as the tractor30moves from an un-inverted configuration proximal of the distal end32of the funnel28, to an inverted configuration as the tractor30moves beyond the distal end32of the funnel28, the tractor30is adapted to grab the clot14and to pull the clot14into the funnel28and into the lumen24. The culmination of this may be seen inFIG.2, which shows the thrombectomy apparatus10in a finishing position in which the clot14has been completely pulled into an interior of the thrombectomy apparatus10. As can be seen inFIG.2, the clot14is positioned within the lumen24and within the funnel28. At this point, withdrawal of the thrombectomy apparatus10means that clot14will have been removed from the patient.

It will be appreciated that the clot14has a length when disposed within the blood vessel12. In some instances, during the process of capturing the clot14, the thrombectomy apparatus10will move distally. In some instances, the thrombectomy apparatus10will move distally a distance about equal to the length of the clot14when the clot14is still in the blood vessel12. If the undisturbed clot14has a length of 12 centimeters, the thrombectomy apparatus10may move distally a distance of about 12 centimeters in the process of capturing the clot14. In some instances, depending on the nature of the clot14, the thrombectomy apparatus10may move distally a distance greater than the length of the undisturbed clot14, for example.

FIG.3is a schematic view of the tractor30disposed over the funnel28. In some instances, as shown, the tractor30may be formed from a plurality of loops40. In some instances, the tractor30may be formed by knitting one or more filaments42into the plurality of loops40. A variety of different knitting patterns may be utilized, for example. It will be appreciated that the portion of the tractor30shown outside of the funnel28is in an un-inverted configuration while the portion of the tractor30inside the funnel28(not visible) is in an inverted configuration. The tractor30inverts from the un-inverted configuration to the inverted configuration as the tractor30moves around the distal end32of the funnel28. With particular attention to a specific loop44, it can be seen that the loop44has a leading edge46and a trailing edge48. As the loop44pivots around the distal end32of the funnel28, the leading edge46moves in a direction indicated by an arrow50while the trailing edge46moves in a direction indicated by an arrow52. Accordingly, as each of the loops44pivot around the distal end32of the funnel28, each loop44will temporarily extend radially outwardly as the loop44pivots. Otherwise, each of the loops44will lay flat, particularly as tension is placed on the tractor30. Additional details regarding the thrombectomy apparatus10, including the catheter16, the tractor30and the elongate member34, may be found in U.S. Pat. Nos. 9,962,178; 10,835,269; US 2022/0257269 and US 2022/0287053, each of which are incorporated by reference herein.

It will be appreciated that as the tractor30is pulled into the funnel28and into the lumen24by withdrawing the elongate member34proximally, and as a result the tractor30inverts over the distal end32of the funnel28, that an axial compressive force is applied to the funnel28by the tractor30. In some instances, the funnel28may be adapted to resist or otherwise accommodate this axial compressive force such that the funnel28is able to retain its tapered shape. In some instances, as will be discussed, the funnel28may be a braided structure. Braided structures can have a tendency to increase in diameter in response to a decrease in length, and of course the inverse is true as well. A braided structure can have a tendency to decrease in diameter in response to an increase in length. In some instances, the funnel28may be a braided structure having an inner braided layer and an outer braided layer. In some instances, the outer braided layer may be adapted to constrain the inner braided layer from radially expanding too far in response to an applied axial force. The resulting composite structure, including the inner braided layer and the outer braided layer, may be considered as a conflicting braid funnel.

FIG.4is a schematic view of an illustrative braided member60that may be used in forming the funnel28. It will be appreciated that the braided member60is illustrated two-dimensionally, even though the braided member60is actually a three dimensional construct. The braided member60may be considered as including a first portion62that will ultimately form an outer braid layer and a second portion64that will ultimately form an inner braid layer. The braided member60may be considered as being a unitary or continuous braid, with the individual filament or filaments forming the braided member60extending continuously through both the first portion62and the second portion64. In some instances, the braided member60will undergo a change in braid angle at a fold location65. In some instances, the braided member60may additionally or alternatively undergo a change in diameter at the fold location65. For example, the second portion64may be formed to have a smaller diameter than the first portion62, which may facilitate forming a dual layer braided structure as the second portion64ultimately is manipulated into an interior of the first portion62.

As shown, the first portion62has a braid angle indicated as a (alpha) and the second portion64has a braid angle indicated as β (beta). As can be seen, the braid angle α (alpha) is larger than the braid angle β (beta). In some instances, the braid angle α (alpha) may be at least five percent or more greater than the braid angle β (beta). In some instances, the braid angle α (alpha) may be at least ten percent or more greater than the braid angle β (beta). In some instances, the braid angle α (alpha) may be at least fifteen percent or more greater than the braid angle β (beta). In some instances, the braid angle α (alpha) may be at least twenty percent or more greater than the braid angle β (beta). In some instances, the braid angle α (alpha) may be in a range of 90 to 150 degrees while the braid angle β (beta) may be in a range of 90 to 140 degrees, with the caveat that the braid angle α (alpha) is larger than the braid angle β (beta). As an example, the braid angle α (alpha) may be about 135 to 145 degrees while the braid angle β (beta) may be about 115 degrees to about 125 degrees. Because the first portion62has a higher braid angle, the first portion will not radially expand in response to an applied axial force as much as the second portion64will. Because the first portion62will form the outer braided layer, the first portion62can be seen as constraining the second portion64(which will form the inner braided layer) from expanding as much as the second portion64would otherwise expand in response to an applied axial force.

In order to form the funnel28, the braided member60may be manipulated such that the second portion64is disposed inside of the first portion62. In some instances, this may include pushing the second portion64inside of the first portion62. In some instances, this may include folding the first portion62over on top of the second portion64. As noted, the first portion62will form the outer braided layer and the second portion64will form the inner braided layer. This may be seen inFIG.5, which shows the braided member60with an outer braided layer66that corresponds to the first portion62and an inner braided layer68that corresponds to the second portion64.

FIG.6shows the funnel28in finished form. The funnel28includes a cuff70that holds the inner braided layer68in a conical shape. The cuff70may be a polymeric sleeve, for example. In some instances, the braided member60as shown inFIG.5may be compressed into a conical shape in forming the funnel28. To an extent,FIG.6may be considered as being schematic in nature becauseFIG.6does not show the compression that will occur in the smaller diameter portions of the funnel28as the braided member60(FIG.4) is compressed into the ultimate conical shape of the funnel28. The outer braided layer66will constrain the inner braided layer68from radially expanding too far as a result of the applied axial force from the tractor30being pulled into the funnel28.

In some instances, compressing the braided member60down into the funnel28results in the braid angles being reduced in the smaller diameter portions of the funnel28. As an example, the funnel28may taper from an maximum outer diameter measured at the mouth of the funnel28of about 10 millimeters to a minimum outer diameter measured at the end opposing the mouth of the funnel28of about 4 millimeters. If left unconstrained, the 4 millimeter diameter portion of the braid could expand out to about 10 millimeters. In some instances, the braided member60may be modified such the braided member60achieves the desired conical shape when undergoing an axial tensile force.

In some instances, the braiding pattern used to form the braided member60may provide a varying PPI in order to limit the maximum expansion diameter of the braided member60. In some instances, at least the outer braided layer may be modified in this way. The inner braided layer may be, but even if the inner braided layer is not modified in this way, the outer braided layer that is modified to form the desired conical funnel shape under compression will limit the radial expansion of the inner braided layer. This may be achieved, for example, by braiding on a shaped mandrel with a single PPI count programmed. This may be achieved, for example, by braiding on a tubular mandrel with a varying PPI count.

FIG.7is a schematic view of an illustrative outer braided layer80formed from a braiding pattern having a varying PPI such that the outer braided layer80maintains a constant braid angle from a proximal end82to a distal end84of the outer braided layer80when compressed. In particular, the outer braided layer80has a constant large braid angle, as indicated at86. The large braid angle86indicates that the outer braid layer80has been compressed to its limit, meaning that the outer braid layer80is at its maximum radial expansion diameter. As a result, the outer braid layer80is able to constrain an inner braid layer (not shown) from radially expanding too far.

In some instances, the funnel28may be formed from a braided outer layer that includes additional filaments. For example, the funnel28may be formed from a braided outer layer in which some of the windings are formed from single filaments while others of the windings are formed from double or triple filaments, for example. The braided outer layer may include some single filaments that extend both clockwise and counterclockwise and some double filaments extending both clockwise and counterclockwise. The braided outer layer may include about half single filaments extending both clockwise and counterclockwise and about half double filaments extending both clockwise and counterclockwise. In some instances, adding additional filaments to the braided outer layer can help the braided outer layer resist radial expansion as a result of being compressed, and thus can help constrain an inner braided layer of the funnel28.

FIG.8is a schematic illustration of a braiding pattern90that may be used in forming a braided outer layer of the funnel28. The same braiding pattern90may be utilized in forming an braided inner layer of the funnel28. In some instances, the braiding pattern90may be used in forming a braided outer layer of the funnel28while another braiding pattern (not shown) may be used in forming a braided inner layer of the funnel28. In the braiding pattern90, half of the windings in the clockwise direction are single filaments and half of the windings in the counterclockwise direction are single filaments. Half of the windings in the clockwise direction are double filaments and half of the windings in the counterclockwise direction are double filaments. To illustrate, in a first direction (as clockwise and counterclockwise are dependent upon viewing position) a winding92is a single filament, a winding94is a double filament and a winding96is a single filament. In an opposing direction, a winding98is a single filament, a winding100is a double filament, and a winding102is a single filament.

FIGS.9and10are schematic views of an illustrative funnel110undergoing compressive testing. The funnel110includes 50 percent additional filaments in both the braided inner layer and the braided outer layer of the funnel110. The funnel110is secured to a shaft112, and can be seen as being compressed against a rigid surface114. InFIG.9, the funnel110is in contact with the rigid surface114, but is not yet under compression. InFIG.10, the funnel110is under compression. This can be seen by noting that inFIG.9, the funnel110has an overall length of about 20 millimeters, while inFIG.10the funnel110has an overall length of about 16 millimeters. It can be seen by comparingFIG.9andFIG.10that while the funnel110has shortened axially and increased in diameter radially, the funnel110has retained its conical shape.

FIG.11is a graphical representation of experimental results from illustrative funnels undergoing compressive testing. The results compare a control, labeled as nominal, with a total of 9 other funnels that were tested to maximum failure. The control did not have any extra filaments, while the other tested funnels each had 50 percent double filaments. The control failed at a compression of 0.9 kilograms while the inventive funnels failed at compression values ranging from 1.37 kilograms to 2.1 kilograms. As can be seen, using 50 percent double filaments provides a considerable benefit to how well the funnel withstands compressive forces.

The materials that can be used for the various components of the thrombectomy apparatus, and the various elements thereof disclosed herein may include those commonly associated with medical devices. For simplicity purposes, the following discussion refers to the thrombectomy apparatus. However, this is not intended to limit the devices and methods described herein, as the discussion may be applied to other elements, members, components, or devices disclosed herein. In some instances, the thrombectomy apparatus, and/or components thereof, may be made from a metal, metal alloy, polymer (some examples of which are disclosed below), a metal-polymer composite, ceramics, combinations thereof, and the like, or other suitable material.

Having thus described several illustrative examples of the present disclosure, those of skill in the art will readily appreciate that yet other examples may be made and used within the scope of the claims hereto attached. It will be understood, however, that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size, arrangement of parts, and exclusion and order of steps, without exceeding the scope of the disclosure. The disclosure's scope is, of course, defined in the language in which the appended claims are expressed.