Patent Description:
Peripheral and interventional cardiology is a medical specialty that relates to treatment of various forms of cardiovascular disease, including coronary artery disease and peripheral vascular disease. Coronary artery disease and peripheral vascular disease can arise due to the narrowing of the arteries by atherosclerosis (also called arteriosclerosis). Coronary artery disease generally affects arteries of the heart-arteries that carry blood to cardiac muscles and surrounding tissue. Peripheral vascular disease refers to various diseases of the vascular system outside the heart and brain, which carries blood, for example, to the legs.

Atherosclerosis commonly affects the medium and large arteries, and may occur when fat, cholesterol, and other substances build up on the walls of arteries and form fleshy or hard/calcified structures called plaques/lesions. As plaque forms within an arterial wall, the artery may narrow and become less flexible, which may make it more difficult for blood to flow therethrough. In the peripheral arteries, the plaque is typically not localized, but can extend in length along the axis of the artery for as much as <NUM> or more (in some instance up to <NUM> or more).

Pieces of plaque can break off and move through the affected artery to smaller blood vessels, which may in some instances block them and may result in tissue damage or tissue death (embolization). In some cases, the atherosclerotic plaque may be associated with a weakening of the wall of the affected artery, which can lead to an aneurysm. Minimally invasive surgeries may be performed to remove plaque from arteries in an effort to alleviate or help prevent the complications of atherosclerosis.

A number of interventional surgical methodologies may be used to treat atherosclerosis. In balloon angioplasty, for example, a physician may advance a collapsed, intravascular balloon catheter into a narrowed artery, and may inflate the balloon to macerate and/or displace plaque against the vessel wall. A successful angioplasty may help reopen the artery and allow for improved blood flow. Often, balloon angioplasty is performed in conjunction with the placement of a stent or scaffold structure within the artery to help minimize re-narrowing of the artery. Balloon angioplasty, however, can stretch the artery and induce scar tissue formation, while the placement of a stent can cut arterial tissue and also induce scar tissue formation. Scar tissue formation may lead to restenosis of the artery. In some instances, balloon angioplasty can also rip the vessel wall.

Atherectomy is another treatment methodology for atherosclerosis, and involves the use of an intravascular device to mechanically remove (that is, debulk) plaque from the wall of the artery. Atherectomy devices may allow for the removal of plaque from the wall of an artery, reducing the risk of stretching, cutter, or dissecting the arterial wall and causing tissue damage that leads to restenosis. In some instances, atherectomy may be used to treat restenosis by removing scar tissue.

Unfortunately, some atherectomy devices suffer from structural and performance limitations. For example, rotating cutting elements or assemblies of some atherectomy may be driven by coiled drive shafts. When such shafts are rotated in a curve of the vasculature, the coils open slightly and permit plaque and fluids to penetrate the shaft and enter an internal guide wire lumen. The plaque and fluids in the guide wire lumen increase friction between the shaft and a guide wire within the lumen, which can adversely impact device performance. Accordingly, it is desirable to provide improved atherectomy devices and methods.

<CIT>, according to its abstract, relates to a device suitable for removing material from a living being, featuring at least an aspiration pump, powered by a motor. The aspiration pump and any optional infusate pump preferably feature a helical pumping mechanism, and operate at a high rate of rotation, thereby ensuring adequate pumping performance and flexibility. The helical pumping mechanism may be a helical coiled wire about a central core tube. The helical coil wire, whether together with, or independent of, the core tube, may be rotated to cause a pumping action. Additionally, a narrow crossing profile is maintained, ensuring that the device may reach more tortuous regions of the vasculature. In one embodiment, the system comprises a wire-guided mono-rail catheter with a working head mounted on a flexible portion of the catheter that can laterally displace away from the guide wire to facilitate thrombus removal. The working head may be operated to separate and move away from the guide wire to come within a closer proximity of the obstructive material to more effectively remove it from the vessel.

<CIT>, according to its abstract, relates to devices and components for use in performing an atherectomy. The atherectomy devices may have a handle, a cutter assembly, and a catheter or catheter assembly therebetween. The cutter assembly may include a housing and a cutter comprising a proximal cutter and a distal cutter, each of which may be rotated relative to the atherectomy device to cut occlusive material.

<CIT>, according to its abstract, relates to an atherectomy device for removing deposits such as plaque from an interior of a vessel including an outer member, an inner member and a rotatable shaft positioned for rotational movement within the inner member. The outer and inner members are fixed axially. A rotatable tip is mounted to the distal region of the rotatable shaft for rotation about its longitudinal axis upon rotation of the shaft to remove deposits from the vessel.

The invention provides an atherectomy device according to claim <NUM>. Further embodiments of the invention are provided in the dependent claims. The present disclosure presents an atherectomy device for removing occlusive material from the vasculature of a subject. The atherectomy device includes a distal cutter assembly, and the cutter assembly includes a housing and a cutting element carried by the housing. The cutting element includes at least one cutting blade. The cutting element is rotatable relative to the housing to cause the at least one cutting blade to cut the occlusive material and move the occlusive material into the housing. The device further includes a catheter coupled to the distal cutter assembly. The catheter includes a sheath and a drive shaft disposed within the sheath and coupled to the cutting element. The drive shaft is rotatable relative to the sheath to rotate the cutting element relative to the housing. The drive shaft and the sheath define therebetween a material removal passageway for receiving the occlusive material from the housing. The drive shaft includes a coil having an inner lumen. A jacket is disposed outwardly of the coil, and the jacket inhibits the occlusive material in the material removal passageway from passing through the coil and entering the inner lumen.

According to the present disclosure, the jacket comprises a polymer.

According to the present disclosure, the polymer is a hydrophobic polymer.

According to the present disclosure, the hydrophobic polymer is one of polytetrafluoroethylene (PTFE) and fluorinate ethylene propylene (FEP).

According to the present disclosure, the coil is an inner coil, and further comprising an outer coil disposed outwardly from the inner coil, the outer coil being configured to proximally move the occlusive material in the material removal passageway upon rotation of the drive shaft relative to the sheath, and wherein the jacket is disposed between the inner coil and the outer coil.

According to the present disclosure, the atherectomy device further comprises an intermediate coil disposed between the inner coil and the jacket.

The present disclosure presents an atherectomy device for removing occlusive material from the vasculature of a subject. The atherectomy device includes a distal cutter assembly including a housing and a cutting element carried by the housing. The cutting element includes at least one cutting blade, and the cutting element is rotatable relative to the housing to cause the at least one cutting blade to cut the occlusive material and move the occlusive material into the housing. A catheter is coupled to the distal cutter assembly. The catheter includes a sheath that is configured to receive the occlusive material from the housing. The catheter further includes a drive shaft disposed within the sheath and coupled to the cutting element. The drive shaft is rotatable relative to the sheath to rotate the cutting element relative to the housing. The drive shaft includes an inner coil having an inner lumen and an outer coil disposed outwardly from the inner coil. The outer coil is configured to proximally move the occlusive material in a material removal passageway disposed between the drive shaft and the sheath upon rotation of the drive shaft relative to the sheath. A sealing layer is disposed between the inner coil and the outer coil. The sealing layer inhibits the occlusive material in the material removal passageway from passing through the inner coil and entering the inner lumen.

According to the present disclosure, the sealing layer comprises a polymer.

According to the present disclosure, the atherectomy device further comprises an intermediate coil disposed between the inner coil and the sealing layer.

The present invention presents an atherectomy device for removing occlusive material from the vasculature of a subject. The atherectomy device includes a distal cutter assembly including a housing and a cutting element carried by the housing. The cutting element has at least one cutting blade. The cutting element is rotatable relative to the housing to cause the at least one cutting blade to cut the occlusive material and move the occlusive material into the housing. The atherectomy device further includes a catheter coupled to the distal cutter assembly. The catheter includes a sheath that is configured to receive the occlusive material from the housing. A drive shaft is disposed within the sheath and coupled to the cutting element. The drive shaft is rotatable relative to the sheath to rotate the cutting element relative to the housing. The drive shaft includes an inner coil having an inner lumen. An outer conveyor is disposed outwardly from the inner coil. The outer conveyor is configured to proximally move the occlusive material in a material removal passageway disposed between the drive shaft and the sheath upon rotation of the drive shaft relative to the sheath. A sealing layer is disposed between the inner coil and the outer conveyor. The sealing layer inhibits the occlusive material in the material removal passageway from passing through the inner coil and entering the inner lumen.

In an embodiment of the present invention, the sealing layer comprises a polymer.

In an embodiment of the present invention, the polymer is a hydrophobic polymer.

In an embodiment of the present invention, the hydrophobic polymer is one of polytetrafluoroethylene (PTFE) and fluorinate ethylene propylene (FEP).

In an embodiment of the present invention, the atherectomy device further comprises an intermediate coil disposed between the inner coil and the sealing layer.

When each one of A, B, and C in the above expressions refers to an element, such as X, Y, and Z, or class of elements, such as X<NUM>-Xn, Y<NUM>-Ym, and Z<NUM>-Zo, the phrase is intended to refer to a single element selected from X, Y, and Z, a combination of elements selected from the same class (for example, X<NUM> and X<NUM>) as well as a combination of elements selected from two or more classes (for example, V<NUM> and Zo).

As such, the terms "a" (or "an"), "one or more" and "at least one" may be used interchangeably herein. It is also to be noted that the terms "comprising", "including", and "having" may be used interchangeably.

It should be understood that every maximum numerical limitation given throughout this disclosure is deemed to include each and every lower numerical limitation as an alternative, as if such lower numerical limitations were expressly written herein. Every minimum numerical limitation given throughout this disclosure is deemed to include each and every higher numerical limitation as an alternative, as if such higher numerical limitations were expressly written herein. Every numerical range given throughout this disclosure is deemed to include each and every narrower numerical range that falls within such broader numerical range, as if such narrower numerical ranges were all expressly written herein.

The drawings simply illustrate preferred and alternative examples of how the disclosure may be made and used and are not to be construed as limiting the disclosure to only the illustrated and described examples.

In certain instances, details that are not necessary for an understanding of the disclosure or that render other details difficult to perceive may have been omitted. It should be understood, of course, that the disclosure is not necessarily limited to the particular embodiments illustrated herein.

Before any embodiments of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter as well as additional items.

The present disclosure relates generally to devices, systems, and methods for mechanical atherectomy. Referring to <FIG>, there is shown an exemplary embodiment of the atherectomy systems described herein. The atherectomy system <NUM> includes an intravascular atherectomy device <NUM> and a guide wire <NUM> over which the atherectomy device <NUM> may be deployed. In some embodiments, the guide wire <NUM> is silicon-coated or non-coated (bare), or otherwise free of a polytetrafluoroethylene (PTFE) coating. Atherectomy systems according to some embodiments of the present disclosure comprise a guide wire <NUM> that includes a PTFE coating, or atherectomy systems according to some embodiments of the present disclosure lack a guide wire <NUM>.

With continued reference to <FIG>, the atherectomy device <NUM> generally includes a handle <NUM> and a catheter <NUM>. The handle <NUM> is configured to be grasped and manipulated by a user (for example, a medical professional) during an atherectomy procedure. The catheter <NUM> is coupled to and extends distally relative to the handle <NUM>. The catheter <NUM> is configured to be positioned in the vasculature of a subject (for example, a patient) during an atherectomy procedure to facilitate removal of occlusive material (for example, plaque) therefrom. In some embodiments and as illustrated, a distal portion <NUM> of the catheter <NUM> has a curved shape or configuration. In some embodiments, the distal portion <NUM> of the catheter <NUM> normally has a curved configuration ("normally" being understood as the catheter <NUM> not being subjected to any external contact forces due to, for example, contact with blood vessel walls) and may be deflected to other configurations. In other embodiments, the distal portion <NUM> of the catheter <NUM> normally has a straight shape or configuration and may be deflected to other configurations. In some embodiments, the catheter <NUM> is selectively rotatable about a catheter rotational axis <NUM> relative to the handle <NUM> to facilitate appropriately positioning and or "sweeping" the distal portion <NUM> of the catheter <NUM> during an atherectomy procedure. In some embodiments and as illustrated, the handle <NUM> carries a rotatable knob or dial <NUM> for selectively rotating the catheter <NUM> relative to the handle <NUM>. The catheter <NUM> includes an outer sheath <NUM>, and the outer sheath <NUM> couples to a cutter assembly <NUM> that extends distally therefrom. The cutter assembly <NUM> is described in further detail below.

<FIG> illustrate the distal portion <NUM> of the catheter <NUM>, including, among other components, the outer sheath <NUM> and the cutter assembly <NUM>. The cutter assembly <NUM> includes a ferrule <NUM> that couples to the outer sheath <NUM> and extends distally therefrom. The cutter assembly <NUM> further includes a housing <NUM> that couples to the ferrule <NUM> and extends distally therefrom. The housing <NUM> rotatably carries cutting elements. Referring specifically to <FIG>, the housing <NUM> rotatably carries a first, or distal, cutting element <NUM> and a second, or proximal, cutting element <NUM>. Rotation of the first cutting element <NUM> and the second cutting element <NUM> about a rotation axis <NUM> in a rotational direction <NUM> relative to the housing <NUM> causes the cutting elements <NUM>, <NUM> to cut occlusive material and convey the occlusive material into the housing <NUM> (a process also referred to as "debulking").

Still referring to <FIG>, the first cutting element <NUM> generally extends distally from the second cutting element <NUM> and the housing <NUM>. The first cutting element <NUM> includes a central opening <NUM> (see <FIG>) for coupling to the second cutting element <NUM>. The second cutting element <NUM> is generally disposed within the housing <NUM> and, in some embodiments and as illustrated, may be completely disposed within the housing <NUM>. The second cutting element <NUM> is also generally disposed proximally from the first cutting element <NUM>, although the second cutting element <NUM> includes a shaft or stem <NUM> that is received in the central opening <NUM>. The stem <NUM> may couple to the first cutting element <NUM> in various manners. For example, the stem <NUM> may couple to the first cutting element <NUM> via welding. In some embodiments and as illustrated, the stem <NUM> extends distally relative to the first cutting element <NUM>. The stem <NUM> includes an inner lumen <NUM> for receiving a guide wire <NUM> (shown elsewhere).

Referring specifically to <FIG>, the atherectomy device <NUM> further includes a rotatable drive shaft <NUM> that couples the first cutting element <NUM> and the second cutting element <NUM> to a prime mover (for example, a motor carried by the handle <NUM> - not shown). That is, the prime mover rotates the drive shaft <NUM>, which in turn rotates the first cutting element <NUM> and the second cutting element <NUM> to facilitate cutting occlusive material and conveying the occlusive material into the housing <NUM>. In some embodiments, the cutter assembly <NUM> captures the cut occlusive material from the blood without the use of vacuum aspiration. In other embodiments, vacuum aspiration may assist capture of the cut occlusive material. In either case, the housing <NUM> delivers the cut occlusive material to a material removal passageway <NUM> formed between the outer sheath <NUM> and the drive shaft <NUM>. The occlusive material moves proximally through the material removal passageway <NUM> due to features of the drive shaft <NUM>, as described in further detail below, and/or vacuum aspiration, and the occlusive material is thereby removed from the vasculature of the subject.

Referring to <FIG>, the first cutting element <NUM> includes one or more first, or distal, cutting flutes or blades <NUM> that extend distally relative to the housing <NUM> (shown elsewhere). In some embodiments and as illustrated, the first cutting element <NUM> includes two cutting blades <NUM>. In some embodiments and as illustrated, one or more of the first cutting blades <NUM> extend helically relative to the rotation axis <NUM>.

Referring now to <FIG>, the second cutting element <NUM> includes one or more second, or proximal, cutting flutes or blades <NUM>. In some embodiments, the second cutting element <NUM> has two times the number of blades <NUM> as the first cutting element <NUM> (shown elsewhere). In some embodiments and as illustrated, the second cutting element <NUM> includes four cutting blades <NUM>. In some embodiments and as illustrated, one or more of the second cutting blades <NUM> extend helically relative to the rotation axis <NUM>.

<FIG> illustrates a transverse sectional view the drive shaft <NUM>. The drive shaft <NUM> generally includes a distal end coupling <NUM> that couples to the cutter assembly <NUM> (shown elsewhere), a proximal end coupling <NUM> that couples to the prime mover (not shown), and a coiled section <NUM> that extends between and couples the distal end coupling <NUM> to the proximal end coupling <NUM>. The distal end coupling <NUM> is a generally cylindrical component that receives a portion of the coiled section <NUM>. The distal end coupling <NUM> may be welded to and couple to the coiled section <NUM> via a distal solder joint <NUM>. The distal end coupling <NUM> may be formed of a metal, such as stainless steel, and more specifically <NUM> stainless steel. Similarly, the proximal end coupling <NUM> is a generally cylindrical component that receives a portion of the coiled section <NUM>. The proximal end coupling <NUM> may be welded to and couple to the coiled section <NUM> via a proximal solder joint <NUM>. The proximal end coupling <NUM> may be formed of a metal, such as stainless steel, and more specifically <NUM> stainless steel.

With continued reference to <FIG>, the coiled section <NUM> includes several components that provide flexibility to the drive shaft <NUM> and inhibit penetration by occlusive material. More specifically, the coiled section <NUM> includes an inner coil <NUM> that defines, together with the distal end coupling <NUM> and the proximal end coupling <NUM>, an inner lumen <NUM> configured to receive the guide wire <NUM> (shown elsewhere). The inner coil <NUM> may have about <NUM> filars, and each filar may have a diameter of about <NUM> (<NUM> inches). The inner coil <NUM> may be right-hand wound. The inner coil <NUM> may be formed of a metal, such as stainless steel, and more specifically <NUM> stainless steel. The coiled section <NUM> also includes an intermediate coil <NUM> disposed radially outwardly from the inner coil <NUM>. The intermediate coil <NUM> may have about <NUM> filars, and each filar may have a diameter of about <NUM> (<NUM> inches). The intermediate coil <NUM> may be lefthand wound. The intermediate coil <NUM> may be formed of a metal, such as stainless steel, and more specifically <NUM> stainless steel.

The coiled section <NUM> further includes a jacket <NUM>, also referred to as an intermediate jacket and a sealing layer, disposed radially outwardly from the intermediate coil <NUM>. The jacket <NUM> may extend over the majority of the length of the coiled section <NUM>, more specifically, from the distal solder joint <NUM> to the proximal solder joint <NUM>. The jacket <NUM> provides a seal for the intermediate coil <NUM> and the inner coil <NUM> or, stated another way, the jacket <NUM> inhibits the occlusive material in the material removal passageway <NUM> (shown elsewhere) from passing through the intermediate coil <NUM>, through the inner coil <NUM>, and entering the inner lumen <NUM>. The jacket <NUM> may be formed of, for example, one or more polymers, more specifically a hydrophobic polymer, such as PTFE or fluorinate ethylene propylene (FEP). The jacket <NUM> may be formed over the intermediate coil <NUM>, for example, in a heat-shrinking process, an extrusion process, or the like.

In some embodiments, the jacket <NUM> provides one or more advantages. For example, by inhibiting occlusive material from penetrating the drive shaft <NUM>, the jacket <NUM> causes rotational friction between the drive shaft <NUM> and the guide wire <NUM> to remain relatively low and/or constant during use of the atherectomy device <NUM>. In some embodiments, an atherectomy device <NUM> including the jacket <NUM> may be subjected to rotational friction between the drive shaft <NUM> and the guide wire <NUM> during use of the atherectomy device <NUM> that is reduced by about <NUM> percent compared to a similar atherectomy device lacking the jacket <NUM>. As another example, the jacket <NUM> provides damping and reduces vibration of the drive shaft <NUM>. As yet another example, the jacket <NUM> permits the inner lumen <NUM> of the drive shaft <NUM> to be used as a delivery lumen for providing, for example, a fluid to the subject, such as a therapeutic agent, nitroglycerin, saline solution, contrast solution, or the like.

Still referring to <FIG>, the drive shaft <NUM> further includes an outer coil <NUM>, also referred to as an outer conveyor or a screw pump, disposed radially outwardly from the jacket <NUM>. The outer coil <NUM> conveys occlusive material proximally in the material removal passageway <NUM> as the drive shaft <NUM> rotates relative to the sheath. The outer coil <NUM> may have one filar, and the filar may have a diameter of about <NUM>, that is <NUM> ± <NUM> (<NUM> inches, that is <NUM> inches ± <NUM> inches). The outer coil <NUM> may have a pitch of about <NUM> (<NUM> inches). The outer coil <NUM> may be right-hand wound. The outer coil <NUM> may be formed of a metal, such as stainless steel, and more specifically <NUM> stainless steel.

Claim 1:
An atherectomy device (<NUM>) for removing occlusive material from a subject, the atherectomy device comprising:
a distal cutter assembly (<NUM>), comprising:
a housing (<NUM>);
a cutting element (<NUM>) carried by the housing and comprising at least one cutting blade (<NUM>), the cutting element being rotatable relative to the housing to cause the at least one cutting blade to cut the occlusive material and move the occlusive material into the housing;
a catheter (<NUM>) coupled to the distal cutter assembly, the catheter comprising:
a sheath (<NUM>) configured to receive the occlusive material from the housing;
a drive shaft (<NUM>) disposed within the sheath and coupled to the cutting element, the drive shaft being rotatable relative to the sheath to rotate the cutting element relative to the housing, the drive shaft comprising:
an inner coil (<NUM>) comprising an inner lumen;
an outer conveyor (<NUM>) disposed outwardly from the inner coil, the outer conveyor configured to proximally move the occlusive material in a material removal passageway (<NUM>) disposed between the drive shaft and the sheath upon rotation of the drive shaft relative to the sheath; and
a sealing layer (<NUM>) disposed between the inner coil and the outer conveyor, the sealing layer configured to inhibit the occlusive material in the material removal passageway from passing through the inner coil and entering the inner lumen.