Patent Description:
A medical catheter defining at least one lumen has been proposed for use with various medical procedures. For example, in some cases, a medical catheter may be used to access and treat defects in blood vessels, such as, but not limited to, lesions or occlusions in blood vessels.

The invention is defined by independent claim <NUM> with further embodiments disclosed in the dependent claims.

This disclosure describes example catheters including a mechanical cutting tool (or "cutter") configured to segment a thrombus, which is aspirated into an inner lumen of the catheter, into smaller pieces. The catheter may include an elongated body and an expandable member at a distal portion of the elongated body and defining at least part of a distal tip of the catheter. The expandable member is configured to expand radially outward within a hollow anatomical structure (e.g., a blood vessel) of a patient, e.g., to engage a thrombus. In some examples, the mechanical cutting tool is configured to segment the thrombus as an aspiration force pulls the thrombus proximally into an inner lumen of the elongated body. For example, the mechanical cutting tool can be introduced into the inner lumen of the elongated body and positioned within, or at least partially proximal to, the expandable member. In response to a continuous or varying aspiration force, a distal mouth of the expandable member envelops and engages a portion of the thrombus and the mechanical cutter engages and segments the thrombus into smaller pieces to facilitate efficient aspiration through the elongated body.

In some examples, the mechanical cutter includes a plurality of bristle-like extensions projecting radially outward from a support member. The extensions are configured to rotate about a rotational axis to segment (e.g., cut) the thrombus. As described herein, the mechanical cutter (or a medical system including the catheter) may include any of a number of additional features, including, but not limited to, an intermediate feature configured to modulate a radial position of the cutter within the inner lumen of the catheter, a stopper configured to modulate an axial position of the cutter within the inner lumen of the catheter, or a distal element configured to mechanically compress the thrombus into the inner lumen of the catheter for segmentation. This disclosure also describes examples of methods of forming the catheters described herein and methods of using the catheters.

<CIT> describes a neuro thrombectomy catheter with an elongate tubular body that extends between a rotatable cutter and a control. The cutter is connected to the control with a rotatable element.

<CIT> describes a catheter for removing foreign body in a blood vessel. A capturing unit provided on a distal end of a second tube can be deformed into a contracted state and an expanded state, in which the capturing unit is deployed to form a capturing chamber.

<CIT> describes a catheter for the removal of stones from the ureter, and also from the kidney or bladder. It comprises a shaft, driven if necessary, and supported and guided in an enclosing hose. At the free end of the shaft is a tool engaging with and destroying the stone, and a controllable (e.g. inflatable) expanding body is mounted on the shaft or the hose.

<CIT> describes a system of devices for treating an artery includes an arterial access sheath adapted to introduce an interventional catheter into an artery and an elongated dilator positionable within the internal lumen of the sheath body.

<CIT> describes a vascular thrombectomy catheter for removal of endoluminal thrombus.

<CIT> describes a method for capturing dislodged vegetative growth during a surgical procedure is provided. The method includes maneuvering, into a circulatory system, a first cannula having a distal end and an opposing proximal end, such that the first cannula is positioned to capture the vegetative growth en bloc. A second cannula is positioned in fluid communication with the first cannula, such that a distal end of the second cannula is situated in spaced relation to the distal end of the first cannula.

<CIT> describes a medical device and system for removing thrombi in a vessel with an elongated member, a distal expandable capturing portion and a rotating cutting unit.

Other features, objects, and advantages of the techniques described in this disclosure will be apparent from the description and drawings.

The disclosure describes a medical device, also referred to herein as a "catheter," including an expandable member configured to expand radially outward within a hollow anatomical structure (e.g., a blood vessel) of a patient, e.g., to engage with a thrombus to facilitate aspiration of the thrombus (e.g., a blood clot or other material such as a plaques or foreign bodies). The catheter also includes a mechanical cutting tool (also referred to herein as a "cutter") configured to segment at least a portion of a thrombus that is aspirated into an inner lumen of the catheter. As one non-limiting example, the mechanical cutter includes a plurality of bristle-like extensions projecting radially outward from a support member. The extensions are configured to rotate within an inner lumen of the catheter about a rotational axis to segment the thrombus.

In some examples, the mechanical cutting tool is configured to segment the thrombus as an aspiration force pulls the thrombus proximally into an inner lumen of the elongated body. For example, the mechanical cutter can be introduced into the inner lumen of the elongated body and positioned within, proximal to, or at least partially proximal to, the expandable member. In response to an aspiration force, a distal mouth of the expandable member envelops and retains a portion of the thrombus. In this configuration, the mechanical cutter can engage and segment the thrombus into smaller pieces to facilitate efficient aspiration through the elongated body.

The catheter comprises an intermediate structure.

In some examples, the catheter further comprises an intermediate structure configured to modulate a radial position of the mechanical cutter within the inner lumen of the catheter, a stopper configured to modulate a longitudinal or axial position of the cutter within the inner lumen of the catheter, and/or a distal element configured to mechanically compress the thrombus against a distal mouth of the catheter for segmentation within the inner lumen.

Example catheters in accordance with this disclosure include a relatively flexible elongated body configured to be navigated through vasculature of a patient, e.g., tortuous vasculature in a brain of the patient. The expandable member, such as an expandable stent-like structure or an expandable braid, is at a distal portion of the elongated body. In some examples, the expandable member is distinct from, but mechanically coupled to, the distal portion of the elongated body. In other examples, the expandable member is integrally formed with (e.g., laminated with and/or forming a distal extension of) the distal portion of the elongated body. The expandable member is configured to expand radially outward within a hollow anatomical structure (e.g., a blood vessel) of the patient. This may enable, for example, the expandable member to engage with a thrombus during an aspiration procedure, such as, but not limited to, a medical procedure using A Direct Aspiration first-Pass Technique (ADAPT) for acute stroke thrombectomy.

The expandable member may help improve aspiration of the thrombus into the catheter by providing a relatively large luminal diameter (and therefore exert a larger aspiration force against the thrombus or other material to be removed) and interior space for the thrombus to engage with the catheter compared to examples in which an otherwise similar catheter does not include an expandable member. For example, such a catheter that does not include an expandable member may have limited radial expansion due to a structural support member that extends to the distal end of the catheter, and may thus make it harder to aspirate a thrombus (e.g., due to a smaller cross-sectional dimension of the distal end of the catheter). The expandable member may overcome such radial expansion limitations, thereby increasing thrombus engagement, reducing the amount of time required for revascularization, and increasing revascularization success rates for various procedures, as compared to similar procedures performed using catheters that do not include an expandable member to engage a thrombus. Additionally, when implemented in concert with an applied aspiration force to proximally withdraw the thrombus into the inner lumen, the expandable member provides a clot-encapsulation region for the mechanical cutter to engage and segment the thrombus while simultaneously providing a barrier between, e.g., the mechanical cutter and the vasculature of the patient.

<FIG> is a schematic diagram illustrating an example medical aspiration system <NUM> including a suction source <NUM>, a discharge reservoir <NUM>, a fluid source <NUM>, and an aspiration catheter <NUM>. Aspiration system <NUM> may be used to treat a variety of conditions, including thrombosis. Thrombosis occurs when a thrombus (e.g., a blood clot or other material such as plaques or foreign bodies) forms and obstructs vasculature of a patient. For example, medical aspiration system <NUM> may be used to treat an ischemic insult, which may occur due to occlusion of a blood vessel (arterial or venous) that deprives brain tissue, heart tissue or other tissues of oxygen-carrying blood.

Aspiration system <NUM> is configured to remove fluid via catheter <NUM>, e.g., draw fluid from catheter <NUM> into discharge reservoir <NUM>, via a suction force applied by suction source <NUM> to catheter <NUM> (e.g., to an inner lumen of catheter <NUM>). Catheter <NUM> includes an elongated body <NUM> defining a lumen (not shown in <FIG>) terminating in a distal mouth <NUM>. To treat a patient with thrombosis, a clinician may position distal mouth <NUM> of catheter <NUM> in a blood vessel of the patient near the thrombus or other occlusion, and apply a suction force (also referred to herein as suction, vacuum force, or negative pressure) to the catheter <NUM> (e.g., to one or more lumens of the catheter) to engage the thrombus with suction force at distal mouth <NUM> of catheter <NUM>. For example, suction source <NUM> can be configured to create a negative pressure within the inner lumen of catheter <NUM> to draw a fluid, such as blood, an aspiration fluid, more solid material, or a mixture thereof, into the inner lumen via distal mouth <NUM> of catheter <NUM>. The negative pressure within the inner lumen can create a pressure differential between the inner lumen and the environment external to at least a distal portion of catheter <NUM> that causes fluid and other material to be introduced into the inner lumen via distal mouth <NUM>. For example, the fluid may flow from patient vasculature, into the inner lumen via distal mouth <NUM>, and subsequently through aspiration tubing 26A (also referred to herein as "vacuum tube 26A") into discharge reservoir <NUM>.

Once distal mouth <NUM> of aspiration catheter <NUM> has engaged the thrombus, the clinician may remove aspiration catheter <NUM> with the thrombus held within distal mouth <NUM> or attached to the distal tip of elongated body <NUM>, or suction off pieces of the thrombus (or the thrombus as a whole) until the thrombus is removed from the blood vessel of the patient through a lumen of aspiration catheter <NUM> itself and/or through the lumen of an outer catheter in which aspiration catheter <NUM> is at least partially positioned. The outer catheter can be, for example, a guide catheter configured to provide additional structural support to the aspiration catheter. The aspiration of the thrombus may be part of an aspiration procedure, such as, but not limited to, a medical procedure using ADAPT for acute stroke thrombectomy, or any other procedure for aspiration of thrombus or other material from the neurovasculature or other blood vessels.

In addition, as discussed in further detail below, aspiration of thrombus can be performed concurrently with use of a mechanical cutting tool (or "cutter") <NUM> configured to segment a portion of a thrombus that is aspirated within the inner lumen at a distal portion of catheter <NUM>.

In some examples, aspiration system <NUM> is also configured to deliver fluid from a fluid source <NUM>, for example, a fluid reservoir different from discharge reservoir <NUM>, through irrigation tubing 26B (also referred to herein as "irrigation tube 26B" or "flush tube 26B") and into the inner lumen of catheter <NUM> via a positive pressure applied by suction source <NUM>.

As used herein, "suction force" is intended to include, within its scope, related concepts such as suction pressure, vacuum force, vacuum pressure, negative pressure, fluid flow rate, and the like. A suction force can be generated by a vacuum, e.g., by creating a partial vacuum within a sealed volume fluidically connected to a catheter, or by direct displacement of liquid in a catheter or tubing via (e.g.) a peristaltic pump, or otherwise. Accordingly, suction forces or suction as specified herein can be measured, estimated, computed, etc. without need for direct sensing or measurement of force. A "higher," "greater," or "larger" (or "lower," "lesser," or "smaller") suction force described herein may refer to the absolute value of the negative pressure generated by the suction source on catheter <NUM> or another component, such as a discharge reservoir <NUM>.

In some examples, suction source <NUM> can comprise a pump (also referred to herein as "pump <NUM>" or "vacuum source <NUM>"). The suction source <NUM> can include one or more of a positive displacement pump (e.g., a peristaltic pump, a rotary pump, a reciprocating pump, or a linear pump), a direct-displacement pump (e.g., a peristaltic pump, or a lobe, vane, gear, or piston pump, or other suitable pumps of this type), a direct-acting pump (which acts directly on a liquid to be displaced or a tube containing the liquid), an indirect-acting pump (which acts indirectly on the liquid to be displaced), a centrifugal pump, and the like. An indirect-acting pump can comprise a vacuum pump, which displaces a compressible fluid (e.g., a gas such as air) from the evacuation volume (e.g., discharge reservoir <NUM>, which can comprise a canister), generating suction force on the liquid. Accordingly, the evacuation volume (when present) can be considered part of the suction source. In some examples, suction source <NUM> includes a motor-driven pump, while in other examples, suction source <NUM> can include a syringe configured to be controlled by control circuitry <NUM>, and mechanical elements such as linear actuators, stepper motors, etc. As further examples, the suction source <NUM> could comprise a water aspiration venturi or ejector jet.

Control of suction source <NUM> can comprise control, operation, and the like, of any one or combination of the component(s) making up the suction source. Accordingly, in examples in which suction source <NUM> includes a pump and an evacuation volume, control of the suction source can comprise control of only the pump, of only the evacuation volume, or of both of those components. As in examples in which suction source <NUM> includes only a pump, control of suction source <NUM> comprises control of the pump.

In some examples, suction source <NUM> is configured for bi-directional operation. For example, suction source <NUM> may be configured to create a negative pressure that draws fluid from the inner lumen of catheter <NUM> in a first flow direction and create a positive pressure that pumps fluid to catheter <NUM> and through inner the lumen in a second, opposite flow direction. As an example of this bi-directional operation, an operator of aspiration system <NUM> may operate suction source <NUM> to pump an aspiration/irrigating fluid, such as saline, from an aspiration fluid reservoir <NUM> via irrigation tube 26B to flush and/or prime catheter <NUM> (e.g., an infusion state) and subsequently draw fluid from a site of mouth <NUM> of catheter <NUM>, such as saline and/or blood, via vacuum tube 26A, into discharge reservoir <NUM>.

Aspiration system <NUM> includes control circuitry <NUM> configured to control a suction force applied by suction source <NUM> to catheter <NUM>. For example, control circuitry <NUM> can be configured to directly control an operation of suction source <NUM> to vary the suction force applied by suction source <NUM> to the inner lumen of catheter <NUM>, e.g. by controlling the motor speed, or stroke length, volume or frequency, or other operating parameters, of suction source <NUM>. For instance, control circuitry <NUM> may vary the suction force by intermittently varying the aspiration force, by periodically varying the aspiration force, or by pulsing the aspiration force, as a few non-limiting examples.

As another example, control circuitry <NUM> can be configured to control a movement of mechanical cutter <NUM>, which is configured to move according to a predetermined motion pattern to segment a portion of a thrombus that is aspirated into, and held within, a distal portion of the inner lumen of catheter <NUM>. For instance, control circuitry <NUM> may be configured to actuate a rotational motion, a longitudinal motion, or a combination thereof, of mechanical cutter <NUM> within the inner lumen of catheter <NUM>. Control circuitry <NUM> may actuate the motion of mechanical cutter <NUM> through any suitable motion mechanism, such as via a rotating cam, or via linear or rotary actuator(s) which can be electrically, electromagnetically, pneumatically or hydraulically driven to generate the desired movement of mechanical cutter <NUM>. Such linear or rotary actuator(s) can be linear solenoid(s), rotary solenoid(s), or piezoelectric driven linear or rotary actuator(s). Regardless of the type of driving mechanism or actuator, control circuitry <NUM> may cause the motion mechanism to actuate the motion of mechanical cutter <NUM> according to a predetermined speed or frequency, or to vary within a range of speeds or frequencies. As a non-limiting example, control circuitry <NUM> may cause mechanical cutter to rotate, oscillate, or otherwise periodically move at a frequency from about <NUM> Hertz (Hz) to about <NUM>,<NUM> (or equivalently for rotational motion, from about <NUM> revolutions per minute (rpm) to about <NUM>,<NUM> rpm).

Control circuitry <NUM>, as well as other processors, processing circuitry, controllers, control circuitry, and the like, described herein, may include any combination of integrated circuitry, discrete logic circuity, analog circuitry, such as one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), or field-programmable gate arrays (FPGAs). In some examples, control circuitry <NUM> may include multiple components, such as any combination of one or more microprocessors, one or more DSPs, one or more ASICs, or one or more FPGAs, as well as other discrete or integrated logic circuitry, and/or analog circuitry. In some examples, control circuitry <NUM> may further include, additionally or alternatively to electric-based processors, one or more controls that operate using fluid motion power (e.g., hydraulic power) in combination with or in addition to electricity. For example, control circuitry <NUM> can include a fluid circuit comprising a plurality of fluid passages and switches arranged and configured such that, when a fluid (e.g., a liquid or gas) flows through the passages and interacts with the switches, the fluid circuit performs the functionality of control circuitry <NUM> described herein.

Memory <NUM> may store program instructions, such as software, which may include one or more program modules, which are executable by control circuitry <NUM>. When executed by control circuitry <NUM>, such program instructions may cause control circuitry <NUM> to provide the functionality ascribed to control circuitry <NUM> herein. The program instructions may be embodied in software and/or firmware. Memory <NUM>, as well as other memories described herein, may include any volatile, non-volatile, magnetic, optical, or electrical media, such as a random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), electrically-erasable programmable ROM (EEPROM), flash memory, or any other digital media.

In the example shown in <FIG>, control circuitry <NUM> is configured to control an amount of suction force applied by suction source <NUM> to the inner lumen of catheter <NUM>. In some examples, suction source <NUM> is configured to apply a substantially continuous suction force (e.g., continuous or nearly continuous to the extent permitted by the hardware) to discharge reservoir <NUM>, and the amount of this suction force that is transferred to the inner lumen of catheter <NUM> may be adjusted by control circuitry <NUM>. As used herein, a "continuous" suction force may include a suction force having a relative strength that is generally constant over time, or that varies in strength such that distal mouth <NUM> experiences a constant pressure and/or a constant change in pressure to help pull thrombus portions into the inner lumen.

As detailed further below, a distal portion of elongated body <NUM> of catheter <NUM> includes an expandable member <NUM> configured to expand radially outward to widen distal mouth <NUM> for engaging with a thrombus. According to techniques of this disclosure, suction source <NUM>, mechanical cutter <NUM>, and expandable member <NUM> are configured to work in concert to provide improved thrombus engagement and removal. For example, while expandable member <NUM> is in an expanded configuration, suction source <NUM> may provide a continuous aspiration force within the inner lumen of expandable member <NUM>, thereby engaging and retaining a thrombus against distal mouth <NUM>. In some such examples, at least a proximal portion of the thrombus is proximally aspirated into the clot-encapsulation region provided by the inner lumen of expandable member <NUM>, wherein mechanical cutter <NUM> may then segment the thrombus into smaller pieces that may then be aspirated proximally through elongated body <NUM>.

<FIG> is a conceptual side view of an example of catheter <NUM> of system <NUM> of <FIG>, and <FIG> is a conceptual cross-sectional view of a distal portion <NUM> of the example catheter <NUM>. As shown in <FIG> and <FIG>, catheter <NUM> can include an elongated body <NUM>, a hub <NUM>, an expandable member <NUM>, and a mechanical cutting tool <NUM>. Catheter <NUM> defines an inner lumen <NUM>, including a hub lumen 40A, a body lumen 40B, and an expandable member lumen 40C.

Elongated body <NUM> is configured to be advanced through vasculature of a patient via a pushing force applied to proximal body portion 42A (e.g., via hub <NUM>) of elongated body <NUM> without buckling, kinking, or otherwise undesirably deforming (e.g., ovalization). As shown in <FIG>, elongated body <NUM> can include a plurality of concentric layers, such as an inner liner <NUM>, an outer jacket <NUM>, and a structural support member <NUM> (e.g., a coil, braid, and/or hypotube) positioned between inner liner <NUM> and outer jacket <NUM>. For example, structural support member <NUM> can be positioned between inner liner <NUM> and outer jacket <NUM> along a full length of inner liner <NUM> and/or outer jacket <NUM> or only along part of the length. Elongated body <NUM> includes a proximal body portion 42A and a distal body portion 42B, which are each longitudinal sections of elongated body <NUM>. Elongated body <NUM> extends from body proximal end 22A to body distal end 22B and defines at least one body lumen 40B (also referred to as a body inner lumen). In the example shown in <FIG>, proximal end 22A of elongated body <NUM> is received within hub <NUM> and is mechanically connected to hub <NUM> via an adhesive, welding, or another suitable technique or combination of techniques. Inner lumen <NUM> of catheter <NUM> may be defined by portions of hub <NUM>, expandable member <NUM>, and inner liner <NUM>.

Catheter <NUM> may be used as an aspiration catheter to remove a thrombus or other material such as plaques or foreign bodies from vasculature of a patient. In such examples, a suction force (e.g., a vacuum) may be applied to proximal end 20A of catheter <NUM> (e.g., via hub <NUM>) to draw a thrombus or other blockage into inner lumen <NUM>. An aspiration catheter may be used in various medical procedures, such as a medical procedure to treat an ischemic insult, which may occur due to occlusion of a blood vessel (arterial or venous) that deprives brain tissue, heart tissue or other tissues of oxygen-carrying blood.

In some examples, catheter <NUM> is configured to access relatively distal locations in a patient including, for example, the middle cerebral artery (MCA), internal carotid artery (ICA), the Circle of Willis, and tissue sites more distal than the MCA, ICA, and the Circle of Willis. The MCA, as well as other vasculature in the brain or other relatively distal tissue sites (e.g., relative to the vascular access point), may be relatively difficult to reach with a catheter, due at least in part to the tortuous pathway (e.g., comprising relatively sharp twists or turns) through the vasculature to reach these tissue sites. Elongated body <NUM> may be structurally configured to be relatively flexible, pushable, and relatively kink- and buckle- resistant, so that it may resist buckling when a pushing force is applied to a relatively proximal section of catheter <NUM> (e.g., via hub <NUM>) to advance elongated body <NUM> distally through vasculature, and so that it may resist kinking when traversing around a tight turn in the vasculature. In some examples, elongated body <NUM> is configured to substantially conform to the curvature of the vasculature. In addition, in some examples, elongated body <NUM> has a column strength and flexibility that allow at least distal body portion 42B of elongated body <NUM> to be navigated from a femoral artery, through the aorta of the patient, and into the intracranial vascular system of the patient, e.g., to reach a relatively distal treatment site.

Although primarily described as being used to reach relatively distal vasculature sites, catheter <NUM> may also be configured to be used with other target tissue sites. For example, catheter <NUM> may be used to access tissue sites throughout the coronary and peripheral vasculature, the gastrointestinal tract, the urethra, ureters, fallopian tubes, veins and other hollow anatomical structures of a patient.

Expandable member <NUM> is configured to radially expand within a vessel of a patient, e.g., to expand a distal mouth <NUM> of catheter <NUM> to enable catheter <NUM> to better engage a thrombus within the vessel. Expandable member <NUM> enables catheter <NUM> to exhibit the improved navigability characteristics of a catheter body with a relatively small diameter while still providing catheter <NUM> with the improved engagement and suction characteristics that may be attributed to having a large-diameter distal end 20B.

Expandable member <NUM> is positioned at distal body portion 42B of elongated body <NUM>, such that a distal end 36B of expandable member <NUM> also defines distal end 20B of catheter <NUM> and distal mouth <NUM> open to inner lumen <NUM> of catheter <NUM>. For example, expandable member lumen 40C (also referred to herein as an "expandable member inner lumen") may form a distal extension or distal portion of the body inner lumen 40B of elongated body <NUM>. In these examples, expandable member lumen 40C is in fluid communication with inner lumen 40B of the elongated body <NUM>.

In some examples, in its expanded states, expandable member <NUM> defines a tubular, cylindrical, or funnel shape configured to provide catheter <NUM> with a relatively large diameter (or other maximum cross-sectional diameter) distal end 20B (compared to, for example, proximal body portion 42A of elongated body <NUM>) and interior space 40C for better encapsulation of, and engagement, with a thrombus (e.g., clot or embolus).

Expandable member <NUM> can include a frame configured to expand radially outward, thereby expanding lumen 40C radially outward. For example, the expandable frame can enable expandable member <NUM> to maintain its expanded shape (after it is expanded), even in the presence of a suction force applied to inner lumen <NUM> of catheter <NUM> during an aspiration process. Example expandable frames include an expandable-stent-like structure or an expandable tubular braid, weave, or mesh.

In any of these examples, expandable member <NUM> may include a flexible membrane <NUM> coupled to (e.g., radially inward and/or radially outward of) the expandable frame, or integrated into the expandable frame. In some examples, flexible membrane <NUM> may be formed of an elastomeric material, such as polyolefin thermoplastic elastomers, polyurethane elastomeric alloys or silicone, that permits the expansion of expandable member <NUM>. In other examples, expandable member <NUM> does not include such flexible membrane <NUM>.

Expandable member <NUM> can be configured to facilitate thrombus removal. In examples in which catheter <NUM> is used with an aspiration procedure, the size and shape of expandable member <NUM> may enable catheter <NUM> to better engage a thrombus by increasing the distal opening <NUM> into which the thrombus may be received, increasing the total aspiration force exerted on the thrombus via a larger luminal area, and/or by distributing the aspiration forces over a greater portion of the thrombus rather than a localized area, thereby allowing the thrombus to be aspirated into catheter <NUM> more effectively. Expandable member <NUM> enables catheter <NUM> to maintain a relatively small-diameter elongated body <NUM> (e.g., within proximal body portion 42A) to facilitate navigability of catheter <NUM>, while also enabling catheter <NUM> to exhibit improved engagement and suction force characteristics that may be attributed to having a large-diameter distal end 20B. In some examples, the presence of expandable member <NUM> may lead to improved revascularization success rates, such as due to the improved thrombus engagement and/or suction (e.g., to better pull the entirety of the thrombus into catheter <NUM> during aspiration) as described herein.

Expandable member <NUM> may be of any suitable length and diameter, which may be selected based on the target vessel or particular procedure being performed. For example, expandable member <NUM> may be made be long enough to fully engulf a thrombus (e.g., an average amount of thrombus material), but short enough to avoid excessive friction between an outer surface of expandable member <NUM> and an inner surface of an introducer sheath or an outer catheter. In some examples, expandable member <NUM> may be about <NUM> centimeters to about <NUM> centimeters long, measured in a direction parallel to longitudinal axis <NUM>. For example, expandable member <NUM> may be about <NUM>, about <NUM>, or about <NUM> in length, such as from about <NUM> to about <NUM>.

In some examples, distal end 20B of catheter <NUM> (or equivalently, distal end 36B of expandable member <NUM>) may be about <NUM> percent to about <NUM> percent of the diameter of the proximal end 36A of expandable member <NUM>. In some examples, the expanded outer diameter or the cross-sectional dimension of expandable member <NUM> at distal end 36B may be about <NUM> percent to about <NUM> percent of the diameter of elongated body <NUM> in a region proximal to expandable member <NUM>. In other examples, expandable member <NUM> may expand to about <NUM> percent, <NUM> percent, <NUM> percent, or another larger percentage of the outer diameter or cross-sectional dimension of a more-proximal portion of elongated body <NUM>.

Expandable member <NUM> is configured to expand from a collapsed configuration (also referred to herein as a "contracted," "compressed," or "delivery" configuration) to an expanded configuration (also referred to herein as a "deployed" configuration) using any suitable technique. In some examples, expandable member <NUM> may be balloon-expandable. For example, once elongated body <NUM> is positioned within the vessel of a patient adjacent a target treatment site, a balloon (not shown) may be introduced through lumen <NUM> of catheter <NUM> and inflated to radially expand expandable member <NUM> from a collapsed configuration to an expanded configuration.

In other examples, expandable member <NUM> may be configured to self-expand. For example, the expandable frame of expandable member <NUM> may be formed from a metal, and may include a shape-memory material such as Nitinol (and, optionally, additional material(s) or metal(s) such as radiopaque material(s) or metal(s)). In some such examples as described further below, an outer sheath can be positioned over expandable member <NUM> to retain expandable member <NUM> in a collapsed configuration, e.g., during navigation of elongated body <NUM> to a target treatment site within the vasculature of a patient. Once at the target treatment site, the outer sheath can be retracted or elongated body <NUM> may be extended distally outward from the sheath to allow expandable member <NUM> to self-expand. In other examples, catheter <NUM> may be navigated through vasculature with expandable member <NUM> already in an expanded state.

In other examples, an electrical energy may be used to expand expandable member <NUM>. For example, expandable member <NUM> (or a portion or a layer thereof) may be formed from a material or metal that bends or deflects in response to a current passed therethrough (or to heat generated as a result of such current). One such type of material is shape memory alloy actuator material, e.g. Nitinol or Flexinol™ available from Dynalloy, Inc. of Irvine, California USA.

Hub <NUM> may be positioned at (e.g., proximal to or at least partially overlapping with) a proximal body portion 42A of elongated body <NUM>. Proximal end 34A of hub <NUM> may define catheter proximal end 20A of catheter <NUM> and may include a proximal opening <NUM> aligned with inner lumen 40B of elongated body <NUM>, such that inner lumen 40B of elongated body <NUM> may be accessed via proximal opening <NUM> and, in some examples, closed via proximal opening <NUM>. For example, hub <NUM> may include a luer connector, a hemostasis valve, or another mechanism or combination of mechanisms for connecting hub <NUM> to another device such as vacuum source <NUM> (<FIG>) for performing the aspiration techniques described herein. In some examples, proximal end 20A of catheter <NUM> can include another structure in addition to, or instead of, hub <NUM>.

In some examples, inner liner <NUM> of elongated body <NUM> defines at least a portion 40B of inner lumen <NUM> of catheter <NUM>, inner lumen 40B defining a passageway through elongated body <NUM>. In some examples, inner lumen 40B may extend over the entire length of inner liner <NUM> (e.g., from proximal end 22A of elongated body <NUM> to distal end 22B). Inner lumen 40B may be sized to receive a medical device (e.g., another catheter, a guidewire, an embolic protection device, a stent, a mechanical cutting tool, or any combination thereof), a therapeutic agent, or the like. Elongated body <NUM>, alone or with inner liner <NUM> and/or other structures, may define a single inner lumen <NUM>, or multiple inner lumens (e.g., two inner lumens or three inner lumens) of catheter <NUM>.

Inner lumen 40B formed at least by inner liner <NUM> may define an inner diameter of elongated body <NUM>. The diameter of inner lumen 40B (as measured in a direction perpendicular to a longitudinal axis <NUM> of elongated body <NUM>) may vary based on the one or more medical procedures with which catheter <NUM> may be used. In some examples, the diameter of inner lumen 40B of elongated body <NUM> may be substantially constant (e.g., constant or nearly constant) from proximal end 22A to distal end 22B or may taper (gradually or more step-wise) from a first inner diameter at proximal end 22A to a second, smaller inner diameter just proximal to expandable member <NUM>. As described further below, the inner diameter of expandable member <NUM> may be larger than the inner diameter of elongated body <NUM> proximal to expandable member <NUM> while expandable member <NUM> is in an expanded configuration.

Inner liner <NUM> may be formed using any suitable material, such as, but not limited to, polytetrafluoroethylene (PTFE), expanded PTFE (ePTFE, e.g., unidirectional ePTFE or bi-directional ePTFE), a fluoropolymer, perfluoroalkyoxy alkane (PFA), fluorinated ethylene propylene (FEP), polyolefin elastomers, Low Density Polyethylene (LDPE) (e.g., about 42D), a PTFE having a durometer of about 60D, High Density Polyethylene (HDPE), or any combination thereof.

In some examples, one or more portions of the inner surface of inner liner <NUM> defining inner lumen 40B (and in some examples, the inner surface of expandable member <NUM> defining inner lumen 40C) may be lubricious to facilitate the introduction and passage of a medical device (e.g., another catheter, a guide member, an embolic protection device, a stent, a thrombectomy device, or any combination thereof), a therapeutic agent, a thrombus, or the like, through lumen 40B. A lubricious inner liner <NUM> may also enable relatively easy tracking of elongated body <NUM> over a guide member (e.g., a guidewire or a microcatheter). In some examples, the material from which portions of inner liner <NUM> is formed may itself be lubricious (e.g., PTFE). In addition to, or instead of, being formed from a lubricious material, in some examples, an inner surface of inner liner <NUM> is coated with a lubricious coating, such as a hydrophilic coating.

Elongated body <NUM> includes one or more structural support members <NUM> positioned over inner liner <NUM>. Structural support member <NUM> is configured to increase the structural integrity of elongated body <NUM> while allowing elongated body <NUM> to remain relatively flexible. For example, structural support member <NUM> may be configured to help elongated body <NUM> substantially maintain its cross-sectional shape (e.g., circular or nearly circular) or at least help prevent elongated body <NUM> from buckling or kinking as it is navigated through tortuous anatomy. Additionally, or alternatively, structural support member <NUM>, together with inner liner <NUM>, and outer jacket <NUM>, may help distribute both pushing and rotational forces along a length of elongated body <NUM>, which may help prevent kinking of elongated body <NUM> upon rotation of body <NUM> or help prevent buckling of body <NUM> upon application of a pushing force to body <NUM>. As a result, a clinician may apply pushing forces, rotational forces, or both, to the proximal portion of elongated body <NUM>, and such forces may cause a distal portion of elongated body <NUM> to advance distally, rotate, or both, respectively.

Structural support member <NUM> may include one or more tubular braided structures, one or more coil members defining a plurality of turns, e.g., in the shape of a helix, one or more hypotubes, or a combination of one or more braided structures, one or more coil members, and/or one or more hypotubes. Thus, although the examples of the disclosure primarily describe structural support member <NUM> as a coil, in other examples, catheter <NUM> may include a braided structure instead of a coil, a braided structure in addition to a coil, or a combination that includes one or more of each structure. As one example, a proximal portion of structural support member <NUM> may include a braided structure and a distal portion of structural support member <NUM> may include a coil member.

Structural support member <NUM> can be made from any suitable material, such as, but not limited to, a metal (e.g., a nickel titanium alloy (Nitinol), stainless steel, tungsten, titanium, gold, platinum, palladium, tantalum, silver, or a nickel-chromium alloy, a cobalt-chromium alloy, or the like), a polymer, a fiber, or any combination thereof. In some examples, structural support member <NUM> may include one or more metal wires braided or coiled around inner liner <NUM>. The metal wires may include round wires, flat-round wires, flat wires, or any combination thereof.

Structural support member <NUM> is positioned proximal to expandable member <NUM>. In some examples, structural support member <NUM> and expandable member <NUM> are integrally formed. In other examples, expandable member <NUM> is mechanically coupled to structural support member <NUM> and/or layered between (at least in a proximal portion of the expandable member <NUM>) inner liner <NUM> and outer jacket <NUM>. For example, expandable member <NUM> and structural support member <NUM> can be formed independently of one another, and the proximal end of expandable member <NUM> may be coupled to the distal end of structural support member <NUM>. In some examples, expandable member <NUM> and structural support member <NUM> may be joined via welding, brazing, soldering, adhesives, epoxy, mechanical connections (e.g., hooks), or other suitable technique.

In other examples, expandable member <NUM> may not be coupled to structural support member <NUM> or may not be in direct contact (e.g., abutting contact) with structural support member <NUM>, although the two members may be in the same radial layer of elongated body <NUM> (and/or have the same inner diameter and/or outer diameter where structural support member <NUM> and expandable member <NUM> meet or come closest to each other in the longitudinal direction). For example, the distal end of structural support member <NUM> may be adjacent to the proximal end of expandable member <NUM> but separated by a small gap. In such examples, structural support member <NUM> and expandable member <NUM> may be in the same radial layer and inner liner <NUM>, outer jacket <NUM>, or both may secure both expandable member <NUM> and structural support member <NUM> in place along elongated body <NUM>.

In some examples, structural support member <NUM> may be coupled, adhered, or mechanically connected to at least a portion of an outer surface of inner liner <NUM>. For example, structural support member <NUM> may be positioned over inner liner <NUM> and secured in place (e.g., fixed) relative to inner liner <NUM> by outer jacket <NUM> using a melt-reflow/heat shrink process, via adhesives or other suitable technique. Additionally or alternatively, structural support member <NUM> may be secured to inner liner <NUM> with the assistance of a support layer (not shown) that helps adhere structural support member <NUM> to one or both of inner liner <NUM> and outer jacket <NUM>. The support layer may include a thermoplastic material or a thermoset material, such as a thermoset polymer or a thermoset adhesive that bonds to inner liner <NUM>, outer jacket <NUM>, or both.

One or both of inner liner <NUM> or outer jacket <NUM> may extend over the entire length of expandable member <NUM> or may extend over only a portion of the length of expandable member <NUM>. For example, flexible membrane <NUM> may include a distal portion of inner liner <NUM> extending over only part of the length of expandable member <NUM> leaving portions of expandable member <NUM> exposed to inner lumen 40C. The exposed portions of expandable member <NUM> may provide better engagement with a thrombus and/or prevent distal migration of thrombus from catheter <NUM> due to the texture of expandable member <NUM> or direct electrostatic engagement with expandable member <NUM>.

In the example shown in <FIG>, outer jacket <NUM> is positioned over structural support member <NUM> and inner liner <NUM>, the structural support member <NUM> being positioned between portions of inner liner <NUM> and outer jacket <NUM>. In some examples, outer jacket <NUM> may be positioned around structural support member <NUM> such that outer jacket <NUM> covers at least a part or all of both inner liner <NUM> and structural support member <NUM>. Outer jacket <NUM>, together with inner liner <NUM> and structural support member <NUM>, may be configured to define elongated body <NUM> having the desired structural characteristics (e.g., flexibility, kink resistance, torque responsiveness, structural integrity, pushability, and column strength, which may be a measure of a maximum compressive load that can be applied to elongated body <NUM> without taking a permanent set). For example, outer jacket <NUM> may have stiffness characteristics that contribute to the desired stiffness profile of elongated body <NUM>.

In some examples, outer jacket <NUM> may be formed to have a stiffness that decreases from a proximal end 22A of elongated body <NUM> toward distal end 22B. The lowered stiffness of outer jacket <NUM> within the distal body portion 42B of elongated body <NUM> may improve the flexibility and navigability of catheter <NUM> through tortious vasculature of the patient, while the relatively higher stiffness of outer jacket <NUM> within the proximal body portion 42A of catheter <NUM> may provide better pushability or kink resistance. In some examples, outer jacket <NUM> may be formed from two or more different materials with different mechanical properties that enable outer jacket <NUM> to exhibit the desired stiffness characteristics. In some examples outer jacket <NUM> may define a stiffness that is greater than the stiffness of flexible membrane <NUM> of expandable member <NUM>.

In some examples, outer jacket <NUM> may be formed using any suitable material including, but are not limited to, polymers, such as a polyether block amide (e.g., PEBAX®, commercially available from Arkema Group of Colombes, France), an aliphatic polyamide (e.g., Grilamid®, commercially available from EMS-Chemie of Sumter, South Carolina), another thermoplastic elastomer (e.g., a thermoplastic, elastomeric polymer configured to accommodate radial expansion of expandable member <NUM>), polyurethanes, polyamides, or other thermoplastic material, or combinations thereof.

Outer jacket <NUM> may be heat-shrunk around structural support member <NUM> and, in some examples, at least a portion (e.g., a proximal portion) of expandable member <NUM> to secure the two members <NUM>, <NUM> in the same radial layer. In some examples, during the heat shrinking of outer jacket <NUM> around structural support member <NUM>, the material of outer jacket <NUM> may flow into at least some of the inner spacings or gaps (e.g., gaps between the adjacent turns of the coils, or between the struts or braids) within structural support member <NUM> or expandable member <NUM> such that portions of outer jacket <NUM>, structural support member <NUM>, and/or expandable member <NUM> form a laminated structure.

In some examples, at least a portion of an outer surface of outer jacket <NUM> and/or expandable member <NUM> includes one or more coatings, such as, but not limited to, an anti-thrombogenic coating, which may help reduce the formation of thrombi in vitro, an anti-microbial coating, and/or a lubricating coating.

Although a coating or another material may be applied over the outer surface of outer jacket <NUM>, outer jacket <NUM> may still substantially define a shape and size of the outer surface of elongated body <NUM>. In some examples, the outer diameter of elongated body <NUM> may be substantially constant (e.g., constant or nearly constant) along the length of elongated body <NUM>. In other examples, the outer diameter of elongated body <NUM> may taper from the first outer diameter within proximal body portion 42A of elongated body <NUM> to a second outer diameter at a point proximate to the proximal end 36A of expandable member <NUM>.

In some examples, both inner liner <NUM> and outer jacket <NUM> terminate proximal to a distal end of expandable member <NUM>. In other examples, inner liner <NUM> and outer jacket <NUM> can have other arrangements relative to expandable member <NUM>.

Catheter <NUM> includes a mechanical cutting tool, or "cutter," <NUM>, configured to be disposed (e.g., introduced and positioned) within inner lumen <NUM> of catheter <NUM> and remain within inner lumen <NUM> during an aspiration procedure. Mechanical cutter <NUM> is configured to move to segment portions of a thrombus that contact mechanical cutter <NUM>, e.g., thrombus portions that become aspirated into inner lumen <NUM> through distal mouth <NUM>. As one non-limiting example, mechanical cutter <NUM> may be configured to rotate about central longitudinal axis <NUM> of catheter <NUM> or another rotational axis in order to cut the thrombus portions into smaller portions. In other examples, mechanical cutter <NUM> may additionally or alternatively be configured to oscillate proximally and distally in order to segment the thrombus into smaller portions. In other examples, mechanical cutter <NUM> may be configured to move according to other motion patterns, or any combination thereof.

<FIG> and <FIG> depict a first example configuration of mechanical cutter <NUM>. In the example depicted in <FIG> and <FIG>, mechanical cutter <NUM> includes a brush-type configuration including an elongated support structure <NUM> and a plurality of brush-like bristles <NUM> extending radially outward from support structure <NUM>. However, this example configuration is not intended to be limiting. Mechanical cutter <NUM> can have any suitable configuration for engaging and segmenting a thrombus within a patient's vasculature. For instance, in other examples, mechanical cutter <NUM> may include a corkscrew-type or auger-type radial extension that wraps helically around an outer circumference of support structure <NUM>.

In some examples, any or all of bristles <NUM> (or other similar elongated extensions of mechanical cutter <NUM>) are configured to extend outward from support structure <NUM> at an angle other than perpendicular to central longitudinal axis <NUM> when support structure <NUM> is substantially longitudinally aligned (e.g., longitudinally aligned or within <NUM>-<NUM> degrees or less) with central longitudinal axis <NUM>.

Each of bristles <NUM> may define an individual bristle length (e.g., as measured from an end connected to support structure <NUM> to a free end, e.g., in a radial direction in some examples described herein) such that the outer-most ends of bristles <NUM> (e.g., the free ends of bristles <NUM> that are not rigidly coupled to support structure <NUM>) collectively define a geometric shape of mechanical cutter <NUM>. In the example depicted in <FIG>, <FIG>, <FIG>, and <FIG>, the outer-most ends of bristles <NUM> define a generally conical shape or evergreen-tree shape, having a generally circular outer circumference (along a planar cross-section taken orthogonal to central longitudinal axis <NUM>) that tapers in a distal direction. In other examples, such as the example depicted in <FIG>, the outer-most ends of bristles <NUM> define a generally conical shape or evergreen-tree shape that tapers in a proximal direction (e.g., that widens in circumference along a distal direction). In other examples, bristles <NUM> can collectively define virtually any two-dimensional or three-dimensional geometric shape. As another example, bristles <NUM> may taper in a distal direction according to a non-linear pattern so as to collectively define a hemispherical shape or dome-shape (e.g., an open umbrella shape).

In some examples, bristles <NUM> are relatively rigid, forming a blender-type mechanism when mechanical cutter <NUM> is actuated. In other examples, bristles <NUM> may be flexible (e.g., non-self-supporting wires, fibers, or the like), forming a weed-wacker-type mechanism to segment the thrombus when mechanical cutter <NUM> is actuated.

In some examples herein, similar to expandable member <NUM>, mechanical cutter <NUM> may be configured to transition between a collapsed, contracted, or delivery configuration (depicted in <FIG>), and an expanded or deployed configuration (depicted in <FIG> and <FIG>). For example, as depicted in <FIG>, in examples in which mechanical cutter <NUM> includes a plurality of elongated bristles <NUM>, bristles <NUM> may be configured to hingedly revolve or collapse radially inward toward support structure <NUM> in order to reduce a maximum outer dimension, e.g., diameter "D," of mechanical cutter <NUM> for delivery of mechanical cutter <NUM> distally through inner lumen <NUM> of catheter <NUM>. Once mechanical cutter <NUM> is positioned at a desired location within inner lumen <NUM>, mechanical cutter <NUM> may be expanded to the deployed configuration, depicted in <FIG> and <FIG>, through any suitable means, such as means similar to those described above with respect to expandable member <NUM>. As one non-limiting example, mechanical cutter <NUM> may include a pull wire (not shown) configured to re-orient bristles <NUM> relative to support structure <NUM>. While in the deployed configuration, mechanical cutter <NUM> is then radially inwardly compressible back to the delivery configuration, either via the same mechanism (e.g., a pull wire) or another mechanism.

As another example, bristles <NUM> and/or support structure <NUM> may be (e.g., integrally) formed from a shape-memory material, such as Nitinol, into a shape in which bristles <NUM> are inclined to extend radially outward into the expanded configuration shown, e.g., in <FIG>, <FIG>, <FIG>. In some such examples, bristles <NUM> may fold down into the compressed or delivery configuration when introduced into lumen 40A, e.g., in response to contact with the interior surface of elongated body <NUM> or another structure, as detailed further below. Bristles <NUM> may then self-expand radially outward into the expanded configuration of mechanical cutter <NUM> when sufficient space is available, for instance, when advanced into a wider portion of inner lumen 40B, 40C, etc..

Mechanical cutter <NUM> is configured to be used in conjunction with an aspiration force, as described above. For instance, as detailed below with respect to <FIG>, a medical system may include aspiration source <NUM> of <FIG> (e.g., a vacuum) configured to at least partially proximally withdraw a thrombus through a distal mouth <NUM> of catheter <NUM> and into lumen 40C of expandable member <NUM> and/or lumen 40B of elongated body <NUM>. While held within lumen(s) 40B, 40C by the aspiration force, mechanical cutter <NUM> is configured to engage with and segment the thrombus, e.g., to remove a thrombus portion from the remainder of the thrombus body located external and distal to lumen(s) 40B, 40C.

In some examples, catheter <NUM> includes additional structural elements configured to modulate or otherwise control a relative position and/or orientation of mechanical cutter <NUM> within inner lumen <NUM> of catheter <NUM>. Structural elements may include, for example, an intermediate structure configured to modulate a radial position of mechanical cutter <NUM> within inner lumen <NUM>, and a stopper element configured to modulate an axial or longitudinal position of mechanical cutter <NUM> within inner lumen <NUM>. For instance, <FIG> is a conceptual cross-sectional view of another example of the distal portion <NUM> of catheter <NUM> of <FIG> showing mechanical cutting tool <NUM> in a deployed configuration, where the cross-section is taken through a center of the catheter and along longitudinal axis <NUM>. In the example depicted in <FIG>, catheter <NUM> includes an intermediate structure <NUM> positioned radially outward (relative to central longitudinal axis <NUM>) from at least a portion of cutting tool <NUM> (e.g., just a proximal portion or an entire length of cutting tool <NUM>), and positioned radially inward from at least a portion of interior surface <NUM> of elongated body <NUM>. Interior surface <NUM> can be, for example, an interior surface of inner liner <NUM> defining body lumen 40B.

In an embodiment of the invention depicted in <FIG>, intermediate structure <NUM> is an elongated hollow sheath radially surrounding mechanical cutter <NUM>. In other examples, intermediate structure <NUM> may have any suitable physical configuration configured to perform the functions described below. In embodiments in which intermediate structure <NUM> comprises an elongated sheath, an exterior surface of the sheath may be sized or otherwise configured to substantially conform to interior surface <NUM> of elongated body <NUM>, thereby reducing or eliminating a gap between the surfaces that could otherwise receive and retain undesired portions of segmented thrombus material. This may enable, for example, all or most of the thrombus to move (under an aspiration force) proximally through an inner lumen of intermediate structure <NUM>, rather than through a radial space between an outer surface of intermediate structure <NUM> and interior surface <NUM> of elongated body <NUM>.

As one example function of intermediate structure <NUM>, intermediate structure <NUM> may be configured to radially surround all or part of mechanical cutter <NUM>, such as one or more (or all) of the segmenting bristles <NUM> of mechanical cutter <NUM>, in order to prevent bristles <NUM> or other similar structure of mechanical cutter <NUM> from contacting the interior surface <NUM> of elongated body <NUM> while mechanical cutter <NUM> is actuated, e.g., is in motion. In other words, intermediate structure <NUM> is configured to reinforce and protect elongated body <NUM> from abrasive forces conveyed by mechanical cutter <NUM>. In some such examples, intermediate structure <NUM> may be made from a material that is substantially scratch-resistant or otherwise durable, e.g., more durable than an inner surface of elongated body <NUM>.

As another example function, intermediate structure <NUM> may be configured to radially fix or center mechanical cutter <NUM> at a desired radial position (relative to central longitudinal axis <NUM>) within inner lumen 40B of elongated body <NUM>. For example, as shown in <FIG>, intermediate structure <NUM> may be rigidly coupled to mechanical cutter <NUM> via a centering mechanism, such as centering extensions <NUM>, in order to suspend and approximately center cutting tool <NUM> within inner lumen <NUM> of elongated body <NUM>. In example catheters without a similar centering structure <NUM>, mechanical cutter <NUM> would be capable of moving radially relative to interior surface <NUM> of elongated body <NUM> (or the inner surface of intermediate structure <NUM>, if present), thereby applying mutual friction between mechanical cutter <NUM> and the respective inner surface, and retarding a movement, such as a rotational motion, of mechanical cutter <NUM>, and reducing the thrombus-segmentation efficacy of mechanical cutter <NUM>.

Centering structure <NUM> may be positioned at any suitable axial position along an axial length of support structure <NUM>. As shown in <FIG>, centering structure <NUM> may be positioned at a relatively proximal position within inner lumen <NUM>. In other examples, centering structure may be located at a more distal position within inner lumen <NUM>, e.g., closer to bristles <NUM>. In other examples, catheter <NUM> may include a plurality of centering structures <NUM> spaced along the axial length of support structure <NUM>. Centering structure <NUM> can have any suitable configuration, e.g., one or more relatively rigid flanges that help support structure <NUM> maintain a desired position within inner lumen <NUM>. Centering structure <NUM> is configured to enable fluid and a thrombus or segmented thrombus portions move proximally past centering structure <NUM>, e.g., to discharge reservoir <NUM> (<FIG>).

Intermediate structure <NUM> can have any suitable length measured along longitudinal axis <NUM>. In some examples, intermediate structure <NUM> extends a full length of support structure <NUM> and to a distal-most end of cutting tool <NUM>. In other examples, intermediate structure <NUM> extends only along a distal portion of cutting tool <NUM>, e.g., around some or all of bristles <NUM> in the example shown in <FIG>. Cutting tool <NUM> can be moved independently of intermediate structure <NUM> in some examples. For example, cutting tool <NUM> can be advanced through intermediate structure <NUM>. In other examples, intermediate structure <NUM> and cutting tool <NUM> are coupled together and configured to move longitudinally together through inner lumen <NUM> of catheter <NUM>.

Additionally or alternatively to an intermediate structure configured to modulate a radial position of mechanical cutter <NUM>, catheter <NUM> may include a stopper mechanism configured to modulate an axial or longitudinal position of mechanical cutter <NUM> within inner lumen <NUM>. For instance, <FIG> are conceptual cross-sectional views of three examples of the distal portion <NUM> of the catheter <NUM> of <FIG>, showing the cutting tool <NUM> in a deployed configuration, where the cross-sections are each taken through a center of the catheter <NUM> and along a longitudinal axis <NUM>. Each of <FIG> further illustrates an example of a stopper mechanism 78A-78C (also referred to in general herein as "stopper <NUM>") configured to modulate an axial position of mechanical cutter <NUM> relative to the inner lumen <NUM> of elongated body <NUM>. While mechanical cutter <NUM> may generally be configured to move proximally and distally within inner lumen <NUM> of elongated body <NUM>, each stopper <NUM> is configured to prevent mechanical cutter <NUM> from extending distally past a predetermined point. For example, stopper <NUM> may be configured to prevent cutting tool <NUM> from extending distally into inner lumen 40C of expandable member <NUM>. In other examples, stopper <NUM> may be configured to enable mechanical cutter <NUM> to extend distally into inner lumen 40C of expandable member <NUM>, but further configured to prevent mechanical cutter <NUM> from extending distally outward from distal mouth <NUM> of expandable member <NUM>. Although described and depicted herein as distinct structures, it is to be understood that any of stoppers <NUM> may be coupled to, may be integrated with, or may be the same structure as intermediate structure <NUM> and/or centering structure <NUM> (<FIG>).

<FIG> is a conceptual cross-sectional view of another embodiment of the distal portion <NUM> of catheter <NUM> of <FIG> showing a mechanical cutting tool <NUM> in a deployed configuration, where the cross-section is taken through a center of the catheter and along longitudinal axis <NUM>. Cutting tool <NUM> may be an example of cutting tool <NUM> of <FIG>, except for the differences noted herein. For instance, as depicted in <FIG>, bristles <NUM> of cutting tool <NUM> collectively define (e.g., via their radially outer-most ends) a generally conical shape or evergreen-tree shape that tapers in a proximal direction, instead of in the distal direction, as depicted in <FIG>. Different configurations and orientations of cutting tools <NUM>, <NUM>, e.g., of bristles <NUM>, may provide additional benefits with respect to aspiration of a thrombus or other occlusive material. For instance, certain configurations of bristles <NUM> may help prevent a clogging of inner lumen 40B as thrombus material is aspirated into the inner lumen. For instance, in some examples, cutting tool <NUM> may extend distally into expandable member <NUM>, thereby providing for more volume around cutting tool <NUM>. In some such examples, a tapering of bristles <NUM> along a distal direction (such that cutting tool <NUM> increases in diameter or other maximum cross-sectional dimension in a direction away from the distal end of cutting tool <NUM>) may help reduce or minimize the extent to which cutting tool <NUM> blocks aspiration force applied to distal mouth <NUM> of catheter <NUM>.

<FIG> depicts a first example stopper 78A, as described above with respect to <FIG>. Stopper 78A includes one or more radial extensions <NUM> extending radially outward from support structure <NUM>. In the example depicted in <FIG>, radial extensions <NUM> are sized to fit within inner lumen 40B of elongated body <NUM> and enable fluid and thrombus flow proximally past radial extensions <NUM>. In such examples, interior surface <NUM> of elongated body <NUM> may include a corresponding lip <NUM> extending radially inward into inner lumen 40B of elongated body <NUM>. Lip <NUM> may be sized (in a radial direction) so as to enable bristles <NUM> of mechanical cutter <NUM> to extend axially past lip <NUM>, but also sized (in a radial direction) to engage with radial extensions <NUM>. In other examples, radial extensions <NUM> may be sized so as to not fit within inner lumen 40B of elongated body <NUM>, but instead, to remain external to elongated body <NUM> and to engage with a proximal-most end 20A (<FIG>) of catheter <NUM> to prevent mechanical cutter <NUM> from extending distally past a desired point within inner lumen <NUM>.

<FIG> depicts another example stopper 78B. Stopper 78B includes one or more fluid-expandable balloons extending radially outward from support structure <NUM>. In the example depicted in <FIG>, balloons <NUM> are sized to fit within inner lumen 40B of elongated body <NUM>, and further, are variably-expandable according to an amount of fluid injected through an inner lumen of support structure <NUM>. In such examples, interior surface <NUM> of elongated body <NUM> may include a corresponding lip <NUM> extending radially inward into inner lumen 40B of elongated body <NUM>. Lip <NUM> may be sized (in a radial direction) so as to enable bristles <NUM> of mechanical cutter <NUM> to extend axially past lip <NUM> (at least while in a delivery configuration of mechanical cutter <NUM>), but also sized (in a radial direction) to engage with expandable balloons <NUM> to limit distal movement of mechanical cutter <NUM>.

In the example depicted in <FIG>, lip <NUM> may have a tapered configuration, wherein the lip extends more radially inward into inner lumen 40B along a distal direction. In such examples, the clinician may select and control an axial position at which expandable balloons <NUM> engage with lip <NUM>, by injecting an amount of fluid into balloons <NUM> to control a desired size of balloons <NUM>, corresponding to an axial position at which balloons <NUM> engage with lip <NUM>, preventing mechanical cutter <NUM> from extending distally past this axial position.

In other examples, radial extensions <NUM> may be sized so as to not fit within inner lumen 40B of elongated body <NUM>, but instead, to remain external to elongated body <NUM> and to engage with a proximal-most end 20A of catheter <NUM> to prevent mechanical cutter <NUM> from extending distally past a desired point within inner lumen <NUM>. In some examples, a portion or all of stopper <NUM> may be configured to remain external to lumen <NUM>. For instance, <FIG> depicts a third example stopper 78C. Stopper 78C includes a plug <NUM> coupled to support structure <NUM> and configured to engage with a proximal portion of catheter <NUM>, such as with proximal end 20A. Proximal end 20A in <FIG> can be, for example, another opening into inner lumen <NUM>, e.g., defined by hub <NUM>, and separate from a proximal opening that is fluidically coupled to suction source <NUM> (<FIG>).

In some examples, stopper 78C is configured to engage with proximal end 20A in order to close or cover proximal opening <NUM> to inner lumen 40A, in some instances, forming a fluid-tight seal over proximal opening <NUM>. For instance, stopper 78C may be formed from a flexible material, such as silicone, to conform to the geometry of proximal opening <NUM>, thereby forming the fluid-tight seal. In other examples, stopper 78C (or any of the stoppers <NUM> described herein) may be formed from a porous material, such as a porous mesh, enabling segmented thrombus portions or other fluids (e.g., saline, etc.) to pass therethrough.

Further illustrated in <FIG> is another example mechanism for converting mechanical cutter <NUM> between the delivery configuration (e.g., as shown in <FIG>) and the deployed configuration. As shown in <FIG>, each set of longitudinally aligned bristles <NUM> includes a corresponding runner <NUM> and set of mechanical stretchers <NUM>, collectively forming an umbrella-type mechanism for expanding bristles <NUM> radially outward, away from support structure <NUM>. Each runner <NUM> may be coupled to a pull wire (not shown) or other similar mechanism enabling a user (e.g., a clinician) to operate the umbrella-type mechanism from a position proximal to catheter <NUM>, such as external to a patient while catheter <NUM> is inserted within a vasculature of a patient.

<FIG> is a conceptual cross-sectional view of another example of the distal portion <NUM> of the catheter <NUM> of <FIG> while introduced within vasculature <NUM> of a patient with mechanical cutting tool <NUM> in a deployed configuration. <FIG> further illustrates an example distal element <NUM> of catheter <NUM>, in accordance with techniques of this disclosure. For instance, any of the above-described examples of catheter <NUM> may additionally or alternatively include a distal element <NUM> configured to apply a proximal force (indicated in <FIG> by proximal-facing arrows <NUM>) onto a distal side of thrombus <NUM> in order to bias thrombus <NUM> proximally toward and into distal mouth <NUM> of catheter <NUM>.

As shown in <FIG>, distal element <NUM> may be a component of mechanical cutter <NUM>, such as through a mechanical coupling to support structure <NUM>. In other examples, distal element <NUM> may be slidably coupled to support structure <NUM>, such that distal element is proximally and distally movable with respect to bristles <NUM> of mechanical cutter <NUM> (e.g., via a separate pull wire or other similar mechanism). In other examples, mechanical cutter may be coupled to other components of catheter <NUM>, such as elongated body <NUM>, or in other examples, may be a standalone (e.g., removably separable) element.

As used herein, distal element <NUM> may include any suitable physical structure that includes a proximal-facing surface <NUM> configured to contact and apply a proximal force <NUM> onto thrombus <NUM>. In some examples, but not all examples, distal element <NUM> may be configured to convert between a delivery configuration and a deployed configuration (e.g., the configuration shown in <FIG>), according to any suitable mechanism, such as a mechanism similar to any those described above with respect to expandable member <NUM> and mechanical cutter <NUM>.

During use, a clinician may navigate distal end 20B of catheter <NUM> toward thrombus <NUM>. Once distal end 20B is at or near a target site at a proximal side of thrombus <NUM>, the clinician may introduce mechanical cutter <NUM>, including distal element <NUM>, through inner lumen <NUM> of catheter <NUM>, while mechanical cutter <NUM> and/or distal element <NUM> are in a reduced-profile delivery configuration. The clinician may distally advance support structure <NUM> of mechanical cutter <NUM> until distal element <NUM> passes distally through or distally past thrombus <NUM> and distal element <NUM> becomes located at a position that is distal to all or part of thrombus <NUM>. The clinician may then actuate an appropriate mechanism (e.g., a pull wire, etc.) to expand distal element <NUM> from the delivery configuration to the deployed configuration depicted in <FIG>. The clinician may then apply a proximal force, such as to support structure <NUM>, to bring proximal-facing surface <NUM> into contact with a distal side of thrombus <NUM>, thereby compressing thrombus distally against distal-most end 20B of catheter <NUM> and the area surrounding distal mouth <NUM>.

As described above, the clinician may further actuate aspiration, such as a vacuum force or suction force, to further proximally withdraw at least a proximal portion <NUM> of thrombus <NUM> into distal mouth <NUM>. Distal element <NUM> and/or the aspiration force, alone or in combination, may cause proximal portion <NUM> of thrombus <NUM> to come into contact with bristles <NUM> (or an equivalent structure) of mechanical cutter <NUM>, thereby segmenting proximal portion <NUM> of thrombus <NUM>. In some examples described herein, the proximal compression from distal element <NUM> against distal mouth <NUM> may cause thrombus <NUM> to form a fluid-tight seal over distal mouth <NUM>, thereby enhancing the suction effect of the aspiration force, proximally withdrawing thrombus <NUM> farther into lumen <NUM> of catheter <NUM>.

The clinician may distally advance expandable member <NUM> and/or proximally withdraw distal element <NUM> such that a majority of thrombus <NUM> comes into contact with, and is segmented by, bristles <NUM> of mechanical cutter <NUM>. The segmented portions of thrombus <NUM> may be aspirated proximally through inner lumen <NUM> of catheter <NUM> and into a waste reservoir (not shown) via the suction force. The clinician may then proximally withdraw catheter <NUM>, including mechanical cutter <NUM>, from the vasculature of the patient.

<FIG> is a flow diagram of an example method of using catheter <NUM> of <FIG> and <FIG>. The techniques of <FIG> include inserting catheter <NUM> into vasculature of the patient (<NUM>), deploying expandable member <NUM> to expand expandable member <NUM> in the vasculature of the patient (<NUM>), distally advancing mechanical cutter <NUM> through catheter <NUM> (<NUM>), actuating mechanical cutter <NUM> (<NUM>), and aspirating a thrombus (<NUM>). In some examples, the techniques described herein include removing catheter <NUM> from the vasculature of the patient once the procedure is complete.

In some examples, inserting catheter <NUM> into vasculature of a patient (<NUM>) may include initially introducing a guidewire, guide catheter, or another guide member into the vasculature of the patient to a target treatment site. Elongated body <NUM> may then be introduced over the guidewire and advanced to the target treatment site. Additionally, or alternatively, catheter <NUM> may be introduced into vasculature of a patient with the aid of a guide catheter. For example, the guide catheter may be initially introduced into vasculature of a patient and positioned adjacent a target treatment site. Catheter <NUM> may then be introduced through an inner lumen of the guide catheter.

Once within the vasculature, expandable member <NUM> may be deployed into the vasculature (<NUM>). In some examples, expandable member <NUM> may be self-expanding and may expand without the aid of any additional expansion mechanisms once released from an outer introducer sheath. Additionally, or alternatively, expandable member <NUM> may be expanded using a balloon or pull wire. In other examples, expandable member may be expanded by applying electrical energy to expandable member <NUM>. For example, expandable member <NUM> (or a portion or layer thereof) may be constructed using a shape memory alloy actuator material.

The technique of <FIG> also includes distally advancing mechanical cutter <NUM> through inner lumen <NUM> of catheter <NUM> (<NUM>). In some examples, catheter <NUM> includes a stopper element <NUM> (<FIG>) configured to control a relative longitudinal position of mechanical cutter <NUM> within lumen <NUM> of catheter <NUM>. For instance, stopper element <NUM> may act as a distal stop that prevents a distal end or distal portion of mechanical cutter <NUM> from extending distally outward from distal mouth <NUM> of expandable member <NUM> and into direct engagement with a blood vessel wall. As another example, stopper element <NUM> may control the extent to which the distal end or distal portion of mechanical cutter <NUM> extends distally into inner lumen 40C of expandable member <NUM> from inner lumen 40B of elongated body <NUM> of catheter <NUM>. In some examples, but not all examples, the clinician may expand mechanical cutter <NUM> from a delivery configuration to a deployed configuration once mechanical cutter <NUM> is at the desired longitudinal position.

The technique of <FIG> also includes actuating mechanical cutter <NUM> (<NUM>). For instance, the clinician may actuate a user-input mechanism to initiate a rotational motion, a longitudinal motion, or both, of mechanical cutter <NUM>.

The technique of <FIG> also includes applying a suction force to inner lumen <NUM> of catheter <NUM> to proximally withdraw a thrombus into distal mouth <NUM> of catheter <NUM> (<NUM>). For example, once distal portion <NUM> of catheter <NUM> is positioned proximate to a thrombus, a clinician may actuate a suction source to apply a suction force to lumen <NUM>. The suction source can comprise a pump, such as a direct-acting pump (e.g., a peristaltic pump, or a lobe, vane, gear, or piston pump, or other suitable pumps of this type) or an indirect-acting pump (e.g., a vacuum pump, which creates a partial vacuum in an evacuation volume fluidically coupled to the liquid to be displaced). In some examples, the suction force applied to inner lumen <NUM> of catheter <NUM> is varied over time, referring to herein as cyclical aspiration. As discussed above, during this cyclical aspiration, at least a portion of the thrombus may be pulled into contact with actuated mechanical cutter <NUM>, thereby segmenting the thrombus into smaller pieces, which are then aspirated proximally through inner lumen <NUM> of catheter <NUM>. Catheter <NUM> may be removed from the vasculature once the aspiration procedure is complete.

Claim 1:
A medical device comprising:
an elongated body (<NUM>) comprising an expandable member (<NUM>) disposed at a distal portion of the elongated body, the expandable member defines an expandable distal mouth (<NUM>) of the catheter, and the elongated body further comprising an interior surface (<NUM>) defining an inner lumen (<NUM>);
a rotatable cutting tool (<NUM>) located within the inner lumen of the elongated body, the rotatable cutting tool configured to segment a thrombus into smaller pieces while an aspiration force pulls the thrombus proximally into the inner lumen; and characterised in that the medical device further comprises an intermediate structure (<NUM>) oriented radially between the rotatable cutting tool and the interior surface of the elongated body, the intermediate structure configured to prevent the cutting tool from contacting the interior surface of the elongated body, wherein the intermediate structure comprises a sheath that radially surrounds the cutting tool.