Patent Description:
The present disclosure relates to catheters and, more particularly, relates to an aspiration catheter augmented by hydrodynamic vortices that are generated by very high-speed rotation of a flexible non-shaped shaft.

Thrombosis is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. The formation of a thrombus can occur within the heart or any artery or vein in the body, leading to a myriad of medical problems such as myocardial infarction, stroke, pulmonary embolism, and deep venous thrombosis. Rapid thrombectomy is frequently needed in cases of <NUM>) obstruction of arteries of delicate organs, such as the heart or the brain; <NUM>) large clots interrupting blood flow in major vessels or causing severe symptoms; or <NUM>) when systemic delivery of the drugs is too risky.

Multiple thrombectomy devices have emerged in the last decades. However, these devices continue to be largely ineffective with large clot burden, "organized" (i.e. thick) clots, and clots extending from large to small vessels, and many such devices cause distal embolization of clots and vascular damage as they dispose the cutting or macerating mechanism directly into the vascular lumen. In addition, devices are generally specific for a certain lumen size, which translates to the need of combining multiple sizes and types of devices in the same procedure. Mechanical thrombectomy in stroke presents additional challenges based on the tortuosity of vessel and the delicate nature of vessel walls. In this regard, mechanical thrombectomy mechanisms that have been successfully used in the peripheral vasculature to remove clots, some of which are described below, are too bulky and stiff for navigating the complex cerebral artery geometries, release too many clot particles downstream leading to microvascular occlusion, or are too abrasive for delicate brain arterial walls.

Modification of catheter shape has been suggested or disclosed in the prior art to enhance aspiration of intravascular clots. In <CIT>, a suction cannula is described with a distal end that is deployable to expand from a first diameter to a relatively larger second diameter with a funnel shape. The differential diameter is believed to induce a laminar flow circumferentially along the interior surface of the funnel to generate a vortex flow into the distal end of suction cannula. In the presence of a vortex flow, such a flow can act to direct the undesirable material toward the distal end to allow the material to subsequently be pulled into the distal end by suctioning.

Other systems and methods have been disclosed in the prior art to achieve thrombectomy based on waterjet thrombectomy catheters. The catheters described may have proximal-to-distal waterjet flow, such as <CIT>, or distal-to-proximal-directed waterjet flow past a window, orifice or gap at the distal end of the catheter, re-entering the catheter and pushing flow through an evacuation lumen, such as in <CIT> The Bonnette Patent describes a dual catheter assembly with the inner tube having a high pressure lumen with a distally located jet emanator having one or more rearwardly directed orifices for directing one or more jets of saline toward the distal end of a flow director which fragments and drags clots into the outer larger catheter.

Catheter-based instruments with different macerating mechanisms have been suggested or disclosed in the prior art for to fragment clots for thrombectomy in the vascular lumen with revascularization of arteries and veins. With these devices, the clot is broken into smaller pieces, most of which migrate further downstream, decreasing the central obstruction. <CIT>discloses a catheter for clearing a vessel composed by a rotary drive mechanism that rotates a helical shaped cutting tool. As the rotor rotates, dual cutting slots engage and sever the material along the vessel wall. <CIT>discloses another catheter device for removing material having a rotatable screw thread distal end adjacent a shearing member also near the distal end. By application of the "Archimedes" screw action, in combination with vacuum, thrombus is drawn into the device in order to be macerated by shear and removed. <CIT>describes a helically wound coil wire delivered through a catheter with or without vacuum that is disposed outside the catheter within the clot mass in the arterial lumen and rotated at preferable speed of <NUM> to 6000rpm to cause fibrin to be wound around the shaft. As the fibrin fibers follow the rotating core, they are eventually stripped away from the clot, which loses its structural network. This leads to release of red blood cells back into the circulatory system, since the insoluble material is retained on the core wire for later extraction from the body. <CIT> discloses a mechanical thrombectomy device with a wire that extends distal to a catheter and is rotated to create a standing wave to break-up or macerate thrombus. <CIT> discloses a thrombectomy wire that has a sinuous shape at its distal end and is contained within a sheath in a substantially straight non-deployed position. When the sheath is retracted, the distal portion of the wire is exposed to enable the wire to return to its non-linear sinuous configuration. Actuation of the motor causes rotational movement of the wire, creating a wave pattern, to macerate thrombus. Other sinuous or s-shaped rotatory wires to disrupt clots are disclosed in <CIT> and <CIT>, and <CIT>, <CIT>, and <CIT>. The abovementioned devices are not intended to pass through tortuous pathways found in the fragile brain vessels as they would release clot material downstream leading to strokes, or the actuation of the macerating mechanism disposed directly in the vascular lumen would lead to vascular damage of delicate vessels.

Another rotary thrombectomy mechanism is disclosed in <CIT>with a rotating longitudinal cutting element with a shaped tip disposed within an aspiration catheter. This rotating element is advanced to position after the aspiration catheter has reached the target with the help of ancillary "support elements", such as intermediate catheters. In order to advance the rotating element to position near the end of the catheter through complex anatomy, it must have sufficient stiffness to be pushed without kinking or looping. In addition, the rotational element is constructed with sufficient stiffness to serve as a cutting tool for clot maceration. The required stiffness of the rotatory elements in this prior art, along with the inability to be co-axially navigated over an inner guidewire, would preclude its use for atraumatic navigation within the vasculature beyond the tip of the aspiration catheter. Additionally, the required stiffness of the rotary element creates large radial forces against the inner wall of the catheter, leading to high friction and rapid wear of the catheter. This is especially relevant if the rotating element acquires corkscrew motion upon high speed rotation, requiring the mechanism to operate below torque load needed to generate powerful hydrodynamic vortices. <CIT> also discloses thrombectomy device of the prior art.

The prior art does not disclose a stand-alone device suitable for both navigation into narrow and highly tortuous vasculature and the ability to clear occlusive material. Such a technology would be challenging to develop as the features needed for safe intravascular navigation and concurrent clot maceration are generally contraposed.

The present teachings overcome the shortcomings of the prior art to create a device for both atraumatic navigation into tortuous vasculature and mechanical thrombectomy. The device contains a flexible navigation element that can be atraumatically deployed within complex vasculature over a guidewire. This navigation element provides "scaffolding" (based on the coupled stiffness of the guidewire inside the navigation element's lumen and the navigation element itself) to enable the coaxial advancement of larger diameter aspiration catheters to challenging targets. This navigation element can subsequently be shielded within a catheter and actuated as a "thrombectomy element" in cooperation with external vacuum to generate hydrodynamic vortices and corkscrew movements for clot removal. According to the teachings of the present invention, this technology provides an integrated mechanism for enhanced navigation into the target vessel and complete recanalization by removing the obstructive thrombus. Such a system capable of reversibly transitioning between navigation and thrombectomy modes would enable faster, more efficient and simpler removal of thromboembolic material.

Claim <NUM> defines the invention and dependent claims disclose embodiments. No surgical methods are claimed per se.

Numerous specific details are set forth such as examples of specific components, devices, and exemplary methods, to provide a thorough understanding of embodiments of the present disclosure.

Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

According to the principles of the present teachings, an aspiration catheter system <NUM> implementing hydrodynamic vortices generated by rotation of a flexible shaft <NUM> is provided having an advantageous construction and method of use that is particularly configured to generate hydraulic forces and translational movements to engage, pull-in, fragment, and/or remove clot <NUM> or other obstructing material (collectively referred to herein as "clot <NUM>") in cavities or lumens. As will be described in detail herein, flexible shaft <NUM> rotates at a high speed with uncoupled rotation of the shaft and translational motion within at least an area defined by the internal wall of catheter <NUM> within which it is disposed. Generally, flexible shaft <NUM> rotates at speeds greater than <NUM>,<NUM> RPM during thrombectomy mode. <FIG> is the pressure field on a cross section of the catheter with flexible shaft <NUM> rotating at <NUM>,<NUM> RPM from the computational fluid dynamics modelling. The rotating flexible shaft <NUM> drives the fluid surrounding it to rotate in the same direction and creates a pressure gradient across the gap between shaft <NUM> and catheter wall <NUM>. This pressure gradient pushes flexible shaft <NUM> to do orbital translation inside catheter <NUM>. This orbital translational motion, together with the hydrodynamic force and phase lag of mass elements along the length of the shaft <NUM>, induces vortex capable of causing the flexible shaft to actuate in corkscrew fashion at least partially within the catheter. In some embodiments, the rotation of flexible shaft <NUM> is not directly correlated with the translational motion of flexible shaft <NUM> inside catheter <NUM>. This translational motion of the rotating shaft can be normal, parallel, or any combination thereof with respect to a plane which is normal to the center axis of containment catheter <NUM>. In some embodiments, aspiration catheter system <NUM> comprises a vacuum source fluidly coupled to catheter <NUM>.

With particular reference to <FIG>, in some embodiments, aspiration catheter system <NUM> comprises flexible shaft <NUM> disposed within catheter <NUM>. Catheter <NUM> can be selectively coupled to a catheter connection point <NUM>. Catheter connection point <NUM> enables catheter <NUM> to be selectively removed, replaced, or otherwise manipulated relative to the remaining portions of aspiration catheter system <NUM>. In some embodiments, catheter connection point <NUM> permits independent rotation of catheter <NUM> with regard to the rest of aspiration catheter system <NUM> to improve navigation ability.

Catheter connection point <NUM> can be attached or integrally formed with a vacuum port assembly <NUM> having a vacuum port <NUM> and an adjustable catheter sliding lock <NUM>. Vacuum port <NUM> is operably coupled to a vacuum source <NUM> for exerting a vacuum pressure within catheter <NUM> and at a distal end <NUM> of catheter <NUM> to suck clot <NUM> into distal end <NUM> of catheter <NUM> and into vacuum port <NUM> in accordance with the principles of the present teachings. In some embodiments, the vacuum pressure is delivered in dynamic fashion by changing pressures at different frequencies between approximately. <NUM> and <NUM> with magnitude between approximately -<NUM> kPa to -<NUM> kPa. In some embodiments, the vacuum pressure is constant.

In some embodiments, catheter sliding lock <NUM> enables customizable spacing of flexible shaft <NUM> and the distal end <NUM> of catheter <NUM>. In some embodiments, catheter sliding lock <NUM> can be adjusted such that a distal end <NUM> of flexible shaft <NUM> is within a maximal clot busting zone without protruding beyond it. In some embodiments, distal end <NUM> of flexible shaft <NUM> does not extend beyond distal end <NUM> of catheter <NUM>. This is particularly useful in applications where contact of flexible shaft <NUM> and the associated tissue is to be avoided. In some embodiments, distal end <NUM> of flexible shaft <NUM> extends beyond distal end <NUM> of catheter <NUM>. This is particularly useful in applications where contact of flexible shaft <NUM> and the associated tissue is desired.

In some embodiments, vacuum port assembly <NUM> is coupled to telescoping hypotubes <NUM> that permit a shaft advancement slider <NUM> to move flexible shaft <NUM> along the longitudinal axis of catheter <NUM> to facilitate navigation of distal end <NUM> of catheter <NUM>. In some embodiments, the shaft advancement slider <NUM> enables the flexible shaft <NUM> to extend beyond the distal tip <NUM> of catheter <NUM> by a distance of greater than at least <NUM>, preferably at least <NUM>. Hypotubes <NUM> can extend along a telescoping hypotube seal <NUM> that allows the hypotubes <NUM> to telescope while maintaining a seal to help prevent vacuum loss (by preventing vacuum loss in all parts of the device besides distal end <NUM> of catheter <NUM>, thereby maximizing the vacuum and thrombectomy power at distal end <NUM> of catheter <NUM>. A hypotube clamp <NUM> secures telescoping hypotubes <NUM> to shaft advancement slider <NUM> for facilitation by an operator. More particularly, shaft advancement slider <NUM> enables the user to selectively advance flexible shaft <NUM> beyond distal end <NUM> of catheter <NUM>, thereby helping to facilitate navigation in the vessels. <FIG> illustrates flexible shaft <NUM> and a guidewire <NUM> advanced beyond distal end <NUM> of catheter <NUM> for navigation. <FIG> illustrates guidewire <NUM> removed and flexible shaft <NUM> locked into position within catheter <NUM> for thrombectomy.

With reference to <FIG>, <FIG>, and <FIG>, a drive system <NUM> is provided for rotatably driving flexible shaft <NUM> (e.g. providing rotational energy) in accordance with the principles of the present teachings. In some embodiments, drive system <NUM> comprises a motor <NUM> having an output shaft <NUM> operably coupled to a gear set <NUM> operably coupled to flexible shaft <NUM>. In some embodiments, for improved packaging and efficiency, motor <NUM> is disposed within an internal space of shaft advancement slider <NUM>. Flexible shaft <NUM> and/or gear set <NUM> can be rotatably supported by one or more bearings <NUM>.

The components of aspiration catheter system <NUM> can be contained within a handheld, or other appropriately sized, housing <NUM>.

With particular discussion relating to flexible shaft <NUM>, it should be understood that in some embodiments flexible shaft <NUM> has sufficient flexibility to permit it to be bent or curved around tight corners (typically a radius of curvature smaller than <NUM>) and turn angles as large as <NUM> degrees without inducing permanent deformation. In some embodiments, flexible shaft <NUM> is torque resistant such that flexible shaft <NUM> can transmit high rotational energy from drive system <NUM> to clot <NUM> without failure.

To this end, as illustrated in <FIG>, flexible shaft <NUM> can be solid, hollow, or a combination thereof, and/or braided or single stranded, or a combination thereof. Hollow and/or braided configurations can increase flexibility and torque resistance while assuring high transmission efficiency of rotational energy. In configurations employing a hollow flexible shaft <NUM> (see <FIG>), guidewire <NUM> can extend within hollow flexible shaft <NUM> (see <FIG>) to facilitate navigation of distal end <NUM> of flexible shaft <NUM> and/or catheter <NUM> through the vasculature and/or can extend within a hollow portion <NUM> of catheter <NUM> formed in a sidewall thereof (see <FIG>). In some embodiments, guidewire <NUM> can include a defined shape at its distal end <NUM>, such as a J, U, or other shape, if desired, to facilitate intravascular navigation. Guidewire <NUM> can optionally be steerable and be advanced outside flexible shaft <NUM> and outside distal end <NUM> of catheter <NUM> to facilitate advancement of flexible shaft <NUM> and catheter <NUM> into clot <NUM> and into the target vessel. Furthermore, flexible shaft <NUM> can also be selectively advanced beyond distal end <NUM> of catheter <NUM> and along the guidewire, creating additional scaffolding to help facilitate the advancement of catheter <NUM> to the desired position. Upon advancement of catheter <NUM> in the desired position, flexible shaft <NUM> can be withdrawn toward distal tip <NUM> of catheter <NUM> and even completely inside catheter <NUM> and the guidewire <NUM> can be withdrawn into flexible shaft <NUM> or completely outside the device as needed. Then, flexible shaft <NUM> is rotated at high speed to perform thrombectomy as described herein.

In a preferred embodiment, in a particular device and operation the same flexible shaft <NUM> is used as "navigation element", "scaffolding element" and "thrombectomy element. " These functions can be reversibly transitioned among them. This can be achieved through using a flexible and hollow shaft <NUM> that can be linearly actuated by shaft advancement slider <NUM> and be coupled as needed with a co-axial guidewire <NUM>, and actuated by a drive system <NUM> at different modalities and intensities.

The flexible shaft <NUM> is preferably smooth and has a tapered distal end (distal portion is preferably smaller in diameter compared to the proximal end). This flexible shaft <NUM>, when acting as a "navigation element", can be atraumatically advanced over a guidewire beyond the distal catheter opening (preferably at least <NUM>) into complex and highly tortuous vasculature. The use of a coaxial inner guidewire <NUM> can improve the ability of the shaft <NUM> to advance inside the catheter without kinking or looping which could prevent it from reaching the distal tip of the catheter and could also damage the shaft <NUM>. When flexible shaft <NUM> is acting as a "navigation element", it can be provided with oscillating, rotational, translational, or vibrational motion, generated by the drive system <NUM> and/or the operators hand. This powered "navigation element" can aid in the placement of guidewire <NUM>, flexible shaft <NUM>, and/or catheter <NUM> by reducing the friction between these coaxial elements and themselves and the vasculature. This will facilitate the aspiration catheter system <NUM> to advance through tortuous geometry, advance through irregular lumens and or stenosed geometry and facilitate advancement of a larger catheter.

The shaft <NUM> can serve as a "scaffolding element" by enabling the coaxial over-the-shaft advancement of catheter <NUM> to challenging targets in a manner substantially equivalent to an intermediate catheter. Although the flexible shaft <NUM> may be too flexible to allow standalone over-the-shaft advancement of catheter <NUM>, the combination of the shaft <NUM> with an inner guidewire <NUM> can provide sufficient structure and stiffness for over-the-shaft advancement of the catheter <NUM>. The advancement of the catheter <NUM> over the shaft <NUM> can be facilitated by one or a combination of oscillating, rotational, translational, or vibrational motion of the shaft <NUM>, the catheter <NUM> or a combination of both, powered by the drive system <NUM> or the hands of the operator. The guidewire <NUM>, the shaft <NUM> and the catheter <NUM> can be longitudinally translated in coupled or uncoupled fashion, simultaneously or sequentially. By way of example, some or all of these devices can move with respect to some or all of the other devices.

After the aspiration catheter <NUM> is placed in the target, generally in proximity or within the clot mass, in the preferred embodiment the shaft <NUM> is shielded within the catheter <NUM>, the guidewire <NUM> at least partially removed from the shaft lumen and the shaft <NUM> actuated by the drive system <NUM> as a "thrombectomy element" to generate a hydrodynamic vortex with a steep oblique pressure gradient, as shown in <FIG>. In some embodiments, as illustrated in <FIG>, flexible shaft <NUM> can be composed of multiple segments with different diameters and winding combinations. That is, flexible shaft <NUM> can comprise a first segment <NUM> and a second segment <NUM> (or additional segments). This allows flexible shaft <NUM> to be optimized for key parameters, such as torsional strength at the proximal end, flexibility at the distal tip, and contraction/elongation tendency of the shaft during navigation and high speed rotation (acts like a spring that can wind up, tightening and shortening the shaft <NUM>, or unwind, elongating the shaft <NUM>). In some embodiments the windings of shaft <NUM> are in opposite directions. In some embodiments, flexible shaft <NUM> comprises a larger diameter wind at the proximal end for torsional strength (in a preferred embodiment for a catheter with ID between <NUM>"-<NUM>", the shaft <NUM> OD is between <NUM>-<NUM>" with an ID of between <NUM>-<NUM>" and a bending stiffness of approximately between <NUM> N mm^<NUM> and <NUM> N mm^<NUM>, where bending stiffness is defined as Young's modulus multiplied by the area moment of inertia of the flexible shaft <NUM>) and a smaller diameter wind at and near the distal tip (typically between <NUM>-<NUM>" OD with an ID of between <NUM>-<NUM>" and a bending stiffness of approximately between <NUM> N mm^<NUM> and <NUM> N mm^<NUM>) to help navigate through tortuous vessels. This lower bending stiffness distal length preferably extends between <NUM>"- <NUM>" from the distal tip <NUM> of flexible shaft <NUM>. It should be appreciated, as illustrated in <FIG>, that multiple shaft <NUM> segment configuration can be achieved by varying the cross-sectional size of the wire used to construct flexible shaft <NUM> from a diameter dp to a diameter dd, where diameter dp is larger, smaller, or different than diameter dd. Moreover, multiple layers of windings can be added to achieve various torsional and bending stiffness (see <FIG>). Furthermore, different materials could be used to achieve different shaft stiffness. These materials are commonly stainless steel or nitinol. Centerless grinding can also be used to reduce the outer diameter of flexible shaft <NUM> in certain sections to reduce the stiffness of that shaft segment.

The outer diameter of flexible shaft <NUM> is preferably <NUM>-<NUM>% of the inner diameter of aspiration catheter <NUM>. Larger shafts <NUM> tolerate higher torque and bending force during thrombectomy and facilitate atraumatic coaxial advancement of the catheter <NUM>. However, larger shafts <NUM> tend to cause drop in vacuum power and may not advance easily over a guidewire <NUM> into the intravascular space during navigation. Smaller shaft <NUM> may navigate easier and minimize vacuum power loss although may not provide enough structure for coaxial advancement of catheter <NUM> or resist the torque load needed for vortices generation.

In some embodiments, the same shaft <NUM> could have different zones to optimize torque resistance and rotational energy by a combination of features described herein. These zones could be created by welding, gluing, grinding, or other methods known to those skilled in the art. The changes in shaft design could be a continuous transition, a step-wise transition, or a combination of both. For example, at the base of flexible shaft <NUM> closest to the drive system <NUM>, the winding of flexible shaft <NUM> could be very tight and potentially include a larger diameter to help resist to the high torsional forces that are typically experienced at that location. Then, toward the distal end of flexible shaft <NUM>, the winding of flexible shaft <NUM> and/or diameter of flexible shaft <NUM> could be progressively diminished as smaller torsional forces are typically experienced near the distal end. This can act to enhance the flexibility and/or diminish flexible shaft <NUM> diameter while optimizing delivery of rotational energy to enable thrombectomy.

In some embodiments, flexible shaft <NUM> can be a continuous structure or can be formed by multiple segments. These segments could be connected to one another using, for example but not limited to, adhesives, welding, or other joints that allow transmission of rotational forces.

The coiling density (coils/length/number and thickness of filars) of flexible shaft <NUM> can be different within different flexible shafts or along the length of the same shaft. In one embodiment there are between <NUM> and <NUM> filars with a thickness between <NUM>-<NUM>". Typically, a larger filar count and larger filar thickness corresponds to a stiffer and stronger shaft whereas a smaller filar count and a smaller filar thickness corresponds to a more flexible and compliant shaft with lower bending stiffness. Additionally, a shaft with a larger outer diameter will typically have higher stiffness and torsional strength when compared to a shaft with a smaller outer diameter.

The cross-sectional design of flexible shaft <NUM> can be of a variety of different geometrical shapes, with examples of shapes including but not limited to circular, triangular, square and others. The cross-sectional design of flexible shafts can be different within different shafts or along the length of the same shaft. Therefore, it should be recognized that flexible shaft <NUM> (and catheter <NUM>) do not need to have constant diameter along the total length of the device. In some instances, it would be beneficial to increase shaft and catheter diameter in the proximal end where high strength and pushability, or the ability for an object to be pushed/advanced without kinking or looping, but less flexibility is required. In one embodiment the outer diameter of the proximal end of flexible shaft <NUM> is approximately <NUM>" with approximately <NUM> filar windings while the distal end is approximately <NUM>" with <NUM> filar windings. In other instances, it would be beneficial to increase the diameter of catheter <NUM> toward the distal end to enhance vacuum efficiency and thrombectomy efficacy.

In some embodiments, the flexibility and torque resistance of flexible shaft <NUM> can be modified by changing diameter, material, geometric, and braiding features of flexible shaft <NUM> and/or by introducing a guidewire <NUM> with different stiffness within flexible shaft <NUM>.

In some embodiments, flexible shaft <NUM> is made of metal, such as stainless steel. It can be made through winding stainless steel filament around a mandrel to produce a hollow shaft. The shaft <NUM> preferably includes a hollow channel to enable a guidewire <NUM> to be coaxially advanced within the flexible shaft <NUM> for system navigation, while simultaneously achieving sufficient torsional strength to resist breaking during use.

In some embodiments, flexible shaft <NUM> could be composed of multiple lumens that are either connected, un-connected, or a combination thereof to one another. As an example, there could be three shafts, each with their own lumen, that are combined to form an additional lumen where a guidewire can be slid through.

In some embodiments, as illustrated in <FIG> and <FIG>, flexible shaft <NUM> comprises one or more hydraulic inducing features <NUM> that enhance hydraulic forces during rotation of flexible shaft <NUM>. Hydraulic enhancing features <NUM> can include, but are not limited to, fins, bumps, ridges, and surface micro features, either along the entire shaft of flexible shaft <NUM>, near distal end <NUM> of flexible shaft <NUM>, or attached to distal end <NUM> of flexible shaft <NUM>. In some embodiments, hydraulic enhancing features <NUM> increase hydraulic force to enhance destruction and/or maceration of clot <NUM>.

In some embodiments, as illustrated in <FIG>, <FIG>, and <FIG>, flexible shaft <NUM> comprises one or more eccentric features <NUM> to further induce translational motion of flexible shaft <NUM> to enhance the thrombectomy mechanism. It should be understood that in some embodiments hydraulic enhancing features <NUM> and eccentric features <NUM> may be the same feature performing both functions. These eccentric features <NUM> could be in the form of an eccentrically wound shaft, an eccentric mass fixed to part of flexible shaft <NUM>, an eccentric tip on flexible shaft <NUM>, or a combination thereof. An ideal eccentric feature <NUM> will be minimal in size so as to not significantly decrease the flexibility of flexible shaft <NUM> while still being large enough to induce translational motion in flexible shaft <NUM> during rotation. In addition, it should ideally be tapered and have an atraumatic configuration to enable safe intravascular navigation of the shaft. This eccentric feature could be of any length and disposed at any point or several points along the length of flexible shaft <NUM>, and may even extend beyond the distal most end of flexible shaft <NUM>.

In another embodiment, an off-center channel at least partially along the shaft <NUM> or the shaft tip <NUM> would create eccentric features.

Flexible shaft <NUM> could also have features including but not limited to an abrasive coating, surface micro features and patterning to augment friction between flexible shaft, the fluid environment <NUM> and clot <NUM>. This would translate into stronger hydrodynamic waves and grasp of clot <NUM> by flexible shaft <NUM> resulting in enhanced corkscrew inward traction of clot <NUM> into catheter <NUM>.

Flexible shaft <NUM> could also have features including but not limited to a lubricious coating in the outer and/or inner lumens at least partially along its length to reduce friction between the shaft <NUM>, the guidewire <NUM> and the catheter <NUM>.

Flexible shaft <NUM> can be advanced or withdrawn to optimize its position into the maximal thrombectomy zone <NUM> to optimize the interaction between shaft and clot <NUM> in the engagement zone. In addition, it can be completely withdrawn from catheter <NUM> and exchanged if needed.

The advancement or retraction of flexible shaft <NUM>, guidewire <NUM>, and/or catheter <NUM> can be enhanced by very low speed rotation (typically <<NUM> rpm), vibration or oscillation (typically greater than <NUM>) of flexible shaft <NUM> by the user's hand or a drive system <NUM>. It should be noted that this operation mode is for device navigation. For thrombectomy, the preferred embodiment is with flexible shaft <NUM> fully contained within catheter <NUM> and rotated at higher speeds as set forth herein.

In some embodiments, flexible shaft <NUM> can be navigated into the vasculature as described herein, and then used as scaffolding to advance a catheter over-a-shaft. The advancement or retraction of catheter <NUM> can be enhanced by very low speed rotation (typically <<NUM> rpm), vibration, or oscillation (typically greater than <NUM>) of catheter <NUM> by the user hand or a motor (same or different motor than motor causing high speed rotation for vortex generation). The same shaft could have different zones to optimize scaffolding by a combination of features mentioned above.

In some embodiments, as illustrated in <FIG> and <FIG>, flexible shaft <NUM> comprises a shaft tip <NUM> that is connectable, coupled, or otherwise extending from distal end <NUM> of flexible shaft <NUM>. In some embodiments, shaft tip <NUM> can be rounded and have smooth atraumatic edges <NUM> during navigation in the vessel, and have one or more sharp edges <NUM> during thrombectomy mode. This can be achieved by, but not exclusively by: <NUM>) including grooves in an angled position, resulting in two edges, one sharp and the other dull (see <FIG>). When flexible shaft <NUM> rotates clockwise, the sharp edge moves forward to engage and cut clot <NUM> (active thrombectomy mode). When flexible shaft <NUM> rotates counter-clockwise (navigation mode) the sharp edge moves away from the surrounding tissue facilitating shaft advancement into the vascular lumen by low-speed rotation. Shaft tip <NUM> can be otherwise rounded or smooth to facilitate advancement with the introduction of the guidewire <NUM> for navigation mode. In some embodiments, shaft tip <NUM> includes a lumen in the tip that is co-axially oriented to the main longitudinal axis of flexible shaft <NUM> with a taper that varies in steepness through the circumference of the tip gradient, resulting in a smooth and rounded tip with the introduction of the guidewire <NUM> for navigation mode, and a "spoon" notch in flexible shaft <NUM> tip for clot <NUM> maceration upon wire removal. It should be noted that the latter two embodiments, or any variations of such embodiments, create an off-center mass that will enhance orbital movement of flexible shaft <NUM> and vortex generation upon rotation at high speed. As the outer diameter of guidewire <NUM> is smaller than shaft inner diameter, the off-center mass can be enhanced by shifting the lumen of the tip away from the longitudinal axis of flexible shaft <NUM>.

In some embodiments, catheter <NUM> is configured to be navigated through vascular geometries, and is made from pliable material. In some embodiments, catheter <NUM> is made sufficiently stiff to not collapse under suction force or kink upon small bending radius. In some embodiments, catheter <NUM> is structurally reinforced to prevent kinking of the lumen with bending.

In some embodiments, wall surface <NUM> of catheter <NUM> has a hollow channel that spans the length of catheter <NUM> and opens distally. This hollow channel enables a guidewire <NUM> to be disposed within the wall of catheter <NUM> (<FIG>). This guidewire <NUM> can optionally be steerable and be advanced outside the distal end of catheter <NUM> into the vascular lumen to facilitate and direct advancement of catheter <NUM> into the mass of clot <NUM> and into the target vessel, both before, during, or after mechanical thrombectomy by powering flexible shaft <NUM> in catheter <NUM> as described herein.

In some embodiments, as illustrated in <FIG>, the combination of flexible shaft <NUM> and catheter <NUM> can define one or more zones that are particularly adapted and configured to perform mechanical thrombectomy upon clot <NUM>. As disclosed herein, flexible shaft <NUM> is positioned within catheter <NUM> and is rotating at a very high speed to create hydrodynamic vortices and corkscrew movements to further disrupt clot <NUM>. Generally, a clot engager zone <NUM> is located from distal end <NUM> of catheter <NUM> and proximally extends within catheter <NUM> to a location <NUM> proximal from distal end <NUM> of flexible shaft <NUM>. A maximal thrombectomy zone <NUM> is further proximally located relative to clot engager zone <NUM>, although maximal thrombectomy zone <NUM> can overlap clot engager zone <NUM> to some, all or no extent. Maximal thrombectomy zone <NUM> can be bound at a distal end <NUM> (extending distally past distal end <NUM> of flexible shaft <NUM>) and a proximal end <NUM> (extending proximally relative to distal end <NUM> of flexible shaft <NUM>). An anti-clog zone <NUM> is still further proximally located relative to maximal thrombectomy zone <NUM> and generally extends within catheter <NUM>.

In some embodiments, the distal most segment (e.g. clot engager zone <NUM>) of catheter <NUM> may be at an angle to the longitudinal axis of catheter <NUM>.

Clot engager zone <NUM> anchors clot <NUM> to catheter <NUM> optimizing the thrombectomy mechanisms described herein. In addition, clot engager zone <NUM> maintains clot <NUM> anchored to catheter <NUM>, minimizing release of free fragments. The combination of shaft orbital translation, shaft transverse vibration, and torsional indraft pull following a corkscrew pathway due to pressure gradient, flow shear, and contacting force between flexible shaft <NUM> and contacting clot <NUM>, and vacuum overlapping at clot engager zone <NUM> provides a synergetic thrombectomy milieu that is safely contained within catheter <NUM>. In addition, clot engager zone <NUM> provides a safety buffer zone to allow the periodic elongation and contraction of flexible shaft <NUM> when it is rotated at high speed, such that flexible shaft <NUM> is not disposed on the outside of catheter <NUM> where it can potentially cause damage to the blood vessels or body cavity.

In some embodiments, at least the maximal thrombectomy zone <NUM> of catheter <NUM> will have a reinforced segment <NUM> to increase the structural resistance of catheter <NUM> to forces and energy transmitted by the motion of flexible shaft <NUM>, as shown in <FIG>. This segment <NUM> can be coated with anti-abrasive material. In some embodiments, distal end <NUM> of catheter <NUM> and maximal thrombectomy zone <NUM> can be structurally reinforced to prevent collapse of the lumen of catheter <NUM> with vacuum.

In some embodiments, at least the maximal thrombectomy zone <NUM> of catheter <NUM> comprises fluoroscopic markers to aid in the positioning of distal end <NUM> of flexible shaft <NUM> in optimal position for activation.

In some embodiments, fluoroscopic markers, CT and MRI markers can be provided in any portion of catheter <NUM>, guidewire <NUM>, and/or flexible shaft <NUM>.

In some embodiments, distal end <NUM> of catheter <NUM> includes one or more uneven features <NUM> disposed thereon (e.g. rounded bumps). In some embodiments, features <NUM> can be along the same direction as the long axis of catheter <NUM>. Features <NUM> help to penetrate and break apart clot <NUM> due to concentrated areas of high shearing force as clot <NUM> is dragged inward into maximal thrombectomy zone <NUM> following a corkscrew path.

In some embodiments, as illustrated in <FIG> and <FIG>, catheter <NUM> may have accessory lumen, channel, or holes <NUM> in the wall to allow fluid (saline solution, blood, medication, etc.) to fill the lumen of catheter <NUM> preventing cavitation upon vacuum and maintain the environment needed to generate hydrodynamic forces, and aid in removal of material. Moreover, in some embodiments, as illustrated in <FIG>, <FIG>, and <FIG>, catheter <NUM> may have accessory lumen or channel <NUM> throughout the totality or part of its extension to allow guidewire <NUM> or other wire to be disposed within for navigation or to infuse solutions or medications. Particularly, as illustrated in <FIG>, a channel <NUM> can be disposed within the sidewall of catheter <NUM> to deliver a fluid. As illustrated in <FIG>, channel <NUM> can extend along an ancillary channel of catheter <NUM>. In some embodiments, the fluid can be delivered through the hollow interior of flexible shaft <NUM> (<FIG>).

In some embodiments, wall surface <NUM> of catheter <NUM> has a hollow channel that spans at least part of the length of catheter <NUM> and opens at the distal end of catheter <NUM>, into the lumen of catheter <NUM>, or a combination thereof. This hollow channel enables the advancement of a guidewire <NUM> to be used in monorail system, both during navigation mode of catheter <NUM> (with or without co-axial advancement over a shaft) and thrombectomy mode. In the latter option, flexible shaft <NUM> is rotating at very high speed inside catheter <NUM> causing clot <NUM> engagement and fragmentation while catheter <NUM> is advanced or pulled back over the monorail wire disposed in the vascular lumen, and not in contact with flexible shaft <NUM> (<FIG>).

In some embodiments, wall surface <NUM> of catheter <NUM> has a hollow channel that spans at least part of the length of catheter <NUM> and opens at the distal end of catheter <NUM>, into the lumen of catheter <NUM>, or a combination thereof. This hollow channel enables the advancement of a distal embolization protection device, such as a net or filter, that can be advanced through clot <NUM> mass and: <NUM>) be pulled back facilitating entrance of clot <NUM> into catheter <NUM>; <NUM>) remain distal to clot <NUM> to capture embolization particles and then be pulled back allowing these particles to be removed by catheter <NUM>.

In some embodiments, wall surface <NUM> of catheter <NUM> has a hollow channel that spans at least part of the length of catheter <NUM> and opens at the distal end of catheter <NUM>, into the lumen of catheter <NUM>, or a combination thereof. This hollow channel enables the advancement of an occlusive device, such asas a balloon, which can be advanced through clot <NUM> mass and then: <NUM>) insufflated to prevent distal embolization by stopping anterograde flow, <NUM>) be pulled back facilitating entrance of clot <NUM> into catheter <NUM>.

In some embodiments, wall surface <NUM> of catheter <NUM> or flexible shaft <NUM> can have a hollow channel to deliver medication, cooling fluids or other agents toward the distal end of catheter <NUM>.

In some embodiments, catheter <NUM> may have a flow occlusion mechanism, such as one or more balloons, near or at the distal end <NUM> to enhance suction force applied to the region of interest, reduce the pressure upon which the material needs to be removed, and diminish or stop flow minimizing distal embolism.

In some embodiments, catheter <NUM> includes a filter device for capturing undesirable material and removing it from the fluid flow.

The rotation of flexible shaft <NUM> contained within catheter <NUM> induces key engagement and fragmentation mechanisms (see <FIG>, <FIG>, <FIG>, <FIG>), such as, but not limited to:.

In some embodiments, to enhance the axial force of the rotating shaft <NUM>, magnets can be added the catheter <NUM> and flexible shaft <NUM> such that when flexible shaft <NUM> is rotated with respect to catheter <NUM>, the poles of the opposing magnets periodically attract and repel one another.

In some embodiments, the system may include a reinfusion cannula to reintroduce the fluid remove from the patient back into the patient.

In some embodiments, to enhance the hydrodynamic force on the rotating shaft <NUM>, hydrophilic coatings can be applied to shaft <NUM>.

With reference to <FIG>, in some embodiments during clot maceration and removal, guidewire <NUM> is advanced within the lumen of the vessel/cavity/space to clot <NUM> (<FIG>). Distal end <NUM> of flexible shaft <NUM> is then advanced along guidewire <NUM> and placed in proximity or within the mass of clot <NUM> (<FIG>). The longitudinal displacement of the shaft <NUM> can be facilitated by low speed rotation, oscillation or vibration by the dive system <NUM>. Distal end <NUM> of catheter <NUM> is then navigated into the target vessel/cavity/space and placed in proximity or within the mass of clot <NUM> (<FIG>). During this navigation and positioning, it can also be advantageous to retract shaft <NUM> in cooperation with the advancement of catheter <NUM>. This can be achieved through manual or automatic retraction actuation of shaft advancement slider <NUM> in cooperation with manual or automatic advancement of catheter <NUM> by means of vacuum port assembly <NUM> and/or aspiration catheter system <NUM>. In some embodiments, catheter <NUM> can be further supported internally and/or externally using additional supporting elements such as a guiding catheter, an introducer, or combinations thereof. Guidewire <NUM> can be retracted or fully removed from the vessel or aspiration catheter system <NUM>. Flexible shaft <NUM> is positioned in catheter <NUM> to reach maximal thrombectomy zone <NUM> (<FIG>). Suction from vacuum source <NUM> begins and draws clot <NUM> portion into clot engager zone <NUM> of catheter <NUM> either prior, concurrent and/or after the flexible shaft <NUM> is rotated at high speed in accordance with the principles of the present teachings. Thrombectomy is fully contained within catheter <NUM> as described herein. Catheter <NUM> and clot <NUM> remain engaged during the thrombectomy stage (<FIG> and <FIG>). Suction continues and clot <NUM> enters further into maximal thrombectomy zone <NUM> of catheter <NUM>. Flexible shaft <NUM> is further rotated inside catheter <NUM> at high speed generating thrombectomy by the mechanisms described herein. However, as needed during the thrombectomy procedure, the rotation of flexible shaft <NUM> can be momentarily stopped and once again become the navigation and scaffolding element if needed. The fragmented clot <NUM> inside catheter <NUM> is continuously aspirated away from the vascular lumen and undergoes further fragmentation along the total length of catheter <NUM> by the mechanisms described herein.

In some embodiments, fragmentation and/or maceration of clot <NUM> are only active in maximal thrombectomy zone <NUM> (<FIG>). Simultaneously, unfragmented clot <NUM> is dragged inwards into clot engager zone <NUM> and then further into maximal thrombectomy zone <NUM> for further thrombectomy as described herein.

In some embodiments, the action of thrombectomy and maceration in <FIG> results in catheter <NUM> advancing into the substance of clot <NUM> and distally into the target vessels until complete removal of clot <NUM> is achieved (<FIG>).

In some embodiments, as illustrated in <FIG>, a secondary wire <NUM> can be used to guide catheter <NUM> and flexible shaft <NUM> during thrombectomy. The secondary wire <NUM> can be located in channel <NUM> of catheter <NUM> or along a channel thereof.

In some embodiments, flexible shaft <NUM> can be actuated at or near the proximal end of flexible shaft <NUM> to induce translational motion at least at the distal end of catheter <NUM>. This can be used both exclusively and in conjunction with the rotational motion to increase thrombectomy capability.

In some embodiments, shaft <NUM> can be rotated at high speed outside (e.g. beyond) distal end <NUM> of catheter <NUM> following orbital movements that extend along a path that could be larger than the diameter of catheter <NUM>. The diameter of this orbital movement of shaft <NUM> outside catheter <NUM> is dependent upon the rotational speed, the length of shaft <NUM> protruding outside catheter <NUM>, the ID of catheter <NUM>, and the flexibility of shaft <NUM>. The translational movement of a shaft <NUM> with enough stiffness to act as cutting tool will generate a cutting cone to fragment tissues and clots <NUM>. This can be coupled with vacuum to removed fragmented debris. This can be coupled by a bipolar mechanism (between an electrified shaft or shaft tip and catheter <NUM> distal-most opening) to induce bipolar current and simultaneous coagulation during tissue maceration. This can also be coupled to hollow channel <NUM> along the wall of catheter <NUM> that enables a fluid media to be delivered at or near the distal end of catheter <NUM> which can then backfill catheter <NUM> lumen by vacuum. This would enable the generation of hydraulic forces and translational shaft motions when catheter <NUM> is not already immersed into a liquid environment.

In some embodiments, the method for removing undesirable material from within a vessel can comprise obtaining endovascular access percutaneously or by cut down and introducing a sheath. The thrombectomy system is then introduced through the sheath into the endovascular space. The guidewire <NUM> or the secondary wire <NUM> is advanced to the clot <NUM> and the flexible shaft <NUM> is advanced to the clot. In some embodiments, the flexible shaft <NUM> is advanced over the guidewire <NUM>. The catheter <NUM> is then advanced over the flexible shaft <NUM> and/or guidewire <NUM> to the clot <NUM>. The guidewire <NUM> can then be removed partially or totally. The catheter <NUM> and/or flexible shaft <NUM> is then positioned such that the flexible shaft <NUM> is fully contained within the catheter <NUM>. Vacuum is then provided to the aspiration catheter system. The thrombectomy mechanism is the activated while the catheter is stationary or moving longitudinally in the vascular lumen. If secondary wire <NUM> is used, the catheter is moved longitudinally over the secondary wire <NUM> while thrombectomy mechanism is active. If proximal occlusion mechanism is used: inflate balloon, then activate thrombectomy. If distal occlusion mechanism is used: inflate balloon, then activate thrombectomy. Distal balloon of filter can be pulled back into catheter before, during, or after the thrombectomy enhancing clot-catheter interaction.

Claim 1:
An aspiration catheter system for use in thrombectomy of a thrombus, the aspiration catheter system comprising:
a tubular catheter member (<NUM>) having an open distal end (<NUM>) and an inner diameter defining a catheter lumen;
a vacuum source (<NUM>) operably coupled to the tubular catheter member to impart a vacuum within the catheter lumen to aspirate the thrombus;
a rotational drive system (<NUM>); and
a flexible shaft (<NUM>) operably coupled to the rotational drive system (<NUM>) and being disposed within the catheter lumen, the rotational drive system configured to apply a rotational driving force to the flexible shaft (<NUM>) to rotate the flexible shaft (<NUM>) and induce rotational and orbital motion inside the catheter lumen, the flexible shaft (<NUM>) configured to acquire a corkscrew configuration in response to the rotational driving force that results in the formation of hydrodynamic vortices within the catheter lumen.