CROSS-REFERENCE TO RELATED APPLICATIONS

[1] This application claims the benefit of U.S. Provisional Application No. 62/483,580, filed on April 10, 2017. The entire disclosure of the above application is incorporated herein by reference.

FIELD

[2] 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. BACKGROUND AND SUMMARY

[3] This section provides background information related to the present disclosure, which is not necessarily prior art. This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

[4] 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 1 ) obstruction of arteries of delicate organs, such as the heart or the brain; 2) large clots interrupting blood flow in major vessels or causing severe symptoms; or 3) when systemic delivery of the drugs is too risky.

[5] 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.

[6] Modification of catheter shape has been suggested or disclosed in the prior art to enhance aspiration of intravascular clots. In U.S. Patent No. 8,075,510 to Aklog et al., 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.

[7] 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 U.S. Patent No. 5, 135,482 to Neracher, 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 U.S. Patent No. 6,676,637 to Bonnette et al. 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.

[8] 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. U.S. Patent No. 5,876,414 to Straub 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. U.S. Patent No. 6,238,405 to Findlay 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. U.S. Patent No. 5,695,507 to Auth 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 500 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. U.S. Patent No. 6,090, 1 18 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. U.S. Patent Publication No. 2002/0173812 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 U.S. Patent Nos. 9,282,992 and 6,926,725, and U.S. Patent Application Publication Nos. 2004/0006306, 2017/0007290, and 2017/0007290. 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.

[9] Another rotary thrombectomy mechanism is disclosed in US 2016/0166266 by Nita 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.

[10] 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.

[11] 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.

[12] Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. DRAWINGS

[13] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. [14] FIG. 1 is an exploded perspective view illustrating an aspiration catheter system according to the principles of the present teachings.

[15] FIG. 2 is a side view of the aspiration catheter system according to the principles of the present teachings with the guidewire installed and the navigation element extended beyond the distal tip of the aspiration catheter.

[16] FIG. 3 is a side view of the aspiration catheter system according to the principles of the present teachings with the guidewire removed and the navigation element retracted at the distal opening or within the aspiration catheter.

[17] FIG. 4 is a cross-sectional view illustrating the aspiration catheter system according to the principles of the present teachings.

[18] FIG. 5 is a cross-sectional view illustrating the telescoping hypotube seal according to the principles of the present teachings.

[19] FIG. 6 is a cross-sectional view illustrating the gear set according to the principles of the present teachings.

[20] FIGS. 7A-7D are schematic end views illustrating a flexible shaft disposed within a catheter according to the principles of the present teachings.

[21] FIG. 8A is a perspective view of a flexible shaft according to some embodiments of the present teachings.

[22] FIG. 8B is a side view of the flexible shaft of FIG. 8A disposed in a catheter according to some embodiments of the present teachings.

[23] FIGS. 8C-8D are schematic cross-sectional views illustrating varying profiles of the flexible shaft.

[24] FIGS. 9A-9F are perspective views and end views of a flexible shaft having hydraulic inducing features and/or eccentric features according to some embodiments of the present teachings.

[25] FIGS. 10A-10D are perspective views and end views of a flexible shaft having eccentric features according to some embodiments of the present teachings.

[26] FIGS. 1 1 A-1 1 F are perspective views and end views of shaft tips for use with the flexible shaft according to some embodiments of the present teachings.

[27] FIG. 12 is a partial cross-sectional view of the catheter and flexible shaft according to some embodiments of the present teachings.

[28] FIGS. 13A-13C are partial cross-sectional views of the catheter and flexible shaft having fluid and/or guidewire delivery systems according to some embodiments of the present teachings. [29] FIGS. 14A-14B are a partial cross-sectional views of the catheter and flexible shaft illustrating the motion responses of the catheter and flexible shaft during thrombectomy according to some embodiments of the present teachings.

[30] FIGS. 15A-15D are schematic end views illustrating motion of the flexible shaft disposed within a catheter according to the principles of the present teachings.

[31] FIG. 16A is a graph illustrating the orbital translation of the flexible shaft within the catheter during thrombectomy.

[32] FIG. 16B is a pressure gradient graph illustrating the pressure gradient created within the catheter during thrombectomy.

[33] FIGS. 17A-17G are schematic views illustrating the method according to some embodiments of the present teachings.

[34] FIGS. 18A-18D are schematic views illustrating the method according to some embodiments of the present teachings.

[35] FIGS. 19A-19G are partial cross-sectional views of the catheter and flexible shaft illustrating the corkscrew or helical motion of the flexible shaft during thrombectomy according to some embodiments of the present teachings.

[36] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. DETAILED DESCRIPTION

[37] Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well- known device structures, and well-known technologies are not described in detail.

[38] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a," "an," and "the" may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "including," and "having," are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

[39] When an element or layer is referred to as being "on," "engaged to," "connected to," or "coupled to" another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly engaged to," "directly connected to," or "directly coupled to" another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.). As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

[40] Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first," "second," and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. 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.

[41] Spatially relative terms, such as "inner," "outer," "beneath," "below," "lower," "above," "upper," and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the example term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[42] According to the principles of the present teachings, an aspiration catheter system 10 implementing hydrodynamic vortices generated by rotation of a flexible shaft 12 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 100 or other obstructing material (collectively referred to herein as "clot 100") in cavities or lumens. As will be described in detail herein, flexible shaft 12 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 14 within which it is disposed. Generally, flexible shaft 12 rotates at speeds greater than 10,000 RPM during thrombectomy mode. FIG. 16A is the pressure field on a cross section of the catheter with flexible shaft 12 rotating at 90,000 RPM from the computational fluid dynamics modelling. The rotating flexible shaft 12 drives the fluid surrounding it to rotate in the same direction and creates a pressure gradient across the gap between shaft 12 and catheter wall 17. This pressure gradient pushes flexible shaft 12 to do orbital translation inside catheter 14. This orbital translational motion, together with the hydrodynamic force and phase lag of mass elements along the length of the shaft 12, 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 12 is not directly correlated with the translational motion of flexible shaft 12 inside catheter 14. 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 14. In some embodiments, aspiration catheter system 10 comprises a vacuum source fluidly coupled to catheter 14.

[43] With particular reference to FIG. 1 , in some embodiments, aspiration catheter system 10 comprises flexible shaft 12 disposed within catheter 14. Catheter 14 can be selectively coupled to a catheter connection point 16. Catheter connection point 16 enables catheter 14 to be selectively removed, replaced, or otherwise manipulated relative to the remaining portions of aspiration catheter system 10. In some embodiments, catheter connection point 16 permits independent rotation of catheter 14 with regard to the rest of aspiration catheter system 10 to improve navigation ability.

[44] Catheter connection point 16 can be attached or integrally formed with a vacuum port assembly 18 having a vacuum port 20 and an adjustable catheter sliding lock 22. Vacuum port 20 is operably coupled to a vacuum source 24 for exerting a vacuum pressure within catheter 14 and at a distal end 15 of catheter 14 to suck clot 100 into distal end 15 of catheter 14 and into vacuum port 20 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 .5 Hz and 1000 Hz with magnitude between approximately -100 kPa to -5 kPa. In some embodiments, the vacuum pressure is constant.

[45] In some embodiments, catheter sliding lock 22 enables customizable spacing of flexible shaft 12 and the distal end 15 of catheter 14. In some embodiments, catheter sliding lock 22 can be adjusted such that a distal end 13 of flexible shaft 12 is within a maximal clot busting zone without protruding beyond it. In some embodiments, distal end 13 of flexible shaft 12 does not extend beyond distal end 15 of catheter 14. This is particularly useful in applications where contact of flexible shaft 12 and the associated tissue is to be avoided. In some embodiments, distal end 13 of flexible shaft 12 extends beyond distal end 15 of catheter 14. This is particularly useful in applications where contact of flexible shaft 12 and the associated tissue is desired.

[46] In some embodiments, vacuum port assembly 18 is coupled to telescoping hypotubes 26 that permit a shaft advancement slider 28 to move flexible shaft 12 along the longitudinal axis of catheter 14 to facilitate navigation of distal end 15 of catheter 14. In some embodiments, the shaft advancement slider 28 enables the flexible shaft 12 to extend beyond the distal tip 15 of catheter 14 by a distance of greater than at least 10 mm, preferably at least 80 mm. Hypotubes 26 can extend along a telescoping hypotube seal 30 that allows the hypotubes 26 to telescope while maintaining a seal to help prevent vacuum loss (by preventing vacuum loss in all parts of the device besides distal end 15 of catheter 14, thereby maximizing the vacuum and thrombectomy power at distal end 15 of catheter 14. A hypotube clamp 31 secures telescoping hypotubes 26 to shaft advancement slider 28 for facilitation by an operator. More particularly, shaft advancement slider 28 enables the user to selectively advance flexible shaft 12 beyond distal end 15 of catheter 14, thereby helping to facilitate navigation in the vessels. FIG. 2 illustrates flexible shaft 12 and a guidewire 50 advanced beyond distal end 15 of catheter 14 for navigation. FIG. 3 illustrates guidewire 50 removed and flexible shaft 12 locked into position within catheter 14 for thrombectomy.

[47] With reference to FIGS. 1 , 4, and 6, a drive system 32 is provided for rotatably driving flexible shaft 12 (e.g. providing rotational energy) in accordance with the principles of the present teachings. In some embodiments, drive system 32 comprises a motor 34 having an output shaft 36 operably coupled to a gear set 38 operably coupled to flexible shaft 12. In some embodiments, for improved packaging and efficiency, motor 34 is disposed within an internal space of shaft advancement slider 28. Flexible shaft 12 and/or gear set 38 can be rotatably supported by one or more bearings 40.

[48] The components of aspiration catheter system 10 can be contained within a handheld, or other appropriately sized, housing 42.

FLEXIBLE SHAFT

[49] With particular discussion relating to flexible shaft 12, it should be understood that in some embodiments flexible shaft 12 has sufficient flexibility to permit it to be bent or curved around tight corners (typically a radius of curvature smaller than 10mm) and turn angles as large as 360 degrees without inducing permanent deformation. In some embodiments, flexible shaft 12 is torque resistant such that flexible shaft 12 can transmit high rotational energy from drive system 32 to clot 100 without failure.

[50] To this end, as illustrated in FIGS. 7A-7D, flexible shaft 12 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 12 (see FIGS. 7B-7D), guidewire 50 can extend within hollow flexible shaft 12 (see FIG. 7C) to facilitate navigation of distal end 13 of flexible shaft 12 and/or catheter 14 through the vasculature and/or can extend within a hollow portion 52 of catheter 14 formed in a sidewall thereof (see FIG. 7D). In some embodiments, guidewire 50 can include a defined shape at its distal end 51 , such as a J, U, or other shape, if desired, to facilitate intravascular navigation. Guidewire 50 can optionally be steerable and be advanced outside flexible shaft 12 and outside distal end 15 of catheter 14 to facilitate advancement of flexible shaft 12 and catheter 14 into clot 100 and into the target vessel. Furthermore, flexible shaft 12 can also be selectively advanced beyond distal end 15 of catheter 14 and along the guidewire, creating additional scaffolding to help facilitate the advancement of catheter 14 to the desired position. Upon advancement of catheter 14 in the desired position, flexible shaft 12 can be withdrawn toward distal tip 15 of catheter 14 and even completely inside catheter 14 and the guidewire 50 can be withdrawn into flexible shaft 12 or completely outside the device as needed. Then, flexible shaft 12 is rotated at high speed to perform thrombectomy as described herein.

[51] In a preferred embodiment, in a particular device and operation the same flexible shaft 12 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 12 that can be linearly actuated by shaft advancement slider 28 and be coupled as needed with a co-axial guidewire 50, and actuated by a drive system 32 at different modalities and intensities.

[52] The flexible shaft 12 is preferably smooth and has a tapered distal end (distal portion is preferably smaller in diameter compared to the proximal end). This flexible shaft 12, when acting as a "navigation element", can be atraumatically advanced over a guidewire beyond the distal catheter opening (preferably at least 80 mm) into complex and highly tortuous vasculature. The use of a coaxial inner guidewire 50 can improve the ability of the shaft 12 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 12. When flexible shaft 12 is acting as a "navigation element", it can be provided with oscillating, rotational, translational, or vibrational motion, generated by the drive system 32 and/or the operators hand. This powered "navigation element" can aid in the placement of guidewire 50, flexible shaft 12, and/or catheter 14 by reducing the friction between these coaxial elements and themselves and the vasculature. This will facilitate the aspiration catheter system 10 to advance through tortuous geometry, advance through irregular lumens and or stenosed geometry and facilitate advancement of a larger catheter.

[53] The shaft 12 can serve as a "scaffolding element" by enabling the coaxial over-the-shaft advancement of catheter 14 to challenging targets in a manner substantially equivalent to an intermediate catheter. Although the flexible shaft 12 may be too flexible to allow standalone over-the-shaft advancement of catheter 14, the combination of the shaft 12 with an inner guidewire 50 can provide sufficient structure and stiffness for over-the-shaft advancement of the catheter 14. The advancement of the catheter 14 over the shaft 12 can be facilitated by one or a combination of oscillating, rotational, translational, or vibrational motion of the shaft 12, the catheter 14 or a combination of both, powered by the drive system 32 or the hands of the operator. The guidewire 50, the shaft 12 and the catheter 14 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.

[54] After the aspiration catheter 14 is placed in the target, generally in proximity or within the clot mass, in the preferred embodiment the shaft 12 is shielded within the catheter 14, the guidewire 50 at least partially removed from the shaft lumen and the shaft 12 actuated by the drive system 32 as a "thrombectomy element" to generate a hydrodynamic vortex with a steep oblique pressure gradient, as shown in FIG. 16B. In some embodiments, as illustrated in FIGS. 8A-8B, flexible shaft 12 can be composed of multiple segments with different diameters and winding combinations. That is, flexible shaft 12 can comprise a first segment 54 and a second segment 56 (or additional segments). This allows flexible shaft 12 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 12, or unwind, elongating the shaft 12). In some embodiments the windings of shaft 12 are in opposite directions. In some embodiments, flexible shaft 12 comprises a larger diameter wind at the proximal end for torsional strength (in a preferred embodiment for a catheter with ID between 0.060" -0.070", the shaft 12 OD is between 0.026-0.040" with an ID of between 0.016-0.024" and a bending stiffness of approximately between 50 N mm ^A 2 and 5000 N mm ^A 2, where bending stiffness is defined as Young's modulus multiplied by the area moment of inertia of the flexible shaft 12) and a smaller diameter wind at and near the distal tip (typically between 0.026-0.034" OD with an ID of between 0.016-0.024" and a bending stiffness of approximately between 5 N mm ^A 2 and 50 N mm ^A 2) to help navigate through tortuous vessels. This lower bending stiffness distal length preferably extends between 0.5"- 20" from the distal tip 13 of flexible shaft 12. It should be appreciated, as illustrated in FIG. 8C, that multiple shaft 12 segment configuration can be achieved by varying the cross-sectional size of the wire used to construct flexible shaft 12 from a diameter d _p to a diameter d _d , where diameter d _p is larger, smaller, or different than diameter d _d . Moreover, multiple layers of windings can be added to achieve various torsional and bending stiffness (see FIG. 8D). 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 12 in certain sections to reduce the stiffness of that shaft segment.

[55] The outer diameter of flexible shaft 12 is preferably 20-80% of the inner diameter of aspiration catheter 14. Larger shafts 12 tolerate higher torque and bending force during thrombectomy and facilitate atraumatic coaxial advancement of the catheter 14. However, larger shafts 12 tend to cause drop in vacuum power and may not advance easily over a guidewire 50 into the intravascular space during navigation. Smaller shaft 12 may navigate easier and minimize vacuum power loss although may not provide enough structure for coaxial advancement of catheter 14 or resist the torque load needed for vortices generation.

[56] In some embodiments, the same shaft 12 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 12 closest to the drive system 32, the winding of flexible shaft 12 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 12, the winding of flexible shaft 12 and/or diameter of flexible shaft 12 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 12 diameter while optimizing delivery of rotational energy to enable thrombectomy.

[57] In some embodiments, flexible shaft 12 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. [58] The coiling density (coils/length/number and thickness of filars) of flexible shaft 12 can be different within different flexible shafts or along the length of the same shaft. In one embodiment there are between 3 and 12 filars with a thickness between 0.003-0.008". 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.

[59] The cross-sectional design of flexible shaft 12 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 12 (and catheter 14) 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 12 is approximately 0.036" with approximately 8 filar windings while the distal end is approximately 0.032" with 4 filar windings. In other instances, it would be beneficial to increase the diameter of catheter 14 toward the distal end to enhance vacuum efficiency and thrombectomy efficacy.

[60] In some embodiments, the flexibility and torque resistance of flexible shaft 12 can be modified by changing diameter, material, geometric, and braiding features of flexible shaft 12 and/or by introducing a guidewire 50 with different stiffness within flexible shaft 12.

[61] In some embodiments, flexible shaft 12 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 12 preferably includes a hollow channel to enable a guidewire 50 to be coaxially advanced within the flexible shaft 12 for system navigation, while simultaneously achieving sufficient torsional strength to resist breaking during use. [62] In some embodiments, flexible shaft 12 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.

[63] In some embodiments, as illustrated in FIGS. 8A-8B and 9A-9F, flexible shaft 12 comprises one or more hydraulic inducing features 58 that enhance hydraulic forces during rotation of flexible shaft 12. Hydraulic enhancing features 58 can include, but are not limited to, fins, bumps, ridges, and surface micro features, either along the entire shaft of flexible shaft 12, near distal end 13 of flexible shaft 12, or attached to distal end 13 of flexible shaft 12. In some embodiments, hydraulic enhancing features 58 increase hydraulic force to enhance destruction and/or maceration of clot 100.

[64] In some embodiments, as illustrated in FIGS. 8A-8B, 9A-9F, and 10A- 10D, flexible shaft 12 comprises one or more eccentric features 60 to further induce translational motion of flexible shaft 12 to enhance the thrombectomy mechanism. It should be understood that in some embodiments hydraulic enhancing features 58 and eccentric features 60 may be the same feature performing both functions. These eccentric features 60 could be in the form of an eccentrically wound shaft, an eccentric mass fixed to part of flexible shaft 12, an eccentric tip on flexible shaft 12, or a combination thereof. An ideal eccentric feature 60 will be minimal in size so as to not significantly decrease the flexibility of flexible shaft 12 while still being large enough to induce translational motion in flexible shaft 12 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 12, and may even extend beyond the distal most end of flexible shaft 12.

[65] In another embodiment, an off-center channel at least partially along the shaft 12 or the shaft tip 64 would create eccentric features.

[66] Flexible shaft 12 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 12 and clot 100. This would translate into stronger hydrodynamic waves and grasp of clot 100 by flexible shaft 12 resulting in enhanced corkscrew inward traction of clot 100 into catheter 14. [67] Flexible shaft 12 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 12, the guidewire 50 and the catheter 14.

[68] Flexible shaft 12 can be advanced or withdrawn to optimize its position into the maximal thrombectomy zone 74 to optimize the interaction between shaft and clot 100 in the engagement zone. In addition, it can be completely withdrawn from catheter 14 and exchanged if needed.

[69] The advancement or retraction of flexible shaft 12, guidewire 50, and/or catheter 14 can be enhanced by very low speed rotation (typically <200 rpm), vibration or oscillation (typically greater than 2 Hz) of flexible shaft 12 by the user's hand or a drive system 32. It should be noted that this operation mode is for device navigation. For thrombectomy, the preferred embodiment is with flexible shaft 12 fully contained within catheter 14 and rotated at higher speeds as set forth herein.

[70] In some embodiments, flexible shaft 12 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 14 can be enhanced by very low speed rotation (typically <200 rpm), vibration, or oscillation (typically greater than 2 Hz) of catheter 14 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.

[71] In some embodiments, as illustrated in FIGS. 8A-8B and 1 1A-1 1 F, flexible shaft 12 comprises a shaft tip 64 that is connectable, coupled, or otherwise extending from distal end 13 of flexible shaft 12. In some embodiments, shaft tip 64 can be rounded and have smooth atraumatic edges 66 during navigation in the vessel, and have one or more sharp edges 68 during thrombectomy mode. This can be achieved by, but not exclusively by: 1 ) including grooves in an angled position, resulting in two edges, one sharp and the other dull (see FIGS. 1 1A-1 1 C). When flexible shaft 12 rotates clockwise, the sharp edge moves forward to engage and cut clot 100 (active thrombectomy mode). When flexible shaft 12 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 64 can be otherwise rounded or smooth to facilitate advancement with the introduction of the guidewire 50 for navigation mode. In some embodiments, shaft tip 64 includes a lumen in the tip that is co-axially oriented to the main longitudinal axis of flexible shaft 12 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 50 for navigation mode, and a "spoon" notch in flexible shaft 12 tip for clot 100 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 12 and vortex generation upon rotation at high speed. As the outer diameter of guidewire 50 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 12.

CATHETER

[72] In some embodiments, catheter 14 is configured to be navigated through vascular geometries, and is made from pliable material. In some embodiments, catheter 14 is made sufficiently stiff to not collapse under suction force or kink upon small bending radius. In some embodiments, catheter 14 is structurally reinforced to prevent kinking of the lumen with bending.

[73] In some embodiments, wall surface 17 of catheter 14 has a hollow channel that spans the length of catheter 14 and opens distally. This hollow channel enables a guidewire 50 to be disposed within the wall of catheter 14 (FIG. 7D). This guidewire 50 can optionally be steerable and be advanced outside the distal end of catheter 14 into the vascular lumen to facilitate and direct advancement of catheter 14 into the mass of clot 100 and into the target vessel, both before, during, or after mechanical thrombectomy by powering flexible shaft 12 in catheter 14 as described herein.

[74] In some embodiments, as illustrated in FIG. 12, the combination of flexible shaft 12 and catheter 14 can define one or more zones that are particularly adapted and configured to perform mechanical thrombectomy upon clot 100. As disclosed herein, flexible shaft 12 is positioned within catheter 14 and is rotating at a very high speed to create hydrodynamic vortices and corkscrew movements to further disrupt clot 100. Generally, a clot engager zone 70 is located from distal end 15 of catheter 14 and proximally extends within catheter 14 to a location 72 proximal from distal end 13 of flexible shaft 12. A maximal thrombectomy zone 74 is further proximally located relative to clot engager zone 70, although maximal thrombectomy zone 74 can overlap clot engager zone 70 to some, all or no extent. Maximal thrombectomy zone 74 can be bound at a distal end 76 (extending distally past distal end 13 of flexible shaft 12) and a proximal end 78 (extending proximally relative to distal end 13 of flexible shaft 12). An anti-clog zone 80 is still further proximally located relative to maximal thrombectomy zone 74 and generally extends within catheter 14.

[75] In some embodiments, the distal most segment (e.g. clot engager zone 70) of catheter 14 may be at an angle to the longitudinal axis of catheter 14.

[76] Clot engager zone 70 anchors clot 100 to catheter 14 optimizing the thrombectomy mechanisms described herein. In addition, clot engager zone 70 maintains clot 100 anchored to catheter 14, 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 12 and contacting clot 100, and vacuum overlapping at clot engager zone 70 provides a synergetic thrombectomy milieu that is safely contained within catheter 14. In addition, clot engager zone 70 provides a safety buffer zone to allow the periodic elongation and contraction of flexible shaft 12 when it is rotated at high speed, such that flexible shaft 12 is not disposed on the outside of catheter 14 where it can potentially cause damage to the blood vessels or body cavity.

[77] In some embodiments, at least the maximal thrombectomy zone 74 of catheter 14 will have a reinforced segment 82 to increase the structural resistance of catheter 14 to forces and energy transmitted by the motion of flexible shaft 12, as shown in FIG. 12. This segment 82 can be coated with anti-abrasive material. In some embodiments, distal end 15 of catheter 14 and maximal thrombectomy zone 74 can be structurally reinforced to prevent collapse of the lumen of catheter 14 with vacuum.

[78] In some embodiments, at least the maximal thrombectomy zone 74 of catheter 14 comprises fluoroscopic markers to aid in the positioning of distal end 13 of flexible shaft 12 in optimal position for activation.

[79] In some embodiments, fluoroscopic markers, CT and MRI markers can be provided in any portion of catheter 14, guidewire 50, and/or flexible shaft 12.

[80] In some embodiments, distal end 15 of catheter 14 includes one or more uneven features 84 disposed thereon (e.g. rounded bumps). In some embodiments, features 84 can be along the same direction as the long axis of catheter 14. Features 84 help to penetrate and break apart clot 100 due to concentrated areas of high shearing force as clot 100 is dragged inward into maximal thrombectomy zone 74 following a corkscrew path.

[81] In some embodiments, as illustrated in FIGS. 8B and 13A-13C, catheter 14 may have accessory lumen, channel, or holes 86 in the wall to allow fluid (saline solution, blood, medication, etc.) to fill the lumen of catheter 14 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 FIGS. 7D, 8B, and 13A-13C, catheter 14 may have accessory lumen or channel 88 throughout the totality or part of its extension to allow guidewire 50 or other wire to be disposed within for navigation or to infuse solutions or medications. Particularly, as illustrated in FIG. 13A, a channel 88 can be disposed within the sidewall of catheter 14 to deliver a fluid. As illustrated in FIG. 13C, channel 88 can extend along an ancillary channel of catheter 14. In some embodiments, the fluid can be delivered through the hollow interior of flexible shaft 12 (FIG. 13B).

[82] In some embodiments, wall surface 17 of catheter 14 has a hollow channel that spans at least part of the length of catheter 14 and opens at the distal end of catheter 14, into the lumen of catheter 14, or a combination thereof. This hollow channel enables the advancement of a guidewire 50 to be used in monorail system, both during navigation mode of catheter 14 (with or without co-axial advancement over a shaft) and thrombectomy mode. In the latter option, flexible shaft 12 is rotating at very high speed inside catheter 14 causing clot 100 engagement and fragmentation while catheter 14 is advanced or pulled back over the monorail wire disposed in the vascular lumen, and not in contact with flexible shaft 12 (Fig 8).

[83] In some embodiments, wall surface 17 of catheter 14 has a hollow channel that spans at least part of the length of catheter 14 and opens at the distal end of catheter 14, into the lumen of catheter 14, 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 100 mass and: 1 ) be pulled back facilitating entrance of clot 100 into catheter 14; 2) remain distal to clot 100 to capture embolization particles and then be pulled back allowing these particles to be removed by catheter 14.

[84] In some embodiments, wall surface 17 of catheter 14 has a hollow channel that spans at least part of the length of catheter 14 and opens at the distal end of catheter 14, into the lumen of catheter 14, or a combination thereof. This hollow channel enables the advancement of an occlusive device, such asas a balloon, which can be advanced through clot 100 mass and then: 1 ) insufflated to prevent distal embolization by stopping anterograde flow, 2) be pulled back facilitating entrance of clot 100 into catheter 14.

[85] In some embodiments, wall surface 17 of catheter 14 or flexible shaft 12 can have a hollow channel to deliver medication, cooling fluids or other agents toward the distal end of catheter 14.

[86] In some embodiments, catheter 14 may have a flow occlusion mechanism, such as one or more balloons, near or at the distal end 15 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.

[87] In some embodiments, catheter 14 includes a filter device for capturing undesirable material and removing it from the fluid flow.

THROMBECTOMY FORCES

[88] The rotation of flexible shaft 12 contained within catheter 14 induces key engagement and fragmentation mechanisms (see FIGS. 14A-14B, 15A-15D, 16A- 16B, 19A-19G), such as, but not limited to:

a. Hydraulic forces created between flexible shaft 12 and the inner wall surface 17 of catheter 14 due to the rotation of flexible shaft 12 within catheter 14 and the induced uncoupled translational motion of flexible shaft 12 (see FIGS. 14A-14B) that fragments clot 100 within catheter 14. b. The hydraulic forces created by high speed shaft rotation and orbiting coupled with vacuum generate a vortex with a steep pressure gradient obliquely oriented in the lumen of catheter 14 and rotating inside catheter 14 (see FIGS. 16A-16B).

c. This vortex generates a torsional indraft pull following an inward corkscrew pathway to further engage clot 100 into catheter 14 and create shear stress that is more effective than stand-alone vacuum to anchor, pull, and fragment clot 100 (see FIGS. 19A-19G). d. The vortex also potentiates clot 100 engagement, fragmentation, and inward movement of the clot 100 proximally within catheter 14 due to the transformation of static friction between clot 100 and inner wall 17 to kinetic friction which tends to produce a lower resistive force between clot 100 and inner wall 17.

e. The high frequency excitation of flexible shaft 12 fragments clot 100 further and causes flexible shaft 12 to repeatedly hit the inner surface of catheter 14 (see FIGS. 15A-15D)). This creates a high frequency

(typically 100 to 300 Hz), low amplitude vibration (typically 50pm to 200pm) of catheter 14 that aids in clot 100 disruption, indicated as the "vibration" in FIG. 14A.

f. The high-speed rotation of flexible shaft 12 in combination with the coiled wire design of flexible shaft 12 induces a periodic elongation and contraction of flexible shaft 12 due to torsional vibration and unstable turbulent flow, indicated as the "elongating and contracting" in FIG. 14B. This dynamic forward and backward movement of a distal end 13 of flexible shaft 12 lengthens the zone 74 of maximal thrombectomy efficacy. By way of non-limiting example, periodic elongation and contraction can be within about 0.1 to 5 mm, based on shaft material, winding pattern, wire diameter, torsional modulus, vessel tortuosity, and the like.

g. The hydrodynamic forces generated by high speed rotation of flexible shaft 12 induces 3-dimensional corkscrew movement of flexible shaft 12, which swipes between inner wall surface 17 of catheter 14 and clot 100 surface. This minimizes static friction between clot 100 and wall surface 17 of catheter 14, de-attaching clot 100 from wall surface 17 of catheter 14, and enhancing clot 100 removal by transforming static friction to kinematic friction. It should be understood that the three-dimensional corkscrew configuration and movement of flexible shaft 12 is achieved upon application of high-speed rotational motion (typically greater than 10,000 RPM).

h. At rest, the flexible shaft 12 substantially defines a straight, linear profile, without the need for complex preformed shapes, such as angles, J's, sinusoids, and the like. In some embodiments, non-linear shapes of flexible shaft 12 at rest can be used in connection with the present teachings. These shapes can be fixed or acquired after removal of inner guidewire 50. i. Static friction is substantially reduced or eliminated by the steep pressure gradient obliquely oriented in catheter 14 that rotates inside catheter 14 and extends throughout the lumen of catheter 14.

j. The movement of flexible shaft 12 also engages with clot 100 substance enhancing/accelerating the inward corkscrew path to further engage and fragment clot 100.

k. The same mechanisms described herein can occur from the distal end of the maximal thrombectomy zone 74 to the proximal end of catheter 14 with decreased intensity preventing the lumen from clogging, indicated as the anti-clog zone 80 in FIG. 12A.

I. Features on flexible shaft 12, such as but not limited to an angled eccentric mass 58, 60 on distal end 13, can further act to pull clot 100 into catheter 14 by transmitting axial and tangential forces to clot 100.

[89] In some embodiments, to enhance the axial force of the rotating shaft 12, magnets can be added the catheter 14 and flexible shaft 12 such that when flexible shaft 12 is rotated with respect to catheter 14, the poles of the opposing magnets periodically attract and repel one another.

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

[91] In some embodiments, to enhance the hydrodynamic force on the rotating shaft 12, hydrophilic coatings can be applied to shaft 12.

METHOD

[92] With reference to FIGS. 17A-17G, in some embodiments during clot maceration and removal, guidewire 50 is advanced within the lumen of the vessel/cavity/space to clot 100 (FIG. 17A). Distal end 13 of flexible shaft 12 is then advanced along guidewire 50 and placed in proximity or within the mass of clot 100 (FIG. 17B). The longitudinal displacement of the shaft 12 can be facilitated by low speed rotation, oscillation or vibration by the dive system 32. Distal end 15 of catheter 14 is then navigated into the target vessel/cavity/space and placed in proximity or within the mass of clot 100 (FIG. 17C). During this navigation and positioning, it can also be advantageous to retract shaft 12 in cooperation with the advancement of catheter 14. This can be achieved through manual or automatic retraction actuation of shaft advancement slider 28 in cooperation with manual or automatic advancement of catheter 14 by means of vacuum port assembly 18 and/or aspiration catheter system 10. In some embodiments, catheter 14 can be further supported internally and/or externally using additional supporting elements such as a guiding catheter, an introducer, or combinations thereof. Guidewire 50 can be retracted or fully removed from the vessel or aspiration catheter system 10. Flexible shaft 12 is positioned in catheter 14 to reach maximal thrombectomy zone 74 (FIG. 17D). Suction from vacuum source 24 begins and draws clot 100 portion into clot engager zone 70 of catheter 14 either prior, concurrent and/or after the flexible shaft 12 is rotated at high speed in accordance with the principles of the present teachings. Thrombectomy is fully contained within catheter 14 as described herein. Catheter 14 and clot 100 remain engaged during the thrombectomy stage (FIGS. 17E-17G and 19A-19G). Suction continues and clot 100 enters further into maximal thrombectomy zone 74 of catheter 14. Flexible shaft 12 is further rotated inside catheter 14 at high speed generating thrombectomy by the mechanisms described herein. However, as needed during the thrombectomy procedure, the rotation of flexible shaft 12 can be momentarily stopped and once again become the navigation and scaffolding element if needed. The fragmented clot 100 inside catheter 14 is continuously aspirated away from the vascular lumen and undergoes further fragmentation along the total length of catheter 14 by the mechanisms described herein.

[93] In some embodiments, fragmentation and/or maceration of clot 100 are only active in maximal thrombectomy zone 74 (FIGS. 17E-17G). Simultaneously, un- fragmented clot 100 is dragged inwards into clot engager zone 70 and then further into maximal thrombectomy zone 74 for further thrombectomy as described herein.

[94] In some embodiments, the action of thrombectomy and maceration in FIGS. 17E-17G results in catheter 14 advancing into the substance of clot 100 and distally into the target vessels until complete removal of clot 100 is achieved (FIG. 17G).

[95] In some embodiments, as illustrated in FIGS. 18A-18D, a secondary wire 99 can be used to guide catheter 14 and flexible shaft 12 during thrombectomy. The secondary wire 99 can be located in channel 52 of catheter 14 or along a channel thereof.

[96] In some embodiments, flexible shaft 12 can be actuated at or near the proximal end of flexible shaft 12 to induce translational motion at least at the distal end of catheter 14. This can be used both exclusively and in conjunction with the rotational motion to increase thrombectomy capability.

[97] In some embodiments, shaft 12 can be rotated at high speed outside (e.g. beyond) distal end 15 of catheter 14 following orbital movements that extend along a path that could be larger than the diameter of catheter 14. The diameter of this orbital movement of shaft 12 outside catheter 14 is dependent upon the rotational speed, the length of shaft 12 protruding outside catheter 14, the ID of catheter 14, and the flexibility of shaft 12. The translational movement of a shaft 12 with enough stiffness to act as cutting tool will generate a cutting cone to fragment tissues and clots 100. 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 14 distal-most opening) to induce bipolar current and simultaneous coagulation during tissue maceration. This can also be coupled to hollow channel 52 along the wall of catheter 14 that enables a fluid media to be delivered at or near the distal end of catheter 14 which can then backfill catheter 14 lumen by vacuum. This would enable the generation of hydraulic forces and translational shaft motions when catheter 14 is not already immersed into a liquid environment.

[98] 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 50 or the secondary wire 99 is advanced to the clot 100 and the flexible shaft 12 is advanced to the clot. In some embodiments, the flexible shaft 12 is advanced over the guidewire 50. The catheter 14 is then advanced over the flexible shaft 12 and/or guidewire 50 to the clot 100. The guidewire 50 can then be removed partially or totally. The catheter 14 and/or flexible shaft 12 is then positioned such that the flexible shaft 12 is fully contained within the catheter 14. 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 99 is used, the catheter is moved longitudinally over the secondary wire 99 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. [99] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.