Cyclic aspiration system having a non-powered internal structural obstruction that engages the clot to assist capture

Abstract

A cyclic aspiration system including a suction catheter and a cyclic aspiration source fluidly connected thereto, the cyclic aspiration pressure source generating a cyclic aspiration pressure waveform with intermittent cycles of a vacuum pressure below atmospheric pressure and a positive pressure higher than the vacuum pressure. The system further includes a non-powered internal structural obstacle disposed within the lumen of the suction catheter and configured to engage a captureable clot therein and during resulting movement between the clot and the non-powered internal structural obstacle while subjected to the cyclic aspiration pressure waveform to assist in capturing the clot. The non-powered internal structural obstacle may be permanently attached to the suction catheter or a separate component or device independently slidable within the lumen of the suction catheter.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 447,506, filed February 22, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0002] FIELD OF THE INVENTION The present disclosure generally relates to an aspiration system for use during a thrombectomy procedure to capture and remove a targeted clot. Preferably, the present disclosure relates to a cyclic aspiration system that assists or assists in capturing a clot, particularly a fibrin-rich clot and / or a clot that is too large in size to be accommodated by a conventional aspiration catheter, by engaging the clot with a non-powered internal structural obstacle. [Background technology]

[0003] During endovascular procedures, the target clot is often a fibrin-rich clot in which densely packed fibrin threads have become entangled with platelets, forming a hardened mass that prevents capture into the catheter by aspiration. Another factor that affects the success of capturing a clot into a catheter by aspiration is when the overall size of the clot is too large to be accommodated within the aspiration catheter. These characteristics pose significant challenges to the effective capture and removal of the target clot via the aspiration catheter. Therefore, it would be desirable to develop an improved cyclic aspiration system that addresses these concerns by including an internal structural obstacle configured to engage and assist in the capture of the clot. Summary of the Invention [Means for solving the problem]

[0004] One aspect of the present disclosure is directed to an improved cyclic aspiration system, particularly for use in capturing fibrin-rich clots or clots whose overall size is too large to be contained within an aspiration catheter.

[0005] A further aspect of the present disclosure is directed to an improved cyclic aspiration system that is more efficient at capturing / entrapping and removing blood clots within the aspiration catheter by physically changing its state during entrapment.

[0006] However, yet a further aspect of the present disclosure relates to an improved cyclic aspiration system that includes a non-powered internal structural obstruction disposed within the lumen of the aspiration catheter, which engages with the clot and assists in its capture by utilizing kinetic energy during cyclic aspiration, such that the internal structural obstruction does not require its own power source (i.e., is non-powered). By simplifying and minimizing the number of components of the non-powered internal structural obstruction in this manner, the bulk, footprint, weight, and cost of the cyclic aspiration system according to the present disclosure are minimized. [Brief explanation of the drawings]

[0007] The above and further aspects of the present disclosure are further discussed with reference to the following description in conjunction with the accompanying drawings, in which like numerals refer to like structural elements and features in the various views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the present disclosure. The figures depict one or more implementations of the device by way of example only, and not by way of limitation. [Figure 1A] FIG. 1 is a perspective view of a distal section of an exemplary aspiration catheter having a single taut wire traversing at least a portion of its lumen to act as a non-powered internal structural obstruction in accordance with the present disclosure. [Figure 1B] FIG. 1B is a distal end view of the aspiration catheter of FIG. 1A. [Figure 1C] FIG. 1B is a perspective view of the distal section of the exemplary modified aspiration catheter of FIG. 1A having a single taut wire traversing at least a portion of its lumen acting as a non-powered internal structural obstruction, the taut wire being affixed to the proximal braided section and extending distally thereof to form a distal coil section, in accordance with the present disclosure. [Figure 1D] FIG. 1D is a side view of the aspiration catheter of FIG. 1C. [Figure 1E] FIG. 10 is a side view of a distal section of yet another exemplary aspiration catheter having a single loose (i.e., untensioned) wire traversing at least a portion of the lumen acting as a non-powered internal structural obstruction in accordance with the present disclosure. [Figure 1F] FIG. 1D is a side view of the aspiration catheter of FIG. 1E, with the aspiration catheter and proximal braided section cut away to show a single loose wire traversing at least a portion of the lumen and forming the distal coil section. [Figure 1G] FIG. 12 is a perspective view of the distal section of yet another exemplary aspiration catheter according to the present disclosure having a single rib (i.e., flat or straight) acting as a non-powered internal structural obstacle, the single rib traversing the lumen with each end of the rib secured to a marker band section. [Figure 1H] FIG. 1G is a bottom perspective view of the aspiration catheter of FIG. 1G, showing a single rib from another angle. [Figure 2] FIG. 10 is a perspective distal cross-sectional view of yet another exemplary aspiration catheter having four radial ribs acting as non-powered internal structural obstacles in accordance with the present disclosure. [Figure 3A] FIG. 10 is a distal end view of yet another exemplary aspiration catheter including a ring of helical teeth arranged 360 degrees to act as a non-powered internal structural obstruction in accordance with the present disclosure. [Figure 3B] FIG. 10 is a distal end view of yet another exemplary aspiration catheter including a ring of helical braids arranged 360 degrees to act as a non-powered internal structural obstruction in accordance with the present disclosure. [Figure 3C] FIG. 3C is an axial cross-sectional cutaway view of the distal section of the exemplary aspiration catheter of FIG. 3B, showing only two of the spiral braids to illustrate the shape and placement of the individual braids along the inner wall of the distal section of the aspiration catheter. [Figure 4A] FIG. 10 is an axial cross-sectional view of a distal section of yet another exemplary aspiration catheter including a deflectable, proximally facing inner ring of serrations that acts as a non-powered internal structural obstruction in accordance with the present disclosure. [Figure 4B]FIG. 4B is a perspective view of the distal section of the aspiration catheter of FIG. 4A. [Figure 4C] FIG. 10 is an axial cross-sectional view showing the deflection of two saw teeth in the proximal direction. [Figure 5A] FIG. 10 is an axial cross-sectional view of a distal section of yet another example aspiration catheter including multiple rings of teeth arranged axially one after the other to act as a non-powered internal structural obstruction in accordance with the present disclosure. [Figure 5B] FIG. 5B is a distal end view of the aspiration catheter of FIG. 5A. [Figure 6A] FIG. 10 is a side view of the distal section of yet another exemplary aspiration catheter including an axially compressible spring section that acts as an auxiliary non-powered internal structural obstruction that generates an auxiliary vibration effect, which, when combined with any other example of a distally positioned non-powered internal structural obstruction disclosed herein, generates a primary vibration effect while assisting in clot tearing in conjunction with cyclic aspiration, the axially compressible spring section shown in an axially expanded state. [Figure 6B] FIG. 6C is a side view of the distal section of the aspiration catheter of FIG. 6B, with the axially compressible spring section shown in an axially compressed state. [Figure 7A] FIG. 10 is an axial cross-sectional view of a distal section of yet another exemplary aspiration catheter according to the present disclosure, the distal section having an inner wall section with an inner profile of tapered ribs that act as a non-powered internal structural obstacle. [Figure 7B] FIG. 7B is an axial cross-sectional view of the aspiration catheter of FIG. 7A showing the clot engaging the inner contour of the tapered rib tearing off pieces of its outer contour during the vacuum pressure intervals of the cyclic aspiration. [Figure 8A] FIG. 10 is an axial cross-sectional view of a distal section of yet another exemplary aspiration catheter according to the present disclosure, including two sets of flaps arranged axially one behind the other to act as non-powered internal structural obstructions. [Figure 8B] FIG. 8B is an axial cross-sectional view of the aspiration catheter of FIG. 8A while subjected to blood flow or vacuum pressure during cyclic aspiration, with the flap in an open state allowing blood to pass through. [Figure 8C] FIG. 8B is an axial cross-sectional view of the aspiration catheter of FIG. 8A while undergoing positive pressure intervals during cyclic aspiration, with the flap in a closed state preventing distal retrograde blood flow. [Figure 8D] 8B is an axial cross-sectional view of the distal section of the aspiration catheter of FIG. 8A shown advanced proximally to the target clot and with the flap shown in an open position prior to application of cyclic suction. [Figure 8E] FIG. 8B is an axial cross-sectional view of the distal section of the aspiration catheter of FIG. 8A shown undergoing vacuum pressure intervals during periodic aspiration, showing the flaps expanding to accommodate the clot as it is drawn into the aspiration catheter. [Figure 8F] FIG. 8B is an axial cross-sectional view of the distal section of the aspiration catheter of FIG. 8A , shown undergoing positive pressure intervals between periodic aspirations that transition the flaps to a closed state to clamp / hold / restrain the entrapped clot and prevent its expulsion from the aspiration catheter while also assisting in clot tearing. [Figure 9A] FIG. 10 is a perspective view of a distal section of yet another exemplary aspiration catheter including a multi-segment fiber acting as a non-powered internal structural obstruction according to the present disclosure, the multi-segment fiber having sufficient slack to be displaceable and reconfigurable while remaining anchored within the lumen of the aspiration catheter. [Figure 9B] FIG. 9B is a side view of the distal section of the aspiration catheter of FIG. 9A. [Figure 9C] 9B illustrates the distal end of the aspiration catheter of FIG. 9A, where the multi-segment fiber has been displaced in a number of exemplary configurations to accommodate passage of an auxiliary device without interfering with the multi-segment fiber. [Figure 9D] 9B illustrates the distal end of the aspiration catheter of FIG. 9A, where the multi-segment fiber has been displaced in a number of exemplary configurations to accommodate passage of an auxiliary device without interfering with the multi-segment fiber. [Figure 9E]9B illustrates the distal end of the aspiration catheter of FIG. 9A, where the multi-segment fiber has been displaced in a number of exemplary configurations to accommodate passage of an auxiliary device without interfering with the multi-segment fiber. [Figure 10A] FIG. 10 is a cutaway axial view of a distal section of an exemplary discrete, non-powered internal structural obstruction according to the present disclosure that is slidable within the lumen of an aspiration catheter. [Figure 10B] 10B is a cutaway perspective view of a suction catheter having a separate internal structural obstruction within the lumen of FIG. 10A. [Figure 10C] FIG. 10B is a distal end view of the internal structural obstruction of FIG. 10A. [Figure 10D] FIG. 10B is an exploded view of the aspiration catheter and non-powered internal structural obstruction of FIG. 10A. [Figure 11A] FIG. 10 is a side view of another example of a separate, non-powered internal structural obstruction as a single preformed wire slidable through the lumen of an aspiration catheter according to the present disclosure. [Figure 11B] FIG. 11B is a cutaway axial view of an aspiration catheter having a single preformed wire of FIG. 11A advanced through its lumen. [Figure 11C] FIG. 11B is a cutaway axial view of the aspiration catheter with the single preformed wire of FIG. 11A advanced through its lumen, shown during vacuum pressure intervals of cyclic aspiration drawing clot into the distal tip / end of the aspiration catheter. [Figure 11D] FIG. 11B is a cutaway axial view of the aspiration catheter of FIG. 11A with a single preformed wire advanced through its lumen, shown during a positive pressure interval of cyclic aspiration, showing the clot pierced by the teeth of the single preformed wire. [Figure 11E] FIG. 10 is a side view of another example of a four preformed wire discrete non-powered internal structural obstruction according to the present disclosure. [Figure 11F] FIG. 11F is a bottom perspective view of the four preformed wires of FIG. 11E. [Figure 11G] FIG. 10 is a side view of yet another example of a separate, non-powered internal structural obstruction as a single wire having a reinforcing loop disposed at its distal end to maintain proper positioning of the teeth. [Figure 12]An exemplary aspiration catheter system including a pulsatile vacuum pump fluidly connected to an aspiration catheter that is delivered to a target site prior to capturing / entrapping a blood clot therein, and any of the exemplary non-powered internal structural obstructions shown above may be disposed within the lumen of the aspiration catheter. DETAILED DESCRIPTION OF THE INVENTION

[0008] As used herein, the term "about" or "approximately" in connection with any numerical value or numerical range indicates a suitable dimensional tolerance that enables a portion of a component or a collection of components to function for its intended purpose as described herein. More specifically, "about" or "approximately" may refer to a range of values ​​of ±20% of the recited value; for example, "about 90%" may refer to a range of values ​​of 71% to 99%.

[0009] As used herein, the terms "tubular" and "tube" are intended to be broadly construed and are not limited to right cylindrical structures, or structures that are strictly circular in cross section, or structures that are uniform in cross section throughout their length. For example, a tubular structure or tubular system is generally depicted as a substantially right cylindrical structure. However, a tubular system can have a tapered or curved outer surface without departing from the scope of the present disclosure.

[0010] The documents incorporated by reference into this patent application should be considered an integral part of this application, provided that to the extent that any term is defined in these incorporated documents in a manner that contradicts the definition given herein, either expressly or implicitly, only the definition given herein should be considered.

[0011] Conventional aspiration catheters are prone to clogging when used to capture fibrin-rich clots and / or oversized clots that exceed the overall size of the aspiration catheter. Therefore, it would be desirable to develop an improved aspiration catheter that has a non-powered (i.e., does not require its own energy or power source, e.g., a battery or other power supply) internal structural obstacle to disrupt, cut, tear, restrain, and / or change shape of the clot, thereby improving the efficiency of internal capture / entrapment and removal. Rather than having to power the internal structural obstacle, kinetic energy imparted during application of cyclic or pulsatile suction is instead utilized to effect movement between the clot and the non-powered internal structural obstacle (e.g., movement of the clot while the internal structural obstacle remains stationary, or movement of the internal structural obstacle while the clot remains stationary).

[0012] Systems and methods according to the present disclosure are directed to an improved cyclic suction system for capturing and removing blood clots. An exemplary cyclic suction system is shown in FIG. 12 , including a cyclic suction source (e.g., a pulsatile vacuum pump) 1200 connected to a proximal hub 1207 at the proximal end of an aspiration catheter 1205. The aspiration catheter 1205 has an internal structural obstacle disposed in a distal section of a lumen proximal to the distal tip / end according to any one of the examples shown herein and described in detail below. The cyclic suction source generates a cyclic suction pressure waveform with intermittent, periodic intervals of vacuum pressure below atmospheric pressure and positive pressure above vacuum pressure, and in some cases above atmospheric pressure. FIG. 12 shows the aspiration catheter being delivered through a blood vessel to a target site for a blood clot before applying cyclic suction. Kinetic energy while undergoing cyclic suction is harnessed to effect engagement between the clot and the non-powered internal structural obstacle. According to the present disclosure, engagement of a clot with a non-powered internal structural obstacle results in (i) disrupting the structure of the clot from a single, monolithic structure that is fragmented, divided, cut, or torn into two or more clot fragments; (ii) changing the shape of at least a portion of the clot (e.g., reconfiguring, reshaping, and / or elongating); and / or (iii) restricting distal migration of a clot that may be captured therein. In some examples, the non-powered internal structural obstacle can retain, grasp, clamp, or hold a portion of the captured clot within the aspiration catheter, restricting distal migration of the clot while minimizing the risk of expulsion of the clot from the distal end. In some examples, during positive pressure intervals of cyclic aspiration, the non-powered internal structural obstacle can change the shape of the clot (e.g., elongate), thereby improving capture / entrapment. Engagement of a clot with a non-powered internal structural obstacle according to the present disclosure improves the efficiency of capture / entrapment while minimizing the risk of the clot becoming lodged within the aspiration catheter.

[0013] While non-limiting examples of non-powered internal structural obstruction members according to the present disclosure are illustrated and described herein, other examples are contemplated. In some examples, the non-powered internal structural obstruction is permanently fixed in place within the lumen of the aspiration catheter itself, while in other examples, the non-powered internal structural obstruction is a separate component or device that is independently slidable within the lumen of the aspiration catheter.

[0014] The first described example is that of a non-powered internal structural obstruction permanently secured in place within the lumen of the aspiration catheter itself. In FIGS. 1A and 1B, the cyclic aspiration system includes a suction catheter 105. As shown in the perspective view of the distal section of the aspiration catheter 105 having a distal end 115 in FIG. 1A, a braided proximal section 130 and a distally disposed marker band section 135 having an opening 145 are secured within the lumen of the aspiration catheter 105. In the example of FIGS. 1A and 1B, the internal structural obstruction is a taut wire 150 that extends through or traverses at least a portion of the lumen of the aspiration catheter 105. While the distal end view of FIG. 1B shows an exemplary wire 150 traversing the entire diameter of the opening 145 (i.e., substantially the entire diameter of the lumen of the aspiration catheter 105), the wire 150 may alternatively traverse only a segment or portion of the opening 145 (i.e., only a portion of the lumen of the aspiration catheter 105). 1A , wire 150 is integral with braid proximal section 130, extends therefrom, passes through a first opening (e.g., hole) 140 defined in marker band section 135, traverses at least a section of opening 145 in marker band section 135, passes through a second opening (e.g., hole) 140 defined in marker band section 135, and has its opposite end secured thereto (e.g., glued, welded, or otherwise permanently affixed). In an alternative configuration, wire 150 is integral with braid proximal section 130, extends from braid proximal section 130 across at least a portion of opening 145, and then wire 150 may be formed into a coil distal section 135′ disposed distally of braid proximal section 130 ( FIGS. 1C and 1D ). If wire 150 is made of a radiopaque material (e.g., tungsten), coil distal section 135' can simultaneously serve as a marker band section. Alternative methods can be used to secure (e.g., glue or weld) each end of wire 150.The use of a single wire 150 as an internal structural obstacle advantageously leaves sufficient free space for auxiliary device(s) (e.g., guidewire, microcatheter, etc.) to advance through the lumen of the aspiration catheter without interfering with the wire 150.

[0015] The selection of the axial position of wire 150 relative to the distal tip / end of aspiration catheter 105 affects the size of the fragments into which the clot is disrupted, divided, cut, or torn during engagement resulting from back-and-forth (i.e., bidirectional) relative movement between the clot and wire 150 while subjected to cyclic aspiration. That is, placing wire 150 more proximally (i.e., farther from the distal tip / end 115 of aspiration catheter 105) will disrupt, divide, cut, or tear the clot into larger-sized fragments, while placing wire 150 more distally (i.e., closer toward the distal tip / end 115 of aspiration catheter 105) will disrupt, divide, cut, or tear the clot into smaller-sized fragments. In the example shown in FIGS. 1A-1D , the internal structural obstruction is a single wire 150, although two or more wires are contemplated and within the scope of the present disclosure. Multiple wires may be positioned at different positions along the axial / longitudinal length of the suction catheter 105, and / or multiple wires may be used at the same axial / longitudinal position within the suction catheter 105 (i.e., in the same radial plane), but extend along different paths across at least a portion of the lumen of the suction catheter 105.

[0016] Although the single wire 150 in FIGS. 1A-1D is secured in tension as it traverses at least a portion of the opening 145 (i.e., at least a portion of the lumen of the aspiration catheter 105), the wire may otherwise be looser (i.e., not in tension), more like a string, as shown in FIGS. 1E and 1F. By way of example, the loose wire 150 in FIGS. 1E and 1F has a single slack section (e.g., U-shaped), although the number of separate slack sections of the wire and their shapes can be selected as desired. After traversing the lumen, the loose wire 150 forms the coiled distal section 135′ of the inner sleeve 125 distal to the braided proximal section 130. The one or more slack sections of the wire 150 advantageously allow some movement or displacement out of the way, allowing for the passage of other auxiliary device(s) (e.g., guidewires, microcatheters, etc.) through the aspiration catheter without interference. Additionally, the one or more slack sections of wire 150 themselves may move when subjected to periodic suction, thereby further facilitating the disruption, division, or tearing of the clot into multiple pieces.

[0017] 9A-9E illustrate yet another example of an aspiration catheter 905 according to the present disclosure, in which the internal structural obstruction is a multi-segment fiber (e.g., a three-segment fiber) 950. Each segment of the fiber is anchored at a first end to the inner wall of the aspiration catheter 905, and the opposing second ends are anchored to each other within the lumen of the aspiration catheter 905, allowing for deliberate reconfiguration or displacement of the multi-segment fiber 950. In the illustrated example, the first end, at which all three segments of the fiber are anchored to each other, lies in a first radial plane disposed proximally relative to the opposing second ends, which are permanently attached to the inner wall of the aspiration catheter 905 in the second radial plane (see side view in FIG. 9B). 9C-9E illustrate several illustrative examples of different reconfigurations of the multi-segment fiber 950 to allow for the passage of auxiliary device(s) (e.g., a guidewire, a microcatheter, etc.) through the lumen of the aspiration catheter 905 without interfering with the three-segment fiber 950. Preferably, the fibers 950 are made of a material selected to minimize profile and maximize strength sufficient to disrupt, split, cut, or tear the clot into multiple pieces while engaging the clot during relative movement between the clot and the non-powered internal structural obstacle during aspiration.

[0018] As an alternative to the single, multiple, or multi-segment wires or fibers described above, the non-powered internal structural obstruction traversing at least a portion of the opening 145 (i.e., at least a portion of the lumen of the aspiration catheter) may be a straight or linear rib (e.g., a blade) 150′. FIGS. 1G and 1H show an exemplary straight (i.e., planar or flat) rib 150′ traversing the entire diameter of the opening 145 (i.e., nearly the entire diameter of the lumen of the aspiration catheter). Each end of the rib 150′ is affixed to the inner wall of a marker band section 135 located distally of the braided proximal section 130. To assist in disrupting, dividing, cutting, or tearing the clot, the distal edges of the rib may optionally be sharpened (acting as a blade or knife) to assist in “cutting” the clot during bidirectional movement back and forth between the clot and the rib 150′ when under cyclic suction. However, even ribs 150' with blunt distal edges, when combined with periodic suction, will disrupt, divide, cut, or tear the clot, although less effectively than if they were sharp.

[0019] 1A-1H and 9A-9E all operate similarly in that the clot is disrupted, divided, cut, or torn with each pass (i.e., back and forth) across an internal structural obstacle (e.g., one or more wires, fibers, or ribs) during cyclic suction. Specifically, during vacuum pressure intervals, the clot traverses the internal structural obstacle (e.g., one or more wires, fibers, or ribs) in a proximal direction from distal to proximal. Meanwhile, during positive pressure intervals, the clot traverses the internal structural obstacle in a distal direction from proximal to distal. During the relative movement between the clot and the non-powered internal structural obstacle in response to the cyclic suction pressure waveform, the clot is disrupted, divided, cut, or torn.

[0020] In the above-described examples of wires, fibers, or ribs as non-powered internal structural obstructions, each respective end is attached to another component (e.g., the inner wall of a marker band section, directly to the inner wall of the aspiration catheter, or, in the case of a three-segment fiber, to each other). However, according to the present disclosure, it is possible for only one end of the internal structural obstruction to be attached and secured, while the opposite end remains free (i.e., not attached to any other component). One example of such a configuration is an internal structural obstruction including one or more radial fins 250, each fin 250 secured at only one end to the inner wall of the marker band 235 and its opposite second end protruding freely into the lumen of the aspiration catheter perpendicular to the inner wall. While FIG. 2 schematically illustrates an internal structural member including four radially equidistantly spaced fins 250, any number of one or more fins is contemplated, and their placement along the inner wall of the maker band 235 need not necessarily be equidistant from one another. When cyclic suction is applied, the radial fins 250 can generate a suction vortex proximate the distal tip / end of the aspiration catheter, which further assists in cutting, macerating, or tearing apart the clot. Preferably, the radial fins 250 are all curved in the same direction (e.g., clockwise or counterclockwise). The generated suction vortex, combined with the induced movement of the clot against the radial fins during cyclic suction, facilitates the disruption or tearing of the clot.

[0021] The radial cutting element can be arranged as a ring of helical teeth affixed to the inner wall of the aspiration catheter's lumen. FIG. 3A shows the distal end of a ring of helical teeth 350 disposed within the aspiration catheter's lumen. Each helical tooth is affixed at one end along the inner surface of the aspiration catheter, with its opposite free end projecting radially inward to assist in macerating, disrupting, or tearing the clot during engagement under cyclic suction. In an alternative configuration, FIG. 3B, the non-powered internal structural obstruction is a ring of helical blades 350′, each attached at one end 350′c to the inner wall of the aspiration catheter 305 and with its free tip projecting into the lumen. The helical blades 350′ are preferably deflectable or deformable when engaging either (i) a clot while under vacuum pressure or (ii) an auxiliary device (e.g., an inner catheter) during distal advancement through the aspiration catheter's lumen. To facilitate flexing or deformation during engagement with a clot or an auxiliary device, each blade 350' preferably has a distally facing edge 350'a that protrudes inward relative to the opposing proximal facing edge 350'b, as shown in FIG. 3C. Distally, upon application of vacuum pressure, the clot, as it moves proximally, engages (i.e., captures) distally facing edge 350'a, lifting or elevating the blade away from the inner wall of the aspiration catheter, thereby increasing its engagement therewith. Meanwhile, proximally, as the auxiliary device (e.g., inner catheter) advances distally through the lumen of the aspiration catheter, it engages (i.e., brushes over) proximally facing edge 350'b, folding, pushing, and deforming the blade toward the inner wall of the aspiration catheter, thereby allowing it to pass therethrough.

[0022] In yet another example, shown in the axial cross-sectional views of Figures 4A-4C, an aspiration catheter 405 includes a ring of saw teeth 450 as a non-powered internal structural obstruction. Preferably, the saw teeth 450 face proximally (i.e., are angled or sloped proximally) and are made of a biocompatible elastomeric polymer material that is deflectable to accommodate a clot 460 thereon during vacuum pressure. The perspective view of the distal section of the aspiration catheter 405 in Figure 4B and the axial cross-sectional view of the distal section in Figure 4C show that the saw teeth 450 are deflected to allow the clot 460 to pass through while being entrapped in the lumen of the aspiration catheter 405 during vacuum pressure. The application of cyclic suction results in a back-and-forth relative movement between the clot and the ring of saw teeth 450 (as represented by the double-headed arrow in Figure 4B), macerating, disrupting, cutting, and tearing the clot 460. 4C is a longitudinal cross-sectional view of the distal section of aspiration catheter 405 showing proximally facing (i.e., angled or sloped proximally) and deflectable (as indicated by the respective curved arrows) serrations 450 that contain the clot during passage through vacuum pressure, while during intervals of positive pressure, the proximally facing serrations 450 pierce the clot 460, assisting in clot fragmentation, restraining the clot to minimize distal migration, and / or changing the shape of the clot (e.g., elongating it).

[0023] 4A-4C, multiple, separate, individual spikes or tines 550 (resembling fork tines or piranha tines) may be disposed along the inner wall of the suction catheter 505. Each spike or tine 550 has one end affixed to the inner wall of the suction catheter 505, and its opposite, free end preferably faces proximally (i.e., is angled or sloped in the proximal direction) (FIG. 5A). During intervals of positive pressure, the proximally facing spikes or tines 550 pierce the clot to help fragment it, restrain it to minimize distal migration, and / or change the shape of the clot (e.g., elongate it). The spikes or tines of multiple rings 550a, 550b, 550c of spikes or tines (i.e., the spikes or tines of any one ring are in the same radial plane) may be arranged in series axially, with the size of the spikes or tines of any particular ring 550a, 550b, 550c (i.e., the extent to which the spikes or tines protrude radially inward into the lumen of the aspiration catheter 505) decreasing proximally relative to the more distal ones (FIG. 5A). That is, the spikes or tines of ring 550a are larger than the spikes or tines of ring 550b, which are larger than the spikes or tines of ring 550c. Preferably, the spikes or tines of any one ring 550a, 550b, 550c (i.e., in the same radial plane) are substantially equal in size.

[0024] The inner wall of the aspiration catheter 705, or an inner lining otherwise permanently affixed thereto, can have its distal section formed with a shaped, non-uniform inner diameter that serves as a non-powered internal structural obstacle. Figures 7A and 7B show a cross section of the inner wall of the aspiration catheter 705 having multiple circumferential, tapered, molded or thermoformed ribs 750 arranged axially in series, one after the other. Each of the multiple molded or thermoformed circumferential ribs 750 is preferably tapered, with its widest diameter closest to the distal tip / end of the aspiration catheter 705 and its narrowest diameter further from the distal tip / end of the aspiration catheter 705. Additionally, the molded or thermoformed edges of the circumferential profile may optionally be sharpened to facilitate maceration, disruption, or tearing of the outer surface of the clot 760 during engagement. During vacuum pressure, the clot 760 engages the shaped ribs 750 to assist in entrapment. Meanwhile, during positive pressure, shaping ribs 750 minimize distal springback (eg, relaxation) of clot 760 in the distal direction and / or cause the clot to change shape (eg, stretch).

[0025] In yet another example, the internal structural obstruction may be a flap 850 disposed in the distal section of the lumen of the suction catheter 805. The flap 850 is preferably made of a polymeric material and is transitionable between an open state and a closed state in response to periodic suction. FIG. 8A shows an exemplary suction catheter 805 having two sets of flaps 850 arranged axially / longitudinally in succession. Any number of sets of flaps is contemplated, preferably more than one, and most preferably two. Each flap is affixed at its distal end to the inner wall of the suction catheter 805. The opposing free proximal ends of the flaps are transitionable between an open state (a maximum distance apart from each other) and a closed state (drawn together, preferably in physical contact with each other). During positive pressure, the flaps 850 are maintained in an open state, allowing blood flow therethrough (FIG. 8B, before clot entrapment). Upon application of positive pressure, flap 850 transitions to a closed state, preventing distal blood flow therethrough (FIG. 8C, before clot entrapment). The opening and closing of flap 850 during clot entrapment are shown in FIGS. 8D-8F. Prior to application of the cyclic suction pressure waveform, in a preliminary step of the thrombectomy procedure, the distal end of aspiration catheter 805 is advanced through the vessel to the proximal side / face of clot 860 (FIG. 8D). During this preliminary step, flap 850 is in an open state. Once the aspiration catheter is properly positioned within the vessel, the cyclic suction pressure waveform is applied. As shown in FIG. 8E, while flap 850 is in an open state during application of vacuum pressure (as indicated by the arrow on the right), clot 860 is entrapped proximally at the distal end of aspiration catheter 805. During entrapment, if the clot diameter is sufficiently large, flaps 850 (already in an open state) may be further displaced even wider (i.e., greater separation of their respective free proximal ends from each other) to accommodate the clot passing therethrough. This enhanced, greater, or increased spread of the already open state of flaps 850 disposed closest to the distal end of the catheter to accommodate the clot during its passage is shown in FIG. 8E, compared to the smaller separation of proximal flaps 850 that have not yet been traversed by the clot. Subsequently, application of positive pressure causes flaps 850 to close, as shown in FIG. 8F.The use of multiple axial sets of flaps provides a synergistic effect resulting from the individual performance of each set of flaps 850 while in a closed state, as shown in FIG. 8F. That is, closure of the most distal set of flaps 850 clamps or pinches the trapped clot, simultaneously assisting in tearing it while minimizing the risk of leakage during positive pressure. Correspondingly, closure of the more proximal set of flaps 850 (not yet traversed by the clot) prevents the backflow of blood therethrough when subjected to positive pressure. To this end, the non-powered internal structural obstruction preferably includes at least two sets of flaps 850 arranged axially in series, one behind the other. Thus, the movement of the flaps in Figures 8A-8F may be in response to (i) a cyclic aspiration pressure waveform (i.e., vacuum and positive pressure), (ii) movement of the clot through the aspiration catheter under vacuum pressure that widens the opening between the flaps to accommodate passage therethrough, and / or (iii) movement of an assist device when advanced distally through the aspiration catheter, widening the opening in the flap to accommodate passage therethrough.

[0026] In any of the above examples, when subjected to cyclic suction, the clot experiences a primary vibration effect during the relative axial movement (i.e., back and forth) between the clot and the non-powered internal structural obstruction. The efficiency of clot tearing can be enhanced or optimized by providing a supplemental vibration effect in addition to the primary vibration effect. In the example of FIGS. 6A and 6B, the secondary vibration effect is axial compression or squeezing between the clot and the non-powered internal structural obstruction. This supplemental vibration effect of axial compression can be achieved by aspiration catheter 605 including an axially compressible spring section 650, shown in both an expanded (i.e., uncompressed or uncontracted) state ( FIG. 6A ) and a compressed (i.e., collapsed or contracted) state ( FIG. 6B ). The axially compressible spring section 650 can be fabricated, for example, using a helical coil or a section of low durometer material (e.g., similar to Chinese lantern). When subjected to cyclic suction, the clot simultaneously undergoes a primary oscillatory effect, i.e., a back-and-forth axial movement (as indicated by the double-headed arrows) of relative movement between the clot and any one of the exemplary non-powered internal structural obstacles described above. Simultaneously, the axially compressible spring section 650, when subjected to cyclic suction, imparts a complementary oscillatory effect of alternating contraction ( FIG. 6B ) and expansion ( FIG. 6A ) (as indicated by the respective double-headed arrows), thereby compressing and elongating the internal clot, similar to the oscillatory effect of a jackhammer. Thus, clot fragmentation, division, or tearing is more efficient when the primary oscillatory effect (i.e., a back-and-forth movement) imposed on the clot using any one of the exemplary non-powered internal structural obstacles described above and the complementary oscillatory effect of axial compression and elongation of the clot occur simultaneously during cyclic suction.

[0027] While the examples above describe non-powered internal structural obstructions that are permanently fixed in axial position within the lumen of the aspiration catheter, all of the examples described below relate to non-powered internal structural obstructions as separate devices or components that are independently slidable within the lumen of the aspiration catheter.

[0028] In the example of FIGS. 10A-10D, the periodic suction catheter system includes a suction catheter 1005 having a lumen 1020 defined therein. The system further includes a non-powered internal structural obstruction 1010 as a separate component slidably received within the lumen 1020 of the suction catheter 1005 (i.e., capable of being pushed distally), as shown in the exploded view of FIG. 10D. In the example of FIGS. 10A-10D, the non-powered internal structural obstruction includes an axially extending shaft 1025 (i.e., a pushing member) with a cutting head secured to the distal end of the shaft 1025. The cutting head optionally includes an outer circular frame 1035 disposed concentrically with the shaft 1025. As shown in the side view of FIG. 10A, the outer circular frame 1035 is preferably disposed proximally relative to the distal end of the shaft 1025. The plurality of blades 1030 are secured between the distal end of the shaft 1025 and an outer circular frame 1035. Alternatively, the outer circular frame 1035 may be eliminated entirely, with each blade 1030 secured to the shaft 1025 at only one end and the opposite end being free (i.e., not attached to any other component). Each of the blades 1030 preferably has a sharp, distally facing edge to facilitate disrupting, dividing, cutting, or tearing apart clots moving relative thereto when subjected to periodic suction. To further assist in disrupting clots, the blades are preferably angled at an acute angle relative to the shaft 1025, rather than projecting radially outward perpendicular to the shaft 1025. That is, the blades are preferably positioned such that their respective proximal ends lie in a first common radial plane and their respective distal ends lie in a second common radial plane distal to the first common radial plane. 10A-10D are angled proximally outward, away from the shaft 1025, but may alternatively be disposed in the opposite direction, angled proximally inward, toward the shaft 1025. Additionally, the distally facing edge of each blade 1050 in the example of FIGS. 10A-10D has a concave contour or profile to aid in disrupting the clot, but could also have a convex or straight profile.10A-10D show an example of a disruption head having four blades 1030 evenly spaced radially. However, any number of one or more blades and their arrangement on the disruption head may be selected as desired. Once the non-powered internal structural obstruction 1010 is properly positioned within the aspiration catheter, it may optionally be locked into place (e.g., by tightening a proximal hemostatic valve attached to the catheter hub around its shaft) or simply held in place by the interventionalist.

[0029] During operation, either serially one after the other or together as an assembled unit, the aspiration catheter 1005 and the separate non-powered internal structural obstruction 1010 are delivered through the blood vessel to a target site proximal to a target clot to be captured. As the two separate components navigate through the blood vessel in succession, the aspiration catheter 1005 is delivered first through the blood vessel to a target site proximal / face of the target clot. Once the aspiration catheter 1005 is properly positioned within the blood vessel at the target site, the non-powered internal structural obstruction 1010 is then advanced (i.e., pushed or slid) distally through the lumen 1020 of the aspiration catheter 1005 using the shaft 1025. Advancement of the non-powered internal structural obstruction 1010 into the lumen 1020 of the aspiration catheter 1005 stops proximal to the distal tip / end, preferably leaving a free space 140 between the respective distal ends of the aspiration catheter 1005 and the non-powered internal structural obstruction 1010. Alternatively, when two separate components are navigated through a blood vessel together as an assembled unit, prior to introduction into the body, the non-powered internal structural obstruction 1010 is advanced (i.e., slid or pushed) using the shaft 1025 through the lumen 1020 to a desired location proximal to the distal tip of the aspiration catheter 1005, forming the assembled unit. The assembled unit is then delivered through the blood vessel to a target site on the proximal side / face of the target clot. Whether the aspiration catheter 1005 and non-powered internal structural obstruction 1010 are delivered through the blood vessel to the target site sequentially or together as an assembled unit, once properly positioned at the target site, cyclic suction is applied to capture the clot. The non-powered internal structural obstruction 1010 does not require its own power source or associated components (e.g., motor, gears, etc.) to impart axial oscillation and / or rotation. Rather, the clot is disrupted solely by utilizing the kinetic energy imparted by the periodic suction pressure waveform, which induces movement of the clot relative to the non-powered internal structural obstacle and induces axial vibration in the non-powered internal structural obstacle, including its associated cutting element.By simplifying and minimizing the number of non-powered internal structural obstruction components in this manner, the bulk, footprint, weight, and cost of the cyclical suction system according to the present disclosure are minimized.

[0030] Another example of a non-powered internal structural obstruction according to the present disclosure is shown in FIGS. 11A-11D. The non-powered internal structural obstruction (shown in side view in FIG. 11A) is a wire 1125 (e.g., a guidewire) having multiple cutting elements (e.g., teeth or serrated edge(s)) 1130 disposed along its distal section. The cutting elements 1130 may be made from a biocompatible polymeric material, and the number thereof may be selected as desired. Furthermore, the shape and size of each of the cutting elements 1130 may be the same or different. The cutting elements 1130 are preferably angled or sloped in a deflectable proximal direction to allow clots to pass over them while being captured at the distal tip / end of the aspiration catheter during vacuum pressure. During positive pressure, the proximal angled cutting element 1130 pierces the clot, tears it apart, and restrains the clot in place, minimizing distal migration and / or changing its shape (e.g., elongated). If the clot remains in place when pierced by the cutting element 1130, a maximum level of positive pressure can be applied without risk of expelling the clot from the distal end / tip of the aspiration catheter.

[0031] The wire 1125 is formed or heat-set into a desired preformed shape. In a preferred configuration shown in FIG. 2A, the wire 1125 is preformed to have a linear (i.e., straight) proximal section 1125a, a substantially parallel linear (i.e., straight) distal section 1125c, and a nonlinear transition section 1125b therebetween. Preferably, the preformed shape of the wire 1125 is such that, when split axially in the middle, the distal half is inverted both axially and laterally relative to the proximal half. The linear proximal and distal sections 1125a, 1125c extend axially and are laterally separated from each other by a predetermined distance (i.e., width W) by the transition section 1125c. During formation of the wire 1125, the predetermined lateral distance separation (i.e., width W) of the linear proximal and distal sections 1125a, 1125c relative to one another is preferably substantially equal to the inner diameter of the lumen 1120 of the aspiration catheter 1105 through which the non-powered internal structural obstruction 1125 is advanced. Thus, as shown in FIG. 11B , when the non-powered internal structural obstruction 1125 is introduced, slid, or advanced within the lumen 1140 of the aspiration catheter 1105, the respective linear proximal and distal sections 1125a, 1125c are in direct physical contact with the inner wall of the lumen 1140 of the aspiration catheter 1105, ensuring maximum open space within the lumen 1140 radially inward of the cutting elements (e.g., teeth 1130) into which clots may become entrapped. To maintain the linear distal section 1125c of the wire 1125 in substantially direct physical contact with the inner wall of the lumen of the aspiration catheter, thereby ensuring that the cutting element 1130 (e.g., teeth) protrudes and is properly positioned within the lumen, the distal tip / end of the wire 1135 itself, or a separate wire segment attached thereto, can be formed into a distal loop or ring 1135 (FIG. 11G). The distal loop or ring 1135 is closed, but may also be open, forming a "C" shape.

[0032] Multiple wires can be used to form the non-powered internal structural obstruction. Figures 11E and 11F are side and perspective views, respectively, of an exemplary multi-wire non-powered internal structural obstruction formed using four wires 1125. Starting from the distal tip / end, each of the four wires 1125 includes a linear distal section 1125c, a transition section 1125b, and a linear proximal section 1125d. The linear proximal section 1125b where each of the four wires meet can be twisted together to provide additional reinforcement and support as a pushing member when advancing the non-powered internal structural obstruction distally through the lumen to a desired location within the distal section of the aspiration catheter. Alternatively, each of the four wires 1125 can be joined at their respective proximal ends to a separate fifth wire that extends proximally and functions as a pushing member when advancing the non-powered internal structural obstruction distally through the lumen to a desired location within the distal section of the aspiration catheter. The four wires 1125 are radially spaced equidistant from one another in FIGS. 11E and 11F, but may be positioned as desired. Furthermore, the preformed wires 1125 are positioned such that their linear distal sections 1125c are in substantially direct physical contact with the inner wall of the aspiration catheter lumen as they advance through the aspiration catheter. Multiple cutting elements 1130 (e.g., sawtooth teeth) are secured along some, and preferably all, distal sections of the wires 1125. As an illustrative example, the non-powered internal structural obstruction in FIGS. 11E and 11F is formed with four wires, although any number of wires greater than or equal to two may be used. Similar to the single wire in FIG. 11G, a single distal loop or ring (closed or open, forming a "C") may be secured to each of the individual distal ends of the four wires 1125 to maintain proper positioning of the cutting elements 1130 (e.g., teeth).

[0033] In operation, either serially one after the other or together as an assembled unit, the aspiration catheter 1105 and a separate non-powered internal structural obstruction 1125 (e.g., a single wire or multiple wires joined together) are delivered through a blood vessel to a target site proximal / on the side of a target clot to be captured. As the two separate components are navigated through a blood vessel independently and sequentially, the aspiration catheter 1105 is delivered first through the blood vessel to a target site proximal / on the side of a target clot. Once the aspiration catheter 1105 is properly positioned within the blood vessel at the target site, using its proximal end, the non-powered internal structural obstruction 1125 (e.g., a single wire or multiple wires joined together) is then advanced (i.e., pushed or slid) distally through the lumen 1120 of the aspiration catheter 1105. Advancement of the non-powered internal structural obstruction 1125 (e.g., a single wire or multiple wires joined together) into the lumen 1120 of the aspiration catheter 1105 stops proximal to the distal tip / end of the aspiration catheter 1105. Alternatively, if two separate components are to be navigated through the blood vessel together as an assembled unit, prior to introduction into the body, the proximal end is used to advance (i.e., slide or push) the non-powered internal structural obstruction 1125 (e.g., a single wire or multiple wires joined together) through the lumen 1120 to a desired location in the distal section of the aspiration catheter 1105 proximal to the distal tip / end that will form the assembled unit. The assembled unit is then delivered through the blood vessel to a target site on the proximal side / face of the target clot. Whether the suction catheter 1105 and non-powered internal structural obstruction 1125 (e.g., a single wire or multiple wires joined together) are delivered serially or together as an assembled unit through a blood vessel to a target site, once properly positioned at the target site, cyclic suction is applied to capture the clot. Neither the non-powered internal structural obstruction 1125 (e.g., a single wire or multiple wires joined together) nor its associated cutting element 1130 requires its own power source or associated components (e.g., motor, gears, etc.) to impart axial oscillation and / or rotation.Rather, the clot is disrupted solely by utilizing kinetic energy imparted by a cyclic suction pressure waveform that induces relative movement between the clot and a cutting element 1130 disposed along a distal section of the non-powered internal structural obstruction 1125 (e.g., a single wire or multiple wires joined together). By simplifying and minimizing the number of components of the non-powered internal structural obstruction in this manner, the bulk, footprint, weight, and cost of the cyclic suction system according to the present disclosure are minimized.

[0034] For each of the above-described examples of non-powered internal structural obstructions (e.g., Figures 10A-10D and 11A-11G) that represent separate components independent of and slidable within the lumen of the aspiration catheter, a tight seal is provided between the catheter hub and the shaft or wire, thereby ensuring that the cyclic aspiration pressure waveform is not affected as the non-powered internal structural obstruction advances.

[0035] Aspects of the present disclosure are also provided by the following numbered callouts:

[0036] Appendix 1 The cyclic suction system includes a suction catheter (105) having a proximal end (110) and an opposite distal end (115), and respective outer and inner walls extending longitudinally from the proximal end (110) to the distal end (115) and defining a lumen therein; and a cyclic suction source (1200) connected in fluid communication to the proximal end (110) of the suction catheter (105), the cyclic suction pressure source (1200) generating a cyclic suction pressure waveform with intermittent cycles of a vacuum pressure below atmospheric pressure and a positive pressure higher than the vacuum pressure; and a non-powered internal structural obstruction (1200) disposed within the lumen of the suction catheter. 50, 150', 250, 350, 350', 450, 550, 650, 750, 850, 950, 1010, 1125), a cyclic suction system comprising: a blood clot captureable therein; and a non-powered internal structural obstacle (150, 150', 250, 350, 350', 450, 550, 650, 750, 850, 950, 1010, 1125) configured to engage during resultant movement between the blood clot and the non-powered internal structural obstacle (150, 150', 250, 350, 350', 450, 550, 650, 750, 850, 950, 1010, 1125) while subjected to a cyclic suction pressure waveform.

[0037] Appendix 2 The cyclic suction system of Appendix 1, wherein engagement of the internally captureable blood clot with the non-powered internal structural obstacle (150, 150', 250, 350, 350', 450, 550, 650, 750, 850, 950, 1010, 1125) results in (i) breaking down the structure of the internally captureable blood clot from a single, integral structure into multiple clot fragments, (ii) changing the shape of at least a portion of the internally captureable blood clot, and / or (iii) restricting distal movement of the internally captureable blood clot.

[0038] Appendix 3 3. The cyclic suction system of claim 1 or 2, wherein movement between the clot and the non-powered internal structural obstacle (150, 150', 250, 350, 350', 450, 550, 650, 750, 850, 950, 1010, 1125) is bidirectional.

[0039] Appendix 4 The periodic suction system of any one of claims 1 to 3, wherein the non-powered internal structural obstruction (150, 150', 250, 350, 350', 450, 550, 650, 750, 850, 950, 1010, 1125) protrudes into or traverses at least a portion of the lumen of the suction catheter (105).

[0040] Appendix 5 5. The cyclical suction system of any one of claims 1 to 4, wherein the non-powered internal structural obstruction (150, 150', 250, 350, 350', 450, 550) is a wire, fiber, strut, rib, tooth, blade, or spike.

[0041] Appendix 6 5. The cyclical suction system of any one of clauses 1-4, wherein the non-powered internal structural obstruction is a flap (850) that is transitionable between an open state and a closed state.

[0042] Appendix 7 5. The cyclic aspiration system of any one of claims 1 to 4, wherein the non-powered internal structural obstruction is a section (750) along the inner wall of the lumen of the aspiration catheter (105) having an uneven contour.

[0043] Appendix 8 The cyclic suction system of any one of claims 1 to 7, further comprising an auxiliary non-powered internal structural obstacle as a section (650) of the suction catheter (105) that is axially compressible and expandable with a blood clot captureable therein in response to a cyclic suction pressure waveform.

[0044] Appendix 9 9. The cyclic suction system of any one of claims 1 to 8, wherein the non-powered internal structural obstruction (150, 150', 250, 350, 350', 450, 550, 650, 750, 850, 950, 1010, 1125) is either (i) permanently fixed within the lumen of the suction catheter (105) or (ii) is a separate component in the form of a shaft or wire having multiple cutting elements that is slidable within the lumen of the suction catheter (105).

[0045] Appendix 10 10. The cyclic suction system of any one of claims 1 to 9, wherein the cyclic suction source (1200) is a pulsatile vacuum pump.

[0046] Appendix 11 A method for using a cyclic suction system, the cyclic suction system comprising: a suction catheter (105) having a proximal end (110), an opposite distal end (115), and respective outer and inner walls extending longitudinally from the proximal end (110) to the distal end (115) and defining a lumen therein; and a cyclic suction source (1200) connected in fluid communication to the proximal end of the suction catheter, the cyclic suction pressure source intermittently cycling between a vacuum pressure below atmospheric pressure and a positive pressure higher than the vacuum pressure. a periodic suction source generating a periodic suction pressure waveform at intervals of 100 suction pulses; and a non-powered internal structural obstacle (150, 150', 250, 350, 350', 450, 550, 650, 750, 850, 950, 1010, 1125) disposed within the lumen of the aspiration catheter, the non-powered internal structural obstacle (150, 150', 250, 350, 350', 450, 550, 650, 750, 850, 950, 1010, 1125) configured to engage a captureable blood clot therein and during resulting movement between the blood clot and the internal structural obstacle while being subjected to the periodic suction pressure waveform. and a non-powered internal structural obstruction (150, 150', 250, 350, 350', 450, 550, 650, 750, 850, 950, 1010, 1125), the method comprising the steps of advancing, either simultaneously or sequentially, an aspiration catheter (105) and a non-powered internal structural obstruction (150, 150', 250, 350, 350', 450, 550, 650, 750, 850, 950, 1010, 1125) through a blood vessel to a target site proximal to the clot; and applying a periodic aspiration pressure waveform to the aspiration catheter (105). , capturing the blood clot; and engaging the blood clot with a non-powered internal structural obstacle (150, 150', 250, 350, 350', 450, 550, 650, 750, 850, 950, 1010, 1125) during a resulting relative movement between the blood clot and the non-powered internal structural obstacle (150, 150', 250, 350, 350', 450, 550, 650, 750, 850, 950, 1010, 1125) while subjected to a periodic suction pressure waveform.

[0047] Appendix 12 12. The method of claim 11, wherein the engaging step results in (i) breaking down the structure of the clot from a single, integral structure into multiple clot fragments, (ii) changing the shape of at least a portion of the clot, and / or (iii) restricting distal movement of the clot.

[0048] Appendix 13 13. The method of claim 11 or 12, wherein the relative movement is bidirectional movement.

[0049] Appendix 14 14. The method of any one of claims 11 to 13, wherein the non-powered internal structural obstruction (150, 150', 250, 350, 350', 450, 550, 650, 750, 850, 950, 1010, 1125) protrudes into or traverses at least a portion of the lumen of the aspiration catheter.

[0050] Appendix 15 15. The method of any one of claims 11 to 14, wherein the non-powered internal structural obstruction (150, 150', 250, 350, 350', 450, 550) protrudes into the lumen of the aspiration catheter and is a wire, fiber, strut, rib, tooth, blade, or spike.

[0051] Appendix 16 16. The method of any one of claims 11 to 15, wherein the non-powered internal structural obstacle (250, 350, 350') generates a suction vortex.

[0052] Appendix 17 15. The method of any one of claims 11 to 14, wherein the non-powered internal structural obstruction is a flap (850) that is transitionable between an open state and a closed state in response to (i) a periodic suction pressure waveform, (ii) clot movement, and / or (iii) an auxiliary device advanced distally through the lumen of the suction catheter (105).

[0053] Appendix 18 15. The method of any one of claims 11 to 14, wherein the non-powered internal structural obstruction is a section (750) along the inner wall of the aspiration catheter (105) having an uneven contour.

[0054] Appendix 19 19. The method of any one of claims 11 to 18, further comprising providing an auxiliary non-powered internal structural obstacle as a section (605) of the suction catheter (105) that is axially compressible and expandable with a blood clot captureable therein in response to a periodic suction pressure waveform.

[0055] Appendix 20 9. The cyclic suction system of any one of claims 1 to 8, wherein the non-powered internal structural obstruction (150, 150', 250, 350, 350', 450, 550, 650, 750, 850, 950, 1010, 1125) is either (i) permanently fixed within the lumen of the suction catheter (105) or (ii) is a separate component in the form of a shaft or wire having multiple cutting elements that is slidable within the lumen of the suction catheter (105).

[0056] The descriptions contained herein are examples and are not intended to limit the scope of the present disclosure in any way. As described herein, the present disclosure contemplates many variations and modifications of aspiration catheters that include a non-powered internal structural obstruction and an associated cutting element to assist in capturing a blood clot when under cyclic suction. Variations and modifications obvious to those skilled in the art in light of the teachings of the present disclosure are intended to be within the scope of the following claims.

[0057] [Embodiment] (1) A cyclic suction system comprising: a suction catheter having a proximal end, an opposite distal end, and respective outer and inner walls extending longitudinally from the proximal end to the distal end and defining a lumen therein; a periodic suction source connected in fluid communication with the proximal end of the suction catheter, the periodic suction pressure source generating a periodic suction pressure waveform with intermittent cycles of a vacuum pressure below atmospheric pressure and a positive pressure greater than the vacuum pressure; A cyclic aspiration system comprising: a non-powered internal structural obstacle disposed within the lumen of the aspiration catheter, the non-powered internal structural obstacle configured to engage a blood clot captureable therein and during resulting movement between the blood clot and the non-powered internal structural obstacle while subjected to the cyclic aspiration pressure waveform. (2) The cyclic suction system of embodiment 1, wherein the engagement of the internally captureable blood clot with the non-powered internal structural obstacle results in (i) breaking down the structure of the internally captureable blood clot from a single, integral structure into multiple clot fragments, (ii) changing the shape of at least a portion of the internally captureable blood clot, and / or (iii) restricting distal movement of the internally captureable blood clot. (3) A cyclic suction system as described in embodiment 1, wherein movement between the blood clot and the non-powered internal structural obstacle is bidirectional. (4) A cyclic suction system as described in embodiment 1, wherein the non-powered internal structural obstacle protrudes into or traverses at least a portion of the lumen of the suction catheter. (5) The cyclic suction system of embodiment 1, wherein the non-powered internal structural obstacle is a wire, fiber, strut, rib, tooth, blade, or spike.

[0058] (6) The cyclic suction system of embodiment 1, wherein the non-powered internal structural obstruction is a flap that is transitionable between an open state and a closed state. (7) The cyclic aspiration system of embodiment 1, wherein the non-powered internal structural obstruction is a section along the inner wall of the lumen of the aspiration catheter having an uneven contour. (8) The cyclic suction system of embodiment 1 further comprises an auxiliary non-powered internal structural obstacle as a section of the suction catheter that is axially compressible and expandable together with the blood clot that can be captured therein in response to the cyclic suction pressure waveform. (9) The cyclic suction system of embodiment 1, wherein the non-powered internal structural obstruction is (i) permanently fixed within the lumen of the suction catheter or (ii) a separate component in the form of a shaft or wire having multiple cutting elements that is slidable within the lumen of the suction catheter. (10) The cyclic suction system of embodiment 1, wherein the cyclic suction source is a pulsating vacuum pump.

[0059] (11) A method for using a cyclic suction system, the cyclic suction system including: a suction catheter having a proximal end, an opposite distal end, and respective outer and inner walls extending longitudinally from the proximal end to the distal end and defining a lumen therein; a cyclic suction source connected in fluid communication with the proximal end of the suction catheter, the cyclic suction pressure source generating a cyclic suction pressure waveform with intermittent cycles of a vacuum pressure below atmospheric pressure and a positive pressure higher than the vacuum pressure; and a non-powered internal structural obstacle disposed within the lumen of the suction catheter, the non-powered internal structural obstacle configured to engage a captureable blood clot therein and during resulting movement between the blood clot and the internal structural obstacle while subjected to the cyclic suction pressure waveform, the method comprising: advancing, either simultaneously or sequentially, the aspiration catheter and the non-powered internal structural obstruction through the blood vessel to a target site proximal to the clot; applying the periodic aspiration pressure waveform to the aspiration catheter to capture the clot; and engaging the clot with the non-powered internal structural obstacle during the resulting relative movement between the clot and the non-powered internal structural obstacle while subjected to the cyclic suction pressure waveform. (12) The method of embodiment 11, wherein the engaging step results in (i) breaking down the structure of the clot from a single, monolithic structure into multiple clot fragments, (ii) changing the shape of at least a portion of the clot, and / or (iii) restricting distal movement of the clot. (13) The method of embodiment 11, wherein the relative movement is bidirectional movement. (14) The method of embodiment 11, wherein the non-powered internal structural obstruction protrudes into or traverses at least a portion of the lumen of the aspiration catheter. (15) The method of embodiment 11, wherein the non-powered internal structural obstruction protrudes into the lumen of the suction catheter and is a wire, fiber, strut, rib, tooth, blade, or spike.

[0060] (16) The method of claim 15, wherein the non-powered internal structural obstacle generates a suction vortex. (17) The method of embodiment 11, wherein the non-powered internal structural obstruction is a flap that is transitionable between an open state and a closed state in response to (i) the periodic suction pressure waveform, (ii) the movement of the clot, and / or (iii) an auxiliary device advanced distally through the lumen of the suction catheter. (18) The method of embodiment 11, wherein the non-powered internal structural obstruction is a section along the inner wall of the aspiration catheter having an uneven contour. (19) The method of embodiment 11, further comprising an auxiliary non-powered internal structural obstacle as a section of the aspiration catheter axially compressible and expandable with the clot captured therein in response to the cyclic aspiration pressure waveform. (20) The method of embodiment 11, wherein the non-powered internal structural obstruction is (i) permanently fixed within the lumen of the suction catheter, or (ii) a separate component in the form of a shaft or wire that is slidable within the lumen of the suction catheter and has multiple cutting elements.

Claims

1. 1. A cyclic aspiration system comprising: a suction catheter having a proximal end, an opposite distal end, and respective outer and inner walls extending longitudinally from the proximal end to the distal end and defining a lumen therein; a periodic suction source connected in fluid communication with the proximal end of the suction catheter, the periodic suction pressure source generating a periodic suction pressure waveform with intermittent cycles of a vacuum pressure below atmospheric pressure and a positive pressure greater than the vacuum pressure; A cyclic aspiration system comprising: a non-powered internal structural obstacle disposed within the lumen of the aspiration catheter, the non-powered internal structural obstacle configured to engage a blood clot captureable therein and during resulting movement between the blood clot and the non-powered internal structural obstacle while subjected to the cyclic aspiration pressure waveform.

2. 2. The cyclic suction system of claim 1, wherein the engagement of the internally captureable blood clot with the non-powered internal structural obstacle results in (i) breaking down the structure of the internally captureable blood clot from a single, integral structure into multiple clot fragments, (ii) changing the shape of at least a portion of the internally captureable blood clot, and / or (iii) restricting distal movement of the internally captureable blood clot.

3. The cyclic aspiration system of claim 1 , wherein movement between the clot and the non-powered internal structural obstruction is bidirectional.

4. The cyclic aspiration system of claim 1 , wherein the non-powered internal structural obstruction protrudes into or traverses at least a portion of the lumen of the aspiration catheter.

5. The cyclical suction system of claim 1 , wherein the non-powered internal structural obstruction is a wire, fiber, strut, rib, tooth, blade, or spike.

6. The cyclical suction system of claim 1 , wherein the non-powered internal structural obstruction is a flap that is transitionable between an open and a closed state.

7. The cyclic aspiration system of claim 1 , wherein the non-powered internal structural obstruction is a section along the inner wall of the lumen of the aspiration catheter having a non-uniform contour.

8. 10. The cyclic aspiration system of claim 1, further comprising an auxiliary non-powered internal structural obstacle as a section of the aspiration catheter axially compressible and expandable with the clot captured therein in response to the cyclic aspiration pressure waveform.

9. 10. The cyclic aspiration system of claim 1, wherein the non-powered internal structural obstruction is either (i) permanently fixed within the lumen of the aspiration catheter or (ii) a separate component in the form of a shaft or wire that is slidable within the lumen of the aspiration catheter and has multiple cutting elements.

10. The cyclic suction system of claim 1 , wherein the cyclic suction source is a pulsatile vacuum pump.

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