Methods, systems, and devices for aspiration catheter suction relief or prevention

Abstract

Disclosed are embodiments of an aspiration catheter comprising an elongated shaft configured for placement within a blood vessel and a suction mitigation element. The elongated shaft has a distal end and an aspiration lumen extending therethrough. The suction mitigation element is disposed at or adjacent to the distal end of the elongate shaft and is configured to limit or prevent a wall of the blood vessel from being drawn into the aspiration lumen or being suctioned onto the distal end of the elongate shaft.

Description

METHODS, SYSTEMS, AND DEVICES FOR ASPIRATION CATHETER SUCTION RELIEF OR PREVENTIONInventors: Randolf von Oepen, Puneet Kamal Singh Gill, Stephanie Anne MaldonadoCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of United States Provisional Patent Application Serial No. 63 / 748,030, filed January 22, 2025, and entitled ’SYSTEMS, METHODS, AND DEVICES FOR ASPIRATION CATHETER SUCTION RELIEF OR PREVENTION,” the disclosure of which is incorporated herein by this reference.BACKGROUND OF THE INVENTIONTechnical Field

[0002] The present disclosure pertains generally to medical devices and methods of their use. More particularly, the present invention pertains to aspiration and thrombectomy devices and methods of use thereof.Description of the Related Art

[0003] Several devices and systems already exist to aid in the removal of thrombotic material. These include simple aspiration tube type devices using vacuum syringes to extract thrombus into the syringe, simple flush-and-aspirate devices, more complex devices with rotating components that pull in, macerate and transport thrombotic material away from the distal tip using a mechanical auger, and systems that use very high pressure to macerate the thrombus and create a venturi effect to flush the macerated material away.

[0004] All of the devices described above have limitations as a result of individual design characteristics. For example, while performing clot aspiration, a thrombectomy catheter may draw tissue, such as a vessel wall, into the catheter and suction onto the tissue in a way that can cause tissue damage.

[0005] As such, what is needed are systems, methods, and devices, that limit or prevent a thrombectomy catheter from suctioning onto tissue.SUMMARY

[0006] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not- Page 1 - Docket No. 22935.49aintended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0007] Implementations of the present disclosure solve one or more problems in the art with systems, methods, and devices for limiting or preventing a thrombectomy catheter from suctioning onto tissue. For instance, implementations of the present disclosure relate to aspiration systems that limiting or preventing a thrombectomy catheter from suctioning onto tissue. In one implementation, the aspiration system includes an elongated shaft configured for placement within a blood vessel and a suction mitigation element. The elongated shaft has a distal end and an aspiration lumen extending therethrough. The suction mitigation element is disposed at or adjacent to the distal end of the elongate shaft and is configured to limit or prevent a wall of the blood vessel from being drawn into the aspiration lumen or being suctioned onto the distal end of the elongate shaft. The suction mitigation element may take a variety of forms, including valves, deployable elements, balloons, coatings window s, grooves, slits, surface textures, and the like, and combinations thereof.

[0008] Additional features and advantages of exemplary implementations of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of such exemplary7implementations. The features and advantages of such implementations may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features will become more fully apparent from the following description and appended claims or may be learned by the practice of such exemplary implementations as set forth hereinafter.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Various objects, features, characteristics, and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings and the appended claims, all of which form a part of this specification. In the Drawings, like reference numerals may be utilized to designate corresponding or similar parts in the various Figures, and the various elements depicted are not necessarily drawn to scale, wherein:

[0010] Figure 1 is a plan view of exemplary7components of a system for aspirating thrombus according to an implementation of the present disclosure.- Page 2 - Docket No. 22935.49a

[0011] Figure 2 is a sectional view of an exemplary' distal end of the aspiration catheter of the system for aspirating thrombus of Figure 1 according to an implementation of the present disclosure.

[0012] Figure 3 is a detail view of an exemplary y-connector of the aspiration catheter of the system for aspirating thrombus of Figure 1 according to an implementation of the present disclosure.

[0013] Figure 4 is a plan view of exemplary components of a system for aspirating thrombus according to an implementation of the present disclosure.

[0014] Figure 5 is a perspective view of an exemplary system for aspirating thrombus of Figure 3 according to an implementation of the present disclosure.

[0015] Figure 6 is a perspective view of an exemplary’ aspiration catheter according to an implementation of the present disclosure.

[0016] Figure 7 is a sectional view of an exemplary aspiration catheter according to an implementation of the present disclosure.

[0017] Figure 8 illustrates the exemplary aspiration catheter within a body lumen aspirating thrombus according to an implementation of the present disclosure.

[0018] Figure 9 illustrates an aspiration catheter engaging a vessel wall.

[0019] Figures 10A-10B illustrate an exemplar}' aspiration catheter with a suction mitigation element according to an implementation of the present disclosure.

[0020] Figure 11 illustrates an exemplary aspiration catheter with a suction mitigation element according to an implementation of the present disclosure.

[0021] Figure 12 illustrates an exemplar ' aspiration catheter yvith a suction mitigation element according to an implementation of the present disclosure.

[0022] Figure 13 illustrates an exemplary aspiration catheter with a suction mitigation element according to an implementation of the present disclosure.

[0023] Figure 14 illustrates an exemplar}' aspiration catheter with a suction mitigation element according to an implementation of the present disclosure.

[0024] Figure 15 illustrates an exemplary aspiration catheter with a suction mitigation element according to an implementation of the present disclosure.

[0025] Figure 16 illustrates an exemplary aspiration catheter with a suction mitigation element according to an implementation of the present disclosure.

[0026] Figures 17A-17B illustrate an exemplar}' aspiration catheter with a suction mitigation element according to an implementation of the present disclosure.- Page 3 - Docket No. 22935.49a

[0027] Figures 18A-18B illustrate an exemplar}' aspiration catheter with a suction mitigation element according to an implementation of the present disclosure.

[0028] Figure 19 illustrates an exemplary aspiration catheter with a suction mitigation element according to an implementation of the present disclosure.

[0029] Figure 20 illustrates an exemplary aspiration catheter with a suction mitigation element according to an implementation of the present disclosure.

[0030] Figure 21 illustrates an exemplary aspiration catheter with a suction mitigation element according to an implementation of the present disclosure.

[0031] Figure 22 illustrates an exemplary' aspiration catheter with a suction mitigation element according to an implementation of the present disclosure.

[0032] Figure 23 illustrates an exemplary aspiration catheter with a suction mitigation element according to an implementation of the present disclosure.DETAILED DESCRIPTION

[0033] One or more specific embodiments of the present disclosure will be described below. In an effort to provide a concise description of these embodiments, some features of an actual embodiment may be described in the specification. It should be appreciated that in the development of any such actual embodiment, as in any engineering or design project, numerous embodiment-specific decisions will be made to achieve the developers’ specific goals, such as compliance with system-related and business-related constraints, which may vary from one embodiment to another. It should further be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary' skill having the benefit of this disclosure.

[0034] One or more embodiments of the present disclosure may generally relate to limiting or preventing an aspiration catheter from suctioning onto tissue, such as tissue of a body lumen (e.g., a vessel wall) receiving the aspiration catheter. A pressure relief element can be included in the aspiration catheter, which can limit or prevent the aspiration catheter from suctioning onto the tissue, thereby preventing tissue damage during aspiration of thrombus. Thus, the aspiration process is safer for a patient.

[0035] While the present disclosure will describe particular implementations for limiting or preventing an aspiration catheter from suctioning onto tissue during aspiration, it should be understood that the devices, systems, and method described herein may be applicable to other uses. Additionally, elements described in relation to any embodiment- Page 4 - Docket No. 22935.49adepicted and / or described herein may be combinable with elements described in relation to any other embodiment depicted and / or described herein.

[0036] A system 100 for aspirating thrombus is illustrated in Figures 1-5. The system 100 for aspirating thrombus includes a pump 101 , an aspiration catheter 102, and a tubing set 103. The aspiration catheter 102 and the tubing set 103 represent disposable components, and the pump 101, and the pump’s associated pump base, is a reusable component. It is not necessary to sterilize the pump 101 as it may be kept in anon-sterile field or area during use. The aspiration catheter 102 and the tubing set 103 may each be supplied sterile, after sterilization by ethylene oxide gas, electron beam, gamma, or other sterilization methods. The aspiration catheter 102 may be packaged and supplied separately from the tubing set 103. or the aspiration catheter 102 and the tubing set 103 may be packaged together and supplied together. Alternatively, the aspiration catheter 102 and tubing set 103 may be packaged separately, but supplied together (i.e., bundled).

[0037] The aspiration catheter 102 has a distal end 105 and includes an over-the-wire guidewire lumen / aspiration lumen 106 extending between an open distal end 107 and a proximal end 108 comprising ay-connector 110. The catheter shaft 111 of the aspiration catheter 102 is connected to the y-connector 110 via a protective strain relief 112. In other embodiments, the catheter shaft 111 may be attached to the y-connector 110 with a luer fitting. The y-connector 110 includes a first female luer 113 which communicates with a catheter supply lumen 114 (Figure 2). and a second female luer 115 which communicates with the guidewire lumen / aspiration lumen 106.

[0038] A spike 116 for coupling to a fluid source (e.g., saline bag, saline bottle) allows fluid to enter through an extension tubing 118 and flow into a supply tube 119. An optional injection port 120 allows injection of materials or removal of air. A cassette 121 having a moveable piston 122 is used in conjunction with a mechanical actuator 123 of the pump 101. Fluid is pumped into an injection tube 124 from action of the cassette 121 as applied by the actuator 123 of the pump 101. A male luer 126, hydraulically communicating with the catheter supply lumen 114, via the injection tube 124. is configured to attach to the female luer 113 of the y-connector 110.

[0039] Accessories 128 are illustrated that are intended for applying a vacuum source, such as a syringe 130 having a plunger 132 and a barrel 134, to the aspiration lumen 106 of the aspiration catheter 102. The syringe 130 is attached to a vacuum line 136 via the luer 140 of the syringe 130. A stopcock 138 may be used on the luer 140 to maintain the vacuum, or alternatively, the plunger 132 may be a locking variety of plunger that is- Page 5 - Docket No. 22935.49aconfigured to be locked in the retracted (vacuum) position. A male luer 142 at the end of the vacuum line 136 may be detachably secured to the female luer 115 of the y-connector 110 of the aspiration catheter 102. As show n in more detail in Figure 3, a pressure sensor or transducer 144 is secured inside an internal cavity 146 of the y-connector 110 proximal to the female luer 113 and the female luer 115. A valve 150, for example a Touhy -Borst, at the proximal end of the y-connector 110 allows hemostasis of the guidewire lumen / aspiration lumen 106 around a guidewire 148. In other embodiments, the valve 150 may comprise a longitudinally spring-loaded seal. The guidewire 148 may be inserted entirely through the guidewire lumen / aspiration lumen 106. Signals output from the pressure sensor 144 are carried through a cable 152 to a connector 154. The connector 154 is plugged into a socket 156 of the pump 101. Pressure related signals may be processed by a circuit board 158 of the pump 101. The pressure sensor or transducer 144 may be powdered from the pump 101, via the cable 152. The accessories 128 may also be supplied sterile to the user.

[0040] A foot pedal 160 is configured to operate a pinch valve 162 for occluding or opening the vacuum line 136. The foot pedal 160 comprises a base 164 and a pedal 166 and is configured to be placed in a non-sterile area, such as on the floor, under the procedure table / bed. The user steps on the pedal 166 causing a signal to be sent along a cable 168 which is connected via a plug 170 to an input jack 172 in the pump 101. The vacuum line 136 extends through a portion of the pump 101. The circuit board 158 of the pump 101 may include a controller 174 configured to receive one or more signals indicating on or off from the foot pedal 160. The controller 174 of the circuit board 158 may be configured to cause an actuator 176 carried by the pump 101 to move longitudinally to compress and occlude the vacuum line 136 between an actuator head 178 attached to the actuator 176 and an anvil 180, also earned by the pump 101. By stepping on the pedal 166, the user is able to thus occlude the vacuum line 136, stopping the application of a negative pressure. In some embodiments, as the pedal 1 6 of the foot pedal 160 is depressed, the controller may be configured to open the pinch valve 162.

[0041] The pressure sensor or transducer 144 thus senses a negative pressure and sends a signal, causing the controller to start the motor 182 of the pump 101. As the effect via the electronics is substantially immediate, the motor 182 starts pumping almost immediately after the pedal 166 is depressed. As the pedal 166 of the foot pedal 160 is released, the controller 174 then causes the pinch valve 162 to close. The pressure sensor or transducer 144 thus senses that no negative pressure is present and the controller 174- Page 6 - Docket No. 22935.49acauses the motor 182 of the pump 101 to shut off. Again, the effect via the electronics is substantially immediate, and thus the motor 182 stops pumping almost immediately after the pedal 166 is depressed. During sterile procedures, the main interventionalist is usually “scrubbed” such that the hands only touch items in the sterile field. However, the feet / shoes / shoe covers are not in the sterile field. Thus again, a single user may operate a switch (via the pedal 166) while also manipulating the aspiration catheter 102 and guidewire 148. However, this time, it is the sterile field hands and non-stenle field feet that are used. Alternatively, the foot pedal 160 may comprise two pedals, one for occlude and one for open. In an alternative foot pedal embodiment, the pedal 166 may operate a pneumatic line to cause a pressure activated valve or a cuff to occlude and open the vacuum line 136, for example, by forcing the actuator head 178 to move. In another alternative embodiment, the pedal 166 may turn, slide, or otherwise move a mechanical element, such as a flexible pull cable or push rod that is coupled to the actuator 176, to move the actuator head 178. The cable 168 may be supplied sterile and connected to the base 164 prior to a procedure. The occlusion and opening of the vacuum line 136 thus acts as an on and off switch for the pump 101 (via the pressure sensor 144). The on / off function may thus be performed by a user whose hands can focus on manipulating sterile catheters, guidewires, and accessories, and whose foot can turn the pump on and off in anon-sterile environment. This allows a single user to control the entire operation or the majority of operation of the system 100 for aspirating thrombus. This can be an advantage both in terms of a rapid, synchronized procedure, but is also helpful in laboratories where additional assistants are not available. The actuator 176 and anvil 180 may be controlled to compress the vacuum line 136 with a particular force, and the actuator 176 may be controlled to move at a particular speed, either when compressing or when removing compression. Speed and force control allows appropriate response time, but may also be able to add durability to the vacuum line 136, for example, by not over-compressing. The foot pedal 160 may communicate with the pinch valve 162 via a wired connection through the pump 101 or may communicate with the pinch valve 162 wirelessly. Additionally, or alternatively, the pump may be controlled by buttons 184.

[0042] It should be noted that in certain embodiments, the pinch valve 162 and the foot pedal 160 may be incorporated for on / off operation of the pinch valve 162 on the vacuum line 136, without utilizing the pressure sensor 144. In fact, in some embodiments, the pressure sensor 144 may even be absent from the system 100 for aspirating thrombus, the foot pedal 160 being used as a predominant control means.- Page 7 - Docket No. 22935.49a

[0043] Turning to Figure 2, a supply tube 186, which contains the catheter supply lumen 114, freely and coaxially extends within the over- the- wire guidewire lumen / aspiration lumen 106. At least a distal end 185 of the supply tube 186 is secured to an interior wall 190 of the guidewire lumen / aspiration lumen 106 of the catheter shaft 111 by adhesive, epoxy, hot melt, thermal bonding, or other securement modalities. A plug 192 is secured within the catheter supply lumen 114 at the distal end 185 of the supply tube 186. The plug 192 blocks the exit of pressurized fluid, and thus the pressurized fluid is forced to exit through an orifice 194 in the wall 196 of the supply tube 186. The free, coaxial relationship between the supply tube 186 and the catheter shaft 111 along their respective lengths, allows for improved flexibility. In some embodiments, in which a stiffer proximal end of the aspiration catheter 102 is desired (e.g., for pushability or even torqueability), the supply tube 186 may be secured to the interior wall 190 of the guidewire lumen / aspiration lumen 106 of the catheter shaft 111 along a proximal portion of the aspiration catheter 102, but not along a distal portion. This may be appropriate if, for example, the proximal portion of the aspiration catheter 102 is not required to track through tortuous vasculature, but the distal portion is required to track through tortuous vasculature. The free, substantially unconnected, coaxial relationship between the supply tube 186 and the catheter shaft 111 along their respective lengths, may also be utilized to optimize flow through the guidewire lumen / aspiration lumen 106, as the supply tube 186 is capable of moving out of the way due to the forces of flow (e.g., of thrombus / saline) over its external surface, such that the remaining inner luminal space of the guidewire lumen / aspiration lumen 106 self-optimizes, moving toward the lowest energy condition (least fluid resistance) or toward the largest cross-sectional space condition (e.g., for accommodating and passing pieces of thrombus).

[0044] A system 200 for aspirating thrombus is illustrated in Figures 4-5. The system 200 for aspirating thrombus is similar to the system 100 and so the disclosure related to the system 100 is also applicable to the description of system 200. An aspiration catheter 202 is similar to the aspiration catheter 102 of Figures 1-3 and as such the description related to the aspiration catheter 102 of Figures 1-3 is also applicable to the description of the aspiration catheter 202.

[0045] The aspiration catheter 202 is configured for aspirating thrombus from peripheral vessels, but may also be configured with a size for treating coronary, cerebral, pulmonary or other arteries, or veins. The aspiration catheter 202 / system 200 may be used in interventional procedures, but may also be used in surgical procedures. The aspiration- Page 8 - Docket No. 22935.49acatheter 202 / system 200 may be used in vascular procedures, or non-vascular procedures (other body lumens, ducts, or cavities). The catheter 202 comprises an elongate shaft 204 configured for placement within a blood vessel of a subject; a catheter supply lumen 114 (Figure 3) and a guidewire / aspiration lumen 106, each extending along the shaft, the supply lumen 114 having a proximal end 147 and a distal end 185, and the aspiration lumen 106 having a proximal end 145 (Figure 3) and an open distal end 107 (Figure 2); and an orifice or opening 194 at or near the distal end 185 of the supply lumen 114, the opening configured to allow the injection of pressurized fluid into the aspiration lumen 106 at or near the distal end 107 of the aspiration lumen 106 when the pressurized fluid is pumped through the supply lumen 114. In some embodiments, the orifice or opening 194 may be located proximal to the distal end 185 of the supply lumen 114. In some embodiments, the distal end 185 of the supply lumen 114 may comprise a plug 192. A pump set 210 (e.g., tubing set) is configured to hydraulically couple the supply lumen 114 to a pump within a saline drive unit (SDU) 212, for injecting pressurized fluid (e.g., saline, heparinized saline) through the supply lumen 114. Suction tubing 214. comprising sterile suction tubing 216 and non-sterile suction tubing 217, is configured to hydraulically couple a vacuum canister 218 to the aspiration lumen 106. A filter 220 may be carried indine on the suction tubing 214, for example, connected between the sterile suction tubing 216 and the non-sterile suction tubing 217, or on the non-sterile suction tubing 217. The filter 220 is configured to capture large elements such as large pieces of thrombus or emboli.

[0046] The pump set 210 includes a saline spike 221 for connection to a port 222 of a saline bag 224, and an inline drip chamber 226 for visually assessing the movement of saline, as well as keeping air out of the fluid being injected. The saline bag 224 may be hung on an IV pole 227 on one or more hooks 228. A pressure sensor 230 such as a vacuum sensor may be used within any lumen of the pump set 210, the suction tubing 214, the supply lumen 114 or aspiration lumen 106 of the catheter 202, or any other component which may see fluid flow. The pressure sensor 230 is show n in Figure 4 within a lumen at a junction between a first aspiration tube 232 and a control 233. A cable 234 carries signals output from the pressure sensor 230 to a controller 235 in the SDU 212. A connector 236, electrically connected to the cable 234, is configured to be detachably coupled to a mating receptacle 237 (e.g., input jack) in the SDU 212. The SDU 212 also may have a display 238, including an LCD screen or alternative screen or monitor, in order to visually monitor parameters and status of a procedure. In alternative embodiments, the pressure sensor 230- Page 9 - Docket No. 22935.49amay be replaced by another type of sensor that is configured to characterize fluid flow. In some embodiments, the sensor is a flow sensor, such as a Doppler flow velocity sensor.

[0047] The SDU 212 is held on a mount 240 by four locking knobs 242. The mount 240 is secured to a telescoping rod 244 that is adjustable from a cart base 245 via a cart height adjustment knob or other element 246. The mount 240 and a handle 247 are secured to the rod 244 via an inner post 248 that is insertable and securable within an inner cavity in the rod 244. The IV pole 227 secures to the mount 240 via a connector 250. The base 245 may include legs 252 having wheels 253 (e g., three or more wheels or four or more wheels) and may be movable via the handle 247. The system 200 may also cany' a basket 254 for placement of components, products, documentation, or other items.

[0048] In use, a user connects a first connector 256 at a first end 258 of the non-sterile suction tubing 217 to a second port 259 on the lid 260 of the canister 218, and connects a second connector 261 at a second end 262 of the non-sterile suction tubing 217 to a vacuum pump input 264 in the SDU 212. A vacuum pump 266 may be carried within the SDU 212 in order to maintain a vacuum / negative pressure within the canister 218. Alternatively, the vacuum inside the canister 218 may be maintained manually, without a vacuum pump, by evacuating the canister 218 via one or more additional ports 268. A user connects a first connector 270 of the sterile suction tubing 216 to an aspiration luer 271 of the aspiration catheter 202 (similar to luer 115), and connects the second connector 272 of the sterile suction tubing 216 to port 274 in the lid 260 of the canister 218. Connector 236 is then coupled to the mating receptacle 237 in the SDU 212 for communication with the control 233 and / or the pressure sensor 230. For instance, the connector 236 can be snapped into mating receptacle 237 in the SDU 212 for communication with elements of the control 233 and / or for communication with the pressure sensor 230. either via cable 234. and / or additional cables or wires. Alternatively, the connector 236 may couple to the mating receptacle 237 by clipping, friction fitting, vacuum fitting, or other means.

[0049] After allowing saline to purge through the supply tube 276, cassette 278, and injection tube 279 of the pump set 210, the user connects the luer connector 280 of the pump set 210 to a luer 282 of the aspiration catheter 202 (similar to luer 113). The cassette 278 (similar to cassette 121) is then attached to a saddle 283 in the SDU 212. The saddle 283 is configured to reciprocate a piston to inject the saline from the IV bag 224 at high pressure, after the cassette 121 is snapped in place, keeping the internal contents (e.g., saline) sterile. Systems configured for performing this type of sterile injection of high-pressure saline are described in U.S. Pat. No. 9,883,877, issued February 6, 2018, and- Page 10 - Docket No. 22935.49aentitled, “Systems and Methods for Removal of Blood and Thrombotic Material’", which is incorporated by reference in its entirety for all purposes. The SDU 212 is enclosed within a case 284 and a case lid 285. The controller 235 may reside on a circuit board 286. Noise from a motor 287 controlling the saddle 283 and from the vacuum pump 266 is abated by internal foam sections 288, 289. The saddle 283 may be moved directly by the motor 287, or may be moved with pneumatics, using a cycled pressurization. An interface panel 290 provides one or more switches 297 and the display 238. Alternatively, the cassette 121 may couple to the saddle 283 by clipping, friction fitting, vacuum fitting, or other means.

[0050] Figure 5 illustrates aspects pertaining to the vacuum canister 218, in which aspirant (e.g., thrombus, blood, saline) that is evacuated from the patient through the aspiration lumen 106 is collected. The canister 218 may be held in a canister mount 292 carried by the IV pole 227, or alternatively carried by any other part of the system 200. A lid 260 is configured to cover a portion of the canister 218, such as in a snapping manner, to close an interior 296 of the canister 218. Alternatively, the lid 260 may couple to the canister 218 by screwing, clipping, friction fitting, or other means.

[0051] The lid 260 may comprise two or more ports, including the first port 268 and second port 259 for providing negative pressure / vacuum to the aspiration lumen 106. For example, the lid 260 may comprise two ports, three ports, four ports, or more than four ports. Sterile suction tubing 216 may be connected to the lid 260 of the vacuum canister 218 at a first port 268 for transmitting a negative pressure to the sterile suction tubing 216 and to the aspiration lumen 106 of the aspiration catheter 102. Non-sterile suction tubing 217 may be connected to the lid 260 of the vacuum canister 218 at a second port 259 for providing a negative pressure to the vacuum canister 218. A negative pressure may be provided to the non-sterile suction tubing 217 (and to sterile suction tubing 216 and the aspiration lumen 106 connected therewith) by a vacuum source (e.g., a vacuum pump or syringe). The system 200 may also comprise means for sealing the two or more ports of the lid 260 when not in use, such as one or more port caps. A filter may be placed over an entry to the second port 259 so as to prevent aspirant from traveling along the non-sterile suction tubing 217 from the vacuum canister 218 to the vacuum source.

[0052] The vacuum canister 218 preferably has a sufficient volumetric capacity for receiving all aspirant collected during the surgical procedure. Receptacles having a volumetric capacity of approximately 100 cubic inches, or receptacles having a diameter of approximately 5.0 inches and a height of approximately 7.0 inches, have been found to provide sufficient volumetric capacity.- Page 11 - Docket No. 22935.49a

[0053] Returning to Figure 5, a solenoid 298 is carried internally in the SDU 212, and is configured to interface with the interior 296 of the canister 218, via the suction tubing 214, or via any additional tubing. The solenoid 298 is configured to vent the negative pressure inside the canister 218, by opening a valve 299 coupled to the solenoid (mechanically or electromagnetically) that opens the interior 296 of the canister 218 to ambient pressure. The venting allows any foaming of blood or fluid, such as any aspirated liquid, within the canister 218 to be reduced. Foaming can occur during a thrombolysis procedure due to cavitation, as air bubbles are formed. The solenoid 298 is then configured to close the valve 299, to allow negative pressure to again be built up within the interior 296 of the canister 218. The controller 235 is configured to automatically energize the solenoid 298, in order to allow for the degassing / defoaming. For example, the controller 235 may send a signal to energize the solenoid 298 based on the measurement of a targeted negative pressure and / or a targeted time of aspiration cycle. In other cases, the controller 235 can send a signal to energize the solenoid 298 every minute, every five minutes, every ten minutes, etc. Additionally, a user can operate the controller 235, and more generally the controller 174, of the system 200 through the interface panel 290 to initiate degassing / defoaming of the interior 296. The venting may also be able to remove air bubbles inside the other lumens of the catheter and tubing sets.

[0054] In some embodiments, the controller 235 can output or send a signal to energize the solenoid 298 to open the valve 299, in order to stop any aspiration, while still allowing the SDU 212 to deliver saline, medication, or saline combined with medication (e.g., thrombolytic drugs), so that the fluids can be delivered out of the open distal end 107 (instead of being aspirated through the aspiration lumen 106).

[0055] Turning to Figures 6-8 illustrated is another configuration of an aspiration catheter 302 that can be used with the systems 100 or 200 for aspirating thrombus. As such, the discussions related to the aspiration catheter 102 and the aspiration catheter 202 are also applicable to the aspiration catheter 302 illustrated in Figures 6-8.

[0056] As shown in more detail in Figures 6-8, aspiration catheter 302 includes an aspiration lumen 306 formed by a shaft 311, such as a hypotube, jacketed by a polymer jacket or a polymer jacket is laminated on the hypotube. For instance, a shaft body 317a is illustrated being jacket by a jacket 317b. A distal end 305 of the aspiration catheter 302 includes a multilayer structure. A portion 317c of the jacket 317b extends distally of a shaft distal end 325 of the shaft 311 to form part of the distal end 305. An outer layer or outer jacket 317d overlaps the jacket 317b, extends towards and overlaps the distal end- Page 12 - Docket No. 22935.49a325 of the shaft 311, and forms the aspiration catheter distal end 305a or the distal most end of the aspiration catheter with the distal opening 307. The outer jacket 317d protects a distal portion 332 of a supply tube 330 containing a supply lumen 314. While reference is made of a multilayer structure, it will be understood that one or more layers can be omitted or combined together. Additionally, one or more of the layers or shaft body can include braided or other members to increase strength and / or flexibility. Alternatively, the shaft and associated layers can be formed by extruding the shaft or using other structures to form the shaft.

[0057] The supply lumen 314 may be configured to provide a high-pressure fluid injection, such as saline, within the aspiration lumen 306 for macerating a thrombus as it is aspirated, such as illustrated in Figure 8 where the aspiration catheter 302 is disposed within a vessel lumen VL of a vessel V and aspirant A is being drawing into the aspiration lumen 306. The saline injection may occur through orifice 334 near the distal end of the supply lumen 314 if the opening of the supply lumen is plugged with a plug similar to plug 192 (Figure 2). Aspiration catheter 302 may also include a radiopaque (RO) ring 329 at or near the distal end 305 of aspiration catheter 302 for identifying the location of aspiration. The radiopaque ring 329 optionally encircles the aspiration catheter 302. In the illustrated configuration, the RO ring 329 is disposed between the jacket 317b and outer jacket 317d. The RO ring 329 can be formed of any suitable radiopaque material, such as tantalum, tungsten, platinum / iridium, gold, silver, and combinations or modifications thereof.

[0058] The shaft 311 can include one or more openings 327 to increase a flexibility of shaft 311 to aid with advancement of the aspiration catheter 302 through the tortuous anatomy of a patient. While reference is made to a “hypotube,” it will be understood that other tubular structures can be used for the shaft 311. Additionally, the shaft 311 can be formed from polymers, metals, alloys, braided structures, coiled structures, and combinations or modifications thereof. Furthermore, the jacket 317b and outer jacket 317d can be formed of a variety of polymers and copolymers, plastics, PEBAX, HYTREL, rubber, Nylon, polyolefin, fluorinated polymers like FEP or PTFE, polyurethan, polyamides, and combinations or modifications thereof.

[0059] In some situations, during aspiration, damage to the vessel might occur because the vessel wall W is draw n into or against the distal opening 307 of the aspiration lumen 306 and the aspiration catheter distal end 305a may suction onto the vessel wall W, as shown in Figure 9. The aspiration catheter may include a suction mitigation element. As described in more detail below, the suction mitigation element can be configured to- Page 13 - Docket No. 22935.49aprevent the vessel wall from being drawn into or against the distal opening, limit any suction of the vessel wall to the aspiration catheter to non-injurious levels, and / or allow for the release of the suction between the aspiration catheter and the vessel wall if the suction level exceeds a potentially injurious level.

[0060] Figures 10A-22 relate to various example suction mitigation elements, devices, features, means, and methods for limiting or preventing the aspiration catheter from suctioning onto a vessel wall or other body tissue or having the vessel wall or other body tissue being undesirably drawn into the aspiration lumen or against the distal end of the aspiration catheter. The suction mitigation elements, devices, means, and features may also be referred to as suction prevention or suction release elements, devices, means, or features because they can be configured to prevent the distal end of the aspiration catheter from suctioning onto the vessel wall or other body tissue or allow for the release of such suction if it occurs.

[0061] Figures 10A-10B illustrates an example implementation of an aspiration catheter 350. Many of the features and components of the aspiration catheter 350 may be similar or identical to the other aspiration catheters disclosed herein. Accordingly, the discussion of the aspiration catheter 350 will focus on those aspects that are unique thereto.

[0062] As noted above and as shown in Figure 10A, during an aspiration procedure, a vessel wall W or other tissue may be drawn against or into the distal end 352 of the aspiration catheter 350. To limit the amount of suction force that can be applied to the vessel wall W, the aspiration catheter 350 may include a suction mitigation element 354. The suction mitigation element 354 may activate when the suction pressure within the aspiration lumen 356 exceeds a predetermined threshold. Thus, for instance, if a vessel wall W is drawn against or into the distal end 352 of the aspiration catheter 350 as shown in Figure 10A and the suction pressure within the aspiration lumen 356 exceeds the predetermined threshold, the suction mitigation element 354 may activate to reduce the suction pressure with the aspiration lumen 356 as show n in Figure 10B. With the activation of the suction mitigation element 354 and the reduction in the suction pressure within the aspiration lumen 356, the suction pressure that is drawing the vessel wall W against or into the distal end 352 of the aspiration catheter 350 may be reduced to a level that will not draw the vessel w all W against or into the distal end 352 of the aspiration catheter 350 or at least not with enough force to injure the vessel wall W.

[0063] The suction mitigation element 354 may take a variety of forms. For instance, the suction mitigation element 354 may be a valve in the wall of the aspiration catheter- Page 14 - Docket No. 22935.49a350. The valve may be configured to open upon the application of the predetermined threshold suction pressure within the aspiration lumen 356. In the embodiment illustrated in Figures 10A-10B, the suction mitigation element 354 valve may include one or more release cuts or scores 358 in the wall of the aspiration catheter 350. The release cuts or scores 358 may be incisions formed partially through the wall of the aspiration catheter 350, thereby creating a weakened portion of the wall of the aspiration catheter 350. The portion of the catheter wall that includes the release cuts or scores 358 may be strong enough to withstand normal operating conditions. However, if the suction pressure within the aspiration lumen 356 exceeds the predetermined threshold, the release cuts or scores 358 may extend all the way through the catheter wall, thereby creating an opening 360 in the catheter wall as shown in Figure 10B. The opening 360 may allow for fluids surrounding the aspiration catheter 350 to flow into the aspiration lumen 356, thereby reducing the suction pressure at the opening in the distal end 352 of the aspiration catheter 350. The reduced pressure at the distal end 352 of the aspiration catheter 350 may prevent injury to the vessel wall W and / or release the vessel wall W from being suctioned to the aspiration catheter 350.

[0064] While Figures 10A and 10B illustrate the suction mitigation element 354 as a valve with one or more release cuts or scores 358, it will be appreciated that this ty pe of valve is merely exemplary. Any other suitable type of valve may be included in the wall of the aspiration catheter 350.

[0065] While the aspiration catheter 350 may include a suction mitigation element 354, such as a valve, that may selectively open when a predetermined threshold pressure is reached, a suction mitigation element 354 may include other types of features. Figures 11-23 illustrate various example embodiments of other suction mitigation elements 354.

[0066] Figure 11 illustrates the distal end 362 of an aspiration catheter 364. The aspiration catheter 364 may be similar or identical in many respects to the other aspiration catheters disclosed herein. As can be seen, the distal end is angled such that a first portion 366a of the distal end 362 extends further distally than a second portion 366b thereof. The angled portion of the distal end 362 may’ have one or more contours. For instance, in some embodiments, then angled portion may lie within a single plane. In other embodiments, the angled portion may have portions that are angled relative to one another and lie within different planes. In any event, the angled portion may reduce the likelihood of a vessel wall W or other body tissue from being drawn into or suctioned against the distal end 362 of the aspiration catheter 364. For instance, the angled portion or the contours thereof may- Page 15 - Docket No. 22935.49areduce the likelihood of the vessel wall W fully covering the distal opening 368 and thereby becoming suctioned thereto.

[0067] In addition to the angled portion of the distal end 362, the aspiration catheter 364 may also include one or more windows or openings 370 in a wall thereof. In the illustrated embodiment, the window or opening 370 is positioned distal to the proximal-most portion of the distal opening 368. The windows or openings 370 may allow for fluids surrounding the aspiration catheter 364 to flow into the aspiration catheter 364 to reduce the suction pressure within. Because of the ability of fluid to flow through the windows or openings 370, the likelihood of a vessel wall W becoming suctioned to the distal opening 368 is further reduced. Additionally, even if a vessel wall W does become suctioned to the distal opening 368, the suction force applied to the vessel wall W will be limited to levels that are unlikely to cause damage to the vessel wall W.

[0068] Figure 12 illustrates another embodiment of an aspiration catheter 372 that may be similar or identical in many respects to the aspiration catheter 364 of Figure 11. The primary difference between the aspiration catheters 364. 372 is the placement of the window or opening 374 in the wall of the aspiration catheter 372. In the illustrated embodiment, the window or opening 374 is positioned proximal to the proximal-most portion of the distal opening 376. Despite the different placement, the window or opening 374 may limit the suction pressure on the vessel wall W.

[0069] While Figures 11 and 12 illustrate windows or openings in specific locations, these placements are merely exemplary. An aspiration catheter may include one or more windows in any number of locations in the wall of the catheter.

[0070] Figure 13 illustrates an aspiration catheter 378 that may be similar or identical in many respects to the other aspiration catheters disclosed herein. In the illustrated embodiment, the aspiration catheter 378 includes a shaft 380 and a distal end 382. In the illustrated embodiment, the shaft 380 has a first outer dimension and the distal end 382 has a second outer dimension that is larger than the first outer dimension. The second outer dimension of the distal end 382 may be similar in size to an inner dimension of a vessel or other body lumen or may be selectively expandable so as to be similar in size to an inner dimension of a vessel or other body lumen. Sizing the distal end 382 to be similar to the inner dimension of a vessel or other body lumen and / or enable for expansion of the distal end accordingly may help to center the distal end 382 within the vessel or other body lumen and prevent the vessel or lumen wall from being drawn into or against a distal opening in the distal end 382. In some embodiments where the distal end 382 is expandable, the distal- Page 16 - Docket No. 22935.49aend 382 include a braided structure that facilitates the selective expansion and contraction thereof. In some embodiments, the braided structure may be formed of a Nitinol or other shape memory material. In still other embodiments, an actuator (e.g., a pull wire) may be connected to the distal end 382 and configured to be pulled on by a user to expand the distal end 382.

[0071] Additionally, the distal end 382 may include one or more windows, openings, or vent ports 384. The windows, openings, or vent ports 384 may be disposed circumferentially about all or a portion of the distal end 382 and may have rectangular, circular, oval, or other shapes. The windows, openings, or vent ports 384 may function similar to the windows or openings 370, 374 discussed above. In some embodiments, the windows, opening, or vent ports 384 may be angled or contoured to increase a distance that blood or other bodily fluid would have to travel in order to enter the aspiration catheter 378 and escape from the body therethrough.

[0072] Figure 14 illustrates an aspiration catheter 386 that may be similar or identical in many respects to the other aspiration catheters disclosed herein. In the illustrated embodiment, the aspiration catheter 386 includes a shaft 388 and a distal end 390. In the illustrated embodiment, the shaft 388 has a first outer dimension and the distal end 390 has a second outer dimension that is larger than the first outer dimension. The second outer dimension of the distal end 390 may be similar in size to an inner dimension of a vessel or other body lumen. As with the aspiration catheter 378, the distal end 390 may be selectively expandable and collapsible. The distal end 390 may have curved outer contours or edges. The curves / contours and the sizing the distal end 390 to be similar to the inner dimension of a vessel or other body lumen may help to center the distal end 390 within the vessel or other body lumen and prevent the vessel or lumen wall from being drawn into or against a distal opening in the distal end 390.

[0073] Additionally, the distal end 390 may include one or more windows, openings, or vent ports 392. The windows, openings, or vent ports 392 may be disposed circumferentially about all or a portion of the distal end 390 and may have rectangular, circular, oval, or other shapes. The windows, openings, or vent ports 390 may function similar to the windows, openings, vent ports 370, 374, 384 discussed above.

[0074] Figure 15 illustrates an aspiration catheter 394 that may be similar or identical in many respects to the other aspiration catheters disclosed herein. In the illustrated embodiment, the aspiration catheter 394 includes a shaft 396 and a distal end 398. In the illustrated embodiment, the shaft 396 has a first outer dimension and at least a portion of- Page 17 - Docket No. 22935.49athe distal end 398 has a second outer dimension that is larger than the first outer dimension. The distal end 398 may be selectively expandable and collapsible to facilitate insertion thereof into the body lumen and removable of thrombotic material. The distal end 398 may have a tapered or contoured outer surface. A proximal portion of the tapered or contoured outer surface may include the second dimension while a distal portion thereof may have an outer dimension that that is smaller than the second dimension.

[0075] Additionally, the tapered or contoured outer surface may include one or more grooves or slits 400. The grooves or slits 400 may extend partially or all of the way through the wall of the distal end 398. In some embodiments, the grooves or slits are rectangular in shape, while in other embodiments, the grooves or slits may have circular, semi-circular, oval, or scallop shapes. In any event, the grooves or slits 400 may allow for the flow of fluid therethrough and / or around the distal end 398 and into an aspiration lumen in the aspiration catheter 394. This flow of fluid may reduce a suction pressure within the aspiration catheter 394 to levels that are unlikely to injure the body tissue.

[0076] Figure 16 illustrates an aspiration catheter 410 that may be similar or identical in many respects to the other aspiration catheters disclosed herein. In the illustrated embodiment, the aspiration catheter 410 includes a shaft 412 with a distal end 414. The outer surface of the distal end 414 may be coated with a highly lubricious coating 416 that is configured to prevent the distal end 414 from forming a suction seal with a vessel wall. For instance, the outer surface of the distal end 414 may be coated with a hydrophobic or hydrophilic material or may have a polymer jacket disposed therearound. The highly lubricious coating 416 may allow the distal end 414 to slide against the surface of the vessel wall sufficiently to prevent the distal end 414 from suctioning onto the vessel wall.

[0077] Figures 17A and 17B illustrate an aspiration catheter 418 that may be similar or identical in many respects to the other aspiration catheters disclosed herein. In the illustrated embodiment, the aspiration catheter 418 includes a shaft 420 with an opening in a distal end 422 thereof. The aspiration catheter 418 also includes one or more suction mitigation elements 424. In the illustrated embodiment, the one or more suction mitigation elements 424 include one or more shape memory wires. The one or more shape memory wires may be formed of Nitinol or another suitable shape memory material.

[0078] The one or more shape memory wires may be movable between a retracted position as shown in Figure 17A and a deployed position as shown in Figure 17B. In the retracted position, the one or more shape memory wires, including the distal ends 428 thereof, may be disposed within an aspiration lumen 426 within the shaft 420 or in one or- Page 18 - Docket No. 22935.49amore other lumens in the shaft 420, as show n in Figure 17 A. The shaft 420 may maintain the shape memory wires in generally straight configurations within the shaft 420 when in the retracted position.

[0079] In contrast, when the shape memory wires are moved to the deployed position as shown in Figure 17B, the distal ends 428 thereof may extend out of the distal end 422 of the shaft 420. When the distal ends 428 of the wires extend out of the shaft 420, the shaft 420 no longer maintains the distal ends 428 of the shape memory wires in the generally straight configurations. Rather, the distal ends 428 of the shape memory wires may move or bend to their memory’ shape. In the illustrated embodiment, the distal ends 428 of the shape memory' wires bend back towards the outside of the shaft 420. As a result, the outer dimension of the distal end of the aspiration catheter 418 is increased. The increased outer dimension can help to center the distal end of the aspiration catheter 418 within the vessel or body lumen, which can help prevent the aspiration catheter 418 from suctioning onto the wall of the vessel or body lumen. Additionally, the contours and / or spacing between the shape memory wires may also help prevent the aspiration catheter 418 from suctioning on to the wall of the vessel or body lumen. For instance, the contours and / or spacing betw een the wires may create or maintain gaps between the distal end 422 and the wall of the vessel or body lumen, which may prevent the creation of a suction seal therebetween.

[0080] Figures 18A and 18B illustrate an aspiration catheter 430 that may be similar or identical in many respects to the other aspiration catheters disclosed herein. In the illustrated embodiment, the aspiration catheter 430 includes a shaft 432 with an opening in a distal end 434 thereof. The aspiration catheter 430 also includes one or more suction mitigation elements 436. In the illustrated embodiment, the one or more suction mitigation elements 436 include one or more deployable tips. The one or more deployable tips may be formed of Nitinol or another suitable flexible material.

[0081] The one or more deployable tips may be movable between a retracted position as shown in Figure 18A and a deployed position as shown in Figure 18B. In the retracted position, the one or more deployable tips, including a distal end 438 thereof, may be disposed within an aspiration lumen 440 within the shaft 432 or in one or more other lumens in the shaft 432, as shown in Figure 18 A. In contrast, when the one or more deployable tips are moved to the deployed position as shown in Figure 18B, the distal ends 438 thereof may extend out of the distal end 434 of the shaft 432. When the distal ends 438 of the one or more deployable tips extend out the distal end 434 of the shaft 432, the- Page 19 - Docket No. 22935.49aone or more deploy able tips may engage with the wall of a vessel or other body lumen and create a gap between the wall and the distal end 434 of the shaft 432, which may prevent the creation of a suction seal therebetween.

[0082] Similar to the embodiment of Figures 18A-18B, Figure 19 illustrates an embodiment of an aspiration catheter 442 that includes a shaft 444 and a suction mitigation element 446. The suction mitigation element 446 may include one or more deployable tips that can be selectively extended out from a distal end 448 of the shaft 444. Unlike the deployable tips of Figures 18A-18B that extend generally straight, the one or more deploy able tips of Figure 19 may extend out in a non-linear manner. For instance, the one or more deployable tips may be formed from a shape memory' material such as Nitinol. Once deployed from the shaft 444, the shape memory material may return to its memory shape, which may include one or more curves, bends, and / or straight segments. The one or more deployable tips may also be formed from polymers, metals, alloys (e.g., MP35), or other suitable materials. When the one or more deploy able tips extend out of the distal end 448 of the shaft 444, the one or more deployable tips may engage with the wall of a vessel or other body lumen and create a gap between the wall and the distal end 448 of the shaft 444, which may prevent the creation of a suction seal therebetween.

[0083] Figure 20 illustrates an aspiration catheter 450 that may be similar or identical in many respects to the other aspiration catheters disclosed herein. In the illustrated embodiment, the aspiration catheter 450 includes a shaft 452 with an opening in a distal end 454 thereof. The aspiration catheter 450 also includes one or more suction mitigation elements 456 at the distal end 454 of the shaft 452. In the illustrated embodiment, the one or more suction mitigation elements 456 include one or more deployable anchors. The one or more deployable anchors may be formed of Nitinol, a polymer, or another suitable flexible material.

[0084] The one or more deployable anchors may be movable between a retracted position and a deployed position (show n in Figure 20). In the retracted position, the one or more deployable anchors may be disposed within the shaft 452 or substantially flat against the outer surface thereof such that they will not inhibit movement of the distal end 454 through a body lumen or injure body tissue. In contrast, when the one or more deploy able anchors are moved to the deployed position as shown in Figure 20, they may extend radially out of the distal end 454 of the shaft 452. When the one or more deployable anchors extend out from shaft 452, the anchors may engage the wall of a vessel or other body lumen and center the distal end 454 within the vessel or body lumen, thereby- Page 20 - Docket No. 22935.49apreventing the creation of a suction seal between the distal end 454 and the wall of the vessel or body lumen. The one or more deploy able anchors may be formed of materials (e.g., Nitinol) that are flexible enough to avoid injuring the wall of the vessel or body lumen. The one or more deploy able anchors may have contours that allow for the anchors to engage the wall of the vessel or body lumen to hold the distal end 454 in place, but without injuring the wall of the vessel or body lume.

[0085] The suction mitigation elements of Figures 17A-20 may be connected to a suitable actuator that allows for the selective deployment and retraction of the suction mitigation elements. For instance, the suction mitigation elements may be connected to a trigger, button, or lever on a handle operated by a user. The connection between the trigger, button, or lever and the suction mitigation elements may be by way of a cable, wire, or other mechanical element. Activation of the trigger, button, or lever may selectively deploy the suction mitigation element prior to aspiration and may retract the suction mitigation element after completion of the aspiration and prior to removal of the aspiration catheter from the vessel or body lumen.

[0086] Figure 21 illustrates an aspiration catheter 458 that may be similar or identical in many respects to the other aspiration catheters disclosed herein. In the illustrated embodiment, the aspiration catheter 458 includes a shaft 460 with a distal end 462 thereof. The aspiration catheter 458 also includes one or more suction mitigation elements 464 at the distal end 462 of the shaft 460. In the illustrated embodiment, the one or more suction mitigation elements 464 include one or more rings or bumpers that extend circumferentially around the distal end 462. The one or more rings or bumpers may be formed from Nitinol, a polymer, a balloon, or other suitable material.

[0087] The one or more rings or bumpers may be movable between a retracted position and a deployed position (shown in Figure 21). In the retracted position, the one or more deployable anchors may be disposed within the shaft 460 or substantially flat against the outer surface thereof. In contrast, when the one or more rings or bumpers are moved to the deployed position as shown in Figure 21, they may extend radially out of the distal end 462 of the shaft 460. When the one or more rings or bumpers extend out from shaft 460, the rings or bumpers may engage the wall of a vessel or other body lumen and center the distal end 462 within the vessel or body lumen, thereby preventing the creation of a suction seal between the distal end 462 and the wall of the vessel or body lumen.

[0088] When the one or more rings or bumpers are formed from a shape memory material, such as Nitinol, the rings or bumpers may be held close against the outer surface- Page 21 - Docket No. 22935.49aof the shaft 460 by a sheath. After placement of the aspiration catheter 458, the sheath may be withdrawn and the shape memory material may return to its memory’ shape, which may have a larger outer dimension that enables the ring or bumper to engage the wall of the vessel or body lumen. After completion of the procedure, the sheath may be passed over the ring or bumper to return it to a smaller outer dimension and allow for removal of the aspiration catheter from the vessel or body lumen.

[0089] In cases where the ring or bumper is formed of a balloon, the balloon may be in fluid communication with an inflation lumen. Fluid may' be selectively delivered to the balloon to inflate it when the aspiration catheter 458 is positioned as desired within a vessel or body lumen. Similarly, after completion of the procedure, the fluid may be withdrawn from the balloon through the inflation lumen, thereby allowing the ballon to return to it uninflated configuration and for removal of the aspiration catheter 458 from the vessel or body lumen.

[0090] Figure 22 illustrates a distal end 470 of an aspiration catheter 472. In the illustrated embodiment, the distal end 470 includes a suction mitigation element in the form of surface texturing 474. The surface texturing 474 may be formed using lasers, 3D printing, stamping, etching, or the like. The surface texturing 474 may create grooves or channels that reduce the potential for a wall of a vessel or other body lumen from being suctioned onto the distal end 470 of the aspiration catheter 472.

[0091] Figure 23 illustrates an aspiration catheter 476 that may be similar or identical in many' respects to the other aspiration catheters disclosed herein. In the illustrated embodiment, the aspiration catheter 476 includes a shaft 478 with a distal end 480 thereof. The aspiration catheter 476 also includes a suction mitigation element in the form of a radially extending curve 482 in the wall of the shaft 478 adjacent to the distal end 480. In some embodiments, the curve 482 may be a permanent feature of the shaft 478. In other embodiments, the curve 482 may be selectively formed. For instance, when the aspiration catheter 476 is being inserted through a vessel or body lumen, the cun e 482 may be retracted such that the shaft 478 has a generally consistent outer dimension. Once the aspiration catheter 476 is placed as desired, the curve 482 may be deployed. The deployed curve 482 may engage the wall of the vessel or body lumen and help center the distal end 480 therein, which can limit or prevent the wall of the vessel or body lumen from being suctioned on the distal end 480.

[0092] The curve 482 may be moved between the retracted and deployed configurations in any suitable manner. For instance, a distal portion of the curve 482 may- Page 22 - Docket No. 22935.49abe connected to a wire or cable that extends proximally to a user handle. Upon retraction of the wire or cable, the distal end 480 of the shaft 478 may move proximally relative to the length of the shaft 478, thereby causing the curve 482 to expand radially.

[0093] Although the systems for aspirating thrombus described herein are predominantly focused on aspiration, the systems may also, or alternatively, be configured for injecting or infusing fluids, with or without drugs, and may incorporate related features described in U.S. Pat. No. 10,716,583, issued July 21, 2020, and entitled, ‘‘Systems and Methods for Removal of Blood and Thrombotic Material” and U.S. Pat. No. 10,492,805, issued December 3, 2019, and entitled, “Systems and Methods for Thrombosis and Delivery of an Agent.”

[0094] It is contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments disclosed above may be made and still fall within one or more of the embodiments. Further, the disclosure herein of any particular feature, aspect, method, property, characteristic, quality7, attribute, element, or the like in connection with an embodiment can be used in all other embodiments set forth herein. Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form vary ing modes of the disclosed embodiments. Thus, it is intended that the scope of the present disclosure herein disclosed should not be limited by the particular disclosed embodiments described above. Moreover, while the present disclosure is susceptible to various modifications, and alternative forms, specific examples thereof have been shown in the drawings and are herein described in detail. It should be understood, however, that the present disclosure is not to be limited to the particular forms or methods disclosed, but to the contrary, the present disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the various embodiments described and the appended claims. Any methods disclosed herein need not be performed in the order recited. The methods disclosed herein include certain actions taken by a practitioner; however, they can also include any third-party instruction of those actions, either expressly or by implication.

[0095] The ranges disclosed herein also encompass any and all overlap, sub-ranges, and combinations thereof. Uanguage such as “up to,” “at least,” “greater than,” “less than,” “between,” and the like includes the number recited. Numbers preceded by a term such as “approximately”, “about”, and “substantially” as used herein include the recited numbers (e.g., about 10%=l 0%), and also represent an amount close to the stated amount that still- Page 23 - Docket No. 22935.49aperforms a desired function or achieves a desired result. For example, the terms ‘“approximately”, “about”, and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of the stated amount.

[0096] For purposes of the present disclosure and appended claims, the conjunction “or” is to be construed inclusively (e.g., “an apple or an orange” would be interpreted as “an apple, or an orange, or both”; e.g., “an apple, an orange, or an avocado” would be interpreted as “an apple, or an orange, or an avocado, or any two, or all three”), unless: (i) it is explicitly stated otherwise, e.g., by use of “either... or,” “only one of,” or similar language; or (ii) two or more of the listed alternatives are mutually exclusive within the particular context, in which case “or” would encompass only those combinations involving non-mutually-exclusive alternatives. For purposes of the present disclosure and appended claims, the words “comprising,” “including,” “having,” and variants thereof, wherever they appear, shall be construed as open-ended terminology, with the same meaning as if the phrase “at least” were appended after each instance thereof.

[0097] Following are some further example embodiments of the invention. These are presented only by way of example and are not intended to limit the scope of the invention in any way. Further, any example embodiment can be combined with one or more of the example embodiments.

[0098] Embodiment 1. An aspiration system comprising: an elongate shaft configured for placement within a blood vessel, the elongate shaft having a distal end and an aspiration lumen extending therethrough; and a suction mitigation element disposed at or adjacent to the distal end of the elongate shaft, the suction mitigation element being configured to limit or prevent a wall of the blood vessel from being drawn into the aspiration lumen or being suctioned onto the distal end of the elongate shaft.

[0099] Embodiment 2. The aspiration system of embodiment 1, wherein the suction mitigation element comprises a valve is a wall of the elongate shaft, the valve being configured to selectively open when a suction pressure within the aspiration lumen exceeds a predetermined threshold.

[0100] Embodiment 3. The aspiration system of embodiment 1 or 2, wherein the suction mitigation element comprises an angled end or face of the distal end of the elongated shaft.- Page 24 - Docket No. 22935.49a

[0101] Embodiment 4. The aspiration system of any of embodiments 1-3, wherein the distal end comprises an outer dimension that is larger than an outer dimension of a length of the elongated shaft.

[0102] Embodiment 5. The aspiration system of any of embodiments 1-4, wherein the suction mitigation element comprises one or more grooves or slits therein.

[0103] Embodiment 6. The aspiration system of any of embodiments 1-5, wherein the suction mitigation element comprises a lubricious coating on an outer surface of the distal end.

[0104] Embodiment 7. The aspiration system of any of embodiments 1-6, wherein the suction mitigation element comprises one or more shape memory wires.

[0105] Embodiment 8. The aspiration system of any of embodiments 1-7, wherein the suction mitigation element comprises one or more deployable anchors.

[0106] Embodiment 9. The aspiration system of any of embodiments 1-8, wherein the suction mitigation element comprises one or more rings or bumpers.

[0107] Embodiment 10. The aspiration system of any of embodiments 1-9, wherein the suction mitigation element comprises one or more surface textures on the distal end of the elongated shaft.

[0108] Embodiment 11. The aspiration system of any of embodiments 1-10, wherein the suction mitigation element comprises a selectively deploy able curve in or adjacent to the distal end of the elongated shaft.

[0109] Embodiment 12. An aspiration system comprising: an elongate shaft configured for placement within a blood vessel, the elongate shaft having a distal end and an aspiration lumen extending therethrough; and a suction mitigation element disposed at or adjacent to the distal end of the elongate shaft, the suction mitigation element being configured to limit or prevent a wall of the blood vessel from being drawn into the aspiration lumen or being suctioned onto the distal end of the elongate shaft, wherein the suction mitigation element comprises a valve is a wall of the elongate shaft, the valve being configured to selectively open when a suction pressure within the aspiration lumen exceeds a predetermined threshold.

[0110] Embodiment 13. The aspiration system of embodiment 12, wherein the valve comprises one or more release cuts or scores formed in the wall of the elongated shaft.

[0111] Embodiment 14. An aspiration system comprising: an elongate shaft configured for placement within a blood vessel, the elongate shaft having a distal end and an aspiration lumen extending therethrough; and a suction mitigation element disposed at- Page 25 - Docket No. 22935.49aor adjacent to the distal end of the elongate shaft, the suction mitigation element being configured to limit or prevent a wall of the blood vessel from being drawn into the aspiration lumen or being suctioned onto the distal end of the elongate shaft, wherein the suction mitigation element comprises an angled end or face of the distal end of the elongated shaft.

[0112] Embodiment 15. The aspiration system of embodiment 14, wherein the angled end or face lies within a single plane.

[0113] Embodiment 16. The aspiration system of embodiment 14, wherein the angled end or face lies within multiple planes.

[0114] Embodiment 17. The aspiration system of any of embodiments 14-16, wherein the suction mitigation element further comprises a window or opening through a wall of the elongate shaft.

[0115] Embodiment 18. The aspiration system of embodiment 17, wherein the window or opening is positioned proximal to the angled end or face.

[0116] Embodiment 19. The aspiration system of embodiment 17, wherein the window or opening is disposed distal from at least a portion of the angled end or face.

[0117] Embodiment 20. An aspiration system comprising: an elongate shaft configured for placement within a blood vessel, the elongate shaft having a distal end and an aspiration lumen extending therethrough; and a suction mitigation element disposed at or adjacent to the distal end of the elongate shaft, the suction mitigation element being configured to limit or prevent a wall of the blood vessel from being drawn into the aspiration lumen or being suctioned onto the distal end of the elongate shaft, wherein the distal end comprises an outer dimension that is larger than an outer dimension of a length of the elongated shaft.

[0118] Embodiment 21. The aspiration system of embodiment 20, wherein the distal end further comprises one or more windows, openings, or vent ports extending between an outer surface of the distal end and the aspiration lumen.

[0119] Embodiment 22. The aspiration system of embodiment 20 or 21, wherein the distal end comprises a curved or rounded outer shape.

[0120] Embodiment 23. An aspiration system comprising: an elongate shaft configured for placement within a blood vessel, the elongate shaft having a distal end and an aspiration lumen extending therethrough; and a suction mitigation element disposed at or adjacent to the distal end of the elongate shaft, the suction mitigation element being configured to limit or prevent a wall of the blood vessel from being drawn into the- Page 26 - Docket No. 22935.49aaspiration lumen or being suctioned onto the distal end of the elongate shaft, wherein the suction mitigation element comprises one or more grooves or slits formed in an outer surface of the distal end.

[0121] Embodiment 24. The aspiration system of embodiment 23, wherein the one or more grooves or slits are formed in an outer surface of the distal end.

[0122] Embodiment 25. The aspiration system of embodiment 23 or 24, wherein the one or more grooves or slits extend through the distal end between an outer surface thereof and the aspiration lumen.

[0123] Embodiment 26. An aspiration system comprising: an elongate shaft configured for placement within a blood vessel, the elongate shaft having a distal end and an aspiration lumen extending therethrough; and a suction mitigation element disposed at or adjacent to the distal end of the elongate shaft, the suction mitigation element being configured to limit or prevent a wall of the blood vessel from being drawn into the aspiration lumen or being suctioned onto the distal end of the elongate shaft, wherein the suction mitigation element comprises a lubricious coating on an outer surface of the distal end.

[0124] Embodiment 27. The aspiration system of embodiment 26, wherein the lubricious coating comprises a hydrophobic or hydrophilic material or a polymer jacket.

[0125] Embodiment 28. An aspiration system comprising: an elongate shaft configured for placement within a blood vessel, the elongate shaft having a distal end and an aspiration lumen extending therethrough; and a suction mitigation element disposed at or adjacent to the distal end of the elongate shaft, the suction mitigation element being configured to limit or prevent a wall of the blood vessel from being draw n into the aspiration lumen or being suctioned onto the distal end of the elongate shaft, wherein the suction mitigation element comprises one or more shape memory wires.

[0126] Embodiment 29. The aspiration system of embodiment 28, wherein the one or more shape memory wires are configured to selectively move between a retracted position within the elongate shaft to an extended position at least partially outside of the distal end.

[0127] Embodiment 30. The aspiration system of embodiment 28 or 29, wherein the one or more shape memory wires are configured to bend back over the distal end and tow ards an outer surface thereof.

[0128] Embodiment 31. An aspiration system comprising: an elongate shaft configured for placement within a blood vessel, the elongate shaft having a distal end and an aspiration lumen extending therethrough; and a suction mitigation element disposed at- Page 27 - Docket No. 22935.49aor adjacent to the distal end of the elongate shaft, the suction mitigation element being configured to limit or prevent a wall of the blood vessel from being drawn into the aspiration lumen or being suctioned onto the distal end of the elongate shaft, wherein the suction mitigation element comprises one or more deployable tips.

[0129] Embodiment 32. The aspiration system of embodiment 31, wherein the one or more deployable tips are configured to selectively move between a retracted position within the elongate shaft to an extended position at least partially outside of the distal end.

[0130] Embodiment 33. The aspiration system of embodiment 31 or 32, wherein the one or more deployable tips are configured to extend linearly from the distal end of the elongated shaft.

[0131] Embodiment 34. The aspiration system of any of embodiments 31-33, wherein the one or more deployable tips are configured to extend from the distal end of the elongated shaft and comprise one or more bends or curves when deployed.

[0132] Embodiment 35. The aspiration system of any of embodiments 31-34, where in the one or more deploy able tips are formed from a shape memory material.

[0133] Embodiment 36. An aspiration system comprising: an elongate shaft configured for placement within a blood vessel, the elongate shaft having a distal end and an aspiration lumen extending therethrough; and a suction mitigation element disposed at or adjacent to the distal end of the elongate shaft, the suction mitigation element being configured to limit or prevent a wall of the blood vessel from being drawn into the aspiration lumen or being suctioned onto the distal end of the elongate shaft, wherein the suction mitigation element comprises one or more deployable anchors.

[0134] Embodiment 37. The aspiration system of embodiment 36, wherein the one or more deployable anchors are configured to be selectively moved between a retracted position and a deployed position.

[0135] Embodiment 38. An aspiration system comprising: an elongate shaft configured for placement within a blood vessel, the elongate shaft having a distal end and an aspiration lumen extending therethrough; and a suction mitigation element disposed at or adjacent to the distal end of the elongate shaft, the suction mitigation element being configured to limit or prevent a wall of the blood vessel from being drawn into the aspiration lumen or being suctioned onto the distal end of the elongate shaft, wherein the suction mitigation element comprises one or more rings or bumpers.- Page 28 - Docket No. 22935.49a

[0136] Embodiment 39. The aspiration system of embodiment 38, wherein the one or more rings or bumpers extend at least partially around a circumference of the distal end of the elongated shaft.

[0137] Embodiment 40. The aspiration system of embodiment 38 or 39, wherein the one or more rings or bumpers are formed of a shape memory7material that is configured to be moved between a retracted position and a deployed position.

[0138] Embodiment 41. The aspiration system of embodiment 40, wherein the suction mitigation element further comprises a sheath that is configured to selectively hold the shape memory7material in the retracted position and is configured for selective removal to enable the shape memory material to expand to the deployed position.

[0139] Embodiment 42. The aspiration system of any of embodiments 38-41, wherein the one or more rings or bumpers extend in a spiral around the distal end of the elongated shaft.

[0140] Embodiment 43. The aspiration sy stem of any of embodiments 38-42, wherein the one or more rings or bumpers comprise a balloon that is configured for selective inflation and deflation.

[0141] The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.- Page 29 - Docket No. 22935.49a

Claims

CLAIMS1. An aspiration system comprising:an elongate shaft configured for placement within a blood vessel, the elongate shaft having a distal end and an aspiration lumen extending therethrough; anda suction mitigation element disposed at or adjacent to the distal end of the elongate shaft, the suction mitigation element being configured to limit or prevent a wall of the blood vessel from being drawn into the aspiration lumen or being suctioned onto the distal end of the elongate shaft.

2. The aspiration system of claim 1 , wherein the suction mitigation element comprises a valve is a wall of the elongate shaft, the valve being configured to selectively open when a suction pressure within the aspiration lumen exceeds a predetermined threshold.

3. The aspiration system of claim 1 or 2, wherein the suction mitigation element comprises an angled end or face of the distal end of the elongated shaft.

4. The aspiration system of any of claims 1-3, wherein the distal end comprises an outer dimension that is larger than an outer dimension of a length of the elongated shaft.

5. The aspiration system of any of claims 1-4, wherein the suction mitigation element comprises one or more grooves or slits therein.

6. The aspiration system of any of claims 1-5, wherein the suction mitigation element comprises a lubricious coating on an outer surface of the distal end.

7. The aspiration system of any of claims 1 -6, wherein the suction mitigation element comprises one or more shape memory' wires.

8. The aspiration system of any of claims 1-7, wherein the suction mitigation element comprises one or more deployable anchors.

9. The aspiration system of any of claims 1-8, wherein the suction mitigation element comprises one or more rings or bumpers.

10. The aspiration system of any of claims 1-9, wherein the suction mitigation element comprises one or more surface textures on the distal end of the elongated shaft.

11. The aspiration system of any of claims 1-10, wherein the suction mitigation element comprises a selectively deployable curve in or adjacent to the distal end of the elongated shaft.

12. An aspiration system comprising:an elongate shaft configured for placement within a blood vessel, the elongate shaft having a distal end and an aspiration lumen extending therethrough; and- Page 30 - Docket No. 22935.49aa suction mitigation element disposed at or adjacent to the distal end of the elongate shaft, the suction mitigation element being configured to limit or prevent a wall of the blood vessel from being drawn into the aspiration lumen or being suctioned onto the distal end of the elongate shaft, wherein the suction mitigation element comprises a valve is a wall of the elongate shaft, the valve being configured to selectively open when a suction pressure within the aspiration lumen exceeds a predetermined threshold.

13. The aspiration system of claim 12, wherein the valve comprises one or more release cuts or scores formed in the wall of the elongated shaft.

14. An aspiration system comprising:an elongate shaft configured for placement within a blood vessel, the elongate shaft having a distal end and an aspiration lumen extending therethrough; anda suction mitigation element disposed at or adjacent to the distal end of the elongate shaft, the suction mitigation element being configured to limit or prevent a wall of the blood vessel from being drawn into the aspiration lumen or being suctioned onto the distal end of the elongate shaft, wherein the suction mitigation element comprises an angled end or face of the distal end of the elongated shaft.

15. The aspiration system of claim 14, wherein the angled end or face lies within a single plane.

16. The aspiration system of claim 14, wherein the angled end or face lies within multiple planes.

17. The aspiration system of any of claims 14-16, wherein the suction mitigation element further comprises a window or opening through a wall of the elongate shaft.

18. The aspiration system of claim 17, wherein the window or opening is positioned proximal to the angled end or face.

19. The aspiration system of claim 17, wherein the window or opening is disposed distal from at least a portion of the angled end or face.

20. An aspiration system comprising:an elongate shaft configured for placement within a blood vessel, the elongate shaft having a distal end and an aspiration lumen extending therethrough; anda suction mitigation element disposed at or adjacent to the distal end of the elongate shaft, the suction mitigation element being configured to limit or prevent a wall of the blood vessel from being drawn into the aspiration lumen or being suctioned onto the distal end of the elongate shaft, wherein the distal end comprises an outer dimension that is larger than an outer dimension of a length of the elongated shaft.- Page 31 - Docket No. 22935.49a21. The aspiration system of claim 20, wherein the distal end further comprises one or more windows, openings, or vent ports extending between an outer surface of the distal end and the aspiration lumen.

22. The aspiration system of claim 20 or 21, wherein the distal end comprises a curved or rounded outer shape.

23. An aspiration system comprising:an elongate shaft configured for placement within a blood vessel, the elongate shaft having a distal end and an aspiration lumen extending therethrough; anda suction mitigation element disposed at or adjacent to the distal end of the elongate shaft, the suction mitigation element being configured to limit or prevent a wall of the blood vessel from being drawn into the aspiration lumen or being suctioned onto the distal end of the elongate shaft, wherein the suction mitigation element comprises one or more grooves or slits formed in an outer surface of the distal end.

24. The aspiration system of claim 23, wherein the one or more grooves or slits are formed in an outer surface of the distal end.

25. The aspiration system of claim 23 or 24, wherein the one or more grooves or slits extend through the distal end between an outer surface thereof and the aspiration lumen.

26. An aspiration system comprising:an elongate shaft configured for placement within a blood vessel, the elongate shaft having a distal end and an aspiration lumen extending therethrough; anda suction mitigation element disposed at or adjacent to the distal end of the elongate shaft, the suction mitigation element being configured to limit or prevent a wall of the blood vessel from being drawn into the aspiration lumen or being suctioned onto the distal end of the elongate shaft, wherein the suction mitigation element comprises a lubricious coating on an outer surface of the distal end.

27. The aspiration system of claim 26, wherein the lubricious coating comprises a hydrophobic or hydrophilic material or a polymer jacket.

28. An aspiration system comprising:an elongate shaft configured for placement within a blood vessel, the elongate shaft having a distal end and an aspiration lumen extending therethrough; anda suction mitigation element disposed at or adjacent to the distal end of the elongate shaft, the suction mitigation element being configured to limit or prevent a wall of the blood vessel from being drawn into the aspiration lumen or being suctioned onto the distal- Page 32 - Docket No. 22935.49aend of the elongate shaft, wherein the suction mitigation element comprises one or more shape memory wires.

29. The aspiration system of claim 28, wherein the one or more shape memory wires are configured to selectively move between a retracted position within the elongate shaft to an extended position at least partially outside of the distal end.

30. The aspiration system of claim 28 or 29, wherein the one or more shape memory wires are configured to bend back over the distal end and towards an outer surface thereof.

31. An aspiration system comprising:an elongate shaft configured for placement within a blood vessel, the elongate shaft having a distal end and an aspiration lumen extending therethrough; anda suction mitigation element disposed at or adjacent to the distal end of the elongate shaft, the suction mitigation element being configured to limit or prevent a wall of the blood vessel from being draw n into the aspiration lumen or being suctioned onto the distal end of the elongate shaft, w herein the suction mitigation element comprises one or more deploy able tips.

32. The aspiration system of claim 31, wherein the one or more deployable tips are configured to selectively move betw een a retracted position within the elongate shaft to an extended position at least partially outside of the distal end.

33. The aspiration system of claim 31 or 32, wherein the one or more deployable tips are configured to extend linearly from the distal end of the elongated shaft.

34. The aspiration system of any of claims 31-33, w herein the one or more deploy able tips are configured to extend from the distal end of the elongated shaft and comprise one or more bends or curves when deployed.

35. The aspiration system of any of claims 31 -34, where in the one or more deploy able tips are formed from a shape memory material.

36. An aspiration system comprising:an elongate shaft configured for placement within a blood vessel, the elongate shaft having a distal end and an aspiration lumen extending therethrough; anda suction mitigation element disposed at or adjacent to the distal end of the elongate shaft, the suction mitigation element being configured to limit or prevent a wall of the blood vessel from being draw n into the aspiration lumen or being suctioned onto the distal end of the elongate shaft, wherein the suction mitigation element comprises one or more deployable anchors.- Page 33 - Docket No. 22935.49a37. The aspiration system of claim 36, wherein the one or more deployable anchors are configured to be selectively moved between a retracted position and a deployed position.

38. An aspiration system comprising:an elongate shaft configured for placement within a blood vessel, the elongate shaft having a distal end and an aspiration lumen extending therethrough; anda suction mitigation element disposed at or adjacent to the distal end of the elongate shaft, the suction mitigation element being configured to limit or prevent a wall of the blood vessel from being drawn into the aspiration lumen or being suctioned onto the distal end of the elongate shaft, wherein the suction mitigation element comprises one or more rings or bumpers.

39. The aspiration system of claim 38, wherein the one or more rings or bumpers extend at least partially around a circumference of the distal end of the elongated shaft.

40. The aspiration system of claim 38 or 39, wherein the one or more rings or bumpers are formed of a shape memory material that is configured to be moved between a retracted position and a deployed position.

41. The aspiration system of claim 40, wherein the suction mitigation element further comprises a sheath that is configured to selectively hold the shape memory7material in the retracted position and is configured for selective removal to enable the shape memory7material to expand to the deployed position.

42. The aspiration system of any of claims 38-41. wherein the one or more rings or bumpers extend in a spiral around the distal end of the elongated shaft.

43. The aspiration system of any of claims 38-42, wherein the one or more rings or bumpers comprise a balloon that is configured for selective inflation and deflation.- Page 34 - Docket No. 22935.49a

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