Aspiration with impedance-based sensing

Abstract

Aspiration with impedance-based sensing may be provided by a catheter system, including: a catheter, including: a catheter body having a proximal end, a distal end, and a lumen therebetween; and an electrode, including a first contact and a second contact located at the distal end of the catheter; and an impedance measuring device, in electrical communication with the first contact and the second contact.

Description

Attorney Docket No.: 1956788.00447Client Docket No.: 2023-209-PCTTITLEASPIRATION WITH IMPEDANCE-BASED SENSINGCROSS-REFERENCES TO RELATED DISCLOSURES

[0001] The present disclosure The present disclosure claims priority to U.S. Provisional Patent Application 63 / 724,747, filed on 2024-11-24, titled “ASPIRATION WITH IMPEDANCEBASED SENSING”, which is incorporated herein in its entirety to the extent permissible by law.BACKGROUND

[0002] When aspirating bodily fluids and any solids carried therewith (e.g., embolisms in blood), an aspiration catheter is used, which can draw significant quantities of collateral bodily fluid in addition to the solids, damage the surrounding tissue, or take longer than optimal if negative pressure applied by the aspiration catheter is applied sub-optimally. When encountering an embolism, clot, or other obstruction in a biological lumen, the negative pressure exerted by the aspiration catheter may change due to partial blockages by the obstructions, reduced fluid in the biological lumen (e.g., due to the obstruction damming the biological lumen), partial collapse of the biological lumen, and other undesired effects and combinations thereof. Accordingly, applying the optimal pressure throughout an aspiration operation can often be challenging, which affects the speed and efficacy of the operations.SUMMARY

[0003] The present disclosure provides systems and methods for aspiration with impedance based sensing. An aspiration catheter is provided with electrodes to identify an impedance of a material contacted by the catheter, which is used to determine when an obstruction has been reached and identify the type of obstruction contacted by the catheter. As different obstructions exhibit different impedances, these data are provided to a negative pressure source (e.g., a vacuum pump) which automatically adjusts a pressure duty cycle to a pattern designed to remove the corresponding type of obstruction while reducing stress on the biological lumen in which the obstruction is disposed.1508264568.1Attorney Docket No.: 1956788.00447Client Docket No.: 2023-209-PCT

[0004] Additional features and advantages of the disclosed method and apparatus are described in, and will be apparent from, the following Detailed Description and the Figures. The features and advantages described herein are not all-inclusive and, in particular, many additional features and advantages will be apparent to one of ordinary skill in the art in view of the figures and description. Moreover, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and not to limit the scope of the inventive subject matter.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 illustrates an example aspiration operation, according to embodiments of the present disclosure.

[0006] Figures 2A-2D illustrate detailed views of an example catheter with integrated impedance sensors, according to embodiments of the present disclosure.

[0007] Figures 3A and 3B illustrate example wiring of a catheter with integrated impedance sensors, according to embodiments of the present disclosure.

[0008] Figures 4A-4C illustrate example impedance charts, according to embodiments of the present disclosure.

[0009] Figure 5 is a flowchart for an example method of aspiration using impedance-based sensing, according to embodiments of the present disclosure.

[0010] Figure 6 illustrates a computing device, according to embodiments of the present disclosure.DETAILED DESCRIPTION

[0011] The present disclosure provides for aspiration with impedance-based sensing, in which an aspiration catheter equipped with two or more electrical contacts (e.g., electrodes) disposed on the distal tip provides impedance measurements for identifying when the catheter contacts a clot or other obstruction, and how and when to best apply negative pressure to aspirate that clot to reduce fluid loss. Despite significant advances in endovascular thrombectomy technology, the first-pass rate is still low, and a large percentage of procedures require two or more retrieval attempts, sometimes using different devices. However, identifying the composition of the clot (via the devices and methodologies described herein) provides critical insight into the most effective2508264568.1Attorney Docket No. : 1956788.00447Client Docket No.: 2023-209-PCT patient-specific treatment approaches so that a patient-specific treatment strategy can be selected for the specific type of clot encountered. Accordingly, technologies of the present disclosure helps to reduce repeat maneuvers, such as switching between different devices during the procedure, the time needed to perform the procedure, and the risk of performing repeated maneuvers thereby improving the first-pass rate and treatment efficacy among other benefits that will become apparent on a detailed review of the present disclosure.

[0012] In contrast to devices that only include impedance sensing on a guidewire or internal portion of a catheter, the present disclosure allows the use of a catheter as a single device for exploration and aspiration which provides real-time measurements during the aspiration procedure; allowing for the automatic adjustment of aspiration settings during the procedure based on changing aspects of the clot to be aspirated. As used herein, the term “automatic”, “automatically” and variations thereof are to be understood to refer to operations that are performed by a machine, computer, or combination thereof without input or instruction from a human.

[0013] In some embodiments, the control of the aspiration settings is managed via a machine learning model or profile for specific types of clots. The machine learning model and real-time impedance measurements allow the negative pressure source to alter the magnitude of pressure and duration of application of pressure with fully closed feedback loop to improve the chances of aspirating a clot. Additionally, data including clot type, impedance value, time to aspirate, etc. may be collected and automatically uploaded to a database, which allows for further training of the machine learning model to automatically select or predict the pressure application profile with the highest success rate associated with a given type of clot.

[0014] Although different embodiments and examples may be described herein, the present disclosure contemplates that any of the features from different embodiments or examples can be combined together in different permutations than shown or discussed in the exemplary figures. Stated differently, the features of different embodiments may be freely mixed and matched with one another. Accordingly, although every permutation of features is not explicitly shown, the present disclosure contemplates that such permutations are possible, and are to be included within the inventive concepts described herein.

[0015] Figure 1 illustrates an example aspiration operation 100, according to embodiments of the present disclosure. As shown, an obstruction 120 is located in a biological lumen 110, and a3508264568.1Attorney Docket No. : 1956788.00447Client Docket No.: 2023-209-PCT catheter 130 has been inserted into the biological lumen 110 to remove the obstruction 120 via aspiration. In various embodiments, the biological lumen 110 may be a blood vessel, ureter, urethra, bile duct, or other lumen or cavity in a biological subject. In various embodiments, the obstruction 120 may be a foreign body, a blood clot, plaque, stone or other solidification of a bodily fluid or mineral carried therein, or the like that fully or partially occludes the biological lumen 110.

[0016] The catheter 130 is inserted into the biological lumen 110 and is in fluid communication with a pressure source 150 (such as a vacuum pump as a negative pressure source) that applies a negative pressure to draw the obstruction 120 (fully or when broken in parts) into the catheter 130 and out of the biological subject. Additionally, the catheter 130 is in electrical communication with an impedance measuring device 140. Although illustrated as separate devices, in various embodiments, the negative pressure source 1 0 and the impedance measuring device 140 may be combined or integrated into a single device.

[0017] Although the examples given herein are primarily discussed in relation to measuring impedance, in various embodiments, other sensors may be disposed in the catheter 130 or the pressure source 150, such as fluid flowrate sensors, pressure sensors, temperature sensors, voltage sensors, current sensors, or the like. The data collected by these sensors may be used to augment the impedance-based measurements that are discussed herein.

[0018] In some embodiments, a server or database 170 is in communication with one or both of the impedance measuring device 140 and the pressure source 150 via network 180. In some embodiments, the server / database 170, may be locally maintained, or a cloud-based server / database 170, that is accessible by multiple parties. The server / database 170 is configured to configured to process impedance data and negative pressure data in in real-time. In some embodiments, the server / database 170 includes a machine learning model that is configured to process the impedance data in real-time and used to select / predict a pressure application profile based on the impedance data reported by the impedance measuring device 140 to control how the pressure source 150 is applied to remove the obstruction 120.

[0019] Additionally, an optional fluoroscope 160 is illustrated, which may be used to identify where the catheter 130 is located in the biological subject to help an operator guide the catheter 130 to where the obstruction 120 is located. One of the requisite skill in the art will be familiar with the operation and use of a fluoroscope 160 in conjunction with an aspiration catheter 130.4508264568.1Attorney Docket No. : 1956788.00447Client Docket No.: 2023-209-PCTThe fluoroscope 160 includes an x-ray or other high energy radio source and a fluorescent or other viewing screen on opposing sides of the biological subject, and projects high energy waves through the biological subject, which are blocked to varying degrees by biological tissues to produce varying levels of brightness on the viewing screen as may be interpreted by an operator to identify the location of internal aspects of the biological subject. As will be appreciated, the fluoroscopy process initially produces a negative image, but the viewing screen may apply various logical (software) instructions to re-color or highlight certain elements identified in the image.

[0020] As used herein, various elements may be described as “radio-opaque”, which refers to the property of the element to block some or all of the waves from the radio source of a fluoroscope so that the element appears more vividly on the viewing screen than bodily tissue. As will be understood, both the size and the density of the element affect whether the element consistently exhibits a radio opaque property, as the rays used by the radio source may not strike an object that is thin enough due to the wavelength of the ray. For example, platinum, gold, silver, titanium, and other metals and alloys thereof may be sufficiently dense to block x-rays, but when spun into wires, the wires may be sufficiently thin that x-rays do not reliably strike those wires, and the wires may not generally be considered radio opaque. One of ordinary skill in the art will be able to determine if an object is radio opaque for a given energy and wavelength of radio source.

[0021] Figures 2A-2D illustrate detailed views 200a, 200b, and 200c, of an example catheter 130 with integrated impedance sensors, according to embodiments of the present disclosure. Figure 2A illustrates a catheter 130 having a two-part electrode 210 mounted on a distal end 220 of the catheter 130 (e.g., the entryway for aspiration) and Figure 2B illustrates a sectional view of the catheter 130 of Figure 2A. Figure 2C illustrates a catheter 130 having a four-part electrode 210 mounted on a distal end 220 of the catheter 130 (e.g., the entryway for aspiration). Figure 2D illustrates a sectional view of a catheter 130 including internal and external electrodes 210. The catheter 130 includes an internal structure (discussed in greater detail in regard to Figures 3A and 3B) that supports a shell 230 having an outer surface 232 and an inner surface 234, generally defining a tubular cross-section with an internal lumen 240. In various embodiments, the internal lumen 240 may be used to deliver objects from a proximal end 250 of the catheter 130 that is disposed outside of the biological subject toward the distal end 220, or draw objects located at the distal end 220 towards the proximal end 250 (e.g., aspirating an obstruction 120).5508264568.1Attorney Docket No. : 1956788.00447Client Docket No.: 2023-209-PCT

[0022] As used herein, the distal end 220 refers to a portion of a catheter 130 that is inserted into the biological lumen 110, and includes the distal tip 225 through which the opening of the lumen 240 is formed. In various embodiments the distal end 220 refers to the portion of the catheter 130 comprising the final 50 mm, 100 mm, 150 mm, or 200 mm of the catheter 130. The distal end 220 is opposite to the proximal end 250, which remains outside of the biological subject and available for a practitioner to interact with.

[0023] In various embodiments, the shell 230 is made of a flexible polymeric material generally having a low coefficient of friction (for ease of insertion into and removal from the biological lumen 110), and is generally non-conductive to electricity. In various embodiments, the shell 230 is made in several distinct layers, which may include the same or different materials than the other layers, any may include various components disposed between those layers. For example, the materials used in the various layers may include, but are not limited to: polytetrafluoroethylene (PTFE), polyolefine elastomers, linear low density polyethylene (LLDPE), low density polyethylene (LDPE), Nylon, Pebax, and the like.

[0024] As shown in Figure 2A, the two-part electrode 210 is dimensioned and constructed of an appropriate electrically conductive material have two electrical contacts 212a-b (generally or collectively, contacts 212) that are both electrically conductive and radio-opaque. Accordingly, the electrode 210 may serve as (and replace) a fluoroscopic radio marker at the distal end 220 of the catheter 130. To allow for easy identification via fluoroscopy, the contacts 212 have a depth 260 defined along the longitudinal axis for the catheter 130 greater than a surface area in the endplane of the catheter 130. For example, an 8-French catheter 130 may have an end plane with an outer diameter of 24 millimeters (mm), and a contact with a depth 260 of 50- 150 mm, a first portion of which is exposed from the body of the catheter 130 and a second portion of which is embedded (e g., not exposed) from the body of the catheter 130.

[0025] Although illustrated as being disposed in a plane perpendicular to the longitudinal axis of the catheter 130, in various embodiments, the electrical contacts 212 may be disposed in planes that are non-perpendicular (e.g., between 15 and 45 degrees to perpendicular) to the longitudinal axis.

[0026] Each contact 212 of the electrode 210 is generally the same shape as the other contact 212, albeit mirrored. Each contact 212 is in separate electrical communication with the impedance measuring device 140 (e g., via separate wires, as disused in greater detail in relation to Figures6508264568.1Attorney Docket No. : 1956788.00447Client Docket No.: 2023-209-PCT3 A and 3B), which allows the impedance measuring device 140 to measure an impedance across the contacts 212. As will be appreciated, impedance includes resistive and reactive components, and is measured via the application of an alternating current (AC) signal to one contact 212, which is transmitted through an intervening medium (e.g., an obstruction 120) to the other contact 212, and the difference between the transmitted and received AC signals is used to determine the impedance of the intervening medium.

[0027] Although illustrated in Figures 2A-2D with particular shapes of the contacts 212, various other shapes that conform to, extend from, or project around, the catheter 130 and relative sizes thereof are contemplated.

[0028] As further shown in Figure 2A, the electrode 210 is mounted to a tip surface 236 of the shell 230, and is held in place via connections to the conductive wires or structures within the shell 230, pressure mounts to the shell 230, or combinations thereof. Although illustrated with a smaller diameter than the catheter 130 (e.g., leaving a portion of the tip surface 236 inward and outward from a longitudinal axis of the catheter 130 exposed), in various embodiments, the dimensions of the electrode 210 may be such that the electrode 210 projects to one or more of the edges of the tip surface 236, which may help secure the electrode 210 in place. Additionally, in some embodiments, the electrode 210 may project rearward around the tip surface 236 onto one or both of the outer surface 232 and inner surface 234 of the catheter 130.

[0029] As shown in Figure 2B, the electrode 210 is included in the shell 230, and a portion of the electrode is exposed from the shell 230 by the removal (or lack of initial construction) of a portion of the tip surface 236. The remaining portion of the tip surface 236 helps retain the electrode 210, and provides a smooth surface with a low coefficient of friction, and potential buffer at the distal end 220 in front of and around the electrode 210 (e.g., to avoid or reduce the risk of accidental contact with the walls of the biological lumen 110).

[0030] As shown in Figure 2C, the electrode 210 is illustrated as a four-part electrode 210, which includes four electrical contacts 212a-d. Including the four electrical contacts 212 may provide various advantages over designs that include two electrical contacts 212, such as allowing for selective pairing of contacts which are disposed in different positions around a longitudinal axis of the catheter 130 in order to measure impedance across a longer distance two-part electrode designs, or with greater resolution / fidelity for where impedances are circumferentially measured.7508264568.1Attorney Docket No. : 1956788.00447Client Docket No.: 2023-209-PCT

[0031] As shown in Figure 2D, the electrode 210 may include portions that are exposed from or mounted to the distal tip of the catheter 130, as well as portions that are exposed within the internal lumen 240 of the catheter 130. As shown for the first and second contacts 212a-b, an electrode 210 may be exposed both from the distal tip and within the internal lumen 240, or may only be exposed internally, as the third and fourth contacts 212c-d demonstrate. The electrode 210 exposed from an internal wall or the catheter 130 (e.g., defining the internal lumen 240) may provide confirmation of internal capture of an obstruction or other substance (e.g., blood, mucus, pus) being aspirated via the catheter 130 at various portions along the longitudinal length of the catheter 130 in the distal end 220 or towards the proximal end 250.

[0032] The present disclosure also contemplates that one or more of the electrical contacts 212 may be replaced with correspondingly shaped insulative sections for two or more of the electrical contacts 212 (e.g., resulting in a two-part design with a similar appearance to the four-part design). For example, electrical contact 212b and electrical contact 212c may be replaced with electrically insulative material, thereby resulting in a two-electrical-contact design similar to that depicted in Figure 2A, but with the electrical contact 212a spaced further apart from the electrical contact 212d in Figure 2C than from the electrical contact 212b in Figure 2A.

[0033] The present disclosure also contemplates that any embodiment of the present disclosure may fdl gaps between the electrical contacts 212 with electrically insulative material, thereby forming a complete ring of material circumferentially disposed around the longitudinal axis of the catheter 130. Such embodiments may include portions of the ring which are electrically conductive (e g., the electrical contacts 212) and portions of the ring which are electrically insulative (e.g., electrically insulative material in lieu of gaps between the electrodes 210).

[0034] Additionally, although illustrated with two electrical contacts 212a-b (e.g., as in Figure 2A) and four electrical contacts 212a-d (e.g., as in Figure 2C), the present disclosure contemplates that three electrical contacts 212 or more than four electrical contacts 212 may also be provided, thereby allowing for selective control of which contacts 212 are active at a given time to measure impendences therebetween with various resolutions in the biological lumen.

[0035] Figures 3 A and 3B illustrate example wiring 300 of a catheter 130 with integrated impedance sensors, according to embodiments of the present disclosure. Figure 3A illustrates a catheter 130 having integrated conductors 320a-b (generally or collectively, conductors 320) with the structural supports 310 of the catheter 130, and Figure 3B illustrates conductors 320 threaded8508264568.1Attorney Docket No. : 1956788.00447Client Docket No.: 2023-209-PCT separately from the structural supports 310 of the catheter 130. In various embodiments, the supports 310 and the conductors 320 may be made from wires, braided sets of wires, etched components (e.g., from tube stock with various portions removed via chemical or laser etching), or additively manufactured components (e.g., via a base material and a three-dimensional printing process). These conductors 320 may be in communication with the electrical contacts 212 to provide the integrated impedance sensors for the catheter 130.

[0036] As shown in Figure 3 A, the integrated conductors 320 may also serve as structural supports 310, and are braided with the same pitch as the other structural supports 310 and are woven among one another. In various embodiments, the conductors 320 may include an insulator layer to prevent electrical communication with the structural supports 310, or may be disposed in a different layer (e.g., of a different radius) from the structural support 310. Although illustrated with two conductors 320a, the present disclosure contemplates that the number of conductors 320 matches the numbers of contacts 212, and each contact 212 is associated with a corresponding conductor 320 to permit individual selection of contacts 212 by which to measure impedance.

[0037] The structural supports 310 provide a support structure according to a given braiding pattern (e.g., as catheter braids) that use various wire materials, wire diameter, pitches (coil densities in a given length of the catheter 130) to affect the stiffness of the catheter 130 at various points. Generally, using a high coil density, larger wire diameter, and harder materials results in a stiffer catheter 130. In various embodiments, the support structure uses structural supports with a shore hardness of 25A, 45A, or 45A.

[0038] Because catheters 130 are used to access and help treat interior locations within a biological subject, the catheter 130 is designed to be both flexible (to navigate tortuous passageways in various vessels without damage thereto) and pushable (to allow an operator to move the catheter 130 forward without bunching, kinking, or otherwise damaging the catheter 130). Accordingly, the supports 310 disposed within the shell 230 of the catheter 130 provide a balance of rigidity / pushability and flexibility to the catheter 130 to impart the desired characteristics to navigate the biological lumen 110. Gaps disposed radially between the electrical contacts 212 also allow for greater deformability of the catheter 130; allowing compression and expansion of the tip of the catheter 130 during navigation. Similarly, the presence of the electrical contacts 212 provides greater rigidity at the tip; thereby improve the pushability and reduce the likelihood of the tip being pushed in to the lumen of the catheter 130.9508264568.1Attorney Docket No. : 1956788.00447Client Docket No.: 2023-209-PCT

[0039] In various embodiments, the stiffness / flexibility of the catheter 130 is imparted, at least in part, based on the size, shape, and location of the supports 310 in the shell 230. In various embodiments, the supports 310 include a single coil of a stiffening material, a helix of multiple coils (that do not contact one another) of a stiffening material, a braid of multiple coils (that do contact one another) of a stiffening material, or a mesh of a predefined pattern of a stiffening material. When using multiple structural supports 310, different supports 310 may be placed at different layers within the shell 230 to electrically isolate the supports 310 from one another, be spaced apart in the same layer to electrically isolate the supports 310 from one another.

[0040] The rigidity imparted by the supports 310 on the catheter 130 may be controlled by the spacing of individual coils of the supports 310 (e.g., a larger spacing increases flexibility), by changing the diameter of the wire / material (e.g., a smaller diameter increases flexibility), or by using a material of certain softness in forming the supports 310. For example, the supports 310 may be formed from a nitinol wire, which is relatively soft, or a stainless-steel wire, which is relatively stiffer than the nitinol wire. Various example of stiffening materials for use in the supports 310 include, but are not limited to: nickel, iron, titanium copper, aluminum, tin, zinc, gold, silver, platinum, and various alloys thereof (e.g., bronze, nitinol, steel), or the like. Additionally or alternatively, the supports 310 may be made of stiffening materials such as those used in the fabrication of the shell 230.

[0041] When at least two supports 310 that are electrically isolated from one another are included in the catheter 130, and the material used for these supports 310 is electrically conductive, these isolated and conductive structures may also be used as the conductors 320 for the catheter 130. The supports 310 used as integrated conductors 320 are placed into electrical communication with one corresponding contact 212, and with a corresponding lead 330 that is in electrical communication with the impedance measuring device 140.

[0042] Additionally or alternatively to using the stiffening supports 310 as integrated conductors 320, separate conductors 320 may be included in the catheter 130 that are in electrical communication with one corresponding contact 212, and with a corresponding lead 330 that is in electrical communication with the impedance measuring device 140. These separate conductors 320 may be insulated from the supports 310 by being disposed in a separate layer of the shell 230 than the supports 310 or by being disposed in an interstitial space in the supports 310 in a given layer. Similarly, the conductors 320 may be insulated from one another by being disposed in10508264568.1Attorney Docket No. : 1956788.00447Client Docket No.: 2023-209-PCT separate layers of the shell 230 from one another or by being disposed in the interstitial spaces in a given layer from one another (e.g., in a double helix).

[0043] Although generally discussed as coils of wire that wound around the longitudinal axis of catheter 130, in various embodiments, the supports 310 and conductors 320 may include various straightened or bunched features to allow for stretching (e.g., due to physical or thermal expansion) and bending at predefined sections of the catheter 130.

[0044] Figures 4A-4C illustrate example impedance charts 400a-c (generally or collectively impedance charts 400), according to embodiments of the present disclosure. When measuring the impedance of the media contacted by the electrode 210 of the catheter 130 described herein, various readings indicate contact with different materials. For example, when the contacts 212 touch an obstruction 120 of a blood clot, the measured values for impedance will vary depending on the composition of the clot, as blood, soft clots, and hard clots all have different natural impedance values. These values may also change over time, as the obstruction 120 is aspirated and begins to break up (increasing blood flow), shift in the biological lumen 110 (e.g., increasing or decreasing occlusion), and exposed different portions of the obstruction 120 to the contacts 212 (e g., clots with varying hardnesses). Accordingly, the catheter 130 allows for the real-time and continuous collection of impedance data from inside of the biological subject.

[0045] Figure 4A shows individual impedance measurements taken with an alternating current (AC) used for impedance measurement at 1 kilohertz (kHz) for a first clot type 41 Oa-f, and a second clot type 420a-f, and blood 430a-f without a clot or other obstruction. Similarly, Figures 4B and 4C show individual impedance measurements for a first clot type 410, and a second clot type 420 and blood 430, but with an AC measurements occurring at 10 kHz and 100 kHz, respectively. In each of Figures 4A-4C, the impedance values for the six individual measurements of each medium (e g., clot type 1, clot type 2, blood) provide differentiable impedance values from one another, allowing for an impedance analyzer to identify a type of clot or other obstruction (or the lack thereof) based on an observed impedance.

[0046] Table 1 provides additional details on the values shown in Figure 4A.

[0047] Table 111508264568.1Attorney Docket No. : 1956788.00447Client Docket No.: 2023-209-PCT

[0048] Table 2 provides additional details on the values shown in Figure 4B.

[0049] Table 2

[0050] Table 3 provides additional details on the values shown in Figure 4C.

[0051] Table 312508264568.1Attorney Docket No. : 1956788.00447Client Docket No.: 2023-209-PCT

[0052] Figure 5 is a flowchart of an example method 500 of aspiration using impedance-based sensing, according to embodiments of the present disclosure. Method 500 begins at block 510, where an operator inserts a catheter 130 into a biological lumen 110. In various embodiments, the operator guides the catheter 130 to a target site using a fluoroscope to see where a tip of the catheter 130 is located relative to the biological subject, and may also use impedance measurements (as per block 520) to identify when a target location has been reached.

[0053] At block 520, the impedance measuring device 140 measures an impedance at the tip of the catheter 130. In various embodiments, the impedance measuring device 140 applies an AC signal via one contact at the tip of the catheter 130 to be measured by the a second contact at the tip of the catheter 130 to determine the impedance measurement of any substance or media across the two contacts, such a blood, mucus, a wall of the biological lumen 110, or an obstruction 120 caught in the biological lumen 110. In various embodiments, the AC signal may vary in frequency at different times (e.g., measuring impedance at time ti at frequency fi, at time t2 at frequency fz, etc.) and may vary in magnitude at different times (e.g., measuring impedance at time ti at amplitude ai, at time t2 at amplitude a2, etc.), and may vary in waveform at different times (e.g., measuring impedance at time ti via a sine wave, at time t2 via a sawtooth wave, at time t3 via a square wave, etc.). Accordingly, an operator may select different combinations of frequency, amplitude, and waveform at different time to measure different aspects of impedance per block 520.

[0054] At block 530, the impedance measuring device 140 transmits the measured impedance (per block 520) to the negative pressure source. In various embodiments, the impedance measuring device 140 may be integrated with the negative pressure source in a single device, or connected via a wired or wireless transmission medium with the negative pressure source. The negative pressure source may be a vacuum pump with associated controller, and the impedance measuring device may be an LCR meter, an impedance meter, an impedance analyzer, or the like.

[0055] At block 540, the negative pressure source determines a pressure profile to apply based on the measured impedance. In various embodiments, the pressure profile sets one or more of a number of duty cycles or time to apply the selected pressures, a frequency at which to cycle between pressuremax and a pressuremin, an amplitude window (e.g., values for pressuremax and pressuremin), a ramp or wave type (e.g., sinusoidal, triangular, sawtooth, square, etc.), and combinations thereof. In various embodiments, as the impedance measured at the tip of the catheter13508264568.1Attorney Docket No. : 1956788.00447Client Docket No.: 2023-209-PCT130 changes during aspiration (e.g., due to changes in the composition of the obstruction at different points of the obstruction, the break-up or removal of the obstruction, etc.), the negative pressure source may adjust or select a different the pressure profile to continue aspiration with parameters matched to the currently observed impedance characteristics.

[0056] The selection of a given pressure profile from a plurality of pressure profiles is based on the impedance values that are learned to be associated with different types of clots and other obstructions. Accordingly, as obstructions with different physical properties that affect how to best remove the obstruction, and these physical properties translate into different observable impedances, the observed impedance may be used to identify the physical properties of the obstruction and how the obstruction will react to aspiration. In various embodiments, different profiles may be developed for different ranges of impendences, operator preferences, and combinations thereof. For example, operators may have preferences where faster removal is better than slower removal, removal of less bodily fluid is better than more removal of more bodily fluid, more complete removal of the obstruction is better than partial removal of the obstruction, and various combinations thereof, which different profiles may provide for a given observed impedance / structure for an obstruction.

[0057] In various embodiments, the various pressure profiles may be developed and adjusted via a machine learning model, which can incorporate operational data a results feedback from one or more controllers. In various embodiments, these data are amalgamated via a cloud or a centralized service from several operators, and the developed profiles are distributed based on the operational feedback from a plurality of geographically dispersed operators. For example when a first operator identifies that a given combination of duty cycle, pressure amplitude, and ramp type provides improved removal for an obstruction that exhibits a given impedance, this combination may be shared with other operators or used to update a profile that the machine learning model creates to use or suggest when a subsequent obstruction with a similar impedance is identified.

[0058] At block 550, the operator aspirates the obstructions according to the selected pressure profile (per block 540). Method 500 may conclude upon the successful aspiration of the obstruction, or return to block 520 from block 550 for continued measurement and adjustment / selection of pressure profiles during aspiration of the obstruction. In various embodiments, the pressure profile may be applied per block 550 for at least a threshold duration before selecting a different pressure profile or ceasing aspiration, to allow for the suction of the14508264568.1Attorney Docket No.: 1956788.00447Client Docket No.: 2023-209-PCT obstruction through the catheter 130 (e.g., inward from the tip to a collection device), transient changes in impedance (e.g., due to temporary loss of contact at the tip with the obstruction, minor changes in the composition of the obstruction, etc.), to allow for completion of a duty cycle, and combinations thereof.

[0059] Figure 6 illustrates a computing device 600, as may be used as a controller in the impedance measuring device or negative pressure source, according to embodiments of the present disclosure. The computing device 600 may include at least one processor 610, a memory 620, and a communication interface 630.

[0060] The processor 610 may be any processing unit capable of performing the operations and procedures described in the present disclosure. In various embodiments, the processor 610 can represent a single processor, multiple processors, a processor with multiple cores, and combinations thereof.

[0061] The memory 620 is an apparatus that may be either volatile or non-volatile memory and may include RAM, flash, cache, disk drives, and other computer readable memory storage devices. Although shown as a single entity, the memory 620 may be divided into different memory storage elements such as RAM and one or more hard disk drives. As used herein, the memory 620 is an example of a device that includes computer-readable storage media, and is not to be interpreted as transmission media or signals per se.

[0062] As shown, the memory 620 includes various instructions that are executable by the processor 610 to provide an operating system 622 to manage various features of the computing device 600 and one or more programs 624 to provide various functionalities to users of the computing device 600, which include one or more of the features and functionalities described in the present disclosure. One of ordinary skill in the relevant art will recognize that different approaches can be taken in selecting or designing a program 624 to perform the operations described herein, including choice of programming language, the operating system 622 used by the computing device 600, and the architecture of the processor 610 and memory 620. Accordingly, the person of ordinary skill in the relevant art will be able to select or design an appropriate program 624 based on the details provided in the present disclosure.

[0063] The communication interface 630 facilitates communications between the computing device 600 and other devices, which may also be computing devices as described in relation to Figure 6. In various embodiments, the communication interface 630 includes antennas for wireless15508264568.1Attorney Docket No.: 1956788.00447Client Docket No.: 2023-209-PCT communications and various wired communication ports. The computing device 600 may also include or be in communication, via the communication interface 630, one or more input devices (e.g., a keyboard, mouse, pen, touch input device, etc.) and one or more output devices (e.g., a display, speakers, a printer, etc.).

[0064] Although not explicitly shown in Figure 6, it should be recognized that the computing device 600 may be connected to one or more public and / or private networks via appropriate network connections via the communication interface 630. It will also be recognized that software instructions may also be loaded into the non-transitory computer readable medium of the memory 620 from an appropriate storage medium or via wired or wireless means.

[0065] Accordingly, the computing device 600 is an example of a system that includes a processor 610 and a memory 620 that includes instructions that (when executed by the processor 610) perform various embodiments of the present disclosure. Similarly, the memory 620 is an apparatus that includes instructions that when executed by a processor 610 perform various embodiments of the present disclosure.

[0066] In addition to the embodiments described above, many examples of specific combinations are within the scope of the disclosure, some of which are detailed below:

[0067] Clause 1 : A catheter system, comprising: a catheter, comprising: a catheter body having a proximal end, a distal end, and a lumen therebetween; and an electrode, comprising a first contact and a second contact located at the distal end of the catheter; and an impedance measuring device, in electrical communication with the first contact and the second contact.

[0068] Clause 2: The system of any of clauses 1-15, further comprising a pressure source, connected to the proximal end of the catheter and in fluid communication with the distal end via the lumen.

[0069] Clause 3 : The system of any of clauses 1-1 , wherein the pressure source is a negative pressure source or a positive pressure source.

[0070] Clause 4: The system of any of clauses 1-15, wherein a magnitude and a duty cycle of a pressure imparted to by the pressure source is automatically selected by the pressure source based on a measured impedance value from the electrode corresponding to an obstruction-profile associated with the measured impedance value, the magnitude, and the duty cycle.16508264568.1Attorney Docket No.: 1956788.00447Client Docket No.: 2023-209-PCT

[0071] Clause 5: The system of any of clauses 1-15, further comprising a flowmeter disposed in the lumen or the pressure source, configured to measure a flow of liquid through the lumen when pressure is applied to the catheter by the pressure source.

[0072] Clause d: The system of any of clauses 1-15, further comprising: a database in communication with the impedance measuring device and the pressure source, configured to select a given pressure profile from a plurality of pressure profiles by which the pressure source applies pressure to the distal end, wherein the given pressure profile corresponds to a type of obstruction identified via an impedance range measured by the impedance measuring device.

[0073] Clause 7: The system of any of clauses 1-15, wherein the given pressure profile is a learned profile developed according to a machine learning model for removal of the type of obstruction identified via the impedance range to optimally remove the type of obstruction from a biological lumen via aspiration.

[0074] Clause 8: The system of any of clauses 1-15, where in an impedance measuring configuration, the first contact and the second contact touch a target substance within a biological space, and impedance is measured by the impedance measuring device.

[0075] Clause 9: The system of any of clauses 1-15, wherein the impedance measuring device measures the impedance via an alternating current (AC) signal passed from the first electrode to the second electrode through the substance, the AC signal having a frequency of between 1 kilohertz (kHz) and 100 kHz.

[0076] Clause 10: The system of any of clauses 1-15,, wherein the first contact and the second contact are disposed within a shell and each include a measuring surface exposed from the shell.

[0077] Clause 11 : The system of any of clauses 1-15, wherein the first contact and the second contact are exposed from at least one of a distal tip of the catheter and internal lumen of the catheter.

[0078] Clause 12: The system of any of clauses 1-15, wherein the electrode is mounted to the distal end and exposes at least two surfaces of each of the first contact and the second contact.

[0079] Clause 13: The system of any of clauses 1-15, further comprising: a support structure defined within a shell; a first conductor defined within the shell that is electrically isolated from the support structure and is in electrical communication with the first contact; and a second conductor defined within the shell that is electrically isolated from the support structure and the first conductor and is in electrical communication with the second contact.17508264568.1Attorney Docket No.: 1956788.00447Client Docket No.: 2023-209-PCT

[0080] Clause 14: The system of any of clauses 1 -15, further comprising: a support structure defined within a shell, comprising a plurality of supports; wherein a first support of the plurality of supports is electrically isolated from other supports of the plurality of supports and is in electrical communication with the first contact; and wherein a second support of the plurality of supports is electrically isolated from other supports of the plurality of supports and is in electrical communication with the second contact.

[0081] Clause 15: The system of any of clauses 1-15, further comprising: a fluoroscope, comprising a radio source and a viewing device, wherein the electrode defines a radio-opaque maker viewable on the viewing device by blocking or reflecting rays generated by the radio source.

[0082] Clause 16: A catheter, comprising: a shell, defining a lumen having openings at a proximal end and a distal end of the catheter; and an impedance measuring means, comprising a first contact and a second contact located at the distal end of the catheter.

[0083] Clause 17: The catheter of any of clauses 16-20, wherein the impedance measuring means is partially exposed from a tip surface of the shell, such that a first portion of each of the first contact and the second contact is covered by the tip surface and a second portion of each of the first contact and the second contact is exposed from the tip surface.

[0084] Clause 18: The catheter of any of clauses 16-20, wherein the impedance measuring means is mounted to at least a tip surface of the shell and covers a portion of the tip surface.

[0085] Clause 19: The catheter of any of clauses 16-20, further comprising: a support structure defined within the shell; a first conductor defined within the shell that is electrically isolated from the support structure and is in electrical communication with the first contact; and a second conductor defined within the shell that is electrically isolated from the support structure and the first conductor and is in electrical communication with the second contact.

[0086] Clause 20: The catheter of any of clauses 16-20, further comprising: a support structure defined within the shell, comprising a plurality of supports; wherein a first support of the plurality of supports is electrically isolated from other supports of the plurality of supports and is in electrical communication with the first contact; and wherein a second support of the plurality of supports is electrically isolated from other supports of the plurality of supports and is in electrical communication with the second contact.

[0087] Clause 21 : A method, comprising: inserting a distal end of a catheter into a biological lumen; placing a proximal end of the catheter into fluid communication with a negative pressure18508264568.1Attorney Docket No.: 1956788.00447Client Docket No.: 2023-209-PCT source; establishing electrical communication between an electrode located at the distal end of the catheter and an impedance measuring device; measuring an impedance at the distal end; and adjusting, automatically, a pressure imparted by the negative pressure source based on the impedance measured.

[0088] Clause 22: The method of any of clauses 21-26, wherein the pressure imparted by the negative pressure source is adjusted based on the impedance measured via a given obstructiontype characterization profde of a plurality of obstruction-type characterization profdes corresponding to ranges of impedance values for different types of obstructions, including at least two categories of clots, wherein the impedance as measured is within a given range of impedance values that correspond to the given obstruction-type characterization profde.

[0089] Clause 23: The method of any of clauses 21-26, further comprising: measuring a second impedance at the distal end at a time after the impedance was measured; and readjusting, automatically, the pressure imparted by the negative pressure source based on the second impedance measured.

[0090] Clause 24: The method of any of clauses 21-26, wherein adjusting the pressure includes at least one of: adjusting a magnitude of the pressure imparted by the negative pressure source; and adjusting a duty cycle of the pressure imparted by the negative pressure source.

[0091] Clause 25: The method of any of clauses 21-26, further comprising: measuring a flowrate of media through the lumen; and wherein adjusting the pressure imparted by the negative pressure source is further based on the flowrate.

[0092] Clause 26: The method of any of clauses 21-26, further comprising: measuring an internal impedance within the lumen; and wherein adjusting the pressure imparted by the negative pressure source is further based on the internal impedance.

[0093] Clause 27: A method, comprising: measuring an impedance between contacts of an electrode located at a distal end of a catheter inserted into a biological lumen; and imparting, automatically, via a negative pressure source in fluid communication with a proximal end of the lumen, a negative pressure at the distal end based on the measured impedance.

[0094] Clause 28: The method of any of clauses 27-34, wherein a magnitude and a duty cycle of the negative pressure imparted at the distal end are chosen based on the measured impedance corresponding to a given obstruction-profile of a plurality of obstruction-profiles, wherein each obstruction profile of the plurality of obstruction profiles is associated with a range of impedance19508264568.1Attorney Docket No.: 1956788.00447Client Docket No.: 2023-209-PCT values, a given pressure magnitude, and a given duty cycle for negative pressures to aspirate a given type of obstruction from biological lumens.

[0095] Clause 29: The method of any of clauses 27-34, wherein the magnitude and the duty cycle of the negative pressure imparted at the distal end is steady over time with a value of the magnitude chosen by the given obstruction-profile using a machine learning model.

[0096] Clause 30: The method of any of clauses 27-34, wherein the magnitude and the duty cycle of the negative pressure imparted at the distal end vary over time in a pattern chosen by the given obstruction-profile using a machine learning model.

[0097] Clause 31 : The method of any of clauses 27-34, wherein the negative pressure continues to be imparted at the distal end after aspiration of the obstruction according to the given obstruction-profile.

[0098] Clause 32: The method of any of clauses 27-34, further comprising: measuring a subsequent impedance between the contacts of the electrode at a subsequent time to imparting the negative pressure according to the given obstruction-profile; selecting a subsequent obstructionprofile from the plurality of obstruction profiles based on the subsequent impedance; and adjusting, automatically, the magnitude and the duty cycle of the negative pressure according to the subsequent obstruction-profile.

[0099] Clause 33: The method of any of clauses 27-34, further comprising: measuring an internal impedance between within a lumen of the catheter; wherein the magnitude and the duty cycle of the negative pressure imparted at the distal end are chosen further based on the internal impedance.

[0100] Clause 34: The method of any of clauses 27-34, further comprising: measuring a flowrate of material through a lumen of the catheter; wherein the magnitude and the duty cycle of the negative pressure imparted at the distal end are chosen further based on the flowrate.

[0101] Certain terms are used throughout the description and claims to refer to particular features or components. As one skilled in the art will appreciate, different persons may refer to the same feature or component by different names. This document does not intend to distinguish between components or features that differ in name but not function.

[0102] As used herein, the term “optimize” and variations thereof, is used in a sense understood by data scientists to refer to actions taken for continual improvement of a system relative to a goal. An optimized value will be understood to represent “near-best” value for a given20508264568.1Attorney Docket No. : 1956788.00447Client Docket No.: 2023-209-PCT reward framework, which may oscillate around a local maximum or a global maximum for a “best” value or set of values, which may change as the goal changes or as input conditions change. Accordingly, an optimal solution for a first goal at a given time may be suboptimal for a second goal at that time or suboptimal for the first goal at a later time.

[0103] As used herein, various chemical compounds are referred to by associated element abbreviations set by the International Union of Pure and Applied Chemistry (IUPAC), which one of ordinary skill in the relevant art will be familiar with. Similarly, various units of measure may be used herein, which are referred to by associated short forms as set by the International System of Units (SI), which one of ordinary skill in the relevant art will be familiar with.

[0104] As used herein, “about,” “approximately” and “substantially” are understood to refer to numbers in a range of the referenced number, for example the range of -10% to +10% of the referenced number, preferably -5% to +5% of the referenced number, more preferably -1% to +1% of the referenced number, most preferably -0.1% to +0.1% of the referenced number.

[0105] Furthermore, all numerical ranges herein should be understood to include all integers, whole numbers, or fractions, within the range. Moreover, these numerical ranges should be construed as providing support for a claim directed to any number or subset of numbers in that range. For example, a disclosure of from 1 to 10 should be construed as supporting a range of from 1 to 8, from 3 to 7, from 1 to 9, from 3.6 to 4.6, from 3.5 to 9.9, and so forth.

[0106] As used in the present disclosure, a phrase referring to “at least one of’ a list of items refers to any set of those items, including sets with a single member, and every potential combination thereof. For example, when referencing “at least one of A, B, or C” or “at least one of A, B, and C”, the phrase is intended to cover the sets of: A, B, C, A-B, B-C, and A-B-C, where the sets may include one or multiple instances of a given member (e.g., A-A, A-A-A, A-A-B, A- A-B-B-C-C-C, etc.) and any ordering thereof. For avoidance of doubt, the phrase “at least one of A, B, and C” shall not be interpreted to mean “at least one of A, at least one of B, and at least one ofC”.

[0107] As used in the present disclosure, the term “determining” encompasses a variety of actions that may include calculating, computing, processing, deriving, investigating, looking up (e.g., via a table, database, or other data structure), ascertaining, receiving (e.g., receiving information), accessing (e g., accessing data in a memory), retrieving, resolving, selecting, choosing, establishing, and the like.21508264568.1Attorney Docket No. : 1956788.00447Client Docket No.: 2023-209-PCT

[0108] Without further elaboration, it is believed that one skilled in the art can use the preceding description to use the claimed inventions to their fullest extent. The examples and aspects disclosed herein are to be construed as merely illustrative and not a limitation of the scope of the present disclosure in any way. It will be apparent to those having skill in the art that changes may be made to the details of the above-described examples without departing from the underlying principles discussed. In other words, various modifications and improvements of the examples specifically disclosed in the description above are within the scope of the appended claims. For instance, any suitable combination of features of the various examples described is contemplated.

[0109] Within the claims, reference to an element in the singular is not intended to mean “one and only one” unless specifically stated as such, but rather as “one or more” or “at least one”. Unless specifically stated otherwise, the term “some” refers to one or more. No claim element is to be construed under the provision of 35 U.S.C. § 112(f) unless the element is expressly recited using the phrase “means for” or “step for”. All structural and functional equivalents to the elements of the various embodiments described in the present disclosure that are known or come later to be known to those of ordinary skill in the relevant art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed in the present disclosure is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims.22508264568.1

Claims

Attorney Docket No. : 1956788.00447Client Docket No.: 2023-209-PCTCLAIMSThe invention is claimed as follows:

1. A catheter system, comprising: a catheter, comprising: a catheter body having a proximal end, a distal end, and a lumen therebetween; and an electrode, comprising a first contact and a second contact located at the distal end of the catheter; and an impedance measuring device, in electrical communication with the first contact and the second contact.

2. The system of claim 1, further comprising a pressure source, connected to the proximal end of the catheter and in fluid communication with the distal end via the lumen.

3. The system of claim 2, wherein the pressure source is a negative pressure source or a positive pressure source.

4. The system of claim 2, wherein a magnitude and a duty cycle of a pressure imparted to by the pressure source is automatically selected by the pressure source based on a measured impedance value from the electrode corresponding to an obstruction-profile associated with the measured impedance value, the magnitude, and the duty cycle.

5. The system of claim 2, further comprising a flowmeter disposed in the lumen or the pressure source, configured to measure a flow of liquid through the lumen when pressure is applied to the catheter by the pressure source.

6. The system of claim 2, further comprising: a database in communication with the impedance measuring device and the pressure source, configured to select a given pressure profile from a plurality of pressure profiles by which the pressure source applies pressure to the distal end, wherein the given pressure profile23508264568.1Attorney Docket No. : 1956788.00447Client Docket No.: 2023-209-PCT corresponds to a type of obstruction identified via an impedance range measured by the impedance measuring device.

7. The system of claim 6, wherein the given pressure profile is a learned profile developed according to a machine learning model for removal of the type of obstruction identified via the impedance range to optimally remove the type of obstruction from a biological lumen via aspiration.

8. The system of claim 1, where in an impedance measuring configuration, the first contact and the second contact touch a target substance within a biological space, and impedance is measured by the impedance measuring device.

9. The system of claim 8, wherein the impedance measuring device measures the impedance via an alternating current (AC) signal passed from the first electrode to the second electrode through the substance, the AC signal having a frequency of between 1 kilohertz (kHz) and 100 kHz.

10. The system of claim 1, wherein the first contact and the second contact are disposed within a shell and each include a measuring surface exposed from the shell.

11. The system of claim 10, wherein the first contact and the second contact are exposed from at least one of a distal tip of the catheter and internal lumen of the catheter.

12. The system of claim 1, wherein the electrode is mounted to the distal end and exposes at least two surfaces of each of the first contact and the second contact.

13. The system of claim 1, further comprising: a support structure defined within a shell; a first conductor defined within the shell that is electrically isolated from the support structure and is in electrical communication with the first contact; and24508264568.1Attorney Docket No. : 1956788.00447Client Docket No.: 2023-209-PCT a second conductor defined within the shell that is electrically isolated from the support structure and the first conductor and is in electrical communication with the second contact.

14. The system of claim 1, further comprising: a support structure defined within a shell, comprising a plurality of supports; wherein a first support of the plurality of supports is electrically isolated from other supports of the plurality of supports and is in electrical communication with the first contact; and wherein a second support of the plurality of supports is electrically isolated from other supports of the plurality of supports and is in electrical communication with the second contact.

15. The system of claim 1, further comprising: a fluoroscope, comprising a radio source and a viewing device, wherein the electrode defines a radio-opaque maker viewable on the viewing device by blocking or reflecting rays generated by the radio source.

16. A catheter, comprising: a shell, defining a lumen having openings at a proximal end and a distal end of the catheter; and an impedance measuring means, comprising a first contact and a second contact located at the distal end of the catheter.

17. The catheter of claim 16, wherein the impedance measuring means is partially exposed from a tip surface of the shell, such that a first portion of each of the first contact and the second contact is covered by the tip surface and a second portion of each of the first contact and the second contact is exposed from the tip surface.

18. The catheter of claim 16, wherein the impedance measuring means is mounted to at least a tip surface of the shell and covers a portion of the tip surface.

19. The catheter of claim 16, further comprising: a support structure defined within the shell;25508264568.1Attorney Docket No. : 1956788.00447Client Docket No.: 2023-209-PCT a first conductor defined within the shell that is electrically isolated from the support structure and is in electrical communication with the first contact; and a second conductor defined within the shell that is electrically isolated from the support structure and the first conductor and is in electrical communication with the second contact.

20. The catheter of claim 16, further comprising: a support structure defined within the shell, comprising a plurality of supports; wherein a first support of the plurality of supports is electrically isolated from other supports of the plurality of supports and is in electrical communication with the first contact; and wherein a second support of the plurality of supports is electrically isolated from other supports of the plurality of supports and is in electrical communication with the second contact.

21. A method, compri sin : inserting a distal end of a catheter into a biological lumen; placing a proximal end of the catheter into fluid communication with a negative pressure source; establishing electrical communication between an electrode located at the distal end of the catheter and an impedance measuring device; measuring an impedance at the distal end; and adjusting, automatically, a pressure imparted by the negative pressure source based on the impedance measured.

22. The method of claim 21, wherein the pressure imparted by the negative pressure source is adjusted based on the impedance measured via a given obstruction-type characterization profile of a plurality of obstruction-type characterization profiles corresponding to ranges of impedance values for different types of obstructions, including at least two categories of clots, wherein the impedance as measured is within a given range of impedance values that correspond to the given obstruction-type characterization profile.

23. The method of claim 21, further comprising:26508264568.1Attorney Docket No. : 1956788.00447Client Docket No.: 2023-209-PCT measuring a second impedance at the distal end at a time after the impedance was measured; and readjusting, automatically, the pressure imparted by the negative pressure source based on the second impedance measured.

24. The method of claim 21, wherein adjusting the pressure includes at least one of: adjusting a magnitude of the pressure imparted by the negative pressure source; and adjusting a duty cycle of the pressure imparted by the negative pressure source.

25. The method of claim 21, further comprising: measuring a flowrate of media through the lumen; and wherein adjusting the pressure imparted by the negative pressure source is further based on the flowrate.

26. The method of claim 21, further comprising: measuring an internal impedance within the lumen; and wherein adjusting the pressure imparted by the negative pressure source is further based on the internal impedance.

27. A method, comprising: measuring an impedance between contacts of an electrode located at a distal end of a catheter inserted into a biological lumen; and imparting, automatically, via a negative pressure source in fluid communication with a proximal end of the lumen, a negative pressure at the distal end based on the measured impedance.

28. The method of claim 27, wherein a magnitude and a duty cycle of the negative pressure imparted at the distal end are chosen based on the measured impedance corresponding to a given obstruction-profile of a plurality of obstruction-profiles, wherein each obstruction profile of the plurality of obstruction profiles is associated with a range of impedance values, a given pressure27508264568.1Attorney Docket No. : 1956788.00447Client Docket No.: 2023-209-PCT magnitude, and a given duty cycle for negative pressures to aspirate a given type of obstruction from biological lumens.

29. The method of claim 28, wherein the magnitude and the duty cycle of the negative pressure imparted at the distal end is steady over time with a value of the magnitude chosen by the given obstruction-profile using a machine learning model.

30. The method of claim 28, wherein the magnitude and the duty cycle of the negative pressure imparted at the distal end vary over time in a pattern chosen by the given obstructionprofile using a machine learning model.

31. The method of claim 28, wherein the negative pressure continues to be imparted at the distal end after aspiration of the obstruction according to the given obstruction-profile.

32. The method of claim 28, further comprising: measuring a subsequent impedance between the contacts of the electrode at a subsequent time to imparting the negative pressure according to the given obstruction-profile; selecting a subsequent obstruction-profile from the plurality of obstruction profiles based on the subsequent impedance; and adjusting, automatically, the magnitude and the duty cycle of the negative pressure according to the subsequent obstruction-profile.

33. The method of claim 28, further comprising: measuring an internal impedance between within a lumen of the catheter; wherein the magnitude and the duty cycle of the negative pressure imparted at the distal end are chosen further based on the internal impedance.

34. The method of claim 28, further comprising: measuring a flowrate of material through a lumen of the catheter; wherein the magnitude and the duty cycle of the negative pressure imparted at the distal end are chosen further based on the flowrate.28508264568.1

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