Detection of thrombus

Abstract

Methods and apparatuses for monitoring, including optically monitoring an aspiration catheter to identify material in proximity with or within the catheter. In particular, described herein are methods and apparatuses that may be used to identify clot material, and to distinguish clot material from blood and / or vessel wall. Also described herein are methods and apparatuses for using ultrasound to monitor an aspiration catheter.

Description

DETECTION OF THROMBUSCLAIM OF PRIORITY

[0001] This patent application claims priority to U.S. provisional patent application no. 63 / 553,618, titled “DETECTION OF THROMBUS,” and filed on February 14, 2024, and to U.S. provisional patent application no. 63 / 709,985, titled “DETECTION OF THROMBUS,” and filed on October 21, 2024, each of which is herein incorporated by reference in its entirety.BACKGROUND

[0002] Blockage of blood vessels may result in serious medical and health issues. For example, a thromboembolism is characteristic of numerous common, life-threatening conditions. Examples of potentially fatal diseases resulting from thrombotic occlusion include pulmonary embolism, deep vein thrombosis, and acute limb ischemia. Acute pulmonary embolism is a significant cause of death in the United States. Pulmonary embolism can be a complication from deep vein thrombosis, which has an annual incidence of 1% in patients 60 years and older. All of the aforementioned diseases are examples of conditions in which treatment may include aspiration or evacuation of clot using a vacuum- assisted thrombectomy procedure.

[0003] However, vacuum-assisted thrombectomy procedures must sometimes be terminated due to the risk of excessive blood loss by the patient, especially when using large aspiration catheters. During aspiration thrombectomy, prior to contacting the clot material and / or when the catheter tip falls out of contact with the clot material (e.g., thrombus or other occlusive material), the tip is exposed to healthy blood and may remove blood at full flow and the blood loss rate may be excessive. In addition, the tip may contact and adhere to the vessel wall, referred to as latching, which may be difficult to distinguish from clot. These problems may be exacerbated where clot is hard and difficult to remove.

[0004] It may also be difficult to determine when clot has been taken into the lumen of the aspiration apparatus, including when the aspiration apparatus is clogged. It would also be very helpful to accurately and / or quantitatively determine how much clot has been removed.

[0005] It would therefore be desirable to provide methods and apparatuses (e.g., systems, devices, etc.) for detecting thrombus using a catheter. It would be particularly useful to provide apparatus and methods for automatically sensing clot (thrombus) to assist in removal of clot material as well as apparatus and methods for detecting wall latch upon aspiration. In addition, it would also be helpful to distinguish types of clot, as well as distinguishing clotfrom blood and clot from vessel wall. The methods and apparatuses described herein may address these issues.SUMMARY OF THE DISCLOSURE

[0006] Described herein are methods and apparatuses identifying the type of material in proximity with the distal end of a catheter. The catheter may be an aspiration catheter. The methods and apparatuses may be configured to monitor one or more of: optical information (e.g., reflectance) and / or ultrasound. In some examples the methods and apparatuses may also use an impedance data stream to assist in identifying clot material, and / or distinguishing clot material from blood and / or wall. Also described herein are methods of probing the local area around the catheter (e.g., the tip of an aspiration catheter) to help characterize the conditions and surrounding materials.

[0007] Described herein are optical sensing methods and apparatuses configured to perform them, for detection of clot material, and / or control of removal of clot material. For example, a method may include: receiving an optical data stream from one or more optical sensors on a distal end region of a catheter; determining, in an ongoing basis based on the optical data stream, if the distal end region is in proximity with blood, non-blood tissue or clot, based on a differential optical signal taken at different wavelengths; and outputting a state classification indicating if the distal end region of the catheter is in proximity with one or more of: blood, non-blood tissue or clot.

[0008] As used herein, “proximity” may refer to material within immediate proximity, up to and including contact. Proximity may include material that is within about 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc. In some examples proximity may refer to proximity to the aspiration opening of the catheter, such as within an extraction region including and adjacent to the aspiration opening from which clot material may be removed by the application of suction (e.g., aspiration).

[0009] In any of these apparatuses, the one or more optical sensors may include an optical emitter and at least one optical detector. The optical emitter and sensor may be paired; in some cases, more than one optical sensor may be used with one optical emitter and / or more than one optical emitter may be used with one or more optical sensors. The optical sensor emitter and sensor may be configured to operate on the same or overlapping wavelengths. Any appropriate optical wavelength may be used, including visible light wavelengths (e.g., one or more wavelengths or regions of wavelengths between 380 to 700 nm), near-infrared light, etc. More than one wavelength or wavelength regions may be used. Any of the optical sensors and emitters described herein may be used with one or moreoptical elements, such as filters, polarizers, lenses, etc. For example, an optical sensor may include a filter to remove light from outside of the detection range.

[0010] Any of these methods may include adjusting the size of a window of time for collecting the differential optical signal of the optical data stream. The window of time may be dynamically adjusted; e.g., any of these methods may include adjusting the size of the window of time, based on one or more of the application of aspiration through the catheter, and / or the optical data stream. In some examples these methods may include adjusting suction through a lumen of the catheter based on the state classification output. The state classification may include indicating if the distal end region of the catheter is in proximity with a vessel wall tissue.

[0011] In general, these methods may be performed within the vasculature. For example, the non-blood tissue may comprise a vessel wall.

[0012] In some examples the methods described herein may be methods of quantifying clot, the method comprising: optically sensing clot material within a suction lumen of a catheter; determining a volume of clot material within the suction lumen based on a velocity of the clot material, a duration of time during which the clot material was sensed, and a cross- sectional area of the suction lumen; and outputting the volume of clot material.

[0013] Any of these methods may include adjusting an applied negative pressure through the suction lumen based on the volume of clot material. Optically sensing the clot material within the suction lumen of the catheter may comprise sensing based on a differential optical signal taken at different wavelengths of light. In some examples determining the volume of clot material comprises sensing a leading edge of the clot material from a first optical sensor at a first location within the suction lumen and sensing the leading edge of the clot material from a second optical sensor at a second location within the suction lumen. Optically sensing clot material may comprise sensing clot material while applying suction through the suction lumen.

[0014] Also described herein are systems, including systems for performing any of these methods. For example, a system may include: an elongate flexible catheter comprising one or more optical sensors configured to detect an optical signal within a lumen of the elongate flexible catheter; one or more processors; and a memory storing computer-program instructions, that, when executed by the one or more processors, perform a computer- implemented method comprising: receiving an optical data stream from one or more optical sensors on a distal end region of a catheter; determining, in an ongoing basis based on the optical data stream, if the distal end region is in proximity with blood, non-blood tissue or clot, based on a differential optical signal taken at different wavelengths; and outputting astate classification indicating if the distal end region of the catheter is in proximity with one or more of blood, non-blood tissue or clot.

[0015] The one or more optical sensors may include an optical emitter and at least one optical detector. In some examples the computer-implemented method may include adjusting the size of a window of time for collecting the differential optical signal of the optical data stream. As mentioned above, the computer-implemented method may further comprise dynamically adjusting the size of the window of time, based on one or more of the application of aspiration through the catheter, and / or the optical data stream. The computer- implemented method may further comprise adjusting suction through a lumen of the catheter based on the state classification output.

[0016] The state classification may include indicating if the distal end region of the catheter is in proximity with a vessel wall tissue. The non-blood tissue may comprise vessel wall.

[0017] For example, a system may include: an elongate flexible catheter comprising one or more optical sensors configured to detect an optical signal within a lumen of the elongate flexible catheter; one or more processors; and a memory storing computer-program instructions, that, when executed by the one or more processors, perform a computer- implemented method comprising: optically sensing clot material within a suction lumen of a catheter; determining a volume of clot material within the suction lumen based on a velocity of the clot material, a duration of time during which the clot material was sensed, and a cross- sectional area of the suction lumen; and outputting the volume of clot material.

[0018] The computer-implemented method may further comprise adjusting an applied negative pressure through the suction lumen based on the volume of clot material. In any of these systems and methods, optically sensing the clot material within the suction lumen of the catheter may comprise sensing based on a differential optical signal taken at different wavelengths of light. Determining the volume of clot material may comprise sensing a leading edge of the clot material from a first optical sensor at a first location within the suction lumen and sensing the leading edge of the clot material from a second optical sensor at a second location within the suction lumen. In some cases, optically sensing clot material comprises sensing clot material while applying suction through the suction lumen.

[0019] This patent application may be related to, may improve on, and / or incorporate, one or more of features or elements of International application no. PCT / US2022 / 035392, filed June 28, 2022, U.S. patent application no. 17 / 866,462, filed on July 15, 2022, which issued as U.S. patent no. 11,730,925, and U.S. patent application no. 18 / 329,532, filed on June 5, 2023, each of which is herein incorporated by reference in its entirety.

[0020] All of the methods and apparatuses described herein, in any combination, are herein contemplated and can be used to achieve the benefits as described herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0021] A better understanding of the features and advantages of the methods and apparatuses described herein will be obtained by reference to the following detailed description that sets forth illustrative embodiments, and the accompanying drawings of which:

[0022] FIG. 1 schematically illustrates one example of an apparatus for sensing clot material.

[0023] FIGS. 2A-2B schematically illustrate an example of optical detection of clot material. FIG. 2 A shows a first example of clot detection using an optical sensor including a photodetector and a light source. FIG. 2B shows a second example of clot detection using a pair of optical sensors.

[0024] FIG. 3 schematically illustrates a method of tracking movement of clot material within a catheter.

[0025] FIG. 4 is a graph showing an example of detection of a clot volume.

[0026] FIGS. 5A-5D illustrate examples of optical sensors including different combinations of light sources and photodetectors. FIG. 5 A shows an example of a narrowband light source and a matching narrow-band detector. FIG. 5B shows an example of a narrow-band light source and a broad-band detector. FIG. 5C shows an example of a broadband light source and a narrow-band detector. FIG. 5D shows an example of a broad-band light source and a matching broad-band detector.

[0027] FIG. 6 illustrates an example of an optical sensor having a plurality of detection bands (e.g., a hyperspectral detector), shown as 1- 5.

[0028] FIGS. 7A-7D show schematic examples of cross-sections through a tube (e.g., catheter, cartridge, etc.) including one or more sensors arranged around the lumen of the tube. FIG. 7A shows an example of a sensor including a light source and a photodetector arranged adjacent to each other on one side of the lumen. FIG. 7B shows an example of a sensor including a light source and a photodetector arranged on opposite side of the lumen. FIG. 7C shows an example of a sensor having a plurality of light sources and sensors arranged radially around the lumen. FIG. 7D shows an example of a pair of light sources and detectors that are arranged on opposite sides of the lumen (e.g., in a scan-type arrangement).

[0029] FIG. 8 illustrates an example of an apparatus including an elongate catheter body having tapered distal tip region with a pair of optical clot sensors on the distal end region and on a more proximal region.

[0030] FIGS. 9 A and 9B illustrate normalized reflected optical spectra for an optical sensor. FIG. 9A shows individual spectra corresponding to different materials (e.g., blood, clot, vessel wall, etc.). FIG. 9B show as an example of a graph of the sum of the absorption spectrum for Clot-Blood, Clot-Wall, and Wall-Blood.

[0031] FIGS. 10A-10F illustrate examples of aspiration catheters, generically shown in FIG. 10F, that may include one or more optical sensors, shown in FIGS. 10B-10F.

[0032] FIG. 11 shows an example of an aspiration catheter apparatus similar to FIG. 10B, in which the optical sensing region extends slightly further than the extraction zone of the aspiration orifice.

[0033] FIG. 12 illustrates an example of a system including an aspiration catheter apparatus similar to that described herein, e.g., for closed-loop blood return, further including a blood return portion that may also be configured to sense (e.g., detect) clot material.DETAILED DESCRIPTION

[0034] Described herein are methods and apparatuses for identifying characteristics of material, including type and / or amount, that is adjacent to or within a catheter using one or more optical and / or ultrasound sensors. These methods and apparatuses may be used in combination with other sensing modalities (including electrical sensing, such as but not limited to impedance sensing) and may be integrated with a catheter, an aspiration catheter, for removing clot material. In particular, described herein are methods and apparatuses for optically characterizing clot material that may be performed as part of a clot removal procedure. Also described herein are apparatuses configured to optically characterize a material within, in contact with, and / or adjacent to, a catheter (e.g., aspiration catheter). These apparatuses (systems, devices, etc.) may be configured to report the one or more characteristics of the material to the user and / or to use the identified one or more characteristic in operation of the apparatus.

[0035] For example, described herein are methods and apparatuses for optical monitoring. The methods and apparatuses described herein may use optical sensing or in some cases a combination of optical sensing and sensing in a second modality, such as ultrasound, electrical sensing, e.g., as a combination of both optical and electrical sensing and / or optical and ultrasound sensing. Thus, any of the methods and / or apparatus for opticalsensing described herein may be used with an electrical (e.g., impedance) monitoring / sensing. Alternatively, a method or apparatus may just use optical sensing.

[0036] Also described herein are methods and apparatuses for ultrasound monitoring. The methods and apparatuses described herein may use ultrasound sensing or in some cases a combination of ultrasound sensing and sensing in a second modality, such as optical and / or electrical sensing, e.g., as a combination of both optical and electrical sensing. Thus, any of the methods and / or apparatus for ultrasound sensing described herein may be used with an electrical (e.g., impedance) monitoring / sensing. Alternatively, a method or apparatus may just use ultrasound sensing. In general, any of the apparatuses and methods described herein for use with optical sensing may be adapted for use with ultrasound sensing in place of the optical sensing.

[0037] Described herein are methods and apparatuses (e.g., devices, systems, etc., including software, hardware and / or firmware) for interpreting and analyzing sensed data, including sensed optical and / or ultrasound data, and in particular optical data collected by one or more optical sensors (emitters and / or receivers) placed on or near the aspiration orifice, within the lumen of the catheter, etc. In some cases, the data may be collected from optical sensors placed on or near the rim of an aspiration orifice of a thrombectomy catheter. In some cases, the data may be collected from optical sensors placed on or within the aspiration lumen of a thrombectomy catheter. These methods and apparatuses may process sensed optical data to characterize (e.g., classify and / or quantify the sensed material) external to and / or internal to the catheter during a thrombectomy procedure. The sensed optical data may be collected periodically or continuously or some combination of the two. For example, the sensed data may be collected with frequency of between about 0.2 Hz to 1 MHz). In some cases, the sensed data may be collected continuously. In some cases, the sensor(s) may be turned on for one or more durations that may be periodic or on-demand. The sensed data may be examined over a window of time (e.g., to determine changes within the widow of time corresponding to one or more conditions and / or materials. In some cases, the sensed optical data (and / or additional sensing modality data) may be analyzed as a stream of data (e.g., data stream).

[0038] The methods and apparatuses for analyzing the data streams described herein may identify / classify material within the catheter and / or at or near a distal end region (tip) of the catheter, including characterizing the material within a classifications / identification state, such as: air, saline, blood, non-blood tissue (e.g., tumor, vessel wall, etc.), clot (and in particular type of blood clot). The non-blood tissue, referred to herein as simply “tissue” may be characterized as vessel wall and / or type of tissue (e.g., common tissues including inferiorvena cava (IVC), main pulmonary artery (MPA), right pulmonary artery (RPA), and left pulmonary artery (LPA), etc.).

[0039] FIG. 1 illustrates one example of an apparatus as described herein, which may be configured for receiving optical signals from one or more optical sensors (e.g., optical transducer 168), and / or electrical signals from electrodes. The optical sensors may be positioned on or near the rim of an opening (e.g., aspiration opening) or on an opposite side of the device. In some cases, the optical sensor(s) may be within the suction lumen (not visible in FIG. 1), e.g., at a proximal end region (near the aspiration opening, on the aspiration opening, opposite the aspiration opening, etc.) within a middle region of the suction lumen, at a proximal end region of the suction lumen, etc. In some examples the apparatuses and methods described herein may be used on or part of a device (including, but not limited to, a catheter). The device may be insertable or implantable into the body. Properties of the clot material may be determined and output to a user, stored, transmitted and / or further processed.

[0040] In FIG. 1, the apparatus includes a flexible catheter having an elongate catheter body, a proximal end region and a distal end region. The distal end region 177 is configured to be inserted into the body, including over a guidewire and / or guide catheter 137. FIG. 1 includes a flexible elongate body 113 (shown in two parts in FIG. 1) that includes a distal end region 177 with a guide channel 131 for a guide or diagnostic catheter 137 (and / or guidewire) extending from a distal end opening through the length of the elongate body. The distal end region may include an extraction chamber region having an aspiration opening 121 into a suction lumen that extends along the length of the flexible elongate body. The aspiration opening 121 at the distal end region of the flexible elongate body in this example is sidefacing (e.g., on a tapered distal end region). The distal end region may also include one or more openings into the suction lumen on a side of the distal end region that is opposite from the aspiration opening (not visible in FIG. 1).

[0041] The optical sensors may include a light emitter (e.g., light source) that is part of or paired with an optical detector (e.g., photodetector). The optical sensor may be connected to a proximal connector (optical connector), via an electrical line and / or in some cases one or more fiber optic line. In some cases, the sensor (optical sensor) may transduce an optical signal into electrical signal for transmitting down the apparatus to the controller 115.

[0042] In some cases, these apparatuses may include one or more electrical sensors. For example, in FIG. 1, the distal end region of the apparatus also includes two electrodes 158, 158’ positioned at a rim of the aspiration opening. In this example the electrodes are positioned at the 2 o’clock and 10 o’clock position, generally towards the proximal end of theaspiration opening. The electrodes may be positioned anywhere on the rim, including at the distal-most (6 o’clock) and proximal-most (12 o’clock) position, at the 3 o’clock, and the 9 o’clock position, etc. The electrodes may be any appropriate size, such as between about 0.1 and 3 cm (e.g., between about 0.5 and 2 cm, etc.) long (around the perimeter of the aspiration opening). Although two electrodes are shown, in some cases only one electrode is present, and in some cases more than two electrodes may be present (e.g., three, four, five, etc.). The electrodes may be configured to operate as a pair (e.g., in a bipolar configuration). In some cases, the electrodes may be configured to operate as monopolar electrodes. In some examples, the electrodes may be multiplexed together. It may be helpful to sense material in contact with the aspiration opening. In some examples the electrode(s) may be positioned in the proximal half (e.g., the proximal 40%, proximal 35%, proximal 30%, etc., such as between the 9 o’clock and 3 o’clock, or more preferably between 10 o’clock and 2 o’clock, or between 11 o’clock and 1 o’clock positions). Additional electrodes may be positioned on the distal end region, and / or on the guidewire / guide catheter 137; in some examples, electrodes may be positioned proximal to the aspiration opening 121, on the outside and / or the inside of the catheter. For example, one or more internal electrodes may be positioned just proximally to the aspiration opening and the aspiration opening electrodes 158, 158’. The internal impedance sensing electrodes may be configured to detect material (e.g., clot material) within the suction lumen and may be used in conjunction (or coordinated) with the aspiration opening sensor electrodes to confirm that the aspiration opening is in contact with clot material, or to distinguish from vessel wall when force (e.g., suction) is applied to drive the distal end region, including the aspiration opening, into a material. The internal impedance sensing electrodes may be spaced from the aspiration opening (proximal end) by between about 0.1 and 30 mm (e.g., between about 1 and 20 mm, between about 1 and 10 mm, etc.). The internal impedance sensing electrodes in this example includes two annular electrodes, extending partially around the wall of the suction lumen, but any shape electrode may be used. The internal impedance sensing electrodes may be separated from each other by any appropriate distance, e.g., between about 0.1 and 10 mm (e.g., between about 0.5 and 5 mm, 0.5 and 3 mm, etc.). The electrodes may be referred to as sensing electrodes and / or in some variations, as impedance sensing electrodes, and may each be electrically coupled to an electrical line, wire, trace, etc., extending proximally down the length of the flexible elongate body and into the proximal handle 109. The suction lumen may extend from the elongate body into the handle and may include a suction port 197 at the proximal end.

[0043] In FIG. 1 the apparatus also includes the controller 115 that couples or connects (via a connector 187 to each of the sensors (e.g., optical sensor(s), and in some cases theelectrodes forming the electrical sensors). The controller in this example may include one or more outputs (e.g., display / LED, lights, tone / sound, etc.). The controller may indicate (visually, audibly, etc.) the nature of the material that the sensor(s) is / are at or adjacent to a distal end of the device, within the lumen of the device and / or at the aspiration opening. For example, the controller may process optical (and in some cases, electrical) signals using a sensing sub-system 117, including applying energy, e.g., light, to the sensor emitter (e.g., light source) and sensing an optical signal, such as absorption, to generate a data stream, which may be an ongoing data stream, and determining from the data stream the one or more classification states based on the ongoing data stream as described herein. For example, the sensing sub-system may include control logic, memory and / or one or more processors (or may access the one or more processor of the controller 115) to determine if the sensors (and in some cases in which the sensors are configured to sense from the distal end of the device, the distal end region of the catheter and / or the aspiration opening region) are near or in contact with air, saline, blood, non-blood tissue (e.g., vessel wall, vegetation), clot material, vessel wall, etc.

[0044] The sensing sub-system may be part of or separate from the controller and / or a removal (e.g., suction-controlling) sub-system 119. In any of these examples the sensing subsystem, controller and / or removal sub-system may include one or more processors or may share one or more processors. In general, a processor includes hardware that runs software (e.g., computer program code). Specifically, the term ‘processor’ may include or be part of a controller and may encompass not only computers having different architectures such as single / multi-processor architectures and sequential (Von Neumann) / parallel architectures but also specialized circuits such as field-programmable gate arrays (FPGA), application specific circuits (ASIC), signal processing devices and other devices. The sensing subsystem may characterize the material sensed (e.g., type of material) and / or one or more properties of the material, such as volume, flow rate, etc.

[0045] The controller (and / or the sensing sub-system) may output and indicate any of the information described above, in some examples as an ongoing data stream. The sensed information may be ‘raw’ or modulated (e.g., filtered, smoothed, etc.). The output of sensing sub-system may be analyzed, stored, transmitted, etc. The controller may also control the operation of clot removal, including the application of aspiration through the aspiration lumen and distal aspiration opening, e.g., using the removal sub-system 119, which may include one or more aspiration sensors (e.g., sensing the application of aspiration) and / or pumps, switches, etc.

[0046] The methods and apparatuses described herein may generate a data stream using some or all of the sensors (e.g. optical sensors) of the device in order to analyze the data stream to determine a state at the catheter tip and / or suction lumen. The data stream may be generated and monitored, sensed, recorded, etc. in real time or near real-time. The data stream may be a continuous (ongoing for a fixed or variable amount of time) or discrete data stream, or in some examples an intermittent data stream.

[0047] The methods and apparatuses described herein may accurately sense when the aspiration catheter tip (including the sensor(s)) is in proximity to clot material and this information may be used to automatically control the aspiration of that clot out of the body. These methods and apparatuses may signal when the aspiration orifice is in contact with clot, for instance, to drive an electro-mechanical interface to perform aspiration. That interface (e.g., a removal sub-system as described in FIG. 1) may include a valve to a vacuum chamber, or a motor drive to pull suction (e.g., a pump). The methods and apparatuses may signal to turn off the aspiration when the catheter tip is no longer in contact with clot. This mechanism of operation may allow for the most efficient use of aspiration to only extract blood clots and may minimize blood loss. This automatic aspiration control may be enabled / disabled by the user of the device.

[0048] In general, the methods and apparatuses described herein may include sensors (e.g., optical and / or ultrasound) in any appropriate region. In some examples, the sensors may be at or on the aspiration opening. Alternatively or additionally, the sensors may be distal to the aspiration opening.

[0049] The methods and apparatuses described herein may also be configured to determine what type of blood clot is on or near the sensor(s) based on the sensed values, including based on the optical data stream. The optical properties of clot material may depend on the composition and structure of the clot, and may be based on the age, composition of fibrin, platelets, and red blood cells in the clot. These variations can result in differences in their optical properties, including absorbance.

[0050] In any of the methods and apparatuses described herein, optical spectroscopy techniques may be used, including measuring absorbance and / or reflectance across a range of optical wavelengths / frequencies. Different clot types may exhibit unique optical spectra due to variations in their cellular and structural compositions. Optical spectroscopy can provide detailed information about the clot's properties at different wavelengths. The apparatuses described herein may detect and differentiate clot types based on the optical patterns; by analyzing the optical data stream obtained from these sensors, it's possible to categorize clots into types such as fibrin-rich, platelet-rich, or red blood cell-rich clots. The ability to identifydifferent clot types through optical analysis may improve clinical diagnostics and treatment. The methods described herein may provide a standardized technique for measurements and / or for interpretations of otherwise complex data.

[0051] Optical and / or ultrasound sensing may provide information about the quantity, quantity and / or location of material, including clot material, as it is being removed. In any of the methods and apparatuses described herein, this analysis, using one or more optical sensors, may be performed as part of a blood filtration system (or sub-system) and / or in conjunction with or instead of manual observation, measuring, and weighing. Similarly, one or more ultrasound transducers may be used in conjunction with any of these methods and apparatuses. In some cases, the ultrasound transducer may be used as part of a blood filtration system (or sub-system) and / or in conjunction with or instead of manual observation, measuring, and weighing.

[0052] For example, described herein are optical sensing apparatuses and method for analyzing material removed from the patient, including but not limited to obstructive material (e.g., clot material), as it travels through the removal catheter or other portion of the system, including blood suction and / or filtration portions. These optical methods may help improve analysis accuracy and speed during removal of the clot material. In some cases, these methods and apparatuses may confirm the readings from the electrical (e.g., impedance) sensing and control described above. In some examples the methods and apparatuses described herein may include apparatuses and methods that detect clot material, and / or determine the type or composition of the clot material, and / or distinguish clot material from wall material, and / or confirm the presence and location of clot material in a position relative to the aspiration opening and / or may automatically or semi -automatically activate aspiration through the lumen of the catheter, using any of the techniques described above. In some cases, the methods and apparatuses may further include any of the optical sensors and components, including applying any of these techniques, following the aspiration of material to confirm the identity, size, weight, etc. of the of the clot material.

[0053] Thus, any of these methods and apparatuses may include two or more optical sensors, that may be installed in-line with the catheter lumen. An optical sensor may include at least one light source, and at least one photodetector. The optical source may be any appropriate optical source, including a light emitting diode (LED), laser, etc. Any appropriate wavelength(s) of light may be used, including visible light and / or infrared, or near-infrared light. The one or more photodetectors may include a photodetector comprising any appropriate photodetector, including for one or more wavelengths or wavelength ranges. These optical sensors may include one or more additional optical components, includingfilters, lenses, waveguides, etc. The apparatuses and methods described herein may include a lumen for coupling in-line with the suction lumen and / or catheter lumen of the aspiration catheter and / or may be integrated into the aspiration catheter.

[0054] In some examples the methods and apparatuses described herein may include an optical sensor including a source-detector arrangement that is configured to operate in a wavelength, or ranges of wavelengths, in which blood and blood-clot (e.g., obstructive material) have substantially different absorption profiles.

[0055] In any of these methods and apparatuses one or more optical sensors may be used. In some cases, the use of two optical sensors, e.g., in locations a known distance apart, may enable the apparatus or method to estimate the speed that the clot travels in the lumen. The signal from each optical sensor may allow estimation of the length of the clot, which, together with knowledge of lumen cross-section, can be used by the apparatus or method to calculate the volume of the clot and using estimated specific weight for clot allow calculating approximate clot weight. Thus, any of these methods and apparatuses may be configured to determine a weight and / or volume of the clot material.

[0056] FIGS. 2A-2B illustrate one example of an apparatus including an optical sensor as described herein. In FIG. 2A, the apparatus 2000 includes a lumen 2043. An optical sensor including a photodetector 2045 (e.g., optical detector) and a light source 2047 (e.g., an optical emitter, such as an LED light source) are shown oriented to transmit light into and receive reflected light out of the lumen. In FIG. 2A the photodetector 2045 is positioned adjacent to the light source 2047 on an outer region, external to the lumen 2043. In any of these apparatuses the photodetector and / or light source may be coupled outside of the lumen, but may receive / transmit light through the wall (or a region of the wall) forming the lumen. In some examples the photodetector and / or light source may be positioned within the lumen. In FIG. 2A a clot material 2041 is shown in the lumen 2043 and reflecting light transmitted from the light source 2047. Some of the light may be absorbed, and some (e.g., particular wavelengths) may be reflected. The amount or ratio of absorbed vs. reflected light may be sensed and used to determine or confirm the presence, composition and / or the amount of the material (e.g., clot material) within the lumen.

[0057] FIG. 2B illustrates another example of an apparatus including a pair of optical sensors as described herein. In this example, the apparatus 2000’ includes a lumen 2043, that is at clear or transparent to the emitted / sensed light over at least a region of the length of the wall(s) forming the lumen, similar to the apparatus shown in FIG. 2A. In FIG. 2B, a first sensor includes a photodetector 2045 and a light source 2047 that are adjacent to each other and are positioned distally relative to the lumen compared with a second sensor including asecond photodetector 2045’ and a second light source 2047’. In any of these apparatuses and methods the first and second sensors may be positioned on or behind a wall of the lumen and / or on the wall of the lumen. In FIG. 2B the first and second sensors are shown on a printed circuit board (PCB) 2049 that may be positioned adjacent to the lumen, as shown.

[0058] FIG. 3 schematically illustrates another example of an apparatus including a pair of optical sensor 2140, 2140’. Each sensor may include a light emitter (e.g., LEDi, LED2) and a photodetector (e.g., PDi, PD2). The first and second sensors may be a predetermined distance apart, and in particular, the photodetectors may be a predetermined distance apart, e.g., LPD. In this example a clot 2141, 2141’ is shown moving through the lumen of the apparatus. The lumen is shown having a fixed cross-sectional area between the first and second sensors, shown having a circular cross-sectional area having a radius, r. As the clot 2141 moves down the length of the lumen it passes the first sensor 2140, then the second sensor 2140’. Each sensor may detect, via the photodetectors, a signal corresponding to the passage of the clot material that is distinct from blood and other materials. This is illustrated in the graphs shown in FIG. 4. The top graph shown the signal from the first sensor (first photodetector, PDi) and the bottom graph shows the signal from the second sensor, PD2. In FIG. 4, the upper signal profile represents the time that that the clot is passing the first sensor, tciot, which is a function of the rate of movement of the clot as well as the size of the clot (e.g., length of the clot, Lciot). In some examples, this may be determined by identifying the leading edge of the clot material signal as it passes a first senor compared to when the leading edge passes a second sensor. For example, the lower signal in this example reflects the passage of the same clot material past the second sensor. The system and / or apparatus may match the signals based on the times that the clot is passing each sensor, tciot, and / or based on an estimated flow rate. Alternatively, in some examples, the apparatus and / or method may use the optical signals from the first and second optical detectors to estimate a clot size (length) based on the travel time between the first and second sensors, tpo, and based on the time the clot takes to pass the first and / or second sensors, tciot.

[0059] For example, the velocity of the clot material in the apparatus may be estimated as the length of the distance between the first and second photodetectors (LPD) and the time to travel this distance, tpo. The length of the clot may be determined as this velocity (LPD / tpo) times the time it takes for the clot to pass the first or second photodetector (tciot), e.g., Lciot = (LPD / tpo) * Liot. Finally, a volume of the colt material may be approximated or estimated using the cross-sectional area of the region between the first and second sensors, A. In the example shown in FIG. 3, this may be approximated as Lciot * A, or Lciot * 7ir2.

[0060] In any of these optical sensing methods and apparatuses, the optical sensor may include either one or more narrow-band sources and / or one or more wide-band sources, and the optical detector may include one or more narrow-band detectors and / or one or more wideband detectors (e.g., photodetectors). For example, FIGS. 5A-5D illustrated matching pairs of optical detectors (e.g., photodetectors) and optical sources (e.g., LEDs). FIG. 5A shows the wavelength profile for a sensor including a narrow-band optical detector and a matching narrow-band detector. FIG. 5B shows a wavelength profile for a sensor including a narrowband source and a broad-band detector. FIG. 5C shows a wavelength profile for a sensor including a broad-band source and matching narrow-band detector. FIG. 5D shows a wavelength profile for a sensor including a d) broad-band source and broad-band detector.

[0061] In general, any of these optical sensors may produce several measurements for overlapping or non-overlapping wavelength bands (e.g., may be configured as hyperspectral detectors). As mentioned, these methods and apparatuses may include a wavelength band in a visible light range having a frequency of between about 400 nm-700 nm or any sub-region(s) therefore, and / or a wavelength in a near-infrared (NIR) wavelength band of between about 700 nm-2500 nm, or any sub-region(s) therefore. The wavelength (X) may be determined by the difference in characteristics absorption between blood and clot, which may improve specificity and accuracy. In some examples this may be achieved with a broad-band source and multiple narrowband detectors, as shown in FIG. 6.

[0062] In any of these methods and apparatuses, an optical sensor may include one or more than one source and / or more than one detector, that may be arranged to improve spatial resolution. FIGS. 7A-7D illustrate different alternative configurations that may be used. For example, FIG. 7A illustrates an example of a sensor including a light source 2547 and a detector 2545 (photodetector) that are on the same side of the lumen, adjacent to each other. Thus, the light sensed may be reflected by the material (e.g., clot material). FIGS. 7B shows an example of an apparatus including a sensor having a light source 2547 and an optical detector 2545 that are on opposite sides of the lumen, across from each other, and may detect light that passes through the clot material (e.g., excluding the reflected and absorbed light). Similarly, FIG. 7C also detects transmitted light through the clot material from a plurality of radially arranged optical emitters 2547, 2547’, 2547” (e.g., LEDs) and optical detectors (e.g., photodetectors) 2545, 2545’, 2545”. Any appropriate number of optical sources and optical detectors may be used. This configuration may help detect the passage of clot fragments that might not fill the entire cross-section of the tube or lumen. FIG. 7D illustrates an example of a scan-type arrangement of sources 2547, 2547’ and detectors 2555, 2555’. One or more lightsources 2547, 2547’ may transmit light and an array of detectors 2555, 2555’ may receive light.

[0063] Any of these apparatuses may include one or more additional optical sensors in various locations along the aspiration path. In some examples, the optical sensors may be positioned within the aspiration catheter. For example, one or more optical sensors may be positioned within a catheter aspiration path or other tubing locations, in-line with the aspiration flow path, and may provide confirmation that all or some of the clot that entered the catheter has left the catheter, or if clot material is present in a location along the aspiration path, typically between sensors. For example, FIG. 8 shows an examples of an aspiration catheter 2663 that includes a distal tip region 2664 with an aspiration opening; a first optical sensor 2656 is positioned within the distal end region of the aspiration lumen and a second optical sensor 2656’ is on a more proximal end 2665 of the catheter. In the example shown in FIG. 8, a clot material 2641 may enter the distal end through the aspiration opening (after confirmation using the impedance sensing methods and apparatuses described above) and information about the clot material may be determined from the first and second optical sensors 2656, 2656’ as described above. In some examples, the apparatus may track the clot material within the catheter and determine the rate, and / or size (e.g., volume) of clot material removed.

[0064] In some examples one or more optical sensors may be used to differentiate blood, wall and / or clot material (including a mix of blood with clot). In some cases, two wavelengths of light may be used to separate these different types of tissue. For example, clot material may be detected using a differentiation measure, e.g., the sum of the absolute value in amplitude difference between the three materials. Normalizing for the total received power (area under the curve), may allow the apparatus to distinguish clot through blood, as the contribution from the blood goes away, allowing detection of just clot material. For example, FIG. 9A shows an example of an optical sensor that may be used to image material at the distal end region of a catheter. The optical sensor may detect the optical reflectance of the material. In FIG. 9 A, data was collected using an optical sensor coupled to a measuring system, so that a spectrum of individual wavelengths could be applied. In some examples the two wavelengths may be within the range of between about 630nm and 850nm. For example, the two wavelengths used may be centered on approximately 665nm for the first, and a second centered on approximately 805nm. One or more optical filters may be used. For example, an optical notch filter may be used.

[0065] FIG. 9A shows an example of a normalized reflected optical spectra for an optical sensor, showing traces corresponding to blood 2701, human clot material 2703, human vesselmaterial 2705, blood and clot material 2711, and blood and vessel material 2709, over an optical spectrum extending between 360 and 1050 nm.

[0066] FIG. 9B shows that, when this data is normalized, e.g., by the area under the curve 2733, the effect of the blood (e.g., the sum of the clot signal and blood signal approximately equals the clot signal, and wall and blood approximately equals the wall signal) may be eliminated, leaving just the difference between blood and wall as compared to clot material.

[0067] The example graph shown in FIG. 9B is computed from the sum of the three differential signals, e.g., the difference between clot and blood (the absolute value of clotblood) and the difference between clot and wall (e.g., the absolute value of clot-wall), and the difference between wall and blood (e.g., the absolute value of wall-blood). Thus, in this example, different frequencies may be selected that may best differentiate between these materials.

[0068] Although FIGS. 9 A and 9B show testing at a frequency spectrum, in some cases just optimal frequencies may be used; each of these frequencies (e.g., test frequencies) may become an independent input. Any of the methods and apparatuses described herein may include one or more machine learning agents to enhance the pattern recognition indicating the presence of clot, blood, wall, etc. (including the type of clot or other characteristics). For example, identified key frequencies may be used as input to a machine learning agent, such as a classifier, such as an LVQ classifier which may classify multi-variable inputs into multiple categories using code-vectors trained on input data.

[0069] As mentioned above, any of the methods and apparatuses described herein may also or alternatively include ultrasound sensing, e.g., in addition to or instead of optical sensing. One or more ultrasound sensors may be used in the place of the optical sensors described above in reference to FIGS. 2A-2B, 3, 4, 7A-7D and 8. For example, described herein are ultrasound sensing apparatuses and method for analyzing material removed from the patient, including but not limited to obstructive material (e.g., clot material), as it travels through the removal catheter or other portion of the system, including blood suction and / or filtration portions. These ultrasound methods may help improve analysis accuracy and speed during removal of the clot material. In some cases, these methods and apparatuses may confirm the readings from the electrical (e.g., impedance) sensing and control described above. In some examples the methods and apparatuses described herein may include apparatuses and methods that detect clot material, and / or distinguish clot material from wall material, and / or determine the type or composition of clot material, and / or confirm the presence and location of clot material in a position relative to the aspiration opening and / or may automatically or semi-automatically activate aspiration through the lumen of thecatheter, using any of the techniques described above. In some cases, the methods and apparatuses may further include an ultrasound sensor and components (e.g., ultrasound transducer, acoustic lens, matching layer, etc.), including applying any of these techniques, following the aspiration of material to confirm the identity, size, weight, etc. of the of the clot material. Alternatively, in any of these apparatuses and methods ultrasound sensing may be used alone, without the use of electrical sensing (e.g., impedance) as described above.

[0070] Thus, any of these methods and apparatuses may include one or more (e.g., two or more) ultrasound sensors, that may be installed in-line with the catheter lumen. An ultrasound sensor may include an ultrasound transducer. The transducer may include a transducer and a receiver. Any appropriate ultrasound transducer may be used, particularly small or compact ultrasound transducers, such as piezoelectric ultrasound transducers, piezoelectric micromachined ultrasound transducers and capacitive micromachined ultrasound transducers. The transducers may include or may be used with, one or more ultrasound filters, lenses, etc. The apparatuses and methods described herein may include a lumen for coupling in-line with the suction lumen and / or catheter lumen of the aspiration catheter and / or may be integrated into the aspiration catheter.

[0071] In some examples the methods and apparatuses described herein may include an ultrasound transducer (e.g., ultrasound sensor) to image blood and blood-clot (e.g., obstructive material). The ultrasound frequency (or range of frequencies) used may be varied. In any of these methods and apparatuses one or more ultrasound sensors may be used. In some cases, the use of two ultrasound sensors, e.g., in locations a known distance apart, may enable the apparatus or method to estimate the speed that the clot travels in the lumen. The signal from each ultrasound sensor may allow estimation of the length of the clot, which, together with knowledge of lumen cross-section, can be used by the apparatus or method to calculate the volume of the clot and using estimated specific weight for clot allow calculating approximate clot weight. Thus, any of these methods and apparatuses may be configured to determine a weight and / or volume of the clot material.

[0072] These apparatuses described herein, including the catheters or other regions of the flow (e.g., suction line) path that is used to collect clot material and / or blood may be formed at least in part by one or more materials that is are transparent to the wavelength of interest for either or both optical and ultrasound sensors used in the apparatus, such as one or more of: quartz, polycarbonate and acrylic. This region may be referred to as a sensing chamber. For example, in any of these apparatuses the flow path may include a chamber having noncircular (e.g., rectangular) sides within which sensing may occur, to minimize distortion that may arise from circular tubing. In some cases, this may be configured as a cuvette.IDENTIFYING OCCLUDED SIDE BRANCHES

[0073] The methods and apparatuses described herein may be configured to detect a side branch of the pulmonary vasculature that is occluded with clot. In some cases, the branches of the vasculature may be so occluded that even contrast injections do not show the existence of the side branch, or where the entrance is located. This may result in incomplete removal of clot material. The methods and apparatuses described herein may be capable of, and in some cases adapted for, detection of occluded, including fully occluded, side branches. This information may allow for catheter tip placement for extraction of the clot material occluding the branch. Sensing the clot at the entrance to such an occluded vessel may allow the user to identify where that vessel is located and perform extraction.

[0074] For example, in procedure for removing clot material may include using a sensing / aspiration catheter to described herein to identify an occluded vessel and performing thrombectomy by aspirating the clot material from the occluded vessel.

[0075] These methods may include orienting one or more sensors (e.g., optical sensors, ultrasound sensors, etc.) on the distal end region of the device towards and / or against the vessel wall. The sensors may be similar to those described above, e.g., on the distal end region, including on the periphery of the aspiration opening or proximal and / or distal to the aspiration opening, or opposite the aspiration opening (on the radially opposite side of the aspiration opening). The apparatus may include one or more additional sensors that are positioned on a side-facing region portion. In some examples the sensors (e.g., side-facing one or more sensors) may be configured to be held against the wall of the vessel as the apparatus is moved within the vessel. For example, the apparatus may include a bending region and the sensors may be located on an outer region of this bending region, so that the sensors are positioned against the wall when the bending region is bent or curved. In some examples the sensors may be on a radially expandable region that may position the sensors against the wall. Thus, the sensor(s) may be moved with the catheter along the vessel wall to see if clot is sensed. This sliding may be done in either direction (e.g., towards a more distal location and / or towards a more proximal location). In examples in which the sensors are on the distal tip region, the tapered shape of the distal tip may be advantageous, as it may act as its own dilator.Examples

[0076] Examples of optical sensors and apparatuses including optical sensors, as well as methods of making, using and operating these apparatuses are described herein. These examples illustrate some, but not all, implementation of the concepts described herein. In general, an optically-enabled sensing system for a thrombectomy catheter may be configuredto correctly distinguish and / or classify material, e.g., tissue, at the end region of a catheter, including at or near an aspiration orifice and / or distal to the aspiration orifice, into blood, vessel wall, or clot. These apparatuses may be further configured to classify clot by type, such as (but not limited to): chronic vs. acute clot, density, resistance to resistance to fibrinolysis, etc. The methods and apparatuses may be configured to perform this classification without needing intimate contact between the tissue and the sensor (e.g., optical sensor). The distance range over which the sensing is best performed may be at least as far as the extraction zone for the aspiration of clot, which may be up to 10 mm away, or in some cases more, from the aspiration orifice (e.g., up to: 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, etc.).

[0077] In any of these methods and apparatuses, the tissue classification data may help navigate the thrombectomy catheter towards clot and to help determine and / or control when to perform aspiration. For example, during or after aspiration, the optical data collected by the optical sensors described herein may be used to determine if, when the flow is blocked, the blockage is entrained clot or is due to vessel wall blocking the flow. This may provide the clinician with data to inform their next procedural action. If the aspiration port is being blocked by vessel wall, the clinician can release the vacuum pressure and continue the procedure. If the aspiration port is being blocked by acute clot, the system may indicate that additional time to allow ingestion should be taken and / or additional or increased vacuum may be applied (e.g., stacked). If the aspiration port is being blocked by chronic clot, the catheter may be removed from the body to extract the clot, or some other mechanical means used to release the clot from the vasculature.

[0078] In any of these methods and apparatuses, the optical sensor information may be used on its own, or it may be combined with information from one or more other sensing modality, such as impedance sensing, that may provide independent measurements to increase confidence in classification of the material at or near the distal end of the catheter.

[0079] FIGS. 10A-10F illustrates examples of apparatuses including optical clot sensing. Any of these apparatuses may also include impedance sensing, e.g., by including one or more electrodes, as described above. In each of these examples a single optical sensor is shown, including a paired set of light emitters (e.g., LEDs, etc.) and light receivers (e.g., photodiode receivers), however mor than one optical sensors may be used. In some examples multiple light receivers may be paired with the same light emitter, or vice versa. In some cases, multiple optical sensors may be used with multiple optical frequencies (e.g., optical wavelengths). In some cases, the same optical receiver may be used with multiple differentemitters in which different emitters emit different wavelengths of light. Any appropriate wavelength or range of wavelengths may be used. Any of the optical sensors described herein may be used in combination with one or more optical components (filters, polarizers, diffraction gratings, lenses, mirrors, beamsplitters, prisms, etc.).

[0080] FIG. 10A shows one example of a catheter configured as an aspiration catheter 1013 that may include one or more optical sensors. In FIG. lOAthe aspiration catheter includes an offset side-facing opening (aspiration orifice or aspiration opening 1021); this aspiration orifice is on a lateral side that is tapered (e.g., having a taper angle that may be constant (e.g., between 10 degrees and 50 degrees, between 10 degrees and 40 degrees, between 15 degrees and 35 degrees, etc.) or may vary (e.g., increasing in the proximal direction). Any of the aspiration catheters described herein may instead be en face, e.g., on the distal-most surface of the catheter, unless the context specifies otherwise. The catheter may be any appropriate diameter (e.g., between 3 French and 30 French, etc.) and may be any appropriate length. These catheters may be used by themselves or in combination with one or more guidewires, guide catheters, etc.

[0081] FIGS. 10B-10F illustrate examples of different variations of optical sensors that may be used with an aspiration catheter similar to that shown in FIG. 10 A. For example, FIG. 10B shows the aspiration catheter including an optical sensor that is oriented within the aspiration lumen of the catheter so that the light emitter 1054 is emits light out of the aspiration opening to form an optical sensing region 1050 that extends lateral and slightly distally and proximally from the aspiration opening, as shown. A light receiver 1052 is positioned adjacent to the emitter in this example the light emitter and light receiver forming the optical sensor are connected via electrical connections 1056 to an optical sensing module (e.g., optical sensing circuitry 1017) at a proximal end region of the catheter. Thus, the emitter and receiver forming the optical sensing elements may be inside of the aspiration orifice and may be oriented to “look” slightly outside of the aspiration opening. The optical elements inside the aspiration catheter and facing out towards the aspiration orifice may restrict the signal to the orifice and to the immediate area just outside the orifice. The emitter and receiver may be embedded in the wall of the catheter and / or may be attached to the wall of the catheter.

[0082] FIG. 10C shows another example of an aspiration catheter in which the optical elements are positioned on the aspiration orifice rim, to best provide optical sensing data out into the extraction zone of the aspiration orifice. In this example, the light emitter 1054 is positioned across the aspiration opening from the light receiver 1052. The receiver and emitter may be positioned in any locations around the rim, including on opposite sides, or onthe same side, or in some cases adjacent to each other. For example, it may be particularly beneficial to have the emitter positioned between the 6 o’clock and the nine o'clock positions (with the 12 o’clock position being at the most proximal end) and the receiver between the 3 o’clock position and the six o'clock position, or vice versa (e.g., switching the emitter position with the receiver position). In some cases, the emitter may be between the 11 o’clock position and the 1 o’clock position and the receiver may be between the 5 o’clock position and the 7 o’clock position, or vice versa (e.g., switching the emitter position with the receiver position).

[0083] In any of these apparatuses the optical elements may be physically located proximally, e.g., back at the catheter handle, but coupled to the aspiration catheter distal end region, including the orifice, using fiber optic materials. In some cases, the optical fiber may be a single fiber or split into two (one for transmit, one for receive). Thus, in general where the specification indicates that the light emitter is on the rim or distal end region, this may refer to an actual source (e.g., LED) or to the output of a fiber optic coupled to the source, and the light receiver may refer to the actual receiver (e.g., photodiode) or to an input of a fiber optic coupled to the receiver. For example, FIG. 10D shows an example in which the optical sensing region is established by the outputs of optical fiber connections 1058, 1058’ that are separately coupled to a light receiver 1052 and light emitter 1054.

[0084] Any of these apparatuses may include one or more optical elements placed on the distal end region of the aspiration catheter to provide pre-knowledge of clot presence as the catheter is pushed and navigated towards it in the vasculature, as shown in FIG. 10E. In this example, the light emitter 1054 and light receiver 1052 are positioned distal to the aspiration orifice, on the catheter, which are connected via one or more electrical connections 1056 to the optical sensing circuitry 1017. The light emitter and receiver may be oriented to emit and receive light in the direction (e.g., in front of and / or overlapping with, as within the field of view of, the aspiration opening), so that the optical sensing region 1050 is positioned in front of the aspiration opening. In some cases, the optical sensing region may be moved (e.g., by rotating the optical sensor (e.g., light emitter and light sensor).

[0085] In some examples the optical sensor may be positioned on an accessory apparatus (e.g., accessory catheter, which in some examples may be a navigation catheter), as shown in FIG. 10F. In this example the optical elements are placed on an accessory catheter to allow independent motion of the optical sensing region with respect to the aspiration catheter. In this example the optical sensing catheter is shown exiting through the aspiration opening; in some cases, it may exit from the guidewire lumen / channel 1063. The optical sensing cathetermay be moved independently of the aspiration catheter or may be moved with the aspiration catheter.

[0086] In any of these methods and apparatuses, the light-emitter 1054 may be either wide-band or narrow-band. The photo-diode receiver 1052 may either be wide-band or narrow-band. In some cases, it may be preferably that at least one of the optical sensing elements is narrow-band in the area of the EM spectrum which best differentiates the tissue types of interest in the reflected spectrum.

[0087] As mentioned, any of these methods and apparatuses may include combinations of those shown above, as well as other locations not shown, such as on the walls of the aspiration catheter to determine if the shaft is up against a vessel wall.

[0088] In general, the optical sensing region may overlap with the extraction zone for clot aspiration, as shown in FIGS. 10B-10E. Thus, these two regions (extraction zone and sensing region), so once clot is detected in the sensing region it could be extracted through aspiration. This may be the most straightforward for user experience and system -level control. In some examples the optical sensing region 1060 may be solely within the extraction zone 1050. This could also be used to detect clot which can then be aspirated. It can also confirm clot vs. wall in the clogged-tip case. In some cases, the apparatus may be configured for optical sensing beyond the extraction zone. This may allow for pre-knowledge of clot location to help with navigation to the clot, however it may be unclear if clot can be extracted from that catheter position, although the use of another sensing modality, such as impedance-sensing electrodes on the rim, may provide additional information that may resolve this ambiguity. For example, FIG.11 shows an apparatus in which the extraction zone 1050 is slightly larger than the optical sensing region 1060.

[0089] The apparatuses described herein may be configured to scan for side branches as the device is advanced and / or retracted. For example, the controller may be configured to, on an ongoing basis, examine the optical and / or ultrasound properties of the side-facing sensors that are presumed to be in contact with the wall of the vessel and may indicate when the signal is within the range of clot material, potentially indicating a side branch that is occluded. The controller may be configured to scan automatically or semi -automatically (e.g., assisting the user in directing movement of the distal end region of the device).

[0090] Any of the apparatuses and methods described herein may include sensing (e.g., optical sensing) of clot material within virtually any portion of the apparatus, including in some examples, a blood return and / or collection portion. For example, any of these apparatuses may include or be part of a blood return circuit in which blood is removed from the patient, filtered or otherwise treated, and returned to the patient. For example, blood maybe removed from the patient using any of the aspiration catheters described herein, or any other aspiration catheter. The blood may be passed (e.g., pumped, aspirated, etc.) to a blood collection chamber and / or one or more filters for removal of clot material. This blood circuit may include one or more fluid (blood) lines for communicating between the catheter, pump, filter(s), collection chamber(s), etc. These lines may include one or more optical and / or electrical sensors (e.g., impedance sensors) for detecting clot material, as described herein. Any of these apparatuses may include one or more sensors for detecting clot material within a chamber, filter, pump, etc., including optical sensor as described herein.

[0091] FIG. 12 illustrates one example of an apparatus configured with blood return in which blood is removed from and returned to the patient 1201. The blood return circuit 1200 includes an aspiration catheter 1203 which may include one or more optical sensors, including at positions indicated 1205 in or on the aspiration catheter. In this example the aspiration catheter 1203 includes an optical sensor at the distal end region, at a region distal to the handle 1207 and at a region proximal to the handle 1207. The system 1200 may also include a fluidic connection to one or more of: a source of aspiration (e.g., aspiration power), one or more filters (e.g., blood / clot separation / filtering) and / or a de-airing (e.g., bubble removal) portion 1209. In the schematic shown in FIG. 12 the system 1200 also includes a blood return line 121 Ithat is arranged in-line with a filter 1213 and along which multiple optical sensors configured to detect clot 1217 are positioned, e.g., at one or more locations along the length.

[0092] Any of these apparatuses may include a controller, including one or more processors that may monito the optical data stream to determine if clot material is detected. If so, the apparatus may confirm that it is removed by filtration and / or may stop / pause delivery back into the body until the clot material has been removed, and the blood flow line is free of clot material.

[0093] All publications and patent applications mentioned in this specification are herein incorporated by reference in their entirety to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. Furthermore, it should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein and may be used to achieve the benefits described herein.

[0094] Any of the methods (including user interfaces) described herein may be implemented as software, hardware or firmware, and may be described as a non-transitory computer-readable storage medium storing a set of instructions capable of being executed bya processor (e.g., computer, tablet, smartphone, etc.), that when executed by the processor causes the processor to control perform any of the steps, including but not limited to: displaying, communicating with the user, analyzing, modifying parameters (including timing, frequency, intensity, etc.), determining, alerting, or the like. For example, any of the methods described herein may be performed, at least in part, by an apparatus including one or more processors having a memory storing a non-transitory computer-readable storage medium storing a set of instructions for the processes(s) of the method.

[0095] While various embodiments have been described and / or illustrated herein in the context of fully functional computing systems, one or more of these example embodiments may be distributed as a program product in a variety of forms, regardless of the particular type of computer-readable media used to actually carry out the distribution. The embodiments disclosed herein may also be implemented using software modules that perform certain tasks. These software modules may include script, batch, or other executable files that may be stored on a computer-readable storage medium or in a computing system. In some embodiments, these software modules may configure a computing system to perform one or more of the example embodiments disclosed herein.

[0096] As described herein, the computing devices and systems described and / or illustrated herein broadly represent any type or form of computing device or system capable of executing computer-readable instructions, such as those contained within the modules described herein. In their most basic configuration, these computing device(s) may each comprise at least one memory device and at least one physical processor.

[0097] The term “memory” or “memory device,” as used herein, generally represents any type or form of volatile or non-volatile storage device or medium capable of storing data and / or computer-readable instructions. In one example, a memory device may store, load, and / or maintain one or more of the modules described herein. Examples of memory devices comprise, without limitation, Random Access Memory (RAM), Read Only Memory (ROM), flash memory, Hard Disk Drives (HDDs), Solid-State Drives (SSDs), optical disk drives, caches, variations or combinations of one or more of the same, or any other suitable storage memory.

[0098] In addition, the term “processor” or “physical processor,” as used herein, generally refers to any type or form of hardware-implemented processing unit capable of interpreting and / or executing computer-readable instructions. In one example, a physical processor may access and / or modify one or more modules stored in the above-described memory device. Examples of physical processors comprise, without limitation, microprocessors, microcontrollers, Central Processing Units (CPUs), Field-ProgrammableGate Arrays (FPGAs) that implement softcore processors, Application-Specific Integrated Circuits (ASICs), portions of one or more of the same, variations or combinations of one or more of the same, or any other suitable physical processor.

[0099] Although illustrated as separate elements, the method steps described and / or illustrated herein may represent portions of a single application. In addition, in some embodiments one or more of these steps may represent or correspond to one or more software applications or programs that, when executed by a computing device, may cause the computing device to perform one or more tasks, such as the method step.

[0100] In addition, one or more of the devices described herein may transform data, physical devices, and / or representations of physical devices from one form to another. Additionally or alternatively, one or more of the modules recited herein may transform a processor, volatile memory, non-volatile memory, and / or any other portion of a physical computing device from one form of computing device to another form of computing device by executing on the computing device, storing data on the computing device, and / or otherwise interacting with the computing device.

[0101] The term “computer-readable medium,” as used herein, generally refers to any form of device, carrier, or medium capable of storing or carrying computer-readable instructions. Examples of computer-readable media comprise, without limitation, transmission-type media, such as carrier waves, and non-transitory-type media, such as magnetic-storage media (e.g., hard disk drives, tape drives, and floppy disks), optical-storage media (e.g., Compact Disks (CDs), Digital Video Disks (DVDs), and BLU-RAY disks), electronic-storage media (e.g., solid-state drives and flash media), and other distribution systems.

[0102] A person of ordinary skill in the art will recognize that any process or method disclosed herein can be modified in many ways. The process parameters and sequence of the steps described and / or illustrated herein are given by way of example only and can be varied as desired. For example, while the steps illustrated and / or described herein may be shown or discussed in a particular order, these steps do not necessarily need to be performed in the order illustrated or discussed.

[0103] The various exemplary methods described and / or illustrated herein may also omit one or more of the steps described or illustrated herein or comprise additional steps in addition to those disclosed. Further, a step of any method as disclosed herein can be combined with any one or more steps of any other method as disclosed herein.

[0104] The processor as described herein can be configured to perform one or more steps of any method disclosed herein. Alternatively or in combination, the processor can be configured to combine one or more steps of one or more methods as disclosed herein.

[0105] When a feature or element is herein referred to as being "on" another feature or element, it can be directly on the other feature or element or intervening features and / or elements may also be present. In contrast, when a feature or element is referred to as being "directly on" another feature or element, there are no intervening features or elements present. It will also be understood that, when a feature or element is referred to as being "connected", "attached" or "coupled" to another feature or element, it can be directly connected, attached or coupled to the other feature or element or intervening features or elements may be present. In contrast, when a feature or element is referred to as being "directly connected", "directly attached" or "directly coupled" to another feature or element, there are no intervening features or elements present. Although described or shown with respect to one embodiment, the features and elements so described or shown can apply to other embodiments. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed "adjacent" another feature may have portions that overlap or underlie the adjacent feature.

[0106] Terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. For example, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items and may be abbreviated as " / ".

[0107] Spatially relative terms, such as "under", "below", "lower", "over", "upper" and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is inverted, elements described as "under”, or "beneath" other elements or features would then be oriented "over" the other elements or features. Thus, the exemplary term "under" can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Similarly, the terms "upwardly","downwardly", "vertical", "horizontal" and the like are used herein for the purpose of explanation only unless specifically indicated otherwise.

[0108] Although the terms “first” and “second” may be used herein to describe various features / elements (including steps), these features / elements should not be limited by these terms, unless the context indicates otherwise. These terms may be used to distinguish one feature / element from another feature / element. Thus, a first feature / element discussed below could be termed a second feature / element, and similarly, a second feature / element discussed below could be termed a first feature / element without departing from the teachings of the present invention.

[0109] In general, any of the apparatuses and methods described herein should be understood to be inclusive, but all or a sub-set of the components and / or steps may alternatively be exclusive and may be expressed as “consisting of’ or alternatively “consisting essentially of’ the various components, steps, sub-components or sub-steps.

[0110] As used herein in the specification and claims, including as used in the examples and unless otherwise expressly specified, all numbers may be read as if prefaced by the word "about" or “approximately,” even if the term does not expressly appear. The phrase “about” or “approximately” may be used when describing magnitude and / or position to indicate that the value and / or position described is within a reasonable expected range of values and / or positions. For example, a numeric value may have a value that is + / - 0.1% of the stated value (or range of values), + / - 1% of the stated value (or range of values), + / - 2% of the stated value (or range of values), + / - 5% of the stated value (or range of values), + / - 10% of the stated value (or range of values), etc. Any numerical values given herein should also be understood to include about or approximately that value, unless the context indicates otherwise. For example, if the value " 10" is disclosed, then "about 10" is also disclosed. Any numerical range recited herein is intended to include all sub-ranges subsumed therein. It is also understood that when a value is disclosed that "less than or equal to" the value, "greater than or equal to the value" and possible ranges between values are also disclosed, as appropriately understood by the skilled artisan. For example, if the value "X" is disclosed the "less than or equal to X" as well as "greater than or equal to X" (e.g., where X is a numerical value) is also disclosed. It is also understood that the throughout the application, data is provided in a number of different formats, and that this data, represents endpoints and starting points, and ranges for any combination of the data points. For example, if a particular data point “10” and a particular data point “15” are disclosed, it is understood that greater than, greater than or equal to, less than, less than or equal to, and equal to 10 and 15 are considered disclosed as well as between 10 and 15. It is also understood that each unit between two particular unitsare also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

[0111] Although various illustrative embodiments are described above, any of a number of changes may be made to various embodiments without departing from the scope of the invention as described by the claims. Optional features of various device and system embodiments may be included in some embodiments and not in others. Therefore, the foregoing description is provided primarily for exemplary purposes and should not be interpreted to limit the scope of the invention as it is set forth in the claims.

[0112] The examples and illustrations included herein show, by way of illustration and not of limitation, specific embodiments in which the subject matter may be practiced. As mentioned, other embodiments may be utilized and derived there from, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Such embodiments of the inventive subject matter may be referred to herein individually or collectively by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept, if more than one is, in fact, disclosed. Thus, although specific embodiments have been illustrated and described herein, any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.

Claims

CLAIMSWhat is claimed is:

1. A method, the method comprising: receiving an optical data stream from one or more optical sensors on a distal end region of a catheter; determining, in an ongoing basis based on the optical data stream, if the distal end region is in proximity with blood, non-blood tissue or clot, based on a differential optical signal taken at different wavelengths; and outputting a state classification indicating if the distal end region of the catheter is in proximity with one or more of: blood, non-blood tissue or clot.

2. The method of claim 1, wherein the one or more optical sensors comprises an optical emitter and at least one optical detector.

3. The method of claim 1, further comprising adjusting the size of a window of time for collecting the differential optical signal of the optical data stream.

4. The method of claim 1, further comprising dynamically adjusting the size of the window of time, based on one or more of: the application of aspiration through the catheter, and / or the optical data stream.

5. The method of claim 1, further comprising adjusting suction through a lumen of the catheter based on the state classification output.

6. The method of claim 1, wherein the state classification includes indicating if the distal end region of the catheter is in proximity with a vessel wall tissue.

7. The method of claim 1, wherein the non-blood tissue comprises vessel wall.

8. A method of quantifying clot, the method comprising: optically sensing clot material within a suction lumen of a catheter; determining a volume of clot material within the suction lumen based on a velocity of the clot material, a duration of time during which the clot material was sensed, and a cross-sectional area of the suction lumen; and outputting the volume of clot material.

9. The method of claim 8, further comprising adjusting an applied negative pressure through the suction lumen based on the volume of clot material.

10. The method of claim 8, wherein optically sensing the clot material within the suction lumen of the catheter comprises sensing based on a differential optical signal taken at different wavelengths of light.

11. The method of claim 8, wherein determining the volume of clot material comprises sensing a leading edge of the clot material from a first optical sensor at a first location within the suction lumen and sensing the leading edge of the clot material from a second optical sensor at a second location within the suction lumen.

12. The method of claim 8, wherein optically sensing clot material comprises sensing clot material while applying suction through the suction lumen.

13. A system, the system comprising: an elongate flexible catheter comprising one or more optical sensors configured to detect an optical signal from a distal end region of the elongate flexible catheter; one or more processors; and a memory storing computer-program instructions, that, when executed by the one or more processors, perform a computer-implemented method comprising: receiving an optical data stream from one or more optical sensors on a distal end region of a catheter; determining, in an ongoing basis based on the optical data stream, if the distal end region is in proximity with blood, non-blood tissue or clot, based on a differential optical signal taken at different wavelengths; and outputting a state classification indicating if the distal end region of the catheter is in proximity with one or more of: blood, nonblood tissue or clot.

14. The system of claim 13, wherein the one or more optical sensors comprises an optical emitter and at least one optical detector.

15. The system of claim 13, wherein the computer-implemented method further comprises adjusting the size of a window of time for collecting the differential optical signal of the optical data stream.

16. The system of claim 13, wherein the computer-implemented method further comprises dynamically adjusting the size of the window of time, based on one or more of: the application of aspiration through the catheter, and / or the optical data stream.

17. The system of claim 13, wherein the computer-implemented method further comprises adjusting suction through a lumen of the catheter based on the state classification output.

18. The system of claim 13, wherein the state classification includes indicating if the distal end region of the catheter is in proximity with a vessel wall tissue.

19. The system of claim 13, wherein the non-blood tissue comprises vessel wall.

20. A system, the system comprising: an elongate flexible catheter comprising one or more optical sensors configured to detect an optical signal within a lumen of the elongate flexible catheter; one or more processors; and a memory storing computer-program instructions, that, when executed by the one or more processors, perform a computer-implemented method comprising: optically sensing clot material within a suction lumen of a catheter; determining a volume of clot material within the suction lumen based on a velocity of the clot material, a duration of time during which the clot material was sensed, and a cross-sectional area of the suction lumen; and outputting the volume of clot material.

21. The system of claim 20, wherein the computer-implemented method further comprises adjusting an applied negative pressure through the suction lumen based on the volume of clot material.

22. The system of claim 20, wherein optically sensing the clot material within the suction lumen of the catheter comprises sensing based on a differential optical signal taken at different wavelengths of light.

23. The system of claim 20, wherein determining the volume of clot material comprises sensing a leading edge of the clot material from a first optical sensor at a first location within the suction lumen and sensing the leading edge of the clot material from a second optical sensor at a second location within the suction lumen.

24. The system of claim 20, wherein optically sensing clot material comprises sensing clot material while applying suction through the suction lumen.

25. An apparatus for removing clot material, the apparatus comprising: an elongate flexible body; an aspiration opening at a distal end region of the elongate flexible body; an optical sensor positioned at a distal end region of the elongate flexible body on or adjacent to the aspiration opening, wherein the optical sensor comprises a light emitter and a light sensor; and one or more processors; and a memory storing computer-program instructions, that, when executed by the one or more processors, perform a computer-implemented method comprising: receiving an optical data stream from the optical sensors; determining, in an ongoing basis based on the optical data stream, if the distal end region is in proximity with blood, non-blood tissue or clot, based on a differential optical signal taken at different wavelengths; and triggering an outputting based on the determined proximity.

26. The apparatus of claim 25, wherein the optical sensor is positioned on a rim of the aspiration opening.

27. The apparatus of claim 25, wherein the optical sensor is distal to the rim of the aspiration opening.

28. The apparatus of claim 25, further comprising an impedance sensor on the distal end region.

29. The apparatus of claim 25, wherein the optical sensor forms an optical sensing region that is co-extensive with an extraction zone of the aspiration opening.

30. The apparatus of claim 25, wherein the optical sensor is at least partially within an aspiration lumen so that the optical sensor may sense out of the aspiration opening.

31. The apparatus of claim 25, wherein the optical sensor comprises one or more optical fiber connections forming an input and output for the optical sensor at the distal end region and coupling the input and output to the light emitter and a light sensor that are positioned at a proximal end of the apparatus.

32. The apparatus of claim 25, wherein the optical sensor is integrated into the distal end region.

33. The apparatus of claim 25, wherein the optical sensor is on a sensing catheter configured to extend distally from the aspiration opening.

34. The apparatus of claim 25, wherein the aspiration opening is positioned on a lateral side of the apparatus.

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