Suction catheter devices, and devices for perfusion

Abstract

Aspiration catheters for removing clot material from a patient, systems including these catheters, and methods of making and using these aspiration catheters may be configured to remove clot material in long, continuous strips that prevent the release of smaller clot fragments back into the vasculature. Also described herein are blood collection devices that may allow for safe and easy reperfusion of collected blood.

Description

[Technical field]

[0001] Claiming priority

[0001] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 334,075, entitled "ASPIRATION APPARATUSES FOR CLOT REMOVAL," filed April 22, 2022, and incorporated by reference in its entirety herein.

[0002]

[0002] 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. [Background technology]

[0003]

[0003] Devices and methods for removing unwanted tissue, such as clots, atheromas, fluid, polyps, cysts, or other obstructive material, from body lumens, such as blood vessels, ureters, bile ducts, or fallopian tubes, may use suction to draw the unwanted material into a collection device for removal from the body. In particular, various catheter devices have been developed for use in intraluminal and intravascular procedures to fragment and remove obstructive material, such as clots, thrombus, atheroma, and the like, from blood vessels.

[0004]

[0004] In many cases, the procedure may include fragmenting the material (e.g., clot material), often by injecting a fluid (saline or thrombolytic agent) into the vessel or treatment site to help break up the clot or tissue into particle sizes that can then be aspirated through the lumen of the treatment device or using a secondary catheter connected to a vacuum / suction source. Depending on the method of fragmentation and the hardness of the clot or tissue, particle size can vary. If the material is not completely fragmented, larger particles can accumulate in the catheter and block the aspiration lumen.

[0005]

[0005] However, these procedures may result in the release of smaller fragments back into the body, which is undesirable. Moreover, larger fragments may still clog the device, requiring even more involved surgery, increasing the risk of complications due to blood loss and extended operation time. Thus, there is a need for more efficient evacuation of material, such as blood clots, from vessels or body lumens. Furthermore, it would be desirable to have a device that allows for the aspiration of larger particles without requiring disruption of the clot material, thereby reducing operation time. Preferably, such an improved device would have a low profile to allow percutaneous use, and would be flexible and torqueable to allow use of the device in tortuous lumens. Moreover, such a device may preferably be designed to be placed over a guidewire. Summary of the Invention [Means for solving the problem]

[0006]

[0006] Described herein, among other things, are aspiration catheters for removing clot material from a patient, systems including these catheters, and methods of making and using these aspiration catheters, which may be configured to remove clots in longer continuous strips that prevent the release of smaller clot fragments back into the vessel, which may become problematic. The apparatus (e.g., devices and systems including, among other things, aspiration catheters) and methods described herein may be configured to include inlets (e.g., openings) that are configured and positioned to generate a buffer flow of fluid within the catheter that passes laterally through the aspiration into the catheter (in some cases, opposite to the aspiration) through the transverse aspiration opening, so as to impart a rotational momentum or force (e.g., rotational moment) to the clot as it is forced against the distal edge of the aspiration opening, resulting in the continuous shearing of the clot into long strips that may be simultaneously drawn into the aspiration lumen of the catheter. As such, these generally distal openings may be referred to herein as buffer flow openings. The buffer flow opening may be an opening into the vessel and / or the buffer flow opening may be an opening for fluid applied through a sub-lumen (e.g., separate from and / or running through and / or adjacent to the aspiration lumen). The methods and devices described herein are particularly well suited for removal of blood clots from larger vessels, including, but not limited to, pulmonary embolism, and thrombectomy, including peripheral thrombectomy.

[0007]

[0007] The aspiration catheters described herein provide a number of advantages over other aspiration catheters for removing blood clots. In particular, the methods and devices described herein may be configured to apply an entrained flow of fluid (e.g., blood or other fluid) that rotates (and / or everts) the clot within the vessel and pushes the clot against the proximal edge of the aspiration opening without significantly disrupting the clot. Unlike other devices that provide a "jet" of fluid (including blood) that is intended to disrupt and fragment the clot, the devices described herein, and in particular the buffer flow openings, are configured to prevent such disruption and fragmentation of the clot material. In particular, the features of the buffer flow openings described herein define certain parameter ranges that result in a gentler rotational motion on the clot that may result in cutting a strip of clot material from the clot. These ranges may include the longitudinal position of at least a portion of the buffer flow opening relative to the aspiration lumen, the size of the buffer flow opening relative to the aspiration lumen, the radial position of the buffer flow opening relative to the aspiration opening, and / or the number of buffer flow openings. Outside these ranges, as described herein, the aspiration catheter may not operate effectively, may not provide rotational force, may not cut strips of clot material as described herein, and / or may clog or form "lollipops" with clot material at the aspiration opening. The buffer flow openings described herein may be optimized to minimize the amount of blood lost during the aspiration procedure and / or to increase the rate at which clot material is removed.

[0008] For example, described herein are suction catheters (e.g., suction catheters) having one or more buffer flow openings, one or more of which are positioned distal to a center (along the longitudinal axis of the distal tip region). In general, the buffer flow openings may be radially opposed from the suction openings (may be radially offset from the longitudinal centerline of the suction openings by a value greater than 90 degrees, e.g., greater than 100 degrees, greater than 110 degrees, greater than 120 degrees, etc.). In general, the buffer flow openings may include at least one buffer flow opening that is opposed from the suction openings and positioned distal to the longitudinal midline of the suction openings. In some examples, the buffer flow openings may have a combined geometric center of all of the buffer flow openings that is within + / - 20% of the center of the longitudinal midpoint of the suction openings (and, in particular, the geometric center may be offset distally from the longitudinal midpoint of the suction openings).

[0009]

[0009] For example, a suction catheter device may include an elongate body having a suction lumen, a distal end region extending from the elongate body having a suction opening extending along a lateral length of the distal end region, and one or more buffer flow openings penetrating a face of the distal end region opposite the suction opening, the one or more buffer flow openings collectively having a geometric center along the lateral length of the distal end region that is within + / - 20% of a longitudinal center of the suction opening, and the one or more buffer flow openings configured to impart rotation (e.g., transfer rotational momentum) to the clot material, urge the clot material against a proximal edge of the suction opening, cut an elongate strip from the clot material, and entrain the elongate strip so that it is drawn proximally into the suction lumen.

[0010]

[0010] The suction catheter device may include an elongate body having a suction lumen, a distal end region extending from the elongate body having a suction opening extending along a lateral length of the distal end region, and one or more buffer flow openings penetrating a face of the distal end region opposite the suction opening and / or a distal end of the distal end region, the one or more buffer flow openings collectively having a geometric center along a lateral length of the distal end region distal to a longitudinal center of the suction opening, the one or more buffer flow openings being configured to impart a rotation (e.g., impart angular momentum) to the clot material, urging the clot material against a proximal edge of the suction opening, cut an elongate strip from the clot material, and entrain the elongate strip so that it is drawn proximally down into the suction lumen.

[0011]

[0011] The suction catheter device may include an elongate body having a suction lumen, a distal end region extending from the elongate body having a suction opening extending along a lateral length of the distal end region, and a number of between 2 and 20 (e.g., between 2 and 16, between 2 and 10, between 2 and 8, etc.) buffer flow openings penetrating a face of the distal end region opposite the suction opening, the number of buffer flow openings collectively having a geometric center along a lateral length of the distal end region that is at or distal to the longitudinal center of the suction opening, and the number of buffer flow openings configured to impart a rotation (e.g., impart angular momentum) to the clot material, urging the clot material against a proximal edge of the suction opening, cut an elongate strip from the clot material, and entrain the elongate strip so that the elongate strip is drawn proximally down into the suction lumen.

[0012] In some examples, the suction catheter device includes an elongate body having an aspiration lumen, a distal end region extending from the elongate body, the distal end region having an aspiration opening extending along a length of a side of the distal end region, and a plurality of between 2 and 20 (e.g., between 2 and 16, between 2 and 10, between 2 and 8, etc.) number of buffer flow openings through a face of the distal end region opposite the aspiration opening, the plurality of buffer flow openings being either longitudinally centered or distal to the longitudinal center of the aspiration opening. the plurality of buffer flow openings are configured to collectively have a geometric center along a lateral length of the distal end region located at a position adjacent the suction opening, a ratio of an area of ​​the suction opening to a combined area of ​​the plurality of buffer flow openings is between 12:1 and 14:1, and further, the plurality of buffer flow openings are configured to impart a rotation (e.g., impart angular momentum) to the clot material, urging the clot material against a proximal edge of the suction opening, cut an elongated strip from the clot material, and entrain the elongated strip as it is pulled proximally down into the suction lumen.

[0013]

[0013] In any of these devices, the distal end region may be configured as a distal tip coupled to the elongate body. The distal end region may include a suction opening and one or more buffer flow openings.

[0014]

[0014] In general, the collective geometric center of the one or more buffer flow openings may be within + / - 10% of the longitudinal center of the suction opening, and in particular may be distal to the longitudinal center of the suction opening. For example, the collective geometric center of the one or more buffer flow openings may be at the longitudinal center of the suction opening or distal to the longitudinal center. In some examples, the buffer flow openings may include at least one opening that is distal to the longitudinal center. For example, at least one buffer flow opening of the one or more buffer flow openings may be distal to the longitudinal center of the suction opening.

[0015] Any number of buffer flow openings may be used, including 1, 2, 3, 4, 5, 6, 7, 8, etc. For example, the one or more buffer flow openings may comprise a number between 2 and 8 buffer flow openings.

[0016] Any of the devices described herein may include a surface extending from the catheter and / or from the distal end region that may prevent clogging of the buffer flow opening. The surface may be configured as a protrusion and / or as a shroud. For example, any of these devices may include a shroud extending from an outer surface of the elongate body opposite the suction opening distal to the buffer flow opening, the shroud configured to prevent clot material from entering the buffer flow opening. In some cases, the shroud may be expandable, inflatable, etc. In some cases, the shroud or protrusion may be part of a lumen (e.g., a guide lumen or diagnostic catheter lumen, etc.). In some cases, the shroud or protrusion may be configured to prevent clots (distal to the tip) from extending back and into the buffer flow opening. In some instances, the same or a different shroud may be configured to prevent the buffer flow opening from sticking to the lumen wall (e.g., the vessel wall).

[0017] As noted, generally, the buffer flow openings may be positioned radially opposite from the suction openings, and in some cases, the buffer flow openings may be rotationally positioned between 90 and 180 degrees (e.g., between 90 and 145 degrees, between 90 and 180 degrees, etc.) from a longitudinal centerline through the suction openings.

[0018] Any of these devices may include a guide or navigation lumen extending adjacent to the aspiration lumen along the distal end region opposite the aspiration opening. This guide or navigation lumen (collectively referred to herein as navigation lumens) may be configured to receive a guide catheter or guidewire. In some cases, the guide or navigation lumen may be configured to receive a diagnostic catheter that may extend distally out of the aspiration catheter.

[0019] In any of these examples, the buffer flow opening may pass through and / or be blocked or shielded by the navigation lumen; in some examples, the buffer flow opening may be opened / closed by extending or removing an elongated member, such as a diagnostic catheter, within the lumen. When the diagnostic catheter is extended distal to the buffer flow opening, the opening may be partially or completely closed or blocked by the diagnostic catheter, allowing the buffer flow opening to be turned "off" or "on" by longitudinally repositioning the diagnostic catheter. For example, one or more buffer flow openings may extend through the navigation lumen, such that the buffer flow opening may be opened or closed by passing an elongated member through the navigation lumen. Alternatively, in some examples, the buffer flow opening may be configured to be open regardless of the position of the diagnostic catheter. In any of the devices described herein, the profile of the navigation lumen may be configured to protect the buffer flow opening and prevent the buffer flow opening from becoming clogged or blocked by clot material and / or the lumen wall. In some instances, the profile of the navigation lumen may be configured to help direct the fluid flow through the buffer flow openings, e.g., so that the fluid flow more effectively imparts rotation to the clot material within or adjacent to the aspiration opening. For example, in some cases, the one or more buffer flow openings may include two or more buffer flow openings disposed on opposite sides of the navigation lumen.

[0020] Any of the apparatus described herein are configured such that flow through the buffer flow openings entrains fluid in the aspiration lumen down the length of the aspiration lumen and imparts rotation (e.g., angular momentum) to the clot material to strike the proximal end / edge of the aspiration device. For example, any of these apparatus (e.g., devices, systems, etc.) may be configured such that the open surface area of ​​the aspiration openings compared to the sum of the open surface areas of the buffer flow openings is between about 10:1 and 18:1 (e.g., 10:1 and 17:1, 10:1 and 16:1, etc.). For example, in some instances, the ratio of the area of ​​the aspiration opening to the combined area of ​​the one or more buffer flow openings is between 10:1 and 16:1. In some instances, the ratio of the area of ​​the aspiration opening to the combined area of ​​the one or more buffer flow openings is between 12:1 and 14:1. Outside of these ratios, the apparatus may not operate efficiently and may take substantially longer to aspirate the clot.

[0021]

[0021] In general, the buffer flow opening may be configured to impart a rotation to a clot positioned within or adjacent to the lateral and / or tapered suction opening. This angular momentum may result in pushing the clot material against the proximal edge of the suction orifice, thus cutting the clot material; in particular, the angular momentum may cut the clot material into relatively long and thin strips while controlling the clot's motion. In large vessels, this may result in the clot rotating to hit the proximal edge of the suction opening. However, even in smaller vessels, the rotational momentum, while not rotating the clot due to vessel size constraints, may instead push the clot material to hit the suction opening in a manner similar to a typewriter carriage, for example, by pushing the clot material axially along the suction orifice edge in a distal to proximal direction, and then moving the clot material from proximal to distal, and repeating the cutting between distal and proximal. This motion, which may be the result of a combination of suction force through the suction opening as well as rotational forces (e.g., rotational moment) imparted by flow from the buffer flow opening, repeats until the clot is small enough to pass completely through the suction lumen.

[0022]

[0022] As noted above, any of these devices may include a displacement protrusion (e.g., a shroud) extending from an outer surface of the distal end region configured to displace an outer opening of one or more buffer flow openings from the wall of the vessel into which the distal end region is inserted.

[0023] In general, the distal end region of the device may be tapered on at least the lateral length of the distal end region including the suction opening such that the proximal outer edge region of the suction opening against which clot material is forced and turned (or everted) may be larger than the distal edge region, e.g., the suction opening may be wider at the proximal end than at the distal end.

[0024]

[0024] In general, the suction opening may be reinforced either or both around the periphery of the opening and / or radially around the distal tip. For example, the suction opening may include a reinforced lip region. The suction opening may be enlarged and / or include structural reinforcement (such as wires). Thus, the suction opening may include a reinforced lip region surrounding at least the proximal edge of the suction opening. Although the reinforcing structure may strengthen the lip region of the suction opening, the suction opening may still have an atraumatic outer surface that allows for advancement of the device within the vessel with the suction orifice effectively open without cutting or damaging the vessel wall. Alternatively or additionally, in some embodiments, the suction orifice may be covered, for example, by an elastic membrane that deflects inwardly and / or radially as suction is applied and the clot enters the orifice. In embodiments with the suction orifice covered, the suction force required to expose the suction orifice is less than the force to entrain fluid through the buffer flow opening.

[0025]

[0025] Although the suction opening is generally atraumatic (e.g., configured so as not to cut or catch on the vessel wall), in some instances the suction opening includes a cutting edge or surface at least at the proximal edge of the suction opening, preferably in a lip region away from the sides of the suction opening. For example, the suction opening or at least the proximal end region may include a cutting surface that is recessed relative to the outer surface and edge, which may be rounded or atraumatic. Alternatively or additionally, the proximal edge region may be thinner than the more lateral and / or distal edge regions of the suction opening, which may aid in cutting clot material that is forced against the proximal edge region.

[0026] Any of the devices described herein may include one or more sensors for detecting the presence of clot material, including detecting that a clot is still present at the aspiration opening and / or within the lumen of the aspiration catheter. Any of these devices may include a clot sensor in communication with the aspiration opening and / or configured to detect clot material within the distal end region.

[0027] In any of the devices described herein, the buffer flow opening may include a distal opening at a distal end of the device. The distal end opening may be spaced from the buffer flow opening in the sidewall of the device.

[0028]

[0028] For example, a suction catheter device is described herein comprising an elongate body having a suction lumen, a distal end region extending from the elongate body having a suction opening extending along a tapered length of a side of the distal end region, and a plurality of buffer flow openings penetrating a side of the distal end region opposite the suction opening, at least one of the plurality of buffer flow openings being distal to a longitudinal center of the suction opening, the suction opening being configured such that a diameter of the suction lumen at a distal edge of the suction opening is 40% or more of a diameter of the suction lumen at a proximal edge of the suction opening, and the plurality of buffer flow openings are configured to form a region of buffer flow within the suction lumen opposite the suction opening to apply a rotational force to clot material.

[0029]

[0029] In any of the devices described herein, the multiple buffer flow openings may comprise between 2 and 20 buffer flow openings. The devices described herein may include a navigation channel having a lumen extending into the aspiration lumen and configured to at least partially occlude the multiple buffer flow openings. The multiple buffer flow openings may be positioned between 60 degrees and 120 degrees from a longitudinal centerline through the aspiration opening. Any of these devices may include a navigation channel with a lumen extending adjacent to the aspiration lumen along a distal end region opposite from the aspiration opening. In any of these devices, one or more additional buffer flow openings extend through the navigation lumen. The multiple buffer flow openings may include two or more buffer flow openings disposed on either side of the navigation lumen.

[0030] The navigation lumen may be configured with a distal end opening within the aspiration lumen proximal to the distal tip region of the lumen. The ratio of the area of ​​the aspiration opening to the combined area of ​​the plurality of buffer flow openings may be between 10:1 and 16:1. In some examples, the ratio of the area of ​​the aspiration opening to the combined area of ​​the plurality of buffer flow openings is between 12:1 and 14:1.

[0031]

[0031] The suction opening may include a reinforced lip region surrounding at least a proximal edge of the suction opening. The suction opening may be wider at the proximal end than at the distal end.

[0032] Any of the catheters described herein may include a hold-up region at the distal end of the aspiration lumen, distal to the aspiration opening.

[0033]

[0033] For example, a suction catheter device may include an elongate body having a suction lumen, a distal end region extending from the elongate body having a suction opening extending along a tapered length of a side of the distal end region, and a plurality of buffer flow openings penetrating a side of the distal end region opposite the suction opening, at least one of the plurality of buffer flow openings being distal to a longitudinal center of the suction opening, the suction opening being configured such that a diameter of the suction lumen at a distal edge of the suction opening is 40% or more of a diameter of the suction lumen at a proximal edge of the suction opening, and the plurality of buffer flow openings are configured to form a buffer flow region within the suction lumen opposite the suction opening and to apply a rotational force (e.g., an angular force) to the clot material to urge the clot material against the proximal edge of the suction opening and cut an elongate strip from the clot material without fragmenting the clot material.

[0034] The buffer flow openings may be holes formed through the sidewall of the distal end region (distal tip) perpendicular through the distal region between the outer and inner surfaces, or in some cases, the buffer flow openings may be oriented to direct the flow slightly (e.g., proximally). Generally, the devices and methods described herein may be configured to have buffer flow openings through the sidewall of the distal end region of the aspiration catheter, but any of the methods and devices described herein may include an outlet for the buffer flow opening opposite from the aspiration opening described herein, but the inlet for the buffer flow opening may be located more proximally, e.g., proximal to the distal tip region. Generally, these devices may be configured to draw blood from the lumen in which the device is positioned. In some instances, the device may be configured to apply fluid (e.g., blood, saline, etc.) from an external source. For example, any of the methods and devices described herein may be configured to apply fluid from a fluid line to a buffer flow opening, referred to herein as the outlet of the buffer flow opening (e.g., the inlet may be proximal, including outside the patient, and the outlet may be coupled to a fluid line extending proximally).

[0035]

[0035] Generally, methods of using devices such as those described above are described herein. For example, methods are described herein that include rolling clot material against a suction opening when removing clot material. In some examples, methods include a method of removing clot material, the method including positioning an elongated suction opening of an aspiration catheter adjacent a clot within a lumen of a vessel, the suction opening extending to a side of a distal end region of the aspiration catheter, the aspiration catheter further comprising one or more buffer flow openings extending through a face of the distal end region opposite the suction opening, and applying suction through an aspiration lumen of the aspiration catheter to draw the clot and fluid from the suction opening into the aspiration catheter and through the one or more buffer flow openings, the one or more buffer flow openings configured relative to the suction opening such that a flow of fluid into the aspiration catheter imparts a rotational force (e.g., angular force) to the clot, urging the clot against a proximal edge of the suction opening, cutting the clot against the proximal edge, and everting the clot against the suction opening.

[0036]

[0036] Applying suction may include applying suction of greater than 10 mmHg (e.g., a difference between atmospheric pressure and the pressure in the catheter of approximately 10 mmHg or more). Applying suction may include drawing fluid through one or more buffer flow openings that collectively have a geometric center that is within 10% of the longitudinal midpoint of the suction opening, that is longitudinally centered or distal to the longitudinal center (e.g., at least one of the buffer flow openings is positioned distal to the longitudinal center of the suction opening, etc.). In some examples, applying suction includes drawing fluid through one or more buffer flow openings that collectively have a geometric center that is longitudinally centered or distal to the longitudinal center of the suction opening, that is longitudinally centered or distal to the longitudinal midpoint of the suction opening.

[0037] Any of these methods may include cutting an elongated strip from the clot material from the clot as the clot is forced against the proximal edge of the suction opening and translated (everted or moved / axially reciprocated / moved back and forth) relative to the suction opening. The one or more buffer flow openings may be configured to draw fluid into the suction catheter such that the fluid entrains the strip of clot material that is cut as the clot material is forced against the proximal edge of the suction opening.

[0038]

[0038] Applying suction through the suction catheter to draw fluid through one or more buffer flow openings may include entraining flow down the length of the suction lumen without substantially disrupting the cut clot within the suction lumen.

[0039] In any of these methods, the clot outside the aspiration catheter may be rolled and / or everted by flow urged by the buffer flow opening and the aspiration opening. Everting the clot against the aspiration opening may include rolling the clot within the vessel against the aspiration opening of the aspiration catheter.

[0040] As noted, any of these devices and methods may include the use of one or more clot detection sensors, so any of these methods may also include automatically ceasing or reducing suction when no clot is detected adjacent the suction opening or in the distal end region.

[0041] Also described herein are methods for removing a blood clot in relatively long strands. Unlike the systems described above which may disrupt the blood clot, including through the use of one or more "jets" of fluid applied before, during, or after aspiration, the methods and devices described herein may instead be configured to remove strips of the blood clot in relatively long lengths. For example, a method of removing clot material is described herein that includes positioning an elongated suction opening of an aspiration catheter adjacent a clot within a lumen of a vessel, the suction opening extending to a side of a distal end region of the aspiration catheter, the aspiration catheter further comprising one or more buffer flow openings extending through a face of the distal end region opposite the suction opening; and applying suction through the aspiration lumen of the aspiration catheter to draw the clot against a proximal edge of the suction opening of the aspiration catheter while drawing fluid through the one or more buffer flow openings, whereby a strip of clot material is cut by the proximal edge of the aspiration catheter, the buffer flow openings being configured such that fluid drawn into the aspiration catheter through the one or more buffer flow openings entrains the strip of clot material to draw the strip of clot material proximally down the aspiration catheter without substantially disrupting the strip of clot material.

[0042] In any of these methods, positioning the elongated suction opening may include spacing one or more buffer flow openings from a wall of the vessel.

[0043] Any of these methods may include applying suction by applying a pressure greater than 10 mmHg (e.g., greater than 10 mmHg difference over atmospheric and / or intravascular pressure). In general, the buffer flow openings may be positioned or configured such that at least one buffer flow opening (e.g., or at least two buffer flow openings, at least three buffer flow openings, at least half of the buffer flow openings, etc.) is distal to the longitudinal midpoint of the suction opening. In some examples, applying suction may include drawing fluid through one or more buffer flow openings that collectively have a geometric center that is at or distal to the longitudinal center, that is within + / -20% (e.g., + / -10%, etc.) of the longitudinal midpoint of the suction opening. Applying suction may include drawing fluid through one or more buffer flow openings that collectively have a geometric center that is at or distal to the longitudinal midpoint of the suction opening. In any of these devices and methods, at least one buffer flow opening may be distal to the longitudinal midpoint of the suction opening to provide a rotational force, as described herein.

[0044] Any of these methods may include cutting a long thin strip of clot material from the clot as the clot is forced against the proximal edge of the suction opening and inverted against the suction opening.

[0045]

[0045] The one or more buffer flow openings may be configured relative to the suction opening such that flow of fluid into the suction catheter imparts a rotational force to the clot, urging it against the proximal edge of the suction opening. The methods described herein may include automatically ceasing or reducing suction when no clot material is detected adjacent the suction opening or within the distal end region.

[0046]

[0046] Also described herein are suction collection and reperfusion devices and methods of using them to aspirate clot material from the vasculature in a manner that safely simplifies the return of aspirated blood to the patient and minimizes exposure of the blood to low negative pressure. These devices typically include an assembly including at least an upper chamber and a lower chamber. The upper chamber may receive and maintain a vacuum when connected to an aspiration catheter to allow for aspiration. Additionally, the upper chamber may include a filter element that may filter clot material removed from the patient. In some embodiments, the upper chamber may be separated into two chambers that are fluidly connected via tubing. In other embodiments, the filter element may be located in the lower chamber between the reperfusion valve and the reperfusion line. Blood may be transferred to the lower chamber in a manner that does not damage the blood or induce bubble formation. The devices and methods of using the devices may allow for immediate or near-immediate return of blood for reperfusion without requiring multiple transfers and without delaying the aspiration procedure.

[0047] For example, a device for perfusion of collected blood and blood clots is described herein, the device including an upper chamber, a lower chamber, a filter element in the upper and / or lower chamber configured to capture blood clots, a vacuum inlet into the upper chamber and configured to couple to a vacuum source, a suction inlet into the upper chamber configured to couple to an aspiration line through a suction valve, a reperfusion outlet from the lower chamber configured to couple to a reperfusion line (and flow from the reperfusion outlet to the reperfusion line may be controlled through the reperfusion valve), and a vacuum release valve in fluid communication with the upper chamber, the reperfusion valve configured to open when the vacuum release valve opens. In some examples, the reperfusion valve is configured to open only when the vacuum release valve opens.

[0048] Any of these devices may include a fine filter in fluid communication with the reperfusion outlet. The coarse filter may be configured to be manually removed from the upper chamber by opening the top of the upper chamber.

[0049] Any of the devices for perfusion of collected blood described herein may include an impermeable partition between the upper and lower chambers and one or more partition valves configured to form an opening through the impermeable partition. The partition valves may be configured to automatically open (e.g., when the pressure between the upper and lower chambers is normalized to approximately the same pressure and when the weight of blood in the upper chamber exceeds the cracking pressure of the one or more valves). For example, the one or more partition valves may comprise one or more umbrella valves configured to open when the fluid pressure impinging on the valve exceeds the cracking pressure. Alternatively, in some examples, the apparatus may be configured such that the partition valve(s) are actively controlled to open, for example, when the system detects a sufficient amount of blood in the upper chamber and when the pressure difference between the upper and lower chambers is approximately normalized (by directly detecting pressure in the upper and / or lower chambers or by detecting that a vacuum release valve in the upper chamber is opened). In some examples, the apparatus may include a processor configured to coordinate the opening of the partition valve and the vacuum release valve.

[0050] In any of these examples, the lower chamber may include a pressure regulator opening. In some examples, the pressure regulator opening is configured to vent to atmosphere. Alternatively or additionally, the lower chamber may be configured to maintain a lower pressure, such as atmospheric pressure, such that, for example, the upper and lower chamber pressures can be quickly normalized and the upper chamber can maintain some negative pressure (e.g., vacuum) even when transferring blood from the upper chamber to the lower chamber.

[0051]

[0051] In general, the pressure in the lower chamber may be controlled to prevent or minimize bubble formation, and the reperfusion valve may be configured not to open until the pressure in the lower chamber is approximately atmospheric pressure.

[0052]

[0052] In any of these devices, the device may be configured such that blood, and in particular trapped blood clot material, may be directly visualized. For example, the upper and lower chambers may be configured to allow direct visualization of blood through the walls of the upper and lower chambers. In some examples, the device may include a separate filtration (e.g., coarse filtration) chamber upstream of the upper chamber that is configured (e.g., in a planar configuration) to allow direct visualization of the clot material as it is filtered out. The filtration chamber may be opened to allow removal of the clot material from the coarse filter without collapsing the device.

[0053] Any of these devices may include a reperfusion fluid line in fluid communication with the reperfusion outlet through a reperfusion valve. Similarly, any of these devices may include a vacuum source coupled to a vacuum inlet.

[0054] In some examples, the device for perfusion of collected blood includes separate (partitioned) upper and lower chambers, each of which may be pressure controlled to allow transfer from the upper chamber to the lower chamber by gravity. The lower chamber may be configured to allow easy perfusion of the collected blood back to the patient, directly or indirectly, including by collection in a syringe or other container for later perfusion.

[0055]

[0055] For example, a device for perfusion of collected blood comprises an upper chamber, a lower chamber, an impermeable partition between the upper and lower chambers, a partition valve configured to form an opening through the impermeable partition, a vacuum inlet entering the upper chamber and configured to connect to a vacuum source, a suction inlet entering the upper chamber, a reperfusion outlet exiting the lower chamber, and a pressure regulating opening entering the lower chamber configured to maintain a pressure in the lower chamber greater than the pressure in the upper chamber and above the bubble formation pressure of the blood, the partition valve configured to open to allow blood to flow from the upper chamber into the lower chamber.

[0056] Any of these devices may include a coarse filter in fluid communication with the upper chamber. The coarse filter may be configured to have pores sized to limit the ability of blood clots to pass through, but allow blood (including cells, e.g., red blood cells, etc.) to pass unimpeded. In some examples, the coarse filter may be a mesh and / or have pores large enough to allow liquid blood to pass easily, but small enough to prevent clot material from passing through. In some examples, the coarse filter is removable to allow manual clearance of blood clots.

[0057] As noted above, in some examples, the device includes a clot collection and visualization chamber equipped with a coarse filter and in fluid communication with the upper chamber through the suction inlet.

[0058]

[0058] The pressure adjustment opening in the lower chamber may, in some examples, be one or more openings to the atmosphere. The openings may be direct or may be covered with a filter to prevent contamination. Alternatively, in some examples, the lower chamber may include a connection to a vacuum source (or a second vacuum source), which may maintain the lower chamber at a pressure closer to atmospheric pressure compared to the upper chamber, while still remaining above pressures that would result in increased bubble formation. In some examples, the pressure adjustment opening comprises a valve that controllably connects the lower chamber to a negative pressure source.

[0059] Any of these devices may include one or more pressure sensors, for example in the upper and / or lower chambers. Alternatively, in some instances, no additional sensors are included.

[0060] The apparatus may include a vacuum release valve in fluid communication with the upper chamber and / or the lower chamber. As mentioned, the one or more partition valves may comprise one or more umbrella valves configured to open when fluid pressure impinging on the valve exceeds a crack pressure.

[0061]

[0061] In general, the upper and lower chambers may be configured to allow direct visualization of blood through the walls of the upper and lower chambers. The device may include a reperfusion fluid line in fluid communication with a reperfusion outlet through a reperfusion valve. The device may include a fine filter in fluid communication with the reperfusion line. Any of these devices may include a vacuum source coupled to a vacuum inlet.

[0062]

[0062] For example, a device for perfusion of collected blood may include an upper chamber, a lower chamber, an impermeable partition between the upper and lower chambers, one or more partition valves configured to form an opening through the impermeable partition, a coarse filter in fluid communication with the upper chamber, a vacuum inlet entering the upper chamber and configured to couple to a vacuum source, a vacuum release valve in the upper chamber, a suction inlet entering the upper chamber, a suction valve between the suction inlet and a suction line extending from the suction inlet, a reperfusion outlet in the lower chamber and configured to be placed in fluid communication with the reperfusion fluid line by a reperfusion valve, a pressure regulating opening entering the lower chamber configured to maintain a pressure in the lower chamber above the pressure of the upper chamber and above a bubble formation pressure of the blood, and a fine filter in fluid communication with the reperfusion line, the one or more partition valves configured to open when the vacuum release valve opens to allow blood to flow from the upper chamber into the lower chamber.

[0063]

[0063] Also described herein is a method of reperfusing blood during a clot removal procedure, the method including charging an upper chamber of a reperfusion system with a vacuum; opening a suction valve, drawing blood from a patient into the upper chamber through a suction inlet and filtering clot material from the blood using a coarse filter in fluid communication with the upper chamber; collecting the blood from the upper chamber into the lower chamber after filtering the clot material, wherein collecting blood from the upper chamber into the lower chamber includes opening a partition valve separating the upper chamber from the lower chamber when the vacuum in the upper chamber is released to approximately the pressure in the lower chamber, whereby the blood drains from the upper chamber into the lower chamber by gravity; opening a reperfusion valve in fluid communication with the lower chamber after the pressure in the lower chamber is approximately atmospheric pressure; and returning the blood from the lower chamber into the patient's body.

[0064] In any of these methods, opening the partition valve may include controlling the partition valve to open when the pressure in the upper chamber is approximately equal to the pressure in the lower chamber. In some examples, opening the partition valve may include automatically opening the partition valve when the pressure in the upper chamber is approximately equal to the pressure in the lower chamber and the weight of the fluid on the partition valve is greater than a crack pressure for the partition valve. Collecting blood from the upper chamber into the lower chamber may include releasing pressure in the upper chamber by opening a vacuum release valve.

[0065] Any of these methods may include filtering the blood through a fine filter before returning the blood from the lower chamber back into the patient's body. Any of these methods may include removing clot material from the coarse filter. Any of these methods may include recharging the upper chamber with a vacuum, thereby allowing further suction after blood has been collected in the lower chamber.

[0066] Charging the upper chamber of the reperfusion system with a vacuum may include operating a vacuum source coupled to the upper chamber through a vacuum inlet. In some examples, the method may include leaving the vacuum source on continuously while opening the suction valve, collecting blood, and opening the reperfusion valve.

[0067]

[0067] For example, a method of reperfusing blood during a clot removal procedure may include charging an upper chamber of a reperfusion system with a vacuum, opening a suction valve, drawing blood from the patient into the upper chamber through a suction inlet, filtering clot material from the blood using a coarse filter in fluid communication with the upper chamber, normalizing pressure between the upper and lower chambers, opening a partition valve separating the upper and lower chambers so that blood from the upper chamber flows into the lower chamber, opening, recharging the upper chamber with a vacuum to allow further suction, opening a reperfusion valve in fluid communication with the lower chamber, and returning blood from the lower chamber into the patient's body.

[0068] The lower chamber may be maintained at atmospheric pressure. The lower chamber may be maintained at a pressure between atmospheric pressure and the bubble forming pressure of blood (e.g., 600 mmHg). Any of these methods may include removing the clot material from a coarse filter.

[0069]

[0069] All of the methods and apparatus described herein, in any combination, are contemplated herein and can be used to achieve the benefits described herein.

[0070] A better understanding of the features and advantages of the methods and apparatus described herein will be obtained with reference to the following detailed description and accompanying drawings that set forth illustrative embodiments. [Brief description of the drawings]

[0071] [Figure 1]

[0071] FIG. 1 illustrates an example of a suction catheter as described in this specification. [Diagram 2]

[0072] FIG. 2A is a transparent view of an example of a distal end region of a catheter, such as an aspiration catheter.

[0073] FIG. 2B is a non-transparent view of the distal end region of the aspiration catheter of FIG. 2A. [Diagram 3]

[0074] FIG. 3A is a top view of another example of a distal end region of an aspiration catheter.

[0075] FIG. 3B is a perspective view of the distal end region of the suction catheter, illustrating the flow lines entering the suction catheter as suction is applied.

[0076] FIG. 3C is a side cross-sectional view of the aspiration catheter shown in FIG. 3B. [Figure 4]

[0077] FIG. 4A shows an aspiration catheter without buffer flow openings, demonstrating clogging of clot material ("lollipoping") at the aspiration openings on the sides of the aspiration catheter.

[0078] FIGURE 4B is a diagram showing the effect of a buffer flow opening on clot aspiration, illustrating the application of a rotational force to the clot material, which forces the clot material against the proximal opening edge of the suction opening, forming a long strip of clot that enters the suction lumen for removal from the body.

[0078] FIGURE 4C is a diagram showing the effect of a buffer flow opening on clot aspiration, illustrating the application of a rotational force to the clot material, which forces the clot material against the proximal opening edge of the suction opening, forming a long strip of clot that enters the suction lumen for removal from the body. [Diagram 5]

[0079] FIG. 5A illustrates removal of a model clot using an example aspiration catheter including a buffer flow opening as described herein. A rotational force is applied to the clot through the aspiration lumen based on the configuration of the buffer flow opening, causing the clot to be pushed against the proximal edge region of the aspiration opening, including rotating (and everting) the clot to allow for cutting of a strip of clot model material. FIG. 5B illustrates removal of a model clot using an example aspiration catheter including a buffer flow opening as described herein. A rotational force is applied to the clot through the aspiration lumen based on the configuration of the buffer flow opening, causing the clot to be pushed against the proximal edge region of the aspiration opening, including rotating (and everting) the clot to allow for cutting of a strip of clot model material. FIG. 5C illustrates removal of a model clot using an example aspiration catheter including a buffer flow opening as described herein. A rotational force is applied to the clot through the aspiration lumen based on the configuration of the buffer flow opening, causing the clot to be pushed against the proximal edge region of the aspiration opening, including rotating (and everting) the clot to allow for cutting of the strip of clot model material. FIG. 5D illustrates removal of a clot model using an example aspiration catheter including a buffer flow opening as described herein. A rotational force is applied to the clot through the aspiration lumen based on the configuration of the buffer flow opening, causing the clot to be pushed against the proximal edge region of the aspiration opening, including rotating (and everting) the clot to allow for cutting of the strip of clot model material. FIG. 5E illustrates removal of a clot model using an example aspiration catheter including a buffer flow opening as described herein. A rotational force is applied to the clot through the aspiration lumen based on the configuration of the buffer flow opening, causing the clot to be pushed against the proximal edge region of the aspiration opening, including rotating (and everting) the clot to allow for cutting of the strip of clot model material. FIG. 5F illustrates removal of a model blood clot using an example aspiration catheter including buffer flow apertures as described herein.A rotational force is applied to the clot through the aspiration lumen based on the configuration of the buffer flow opening, causing the clot to be forced against the proximal edge region of the aspiration opening, including rotating (and everting) the clot to allow for cutting of the strip of clot model material. FIG. 5G illustrates removal of a clot model using an example aspiration catheter including a buffer flow opening as described herein. A rotational force is applied to the clot through the aspiration lumen based on the configuration of the buffer flow opening, causing the clot to be forced against the proximal edge region of the aspiration opening, including rotating (and everting) the clot to allow for cutting of the strip of clot model material. [Figure 6]

[0080] FIG. 6A is a diagram showing an example of a distal end region of an aspiration catheter device, showing an example of a distal end region including a single buffer flow opening. FIG. 6B is a diagram showing an example of a distal end region of an aspiration catheter device, showing an example of ... [Figure 7]

[0081] 7A is a diagram showing an example of a distal end region of an aspiration catheter described herein that includes buffer flow openings of different sizes, numbers, and locations. FIG. 7B is a diagram showing an example of a distal end region of an aspiration catheter described herein that includes buffer flow openings of different sizes, numbers, and locations. FIG. 7C is a diagram showing an example of a distal end region of an aspiration catheter described herein that includes buffer flow openings of different sizes, numbers, and locations. FIG. 7D is a diagram showing an example of a distal end region of an aspiration catheter described herein that includes buffer flow openings of different sizes, numbers, and locations. FIG. 7E is a diagram showing an example of a distal end region of an aspiration catheter described herein that includes buffer flow openings of different sizes, numbers, and locations. [Figure 8]

[0082] FIG. 8A shows an example of a distal end region of an aspiration catheter that includes flow openings that are not properly configured to operate as buffer flow openings, where a single opening located proximal to the longitudinal center of the aspiration opening results in a failure to impart a rotational force to the clot material. FIG. 8B shows an example of a distal end region of an aspiration catheter that includes flow openings that are not properly configured to operate as buffer flow openings, where a single opening located proximal to the aspiration opening and on the same side as the aspiration opening results in a failure to impart a rotational force to the clot material. FIG. 8C shows an example of a distal end region of an aspiration catheter that includes flow openings that are not properly configured to operate as buffer flow openings, where two openings positioned approximately at the longitudinal center of the aspiration opening and radially offset by approximately 90 degrees from the lateral centerline of the aspiration opening failed approximately 50% of the time. [Figure 9]

[0083] FIG. 9A is a diagram showing an example of a distal end region including an aperture that is tested to determine the proper longitudinal position of the aperture, showing the time required to aspirate the tissue. FIG. 9B is a diagram showing an example of a distal end region including an aperture that is tested to determine the proper longitudinal position of the aperture, showing the time required to aspirate the tissue. FIG. 9C is a diagram showing an example of a distal end region including an aperture that is tested to determine the proper longitudinal position of the aperture, showing the time required to aspirate the tissue. FIG. 9D is a diagram showing an example of a distal end region including an aperture that is tested to determine the proper longitudinal position of the aperture, showing the time required to aspirate the tissue. FIG. 9E is a diagram showing an example of a distal end region including an aperture that is tested to determine the proper longitudinal position of the aperture, showing the time required to aspirate the tissue. [Figure 10]

[0084] 10A, 10B, and 10C are diagrams showing examples of different distal end regions including buffer flow openings with different sized openings (surface areas). [Figure 11]

[0085] 1 is a table showing different relative size openings of buffer flow openings compared to the size of the suction openings (eg, ratio of buffer flow openings aggregate area to suction area). [Figure 12]

[0086] 13 is a table showing the results of testing different relative size openings of buffer flow openings compared to the size of the suction openings from Table 11 on aspiration flow rates to capture clot material. [Figure 13]

[0087] 13 is a graph of the data shown in FIG. 12. [Figure 14]

[0088] FIG. 14A is a diagram showing examples of different distal end regions of a suction catheter having different numbers of buffer flow openings (all normalized to the same total opening area). FIG. 14B is a diagram showing examples of different distal end regions of a suction catheter having different numbers of buffer flow openings (all normalized to the same total opening area). FIG. 14C is a diagram showing examples of different distal end regions of a suction catheter having different numbers of buffer flow openings (all normalized to the same total opening area). FIG. 14D is a diagram showing examples of different distal end regions of a suction catheter having different numbers of buffer flow openings (all normalized to the same total opening area). [Figure 15]

[0089] FIG. 14A-14B is a graph showing the effect of different numbers of buffer flow openings on the time to aspirate a blood clot model using the distal end regions shown in FIGS. 14A-14B. [Figure 16]

[0090] FIG. is a diagram showing the distal end region of an example of a suction catheter including buffer flow openings and a shroud region for offsetting the buffer flow openings from the wall of the lumen and / or blood clot material within the lumen during use. [Figure 17]

[0091] FIG. 17 schematically shows an example of a suction catheter including a displacement protrusion extending from an outer surface of a distal end region configured to displace an outer opening of a buffer flow opening from a wall of a blood vessel. FIG. 17A is a graph showing the change in pressure over time using a catheter such as the catheter shown in FIG. 17. [Figure 18]

[0092] FIG. schematically shows an example of a suction catheter including a mechanical repositioner. [Figure 19]

[0093] FIG. 19A is a diagram showing an example of a suction catheter described herein including buffer flow openings acting on blood clot material. FIG. 19B is a diagram showing an example of a suction catheter described herein including buffer flow openings acting on blood clot material. FIG. 19C is a diagram showing an example of a suction catheter described herein including buffer flow openings acting on blood clot material. FIG. 19D is a diagram showing an example of a suction catheter described herein including buffer flow openings acting on blood clot material. [Figure 20]

[0094] FIG. 20A shows an example of a strip of clot collected as described herein using an aspiration catheter with a buffered flow opening.

[0095] FIG. 20B is a schematic diagram of the distal end region of an aspiration catheter similar to the one used to collect the strip of clot shown in FIG. 20A. [Figure 21AB]

[0096] 21A is a schematic diagram of a tip including a buffer flow opening having an outlet facing the longitudinal centerline of the suction opening (and at least one outlet distal to the longitudinal centerline) and configured to apply a buffer flow from a proximal fluid source (e.g., an external fluid source).

[0096] FIG. 21B is a schematic diagram of a tip including a buffer flow opening having an outlet facing the longitudinal centerline of the suction opening (and at least one outlet distal to the longitudinal centerline) and configured to apply a buffer flow from a proximal fluid source (e.g., an external fluid source). [Figure 21C]

[0097] FIG. 21C is a schematic diagram of an example of an apparatus using a buffer flow aperture configured as shown in FIGS. 21A and 21B. [Fig. 21D-G]

[0098]

[0098] Figure 21D is a top view of an example of a buffer flow device as described herein.

[0098] Figure 21E is a bottom view of an example of a buffer flow device as described herein.

[0099] FIG. 21F illustrates an example of a proximal end (eg, handle) region of a device such as the buffer flow aspiration catheter device of FIGS. 21D-21E.

[0100] FIG. 21G is a cross-sectional view through the proximal portion of the aspiration catheter of FIG. 21F (taken through line AA in FIG. 21F). [Fig. 21H]

[0101] FIG. 21D-21G is an illustrative side view of a distal region of an aspiration catheter similar to that shown in FIGS. 21D-21G in contact with clot material. [Figure 21I]

[0102] 21H is a schematic diagram illustrating the operation of the handle region of the aspiration catheter of FIG. 21H. [Figure 22]

[0103] 1A-1C are schematic diagrams illustrating a method of removing clot material using an aspiration catheter device described herein that includes a buffer flow aperture. [Figure 23A]

[0104] FIG. 1 is a cross-sectional view through the distal end region of an example aspiration catheter transverse to its longitudinal axis, showing the buffer flow region below the aspiration opening. [Figure 23B]

[0105] FIG. 1 is a side view of a distal end region of an example aspiration catheter including a buffer flow opening that maintains a buffer flow region below the aspiration opening. [Figure 24A]

[0106] FIG. 1 is a side view of the distal end region of an example aspiration catheter including buffer flow openings, illustrating the offset of the aspiration openings relative to the centerline of the inner lumen of the catheter shaft. [Fig. 24B-D]

[0107] 24B1 and 24B2 are side and end views of a suction catheter as described herein.

[0108] 24C1 and 24C2 are side and end views of a suction catheter as described herein.

[0109] 24D1 and 24D2 are side and end views of a suction catheter as described herein. [Diagram 25]

[0110] FIG. 1 shows a distal end region of an example aspiration catheter including a buffer flow opening, where the distal tip region includes an eddy current region (tip hold-up region) in the region of the aspiration lumen distal to the aspiration opening. [Figure 26]

[0111] FIG. 13 is a cross-sectional view through the distal end region of an example aspiration catheter across its long axis, including an area within the buffer flow region protected by an internal (e.g., navigation) lumen within the aspiration lumen that prevents occlusion by blood clot material. [Figure 27]

[0112] 27A illustrates an example of a suction catheter as described herein configured to apply external saline, e.g., in addition to (or in some instances instead of) buffer flow from the proximal end of the device through one or more buffer flow openings. FIG. 27B illustrates an example of a suction catheter as described herein configured to apply external saline, e.g., in addition to (or in some instances instead of) buffer flow from the proximal end of the device through one or more buffer flow openings. [Figure 28]

[0113] Figure 28A illustrates an example of an aspiration catheter described herein configured to apply external saline in addition to (or in some instances, instead of) buffer flow from the distal end of a second lumen (e.g., navigation lumen) through one or more buffer flow openings, Figure 28B illustrates an example of an aspiration catheter described herein configured to apply external saline in addition to (or in some instances, instead of) buffer flow from the distal end of a second lumen (e.g., navigation lumen) through one or more buffer flow openings, and Figure 28A is a schematic illustration of the catheter shown in Figure 28B with a portion of the distal end cut away to show internal details. [Figure 29]

[0114] 29 shows a schematic illustration of an example distal end of an aspiration catheter configured to apply external saline in addition to (or, in some examples, instead of) buffer flow through one or more buffer flow apertures. A portion of the distal region of the catheter in FIG. 29 is shown cut away to reveal internal details. [Diagram 30]

[0115] 30 is a schematic diagram of another example of a distal end of an aspiration catheter configured to apply external saline in addition to (or, in some examples, instead of) buffer flow through one or more buffer flow apertures. A portion of the distal region of the catheter in FIG. 30 is shown cut away to reveal internal details. [Diagram 31]

[0116] FIG. 13 shows another example of an aspiration catheter configured to apply an external fluid (in this example), which may be blood from a region of the vessel distal to the clot, into the aspiration tip of the aspiration catheter using an expandable lumen. [Diagram 32]

[0117] FIG. 1 shows a schematic diagram of an example of a device for blood collection and / or perfusion, for example during a clot capture procedure. [Diagram 33]

[0118] FIG. 33A illustrates an example of a method of operating a device for collection of blood and / or reperfusion of blood entering a patient, such as the device shown in FIG. 32. FIG. 33B illustrates an example of a method of operating a device for collection of blood and / or reperfusion of blood entering a patient, such as the device shown in FIG. 32. FIG. 33C illustrates an example of a method of operating a device for collection of blood and / or reperfusion of blood entering a patient, such as the device shown in FIG. 32. FIG. 33D illustrates an example of a method of operating a device for collection of blood and / or reperfusion of blood entering a patient, such as the device shown in FIG. 32. FIG. 33E illustrates an example of a method of operating a device for collection of blood and / or reperfusion of blood entering a patient, such as the device shown in FIG. 32. [Diagram 34]

[0119] FIG. 13 is a schematic diagram of an example of a device for blood collection and / or perfusion, e.g., during a clot capture procedure, that includes a partition valve. [Diagram 35]

[0120] 35A and 35B are diagrams illustrating the operation of an example of a partition valve (shown in this example as an umbrella valve). [Diagram 36]

[0121] FIG. 36A illustrates an example of a method of operating a device for collection of blood and / or reperfusion of blood entering a patient, such as the device shown in FIG. 34. FIG. 36B illustrates an example of a method of operating a device for collection of blood and / or reperfusion of blood entering a patient, such as the device shown in FIG. 34. FIG. 36C illustrates an example of a method of operating a device for collection of blood and / or reperfusion of blood entering a patient, such as the device shown in FIG. 34. FIG. 36D illustrates an example of a method of operating a device for collection of blood and / or reperfusion of blood entering a patient, such as the device shown in FIG. 34. FIG. 36E illustrates an example of a method of operating a device for collection of blood and / or reperfusion of blood entering a patient, such as the device shown in FIG. 34. [Figure 37]

[0122] 1A-1D are schematic diagrams illustrating examples of devices for blood collection and / or perfusion, for example, during clot capture surgery. [Figure 38]

[0123] 1A-1D are schematic diagrams illustrating examples of methods for reperfusing blood during a clot removal procedure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0072]

[0124] The aspiration methods and apparatus described herein may include an aspiration catheter as well as a reperfusion device, which may be used together (e.g., as part of the same system) or separately.

[0073]

[0125] In general, the aspiration catheters described herein (also referred to equivalently as aspiration catheters) are configured to remove clot material from a patient. These aspiration catheters may be configured to remove clots in longer strips, which may prevent or reduce the risk of releasing smaller clot fragments back into the vessel. Longer strips may allow for post-operative analysis, including more accurate determination of the amount of clot removed and the characteristics of the clot. The aspiration catheters described herein may be configured to prevent catheter blocking by clots, which may occur when the size of the clot material is larger than the aspiration opening into the aspiration catheter, as is often the case. This type of clot formation is often referred to as "lollipop formation." The aspiration catheters described herein may use one or more buffer flow openings to impart a rotational force to the clot at the aspiration opening; in some cases, this may rotate or flip the clot material relative to the aspiration opening, forcing the clot material to strike the proximal edge of the aspiration opening. The buffer flow openings may create an entrained flow of fluid (e.g., blood) within the aspiration lumen of the catheter, drawing the cut strips of clot material into the aspiration lumen. Additionally, these aspiration catheters may be configured to remove clots more rapidly and may remove less blood from the patient.

[0074]

[0126] In general, the apparatus described herein (e.g., devices and systems including aspiration catheters) may include a laterally positioned aspiration opening that may be on a tapered surface of the distal end region of the catheter. The tapered shape may aid the device in navigating the lumen of the vessel. The distal end region (sometimes referred to herein as the distal tip region or simply the distal tip) may be formed entirely of a soft material. In some examples, the catheter may include one or more lumens. At least one lumen may be configured as aspiration (or aspiration lumen) in communication with the aspiration opening. In some examples, the aspiration catheter may include a second lumen, which may be referred to as a guide lumen or diagnostic catheter lumen, that may extend distally through the aspiration opening. The guide lumen may be configured to allow for the passage of a guidewire, guide catheter, diagnostic catheter, or the like. The guide lumen may open into the aspiration lumen. In some instances, the guide lumen opens at least partially into the aspiration lumen such that when no additional elongate member (e.g., a guidewire, guide catheter, diagnostic catheter, etc.) is present within the guide lumen, fluid may pass from outside the catheter, through the distal end opening and into the aspiration lumen.

[0075]

[0127] Any of the devices described herein may include one or more buffer flow openings configured to prevent clogging and to push the clot material against the proximal edge of the suction opening. In some examples, the buffer flow openings may be configured to generate a rotational force on the clot material at the suction opening, which may prevent clogging of the clot material and / or help cut a strip from the clot material so that the clot material is entrained down the lumen. As described in detail herein, the buffer flow openings may be configured in this manner based on one or more of a longitudinal position relative to the suction opening, a radial position relative to the suction opening, a number of openings, and / or an aggregate size of the openings relative to the size of the suction opening.

[0076]

[0128] A common problem with many venous thrombectomy catheters that use suction to remove clots from the pulmonary artery is that the clot blocks the distal end of the catheter, resulting in a lollipop effect. The catheter must then be removed from the patient and unclogged during surgery before the device can remove the remainder of the clot within the patient. This tends to occur when the clot is larger than the aspiration lumen of the catheter through which the clot passes and is removed. If the catheter is not sharp enough to core the clot, the clot is pushed to the distal end of the catheter. When the distal aspiration opening of the catheter becomes clogged, the flow rate tends to zero and the dynamic interaction of the clot with the tip of the clot (coring) is reduced. However, in some cases, catheters (e.g., aspiration catheters) may be made sharp enough to allow for the core-out of the clot; however, this sharpness can result in other problems and can lead to vessel trauma or perforation. Aspiration catheters described herein including one or more buffer flow openings may provide sufficient clot aspiration and / or shearing while ensuring that the tip and clot orifice are atraumatic. Aspiration catheters described herein may include a distal end region of the catheter which, in conjunction with the configuration of one or more buffer flow openings, may bias clot material to a proximal edge region of the aspiration opening where shearing may occur without blocking the flow rate of the catheter.

[0077]

[0129] The distal tip region may be configured for use as an integrated dilator and atraumatic tip that allows the user to advance the aspiration catheter from the right femoral vein, across the heart and into the pulmonary artery. The distal tip region may allow the user to move the catheter and simultaneously aspirate if desired.

[0078]

[0130] FIG. 1 shows an example of an aspiration ("suction") catheter as described herein. In any of the devices described herein, the distal tip region 118 of the aspiration catheter 100 may be configured to be atraumatic and tapered in a distal to proximal direction, which may facilitate insertion and advancement through the vessels and across the heart. The distal end region 118 extends from the distal end of the elongated catheter body. The distal end region 118 of the aspiration (suction) catheter may have an aspiration opening 104 on the side. The aspiration catheter may include a distal opening 105 that enters the guide lumen. In some instances, the lumen and distal opening may be sufficient to allow a 4Fr catheter to be advanced and rotated through the lumen, allowing the 4Fr catheter to ride over a guidewire during surgery. In the example shown in FIG. 1, diagnostic catheter 106 is shown extending distally from the guide lumen and out of distal opening 105; guidewire 111 extends from the lumen of diagnostic catheter 106.

[0079]

[0131] The distal end region (e.g., "tip") 118 may be made from an elastomer (e.g., 55D TPU) that is stiff enough to resist collapse under full vacuum, yet soft enough to track through the heart without causing vascular injury. In some instances, the distal end region may be made from a more flexible material, and a stiffening member may be used to add hoop strength to the area of ​​the suction opening 104. This is shown in FIG. 2A, which shows an example of a distal end region 218 that includes a hoop strength support 212. This hoop strength support 212 could be a stainless steel stiffening member, such as a partial ring or a stiffer plastic overmolded section.

[0080]

[0132] In Figures 2A and 2B, the tip 218 has a suction opening 204 on its sloping (tapered) surface through which the clot can be aspirated. This opening is elongated along the long axis (longitudinal axis) of the catheter and is wider at the more proximal end than at the more distal end. The entire edge of the suction opening 204 or just the proximal edge 208 of the opening may be configured to have additional raised material around it to help resist collapse under vacuum. This raised area may be configured as a lip 220 (which may be reinforced by including additional material and / or may be reinforced by including material that is stronger and / or more rigid, which may be referred to as a reinforced lip). These design elements may allow the suction opening to create a shear quadrant (proximal edge 208) against which the clot can be sheared when the vacuum is turned on. This proximal edge area is highlighted in Figure 2B and may be where the majority of the clot shearing occurs. As will be described in more detail, the one or more buffer flow apertures as well as the tip shape may provide fluid dynamics about the tip that force clot material against this proximal edge region during aspiration.

[0081]

[0133] 2A and 2B, the distal end region 218 may include the distal opening 205 described above. The distal end region 218 may include one or more buffer flow openings 214.

[0082]

[0134] The suction opening may be generally shaped to generate a relatively high velocity flow across the proximal edge of the tip. During aspiration, a tip opening that is wider at the more proximal edge (the "proximal quadrant") and substantially wider than the distal quadrant may allow a higher velocity flow to occur across this proximal edge region of the opening. For example, FIG. 3A shows a top view, looking down at the suction opening 304, of an example tip described herein. In this example, the tip region includes a distal opening 316 that opens to both the suction lumen and the guide lumen. An array of buffer flow openings 307 is located radially opposite from the suction opening 304. The proximal edge 308 (or proximal quadrant) is shown.

[0083]

[0135] This shape of the suction opening, in combination with the location, shape, and size of the buffer flow opening, may increase the force on the clot at the proximal edge of the suction opening, as shown by the flow lines shown in FIG. 3B. The buffer flow opening may be positioned to help maintain a high flow rate within the device as the clot approaches the suction opening, keeping the clot biased toward the shear proximal edge of the suction opening. In this example, the small buffer flow opening is positioned on the opposite side of the tip to the orifice (e.g., radially offset from the longitudinal centerline of the suction opening), so that as the clot begins to occlude the suction opening and the flow rate begins to drop through the suction opening, the buffer flow opening may increase the flow rate and provide a rotational force on the clot, rotating and / or flipping the clot against the suction opening, helping to ensure that the clot material continues to move and hits the proximal edge and is cut. This may prevent the flow rate through the catheter from decreasing, and may prevent clogging of the catheter as long strips of clot are removed. The buffer flow openings create a "flow cushion" to ensure that the catheter does not clog and that there is continuous flow through and into the catheter. This is also shown in Figure 3C, which shows the clot material 355 being forced against the proximal edge 308 of the suction opening 307. The flow 380 from the buffer flow opening 307 may combine with the flow from the suction opening 304 to provide a rotational force on the clot material 355.

[0084]

[0136] For example, during aspiration, when the clot is not proximate to the aspiration opening, the majority of the flow may occur through the orifice and the buffer flow opening may provide a relatively small amount of flow entering the aspiration opening. As the clot material approaches and is drawn into the distal end region of the catheter, the flow through the buffer flow opening may begin to increase, creating a fluid buffer that pushes the clot against the proximal edge of the tip aspiration opening and will maintain a flow rate within the aspiration catheter such that a continuous flow rate moves within the lumen of the catheter, transporting the clot proximally towards the collection chamber.

[0085]

[0137] The buffer flow openings may be configured to be positioned some distance from the proximal edge of the suction opening (and in some instances at least one opening may be distal to the longitudinal centerline of the suction opening), and may be in multiple locations and have different shapes or locations. Examples of successful buffer flow opening locations and sizes are as follows: The buffer flow openings may collectively create a "flow pillow" that distributes flow over a larger area. As such, the buffer flow openings may have an optimal size, number, and location to maintain flow rate through the suction opening without adversely affecting clot engagement.

[0086]

[0138] For example, Figure 4A shows an example of a catheter 401 with a suction opening on the side of the distal end region that does not include a buffer flow opening. In Figure 4A, clot material 434 has lodged ("lollipopped") over the suction opening 404.

[0087]

[0139] 4B and 4C show an example of an aspiration catheter 400 that includes multiple buffer flow openings as described herein. These buffer flow openings allow for continuous flow as the clot approaches the tip and impart a rotational force 436 to the clot 434, creating a buffer of flow to ensure that the clot does not lollipop at the end of the aspiration catheter 400. As shown, as the clot material is pushed by the aspiration flow from both the aspiration and buffer flow openings, the clot material 434 rotates against the proximal edge of the aspiration opening, shearing the clot material and cutting a strip from the clot material that is then entrained by the flow into the aspiration lumen without clogging.

[0088]

[0140] 5A-5G show another example of a model clot material 534 that is rotated and everted as it is forced against the proximal edge of the suction opening when suction is applied through the suction lumen of an aspiration catheter 500 having multiple buffer flow openings. FIGS. 5A-5G show the movement of the clot material as it rotates against the proximal edge of the suction opening. In FIG. 5A, when the suction opening is close enough to the clot material such that the clot material is drawn into the suction opening, the flow of fluid (e.g., blood) from the buffer flow opening into the catheter 500 directs the clot material proximally against the proximal edge of the suction opening, so that the clot material moves proximally relative to the distal tip region, as shown in FIG. 5B. The flow from the suction lumen and buffer flow openings everts the clot material 534 against the suction opening, as shown in FIGS. 5C and 5D. As the clot material continues to be forced against the proximal edge of the suction opening as it rotates (e.g., is everted) relative to the suction opening, one (or more) strips of material are cut and pulled into the suction lumen of the catheter 500 until all of the clot material is removed, as shown in Figures 5E-5G.

[0089]

[0141] As noted above, configuration of one or more parameters of the openings may enable the openings to function as described in Figures 4B-4C and 5A-5G such that the openings act as buffer flow openings. These parameters may be optimized so that the buffer flow openings apply an appropriate rotational force to the clot material adjacent the suction opening and so that removal of the clot material is sufficiently rapid (e.g., so that the time to aspirate the clot is below a target level that may minimize blood loss and surgery time). These parameters of the buffer flow openings may include the longitudinal (e.g., axial) position of the one or more buffer flow openings relative to the suction opening, the radial position of the buffer flow openings relative to the suction opening, the aggregate size of all of the openings of the buffer flow openings relative to the size of the suction opening, and the number of openings. For example, one or more buffer flow openings may be generally positioned such that the buffer flow opening is distal to a proximal edge region of the suction opening, more specifically such that at least one of the buffer flow openings should be distal to the longitudinal centerline of the suction opening, and / or such that the average longitudinal position of the buffer flow openings is at or distal to the longitudinal centerline of the suction opening. Additionally, the buffer flow openings may be radially positioned (relative to the suction opening) such that they are radially offset from the longitudinal centerline of the suction opening by an angle greater than 90 degrees (e.g., greater than 100 degrees, greater than 110 degrees, greater than 120 degrees, between 90 degrees and 180 degrees, between 100 degrees and 180 degrees, etc.). The angle of the buffer flow opening relative to the longitudinal centerline of the suction opening may be measured from the center of the buffer flow opening.

[0090]

[0142] Generally, the relative size of the suction opening to the sum of the sizes of the buffer flow openings may be between about 10:1 and 18:1 (e.g., between about 11:10 and 17:1, between about 10:1 and 16:1, between about 12:1 and 16:1, between about 12:1 and 14:1, etc.). Generally, buffer flow openings that are too large will not work. Generally, the vacuum applied may be greater than about 510 mmHg (e.g., the difference between the pressure in the vessel and the pressure in the aspiration lumen may be greater than 250 mmHg).

[0091]

[0143] 6A-6E show examples of distal end regions (tips) that include buffer flow openings. FIG. 6A shows a first example of a tip with a single buffer flow opening 614 positioned distal to the centerline 644 of the suction opening 604. In FIG. 6A, the buffer flow opening is blocked by a diagnostic catheter 606 extending through the guide lumen. As such, the buffer flow opening may be closed or opened by inserting or removing the diagnostic catheter. The buffer flow opening may pass through the guide lumen to allow fluid from outside the tip to pass into the aspiration lumen when the diagnostic catheter does not cover the buffer flow opening. In some examples, the buffer flow opening is radially offset from the guide channel (and any diagnostic catheter that may be present), as shown in FIGS. 6B and 6C. In FIG. 6B, two buffer flow openings 614, 614′ are positioned distal to the centerline 644 of the suction opening 604. In FIG. 6C, the buffer flow openings 614 , 614 ′ are positioned distal to the centerline 644 of the suction opening 604 .

[0092]

[0144] In any of these aspiration catheters described herein, the buffer flow opening may be a distal opening 616, as shown in Figure 6D. In this example, the only buffer flow opening is the distal end opening; in some examples, a side buffer flow opening may be included opposite from the aspiration opening.

[0093]

[0145] FIG. 6E shows a perspective view of an example tip having four buffer flow openings, all positioned at or distal to the centerline of the suction opening and all radially offset by approximately 160 degrees from the longitudinal centerline of the suction opening, so that the buffer flow openings are not blocked by the presence of the diagnostic catheter 606, as shown.

[0094]

[0146] The buffer flow openings in FIGS. 6A-6E are all circular openings. In some instances, the buffer flow openings may be other shapes, including oval, rectangular, triangular, etc. Additionally, the buffer flow openings described herein are primarily formed directly through the wall of the tip (and / or any guide lumen). In some instances, the buffer flow openings may have outputs that open into the aspiration lumen at the locations noted above (e.g., typically distal to the proximal opening, and particularly at or distal to the longitudinal centerline of the aspiration opening), while the inputs entering the buffer flow openings may be located more proximally, including extending (e.g., through a buffer flow channel) to the proximal end of the device or to a more proximal region of the catheter. A buffer flow channel may be preferred, for example, when flow from the buffer flow opening is actively applied, rather than simply applied by applied suction from the aspiration lumen.

[0095]

[0147] 7A-7E show examples of buffer flow openings having different locations, positions, numbers, and shapes. In general, the parameters of the buffer flow openings may be selected to minimize blood loss and minimize the time required to remove a clot from the vessel. FIG. 7A shows an example of a tip having two buffer flow openings 714 located approximately at the midline of the suction opening (similar to FIG. 6C), where the openings are each about 1 mm in diameter at the tip. FIG. 7B shows an example where the buffer flow openings 714 are elongated slots with dimensions 0.7 mm by 8 mm. FIG. 7C shows an example of an array of 9 (3×3) buffer flow openings 714 positioned distal to the midline of the suction opening. Each buffer flow opening has a diameter of 0.7 mm. FIG. 7D shows an example of a tip having an array of 20 (4×5) buffer flow openings 714, each about 0.5 mm in diameter. Finally, Figure 7E shows an example of a tip similar to Figure 6B with two buffer flow openings 714, each approximately 1 mm in diameter, positioned distal to the midline of the suction opening. The tips shown in Figures 7A-7E were investigated, as described below, to determine the characteristics of the buffer flow openings that would optimally remove clot material with minimal blood loss.

[0096]

[0148] 8A-8C show examples of tips with apertures 817 that did not operate as buffer flow apertures to generate the rotational force and buffer flow described herein. In FIG. 8A, the tip included a very large aperture 817 and was unable to induce a rotational force or buffer flow. Similarly, FIG. 8B shows a tip with two smaller apertures 817 positioned proximal to the suction aperture (in FIG. 8B, the apertures were similarly positioned in the same radial location as the suction aperture, and similar results were seen for apertures positioned radially offset from the suction aperture), and the two smaller apertures 817 were similarly unable to generate a rotational force and buffer flow. Both tips in FIG. 8A-8B were unable to rapidly remove the clot and prevent it from lollipopping. The tip shown in FIG. 8C provided a moderate success rate, clogging (or lollipopping) approximately 50% of the time. In this example, the apertures 817 are positioned at the centerline (e.g., longitudinal centerline) of the suction aperture and radially offset by 90 degrees from the long axis (longitudinal axis) of the suction aperture.

[0097]

[0149] In general, the buffer flow opening should be positioned distal to the suction opening. As shown in Figures 9A-9E, there was a dramatic increase in the effectiveness of the buffer flow opening to prevent clogging and remove strips of clot material when the buffer flow opening was positioned at or distal to the midline (e.g., center 944) of the suction opening. The tips shown in Figures 9A-9E were investigated using model clot material under identical conditions to estimate the time required to remove the clot material (time to aspirate) as shown. In this example, for the tip shown, the results showed that overall, the closer the buffer flow opening was to the center of the opening 944, the faster the clot material was removed. Additionally, the more distal example was able to generate a greater rotational force on the clot material, preventing clogging and allowing removal of longer strips of clot material.

[0098]

[0150] Figures 10A-10C show tips with different relative sizes for the buffer flow aperture (versus the suction aperture). In Figure 10A, the aperture is a single hole (similar to the hole shown in Figure 8A) with a diameter of 4 mm, and the area of ​​the hole is approximately 12.57 mm.2 In each of Figures 10A to 10C, the suction opening is approximately 35.63 mm 2 The ratio of suction openings to additional openings (e.g., buffer flow openings) in Figure 10A is approximately 2.83:1 (so the area of ​​the additional openings is approximately 35.3% of the area of ​​the suction openings). In Figure 10B, an array of 9 openings, each 0.5 mm in diameter, has an area of ​​approximately 1.76 mm 2 Arrays were tested having a total open area for the additional openings (e.g., buffer flow openings) of approximately 1.57 mm. Thus, the ratio of suction openings to additional openings (e.g., buffer flow openings) in FIG. 10B is approximately 20:1, and the area of ​​the additional opening(s) is approximately 4.9% of the area of ​​the suction openings. In FIG. 10C, two openings, each 1 mm in diameter, are approximately 1.57 mm. 2 Two openings were tested, each having an open area for the additional opening (e.g., buffer flow opening) of 100 mm. Thus, the ratio of suction openings to additional openings (e.g., buffer flow openings) in FIG. 10C is approximately 23:1, and the area of ​​the additional opening(s) is approximately 4.4% of the area of ​​the suction opening. While the tip shown in FIG. 10A did not work, the openings in the tips shown in FIGS. 10B and 10C did indeed work as buffer flow openings.

[0099]

[0151] The effect of the size of the buffer flow aperture(s) on the tip's ability to provide rotational force, prevent clogging, and rapidly remove strips of clot material was investigated for a variety of different buffer flow aperture sizes. The table in FIG. 11 shows examples of tips with multiple area ratios of buffer flow aperture to suction aperture open area. In FIG. 11, ratios of suction aperture size to buffer flow aperture size between 8 and 22 are listed, with corresponding hole diameters and areas. These tips were investigated in multiple trials, and the time to remove the clot (without clogging) was measured as shown in FIGS. 12 and 13. FIG. 13 graphically illustrates the results shown in the table in FIG. 12. In these trials, a model clot material (e.g., 10 cc of Flarp) was used within a vessel diameter of 22 mm. A vacuum of 740 mmHg was applied, and clot capture was recorded through video and analyzed frame by frame.

[0100]

[0152] Considering only the time to aspirate the entire clot, the ratio of suction opening area to buffer flow opening area (total) exhibits an optimal range of between about 10:1 and 18:1 (e.g., between 11:1 and 17:1, between 10:1 and 16:1, between 12:1 and 15:1, between 12:1 and 14:1, etc.).

[0101]

[0153] Similar experiments were performed to determine the optimal number of holes to be used. In this set of experiments, the ratio of suction opening area to buffer flow opening area was maintained at 12:1 with the number of holes varying between 2 and 8, and the holes were distributed symmetrically around the centerline 1444 of the suction openings as shown in Figures 14A-14D. The results are shown graphically in Figure 15, which shows that the time to aspirate an equivalent clot was roughly the same for numbers of buffer flow openings between 2 and 4. From 4 onwards, as additional pairs of holes were added, the time to aspirate increased slightly. The number of holes may be greater than 8. In some instances, a number of holes between 1 and 26 (e.g., between 1 and 20, between 2 and 20, etc.) may be used.

[0102]

[0154] Any of the devices described herein may be configured to prevent clot material and / or vessel wall material from occluding the buffer flow opening. For example, any of these devices may include an extension (e.g., a shroud) extending from an outer surface of the elongate body to prevent the buffer flow opening from being blocked. In some cases, the extension is a protrusion that extends opposite the suction opening, the protrusion being some distance away from the buffer flow opening to prevent clot material from entering the buffer flow opening and / or to prevent the lumen wall from covering (and blocking) the buffer flow opening.

[0103]

[0155] For example, Figure 16 shows an example of a protrusion or shroud 1662 that forms a distally facing wall around the buffer flow opening 1614. In this example, the protrusion is a T-shaped protrusion that extends out of the outer surface of the tip, which may allow space from the vessel (lumen) wall and may block clot material from growing and covering the opening.

[0104]

[0156] In some examples, the buffer flow opening may include a distal opening, for example a distal tip opening through which a diagnostic catheter may exit. Other examples may include the use of a membrane / mesh / filter material that covers the buffer flow opening.

[0105]

[0157] Thus, in any of these examples, one or more ridges in the tip may create an area under the clot that flow may pass through to keep the clot moving. In some examples, the ridges may be the outer surface of the guide lumen (e.g., the tube through which the navigation / diagnostic catheter passes). Alternatively, as shown in FIG. 16, the protrusions may be formed by one or more features incorporated into the tip itself.

[0106]

[0158] Thus, the holes (buffer flow openings) may be made non-clogging by including a raised barrier on the outside of the tip, which may create a mechanical stop that keeps blood clots from clogging the holes. These clot barriers can be passive (e.g., rigid) or active (e.g., expandable, such as a balloon or spring-based member that may be controllably extended and / or retracted from the proximal end of the device).

[0107]

[0159] Any of these aspiration catheters may include a mechanical method for generating continuous flow instead of or in addition to the buffered flow openings described herein. For example, Fig. 17 shows an example of a catheter 1700 that includes an additional pressure source (e.g., bellows 1717) at the proximal end of the catheter that may rapidly raise and lower the vacuum level in the shaft to generate turbulent flow, for example, by pumping the bellows and applying a force (F) to alter the pressure in the aspiration lumen (shown by inset graph 17A) to ensure that the catheter does not become clogged by a clot 1734 lodged at the end of the catheter.

[0108]

[0160] Alternatively or additionally, FIG. 18 shows another example of a catheter 1800 having a mechanical linkage system (e.g., mechanical repositioner 1881) with a distal member that may mechanically reposition the clot 1834 (rather than simply by flow) to prevent blocking the suction opening and ensure continuous flow.

[0109]

[0161] In practice, the devices described herein including the buffer flow openings configured as described above may be used to remove blood clots within the body. For example, Figures 19A-19D show examples of aspiration catheters including a distal tip with multiple (e.g., four) buffer flow openings positioned at or distal to the midline of the suction openings as shown above. Clot material is positioned within a vessel to occlude the vessel. The distal end of the aspiration catheter is shown initially positioned near the clot material as shown in Figure 19A. Activating suction draws the clot material into the suction openings of the aspiration catheter, pulling the clot proximally against the proximal edge of the suction opening and cutting a long strip from the material as shown in Figure 19B. The buffer flow openings deliver a flow that imparts a rotational force to the clot material, causing it to turn over (in Figure 19C) and continue to push against the proximal edge of the suction opening (in Figure 19D) until the clot material is removed. In smaller diameter vessels where there was no space for the clot to evert or roll along the axis between distal and proximal, a combination of rotational forces from the flow through the buffer flow opening and suction from the suction opening moved the clot in a manner similar to a typewriter carriage; it was first pulled proximally, forced against the proximal edge of the suction opening (to cut), then pulled back distally and again pulled proximally to allow further cutting. In this example, the clot was approximately 10 g (75 cc) and the collateral blood flow was about 25 cc / sec.

[0110]

[0162] In an aspiration catheter described herein having a tip (distal end region) similar to the tips described above, such as the tip shown in FIG. 20B, which includes a tapered surface with aspiration openings 2104 entering the aspiration lumen and between two and four buffer flow openings 2114, clot material was removed in long strips by pushing the clot material against the proximal edge 2108. FIG. 20A shows an example of a strip of clot material removed using a tip similar to the tip shown in FIG. 20B. The clot material 2034 was removed in a long strip, although not as fragmented.

[0111]

[0163] Any of the devices and methods described herein may include a buffer flow opening, as indicated above, which is an aperture where the inlet to the aperture and the outlet to the aperture are both within the tip region of the device (and in some instances the inlet may be directly opposite the outlet of the buffer flow opening), or a buffer flow opening, rather than an aperture, where the outlet of the buffer flow opening is separated from the inlet of the buffer flow opening by a longitudinal distance.

[0112]

[0164] For example, Figures 21A-21B show a tip for a device described herein, where the buffer flow apertures have outlets positioned as described herein, and the buffer flow apertures (outlets) face the suction apertures such that at least one of the buffer flow aperture outlets 2184 extends distally beyond the centerline of the suction aperture. The inlets may open to a lumen 2188 that may be connected to a fluid source, as shown in Figure 21C, to provide buffer flow. In Figure 21C, external buffer flow fluid 2189 is provided through the inlets to the buffer flow aperture outlets. The device may otherwise be the same as the devices described herein. Flow through the buffer flow aperture outlets may be coordinated with application of suction (e.g., the buffer flow aperture outlets may be on at the same time, or buffer flow may be applied after the start of suction).

[0113]

[0165] 21D-21I show another aspiration catheter described herein that provides external fluid to an area near the buffer flow opening on the aspiration tip so that fluid can be drawn into the buffer flow opening and aspirated back through the aspiration lumen of the aspiration catheter, resulting in lifting of the clot upward toward the proximal edge of the aspiration opening as the clot passes through the opening. Injection of external fluid can be useful in areas within the body that have restricted fluid in a vessel, such as a peripheral vein, where inflow has been reduced by a proximal clot. FIGS. 21D and 21E show top and bottom views of the distal end of the catheter with aspiration opening 2104 positioned on a tapered surface of the distal end of the aspiration catheter. Four buffer flow openings 2114 are positioned on opposing surfaces of the catheter from the aspiration opening around the longitudinal centerline of the aspiration opening 2104. A navigation lumen 2115 is positioned between the buffer flow openings 2114 and extends parallel to the longitudinal axis of the aspiration lumen. The navigation lumen 2115 is a reinforced flexible lumen affixed to the inner wall of the aspiration lumen 2116 of the aspiration catheter in this embodiment. The navigation lumen 2115 is configured to accommodate a navigation catheter that fits a 0.035'' guidewire. The positioning of the navigation lumen 2115 aids in tracking of the aspiration catheter and serves as a shield to reduce the chance of blood clots entering the aspiration opening 2104 and blocking the buffer flow opening 2114. The infusion lumen 2115 is positioned next to the navigation lumen 2115 in FIGS. 21D-21E. The infusion lumen 2118 may be affixed to the inner wall of the aspiration lumen 2116. It should be understood that this lumen could also be attached to the outer wall of the catheter body. The infusion lumen 2118 could also be constructed of flexible lay-flat tubing such that when not in use the lumen is relatively flat against the wall and has minimal impact on the profile or area within the aspiration lumen 2116. 21D-21E, infusion lumen 2115 is constructed of a flexible, reinforced polymer tubing. The distal end of infusion lumen 2118 is positioned just proximal to the proximal edge 2108 of the suction opening 2104.The distal ends of the infusion lumens are plugged and at least one infusion distal opening 2119 opens through the sidewalls of the infusion lumen 2118 and the aspiration lumen 2116 such that the infusion lumens are in fluid communication with the vessel. FIG. 21F shows the proximal handle of the aspiration catheter. Within the handle, the aspiration lumen 2116 leads to an aspiration port 2116' and the infusion lumen 2118 leads to an infusion port 2118'. The infusion lumen port 2118' may be configured to accommodate a standard syringe lure lock. Positioned between the aspiration port 2116' and the infusion port 2118' is the navigation port 2115'. FIG. 21G shows a cross-sectional view of the aspiration lumen of the aspiration catheter, showing how the infusion lumen 2118 and the navigation lumen 2115 are positioned within the aspiration lumen 2116. Figures 21H and 21I show how this embodiment of the invention is connected and how an external fluid is injected into the vessel proximal to the buffer flow opening 2114. An external fluid chamber 2120 is connected to the injection port 2118'. In some embodiments, this chamber is positively pressurized. In other embodiments, the chamber is passive and when opened, fluid is drawn from the chamber by negative pressure created by vacuum pressure applied to the aspiration lumen 2116. The arrows shown in Figures 21H and 21I indicate the flow of external fluid.

[0114]

[0166] FIG. 22 illustrates one example of a method for removing clot material described herein using a tip including one or more buffer flow apertures. In FIG. 22, the method illustrated may include initially positioning 2201 the tip of an aspiration catheter near the clot material. A navigation catheter (e.g., a diagnostic catheter and / or guidewire) may be used to position a distal end region of the catheter proximal to the clot material within the lumen of the vessel such that the aspiration apertures are facing or near the clot material (which may point outward from the nearest wall of the vessel). The catheter may be rotated eccentrically about the diagnostic catheter and / or guidewire to help orient and position it relative to the clot material and vessel wall.

[0115]

[0167] Suction may be applied through the suction opening to draw the clot material into the suction opening; simultaneously, flow through one or more buffer flow openings may apply a rotation (e.g., a rotational force) to the clot material at the suction opening, forcing the clot material against the proximal edge of the suction opening 2203. Suction (aspiration) may continue while the clot material is cut into one or more strips against the proximal edge of the suction opening, so that the clot material is rotated and forced by the combination of flow from the suction opening and buffer flow opening 2205. This process may continue to remove long strands of material 2207, until the clot material is removed. The catheter may be repositioned during or after this process. Suction may be applied continuously or may be stopped periodically to remove the clot material from the collection chamber, as described in more detail below. buffer flow area

[0116]

[0168] In any of the examples described herein, the action of the aspiration catheter to remove clot material, particularly large clots, by rolling and detaching the clot (as opposed to fragmenting the clot) may benefit from maintaining a buffer flow region in the portion of the aspiration tip facing away from the aspiration opening. This buffer flow region may be established by the buffer fluid flow described above and / or as shown in the examples below. Figures 23A and 23B show a buffer flow region 2324 that may aid in the aspiration of large clots, for example, by rolling the clot material against the proximal edge of the aspiration opening to compress the clot and / or "unpeel" the clot so that it can be delivered to the aspiration lumen without clogging or lollipop formation. In FIG. 23A , a buffer flow region 2324 (shown as the area within the dashed outline) may be formed by buffer flow openings 2314, 2314′, 2314″, along the bottom of the suction lumen (suction lumen) 2316 facing away from the suction opening 2304. Fluid from the vessel (e.g., blood vessel) may flow in through these buffer flow openings 2304, 2306, 2308 upon application of suction through the suction lumen from the proximal end. The inflow may be deflected to some extent by the navigation lumen 2312 passing through the suction lumen 2316. In FIG. 23A , the catheter may include a contrast lumen 2312, which may terminate proximal to the suction opening 2304.

[0117]

[0169] FIG. 23B shows a side view of the distal tip region of the aspiration catheter of FIG. 23A. A buffer flow region 2324 is shown in the dashed area opposite from the aspiration opening 2304 (in the "lower" half of the aspiration lumen opposite from the aspiration opening). As will be described, this buffer flow region may be formed by fluid inflow through distally positioned buffer flow openings 2314, 2314'. In the example shown in FIG. 23B, the distal tip region includes four buffer flow openings (two on either side of the longitudinal centerline) on either side of an enclosed aspiration lumen 2312 that extends through the length of the device at the "lower" of the aspiration lumen. An example of a buffer flow 2364 is shown in FIG. 23B. In this example, the distal end of the aspiration lumen at the distal tip is enclosed, forming a vortex chamber 2322. The vortex chamber may be equivalently referred to herein as a hold-up region.

[0118]

[0170] In any of the devices and methods described herein, the location and size of the buffer flow openings may help establish an interference flow region configured to roll the clot material against the proximal end of the suction opening, preventing fragmentation of the clot material and enhancing capture. In general, these methods and devices may compress the clot material and / or roll it against the proximal edge of the suction opening without significantly wearing or breaking the clot material and without clogging it. As such, this technique for extracting and elongating the clot may minimize the potential for embolism. Instead, these methods and devices cut long strips from the clot material and / or reshape the clot material to take long strips, as discussed above, without significantly fragmenting the clot material.

[0119]

[0171] In Figures 23A-23B, the buffer flow region may result from the relative placement of the buffer flow openings and the suction openings. In any of these methods and devices, it may be beneficial for the ratio of buffer flow openings (total buffer flow openings) to suction openings to be between about 5% and about 10% (e.g., between about 6% and about 9%, between about 7% and about 8%, etc.). The ratio of buffer flow openings to suction lumen cross-section may be, for example, between about 5% and about 15% (e.g., between about 8% and about 13%, between about 10% and about 12%, etc.). Each individual buffer flow opening may be about 1-3% (e.g., about 2%) of the size of the cross-section of the suction lumen. As discussed and illustrated above, offset locations of the buffer flow openings relative to the suction openings may be particularly beneficial.

[0120]

[0172] In any of the devices described herein, the location of the suction lumen relative to the long axis of the catheter (particularly relative to the suction lumen) may significantly enhance the buffered flow effects described herein. For example, any of these devices may include a suction orifice 2404 that may be positioned entirely on the tapered side of the catheter, as shown in FIG. 24A, so that the distal-most edge of the suction opening does not intersect the longitudinal centerline 2450 of the suction lumen. FIG. 24A illustrates the positioning of the orifice centerline 2452, which is a line that passes through the longitudinal center of the suction orifice 2404 and extends parallel to the longitudinal axis of the suction lumen centerline 2450. In some instances, the distal-most edge of the suction opening is on the tapered surface of the suction lumen, but the suction opening does not extend further than about half (e.g., between 40% and 60%) of the transverse diameter of the suction lumen. Offsetting the suction orifice may bias clot entrainment toward the face of the shaft (aspiration catheter) opposite the buffer flow opening. The buffer flow region 2424 may extend from a more distal region toward a more proximal direction, with the flow direction at an angle (e.g., between about 90 and 160 degrees, between about 100 and 150 degrees, etc., relative to the direction of the clot entering the suction opening). This may allow the buffer flow openings 2414, 2414' to increase their flow rate when the suction orifice begins to become clogged with clots, helping to prevent clogging and providing a rotational force on the clot to rotate it against the proximal edge of the suction opening. The distal edge of the suction opening may be at or just above the midline of the suction lumen 2450. This configuration may prevent clogging or lollipop formation of clot material.

[0121]

[0173] 24B1-24B2, 24C1-24C2, and 24D1-24D2 show examples of devices in which the suction orifice extends on the tapered surface of the suction catheter such that the diameter of the suction lumen measured at the distal edge of the suction opening 2404 extends at least 40% (e.g., 45%, 50%, 55%, 60%, etc.) of the diameter of the suction lumen measured at the proximal edge of the suction opening. FIG. 24B1 shows a side view of a device having a suction opening 2404 that extends at approximately 40% of the diameter of the suction lumen; the diameter of the suction lumen measured at the distal edge of the suction opening 2404 extends at least 60% of the diameter of the suction lumen measured at the proximal edge of the suction opening. In FIG. 24B1, the longitudinal centerline 2450 is shown as a dashed line, while the line 2455 extending from the distal edge of the suction opening is shown as a solid line. FIG. 24B1 also shows the distance 2444 between the centerline and the distal edge, and the radial distance 2446 from the proximal edge of the suction to the distal edge of the suction opening is approximately 40% of the diameter of the suction lumen. FIG. 24B2 shows a distal end view of the device of FIG. 24B1, showing the suction opening 2404 and how deep the suction opening extends radially into the suction lumen. The suction opening extends approximately 40% of the diameter of the suction lumen (e.g., from the top edge of the suction lumen). FIG. 24C1 is a side view of another example of a device with a suction opening 2404' that extends approximately 50% of the diameter of the suction lumen (across the long axis of the suction lumen); the diameter of the suction lumen measured at the distal edge of the suction opening 2404' extends 50% of the diameter of the suction lumen measured at the proximal edge of the suction opening. In FIG. 24C1, the longitudinal centerline 2450 of the suction lumen is shown in dashed lines, which coincide with a line 2444' (shown in solid lines) extending from the most distal edge of the suction opening. FIG. 24C1 also shows the distance 2455' between the centerline and the distal edge, and the radial distance 2446' from the proximal edge of the suction to the distal edge of the suction opening is approximately 50% of the diameter of the suction lumen. FIG. 24C2 shows a distal end view of the device of FIG. 24C1, showing the suction opening 2404' and how deep the suction opening extends radially into the suction lumen. In this example, the suction opening extends (e.g., from the top edge of the suction lumen) approximately 50% of the diameter of the suction lumen.FIG. 24D1 is a side view of another example of a device having a suction opening 2404'' that extends approximately 60% of the diameter of the suction lumen (across the long axis of the suction lumen); the diameter of the suction lumen measured at the distal edge of the suction opening 2404'' extends 40% of the diameter of the suction lumen measured at the proximal edge of the suction opening. In FIG. 24D1, the longitudinal centerline 2450 of the suction lumen is shown in dashed lines and is spaced apart from a line 2444'' (shown in solid lines) that extends from the distal edge of the suction opening. FIG. 24D1 also shows the distance 2455'' between the centerline and the distal edge and the radial distance 2446'' from the proximal edge of the suction opening to the distal edge of the suction opening, which is approximately 60% of the diameter of the suction lumen. FIG. 24D2 shows a distal end view of the device of FIG. 24D1, showing suction opening 2404″ and how deep radially the suction opening extends into the suction lumen. In this example, the suction opening extends approximately 60% of the diameter of the suction lumen (e.g., from the top edge of the suction lumen).

[0122]

[0174] In fact, the aspiration catheters described herein may work surprisingly well to form a buffer flow region facing away from the aspiration opening, as described and demonstrated above, for example, when the diameter of the aspiration lumen measured at the distal edge of the aspiration opening extends 40% or more (e.g., 45% or more, 50% or more, 55% or more, 60% or more, etc.) of the diameter of the aspiration lumen measured at the proximal edge of the aspiration opening. This configuration of the aspiration opening and aspiration lumen may leave a region of the diameter of the aspiration lumen (facing away from the aspiration opening) that is spaced apart from the flow entering the aspiration lumen through the larger aspiration opening; this spaced apart region may form the buffer flow region described above in Figures 23A-23B. The flow in this region, which may be the result of flow entering the aspiration lumen through the buffer flow opening, may provide a rotational force on the clot material within the aspiration opening, driving the rotation and cutting a strip from the clot material, which may be aspirated as described herein.

[0123]

[0175] In any of these examples, the device may be configured such that the distal tip region 2527 of the catheter connected to the aspiration lumen (suction lumen) is closed to prevent fluid (or more likely, clot material) from entering the aspiration lumen and / or occluding the tip region. This may create a tip hold-up region 2522, as shown in FIG. 25, which may be beneficial. In FIG. 25, the tip hold-up region 2522 is a dead end with a hold-up volume. This volume may be filled with fluid (e.g., blood) and may redirect flow from the distal end toward the proximal end as part of a buffer flow region. For example, in FIG. 25, the distal tip region of the aspiration catheter is similar to the distal tip region shown in FIGS. 23B and 24, and includes a suction opening 2504 and four offset buffer flow openings 2514, 2514' (two on either side of the guide channel in the aspiration lumen). In this example, the distal tip region 2527 is the distal end (acting as a "dead end") distal to the suction opening 2504 and provides a flow barrier, preventing flow out of the distal end, creating tip eddy currents to bias clots to the side of the shaft where the proximal edge of the suction opening is. This eddy current region (tip hold up region) also acts to block flow from the buffer flow openings 2514, 2514'. This closed distal end region may be referred to as a shield region at the distal end of the device.

[0124]

[0176] In any of these examples, the buffer flow openings may be protected or shielded by one or more structures within the aspiration lumen. Thus, the buffer flow openings may be configured such that flow entering the aspiration lumen forms a buffer flow region. For example, as shown in FIGS. 23A-23B, 24, and 25, the buffer flow openings are adjacent to, and partially shielded by, the navigation lumen and, in some cases, an additional contrast lumen. For example, FIG. 26 shows an example of a cross section through the distal end region (tip region) of an aspiration catheter, as described herein, taken through a region intersecting the aspiration opening 2604. In FIG. 26, the cross section shows a pair of buffer flow openings 2614, 2614' adjacent to (e.g., adjacent to both sides of) the navigation lumen 2612 that extends proximally to distally on one side of the aspiration lumen of the catheter. This may protect or shield the buffer flow opening 2614 adjacent to the navigation catheter lumen 2624'. 26, the contrast lumen 2612 may enter this region as well, shielding the buffer flow opening, so that the buffer flow opening is protected from being clogged or blocked by clot material that is drawn into the aspiration lumen. Flow entering the buffer flow opening may be redirected by other structures within the navigation lumen and / or contrast lumen or aspiration lumen 2616 to help create and maintain the buffer flow region 2624 from the fluid flows 2604, 2606, 2608 entering the buffer flow opening.

[0125]

[0177] Generally, the buffer flow openings may provide a low pressure, relatively high flow rate opening into the aspiration lumen. These low pressure, high flow rate buffer flow openings may shock and redirect the clot material to the aspiration openings and aspiration lumen as described herein without disruption or fragmentation of the clot material. Generally, the pressure exerted by the buffer flow openings is derived from (and proportional to) the suction applied through the aspiration lumen. The buffer flow openings may be of any suitable size (as described above) and may operate to maintain a relatively low pressure.

[0126]

[0178] The aspiration lumen may be of any suitable diameter (e.g., about 10F or greater, 12F or greater, 14F or greater, 16F or greater, between 6F and 30F, between 8F and 28F, between 12F and 28F, etc.). In some cases, the aspiration device may be relatively narrow and include an aspiration lumen but not a separate navigation lumen (e.g., for a navigation catheter, navigation shaft, guidewire, etc.) and / or contrast lumen.

[0127]

[0179] As mentioned, any of these devices may be configured to apply an external fluid through one or more buffer flow openings. For example, saline may be provided from a proximal source of saline and applied through one or more distal buffer flow openings. In some cases, the fluid forming the buffer flow region may be expelled from the internal navigation lumen and / or contrast lumen. In some instances, the external fluid may be a saline solution that may be injected into the aspiration (suction) lumen. The fluid may be pumped or drawn in by application of suction through the aspiration lumen, which may draw the external fluid from a proximal source into the aspiration lumen. As with any of these devices, the lumens of the device (e.g., aspiration lumen, navigation lumen, contrast lumen, etc.) may be filled with, for example, saline prior to the start of the procedure.

[0128]

[0180] 27A and 27B show examples of the use of external fluid. In FIG. 27A, the contrast lumen 2712 includes one or more buffer flow openings 2745 through which external fluid may be applied to form an interference flow region on the side of the aspiration lumen facing from the aspiration opening 2704. The contrast lumen may include a tube that is affixed within the aspiration lumen (or the side of the aspiration lumen), or the contrast lumen may be a movable tube or member that may be inserted / removed laterally. In FIG. 27A, the distal end region also includes buffer flow openings 2714, 2714'. Thus, as shown in FIG. 27A, the contrast lumen may be used to deliver a fluid (e.g., saline) into a continuous flow region that forms a buffer flow region. In FIG. 27A, the distal end of the aspiration lumen is closed, but the navigation lumen 2712 extends distally out of the device as well.

[0129]

[0181] In some examples, a lumen such as the contrast lumen may be configured as a dual-use lumen that may inject contrast agent outside the distal end of the device (out of the suction opening 2704) as well as provide an external fluid to provide buffer flow. In some examples, the shaft may be rotated or rotatable such that the orientation of the opening (e.g., buffer flow opening(s) 2745) may be adjusted based on whether the contrast lumen delivers contrast agent or buffer flow.

[0130]

[0182] FIG. 27B shows an example of a device in which the navigation lumen 2712 may be configured for use to deliver additional buffer flow. In FIG. 27B, the aspiration catheter may include one or more side openings 2747. The aspiration catheter shown in FIG. 27B also includes four offset buffer flow openings 2714, 2714' and a contrast lumen 2712. In use, the device may apply suction from the aspiration lumen and out of the aspiration opening 2704 to help prevent clot material from blocking the aspiration opening, and may apply fluid (e.g., saline) as part of a continuous flow (when applying suction) or on demand.

[0131]

[0183] 28A-28B show another example of a device configured to apply saline as part of the buffer flow fluid. The suction lumen may apply a continuous flow of fluid from the distal end region across at least the proximal half of the suction opening 2804 (and in some examples from the distal half or distal to the distal half of the suction opening) to roll and "peel" the clot material away without fragmenting it, so that if the clot material blocks the suction opening, it may be drawn into the suction lumen.

[0132]

[0184] In FIG. 28A, device 2800 is an aspiration catheter that includes an aspiration lumen 2816 extending distally to proximally. The catheter also includes a navigation lumen, which may be referred to as a continuous flow lumen, which may be incorporated into the shaft of the catheter or, in some instances, may be insertable. This navigation lumen 2812 may be configured to pass a guidewire 2811, as shown, or, in some instances, a navigation catheter (not shown). In FIG. 28A, a guidewire is inserted through the navigation catheter and extends distally out of distal opening 2816. In this instance, the navigation lumen (continuous flow lumen) may terminate at a distal end region of the distal tip prior to the distal end, such that the distal end 2857 of the navigation lumen is adjacent the distal end region of the aspiration opening 8204, adjacent the distal end of the aspiration opening, or adjacent just distal to the distal end of the aspiration opening. For example, the opening 2857 may be positioned opposite the suction orifice 2804 and may terminate somewhere between the proximal edge of the orifice and the area just distal to the distal edge of the suction orifice 2804.

[0133]

[0185] The distal tip of the device (distal end opening 2816) may be configured to allow a guidewire to exit the tip as shown, but may be closed and / or sealed over the end of the guidewire. For example, the inner diameter (ID) of the device's tip 2816 may be configured to allow a guidewire (e.g., 0.035 GW) to pass through the device, but restrict fluid flow (e.g., injected saline) distally exiting the tip. Alternatively, fluid may exit the distal end (with or without a guidewire) and be redirected by the inside of the distal tip region so that the fluid is directed proximally and extracted by the vacuum applied during clot removal.

[0134]

[0186] In some instances, the distal tip 2816 may be closed by a membrane or by a preset "pinch" that may allow passage of a guidewire (e.g., a 4F catheter or guidewire) to be inserted therethrough but may restrict fluid from exiting the tip. Any of these devices may include additional buffer flow openings (not shown in the example of FIG. 28A but present in FIG. 28B). FIG. 28B shows another example of an aspiration catheter 2800' in which the navigation lumen 2812 is configured to pass saline as part of the buffer flow. When suction is applied, the buffer flow may be provided through the buffer flow openings 2814, 2814' positioned as described above. In some cases, additional fluid may be applied through the navigation lumen on demand, for example, to help prevent clogging of the aspiration orifice 2804 or adhesion of clot material. For example, additional saline may provide a continuous flow that may help tumble and / or compress the clot material to prevent closure of the suction orifice.

[0135]

[0187] 29 and 30 show an alternative example of an aspiration catheter including a navigation lumen configured to pass saline as part of the buffer flow entering the distal end region of the catheter, similar to the example shown in FIGS. 28A and 28B. In FIG. 29, a navigation lumen 2912 extends into the distal end region of the aspiration catheter within the aspiration lumen such that a distal end 2957 of the navigation lumen is positioned opposite from the distal end of the aspiration aperture (aspiration opening 2904). A guidewire 2911 is shown extending through the navigation lumen 2912 and out of the distal tip 2916 of the aspiration catheter. As discussed with reference to FIGS. 28A-28B, the distal tip 2916 may be configured to close or seal to prevent fluid from passing but allow passage of a guidewire and / or guide catheter (e.g., a navigation catheter). In FIG. 29, the distal region of the navigation lumen 2912 may include one or more side openings (e.g., configured as buffer flow openings 2954 for passing fluids, such as saline, from the navigation lumen and into the aspiration lumen). These one or more side openings (in this example, multiple small side openings are shown) may be oriented outwardly from the suction opening 2904 to better help establish an opposing buffer flow region from the suction opening 2904. Additionally, as in FIGS. 28A-28B, the distal end 2957 of the navigation lumen may be open and may pass fluid and redirect fluid proximally when suction is applied into the suction lumen and / or when fluid is forced (by applying positive pressure) from the proximal end of the navigation lumen into the enclosed distal region 2922. Generally, one or more buffer flow openings 2954 (e.g., ports) on the navigation lumen may be configured to be positioned over the distal end region of the suction opening, as is generally true for buffer flow openings, thereby forming a buffer flow region extending along the long axis of the suction lumen to force blood clots to roll against the proximal edge region of the suction opening.

[0136]

[0188] FIG. 30 is similar to the example shown in FIG. 29 and includes a navigation lumen 3012 having a distal end opening 3507 positioned distal to or opposite the distal end region of the aspiration opening 2904. However, in FIG. 30, a side opening through the navigation catheter forms one or more elongated buffer flow openings 3054. As in FIG. 29, the aspiration catheter shown in FIG. 30 may be used with or without the presence of a guidewire in the navigation lumen. In general, the buffer flow opening(s) through the navigation lumen and into the aspiration lumen may have a variety of different shapes and sizes to allow fluid (e.g., saline) released from the navigation lumen to be dispersed at the distal tip region of the catheter opposite where the clot enters the aspiration opening.

[0137]

[0189] FIG. 31 shows another example of an aspiration catheter, where the device is configured such that fluid may be drawn from a distal region of the catheter, such as distal to the clot, through an internal lumen (e.g., similar to the navigation lumen) into the aspiration lumen. In this example, the aspiration catheter 3100 includes an expandable lumen 3159 that may extend distally out of the distal tip of the aspiration catheter. The expandable lumen may draw fluid from outside the catheter, e.g., distal to the clot, into the aspiration lumen and out of ports 3154 (e.g., one or more buffer flow openings) on the sides of the expandable lumen 3159. In some examples, areas of the expandable lumen proximal to these ports may be closed off, so that suction through the aspiration lumen may draw fluid from within the expandable lumen (and from areas within the vessel 3157 distal to the clot) into the aspiration lumen to form a buffer flow area adjacent the aspiration opening 3104. The expandable lumen may be advanced distally out of the aspiration catheter once the aspiration catheter is near the clot 3155 so that the lateral buffer flow opening is positioned adjacent to (or just distal to) the distal end of the aspiration opening. Thus, in this example, the lumen can be dynamically advanced distal to the clot 3155 and draw blood from the distal portion of the vessel 3157 into the aspiration tip to provide the fluid needed to move the clot and keep the catheter flowing during aspiration. As noted, the expandable lumen is closed at the proximal end to ensure that fluid is drawn from its distal opening. Suction chamber

[0138]

[0190] In addition to the catheter devices described herein, blood collection (aspiration) apparatus configured for reperfusion of collected blood is also described. Catheters and instruments for removal of thrombi from the vascular system may include an elongated suction catheter as described above. Suction may be applied through the catheter to aspirate thrombi from a target site in the vasculature, through the lumen of the device, and out of the body, where they may be collected. In some cases, aspiration / suction is provided by drawing a vacuum on an attached syringe. In other configurations, aspiration / suction is applied from a suction pump attached to the catheter.

[0139]

[0191] Described herein are blood collection chamber apparatus (devices, systems, etc., including blood collection devices) in which aspirated thrombus material and fluid blood may be collected for study and measurement. In particular, these apparatus may be configured to allow efficient and safe reperfusion of collected (and filtered) blood. In some configurations, a suction pump is connected to the blood collection chamber, which is then connected to a catheter. The collection chamber may include a valve or be coupled in-line with the device to selectively open a fluid path from the catheter to the chamber to allow application of aspiration / suction directly from the catheter (e.g., aspiration catheter). The blood collection chambers described herein may alternatively be referred to as vacuum chambers, vacuum accumulators, vacuum boxes, or vacuum reservoirs.

[0140]

[0192] The blood collection chamber may be configured to allow direct visualization of the collected clot and / or blood. For example, all or a portion of the blood collection chamber may be formed of a clear (transparent or at least translucent) material so that the collected blood and / or clot may be visualized. Any of these devices may be calibrated to indicate the volume of blood and / or clot collected. For example, the device may include graduations (e.g., markings) to allow measurement of the volume of aspirated material. Any of these devices may include one or more filters (e.g., coarse and / or fine filters) to separate the fluid blood from the fixed-semisolid clot that is collected. The filter(s), particularly the coarse filter, may be removable so that the filtered clot can be removed, washed (e.g., flushed with saline), measured, photographed, and / or physically examined by a physician, or used for further testing.

[0141]

[0193] In general, these devices may be configured to be sized to collect and hold a volume that is manageable within a surgical field, on a bed rail, or with an IV pole. Additionally, these devices may have a small enough volume to allow for rapid (e.g., in less than a minute) attainment of internal vacuum by a suction pump. These devices may have a large enough volume to provide sufficient vacuum buildup so that application of aspiration / suction in 5 second bursts does not reduce the chamber vacuum by more than 50%. These devices may be appropriately sized to not allow for excessive suction (which may risk exsanguining the patient). For example, these devices may be configured to limit blood removal to 500 cc or less of blood. In some instances, the blood collection chamber may be approximately 500 cc.

[0142]

[0194] Additionally, the blood collection device described herein may be configured to allow reperfusion of collected fluid blood. This may be nothing more than an openable lid that allows the collected fluid to be removed by a syringe and fine filter, but more specifically, the device described herein may be adapted to filter and treat the blood so that it can be used immediately and easily in an operating room near (or directly connected to) the patient, and to prevent bubble formation and / or turbulence of the blood. In some instances, the filtered blood may be configured to be drawn from the lower sidewall by a needleless syringe valve. This may allow the fluid blood to be removed from the blood collection device by a syringe for reperfusion to the patient through a blood return circuit placed in the vasculature. In some cases, the blood return circuit may be directly connected to the device.

[0143]

[0195] Any of these devices may be illuminated for enhanced visualization of blood and / or removed clots. Any of these devices may include a separate clot collection chamber in-line with the device. The device, particularly the clot collection portion (which may include a coarse filter), may be configured to measure the weight and / or volume of collected clot material.

[0144]

[0196] Any of these devices may be heated and / or cooled. In particular, the area of ​​the device configured to collect blood may be temperature regulated. As described in detail below, the device may generally include an upper chamber configured to be charged with vacuum and connected in-line with a suction catheter, the upper chamber being fluidly connected to a lower blood collection area configured to be in communication with the reperfusion section. Blood may generally be configured to be transferred by gravity between the upper chamber (upper canister or vacuum chamber) and the lower chamber (lower canister or blood collection chamber). In some examples, the upper and lower chambers may be formed in the same (or different) canister and may be separated by one or more passive or active valves that maintain a negative pressure (e.g., vacuum) in the upper chamber and only allow blood to flow to the lower chamber when the pressure between the two chambers is normalized to prevent or limit blood bubble formation.

[0145]

[0197] Any of these blood collection devices may be configured to allow for the introduction of medications such as, for example, heparin. Any of these devices may be configured to allow for saline flushing. In some instances, the device may include one or more sealable but retractable lids or doors to allow the contents to be manually emptied and / or cleaned.

[0146]

[0198] Generally, these devices may be configured to operate safely and provide a fail-safe mode in which one or more automatic or automatic shut-off valve(s) are included such that suction into the device through the catheter is stopped when the blood collection chamber reaches a critical collection volume of blood to be collected. This may include the use of sensors, including mechanical and / or electrical sensors. In some examples, the device may include a float valve that blocks the suction outlet when the contents are positioned proximate to the suction outlet.

[0147]

[0199] In general, there is an unmet need for a blood collection device having a vacuum chamber that allows for the collection of blood and the perfusion of the blood to a patient. Currently available blood collection chambers typically collect blood in the same chamber as the vacuum. This may cause the collected blood to degas and form bubbles. This may also result in a level of hemolysis. Additionally, this may require a larger volume of the vacuum chamber and require longer time to charge the chamber before and during use. The blood collection devices described herein may be particularly useful for collecting blood in a vacuum chamber while minimizing the level of vacuum applied to the blood and / or the time the blood is held under vacuum. The blood collection devices described herein may be further configured to allow storage of blood in a vacuum canister so that the blood may be reperfused efficiently and with minimal risk of damage to the blood or harm to the patient.

[0148]

[0200] FIG. 32 illustrates an example of a blood collection device configured for reperfusion. In this example, the blood collection device is configured for use with a thrombus aspiration catheter, such as (but not limited to) the aspiration (e.g., suction) catheters described in FIGS. 1-21. In FIG. 32, the device may optionally include a vacuum source (e.g., vacuum pump 3221) that may be connected to a vacuum line 3219. The vacuum line 3219 connects to an outlet of a vacuum canister 3225, in this example, through a vacuum outlet 3218. The vacuum canister 3225 has a vacuum release valve 3217 (selectively opens / closes the valve to atmosphere). The canister 3225 is divided into an upper chamber portion 3241 and a lower chamber portion 3243, which in this example are separated by a permeable solid / liquid filter 3223 that divides the canister 3225 into an upper portion and a lower portion. Solids may be collected in the upper portion of the filter. Fluids may pass through the filter and be collected in the lower portion of the canister. The canister has a suction inlet 3215. A suction line 3211 connects to the suction inlet. There is an on / off valve 3213 on the suction line (or at the suction inlet). The suction line may connect to a suction catheter that is inserted into the vasculature and positioned at the target / treatment site. The device also includes a reperfusion valve 3227 (which may be coupled to or form part of the reperfusion outlet) at the bottom and / or bottom sidewall of the canister. The reperfusion line, which is in communication with the fluid-collecting lower portion of the canister, may be coupled to a reperfusion circuit or a collection / delivery container (e.g., bag, syringe, etc.). In FIG. 32, the reperfusion line 3231 is connected to the reperfusion valve (and may be connected to the blood return circuit), as well as in-line with a fine filter that may be used to further remove blood impurities.

[0149]

[0201] In some examples, as shown in FIGS. 33A-33E, a blood collection device such as that shown in FIG. 32 may first turn on the pump (vacuum source 3321) and pump the canister 3225 to a desired vacuum level (e.g., 1.01325×10 5It may be used with the suction catheter by "charging" it to a vacuum of less than 1 Pa (atm) (FIG. 33B). Alternatively, the vacuum may remain on but at a reduced level and / or may be configured to maintain the vacuum at a predetermined level within the canister; any of these devices may include a sensor to detect the pressure within the upper region of the canister. The canister may be free of all solids and fluids at the start of the procedure (FIG. 33A). Once charged, the pump may be turned off, retaining the charged vacuum within the canister. Once the suction catheter is positioned at the target site within the vasculature, the suction valve 3313 may be opened and fluid blood 3343 and thrombus material (clot material) 3344 may be drawn out of the vasculature, through the suction catheter and suction line, and into the canister (FIG. 33C). As shown in FIG. 33D, clot material 3344 from the suction catheter may collect at the top of the suction filter (e.g., coarse filter) 3323, while fluid (e.g., blood 3343) may pass through the filter and collect in the lower portion of the canister. At various times during the procedure, suction may be reduced or turned off by closing the suction valve 3313. Suction may be repeated until the physician has removed all the desired clots, or until the canister reaches its maximum fill point or a maximum amount of fluid blood has been aspirated, or until the canister reaches its maximum holding condition, or until the "vacuum charge" in the canister is depleted to a minimum level. Once the procedure is completed and / or it is determined to stop or pause suction, the suction valve 3313 may be closed and the blood intended for reperfusion, now stored in the lower portion of the canister under vacuum conditions, may be prepared for reperfusion. For example, the vacuum release valve 3317 may be opened to reduce the canister vacuum to a minimum or return it completely to atmospheric conditions (FIG. 33E). The reperfusion valve 3327 may then be opened and the collected fluid blood may be returned to the patient.The reperfusion valve 3327 may then be closed and the solid clot material 3344 may be removed (e.g., in this example, an optional lid or door may be opened to allow removal of the solid clot and / or solid / fluid filter with clot). For example, the clot (clot material) may be flushed with saline, inspected, measured, cleaned from the coarse filter 3323. The filter may be replaced and the lid or door may be closed. The vacuum release valve 3317 may then be closed, the suction pump may recharge the vacuum in the canister, and the physician may perform further suction thrombectomy.

[0150]

[0202] As mentioned, in some cases, the suction pump 3321 can be left running continuously until the atmospheric valve opens. In some cases, the atmospheric valve can be selectively opened to minimize the amount or time that the fluid blood is held under vacuum conditions.

[0151]

[0203] In general, it will be particularly useful to divide the vacuum canister into separate vacuum and blood collection portions. For example, the devices of Figs. 32 and 33A-33E may include an additional partition after the coarse filter. This partition may divide the canister into an upper or vacuum chamber and a lower or blood storage chamber. The partition may include one or more one-way valves that, when opened, allow fluid blood to pass from the vacuum chamber to the blood storage chamber. The one-way valves may be configured and / or controlled to open automatically (e.g., spontaneously).

[0152]

[0204] In some examples, the lower chamber (e.g., blood storage chamber) may include a pressure adjustment opening. In some examples, the pressure adjustment opening is a small hole or opening that opens to the atmosphere. In some examples, the pressure adjustment opening may be a valved opening that allows control of the pressure in the lower chamber. As such, the device may include one or more sensors for detecting the pressure in the lower chamber. A one-way valve (which may be referred to herein as a partition valve) is typically positioned in the partition between the upper and lower chambers. In some examples, the partition valve may operate automatically by allowing fluid blood to pass from the upper (vacuum) chamber into the lower chamber by the fluid's own weight, which may deflect the one-way valve to open. When the upper chamber (vacuum chamber) is charged with a vacuum and the lower chamber is opened to the atmosphere, the one-way valve may be held closed by the pressure difference between the lower chamber at atmospheric pressure and the upper chamber at vacuum.

[0153]

[0205] For example, FIG. 34 shows an example of a blood collection device that includes a canister partitioned into an upper chamber 3441 for holding a vacuum and a lower chamber 3443 for holding filtered blood. As in FIG. 32, the device may include or be configured to couple to a vacuum source 3421 that applies a vacuum to charge the upper (vacuum) chamber 3441. The vacuum source may be coupled to the upper chamber by a vacuum line 3419 through a vacuum outlet 3418 coupled to the upper chamber. The upper (e.g., vacuum) chamber may include a vacuum release valve 3417 and may be charged with a vacuum by the vacuum source. The upper chamber may be coupled to a suction line that connects to a suction catheter. In FIG. 34, the suction line may be coupled to the upper chamber by a suction inlet 3415, and the vacuum applied to the suction catheter may be regulated by a suction inlet valve 3413.

[0154]

[0206] The coarse filter 3423 may be in-line with the upper chamber 3441. In the example shown in FIG. 34, the coarse filter 3423 is in the upper chamber. In some examples, the coarse filter is coupled in-line with the aspiration line prior to the upper chamber. The device also includes a partition 3442 that separates the upper chamber from the lower chamber. In the example shown in FIG. 34, the partition includes a partition valve 3433 that is a one-way valve, and the partition valve 3433 may be configured to automatically open when pressure between the upper and lower chambers is normalized and when blood is present in the upper chamber. In some examples, the partition valve may be controlled to open (or manually opened), for example, by a controller that may determine when blood is present in the upper chamber and cause pressure between the upper and lower chambers to normalize. For example, the controller (blood collection controller) may control the vacuum release valve 3417, the vacuum pump (or vacuum pump valve, not shown in FIG. 34, between the vacuum source 3421 and the vacuum outlet 3418), and the opening of the pressure adjustment opening 3445 in the lower chamber. The lower chamber may be slightly larger than the upper chamber (e.g., the upper chamber may have a volume of about 400 ml, while the lower chamber has a volume of about 500 ml, etc.).

[0155]

[0207] The lower blood collection chamber 3443 may include a pressure regulating opening 3445 as described above; in some instances, the pressure regulating opening is an opening to atmosphere. The lower chamber may be fluidly connected to a reperfusion valve 3477 that connects the lower chamber to the reperfusion line 3431. A fine filter 3429 may be within the lower chamber or in-line with the lower chamber (e.g., with the reperfusion line).

[0156]

[0208] For example, suction thrombectomy may be performed as described above using a blood collection device for reperfusion similar to the embodiment shown diagrammatically in FIG. 34. In this example, the upper chamber may be charged with a vacuum. The vacuum chamber (lower chamber) may be charged relatively quickly because the upper chamber may be relatively small (e.g., less than 400cc volume, less than 350cc volume, less than 300cc volume, less than 250cc volume, less than 200cc volume, less than 150cc volume, etc.) compared to the total volume of the device (including the lower chamber volume, e.g., 400cc volume or more, 450cc volume or more, 500cc volume or more, etc.). The suction inlet valve may be controlled to apply a vacuum to a catheter coupled to the suction line 3411 to remove fluid and clot material. Blood may be collected and passed through a coarse filter 3423 to collect clot material 3444. In some examples, the system may periodically normalize the pressure between the upper chamber 3441 and the lower chamber 3443 to allow blood in the upper chamber to pass into the lower chamber where the blood may be stored. For example, the device may turn off the vacuum (or prevent vacuum from being applied to the upper chamber) and open the vacuum release valve 3317. The lower chamber may be maintained at atmospheric pressure. Once the pressures in the upper and lower chambers are normalized relative to one another to be approximately the same, the partition valve 3442 may open and blood may pass from the upper chamber to the lower chamber. Blood may be drained out of the upper vacuum compartment of the canister and then held in the atmospheric lower chamber.

[0157]

[0209] This configuration may be particularly advantageous since the vacuum portion of the canister may be minimized since it is not required to store a volume of fluid blood during reperfusion. The smaller vacuum chamber may be charged to vacuum more quickly due to its optimized volume. Blood may be stored in the lower canister at atmospheric pressure, thus minimizing the time spent under vacuum and allowing the physician to reperfuse the blood at a time of their choosing (e.g., blood may be removed via a reperfusion line). Blood at atmospheric pressure in the storage chamber may be regassed and degassed prior to reperfusion.

[0158]

[0210] The one-way partition valve 3442 may be configured to remain closed when it separates the lower (e.g., atmospheric) chamber from the upper (e.g., vacuum) chamber portion. Upon release of some or all of the vacuum chamber negative pressure, the partition valve may spontaneously open under the fluid weight of the collected blood. For example, in one example, the one-way partition valve opens under a minimum hydrostatic pressure (e.g., the pressure exerted by a fluid at equilibrium at a given point within the fluid due to the force of gravity).

[0159]

[0211] The hydrostatic pressure may be minimal, e.g., less than 5 mmHg of fluid height. In some embodiments, the hydrostatic pressure that opens the one-way valve, e.g., the "crack pressure," may be greater than the hydrostatic pressure required to keep the one-way partition valve open. This will allow for more complete emptying of the fluid blood. In some embodiments, the one-way partition valve is configured to open under the fluid weight of blood, even when some partial vacuum exists in the evacuated canister.

[0160]

[0212] Examples of various one-way valves and how they may function as partition valves are shown in the following table, where the partition valves are umbrella valves of various diameters and with various drain hole patterns. [Table 1]

[0161]

[0213] In this example test, configuration #2 showed the best performance in crack pressure combined with drain flow rate. Figures 35A-35B show an example of an umbrella valve as described herein. In Figure 35A, the valve is shown closed. Figure 35B shows the valve open; when the force pushing down on the valve due to the weight of blood in the upper chamber exceeds the crack pressure of the valve, the valve will open and blood may flow down. Note that if the pressure is not normalized (approximately equal) between the upper and lower chambers, the valve will not open.

[0162]

[0214] 36A-36E show the operation of a blood collection device similar to that shown in FIG. 34. In this example, the device includes an upper chamber 3441 and a lower chamber 3443, where the upper chamber (vacuum chamber) is opened when the pump (vacuum source 3421) is turned on and a desired vacuum level (e.g., 1.01325×10 5The upper chamber 3441 may be initially charged with vacuum by "charging" it to a vacuum of less than 1 Pa (1 atm) (FIG. 36B). Once charged, the vacuum may be turned off, or alternatively, the vacuum may be left on but at a reduced level or directed outward (by a valve) from the vacuum chamber. Any of these devices may include a sensor to detect pressure in the upper chamber, which may be used for control feedback. The upper and lower chambers may be initially emptied of all solids and fluids at the start of the procedure (FIG. 36A). Once charged, the pump may be turned off, keeping the charged vacuum in the upper chamber. Once the aspiration catheter is positioned at the target site within the vasculature, the aspiration valve 3413 may be opened and fluid blood 3443 and thrombus material (clot material) 3444 may be drawn out of the vasculature, through the aspiration catheter and aspiration line, and into the upper chamber (FIG. 36C). Clot material 3444 from the suction catheter may collect at the top of the suction filter (e.g., coarse filter) 3423, as shown in FIG. 36D, while fluid (e.g., blood 3443) may pass through the filter and temporarily collect at the bottom of the upper chamber. At various times during surgery, suction may be reduced or turned off by closing the suction valve 3413, and the pressure between the upper and lower chambers may be normalized. For example, if the lower chamber includes an opening to the atmosphere (e.g., a pressure regulation opening), the vacuum release valve 3417 may be opened to set both the upper and lower chambers to approximately the same pressure (e.g., atmospheric pressure). This allows the partition valve 3433 to open, as shown in FIG. 36E, so that blood in the upper chamber may be drained (by gravity) into the lower chamber for storage. Once drained, the partition valve may close again, the upper chamber may be recharged with vacuum, and suction may continue. At any time thereafter, including when suction is performed or applied, blood may be removed from the lower chamber via reperfusion line 3431, for example, by opening reperfusion valve 3427.

[0163]

[0215] Suction may continue by repeating the above steps. Once the procedure is finished and / or it is decided to stop or pause suction, the vacuum release valve 3417 may be opened and the solid clot material 3444 may be removed (e.g., in this example, an optional lid or door may be opened to allow removal of the solid clot and / or solid / fluid filter with clot). For example, the clot (clot material) may be flushed with saline, inspected, measured, cleaned from the coarse filter 3423. The filter may be replaced and the lid or door may be closed. The vacuum release valve 3417 may then be closed, the suction pump may recharge the vacuum in the canister, and the physician may perform further suction thrombectomy procedures.

[0164]

[0216] FIG. 37 shows another example of a schematic diagram of a device for collecting blood for reperfusion, similar to that shown in FIG. 34. This example also includes a canister partitioned into upper and lower chambers 3741 and 3743 separated by a partition and partition valve 3733; however, in this example, the coarse filter is part of a separate clot filtration (coarse filtration) chamber 3757 coupled in-line with and upstream of the upper chamber 3741. The clot filtration chamber may be configured (e.g., in a planar configuration) to allow direct visualization of the clot material 3744 as it is filtered, and may connect distally to an aspiration line 3711 that connects to an aspiration catheter, and proximally to an aspiration inlet 3715 (or inlet valve 3713) that leads to the upper chamber 3741. The filtration chamber 3757 may be opened to allow removal of clot material from the coarse filter without collapsing the device. 37 also includes a reperfusion valve 3727 and a reperfusion line 3731 as well as a partition valve 3733 and a partition 3742 between the upper and lower chambers. A vacuum source 3721 may optionally be coupled to the upper chamber through a vacuum outlet 3718. The upper chamber may include a vacuum release valve 3717.

[0165]

[0217] In use, a blood collection device such as that shown in FIG. 34 and FIG. 37 may be used as described above. For example, FIG. 38 shows generally one method of reperfusing blood during a clot removal procedure. In this example, the upper chamber of the reperfusion system may be charged with vacuum (e.g., to a desired negative pressure / vacuum) 3802, for example, by turning on a vacuum source and opening a vacuum valve to couple the vacuum source to the upper chamber. Once the upper chamber is charged with vacuum, a suction catheter (e.g., aspiration catheter) may be used to remove the clot material (and blood) 3804 by opening a suction valve between the suction catheter and the upper channel. Once removed, the clot material may be filtered from the blood by a coarse filter that is in-line with or within the upper chamber 3806. At any point in this process, blood may be transferred from the upper chamber into the lower blood storage chamber 3808 by normalizing the pressure between the upper and lower chambers. For example, both the upper and lower chambers may be normalized to atmospheric pressure by opening the vacuum release valve in the upper chamber and the pressure regulation opening in the lower chamber (both may be constantly open or open / closed). Once the pressure is normalized, the partition valve between them may be opened, allowing blood to drain between the upper and lower chambers; the partition valve may then be closed and the upper chamber may be recharged 3812, allowing the aspiration procedure to continue, repeating the steps of aspirating and then draining blood from the upper chamber to the lower chamber. The collected blood may be kept warm or cooled and at atmospheric pressure so that it can degas; at any point, the collected blood may be removed through a reperfusion line and returned to the patient's body 3810.

[0166]

[0218] It should be appreciated that all combinations of the above concepts, and further concepts discussed in more 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.

[0167]

[0219] The process parameters and sequences of steps described and / or illustrated herein are given by way of example only and may be varied as desired. For example, although the steps illustrated and / or described herein may be shown or discussed in a particular order, these steps do not necessarily have to be performed in the order shown or discussed. The various example methods described and / or illustrated herein may omit one or more of the steps described or illustrated herein or include additional steps in addition to those disclosed.

[0168]

[0220] 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 executable by a processor (e.g., computer, tablet, smartphone, etc.) that, when executed by the processor, causes the processor to perform any of the steps, including, but not limited to, displaying, communicating with a user, analyzing, modifying parameters (including timing, frequency, intensity, etc.), determining, alerting, or the like. For example, any of the methods described herein may be at least partially performed 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 process(es) of the method. The various exemplary methods described and / or illustrated herein may omit one or more of the steps described or illustrated herein or include additional steps in addition to those disclosed. Additionally, the steps of any of the methods disclosed herein may be combined with any one or more steps of any other method disclosed herein. The processors described herein may be configured to perform one or more steps of any of the methods disclosed herein. Alternatively, or in combination, the processors may be configured to combine one or more steps of one or more of the methods disclosed herein.

[0169]

[0221] When a feature or element is referred to herein as "on" another feature or element, it can be directly on the other feature or element, or there may be intervening features and / or elements. In contrast, when a feature or element is referred to herein as being "directly on" another feature or element, there are no intervening features or elements present. When a feature or element is referred to as being "connected," "attached," or "coupled" to another feature or element, it will also be understood that it may be directly connected, attached, or coupled to the other feature or element. 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 illustrated with respect to one embodiment, the features or elements so described or illustrated may apply to other embodiments. It will also be recognized by those skilled in the art that a reference to a structure or feature being disposed "adjacent" to another feature may have portions that overlap or underlie the adjacent feature.

[0170]

[0222] The terms used herein are merely for the purpose of describing particular embodiments and are not intended to limit the invention. For example, as used herein, the singular forms "a", "an" and "the" are intended to include the plural unless the context clearly dictates otherwise. It will be further understood that the terms "comprises" and / or "comprising", as used herein, 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 " / ".

[0171]

[0223] Spatially relative terms such as "under," "below," "lower," "over," "upper," and the like may be used herein for ease of description to describe the relationship of one element or feature to another element(s) or feature(s) shown 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 shown in the figures. For example, if the device in the figures is inverted, an element described as "under" or "beneath" the other element or feature would then be oriented "over" the other element or feature. Thus, the exemplary term "under" can encompass both an orientation of directly above and directly below. The device may be otherwise oriented (rotated 90 degrees or in other orientations) and the spatially relative descriptors used herein will be interpreted accordingly. Similarly, the terms "upwardly," "downwardly," "vertical," "horizontal," etc. are used herein for descriptive purposes only, unless specifically indicated otherwise.

[0172]

[0224] The terms "first" and "second" may be used herein to describe various features / elements (including steps), but these features / elements should not be limited by these terms unless the context dictates otherwise. These terms may be used to distinguish one feature / element from another. Thus, a first feature / element discussed below could be referred to as a second feature / element, and similarly, a second feature / element discussed below could be referred to as a first feature / element without departing from the teachings of the present invention.

[0173]

[0225] Throughout this specification and the appended claims, unless the context requires otherwise, the words "comprise" and variations such as "comprises" and "comprising" refer to various components that may be used in conjunction together in methods and articles (e.g., devices and compositions and apparatuses that include methods). For example, it will be understood that the term "comprising" implies the inclusion of any stated element or step, but not the exclusion of any other elements or steps.

[0174]

[0226] In general, any of the apparatus and methods described herein should be understood to be inclusive, although all or a subset of the components and / or steps may alternatively be exclusive and may be expressed as "consisting of" or alternatively "consisting essentially of" various components, steps, subcomponents, or substeps.

[0175]

[0227] As used in the specification and claims, including as used in the examples, and unless expressly specified otherwise, all numbers may be read as if they are preceded by the word "about" or "approximately", even if the term does not explicitly appear. The phrase "about" or "approximately" may be used when describing a magnitude and / or location to indicate that the described value and / or location is within an expected reasonable range of values ​​and / or locations. For example, a numerical 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 value given herein should be understood as indicating about or approximately that value, unless the context dictates otherwise. For example, if the value "10" is disclosed, then "about 10" is also disclosed. Any numerical ranges recited herein are intended to include all subranges subsumed in the numerical range. When a value is disclosed, it is also understood that "less than or equal to the value," "greater than or equal to the value," and possible ranges between the values ​​are also disclosed, as would be understood by one of ordinary skill in the art. For example, if a value "X" is disclosed, "less than or equal to X" as well as "greater than or equal to X" (e.g., where X is a number) are also disclosed. It is also understood that data are provided throughout the application in a number of different formats, and that this data indicates endpoints and starting points, as well as ranges for any combination of the data points. For example, if a specific data point "10" and a specific data point "15" are disclosed, it is understood that greater than, greater than, less than, less than, and equal to 10, and greater than, greater than, less than, less than, and equal to 15, as well as between 10 and 15, are also possible. It is also understood that each unit between two specific units is also disclosed.For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

[0176]

[0228] Although various illustrative embodiments are described above, any of numerous modifications may be made to the various embodiments without departing from the scope of the present invention as described by the claims. For example, the order in which the various method steps described are performed may often be changed in alternative embodiments, and in other alternative embodiments, one or more method steps may be skipped entirely. Optional features of the various device and system embodiments may be included in some embodiments and not in other embodiments. Thus, the above description is provided primarily for illustrative purposes and should not be construed as limiting the scope of the present invention, as the scope of the present invention is set forth in the claims.

[0177]

[0229] The examples and illustrations contained herein show, by way of illustration and not by way of limitation, specific embodiments in which the subject matter may be practiced. As stated, other embodiments may be utilized and derived therefrom, whereby structural and logical substitutions and modifications may be made without departing from the scope of the present disclosure. Such embodiments of the subject matter of the present invention may be referred to herein, individually or collectively, simply by the term "invention" for convenience and without intending to spontaneously limit the scope of the present application to any single invention or inventive concept when more than one is actually disclosed. Thus, although specific embodiments have been shown and described herein, any arrangement presumed to achieve the same purpose may be substituted for the specific embodiments shown. The present disclosure is intended to cover any and all adaptations and variations of the various embodiments. Combinations of the above embodiments, as well as other embodiments not specifically described herein, will be apparent to those skilled in the art upon reviewing the above description.

Claims

1. A suction catheter device, A long, slender body having a suction tube lumen, A distal end region extending from the elongated body, having a suction opening that extends along the tapered length of the side surface of the distal end region, The system comprises one or more buffer flow openings that penetrate the surface of the distal end region opposite to the suction opening, wherein the one or more buffer flow openings collectively have geometric centers along the length of the side surface of the distal end region, which are within + / - 20% of the longitudinal center of the suction opening. A suction catheter device wherein one or more buffer flow openings are configured to apply a rotational force to the blood clot material, push the blood clot material toward the proximal edge of the suction opening, cut an elongated strip from the blood clot material, and accompany the elongated strip so that it is drawn proximal to the lumen of the suction tube.

2. The suction catheter device according to claim 1, wherein the collective geometric center of the one or more buffer flow openings is within + / - 10% of the longitudinal center of the suction opening.

3. The suction catheter device according to claim 1, wherein the collective geometric center of the one or more buffer flow openings is located at the longitudinal center of the suction opening or distal to the longitudinal center.

4. The suction catheter device according to claim 1, wherein at least one of the one or more buffer flow openings is located distal to the longitudinal center of the suction opening.

5. The suction catheter device according to claim 1, wherein the one or more buffer flow openings comprise a number of buffer flow openings between 2 and 20.

6. The suction catheter device according to claim 1, further comprising a shroud extending from the outer surface of the elongated body opposite to the suction opening distal to the buffer flow opening, wherein the shroud is configured to prevent blood clot material from entering the buffer flow opening.

7. The suction catheter device according to claim 1, wherein the one or more buffer flow openings are positioned between 60 degrees and 120 degrees from the longitudinal centerline passing through the suction opening.

8. The suction catheter device according to claim 1, further comprising a navigation lumen that extends adjacent to the suction lumen along the distal end region, opposite to the suction opening.

9. The suction catheter device according to claim 8, wherein one or more buffer flow openings extend through the navigation lumen.

10. The suction catheter device according to claim 8, wherein the one or more buffer flow openings comprises two or more buffer flow openings located on both sides of the navigation lumen.

11. The suction catheter device according to claim 1, wherein the ratio of the area of ​​the suction opening to the combined area of ​​the one or more buffer flow openings is between 10:1 and 16:

1.

12. The suction catheter device according to claim 1, wherein the ratio of the area of ​​the suction opening to the combined area of ​​the one or more buffer flow openings is between 12:1 and 14:

1.

13. The suction catheter device according to claim 1, further comprising a displacement projection extending from the outer surface of the distal end region, configured to displace the outer opening of one or more buffer flow openings from the wall of the blood vessel into which the distal end region is inserted.

14. The suction catheter device according to claim 1, wherein the suction opening comprises a reinforced lip region surrounding at least the proximal edge of the suction opening.

15. The suction catheter device according to claim 1, wherein the suction opening is configured such that the diameter of the suction lumen at the distal edge of the suction opening is 40% or more of the diameter of the suction lumen at the proximal edge of the suction opening.

16. A suction catheter device, A long, slender body having a suction tube lumen, A distal end region extending from the elongated body, having a suction opening that extends along the tapered length of the side surface of the distal end region, The system comprises one or more buffer flow openings that penetrate the surface of the distal end region facing the suction opening and / or the distal end of the distal end region, wherein the one or more buffer flow openings collectively have geometric centers located distal to the longitudinal center of the suction opening, along the length of the side surface of the distal end region, A suction catheter device wherein one or more buffer flow openings are configured to apply a rotational force to the blood clot material, pushing the blood clot material so that it strikes the proximal edge of the suction opening, and cutting an elongated strip from the blood clot material.

17. A suction catheter device, A long, slender body having a suction tube lumen, A distal end region extending from the elongated body, having a suction opening that extends along the tapered length of the side surface of the distal end region, A suction catheter device comprising a plurality of buffer flow openings between 2 and 20 that penetrate the surface of the distal end region opposite to the suction opening, wherein the plurality of buffer flow openings collectively have geometric centers along the length of the side surface of the distal end region, either at the longitudinal center of the suction opening or distal to the longitudinal center, and the plurality of buffer flow openings are configured to apply a rotational force to the blood clot material, pushing the blood clot material toward the proximal edge of the suction opening, and cutting an elongated strip from the blood clot material.

18. A suction catheter device, A long, slender body having a suction tube lumen, A distal end region extending from the elongated body, having a suction opening that extends along the tapered length of the side surface of the distal end region, A suction catheter device comprising a plurality of buffer flow openings between 2 and 20 that penetrate the surface of the distal end region opposite to the suction opening, wherein the plurality of buffer flow openings collectively have geometric centers along the length of the side surface of the distal end region, either at the longitudinal center of the suction opening or distal to the longitudinal center, the ratio of the area of ​​the suction opening to the combined area of ​​the plurality of buffer flow openings is between 12:1 and 14:1, and further comprising a plurality of buffer flow openings configured to apply a rotational force to the blood clot material, pushing the blood clot material toward the proximal edge of the suction opening, and cutting an elongated strip from the blood clot material.

19. A suction catheter device, A long, slender body having a suction tube lumen, A distal end region extending from the elongated body, having a suction opening that extends along the tapered length of the side surface of the distal end region, The system comprises a plurality of buffer flow openings that penetrate the side surface of the distal end region facing the suction opening, wherein at least one of the plurality of buffer flow openings is located distal to the longitudinal center of the suction opening. The suction opening is configured such that the diameter of the suction lumen at the distal edge of the suction opening is 40% or more of the diameter of the suction lumen at the proximal edge of the suction opening. A suction catheter device wherein the plurality of buffer flow openings are configured to form a buffer flow region inside the suction lumen opposite the suction opening in order to apply a rotational force to the blood clot material.

20. The aspiration catheter device according to claim 19, wherein the plurality of buffer flow openings comprises a number of buffer flow openings between 2 and 20.

21. The suction catheter device according to claim 19, further comprising a navigation channel having a lumen extending inside the suction lumen and configured to at least partially occlude the plurality of buffer flow openings.

22. The suction catheter device according to claim 19, wherein the plurality of buffer flow openings are positioned between 60 degrees and 120 degrees from the longitudinal center line passing through the suction opening.

23. The suction catheter device according to claim 19, further comprising a navigation lumen that extends adjacent to the suction lumen along the distal end region, opposite to the suction opening.

24. The suction catheter device according to claim 23, wherein one or more further buffer flow openings extend through the navigation lumen.

25. The suction catheter device according to claim 23, wherein the plurality of buffer flow openings comprises two or more buffer flow openings located on both sides of the navigation lumen.

26. The suction catheter device according to claim 23, wherein the navigation lumen is configured to have a distal end opening inside the suction lumen proximal to the distal tip region of the navigation lumen.

27. The suction catheter device according to claim 19, wherein the ratio of the area of ​​the suction opening to the combined area of ​​the plurality of buffer flow openings is between 10:1 and 16:

1.

28. The suction catheter device according to claim 19, wherein the ratio of the area of ​​the suction opening to the combined area of ​​the plurality of buffer flow openings is between 12:1 and 14:

1.

29. The suction catheter device according to claim 19, wherein the suction opening comprises a reinforced lip region surrounding at least the proximal edge of the suction opening.

30. The suction catheter device according to claim 19, wherein the suction opening is wider at the proximal end than at the distal end.

31. The suction catheter device according to claim 19, further comprising a hold-up region distal to the suction opening at the distal end of the suction lumen.

32. A suction catheter device, A long, slender body having a suction tube lumen, A distal end region extending from the elongated body, having a suction opening that extends along the tapered length of the side surface of the distal end region, The system comprises a plurality of buffer flow openings that penetrate the side surface of the distal end region facing the suction opening, wherein at least one of the plurality of buffer flow openings is located distal to the longitudinal center of the suction opening. The suction opening is configured such that the diameter of the suction lumen at the distal edge of the suction opening is 40% or more of the diameter of the suction lumen at the proximal edge of the suction opening. A suction catheter device wherein the plurality of buffer flow openings are configured to form buffer flow regions inside the suction lumen opposite the suction opening, apply a rotational force to the blood clot material, push the blood clot material so that it strikes the proximal edge of the suction opening, and cut an elongated strip from the blood clot material without fragmenting it.

33. A device for perfusing collected blood, Upper chamber and Lower chamber and A coarse filter between the upper chamber and the lower chamber, configured to capture blood clots, A vacuum inlet, which enters the upper chamber and is configured to be coupled to a vacuum source, A suction inlet that enters the upper chamber is configured to connect to the suction line through a suction valve, A reperfusion outlet from the lower chamber is configured to connect to the reperfusion line via a reperfusion valve, The upper chamber is equipped with a vacuum release valve that is in fluid communication with the upper chamber, The reperfusion valve is a device configured to open when the vacuum release valve opens.

34. The device according to claim 33, further comprising a microfilter in fluid communication with the reperfusion outlet.

35. The device according to claim 33, wherein the coarse filter is configured to be manually removed from the upper chamber by opening the top of the upper chamber.

36. The device according to claim 33, further comprising an impermeable partition between the upper chamber and the lower chamber, and a partition valve configured to form an opening through the impermeable partition.

37. The device according to claim 36, wherein the one or more partition valves comprises one or more umbrella valves configured to open when the fluid pressure acting on the valve exceeds the crack pressure.

38. The device according to claim 33, wherein the lower chamber is provided with a pressure regulator opening.

39. The device according to claim 38, wherein the pressure regulator opening is configured to exhaust to the atmosphere.

40. The device according to claim 33, wherein the upper and lower chambers are configured to allow direct visualization of blood through the walls of the upper and lower chambers.

41. The device according to claim 33, further comprising a reperfusion fluid line in fluid communication with the reperfusion outlet through a reperfusion valve.

42. The device according to claim 33, further comprising a vacuum source coupled to the vacuum inlet.

43. The device according to claim 33, wherein the reperfusion valve is configured to open only when the vacuum release valve is opened.

44. A device for perfusing collected blood, Upper chamber and Lower chamber and An impermeable partition between the upper chamber and the lower chamber, A partition valve configured to penetrate the impermeable partition and form an opening, A vacuum inlet, which enters the upper chamber and is configured to be coupled to a vacuum source, The suction port that enters the upper chamber, The reperfusion outlet exiting from the lower chamber, The lower chamber is equipped with a pressure regulating opening that enters the lower chamber, configured to maintain the pressure inside the lower chamber at a level greater than the pressure inside the upper chamber and exceeding the pressure required for blood bubble formation. The partition valve is configured to open to allow blood to flow from the upper chamber into the lower chamber.

45. The device according to claim 44, further comprising a coarse filter in fluid communication with the upper chamber.

46. The device according to claim 45, wherein the coarse filter is removable to allow manual clearance of the blood clot.

47. The device according to claim 44, further comprising a blood clot collection and visualization chamber having the coarse filter and being in fluid communication with the upper chamber through the suction inlet.

48. The device according to claim 44, wherein the pressure regulating opening is an opening to the atmosphere.

49. The device according to claim 44, wherein the pressure regulating opening is provided with a valve that controllably connects the lower chamber to a negative pressure source.

50. The device according to claim 44, further comprising a vacuum release valve in fluid communication with the upper chamber.

51. The device according to claim 44, wherein the one or more partition valves comprises one or more umbrella valves configured to open when the fluid pressure acting on the valve exceeds the crack pressure.

52. The device according to claim 44, wherein the upper and lower chambers are configured to allow direct visualization of blood through the walls of the upper and lower chambers.

53. The device according to claim 44, further comprising a reperfusion fluid line in fluid communication with the reperfusion outlet through a reperfusion valve.

54. The device according to claim 44, further comprising a microfilter in fluid communication with a reperfusion fluid line.

55. The device according to claim 44, further comprising a vacuum source coupled to the vacuum inlet.

56. A device for perfusing collected blood, Upper chamber and Lower chamber and An impermeable partition between the upper chamber and the lower chamber, One or more partition valves configured to penetrate the impermeable partition and form an opening, A coarse filter in fluid communication with the upper chamber, A vacuum inlet, which enters the upper chamber and is configured to be coupled to a vacuum source, The vacuum release valve inside the upper chamber, The suction port that enters the upper chamber, A suction valve between the suction inlet and the suction line extending from the suction inlet, A reperfusion outlet is located inside the lower chamber and is configured to be in fluid communication with the reperfusion fluid line by a reperfusion valve, A pressure regulating opening entering the lower chamber is configured to maintain the pressure inside the lower chamber above the pressure inside the upper chamber and above the pressure required for blood bubble formation, The system comprises a reperfusion fluid line and a fine filter in fluid communication, A device in which one or more partition valves are configured to open when the vacuum release valve opens to allow blood to flow from the upper chamber into the lower chamber.

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