Distal aspiration catheter and method

Abstract

The distal aspiration catheter includes a catheter body having a central lumen, at least one distal opening, and a distal tip disposed distal to the at least one distal opening. A suction source is configured to be attached to the proximal end / luer hub of the central lumen. When the suction source is activated, a static suction force is applied to partially capture clots / emboli lodged in a blood vessel within the at least one distal opening of the catheter body. The suction source may apply a periodic suction force via a forward pressure flow to induce clot fatigue on the partially captured clot. The fatigued clot can be collected within the distal tip of the catheter, allowing for complete removal of the clot with a single pass through the distal aspiration catheter.

Description

Related Applications

[0001] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 113,757, entitled "Distal Aspiration Catheter And Methods," filed on August 21, 2020, and U.S. Provisional Patent Application No. 63 / 086,200, entitled "Aspiration Thrombectomy Devices And Methods," filed on October 1, 2020, the entire contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION

[0002] Many diseases are caused by the presence of unwanted substances, particularly blood clots or thrombi, within blood vessels and heart cavities. Blood clots within blood vessels can be formed from blood cells, collagen, cholesterol, plaque, lipids, calcified plaque, air bubbles, arterial tissue, aggregates of proteins (e.g., fibrin), and / or various other debris or combinations thereof. A blood clot, for example, can occlude a narrowed portion of a blood vessel supplying a major organ, thereby preventing oxygen-rich blood from flowing to the surrounding tissue and resulting in local cell death or a microinfarct. A microinfarct in the brain is typically an ischemic stroke that can cause unconsciousness, speech disorders, paralysis, visual disturbances, balance disorders, and can lead to death. In the heart, a blood clot can cause a myocardial infarction or heart attack. Since leaving a blood clot untreated poses a potentially life-threatening risk, rapid medical intervention is required when there is a blood clot within a blood vessel.

[0003] Blood clots can typically be treated or removed using biological interventions, surgical interventions, or a combination of the two. Biological treatment methods include delivering an agent directly to the blood clot via a catheter to dissolve the blood clot or at least stabilize it until the body can expel the blood clot. However, a drawback of treating blood clots with biological agents is that most of the body is affected by the agent and there is a risk of life-threatening hemorrhagic complications.

[0004] Alternatively, or in addition to, mechanical means can be used to remove blood clots from a patient's blood vessels. Mechanical treatments typically involve aspirating, crushing, and compressing the blood clot within the vessel, and ultimately removing the clot by invasive surgery or by non-invasive means, such as using a suction catheter connected to a suction source (e.g., a pump or syringe). The obvious advantage of invasive or non-invasive mechanical treatments is that, unlike biological agents, they act directly on the blood clot to resolve the vascular occlusion without affecting healthy parts of the body.

[0005] Mechanical, non-invasive clot removal treatments generally relate to thrombectomy, particularly in the treatment of deep vein thrombosis (DVT) or peripheral and venous thrombectomy such as intracranial distal aspiration.

[0006] Vascular aspiration embolization, a treatment for acute ischemic stroke, involves aspiration, which draws the clot into a catheter, and has been proven to be as effective as mechanical thrombectomy using a stent retriever, which deploys a self-expanding stent-like capture device to capture and retrieve the thrombus. Vacuum embolization has gained support from the majority of neurologists due to its ease of technique and cost-effectiveness.

[0007] In aspiration embolization, a distal suction catheter (DAC) is used to remove a clot or embolus from a blood vessel. In the first step of this technique, the distal end of the catheter is positioned near the clot, and then negative pressure is applied through the lumen within the catheter using a pump or a high-volume syringe. Use by Can be applied The suction force partially takes in or draws the embolus into the distal part of the DAC. In such cases, i.e., when the embolus is partially taken in, the device may need to be passed through repeatedly to reopen the blood vessel.

[0008] However, favorable clinical outcomes for patients undergoing suction embolization may depend in part on the "first-pass effect." The "first-pass effect" refers to the complete or near-complete reopening of the target vessel by completely removing the embolus in the first attempt, requiring only a single pass of the embolization device.

[0009] However, within blood vessels, thrombi can undergo a process called organization, in which a soft, gel-like red / purple coagulation mass transforms into a hard, whitish coagulation mass through cross-linking of proteins such as fibrin. Furthermore, the coagulation mass may form a hardened body over time due to the pressure of blood flow in the anterograde direction. Over time, the hardened coagulation mass may grow into a large, rigid, and firmly rooted mature thrombus that is difficult to completely capture into a conventional DAC by static suction with an attached pump or suction syringe kit. Therefore, if the thrombus / embolus is only partially captured by static suction with a conventional DAC, the likelihood of achieving a first-pass effect decreases, and it may be necessary to reinsert the conventional DAC to completely remove the thrombus / embolus.

[0010] Furthermore, during removal, firmly rooted mature thrombi / embolus may break apart, and the fragments may be carried to other parts of the blood vessel. The above risk factors when removing large, firmly rooted mature thrombi using conventional DACs reduce the possibility of the "first-pass effect" and negatively impact the patient's clinical outcome.

[0011] Furthermore, the Solumbra technique, which combines a stent retriever with a conventional DAC, is becoming a common method of mechanical thrombectomy for acute ischemic stroke. However, it has not been shown that the Solumbra technique is more effective as a first-pass thrombectomy than aspiration embolization alone.

[0012] Therefore, there is a need for an improved DAC that can at least solve the aforementioned problems with conventional DACs using static aspiration, particularly in order to remove firmly rooted mature thrombi and completely reopen blood vessels with a single pass of the DAC device, thereby improving patient clinical outcomes. [Overview of the project]

[0013] This invention relates to an aspiration catheter and a method of using it for fatigueing a blood clot so that it can be completely removed from a blood vessel. These catheter devices and methods can be particularly useful in cases of hard and / or firmly rooted blood clots that would otherwise be difficult to remove. In some cases, these embodiments and methods may lead to the reopening of the blood vessel with just one catheter pass.

[0014] In one embodiment, the aspiration catheter comprises a catheter body having a catheter tip usable for fatigue of a coagulated mass, and a coagulated mass holding cavity, coagulated mass holding chamber, or coagulated mass holding lumen into which a coagulated mass can be placed after catheter insertion. In one example, the catheter tip is located at the distal end of the catheter, and the coagulated mass holding lumen is located at least partially within the catheter tip. The coagulated mass holding lumen is connected to or communicates with a main aspiration lumen extending between the proximal and distal ends of the catheter, and at least one distal opening is located proximal to the distal end of the catheter tip, allowing a coagulated mass to be drawn into the catheter and placed within the coagulated mass holding lumen.

[0015] The catheter tip can be relatively smooth and may have a shape configured to assist in the penetration or softening of coagulated masses, such as a spiral or vortex shape. One or more distal openings can be a single opening radially offset from the center of the catheter tip, or multiple openings arranged radially around the distal portion of the catheter.

[0016] Generally, the catheter tip can first be advanced into or near the coagulation mass, and suction can be performed to guide this coagulation mass from the distal opening of the catheter into the coagulation lumen. In one example, static suction is performed towards the distal opening through the main suction lumen of the catheter to move the coagulation mass at least partially into the distal opening. Periodic suction can be performed to aid in fatigue or weakening of the coagulation mass and further movement of the coagulation mass into the main suction lumen of the catheter. Periodic suction tends to apply a small proximal force at the start of suction and a small distal force in the opposite direction at the stop, which can make it easier to move the coagulation mass at least partially into the coagulation lumen at the catheter tip. Once the coagulation mass is partially or completely taken up by the catheter, both the catheter and the coagulation mass can be removed from the patient. [Brief explanation of the drawing]

[0017] Possible embodiments of the present invention, both above and other, aspects, features, and advantages will become apparent from the following description of embodiments of the present invention. Refer to the accompanying drawings.

[0018] [Figure 1] This is a perspective view of aspiration embolization, a conventional DAC procedure used to treat acute ischemic stroke, showing the state in which suction force is applied to partially take up the coagulation mass.

[0019] [Figure 2] A perspective view of the DAC in one embodiment of the present invention.

[0020] [Figure 3] A side elevation view of the distal portion of an embodiment of the DAC of the present invention.

[0021] [Figure 4] End view of the distal portion of an embodiment of the DAC of the present invention.

[0022] [Figure 5A]Figure showing the steps of a method of using an embodiment of a DAC for performing embolization

[0023] [Figure 5B] Figure showing the steps of a method of using an embodiment of a DAC for performing embolization

[0024] [Figure 5C] Figure showing the steps of a method of using an embodiment of a DAC for performing embolization

[0025] [Figure 6] Perspective view of a DAC according to an embodiment of the present invention

[0026] [Figure 7] Perspective view of the distal portion of an embodiment of a DAC of the present invention

[0027] [Figure 8] Perspective view of a DAC according to an embodiment of the present invention

[0028] [Figure 9] Perspective view of a DAC according to an embodiment of the present invention

[0029] [Figure 10] Figure showing the steps of a method of using an embodiment of a DAC for performing embolization

[0030] [Figure 11] Figure showing the steps of a method of using an embodiment of a DAC for performing embolization

[0031] [Figure 12] Perspective view of a DAC according to an embodiment of the present invention

[0032] [Figure 13] Perspective view of a DAC according to an embodiment of the present invention Detailed Description

[0033] Detailed embodiments of the present invention will be described below with reference to the accompanying drawings. However, the present invention may be realized in many different forms and should not be construed as being limited to the embodiments described herein. These embodiments are provided rather so as to make this disclosure sufficient and complete and so as to convey the scope of the invention to those skilled in the art. The terms used in the detailed description of the embodiments shown in the accompanying drawings are not intended to limit the invention. In the drawings, similar reference numerals refer to similar elements. Although various embodiments are described, the features of each embodiment can be used interchangeably with those of the other embodiments described. That is, any feature of each embodiment can be combined with one another, and embodiments should not be strictly construed as including only the illustrated or described features.

[0034] The terms coagulation mass, thrombus, and embolus are interchangeable within this specification. These terms generally refer to a mass or bound group of blood cells, collagen, cholesterol, plaque, lipids, calcified plaque, bubbles, arterial tissue, protein aggregates (e.g., fibrin), and / or various other fragments or combinations thereof.

[0035] As mentioned above, existing suction catheterization methods that use only static suction force may not be effective in removing large, firmly rooted coagulations from inside blood vessels, in particular, because a single pass of the suction catheter may not completely draw the coagulation into the catheter. For example, Figure 1 shows a conventional distal access catheter (DAC) 20 used to remove a large coagulation 10 from inside a blood vessel. The DAC 20 is typically thought to have an inner diameter cross-section in the range of 1.3 (4F) mm to 4 (12F) mm. In this example, the coagulation 10 is blocking the middle cerebral artery, causing a large vascular occlusion and acute ischemic stroke. During the removal procedure, the distal end of the DAC 20 is positioned near the coagulation 10, and negative pressure is applied at the proximal end of the lumen by an attached pump or suction syringe, partially drawing the coagulation into the distal lumen of the DAC 20 or aspirating it.

[0036] If the coagulation mass 10 is firmly rooted and / or larger than the diameter of the DAC 20, applying negative pressure alone may not be effective in completely removing the coagulation mass 10 and reopening the vessel. In other words, passing the device 20 through once may not completely remove the coagulation mass 10. Using a larger diameter DAC and / or applying stronger negative pressure may be possible, but large-section DACs are difficult to insert to achieve distal intracranial blood circulation and may damage the vascular lumen, causing dissection or vasospasm.

[0037] One aspect of the present invention seeks to address the shortcomings of existing devices in removing coagulated tissue by passing it through the DAC only once during a procedure. Some of the embodiments described herein relate to a DAC (more generally referred to as a catheter) which may include specific structural features used in connection with periodic aspiration aimed at fatigueing the coagulated tissue, moving the coagulated tissue into the catheter, and / or reliably capturing the coagulated tissue within the DAC for safe retrieval from the patient.

[0038] The term "coagulation fatigue" is generally defined as the process of partially or completely disintegrating a coagulation by applying mechanical stress to it to alter or reduce its stiffness, dimensions, and / or adhesiveness. Performing a procedure to fatigue a coagulation can make aspiration of the coagulation into a catheter and retrieval from the patient particularly easier.

[0039] The DAC of the present invention can be used in all types of blood vessels for the removal of coagulation clots and the treatment of vascular occlusion. For example, the DAC of the present invention can be used for the treatment of vascular occlusion such as acute ischemic stroke, peripheral arterial thrombosis, pulmonary embolism (e.g., pulmonary artery), deep vein thrombosis, systemic venous circulation (e.g., jugular vein, sigmoid sinus, transverse sinus, superior and inferior sagittal sinuses, superior vena cava, pelvic vein, femoral vein, or subclavian vein), or arterial circulation (e.g., aorta or its major or intermediate branches).

[0040] In some embodiments, the DAC includes a distal tip extending distal to the distal opening of its suction lumen. The distal tip is configured to assist in the physical guidance of a solidified mass into one or more distal openings of the suction lumen and / or to induce solidified mass fatigue by physical contact. For example, the shape of the distal tip may be a relatively smooth cone, a flattened cone (e.g., a roughly oval cross-section), a cone with a recess extending axially toward the distal opening of the suction lumen, a triangular shape, a relatively rectangular shape, a helical shape, a conical helical shape, a cone with multiple axial channels extending axially toward one or more distal openings of the suction lumen, a cylindrical shape, or a combination or similar variation thereof.

[0041] A DAC may include one or more distal openings in its suction lumen. One or more distal openings may be located proximal to the distal tip (e.g., approximately 5 mm to 25 mm from the most distal end of the distal tip). In the case of a single distal opening, the distal opening may be angled distally, laterally, or both distally and laterally (e.g., approximately 45 degrees with respect to the axis of the DAC). In one example, the single distal opening may be positioned off-axis or asymmetrically. In other words, the distal opening may be positioned closer to one side of the DAC, in which case the distal tip may optionally be positioned closer to the other side of the DAC.

[0042] In another example, the suction lumen of a DAC can include multiple distal openings. For example, it may include two, three, four, five, six, seven, eight, or more openings. All of these openings can be positioned at different locations circumferentially but the same location longitudinally, or at two or more different locations circumferentially but longitudinally (i.e., some openings are more proximal than others).

[0043] One or more openings may have various different shapes, such as oval, square, or rectangular. Furthermore, these openings can be surrounded by a uniform portion of the outer DAC wall. Alternatively, they can be located within recesses or channels in the outer DAC wall, configured to assist in guiding solidified mass portions into one or more of these distal openings.

[0044] In any embodiment of this specification, the DAC may include a valley or longitudinal recess extending along at least a portion of the length of the distal tip. This valley or longitudinal recess may also include one or more openings opening into an internal cavity or suction lumen. These openings may facilitate the abutment of solidified masses against the tip and their incorporation into the distal opening. If there are multiple openings, they may be arranged longitudinally along the length of the longitudinal recess. The diameters of these openings may all be the same or different; for example, the diameter may increase towards the proximal side to facilitate the incorporation of solidified masses into the distal opening. Alternatively, there may be no valley or longitudinal recess, and instead, multiple openings may be arranged along the surface of the distal tip, alongside, or at least near, the distal opening leading to the suction lumen.

[0045] The suction lumen generally comprises a flow path between the distal end of the DAC, including a distal opening, and the proximal end of the DAC (e.g., a port on the catheter hub of the DAC). A suction source, such as a syringe or a motor-driven suction device, can be connected to or communicated with the proximal end of the suction lumen, thereby allowing selective suction to be applied to the suction lumen.

[0046] Suction sources, particularly motor-driven suction devices, can be configured to apply periodic suction to the suction lumen during a procedure. Periodic suction generally involves increasing or decreasing the suction or sweep level relatively quickly and continuously. For example, the suction level can be changed at the start and stop, or alternatively, it can be changed between a weak level and a strong level. In another example, the suction period can be between 0.5 and 3 seconds (e.g., 0.5, 1, 1.5, 2, 2.5, or 3, and combinations thereof).

[0047] Furthermore, with respect to periodic suction, the DAC may include one or more features that assist in containing or capturing coagulation masses within the DAC when used with periodic suction. For example, the distal portion of the DAC may be partially or completely hollow, and the distal portion may include multiple surfaces that facilitate the intake of coagulation masses into the suction lumen when suction is increased and facilitate the release of coagulation masses into the internal lumen or internal cavity of the distal portion when suction is decreased or stopped. Thus, coagulation masses may be "trapped" in the internal cavity of the distal portion of the DAC, thereby preventing the coagulation masses from flowing out or falling out when the DAC is withdrawn from the patient.

[0048] A specific embodiment of the DAC100 is shown in Figures 2 to 5C, and may include a distal portion 140 of the DAC100 with a distal tip 102, and a distal opening 120 of the suction lumen 101 of the DAC100. As will be described later, the distal tip 102 and the distal opening 120 are positioned on both sides of the longitudinal axis of the DAC100 so that the distal tip 102 can be used to selectively fatigue the solidified mass and assist in guiding the solidified mass into the distal opening 120. Furthermore, the distal tip 102 may include a lumen or internal cavity 110 within the DAC100 that communicates with the suction lumen 101 and can partially or completely draw the solidified mass inside, especially when using periodic suction. The internal cavity 110 may be referred to as an internal solidified mass holding cavity.

[0049] The distal tip 102 generally constitutes the most distal structure at the end of the distal portion 140 of the DAC 100. In this embodiment, the distal tip 102 is offset from the longitudinal axis of the DAC 100 and positioned towards one side of the DAC 100. This offset position may allow the distal tip 102 to smoothly advance around or to the side of the solidified mass, making it easier for the solidified mass to be positioned facing the distal opening 120. The rounded distal tip 102A and the sloping transition region 102B adjacent to the distal opening 120 may further facilitate the positioning of the solidified mass facing the distal opening 120 before or during suction via the suction lumen 101.

[0050] Alternatively, depending on the shape of the distal tip 102, the distal tip 102 may be positioned roughly radially symmetrically (i.e., in the center of the device) around the longitudinal axis of the DAC 100, or partially around it.

[0051] The distal tip 102 of this embodiment has a generally conical or cylindrical shape, terminating at a rounded closed end 102A. Alternatively, the distal tip may have a flattened conical shape (e.g., a generally oval cross-section), a conical shape with recesses or valleys in the outer surface extending axially toward the distal opening 120 of the suction lumen 101, a triangular shape, a relatively rectangular shape, a helical shape, a conical helical shape, a cylindrical shape, or a combination or similar variation thereof. The length of the distal tip may be in the range of about 1 mm to 5 mm.

[0052] In some embodiments, the distal portion 140 may include an internal lumen / chamber / cavity 110. The internal cavity 110 is at least partially located distal to the distal opening 120 and communicates with the suction lumen 101, thereby allowing the internal cavity 110 to capture solidified masses at least partially, particularly when periodic suction is used as described later herein. In this exemplary embodiment, as shown by the dotted line in Figures 5A-5C, the internal cavity 110 is located within the distal tip 102, at least partially hollow, and forms a continuous flow path with the suction lumen 101. The internal cavity 110 may extend along the entire length of the distal tip 102 or along only a portion of its length. Although the internal cavity is illustrated as a relatively uniform cylindrical or conical shape, other shapes such as an oval cross-sectional shape are also possible. Furthermore, the inner surface of the internal cavity 110 may have protrusions, annular bodies, wavy bodies, hooks, pins, or similar features that help to anchor solidified masses in place.

[0053] The distal opening 120 of the suction lumen 101 can be positioned near the proximal end of the distal tip 102. In this embodiment, the distal opening 120 is positioned towards one side of the DAC 100, offset from the longitudinal axis of the DAC 100, and on the opposite side from the distal tip 102. Alternatively, depending on the position and shape of the distal tip 102, the distal opening 120 may be positioned approximately radially symmetrically around the longitudinal axis of the DAC 100 (i.e., around part or all of the distal tip in the center of the device).

[0054] The distal opening 120 can be made roughly semicircular to maximize its dimensions, but other shapes such as circular or oval, as well as smaller or larger dimensions, are also possible.

[0055] Furthermore, the distal opening 120 may be configured with its opening at various angles with respect to the longitudinal axis of the DAC 100. In this embodiment, the distal opening 120 is bias-cut at approximately 45 degrees with respect to the longitudinal axis of the DAC 100 or constitutes a plane 122 at this angle (best seen in Figure 3). The transition region 102B shown in Figure 2 may constitute a plane at an angle similar to, or larger or smaller than, the distal opening 120. Other angles of the distal opening 120 are also possible, such as 90 degrees (i.e., a right angle), 315 degrees (the opposite angle to the angle in Figure 2), 15 degrees, 25 degrees, 75 degrees, or any angle within 10 percent of these values.

[0056] If the distal opening 120 in Figure 3 is 45 degrees, or if the opening is at a similar angle that increases towards the proximal side, the solidified mass may slide in more easily by contacting it with the distal opening 120, allowing for better opposing positioning of the solidified mass. If the angle of inclination is such that it slopes inward toward the center of the cross-section of the DAC 100 towards the proximal side, such as 315 degrees, the solidified mass may be secured on both sides by extending at least partially parallel to and opposite the distal tip 102.

[0057] As shown in Figure 12, in some embodiments, the DAC 100 may include a valley or longitudinal recess extending along at least a portion of the length of the distal tip 102. This valley or longitudinal recess may also include one or more openings 121 opening into an internal cavity 110 or suction lumen 101. These openings 121 may facilitate the drawing of solidified material into the distal opening 120 by bringing it into contact with the distal tip 102. If there are multiple openings 121, they may be arranged longitudinally along the length of the longitudinal recess. The diameters of these openings 121 may all be the same or different; for example, the diameter may increase towards the proximal side to facilitate the drawing of solidified material into the distal opening 120. Alternatively, the valley or longitudinal recess may not be included, and instead, the multiple openings 121 may be arranged along the surface of the distal tip 102, alongside, or at least near, the distal opening 120 leading to the suction lumen 101.

[0058] The DAC100 can be manufactured according to known catheter manufacturing methods, having at least an outer tubular wall 160 that forms a suction lumen 101 extending between the distal opening 120 and the proximal end of the DAC100 (e.g., a port on the catheter hub of the DAC100, not shown). It may be desirable that the DAC100 be more flexible towards its distal end than towards its proximal end. This can be achieved by constructing different parts of the catheter wall 160 from different materials. For example, the proximal wall portion 160B may be made of the distal wall portion 160A It may include a material with higher rigidity, and the distal tip 102 and / or the rounded distal end 102A may be made of a more flexible material.

[0059] One method for achieving such different rigidities is to fuse a tube made of a first material with a first hardness for creating the proximal wall portion 160B to another tube made of a second material for creating the distal wall portion 160A, as shown in Figure 7. By making the diameter of the proximal portion 160 and the distal portion 140 the same or identical, the proximal wall portion 160B can be fused to the distal wall portion 160A at surface 150. Distal wall 160A can be fabricated from any material that is flexible and resistant to twisting during entry without compromising the durability of the DAC100, such as PeBax or other thermoplastic resins. proximal wall 160B may contain a braided polymer or reinforcing polymer, such as PTFE, to increase the rigidity of the proximal portion 160, thereby increasing rigidity and allowing a handle (not shown) to be well attached to the proximal wall portion 160B.

[0060] Optionally, any DAC described herein may include radiopaque markers. These markers can be positioned at or near the distal end of the DAC, around or near the distal opening, and at one or more locations proximal to the distal opening. Returning to the embodiment of DAC 100, Figure 6 shows a first radiopaque marker 104 positioned at or within the distal end portion 102A of the distal tip 102. Alternatively, or in addition to this, markers 104 can be positioned at other locations along the distal tip 102.

[0061] The distal opening 120 of the DAC100 may include a radiopaque marker 124 positioned on or along the edge of the distal opening 120, as shown in Figure 6. This may allow the physician to confirm the angle of the opening and its relative distance from the radiopaque marker 104. Alternatively, the marker 124 may be positioned or embedded in the distal wall 160A near the distal or proximal end of the distal opening 120. The radiopaque marker bands 104, 124 may be composed of a radiopaque material, platinum, tantalum, or a similar metal.

[0062] Each DAC described herein can be used with static suction (i.e., constant negative suction pressure), periodic suction force (i.e., alternating between high suction force and low suction force / no suction force), or a combination thereof, to completely remove the coagulation mass 10 and reopen the blood vessel blocked by the coagulation mass.

[0063] In the case of periodic suction, a phenomenon commonly known as the "water hammer effect" can occur. Typically, the water hammer effect refers to a sudden pressure surge or high-pressure shock wave in the liquid conduits of a piping system when a moving fluid is forced to change direction or stop abruptly. In the present invention, such a pressure surge or shock wave can cause the fluid within the suction lumen to move in the opposite direction to the suction for a very short time. In other words, during suction, the fluid moves proximal to the suction source within the suction lumen, but when the suction suddenly stops or decreases, the pressure shock wave can push the solidified mass (and possibly a small amount of fluid) distally.

[0064] The consequences of the water hammer effect are best illustrated in the embodiments of the DAC100 shown in Figures 5A-5C. In Figure 5A, suction is initiated and the coagulated mass 10 is moved proximal until it is at least partially inside the distal opening 120. If the suction is suddenly stopped or reduced, a pressure shock wave is generated as shown by the arrow in Figure 5C. This pushes the coagulated mass into the internal cavity 110 of the distal tip 102. The suction cycle required to achieve this water hammer effect may be a single cycle, or it may be performed multiple times (e.g., two, three, four, five, six, seven, eight, or more times) to position the coagulated mass 10 in the desired location within the internal cavity 110. Positioning the coagulated mass 10 within the internal cavity 110 in this way may more reliably capture the coagulated mass 10, thus potentially preventing the coagulated mass 10 from slipping out of the DAC100 when it is removed from the patient.

[0065] It should be noted that, as an alternative to this water hammer pressure wave, the objective of moving the solidified mass into the internal cavity 110 may also be achieved by first applying suction in the proximal direction for a certain period of time, followed by applying distal pressure in the distal direction for a short time (backflow within the suction lumen 101).

[0066] For completeness, the method using the DAC100 shown in Figures 2 to 7 is further described below. However, it should be understood that this method can be implemented in any of the embodiments and / or variations described herein.

[0067] A guidewire and / or transport sheath (not shown in the drawing of DAC100) may first be deployed in the patient's body so that the distal end 102 of DAC100 is positioned near the coagulation mass 10. For example, DAC100 may be inserted into the target vessel (e.g., through a suction lumen 101 or another guidewire lumen) while covered by the guidewire and advanced toward the coagulation mass 10. Alternatively, DAC100 may be advanced within a sheath positioned so that its distal end is positioned near the coagulation mass 10. Radiopaque marker bands 104, 124 of DAC100 can be used to confirm that DAC100 is properly positioned toward the coagulation mass 10.

[0068] As shown in Figure 5A, the DAC 100 is advanced further distally so that the distal tip 102 is positioned laterally to the solidified mass 10. Alternatively, or in addition to this, depending on the shape of the distal tip 102, the distal tip 102 may be positioned inside or through the solidified mass 10. Optionally, the distal tip 102 may be moved (proximal, distal, or lateral) to physically move the solidified mass and induce solidified mass fatigue.

[0069] When the solidified mass 10 is located near or in contact with the distal opening 120, a suction source connected to the proximal end of the suction lumen 101 is activated so that the solidified mass 10 is at least partially taken into the suction lumen 101 of the DAC 100 (as shown in Figure 5B).

[0070] This can be achieved by static or periodic suction. In particular, if the coagulated mass is of a size or composition that makes it difficult to pass through the distal opening 120, applying periodic suction at this time may accelerate the fatigue of the coagulated mass 10. Especially, the water hammer pressure wave generated from periodic suction can easily generate a dynamic normal force on the coagulated mass in the range of 0-1 N that induces coagulated mass fatigue. Generally, a force greater than 0.5 N is considered appropriate in many cases. It is important to note that pressures of such values ​​are not static forces, but rather instantaneous, in the form of a dynamic / abrupt gradient characterized by a water hammer pressure wave. Therefore, it may be desirable to perform periodic suction for an initial period of time to generate a pressure wave that fatigues the coagulated mass 10, and then apply static suction for a certain period of time to draw at least a portion of the coagulated mass 10 into the suction lumen 101.

[0071] After the coagulation mass 10 has been taken into the suction lumen 101, at least partially (Figure 5B), periodic suction may be performed for an additional period of time. As shown in Figure 5C, the water hammer pressure wave generated by periodic suction may push part or all of the coagulation mass 10 distally forward, into the internal cavity 110 of the distal tip 102. This positioning of the coagulation mass 10 within the internal cavity 110 makes it easier to hold or secure the coagulation mass in place, which can be particularly beneficial when the DAC 100 is withdrawn proximal to the patient's blood vessel. Depending on the circumstances, if part of the coagulation mass remains outside the DAC 100 or if distal suction occurs due to the proximal movement of the DAC 100, this withdrawal motion may generate force on the coagulation mass 10.

[0072] After the removal of the DAC100, a contrast agent may be injected to confirm whether the blood vessel has been reopened.

[0073] As described above, the tip of the DAC can have various different shapes and may have multiple distal openings leading to the suction lumen of the DAC. Figures 8 and 9 show such a DAC 200. The DAC 200 is generally similar to the DAC 100 described above in terms of structure and function, but the distal portion 204 of the DAC 200 may include a distal tip 202 that includes a spiral shape. Furthermore, it may include multiple distal openings 220 leading to the suction lumen 212 of the catheter body 206.

[0074] The distal tip 202 is generally spiral or helical in shape and is located at the most distal end of the DAC200. In other words, the distal tip 202 is generally conical with a spiral groove or thread that spirals along its length. In one example, the distal tip can be between approximately 2 mm and approximately 10 mm in length. The distal tip 202 is preferably made of a somewhat soft material to reduce or prevent damage to the patient's blood vessels.

[0075] The distal tip 202 is connected to an intermediate cone 208 that forms a relatively uniform connecting interface between the small-diameter distal tip 202 and the large-diameter catheter body 206. Similar to the DAC 100 described above, the intermediate cone 208 may have an internal cavity 210 inside it, distal to the distal opening 220, in which a coagulation mass 10 can be placed (this internal cavity 210 is shown by a dotted line in the figure). The length of the cone 208 can be between approximately 3 mm and approximately 15 mm.

[0076] The internal cavity 210 can extend along the entire length of the distal tip 202, or along only a portion of its length. Although the internal cavity is illustrated as a relatively uniform cylindrical or conical shape, other shapes such as an oval cross-section are also possible. Furthermore, the inner surface of the internal cavity 210 may have protrusions or similar features that help to anchor annular, corrugated, hook, pin, or solidified mass in place.

[0077] In this embodiment, the distal tip 202 is configured not to rotate relative to the intermediate cone 208 and the catheter body 206. In some cases, it may be useful to rotate the entire DAC 200 at least partially to facilitate the anchoring and movement of the coagulation mass 10 toward the distal opening 220. However, the DAC 200 may be configured such that the distal tip 202 rotates relative to the intermediate cone 208 and / or the catheter body 206. In such an embodiment, the shaft may be connected to the distal tip 202 and extend to the proximal end of the catheter body 206, at which proximal end the shaft can be manually rotatable or connected to a motor-driven rotation mechanism.

[0078] Multiple distal openings 220 open into the suction lumen 212 of the catheter body 206, allowing at least partial aspiration of the coagulated mass 10 through them. In this embodiment, three distal openings 220 are included, but two, three, four, five, six, seven, eight, or more distal openings 220 are also possible. In this embodiment, all distal openings 220 are located at the same longitudinal position in the distal portion 204 of the catheter body 206, but it is intended that one or more of these distal openings 220 may be located more distally or proximal to the other openings in the longitudinal direction.

[0079] The distal opening 220 of the DAC200 in this embodiment is generally rectangular in shape, but other shapes are also possible. For example, circular, oval, square, and similar shapes are possible. In order to capture relatively large solidified masses 10, it is desirable that each distal opening be relatively large in size. One way to achieve this with multiple distal openings 220 is to configure the axial length of each distal opening 220 of the DAC200 to be longer than the width along the circumference of the DAC200. This allows more openings 220 to be provided around the circumference of the DAC200 while still being able to accept or capture relatively large solidified masses.

[0080] In addition to such antipodal shapes, other shapes and design features may also be included as part of the distal opening 220 to assist the movement of the solidified mass 10 into the suction lumen 212 in a desired manner. For example, the distal opening 220 in this embodiment forms a recessed region or groove with a lowered surface 220A. The lowered surface 220A can be angled radially inward as it extends distally toward the opening leading to the suction lumen 212 at the distal end of the recessed region. In this respect, a lowered surface 220A that becomes lower distally may facilitate the distal guidance of the solidified mass 10 into the suction lumen 212 so that the solidified mass 10 moves more effectively into the internal cavity 210 of the intermediate cone 208 when periodic suction is performed and a water hammer pressure wave is generated. Alternatively, multiple distal openings 220 may open directly into the suction lumen 212.

[0081] As shown in Figure 13, in some embodiments, the recessed region or groove having a lowered surface 220A may also include one or more openings 221 opening into the internal cavity 210 or suction lumen 212. These openings 221 may facilitate the drawing of solidified mass into the lowered surface 220A and further into the suction lumen 212. If there are multiple openings 221, they may be arranged longitudinally along the length of the lowered surface 220A. These openings 221 The diameters of the openings may all be the same or different. For example, the diameter may increase towards the proximal side to facilitate drawing the solidified mass into the suction lumen 212. Alternatively, multiple openings 221 may be arranged along the surface of the cone portion 208, alongside, or at least near, the distal opening 220 leading to the suction lumen 212.

[0082] The figure shows multiple distal openings 220 on the cylindrical side surface of the catheter body 206. However, one or more openings may be located on the distal surface of a cone, such as the intermediate cone portion 208.

[0083] As in the embodiments described above, radiopaque markers can be included near or within the distal tip 202, or near a plurality of distal openings 220.

[0084] For completeness, the method of using the DAC200 is further described below and shown in Figures 10 and 11. However, it should be understood that this method can be implemented in any of the embodiments and / or variations described herein.

[0085] A guidewire and / or transport sheath (not shown in the DAC200 drawing) may first be deployed into the patient's blood vessel 30 so that the distal end 202 of the DAC200 is positioned near the coagulation mass 10. For example, the DAC200 may be inserted into the target blood vessel 30 with the guidewire over it (e.g., through the suction lumen 201 or another guidewire lumen of the DAC200) and advanced toward the coagulation mass 10. Alternatively, the DAC200 may be advanced within a sheath positioned so that its distal end is positioned near the coagulation mass 10. A radiopaque marker band (such as that shown in the above embodiment) can be used to confirm that the DAC200 is properly positioned toward the coagulation mass 10.

[0086] As shown in Figure 10, the DAC200 is advanced further distally so that the distal tip 202 is at least partially positioned within the solidified mass 10. Optionally, the DAC200 may be rotated, or the distal tip 202 may be rotated via the shaft (if any) within the DAC200 to at least partially rotate and screw the distal tip 202 into the solidified mass 10.

[0087] A suction source connected to the proximal end of the suction lumen 212 is activated so that the coagulated mass 10 is further moved toward the distal opening 220 and at least partially taken into the suction lumen 212 of the DAC 200 (as shown in Figure 11).

[0088] This can be achieved by static or periodic suction. In particular, if the coagulation mass is of a size or composition that makes it difficult to pass through the distal opening 220, applying periodic suction at this time may accelerate further fatigue of the coagulation mass 10. Especially, the water hammer pressure wave generated from periodic suction can easily generate forces on the coagulation mass 10 that induce coagulation mass fatigue. Therefore, it may be desirable to perform periodic suction for an initial period of time to generate pressure waves that fatigue the coagulation mass 10, and then apply static suction for a certain period of time to draw at least a portion of the coagulation mass 10 into the suction lumen 212.

[0089] After the coagulation mass 10 has been taken into the suction lumen 212, at least partially (Figure 11), periodic suction may be performed for an additional period of time. The water hammer pressure wave generated by periodic suction may push part or all of the coagulation mass 10 distally forward, into the internal cavity 210 of the intermediate cone 208. This positioning of the coagulation mass 10 within the internal cavity 210 makes it easier to hold or secure the coagulation mass in place, which can be particularly beneficial when the DAC 200 is withdrawn proximal to the patient's blood vessel. Depending on the circumstances, if part of the coagulation mass remains outside the DAC 200 or if distal suction occurs due to the proximal movement of the DAC 200, this withdrawal motion may generate force on the coagulation mass 10.

[0090] After the removal of the DAC200, contrast agent may be injected to confirm whether the blood vessel has been reopened.

[0091] While specific embodiments and features of these embodiments have been disclosed, it should be understood that any of the features described herein can be used in any combination. Therefore, although specific embodiments have been described as examples, the features described herein are intended to be mixed and combined in any manner.

[0092] While the present invention has been described in relation to specific embodiments and uses, those skilled in the art can, based on this teaching, generate additional embodiments and variations without deviating from or exceeding the spirit of the invention as described in the claims. Therefore, these drawings and the specification are provided as examples to facilitate understanding of the invention and should not be construed as limiting its scope.

Claims

1. A catheter for removing coagulation masses, The catheter body comprises a catheter body including a first lumen between the proximal portion of the catheter body and the distal portion of the catheter body, The catheter body is located at the distal part of the catheter body and has a closed distal tip having a hollow cavity that is in fluid communication with the first lumen, The catheter body has an opening in the first lumen and a distal opening located near the proximal end of the distal tip, A coagulation removal catheter, wherein the distal opening has a recessed region with a downward-sloping surface that is radially inward as it extends distally, so as to guide the coagulation mass into the hollow cavity.

2. The coagulation removal catheter according to claim 1, further comprising a suction source connected to the first lumen and configured to perform periodic suction, which alternately provides a first suction force and a second suction force different from the first suction force.

3. The coagulation block removal catheter according to claim 1, wherein the distal opening and the distal tip are located on opposite sides of the longitudinal axis of the catheter body.

4. The coagulation removal catheter according to claim 1, wherein the distal opening is positioned at an angle of 15 to 315 degrees with respect to the longitudinal axis of the catheter body.

5. The coagulation removal catheter according to claim 1, wherein the distal opening has a semicircular, rectangular, square, or oval shape.

6. The coagulation block removal catheter according to claim 1, wherein the distal tip has a conical, cylindrical, triangular, rectangular, spiral, or vortex shape.

7. The coagulation block removal catheter according to claim 1, wherein the distal opening comprises a plurality of distal openings.

8. A catheter for removing coagulated masses, The catheter body comprises a catheter body including a first lumen between the proximal portion of the catheter body and the distal portion of the catheter body, The catheter body is located at the distal part of the catheter body and has a closed distal tip having a hollow cavity that is in fluid communication with the first lumen, The catheter body has an opening in the first lumen and a distal opening located near the proximal end of the distal tip, The distal opening comprises a plurality of distal openings, A coagulation removal catheter in which the plurality of distal openings are arranged within the flow path on the outer surface of the catheter body.

9. The coagulation clot removal catheter according to claim 1, further comprising an X-ray opaque marker positioned along the edge of the distal opening.

10. The coagulation block removal catheter according to claim 7, wherein the plurality of distal openings are arranged at the same position with respect to the longitudinal direction or at positions different from each other with respect to the longitudinal direction.

11. The coagulation block removal catheter according to claim 7, wherein the plurality of distal openings are located between 0 and 90 degrees with respect to the longitudinal axis of the catheter body.

12. The coagulation block removal catheter according to claim 1, wherein the height of the distal opening increases towards the proximal side.

13. The coagulation block removal catheter according to claim 1, further comprising a recessed region formed in the catheter body and shifted proximal to the distal tip.

14. The coagulation block removal catheter according to claim 13, wherein the recessed region comprises one or more openings that open into the first lumen, and the one or more openings are different from the distal opening.

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