Catheter systems enabling improved aspiration from cerebral arteries

Abstract

To provide catheter systems and methods for accessing the brain during endovascular / neurointervention procedures in treatment of ischemic stroke.SOLUTION: Catheter systems are described that enable quicker and improved access to cerebral vessels as well as improved processes of accessing and aspirating blood clots from the cerebral vessels of a patient with acute ischemic stroke due to medium or large vessel occlusion. For gaining access to cervical and cerebral arteries in the brain of a patient and aspirating an intracranial clot from the cerebral arteries, a catheter comprises a catheter body having a distal tip region and a proximal region. The catheter body has a length longer than 120 cm and an outside diameter (OD) longer than 6F and shorter than 10F; and the distal tip region has a length of 12 to 30 cm.SELECTED DRAWING: Figure 2A

Description

[Technical Field]

[0001] The present invention describes a catheter system and method for accessing the brain during endovascular / neurointerventional procedures in the treatment of ischemic stroke. More specifically, a catheter system is described that allows for rapid and improved access to the cerebral vasculature and an improved process for accessing and aspirating blood clots from the cerebral vasculature in patients with acute ischemic stroke due to occlusion of medium or large blood vessels. [Background technology]

[0002] The human body is an extensive network of blood vessels, including the venous and arterial systems, that circulate blood throughout the body. The occurrence and / or development of restriction to flow within the circulatory system can result in serious pathologies, the most serious of which are myocardial infarction and ischemic stroke. Treatment for these two conditions (and others related to the circulatory system) continues to evolve, with many new techniques and devices being utilized to deliver various treatments.

[0003] As is known, ischemic strokes caused by a blood clot blocking within the brain can be treated by advancing a catheter system to the affected area where various procedures can be initiated to treat the problem. Known procedures include deploying catheters of various designs alone and / or in combination with other catheters, stents, and clot retrieval devices to access and remove the blood clot.

[0004] By way of background, when a patient experiences a severe ischemic stroke event, those portions of the brain distal to the blockage that experience a dramatic reduction in blood supply will affect the function of large areas of neurons. This reduction in blood supply can cause the patient to experience symptoms and can lead to the death of areas of the brain and / or put areas of the brain at risk of death if not promptly treated. Depending on the location and size of the blockage, the patient will experience a wide range of symptoms, the severity of which can ultimately determine whether a physician will intervene.

[0005] A time delay in the effectiveness of treatment typically results in the death of more neurons. Table 1 shows that in certain cases of acute ischemic stroke, the pace or speed of neural circuit loss in a typical large vessel supratentorial acute ischemic stroke can be very rapid. Table 1: Estimated rates of neural circuit loss in typical large vessel, supratentorial acute ischemic stroke [Table 1]

[0006] It is also known that the values ​​presented above represent averages and that there is generally high variability in the values, depending on the available blood supply to the ischemic area via collateral circulation. Several factors, including time delays in decision making, time delays in initiating endovascular procedures, and delays during procedures, all of which may be on the order of only a few minutes, can have a significant impact on neural circuit loss and ultimately patient outcome.

[0007] A paper (Non-Patent Document 1), incorporated herein by reference, quantitatively demonstrates that fast reperfusion significantly improves patient outcomes. In particular, the study concludes that "aggressive time goals may contribute to an efficient workflow environment." Furthermore, the study quantitatively demonstrates that patients achieved significantly greater functional independence, especially when treated promptly (i.e., within 2.5 hours of stroke onset).

[0008] Importantly, it is now known that efficient workflow during the recanalization procedure (which is critical to the effectiveness and efficiency of the procedure) leads to better outcomes.

[0009] First, in diagnosing ischemic stroke to evaluate possible treatments, it is important for a physician to know where the blood vessel blockage is, how large the blockage is, where the dead brain tissue (the "core") is located, and how large and where the brain tissue that may have been affected by the ischemic event but that could potentially be saved (the "penumbra") is located.

[0010] The penumbra is tissue surrounding an ischemic event that may remain viable for several hours after the ischemic event due to perfusion of this tissue by collateral arteries, which may provide the penumbra tissue with sufficient oxygen, nutrients, and / or irrigation to prevent it from dying for a period of time.

[0011] In the management of acute ischemic stroke, endovascular treatment of acute ischemic stroke due to large vessel occlusion in the anterior circulation has become the standard of care for certain patients. That is, patients with specific symptoms (stroke symptoms of a certain severity) benefit from early and prompt endovascular treatment to open the blocked vessel. Generally, endovascular treatment involves an interventionalist advancing a series of catheters toward the clot from the patient's groin, through the femoral artery, the descending aorta, the aortic arch, and into the cervical and cerebral arterial system. After access to the clot is achieved through catheter placement, a clot retrieval and / or clot aspiration device is deployed through the catheter to remove and / or aspirate the clot from the clot site. Access can also be gained from other areas, increasingly via the radial artery, or minimally via the carotid artery.

[0012] There are many anatomical and situational considerations that can affect the severity and ultimate treatment of an ischemic stroke. Importantly, as noted above, while a blood clot severely impacts blood flow to the ischemic area, some blood flow may reach the ischemic area if collateral arteries function to at least partially perfuse the affected area.

[0013] The most common large vessel occlusion treated endovascularly is the M1 segment of the middle cerebral artery (MCA). When a patient has an M1 occlusion, the area supplied by the M1 experiences a dramatic reduction in blood supply. As a result, distal nerve cells begin to function poorly, and the patient becomes symptomatic.

[0014] Recanalization procedures utilize a wide range of equipment and techniques to access and effectively remove blood clots. Endovascular surgeons typically have several tools at their disposal, including a wide variety of guide catheters, balloon guide catheters, guidewires, diagnostic catheters, microcatheters, microwires, stents, and other tools useful for different procedures and patient presentations, each with its own unique characteristics, features, and functions. Most, if not all, of the above tools are disposable and expensive. Therefore, there is an incentive to continue designing new tools that can achieve these goals using faster procedures (i.e., fewer procedures), fewer tools, and / or lower costs, so long as similar or better results can be achieved. Furthermore, minimizing the number of catheters utilized can help reduce the likelihood of errors and / or undesirable outcomes that may result from complex procedures.

[0015] As mentioned above, endovascular procedures in the brain are commonly performed by gaining access to the arterial vasculature from the patient's groin by puncturing the common femoral artery and inserting an arterial sheath.

[0016] Next, under fluoroscopic (X-ray) guidance, a catheter system (usually a coaxial system including a guide catheter (GC) or balloon guide catheter (BGC), a diagnostic catheter (DC), and a guidewire (GW)) is advanced through the descending aorta until it reaches the aortic arch.

[0017] The diagnostic catheter has a shaped tip that is used to hook the target blood vessel, and with the help of a guidewire, the diagnostic catheter is advanced to the target artery. Then, a guide catheter / balloon guide catheter is advanced over the diagnostic catheter so that the tip of the GC / BGC enters the target carotid artery.

[0018] At this stage, the diagnostic catheter and wires are removed, leaving the GC / BGC as a direct conduit from outside the body to the target carotid artery. It should be noted that the GC / BGC takes up space and has an outer or outer diameter (OD) and an inner or inner diameter (ID), which limit the size of any further devices advanced through the GC / BGC. The maximum outer diameter of the GC / BGC is dictated, among other things, by the inner diameter of the arterial sheath.

[0019] A catheter designed for intracranial access is then advanced through the guide catheter, which typically consists of one of two approaches. a. Microcatheters and microwires, or b. Triaxial system consisting of a distal access catheter (DAC), a microcatheter, and a microwire.

[0020] For approach a: Once the microcatheter and microwire have crossed the clot, remove the microwire and deploy the stent retriever, slowly crossing the clot. While applying aspiration through the guide catheter (and inflating the balloon if a BGC is used), remove the stent retriever, capturing the clot and establishing reperfusion.

[0021] In approach b: The DAC is placed proximal to the clot. In one approach b1, the clot is crossed using a microcatheter, the microwire is removed, and then a stent retriever is deployed. The stent retriever and DAC are then typically removed together while aspirating from the DAC. In the second approach b2, an attempt is made to directly capture the clot without using a stent retriever, by aspirating from the DAC.

[0022] Navigating a catheter and / or stent retriever system into a blood clot and performing a procedure involving highly complex and variable physical dimensions of a patient's anatomy presents various challenges and / or limitations.

[0023] For example, one particular consideration is that stroke typically affects older adults, and as individuals age, the tortuosity of the aortic arch typically increases, often making accessing the carotid artery more difficult. In particular, the highly tortuous combination of the aortic arch and carotid artery can make it difficult to advance a catheter system. This is because the high bend angle and friction can cause the catheter to prolapse into the ascending aorta and thus prevent it from advancing through the desired vessel. In other words, when pushing a catheter system through a tight bend, the system may seek the path of least resistance and end up being pushed in the wrong direction. Furthermore, tortuosity can prevent the catheter from advancing further. The combination of sharp turns and the origin of another artery, as is often the case in the ophthalmic segment of the internal carotid artery, can be a common site for such catheters to get stuck.

[0024] Another consideration is the size of the catheter systems available and the need to provide GC / BGC support for the advancement of smaller catheters. When a smaller catheter is supported by a larger catheter, the OD / ID of the smaller inner catheter is limited by the inner diameter of the larger support catheter.

[0025] (Catheter performance) As mentioned above, two categories of catheters used in brain procedures are diagnostic catheters and guide catheters. Diagnostic catheters are generally used to gain access to the area of ​​interest, while guide catheters are used to support and guide additional equipment, including diagnostic catheters, guidewires, balloons, stents, microwires, and other catheters, that may be required for a particular surgical procedure.

[0026] Typical diagnostic catheters range from 4F to 6F (French) and are 65 to 125 cm long. They can have a braided wall and generally have a soft tip with various shapes to better fit specific vessels. DCs can be designed with a variety of stiffnesses, from relatively soft to very stiff.

[0027] Guide catheters are generally larger (e.g., 6-9F) and have lengths of 80-100 cm. Guide catheters generally have a reinforced structure with a fairly stiff shaft to provide retrograde (i.e., retrograde) support for advancing any additional devices listed above. However, guide catheters can generally only be advanced up to the carotid artery in the neck because the stiffness of the guide catheter, combined with the narrowness and curvature of the vessel, prevents further advancement.

[0028] From an anatomical point of view, a catheter typically passes through various zones of the vasculature, i.e., the abdominal and thoracic vasculature between the femoral artery and the aortic arch (approximately 50-75 cm), the cervical vasculature (approximately 15-20 cm), and finally the cranial / cerebral vasculature (approximately 10-15 cm), with vessels that narrow progressively from 2.5 cm in the aorta to less than 3 mm in the cerebral vessels.

[0029] Various properties and geometries can also be incorporated into the design of both diagnostic and guide catheters. Trackability: The ability of a catheter to slide over a guidewire, especially through tortuous (sharply curved) vessels. Pushability: The ability to advance the tip or head of the catheter based on operator input from the hub (i.e., outside the body). Torqueability: The ability of the operator to steer the tip of the catheter based on a twist at the hub. Tip or Head Shape: The shape of the catheter tip or head assists the operator in navigating the distal tip of the catheter through particular anatomical features. For example, diagnostic catheters may have shapes that are flush, straight, simple curved, complex curved, diagonal curved, or double curved, among others. Such shapes may be classified as simple or complex. · Stiffness: The ability of the catheter to bend and support the catheter as it moves through a curve.

[0030] (Catheter structure) Each catheter may be constructed from multiple materials with various structures and / or layers within the catheter wall structure to impart specific properties or functional characteristics to the catheter, including: Surface coating: The surface coating preferably reduces clot formation, has a low coefficient of friction and / or antibacterial properties. Reinforcement: An internal wire braid is used to provide torque control / stiffness properties to the catheter. Polymer Layers: Different polymers can be used to provide different structural properties to the catheter body. For example: Polyurethanes can be made soft and pliable and therefore can follow the guidewire more effectively, although their coefficient of friction is relatively high. Nylon can be used for its hardness and ability to withstand relatively high flow rates of liquids passing through it.

[0031] The selection of a particular catheter or catheter system is typically determined by the skill, experience, and preferences of a particular interventionist.

[0032] Some typical properties of various catheters are summarized in Table 2. Table 2: Overview of catheter properties [Table 2(1)] [Table 2(2)]

[0033] (A typical endovascular procedure for treating ischemic stroke) As mentioned above, when an endovascular surgeon begins a procedure, access to the vascular structure is typically gained through the groin, however, as discussed below, other access areas are increasingly being used, including the radial artery.

[0034] After the groin puncture, variations of the following steps are performed to advance various catheters through the vasculature to the target site of interest. Typically, in the case of procedures using a balloon guide catheter and stent (i.e., a clot retrieval device), these steps include: Step A: Accessing the aortic arch a) After groin puncture, the sheath is deployed. The sheath serves as the access port to the body, and typically 15 cm is inserted into the femoral artery. The sheath has an inner diameter of approximately 8 F. If the femoral and iliac arteries are highly tortuous, a longer sheath (usually 45 cm) can be used. b) The assembly consisting of a guide catheter (GC) / balloon guide catheter (BGC), diagnostic catheter (DC), and guidewire (GW) is advanced toward the aortic arch. The GC / BGC typically has an outer diameter of 8F (matching the sheath). The DC (4-6F outer diameter) is held within the BGC, and the GW (0.035 inch outer diameter) is held within the DC. Step B: Accessing the carotid and cerebral arteries a) Manipulate the DC to gain access to the desired carotid artery. b) After carotid access is gained, the GW is advanced towards the occlusion site (but within the cervical carotid artery), typically 20-30 cm. c) After advancing the GW (or simultaneously and / or sequentially), the DC is advanced over the GW to gain access to the occlusion site. This can occur in a simultaneous and / or sequential process, depending on the specifics of the particular patient. However, this step can pose a significant problem. The design of the DC allows it to hook onto the relevant vessel. Typically, the tip (distal 5 cm) is pre-shaped, and diagnostic catheters are generally stiff and prone to torque. While these characteristics allow for vessel hooking, they can also work against the interventionalist when advancing the DC over the wire. Namely, the tip of the DC is relatively stiff within the carotid artery, preventing it from sliding over the GW, potentially causing the entire system to prolapse into the ascending aorta. d) Another approach is to advance the BGC while leaving the DC at its vascular origin, rather than advancing the DC. This solution sometimes works, but often suffers from the same problems due to the stiffness of the guide catheter. Step C: Placement of the guide catheter (GC) and balloon guide catheter (BGC) a) The GC / BGC is advanced over the DC and GW so that access is also gained to a straight section of the carotid artery, typically the cervical internal carotid artery. b) Then, DC and GW are completely removed. Step D: Microcatheter / microwire placement a) The microcatheter (MC) and microwire (MW) are guided together through the BGC all the way to the clot so that the distal tips of the MC and MW are positioned just past the distal edge of the clot. b) Once the MC is placed, remove the MW. Step E: Stent deployment a) A stent (ie, a clot retrieval device) is advanced through the MC until the distal tip of the stent is adjacent to the distal end of the MC. b) While holding the stent in place, pull back on the MC to expose the stent. When exposing the stent, the stent will extend into the clot so that it engages the clot. Step F: Clot removal a) Inflate the BGC to stop antegrade flow and generate retrograde flow (suction) through the BGC. b) At the same time, the stent, now engaged with the clot, along with the MC, is pulled proximally out of the body through the BGC. c) Perform a check angiogram through the BGC to determine if clot retrieval was successful. If not, steps E and F may be repeated. d) Once successful reperfusion has been achieved, the BGC, stent and clot are removed from the body.

[0035] (Variation) As a variation of this procedure, a distal access catheter (DAC) (4-6.0F) can be added to the procedure. This can be done in one of two ways: A: Suction technique i. According to this procedure, after gaining access to the cervical internal carotid artery using a guide catheter and DC, a guide catheter (GC), which may or may not be a BGC, is placed into the cervical internal carotid artery. ii.Remove DC. iii. The triaxial system consisting of the DAC (aspiration catheter), MC, and MW is advanced toward the intracranial circulation with the goal of bringing the tip of the DAC to the surface of the clot. An integrated support catheter (ISC), described in U.S. Patent No. 5,629,629 and incorporated herein by reference, can be used to improve / assist navigation through these arterial systems. To accomplish this, the MC and MW may need to be positioned posterior to the clot. Typically, in this case, the DAC would have a maximum size of 6F. Catheters larger than this are not possible because they require a larger guide catheter for support in the neck and do not have sufficient distal flexibility to navigate / pass through tighter curves. iv. Remove MW and MC (and / or ISC). v. If the DAC is on the surface of the clot, suction is applied through the DAC until the clot is successfully retrieved or the endovascular surgeon decides to try an alternative approach. Localized suction has the advantage that more suction pressure is likely to be transmitted to the clot. However, as discussed below, there are several possibilities when suction is used. Other disadvantages of the DAC are discussed below. Solumbra procedure i. The initial part of this procedure is the same as the aspiration procedure (i.e., steps A(i)-A(iii)). ii. However, once the MC has crossed the clot and the DAC is at the clot surface, the MW is removed and the stent is deployed across the clot. iii. The MC and stent are then removed while suction is being applied to the DAC. Thus, the suction pressure is immediately adjacent to the clot, rather than from the neck as with a BGC. Similarly, the stent enters the DAC while still in the intracranial vessel, which reduces the chance of losing the clot when it becomes trapped.

[0036] If the stentless aspiration procedure is not successful in removing the clot, a BGC can be placed in place followed by deployment of a GW, MC and stent.

[0037] In either approach, the application of suction pressure can achieve a variety of results. Generally, a typical DAC (aspiration catheter) is smaller than most clots, with the DAC having a maximum inner diameter ranging from 0.053 to 0.068 inches (corresponding outer diameter of 6F), but the size / OD of the clot will be the same size as the ID of the vessel in which it lodges (the clot is typically an embolus from a more proximal source, such as the heart or carotid artery, and will continue to migrate distally until the embolus size matches the vessel size). Therefore, there is a difference between the size of the DAC's distal tip opening and the size of the clot and / or vessel. Furthermore, most intracranial vessels are highly tortuous, and the DAC tends to remain on the outside of the curve as it advances. As a result, the distal tip of the DAC may not be perpendicular to the vessel wall and / or may be partially spaced from the vessel wall, such that the clot partially engages the outer edge of the DAC.

[0038] Furthermore, if the clot is "significantly" larger than the DAC, suction through the distal tip of the DAC generally will not achieve ingestion of the clot; rather, the most proximal portion of the clot will "stuck" at the distal tip of the DAC, and most of the clot will not be drawn into the DAC during suction because it is not very compressible.

[0039] Importantly, clot properties vary greatly in terms of consistency / rigidity / internal cohesion etc., so that the ultimate application of suction and / or proximal pressure can result in: a) The entire clot is ingested by the DAC (desirable). b) The clot is partially broken down into one or more small pieces, with the proximal pieces being completely ingested by the DAC, but pieces potentially migrating distally (which is undesirable). c) The clot is not ingested by the DAC and blocks the distal tip, necessitating removal of the DAC with only a partially ingested clot (a more favorable but potentially less rapid end result). d) As in c), fibrin-rich zones of the clot can become lodged in the DAC, necessitating removal of the DAC to remove part of the clot. In some cases, the clot may have non-fibrin-rich zones, which can result in smaller fragments breaking away from the lodged area and migrating further distally (which is undesirable). e) The clot does not fully engage and / or is not ingested by the DAC, leaving the clot in place (which may lead the surgeon to consider deploying a stent, which is less desirable).

[0040] Overall, of all these possibilities, complete ingestion of the clot is most desirable because it a) prevents fragmentation, b) prevents distal embolization, and c) transfers suction pressure to the next portion of the clot as the more proximal portion of the clot is sucked into the catheter. However, as mentioned above, DACs generally have an upper size limit, which can result in a large size mismatch between the vessel / clot and the DAC.

[0041] Furthermore, once a clot is deemed trapped, it is generally necessary to fully withdraw the DAC from the body so that a check angiogram can be performed to determine whether the clot has been completely removed and whether any smaller fragments remain.

[0042] As previously mentioned, a BGC is used to allow the surgeon to stop forward blood flow and is necessary to minimize the risk of the clot shearing distally and embolizing if the DAC is removed with a partially ingested clot. That is, because the diameter of the clot (and stent, if used) can be larger than the lumen of the BGC, there is a high likelihood that a portion of the clot will shear off and embolize distally when the DAC is removed (with or without the stent). Therefore, inflating the balloon to stop forward flow can reduce this risk. However, using a BGC reduces the size of the DAC because it must reside within the BGC.

[0043] Therefore, it is possible to advance a single large outer diameter catheter (e.g., 7F or larger) from the groin to the clot (e.g., at the M2 level or above), thereby significantly reducing the risk of causing distant embolism, the time to complete the aspiration procedure, and the cost of performing such a procedure, as long as the distal opening of the larger opening is available to fully engage the clot by fully ingesting it rather than holding only its proximal end at the tip due to aspiration pressure. However, challenges include the ability to advance a large OD catheter into the cerebral arteries, due to the difficulty of maneuvering such a device through tight curves and the common practice of using it within GC / BGC.

[0044] Furthermore, in the era of coronavirus, hospital treatment procedures have been modified to minimize risks to all healthcare workers and patients, resulting in stricter separation between personnel when preparing and performing procedures. These separation procedures reduce the efficiency of medical practices because it takes time to move medical equipment to the designated location. Therefore, there is now increased motivation to design devices, kits, and processes to overcome the inefficiencies created by coronavirus. [Prior art documents] [Patent documents]

[0045] [Patent Document 1] U.S. Patent No. 10,456,552 [Non-patent literature]

[0046] [Non-Patent Document 1] “Analysis of Workflow and Time to Treatment and the Effects on Outcome in Endovascular Treatment of Acute Ischemic Stroke: Results from the SWIFT PRIME Randomized Controlled Trial” (Radiology. 2016 Jun;279(3):888-97. doi: 10.1148 / radiol.2016160204. Epub April 19, 2016) Summary of the Invention

[0047] In accordance with the present invention, systems and methods are provided for improving the efficiency and effectiveness of surgical procedures.

[0048] In a first aspect, the present invention provides a Distal Entry Point (DEP) to Brain Aspiration (D2BA) catheter for use in an endovascular procedure to gain access to the carotid arteries and cerebral arteries of a patient's brain and aspirate one or more intracranial blood clots from the cerebral arteries, the D2BA catheter for placement within the patient's human blood vessels between the DEP and the cerebral arteries of the brain comprising: a soft distal tip region having a distal length sufficient to extend from a level 1 or level 2 arterial segment or equivalent of a cerebral artery to a superior carotid vessel, the soft distal tip region having a stiffness that allows movement through the level 1 or level 2 arterial segment of the cerebral artery and an outer diameter (OD) of 6F to 10F; and a proximal region having a stiffness greater than that of the soft distal tip region, the proximal region having a length sufficient to extend outside the patient via the DEP, the D2BA catheter allowing aspiration through the D2BA catheter to remove the one or more blood clots.

[0049] In various embodiments, The soft distal tip region and proximal region have sufficient flexibility and axial and radial compressive stiffness to allow the soft distal tip region to be advanced over a guidewire (GW) and diagnostic catheter (DC) and to position the distal tip of the soft distal tip region near the upper neck / base of the skull without an external support catheter. The soft distal tip region and proximal region have sufficient flexibility and compressive stiffness in the axial and radial directions so that when the soft distal tip region is advanced over the guidewire (GW) and diagnostic catheter (DC) and positioned near the upper neck / base of the skull, the D2BA catheter will not come out of the carotid artery even when the guidewire and diagnostic catheter are removed. The soft distal tip region and proximal region have sufficient flexibility and axial and radial compressive stiffness so that when the GW and DC are removed, the microwire (MW) and integrated support catheter (ISC) can be advanced to the distal tip through the D2BA catheter, and the D2BA catheter can be further advanced over the MW and ISC until the distal tip substantially engages the cerebral artery wall adjacent the clot. ·D2BA catheters have a wall thickness of 0.013 inches or less. The D2BA catheter has an outer diameter (OD) of 7F and a distal length extending from the superior carotid vessels to the level 2 segment of the middle cerebral artery, or from the distal cervical artery to the basilar artery or equivalent. Distal length is 17-25cm. · The D2BA catheter has an outer diameter (OD) of 8F and a distal length extending from the superior carotid vessel to the distal level 1 segment of the middle cerebral artery. Distal length is 15-23 cm. The D2BA catheter has an outer diameter (OD) of 9F and a distal length extending from the superior carotid vessel to the proximal level 1 segment of the middle cerebral artery or equivalent. Distal length is 13-21 cm. · The D2BA catheter has an outer diameter (OD) of 10F and a distal length extending from the superior carotid vessel to the distal segment of the internal carotid artery or equivalent. Distal length is 12-16 cm. The soft distal tip region comprises at least one polymer section having a composition that provides axial stiffness and flexibility for a particular linear position of the D2BA catheter. The proximal region comprises at least one polymer section having a composition that provides axial stiffness and flexibility for a particular linear position of the D2BA catheter. The D2BA catheter has a torsional stiffness that allows torque applied to the proximal zone to be transmitted to the distal tip of the distal zone, enabling rotational movement of the distal tip within the vessel, with the distal tip defining an oblique angle ranging from 10 to 30 degrees relative to the vertical cross section of the D2BA catheter.

[0050] In another aspect, the present invention provides an intravascular catheter system comprising: a D2BA catheter; and a second aspiration catheter having an outer diameter maximized to operate within the D2BA catheter and a length sufficient to extend to a position substantially equivalent to the distal tip of the D2BA catheter, the second aspiration catheter being configured to be positioned adjacent to the distal tip of the D2BA catheter and to apply aspiration pressure to a proximal end of a blood clot via the second aspiration catheter while within the D2BA catheter. In one embodiment, the second aspiration catheter has a proximal end and a proximal end lock, the proximal end lock being engageable with a proximal region of the D2BA catheter to prevent the second aspiration catheter from extending beyond the distal tip of the D2BA catheter.

[0051] In another aspect, the present invention provides an intravascular catheter system comprising: a D2BA catheter; and a cooling catheter having an outer diameter maximized to operate within the D2BA catheter and a length sufficient to extend to a position substantially equivalent to the distal tip of the D2BA catheter, the cooling catheter configured to deliver cooling fluid through the cooling catheter to the distal tip of the D2BA catheter, wherein the combination of the D2BA catheter and the cooling catheter provides sufficient insulation to allow effective flow of cooling fluid through the insulated catheter to effectively cool brain tissue after clot removal.

[0052] In various embodiments, The D2BA catheter has an outer diameter (OD) of 8F, the cooling catheter has an outer diameter (OD) of substantially 6F, and the cooling catheter has a wall thickness of 0.020 to 0.03 inches, preferably 0.026 inches. The wall thickness of the cooling catheter is substantially constant along the length of the cooling catheter, including insulation to the distal tip of the cooling catheter.

[0053] In another aspect, the present invention provides an intravascular catheter system comprising: a D2BA catheter; and a secondary D2BA catheter having an outer diameter maximized to operate within the D2BA catheter and a length sufficient to extend beyond the distal tip of the D2BA catheter, the secondary D2BA catheter configured to enable advancement of the secondary D2BA catheter to a position beyond the distal tip of the D2BA catheter and to apply suction pressure to a proximal edge of a secondary clot distal to the clot via the secondary D2BA catheter.

[0054] In another aspect, the present invention provides an intravascular catheter system comprising a D2BA catheter, a diagnostic catheter (DC) and a guidewire (GW) for internally supporting advancement of the D2BA catheter into a carotid artery, an integrated support catheter (ISC) having an outer diameter maximized for operative movement within the D2BA catheter, a length sufficient to extend beyond the distal tip of the D2BA catheter, and a distal taper for supporting the distal tip of the D2BA catheter during advancement of the D2BA catheter into a cerebral artery, a microwire (MW) configured to operate within the ISC and having a length sufficient to extend beyond the distal tip of the ISC for advancing the ISC and the D2BA catheter into a cerebral artery, and a guidewire (GW) for supporting the D2BA catheter. a secondary D2BA catheter having an outer diameter maximized to operate within the secondary D2BA catheter and having a length sufficient to extend to a position beyond the distal tip of the D2BA catheter, the secondary D2BA catheter being configured to enable advancement of the secondary D2BA catheter to a position beyond the distal tip of the D2BA catheter and to apply suction pressure to a proximal edge of a secondary clot distal to the clot via the secondary D2BA catheter; a secondary integrated support catheter (ISC) having an outer diameter maximized to operate within the secondary D2BA catheter and having a length sufficient to extend to a position beyond the distal tip of the secondary D2BA catheter; and a secondary microwire (MW) configured to operate within the secondary ISC and having a length sufficient to extend to a position beyond the distal tip of the secondary ISC.

[0055] In another aspect, the present invention provides an intravascular catheter system comprising: a D2BA catheter; and a stent configured for operation within the D2BA catheter, the stent operably connected to a pusher wire having a length sufficient to extend beyond the distal tip of the D2BA catheter to enable deployment of the stent from the distal tip of the D2BA catheter.

[0056] In another aspect, the present invention provides a kit for use in an intravascular procedure for accessing cervical and cerebral arteries and aspirating intracranial clots from cerebral arteries, the kit comprising: an intravascular catheter for placement within the human vasculature between a distal entry point (DEP) and a cerebral artery, the kit comprising a D2BA catheter; at least one diagnostic catheter (DC), each DC having an outer diameter that fits and slides within the D2BA catheter, each DC having a pre-formed tip for accessing various anatomical structures of the aortic arch, and having a length longer than the D2BA catheter; and a guidewire (GW) having a diameter that fits and slides within the DC and having a length longer than the DC.

[0057] In various embodiments, The kit further includes an internal support catheter (ISC), the ISC having an outer diameter that fits and slides within the D2BA catheter and a tapered distal zone for supporting and translating the distal tip of the D2BA catheter within tightly curved arteries during advancement of the D2BA catheter into a cerebral artery. · The kit has two or more DCs. The kit further includes a suction catheter, the suction catheter having an outer diameter maximized to operate within the D2BA catheter and a length sufficient to extend to a position substantially equivalent to the distal tip of the D2BA catheter. The kit further includes a cooling catheter, the cooling catheter having an outer diameter maximized to operate within the D2BA catheter and a length sufficient to extend to a position substantially equivalent to the distal tip of the D2BA catheter. The kit includes a second D2BA catheter sized to fit within the D2BA catheter, and a corresponding second ISC and second MW, each having a length greater than the D2BA catheter and sized to fit within the second D2BA catheter.

[0058] In another aspect, the present invention provides a cooling catheter for delivering an effective amount of cooling fluid through a D2BA catheter, the cooling catheter comprising a catheter having an outer diameter maximized to operate within the D2BA catheter and having a length sufficient to extend to a position substantially equivalent to the distal tip of the D2BA catheter, the cooling catheter configured to deliver cooling fluid through the cooling catheter to the distal tip of the D2BA catheter, the combination of the D2BA catheter and the cooling catheter providing sufficient insulation to allow effective flow of cooling fluid through the insulated catheter to effectively cool brain tissue following clot removal. In one embodiment, the wall thickness of the cooling catheter is substantially constant along the length of the cooling catheter and includes insulation to the distal tip of the cooling catheter.

[0059] In another aspect, the present invention provides an endovascular method for gaining access to carotid and cerebral arteries, comprising placing a catheter system within the human vasculature between a distal entry point (DEP) and a cerebral artery, and aspirating a cerebral clot in one of said cerebral arteries, said endovascular method comprising: a) introducing a catheter system including a D2BA catheter, a guidewire (GW) and a diagnostic catheter (DC) via a DEP; b) advancing the catheter system into the aortic arch; c) advancing the GW and the DC to the desired carotid artery and maneuvering the GW into the desired carotid artery; d) advancing the D2BA catheter to the desired carotid artery above the DC and the GW; e) removing the DC and the GW; f) introducing an inner support catheter (ISC) having a tapered distal section for supporting the distal end of the D2BA catheter and adapted to facilitate movement of the distal end through tight curves in the cerebral vasculature, and an ISC microwire (ISC MW); g) advancing the ISC and the ISC MW into the cerebral artery containing the clot; h) advancing the D2BA catheter to the proximal surface of the clot and removing the ISC and the ISC MW; i) applying suction of the clot through the D2BA catheter.

[0060] In another embodiment, the method further comprises: j) after applying suction to dislodge the clot in step i, performing a check angiogram to determine whether the entire clot has been dislodged and whether one or more distal emboli are present; and if one or more distal emboli are present, k) advancing a second D2BA catheter sized for coaxial movement within said D2BA catheter with a second ISC and a second ISC MW to the proximal aspect of said distal embolism; l) applying suction to the second D2BA catheter and removing the distal embolus by suction or removal of the second D2BA catheter.

[0061] In various embodiments, The DEP is the radial artery, and the D2BA catheter has a proximal length compatible with advancement from the radial artery puncture. The DEP is the femoral artery, and the D2BA catheter has a proximal length suitable for advancement from the femoral artery puncture. Step i includes applying one or more first pressure pulses through the D2BA catheter to assist in engaging the distal tip of the D2BA catheter with the clot, and then applying at least one second suction pulse to aspirate the clot. The method further includes comparing the predetermined pressure pulse to a measured response pressure at the aspiration pump and adjusting subsequent pressure pulses based on the measured response pressure. The step of adjusting subsequent pressure pulses takes into account pressure response data from multiple patients collected and analyzed from similar procedures. Suction is performed via suction pumps operatively connected to the internet and a central analysis computer system, where pressure response data from the different pumps is received and analyzed by the central computer system and pump pressure algorithms are updated for the different pumps via the internet. Pump pressure algorithm takes into account catheter material, brand and / or size. If aspiration fails, introduce the suction catheter into the D2BA catheter, advance the suction catheter to the distal tip of the D2BA catheter, and apply aspiration through the D2BA catheter. If aspiration is successful, introduce the cooling catheter into the D2BA catheter, advance the cooling catheter to the distal tip of the D2BA catheter, and flow cooling fluid through the cooling catheter to cool the brain tissue. The method further includes flowing a brain nutrient fluid through the cooling catheter. The cooling catheter is an ISC with proximal insulation, and after the ISC is removed and suction is completed, the ISC is reintroduced and brain nutrient solution is flowed through the ISC.

[0062] In another aspect, the present invention provides a method for effectively removing foreign blood clots having fibrin-rich regions and erythrocyte-rich regions from cerebral blood vessels, the method comprising: a) positioning a D2BA catheter adjacent to the proximal end of the clot in the cerebral vessel; b) applying a first pressure pulse to effect suction of a first proximal region of the clot; c) applying a second pressure pulse to effect suction of a second distal region of the clot; Includes.

[0063] In various embodiments, The first proximal region is a fibrin-rich region and the second distal region is a red blood cell-rich region. The method further includes monitoring a first return pressure wave after delivery of the first pressure pulse and adjusting the second pressure pulse based on the first return pressure wave.

[0064] In another aspect, the present invention provides a cooling device for controlling the temperature of coolant delivered through a cooling catheter, the cooling device comprising a fluid cooling module for delivering coolant to a proximal end of the cooling catheter, the fluid cooling module having a fluid pump and controller for pumping a calculated amount of coolant through the cooling catheter, the calculated amount based on modeling of heat transfer through the cooling catheter, modeling data for a D2BA catheter selected for the patient, patient data, and a desired coolant temperature at the distal end of the cooling catheter.

[0065] In another aspect, the present invention provides use of a D2BA catheter for accessing a cerebral artery without the support of a guide catheter and applying suction to one or more intracranial blood clots from the cerebral artery, the D2BA catheter comprising: a soft distal tip region having a distal length sufficient to extend from a level 1 or level 2 arterial segment or equivalent to an arterial vessel near the upper cervical / base of the skull for placement within the human vasculature between a distal entry point (DEP) and a cerebral artery, the soft distal tip region having an outer diameter (OD) of 6F to 10F; and a proximal region connected to the soft distal tip region at a junction, the proximal region having a length sufficient to extend outside the patient via the DEP and having an outer diameter substantially similar to the inner diameter of the soft distal tip region, the D2BA catheter allowing suction through the D2BA catheter to remove the one or more blood clots.

[0066] In one embodiment, the soft distal tip region and the proximal region have sufficient balanced flexibility and axial and radial compressive stiffness to allow the soft distal tip region to be advanced over a guidewire (GW) and diagnostic catheter (DC) and to position the distal tip of the soft distal tip region near the upper neck / base of the skull without an external supporting catheter.

[0067] In another embodiment, the soft distal tip region and the proximal region have sufficient balanced flexibility and axial and radial compressive stiffness such that when the soft distal tip region is advanced over the guidewire (GW) and diagnostic catheter (DC) and positioned near the upper neck / base of the skull, the D2BA catheter will not come out of the carotid artery even when the guidewire and diagnostic catheter are removed.

[0068] In another embodiment, the soft distal tip region and the proximal region have sufficient balanced flexibility and axial and radial compressive stiffness such that when the GW and DC are removed, a microwire (MW) and an integrated support catheter (ISC) can be advanced to the distal tip through the D2BA catheter, and the D2BA catheter is further advanced over the MW and ISC until the distal tip substantially engages the cerebral artery wall adjacent to the clot.

[0069] In another aspect, the present invention provides an intravascular catheter for use in an intravascular procedure, the intravascular catheter having a structure for gaining access to carotid and cerebral arteries and aspirating one or more intracranial clots from a cerebral artery, the intravascular catheter having a soft distal tip region having a distal length sufficient to extend from a level 1 or level 2 arterial segment of a cerebral artery or equivalent to an arterial vessel near the upper cervical / base of the skull for placement within the human vasculature between a distal entry point (DEP) and a cerebral artery, the soft distal tip region having an outer diameter (OD) of 6F to 10F, The D2BA catheter comprises a flexible distal tip region that is flexible and can ride over a diagnostic catheter (DC) and guidewire (GW) placed in the carotid artery, allowing access to the carotid artery through the aortic arch without causing prolapse of the DC and GW, and upon removal of the DC and GW, the D2BA catheter can be further advanced into a cerebral artery; and a proximal region that transitions to the soft distal tip region and has a length sufficient to extend to the outside of the patient via the DEP, allowing the D2BA catheter to be advanced to the carotid artery without the support of a guide catheter.

[0070] In another aspect, the present invention provides a distal entry point to brain aspiration (D2BA) catheter having an outer diameter greater than 6F and a length sufficient to extend from a distal entry point (DEP) outside the body to a clot in a level 1 or level 2 segment of a cerebral artery, wherein the D2BA catheter has sufficient axial flexibility / rigidity along its length to be advanced over a guidewire (GW) and a diagnostic catheter (DC) from the DEP to the distal tips of the GW and the DC when the GW and the DC are positioned at an upper cervical / near skull base level, such that the D2BA catheter can be advanced through the aortic arch with support only from the GW and the DC.

[0071] In another aspect, the present invention provides a distal entry point to brain aspiration (D2BA) catheter comprising a catheter, the catheter having an outer diameter of 6F to 10F and a length sufficient to extend from a distal entry point (DEP) outside the body to a cerebral artery clot; a soft distal tip zone having axial flexibility / stiffness along its length for advancing the D2BA catheter from the DEP over a guidewire (GW) and diagnostic catheter (DC) to the distal tips of the GW and DC when the GW and DC are located at an upper cervical / proximal skull base level, the soft distal tip zone having an outer diameter selected to substantially match the inner diameter of the artery in which the clot is located and a length extending from the clot to an upper cervical / proximal skull base level; and a proximal zone having axial flexibility / stiffness along its length for advancing the D2BA catheter, the proximal zone allowing the soft distal tip zone to be advanced through the aortic arch with only support from the GW and DC.

[0072] In another aspect, the present invention provides an aspiration catheter (AC) having an outer diameter greater than 6F and a length sufficient to extend from a distal entry point (DEP) to an arterial segment at or above level 1 of the brain, the AC having a distal region and a proximal region and a combination of axial flexibility and stiffness such that the AC can be advanced over a diagnostic catheter (DC) and a guidewire (GW) positioned between the DEP and the carotid artery without the DC and the GW protruding and without the support of a guide catheter (GC), the DC and the GW can be withdrawn from the AC without protruding from the AC, the AC can be advanced together with at least one microcatheter (MC) and microwire (MW) to a clot in an arterial segment at or above level 1, and aspiration can be applied from the AC to aspirate the clot.

[0073] In another aspect, the present invention provides an aspiration catheter (AC) comprising a catheter having an outer diameter of 6F to 10F and a length sufficient to extend from a distal entry point (DEP) to a clot in a cerebral artery, the AC having a distal region with a distal tip having a distal tip outer diameter substantially corresponding to the inner diameter of the cerebral artery in which the clot is located and a length extending from the clot to near the upper neck / base of the skull, the distal and proximal regions having a combination of axial flexibility and stiffness such that the AC is suitable for use as a diagnostic catheter (DC) positioned between the DEP and the carotid artery. and over a guidewire (GW), the DC and the GW can be advanced without prolapse and without the support of a guide catheter (GC), the DC and the GW can be removed from the AC without prolapse of the AC, the AC can be advanced together with at least one microcatheter (MC) or integrated support catheter (ISC) and a microwire (MW) to a clot in an arterial segment at level 1 or above, and the distal tip can be aspirated from the AC in close proximity to the clot to aspirate the clot.

[0074] In another aspect, the present invention provides an integrated support and cooling catheter (ISCC) for assisting in the advancement of a D2BA catheter, the ISCC allowing for the flow of coolant through the ISCC after aspiration of a blood clot through the D2BA, the ISCC comprising a catheter having a tapered distal zone for supporting the distal tip of the D2BA as it passes through tortuous sections of a patient's cerebral vasculature, and an insulated proximal zone that allows for the introduction of coolant into the proximal end of the ISCC at 1-3°C and for the coolant to exit the ISCC at 2-8°C. [Brief explanation of the drawings]

[0075] The present invention will now be described with reference to the drawings.

[0076] [Figure 1A] 1 is a sketch of a typical aortic arch and associated vessels according to the prior art. [Figure 1B] 1 is a schematic diagram showing middle vessel occlusion sites (MeVOs) according to the prior art. These are generally defined as sites in the anterior circulation including (A): the proximal M2 segment, the distal M2 segment, the M3 segment, the A2 segment, and the A3 segment. MeVO sites in the posterior circulation are generally defined as the P2 or P3 segment (B). [Figure 1C] FIG. 1 is a schematic diagram of a blood clot Y lodged within the MCA at the M1 segment according to the prior art. [Figure 2A] FIG. 1 is a schematic diagram showing the advancement of a guidewire, diagnostic catheter, and catheter through the aortic arch of a G2BA and into the common carotid artery (CCA), according to one embodiment of the present invention. [Figure 2B] FIG. 1 is a schematic diagram illustrating the characteristics of a G2BA according to the present invention, including the structural parameters of axial stiffness, radial compressibility, axial compressibility, and torqueability. [Figure 3] 1A-1C are schematic diagrams illustrating steps of a procedure according to one embodiment of the present invention for placing a G2BA catheter in a cerebral artery of a patient. [Figure 3A]10 is a schematic diagram illustrating an additional step of a procedure according to an embodiment of the present invention for placing a G2BA catheter at a higher level within a patient's cerebral artery. [Figure 4] FIG. 1 is a schematic diagram illustrating the use of an integrated support catheter (ISC) to assist a G2BA catheter through a tortuous section of the brain cavity, in accordance with one embodiment of the present invention. [Figure 4A] FIG. 1 is a schematic diagram illustrating the use of two microcatheters as an integrated support catheter (ISC) to assist a G2BA catheter through a tortuous section of the brain cavity, in accordance with one embodiment of the present invention. [Figure 5A] 1 is a schematic diagram illustrating potential engagement of a suction catheter with a blood clot according to the prior art. [Figure 5B] 1 is a schematic diagram illustrating potential engagement of a suction catheter with a blood clot according to the prior art after suction has been applied. [Figure 5C] 10 is a schematic diagram illustrating potential engagement of a G2BA catheter with a blood clot after suction is applied according to one embodiment of the present invention. FIG. [Figure 5D] FIG. 1 is a schematic diagram showing a G2BA catheter with a beveled tip capable of torque transmission. [Figure 6A] FIG. 1 is a schematic diagram showing a blood clot lodged within a G2BA and an aspiration catheter proximal to the distal tip of the G2BA. [Figure 6B] FIG. 10 is a schematic diagram showing a G2BA catheter and a second G2BA catheter being used to perform secondary aspiration of distal emboli. [Figure 6C] FIG. 1 is a schematic diagram of the insulating / cooling catheter within the G2BA catheter. DETAILED DESCRIPTION OF THE INVENTION

[0077] (Theoretical basis) The inventors have recognized the limitations of current catheter designs and methods for aspirating blood clots from cerebral arteries.

[0078] (Terminology) The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It will be further understood that as used herein, the terms "comprises" and / or "comprising" specify the presence of stated features, steps, operations, elements, and / or components, but do not exclude 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.

[0079] Spatially relative terms, such as "distal," "proximal," "anterior," "posterior," "below," "lower," "upper," "upper," and the like, may be used herein for ease of description to describe the relationship of an element or feature to other elements or features, as shown in the figures. It will be understood that spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if features in the figures are inverted, an element described as "below" or "below" the other element or feature would then be oriented "above" the other element or feature. Thus, the exemplary term "below" can encompass both an orientation above and below. Features may be in other orientations (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein will be interpreted accordingly. Similarly, the terms "upward," "downward," "vertical," "horizontal," and the like are used herein for descriptive purposes only, unless otherwise indicated.

[0080] When an element is referred to as being "on," "mounted," "connected," "coupled," "in contact," etc., to another element, it will be understood that there may be intervening elements directly on, attached to, connected to, coupled to, or in contact with the other element. In contrast, when an element is referred to as being, for example, "directly on," "directly attached," "directly connected," "directly coupled," or "in direct contact with," there are no intervening elements present.

[0081] Although terms such as "first," "second," etc. may be used to describe various elements, components, etc. herein, it will be understood that these elements, components, etc. should not be limited by these terms. These terms are used only to distinguish one element, component, etc. from another element, component, etc. Thus, a "first" element or component discussed herein could also be referred to as a "second" element or component without departing from the teachings of the present invention. Furthermore, the order of operations (or steps) is not limited to the order shown in the claims or figures unless otherwise specified.

[0082] Structural parameters such as "axial stiffness," "radial compressibility," "axial compressibility," and "torqueability," as will be understood by those skilled in the art, can be described as relating to various functional characteristics of a catheter related to its performance or behavior in the human body during an intravascular procedure. That is, catheters as described herein are sophisticated pieces of medical equipment used in complex medical procedures that employ an assortment of other equipment (including the absence of various equipment components), and are more clearly and broadly defined in terms of their performance, as opposed to specific definitions utilizing numerical ranges.

[0083] Unless otherwise stated herein or expressly stated otherwise, in the following portions of this specification and the appended claims, all numerical ranges, amounts, values, and percentages relating to amounts of materials, elemental contents, times and temperatures, ratios of amounts, and the like may be read as if preceded by "about," even if the word "about" is not explicitly stated in conjunction with that value, amount, or range. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and appended claims are approximations that may vary depending on the desired properties sought to be obtained by the present invention. Each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques, without attempting to limit the application of the doctrine of equivalents to the scope of the claims. Typically, outer diameters of catheters are expressed in French (FR) units, while inner diameters (ID) of catheters are expressed in inches. When referring to the dimensions of a "sheath," French units are used to refer to the inner diameter.

[0084] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0085] Various aspects of the present invention will now be described with reference to the figures. However, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Moreover, the drawings are not necessarily drawn to scale, with the intention being to emphasize principles of operation rather than precise dimensions.

[0086] (Introduction) Figure 1A shows a typical aortic arch 5 and associated vessels, including the ascending aorta 5a, descending aorta 5b, left subclavian artery 5c, common carotid artery 5d, brachiocephalic artery 5e, right subclavian artery 5f, and internal carotid artery 5g. Figure 1B is a schematic diagram illustrating a middle vessel occlusion (MeVO). These are generally defined as the anterior circulation region (A), including the proximal M2, distal M2, M3, A2, and A3 segments. The posterior circulation MeVO region (B) is generally defined as the P2 or P3 segment. Figure 1C is a schematic diagram of a clot lodged in the M1 segment of the MCA. Associated vessels include the common carotid artery (CCA), ophthalmic artery (OA), internal carotid artery (ICA), anterior cerebral artery (ACA), and middle cerebral artery (MCA), including the M1 and M2 segments.

[0087] In accordance with the present invention, and with reference to FIGS. 2A and 3, a large size aspiration (LSA) catheter 10 is described, which has: 1) a distal zone 10a having a distal end 10b that can be positioned adjacent to a typical blood clot within a specific zone of the cerebral vasculature, including the level 2 segments of the middle cerebral artery and basilar artery (or higher) (collectively "target levels"); 2) a proximal zone 10c having a proximal end 10d that does not require external support (e.g., via a guide catheter (GC) or balloon guide catheter (BGC)) as the LSA catheter is advanced through the aortic arch and into the carotid artery; and 3) an outer diameter (OD) that is greater than 6 French and less than or equal to 10 French.

[0088] In the context of this specification, in various embodiments, the LSA catheter is referred to as a groin-to-brain aspiration catheter (G2BA), which refers to the most common access point (i.e., the groin) for performing endovascular neurovascular procedures. However, the LSA catheter is also referred to as a distal entry point (DEP) to cerebral catheter (D2BA), which contemplates distal entry points including both the femoral (groin) and radial arteries. That is, it is understood that other entry points for endovascular neurovascular procedures other than the groin are contemplated in accordance with the present invention. Generally, as described below, the length dimension of the proximal zone of the D2BA is adjusted based on the DEP, taking into consideration the respective distances from the groin entry point versus the radial entry point. As such, references to LSA, G2BA, and D2BA catheters are used herein.

[0089] Generally, G2BA catheters are defined as catheters useful for performing intravascular procedures in the brain that have a larger outer diameter (7-10F) and a correspondingly large inner lumen (inner diameter) extending from the proximal end 10d to the distal end 10b, with the lumen ID ranging from 0.066 inches to 0.105 inches (preferably 0.072 inches to 0.105 inches, and more preferably 0.078 inches to 0.105 inches, as determined based on the intended target level).

[0090] In general, the outer diameter at the distal end of the G2BA catheter is expected to closely match the lumen diameter of the target vessel, with the inner diameter of the G2BA being the largest possible (i.e., having the smallest wall thickness) that provides the stiffness necessary to perform the aspiration procedures described herein.

[0091] Thus, at one level, the present invention seeks to facilitate clot capture by aspiration by minimizing the diameter difference between the clot and the G2BA catheter. In this regard, it is recognized that while the ID of the G2BA catheter may not be equal to the vessel lumen (due to catheter wall thickness), minimizing this difference can substantially improve clot capture. It is further recognized that clots typically have some compressibility, and placement of a catheter with substantially the same outer diameter as the target vessel effectively wedges the catheter within the target vessel, improving aspiration pressure on the clot, as described in more detail below. It is also recognized that a larger G2BA lumen allows for higher aspiration forces to be applied without damaging the vessel intima.

[0092] Importantly, in the past, it was often impossible to advance larger sized aspiration catheters into the brain. This was because a larger guide catheter had to be advanced into the neck to externally support the aspiration catheter during advancement. The use of an external guide catheter reduced the effective size of the aspiration catheter that could be advanced through the guide catheter. Additionally, in the past, aspiration catheters could not be advanced over DC / GW due to the relative distal stiffness of such catheters. Furthermore, in the past, it was difficult to advance aspiration catheters through such vessels (e.g., the ophthalmic artery) due to their tortuous nature and the relative stiffness of their distal tips. While U.S. Patent No. 6,249,623 teaches that advancement of certain catheters through tortuous cerebral vasculature can be improved by utilizing an internal support catheter (ISC), the structure of the aspiration catheter has limitations.

[0093] As shown in Table 3, the G2BA is designed with different lengths and outer diameters (i.e., French size; referred to as "catheter size") that allow access to specific levels of the brain. These parameters are identified and discussed in Table 3. Table 3: Characteristics and properties of G2BA [Table 3(1)] [Table 3(2)] [Table 3(3)]

[0094] Importantly, the transition between the proximal and distal zones is preferably not abrupt, and it is understood that the transition zone may include multiple subzones that provide a transition between the properties of the proximal and distal zones. That is, the axial stiffness of the distal zone may gradually increase proximally, resulting in subzones with consistent G2BA physical properties over a 4-8+ cm segment, followed by a step into different subzones with different properties. For the proximal zones, these are representatively designated P1, P2, and P3 (where stiffness may increase from P1-P3), and for the distal zones, D1, D2, and D3 (where stiffness may decrease from D1-D3). As such, the transition point between the distal and proximal zones is generally considered to be a measured distance (relative to a particular target level) from the distal tip, where the transition point is the high carotid artery. In some embodiments, a specific radiopaque marker 40a may be incorporated at the transition point to assist the physician in visualizing the location of the transition point and the radiopaque distal tip marker 40. Table 4: Typical OD and ID sizes of catheters [Table 4]

[0095] The relative size of the G2BA catheter and the ability to deploy the G2BA to a level where the distal tip substantially engages the vessel lumen and is in close proximity to the clot offer many advantages over past systems, particularly improved time to access and the ability to capture the clot with aspiration.

[0096] The G2BA catheter eliminates the need for a GC or BGC by preventing (or substantially stopping) antegrade flow and the associated risk of microemboli being carried away during the procedure: the effective size of the G2BA relative to the vessel ID allows for gentle wedging of the distal tip within the target vessel to substantially prevent retrograde flow after the G2BA catheter is placed.

[0097] (Building G2BA) Catheters used to access regions of the brain are constructed using a variety of techniques to impart desired performance characteristics to the catheter, including pushability, torqueability, trackability, and hardness. Generally, catheters may be constructed from engineering polymers, including polyurethane, nylon, silicone rubber, polyethylene terephthalate (PET), latex, thermoplastic elastomers, and polyimides. Polymeric and metallic microfilaments may also be incorporated.

[0098] Typically, catheters are manufactured from an assembly of small portions of various blends of polymers that are extruded, thermoformed, and / or thermoset using a range of techniques, including casting and / or assembly on a mandrel. Each blend is designed to contain different properties. Thus, different subzones may have slightly different hardness properties along the length of either the proximal or distal zone, for example, as described above.

[0099] (Deployment method and use) The process of introducing a G2BA catheter in accordance with the methods of the present invention will now be described with reference to Figures 2A, 3, and 3A (referred to as the "G2BA method"). For purposes of illustration, Figures 2A, 3, and 3A assume access from the femoral artery and desired access to the M1 segment via the ICA. It should also be noted that the lengths of the devices in Figures 3 and 3A are not drawn to scale, and specifically, for clarity, the sections of the devices outside the body are not drawn to show consistent overall lengths in each step outlined below.

[0100] First, after arterial puncture, sheath 20 is deployed (Step 1). Femoral artery sheaths have a maximum inner diameter of approximately 12F (typically 9-10F). Access via the radial or brachial arteries utilizes sheaths with a maximum inner diameter of approximately 7F-8F.

[0101] Subsequently, or simultaneously, the assembly of the G2BA 10, diagnostic catheter (DC) 24 with tip 24a, and guidewire (GW) 26 (typically 0.035 inches) is assembled and gradually introduced into the sheath (step 2) and advanced to the aortic arch. The selected assembly of the G2BA, DC, and GW will be based on the location of the clot, along with the physician's assessment of the aortic arch access vessels and the patient's aortic arch anatomy / variability. That is, when planning the procedure, the physician will have determined the location of the clot and how to access it. In this example, if the clot is at the M1 level, requiring access via the common carotid artery (CCA) and ICA, an 8F G2BA may be selected in combination with the preferred DC to access the CCA. Alternatively, if the clot is located at the P1 level in the basilar system, requiring access via the right subclavian, a smaller (e.g., 7F) G2BA and a different DC may be selected and assembled.

[0102] As the GW and DC are advanced to the aortic arch, the distal tip 10b of the G2BA is also advanced and typically held within 20 cm of the aortic arch.

[0103] The DC and GW are manipulated to access the desired carotid artery (Step 2). The GW is generally held in substantially the same position as the DC during the carotid access gain step. During this step, the DC and GW are torqued, pushed, and / or pulled to hook the tip of the DC to the desired vessel. Once the DC / GW is in the desired vessel, the GW and DC are advanced together to advance both to the base of the skull (Step 3). For example, if there is severe tortuosity, stenosis, or occlusion at the origin of the internal carotid artery (ICA), initial access to the external carotid artery (ECA) may also be obtained. In certain situations, a second "buddy wire," i.e., a second GW, may be deployed to assist the physician in providing support to the system.

[0104] With the GW and DC held approximately at the base of the skull, the G2BA is advanced onto the DC / GW so that it follows the DC and GW until its distal tip is adjacent to the distal tips of the DC and GW (step 3). The G2BA's soft, undefined distal end allows it to easily follow the DC and GW. At this point, the soft distal end is completely within the carotid artery, and the stiff proximal portion of the G2BA is within the carotid artery, approximately 10 cm (8–12 cm) past the aortic arch. The GW and DC are typically not advanced beyond the base of the skull and are removed (step 4).

[0105] Importantly, because the rigid portion of the G2BA is within the carotid artery and the DC and GW have been removed (step 4), the risk of prolapse of the G2BA into the ascending aorta is virtually eliminated if further devices are introduced into the G2BA (step 5).

[0106] In step 5, a microcatheter (MC) or integrated support catheter (ISC) 28 and microwire (MW) 30 are introduced and advanced to the clot Y. Once the clot is reached with the MC or ISC and MW, the G2BA 10 is advanced over the MC or ISC to the surface of the clot. For reasons explained below, the use of an ISC is preferred. As shown in FIG. 4 , the ISC 28 is characterized by a distal taper 28a, a straight section 28b, and a proximal taper 28c (in various embodiments, the ISC may not have a proximal taper, and the straight section 28b may extend along the entire proximal length of the ISC), which aids in, or otherwise provides, an effective transition between the distal end 10b of the catheter and the microcatheter, forming a smooth extension of the distal end 10b of the catheter. That is, the ISC fills the distal end of the G2BA catheter and provides a smooth extension of the catheter, particularly when the catheter assembly is navigated through tightly curved areas of the vasculature 50. By stretching and engaging the vessel wall 50, the vessel wall exerts a force F1 transmitted through the ISC such that the ISC exerts a force F2 on the distal tip 10b of the G2BA, which in turn positions the G2BA to allow it to be more effectively pushed within the vessel 50. Thus, by selectively manipulating each of the G2BA, ISC, and MW, the physician can advance the G2BA over tortuosities.

[0107] The physician may consider the G2BA unlikely to become clogged and therefore an ISC is not required, but in most cases it is preferable to introduce an ISC instead of an MC in anticipation of the possibility that the G2BA may become clogged.

[0108] Additionally, as shown in Figure 4A, an alternative may be for the physician to use two or more microcatheters (29a, 29b) to ease the G2BA around tight curves. In this case, each microcatheter can be selectively advanced a short distance from the distal tip of the G2BA, providing alignment to prevent the G2BA from getting stuck.

[0109] The MC / ISC and MW are pushed forward and extend from the distal tip of the G2BA. By sequentially manipulating each of the MC or ISC, MW, and G2BA, they are gradually advanced to the clot.

[0110] Importantly, compared to previous aspiration catheters, the G2BA's larger outer diameter and relatively large distal tip are again noteworthy, allowing for further advancement.

[0111] A larger distal tip diameter generally means that the G2BA essentially occludes the vessel in which it resides, and therefore is more likely to align the distal tip of the G2BA perpendicular to the vessel, as shown in FIG. 5C, as opposed to being slightly deflected due to supporting pressure from the vessel wall, as shown in FIG. 5A. That is, as shown in FIG. 5A, a prior art AC that is smaller than the vessel may experience unequal pushing forces along the inner and outer edges of the catheter, resulting in the outer edge, with a larger force F3, extending one side of the distal tip AC further through the vessel compared to the inner edge and force F4, deflecting the distal tip at an angle θ. As shown in FIG. 5A, if the distal tip ACt is misaligned, applying suction pressure P1 may result in less effective pressure being applied because blood may backflow into the catheter, as shown by P2 and P3.

[0112] Additionally, a technique for improving clot capture with smaller ACs involves applying suction to the AC and waiting a period (typically 90 seconds) to allow the clot to potentially align with the AC and / or deform to engage the distal tip of the AC. However, as shown in FIG. 5B, application of suction pressure P1 can deform the clot Y around the AC, potentially preventing the clot from being aspirated and / or fragmenting the clot.

[0113] As shown in Figure 5C, the distal tip of G2BA is more likely to align with the clot, which will improve the chances of clot capture in many situations.

[0114] The G2BA has a larger distal tip opening and therefore an improved chance of being perpendicular to the vessel, making it more likely to align and seal against the vessel wall, thus allowing for more effective application of suction with less "leakage" around the distal tip.

[0115] (Methods for preventing clot fragmentation / embolization in new areas) In another aspect, the present invention provides methods for reducing clot fragmentation and / or embolization in new areas. As is well known, blood clots can be composed of different zones or segments with different compositions that affect the overall stiffness / cohesion of the clot. Generally, clots can range in composition and consistency between firmer, fibrin-rich zones / fragments and softer zones / fragments, where the cohesion between these zones may be relatively strong or weak. The fibrin-rich zones generally have strong cohesion holding the clot together, while other zones have weaker cohesion and are more susceptible to fragmentation. When using small aspiration catheters and / or when the clot is fibrin-rich, it is common for the clot to "stuck" at the tip of the catheter and become unable to be removed by aspiration. When a clot becomes stuck, removal of the AC is necessary, which has two major potential drawbacks. First, the act of removal can disrupt the patient's position, requiring time to reposition if necessary. Second, the act of removal can cause clot fragmentation, meaning that only a portion / fragment of the clot is removed, leaving a portion / fragment of the clot at the clot site. These clot fragments are smaller and may travel into distal vessels, making retrieval more difficult. Also, as the clot is removed, it may encounter the origin of other large vessels. For example, when a catheter is removed from the MCA, it crosses the origin of the ACA, which causes the clot to fragment, and portions of the clot may enter the ACA and cause a new stroke, commonly referred to as an infarct in new territory (INT).

[0116] If fragmentation occurs, after the first piece is removed, the AC must be returned to the surface of the clot to remove one or more remaining fragments, resulting in a significant time delay in reperfusion.

[0117] Thus, G2BA also provides a method for reducing clot fragmentation by improving the suction force applied to the clot at the intended level of G2BA, which increases the likelihood of complete ingestion of the clot and reduces the likelihood of requiring withdrawal of the G2BA, which can cause fragmentation.

[0118] Similarly, a clot that is not completely aspirated or dislodged may fragment into one or more additional pieces / emboli that travel to distal sites. Thus, G2BA also provides a method of reducing embolism in new areas by applying improved aspiration pressure to the clot, which increases the likelihood that any small fragments that would otherwise cause distal embolism will be aspirated along with the main fragment of the clot.

[0119] (Angled G2BA tip and torque-transmitting G2BA) Figure 5A shows that the tip of an AC catheter can deflect when pushing around a curve, such that the distal tip may have an angle θ relative to the vessel wall. Depending on the specific orientation of the distal tip and the specific proximal surface of the clot, this contact angle between the distal tip and the clot may either assist aspiration or, alternatively, adversely affect aspiration. For example, if the distal tip forms an oval opening and is oriented to improve the contact angle with the clot, aspiration may be facilitated; however, if the angled surface is not "parallel" to the proximal surface of the clot, the contact angle between the distal tip and the clot may similarly impair aspiration. In general, an angled surface increases the contact surface area, potentially further increasing the chance of ingesting the clot. In the past, aspiration catheters were not designed to apply torque and therefore were not designed to allow the contact angle to be controlled or altered.

[0120] Current catheters are made of soft materials, which means they cannot transmit torque. When torque (rotational force) is applied to the part of the catheter outside of its body, the force cannot be transmitted to the distal end, and instead the catheter itself is damaged.

[0121] In one embodiment, the G2BA is constructed so that approximately 100-120+ cm of the proximal portion is torqueable, thus transmitting torque forces only for the 15-20+ cm of the softer distal portion, making application of torque forces more likely to successfully rotate the distal tip. Figure 5D shows a G2BA 10 with a torqueable distal portion having a beveled distal tip 10b that can be torqued to improve the contact angle between the beveled distal tip and the clot. In general, it is often desirable to ensure that the outer distal tip is positioned on the outside of the curve and / or adjacent to the most proximal edge of the clot. To allow visualization of distal tip placement, a radiopaque marker 40 is placed on the visual tip.

[0122] In some cases, the physician may not be fully aware of the position of the distal tip relative to the vessel, and the rotational movement of the beveled tip under suction pressure may cause the most favorable orientation of the tip within the vessel, resulting in sudden ingestion of the clot.

[0123] (Further distal procedures) In another embodiment, a method for enhancing the capture of a stuck clot is described. In one example, after attempting to aspirate a clot with a G2BA, the clot may become stuck at the distal tip. The physician may choose to remove the G2BA, hoping that the clot will not fragment and / or result in distal embolization when the G2BA is removed. As shown in FIG. 6A , one solution the G2BA offers is the option to run an additional aspiration catheter AC through the G2BA 10 to reach the distal tip of the G2BA and the stuck clot (while maintaining negative / aspiration pressure through a small AC to hold the stuck clot). In a typical G2BA placement, the G2BA is an 8F catheter, so approximately a 6F AC can be run over the G2BA. Preferably, the 6F catheter is designed to prevent the catheter from protruding from the G2BA, thus preventing the clot stuck at the tip from accidentally becoming dislodged. Importantly, as shown in FIG. 6A , by placing the 6F AC on the cork, a substantially greater suction force P5 can be applied through the 6F AC. Applying higher suction pressure at the center of the clot allows the smaller catheter to increase its ability to aspirate. Furthermore, even if the smaller catheter is unable to aspirate, the additional suction force can hold it firmly at its tip, facilitating the process of ingesting the entire clot into the larger catheter as the 6F catheter is removed. Thus, application of this additional suction pressure and removal of the 6F AC allows the clot to loosen into the 8F G2BA, allowing it to be subsequently removed through the entire passageway within the G2BA or the entire assembly to be removed. In one embodiment, if a clot becomes lodged within the G2BA during aspiration, the AC can be advanced within the G2BA to apply suction pressure to potentially dislodge and / or assist in extracting the clot without losing its position.

[0124] In a further embodiment, after aspiration of the clot, standard procedure is to perform a check angiogram to determine whether the entire clot has been removed. In some cases, fragments of the clot may embolize and migrate distally as detected by the check angiogram. In this case, a secondary distal procedure may be performed.

[0125] For example, as shown in Figures 3A and 6B, if a check angiogram performed with the G2BA in place while aspirating clot Y from the M1 segment via an 8F catheter 10 determines that a small embolus Y1 has detached and lodged distally within the M3 segment, the physician may decide to perform an alternative secondary distal procedure following the following steps. a) While holding the first G2BA 10 in place, a second, longer G2BA 11 (having an outer diameter of approximately 5F) is advanced through the first G2BA along with the second ISC (and second MW; 11a FIG. 3A). The second G2BA 11 is sized to move coaxially within the first G2BA, initially advancing to the distal tip of the first G2BA. b) The second MW and second ISC are advanced beyond the distal tip of the first G2BA by selective manipulation of the second ISC, second MW and second G2BA until they reach the proximal face of the embolus Y1. c) Removing the second ISC and the second MW. d) Apply suction P6 to the second G2BA via the pump to aspirate the embolus into the second G2BA. If suction is unsuccessful and blood does not return, a clot may be engaged at the distal end but not aspirated into the second G2BA. In this case, the second G2BA (together with the engaged clot fragment Y1) can be pulled into the first G2BA and removed through the first G2BA. e) Perform a check angiogram. f) If clear, remove the first G2BA (and the second G2BA if still in place). g) If not clear, further options can be evaluated.

[0126] G2BA can also be used in pediatric cases, in which case an appropriately small G2BA catheter is used based on the relative height / size of the patient.

[0127] (lower stenosis) Another application may require periodic removal of clots and stenting of lower stenoses simultaneously. Stents may be required for tight stenoses in the carotid artery or intracranial vessels. Because stents are relatively stiff, pushing these stents around curves and tortuosity in the vessels can be problematic. Also, if the outer diameter of the stent is larger than a conventional aspiration catheter or guide sheath, these must be removed to allow for larger systems. Therefore, the use of a G2BA in these procedures is advantageous. In this case, a stent with a longer push wire is required to be able to pass through the G2BA. This means that current stents require a longer push wire to be deployed through a longer G2BA catheter.

[0128] (radial artery access) As mentioned above, the DEP can be the radial artery. Accessing the carotid artery from the radial artery requires moving through the radial artery and brachial artery to the aortic arch, which typically requires rotating the DC / GW 180° to hook the desired carotid artery. Therefore, the G2BA offers advantages over conventional AC / GC systems because the distal section of the G2BA can easily ride over the GW / DC and make sharp turns in the aortic arch.

[0129] (brain cooling) Cooling the brain is known to have a neuroprotective effect when the brain is deprived of oxygen. In the case of cerebral infarction, brain cooling has been considered before or after clot removal. Cooling the patient's entire body is generally complicated because it requires general anesthetics and muscle relaxants due to the effects of shivering. Therefore, attempts have been made to directly cool the brain by introducing chilled fluid into the brain through the catheter using the same catheter system after clot removal. However, direct introduction of cold fluid (typically cold saline) into the brain through the catheter has been unsuccessful because the cold fluid cannot be adequately insulated from the warm body during its journey to the brain. For example, 6F catheters used as aspiration catheters do not provide sufficient insulation to deliver cooled fluid directly to the brain, and therefore, additional insulation is required for effectiveness. However, 6F catheters can only deliver approximately 4F catheters with a 2F lumen for delivering the cooled fluid. Given the length of a typical aspiration catheter, by the time the cold fluid (e.g., introduced at approximately 1°C) travels the length of the catheter, there is still insufficient insulation to achieve an effective cooling effect. This means that the injected fluid may be above 15°C when it leaves the catheter, which is insufficient to provide effective cooling. Furthermore, there is a limit to the amount of fluid that can be introduced, and introducing larger volumes of fluid cannot solve this problem, as an increase in fluid volume can cause other effects, including pulmonary edema.

[0130] Furthermore, adding insulation to the catheter wall changes its properties, making it stiffer. Such insulated catheters generally cannot navigate around the various curves required to reach the cerebral vasculature when pushed through a 6F catheter. Also, because the insulation takes up space, the lumen is quite small, and therefore does not provide space for an ISC to facilitate negotiating curves.

[0131] Attempts have been made to design catheters in which the distal 15 cm is thinner and uninsulated, but the proximal section is insulated to overcome the stiffness issue. However, even in this case, there is a substantial loss of cooling efficiency due to heating of the cold saline solution in the last 15 cm. However, as the G2BA catheter becomes larger in the brain, more volume is available for insulation. Furthermore, insulation can be carried all the way to the tip of the cooling catheter. This is because the cooling catheter has a larger travel distance and can incorporate flexibility into the distal section, improving insulation. For example, after an 8F G2BA catheter is placed in the M1 segment of the MCA and used to aspirate the clot, an insulated 6F catheter with a larger insulating wall is inserted into the G2BA and run to the distal tip of the G2BA. Due to the high insulation, fluid introduced at 1–3°C may emerge at a temperature of 2–8°C, sufficient for effective brain cooling.

[0132] The insulated catheter is substantially the same length (nominal longer) as the G2BA catheter and is sized to fit within the G2BA. As shown schematically in Figure 6C, an 8F G2BA 10 has an outer diameter of 0.105 inches and a typical wall thickness of 0.013 inches, allowing a 6F insulated catheter 13 to move within it. The insulated catheter has an outer diameter of 0.079 inches and can have a wall thickness in the 0.026 inch range, thus providing a lumen of 0.027 inches. The thicker wall provides enough additional insulation to transport the cold fluid to the distal tip of the G2BA and into the cerebral circulation. A lumen size of 1.5F is the approximate minimum lumen size for transporting a sufficient volume of fluid.

[0133] In one embodiment, a fluid cooling module is utilized to deliver cooled liquid to the proximal end of the cooling catheter. Generally, the fluid cooling module includes a fluid pump and a controller for pumping a calculated amount of cooled liquid through the cooling catheter. The calculated amount is determined based on modeling of heat transfer through the cooling catheter, modeling data for the D2BA catheter selected for the patient, patient data, and the desired cooled liquid temperature at the distal end of the cooling catheter.

[0134] In one embodiment, the ISC is also used as a cooling catheter, referred to as an integrated support and cooling catheter (ISCC). In this case, an ISCC with proximal insulation would be used to advance the G2BA catheter. After removal and aspiration, the ISCC is reintroduced to introduce a flow of cooling fluid. Similar to the ISC, the ISCC includes a tapered distal zone to support the distal tip of the G2BA as it passes through the tortuous parts of the patient's cerebral vasculature, and an insulating proximal zone that can introduce cooling fluid to the proximal end of the ISCC. In terms of performance, cooling fluid introduced at 1–3°C into the proximal end is discharged at 2–8°C from the ISCC.

[0135] (Suction and suction pulse) Once the G2BA is in place, other procedures and devices can be employed to improve suction efficiency.

[0136] The application of suction pulses can also be used to improve engagement of the G2BA with the clot. Because a tight seal with the vessel wall is likely, a short pressure pulse or pulses may bring the G2BA or clot closer together, resulting in more rapid engagement and / or ingestion, thus potentially eliminating the need to wait for a period of time for engagement between the catheter and the clot. For example, the application of one to three short, low-pressure pulses followed by a larger pressure pulse may result in successive alignment or partial ingestion of the clot, followed by a higher pressure pulse that completely ingestes the clot.

[0137] Additionally, measurements of pressure waves at the pump can be used to quantify the effectiveness of the aspiration process by comparing the applied pressure waves with the measured response at the pump. Analysis of the response can be used to dynamically adjust the pressure delivered. That is, pressure waves are generated by the pump and measurements of the pressure / flow waveform received back from the G2BA can be compared to determine the effectiveness of the aspiration pressure at the seat of the G2BA on aspiration of the clot and / or clots.

[0138] The pressure waveform can also compensate for the compliance of the G2BA.

[0139] In further embodiments, the suction pump can be wifi enabled, thus capturing suction pulse data and using that data through machine learning and artificial intelligence based algorithms to improve pressure pulses, and using information gained from the first pressure pulse to improve subsequent pressure pulses based on AI algorithms developed from a continuously growing database of past performance.

[0140] Additionally, the suction pressure of the suction pump may be higher with larger diameter G2BAs.

[0141] Preferably, the aspiration pump includes a filter that captures any aspirated clots. Visual inspection of the aspiration pump for clots, together with or separate from flow data through the G2BA, can provide useful information as to whether circulation has been established and whether the procedure was successful.

[0142] The pulse pressure algorithm can also be applied to the more distal procedures described above.

[0143] (G2BA kit) A variety of kits may be provided, as summarized in Table 5, where the kits are assembled based on target level (referred to here as Levels 1-4, with Level 1 being deeper (e.g., Level 2 segments) and Level 4 being lower in the vasculature). Table 5: G2BA / DC and ISC kits [Table 5]

[0144] Typically, the surgeon selects a kit based on their understanding of the vessel diameter at the target level and clot. Additionally, kits may be provided with specific DC / GW combinations selected based on the surgeon's diagnostic evaluation of the patient's aortic arch. Table 5 presents DCs with generic placeholders A, B, and C, each with specific tip / hardness / shape characteristics.

[0145] Due to the significant cost difference between DC and ISC and G2BA, kits may contain multiple DCs.

[0146] Further alternative kits are described below. a) A kit containing a second G2BA, ISC, and MW of appropriate diameter to be used in combination with or included in a kit shown in Table 5 to perform a secondary distal procedure. b) The kit shown in Table 5 with the addition of an AC sized to fit within the G2BA, the AC being long enough to not extend beyond the distal tip of the G2BA. c) Any of the above kits together with a cooling catheter.

[0147] (Summary of benefits) The use of G2BA and its deployment method in conjunction with ISC provides the following advantages, among others: a) Fewer catheters (no GC or BGC is important). b) Fewer steps, faster. c) The catheter becomes larger. d) Able to move forward through difficult sections. e) It is easier to align the tip when applying suction. f) There is less chance of air bubbles getting into the circulatory system because insufficiently cleaned catheters are used less often. g) It may reduce the need for larger groin sheaths. h) Reduced procedural costs, especially since the need for a stent retriever may be eliminated. i) Improve reperfusion rates and patient outcomes. j) Reducing the possibility of operating room delays due to coronavirus by reducing the handover of equipment from person to person. k) Improving the speed of procedures performed using stiffer DCs by providing a softer G2BA distal zone that can ride on top of stiffer DCs, which may encourage surgeons to select a more suitable DC to engage the origin of the appropriate carotid artery. l) The clot can be completely ingested, reducing the chances of clot fragmentation. m) Overall improvement in the ability to aspirate non-homogeneous clots. Some clots have different compositions and can fragment between regions of different composition. The size of the aspiration catheter is closer to the clot (and blood vessel), greatly increasing the chances of aspirating the clot. The entire clot is more likely to be sealed, allowing for stronger pulse pressure to be applied, resulting in more effective ingestion of fibrous and non-fibrous clots. n) Use secondary G2BA and ISC to access secondary distal emboli and improve the rate of distal emboli removal. o) Reduces the likelihood of secondary distal embolization. p) Improved access from the radial artery. q) Facilitating access to rigid stent systems in cases of intracranial or carotid atherosclerosis. r) In the case of ischemic areas, it facilitates access to an insulated catheter for supplying cooling fluid for local hypothermia.

[0148] From the above, it is important to note that the structural and functional characteristics of D2BA catheters distinguish them from those of other catheters. That is, while catheters capable of performing aspiration functions and catheters with various physical sizes and stiffnesses may appear similar, the differences in the combination of size, length, and performance characteristics are significant in that the combination of physical and functional properties enables the implementation of new procedures that provide real benefits to patients. Furthermore, because a wide range of manufacturing techniques and materials can be combined in various ways to provide catheters with unique combinations of physical and functional properties, it is important to understand the need to balance the specific mechanical and chemical properties of the materials used in catheter construction to provide the desired final functional capabilities.

Claims

1. 1. A Distal Entry Point (DEP) to Cerebral Aspiration (D2BA) catheter for use in an endovascular procedure to gain access to the carotid arteries and cerebral arteries of a patient's brain and to aspirate one or more intracranial blood clots from the cerebral arteries, the D2BA catheter for placement in the patient's human blood vessels between the DEP and the cerebral arteries of the brain comprising: a soft distal tip region having a distal length sufficient to extend from a level 1 or level 2 arterial segment of a cerebral artery or equivalent to a superior carotid vessel, the soft distal tip region having a stiffness that allows movement through the level 1 or level 2 arterial segment of the cerebral artery and an outer diameter (OD) of 6F to 10F; a proximal region having a hardness greater than the hardness of the soft distal tip region, the proximal region having a length sufficient to extend through the DEP to the outside of the patient; Equipped with The D2BA catheter allows for suction through the D2BA catheter to remove the one or more blood clots.

2. 2. The D2BA catheter of claim 1, wherein the soft distal tip region and the proximal region have sufficient flexibility and axial and radial compressive stiffness to allow the soft distal tip region to be advanced over a guidewire (GW) and diagnostic catheter (DC) and to position the distal tip of the soft distal tip region near the upper neck / base of the skull without an external supporting catheter.

3. 3. A D2BA catheter as described in claim 1 or claim 2, wherein the soft distal tip region and the proximal region have sufficient flexibility and axial and radial compressive stiffness, so that when the soft distal tip region is advanced over a guidewire (GW) and a diagnostic catheter (DC) and positioned near the upper neck / base of the skull, the D2BA catheter will not come out of the carotid artery even when the guidewire and the diagnostic catheter are removed.

4. 4. The D2BA catheter of claim 1, wherein the soft distal tip region and the proximal region have sufficient flexibility and axial and radial compressive stiffness such that when the GW and DC are removed, a microwire (MW) and an integrated support catheter (ISC) can be advanced through the D2BA catheter to the distal tip, and the D2BA is further advanced over the MW and ISC until the distal tip substantially engages the cerebral artery wall adjacent a blood clot.

5. 10. The D2BA catheter of claim 1, wherein the D2BA catheter has a wall thickness of 0.013 inches or less.

6. 6. The D2BA catheter of claim 1, wherein the outer diameter (OD) of the D2BA catheter is 7F and the distal length extends from the superior carotid vessel to the middle cerebral artery level 2 segment, or from the distal cervical artery to the basilar artery or equivalent.

7. The D2BA catheter of claim 6, wherein the distal length is 17 to 25 cm.

8. 6. The D2BA catheter of claim 1, wherein the outer diameter (OD) of the D2BA catheter is 8F and the distal length extends from the superior carotid vessel to the distal level 1 segment of the middle cerebral artery.

9. The D2BA catheter of claim 8, wherein the distal length is 15 to 23 cm.

10. 6. The D2BA catheter of claim 1, wherein the outer diameter (OD) of the D2BA catheter is 9F and the distal length extends from the superior carotid artery to the proximal level 1 segment of the middle cerebral artery or equivalent.

11. The D2BA catheter of claim 10, wherein the distal length is 13 to 21 cm.

12. 6. The D2BA catheter of claim 1, wherein the outer diameter (OD) of the D2BA catheter is 10F and the distal length extends from the superior carotid artery to the distal segment of the internal carotid artery or equivalent.

13. The D2BA catheter of claim 12, wherein the distal length is 12 to 16 cm.

14. the soft distal tip region comprises at least one polymer section having a composition that provides axial stiffness and flexibility for a particular linear position of the D2BA catheter; the proximal region comprises at least one polymer section having a composition that provides axial stiffness and flexibility for a particular linear position of the D2BA catheter; A D2BA catheter according to any one of claims 1 to 13.

15. 15. The D2BA catheter of claim 1, wherein the D2BA catheter has a torsional stiffness such that torque applied to the proximal zone is transmitted to the distal tip of the distal zone, allowing rotational movement of the distal tip within the blood vessel, and the distal tip defines an oblique angle in the range of 10 to 30 degrees relative to a vertical cross section of the D2BA catheter.

16. A D2BA catheter according to any one of claims 1 to 15; a second aspiration catheter having an outer diameter maximized to operate within the D2BA catheter and a length sufficient to extend to a position substantially equivalent to the distal tip of the D2BA catheter, the second aspiration catheter being configured to be positioned adjacent to the distal tip of the D2BA catheter and to apply aspiration pressure to the proximal edge of the clot via the second aspiration catheter while within the D2BA catheter; An intravascular catheter system comprising:

17. 17. The intravascular catheter system of claim 16, wherein the second suction catheter has a proximal end and a proximal end lock, the proximal end lock engageable with a proximal region of the D2BA catheter to prevent the second suction catheter from extending beyond the distal tip of the D2BA catheter.

18. A D2BA catheter according to any one of claims 1 to 15; a cooling catheter having an outer diameter maximized to operate within the D2BA catheter and a length sufficient to extend to a position substantially equivalent to the distal tip of the D2BA catheter, the cooling catheter configured to deliver cooling fluid through the cooling catheter to the distal tip of the D2BA catheter; wherein the combination of the D2BA catheter and the cooling catheter provides sufficient insulation to allow effective flow of cooling fluid through the insulated catheter to effectively cool brain tissue after clot removal.

19. 19. The intravascular catheter system of claim 18, wherein the D2BA catheter has an outer diameter (OD) of 8F, the cooling catheter has an outer diameter (OD) of substantially 6F, and the cooling catheter has a wall thickness of 0.020 to 0.03 inches, preferably 0.026 inches.

20. 20. The intravascular catheter system of claim 19, wherein the wall thickness of the cooling catheter is substantially constant along the length of the cooling catheter and includes thermal insulation to the distal tip of the cooling catheter.

21. A D2BA catheter according to any one of claims 1 to 15; a secondary D2BA catheter having an outer diameter maximized to operate within the D2BA catheter and a length sufficient to extend beyond the distal tip of the D2BA catheter, the secondary D2BA catheter configured to allow advancement of the secondary D2BA catheter beyond the distal tip of the D2BA catheter and to apply suction pressure to a proximal edge of a secondary clot distal to the clot via the secondary D2BA catheter; An intravascular catheter system comprising:

22. A D2BA catheter according to any one of claims 1 to 15; a diagnostic catheter (DC) and guidewire (GW) for internally assisting the advancement of the D2BA catheter into the carotid artery; an integrated support catheter (ISC) having an outer diameter maximized to operate within the D2BA catheter, a length sufficient to extend beyond the distal tip of the D2BA catheter, and a distal taper to support the distal tip of the D2BA catheter during advancement of the D2BA catheter into a cerebral artery; a microwire (MW) configured for operation within the ISC and having a length sufficient to extend beyond the distal tip of the ISC to advance the ISC and the D2BA catheter into a cerebral artery; a secondary D2BA catheter having an outer diameter maximized to operate within the D2BA catheter and a length sufficient to extend beyond the distal tip of the D2BA catheter, the secondary D2BA catheter configured to allow advancement of the secondary D2BA catheter beyond the distal tip of the D2BA catheter and to apply suction pressure to a proximal edge of a secondary clot distal to the clot via the secondary D2BA catheter; a secondary integrated support catheter (ISC) having an outer diameter maximized to operate within the secondary D2BA catheter and a length sufficient to extend beyond the distal tip of the secondary D2BA catheter; a secondary microwire (MW) configured for operation within the secondary ISC and having a length sufficient to extend beyond the distal tip of the secondary ISC; An intravascular catheter system comprising:

23. A D2BA catheter according to any one of claims 1 to 15; a stent configured for operation within the D2BA catheter, the stent being operably connected to a pusher wire having a length sufficient to extend beyond the distal tip of the D2BA catheter to enable deployment of the stent from the distal tip of the D2BA catheter; An intravascular catheter system comprising:

24. 1. A kit for use in an endovascular procedure for accessing cervical and cerebral arteries and aspirating intracranial blood clots from said cerebral arteries, comprising: an intravascular catheter comprising a D2BA catheter according to any one of claims 1 to 15 for placement in the human vasculature between a distal entry point (DEP) and a cerebral artery; at least one diagnostic catheter (DC), each DC having an outer diameter that fits and slides within said D2BA catheter, each DC having a pre-formed tip for accessing various anatomical structures of the aortic arch, and each DC having a length longer than said D2BA catheter; A guide wire (GW) having a diameter that fits and slides within the DC and a length that is longer than the DC; A kit comprising:

25. 25. The kit of claim 24, further comprising an internal support catheter (ISC), the ISC having an outer diameter that fits and slides within the D2BA catheter and a tapered distal zone for supporting and transitioning the distal tip of the D2BA catheter within tightly curved arteries during advancement of the D2BA catheter into a cerebral artery.

26. 25. The kit of claim 24, comprising two or more DCs.

27. The kit of any one of claims 24 to 26, further comprising an aspiration catheter having an outer diameter maximized to operate within the D2BA catheter and a length sufficient to extend to a position substantially equivalent to the distal tip of the D2BA catheter.

28. The kit of any one of claims 24 to 27, further comprising a cooling catheter having an outer diameter maximized to operate within the D2BA catheter and a length sufficient to extend to a position substantially equivalent to the distal tip of the D2BA catheter.

29. 25. The kit of claim 24, further comprising a second D2BA catheter sized to fit within the D2BA catheter, and a corresponding second ISC and second MW, each having a length greater than the D2BA catheter and sized to fit within the second D2BA catheter.

30. 1. A cooling catheter for delivering an effective amount of cooling fluid through a D2BA catheter, the cooling catheter having an outer diameter maximized to operate within the D2BA catheter and a length sufficient to extend to a position substantially equivalent to a distal tip of the D2BA catheter, the cooling catheter being configured to deliver cooling fluid through the cooling catheter to the distal tip of the D2BA catheter, the combination of the D2BA catheter and the cooling catheter providing sufficient insulation to allow effective flow of cooling fluid through the insulated catheter to effectively cool brain tissue after clot removal.

31. 31. The cooling catheter of claim 30, wherein the wall thickness of the cooling catheter is substantially constant along the length of the cooling catheter and includes thermal insulation to the distal tip of the cooling catheter.

32. An endovascular method for gaining access to carotid and cerebral arteries includes placing a catheter system within the human vasculature between a distal entry point (DEP) and a cerebral artery, and aspirating a cerebral clot in one of the cerebral arteries, the endovascular method comprising: a) introducing a catheter system comprising a D2BA catheter according to any one of claims 1 to 15, a guidewire (GW) and a diagnostic catheter (DC) via a DEP; b) advancing the catheter system into the aortic arch; c) advancing the GW and the DC to a desired carotid artery and maneuvering the GW into the desired carotid artery; d) advancing the D2BA catheter to the desired carotid artery above the DC and GW; e) removing the DC and the GW; f) introducing an inner support catheter (ISC) having a tapered distal section for supporting the distal end of the D2BA catheter and adapted to facilitate movement of the distal end through tight curves in the cerebral vasculature, and an ISC microwire (ISC MW); g) advancing the ISC and the ISC MW into the cerebral artery containing the clot; h) advancing the D2BA catheter to the proximal aspect of the clot and removing the ISC and the ISC MW; i) applying suction of the clot via the D2BA catheter; A method comprising:

33. j) after applying suction to dislodge the clot in step i, performing a check angiogram to determine whether the entire clot has been dislodged and whether one or more distal emboli are present; and if one or more distal emboli are present, k) advancing a second D2BA catheter sized for coaxial movement within said D2BA catheter along with a second ISC and a second ISC MW to a proximal aspect of said distal embolism; l) applying suction to the second D2BA catheter and removing the distal embolus by suction or by removing the second D2BA catheter; 33. The method of claim 32, further comprising:

34. 33. The method of claim 32, wherein the DEP is the radial artery and the D2BA catheter has a proximal length adapted for advancement from a radial artery puncture.

35. 33. The method of claim 32, wherein the DEP is the femoral artery and the D2BA catheter has a proximal length adapted for advancement from a femoral artery puncture.

36. 33. The method of claim 32, wherein step i comprises applying one or more first pressure pulses through the D2BA catheter to assist in engaging the distal tip of the D2BA catheter with the clot, and then applying at least one second suction pulse to aspirate the clot.

37. 33. The method of claim 32, further comprising the step of comparing a predetermined pressure pulse to a measured response pressure at the aspiration pump and adjusting subsequent pressure pulses based on the measured response pressure.

38. 38. The method of claim 37, wherein the step of adjusting subsequent pressure pulses takes into account pressure response data from multiple patients collected and analyzed from similar procedures.

39. 33. The method of claim 32, wherein suction is performed via a suction pump operatively connected to the Internet and a central analysis computer system, wherein pressure response data from different pumps is received and analyzed by the central computer system, and pump pressure algorithms are updated to the different pumps via the Internet.

40. 40. The method of claim 39, wherein the pump pressure algorithm takes into account catheter material, brand and / or size.

41. 33. The method of claim 32, further comprising the steps of: if suction fails, introducing a suction catheter into the D2BA catheter, advancing the suction catheter to the distal tip of the D2BA catheter, and applying suction through the D2BA catheter.

42. 33. The method of claim 32, further comprising the steps of, if aspiration is successful, introducing a cooling catheter into the D2BA catheter, advancing the cooling catheter to the distal tip of the D2BA catheter, and flowing a cooling fluid through the cooling catheter to cool brain tissue.

43. 43. The method of claim 42, further comprising flowing brain nutrient fluid through the cooling catheter.

44. 43. The method of claim 42, wherein the cooling catheter is an ISC with proximal insulation, and after the ISC is removed and suction is completed, the ISC is reintroduced and brain nutrient fluid is flowed through the ISC.

45. A method for effectively removing foreign blood clots having fibrin-rich regions and red blood cell-rich regions from cerebral blood vessels, comprising: a) positioning a D2BA catheter according to any one of claims 1 to 15 adjacent to the proximal edge of a blood clot in the cerebral vessel; b) applying a first pressure pulse to effect suction of a first proximal region of the clot; c) applying a second pressure pulse to effect suction of a second distal region of the clot; A method comprising:

46. 46. ​​The method of claim 45, wherein the first proximal region is a fibrin-rich region and the second distal region is a red blood cell-rich region.

47. 47. The method of claim 46, further comprising monitoring a first return pressure wave after delivery of the first pressure pulse and adjusting the second pressure pulse based on the first return pressure wave.

48. 1. A cooling device for controlling the temperature of a cooling fluid delivered through a cooling catheter, the cooling device comprising: a fluid cooling module for supplying cooling liquid to a proximal end of the cooling catheter, the fluid cooling module comprising:

16. A cooling device comprising a fluid pump and a controller for pumping a calculated amount of coolant through the cooling catheter, the calculated amount being based on modeling of heat transfer through the cooling catheter, modeling data of a D2BA catheter described in any one of claims 1 to 15 selected for a patient, patient data, and a desired coolant temperature at the distal end of the cooling catheter.

49. 16. Use of a D2BA catheter according to any one of claims 1 to 15 for accessing a cerebral artery without the support of a guide catheter and applying suction to one or more intracranial blood clots from said cerebral artery, wherein said D2BA catheter is for placement in the human vasculature between a distal entry point (DEP) and a cerebral artery, said D2BA catheter comprising: a soft distal tip region having a distal length sufficient to extend from a level 1 or level 2 arterial segment or equivalent to an arterial vessel near the upper cervical / base of the skull, the soft distal tip region having an outer diameter (OD) of 6F to 10F; a proximal region connected to the soft distal tip region at a junction, the proximal region having a length sufficient to extend through the DEP to the exterior of the patient and having an outer diameter substantially similar to an inner diameter of the soft distal tip region; Equipped with The D2BA catheter allows for suction through the D2BA catheter to remove the one or more blood clots.

50. 50. The use of claim 49, wherein the soft distal tip region and the proximal region have sufficient balanced flexibility and axial and radial compressive stiffness to allow the soft distal tip region to be advanced over a guidewire (GW) and diagnostic catheter (DC) and to position the distal tip of the soft distal tip region near the upper neck / base of the skull without an external supporting catheter.

51. 51. The intravascular catheter of claim 49 or 50, wherein the soft distal tip region and the proximal region have sufficient balanced flexibility and axial and radial compressive stiffness, so that when the soft distal tip region is advanced over a guidewire (GW) and a diagnostic catheter (DC) and positioned near the upper neck / base of the skull, the D2BA catheter will not come out of the carotid artery even if the guidewire and the diagnostic catheter are removed.

52. 52. The use of any one of claims 49 to 51, wherein the soft distal tip region and the proximal region have sufficient flexibility and axial and radial compressive stiffness balanced with each other, and when the GW and DC are removed, a microwire (MW) and an integrated support catheter (ISC) can be advanced to the distal tip through the D2BA catheter, and the D2BA catheter is further advanced over the MW and ISC until the distal tip substantially engages the cerebral artery wall adjacent a blood clot.

53. 1. An intravascular catheter for use in an intravascular procedure, the intravascular catheter having a structure for gaining access to a carotid artery and a cerebral artery and for aspirating one or more intracranial blood clots from a cerebral artery, the intravascular catheter being for placement within the human vasculature between a distal entry point (DEP) and a cerebral artery, the catheter comprising: a soft distal tip region having a distal length sufficient to extend from a level 1 or level 2 arterial segment of a cerebral artery or equivalent to an arterial vessel near the upper cervical / base of the skull, the soft distal tip region having an outer diameter (OD) of 6F to 10F, the soft distal tip region being flexible enough to ride over a diagnostic catheter (DC) and guidewire (GW) placed in the carotid artery and access the carotid artery through the aortic arch without causing prolapse of the DC and GW, and allowing the D2BA catheter to be further advanced into a cerebral artery upon removal of the DC and GW; a proximal region transitioning to the soft distal tip region, the proximal region having a length sufficient to extend through the DEP to the exterior of the patient; The D2BA catheter is an intravascular catheter that can be advanced to the carotid artery without the support of a guide catheter.

54. 1. A distal entry point to brain aspiration (D2BA) catheter having an outer diameter greater than 6F and a length sufficient to extend from a distal entry point (DEP) outside the body to a blood clot in a level 1 or level 2 segment of a cerebral artery, wherein the D2BA catheter has sufficient axial flexibility / rigidity along its length to be advanced from the DEP to the distal tips of the GW and DC over a guidewire (GW) and a diagnostic catheter (DC) when the GW and DC are positioned at a level proximal to the upper neck / skull base, and wherein the D2BA catheter can be advanced through the aortic arch supported only by the GW and DC.

55. 55. The D2BA catheter of claim 54, wherein the DEP is the radial artery.

56. 55. The D2BA catheter of claim 54, wherein the DEP is the femoral artery.

57. 1. A Distal Entry Point to Brain Aspiration (D2BA) catheter comprising a catheter, the catheter comprising: Outer diameter of 6F to 10F, a length sufficient to extend from a distal entry point (DEP) outside the body to the cerebral artery clot; and a soft distal tip zone having axial flexibility / stiffness along its length for advancing the D2BA catheter over a guidewire (GW) and a diagnostic catheter (DC) from the DEP to the distal tips of the GW and the DC when the GW and the DC are located at an upper cervical / proximal skull base level, the soft distal tip zone having a distal tip outer diameter selected to substantially match the inner diameter of the artery in which the clot is located and a length extending from the clot to an upper cervical / proximal skull base level. a proximal zone having axial flexibility / stiffness along its length for advancing the D2BA catheter, allowing the soft distal tip zone to be advanced through the aortic arch with only support from the GW and the DC.

58. 1. An aspiration catheter (AC) having an outer diameter greater than 6F and a length sufficient to extend from a distal entry point (DEP) to an arterial segment at or above level 1 of the brain, said AC having a distal region and a proximal region, and having a combination of axial flexibility and stiffness, The AC is advanced over a diagnostic catheter (DC) and a guidewire (GW) placed between the DEP and the carotid artery without the DC and the GW protruding and without the support of a guide catheter (GC); The DC and the GW remove the AC without escaping the AC; advancing the AC together with at least one microcatheter (MC) and microwire (MW) to a clot in an arterial segment at level 1 or above; applying suction from the AC to aspirate the clot; This is possible with an AC catheter.

59. 1. An aspiration catheter (AC) comprising a catheter having an outer diameter of 6F to 10F and a length sufficient to extend from a distal entry point (DEP) to a blood clot in a cerebral artery, said AC having a distal region with a distal tip having a distal tip outer diameter substantially corresponding to the inner diameter of the cerebral artery in which said blood clot is located and a length extending from said blood clot to near the upper neck / base of the skull, said distal and proximal regions having a combination of axial flexibility and stiffness; The AC is advanced over a diagnostic catheter (DC) and a guidewire (GW) disposed between the DEP and the carotid artery without the DC and the GW protruding and without the support of a guide catheter (GC); The DC and the GW remove the AC without escaping the AC; advancing the AC together with at least one microcatheter (MC) or integrated support catheter (ISC) and a microwire (MW) to the clot in an arterial segment at level 1 or above; An AC catheter, wherein the distal tip is proximate to the clot and capable of drawing suction from the AC to aspirate the clot.

60. 16. An integrated support and cooling catheter (ISCC) for assisting in the advancement of a D2BA catheter as described in any one of claims 1 to 15, wherein the ISCC allows for the flow of coolant through the ISCC after aspiration of a blood clot through the D2BA, the ISCC comprising a catheter having a tapered distal zone for supporting the distal tip of the D2BA as it passes through tortuous sections of a patient's cerebral vasculature, and an insulated proximal zone that allows coolant to be introduced into the proximal end of the ISCC at 1-3°C and for the coolant to exit the ISCC at 2-8°C.

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