Devices and methods for accessing neurovascular sites

Abstract

A neurovascular catheter for insertion into a patient's internal carotid artery is disclosed. The neurovascular catheter includes a flexible distal segment for insertion into the patient's internal carotid artery. The flexible distal segment may include a distal portion, a transition portion, and a support portion. The distal portion includes a tracking tip configured to be positioned within the cavernous segment of the internal carotid artery and a stiffening portion. The transition portion may be positioned within the pyramidal segment of the internal carotid artery. The support portion may extend proximal to the base of the patient's skull.

Description

Technical Field

[0001] Priority Information This application claims the benefit of priority of U.S. Provisional Application No. 63 / 472,244, filed on June 9, 2023, the entire content of which is incorporated herein by reference.

Background Art

[0002] Stroke is the third leading cause of death in the United States and the most disabling neurological disorder. Approximately 700,000 patients suffer from stroke every year. Stroke is a syndrome characterized by the acute onset of neurological deficits that persist for at least 24 hours, reflecting a focal involvement of the central nervous system and resulting from a disruption of cerebral circulation. Its incidence increases with age. Risk factors for stroke include systolic or diastolic hypertension, hypercholesterolemia, smoking, heavy alcohol consumption, and the use of oral contraceptives.

[0003]

[0004] Embolisms may form around the heart valves or in the left atrial appendage during periods of irregular heart rhythm, and then the emboli move and follow the blood flow to distal regions of the body. These emboli can move to the brain and cause embolic stroke. As will be described later, many such occlusions occur in the middle cerebral artery (MCA), but this is not the only site where the emboli lodge. Hemorrhagic stroke accounts for 20% of the annual stroke population. Hemorrhagic stroke is caused by the rupture of an aneurysm or bleeding from an arteriovenous malformation into the brain tissue, often resulting in a cerebral infarction. The remaining 80% of the stroke population is ischemic stroke, caused by an "occluded blood vessel" that deprives the brain of oxygen-carrying blood. Ischemic stroke is often caused by emboli or thrombotic tissue fragments that are dislodged from other body sites or from the cerebral blood vessels themselves and occlude more distal, narrow cerebral arteries. When a patient exhibits neurological symptoms and signs that completely resolve within one hour, the term transient ischemic attack (TIA) is used. Etiologically, TIA and stroke share the same pathophysiological mechanisms and thus represent a continuum based on the duration of symptoms and the extent of ischemic injury.

[0005] If a patient presents with neurological deficits, a diagnostic hypothesis regarding the cause of stroke can be generated based on the patient's medical history, a review of stroke risk factors, and neurological examination. If an ischemic event is suspected, the clinician may tentatively assess whether the patient has a cardiogenic source of embolus, extracranial or intracranial aortic disease, intraparenchymal disease of the arterioles, or hematological or other systemic disorders. Head CT scans are often performed to determine whether the patient has suffered an ischemic or hemorrhagic injury. Blood may be present on a CT scan in cases of subarachnoid hemorrhage, intraparenchymal hematoma, or intraventricular hemorrhage.

[0006] Traditionally, emergency management of acute ischemic stroke consisted primarily of general supportive care, such as hydration, monitoring of neurological status, blood pressure control, and / or antiplatelet or anticoagulant therapy. In 1996, the Food and Drug Administration approved the use of Genentech Inc.'s thrombolytic agent, tissue plasminogen activator (t-PA), or Activase®, for the treatment of acute stroke. A national randomized, double-blind trial of neurological impairment and t-PA stroke studies revealed a statistically significant improvement in Stork Scale scores at 24 hours in patients who received intravenous t-PA within 3 hours of ischemic stroke onset. The approval of t-PA enabled emergency room physicians to provide stroke patients with an effective treatment option beyond supportive care for the first time.

[0007] However, treatment with systemic t-PA is associated with an increased risk of intracerebral hemorrhage and other hemorrhagic complications. Patients treated with t-PA were more likely to develop symptomatic intracerebral hemorrhage within the first 36 hours of treatment. Administering t-PA more than 3 hours after stroke onset increases the frequency of symptomatic bleeding. In addition to the time constraints for using t-PA in acute ischemic stroke, other contraindications include: if the patient has experienced a stroke or severe head injury in the past 3 months; if the patient has a systolic blood pressure greater than 185 mmHg or a diastolic blood pressure greater than 110 mmHg; if the patient requires aggressive treatment to lower blood pressure to a specified limit; if the patient is taking anticoagulants or has a bleeding tendency; and / or if the patient has recently undergone invasive surgical procedures. Therefore, only a small fraction of selected stroke patients are eligible to receive t-PA.

[0008] Obstructive embolus have also been mechanically removed from various parts of the vascular system over the years. Mechanical treatment has involved capturing and removing thrombi, dissolving thrombi, destroying and aspirating thrombi, and / or creating a pathway through the thrombus. One of the first mechanical devices developed for stroke treatment is the MERCI Retriever System (Concentric Medical, Redwood City, California). It uses a balloon-guided catheter to access the internal carotid artery (ICA) from the femoral artery. A microcatheter is positioned through the guide catheter and used to deliver a coiled retriever across the thrombus, and then retracted to deploy the retriever around the thrombus. The microcatheter and retriever are then retracted into the balloon-guided catheter for the purpose of pulling in the thrombus while the balloon is inflated, and a syringe is connected to the balloon-guided catheter to aspirate the guide catheter during thrombus retrieval. This device initially showed better results compared to thrombolytic therapy alone.

[0009] Other thrombectomy devices utilize expandable cages, baskets, or snares to capture and retrieve thrombi. Temporary stents, sometimes called stent retrievers or revascularization devices, are used to remove or retrieve thrombi and restore blood flow to the vessels. A range of devices that use active laser or ultrasonic energy to break up thrombi are also available. Other active energy devices have been used in conjunction with intra-arterial thrombolytic injection to accelerate thrombus dissolution. Many of these devices are used in conjunction with aspiration to aid in thrombus removal and reduce the risk of embolism. Thrombus aspiration has also been used with single-lumen catheters and syringes or suction pumps, with or without aiding thrombus disruption. Devices that apply power-fluid vortices in combination with aspiration have been used to improve the effectiveness of this thrombectomy method. Finally, if thrombus removal or dissolution is not possible, balloons or stents have been used to create a patent lumen within the thrombus. [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] Despite the foregoing, there is still a need for new devices and methods to treat vascular occlusions in the body, including acute ischemic stroke and obstructive cerebrovascular disease. In particular, as will be discussed in more detail below, anatomically adapted catheter designs are needed due to the variability in the level of tortuosity of the intracranial carotid arteries (e.g., the pyramidal-cavernosal pathway) and the large variability of specific segments in stroke patients. [Means for solving the problem]

[0011] According to one embodiment, a neurovascular catheter for insertion into a patient's internal carotid artery is provided. In some embodiments, the neurovascular catheter may include an elongated flexible body and a flexible distal portion. The elongated flexible body may include a length of less than about 110 cm and may include a flexible distal portion. The flexible distal portion may include a length between about 10 cm and about 18 cm. The flexible distal portion may include a distal tip, a transition portion, and a support portion. In some embodiments, the distal tip is configured to be positioned within the cavernous segment of the internal carotid artery. In some embodiments, the proximal transition portion of the distal tip has less flexibility than the distal tip and is configured to be positioned within the pyramidal segment of the internal carotid artery. In some embodiments, the proximal support portion of the transition portion has less flexibility than the transition portion. In some embodiments, the support portion is configured to extend proximal to the base of the patient's skull.

[0012] In any of the embodiments described herein, the stiffness of the catheter portion is determined using a cantilever test, such as a cantilever test with a gauge length of 5 mm and a displacement of 4 mm, to determine the peak load value.

[0013] In some embodiments, the elongated flexible body has a length between approximately 98 cm and 102 cm. In some embodiments, the flexible distal portion has a length between approximately 12 cm and 16 cm. In some embodiments, the distal tip has a length between approximately 15 mm and 20 mm. In some embodiments, the transition portion has a length between approximately 1.0 cm and 3.5 cm. In some embodiments, the proximal end of the transition portion is positioned at a distance between approximately 5.5 cm and 7.5 cm from the distal end of the flexible distal portion. In some embodiments, the distal tip has a constant stiffness along its length. In some embodiments, the stiffness is between approximately 20 gF and 30 gF, and the stiffness is determined using a cantilever beam test with a gauge length of 5 mm and a displacement of 4 mm to determine the peak load value. In some embodiments, the flexible distal portion further includes a flexible portion that extends proximal to the distal tip and has a stiffness that increases along the length of the flexible portion. In some embodiments, the flexible portion has a first stiffness of about 20 gF to about 30 gF at the first end of the flexible portion, and a second stiffness of about 60 gF to about 65 gF at the second end of the flexible portion. In some embodiments, the transition portion has a constant stiffness along the length of the distal tip. In some embodiments, the stiffness is between about 50 gF and about 70 gF. In some embodiments, the support portion has a stiffness that increases along the length of the support portion. In some embodiments, the support portion has a first stiffness of about 60 gF to about 70 gF at the first end of the support portion, and a second stiffness of at least 400 gF at the second end of the support portion.

[0014] In another embodiment, a neurovascular catheter for insertion into a patient's internal carotid artery is disclosed. The neurovascular catheter may include an elongated body with a flexible distal segment. In some embodiments, the flexible distal segment includes a length between about 10 cm and about 18 cm. In some embodiments, the elongated flexible body includes a length of less than about 110 cm. The flexible distal segment may include a distal portion, a transition portion, and a support portion. The distal portion may include a tracking tip and a stiffening portion. In some embodiments, the distal portion has a length between about 20 mm and about 40 mm. The tracking tip may be configured to be positioned within the cavernous segment of the internal carotid artery. In some embodiments, the tracking tip has a length between about 10 mm and about 20 mm. The stiffening portion may be proximal to the tracking tip. In some embodiments, the stiffening portion has a length between about 5 mm and about 15 mm. The transition portion may be located proximal to the distal portion, which has lower flexibility than the tracking tip, and the transition portion is configured to be positioned within the pyramidal segment of the internal carotid artery, and the transition portion has a length between approximately 30 mm and approximately 40 mm. In some embodiments, the support portion is located proximal to the transition portion and has lower flexibility than the transition portion. In some embodiments, the support portion is configured to extend proximal to the base of the patient's skull, and the support portion has stiffness that increases proximal along the length of the support portion, and the support portion has a length between approximately 70 mm and approximately 80 mm. The flexible distal segment may have a flexibility profile measurable by a cantilever beam test using a gauge length of 5 mm and a displacement of 4 mm to determine the peak load value. In some embodiments, the peak load value at the tracking tip is less than approximately 30 gF. In some embodiments, the peak load value of the stiffness-increasing portion increases over the length of the stiffness-increasing portion from between approximately 20 gF and approximately 30 gF to between approximately 50 gF and approximately 70 gF. In some embodiments, the peak load value in the transition portion is between approximately 50 gF and approximately 70 gF. In some embodiments, the peak load value at the first end of the support portion is between approximately 50 gF and approximately 70 gF, and the peak load value at the second end of the support portion is at least approximately 400 gF.

[0015] In some embodiments, the elongated flexible body has a length of approximately 100 cm. In some embodiments, the flexible distal segment has a length of approximately 14 cm. In some embodiments, the distal portion has a length of approximately 30 mm. In some embodiments, the tracking tip has a length of approximately 17 mm. In some embodiments, the stiffening portion has a length of approximately 13 mm. In some embodiments, the transition portion has a length of approximately 35 mm. In some embodiments, the support portion has a length of approximately 75 mm.

[0016] In another embodiment, a neurovascular catheter for insertion into a patient's internal carotid artery is disclosed. In some embodiments, the neurovascular catheter includes a flexible distal segment for insertion into the patient's internal carotid artery. The flexible distal segment may include a distal portion, a transition portion, and a support portion. In some embodiments, the distal portion includes a tracking tip and a stiffening portion. The tracking tip may be configured to be positioned within the cavernous segment of the internal carotid artery. In some embodiments, the transition portion may be configured to be positioned within the pyramidal segment of the internal carotid artery. The support portion may be configured to extend proximal to the base of the patient's skull. In some embodiments, the flexible distal segment may have a flexibility profile measurable by a cantilever test using a gauge length of 5 mm and a displacement of 4 mm to determine the peak load value. In some embodiments, the peak load value at the tracking tip is less than approximately 30 gF. In some embodiments, the peak load value in the stiffness-increasing portion increases over the length of the stiffness-increasing portion from between approximately 20gF and 30gF to between approximately 50gF and 70gF. In some embodiments, the peak load value in the transitional portion is between approximately 50gF and 70gF. In some embodiments, the peak load value at the first end of the support portion is between approximately 50gF and 70gF, and the peak load value at the second end of the support portion is at least approximately 400gF.

[0017] In some embodiments, the flexible distal segment has a length between approximately 10 cm and approximately 18 cm. In some embodiments, the distal portion has a length between approximately 20 mm and approximately 40 mm. In some embodiments, the tracking tip has a length between approximately 10 mm and approximately 20 mm. In some embodiments, the stiffening portion has a length between approximately 5 mm and approximately 15 mm. In some embodiments, the transition portion has a length between approximately 30 mm and approximately 40 mm. In some embodiments, the support portion has a length between approximately 70 mm and approximately 80 mm.

[0018] In another embodiment, a method for accessing the petrosal-cavernosal segment of a patient is disclosed. The method may include providing a catheter comprising a flexible distal segment including a distal portion having a tracking tip and a stiffening portion, a transition portion, and a support portion. In some embodiments, the method includes the step of advancing the flexible distal segment of the catheter in such a way into the patient's internal carotid artery. The tracking tip of the flexible distal segment may be positioned within the cavernous segment of the internal carotid artery. The transition portion may be positioned within the petrosal segment of the internal carotid artery. The support portion may extend to the base of the patient's skull.

[0019] In some embodiments, the tracking tip of the flexible distal segment of the catheter is inserted until tactile feedback is received at the proximal end of the catheter indicating that the transition portion has engaged with the anatomical structure of the pyramidal segment. In some embodiments, the catheter has a length of less than 110 cm. In some embodiments, the catheter has a length of 100 cm. In some embodiments, the flexible distal segment has a length between 10 cm and 18 cm. In some embodiments, the flexible distal segment has a length of 14 cm. In some embodiments, the distal portion has a length between approximately 20 mm and 40 mm. In some embodiments, the distal portion has a length of approximately 30 mm. In some embodiments, the tracking tip has a length between approximately 10 mm and 20 mm. In some embodiments, the tracking tip has a length of approximately 17 mm. In some embodiments, the stiffening portion has a length between approximately 5 mm and 15 mm. In some embodiments, the stiffening portion has a length of approximately 13 mm. In some embodiments, the transition portion has a length between approximately 30 mm and 40 mm. In some embodiments, the transition portion has a length of approximately 35 mm. In some embodiments, the support portion has a length between approximately 70 mm and approximately 80 mm. In some embodiments, the support portion has a length of approximately 75 mm. In some embodiments, the distal tip is more flexible than the transition portion, and the transition portion is more flexible than the support portion. In some embodiments, the method is configured to treat tandem lesions.

[0020] In some embodiments, the flexible distal segment of the method may include a flexible profile measurable in a cantilever beam test using a gauge length of 5 mm and a displacement of 4 mm to determine the peak load value. In some embodiments, the peak load value at the trailing tip is less than about 30 gF. In some embodiments, the peak load value in the stiffening portion increases over the length of the stiffening portion from between about 20 gF and about 30 gF to between about 50 gF and about 70 gF. In some embodiments, the peak load value in the transition portion is between about 50 gF and about 70 gF. In some embodiments, the peak load value at the first end of the support portion is between about 50 gF and about 70 gF, and the peak load value at the second end of the support portion is at least about 400 gF.

[0021] Any feature, structure, or step disclosed herein may be replaced, combined with, or omitted from any other feature, structure, or step disclosed herein. Furthermore, for the purpose of summarizing this disclosure, specific aspects, advantages, and features of embodiments are described herein. It should be understood that not all or any of such advantages will necessarily be achieved by any particular embodiment disclosed herein. Individual aspects of this disclosure are not essential or indispensable. Further features and advantages of embodiments will become apparent to those skilled in the art in the following detailed description, in conjunction with the accompanying drawings and claims. [Brief explanation of the drawing]

[0022] [Figure 1A] This figure shows an alternative series of steps involved in accessing a neurovascular occlusion for aspiration. [Figure 1B] Another diagram shows an alternative sequence of steps involved in accessing a neurovascular occlusion for aspiration. [Figure 1C] Another diagram shows an alternative sequence of steps involved in accessing a neurovascular occlusion for aspiration. [Figure 1D]Another figure showing an alternative series of steps involved in accessing a neurovascular occlusion for aspiration. [Figure 1E] Another figure showing an alternative series of steps involved in accessing a neurovascular occlusion for aspiration. [Figure 1F] Another figure showing an alternative series of steps involved in accessing a neurovascular occlusion for aspiration. [Figure 2] A schematic diagram of the internal carotid artery. [Figure 3A] An anatomical photograph of the carotid siphon and variations in the degree of tortuosity that may be present. [Figure 3B] An anatomical photograph of the posterior vertebral artery and variations in the degree of tortuosity that may be present. [Figure 3C] An anatomical photograph of the cavernous segment of the internal carotid artery and variations in the degree of tortuosity that may be present. [Figure 3D] An anatomical photograph of the cervical segment of the internal carotid artery and variations in the degree of tortuosity that may be present. [Figure 4A] A figure showing a catheter intended for a higher placement within the brain when having a distal placement within the M1 segment of the middle cerebral artery. [Figure 4B] A figure showing a catheter intended for a higher placement within the brain when having a low placement within the pyramidal segment of the internal carotid artery. [Figure 4C] A figure showing a catheter intended for a lower placement within the brain when having a low placement within the pyramidal segment of the internal carotid artery. [Figure 5A] A figure showing an embodiment of the distal end of the catheter of the present disclosure. [Figure 5B] A figure showing an embodiment of the tracking tip of the distal end of the disclosed catheter of Figure 5A. [Figure 6A] A schematic diagram explaining a flexible profile that may be desirable for the distal segment of the catheter. [Figure 6B] Another schematic diagram explaining a flexible profile that may be desirable for the distal segment of the catheter. [Figure 7] This is a graph of the catheter's elastic modulus or durometer along its length, from the proximal end to the distal end. [Figure 8] This diagram shows a tandem lesion located in the external carotid artery. [Figure 9A] This figure shows a catheter with a longer distal flexible segment compared to Figure 9B. [Figure 9B] This figure shows a catheter with a shorter distal flexible segment compared to Figure 9A. [Modes for carrying out the invention]

[0023] overview Although primarily described in the context of neurovascular aspiration catheters having a single central lumen, the catheters of this disclosure can be readily modified to incorporate additional structures, such as permanent or removable column strength-enhancing mandrels, two or more lumens for allowing the injection of drugs, contrast agents or irrigation agents, or for supplying inflation medium to an inflatable balloon carried by the catheter, or a combination thereof, as will be readily apparent to those skilled in the art in view of the disclosure herein. Furthermore, while embodiments of the catheters of this disclosure are primarily described in the context of removing occlusive material from distant vascular systems in the brain, they are applicable as access catheters for the delivery and removal of any of a variety of diagnostic or therapeutic devices, with or without aspiration.

[0024] The catheters disclosed herein can be readily adapted for use throughout the body. For example, embodiments of the catheter shafts of this disclosure may be sized to accommodate use throughout the coronary and peripheral vascular systems, the gastrointestinal tract, the urethra, the ureters, the Fallopian tube, and other lumens and potential lumens. The catheters disclosed herein may also be used to provide minimally invasive percutaneous tissue access for purposes such as diagnostic or therapeutic access to solid tissue targets (e.g., biopsy or tissue resection of the breast, liver, or brain), delivery of laparoscopic instruments, or access to bone such as the spine for delivery of screws, bone cement, or other instruments or implants. Examples of such catheters are shown, for example, in U.S. Patent No. 10,183,145 and U.S. Patent No. 10,835,272 by Yang et al., the disclosures of which are incorporated herein by reference in their entirety.

[0025] Overview of treatment methods Treatment of occlusion in the internal carotid artery Figures 1A to 1F illustrate a method for aspirating a thrombotic occlusion. A transition guidewire and a transition guide sheath can be used for the aspirating thrombotic occlusion. The transition guidewire has a flexible, traceable distal segment with a smaller diameter, allowing the transition guidewire to advance deeper into the neurovascular system. In some embodiments, the use of a transition guidewire and a transition guide sheath that can be advanced to an area near the thrombus eliminates the need to use a second guidewire or reperfusion catheter to reach the thrombus.

[0026] Referring to Figure 1A, the introduction sheath 200 is introduced into the femoral artery 300. The outer diameter of the introduction sheath 200 may be approximately 12F, 11F, 10F, 9F, 8F, 7F, or less than 6F. Next, a transition guide sheath 222, such as an access and aspiration combination catheter, which will be discussed in more detail below, is inserted into the femoral artery 300 through the introduction sheath 200. The outer diameter of the guide sheath 222 may be approximately 9F, 8F, 7F, 6F, 5F, 4F, or less than 3F. Referring to Figure 1B, the insertion catheter 224 is inserted through the transition guide sheath 222. The outer diameter of the insertion catheter 224 may be approximately 9F, 8F, 7F, 6F, 5F, 4F, or less than 3F, and the inner diameter of the transition guide sheath 222 may be larger than the outer diameter of the insertion catheter 224. In some cases, the first guidewire may be introduced through the insertion catheter 224 (not shown in Figure 1B). The diameter of the proximal section of the first guidewire may be approximately 0.079”, 0.066”, 0.053”, 0.038”, 0.035”, 0.030”, or less than 0.013”.

[0027] The transition guide sheath 222, insertion catheter 224, and optionally a first guidewire are traced to the aortic arch 310. See Figure 1B. The insertion catheter 224 may be used to select the origin of the vessel. In Figure 1B, the insertion catheter 224 engages with the origin 1216 of the brachiocephalic artery 360. Angiography may be performed by injecting contrast agent through the insertion catheter 224. If the first guidewire is used before angiography is performed, it is preferable that the first guidewire be removed before injecting the contrast agent.

[0028] Referring to Figure 1C, the transition guidewire 230 is inserted through the lumen of the insertion catheter 224 or guide sheath 222. At least a portion of the diameter of the transition guidewire 230 (e.g., the proximal diameter) is substantially the same as the diameter of the first guidewire 232. At least a portion of the diameter of the transition guidewire 230 (e.g., the distal diameter) may be smaller than the diameter of the first guidewire 232 and may have a diameter along the proximal segment of at least about 0.030” and about 0.038” in one implementation. The transition begins in the range of about 15 cm to about 30 cm from the distal end, typically within the range of about 20 cm or 25 cm or less from the distal end, and from there distally tapers to a diameter of about 0.018” or less and about 0.016” or less in one implementation.

[0029] Referring to Figure 1D, the insertion catheter 224 may be removed if it is too rigid to advance to the MCA 330 when used. In some embodiments, the transition guidewire 230 provides sufficient backup support so that the access and aspiration combination catheter 224 can advance directly on the transition guidewire without an intervening device. The transition guidewire 230 is then advanced to the MCA 330. The transition guidewire 230 may have a distal segment having a smaller diameter than the guidewire 1126 described in a similar system. The distal segment of the transition guidewire 230 has a flexible, non-traumatic tip and can be traced to the distant neurovascular system, such as the MCA 330, distal to the pyramidal segment 370 of the ICA 320.

[0030] Referring to Figure 1E, the transition guide sheath 222 is advanced to or beyond the spongy segment 350 or brain segment 340 of the ICA 320. In some embodiments, the transition guide sheath 222 has a flexible but traceable distal segment, which is described in more detail below, for example, in relation to Figure 2, so that the transition guide sheath 222 may advance beyond the pyramidal segment 370 to the spongy segment 350 or brain segment 340 of the ICA 320. A larger proximal diameter and / or a more rigid body of the transition guidewire 230 can provide better support for the transition guide sheath 222 to trace through the vascular system.

[0031] Referring to Figure 1F, after the transition guide sheath 222 has advanced to brain segment 340 of ICA 320, the transition guidewire 230 is removed. Vacuum pressure is then applied to the proximal end of the transition guide sheath 222 to aspirate the thrombus 400 through the central lumen of the transition guide sheath 222. The inner diameter of the transition guide sheath 222 may be approximately equal to or greater than approximately 0.100”, 0.088”, 0.080”, 0.070”, or 0.060”. The inner diameter of the transition guide sheath 222 is larger than that of the aspiration catheter 1128, which leads to more effective aspiration. The cross-sectional area of ​​the central lumen of the transition guide sheath 222 may be approximately twice the cross-sectional area of ​​the largest currently available aspiration catheter 1128.

[0032] If the guide sheath 222 cannot track deep enough within the distal vascular system to reach a thrombus or other desired target site, an extendable segment, as discussed elsewhere in this specification, can be introduced at the proximal end of the sheath 222 and advance distally, extending beyond the distal end of the sheath 222, thereby extending the reach of the aspiration system. In some embodiments, the extension segment has an ID of about 0.070”. Alternatively, the ID of the insertion catheter may be larger than the OD of the guidewire by a sufficient amount to provide a contrast agent injection lumen between the guidewire and the insertion catheter, allowing for the introduction of contrast agent without the need to remove the guidewire.

[0033] If the thrombotic material cannot be drawn into the sheath 222 or extension segment under constant vacuum, a pulsatile vacuum may be applied. If the pulsatile vacuum does not adequately capture the thrombus, a stirrer may be advanced through the sheath 222 and extension segment to facilitate the drawing of the thrombus into the central lumen. Alternatively, the transition may have reduced flexibility but maintain a constant outer diameter throughout.

[0034] Overview of intracranial catheters In some embodiments, pre-formed insertion catheters can be used to reach intracranial anatomical structures. These insertion catheters can be configured to help guide the catheter to reach a target site within the intracranial anatomical structure during initial ascent. Subsequently, an aspiration catheter can be used to reach the occlusion (e.g., the thrombus surface) and remove it from the body. Generally, about 86% of thrombi are located in the M1 segment of the middle cerebral artery (MCA). However, depending on the location of the thrombus, the aspiration catheter may often have insufficient support to reach the site of the thrombus. In some embodiments, the occlusion may be located within the internal carotid artery.

[0035] Figure 2 shows a schematic and anatomical diagram of the internal carotid artery. The internal carotid artery can exhibit considerable variability in length and tortuosity. In particular, narrow radial bends are present in the treatment pathways most commonly found in the carotid siphon, vertebral (posterior), petrous / cavernosal, cervical, and brachiocephalic (arch) regions.

[0036] Figures 3A to 3D show examples of the range and variability of tortuosity that can be present in various parts of the internal carotid artery. Figure 3A shows the range of severity of tortuosity that can be present in the carotid siphon. Figure 3B shows the range of severity of tortuosity that can be present in the posterior vertebral artery. Figure 3C shows the range of severity of tortuosity that can be present in the cavernous segment. Figure 3D shows the range of severity of tortuosity that can be present in the cervical segment. Because there is a trade-off between the ease of handling / flexibility of softer materials and the force transmission provided by stiffer materials, different catheter materials and / or flexibility profiles are required depending on the severity of tortuosity and the length to be reached.

[0037] Another consideration in the development of intracranial catheters is the length of specific segments of the internal carotid artery. For example, stroke patients exhibit significant variation in the petrosal-cavernosal segment of the internal carotid artery. Therefore, stroke patients, in particular, may have petrosal-cavernosal segments with variations of approximately 6.2 cm. This variation is significantly larger than that seen in the general population. Due to the large variation in the length of the pathway from the petrosal to the cavernous segment, a single catheter design may not be able to meet the needs of all patients.

[0038] Therefore, anatomically fitted catheter designs may be desirable to accommodate varying levels of tortuosity and large variability in the length of the patient's pyramidal-cavernosal pathway. Furthermore, catheters may be designed to have an appropriate length and flexibility profile not only to navigate arterial tortuosity but also to provide the physician with sufficient support and force along the length of the distal end of the catheter to advance the distal tip of the catheter to the target position. In some embodiments, the catheters of this disclosure are designed for stroke patients with pyramidal-cavernosal segments of average or less-than-average length.

[0039] Enhanced control and improved treatment efficiency In some embodiments, the disclosed catheter embodiments may have a shorter effective length than existing catheters to provide a more neutral arm position during operation. In some embodiments, a shorter effective length of the catheter from the distal hub can improve the ergonomics of manual placement and the efficiency of the procedure. A shorter catheter length reduces the range of the physician's reach and can improve the ergonomics of movement from the introduction sheath to the hub during the procedure. In some embodiments, the effective length of the catheter is any value within the enumerated range including about 100 cm, between about 98 cm and about 102 cm, between about 96 cm and about 104 cm, between about 94 cm and about 106 cm, between about 92 cm and about 108 cm, between about 90 cm and about 110 cm, between about 88 cm and about 112 cm, between about 86 cm and about 114 cm, between 84 cm and about 116 cm, between about 82 cm and about 118 cm, between about 80 cm and about 120 cm. The length of the catheter provided is compatible with commercially available auxiliary devices (e.g., insertion catheters, carotid artery stent delivery systems).

[0040] Anatomically driven design A tortuous vascular system is a common reason why vascular occlusions in the body cannot be treated, as it is impossible to track the catheter to the site of disease. Guiding a catheter through tortuous anatomical structures such as the neurovascular system can be challenging. The catheter must be extremely flexible so as not to damage the vessel wall. At the same time, it must be able to pass through multiple tight bends without kinking. Furthermore, it must have sufficient column strength to transmit axial force to advance through the vascular system. All of these performance characteristics are competing design requirements. Optimizing one performance characteristic without sacrificing others is difficult. In some embodiments, the flexible distal end of the catheter of this disclosure may comprise a multilayer structure having a high degree of flexibility and sufficient pushing capacity to reach deep into the cerebral vascular system, such as to a depth at least comparable to that of the distal corpus cavernosum.

[0041] Embodiments of the catheters of this disclosure are designed to accommodate specific anatomical needs. In particular, the aspiration catheters are designed to consistently navigate to the distal cavernous segment. In some embodiments, the catheter can reach the M1 segment of the MCA in patients with less tortuosity. As discussed above, the catheters in some embodiments are designed for use in patients with average or below-average pyramidal-cavernosal segments. In some examples, the disclosed catheters are designed to align with lower placements within the internal carotid artery (i.e., the pyramidal segment). In some embodiments, the disclosed catheters are configured for use in less tortuosic neurovascular systems. In some embodiments, the length of the distal flexible segment of the catheter is such that the length of the flexible distal segment roughly corresponds to the distance between the ECA bifurcation and the arch, thus enabling the catheter to treat tandem lesions.

[0042] Low-position catheter In some embodiments, the distal tip of the catheter can be positioned anywhere within the skull along the length of the internal carotid artery. Many existing catheters are configured to allow the distal tip to be positioned higher within the brain. For example, the distal tip can be positioned within the M1 of the middle cerebral artery distal to the internal carotid artery (ICA). Positioning the catheter above the ICA within the brain can have many advantages. For example, if the catheter is positioned further into the skull, the device can be made more functional within the brain. However, many physicians are uncomfortable advancing the catheter so far into the skull due to the potential for complications and arterial rupture during the procedure. Therefore, there is a need for a catheter that can be advanced to a lower position within the brain (i.e., the vertical portion of the pyramidal segment of the internal carotid artery) while still providing sufficient support for later advancement of the suction catheter.

[0043] In some embodiments, the catheters of the present disclosure have material properties designed to allow the catheter to be positioned in a lower location (e.g., a conical segment) while providing sufficient support for the aspiration catheter as it advances along its length.

[0044] Because catheters are designed to fit specific anatomical needs, catheters intended for placement deeper within the brain, intracranially (e.g., distal to the horizontal portion of the pyramidal segment), are often unsuitable for placement in lower portions of arteries (e.g., proximal portions of the pyramidal segment, e.g., vertical portions of the pyramidal segment). As an example, Figure 4A shows the use of a catheter 100 designed for a higher placement within the brain when placed within the M1 segment of the middle cerebral artery. The transition segment 110 between the proximal, more rigid segment 120 and the adjacent distal, more flexible segment 130 remains within the tortuous pyramidal segment vascular system at the base of the skull, stabilizing the catheter in place. As illustrated, the higher rigidity of the catheter proximal to the transition segment 110 in this higher placement catheter creates a “lock” 40 within the artery, providing support as the suction catheter advances through it.

[0045] In contrast, Figure 4B shows a catheter 100 designed for a higher placement, instead of a lower placement within the internal carotid artery. As illustrated, the transition segment 110 is positioned well below the base of the skull so that the distal end of the more rigid proximal segment 120 cannot engage with the tortuosity to form a soft lock. The flexible distal segment 130 extends proximal to the base of the skull and cannot form a soft lock 40 because it places the transition too far proximal to the base of the skull. This flexible distal segment 130 cannot absorb force transmission and adequately support the suction catheter as it advances distally.

[0046] Figure 4C shows a catheter designed to be positioned lower in the brain (i.e., in the petrous portion of the internal carotid artery). The distal ends 1122 of the transition segment 1110 and proximal segment 1120 engage within the blood vessel to help the catheter remain in place and provide support as the aspiration catheter advances through it. The transition segment 1110 between catheter segments having different material properties is preferably positioned away from the distal end of the catheter by an amount equal to the distance between the soft lock 1140 and the intended final location of the distal tip of the catheter. This allows the physician to receive tactile feedback of the soft lock in all cases by selecting a catheter designed to reach its particular target site, regardless of the final position of the distal catheter tip. Thus, this design of the catheter preferably complements the anatomical structure in which the catheter is used.

[0047] Overview of anatomically fitted catheters Figure 5A shows an example of an anatomically adapted catheter 1000 for lower placement within the brain. Catheter 1000 is designed to consistently navigate the distal cavernous segment. In some embodiments, catheter 1000 is designed for use in patients with average or below-average pyramidal-cavernosal segments and / or patients with a less tortuosic neurovascular system. As will be discussed in more detail below, the distal segment 1100 of catheter 1000 is designed in some embodiments to be placed within the pyramidal segment of the internal carotid artery.

[0048] The catheter 1000 may include a distal segment 1100 and a proximal segment 1500. The distal segment 1100 may include a distal portion 1200, a transition portion 1300, and a support portion 1400. The distal segment 1100 can increase in flexibility as it extends distally from the support portion 1400 to the end of the distal portion 1200. In some embodiments, the distal segment 1100 may have a length of any value within the enumerated ranges including about 14 cm, between about 13 cm and about 15 cm, between about 12 cm and about 16 cm, between about 11 cm and about 17 cm, between about 10 cm and about 18 cm, and the endpoint. In some examples, the catheter has a stepped flexibility profile through multiple transitions between axially adjacent sidewall segments having a durometer that decreases distally. As will be described in more detail below, the catheter 1000 can provide sufficient pushability and support so that the insertion catheter remains stable during catheter delivery and advancement.

[0049] In some embodiments, to reduce the range of reach of the physician and improve the ergonomics of movement from the introduction sheath to the hub during the procedure, the catheter 1000 may have a total length of approximately 100 cm, between approximately 98 cm and approximately 102 cm, between approximately 96 cm and approximately 104 cm, between approximately 94 cm and approximately 106 cm, between approximately 92 cm and approximately 108 cm, between approximately 90 cm and approximately 110 cm, and any value within the enumerated range including the endpoint.

[0050] Distal portion and flexible tip of the distal segment In some embodiments, the distal portion 1200 can form the most distal part of the distal segment 1100 of the catheter 1000. The distal portion 1200 includes sufficient flexibility to reach the intracranial vascular system above the base of the skull during access. The distal portion 1200 may include a tracking tip 1210 and a stiffening portion 1220 proximal to the tracking tip 1210.

[0051] In some embodiments, the distal portion 1200 may have a length of any value within the enumerated range, including about 0 cm to about 6 cm, about 1 cm to about 5 cm, about 2 cm to about 4 cm, or about 3 cm, and the endpoint. In some embodiments, the distal portion 1200 may contain a material such as urethane.

[0052] The tracking tip 1210 can form the distal portion 1200 and the most distal segment of the catheter 1000. The tracking tip 1210 can guide the catheter 1000 and guide the catheter into bends as it advances. In some embodiments, the tracking tip 1210 can form the softest part of the catheter, guiding the catheter and causing it to buckle and change direction when it hits an arterial wall. The tracking tip 1210 of the catheter can be softer than the distal segment 1100 and the rest of the catheter 1000 to improve the catheter's ability to navigate tortuous intracranial vessels and follow the tortuous path to reach a target location.

[0053] In some embodiments, the tracking tip 1210 includes a stretched or softened layer. This layer may first be formed by dipping-coating a mandrel (not shown) to provide a thin-walled tubular body inside the layer of the catheter body. The dipping coating may be produced by coating a wire, such as silver-clad copper wire, with a material such as PTFE, expanded PTFE (e-PTFE), thermoplastic polyurethane (e.g., inherently hydrophilic and lubricating inner diameter characteristics, low durometer), fluorinated ethylene propylene (FEP), or polyvinylidene fluoride (PVDF). The mandrel may then be stretched axially to reduce its diameter and subsequently removed, leaving a tubular inner liner. The outer surface of this tubular inner liner can then be coated with a soft binding layer, such as polyurethane, to produce a layer having a thickness of about 0.005 inches or less, and in some embodiments about 0.001 inches.

[0054] In some embodiments, the tracking tip 1210 includes a stretched or softened layer to increase the flexibility of at least that section of the catheter. In some examples, softening may be achieved by one or more of the following: stretching the inner liner; applying one or more holes (e.g., any embodiment of the holes described elsewhere herein) to the inner liner; applying heat to the inner liner; chemically treating the inner liner; or changing the manufacturing parameters of the inner liner.

[0055] In some embodiments, the stretch range of at least a portion of the inner liner may be approximately 20% to 150% stretch, approximately 20% to 75% stretch, approximately 100% to 150% stretch, approximately 50% to 90% stretch, approximately 60% to 80% stretch, approximately 70% to 80% stretch, approximately 50% to 100% stretch, 20% to 90% stretch, and so on. For example, the inner liner of a softened or stretched portion may have a thickness of approximately 0.0001 inches to approximately 0.001 inches, approximately 0.00005 inches to approximately 0.0005 inches, approximately 0.00025 inches to approximately 0.00075 inches, approximately 0.0004 inches to approximately 0.0006 inches, approximately 0.0003 inches to approximately 0.0007 inches, and approximately 0.0004 inches to approximately 0.0008 inches.

[0056] In some embodiments, the tracking tip 1210 may include an angled distal tip. Figure 5B shows one embodiment of the angled tracking tip 1210. To provide catheter tracking, the tracking tip 1210 may include a marker band. The marker band may have at least one, optionally two or more, axially extending slits along its entire length to allow radial expansion. The marker band may include any of a variety of radiopaque materials, such as a platinum / iridium alloy. In some embodiments, the tracking tip 1210 may have an axial length of any value within the enumerated ranges including about 17 mm, between about 16 mm and about 18 mm, between about 15 mm and about 19 mm, between about 15 mm and about 20 mm, between about 14 mm and about 20 mm, between about 13 mm and about 21 mm, between about 12 mm and about 22 mm, between about 11 mm and about 23 mm, between about 10 mm and about 24 mm, and the endpoint.

[0057] Transition area of ​​the distal segment The distal segment 1100 may include a transition portion 1300 positioned at the proximal end of the distal portion 1200. In some embodiments, the transition portion 1300 is positioned on the distal segment 1100 to be anatomically compatible in order to engage with the pyramidal segment of the internal carotid artery to form a soft lock. The soft lock may be configured to fix the flexible distal segment 1100 within the pyramidal segment to provide support as the suction catheter advances. In some embodiments, the transition portion 1300 may have a length of any value between approximately 0 cm and approximately 7 cm, approximately 1 cm and approximately 6 cm, approximately 1.0 cm and approximately 3.5 cm, approximately 2 cm and approximately 5 cm, approximately 3 cm and approximately 4 cm, or approximately 3.5 cm, including the endpoint.

[0058] Support portion of the distal segment The distal segment 1100 may include a support portion 1400 positioned at the proximal end of the transition portion 1300. In some embodiments, the support portion 1400 forms the proximal end of the distal segment 1100 and extends proximal from the base of the skull. The support portion 1400 can increase the stiffness in the proximal direction between the proximal end of the transition portion 1300 and the distal end of the proximal segment 1500. The support portion 1400 can form the stiffest portion of the distal segment 1100. In some embodiments, the flexible profile of the support portion 1400 provides sufficient pushability and support to the distal portion 1200 of the distal segment 1000 and the transition portion 1300 when the catheter 1000 advances into the cavernous segment of the internal carotid artery and the transition portion 1300 forms a soft lock in the pyramidal segment of the intracranial carotid artery. In some embodiments, the support portion 1400 can have a length of any value within the enumerated ranges, including about 7.5 cm, between about 7 cm and about 8 cm, between about 6.5 cm and about 8.5 cm, between about 6 cm and about 9 cm, between about 5.5 cm and about 10 cm, and the endpoint.

[0059] Proximal segment In some embodiments, the proximal segment 1500 forms the proximal end of the catheter 1000. As shown in Figure 5, the proximal segment 1500 may extend from the proximal end of the distal segment 1100. In some embodiments, the proximal segment 1500 includes a more rigid material such as nylon 12. In some embodiments, the proximal segment 1500 may have a length of any value between approximately 86 cm, between approximately 80 cm and approximately 90 cm, between approximately 75 cm and approximately 95 cm, between approximately 70 cm and approximately 100 cm, and the enumerated range including the endpoint.

[0060] Flexibility profile of the distal segment overview The distal shaft stiffness profile can be sufficiently flexible for easy intracranial access during the initial ascent. In some embodiments, the flexibility of the catheter profile includes a seamless transition for optimal navigation around and along tortuous intracranial vessels. In some examples, the catheter minimizes shaft kinking, buckling forces, and compressive forces by including a rate of change in stiffness along the distal shaft that corresponds to anatomical twists, in order to improve support during both access and catheter delivery. An anatomically fitted stiff transition profile can also provide stability when delivering smaller catheters. The transition profile also ensures that the catheter does not move proximal and remains seated in the desired position when translating smaller catheters. In some embodiments, the flexibility profile of the distal flexible segment provides excellent support when positioned proximal to the siphon in patients with average anatomical structures. In some embodiments, the flexibility profile of the catheter provides stability to the catheter when the physician wishes to keep the device low and during the initial ascent.

[0061] The catheter 1000 is configured to advance through the internal carotid artery such that its tracking tip 1210 is positioned within the cavernous segment of the internal carotid artery. The flexibility profile of the distal segment 1100 is designed so that when the transition portion 1300 is seated in the pyramidal segment of the internal carotid artery (referred to herein as “soft lock”), the change in flexibility of the proximal and distal ends of the transition portion 1300 provides tactile feedback to the physician. The “soft lock” is provided in the form of mechanical tactile feedback to the physician, in which case there is a slight pushback in the catheter to indicate that the transition portion 1300 of the flexible distal segment 1200 has engaged with the anatomical structure of the pyramidal segment. In some examples, the support portion 1400 of the distal segment 1100 extends proximal to the base of the skull.

[0062] Figure 6A shows the flexibility profile of the distal segment 1100 of catheter 1000 as it extends from the distal tracking tip 1210 (on the left) to the support portion 1400 (on the right). In some embodiments, the flexibility of the catheter can be determined using a cantilever test. The cantilever test can be performed along the length of the catheter to characterize the local segment stiffness and rate of stiffness change. The transition and flexibility of interposed catheter shaft segments can be related to the anatomical flexures on which that region of the catheter is designed to navigate. In this application, the flexibility of catheter 1000 was tested in 6 mm increments over the length of the distal portion 1200, from the distal end of the tracking tip 1210 to the proximal end of the support portion 1400. The catheter 1000 is fixed at a distance of 5 mm from the target position to be measured. This is the gauge length (e.g., 5 mm) used in the cantilever test. Next, a force is applied to cause a 4 mm displacement at the target position of the catheter 1000, and the peak load is measured within the 4 mm displacement. The amount of force applied is measured at each sampling position (e.g., every 6 mm) to create a flexibility profile of the catheter 1000. The flexibility profile 2000 shown in Figure 18 shows the peak load (gF) experienced in 6 mm increments along the length of the distal segment 1100. The flexibility profile 2000 includes a section 2100 showing the peak load received by the tracking tip 1210 of the distal portion 1200, a section 2200 showing the peak load received by the stiffness-increasing portion 1220 of the distal portion 1200, a section 2300 showing the peak load received by the transition portion 1300, and a section 2400 showing the peak load received by the support portion 1400.

[0063] Section 2100 shows the flexibility profile along the length of the tracking tip 1210. As discussed above, Section 2100 represents the peak load along the length of the tracking tip 1210, measured by determining the amount of force required to displace the target position by 4 mm, with the peak load measured within a 4 mm displacement. In some embodiments, the tracking tip 1210 can have peak load values ​​of any value between approximately 20 gF and approximately 30 gF, between approximately 22 gF and approximately 28 gF, between approximately 24 gF and approximately 26 gF, and within the enumerated ranges including the endpoint. In some embodiments, the tracking tip 1210 can have peak load values ​​of any value between 18 gF, between approximately 16 gF and approximately 20 gF, between approximately 14 gF and approximately 22 gF, between approximately 12 gF and approximately 24 gF, between approximately 10 gF and approximately 26 gF, and within the enumerated ranges including the endpoint.

[0064] Section 2200 shows the flexibility profile along the length of the stiffness-enhancing portion 1220. Section 2200 represents the peak load along the length of the stiffness-enhancing portion 1220, measured by determining the amount of force required to displace a target position by 4 mm, with the peak load measured within a 4 mm displacement. In some embodiments, the stiffness-enhancing portion 1220 can vary the peak load from a first peak load to a second peak load. The first peak load can be in any range of values ​​between approximately 20 gF and approximately 30 gF, between approximately 22 gF and approximately 28 gF, between approximately 24 gF and approximately 26 gF, and within the enumerated ranges including the endpoints. The second peak load can be any value within the listed ranges, including approximately 50gF to 70gF, approximately 52gF to 68gF, approximately 54gF to 66gF, approximately 56gF to 64gF, approximately 60gF to 65gF, and the endpoints.

[0065] Section 2300 shows the flexibility profile along the length of the transition section 1300. Section 2300 represents the peak load along the length of the transition section 1300, measured by determining the amount of force required to displace the target position by 4 mm, with the peak load measured within the 4 mm displacement. In some embodiments, the transition section 1300 may have peak load values ​​of any value within the enumerated ranges, including about 50 gF to about 70 gF, about 52 gF to about 68 gF, about 54 gF to about 66 gF, about 56 gF to about 64 gF, about 60 gF to about 70 gF, and the endpoint.

[0066] Section 2400 shows the flexibility profile along the length of the support portion 1400. Section 2400 represents the peak load along the length of the support portion 1400, measured by determining the amount of force required to displace the target position by 4 mm, and the peak load is measured within the 4 mm displacement. In some embodiments, the support portion 1400 can vary the peak load from a first peak load to a second peak load. The first peak load can be any range of values ​​within the enumerated ranges, including about 50 gF to about 70 gF, about 52 gF to about 68 gF, about 54 gF to about 66 gF, about 56 gF to about 64 gF, about 58 gF to about 62 gF, about 60 gF to about 70 gF, and the endpoints. The second stiffness is any value within the listed ranges, including at least about 400gF, between about 500gF and about 550gF, between about 510gF and about 540gF, between about 520gF and about 530gF, and the endpoints.

[0067] Figure 6B shows a schematic diagram of the catheter flexibility profile between the distal tracking tip 1210 and the transition portion 1300 of the distal segment 1100. In particular, Figure 6B highlights the importance of the rate of change in catheter flexibility. Since catheters are designed to conform to the patient's anatomical structure, changes in flexibility that are too rapid or too slow can impair the catheter's effectiveness as it traverses the patient's intracranial vascular system.

[0068] As discussed above with respect to Figure 6B, section 2100 represents the flexibility profile of the tracking tip 1200. As shown in the figure, section 2100 may have no change in flexibility or substantially no change (e.g., a slope of 0) because it is designed to be flexible enough for the distal portion 1200 (particularly the tracking tip 1210) to buckle and change direction when it hits a wall. Section 2300 represents the flexibility profile of the transition portion 1300. In some embodiments, the transition portion 2300 has no change in flexibility because it forms a "soft lock" within the pyramidal segment of the internal carotid artery.

[0069] Section 2200 represents the flexibility profile of the stiffness-increasing portion 1220 as the catheter material transitions between the tracking tip 1210 and the transition portion 1300. The slope of section 2200 can ensure that the catheter functions properly. In some embodiments, a slope of section 2200 that is too high or too low may result in a poorly performing catheter. Section 2200b shows the slope of section 2200, where the transition portion 1300 provides the catheter 1000 with sufficient support to navigate to the target anatomical structure and ensure a 1:1 transmission of hand movement relative to the advancement of the catheter tip. As shown in Figure 6A, segment 2200 shows that the stiffness of the stiffness-increasing portion 1220 can gradually increase from a first stiffness to a second stiffness over the length of the stiffness-increasing portion 1220. In some embodiments, the stiffness of the stiffness-increasing portion 1220 can gradually increase from less than about 30 gF to about 50 gF to about 70 gF over a length of at least about 12 mm. In some embodiments, the stiffness-increasing portion 1220 may have a first starting stiffness of any value between approximately 0gF and approximately 50gF, between approximately 10gF and approximately 40gF, between approximately 15gF and approximately 35gF, between approximately 17gF and approximately 33gF, and within the enumerated ranges including the endpoint. In some embodiments, the stiffness-increasing portion 1220 may have a second ending stiffness of any value between approximately 60gF, between approximately 55gF and approximately 65gF, between approximately 50gF and approximately 70gF, between approximately 45gF and approximately 75gF, between approximately 40gF and approximately 80gF, and within the enumerated ranges including the endpoint.

[0070] In contrast, sections 2200a and 2200c reflect flexibility profiles that are too high or too low for the transition section 1300. Section 2200a shows a slope that is too high (e.g., too much change in flexibility and too much stiffness). A slope that is too high can increase the risk of the catheter kinking. Section 2200c shows a slope that is too low (e.g., too little change in flexibility). A slope that is too low can result in poor force transmission, potentially causing the catheter to deviate from the curve, deviate, or tortuose within the blood vessel. If the catheter support is insufficient, the mechanical feedback of the catheter may feel spongy to the physician and may not provide a 1:1 transmission of hand movement relative to the advancement of the catheter tip.

[0071] Material properties of the distal segment Figure 7 shows a graph of the durometer or modulus I along the length of the catheter of this disclosure from the proximal end (x=0) to the distal end (x=1). A catheter according to one embodiment may have a durometer or modulus I that decreases as it approaches its distal end. The proximal end of the catheter has a higher durometer or modulus than the distal end of the catheter. The high durometer or modulus near the proximal end provides excellent backup support for the catheter. The durometer or modulus of the catheter is substantially constant along its length near the proximal segment 1500 of the catheter. Thereafter, the durometer or modulus of the catheter decreases near the distal segment 1100. The durometer or modulus of the catheter may begin to decrease at about 50%, about 70%, about 75%, about 80%, or about 90% of the length of the catheter from its proximal end (i.e., the transition region). A catheter may have a durometer or modulus that decreases continuously near its distal end by using a material with a lower durometer or modulus near its distal end, or by having a thinner catheter wall. The decrease in durometer or modulus near the distal end provides excellent traceability of the catheter. In some embodiments, a catheter may have a substantially constant bending load along its longitudinal length near its proximal end and a bending load that decreases rapidly near its distal end.

[0072] In some embodiments, the distal portion 1200 of the distal segment may have a durometer of any value within the enumerated ranges, including about 40A to about 73A, about 42A to about 70A, about 44A to about 68A, about 48A to about 66A, about 50A to about 64A, or about 62A, and the endpoint.

[0073] In some examples, the transition portion 1300 may include a material such as urethane. In some embodiments, the transition portion 1300 may be two or more materials having different hardnesses. In some examples, the distal end of the transition portion 1300 may have a durometer of about 60D to about 84D, about 62D to about 82D, about 64D to about 80D, about 66D to about 78D, about 68D to about 76D, about 70D to about 74D, or about 72D, and a durometer of any value within the enumerated range including the endpoint. In some embodiments, the proximal end of the transition portion 1300 may have a durometer of any value within the enumerated ranges including about 60D to about 84D, about 62D to about 82D, about 64D to about 80D, about 66D to about 78D, about 68D to about 76D, about 70D to about 74D, or about 72D, and the endpoint. In some embodiments, the proximal end of the transition portion 1300 may have a wall thickness greater than the wall thickness of the distal end of the transition portion 1300.

[0074] In some embodiments, the support portion 1300 may include a polyether block amide. The hardness of the support portion 1300 can be increased along its length as it extends from a distal end (e.g., adjacent to a transition portion 1300) to a proximal end (e.g., adjacent to a proximal segment 1500). In some embodiments, the support portion 1300 may include a plurality of adjacent segments in which the hardness increases. Each adjacent segment of the support portion 1300 may have a length of any value within the enumerated ranges, including about 0 cm to about 1.6 cm, about 0.2 cm to about 1.4 cm, about 0.4 cm to about 1.2 cm, about 0.6 cm to about 1.0 cm, or about 0.8 cm, including the endpoint. In some examples, each adjacent segment of the support portion 1300 may have a length between approximately 0 cm and approximately 2 cm, between approximately 0.2 cm and approximately 1.8 cm, between approximately 0.4 cm and approximately 1.6 cm, between approximately 0.6 cm and approximately 1.4 cm, between approximately 0.8 cm and approximately 1.2 cm, or approximately 1.0 cm, and any value between the listed ranges between the endpoints.

[0075] In some embodiments, each segment of the support portion 1300 may have a durometer of any value within the enumerated ranges, including about 30D to about 40D, about 31D to about 39D, about 32D to about 38D, about 33D to about 37D, about 34D to about 36D, or about 35D, and the endpoint. In some embodiments, each segment of the support portion 1300 may have a durometer of any value within the enumerated ranges, including about 32D to about 42D, about 33D to about 41D, about 34D to about 40D, about 35D to about 39D, about 36D to about 38D, or about 37D, and the endpoint. In some embodiments, each segment of the support portion 1300 may have a durometer of any value between approximately 35D and approximately 45D, approximately 36D and approximately 44D, approximately 37D and approximately 43D, approximately 36D and approximately 42D, approximately 35D and approximately 41D, or approximately 40D, and an enumerated range including the endpoint. In some embodiments, each segment of the support portion 1300 may have a durometer of any value between approximately 42D and approximately 52D, approximately 43D and approximately 51D, approximately 44D and approximately 50D, approximately 45D and approximately 49D, approximately 46D and approximately 48D, or approximately 47D, and an enumerated range including the endpoint. In some embodiments, each segment of the support portion 1300 may have a durometer of any value within the enumerated ranges, including about 50D to about 60D, about 51D to about 59D, about 52D to about 58D, about 53D to about 57D, about 54D to about 56D, or about 55D, and the endpoint. In some embodiments, each segment of the support portion 1300 may have a durometer of any value within the enumerated ranges, including about 54D to about 64D, about 55D to about 63D, about 56D to about 62D, about 57D to about 61D, about 58D to about 60D, or about 59D, and the endpoint. In some embodiments, each segment of the support portion 1300 may have a durometer of any value within the enumerated ranges, including about 58D to about 68D, about 59D to about 67D, about 60D to about 66D, about 61D to about 65D, about 62D to about 64D, or about 63D, and the endpoint.In some embodiments, each segment of the support portion 1300 may have a durometer of any value within the enumerated ranges, including about 67D to about 77D, about 68D to about 76D, about 69D to about 75D, about 70D to about 74D, about 71D to about 73D, or about 72D, and the endpoint.

[0076] Treatment of tandem lesions Tandem lesions most commonly occur at the external carotid artery (ECA) bifurcation and can be treated with carotid artery stenting. Figure 8 shows the location of a tandem lesion in the external carotid artery. The ECA bifurcation into the arch has a segment length of approximately 14 cm on average.

[0077] The disclosed catheter may also be designed to complement the anatomical structure of the artery so as to be configured to treat tandem lesions. In some embodiments, the disclosed catheter has sufficient support to treat tandem occlusion by delivering a carotid stent when the tip of the catheter is positioned at the ECA bifurcation. Since the distance between the ECA bifurcation and the arch is approximately 14 cm in many patients, the distal segment 1100 of the disclosed catheter intended for those patients has an effective length of approximately 14 cm but no more than approximately 18 cm. This effective length of the distal segment 1100 allows the catheter to be locked into the arch during carotid stent delivery. This also reduces the risk of displacement within the arch during stent delivery.

[0078] Figures 9A and 9B illustrate the advantages of a catheter 100 having a longer overall length (e.g., at least 110 cm) and a longer distal segment 110 (e.g., at least 18 cm) compared to a disclosed catheter 1000 (e.g., with an overall length of about 100 cm) and a shorter distal segment 1100 (e.g., about 14 cm). In Figure 9A, the proximal end 151 of the support portion 140 of catheter 100 is positioned lower than the proximal end 1510 of the support portion 1400 of catheter 1000 shown in Figure 9B.

[0079] Figure 9A shows a longer catheter 100 positioned between the ECA bifurcation and the arch. As shown, the transition portion 130 of catheter 100 is not properly locked within the arch. As a result, catheter 100 provides insufficient support, creating a risk of the distal portion 1200 deviating below the ascending aorta, and a risk of losing or impairing access to the arch during stent delivery. Figure 9B shows catheter 1000 having a shorter effective length (e.g., about 100 cm) and a shorter distal flexible segment (e.g., about 14 cm). In Figure 9B, the transition segment 1300 of catheter 1000 is positioned so that the proximal end of the support portion 1400 is locked within the arch. This reduces the risk of deviating within the arch during stent delivery. This ensures that the catheter provides sufficient support when the carotid stent is delivered to a tandem lesion.

[0080] Other implementation forms In some implementations, access to the catheter can be achieved using conventional techniques by incising peripheral arteries such as the right femoral artery, left femoral artery, right radial artery, left radial artery, right brachial artery, left brachial artery, right axillary artery, left axillary artery, right subclavian artery, or left subclavian artery. In emergency situations, incisions can also be made in the right or left carotid artery.

[0081] By avoiding tight fitting between the guidewire and the inner diameter of the guidewire lumen, the sliding properties of the catheter on the guidewire are improved. In ultra-small diameter catheter designs, it may be desirable to coat the outer surface of the guidewire and / or the inner surface of the wall defining the lumen with a lubricating coating to minimize friction as the catheter 1000 moves axially relative to the guidewire. Various coatings may be used, such as paralen, Teflon®, silicone, polyimide-polytetrafluoroethylene composites, or other materials known in the art and suitable depending on the material of the guidewire or the inner tubular wall.

[0082] In some examples, the catheter may be composed of any of the various biocompatible polymer resins that have suitable properties when formed into the tubular catheter body segments. Exemplary materials include polyvinyl chloride, polyethers, polyamides, polyethylene, polyurethane, and copolymers thereof.

[0083] The proximal body segment exhibits sufficient column strength to allow axial alignment of the catheter through the guide catheter, with at least a portion of the proximal body segment extending beyond the guide catheter into the patient's vascular system.

[0084] The catheter body may further include other components such as radiopaque fillers, colorants, reinforcing materials, and reinforcing layers such as braided or helical reinforcing elements. In particular, the proximal body segment may be reinforced to enhance its column strength and torque transmission (torque transmission) while preferably limiting its wall thickness and outer diameter.

[0085] In one aspect, a method is provided for aspirating a vascular occlusion from a remote site, comprising the steps of: advancing a guidewire to a distal site at least as distal as the cavernous segment of the internal carotid artery; advancing a tubular body directly on the guidewire to a distal site at least as distal as the cavernous segment; removing the guidewire from the tubular body; and aspirating the thrombus into the tubular body by applying a vacuum to the tubular body. In one aspect of the present disclosure, the method for aspirating a vascular occlusion includes the step of advancing the tubular body to a distal site at least as distal as the cerebral segment of the internal carotid artery. In another aspect of the present disclosure, the method for aspirating a vascular occlusion includes the step of advancing a guidewire to a distal site at least as distal as the middle cerebral artery.

[0086] In yet another aspect of this disclosure, a method for aspirating a vascular occlusion further includes the step of providing a tubular body with sufficient backup support to resist deviation of the tubular body into the aorta. In one aspect, the backup support may be provided by advancing the tubular body on a guidewire having a distal end positioned at least as distal to the cavernous segment of the internal carotid artery and a diameter of at least about 0.030 inches at the point where the guidewire enters the brachiocephalic artery. In another aspect, the backup support may be provided by advancing the tubular body on a guidewire having a distal end positioned at least as distal to the cavernous segment of the internal carotid artery and a diameter of about 0.038 inches at the point where the guidewire enters the brachiocephalic artery. The guidewire may be navigable to at least the cerebral segment of the internal carotid artery by having a distal segment with a diameter of about 0.020 inches or less. The guidewire may be navigable to at least the cerebral segment of the internal carotid artery by having a distal segment with a diameter of about 0.016 inches. The distal segment may have a length of approximately 25 cm or less. The distal segment may have a length of approximately 20 cm or less.

[0087] In one aspect, a method is provided for aspirating a vascular occlusion from a remote site, comprising the steps of: advancing a guidewire transvascularly through a vascular access point to a site distal to at least the cavernous segment of the internal carotid artery; accessing a site distal to at least the cavernous segment by advancing an access-and-suction combination catheter directly along the guidewire; removing the guidewire; and aspirating the thrombus with the access-and-suction combination catheter. In one aspect of the present disclosure, the method for aspirating a vascular occlusion includes the step of advancing an access-and-suction combination catheter distal to at least the cerebral segment of the internal carotid artery. In another aspect of the present disclosure, the method for aspirating a vascular occlusion includes the step of advancing a guidewire distal to at least the middle cerebral artery.

[0088] Disclaimer While the present invention has been described in relation to certain preferred embodiments, the invention may be incorporated into other embodiments by those skilled in the art in consideration of the disclosure herein. Accordingly, the scope of the invention is not intended to be limited by the specific embodiments disclosed herein, but rather to be defined by the entire scope of the appended claims.

[0089] Therefore, it should be understood that the embodiments of the present invention described herein are merely illustrative of the application of the principles of the present invention. References to the details of the exemplified embodiments herein are not intended to limit the claims, which themselves enumerate features considered essential to the present invention. The drawings are for illustrative purposes only and are not intended to limit the present invention.

[0090] Various combinations or partial combinations of the specific features and aspects of the embodiments disclosed above may be made and may still fall within the scope of one or more of the present invention. Furthermore, any specific features, aspects, methods, properties, characteristics, qualities, attributes, elements, etc. disclosed herein relating to an embodiment may be used in all other embodiments described herein. Therefore, it should be understood that various features and aspects of the disclosed embodiments may be combined with or substituted for each other to form various forms of the disclosed invention. Accordingly, it is intended that the scope of the present invention disclosed herein should not be limited by the specific disclosed embodiments described above. Furthermore, various modifications and alternative forms of the present invention are possible, specific examples of which are shown in the drawings and described in detail herein. However, it should be understood that the present invention is not limited to any specific form or method disclosed, but rather encompasses all modifications, equivalents, and alternatives that fall within the spirit and scope of the various embodiments described and the appended claims. The methods disclosed herein do not need to be performed in the order listed. The methods disclosed herein include specific actions performed by a practitioner. However, they may also include, explicitly or implicitly, instructions from any third party for those actions. For example, an action such as "unfolding a sterilized instrument using the system of this specification" includes "directing the unfolding of a sterilized instrument using the system of this specification." Furthermore, where a feature or aspect of this disclosure is described in relation to the Markush group, a person skilled in the art will recognize that this disclosure also describes any individual member or subgroup of members of the Markush group.

[0091] The scope disclosed herein also includes all overlaps, sub-scopes, and combinations thereof. Words such as “up to,” “at least,” “greater than,” “less than,” and “between” include the listed numbers. Numbers preceded by terms such as “about” or “approximately” include the listed numbers. For example, “about 10 nanometers” includes “10 nanometers.”

[0092] Any titles or subheadings used herein are for organizational purposes only and should not be used to limit the scope of the embodiments disclosed herein.

[0093] As used herein, the terms “approximately,” “about,” and “substantially” refer to quantities or characteristics close to the stated quantity or characteristic, which still perform the desired function or achieve the desired result. For example, in certain embodiments, the terms “approximately,” “about,” and “substantially” may refer to quantities within the range of plus or minus 10%, plus or minus 5%, plus or minus 1%, plus or minus 0.1%, and plus or minus 0.01% of the stated quantity or characteristic.

[0094] Exemplary Embodiments Embodiment 1: A neurovascular catheter for insertion into a patient's internal carotid artery, The neurovascular catheter has an elongated, flexible body that is less than approximately 110 cm in length. The elongated, flexible body is • It has a flexible distal portion that includes a length between approximately 10 cm and approximately 18 cm. The flexible distal portion is -A distal tip configured to be positioned within the cavernous segment of the internal carotid artery, - A transitional portion proximal to the distal tip, having lower flexibility than the distal tip, wherein the transitional portion is configured to be located within the petrous segment of the internal carotid artery. - A support portion proximal to the transition portion, having lower flexibility than the transition portion, wherein the support portion is configured to extend proximal to the base of the patient's skull, A neurovascular catheter equipped with the following features.

[0095] Embodiment 2: The catheter of Embodiment 1, wherein the elongated flexible body has a length between approximately 98 cm and approximately 102 cm.

[0096] Embodiment 3: The catheter of Embodiment 1 or 2, wherein the flexible distal portion has a length between approximately 12 cm and approximately 16 cm.

[0097] Embodiment 4: A catheter according to any of Embodiments 1 to 3, wherein the distal tip has a hardness between approximately 40A and approximately 73A.

[0098] Embodiment 5: A catheter according to any of Embodiments 1 to 4, wherein the distal tip has a length between approximately 15 mm and approximately 20 mm.

[0099] Embodiment 6: A catheter according to any of Embodiments 1 to 5, wherein the distal tip has a length between approximately 10 mm and approximately 20 mm.

[0100] Embodiment 7: A catheter according to any of Embodiments 1 to 6, wherein the transition portion includes urethane.

[0101] Embodiment 8: A catheter according to any of Embodiments 1 to 7, wherein the transition portion has a length between approximately 1.0 cm and 3.5 cm.

[0102] Embodiment 9: A catheter according to any of Embodiments 1 to 8, wherein the proximal end of the transition portion is positioned at a distance of approximately 5.5 cm to approximately 7.5 cm from the distal end of the flexible distal portion.

[0103] Embodiment 10: A catheter according to any of Embodiments 1 to 9, wherein at least a portion of the support portion includes a durometer in the range of 35D to 72D.

[0104] Embodiment 11: A catheter according to any of Embodiments 1 to 10, wherein the support portion comprises a polymer block amide.

[0105] Embodiment 12: A catheter according to any of Embodiments 1 to 11, wherein the distal tip has a constant rigidity along the length of the distal tip.

[0106] Embodiment 13: The catheter of Embodiment 12, wherein the rigidity is between approximately 20 gF and approximately 30 gF.

[0107] Embodiment 14: A catheter according to any of Embodiments 1 to 13, wherein the flexible distal portion further comprises a flexible portion that extends proximal to the distal tip and has increasing rigidity along the length of the flexible portion.

[0108] Embodiment 15: The catheter of Embodiment 12, wherein the flexible portion has a first rigidity at the first end of the flexible portion, where the rigidity is between approximately 20 gF and approximately 30 gF, and the flexible portion has a second rigidity at the second end of the flexible portion, where the rigidity is between approximately 60 gF and approximately 65 gF.

[0109] Embodiment 16: A catheter according to any of Embodiments 1 to 15, wherein the transition portion includes a constant rigidity along the length of the distal tip.

[0110] Embodiment 17: The catheter of Embodiment 16, wherein the rigidity is between approximately 50 gF and approximately 70 gF.

[0111] Embodiment 18: A catheter according to any of Embodiments 1 to 17, wherein the support portion includes increasing rigidity along the length of the support portion.

[0112] Embodiment 19: The catheter of Embodiment 18, wherein the support portion has a first rigidity at the first end of the support portion, which is between approximately 60 gF and approximately 70 gF, and the support portion has a second rigidity at the second end of the support portion, which is at least 400 gF.

[0113] Embodiment 20: A method for accessing a patient's cone-cavernosal segment, wherein the cone-cavernosal segment includes a length between 2.9 cm and 5.4 cm. The method is, The step of providing a catheter comprising an elongated flexible body and a flexible distal portion having a distal tip, a transition portion, and a support portion, The procedure involves advancing the distal tip of the catheter into the patient's internal carotid artery until the distal tip of the flexible distal portion is positioned within the cavernous segment of the internal carotid artery, a transitional portion located proximal to the distal tip and less flexible than the distal tip is positioned within the pyramidal segment of the internal carotid artery, and a supporting portion located proximal to the transitional portion and less flexible than the transitional portion extends from the base of the patient's skull. Methods that include...

[0114] Embodiment 21: The method of Embodiment 20, wherein the distal tip of the guide catheter is inserted until tactile feedback is received at the proximal end of the elongated flexible body indicating that the transition portion has engaged with the anatomical structure of the pyramidal segment.

[0115] Embodiment 22: The method of Embodiments 20-21, wherein the elongated flexible body includes a length of less than 110 cm.

[0116] Embodiment 23: Any method of Embodiments 20 to 22, wherein the elongated flexible body includes a length of 100 cm.

[0117] Embodiment 24: The method of Embodiment 20, wherein the flexible distal portion includes a length between 14 cm and 18 cm.

[0118] Embodiment 25: The method of Embodiment 20, wherein the flexible distal portion includes a length of 14 cm.

[0119] Embodiment 26: The method of Embodiment 20, wherein the transition portion includes a length between approximately 1.0 cm and approximately 3.5 cm.

[0120] Embodiment 27: The method of Embodiment 20, wherein the proximal end of the transition portion is positioned at a distance of 6.5 cm from the distal end of the flexible distal portion.

[0121] Embodiment 28: The method of Embodiment 20, wherein the distal tip portion includes a length of 17 mm.

[0122] Embodiment 29: The method of Embodiment 20, wherein the distal tip is more flexible than the transition portion, and the transition portion is more flexible than the support portion.

[0123] Embodiment 30: The method of Embodiment 20, configured to treat tandem lesions.

[0124] Embodiment 31: A neurovascular catheter for insertion into a patient's internal carotid artery, wherein the neurovascular catheter is It has a long, slender, flexible body that is less than approximately 110 cm in length. The elongated flexible body includes a flexible distal segment with a length ranging from approximately 10 cm to approximately 18 cm. The flexible distal segment is -A distal portion having a length between approximately 20 mm and approximately 40 mm, the distal portion is A tracking tip configured to be positioned within the cavernous segment of the internal carotid artery, wherein the tracking tip has a length between approximately 10 mm and approximately 20 mm. • A stiffening portion proximal to the tip of the tracking end, wherein the stiffening portion has a length between approximately 5 mm and approximately 15 mm. The distal portion, including, -A proximal transition portion of the distal portion, having lower flexibility than the tracking tip, wherein the transition portion is configured to be positioned within the petrous segment of the internal carotid artery, and the transition portion has a length of approximately 30 mm to approximately 40 mm. - A support portion proximal to the transition portion, having lower flexibility than the transition portion, wherein the support portion is configured to extend proximal to the base of the patient's skull, and the support portion includes rigidity that increases proximal along the length of the support portion, and the support portion has a length between approximately 70 mm and approximately 80 mm. Equipped with, The flexibility profile of the flexible distal segment can be measured using a cantilever beam test with a gauge length of 5 mm and a displacement of 4 mm to determine the peak load value. The peak load value at the tracking tip is between approximately 10gF and approximately 30gF. The peak load value in the section where stiffness increases increases from approximately 20gF to approximately 30gF over the length of the section where stiffness increases, to approximately 50gF to approximately 70gF. The peak load value in the transitional portion is between approximately 50gF and approximately 70gF. A neurovascular catheter having a peak load value at the first end of the support portion between approximately 50 gF and approximately 70 gF, and a peak load value at the second end of the support portion at least approximately 400 gF.

[0125] Embodiment 32: A neurovascular catheter according to Embodiment 31, wherein the elongated flexible body has a length of approximately 100 cm.

[0126] Embodiment 33: A neurovascular catheter according to any of Embodiments 31 to 32, wherein the flexible distal segment has a length of approximately 14 cm.

[0127] Embodiment 34: A neurovascular catheter according to any of Embodiments 31 to 33, wherein the distal portion has a length of approximately 30 mm.

[0128] Embodiment 35: A neurovascular catheter according to any of Embodiments 31 to 34, having a tracking tip approximately 17 mm in length.

[0129] Embodiment 36: A neurovascular catheter according to any of Embodiments 31 to 35, wherein the rigidity-enhancing portion has a length of approximately 13 mm.

[0130] Embodiment 37: A neurovascular catheter according to any of Embodiments 31 to 36, wherein the transition portion has a length of approximately 35 mm.

[0131] Embodiment 38: A neurovascular catheter according to any of Embodiments 31 to 37, wherein the support portion has a length of approximately 75 mm.

[0132] Embodiment 39: A neurovascular catheter for insertion into a patient's internal carotid artery, wherein the neurovascular catheter is A flexible distal segment of a neurovascular catheter for insertion into the patient's internal carotid artery is provided. The flexible distal segment is -The distal part, • A tracking tip configured to be positioned within the cavernous segment of the internal carotid artery, • Parts with increased rigidity, A distal portion comprising, - A transitional portion configured to be located within the pyramidal segment of the internal carotid artery, - A support portion configured to extend proximal to the base of the patient's skull, Equipped with, The flexibility profile of the flexible distal segment can be measured using a cantilever beam test with a gauge length of 5 mm and a displacement of 4 mm to determine the peak load value. The peak load value at the tracking tip is less than approximately 30 gF. The peak load value in the stiffness-increasing section increased from approximately 20gF to approximately 30gF over the length of the stiffness-increasing section to approximately 50gF to approximately 70gF. The peak load value in the transitional portion is between approximately 50gF and approximately 70gF. A neurovascular catheter having a peak load value at the first end of the support portion between approximately 50 gF and approximately 70 gF, and a peak load value at the second end of the support portion at least approximately 400 gF.

[0133] Embodiment 40: The neurovascular catheter of Embodiment 39, wherein the flexible distal segment has a length between approximately 10 cm and approximately 18 cm.

[0134] Embodiment 41: A neurovascular catheter according to any of Embodiments 39 to 40, wherein the flexible distal segment has a length of approximately 14 cm.

[0135] Embodiment 42: A neurovascular catheter according to any of Embodiments 39 to 41, wherein the distal portion has a length between approximately 20 mm and approximately 40 mm.

[0136] Embodiment 43: A neurovascular catheter according to any of Embodiments 39 to 42, wherein the distal portion has a length of approximately 30 mm.

[0137] Embodiment 44: A neurovascular catheter according to any of Embodiments 39 to 43, wherein the tracking tip has a length between approximately 10 mm and approximately 20 mm.

[0138] Embodiment 45: The neurovascular catheter of Embodiment 44, wherein the tracking tip has a length of approximately 17 mm.

[0139] Embodiment 46: A neurovascular catheter according to any of Embodiments 39 to 45, wherein the rigidity-enhancing portion has a length between approximately 5 mm and approximately 15 mm.

[0140] Embodiment 47: The neurovascular catheter of Embodiment 46, wherein the rigidity-enhancing portion has a length of approximately 13 mm.

[0141] Embodiment 48: A neurovascular catheter according to any of Embodiments 39 to 47, wherein the transition portion has a length between approximately 30 mm and approximately 40 mm.

[0142] Embodiment 49: The neurovascular catheter of Embodiment 48, wherein the transition portion has a length of approximately 35 mm.

[0143] Embodiment 50: A neurovascular catheter according to any of Embodiments 39 to 49, wherein the support portion has a length between approximately 70 mm and approximately 80 mm.

[0144] Embodiment 51: A neurovascular catheter according to Embodiment 50, wherein the support portion has a length of approximately 75 mm.

[0145] Embodiment 52: A method for accessing the cone-cavernous segment of a patient, The method is, - A step of providing a catheter comprising a flexible distal segment having a tracking tip and a rigidity-enhancing portion, a transition portion and a support portion, - A step of advancing the flexible distal segment of the catheter into the patient's internal carotid artery, thereby, The tracking tip of the flexible distal segment is located within the cavernous segment of the internal carotid artery. The transitional portion is located within the petrous segment of the internal carotid artery. • The support portion extends to the base of the patient's skull. Steps and Methods that include...

[0146] Embodiment 53: The method of Embodiment 52, wherein the tracking tip of the flexible distal segment of the catheter is inserted until tactile feedback is received at the proximal end of the catheter indicating that the transition portion has engaged with the anatomical structure of the pyramidal segment.

[0147] Embodiment 54: Any method of Embodiments 52 to 53, wherein the catheter has a length of less than 110 cm.

[0148] Embodiment 55: Any method according to Embodiments 52 to 54, wherein the catheter has a length of 100 cm.

[0149] Embodiment 56: The method according to any of Embodiments 52 to 55, wherein the flexible distal segment has a length between 10 cm and 18 cm.

[0150] Embodiment 57: The method according to any of Embodiments 52 to 56, wherein the flexible distal segment has a length of 14 cm.

[0151] Embodiment 58: The method according to any of Embodiments 52 to 57, wherein the distal portion has a length between approximately 20 mm and 40 mm.

[0152] Embodiment 59: Any method according to Embodiments 52 to 58, wherein the distal portion has a length of approximately 30 mm.

[0153] Embodiment 60: Any method according to Embodiments 52 to 59, wherein the tracking tip has a length between approximately 10 mm and approximately 20 mm.

[0154] Embodiment 61: Any method of Embodiments 52 to 60, wherein the tracking tip has a length of approximately 17 mm.

[0155] Embodiment 62: Any method of Embodiments 52 to 61, wherein the rigidity-enhancing portion has a length between approximately 5 mm and approximately 15 mm.

[0156] Embodiment 63: Any method of Embodiments 52 to 62, wherein the rigidity-enhancing portion has a length of approximately 13 mm.

[0157] Embodiment 64: Any method of Embodiments 52 to 63, wherein the transition portion has a length between approximately 30 mm and approximately 40 mm.

[0158] Embodiment 65: Any method of Embodiments 52 to 64, wherein the transition portion has a length of approximately 35 mm.

[0159] Embodiment 66: Any method of Embodiments 52 to 65, wherein the support portion has a length between approximately 70 mm and approximately 80 mm.

[0160] Embodiment 67: Any method of Embodiments 52 to 66, wherein the support portion has a length of approximately 75 mm.

[0161] Embodiment 68: Any method according to Embodiments 52 to 67, wherein the distal tip is more flexible than the transition portion, and the transition portion is more flexible than the support portion.

[0162] Embodiment 69: Any method from Embodiments 52 to 68 configured to treat a tandem lesion.

[0163] Embodiment 70: The flexibility profile of the flexible distal segment can be measured in a cantilever beam test using a gauge length of 5 mm and a displacement of 4 mm to determine the peak load value. The peak load value at the tracking tip is between approximately 10gF and approximately 30gF. The peak load value in the stiffness-increasing section increased from approximately 20gF to approximately 30gF over the length of the stiffness-increasing section to approximately 50gF to approximately 70gF. The peak load value in the transitional portion is between approximately 50gF and approximately 70gF. The peak load value at the first end of the support portion is between approximately 50gF and approximately 70gF, and the peak load value at the second end of the support portion is at least approximately 400gF. Any method according to Embodiments 52 to 69. [Explanation of Symbols]

[0164] 40 Soft lock, 100 Catheter, 110 Transition segment, 120 Proximal segment, 130 Flexible distal segment, 140 Support section, 151 Proximal end, 200 Introduction sheath, 222 Transition guide sheath, 224 Insertion catheter, 230 Transition guidewire, 232 First guidewire, 300 Femoral artery, 310 Aortic arch, 340 Brain segment, 350 Cavernous segment, 360 Brachiocephalic artery, 370 Pyramidal segment, 400 Thrombus, 1000 Catheter, 1100 Flexible distal segment, 1110 Transition segment, 1120 Proximal segment, 1122 Distal end, 1126 Guidewire, 1128 Aspiration catheter, 1140 Soft lock, 1210 Tracking tip, 1216 Origin, 1220 Increased rigidity section, 1300 Transitional segment, 1400 Supporting segment, 1500 Proximal segment, 1510 Proximal end, 2000 Flexible profile, 2100 Section, 2200 Section, 2200a Section, 2200b Section, 2200c Section, 2300 Section, 2400 Section, 3000 Tandem lesion

Claims

1. A neurovascular catheter for insertion into the internal carotid artery of a patient, The neurovascular catheter comprises an elongated, flexible body with a length of less than approximately 110 cm. The aforementioned elongated flexible body includes a flexible distal portion having a length between approximately 10 cm and approximately 18 cm. The aforementioned flexible distal portion is The distal tip is configured to be positioned within the cavernous segment of the internal carotid artery, A transitional portion proximal to the distal tip, having lower flexibility than the distal tip, wherein the transitional portion is configured to be located within the petrous segment of the internal carotid artery, A support portion proximal to the transition portion, having lower flexibility than the transition portion, wherein the support portion is configured to extend proximal to the base of the patient's skull, A neurovascular catheter equipped with the following features.

2. The catheter according to claim 1, wherein the elongated flexible body has a length between approximately 98 cm and approximately 102 cm.

3. The catheter according to claim 1, wherein the flexible distal portion has a length between approximately 12 cm and approximately 16 cm.

4. The catheter according to claim 1, wherein the distal tip portion has a length between approximately 15 mm and approximately 20 mm.

5. The catheter according to claim 1, wherein the transition portion has a length between approximately 1.0 cm and approximately 3.5 cm.

6. The catheter according to claim 1, wherein the proximal end of the transition portion is positioned at a distance of approximately 5.5 cm to approximately 7.5 cm from the distal end of the flexible distal portion.

7. The catheter according to claim 1, wherein the distal tip portion has a certain rigidity along the length of the distal tip portion.

8. The catheter according to claim 7, wherein the stiffness is between approximately 20 gF and approximately 30 gF, and the stiffness is determined using a cantilever beam test with a gauge length of 5 mm and a displacement of 4 mm to determine the peak load value.

9. The aforementioned flexible distal portion further includes a flexible portion, The catheter according to claim 1, wherein the flexible portion extends proximal to the distal tip and has rigidity that increases along the length of the flexible portion.

10. The catheter according to claim 9, wherein the flexible portion has a first rigidity at a first end of the flexible portion, where the rigidity is between approximately 20 gF and approximately 30 gF, and the flexible portion has a second rigidity at a second end of the flexible portion, where the rigidity is between approximately 60 gF and approximately 65 gF.

11. The catheter according to claim 1, wherein the transition portion includes a certain rigidity along the length of the distal tip.

12. The catheter according to claim 11, wherein the rigidity is between approximately 50 gF and approximately 70 gF.

13. The catheter according to claim 1, wherein the support portion includes rigidity that increases along the length of the support portion.

14. The catheter according to claim 13, wherein the support portion has a first rigidity at a first end of the support portion, which is between approximately 60 gF and approximately 70 gF, and the support portion has a second rigidity at a second end of the support portion, which is at least 400 gF.

15. A neurovascular catheter for insertion into the internal carotid artery of a patient, The neurovascular catheter comprises an elongated, flexible body with a length of less than approximately 110 cm. The aforementioned elongated flexible body is A flexible distal segment having a length between approximately 10 cm and approximately 18 cm, wherein the flexible distal segment is - A distal portion having a length between approximately 20 mm and 40 mm, wherein the distal portion is - A tracking tip configured to be positioned within the cavernous segment of the internal carotid artery, wherein the tracking tip has a length between approximately 10 mm and approximately 20 mm. - The stiffness-enhancing portion proximal to the tracking tip, wherein the stiffness-enhancing portion has a length between approximately 5 mm and approximately 15 mm. The distal portion, including, - A proximal transition portion of the distal portion having lower flexibility than the tracking tip, wherein the transition portion is configured to be positioned within the pyramidal segment of the internal carotid artery, and the transition portion has a length between approximately 30 mm and approximately 40 mm. - A support portion proximal to the transition portion, having lower flexibility than the transition portion, wherein the support portion is configured to extend proximal to the base of the patient's skull, the support portion has rigidity that increases proximal to the length of the support portion, and the support portion has a length between approximately 70 mm and approximately 80 mm. Equipped with, The flexibility profile of the aforementioned flexible distal segment can be measured using a cantilever beam test with a gauge length of 5 mm and a displacement of 4 mm to determine the peak load value. The peak load value at the tracking tip is less than approximately 30 gF. The peak load value in the portion where the stiffness increases increases from between approximately 20 gF and approximately 30 gF to between approximately 50 gF and approximately 70 gF over the length of the portion where the stiffness increases. The peak load value in the transition portion is between approximately 50 gF and approximately 70 gF. A neurovascular catheter in which the peak load value at the first end of the support portion is between approximately 50 gF and approximately 70 gF, and the peak load value at the second end of the support portion is at least approximately 400 gF.

16. The neurovascular catheter according to claim 15, wherein the elongated flexible body has a length of approximately 100 cm.

17. The neurovascular catheter according to claim 15, wherein the flexible distal segment has a length of approximately 14 cm.

18. The neurovascular catheter according to claim 15, wherein the distal portion has a length of approximately 30 mm.

19. The neurovascular catheter according to claim 15, wherein the tracking tip has a length of approximately 17 mm.

20. The neurovascular catheter according to claim 15, wherein the rigidity-enhancing portion has a length of approximately 13 mm.

21. The neurovascular catheter according to claim 15, wherein the transition portion has a length of approximately 35 mm.

22. The neurovascular catheter according to claim 15, wherein the support portion has a length of approximately 75 mm.

23. A neurovascular catheter for insertion into the internal carotid artery of a patient, The neurovascular catheter comprises a flexible distal segment for insertion into the patient's internal carotid artery. The aforementioned flexible distal segment is • The distal part, - A tracking tip configured to be positioned within the cavernous segment of the internal carotid artery, - The part with increased rigidity, A distal portion comprising, - A transitional portion configured to be located within the pyramidal segment of the internal carotid artery, - A support portion configured to extend proximal to the base of the patient's skull, Equipped with, The flexibility profile of the aforementioned flexible distal segment can be measured using a cantilever beam test with a gauge length of 5 mm and a displacement of 4 mm to determine the peak load value. The peak load value at the tracking tip is less than approximately 30 gF. The peak load value in the stiffness-increased portion increases from between approximately 20 gF and approximately 30 gF to between approximately 50 gF and approximately 70 gF over the length of the stiffness-increased portion. The peak load value in the transition portion is between approximately 50 gF and approximately 70 gF. A neurovascular catheter in which the peak load value at the first end of the support portion is between approximately 50 gF and approximately 70 gF, and the peak load value at the second end of the support portion is at least approximately 400 gF.

24. The neurovascular catheter according to claim 23, wherein the flexible distal segment has a length between approximately 10 cm and approximately 18 cm.

25. The neurovascular catheter according to claim 23, wherein the distal portion has a length between approximately 20 mm and 40 mm.

26. The neurovascular catheter according to claim 23, wherein the tracking tip has a length between approximately 10 mm and approximately 20 mm.

27. The neurovascular catheter according to claim 23, wherein the rigidity-enhancing portion has a length between approximately 5 mm and approximately 15 mm.

28. The neurovascular catheter according to claim 23, wherein the transition portion has a length between approximately 30 mm and approximately 40 mm.

29. The neurovascular catheter according to claim 23, wherein the support portion has a length between approximately 70 mm and approximately 80 mm.

30. A method for accessing the cone-cavernous segment of a patient, the method being: - A step of providing a catheter having a flexible distal segment comprising a distal portion having a tracking tip and a rigidity-enhancing portion, a transition portion and a support portion, - A step of advancing the flexible distal segment of the catheter into the patient's internal carotid artery, thereby, - The tracking tip of the flexible distal segment is positioned within the cavernous segment of the internal carotid artery. - The transition portion is located within the pyramidal segment of the internal carotid artery, - The support portion extends to the base of the patient's skull. Steps and Methods that include...

31. The method according to claim 30, wherein the tracking tip of the flexible distal segment of the catheter is inserted until tactile feedback is received at the proximal end of the catheter indicating that the transition portion has engaged with the anatomical structure of the pyramidal segment.

32. The method according to claim 30, wherein the catheter has a length of less than 110 cm.

33. The method according to claim 30, wherein the catheter has a length of 100 cm.

34. The method according to claim 30, wherein the flexible distal segment has a length between 10 cm and 18 cm.

35. The method according to claim 30, wherein the flexible distal segment has a length of 14 cm.

36. The method according to claim 30, wherein the distal portion has a length between approximately 20 mm and approximately 40 mm.

37. The method according to claim 30, wherein the distal portion has a length of approximately 30 mm.

38. The method according to claim 30, wherein the tracking tip has a length between approximately 10 mm and approximately 20 mm.

39. The method according to claim 30, wherein the tracking tip has a length of approximately 17 mm.

40. The method according to claim 30, wherein the rigidity-enhancing portion has a length between approximately 5 mm and approximately 15 mm.

41. The method according to claim 30, wherein the rigidity-enhancing portion has a length of approximately 13 mm.

42. The method according to claim 30, wherein the transition portion has a length between approximately 30 mm and approximately 40 mm.

43. The method according to claim 30, wherein the transition portion has a length of approximately 35 mm.

44. The method according to claim 30, wherein the support portion has a length between approximately 70 mm and approximately 80 mm.

45. The method according to claim 30, wherein the support portion has a length of approximately 75 mm.

46. The method according to claim 30, wherein the distal tip is more flexible than the transition portion, and the transition portion is more flexible than the support portion.

47. The method according to claim 30, configured to treat a tandem lesion.

48. The flexibility profile of the aforementioned flexible distal segment can be measured using a cantilever beam test with a gauge length of 5 mm and a displacement of 4 mm to determine the peak load value. The peak load value at the tracking tip is less than approximately 30 gF. The peak load value in the stiffness-increased portion increases from between approximately 20 gF and approximately 30 gF to between approximately 50 gF and approximately 70 gF over the length of the stiffness-increased portion. The peak load value in the transition portion is between approximately 50 gF and approximately 70 gF. The peak load value at the first end of the support portion is between approximately 50 gF and approximately 70 gF, and the peak load value at the second end of the support portion is at least approximately 400 gF. The method according to claim 30.

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