Catheter

Abstract

A catheter whose stiffness is reduced (i.e., increased flexibility) toward the distal end of the catheter and then further increased (i.e., reduced flexibility) toward the distal end. Thus, the distal portion of the catheter, including its distal end, may have greater stiffness than the penultimate distal portion of the catheter proximate the proximal end of the distal portion. The penultimate distal end portion may have a substantially uniform stiffness prior to transitioning to the penultimate proximal end portion, wherein the stiffness gradually increases. The penultimate proximal portion may transition to a proximal portion having a substantially uniform stiffness that is greater than the stiffness of the remaining portions. The manner in which stiffness varies along the length of the catheter may vary, including but not limited to various characteristics of an outer sheath, a coil, a braided tubular mesh layer, an inner coil, and / or a radiopaque marker, etc.

Description

Background Art

[0001] A catheter is an elongated medical device used to access and / or assist in treating internal locations within a patient's body, such as blood vessels or other cavities. In some cases, a catheter is advanced through a patient's blood vessel. Generally, such a catheter may need to be of a relatively long length to reach a desired target location within the patient's body. Depending on the purpose, the diameter of such a catheter may be relatively small or may need to be relatively large.

[0002] In either case, it is generally desirable for the catheter to be flexible enough to pass through tortuous blood vessel passages without damaging the blood vessels and to have good "pushability", allowing forward movement and twisting without kinking or otherwise damaging the catheter. In this regard, finding the right balance of rigidity and flexibility can sometimes vary depending on the length and diameter of the catheter required for a particular use. Summary of the Invention

[0003] This specification generally relates to the structural features of a catheter. Specifically, the structural features provide desirable flexibility and pushability while reducing kinking.

[0004] One aspect of this specification relates to a catheter that decreases in stiffness (i.e., increases in flexibility) towards the distal end of the catheter and then increases in stiffness (i.e., decreases in flexibility) towards a further distal end. For example, the distal region of the catheter may have a reduced stiffness at the distal end but an increased stiffness near or closest to the distal end of the catheter.

[0005] In one example, the catheter may include a distal region that includes a first region (e.g., length) of the catheter and a second region (e.g., length) located distal to the first region, the first region having a single flexibility of a first value and the second region having a single flexibility of a second value, the second value being lower than the first value (i.e., stiffer than the first value).

[0006] In another example, the catheter may include a first region (e.g., the length of the catheter) that gradually increases in flexibility (i.e., decreases in stiffness) towards the distal end. In this regard, the proximal end of the first region has a lower flexibility than the distal end of the first region. A second region (e.g., the length of the catheter) may be located distal to the first region and have a uniform flexibility or a gradually increasing flexibility towards the distal end. In either case of the second region, at least a portion of the second region will have a lower flexibility than the lowest flexibility of the first region. For example, if the second region has a uniform flexibility, its flexibility may be lower than one or all of the distal, middle, or proximal ends of the first region. If the flexibility of the second region gradually decreases, the flexibility at one or all positions within the second region may be lower than one or all of the distal, middle, or proximal ends of the first region.

[0007] In another example, a catheter can include at least a proximal portion (i.e., the most proximal portion), a penultimate distal portion (i.e., the second most distal portion), and a distal portion (i.e., the most distal portion). Each of the proximal portion, the penultimate distal portion, and / or the distal portion can have a uniform stiffness and / or can have a variable stiffness along at least a portion of their respective lengths. The penultimate distal portion can be located between the proximal portion and the distal portion. The distal portion can have a greater stiffness than the penultimate distal portion such that the stiffness of the distal tip of the catheter can be greater than at least a portion of the penultimate distal portion.

[0008] In another example, a catheter can include at least a distal portion, a penultimate distal portion, a penultimate proximal portion (i.e., the second most proximal portion), and a proximal portion. The stiffness of the distal portion can be greater than the stiffness of the penultimate distal portion. The stiffness of the penultimate proximal portion can be greater than the stiffness of the penultimate distal portion and the stiffness can increase gradually along the length of the penultimate proximal portion. The stiffness of the proximal portion can be substantially uniform.

[0009] The flexibility / stiffness of the catheter, particularly the distal region of the catheter, can be determined by one or more of the following features.

[0010] In a first example, the stiffness of the outer sheath or cannula of the catheter can consist of regions of different hardness or flexibility. The outer sheath can have a plurality of discrete segments or regions composed of materials of different hardness and / or flexibility. This can be achieved by using different materials for different segments / regions and / or different thicknesses for different segments / regions. Alternatively, the outer sheath can be formed from a single continuous segment / region with a varying hardness and / or flexibility (e.g., by mixing materials in different regions during the formation or extrusion of the tubular outer sheath, or by increasing or decreasing the thickness of the sheath in different regions).

[0011] In a second example, the stiffness / flexibility of the catheter can be altered by changing the characteristics of a coil located within the catheter wall (e.g., beneath the outer sheath) and extending at least through the distal region of the catheter. The spacing between individual coils can be increased to increase flexibility and decreased to reduce flexibility. As an alternative or in addition, the thickness / diameter of the wire can be increased to reduce flexibility and also decreased to reduce flexibility. Thus, the spacing in the coil can initially increase distally and then decrease, and / or the diameter of the wire can initially decrease distally and then increase. Alternatively or additionally, the coil can be composed of two or more materials with different flexibilities that can be joined together (e.g., by welding, etc.) such that the flexibility changes along the length of the coil.

[0012] In a third example, the stiffness / flexibility of the catheter can be altered by changing the characteristics of a braided wire tubular layer located within the catheter wall (e.g., between an outer sheath and an inner coil, or below the inner coil). The braided wire can increase the weft density to reduce flexibility and decrease the weft density to increase flexibility. Alternatively or additionally, the wires forming the braided wire can increase in thickness to reduce flexibility or decrease in thickness to increase flexibility. Alternatively or additionally, the braided wire tubular layer can be composed of two or more materials having different flexibilities, which can be braided together to vary the flexibility along the length of the braided wire tubular section. Alternatively or additionally, the braided wire tubular layer can utilize two or more braided patterns having different flexibilities in order to vary the flexibility along the length of the braided wire tubular section.

[0013] In a fourth example, the stiffness / flexibility of the catheter can be altered by changing the characteristics of a catheter liner that forms the lumen of the catheter or the passageway between its proximal and distal ends. The liner can be formed from two or more tubular sections that include materials of different hardnesses or flexibilities. In some examples, the liner can be formed from a first tubular section of a first material (e.g., PTFE) and a second tubular section that is connected to the distal end of the first tubular section and is formed from a second material (e.g., polyolefin elastomer) that is softer or more flexible than the first material. In another example, a third tubular section can be connected to the distal end of the second tubular section and can be composed of the first material or a different third material that is harder or less flexible than the second material. In another example, the liner can not have discrete connected tubular sections but can be formed as a single tubular member that gradually changes in hardness or flexibility, such as by gradually varying the amount or combination of different materials having different hardnesses or by varying the thickness of the liner in various regions (e.g., thinner regions have greater flexibility relative to thicker regions).

[0014] In a fifth example, a radiopaque marker can extend from the distal end of the catheter to form a distal tip. The radiopaque marker can be integral with or attached to the catheter body. The radiopaque marker can be composed of a material having a greater hardness or less flexibility than the hardness or flexibility of the second most distal portion of the catheter from which the radiopaque marker extends.

[0015] In a sixth example, the distal portion or distal tip can be constructed in part using a polymer blend or resin in which a radiopaque material, such as barium sulfate or tantalum, is mixed. The radiopaque material can be added to the polymer blend or resin before or during an extrusion step. This can impart radiopaque characteristics to the distal portion or distal tip, allowing the user or operator to visualize the catheter tip during use without significantly altering the material properties (e.g., stiffness, hardness) of the distal portion or tip of the catheter. Description of the Drawings

[0016] These and other aspects, features, and advantages that can be achieved by the embodiments of the present invention will become apparent and be elucidated from the following description of the embodiments of the present invention, with reference to the accompanying drawings, in which:

[0017] Figure 1 is a side view of a catheter according to an example.

[0018] Figure 2 is according to an example Figure 1 side view of the catheter lining.

[0019] Figure 3 is according to an example Figure 1 side view of the coil layer of the catheter.

[0020] Figure 4 is according to an example Figure 1 side view of the braided layer of the catheter.

[0021] Figure 5 is according to an example Figure 1 side view of the outer sheath of the catheter.

[0022] Figure 6 is according to an example Figure 1 side view of the catheter interface of the catheter.

[0023] Figure 7 is a perspective cross-sectional view showing the braided layer and the outer sheath layer of the catheter according to an example Figure 1 of the catheter.

[0024] Figure 8 is a catheter stiffness diagram according to an example.

[0025] Figure 9 is a catheter stiffness diagram according to an example.

[0026] Figure 10 is a catheter stiffness diagram according to an example.

[0027] Figure 11 is a catheter stiffness diagram according to an example.

[0028] Figure 12 is a catheter stiffness diagram according to an example.

[0029] Figure 13 is a catheter stiffness diagram according to an example.

[0030] Figure 14 Shows type I, type II, and type III aortic arches. Detailed Description

[0031] Specific embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments described herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The terms used in the detailed description of the embodiments shown in the drawings are not intended to limit the present invention. In the drawings, the same numbers represent the same elements.

[0032] Although different embodiments and examples may be described in this specification, it is specifically contemplated that any features from different embodiments and examples can be combined in any combination. In other words, the features of different embodiments and examples can be mixed and matched with each other. Thus, although every permutation of features from different embodiments and examples may not be explicitly shown, it is the intention of this specification to cover any such combination.

[0033] The terms stiffness, hardness, and flexibility are used in this specification to describe the characteristics of a catheter. Generally, as stiffness or hardness increases, flexibility decreases. Thus, although one of these terms may be used at different points in this specification, the relationship between the other terms should also be understood.

[0034] The terms "distal" and "proximal" are used in this specification. The distal end generally refers to the direction or region toward or near the working end of the catheter (e.g., the end advanced to the target location within a patient). The proximal end generally refers to the direction or region near the patient and / or the doctor.

[0035] The terms segment, region, and portion are used throughout this specification and generally refer to a certain axial length of the catheter or along its axial length.

[0036] This specification generally relates to the structural features of a catheter. Specifically, the structural features provide desirable flexibility and pushability while reducing kinking.

[0037] The structural features and other aspects of this specification can be applied to catheters of any type, size, and / or use within the human body.

[0038] One example type of catheter that can benefit from the structural features and other aspects described in this specification is the so-called "88" catheter or a catheter having an inner lumen passage with a diameter of approximately 0.088 inches. Currently, such catheters are likely to be among the larger lumen diameter catheters used for stroke treatment (e.g., compared to 5 French (1.667 mm) and 6 French (2 mm) catheters), and are often used as access catheters for clot treatment, removal, or thrombectomy. For certain uses, the relatively large lumen diameter allows a balloon catheter or a clot retrieval device to be advanced through the lumen of the catheter to the desired location so that the clot can be disrupted, engaged, and retrieved into the lumen. Thus, the larger diameter may help accommodate relatively large medical implants and / or devices such as balloon catheters, clot retrieval devices, and even the clot itself.

[0039] These larger lumens with a diameter of 0.088 inches may also help with aspirating clots. The distal tip of the catheter can be advanced near the clot, and suction / vacuum can be applied to the lumen of the catheter so that the clot is drawn into the lumen and removed from the patient's blood vessel. In addition to the example of the 0.088-inch diameter lumen, other sizes greater than 5 French or 6 French can also provide similar advantages and benefits, such as a catheter having an inner lumen passage with a diameter of 0.092 inches (2.3368 mm).

[0040] The middle cerebral artery (MCA) is the most common artery in acute stroke. It branches directly from the internal carotid artery and consists of four main branches, M1, M2, M3, and M4. These blood vessels supply blood to the frontal, temporal, and parietal parts of the brain, as well as deep structures such as the caudate nucleus, internal capsule, and thalamus. Due to its size and location, clots in the MCA M1 and M2 regions are most commonly treated with clot retrieval devices and / or aspiration, and thus the 0.088-inch lumen catheter helps provide optimal treatment for these regions.

[0041] To access the brain, doctors typically enter the patient's vascular system from the patient's lower limb (e.g., the femoral artery in the groin area). Radial artery access, such as near the patient's wrist, is also possible. In addition, the MCA and the blood vessels close to it tend to be relatively tortuous. Therefore, such a catheter should be relatively long, pushable without kinking, and should maintain the flexibility to navigate in the MCA, which can be difficult to achieve because greater flexibility tends to increase the risk of kinking. In addition, the larger 0.088-inch lumen catheters typically have a more robust structure and are thus sturdier because of their increased size and prevent their lumen from collapsing during use, especially under negative or vacuum pressure during aspiration. Therefore, it is difficult to provide a structure in these larger 0.088-inch lumen catheters that meets these structural and flexibility requirements.

[0042] In this regard, the present specification provides several different aspects of a catheter structure that may contribute to achieving a balance of flexibility and pushability in catheters of any size (e.g., 5 French and 6 French), particularly in a 0.088 size catheter.

[0043] One aspect of the present specification relates to a catheter that has a decreasing stiffness (i.e., increasing flexibility) towards the distal end of the catheter and then an increasing stiffness (i.e., decreasing flexibility) towards the distal end. For example, the distal region of the catheter generally has a decreasing stiffness at the distal end, but the stiffness increases near or closest to the distal end of the catheter such that the stiffness of the distal portion of the catheter is greater than the penultimate distal portion of the catheter in the proximal direction.

[0044] Typically, the proximal region of most catheters is relatively stiff and to some extent the stiffness decreases towards the distal end of the catheter. However, by decreasing the stiffness at the distal end and then increasing the stiffness near the distal end of the catheter, there may be certain advantages in certain applications.

[0045] For example, the region of decreasing stiffness can provide a higher flexibility for most of the distal region of the catheter, thus enabling maneuverability in tortuous vascular accesses, while the region of increasing stiffness closer to the distal end of the catheter can help prevent the collapse of the catheter lumen (e.g., under vacuum pressure, when abutting against the vessel sidewall, when turning in a tortuous vasculature, or when encountering a stenotic region), particularly for catheter use involving aspiration through its lumen.

[0046] In some cases, the region of increasing stiffness may also improve the performance of aspirating clots. For example, when pulling a clot through aspiration via the catheter lumen, the relatively stiff end region may better cut or remove the clot from the vessel. Additionally, the distal end of the catheter can better resist bending or applying suction to non-clot structures (e.g., a portion of a blood vessel). This may be particularly useful in relatively large-sized catheters (such as a 0.088-inch catheter), although other sized catheters may also benefit.

[0047] In the case of clearing blood clots in cerebral blood vessels such as the middle cerebral artery, the region of increasing catheter stiffness can better navigate through tortuous vascular accesses and branched vascular accesses. While the distal region generally remains relatively flexible, the increase in stiffness near the catheter tip may be beneficial for guiding the catheter to the desired branched or tortuous vascular regions. In other words, the additional increase in stiffness may help improve pushability without kinking near the distal end of the catheter.

[0048] A decrease in stiffness (relative to the proximal region of the catheter) and then an increase in stiffness along the distal region of the catheter may include different ways of quantifying, describing, or constructing such flexibility. In this regard, it should be noted that the distal region of the catheter can be considered as a separate, discrete region or length having a different stiffness / flexibility relative to adjacent regions, or the flexibility of the distal region can increase and / or decrease continuously. Thus, when referring to the flexibility / stiffness of different regions or lengths, these descriptions may include regions of uniform flexibility / rigidity or regions of average flexibility / stiffness.

[0049] In one example, a catheter can include a distal region that includes a first region (e.g., length) of the catheter and a second region (e.g., length) distal to the first region, the first region having a single flexibility of a first value and the second region having a single flexibility of a second value, the second value being lower than the first value (i.e., stiffer than the first value).

[0050] In one example, a catheter can include a proximal portion, a penultimate distal portion, and a distal portion. The penultimate distal portion can be located between the proximal portion and the distal portion. Thus, the penultimate distal portion can be distal relative to the proximal portion and proximal relative to the distal portion. The flexibility of each of the proximal, penultimate, and / or distal portions can be uniform along its respective length and / or variable along its respective length. The flexibility of the distal portion can be less than the flexibility of the penultimate distal portion such that the stiffness of the distal portion is greater than the stiffness of the distal portion.

[0051] In another example, a catheter can include a first region (e.g., the length of the catheter) in which the flexibility gradually increases (i.e., the stiffness decreases) distally. In this regard, the proximal end of the first region has a lower flexibility than the distal end of the first region. A second region (e.g., the length of the catheter) can be located distal to the first region and have a uniform flexibility or a gradually decreasing flexibility. In either case of the second region, at least a portion of the second region will have a lower flexibility than the lowest flexibility of the first region. For example, if the second region has a uniform flexibility, its flexibility may be lower than one or all of the distal, middle, or proximal ends of the first region. If the flexibility of the second region gradually decreases, the flexibility at one or all positions within the second region may be lower than one or all of the distal, middle, or proximal ends of the first region.

[0052] In any of the previous examples with a uniform flexible region or a gradually increasing / decreasing flexibility, the second region of increased flexibility can extend to the distal end of the catheter. Alternatively, another third region can be located distal to the second region and can extend to the distal end of the catheter. The third region can have increased, decreased, gradually increasing, gradually decreasing, or the same flexibility relative to the second region (or one or more positions in the second region). In these examples, the length of the first region can be in the range of about 0.5 to 3 cm (e.g., 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 cm, or lengths between these values). In another example, the length of the first region can exceed 3 cm (e.g., up to 15 cm), which may prove useful for peripheral or cardiac applications in addition to the neurovascular system.

[0053] The flexibility / stiffness of the catheter, particularly the distal region of the catheter, can be determined in various ways using various features, including but not limited to one or more of the following features.

[0054] In a first example, the stiffness of the outer sheath or cannula of the catheter can consist of regions of different hardness (e.g., durometer value) or flexibility. The outer sheath can have multiple discrete segments or regions composed of materials of different hardness and / or flexibility. This can be achieved by using different materials for different segments / regions and / or different thicknesses for different segments / regions. Alternatively, the outer sheath can be formed from a single continuous segment / region with varying hardness and / or flexibility (e.g., by mixing materials in different regions during the formation or extrusion of the tubular outer sheath, or by increasing or decreasing the sheath thickness in different regions). Alternatively, the variable thickness can be achieved by variable rate dip coating.

[0055] In a second example, the stiffness / flexibility of the catheter can be altered by changing the characteristics of coils located within the catheter wall (e.g., beneath an outer sheath) and extending at least through the distal region of the catheter. The spacing between individual coils can be increased to increase flexibility or decreased to reduce flexibility. Alternatively or additionally, the thickness / diameter of the wire can be increased to reduce flexibility or decreased to increase flexibility. Thus, the spacing in the coils can initially increase gradually distally and then decrease distally, and / or the diameter of the wire can initially decrease distally and then increase. Alternatively or additionally, the coils can be composed of two or more materials having different flexibilities, which can be connected to each other (e.g., by welding, etc.) such that the flexibility is varied along the length of the coil. In some embodiments, the material of the coils can be nitinol (e.g., a metal alloy of nickel and titanium). In one example, the distal region 118A of the coil layer 118 and / or one or more other regions can be of nitinol material. In this example, by applying nitinol material along the distal region of the coil wire, the stiffness of the catheter along the distal region can be greater than other regions of the catheter where the corresponding regions of the coil wire do not incorporate nitinol material. In turn, the increased stiffness of the distal region of the catheter can reduce kinking and the mechanical hysteresis of the catheter can be improved when the catheter is advanced to a target location within a patient. In some embodiments, one or more regions of the coils can be heat treated to achieve certain mechanical properties. In one example, the distal region 118A of the coil layer 118 and / or one or more other regions can be heat treated to achieve a desired hardness and / or flexibility. In this example, by heat treating the coils along the distal region of the coil, the stiffness of the catheter along the distal end can be increased (relative to other regions that are not heat treated). Thus, kinking can be reduced and the catheter can improve mechanical hysteresis.

[0056] In a third example, the stiffness / flexibility of the catheter can be altered by changing the properties of a braided wire tubular layer located within the catheter wall (e.g., between an outer sheath and an inner coil, or below the inner coil). The braided wire can increase the weft density to reduce flexibility, or decrease the weft density to increase flexibility. In one example definition, the weft density is the number of times the guide wires in the braid cross each other per inch length along the longitudinal axis. Alternatively or additionally, the wires forming the braided wire can increase in thickness to reduce flexibility, or decrease in thickness to increase flexibility. Alternatively or additionally, the braided wire tubular layer can be composed of two or more materials having different flexibilities, which can be braided together to vary the flexibility along the length of the braided wire tubular section. Alternatively or additionally, the braided wire tubular layer can utilize two or more braiding patterns having different flexibilities in order to vary the flexibility along the length of the braided wire tubular section. In some embodiments, the material of the braided wire can be nitinol (e.g., a metal alloy of nickel and titanium). In one example, the distal region of the braided wire and / or other regions of the braided wire can be of nitinol material. In some embodiments, the stiffness of the catheter can be increased by incorporating nitinol material along the distal region of the braided wire. Accordingly, kinking can be reduced, and the catheter can improve mechanical hysteresis as it is advanced to a target location within a patient's body.

[0057] In a fourth example, the stiffness / flexibility of the catheter can be altered by changing the properties of a catheter liner that can form the lumen of the catheter or the passageway between its proximal and distal ends. The liner can be formed from two or more tubular sections that include materials of different hardnesses or flexibilities. In some examples, the liner can be formed from a first tubular section of a first material (e.g., PTFE) and a second tubular section that is connected to the distal end of the first tubular section and is formed from a second material (e.g., a polyolefin elastomer) that is softer or more flexible than the first material. In another example, a third tubular section can be connected to the distal end of the second tubular section and can be composed of the first material or a different third material that is harder or less flexible than the second material. In another example, the liner can not have discrete connected tubular sections, but rather can be formed as a single tubular member that gradually changes in hardness or flexibility, such as by gradually changing the amount or combination of different materials having different hardnesses, or by varying the thickness of the liner in various regions (e.g., thinner regions are more flexible relative to thicker regions).

[0058] In a fifth example, a radiopaque marker can extend from the distal end of the catheter to form a distal tip. The radiopaque marker can be integral with or attached to the catheter body. The radiopaque marker can be composed of a material that is harder or less flexible than the hardness or flexibility of the second most distal portion of the catheter from which the radiopaque marker extends.

[0059] In a sixth example, the distal portion or distal tip may be constructed, in part, using a polymer blend or resin mixed with a radiopaque material such as barium sulfate or tantalum. The radiopaque material may be added to the polymer blend or resin before or during an extrusion step. This can impart radiopaque properties to the distal portion or distal tip, allowing the user or operator to visualize the catheter tip during use without significantly altering the material properties (e.g., stiffness, hardness) of the distal portion or tip of the catheter.

[0060] In some examples, the length of the catheter located in the distal portion of the catheter includes the regions of increased flexibility and decreased flexibility described previously. The distal portion of the catheter can generally span from about 10 cm to 40 cm (e.g., 10 cm, 11 cm, 12 cm, 13 cm, 14 cm, 15 cm, 16 cm, 17 cm, 18 cm, 19 cm, 20 cm, 21 cm, 22 cm, 23 cm, 24 cm, 25 cm, 26 cm, 27 cm, 28 cm, 29 cm, 30 cm, 31 cm, 32 cm, 33 cm, 34 cm, 35 cm, 36 cm, 37 cm, 38 cm, 39 cm, 40 cm, or lengths between these values) of the distal and proximal ends of the catheter.

[0061] Starting from the proximal end of the distal portion, the distal portion can increase in flexibility distally along its length and then decrease in flexibility. In one example, the region of decreased flexibility can be located between 0.5 cm and 5 cm from the distal end of the catheter. For example, 0.5 cm, 1 cm, 1.5 cm, 2 cm, 2.5 cm, 3 cm, 3.5 cm, 4 cm, 4.5 cm, 5 cm, or lengths between these values.

[0062] In another aspect of the present invention, the catheter stiffness can increase significantly along the proximal region relative to the distal region. For example, the distal region can be between about 0 to 12 cm from the distal end with an average stiffness of about 5 gf / mm, and the proximal region can be between 12 to at least 40 cm with an average hardness of 400 - 600 gf / mm. In some examples, the stiffness of the proximal region relative to the distal region can increase by 7000 - 11000% (e.g., 7000%, 7500%, 8000%, 8500%, 9000%, 9500%, 10000%, 10500%, 11000%, and percentage values within or near these percentages). These stiffness values may or may not include the increase in catheter distal stiffness discussed previously (i.e., the stiffness at the distal end may be decreased or remain the same).

[0063] Similarly, while these structural features can be applied to catheters of any type, size, and / or use (e.g., 5 French or 6 French catheters), they may be particularly beneficial for catheters having a lumen diameter of 0.088 inches and a working length (i.e., excluding the catheter hub) between about 100 cm and 135 cm (e.g., 115 cm or 125 cm). As previously mentioned, catheters with relatively small diameters (e.g., 5 or 6 French) can generally remain relatively flexible throughout their length without kinking or folding their lumens due to their relatively small diameter dimensions. However, larger diameter catheters, such as 0.088-inch lumen catheters, typically require greater reinforcement to prevent kinking and / or lumen collapse. This can result in the catheter being relatively stiff overall, which may be undesirable when entering delicate and tortuous blood vessels, such as blood vessels in the brain (e.g., the MCA). In this regard, the structural examples of the present specification may help create a catheter having a relatively rigid proximal region (e.g., an average flexibility between about 400 and 600 gf / mm) and a relatively flexible distal region (e.g., an average flexibility between about 350 and 3 gf / mm). For example, such flexibility can be achieved by including one or more of the liners, coil layers, braided layers, and outer sheath layers discussed in the present specification, including the values of the various aspects of each layer, including materials, hardness, coil pitch, wire diameter, weft density, cross-sectional length, and other features further discussed in the present specification.

[0064] Figure 1-7 Aspects of an exemplary catheter 100 having structural features that provide the desired flexibility and pushability while reducing kinking are shown. An example of such flexibility can be seen in Figure 8 and Figure 9 which compare a catheter 100 having a 0.088-inch lumen diameter (designated as Catheter B) to a standard 6 French lumen catheter (designated as Catheter A). Figure 10-12 More examples of flexibility can be seen in

[0065] Figure 10 show that the total length of the catheter may vary (e.g., between 100 cm and 200 cm, although in some examples the total length may be less than 100 cm or greater than 200 cm), and the stiffness or flexibility of the proximal portion (e.g., between about 30 cm and 40 cm from the distal end to the proximal end) may be substantially uniform.

[0066] Figure 11Shows a non-limiting example range of stiffness values along a portion of the catheter length, where the stiffness has an increasing trend. This portion is shown as being approximately 15 cm to 30 cm from the distal tip, but it should be understood that the positioning of the increasing portion may vary in different examples and should not be construed as being limited to the exact values shown in the figure. Additionally, the effective length of the decreasing portion may also vary and should not be understood as being limited to the example shown. For example, the increasing portion can be located between approximately 10 cm and 40 cm from the distal tip, between approximately 5 cm and 35 cm from the distal tip, between approximately 15 cm and 30 cm from the distal tip, and so on.

[0067] Figure 12 Shows a non-limiting example range of stiffness values along the penultimate distal portion of the catheter length, where the stiffness may initially be uniform and then begin to increase. This portion is shown as being approximately 5 cm to 15 cm from the distal tip, but it should be understood that the positioning of the penultimate distal portion may vary in different examples and should not be construed as being limited to the exact values shown in the figure. For example, depending on the length of the stiffer distal portion, the penultimate distal portion can be considered to start at 0.5 cm, 1.0 cm, 1.5 cm, 2.0 cm, 2.5 cm, 3.0 cm, 3.5 cm, 4.0 cm, 4.5 cm, or 5.0 cm from the distal tip. In some examples, such as examples where the length of the stiffer distal portion may be greater than 5 cm, the penultimate distal portion can be considered to start at a position greater than 5 cm from the distal tip.

[0068] Figure 11-12 Both show stiffness ranges measured in gf / mm. More specifically, Figure 11-12 Shows that the corresponding stiffness along the catheter length may vary, including portions labeled "upper tolerance", "target tolerance", and "lower tolerance". Therefore, it should be understood that the actual values of the stiffness of the various segments along the catheter length may vary and, in some examples, may even exceed the shown ranges, which are for illustrative purposes only.

[0069] Note that the preceding data points are merely examples or estimates of values according to some configurations of this specification and are not necessarily the values for all examples / embodiments.

[0070] As shown, the standard 6 French lumen catheter A generally remains flexible along most of its length, with an average stiffness of approximately 180 to 190 gf / mm in the proximal portion, and the flexibility increasing distally to an average stiffness of 6 to 2 gf / mm. Due to the relatively small lumen diameter, although highly flexible, it may tend to resist collapse.

[0071] Example The 0.088-inch lumen diameter catheter B generally maintains relatively low flexibility over most of its length, with an average stiffness of about 400 to 600 gf / mm or about 500 gf / mm in the proximal portion, and the flexibility at its distal end increases to an average stiffness of about 350 to 2 gf / mm or 5 to 2 gf / min. This stiffness distribution can be achieved by the structural elements discussed further below, and can also resist kinking and collapse of the catheter lumen.

[0072] As Figure 1 shown, the catheter 100 can generally include a working length, which includes a distal portion or length 100A and a proximal portion or length 100B. The proximal end of the proximal portion 100B can be connected to the catheter hub 106 and the stress relief sheath 106A (also see Figure 6 ), and the distal end of the distal portion 100A can optionally include a radiopaque marker 108 located outside or within the wall of the catheter 100. The catheter 100 can include a lumen that opens proximally at the catheter hub 106, and the lumen extends through the proximal portion 100B, the distal portion 100A, and opens at the distal end of the catheter 100.

[0073] The catheter can include at least several different layers that make up its catheter wall. Specifically, the inner liner 110 ( Figure 2 ) can form the inner surface of the catheter lumen, the coil layer 116 can be disposed on the inner liner 110, the braided layer 120 can be disposed on the coil layer 116, and the outer sheath 102 can be disposed on the braided layer 120. Alternatively, the positions of the coil layer 116 and the braided layer 120 can be interchanged or reversed. Alternatively, in some examples, one of the coil layer 116 or the braided layer 120 can be omitted.

[0074] Returning to Figure 2 , in one example, the inner liner 110 can include a proximal tubular portion 112 and a distal tubular portion 114, which can be connected together or extruded / molded into a single tube. In the case of using two separate tubes, the distal end of the proximal tubular portion 112 and the proximal end of the distal tubular portion 114 can be connected together in various ways, such as by an adhesive, heating / melting, and / or connection to other components. In Figure 2 the example, a connecting layer 116 in the form of a third tube can be placed at both ends. The connecting layer 116 can be a single integral tube, or can be composed of a first tube member 116A and a second tube member 116B, both of which are cut with an angular bias relative to each other such that their cut surfaces can fit together and be connected by an adhesive. The adhesive can be further applied between the two members 116A, 116B and the portions 114, 112 respectively.

[0075] The proximal tubular portion 112 may be made of a material that is relatively stiffer than the distal tubular portion 114. For example, the proximal tubular portion 112 may be made of PTFE, and the distal tubular portion 114 may be made of a softer polyolefin elastomer. The connecting layer may also be made of a relatively soft material, such as LLDPE (linear low density polyethylene) or LDPE (low density polyethylene).

[0076] The connecting layer 116 and the interface between the two portions 112, 114 may be located within a range of 8 to 20 cm from the distal end of the catheter 100. For example, 8 cm, 9 cm, 10 cm, 11 cm, 12 cm, 13 cm, 14 cm, 15 cm, 16 cm, 17 cm, 18 cm, 19 cm, 20 cm, or a position between these values. Figure 5 An example position of the connecting layer 116 relative to a portion of the outer sheath 102 in the distal portion 100A is shown.

[0077] The coil layer 118 as Figure 3 shown may be located above the inner liner 110, as shown by the position of the connecting layer 116. The coil layer 118 may extend to the most distal end of the catheter 100, or may terminate a short distance before the distal end of the catheter 100 (e.g., 0.5 cm, 1.0 cm, 1.5 cm, or 2.0 cm from the distal end). The coil layer 118 may be composed of coils with pitch variations in different regions or lengths. Generally, the flexibility of the coil layer 118 increases distally. However, the flexibility of the coil layer 18 near its distal end may optionally be reduced.

[0078] In one example, the coil layer 118 may have a distal region 118A, an intermediate region 118B, and a proximal region 118C. The length 118D of the distal region 118A may be in the range of 1.5 cm to 3 cm (e.g., 1.5 cm, 1.6 cm, 1.7 cm, 1.8 cm, 1.9 cm, 2.0 cm, 2.1 cm, 2.2 cm, 2.3 cm, 2.4 cm, 2.5 cm, 2.6 cm, 2.7 cm, 2.8 cm, 2.9 cm, 3.0 cm, or a length between these values).

[0079] The length 118E of the intermediate region 118B may be in the range of 7 cm to 10 cm (e.g., 7.0 cm, 7.1 cm, 7.2 cm, 7.3 cm, 7.4 cm, 7.5 cm, 7.6 cm, 7.7 cm, 7.8 cm, 7.9 cm, 8 cm, 8.1 cm, 8.2 cm, 8.3 cm, 8.4 cm, 8.5 cm, 8.6 cm, 8.7 cm, 8.8 cm, 8.9 cm, 9.0 cm, or a length between these values).

[0080] The length 118F of the distal region 118C can be in the range of 95 to 120 cm (e.g., 95 cm, 96 cm, 97 cm, 98 cm, 99 cm, 100 cm, 101 cm, 102 cm, 103 cm, 104 cm, 105 cm, 106 cm, 107 cm, 108 cm, 109 cm, 110 cm, 111 cm, 112 cm, 113 cm, 114 cm, 115 cm, 116 cm, 117 cm, 118 cm, 119 cm, 120 cm, or lengths between these values).

[0081] The flexibility of the coil layer 118 can be controlled by the spacing of the individual coils of the layer (e.g., a larger spacing increases flexibility), by changing the diameter of the wire (e.g., a smaller diameter increases flexibility), and / or by using a material of a certain softness. In one example, the coil layer 118 is formed of relatively soft nitinol wire or stainless steel wire that is relatively harder than nitinol wire.

[0082] In one example, the intermediate region 118B has greater flexibility than the proximal region 118C, and the distal region 118A has greater flexibility than the intermediate region 118B. In such examples, the turns of the proximal region 118C can be spaced from each other in an inclusive range of about 0.003 inches to 0.0055 inches (e.g., 0.003 inches, 0.0035 inches, 0.004 inches, 0.0045 inches, 0.005 inches, 0.0055 inches, or lengths between these values). The turns of the intermediate region 118B can be spaced apart in the range of about 0.005 inches to 0.007 inches (e.g., 0.005 inches, 0.0055 inches, 0.006 inches, 0.0065 inches, 0.007 inches, 0.0075 inches, 0.008 inches, or lengths between these values). The turns of the distal region 118A can be spaced apart in the range of about 0.006 inches to 0.010 inches (e.g., 0.006 inches, 0.0065 inches, 0.007 inches, 0.0075 inches, 0.008 inches, 0.009 inches, 0.0095 inches, 0.010 inches, or lengths between these values).

[0083] In another example, the intermediate region 118B has greater flexibility than the proximal region 118C, and the distal region 118A has greater flexibility than the intermediate region 118B. In such examples, the turns of the proximal region 118C can be spaced from each other within an inclusive range of from about 0.003 inches to 0.0055 inches (e.g., 0.003 inches, 0.0035 inches, 0.004 inches, 0.0045 inches, 0.005 inches, 0.0055 inches, or lengths between these values). The turns of the intermediate region 118B can be spaced apart within a range of from about 0.005 inches to 0.007 inches (e.g., 0.005 inches, 0.0055 inches, 0.006 inches, 0.0065 inches, 0.007 inches, 0.0075 inches, 0.008 inches, or lengths between these values). The turns of the distal region 118A can be spaced from each other within a range of from about 0.003 inches to 0.0055 inches (e.g., 0.003 inches, 0.0035 inches, 0.004 inches, 0.0045 inches, 0.005 inches, 0.0055 inches, or lengths between these values).

[0084] The braided layer 120 can be seen best Figure 4 in and can be located above or below the coil layer 110. The braided layer 120 can extend to the distalmost end of the catheter 100 or can terminate a short distance before the distal end of the catheter 100 (e.g., 0.5 cm, 1.0 cm, 1.5 cm, or 2.0 cm from the distal end), or can extend to the start of the catheter sleeve 106 ( Figure 6 ). The braided layer 120 can be composed of one or more wires braided together. Generally, the braided layer 120 increases in flexibility distally, however, the braided layer 118 can also selectively decrease in flexibility near its distal end.

[0085] In one example, the braided layer 120 may have a distal region 120A, a middle region 120B, and a proximal region 120C. The length of the distal region 120A may be in the range of 9 cm to 12 cm (e.g., 9 cm, 9.5 cm, 10 cm, 10.5 cm, 11 cm, 11.5 cm, 12 cm, or lengths between these values). The length of the middle region 120B may be in the inclusive range of 1.5 cm and 3 cm (e.g., 1.5 cm, 1.6 cm, 1.7 cm, 1.8 cm, 1.9 cm, 2.0 cm, 2.1 cm, 2.2 cm, 2.3 cm, 2.4 cm, 2.5 cm, 2.6 cm, 2.7 cm, 2.8 cm, 2.9 cm, 3.0 cm, or lengths between these values). Optionally, the lengths of the distal region 120A and the middle region 120B may be substantially the same as the lengths of the distal region 118A and the middle region 118B of the coil layer 118 (e.g., the combined length is about 10.5 cm).

[0086] The length of the distal region 120C may be in the range of 95 to 120 cm (e.g., 95 cm, 96 cm, 97 cm, 98 cm, 99 cm, 100 cm, 101 cm, 102 cm, 103 cm, 104 cm, 105 cm, 106 cm, 107 cm, 108 cm, 109 cm, 110 cm, 111 cm, 112 cm, 113 cm, 114 cm, 115 cm, 116 cm, 117 cm, 118 cm, 119 cm, 120 cm, or lengths between these values).

[0087] The flexibility of the braided layer 120 can be controlled by the density of the braid or the weft density of the braid (higher weft density reduces flexibility), by changing the diameter of the wire (e.g., smaller diameter increases flexibility), and / or by using a material with a certain softness. In one example, the braided layer 120 is formed of one or more relatively soft braided nitinol wires or one or more stainless steel wires that are relatively harder than nitinol wires. In one example, a region of harder braided stainless steel wire may be fixed to a region of softer nitinol wire.

[0088] In one example, the intermediate region 120B has greater flexibility than the proximal region 120C, and the distal region 120A has greater flexibility than the intermediate region 120B. In such examples, the weft density of the proximal region 120C can be in the inclusive range of 120 PPI to 140 PPI (e.g., 120 PPI, 121 PPI, 122 PPI, 123 PPI, 124 PPI, 125 PPI, 126 PPI, 127 PPI, 128 PPI, 129 PPI, 130 PPI, 131 PPI, 132 PPI, 133 PPI, 134 PPI, 135 PPI, 136 PPI, 137 PPI, 138 PPI, 139 PPI, 140 PPI, or lengths between these values).

[0089] The weft density of the distal region 120A can have an inclusive range of about 65 PPI to 90 PPI (e.g., 65 PPI, 66 PPI, 67 PPI, 68 PPI, 69 PPI, 70 PPI, 71 PPI, 72 PPI, 73 PPI, 74 PPI, 75 PPI, 76 PPI, 77 PPI, 78 PPI, 79 PPI, 80 PPI, 81 PPI, 82 PPI, 83 PPI, 84 PPI, 85 PPI, 86 PPI, 87 PPI, 88 PPI, 89 PPI, 90 PPI, or lengths between these values).

[0090] The weft density of the intermediate region 120B can transition between the weft density of the proximal region 120C and the weft density of the distal region 120A.

[0091] In another example, the intermediate region 120B has greater flexibility than the proximal region 120C, and the distal region 120A has greater flexibility than the intermediate region 120B. In such examples, the weft density of the proximal region 120C and the distal region 120A can be in the inclusive range of 120 PPI to 140 PPI (e.g., 120 PPI, 121 PPI, 122 PPI, 123 PPI, 124 PPI, 125 PPI, 126 PPI, 127 PPI, 128 PPI, 129 PPI, 130 PPI, 131 PPI, 132 PPI, 133 PPI, 134 PPI, 135 PPI, 136 PPI, 137 PPI, 138 PPI, 139 PPI, 140 PPI, or lengths between these values). The weft density of the intermediate region 120B can have an inclusive range of approximately 65 PPI to 90 PPI (e.g., 65 PPI, 66 PPI, 67 PPI, 68 PPI, 69 PPI, 70 PPI, 71 PPI, 72 PPI, 73 PPI, 74 PPI, 75 PPI, 76 PPI, 77 PPI, 78 PPI, 79 PPI, 80 PPI, 81 PPI, 82 PPI, 83 PPI, 84 PPI, 85 PPI, 86 PPI, 87 PPI, 88 PPI, 89 PPI, 90 PPI, or lengths between these values).

[0092] The outer sheath 102 is as Figure 1 and Figure 7 shown, a portion of the outer sheath 102 within the distal portion 100A of the catheter 100 is as Figure 5 shown. The outer sheath 102 can extend to the most distal end of the catheter 100 and extend proximally of the catheter 100 to the catheter hub 106. In one example, the length of the outer sheath 102 can be in the range of approximately 110 cm to 135 cm (e.g., the working length is about 115 or 125). Generally, the flexibility or hardness (e.g., hardness value) of the outer sheath 102 increases in flexibility or decreases in hardness toward the distal end of the catheter 100. However, the outer sheath 101 can also selectively decrease in flexibility or increase in hardness near the distal end of the catheter 100 (e.g., within a length of 0.5 to 3 cm from the distal end).

[0093] The outer sheath 102 is further described in terms of discrete sheath segments. However, this discussion is to be understood as including both tubular segments of different characteristics that are joined to each other to form a tubular layer and an integral tubular structure molded or extruded as a single tube having a gradually varying material and / or thickness along its length. In this regard, the properties of the tubular segments (such as hardness) may change abruptly or the properties may vary gradually along the length of the outer sheath. In an example of discrete joined segments, the segments may have an axially perpendicular cut (e.g., between segments 102A and 102B), or may have an angled cut offset with respect to the catheter axis (e.g., 45 degrees), which helps to achieve a smoother transition between materials of different hardnesses. In an example of an offset cut segment, the length measurement can be between the head ends of each end of the segment, only between portions without an offset cut, or from one offset cut head end to a position just before the opposite offset cut head end (as Figure 5 shown). These segments are also described in terms of hardness and hardness values. However, increasing and decreasing portions of different hardness values are also to be understood as having a similar increase or decrease in flexibility. All hardness values in this specification are Shore A values.

[0094] The proximal segment 102M of the outer sheath 102 can generally have the least flexibility of the outer sheath 102 to provide maximum support and stiffness. In one example, the proximal segment 102M can be composed of a relatively hard material such as Pebax and nylon (Grilamid L25). The wall thickness of the proximal segment 102M can be in the range of 0.004 to 0.007 inches (e.g., 0.004, 0.005, 0.006, 0.007, and thicknesses between these values). The length of the proximal segment 102M can be in the inclusive range of about 80 cm to about 100 cm (e.g., 80 cm, 81 cm, 82 cm, 83 cm, 84 cm, 85 cm, 86 cm, 87 cm, 88 cm, 89 cm, 90 cm, 91 cm, 92 cm, 93 cm, 94 cm, 95 cm, 96 cm, 97 cm, 98 cm, 99 cm, 100 cm, and lengths between these values). The hardness can be in the hardness value range of 50A to 120A.

[0095] The distal segments 102A - 102L can have different flexibilities relative to proximal and distal adjacent segments. In one example, this can be achieved by using different materials for each segment and / or different thicknesses for each segment. For example, the distal segments 102A - 102L can be composed of thermoplastic polyurethane elastomer (TPU) having different hardnesses or hardness values. In one example, the distal segments 102A - 102L have the same thickness in the range of 0.002 to 0.010 inches and have different hardnesses relative to proximal or distal adjacent segments to achieve varying flexibility.

[0096] In one example, each of the distal segments 102 generally has increased flexibility and / or decreased stiffness relative to the immediately adjacent proximal segment. In another example, each of the distal segments 102 generally has increased flexibility and / or decreased stiffness relative to the immediately adjacent proximal segment, except for one or more of the most distal segments of the outer sheath 102.

[0097] In one example, only the distal segment 102A has decreased flexibility or increased stiffness relative to the distal segment 102B. The length of the distal segment 102A can be in the range of 0.5 cm to 3.0 cm (e.g., 0.5 cm, 1.0 cm, 1.5 cm, 2.0 cm, 2.5 cm, 3.0 cm, or lengths between these values). The distal segment 102A can be composed of TPU or a similar material having a hardness in the range of about 20A to 100A (e.g., 20A, 21A, 22A, 23A, 24A, 25A, 26A, 27A, 28A, 29A, 30A, 31A, 32A, 33A, 34A, 35A, 36A, 37A, 38A, 39A, 40A, 41A, 42A, 43A, 44A, 45A, 46A, 47A, 48A, 49A, 50A, 51A, 52A, 53A, 54A, 55A, 56A, 57A, 58A, 59A, 60A, 61A, 62A, 63A, 64A, 65A, 66A, 67A, 68A, 69A, 70A, 71A, 72A, 73A, 74A, 75A, 76A, 77A, 78A, 79A, 80A, 81A, 82A, 83A, 84A, 85A, 86A, 87A, 88A, 89A, 90A, 91A, 92A, 93A, 94A, 95A, 96A, 97A, 98A, 99A, 100A, and hardness values between these values). The distal segment 102B can be composed of TPU or a similar material having a hardness that is at least one value lower than that of the distal segment 102A, but 20 to 30 units lower. For example, the distal segment 102A can be 27A - 32A (e.g., 27A, 28A, 29A, 30A, 31A, or 32A), and the distal segment 102B can be 10A - 14A (e.g., 10A, 11A, 12A, 13A, or 14A).

[0098] In one example, relative to distal segment 102B, only the flexibility of distal segments 102A and 102B is reduced or the hardness is increased. The lengths of distal segments 102A and 102B can be in the range of 0.5 cm to 3.0 cm (e.g., 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 cm, or lengths between these values). Distal segment 102C can be composed of TPU or a similar material, and its hardness is at least one unit lower than that of distal segment 102B, but 20 to 30 units lower. Distal segment 102A can be the same as distal segment 102B or at least one unit lower. For example, the hardness of distal segment 102A can be in the inclusive range of 27A - 32A (e.g., 27A, 28A, 29A, 30A, 31A, 32A, or hardness values between these values), the hardness of distal segment 102B can be the same as or lower than that of segment 102A in the same inclusive range, and the hardness of distal segment 102C can be in the inclusive range of about 10A - 14A (e.g., 10A, 11A, 12A, 13A, 14A, or durometers between these two values). This pattern can be further extended such that any number of several distal segments 102A, 102B, 102, 102D, and / or 102E can gradually increase in hardness and decrease in flexibility in the proximal direction with hardness values in the inclusive range of 27A - 32A (e.g., 27A, 28A, 29A, 30A, 31A, 32A, or hardness values between these values), as long as the hardness of each part is the same as or higher than that of the proximally adjacent part.

[0099] Distal segment 102A is described as a segment of outer sheath 102. However, the distal segment can alternatively be part of a different layer and extend beyond segment 102B of outer sheath 102. For example, distal segment 102A can be attached to inner liner 110 or can be part of inner liner 110 (e.g., part 114).

[0100] Note that the hardness of parts 102L to 102F generally also gradually decreases (flexibility increases) in the distal direction, although specific Shore value examples are not necessarily provided in this specification. For example, these Shore values can be in the inclusive range of about 20D to 100D.

[0101] Table 1 below provides several examples of hardness value series. While the increase in hardness of the distal part (e.g., 102A) is one aspect of outer sheath 102, another aspect is the process of increasing hardness in the proximal part, as shown in the figure below, which may significantly increase the proximal stiffness. The sharp increase in proximal stiffness may be particularly helpful for relatively large catheters defined elsewhere in this specification to provide pushability without kinking or folding while allowing navigation of curved blood vessels and their distal parts.

[0102] Table 1

[0103] Another way to describe the outer sheath 102 within the distal portion 100A of the catheter 100 is that at a certain length from the distal end of the catheter 100, the outer sheath 102 can have a certain hardness / hardness value or an average hardness / hardness value. Table 2 below provides example lengths and hardnesses. The following lengths can be referred to as the most distal (0 - 0.5 cm or 0 - 0.05 cm), the second distal (0.5 - 3.5 cm or 0.05 - 3.5 cm), and so on for the remaining segments. Using a relatively short most distal portion (e.g., a length of 0 - 0.5 cm) may assist in guiding the aortic arch.

[0104] Table 2

[0105] Table 2B

[0106] Table 2C

[0107] In the examples shown in Table 2B and Table 2C above, the length of the most distal portion with a hardness of 30A Shore hardness value is 0 - 0.05 cm. Alternatively, the length range of the portion can be from 0 - 0.01 cm to 0 - 0.1 cm (or up to 0.5 cm as shown in Table 2). This is for the operator in the aortic arch (such as Figure 14Navigation, particularly in the case of a type III aortic arch as shown, may be advantageous or beneficial. Type III aortic arches are relatively uncommon in the general population. Estimates vary, but may be less than 25% of the adult population. However, type III aortic arches are more common in elderly patients and in patients with risk factors for stroke, aneurysms, and other diseases or acute medical problems that may require endovascular intervention. Again, estimates vary, but the prevalence of type III aortic arches in patients undergoing neuroendovascular surgery may be as high as 50% or more. Due to the double hairpin turns between the descending aorta, aortic arch, and the access to the brachiocephalic arteries (right common carotid artery (RCA) or left common carotid artery (LCA)), type III aortic arches are particularly difficult to navigate during endovascular procedures. A catheter such as described herein, particularly a catheter having a relatively high stiffness in its most distal portion (e.g., as described in Tables 2, 2B, 2C), may be advantageous to the operator and / or patient by providing a distal tip that is sufficiently stiff such that it does not collapse or "accordion-fold" when contacting the vessel wall during navigation through tortuous anatomy (e.g., in a type III aortic arch). However, the distal catheter portion immediately adjacent to the distal tip (i.e., the penultimate portion) may be sufficiently flexible to provide sufficient flexibility near the distal end of the catheter. This can provide improved seaworthiness and trackability in challenging and / or tortuous anatomy, such as at least type II or type III aortic arches.

[0108] Another way to describe the outer sheath 102 within the distal portion 100A of the catheter 100 is that the stiffness or hardness value of the outer sheath 102 can approximately double, triple, or the like from the proximal portion to the distally adjacent distal portion (e.g., from distal portion 102B to distal portion 102A). For example, the hardness value between distal portions 102B to 102A can increase by approximately 100 (i.e., double), 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300 (i.e., triple), 310, 320, 330, 340, 350% or a percentage between these values. In this case

[0109] Another way to describe the distal portion 100A of the catheter 100 as a whole is that the stiffness can approximately double, triple, or the like from the proximal point to the distal point of the distal portion 100A. For example, the stiffness at points within 0 to 2 cm from the distal end may be approximately double, triple, or the like compared to points within 2 cm to 4 cm. For example, the stiffness between two points may increase by about 100% (i.e., double), 110%, 120%, 130%, 140%, 150%, 160%, 170%, 180%, 190%, 200%, 210%, 220%, 230%, 240%, 250%, 260%, 270%, 280%, 290%, 300% (i.e., triple), 310%, 320%, 330%, 340%, 350%, or a percentage between these values.

[0110] Another way to describe the overall flexibility of the catheter may include flexibility values at different positions of the distal end of the catheter 100. Example values are shown in Tables 3 and 4 below. These can be example values, including ranges 10% above or below each of these values, or can be considered as the average of length ranges overlapping with the specified length values (e.g., equal-length overlap at the proximal and distal ends).

[0111] Table 3

[0112] Table 4

[0113] The following examples relate to example combinations of the foregoing catheter layers. Although specific numbers (such as length, PPI, coil width, hardness value, etc.) may not be specified below, refer to the example numbers for each layer discussed previously. The stiffness at the 0.5 cm distal position can be within the inclusive range between 4 gf / mm and 20 gf / mm. The hardness at the 2 cm distal position can be within the inclusive range from 2 gf / mm to 18 gf / mm.

[0114] In one example, the catheter 100 includes a coil layer 118, a braided layer 120, and an outer sheath layer 102. The flexibility of the coil layer 118 increases until its distal end, the flexibility of the braided layer 120 increases to its distal end, and the flexibility of the outer sheath layer increases towards its distal end but then decreases until its distal end (e.g., decreases within the length between 0.5 to 3 cm from its distal end).

[0115] In one example, the catheter 100 includes a coil layer 118, a braided layer 120, and an outer sheath layer 102. The flexibility of the coil layer 118 increases until its distal end, but then decreases until its distal end (e.g., decreases between 0.5 and 3 cm in length starting from its distal end). The flexibility of the braided layer 120 increases to its distal end, and the flexibility of the outer sheath layer 104 increases towards its distal end.

[0116] In one example, the catheter 100 includes a coil layer 118, a braided layer 120, and an outer sheath layer 102. The flexibility of the coil layer 118 increases until its distal end, the flexibility of the braided layer 120 increases to its distal end, but then decreases until its distal end (e.g., decreases between 0.5 and 3 cm in length starting from its distal end), and the flexibility of the outer sheath layer 104 increases towards its distal end.

[0117] In one example, the catheter 100 includes a coil layer 118, a braided layer 120, and an outer sheath layer 102. The flexibility of the coil layer 118 increases until its distal end, but then decreases until its distal end (e.g., decreases between 0.5 and 3 cm in length starting from its distal end), the flexibility of the braided layer 120 increases to its distal end, but then decreases to its distal end (e.g., decreases between 0.5 and 3 cm from its distal end).

[0118] In another example, regardless of the stiffness of the distal tip of the catheter 100, the proximal portion of the catheter 100 can have a catheter flexibility range that has a relatively high proximal stiffness and a relatively low distal stiffness (e.g., as Figure 8 and Figure 9 shown, between 2 - 40 cm from the distal tip of the catheter). The combination of high proximal stiffness and low distal stiffness can be particularly effective for the navigation of relatively large catheters and for resisting kinking and collapse.

[0119] For example, between the distal tip and a position approximately 7 - 12 cm proximal, the average stiffness of the catheter 100 is approximately 5 gf / mm. Between a position approximately 4 - 12 cm proximal and a position approximately 40 - 100 cm from the distal tip, the average stiffness is approximately 450 - 550 gf / mm. In other words, the average stiffness between 7 - 12 cm proximal to the distal tip and approximately 40 - 100 mm from the distal tip is approximately 7000 - 11000% higher than between the distal tip and a position approximately 7 - 12 cm proximal, more specifically, 9000 - 10000% higher (e.g., 7000%, 7500%, 8000%, 8500%, 9000%, 10000%, 10500%, 11000%, and percentage values within or near these percentages).

[0120] Described in another way, between the distal end of the catheter and about 10 cm proximal to the distal end, the average stiffness is between about 2 - 10 gf / mm. Between about 10 cm to 13 cm from the distal end, the average proximal stiffness increases from about 9 gf / mm to 39 gf / mm. Between about 13 cm to 30 cm from the distal end, the average proximal stiffness increases from about 29 gf / mm to 480. Between about 30 cm to 40 cm from the distal end, the average proximal stiffness decreases from about 480 gf / mm to 495 gf / mm. These exemplary values and the other specific exemplary values in Table 5 can vary by about 10%.

[0121] Table 5

[0122] As Figure 8-13 shown, an exemplary catheter may include a stiffness profile that varies along its length. The catheter may include at least a distal portion, a penultimate distal portion, an antepenultimate proximal portion, and a proximal portion. The stiffness of the distal portion may be greater than the stiffness of the penultimate distal portion. The stiffness of the antepenultimate proximal portion may be greater than the stiffness of the penultimate distal portion, and the stiffness gradually increases along the length of the antepenultimate proximal portion. The stiffness of the proximal portion may be substantially uniform.

[0123] For example, the stiffness of the most distal portion of the catheter may be greater than the stiffness of the penultimate distal portion of the catheter adjacent to the proximal end of the most distal portion. Before transitioning to the antepenultimate proximal portion with an increasing stiffness, the penultimate distal portion may include a substantially uniform lower stiffness. The proximal portion of the catheter may include a substantially uniform stiffness.

[0124] For example, a catheter can include an elongate catheter body and an outer sheath having a distal region positioned along the elongate catheter body. The distal region can have a variable hardness, which decreases in the distal direction along the longitudinal axis towards the distal end of the catheter body and then increases until the most distal end of the catheter body. The hardness of the outer sheath at the most distal end of the catheter body can be between 20A and 50A Shore hardness. The hardness of the outer sheath in a portion near the most distal end of the catheter body can be between 10A and 20A Shore hardness. The distal region having a variable hardness with decreasing hardness towards the distal end of the catheter body can include a first outer sheath segment and a second outer sheath segment, where the first outer sheath portion has a first hardness and the second outer sheath portion has a second hardness. The interface region can have a smooth transition from the first hardness to the second hardness. The length of the interface region can be at least 0.5 cm or between 0.1 cm and 1.0 cm. The interface region can include a bond (e.g., butt bonding or scarf bonding) between two adjacent regions having different hardnesses or stiffnesses. The bonding can be a diagonal joint (e.g., scarf joint), a linear joint (e.g., butt joint), or various other types of bonding. The advantages of a butt joint or a scarf joint may include, at least, that the transition between the respective stiffnesses or hardnesses of each adjacent joint region may be smoother than other types of joints (e.g., butt joints), which have a sharper transition zone between the respective regions.

[0125] For example, a catheter can include an elongate catheter body having a distal portion, a proximal portion, and an intermediate portion therebetween. The distal portion can have a first stiffness of less than 50 gf / mm, the intermediate portion can have a second stiffness, and the proximal portion can have a third stiffness of greater than 400 gf / mm. The intermediate portion can extend from 7 - 13 cm from the distal tip of the elongate catheter body to 25 - 35 cm from the distal tip of the elongate catheter body. The variable range of the second stiffness of the intermediate portion can increase at a substantially linear rate in the distal-to-proximal direction. The entire variable range of the second stiffness of the intermediate portion can increase at a rate of no more than 60 gf / mm per centimeter of catheter body length in the distal-to-proximal direction (e.g., at a rate of 10 - 60 gf / mm per centimeter).

[0126] For example, a catheter can include an elongate catheter body including a proximal portion, an intermediate portion, and a distal portion. The intermediate portion can be between the proximal portion and the distal portion. The intermediate portion can increase between a first stiffness and a second stiffness. The first stiffness can be located at the distal end of the intermediate portion and the second stiffness can be at the proximal end of the intermediate portion.

[0127] In different examples, the positions of the proximal and distal ends of the inner portion may vary. The distal end of the middle portion may be located between about 0.01 cm and 15 cm from the distal tip of the distal portion. The distal end of the middle portion may be located between about 5 cm and 10 cm from the distal tip of the distal portion. The proximal end of the inner portion may be located between about 20 cm and 40 cm from the distal tip of the distal portion. The proximal end of the middle portion may be located between about 25 cm and 35 cm from the distal tip of the distal portion. The distal end of the inner portion may be located at about 10 cm from the distal tip of the distal portion. The proximal end of the inner portion may be located at about 30 cm from the distal tip of the distal portion.

[0128] In different examples, the values of the corresponding first and second stiffnesses may vary. The first stiffness may be less than 50 gf / mm. The second stiffness may be greater than 400 gf / mm, and the first stiffness may be between about 1 gf / mm and 100 gf / mm. The increase between the first and second stiffnesses may be substantially linear or non-linear. The first stiffness may be between about 2 gf / mm and 10 gf / mm. The second stiffness may be about 500 gf / mm.

[0129] Figure 8 and Figure 10 shows an example of the stiffness distribution along the length of the catheter. As shown, the distal portion including the distal tip may have a first stiffness, and the second stiffness of the penultimate distal portion may be less than the first stiffness of the distal portion. Although Figure 8 and Figure 10 specific stiffness values are shown in gf / mm for illustrative purposes, it should be understood that the listed values are not meant to limit the scope. Additionally, in different examples, the corresponding lengths of the distal and penultimate distal portions may vary.

[0130] Continuing to refer to Figure 8 and Figure 10 , it can be seen that the penultimate proximal portion may be adjacent to the penultimate distal portion in the proximal direction. The penultimate proximal portion may include a gradually increasing stiffness that increases along the length of the penultimate proximal portion. The increase in stiffness may be linear or non-linear, and the length segments of the penultimate proximal portion may include a substantially uniform stiffness. The penultimate proximal portion may transition to the proximal portion, along which the stiffness may be substantially uniform up to and including the proximal end of the catheter.

[0131] Referring to Figure 8 and Figure 10, it can be seen that the approximate length of the distal portion may be between about 0.5 cm and 5.0 cm, but longer or shorter lengths may also be used. For example, the approximate length of the distal portion may be between 0.01 cm and 5 cm, or in other examples, between 0.01 cm and 0.2 cm.

[0132] The length of the penultimate distal portion is about 5 cm to 10 cm, but longer or shorter lengths may also be used. The length of the penultimate proximal portion is about 15 cm to 40 cm, but longer or shorter lengths may also be used. The length of the proximal portion may be between about 70 cm and 130 cm, but longer or shorter lengths may also be used. The total length of the catheter, including the distal, penultimate distal, penultimate proximal, and proximal portions, may have a length of about 100 cm to 200 cm, but longer or shorter lengths may also be used.

[0133] Figure 11-13 illustrates that the stiffness of each part of the catheter should not be construed as limited to Figure 8-10 the specific example values shown in, and illustrates example ranges of such stiffness. However, it should also be understood that in some examples, the stiffness of one or more parts may exceed Figure 11-13 the example ranges shown.

[0134] Figure 11 shows the stiffness range of the penultimate proximal portion of the catheter, along which the stiffness may increase. Figure 12 shows the stiffness range along the penultimate distal portion, indicating that at least a portion of the penultimate distal portion may include substantially uniform stiffness. Figure 13 shows the stiffness ranges of the proximal segment of the penultimate proximal portion and the distal segment of the proximal portion, illustrating how the stiffness increasing segment transitions to the stiffness uniform segment.

[0135] Figure 11-13 shows that the stiffness range can be divided into "upper tolerance", "target tolerance (middle variance)", and "lower tolerance". These descriptions are for illustrative purposes only and should not be construed as limiting the range in any way. It should not be understood that using the "upper tolerance" in one part (e.g., the penultimate distal portion) requires using the same "upper tolerance" in another part (e.g., the last proximal portion). Thus, as an example, the penultimate distal portion may include stiffness within the upper tolerance range, while the penultimate proximal portion may include stiffness within the target tolerance range. In some examples, any tolerance ranges can be mixed and matched.

[0136] In various examples, the stiffness along the length of the catheter may vary. As previously described, example methods or devices for varying stiffness may include, but are not limited to, using an outer sheath, coils, braided tubular layers, liners, and / or radiopaque markers. In one example, all or a portion of the length of the catheter, including the penultimate distal and distal portions, may be integrally formed as a unit and thus be continuous.

[0137] Claim Library

[0138] Article 1. A catheter, comprising: an elongate catheter body having an outer sheath; a first outer sheath segment located within the distal portion of the elongate catheter body and having a first stiffness; and a second outer sheath segment located proximal to the first outer sheath segment and having a second stiffness lower than the first outer sheath.

[0139] Article 2. The catheter according to Article 1, further comprising a third outer sheath segment located proximal to the second outer sheath segment and having a third stiffness lower than the second outer sheath segment.

[0140] Article 3. The catheter according to Article 2, further comprising a fourth outer sheath segment located proximal to the third outer sheath segment and having a fourth stiffness lower than the third outer sheath segment.

[0141] Article 4. The catheter according to Article 3, wherein the first outer sheath segment includes a hardness value within the range of 20 to 40 Shore A hardness.

[0142] Article 5. The catheter according to Article 4, wherein the second outer sheath segment includes a hardness value within the range of 7 to 18 Shore A hardness.

[0143] Article 6. The catheter according to Article 5, wherein the third outer sheath segment includes a hardness value within the inclusive range of 14 to 25 Shore A.

[0144] Article 7. The catheter according to Article 6, wherein the fourth outer sheath segment includes a hardness value within the inclusive range of 20 to 40 Shore A.

[0145] Article 8. The catheter according to Article 1, wherein the distal portion of the elongate catheter body further comprises coils having a larger pitch near its distal end and a smaller pitch near its proximal end.

[0146] Article 9. The catheter according to Article 8, wherein the larger pitch of the coils is in the range of 0.006 inches to 0.01 inches.

[0147] Article 10. The catheter according to Article 9, wherein the smaller pitch of the coils is in the range of 0.003 inches to 0.0055 inches.

[0148] Article 11. The catheter according to Article 8 further includes a braided nitinol tube disposed on the coil, having a smaller PPI near its distal end and a larger PPI near its proximal end.

[0149] Article 12. The catheter according to Article 11, wherein the smaller PPI is in the range of 55 PPI to 100 PPI.

[0150] Article 13. A catheter comprising: an elongate catheter body; and an outer sheath positioned along the elongate catheter body; wherein a distal region of the outer sheath includes a plurality of sheath segments, the hardness of which decreases towards the distal end of the elongate catheter body and then increases.

[0151] Article 14. The catheter according to Article 13, wherein the most distal sheath segment of the plurality of sheath segments has a higher hardness than the proximally adjacent sheath segment of the plurality of sheath segments.

[0152] Article 15. The catheter according to Article 13, wherein a distal region of the elongate catheter body further includes a coil having a larger pitch near its distal end and a smaller pitch near its proximal end.

[0153] Article 16. The catheter according to Article 15 further includes a braided nitinol tube disposed on the coil, having a smaller PPI near its distal end and a larger PPI near its proximal end.

[0154] Article 17. The catheter according to Article 16, wherein the plurality of outer sheath segments are composed of polyurethane elastomer.

[0155] Article 18. The catheter according to Article 17 further includes a liner forming an internal passage through the catheter; the liner includes a proximal PTFE tube and a distal polyolefin elastomer tube, which are connected by a tube bonded to the distal end of the proximal PTFE tube and the proximal end of the distal polyolefin elastomer tube.

[0156] Article 19. The catheter according to Article 18, wherein the length of the distal polyolefin elastomer tube is in the range of 11 cm to 15 cm, and wherein the length of the proximal PTFE tube is also in the range of 90 cm to 120 cm.

[0157] Article 20. A catheter comprising: a catheter body device; and an outer sheath device for achieving a decrease in hardness towards the distal end of the catheter body and then an increase in hardness.

[0158] Article 21. A catheter, comprising: an elongate catheter body having an outer sheath; a first outer sheath section located within the distal portion of the elongate catheter body and having a first hardness; and a second outer sheath section located near the proximal end of the first outer sheath section and having a second hardness lower than the first outer sheath section.

[0159] Article 22. The catheter according to Article 21, wherein the first outer sheath section comprises a hardness value within the inclusive range of 20 to 40 Shore A.

[0160] Article 23. The catheter according to Article 22, wherein the first outer sheath section comprises a hardness value of 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 or 40 Shore A.

[0161] Article 24. The catheter according to any one of Articles 21 - 23, wherein the second outer sheath section comprises a hardness value of 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18 Shore A.

[0162] Article 25. The catheter according to any one of Articles 21 - 24, further comprising a third outer sheath section located near the proximal end of the second outer sheath section and having a third hardness higher than the second outer sheath section.

[0163] Article 26. The catheter according to any one of Articles 21 - 25, wherein the third outer sheath section comprises a hardness value of 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 or 25.

[0164] Article 27. The catheter according to any one of Articles 21 - 26, further comprising a fourth outer sheath section located near the proximal end of the third outer sheath section and having a fourth stiffness higher than the third outer sheath section.

[0165] Article 28. The catheter according to any one of Articles 21 - 27, wherein the fourth outer sheath section comprises a hardness value of 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39 or 40.

[0166] Article 29. The catheter according to any one of Articles 21 - 28, further comprising a fifth outer sheath section located near the proximal end of the fourth outer sheath section and having a fifth hardness higher than the fourth outer sheath section.

[0167] Article 30. The catheter according to any one of Articles 21 - 29, wherein the fifth outer sheath segment has a hardness value of 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, or 55.

[0168] Article 31. The catheter according to any one of Articles 21 - 30, further comprising a sixth outer sheath segment located near the proximal end of the fifth outer sheath segment and having a sixth hardness higher than that of the fifth outer sheath segment.

[0169] Article 32. The catheter according to any one of Articles 21 - 31, wherein the sixth outer sheath segment has a hardness value of 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, or 65.

[0170] Article 33. The catheter according to any one of Articles 21 - 32, further comprising a seventh outer sheath segment located near the proximal end of the sixth outer sheath segment and having a seventh hardness higher than that of the sixth outer sheath segment.

[0171] Article 34. The catheter according to any one of Articles 21 - 33, wherein the seventh outer sheath segment has a hardness value of 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, or 80.

[0172] Article 35. The catheter according to any one of Articles 21 - 34, wherein the elongated catheter body further comprises a coil having a larger pitch near its distal end and a smaller pitch near its proximal end.

[0173] Article 36. The catheter according to any one of Articles 21 - 35, wherein the larger pitch of the coil is in the range of 0.006 inches to 0.01 inches.

[0174] Article 37. The catheter according to any one of Articles 21 - 36, wherein the larger pitch of the coil is 0.006, 0.007, 0.008, 0.009, or 0.01 inches.

[0175] Article 38. The catheter according to any one of Articles 21 - 37, wherein the smaller pitch of the coil is in the range of 0.003 inches to 0.0055 inches.

[0176] Article 39. The catheter according to any one of Articles 21 - 38, wherein the coil further has an intermediate pitch between a smaller pitch and a larger pitch, and the intermediate pitch is within an inclusive range of 0.003 to 0.008 inches.

[0177] Article 40. The catheter according to any one of Articles 21 - 39, wherein the intermediate pitch is 0.003, 0.004, 0.005, 0.006, 0.007, or 0.008.

[0178] Article 41. The catheter according to any one of Articles 21 - 40, further comprising a braided nitinol tube disposed on the coil, having a smaller PPI near its distal end and a larger PPI near its proximal end.

[0179] Article 42. The catheter according to any one of Articles 21 - 41, wherein the smaller PPI is within an inclusive range of 55 PPI to 100 PPI, and the larger PPI is within an inclusive range of 120 to 145.

[0180] Article 43. The catheter according to any one of Articles 21 - 42, wherein the smaller PPI is 55 PPI, 56 PPI, 57 PPI, 58 PPI, 59 PPI, 60 PPI, 61 PPI, 62 PPI, 63 PPI, 64 PPI, 65 PPI, 66 PPI, 67 PPI, 68 PPI, 69 PPI, 70 PPI, 71 PPI, 72 PPI, 73 PPI, 74 PPI, 75 PPI, 76 PPI, 77 PPI, 78 PPI, 79 PPI, 80 PPI, 81 PPI, 82 PPI, 83 PPI, 84 PPI, 85 PPI, 86 PPI, 87 PPI, 88 PPI, 89 PPI, 90 PPI, 91 PPI, 92 PPI, 93 PPI, 94 PPI, 95 PPI, 96 PPI, 97 PPI, 98 PPI, 99, or 100 PPI.

[0181] Article 44. The catheter according to any one of Articles 21 - 43, wherein the larger PPI is 120 PPI, 121 PPI, 122 PPI, 123 PPI, 124 PPI, 125 PPI, 126 PPI, 127 PPI, 128 PPI, 128 PPI, 130 PPI, 131 PPI, 132 PPI, 133 PPI, 134 PPI, 135 PPI, 136 PPI, 137 PPI, 138 PPI, 139 PPI, 140 PPI, 141 PPI, 142 PPI, 143 PPI, 144, or 145 PPI.

[0182] Article 45. The catheter according to any one of Articles 21 - 44, wherein any outer sheath segment is composed of a polyurethane elastomer.

[0183] Article 46. The catheter according to any one of Articles 21 - 45, further comprising a liner forming an internal passage through the catheter; the liner includes a proximal PTFE tube and a distal polyolefin elastomer tube, which are connected by a tube bond at the distal end of the proximal PTFE tube and the proximal end of the distal polyolefin elastomer tube.

[0184] Article 47. The catheter according to any one of Articles 21 - 46, wherein the length of the distal polyolefin elastomer tube is in the range of 11 cm to 15 cm, and wherein the length of the proximal PTFE tube is in the range of 90 cm to 120 cm.

[0185] Article 48. A catheter, comprising: an elongate catheter body having a liner forming a passage through the catheter; the liner having a proximal portion formed of a first material and a distal portion formed of a second material; a coil disposed on the distal portion of the liner, wherein the coil has a larger pitch near its distal end and a smaller pitch near its proximal end.

[0186] Article 49. The catheter according to Article 48, wherein the catheter transitions from the larger pitch to the smaller pitch at the interface between the first material and the second material of the liner.

[0187] Article 50. The catheter according to any one of Articles 48 - 49, wherein the larger pitch of the coil is in the range of 0.006 inches to 0.01 inches.

[0188] Article 51. The catheter according to any one of Articles 48 - 50, wherein the larger pitch of the coil is 0.006, 0.007, 0.008, 0.009, 0.01 inches.

[0189] Article 52. The catheter according to any one of Articles 48 - 51, wherein the smaller pitch of the coil is in the range of 0.003 inches to 0.0055 inches.

[0190] Article 53. The catheter according to any one of Articles 48 - 52, wherein the coil further has an intermediate pitch between the smaller pitch and the larger pitch, and wherein the intermediate pitch is inclusively in the range of 0.003 to 0.008 inches.

[0191] Article 54. The catheter according to any one of Articles 48 - 53, wherein the intermediate pitch is 0.003, 0.004, 0.005, 0.006, 0.007 or 0.008.

[0192] Article 55. The catheter according to any one of Articles 48 - 54 further includes a braided nitinol tube disposed on the coil, having a smaller PPI near its distal end and a larger PPI near its proximal end.

[0193] Article 56. The catheter according to any one of Articles 48 - 55, wherein the smaller PPI is in the inclusive range of 55 PPI to 100 PPI, and the larger PPI is in the inclusive range of 120 to 145.

[0194] Article 57. The catheter according to any one of Articles 48 - 56, wherein the smaller PPI is 55 PPI, 56 PPI, 57 PPI, 58 PPI, 59 PPI, 60 PPI, 61 PPI, 62 PPI, 63 PPI, 64 PPI, 65 PPI, 66 PPI, 67 PPI, 68 PPI, 69 PPI, 70 PPI, 71 PPI, 72 PPI, 73 PPI, 74 PPI, 75 PPI, 76 PPI, 77 PPI, 78 PPI, 79 PPI, 80 PPI, 81 PPI, 82 PPI, 83 PPI, 84 PPI, 85 PPI, 86 PPI, 87 PPI, 88 PPI, 89 PPI, 90 PPI, 91 PPI, 92 PPI, 93 PPI, 94 PPI, 95 PPI, 96 PPI, 97 PPI, 98 PPI, 99 or 100 PPI.

[0195] Article 58. The catheter according to any one of Articles 48 - 57, wherein the larger PPI is 120 PPI, 121 PPI, 122 PPI, 123 PPI, 124 PPI, 125 PPI, 126 PPI, 127 PPI, 128 PPI, 128 PPI, 130 PPI, 131 PPI, 132 PPI, 133 PPI, 134 PPI, 135 PPI, 136 PPI, 137 PPI, 138 PPI, 139 PPI, 140 PPI, 141 PPI, 142 PPI, 143 PPI, 144 or 145 PPI.

[0196] Article 59. A catheter, comprising: an elongate catheter body having an outer sheath; a first outer sheath section located within the distal portion of the elongate catheter body and having a first hardness value; and a second outer sheath section located proximal to the first outer sheath section and having a second hardness value lower than that of the first outer sheath; wherein the hardness value of the first outer sheath section is 100%, 110%, 120%, 130%, 140%, 150%, 160%, 170%, 180%, 190%, 200%, 210%, 220%, 230%, 240%, 250%, 260%, 270%, 280%, 290%, 300%, 310%, 320%, 330%, 340 or 350% higher than that of the second outer sheath section.

[0197] Article 60. A catheter, comprising: an elongate catheter body having a plurality of layers forming a catheter wall; wherein the catheter wall forms a lumen between the proximal and distal ends of the catheter; and wherein the distal portion of the catheter has increasing flexibility towards the distal end of the catheter and then decreasing flexibility until the distal end of the catheter.

[0198] Article 61. A catheter, comprising: an elongate catheter body; and an outer sheath positioned along the elongate catheter body and having a distal region; wherein the hardness of the distal region decreases towards the distal end of the catheter body and then increases.

[0199] Article 62. The catheter according to Article 61, wherein the distal region increases in hardness within a length extending from the distal end of the catheter body by about 0 to 0.5 cm and the hardness is within an inclusive range of 20A to 40A Shore hardness.

[0200] Article 62. The catheter according to Article 61, wherein the distal region increases in hardness within a length extending from the distal end of the catheter body by about 0 to 3 cm and increases to a hardness within the range of 20A to 40A Shore hardness.

[0201] Article 63. The catheter according to Article 62, wherein the distal region decreases in hardness within a length extending from the distal end of the catheter body by at least about 0.5 to 15 cm and decreases to a hardness within an inclusive range of 12 - 18 Shore A.

[0202] Article 64. A catheter comprising: an elongate catheter body having a distal region with a distal portion and a proximal portion; wherein the stiffness of the distal portion is 100% (i.e., twice), 110%, 120%, 130%, 140%, 150%, 160%, 170%, 180%, 190%, 200%, 210%, 220%, 230%, 240%, 250%, 260%, 270%, 280%, 290%, 300% (i.e., three times), 310%, 320%, 330%, 340%, 350% higher than that of the proximal portion.

[0203] Article 65. A catheter comprising: an elongate catheter body having a distal region and a proximal region; wherein the stiffness of the proximal region is 7000%, 7500%, 8000%, 8500%, 9000%, 9500%, 10000%, 10500%, 11000%, or a percentage value within a range including these percentages that is higher than that of the distal region.

[0204] Article 66. The catheter according to Article 65, wherein the distal region is proximally about 0 to 7 - 12 cm proximal to the distal tip; and wherein the proximal region is between 7 - 12 cm proximal to the distal tip and 40 - 100 cm from the distal end.

[0205] Article 67. A catheter comprising: an elongate catheter body having a distal end; wherein, between the distal end of the catheter and proximally about 10 cm, the average stiffness is between about 2 - 10 gf / mm, between about 10 cm to 13 cm from the distal end, the proximal average stiffness increases by about 9 gf / mm to 39 gf / mm, between about 13 cm to 30 cm from the distal end, between about 29 gf / mm to 480 between the distal end, and between about 30 cm to 40 cm from the distal end, the proximal average stiffness decreases by about 480 gf / mm to 495 gf / mm.

[0206] Article 68. A catheter comprising: an elongate catheter body having an outer sheath; a first outer sheath segment located within the distal portion of the elongate catheter body and having a first stiffness; and a second outer sheath segment located proximally to the first outer sheath segment and having a second stiffness lower than that of the first outer sheath segment.

[0207] Article 69. The catheter according to Article 68, further comprising a third outer sheath segment that abuts the second outer sheath segment proximally and has a third stiffness higher than that of the second outer sheath segment.

[0208] Article 70. The catheter according to Articles 68 - 69 further includes a fourth outer sheath section, which is located near the proximal end of the third outer sheath section and has a fourth stiffness higher than that of the third outer sheath section.

[0209] Article 71. The catheter according to any one of Articles 68 - 70, wherein the first outer sheath section includes a hardness value within the inclusive range of 20 to 40 Shore A.

[0210] Article 72. The catheter according to any one of Articles 68 - 71, wherein the second outer sheath section includes a hardness value within the inclusive range of 7 to 18 Shore A.

[0211] Article 73. The catheter according to any one of Articles 68 - 72, wherein the third outer sheath section includes a hardness value within the inclusive range of 14 to 25 Shore A.

[0212] Article 74. The catheter according to any one of Articles 68 - 73, wherein the fourth outer sheath section includes a hardness value within the inclusive range of 20 to 40 Shore A.

[0213] Article 75. The catheter according to any one of Articles 68 - 74, wherein the elongate catheter body further includes a coil, which has a larger pitch near its distal end and a smaller pitch near its proximal end.

[0214] Article 76. The catheter according to any one of Articles 68 - 75, wherein the larger pitch of the coil is in the range of 0.006 inches to 0.01 inches.

[0215] Article 77. The catheter according to any one of Articles 68 - 76, wherein the smaller pitch of the coil is in the range of 0.003 inches to 0.0055 inches.

[0216] Article 78. The catheter according to any one of Articles 68 - 77 further includes a braided nitinol tube disposed on the coil, which has a smaller PPI near its distal end and a larger PPI near its proximal end.

[0217] Article 79. The catheter according to any one of Articles 68 - 78, wherein the smaller PPI is within the inclusive range of 55 PPI to 100 PPI, and the larger PPI is within the inclusive range of 120 to 145.

[0218] Article 80. A catheter comprising: an elongate catheter body; and an outer sheath positioned along the elongate catheter body, which has a distal region; wherein the hardness of the distal region decreases towards the distal end of the catheter body and then increases until the distal end of the catheter body.

[0219] Article 81. The catheter according to Article 80, wherein the hardness of the distal region increases within a length extending about 0 to 0.5 cm from the distal end of the catheter body and reaches a hardness within the Shore hardness range of 20A to 40A.

[0220] Article 82. The catheter according to Articles 80 - 81, wherein the hardness of the distal region increases within a length extending about 0 to 3 cm from the distal end of the catheter body and increases to a hardness within the Shore hardness range of 20A to 40A.

[0221] Article 83. The catheter according to any one of Articles 80 - 82, wherein the hardness of the distal region decreases within a length of at least about 0.5 to 15 cm extending from the distal end of the catheter body and decreases to a hardness within the Shore A hardness range of 12 - 18.

[0222] Article 84. The catheter according to any one of Articles 80 - 83, wherein the hardness of the distal region increases within a length extending about 0 to 3 cm from the distal end, and the proximal Shore A hardness value within the distal region is doubled or tripled.

[0223] Article 85. The catheter according to any one of Articles 80 - 84, further comprising a liner forming an internal passage through the catheter; the liner includes a proximal PTFE tube and a distal polyolefin elastomer tube, which are connected by a tube connection bonded to the distal end of the proximal PTFE tube and the proximal end of the distal polyolefin elastomer tube.

[0224] Article 86. The catheter according to any one of Articles 80 - 85, wherein the length of the distal polyolefin elastomer tube is in the range of 11 cm to 15 cm, and the length of the proximal PTFE tube is also in the range of 90 cm to 120 cm.

[0225] Article 87. A catheter comprising: a catheter body device; and an outer sheath device for achieving a decrease in hardness towards the distal end of the catheter body and then an increase in hardness.

[0226] Article 88. A catheter comprising: an elongated catheter body; a penultimate distal portion having a first stiffness; and a distal portion having a second stiffness, wherein the second stiffness is greater than the first hardness.

[0227] Article 89. The catheter according to Article 88, wherein the catheter stiffness increases from the first stiffness at about 5 cm from the distal end of the distal portion to the second stiffness at about 30 cm from the distal end of the distal portion.

[0228] Article 90. The catheter according to Articles 88 - 89, wherein the first stiffness is less than 50 gf / mm.

[0229] Article 91. The catheter according to any one of Articles 88 - 90, wherein the second stiffness is greater than 400 gf / mm.

[0230] Article 92. The catheter according to any one of Articles 88 - 91, wherein the increase in stiffness is substantially linear.

[0231] Article 93. The catheter according to any one of Articles 88 - 92, wherein the stiffness at 30 cm from the distal tip is between 100 gf / mm and 400 gf / mm.

[0232] Article 94. The catheter according to any one of Articles 88 - 93, wherein the stiffness at 40 cm from the distal end is between 100 gf / mm and 400 gf / mm.

[0233] Article 95. The catheter according to any one of Articles 88 - 94, wherein the stiffness at 30 cm from the distal tip is between 150 gf / mm and 350 gf / mm.

[0234] Article 96. The catheter according to any one of Articles 88 - 95, wherein the stiffness at 40 cm from the distal tip is between 150 gf / mm and 350 gf / mm.

[0235] Article 97. The catheter according to any one of Articles 88 - 96, wherein the stiffness from 40 cm to 90 cm from the distal tip is between 400 gf / mm and 600 gf / mm.

[0236] Article 98. The catheter according to any one of Articles 88 - 97, wherein the stiffness from 40 cm to 120 cm from the distal tip is between 400 gf / mm and 600 gf / mm.

[0237] Article 99. The catheter according to any one of Articles 88 - 98, further comprising a braided mesh tubular layer extending through at least a portion of the elongated catheter body, the braided mesh tubular layer having a first stiffness along the penultimate distal portion and a second stiffness along the distal portion.

[0238] Article 100. The catheter according to any one of Articles 88 - 99, wherein the braided mesh tubular layer is located within the wall of the catheter.

[0239] Article 101. The catheter according to any one of Articles 88 - 100, wherein the braided mesh tubular layer is located between the outer sheath and the inner coil.

[0240] Article 102. The catheter according to any one of Articles 88 - 101, wherein the braided mesh tubular layer is located below the inner coil.

[0241] Article 103. The catheter according to any one of Articles 88 - 102, wherein the weft density of the braided tubular layer along the first part having a first stiffness is greater than the weft density of the braided tubular layer along the second part having a second stiffness.

[0242] Article 104. The catheter according to any one of Articles 88 - 103, wherein the diameter of the wire forming the braided tubular layer is larger along the second part having a second stiffness than along the first part having a first stiffness.

[0243] Article 105. The catheter according to any one of Articles 88 - 98, further comprising a liner extending through at least a part of the elongated catheter body, the liner having a first stiffness along the penultimate distal part and a second stiffness along the distal part.

[0244] Article 106. The catheter according to Article 105, wherein the liner includes a first section along the penultimate distal part and a second section along the distal part, wherein the first section is composed of a first material having a first hardness and the second section is composed of a second material having a second hardness.

[0245] Article 107. The catheter according to any one of Articles 105 - 106, wherein the first hardness is less than the second hardness.

[0246] Article 108. The catheter according to any one of Articles 105 - 107, wherein the first section is composed of a first material having a first flexibility and wherein the second section is composed of a second material having a second flexibility.

[0247] Article 109. The catheter according to any one of Articles 105 - 108, wherein the first flexibility is greater than the second flexibility.

[0248] Article 110. The catheter according to any one of Articles 105 - 109, wherein the first material is composed of PTFE and the second material is composed of a polyolefin elastomer.

[0249] Article 111. The catheter according to any one of Articles 105 - 110, wherein the first section and the second section are integrally formed by a single body.

[0250] Article 112. A catheter, comprising: an elongated catheter body; and an outer sheath having a distal region positioned along the elongated catheter body; wherein the distal region has a variable hardness, and in the distal direction along the longitudinal axis, the hardness decreases towards the distal end of the catheter body and then increases until the most distal end of the catheter body.

[0251] Article 113. The catheter according to Article 112, wherein the hardness of the outer sheath at the most distal end of the catheter body is between 20A and 50A Shore hardness.

[0252] Article 114. The catheter according to any one of Articles 112 - 113, wherein the hardness of the outer sheath in the portion closest to the distal end of the catheter body is between 10A and 20A Shore hardness.

[0253] Article 115. The catheter according to any one of Articles 112 - 114, wherein the distal region having a variable hardness with a decreasing hardness towards the distal end of the catheter body includes a first outer sheath segment having a first hardness and a second outer sheath segment having a second hardness.

[0254] Article 116. The catheter according to any one of Articles 112 - 115, wherein the interface region has a smooth transition from the first hardness to the second hardness.

[0255] Article 117. The catheter according to any one of Articles 112 - 116, wherein the length of the interface region is at least 0.5 cm.

[0256] Article 118. A catheter, comprising: an elongated catheter body; a proximal portion; an intermediate portion; and a distal portion; wherein the intermediate portion is located between the proximal portion and the distal portion; and wherein the intermediate portion increases between a first stiffness and a second stiffness.

[0257] Article 119. The catheter according to Article 118, wherein the first stiffness is located at the distal end of the intermediate portion and the second stiffness is located at the proximal end of the inner portion.

[0258] Article 120. The catheter according to any one of Articles 118 - 119, wherein the distal end of the intermediate portion is located between about 0.01 cm from the distal end of the distal portion and 15 cm from the distal end of the distal portion.

[0259] Article 121. The catheter according to any one of Articles 118 - 120, wherein the distal end of the intermediate portion is located between about 5 cm from the distal end of the distal portion and 10 cm from the distal end of the distal portion.

[0260] Article 122. The catheter according to any one of Articles 118 - 121, wherein the proximal end of the intermediate portion is located between about 20 cm from the distal end of the distal portion and 40 cm from the distal end of the distal portion.

[0261] Article 123. The catheter according to any one of Articles 118 - 122, wherein the proximal end of the intermediate portion is located between about 25 cm from the distal end of the distal portion and 35 cm from the distal end of the distal portion.

[0262] Article 124. The catheter according to any one of Articles 118 - 123, wherein the distal end of the middle portion is approximately 10 cm away from the distal tip of the distal portion.

[0263] Article 125. The catheter according to any one of Articles 118 - 124, wherein the proximal end of the middle portion is approximately 30 cm away from the distal tip of the distal portion.

[0264] Article 126. The catheter according to any one of Articles 118 - 125, wherein the first stiffness is less than 50 gf / mm.

[0265] Article 127. The catheter according to any one of Articles 118 - 126, wherein the second stiffness is greater than 400 gf / mm.

[0266] Article 128. The catheter according to any one of Articles 118 - 127, wherein the first stiffness is between approximately 1 gf / mm and 100 gf / mm.

[0267] Article 129. The catheter according to any one of Articles 118 - 128, wherein the second stiffness is between approximately 300 gf / mm and 600 gf / mm.

[0268] Article 130. The catheter according to any one of Articles 118 - 129, wherein the second stiffness is at least five times the first stiffness.

[0269] Article 131. The catheter according to any one of Articles 118 - 130, wherein the second stiffness is at least twice the first stiffness.

[0270] Article 132. The catheter according to any one of Articles 118 - 131, wherein the increase between the first stiffness and the second stiffness is substantially linear.

[0271] Article 133. The catheter according to any one of Articles 118 - 132, wherein the increase between the first stiffness and the second stiffness is non - linear.

[0272] Article 134. The catheter according to any one of Articles 118 - 133, wherein the second stiffness is approximately 500 gf / mm.

[0273] Article 135. The catheter according to any one of Articles 118 - 134, wherein the first stiffness is between approximately 2 gf / mm and 10 gf / mm.

[0274] Although the invention has been described in terms of specific embodiments and applications, additional embodiments and modifications can be made by those of ordinary skill in the art in accordance with this teaching without departing from or exceeding the spirit or scope of the claimed invention. Accordingly, it should be understood that the drawings and description herein are provided by way of example to facilitate understanding of the invention and should not be construed as limiting its scope.

Claims

1. A catheter, comprising: An elongate catheter body; A penultimate distal portion having a first stiffness; And A distal portion having a second stiffness, wherein the second stiffness is greater than the first stiffness.

2. The catheter according to claim 1, wherein the length of the distal portion is between 0.01 cm and 5 cm.

3. The catheter according to claim 2, wherein the length of the distal portion is between 0.01 cm and 0.2 cm.

4. The catheter according to claim 1, wherein the stiffness of the elongate catheter body increases from a smaller stiffness at a first point about 10 cm from the distal tip of the distal portion to a larger stiffness at a second point about 30 cm from the distal tip of the distal portion.

5. The catheter according to claim 4, wherein the smaller stiffness is less than 50 gf / mm.

6. The catheter according to claim 5, wherein the larger stiffness is greater than 400 gf / mm.

7. The catheter according to claim 4, wherein the larger stiffness is at least five times greater than the smaller stiffness.

8. The catheter according to claim 4, wherein the increase between the smaller stiffness and the larger stiffness is substantially linear.

9. The catheter according to claim 1, wherein, The stiffness at a point 20 cm proximal to the distal tip of the distal portion is between 100 gf / mm and 400 gf / mm.

10. The catheter according to claim 9, wherein, The stiffness at a point 20 cm proximal to the distal tip of the distal portion is between 150 gf / mm and 350 gf / mm.

11. The catheter according to claim 1, wherein, The stiffness along a segment between 30 cm and 90 cm proximal to the distal tip of the distal portion is between 400 gf / mm and 600 gf / mm.

12. The catheter according to claim 1, wherein, The stiffness along a segment between 30 cm and 120 cm proximal to the distal tip of the distal portion is between 400 gf / mm and 600 gf / mm.

13. The catheter according to claim 1, wherein the penultimate distal portion and the distal portion are integrally formed.

14. The catheter according to claim 1, wherein the penultimate distal portion includes a first outer sheath segment having the first stiffness, and wherein the distal portion includes a second outer sheath segment having the second stiffness.

15. The catheter according to claim 1, further comprising a coil extending through at least a portion of the elongate catheter body, the coil having a first stiffness along the penultimate distal portion and a second stiffness along the distal portion.

16. The catheter according to claim 15, wherein the coil includes a first spacing between the coils along the penultimate distal portion and a second spacing between the coils along the distal portion, the first spacing being less than the second spacing.

17. The catheter according to claim 15, wherein the coil includes a first wire diameter along the penultimate distal portion and a second wire diameter along the distal portion, the first wire diameter being greater than the second wire diameter.

18. The catheter according to claim 1, further comprising a braided network tube layer extending through at least a portion of the elongated catheter body, the braided network tube layer having a first stiffness along the penultimate distal portion and a second stiffness along the distal portion.

19. The catheter according to claim 1, further comprising a liner extending through at least a portion of the elongated catheter body, the liner having a first stiffness along the penultimate distal portion and a second stiffness along the distal portion.

20. A catheter comprising: An elongated catheter body having an outer sheath; A first outer sheath segment located at the most distal portion of the elongated catheter body and having a first stiffness; And, A second outer sheath segment located at the second most distal portion of the first outer sheath segment and having a second stiffness lower than the first stiffness.

21. A catheter comprising: An elongated catheter body; And An outer sheath having a distal region positioned along the elongated catheter body; wherein the distal region has a variable hardness, and in the distal direction along the longitudinal axis, the hardness decreases towards the distal end of the catheter body and then increases until the most distal end of the catheter body.

22. The catheter according to claim 21, wherein the hardness of the outer sheath at the most distal end of the catheter body is between 20A and 50A Shore hardness.

23. The catheter according to claim 22, wherein, The hardness of the outer sheath at a portion near the most distal end of the catheter body is between 10A and 20A Shore hardness.

24. The catheter according to claim 21, wherein, The distal region has a variable hardness with a decreasing hardness towards the distal end of the catheter body, and the distal region includes a first outer sheath segment having a first hardness joined to a second outer sheath segment having a second hardness at an interface region.

25. The catheter according to claim 24, wherein the interface region has a smooth transition from the first hardness to the second hardness.

26. The catheter according to claim 25, wherein the length of the interface region is at least 0.1 cm.

27. A catheter comprising: An elongated catheter body having a distal portion, a proximal portion, and an intermediate portion therebetween; Wherein the distal portion has a first stiffness less than 50 gf / mm, wherein the intermediate portion has a second stiffness, and the proximal portion has a third stiffness greater than 400 gf / mm; Wherein the second stiffness is a variable stiffness range between the first stiffness and the third stiffness; Wherein the intermediate portion extends 7 - 13 cm from the distal tip of the elongated catheter body and 25 - 35 cm from the distal tip.

28. The catheter according to claim 27, wherein the variable range of the second stiffness of the intermediate portion increases at a substantially linear rate in the distal-to-proximal direction.

29. The catheter according to claim 27, wherein, The entire variable range of the second stiffness of the intermediate portion increases at a rate not exceeding 60 gf / mm per centimeter of the catheter body length in the distal-to-proximal direction.

30. The catheter according to claim 27, wherein, The entire variable range of the second stiffness of the intermediate portion increases at a rate of 10 - 60 gf / mm per centimeter of the catheter body length in the distal-to-proximal direction.

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