catheter

Abstract

The catheter has a decreasing stiffness (i.e., increasing flexibility) toward the distal end of the catheter, followed by an increasing stiffness (i.e., decreasing flexibility) toward the distal end. Thus, the distal portion of the catheter, including the distal tip, may have a higher stiffness than the next-to-most distal portion of the catheter immediately proximal to the distal portion. The next-to-most distal portion may have a substantially uniform stiffness before transitioning to the next-to-most proximal portion, where the stiffness increases. The next-to-most proximal portion may transition to a proximal portion having a substantially uniform stiffness that is higher than the stiffness of the remaining portions. Methods for varying stiffness along the length of the catheter can vary, including, but not limited to, various features such as an outer jacket, a coiled wire, a braided tubular mesh layer, an inner coil, and / or radiopaque markers, among others.

Description

[Background technology]

[0001] A catheter is an elongated medical device used to aid in accessing and / or treating a site within a patient's body, such as a blood vessel or other cavity. In some cases, a catheter may be advanced through a patient's blood vessels. Often, such catheters must be relatively long to reach a desired target location within the patient's body. Depending on the purpose, such catheters may need to be relatively small in diameter or relatively large in diameter.

[0002] In either of these cases, it is generally desirable for the catheter to have both sufficient flexibility to navigate tortuous vascular passageways without damaging the vessel, and good "pushability" to allow forward movement and rotation to occur without kinking or damaging the catheter. In this regard, considerations of the appropriate balance of stiffness and flexibility may vary based on the length and diameter of the catheter required for a particular application. Summary of the Invention

[0003] This specification relates generally to structural features of catheters, and more particularly to structural features that provide desired flexibility and pushability with reduced kinking.

[0004] One aspect of the present disclosure is directed to a catheter that has a decreasing stiffness (i.e., increasing flexibility) toward the distal end of the catheter and then an increasing stiffness (i.e., decreasing flexibility) toward the distal end. For example, the distal region of the catheter may have a decreasing stiffness in the distal direction, while portions of the catheter near or closest to the distal end may have an increasing stiffness.

[0005] In one example, the catheter may have a distal region including a first region (e.g., length) of the catheter having a single flexibility of a first value and a second region (e.g., length) distal to the first region having a single flexibility of a second value that is less than the first value (i.e., stiffer than the first value).

[0006] In another example, the catheter may have a first region (e.g., a length of the catheter) that has a gradually increasing flexibility (i.e., decreasing stiffness) distally. In this regard, the proximal end of the first region has a lower flexibility than the distal end of the first region. The second region (e.g., a length of the catheter) may be located distal to the first region and may have either a uniform flexibility or a gradually increasing flexibility distally. In either case, at least one portion of the second region may have a lower flexibility than the least flexible portion of the first region. For example, if the second region has a uniform flexibility, that portion may be less flexible than one or all of the distal, middle, or proximal ends of the first region. If the second region has a gradually decreasing flexibility, one or all of the portions within the second region may be less flexible than one or all of the distal, middle, or proximal ends of the first region.

[0007] In another example, the catheter may have at least a proximal portion (i.e., the most proximal portion), a second most distal portion (i.e., the second most distal portion), and a distal portion (i.e., the most distal portion). The proximal portion, the second most distal portion, and / or the distal portion may each have a uniform stiffness and / or a stiffness that varies along at least a portion of their respective lengths. The second most distal portion may be disposed between the proximal and distal portions. The distal portion may have a stiffness greater than the second most distal portion, such that the distal tip of the catheter has a stiffness greater than at least a portion of the second most distal portion.

[0008] In another example, the catheter may include at least a distal section, a second-most distal section, a second-most proximal section (i.e., the second-most proximal section), and a proximal section. The stiffness of the distal section may be greater than the stiffness of the second-most distal section. The stiffness of the second-most proximal section may be greater than the stiffness of the second-most distal section, with the stiffness increasing along the length of the second-most proximal section. The stiffness of the proximal section may be substantially uniform.

[0009] The flexibility / stiffness of the catheter, particularly the distal region of the catheter, may be defined using one or more of the following characteristics:

[0010] In a first example, the stiffness of the outer jacket or sleeve of the catheter may be configured with regions of different hardness or flexibility. The outer jacket may have multiple distinct segments or regions configured with materials of different hardness and / or flexibility. This may be achieved by using different materials in different segments / regions and / or by applying different thicknesses to different segments / regions. Alternatively, the outer jacket may be formed of a single continuous segment / region of varying hardness and / or flexibility (e.g., by blending materials in different regions or by increasing or decreasing the jacket thickness in different regions when molding or extruding the tubular outer jacket).

[0011] In a second example, the stiffness / flexibility of the catheter may be varied by changing the properties of a coiled wire disposed within the catheter wall (e.g., beneath the outer jacket) and extending through at least the distal region of the catheter. Flexibility can be increased or decreased by increasing or decreasing the spacing between individual coils of the wire. Alternatively or additionally, flexibility can be decreased or decreased by increasing or decreasing the thickness / diameter of the wire. Thus, the spacing between the coils may initially increase and then decrease distally, and / or the diameter of the wire may initially decrease and then increase distally. Alternatively or additionally, the coiled wire may be constructed of two or more components with different flexibility, and these components may be interconnected (e.g., by welding) to vary flexibility along the length of the coiled wire.

[0012] In a third example, the stiffness / flexibility of the catheter may be varied by varying the properties of a braided mesh tubular layer disposed within the catheter wall (e.g., between the outer jacket and inner coil, or underneath the inner coil). The braided mesh may be made less flexible by increasing the number of picks per inch, or more flexible by decreasing the number of picks per inch. Alternatively or additionally, the braided mesh may be made less flexible by increasing the wire thickness, or more flexible by decreasing the wire thickness. Alternatively or additionally, the braided mesh tubular layer may be constructed of two or more materials with different flexibility properties that are woven together to provide a varying flexibility along the length of the braided mesh tubular layer. Alternatively or additionally, the braided mesh tubular layer may be made to have a varying flexibility along the length of the braided mesh tubular layer by using two or more braid patterns with different flexibility properties.

[0013] In a fourth example, the stiffness / flexibility of a catheter may be varied by varying the properties of the catheter's inner liner, which may form the catheter's inner lumen or passageway between the proximal and distal ends of the catheter. The inner liner may be formed of two or more tubular sections composed of materials of different hardness or flexibility. In some examples, the liner may be formed of a first tubular section made of a first material (e.g., PTFE) and a second tubular section connected distally to the first tubular section and made of a second material that is softer or more flexible than the first material (e.g., a polyolefin elastomer). In another example, a third tubular section connected distally to the second tubular section may be made of either the first material or a different third material that is harder or less flexible than the second material. In another example, the liner may not have separate attached tubular sections, but instead may be formed as a single tubular member with a gradation in hardness or flexibility, such as by gradating the amount or combination of different materials with different hardnesses, or by varying the thickness of the liner in various regions (e.g., thinner regions have greater flexibility than thicker regions).

[0014] In a fifth example, a radiopaque marker may extend from the distal end of the catheter to form a distal tip. The radiopaque marker may be integral with or attached to the catheter body. The radiopaque marker may be constructed of a material having a higher hardness or lower flexibility than the penultimate distal portion of the catheter from which the radiopaque marker extends.

[0015] In a sixth example, the distal section or tip may be constructed in part using a polymer blend or resin having a radiopaque material, such as barium sulfate or tantalum mixed with the polymer. The radiopaque material may be added to the polymer blend or resin before or during the extrusion process. This provides radiopaque properties to the distal section or tip, allowing a user or operator to visualize the catheter tip during use, without significantly changing the material properties (e.g., stiffness, hardness) of the catheter's distal section or tip. [Brief explanation of the drawings]

[0016] These and other aspects, features and advantages of the present invention will become apparent and elucidated from the following description of embodiments of the invention, which proceeds with reference to the accompanying drawings.

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

[0018] [Figure 2] FIG. 2 is a side view of an example inner liner of the catheter of FIG.

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

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

[0021] [Figure 5] FIG. 5 is a side view of an example outer jacket of the catheter of FIG. 1.

[0022] [Figure 6] FIG. 6 is a side view of an example catheter hub of the catheter of FIG. 1.

[0023] [Figure 7] FIG. 7 is a perspective cross-sectional view of an example of the braided layer and outer jacket layer of the catheter of FIG. 1.

[0024] [Figure 8] FIG. 8 is a graph of catheter stiffness according to an example.

[0025] [Figure 9] FIG. 9 is a graph of catheter stiffness according to an example.

[0026] [Figure 10] FIG. 10 is a graph of catheter stiffness according to an example.

[0027] [Figure 11] FIG. 11 is a graph of catheter stiffness according to an example.

[0028] [Figure 12] FIG. 12 is a graph of catheter stiffness according to an example.

[0029] [Figure 13] FIG. 13 is a graph of catheter stiffness according to an example.

[0030] [Figure 14] FIG. 14 illustrates types I, II, and III aortic arches. DETAILED DESCRIPTION OF THE INVENTION

[0031] Specific embodiments of the present invention will now be described with reference to the drawings. However, the present invention can be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. The terminology used in the detailed description of the embodiments shown in the accompanying drawings is not intended to limit the present invention. In the drawings, like numbers refer to like elements.

[0032] While various embodiments and examples may be described herein, it is specifically contemplated that any of the features of the various embodiments and examples may be combined with one another in any combination. In other words, the features of the various embodiments and examples may be mixed and matched with one another. Thus, although every permutation of the features of the various embodiments and examples may not be explicitly set forth, the specification is intended to encompass every such combination.

[0033] The terms stiffness, hardness, and flexibility are each used herein to describe catheter properties. Generally, as stiffness or hardness increases, flexibility decreases. Thus, while one of these terms may be used in various places in this specification, the relationship between the other terms should also be understood.

[0034] The terms distal and proximal are used herein. Distal generally refers to a direction or region toward or near the working end of the catheter (e.g., the end that is advanced to a target location within a patient). Proximal generally refers to a direction or region that remains outside the patient's body and / or closer to the physician.

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

[0036] This specification is directed generally to structural features of catheters, and specifically to structural features that provide desired flexibility and pushability with reduced kinking.

[0037] The structural features and other aspects described herein may be applied to catheters of any style, size, and / or use within the human body.

[0038] One example of a catheter style that can benefit from the structural features and other aspects described herein is a so-called "88" catheter, i.e., a catheter having an internal lumen passageway with a diameter of approximately 0.088 inches. Currently, such catheters may be among the larger lumen diameter catheters sold for stroke treatment (e.g., as opposed to 5 French (1.667 mm) and 6 French (2 mm) catheters) and are frequently used as access catheters for the treatment, removal, or thrombectomy of blood clots. In some uses, the larger lumen diameter allows a balloon catheter or clot retrieval device to be advanced through the catheter's lumen to a desired location, allowing the clot to be disrupted, captured, and retrieved within the lumen. Thus, the larger diameter may be useful for accommodating larger medical implants and / or devices, such as balloon catheters, clot retrieval devices, or the blood clot itself.

[0039] These relatively large 0.088 inch diameter lumens may also be useful for aspirating blood clots. The distal tip of the catheter can be advanced close to the clot and suction / vacuum applied to the catheter lumen, causing the clot to be drawn into the lumen and removed from the patient's vessel. In addition to the 0.088 inch diameter lumen example, other sizes greater than 5 French or 6 French, such as catheters having an internal lumen passageway with a diameter of 0.092 inches (2.3368 mm), may provide similar advantages and benefits.

[0040] The middle cerebral artery (MCA) is the artery most commonly involved in acute stroke. It branches directly off the internal carotid artery and consists of four major branches: M1, M2, M3, and M4. These vessels supply the brain's frontal, temporal, and parietal lobes, as well as parts of the caudate, internal capsule, and thalamus. Due to their size and location, clots in the M1 and M2 regions of the MCA are most commonly treated with clot retrieval devices and / or aspiration; therefore, a 0.088-inch lumen catheter can be useful in providing optimal treatment for this region.

[0041] To access the brain, physicians typically access a patient's vascular system through the patient's lower extremities (e.g., the femoral artery in the groin). Access to the radial artery, for example, near the patient's wrist, is also possible. Furthermore, the MCA and the vessels accessing it tend to be relatively tortuous. Therefore, such catheters must be relatively long, able to be pushed without kinking, and retain flexibility for advancement into the MCA, which can be difficult to achieve because high flexibility tends to increase the risk of kinking. Furthermore, relatively large 0.088-inch lumen catheters typically have a relatively robust and therefore rigid structure due to their increased size and to prevent the lumen from collapsing during use, particularly when under negative or vacuum pressure during aspiration. Therefore, providing a structure that meets these structural and flexibility requirements can be difficult with these relatively large 0.088-inch lumen catheters.

[0042] In this regard, the present specification provides several different aspects of catheter construction that may be useful in achieving a balance between flexibility and pushability in catheters of all sizes (e.g., 5 French and 6 French), but particularly in 0.088 size catheters.

[0043] One aspect of the present disclosure is directed to catheters that have a decreasing stiffness (i.e., increasing flexibility) toward the distal end of the catheter and then an increasing stiffness (i.e., decreasing flexibility) toward the distal end. For example, the distal region of the catheter may have a predominantly decreasing stiffness distally, but an increasing stiffness near or closest to the distal end of the catheter, such that the distal portion of the catheter has a higher stiffness than the penultimate distal portion of the catheter immediately adjacent to the distal portion.

[0044] Typically, most catheters have a relatively stiff proximal region and a decreasing stiffness toward the distal end of the catheter to some extent, however, decreasing the stiffness distally and then increasing the stiffness near the distal end of the catheter may provide certain advantages in some applications.

[0045] For example, regions of reduced stiffness may provide increased flexibility in the majority of the distal region of the catheter, thereby allowing it to be maneuvered through tortuous vascular pathways, while regions of increased stiffness closer to the distal end of the catheter may be useful in preventing the catheter lumen from collapsing, particularly when using the catheter with suction through its lumen (e.g., when under vacuum, against a vessel sidewall that turns around a tight bend in a tortuous vasculature, or when encountering a stenotic region).

[0046] The region of increased stiffness may also improve performance when aspirating a blood clot in some situations. For example, when a blood clot is pulled by suction through the lumen of the catheter, the stiffer end region may better cut or remove the clot from the blood vessel. Furthermore, the distal end of the catheter may be more resistant to bending or applying suction to non-clotted structures (e.g., portions of a blood vessel). This may be particularly useful in larger sized catheters, such as 0.088 inch catheters, but may also be beneficial in other sized catheters.

[0047] For clot removal in cerebral vessels such as the MCA, regions of increased catheter stiffness can enable better navigation through tortuous or branching vessel pathways. While the distal region remains relatively flexible for the most part, increased stiffness near the end of the catheter can be advantageous for steering the catheter into desired branching or twisting vessel regions. In other words, the additional stiffness can be useful for improving pushability without kinking very close to the distal end of the catheter.

[0048] The reduction in stiffness (relative to the proximal region of the catheter) followed by an increase in stiffness along the distal region of the catheter may include various ways of quantifying, defining, or structuring such flexibility. In this regard, it is noted that the distal region of the catheter may be considered to have discrete, distinct regions or lengths having different stiffness / flexibility relative to adjacent regions, or the distal region may have a continuous increase and / or decrease in flexibility. Thus, when referring to the flexibility / stiffness of different regions or lengths, such descriptions may include regions of uniform flexibility / stiffness or regions of average flexibility / stiffness.

[0049] In one example, a catheter may have a distal region comprising a first region (e.g., length) of the catheter having a single flexibility of a first value and a second region (e.g., length) distal to the first region having a single flexibility of a second value that is less than the first value (i.e., stiffer than the first value).

[0050] In one example, the catheter may include a proximal section, a penultimate distal section, and a distal section. The penultimate distal section may be disposed between the proximal section and the distal section. Thus, the penultimate distal section may be distal to the proximal section and proximal to the distal section. The flexibility of each of the proximal section, the penultimate distal section, and / or the distal section may be uniform along their respective lengths and / or vary along their respective lengths. The flexibility of the distal section may be less than the flexibility of the penultimate distal section, such that the distal section is stiffer than the penultimate distal section.

[0051] In another example, the catheter may have a first region (e.g., a length of the catheter) that has a gradually increasing flexibility (i.e., decreasing stiffness) distally. In this regard, the proximal end of the first region may have a lower flexibility than the distal end of the first region. The second region (e.g., a length of the catheter) may be located distal to the first region and may have a uniform flexibility or a gradually decreasing flexibility. In either case, at least a portion of the second region may have a lower flexibility than the lowest flexibility of the first region. For example, if the second region has a uniform flexibility, the second region may be less flexible than one or all of the distal, middle, and proximal ends of the first region. If the second region has a gradually decreasing flexibility, some or all locations within the second region may be less flexible than one or all of the distal, middle, and proximal ends of the first region.

[0052] In any of the aforementioned examples having either a uniform or gradually increasing / decreasing flexibility region, the second region of increased flexibility may extend to the end of the catheter. Alternatively, an additional third region may be positioned distal to the second region and extend to the end of the catheter. The third region may have increased, decreased, gradually increasing, gradually decreasing, or the same flexibility as the second region (or one or more locations within the second region). The first region in these examples may have a length within a range of about 0.5 to 3 cm (e.g., 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 cm, or any value therebetween). In another example, the length of the first region is greater than 3 cm (e.g., up to 15 cm), and such lengths have been found to be useful for peripheral or cardiac applications in addition to neurovascular applications.

[0053] The flexibility / stiffness of the catheter, particularly the distal region of the catheter, can be configured in a variety of ways using a variety of different features, including but not limited to one or more of the following features:

[0054] In a first example, the stiffness of the catheter's outer jacket or sleeve may be configured with regions of different hardness (e.g., durometer) or flexibility. The outer jacket may have multiple separate segments or regions configured with materials of different hardness and / or flexibility. This may be achieved by using different materials and / or applying different thicknesses to different segments / regions. Alternatively, the outer jacket may be formed with a single continuous segment / region of varying hardness and / or flexibility (e.g., by blending materials in different regions or increasing or decreasing the jacket thickness in different regions when molding or extruding the tubular outer jacket). Alternatively, the thickness variation may be achieved by variable-speed dip coating.

[0055] In a second example, the stiffness / flexibility of the catheter may be varied by altering the properties of the coiled wire disposed within the catheter wall (e.g., under the outer jacket) and extending through at least the distal region of the catheter. Increasing or decreasing the spacing between individual coils of the wire can increase or decrease flexibility. Alternatively, or in addition, increasing or decreasing the thickness / diameter of the wire can decrease flexibility. Thus, the spacing within the coils may initially gradually increase and then decrease distally, and / or the diameter of the wire may initially decrease and then increase distally. Alternatively, or in addition, the coiled wire may be composed of two or more components with different flexibility, which may be interconnected (e.g., by welding) to vary flexibility along the length of the coiled wire. In some embodiments, the material of the coiled wire may be nitinol (e.g., a metal alloy of nickel and titanium). In one example, the distal region 118A and / or one or more other regions of the coil layer 118 may be made of nitinol material. In this example, applying a nitinol material along the distal region of the coiled wire can increase the stiffness of the catheter along the distal region relative to other regions of the catheter that do not incorporate the nitinol material in the respective regions of the coiled wire. As a result, the increased stiffness along the distal region of the catheter can result in reduced kinking, and the catheter can experience improved mechanical hysteresis as the catheter is advanced to a target location within a patient. In some embodiments, one or more regions of the coiled wire can be heat-treated to achieve specific mechanical properties. In one example, the distal region 118A and / or one or more other regions of the coil layer 118 can be heat-treated to achieve a desired hardness and / or flexibility. In this example, heat-treating the coiled wire along the distal region of the coiled wire can increase the stiffness of the catheter along its distal end (relative to other regions that are not heat-treated).This allows for reduced kinking and the catheter has improved mechanical hysteresis.

[0056] In a third example, the stiffness / flexibility of the catheter may be varied by changing the properties of a braided mesh tubular layer disposed within the catheter wall (e.g., between the outer jacket and inner coil, or underneath the inner coil). The braided mesh may be made less flexible by increasing the number of picks per inch, or more flexible by decreasing the number of picks per inch. As an example of definition, picks per inch is the number of times the wires in the braid cross each other along the longitudinal axis per inch of length. Alternatively or additionally, the wires forming the braided mesh may be made thicker to decrease flexibility, or thinner to increase flexibility. Alternatively or additionally, the braided mesh tubular layer may be composed of two or more materials with different flexibility properties that are woven together to provide varying flexibility along the length of the braided mesh tubular layer. Alternatively or additionally, the braided mesh tubular layer may be made of two or more materials with different flexibility properties that are woven together to provide varying flexibility along the length of the braided mesh tubular layer. Alternatively or additionally, the braided mesh tubular layer may be made of two or more braid patterns with different flexibility properties to provide varying flexibility along the length of the braided mesh tubular layer. In some embodiments, the material of the braided mesh can be nitinol (e.g., a metal alloy of nickel and titanium). In one example, the distal region of the braided mesh and / or other regions of the braided mesh can be made of nitinol material. In some embodiments, incorporating nitinol material along the distal region of the braided mesh can increase the stiffness of the catheter, which can reduce kinking and provide improved mechanical hysteresis when the catheter is advanced to a target location within a patient.

[0057] In a fourth example, the stiffness / flexibility of a catheter may be varied by varying the properties of the catheter's inner liner, which may form the catheter's inner lumen or passageway between the proximal and distal ends. The inner liner may be formed of two or more tubular sections composed of materials of different hardness or flexibility. In some examples, the liner may be formed of a first tubular section of a first material (e.g., PTFE) and a second tubular section connected distally to the first tubular section and formed of a second material that is softer or more flexible than the first material (e.g., a polyolefin elastomer). In another example, a third tubular section connected distally to the second tubular section may be formed of either the first material or a different third material that is harder or less flexible than the second material. In another example, the liner may not have separate tubular sections that are joined together, but instead may be formed as a single tubular member with a gradation in hardness or flexibility, such as by gradating the amount or combination of different materials with different hardnesses, or by varying the thickness of the liner in various regions (e.g., thinner regions have greater flexibility than thicker regions).

[0058] In a fifth example, a radiopaque marker may extend from the distal end of the catheter to form a distal tip. The radiopaque marker may be integral with or attached to the catheter body. The radiopaque marker may be constructed of a material having a higher hardness or lower flexibility than the penultimate distal portion of the catheter immediately adjacent from which the radiopaque marker extends.

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

[0060] In some instances, the length of the catheter including the regions of increased flexibility and decreased flexibility is located within a distal portion of the catheter, which may generally extend between the distal end of the catheter and about 10 cm to 40 cm proximally (e.g., 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40 cm, or any length therebetween).

[0061] The distal section may have an increased flexibility and then decreased flexibility extending distally along its length, beginning at the proximal end of the distal section. In one example, the region of decreased flexibility may be located between 0.5 cm and 5 cm from the distal end of the catheter. For example, the length may be 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 cm, or any value therebetween.

[0062] In another embodiment of the invention, the stiffness of the catheter may be increased significantly along the proximal region relative to the distal region. For example, the distal region may be between about 0 cm and about 12 cm from the distal tip and have an average stiffness value of about 5 gf / mm, while the proximal region may be between 12 cm and at least 40 cm and have an average stiffness value of 400-600 gf / mm. In some examples, the proximal region may increase in stiffness relative to the distal region by 7000-11000 percent (e.g., 7000, 7500, 8000, 8500, 9000, 9500, 10000, 10500, 11000 percent, and percentages therebetween or near these percentages). These stiffness values ​​may include the increase in stiffness at the distal end of the catheter described above, or may not include such a feature (i.e., the stiffness at the distal end may decrease or remain constant).

[0063] These structural features may also be applicable to catheters of any style, size, and / or application (e.g., 5 French or 6 French catheters), but may be particularly beneficial for catheters having a 0.088 inch lumen diameter and a working length (i.e., length not including the catheter hub) of approximately 100 cm to 135 cm (e.g., 115 cm or 125 cm). As previously mentioned, smaller diameter catheters (e.g., 5 French or 6 French) are often able to remain relatively flexible throughout their length without kinking or collapse of their lumens due to their smaller diameter. However, larger diameter catheters, such as 0.088 inch lumen catheters, often require greater reinforcement to prevent kinking and / or collapse of their lumens. This can result in a relatively stiff catheter overall, which may be undesirable when accessing delicate and tortuous vessels, such as those in the brain (e.g., the MCA). In that regard, example structures herein may be useful in creating catheters with a relatively stiff proximal region (e.g., an average flexibility of about 400-600 gf / mm) and a relatively flexible distal region (e.g., an average flexibility of about 350-3 gf / mm). Such flexibility may be achieved, for example, by incorporating one or more of the inner liner, coil layer, braid layer, and outer jacket layer described herein, including values ​​for various aspects of each layer, such as material, hardness, coil spacing, wire diameter, braid picks per inch, section length, and other features further described herein.

[0064] Figures 1-7 illustrate various aspects of an example catheter 100 that provides desirable flexibility and pushability and has structural features that reduce kinking. An example of this flexibility is shown in Figures 8 and 9, comparing a 0.088 inch lumen diameter catheter 100 (labeled Catheter B) with a standard 6 French lumen catheter (labeled Catheter A). Further examples of flexibility are shown in Figures 10-12.

[0065] FIG. 10 illustrates that the overall length of the catheter may vary (e.g., 100 cm to 200 cm, although in some cases the overall length may be less than 100 cm or greater than 200 cm), and that the stiffness or flexibility of the proximal portion (e.g., approximately 30 cm to 40 cm from the distal tip to the proximal end) may be substantially uniform.

[0066] Figure 11 shows an example of a non-limiting range of stiffness values ​​along the length of the catheter where stiffness is increased. While this section is illustrated as being between about 15 cm and about 30 cm from the distal tip, it should be understood that the location of this stiffness-increasing section may vary in various examples and therefore should not be construed as being limited to the exact values ​​shown in the figure. Furthermore, the effective length of the stiffness-increasing section may also vary and should not be construed as being limited by the illustrated example. For example, the stiffness-increasing section may be located between about 10 cm and about 40 cm from the distal tip, between about 5 cm and about 35 cm from the distal tip, between about 15 cm and about 30 cm from the distal tip, etc.

[0067] Figure 12 shows a non-limiting example of a range of stiffness values ​​along the penultimate distal section of the catheter length, where the stiffness is initially uniform and then begins to increase. While this section is shown as being between about 5 cm and about 15 cm from the distal tip, it should be understood that the location of the penultimate distal section may vary in various examples and should therefore not be construed as being limited to the exact value shown. For example, the penultimate distal section may be considered to begin 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, depending on the length of the stiffer distal section. In some examples, such as when the stiffer distal section is greater than 5 cm in length, the penultimate distal section may be considered to begin more than 5 cm from the distal tip.

[0068] 11-12 each show a range of stiffness measured in gf / mm. More specifically, FIGS. 11-12 illustrate that the respective stiffnesses along the length of the catheter may vary, and include sections labeled "upper variance," "middle variance," and "lower variance." Thus, it should be understood that the actual values ​​of stiffness along various segments of the catheter's length may vary and, in some instances, may fall outside the illustrated ranges, which are for illustrative purposes only.

[0069] It should be noted that the above data points are examples or estimates of some configurations according to this specification and not necessarily all examples / embodiments.

[0070] As can be seen from these figures, a standard 6 French lumen catheter A generally remains flexible over most of its length, with the proximal portion having an average stiffness of about 180-190 gf / mm, and increasing in flexibility towards its distal end to an average stiffness of 6-2 gf / mm. The relatively small lumen diameter allows it to be very flexible yet resistant to collapse.

[0071] The exemplary 0.088 inch lumen diameter catheter B generally has relatively low flexibility over most of its length, with the proximal section having an average stiffness of about 400-600 gf / mm, or about 500 gf / mm, and increasing in flexibility toward its distal end, reaching an average stiffness of about 350-2 gf / mm, or about 5-2 gf / mm. Such stiffness characteristics, which may be achieved using structural elements described further below, also resist kinking and collapse of the catheter lumen.

[0072] As shown in Figure 1, catheter 100 may generally have a working length including a distal portion or length 100A and a proximal portion or length 100B. The proximal end of proximal portion 100B is connected to catheter hub 106 and strain relief sleeve 106A (also shown in Figure 6), and the distal end of distal portion 100A may optionally include radiopaque markers 108 located either on the exterior of catheter 100 or within the wall of catheter 100. Catheter 100 may include a lumen that opens proximally at catheter hub 106, extends through proximal portion 100B, distal portion 100A, and opens at the distal end of catheter 100.

[0073] The catheter may include at least several different layers that make up its wall. Specifically, the catheter may include an inner liner 110 (FIG. 2) that forms the inner surface of the catheter lumen, a coil layer 116 disposed around the inner liner 110, a braided layer 120 disposed around the coil layer 116, and an outer jacket 102 disposed around the braided layer 120. Alternatively, the positions of the coil layer 116 and the braided layer 120 may be interchanged, i.e., reversed. Alternatively, in some examples, one of the coil layer 116 and the braided layer 120 may be omitted.

[0074] Returning to FIG. 2 , the inner liner 110, in one example, may include a proximal tubular portion 112 and a distal tubular portion 114, which may be connected to one another or extruded / molded as a single tube. If two separate tubes are used, the distal end of the proximal tubular portion 112 and the proximal end of the distal tubular portion 114 may be connected to one another in various ways, such as with adhesive, heating / melting, and / or another component. In the example of FIG. 2 , a bonding layer 116 in the form of a third tube may be disposed around both ends. The bonding layer 116 may be a single, integral tube, or may be comprised of a first tubular member 116A and a second tubular member 116B, each beveled at a complementary angle so that the cut surfaces meet and are connected via adhesive. Additional adhesive may be applied between both members 116A, 116B and portions 114, 112, respectively.

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

[0076] The tie layer 116, and therefore the interface between the two sections 112, 114, may be located within 8-20 cm of the distal end of the catheter 100. For example, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 cm, or any value therebetween. Figure 5 shows an example of the location of the tie layer 116 relative to a portion of the outer jacket 102 in the distal section 100A.

[0077] The coil layer 118 may be disposed about the inner liner 110, as shown in FIG. 3 and indicated by the location of the tie layer 116. The coil layer 118 may extend to the very distal end of the catheter 100 or may terminate a short distance (e.g., 0.5, 1.0, 1.5, or 2.0 cm from the distal end) before the distal end of the catheter 100. The coil layer 118 may be constructed of coiled wire with a varying pitch in different regions or lengths. Generally, the coil layer 118 will have increasing flexibility in the distal direction, although the coil layer 118 may have decreasing flexibility near its distal end, if desired.

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

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

[0080] Distal region 118C may have a length 118F in the range of 95-120 cm (e.g., 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120 cm, or any value therebetween).

[0081] The flexibility of the coil layer 118 may be adjusted by spacing the individual coils of the layer (e.g., larger spacing increases flexibility), by varying the diameter of the wire (e.g., smaller diameter increases flexibility), and / or by using a material with a particular flexibility. In one example, the coil layer 118 is formed from a relatively soft nitinol wire or a relatively stiffer stainless steel wire than nitinol wire.

[0082] In one example, intermediate region 118B has greater flexibility than proximal region 118C, and distal region 118A has greater flexibility than intermediate region 118B. In such an example, the individual loops in proximal region 118C may be spaced apart from one another within a range of approximately 0.003 inches to 0.0055 inches (e.g., 0.003, 0.0035, 0.004, 0.0045, 0.005, 0.0055 inches, or any value therebetween). The individual loops in intermediate region 118B may be spaced apart from one another within a range of approximately 0.005 inches to 0.007 inches (e.g., 0.005, 0.0055, 0.006, 0.0065, 0.007, 0.0075, 0.008 inches, or any value therebetween). The individual loops in the distal region 118A may be spaced apart within a range of about 0.006 inches to 0.010 inches (e.g., 0.006, 0.0065, 0.007, 0.0075, 0.008, 0.009, 0.0095, 0.001 inches, or any length value therebetween).

[0083] In another example, intermediate region 118B has greater flexibility than proximal region 118C, and distal region 118A has greater flexibility than intermediate region 118B. In such an example, the individual loops in proximal region 118C may be spaced apart from one another within a range of approximately 0.003 inches to 0.0055 inches (e.g., 0.003, 0.0035, 0.004, 0.0045, 0.005, 0.0055 inches, or any value therebetween). The individual loops in intermediate region 118B may be spaced apart from one another within a range of approximately 0.005 inches to 0.007 inches (e.g., 0.005, 0.0055, 0.006, 0.0065, 0.007, 0.0075, 0.008 inches, or any value therebetween). The individual loops of distal region 118A may be spaced apart from one another within a range of approximately 0.003 inches to 0.0055 inches (eg, 0.003, 0.0035, 0.004, 0.0045, 0.005, 0.0055 inches, or any value therebetween).

[0084] The braided layer 120, best seen in FIG. 4, may be disposed around or underneath the coil layer 110. The braided layer 120 may extend to the very distal end of the catheter 100, terminate a short distance (e.g., 0.5, 1.0, 1.5, or 2.0 cm from the distal end) before the distal end of the catheter 100, or extend all the way to the beginning of the catheter hub 106 (FIG. 6). The braided layer 120 may be comprised of one or more wires woven together. Generally, the braided layer 120 provides increased flexibility in the distal direction, although the braided layer 118 may have reduced flexibility near its distal end, if desired.

[0085] In one example, braided layer 120 may have a distal region 120A, an intermediate region 118B, and a proximal region 118C. Distal region 120A may have a length in the range of 9 cm to 12 cm (e.g., 9, 9.5, 10, 10.5, 11, 11.5, 12 cm, or any value therebetween). Intermediate region 120B may have a length in the range of 1.5 cm to 3 cm (e.g., 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0 cm, or any value therebetween). If desired, both distal region 120A and intermediate region 120B may have approximately the same length as distal region 118A and intermediate region 118B of coil layer 118 (eg, a combined length of about 10.5 cm).

[0086] Distal region 120C may have a length in the range of 95-120 cm (e.g., 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120 cm, or any value therebetween).

[0087] The flexibility of braided layer 120 may be adjusted by varying the braid density or picks per inch of the braid (higher picks per inch reduces flexibility), varying the wire diameter (e.g., smaller diameter increases flexibility), and / or using materials with specific flexibility. In one example, braided layer 120 is formed from one or more braided nitinol wires, which are relatively soft, or one or more stainless steel wires, which are relatively stiffer than the nitinol wires. In one example, stiffer braided stainless steel wire regions can be secured to more flexible nitinol wire regions.

[0088] In one example, intermediate region 120B has greater flexibility than proximal region 120C, and distal region 120A has greater flexibility than intermediate region 120B. In such an example, the picks per inch of proximal region 120C may be in the range of 120 PPI to 140 PPI (e.g., 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140 PPI, or any value therebetween).

[0089] The picks per inch of distal region 120A can be in the range of approximately 65 PPI to 90 PPI (e.g., 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90 PPI, or any value therebetween).

[0090] The number of picks per inch in intermediate region 120B may vary between the number of picks per inch in proximal region 120C and the number of picks per inch in distal region 120A.

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

[0092] The outer jacket 102 is shown in FIGS. 1 and 7, and a portion of the outer jacket 102 within the distal section 100A of the catheter 100 is shown in FIG. 5. The outer jacket 102 may extend to the very distal end of the catheter 100 and to the catheter hub 106 at the proximal end of the catheter 100. In one example, the outer jacket 102 may have a length in the range of about 110 cm to 135 cm (e.g., a working length of about 115 cm or about 125 cm). Generally, the flexibility or hardness (e.g., durometer) of the outer jacket 102 increases or decreases toward the distal end of the catheter 100; however, the outer jacket 102 may decrease or increase in hardness near the distal end of the catheter 100 (e.g., within 0.5 to 3 cm of the distal end), if desired.

[0093] The outer jacket 102 will be further described with respect to individual jacket segments. However, it should be understood that such discussion includes both multiple tubular segments of different properties connected together to form a tubular layer, and a single tubular structure molded or extruded as a single tube with a gradual change in material and / or thickness along its length. In this regard, the tubular segments may have an abrupt change in property (e.g., hardness) or a relatively gradual change in property along the length of the outer jacket. In the example of assembling individual segments, the segments may have cut surfaces perpendicular to the axial direction (e.g., between segments 102A and 102B) or may have cut surfaces at an angle (e.g., 45 degrees) to the axial direction of the catheter to allow for a smoother transition between materials of different durometers. In the example of segments with beveled cut surfaces, length measurements may be taken between the respective tips of the segments, only between the portions without beveled cut surfaces, or from one beveled cut surface tip to a position just prior to the opposite beveled cut surface tip (as shown in FIG. 5). Segments are also described in terms of hardness and durometer, although it should be understood that sections of increased and decreased durometer have similarly increased or decreased flexibility. All durometer values ​​herein are Shore A hardness values.

[0094] The proximal segment 102M of the outer jacket 102 may generally have the least flexibility in the outer jacket 102 to maximize support and stiffness. In one example, the proximal segment 102M may be constructed of a relatively stiff material such as Pebax or nylon (Grilamid L25). The proximal segment 102M may have a wall thickness in the range of 0.004 to 0.007 inches (e.g., 0.004, 0.005, 0.006, 0.007 inches, and values ​​therebetween). The proximal segment 102M may have a length in the range of about 80 cm to about 100 cm (e.g., 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100 cm, and values ​​therebetween). The hardness can range from a durometer value of 50A to 120A.

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

[0096] In one example, the distal segments 102 generally each have an increased flexibility and / or a decreased durometer compared to the immediately proximal segment. In another example, the distal segments 102 generally each have an increased flexibility and / or a decreased durometer compared to the immediately proximal segment, except for one or more segments at the most distal end of the outer jacket 102.

[0097] In one example, only distal segment 102A has a decreased flexibility or increased durometer compared to distal segment 102B. Distal segment 102A may have a length 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 any length therebetween). Distal segment 102A may have a durometer value 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, Distal segment 102B may be constructed of a TPU or similar material having a durometer value of at least one unit lower than that of distal segment 102A, but as much as 20-30 units lower. For example, distal segment 102A may have a hardness of 27A to 32A (e.g., 27A, 28A, 29A, 30A, 31A, or 32A), and distal segment 102B may have a hardness of 10A to 14A (e.g., 10A, 11A, 12A, 13A, or 14A).

[0098] In one example, only distal segment 102A and distal segment 102B have a reduced flexibility or increased durometer compared to distal segment 102B. Distal segment 102A and distal segment 102B may have lengths ranging from 0.5 cm to 3.0 cm (e.g., 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 cm, or any value therebetween). Distal segment 102C may be constructed of TPU or a similar material having a durometer at least one unit lower than distal segment 102B, but as much as 20 to 30 units lower. Distal segment 102A may be the same as distal segment 102B or at least one unit lower than distal segment 102B. For example, distal segment 102A may have a durometer value in the range of 27A to 32A (e.g., 27A, 28A, 29A, 30A, 31A, 32A, or values ​​therebetween), distal segment 102B may have a durometer value that is the same as segment 102A or a lower value within the same range, while distal segment 102C may have a durometer value in the range of approximately 10A to 14A (e.g., 10A, 11A, 12A, 13A, 14A, or values ​​therebetween). This pattern may be further extended so that any of the plurality of distal segments 102A, 102B, 102C, 102D, and / or 102E may have a durometer value within the range of 27A to 32A (e.g., 27A, 28A, 29A, 30A, 31A, 32A, or any value therebetween) with a gradually increasing durometer value and decreasing flexibility in the proximal direction, so long as each section has a durometer value that is the same as or higher than the proximally adjacent section.

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

[0100] It should be noted that sections 102L-102F may also generally have a progressively decreasing stiffness (increasing flexibility) in a distal direction, although specific exemplary Shore values ​​are not necessarily provided herein. For example, these Shore values ​​may be in the range of approximately 20D-100D Shore values.

[0101] Some example durometer progressions are provided below in Table 1. While an increase in durometer in the distal portion (e.g., 102A) is one aspect of outer jacket 102, another aspect, as shown below, is an increase in durometer progression in the proximal section, which can result in a dramatic increase in proximal stiffness. This dramatic increase in proximal stiffness can be useful in larger catheters, as described elsewhere herein, allowing them to be pushed without kinking or collapsing, allowing the distal portion to be threaded through tortuous blood vessels.

[0102] [Table 1]

[0103] Another approach to characterizing the outer jacket 102 in the distal section 100A of the catheter 100 is to say that the outer jacket 102 may have a particular hardness / durometer or average hardness / durometer at a particular length from the distal end of the catheter 100. Example lengths and durometers are provided in Table 2 below. The following lengths are referred to as the most distal section (0-0.5 cm, or 0-0.05 cm), the penultimate section (0.5-3.5 cm, or 0.05-3.5 cm), and similarly for the remaining segments. The use of a relatively short most distal section (e.g., 0-0.5 cm in length) can be useful for passing through the aortic arch.

[0104] [Table 2]

[0105] [Table 2B]

[0106] [Table 2C]

[0107] In the examples shown in Tables 2B and 2C above, the distal-most section, having a Shore 30A durometer, is 0–0.05 cm in length. Alternatively, this section may range from 0–0.01 cm in length to 0–0.1 cm in length (or up to 0.5 cm, as shown in Table 2). This may be advantageous or beneficial for the operator when advancing into the aortic arch (shown in Figure 14), particularly a type III aortic arch. Type III aortic arches are relatively rare in the general population. Estimates vary, but they are thought to occur in less than 25% of the adult population. However, type III aortic arches are more common among elderly patients and those with risk factors for stroke, aneurysms, and other medical or acute illnesses that may require endovascular intervention. Again, estimates vary, but the prevalence of type III aortic arches in patients undergoing neuroendovascular procedures may be as high as 50% or more. The type III aortic arch is particularly difficult to navigate during endovascular procedures (e.g., when accessing the right common carotid artery (RCA) or left common carotid artery (LCA)) due to the double hairpin bend between the descending aorta, the aortic arch, and the brachiocephalic trunk. The catheters described herein, particularly those with high durometer values ​​in their distal-most sections (e.g., those described in Tables 2, 2B, and 2C), can be advantageous or beneficial to the operator and / or patient by providing a sufficiently stiff distal tip that does not collapse or "fold" when contacting the vessel wall during navigation through tortuous anatomy (e.g., a type III aortic arch). However, the distal section of the catheter immediately proximal to the distal tip (i.e., the penultimate section) can be sufficiently flexible to provide sufficient flexibility near the distal end of the catheter. This allows for improved navigation and tracking in difficult and / or tortuous anatomy such as at least a Type II or Type III aortic arch.

[0108] Another approach to characterizing the outer jacket 102 in the distal portion 100A of the catheter 100 is that the hardness or durometer of the outer jacket 102 may increase by approximately a factor of two, three, or so from the proximal section to its distally adjacent distal section (e.g., from distal section 102B to distal section 102A). For example, the durometer between distal section 102B and distal section 102A may increase by approximately 100 (i.e., a factor of two), 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300 (i.e., a factor of three), 310, 320, 330, 340, 350 percent, or any value therebetween. In such cases,

[0109] Another approach to generally characterizing the distal portion 100A of the catheter 100 is that the stiffness may increase by approximately a factor of two, three, etc. from a proximal point of the distal portion 100A to a distal point of the distal portion 100A. For example, a point within 0-2 cm from the distal end may increase by approximately a factor of two, three, etc., compared to a point within 2 cm-4 cm from the distal end. For example, the stiffness between two points may increase by approximately 100 (i.e., 2x), 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300 (i.e., 3x), 310, 320, 330, 340, 350 percent, or any percentage value therebetween.

[0110] Another approach to overall catheter flexibility may include flexibility values ​​at various locations from the distal end of catheter 100. Example values ​​are shown below in Tables 3 and 4. These values ​​may be exemplary values ​​that include a range of 10% above or below each value, or may be considered as an average value for a range of lengths that overlap with the specified length value (e.g., equal length overlap proximally and distally).

[0111] [Table 3]

[0112] [Table 4]

[0113] The following examples illustrate example layer combinations for the catheters described above. While specific values ​​(e.g., length, PPI, coil width, durometer, etc.) may not be specified below, reference is made to the example values ​​set forth in the preceding description for each of these layers. The distal 0.5 cm position may have a stiffness in the range of 4 gf / mm to 20 gf / mm. The distal 2 cm position may have a stiffness in the range of 2 gf / mm to 18 gf / mm.

[0114] In one example, catheter 100 comprises a coil layer 118 that increases in flexibility toward its distal end, a braided layer 120 that increases in flexibility toward its distal end, and an outer jacket layer 102 that increases in flexibility toward its distal end and then decreases in flexibility toward its distal end (e.g., decreasing over a length of 0.5 to 3 cm from its distal end).

[0115] In one example, catheter 100 comprises a coil layer 118 that increases in flexibility toward its distal end and then decreases in flexibility toward its distal end (e.g., decreasing between 0.5 and 3 cm from its distal end), a braided layer 120 that increases in flexibility toward its distal end, and an outer jacket layer 102 that increases in flexibility toward its distal end.

[0116] In one example, the catheter 100 comprises a coil layer 118 that increases in flexibility toward its distal end, a braided layer 120 that increases in flexibility toward its distal end but then decreases in flexibility toward its distal end (e.g., decreasing over a length of 0.5 to 3 cm from its distal end), and an outer jacket layer 102 that increases in flexibility toward its distal end.

[0117] In one example, catheter 100 comprises a coil layer 118 that increases in flexibility toward its distal end and then decreases in flexibility toward its distal end (e.g., decreases between 0.5 and 3 cm from its distal end), a braided layer 120 that increases in flexibility toward its distal end and then decreases in flexibility toward its distal end (e.g., decreases between 0.5 and 3 cm from its distal end), and an outer jacket layer 102 that increases in flexibility toward its distal end and then decreases in flexibility toward its distal end (e.g., decreases between 0.5 and 3 cm from its distal end).

[0118] In another example, the proximal portion of the catheter 100 may have catheter flexibility characteristics with a relatively high proximal stiffness and a relatively low distal stiffness (e.g., between 2 and 40 cm from the distal tip of the catheter, as shown in Figures 8 and 9), regardless of the stiffness of the most distal tip of the catheter 100. This combination of high proximal stiffness and low distal stiffness can be particularly useful for larger catheters to steer their progression while preventing kinking or collapse.

[0119] For example, between the distal tip and approximately 7-12 cm proximal, catheter 100 may have an average stiffness of approximately 5 gf / mm. Between approximately 7-12 cm proximal from the distal tip and approximately 40-100 cm proximal from the distal tip, the average stiffness may be approximately 450-550 gf / mm. In other words, the average stiffness between approximately 7-12 cm proximal from the distal tip and approximately 40-100 cm proximal from the distal tip is approximately 7,000-11,000 percent higher, or more specifically, 9,000-10,000 percent higher (e.g., 7,000, 7,500, 8,000, 8,500, 9,000, 9,500, 10,000, 10,500, 11,000 percent, and values ​​therebetween or thereabouts).

[0120] In other words, between the distal tip of the catheter and about 10 cm proximal to the distal tip, the average stiffness value is about 2-10 gf / mm, between about 10 cm and about 13 cm from the distal tip, the average stiffness value increases proximally to about 9 gf / mm to 39 gf / mm, between about 13 cm and about 30 cm from the distal tip, the average stiffness value increases proximally to about 29 gf / mm to 480 gf / mm, and between about 30 cm and about 40 cm from the distal tip, the average stiffness value increases proximally to about 480 gf / mm to 495 gf / mm. These example values, and the more specific example values ​​in Table 5, may vary by about 10 percent.

[0121] [Table 5]

[0122] As best shown in Figures 8-13, an example catheter may have varying stiffness characteristics along its length. The catheter may have at least a distal section, a penultimate distal section, a penultimate proximal section, and a proximal section. The stiffness of the distal section may be greater than the stiffness of the penultimate distal section. The stiffness of the penultimate proximal section may be greater than the stiffness of the penultimate distal section, with the stiffness increasing along the length of the penultimate proximal section. The stiffness of the proximal section may be substantially uniform.

[0123] By way of example, the most distal section of the catheter may have a stiffness greater than the stiffness of the next-to-most distal section of the catheter proximally adjacent to the most distal section. The next-to-most distal section may have a substantially uniform, lower stiffness before transitioning to the next-to-most proximal section having a varying stiffness. The proximal section of the catheter may have a substantially uniform stiffness.

[0124] As an example, a catheter may include an elongate catheter body and an outer jacket disposed along the elongate catheter body and having a distal region. The distal region may have a gradient hardness that decreases distally along the longitudinal axis from a distal end of the catheter body toward the distal end to an extreme distal end of the catheter body. The hardness of the outer jacket at the extreme distal end of the catheter body may be between 20A and 50A Shore. The hardness of the outer jacket at a portion of the outer jacket proximal to the extreme distal end of the catheter body may be between 10A and 20A Shore. The distal region having a gradient hardness that decreases toward the distal end of the catheter body may include a first outer jacket segment having a first hardness joined to an interface region with a second outer jacket segment having a second hardness. The interface region may have a smooth transition from the first hardness to the second hardness. The interface region may have a length of at least 0.5 cm, or between 0.1 cm and 1.0 cm. The interface region may comprise a joint (e.g., a butt joint or a scarf joint) between two adjacent regions having different hardnesses or durometers. The joint may be an angled joint (e.g., a scarf joint), a straight joint (e.g., a butt joint), or various other types of joint. Advantages of an angled or scarf joint may include at least that the transition between the stiffnesses or hardnesses of the adjacent bonded regions may be smoother than another type of joint (e.g., a butt joint) that has a sharper transition zone between the respective regions.

[0125] As an example, a catheter may include an elongate catheter body having a distal section, a proximal section, and an intermediate section therebetween. The distal section may have a first stiffness less than 50 gf / mm, the intermediate section may have a second stiffness, and the proximal section may have a third stiffness greater than 400 gf / mm. The second stiffness may include a range of stiffness varying between the first stiffness and the third stiffness. The intermediate section may extend between 7 and 13 cm from the distal tip of the elongate catheter body and between 25 and 35 cm from the distal tip of the elongate catheter body. The second stiffness range of the intermediate section may increase at a substantially linear rate from distal to proximal. The entire second stiffness range of the intermediate section may increase at a rate not exceeding 60 gf / mm per cm of catheter body length (e.g., 10 to 60 gf / mm per cm) from distal to proximal.

[0126] As an example, a catheter may include an elongate catheter body including a proximal section, an intermediate section, and a distal section. The intermediate section may be between the proximal and distal sections. The intermediate section may have an increasing stiffness between a first stiffness and a second stiffness. The first stiffness may be located at the distal end of the intermediate section and the second stiffness may be located at the proximal end of the intermediate section.

[0127] The locations of the proximal and distal ends of the intermediate section may vary in various examples. The distal end of the intermediate section may be located between about 0.01 cm from the distal tip of the distal section and 15 cm from the distal tip of the distal section. The distal end of the intermediate section may be located between about 5 cm from the distal tip of the distal section and 10 cm from the distal tip of the distal section. The proximal end of the intermediate section may be located between about 20 cm from the distal tip of the distal section and 40 cm from the distal tip of the distal section. The proximal end of the intermediate section may be located between about 25 cm from the distal tip of the distal section and 35 cm from the distal tip of the distal section. The distal end of the intermediate section may be located about 10 cm from the distal tip of the distal section. The proximal end of the intermediate section may be located about 30 cm from the distal tip of the distal section.

[0128] The respective first and second stiffnesses may have different values ​​in various embodiments. The first stiffness may be less than 50 gf / mm. The second stiffness may be greater than 400 gf / mm. The first stiffness may be between about 1 gf / mm and 100 gf / mm. The second stiffness may be between about 300 gf / mm and 600 gf / mm. Thus, the second stiffness may be at least five times the first stiffness, or in other examples, at least twice the first stiffness. The rise 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] Figures 8 and 10 show examples of stiffness profiles relative to the length of the catheter. As shown, the distal section, including the distal tip, may have a first stiffness, and the penultimate distal section may have a second stiffness that is lower than the first stiffness of the distal section. While Figures 8 and 10 show specific stiffness values ​​in gf / mm for illustrative purposes, it should be understood that the listed values ​​are not intended to limit the scope of the invention. Furthermore, the respective lengths of the distal section and the penultimate distal section may vary in various examples.

[0130] 8 and 10 , it can be seen that the second-most proximal section may be located proximally adjacent to the second-most distal section. The second-most proximal section may have a gradually increasing stiffness along the length of the second-most proximal section. The increase in stiffness may be linear or non-linear, and a segment of the length of the second-most proximal section may have a substantially uniform stiffness. The second-most proximal section may transition into the proximal section such that the stiffness is substantially uniform along the proximal section, up to and including the proximal end of the catheter.

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

[0132] The penultimate distal section may have an approximate length of about 5 cm to 10 cm, although longer or shorter lengths may be employed. The penultimate proximal section may have an approximate length of about 15 cm to 40 cm, although longer or shorter lengths may be employed. The proximal section may have an approximate length of about 70 cm to 130 cm, although longer or shorter lengths may be employed. The entire catheter, including the distal section, penultimate distal section, penultimate proximal section, and proximal section, may have a length of about 100 cm to 200 cm, although longer or shorter lengths may be employed.

[0133] 11-13 illustrate by showing example ranges of stiffness values ​​that the stiffness of each section of the catheter should not be construed as limited to the particular example values ​​shown in the figures, although it should be understood that in some instances the stiffness of one or more portions may be outside of the example ranges shown in FIGS.

[0134] Figure 11 illustrates a range of stiffness along the second-most proximal section of the catheter, which may have increasing stiffness along this range. Figure 12 illustrates a range of stiffness along the second-most distal section, showing that at least one segment of the second-most distal section may have a substantially uniform stiffness. Figure 13 illustrates a range of stiffness along a proximal segment of the second-most proximal section and a distal segment of the proximal section, showing how the increasing stiffness segment transitions to a uniform stiffness segment.

[0135] 11-13 illustrate that the stiffness ranges may be considered to be divided into "high dispersion," "medium dispersion," and "low dispersion." These descriptions are for illustrative purposes only and should not be construed as limiting the scope of the invention in any way. The adoption of "high dispersion" in one section (e.g., the penultimate distal section) should not be construed as requiring the adoption of the same "high dispersion" in another section (e.g., the penultimate proximal section). Thus, as an example, the penultimate distal section may have a stiffness within the high dispersion range, while the penultimate proximal section may have a stiffness within the medium dispersion range. In certain instances, any of the dispersion ranges may be combined.

[0136] The manner in which the stiffness varies along the length of the catheter may vary in various examples. As previously mentioned, examples of methods or devices for varying stiffness may include, but are not limited to, the use of an outer jacket, a coiled wire, a braided mesh tubular layer, an inner liner, and / or radiopaque markers. In one example, all or a portion of the length of the catheter, including the penultimate distal section and the distal section, may be integrally formed as a single piece and therefore continuous.

[0137] Preliminary Claims

[0138] Item 1. A catheter comprising: an elongate catheter body having an outer jacket; a first outer jacket segment disposed within a distal portion of the elongate catheter body and having a first stiffness; and a second outer jacket segment disposed proximally adjacent to the first outer jacket segment and having a second stiffness lower than that of the first outer jacket segment.

[0139] 2. The catheter of claim 1, further comprising a third outer jacket segment disposed proximally adjacent to the second outer jacket segment, the third outer jacket segment having a third stiffness lower than that of the second outer jacket segment.

[0140] Item 3. The catheter of item 2, further comprising a fourth outer jacket segment disposed proximally adjacent to the third outer jacket segment, the fourth outer jacket segment having a fourth stiffness lower than that of the third outer jacket segment.

[0141] 4. The catheter of claim 3, wherein the first outer jacket segment has a durometer value within a range of 20 to 40 Shore A.

[0142] Clause 5. The catheter of clause 4, wherein the second outer jacket segment has a durometer value within the range of 7 to 18 Shore A.

[0143] Clause 6. The catheter of clause 5, wherein the third outer jacket segment has a durometer value within the range of 14 to 25 Shore A.

[0144] Clause 7. The catheter of clause 6, wherein the fourth outer jacket segment has a durometer value within the range of 20 to 40 Shore A.

[0145] Clause 8. The catheter of clause 1, wherein the distal section of the elongate catheter body further comprises a coil having a relatively large pitch near a distal end of the distal section and a relatively small pitch near a proximal end of the distal section.

[0146] Clause 9. The catheter of clause 8, wherein the relatively large pitch of the coil is in the range of 0.006 inches to 0.01 inches.

[0147] Clause 10. The catheter of clause 9, wherein the relatively small pitch of the coil is in the range of 0.003 inches to 0.0055 inches.

[0148] Clause 11. The catheter of clause 8, further comprising a braided nitinol tube disposed around the coil, the braided nitinol tube having a relatively small PPI near its distal end and a relatively large PPI near its proximal end.

[0149] Item 12. The catheter according to item 11, wherein the relatively small PPI is in the range of 55 PPI to 100 PPI.

[0150] Clause 13: A catheter comprising: an elongate catheter body; and an outer jacket disposed along the elongate catheter body, the distal region of the outer jacket comprising a plurality of jacket segments that decrease in hardness and then increase in hardness toward the distal end of the elongate catheter body.

[0151] Clause 14. The catheter of clause 13, wherein a distal-most jacket segment of the plurality of jacket segments has a higher hardness than a proximally adjacent jacket segment of the plurality of jacket segments.

[0152] Clause 15. The catheter of clause 13, wherein the distal region of the elongate catheter body further comprises a coil having a relatively large pitch near its distal end and a relatively small pitch near its proximal end.

[0153] Clause 16. The catheter of clause 15, further comprising a braided nitinol tube disposed around the coil, the braided nitinol tube having a relatively small PPI near its distal end and a relatively large PPI near its proximal end.

[0154] Clause 17. The catheter of clause 16, wherein the plurality of outer jacket segments are constructed of a polyurethane elastomer.

[0155] Clause 18. The catheter of clause 17, further comprising an inner liner forming an inner passageway through the catheter, the inner liner comprising a proximal PTFE tube and a distal polyolefin elastomer tube, the proximal PTFE tube and the distal polyolefin elastomer tube being connected via a tube bonded around the distal end of the proximal PTFE tube and the proximal end of the distal polyolefin elastomer tube.

[0156] Clause 19. The catheter of clause 18, wherein the distal polyolefin elastomer tube has a length within the range of 11 cm to 15 cm, and the proximal PTFE tube has a length within the range of 90 cm to 120 cm.

[0157] Clause 20. A catheter comprising a catheter body and outer jacket means having a decreasing hardness followed by an increasing hardness towards the distal end of said catheter body.

[0158] Clause 21: A catheter comprising: an elongate catheter body having an outer jacket; a first outer jacket segment disposed within a distal portion of the elongate catheter body and having a first hardness; and a second outer jacket segment disposed proximally adjacent the first outer jacket segment and having a second hardness lower than that of the first outer jacket segment.

[0159] Clause 22. The catheter of clause 21, wherein the first outer jacket segment has a durometer within the range of 20 to 40 Shore A.

[0160] Clause 23. The catheter of clause 22, wherein the first outer jacket segment has a durometer 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] Clause 24: The catheter of any one of clauses 21 to 23, wherein the second outer jacket segment has a durometer value of 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18 Shore A hardness.

[0162] Item 25: The catheter according to any one of items 21 to 24, further comprising a third outer jacket segment disposed adjacent to the second outer jacket segment on the proximal side and having a third hardness higher than that of the second outer jacket segment.

[0163] Clause 26: The catheter of any one of clauses 21 to 25, wherein the third outer jacket segment has a durometer value of 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25.

[0164] Item 27: The catheter according to any one of items 21 to 26, further comprising a fourth outer jacket segment disposed adjacent to the third outer jacket segment on the proximal side and having a fourth stiffness higher than that of the third outer jacket segment.

[0165] Clause 28: The catheter of any of clauses 21-27, wherein the fourth outer jacket segment has a durometer 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] Item 29: The catheter according to any one of items 21 to 28, further comprising a fifth outer jacket segment disposed adjacent to the fourth outer jacket segment on the proximal side and having a fifth hardness higher than that of the fourth outer jacket segment.

[0167] Clause 30. The catheter of any of clauses 21-29, wherein the fifth outer jacket segment has a durometer 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] Item 31: The catheter according to any one of items 21 to 30, further comprising a sixth outer jacket segment disposed adjacent to the fifth outer jacket segment on the proximal side and having a sixth hardness higher than that of the fifth outer jacket segment.

[0169] Clause 32: The catheter of any of clauses 21-31, wherein the sixth outer jacket segment has a durometer 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] Item 33: The catheter according to any one of items 21 to 32, further comprising a seventh outer jacket segment disposed proximally adjacent to the sixth outer jacket segment and having a seventh hardness higher than that of the sixth outer jacket segment.

[0171] Clause 34: The catheter of any of clauses 21-33, wherein the seventh outer jacket segment has a durometer 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] Clause 35: The catheter according to any one of clauses 21 to 34, wherein the elongated catheter body further comprises a coil having a relatively large pitch near the distal end and a relatively small pitch near the proximal end.

[0173] Clause 36: The catheter according to any one of clauses 21 to 35, wherein the relatively large pitch of the coil is within a range of 0.006 inches to 0.01 inches.

[0174] Clause 37: The catheter according to any one of clauses 21 to 36, wherein the relatively large pitch of the coil is 0.006, 0.007, 0.008, 0.009, or 0.01 inches.

[0175] Clause 38: The catheter according to any one of clauses 21 to 37, wherein the relatively small pitch of the coil is within a range of 0.003 inches to 0.0055 inches.

[0176] Item 39: The catheter according to any one of items 21 to 38, wherein the coil further has an intermediate pitch between the relatively small pitch and the relatively large pitch, the intermediate pitch being within a range of 0.003 to 0.008 inches.

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

[0178] Item 41: The catheter according to any one of items 21 to 40, further comprising a braided nitinol tube disposed around the coil, the braided nitinol tube having a relatively small PPI near the distal end and a relatively large PPI near the proximal end.

[0179] Clause 42: The catheter according to any one of clauses 21 to 41, wherein the relatively small PPI is within a range of 55 PPI to 100 PPI, and the relatively large PPI is within a range of 120 to 145 PPI.

[0180] Clause 43: The catheter of any one of clauses 21 to 42, wherein the relatively small PPI is 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, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100 PPI.

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

[0182] Clause 45: The catheter according to any one of clauses 21 to 44, wherein any one of the outer jacket segments is made of polyurethane elastomer.

[0183] Clause 46: The catheter according to any one of clauses 21 to 45, further comprising an inner liner forming an inner passageway through the catheter, the inner liner comprising a proximal PTFE tube and a distal polyolefin elastomer tube, the proximal PTFE tube and the distal polyolefin elastomer tube being connected via a tube joined around the distal end of the proximal PTFE tube and the proximal end of the distal polyolefin elastomer tube.

[0184] Item 47: The catheter according to any one of items 21 to 46, wherein the distal polyolefin elastomer tube has a length within the range of 11 cm to 15 cm, and the proximal PTFE tube has a length within the range of 90 cm to 120 cm.

[0185] Clause 48. A catheter comprising: an elongate catheter body having an inner liner forming a passageway therethrough, the inner liner having a proximal portion formed of a first material and a distal portion formed of a second material; and a coil disposed about the distal portion of the inner liner, the coil having a relatively large pitch near the distal end and a relatively small pitch near the proximal end.

[0186] Clause 49. The catheter of clause 48, wherein the transition from the relatively large pitch to the relatively small pitch occurs across an interface between the first and second materials of the inner liner.

[0187] Clause 50: The catheter according to any one of clauses 48 to 49, wherein the relatively large pitch of the coil is within a range of 0.006 inches to 0.01 inches.

[0188] Clause 51: The catheter according to any one of clauses 48 to 50, wherein the relatively large pitch of the coil is 0.006, 0.007, 0.008, 0.009, or 0.01 inches.

[0189] Clause 52: The catheter according to any one of clauses 48 to 51, wherein the relatively small pitch of the coil is within the range of 0.003 inches to 0.0055 inches.

[0190] Item 53: The catheter according to any one of items 48 to 52, wherein the coil further has an intermediate pitch between the relatively small pitch and the relatively large pitch, the intermediate pitch being within a range of 0.003 to 0.008 inches.

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

[0192] Item 55: The catheter according to any one of items 48 to 54, further comprising a braided nitinol tube disposed around the coil, the braided nitinol tube having a relatively small PPI near the distal end and a relatively large PPI near the proximal end.

[0193] Clause 56: The catheter according to any one of clauses 48 to 55, wherein the relatively small PPI is within a range of 55 PPI to 100 PPI, and the relatively large PPI is within a range of 120 PPI to 145 PPI.

[0194] Clause 57: The catheter of any one of clauses 48 to 56, wherein the relatively small PPI is 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, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100 PPI.

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

[0196] Clause 59: A catheter comprising: an elongate catheter body having an outer jacket; a first outer jacket segment disposed within a distal portion of the elongate catheter body, the first outer jacket segment having a first durometer; and a second outer jacket segment disposed proximally adjacent the first outer jacket segment, the second outer jacket segment having a second durometer that is lower than the first outer jacket segment, wherein the durometer of the first outer jacket segment 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 percent higher than the durometer of the second outer jacket segment.

[0197] Clause 60: A catheter comprising an elongate catheter body having a plurality of layers forming a catheter wall, the catheter wall forming a lumen between a proximal end and a distal end of the catheter, the distal portion of the catheter having increasing flexibility toward the distal end of the catheter and then decreasing flexibility to the distal end of the catheter.

[0198] Clause 61. A catheter comprising: an elongate catheter body; and an outer jacket disposed along the elongate catheter body and having a distal region, the distal region having a decreasing hardness toward the distal end of the catheter body followed by an increasing hardness to the distal end of the catheter body.

[0199] Clause 62: The catheter of clause 61, wherein the distal region increases in hardness to a hardness within a range of Shore 20A to 40A over a length extending between about 0 cm and about 0.5 cm from the distal end of the catheter body.

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

[0201] Clause 63: The catheter of clause 62, wherein the distal region tapers to a hardness within the range of 12 to 18 Shore A for at least a length extending between about 0.5 cm and about 15 cm from the distal end of the catheter body.

[0202] Clause 64. A catheter comprising an elongate catheter body having a distal region including a distal section and a proximal section, wherein the distal section has 100 (i.e., 2 times), 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300 (i.e., 3 times), 310, 320, 330, 340, or 350 percent greater stiffness than the proximal section.

[0203] Clause 65: A catheter comprising an elongate catheter body having a distal region and a proximal region, the proximal region having a stiffness that is 7000, 7500, 8000, 8500, 9000, 9500, 10000, 10500, or 11000 percent greater than the distal region, or a percentage value within a range inclusive of said percentage value.

[0204] Item 66. The catheter of item 65, wherein the distal region is between approximately 0 cm proximal and 7-12 cm proximal from the distal tip, and the proximal region is between 7-12 cm proximal from the distal tip and 40-100 cm proximal from the distal tip.

[0205] Clause 67: A catheter comprising an elongated catheter body having a distal end, wherein the average stiffness value is approximately 2 to 10 gf / mm between the distal end of the catheter and a point approximately 10 cm proximal to the distal end of the catheter, the average stiffness value increases from approximately 9 gf / mm to 39 gf / mm between approximately 10 cm and approximately 13 cm from the distal end of the catheter toward the proximal side, the average stiffness value increases from approximately 29 gf / mm to 480 gf / mm between approximately 13 cm and approximately 30 cm from the distal end of the catheter toward the proximal side, and the average stiffness value increases from approximately 480 gf / mm to 495 gf / mm between approximately 30 cm and approximately 40 cm from the distal end of the catheter toward the proximal side.

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

[0207] Clause 69. The catheter of clause 68, further comprising a third outer jacket segment proximally abutting the second outer jacket segment and having a third stiffness greater than the second outer jacket segment.

[0208] Clause 70: The catheter according to any one of clauses 68 to 69, further comprising a fourth outer jacket segment disposed adjacent to the third outer jacket segment on the proximal side and having a fourth stiffness higher than that of the third outer jacket segment.

[0209] Clause 71: The catheter according to any one of clauses 68 to 70, wherein the first outer jacket segment has a durometer value within a range of 20 to 40 Shore A hardness.

[0210] Clause 72: The catheter according to any one of clauses 68 to 71, wherein the second outer jacket segment has a durometer value within a range of 7 to 18 Shore A hardness.

[0211] Clause 73: The catheter according to any one of clauses 68 to 72, wherein the third outer jacket segment has a durometer value within a range of 14 to 25 Shore A hardness.

[0212] Clause 74: The catheter according to any one of clauses 68 to 73, wherein the fourth outer jacket segment has a durometer value within a range of 20 to 40 Shore A hardness.

[0213] Clause 75: The catheter according to any one of clauses 68 to 74, wherein the elongated catheter body further comprises a coil having a relatively large pitch near the distal end and a relatively small pitch near the proximal end.

[0214] Clause 76: The catheter according to any one of clauses 68 to 75, wherein the relatively large pitch of the coil is within the range of 0.006 inches to 0.01 inches.

[0215] Clause 77: The catheter according to any one of clauses 68 to 76, wherein the relatively small pitch of the coil is within the range of 0.003 inches to 0.0055 inches.

[0216] Item 78: The catheter according to any one of items 68 to 77, further comprising a braided nitinol tube disposed around the coil, the braided nitinol tube having a relatively small PPI near the distal end and a relatively large PPI near the proximal end.

[0217] Clause 79: The catheter according to any one of clauses 68 to 78, wherein the relatively small PPI is within a range of 55 PPI to 100 PPI, and the relatively large PPI is within a range of 120 to 145 PPI.

[0218] Clause 80: A catheter comprising: an elongate catheter body; and an outer jacket disposed along the elongate catheter body and having a distal region, the distal region decreasing in hardness toward the distal end of the catheter body and then increasing in hardness to the distal end of the catheter body.

[0219] Clause 81: The catheter of clause 80, wherein the distal region increases in hardness to a hardness within a range of Shore 20A to 40A over a length extending between about 0 cm and about 0.5 cm from the distal end of the catheter body.

[0220] Clause 82: The catheter according to any one of clauses 80 to 81, wherein the distal region has a hardness that increases to a hardness within a range of Shore 20A to 40A over a length extending between about 0 cm and about 3 cm from the distal end of the catheter body.

[0221] Clause 83: The catheter of any one of clauses 80 to 82, wherein the distal region has a length extending from the distal end of the catheter body that is at least about 0.5 cm and about 15 cm, the hardness of which decreases to a hardness within a range of 12 to 18 Shore A.

[0222] Clause 84: A catheter according to any one of clauses 80 to 83, wherein the distal region has an increasing hardness over a length extending between about 0 cm and about 3 cm from the distal end, with the Shore A hardness increasing by a factor of two or three in the proximal direction in the distal region.

[0223] Clause 85: A catheter according to any one of clauses 80 to 84, further comprising an inner liner forming an inner passageway through the catheter, the inner liner comprising a proximal PTFE tube and a distal polyolefin elastomer tube, the proximal PTFE tube and the distal polyolefin elastomer tube being connected via a tube joined around the distal end of the proximal PTFE tube and the proximal end of the distal polyolefin elastomer tube.

[0224] Item 86: The catheter according to any one of items 80 to 85, wherein the distal polyolefin elastomer tube has a length in the range of 11 cm to 15 cm, and the proximal PTFE tube has a length in the range of 90 cm to 120 cm.

[0225] Clause 87. A catheter comprising: a catheter body means; and outer jacket means having a decreasing hardness followed by an increasing hardness toward the distal end of said catheter body means.

[0226] Clause 88: A catheter comprising an elongate catheter body, a penultimate distal section having a first stiffness, and a distal-most section having a second stiffness, the second stiffness being greater than the first stiffness.

[0227] Clause 89. The catheter of clause 88, wherein the stiffness of the catheter increases from a first stiffness about 5 cm from the distal tip of the most distal section to a second stiffness about 30 cm from the distal tip of the most distal section.

[0228] Item 90: The catheter according to items 88 and 89, wherein the first stiffness is less than 50 gf / mm.

[0229] Item 91: The catheter according to any one of items 88 to 90, wherein the second stiffness is higher than 400 gf / mm.

[0230] Item 92: The catheter according to any one of items 88 to 91, wherein the increase in stiffness is substantially linear.

[0231] Item 93: The catheter according to any one of items 88 to 92, wherein the stiffness at 30 cm from the distal tip portion is 100 gf / mm to 400 gf / mm.

[0232] Item 94: The catheter according to any one of items 88 to 93, wherein the stiffness at 40 cm from the distal tip portion is 100 gf / mm to 400 gf / mm.

[0233] Item 95: The catheter according to any one of items 88 to 94, wherein the stiffness at 30 cm from the distal tip portion is 150 gf / mm to 350 gf / mm.

[0234] Item 96: The catheter according to any one of items 88 to 95, wherein the stiffness at 40 cm from the distal tip portion is 150 gf / mm to 350 gf / mm.

[0235] Item 97: The catheter according to any one of items 88 to 96, wherein the stiffness at a position 40 cm to 90 cm from the distal tip portion is 400 gf / mm to 600 gf / mm.

[0236] Item 98: The catheter according to any one of items 88 to 97, wherein the stiffness at a position 40 cm to 120 cm from the distal tip portion is 400 gf / mm to 600 gf / mm.

[0237] Clause 99: The catheter of any one of clauses 88 to 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 second-most distal portion and a second stiffness along the most distal portion.

[0238] Clause 100: The catheter according to any one of clauses 88 to 99, wherein the braided mesh tubular layer is disposed within the wall of the catheter.

[0239] Clause 101: The catheter according to any one of clauses 88 to 100, wherein the braided mesh tubular layer is disposed between the outer jacket and the inner coil.

[0240] Clause 102: The catheter according to any one of clauses 88 to 101, wherein the braided mesh tubular layer is disposed below the inner coil.

[0241] Clause 103: The catheter according to any one of clauses 88 to 102, wherein the number of picks per inch of the braided mesh tubular layer along the first section having the first stiffness is greater than the number of picks per inch of the braided mesh tubular layer along the second section having the second stiffness.

[0242] Clause 104: A catheter according to any one of clauses 88 to 103, wherein the diameter of the wire forming the braided mesh tubular layer is larger in the second portion having the second stiffness than in the first portion having the first stiffness.

[0243] Clause 105: The catheter of any one of clauses 88 to 98, further comprising an inner liner extending through at least a portion of the elongate catheter body, the inner liner having the first stiffness along the second-most distal portion and the second stiffness along the most distal portion.

[0244] Clause 106. The catheter of clause 105, wherein the inner liner comprises a first segment along the second-most distal portion and a second segment along the most distal portion, the first segment being made of a first material having a first hardness and the second segment being made of a second material having a second hardness.

[0245] Item 107: The catheter according to any one of items 105 and 106, wherein the first hardness is lower than the second hardness.

[0246] Clause 108: A catheter according to any one of clauses 105 to 107, wherein the first segment is made of a first material having a first flexibility, and the second segment is made of a second material having a second flexibility.

[0247] Clause 109: The catheter according to any one of clauses 105 to 108, wherein the first flexibility is higher than the second flexibility.

[0248] Item 110: The catheter according to any one of items 105 to 109, wherein the first material is made of PTFE, and the second material is made of polyolefin elastomer.

[0249] Item 111: The catheter according to any one of items 105 to 110, wherein the first segment and the second segment are integrally formed as a single unit.

[0250] Clause 112: A catheter comprising: an elongate catheter body; and an outer jacket disposed along the elongate catheter body, the outer jacket having a distal region, the distal region having a gradient hardness in a distal direction along a longitudinal axis, decreasing in hardness toward a distal end of the catheter body and then increasing in hardness to a most distal end of the catheter body.

[0251] Item 113: The catheter according to Item 112, wherein the hardness of the outer jacket at the distal end of the catheter body is 20A to 50A Shore hardness.

[0252] Clause 114: The catheter according to any one of clauses 112 and 113, wherein the hardness of the outer jacket in a portion of the outer jacket proximal to the most distal end of the catheter body is 10A to 20A in Shore hardness.

[0253] Clause 115: The catheter according to any one of clauses 112 to 114, wherein the distal region having a gradient hardness that decreases toward the distal end of the catheter body comprises a first outer jacket segment having a first hardness, the first outer jacket segment being bonded to a second outer jacket segment having a second hardness at an interface region.

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

[0255] Clause 117: The catheter of any one of clauses 112 to 116, wherein the interface region is at least 0.5 cm in length.

[0256] Clause 118: A catheter comprising an elongate catheter body, a proximal section, an intermediate section, and a distal section, the intermediate section being between the proximal section and the distal section, and the stiffness of the intermediate section increasing between a first stiffness and a second stiffness.

[0257] Clause 119. The catheter of clause 118, wherein the first stiffness is at a distal end of the intermediate section and the second stiffness is at a proximal end of the intermediate section.

[0258] Clause 120: The catheter according to any one of clauses 118 to 119, wherein the distal end of the intermediate section is positioned between approximately 0.01 cm from the distal tip of the distal section and 15 cm from the distal tip of the distal section.

[0259] Clause 121: The catheter according to any one of clauses 118 to 120, wherein the distal end of the intermediate section is positioned between approximately 5 cm from the distal tip of the distal section and 10 cm from the distal tip of the distal section.

[0260] Clause 122: The catheter according to any one of clauses 118 to 121, wherein the proximal end of the intermediate section is positioned between approximately 20 cm from the distal tip of the distal section and approximately 40 cm from the distal tip of the distal section.

[0261] Clause 123: The catheter according to any one of clauses 118 to 122, wherein the proximal end of the intermediate section is positioned between approximately 25 cm from the distal tip of the distal section and approximately 35 cm from the distal tip of the distal section.

[0262] Clause 124: The catheter according to any one of clauses 118 to 123, wherein the distal end of the intermediate section is positioned approximately 10 cm from the distal tip of the distal section.

[0263] Clause 125: The catheter according to any one of clauses 118 to 124, wherein the proximal end of the intermediate section is positioned approximately 30 cm from the distal tip of the distal section.

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

[0265] Item 127: The catheter according to any one of items 118 to 126, wherein the second stiffness is higher than 400 gf / mm.

[0266] Item 128: The catheter according to any one of items 118 to 127, wherein the first stiffness is approximately 1 gf / mm to 100 gf / mm.

[0267] Item 129: The catheter according to any one of items 118 to 128, wherein the second stiffness is approximately 300 gf / mm to 600 gf / mm.

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

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

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

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

[0272] Item 134: The catheter according to any one of items 118 to 133, wherein the second stiffness is about 500 gf / mm.

[0273] Item 135: The catheter according to any one of items 118 to 134, wherein the first stiffness is about 2 gf / mm to 10 gf / mm.

[0274] While the present invention has been described with respect to particular embodiments and applications, those skilled in the art will be able to generate further embodiments and modifications in light of this disclosure without departing from the spirit or beyond the scope of the invention as claimed. Accordingly, it should be understood that the drawings and descriptions herein are provided by way of example to facilitate understanding of the invention and should not be construed as limiting the scope of the invention.

Claims

1. an elongated catheter body; a second-most distal portion having a first stiffness; a distal portion having a second stiffness, the second stiffness being greater than the first stiffness; A catheter comprising:

2. The catheter of claim 1 , wherein the distal portion comprises a length of between 0.01 cm and 5 cm.

3. The catheter of claim 2 , wherein the distal portion comprises a length of between 0.01 cm and 0.2 cm.

4. 10. The catheter of claim 1, wherein the stiffness of the elongate catheter body increases from a relatively low stiffness at a first point approximately 10 cm from the distal tip of the distal section to a relatively high stiffness at a second point approximately 30 cm from the distal tip of the distal section.

5. The catheter of claim 4 , wherein the relatively low stiffness is less than 50 gf / mm.

6. The catheter of claim 5 , wherein the relatively high stiffness is greater than 400 gf / mm.

7. The catheter of claim 4 , wherein the relatively high stiffness is at least five times the relatively low stiffness.

8. The catheter of claim 4 , wherein the rise between the relatively low stiffness and the relatively high stiffness is substantially linear.

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

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

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

12. 2. The catheter of claim 1, wherein the stiffness of the segment between 30 cm and 120 cm proximal from the distal tip of the distal section is 400 gf / mm to 600 gf / mm.

13. The catheter of claim 1 , wherein the penultimate distal section and the distal section are integrally formed from a single body.

14. 10. The catheter of claim 1, wherein the penultimate distal section comprises a first outer jacket segment having the first stiffness, and the distal section comprises a second outer jacket segment having the second stiffness.

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

16. 16. The catheter of claim 15, wherein the coiled wire comprises a first spacing between coils along the second-most distal portion and a second spacing between coils along the distal portion, the first spacing being less than the second spacing.

17. 16. The catheter of claim 15, wherein the coiled wire comprises a first wire diameter along the second-most distal portion and a second wire diameter along the distal portion, the first wire diameter being larger than the second wire diameter.

18. 10. The catheter of claim 1, further comprising a braided mesh tubular layer extending through at least a portion of the elongate catheter body, the braided mesh tubular layer having the first stiffness along the penultimate distal portion and the second stiffness along the distal portion.

19. 10. The catheter of claim 1, further comprising an inner liner extending through at least a portion of the elongate catheter body, the inner liner having the first stiffness along the penultimate distal portion and the second stiffness along the distal portion.

20. an elongated catheter body having an outer jacket; a first outer jacket segment disposed at a distal-most portion of the elongate catheter body, the first outer jacket segment having a first stiffness; a second outer jacket segment disposed at a second most distal portion of the first outer jacket segment, the second outer jacket segment having a second stiffness lower than the first stiffness; A catheter comprising:

21. an elongated catheter body; an outer jacket disposed along the elongate catheter body, the outer jacket having a distal region; the distal region has a gradient hardness in a distal direction along the longitudinal axis, decreasing in hardness toward the distal end of the catheter body and then increasing in hardness to the distal-most end of the catheter body. catheter.

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

23. 23. The catheter according to claim 22, wherein the hardness of the outer jacket in a portion of the outer jacket proximal to the distal end of the catheter body is 10A to 20A Shore hardness.

24. 22. The catheter of claim 21, wherein the distal region having a gradient hardness decreasing toward the distal end of the catheter body comprises a first outer jacket segment having a first hardness, the first outer jacket segment bonded to a second outer jacket segment having a second hardness at an interface region.

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

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

27. an elongate catheter body having a distal section, a proximal section, and an intermediate section therebetween; the distal portion has a first stiffness less than 50 gf / mm, the intermediate portion has a second stiffness, and the proximal portion has a third stiffness greater than 400 gf / mm; the second stiffness is in a stiffness change range between the first stiffness and the third stiffness; the intermediate section extends between 7-13 cm from the distal tip of the elongate catheter body and between 25-35 cm from the distal tip of the elongate catheter body; catheter.

28. 28. The catheter of claim 27, wherein the second range of change in stiffness of the intermediate section increases at a substantially linear rate from distal to proximal.

29. 28. The catheter of claim 27, wherein the entire second range of change in stiffness of the intermediate section increases at a rate of change from distal to proximal not exceeding 60 gf / mm per cm of catheter body length.

30. 28. The catheter according to claim 27, wherein the stiffness of the intermediate section increases at a rate of change of 10 to 60 gf / mm per cm of catheter body length from the distal side to the proximal side throughout the second range of change of stiffness.

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