Tubular structure with variable support

Abstract

To provide a flexible shaft including shafts having lumens, a shaft tubular structure including both of those that may be suitable for transiting mammalian lumens, including vascular and other lumens, including those of humans, such a structure having variable support, and a catheter.SOLUTION: A tubular structure with a variable support includes: a tubular member so that a flexible tubular member 150 can engage / disengage a structure support member or compress / release the same; and a structure support member accompanying the flexible tubular member covering the structure support member. The structure support member can be a tubular mesh, a stent, a frame, a skeleton, a braid, or other flexible frames. A fluid channel can be used for swelling / contracting the flexible tubular member. An assembly method and a use method are explained as well.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application is a non - provisional application from U.S. Application No. 62 / 125,294, filed on January 20, 2015, and U.S. Application No. 62 / 196,902, filed on July 24, 2015, the disclosures of which are incorporated herein by reference.

Background Art

[0002] These inventions relate to a flexible shaft, including a shaft having a lumen, a tubular structure of the shaft, including both of these, which may be suitable for passing through mammalian lumens, including vascular systems and other lumens, including those of humans, such a structure having variable support, and a catheter.

Summary of the Invention

Means for Solving the Problems

[0003] In one embodiment of the luminal member, the flexible luminal member includes an inner member and has an outer member outside the inner member. An intermediate member is between the inner member and the outer member, and the outer member is crushable around the intermediate member, and the outer member and the intermediate member are configured such that crushing of the outer member around the intermediate member increases the rigidity of the assembly. In one configuration, the inner member includes a lumen capable of receiving components including, but not limited to, for example, guide wires, dilators, therapeutic devices, interventional devices, and / or other components. In that or another configuration, the intermediate member can take several configurations. In one embodiment of the configuration of the intermediate member, the intermediate member can be a stent, for example, a stent generally understood in the medical industry as for implanting in the body, or the intermediate member can be a skeletal or movable support structure, for example, having linear or curved sections separated by open spaces, and can be bendable, flexible, or otherwise movable. The linear and / or curved sections can have a repeating or non-repeating pattern. In any of the foregoing or additional configurations, the intermediate member can be enclosed within an envelope, for example, one that prevents contact between the intermediate member and the vascular system into which the assembly can be inserted. In one configuration, the intermediate member can be enclosed within a cavity, in one embodiment, sealed within an annular cavity, and in another configuration, the intermediate member can be enclosed within a cavity that is completely sealed or closed, apart from one or more fluid passages that allow fluid to enter and exit the cavity.

[0004] In another embodiment of the luminal member, including any of the foregoing embodiments and configurations, the flexible luminal member includes an inner member and covers a portion thereof over which an intermediate structural member extends. The outer member extends over at least a portion, in this embodiment, over the entirety, of the intermediate structural member. In the relaxed state of the flexible luminal member, the intermediate structural member, the intermediate structural member has a first outer dimension, in at least some embodiments, an outer diameter, and the outer member has at least one second inner dimension, in at least some embodiments, an inner diameter less than the first outer dimension of the structural member. In such a configuration, the outer member may bias or press the intermediate structural member toward the inner member. For example, the outer member can have a non-inflated or non-expanded configuration that presses on the intermediate structural member. In one configuration, the unassembled outer member in the relaxed configuration has an inner diameter that is less than the outer diameter of the intermediate structural member in the configuration of the intermediate structural member when positioned on the inner member. In one embodiment, when the outer member is in the relaxed configuration and the unassembled outer member has an inner diameter less than the outer diameter of the intermediate structural member, the outer member can be sufficiently expanded or enlarged to slide over the intermediate structural member, positioned as desired, and then released, in which case the outer member returns toward the relaxed configuration and presses against the intermediate structural member. For example, the outer member is elastically flexible. The intermediate structural member stops further relaxation of the outer member, either alone or together with the inner member. When using the final assembly, when the device is in a usable state, the intermediate structural member is under compression from the elasticity of the outer member.

[0005] In another embodiment of the lumen structure, the lumen element or tubular element may combine with one or more additional elements to form a nested structure, at least two of which may be concentric, at least two of which may be tubular, and one or more structural support elements may be positioned intermediate the lumen or tubular element and the outer element. In one configuration of the structural support element, the structural support element has a skeletal or framework configuration, e.g., a plurality of interconnected straight or curved elements separated by open spaces. In one embodiment, the plurality of interconnected straight or curved elements may be highly interconnected, or sparsely interconnected, or may be interconnected therebetween. The straight or curved elements may be struts, each of which may be interconnected at a nodal point with one or more other struts at each of its ends. The nodal points may thereby have two struts contributing to a more sparsely interconnected structure, three struts contributing to a larger interconnected structure, four struts contributing to a larger interconnected structure, etc. Similarly, all nodal points may be able to have the same number of struts, or there may be groups of nodal points having different numbers of struts, with a given group having the same number of nodal points contributing to the level of interconnectivity. The structural support element may be able to have articulating members and / or may include one or more connectors, e.g., a cell structure interconnected by struts. In some embodiments, the structural support element may be a stent, e.g., a stent generally understood in the medical industry as for implantation into the body for any of several procedures. The stent may be an open cell stent, a closed cell stent, a hybrid cell stent, a slotted tube stent, or generally any other stent configuration including a mesh tube. Embodiments of stents include the flexible and expandable stent configuration shown in U.S. Patent No. 5,843,120. The structural support element is flexible and can return to its original shape without substantially losing its original shape. This may also be crushable and expandable without substantially losing its original shape.

[0006] In any of the examples of the intermediate structural members described herein, the intermediate structural member can be positioned within an enclosure, such as an outer tubular element, which is secured to an inner luminal element or tubular element such that the intermediate structural member is between the enclosure and the inner luminal element or inner tubular element. The enclosure may be sealed, for example, while still allowing fluid communication with a pressurized fluid source to expand or inflate the enclosure, such as using a liquid or gas. In one example, the expansion occurs via the expansion of an outer cover, such as an enclosure in the form of an outer tubular element. In some examples, the expansion releases the intermediate structural member and allows it to move more freely.

[0007] In any of the examples of the intermediate structural members, central structural members, stents, or tubular meshes referred to herein, such structural members can include inner and / or outer circumferential surfaces that can frictionally engage adjacent surfaces of the assembly. For example, when a structural member extends between an inner tubular element and an outer tubular element, the structure of the structural member that contacts one or the other of the inner tubular element and the outer tubular element can be pressed sufficiently into one or more of the surfaces to help limit relative movement therebetween. In some configurations, the surfaces on the structural member can be well-defined to have a perceptible angle or non-round surface that can help limit relative movement between the structural member and an adjacent tubular member. In other configurations, the surface finish on the structural member can help increase the frictional force required to move the structural member and one or more adjacent contact surfaces relative to each other. Such structural members can be made of metal, polished or unpolished, or other materials, including but not limited to nitinol, stainless steel, and similar metals.

[0008] In a further embodiment, which may be configured with any of the foregoing embodiments or configurations, an example of an intermediate structural member may be used in a variable stiffness catheter. In one embodiment, the catheter has a first flexibility in one state and a second flexibility in a second state. One state may be an inflated outer envelope, outer tube, or outer element around a structural support element, which is on a lumen element of the catheter. The outer element is expanded or inflated to allow for increased flexibility in the catheter. The outer element can be expanded or inflated in an amount sufficient to reduce the contact surface area between the outer element and the structural support element, which can leave any contact surface area between the outer element and the structural support element from 95% to zero. The reduced contact surface area can result in further flexibility of the lumen element, in this example, at least a portion of the catheter. A reduced or zero contact surface area between the structural support element and the outer element, for example, reduces or eliminates any contribution of frictional engagement between the structural support element and the outer element, and the remaining resistance to movement is contributed by the structural support element itself, the inner lumen element, and any contact surface area between the two of them, increasing the freedom of movement of the catheter in the region of the structural support element. When the outer element is contracted, reduced, compressed, or otherwise brought into further contact with the structural support element (e.g., by withdrawing fluid, or otherwise applying a vacuum or negative pressure, or by elastic tension in the outer element), for example, from further frictional contact between the outer element and one or more adjacent surfaces of the structural support element, the flexibility of the lumen element, in this example, at least a portion of the catheter is reduced. In one of the foregoing configurations, the expansion or inflation of the outer element occurs by the injection or intrusion of a medium, such as a fluid, such as a liquid like saline, into the region of the structural support element. Fluid pressure can be used to increase or expand the outer element, for example, increasing the outer dimension of the outer element such that the inner surface of the outer element no longer contacts one or more adjacent surfaces of the structural support element. In one embodiment, the outer element is expanded or inflated sufficiently to eliminate all contact with the structural support element. The fluid is a mixture of saline and a contrast agent, CO2 It can be a gas such as etc., or other suitable fluids. In some configurations, the release of the outer element from the structural support element also serves to release the structural support element from the inner lumen element of the catheter, for example, to reduce or eliminate frictional engagement between the structural support element and the adjacent surface of the inner lumen element of the catheter.

[0009] In a further embodiment that can be configured with any of the foregoing embodiments or configurations, an embodiment of the intermediate structural member may be used in a variable stiffness catheter, whereby the stiffness of a portion of the catheter is changed by compressing or contacting the structural support element, which is contained within the cavity or otherwise non-removable from the catheter without damaging the catheter, and is changed again by relieving the compression of the structural support element or removing contact with the structural support element. In one embodiment, the catheter has a structural support element within the cavity of the catheter, and the fluid is used in the cavity to allow or remove contact with the structural support element as desired. In one embodiment, the fluid is used to pressurize the cavity and reduce the amount of contact with the structural support element, and reducing the pressure increases the amount of contact with the structural support element. In one embodiment of reducing the pressure to increase the amount of contact with the structural support element, the inherent elasticity in the outer element can be used to increase the contact between the outer element and the structural support element when the fluid pressure is reduced. Alternatively, an increase in pressure can be used to increase frictional contact with such a structural support element, depending on the design of the assembly.

[0010] In another example, which may be configured with any of the foregoing examples or configurations, an example of an intermediate structural member may be used in a catheter having an inner lumen member, a structural support element, such as a stent, a tubular mesh, or other structural member, and the catheter may further include an outer tubular element that covers at least a portion of the structural support element, the outer tubular element being configured to be in a normally collapsed state. In one configuration, the normally collapsed state occurs through elastic contraction of the material of the outer tubular element, and in one configuration, the elastic contraction applies pressure to the structural support element. The pressure on the structural support element creates a frictional force between the structural support element and the material of the outer tubular element to prevent movement therebetween. In one example, the outer tubular element is expanded and disposed to cover the structural support element on the lumen element and is then permitted to release or collapse around the structural support element, for example, by applying an inward pressure to the structural support element. The outer tubular element may have a substantially uniform geometry and material throughout its length, but may also have variations in different properties incorporated into the outer tubular element over its length and / or circumference, such as durometer, thickness, geometry, and structure (e.g., single piece versus multiple pieces).

[0011] In a further embodiment that can be configured with any of the foregoing embodiments or configurations, an intermediate structural member may be used in a catheter having a structural support member positioned between an inner lumen member, an outer tubular member, and the inner lumen member and the outer tubular member, whereby increasing or decreasing the contact between one or more surfaces of the structural support member and one or the other of the inner lumen member and the outer tubular member changes the stiffness of a portion of the catheter. Increasing or decreasing the contact can be done by inflation or expansion, for example, by inflation or expansion of the outer tubular member and / or the inner lumen member sufficient to reduce the contact surface area of one or more elements with one or more surfaces of the structural support member. In one embodiment, the flexibility of the catheter can be increased, for example, by expanding the outer tubular member relative to the structural support member by injecting fluid into a cavity around the structural support member. The flexibility of the catheter can be decreased, for example, by reducing the expansion by removing fluid from the cavity around the structural support member.

[0012] In another embodiment that can be configured with any of the foregoing embodiments or configurations, the catheter has a tubular mesh having a plurality of longitudinally extending struts interconnected by a plurality of connecting struts. Each of the plurality of connecting struts can connect respective circumferentially or arcuately spaced longitudinally extending struts. In one embodiment, a series of aligned longitudinally extending struts are circumferentially or arcuately spaced from another series of aligned longitudinally extending struts and longitudinally offset. In another embodiment, each angle between a connecting strut and a respective longitudinally extending strut is an acute angle. An acute angle can be any angle between greater than zero degrees and less than 90 degrees.

[0013] In a further embodiment, which may be configured with any of the foregoing embodiments or configurations, an intermediate structural member may be used between the inner and outer tubular elements to provide variability in the rigidity of the assembly. In one configuration, the intermediate structural member is a flexible cylindrical member comprising a plurality of elements, and the cross-section of the flexible cylindrical member includes at least two elements arranged around the circumference of the cylinder, and in many embodiments, at least three elements. In one configuration, the plurality of elements are interconnected or interconnected within the intermediate structural member. In a further configuration, the plurality of elements have a discrete length, and in another configuration, each of the plurality of elements has a length that is less than the full length of the structural support member, and in one configuration, none of the plurality of elements extends proximally to a manual control device or a proximal catheter hub. In another configuration, the plurality of elements may be of different sizes and include different cross-sectional areas, and the plurality of elements may be grouped and distinguishable, and one group may have the same characteristics that are different from those of another group, such as different cross-sectional areas, different sizes, different lengths, and the like. In one embodiment, there are more elements from one group in the intermediate structural member than the number of elements from another group. In one embodiment, the plurality of elements are uniformly distributed covering the cylinder when in a relaxed or neutral state. In one embodiment, the intermediate structural member includes two groups of interconnected elements, namely, a first group arranged in cross-section to have a first number of elements that are substantially uniformly distributed around the circumference of the cylinder, and a second group arranged to have a second number of elements that are substantially uniformly distributed, and in one configuration, includes 6 from the first group and 12 from the second group. The plurality of elements forming the intermediate structural member are, in one embodiment, arranged in a substantially symmetric form when in a relaxed or neutral configuration.

[0014] In a further embodiment, which may be configured with any of the foregoing embodiments or configurations, variable stiffness shafts, such as, for example, tubular elements, luminal elements, catheters, and the like, can be changed from a first configuration, such as the shape configuration as manufactured, to a second different shape configuration, and may include a structural support member arranged relative to the shaft to help maintain the shaft in the second shape configuration. The structural support member can help maintain the shaft in the second shape configuration, regardless of the application of some external force or even in spite of the manufacturing memory, such as the original manufacturing shape. In one configuration, the structural support member can be in a first configuration, such as a release or flexible configuration, and the shaft at the location of the structural support member can be changed or reshaped to the second shape configuration, and then the structural support member is fixed or cured, crimped, or clamped to hold that configuration. As a result, the shaft in the region of the structural support member then maintains its second shape configuration, and that portion of the shaft is prevented from returning to its first shape configuration, even in the presence of an external force to the shaft in the first configuration or its native memory. In one embodiment, a catheter can be introduced into a tortuous body lumen using a structural support member associated with the catheter in a release or flexible configuration. Once the catheter reaches the desired position within the body lumen, the structural support member can be cured, crimped, or clamped in the second shape that was present at the time, regardless of any twist or bend imposed on it while passing through the body lumen, and that portion of the catheter associated with the structural support member is held in the same shape. During curing or while the catheter portion has increased stiffness, little or no force is applied by the catheter to the blood vessel wall. Thus, the structural support member helps impart the shape of the body lumen in which it is positioned to that portion of the catheter, giving that portion of the catheter a shape memory that is maintained even in the presence of an external force and / or any shape memory implanted during manufacture. The outer tubular element also serves to fix, cure, crimp, or clamp the structural support member in these embodiments.Accordingly, a flexible shaft element, including a medical catheter, can be hardened and maintained in a number of configurations regardless of the starting or manufacturing configuration.

[0015] As used herein, "outer" in connection with an outer tubular member, outer member, outer element, outer cover, outer envelope, or outer wall refers to a position relative to a structural support member, and "outer" in this context does not mean outermost.

[0016] These and other examples are described more fully below in conjunction with the drawings, a brief description of which follows. The present invention provides, for example, the following. (Item 1) A flexible lumen assembly configured to pass through a body lumen, comprising a longitudinally extending flexible lumen member, a structural support member extending outside a portion of the flexible lumen member, and an outer member covering the structural support member, wherein the outer member is configured to selectively apply pressure to the structural support member. (Item 2) The assembly according to item 1, wherein the outer member is configured to releasably compress the structural support member. (Item 3) The assembly according to any of the preceding items, wherein the structural support member is a tubular structural support member. (Item 4) The assembly according to any of the preceding items, wherein the structural support member is a tubular mesh. (Item 5) The assembly according to item 4, wherein the tubular mesh includes a non-random tubular mesh. (Item 6) The assembly according to any of the preceding items, wherein the structural support member is positioned within a cavity between the flexible lumen member and the outer member. (Item 7) The assembly according to any of the preceding items, wherein the outer member substantially encapsulates the structural support member. (Item 8) The assembly according to any of the preceding items, further comprising a passage for a fluid to enter and exit the region between the structural support member and the outer member. (Item 9) The outer member is flexible, the assembly according to any of the preceding items. (Item 10) The outer member is elastically flexible, the assembly according to any of the preceding items. (Item 11) The outer member is a balloon, the assembly according to any of the preceding items. (Item 12) The outer member is configured to have an expanded configuration and a reduced configuration, and in the reduced configuration, the outer member applies pressure to the structural support member, the assembly according to any of the preceding items. (Item 13) The structural support member is concentric, layered, or positioned so as to be sandwiched between the lumen member and the outer member, the assembly according to Item 12. (Item 14) The assembly is configured such that the application of pressure to the structural support member by the outer member presses the structural support member against the lumen member, the assembly according to any of Items 12 - 13. (Item 15) The assembly is configured such that the expansion of the outer member reduces at least a portion of the pressure on the structural support member, the assembly according to any of Items 12 - 14. (Item 16) The assembly is configured such that the expansion of the outer member reduces all of the pressure on the structural support member, the assembly according to Item 15. (Item 17) The assembly is configured such that the step of reducing the pressure on the structural support member includes the step of reducing the contact surface area between the outer member and the structural support member, the assembly according to any one of Items 15 or 16. (Item 18) The structural support element includes a plurality of components, and a cross-section of the structural support element includes at least two components, the assembly according to any of the preceding items. (Item 19) The cross-section of the structural support element includes at least three components, the assembly according to item 18. (Item 20) At least two of the components have different sizes, the assembly according to any of items 18-19. (Item 21) At least two of the components have different cross-sectional areas, the assembly according to item 20. (Item 22) At least two of the components have different lengths, the assembly according to item 20. (Item 23) The structural support element includes at least a first group and a second group of components, and each of the components within the first group is different from each of the components within the second group, the assembly according to any of items 18-22. (Item 24) There are more components within the second group than within the first group, the assembly according to item 23. (Item 25) There are twice as many components within the second group as within the first group, the assembly according to any of items 23-24. (Item 26) Each of the components within the first group is coupled to each of the components within the second group, the assembly according to any of items 23-25. (Item 27) The at least two components are connected to each other, the assembly according to any of items 18-26. (Item 28) The at least two components are connected to each other at their respective ends, the assembly according to any of items 18-27. (Item 30) The structural support element extends in a longitudinal direction by a first distance, and one of the components includes a component less than the first distance, the assembly according to any one of items 18-28. (Item 31) Each of the components in the structural support element includes a respective length less than the first distance, the assembly according to item 30. (Item 32) The structural support element includes at least three components having a first cross-sectional area and at least three components having a second cross-sectional area less than the first cross-sectional area, the assembly according to any one of items 18-31. (Item 33) The components are distributed substantially uniformly around the structural support element, the assembly according to any one of items 18-32. (Item 34) Each of the components is coupled to at least one other component, the assembly according to any one of items 18-33. (Item 35) Each of the components is coupled to at least one other component at each end, the assembly according to item 34. (Item 36) Each of the components extends substantially linearly, the assembly according to any one of items 18-35. (Item 37) The at least two components include a first and a second component, and the first and second components are coupled to each other at an angle, the assembly according to any one of items 18-36. (Item 38) The angle is greater than zero and less than 90°, the assembly according to item 37. (Item 39) The flexible lumen member includes reinforcement, the assembly according to any of the preceding items. (Item 40) The reinforcement includes either a coil or a braid incorporated into the flexible lumen member, the assembly according to item 39. (Item 41) The flexible lumen member is substantially incompressible under normal operating conditions, the assembly according to any of the preceding items. (Item 42) The structural support member is a stent, the assembly according to any of the preceding items. (Item 43) The assembly forms part of a catheter, the assembly according to any of the preceding items. (Item 44) The assembly according to any of the preceding items, further comprising a catheter hub having an injection port. (Item 45) The assembly according to any of the preceding items, further comprising a fluid lumen coupled to the space between the outer element and the structural support member and extending eccentrically from the central axis of the assembly. (Item 46) The fluid lumen extends along the outer wall of the flexible lumen member, the assembly according to item 45. (Item 47) The assembly according to any of the preceding items, configured to receive a guide wire. (Item 48) The assembly according to any of the preceding items, configured to receive a dilator element. (Item 49) The assembly according to any of the preceding items, configured to receive a syringe. (Item 50) A flexible lumen assembly configured to pass through a body lumen, comprising a longitudinally extending lumen element, a tubular mesh extending longitudinally and circumferentially around a portion of the lumen element, and a tubular member at least partially sealed to the lumen element, wherein all portions of the tubular mesh are positioned between respective surfaces of the lumen element and respective surfaces of the tubular member. (Item 51) The lumen element includes reinforcement, the assembly according to item 50. (Item 52) The assembly according to any one of items 50-51, wherein the lumen element is substantially incompressible under normal operating conditions. (Item 53) The assembly according to any one of items 50-52, wherein the tubular member is elastically flexible. (Item 54) The assembly according to any one of items 50-53, wherein the tubular member is configured to be biased to press the tubular mesh. (Item 55) The assembly according to any one of items 50-54, wherein the tubular member is flexible enough to extend between individual components of the tubular mesh. (Item 56) The assembly according to any one of items 50-55, wherein the tubular mesh is configured within the assembly to have an inner diameter substantially the same as the outer diameter of adjacent lumen elements. (Item 57) The assembly according to any one of items 50-56, wherein the tubular mesh includes a plurality of components, and the plurality of components include components that extend longitudinally when the lumen element extends substantially straight. (Item 58) The assembly according to item 57, wherein a first plurality of longitudinally extending components extend circumferentially around the tubular mesh, another plurality of longitudinally extending elements extend circumferentially around the tubular mesh, and are longitudinally shifted from the first plurality of longitudinally extending elements. (Item 59) The assembly according to item 58, wherein the first plurality of longitudinally extending elements comprise at least three longitudinally extending elements. (Item 60) The assembly according to any one of items 58-59, wherein the first plurality of longitudinally extending elements include six longitudinally extending elements. (Item 61) The assembly according to any one of items 57 - 60, further comprising a plurality of angularly extending elements that extend at an angle other than parallel to the longitudinally extending element when the lumen element extends substantially straight. (Item 62) The assembly according to item 61, wherein each of the angularly extending elements includes respective first and second ends, and each first and second end is connected to a respective longitudinally extending element. (Item 63) The assembly according to any one of items 61 - 62, wherein the longitudinally extending element has a size different from the size of the angularly extending element. (Item 64) The assembly according to item 63, wherein the longitudinally extending element has at least one of a larger cross - sectional area or a longer length. (Item 65) The assembly according to any one of items 61 - 64, wherein the angularly extending element extends at an angle with respect to each of the longitudinally extending elements that is greater than zero and less than 90°. (Item 66) The assembly according to item 65, wherein the angle is between 5° and 30°. (Item 67) The assembly according to any one of items 50 - 66, wherein the tubular mesh is a stent. (Item 68) The assembly according to any one of items 50 - 67, wherein the lumen element is a cylindrical tubular element. (Item 69) The assembly according to any one of items 50 - 68, wherein the lumen member is configured to receive a guide wire. (Item 70) The assembly according to any one of items 50 - 69, further comprising a lumen for receiving a fluid, configured to allow the fluid to enter the space occupied by the tubular mesh between the tubular element and the lumen element. (Item 71) A catheter assembly configured to pass through a body lumen, comprising: a lumen element extending in a longitudinal direction; a structural support extending longitudinally and around a portion of the lumen element; and a tubular element at least partially sealed to the lumen element and extending on a side surface of the structural support outside the lumen element, wherein the tubular element contacts at least a portion of the structural support and is configured to provide a first rigidity for the lumen element adjacent to the structural support, and the lumen element has a second rigidity lower than the first rigidity when contact between the tubular element and the at least a portion of the structural support is reduced. (Item 72) The catheter assembly according to item 71, wherein the tubular element is configured to be expandable. (Item 73) The catheter assembly according to any one of items 71-72, wherein the tubular element is configured to be elastically flexible and to apply pressure to the structural support when the tubular element is in a relaxed state. (Item 74) The catheter assembly according to item 73, wherein in the relaxed state, the tubular element presses against the structural support contacting the adjacent surface of the lumen element. (Item 75) The catheter assembly according to item 74, wherein the tubular element includes a surface portion extending between components of the structural support. (Item 76) The catheter assembly according to any one of items 71-75, wherein the lumen element includes sufficient reinforcement to make the lumen element non-compressible under normal operating conditions. (Item 77) The catheter assembly according to any one of items 71-76, wherein the support structure includes a plurality of longitudinally extending struts and a plurality of angled struts. (Item 78) The catheter assembly according to any one of items 71-77, wherein the structural support includes a repeating pattern of longitudinally extending struts and angled struts. (Item 79) The struts extending in the longitudinal direction are grouped and distributed circumferentially around the structural support, and one group of struts extending in the longitudinal direction is laterally spaced from a second group of struts extending in the longitudinal direction and offset circumferentially, the catheter assembly according to item 78. (Item 80) A catheter assembly configured to pass through a body lumen, comprising a longitudinally extending lumen element, a structural support extending longitudinally and around a portion of the lumen element, and a tubular element at least partially sealed to the lumen element and extending on a side surface of the structural support outside the lumen element, wherein the lumen element has a variable stiffness section adjacent to the structural support, the variable stiffness section being bendable into first and second configurations, the variable stiffness section having a first configuration in which the variable stiffness section has a first flexibility and a second configuration in which the variable stiffness section has a second flexibility less than the first flexibility, the variable stiffness section being in the second configuration having the first flexibility, and when the variable stiffness section is changed to the second flexibility, a difference in bending force presented by the variable stiffness section between the first flexibility and the second flexibility is less than 50%. (Item 81) The catheter assembly according to item 80, wherein the variable stiffness section is configured to substantially maintain the second configuration while the variable stiffness section has the second flexibility. (Item 82) The catheter assembly according to any one of items 80 - 81, wherein the variable stiffness section is configured to have the second flexibility by compressing the structural support between the lumen element and the tubular element. (Item 83) The catheter assembly according to any one of items 80 - 82, wherein the structural support is a non - random tubular mesh. (Item 84) The variable stiffness section is configured to have the first flexibility by expanding the tubular element so as to reduce the amount of contact between the tubular element and the structural support, the catheter assembly according to any one of items 80 - 83. (Item 85) The difference in the bending force is less than 30%, the catheter assembly according to any one of items 80 - 84. (Item 86) The difference in the bending force is less than 10%, the catheter assembly according to any one of items 80 - 85. (Item 87) A step of assembling the structural support on the flexible lumen such that the structural support extends longitudinally along at least a portion of the flexible lumen and around the flexible lumen, a step of inserting a portion of the flexible lumen and the structural support into an enlarged tubular element, and a step of releasing the enlarged tubular element such that the enlarged tubular element covers and crushes at least a portion of the structural support, a method of assembling a flexible lumen assembly suitable for passing through a body lumen. (Item 88) The method according to item 87, further comprising the step of expanding the tubular element. (Item 89) The method according to any one of items 87 - 88, further comprising the step of sealing an end of the tubular element to an adjacent portion of the lumen element. (Item 90) The method according to any one of items 87 - 89, further comprising the step of sealing the tubular element to an adjacent portion of the lumen element sufficient to withstand the fluid pressure applied between the tubular element and the lumen element. (Item 91) The method according to any one of items 87 - 90, further comprising the step of providing a fluid lumen for providing fluid into the space between the tubular element and the flexible lumen. (Item 92) The method according to item 91, wherein the step of providing a fluid lumen includes the step of providing a fluid lumen along a side surface of the lumen element. (Item 93) Providing a luminal member and an outer member disposed to cover at least a portion of the luminal member with a structural support therebetween, the outer member being at least partially sealed to an adjacent surface of the luminal member sufficient to withstand fluid pressure within a space around the structural support, the luminal member having a first flexibility in a region of the structural support; and increasing the flexibility in the region of the structural support by removing at least a portion of the outer member from contact with the structural support, a method of varying the flexibility of a luminal element configured to pass through a body lumen. (Item 94) The method of item 93, further comprising providing an inflation lumen for receiving fluid from a proximal portion of the luminal element and providing fluid to the space around the structural support. (Item 95) The method according to any one of items 93 - 94, further comprising reducing the stiffness of the region of the structural support by removing fluid from the space around the structural support. (Item 96) The method according to any one of items 93 - 95, further comprising providing the outer member disposed to cover the structural support in compression of the structural support. (Item 97) The method according to any one of items 93 - 96, further comprising increasing the flexibility in the region of the structural support by removing substantially the entire outer member from contact with the structural support. (Item 98) The method of item 97, wherein removing substantially the entire outer member from contact with the structural support includes moving substantially the entire outer member substantially simultaneously. (Item 99) The method according to any one of items 93 - 98, further comprising applying pressure to the structural support with the outer member at a substantially outer radial position that is half of the radial distance from the center of the assembly to the outer surface of the assembly. (Item 100) The method according to any one of items 93 - 99, further comprising the step of providing a tubular mesh for the structural support. (Item 101) The method according to any one of items 93 - 100, further comprising the step of providing the lumen element as a catheter tube with a lumen sufficient to receive a guide wire or dilator assembly. (Item 102) The method according to any one of items 93 - 101, further comprising the step of providing a fluid injection port for the assembly.

Brief Description of the Drawings

[0017]

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DETAILED DESCRIPTION OF THE INVENTION

[0018] This specification, interpreted in conjunction with the drawings, describes embodiments of apparatuses and methods incorporating one or more aspects of the invention in such a manner that one of ordinary skill in the art can make and use the invention. The embodiments provide the best mode contemplated for carrying out the invention, but it is to be understood that various modifications can be achieved within the parameters of the invention.

[0019] Examples of lumens or tubular structures and methods of making and using lumens or tubular structures are described. Depending on which one or more features are incorporated into a given structure or a given method, benefits can be achieved in the structure or method. For example, a tubular structure using inner and outer tubular elements, which may or may not be concentric, may be configured to have one stiffness in a first state and another stiffness in another state. For example, it may be relatively stiff when in a relaxed state and less stiff when one or more elements within the tubular structure are actuated. The inner and outer tubular elements may also be configured with an intermediate structural framework that can provide a more secure support assembly when in a support configuration, for example, when the inner and outer tubular elements and the structural framework are all compressed together. The configuration of the inner and outer tubular elements may also be used, for example, to more firmly and releasably secure the tubular elements in a desired geometry to assist the passage of another element, such as an intervention device or other device, during a procedure.

[0020] Examples of inner and outer lumen or tubular elements and intermediate structural frameworks can also be used to provide a more secure support structure per unit length of the assembly of the tubular elements and the structural framework. One or more of the inner and outer tubular elements and the elements of the structural framework can be configured to incorporate a desired flexibility or rigidity per unit length. In one embodiment, a structural framework that provides a given flexibility or rigidity per unit length can be used between the inner and outer tubular elements, and different structural frameworks can be used to manufacture or assemble another combination having different flexibilities or rigidities per unit length. In another embodiment, the structural framework can be used to provide a given flexibility or rigidity in response to the expansion or contraction of the components adjacent to the structural framework. In one configuration, the structural framework can provide increased rigidity when an adjacent component presses against it, for example, when contraction brings the component into contact with the structural framework, and can provide decreased rigidity when the adjacent component has a reduced amount of contact with the structural framework.

[0021] In some configurations of the lumen or tubular structure, improvements can also be achieved in the assembly, and in some configurations, an assembly can be produced having an assembled or final configuration with a desired rigidity or flexibility, and such rigidity or flexibility can be selectively or intermittently reduced through one or more actions. For example, an assembly can be produced in an embodiment where an elastic tubular structure presses against a structural framework when a component in a relaxed or neutral state presses against the structural framework. In another embodiment, the user can reduce the rigidity or flexibility in the assembly by releasably expanding or enlarging at least one of the tubular structures that can reduce the rigidity or flexibility in at least a portion of the assembly.

[0022] These benefits or other advantages will become more apparent upon consideration of the description of the embodiments herein. However, it should be understood that not all of the benefits or features discussed with respect to a particular embodiment must be incorporated into a tubular structure, component, or method in order to achieve one or more of the benefits contemplated by these embodiments. Additionally, it should be understood that the features of an embodiment may be incorporated into a tubular structure, component, or method to achieve a given benefit to some degree, even if the benefit is not optimal as compared to other possible configurations. For example, one or more benefits may not be optimized for a given configuration due to cost reduction, to achieve efficiency, or for other reasons known to an individual determining a particular product configuration or method.

[0023] Examples of some tubular structure configurations and methods of making and using tubular structures are described herein, and some have particular benefits when used together. However, even if these devices and methods are considered together at this time, there is no requirement that they be combined exactly as described, used together in an exact combination, or that one component or method be used only with any other component or method, or only with the combinations as described. Additionally, it will be understood that a given component or method may be combined with other components or methods not explicitly discussed herein while still achieving a desired result.

[0024] A catheter incorporates one or more of the features and can derive some of the benefits described herein, and is an example of a tubular structure, specifically for use as a blood vessel catheter. Catheters used for navigation and for support of other components within a blood vessel have several configurations, and such catheters can benefit from one or more of those of the present invention. Tubular structures other than catheters can benefit from one or more of those of the present invention.

[0025] As used herein, "substantially" and "about" are intended to mean a specified parameter or configuration that is plus or minus 10%.

[0026] A lumen or tubular structure can be incorporated into several devices that may include devices and methods for varying the stiffness or flexibility of such lumen or tubular structure, or the support provided by such lumen or tubular structure. The present examples described herein relate to a lumen or tubular structure for a catheter, for example, a catheter for traversing a vascular system including the human vascular system. However, it is understood that the components and assemblies described herein can be used in a variety of structures and applications, including catheters for other uses and other lumens or tubular structures. The present examples will include vascular catheters, but other structures are also applicable.

[0027] In one embodiment of a lumen or tubular structure (Figs. 1-7), catheter assembly 100 includes a catheter having a shaft 102. Catheter assembly 100 is configured to be sufficiently flexible to pass through the human vasculature. The catheter assembly further includes a catheter hub 104. The catheter hub can assume several configurations and may be used to receive and provide several structures as well as components and / or fluids in the use and application of the catheter and, as will be understood by those skilled in the art, may be used with several other instruments and / or components. In this embodiment, the catheter hub includes an inflation or injection port 106 for receiving an inflation or injection device, which in this embodiment is depicted as a syringe 108 having a syringe body or barrel 110 and a plunger 112 for injecting fluid into or withdrawing fluid from the barrel 110, for example. The syringe holds saline (in the embodiments of Figs. 8-9 described more fully below) and will be used to inject into or withdraw from catheter hub 104 or the lumen. The syringe is mounted or secured in inflation port 106 in a conventional manner.

[0028] The catheter hub 104 includes a body 114 that extends longitudinally and partially defines the major axis of the catheter hub at the proximal portion of the catheter. The catheter hub body 114 includes an inner wall that defines a bore 116 extending from the proximal end 118 of the catheter hub to the distal end 120 of the catheter hub, and is configured in a conventional manner for receiving devices and materials, and in this embodiment may receive an expander 122 as shown. The expander can be omitted or replaced by a cover or other components. In this embodiment, the expander 122 includes an expander hub 124 that is mounted on or affixed to the proximal end 118 of the catheter hub, and an expander shaft 126 that extends longitudinally within the catheter hub inside the wall 116 or within the catheter shaft 102. In this embodiment, the expander shaft 126 extends through the distal end portion 128 of the catheter shaft and includes an expander tip 130. In this embodiment, the expander tip extends beyond the distal end surface 132 of the catheter shaft, for example, at a distance typical for a catheter and expander assembly. The expander 122 is a conventional expander configured for use with a catheter such as any of those described herein. In one embodiment, the expander is configured to receive a guide wire or other guide device (not shown) through the central lumen of the expander.

[0029] The inflation port 106 includes an inner wall 134 that defines a bore extending to the central bore 116 of the catheter hub. The inflation bore 134 is in fluid communication with the central bore 116, and fluid from the inflation port 106 can flow into and out of the central bore 116 around the expander shaft by the operation of the syringe 108 and under the influence of any other forces or influences in the design of the catheter. The interference fit between the distal end of the expander and the distal end of the catheter shaft holds the fluid within the central bore 116.

[0030] The catheter shaft 102 includes a lumen member, in this embodiment, a tubular member 150. The proximal portion 152 of the tubular member 150 is mounted, secured, and sealed within the distal portion 120 of the catheter hub in a conventional manner. The tubular member extends longitudinally from the catheter hub to the distal end portion 128 of the catheter shaft and specifically terminates at the distal end surface 132 in this embodiment. The tubular member is formed to be sufficiently flexible to pass through the human vascular system, including the heart, peripheral, and cerebrovascular systems, as well as body lumens, which may be serpentine. The tubular member 150 has a substantially circular cross-section in this embodiment, but can have other cross-sectional profiles. The tubular member is substantially coaxial with the central axis of the catheter hub 104 when in the shape illustrated in FIGS. 1 and 2.

[0031] The tubular member 150 is substantially cylindrical over substantially its entire length. The tubular member also has a substantially uniform wall thickness, for example, from about 0.003 inches to about 0.020 inches, over substantially its entire length and also has a substantially uniform inner diameter, for example, from about 0.025 inches to about 0.100 inches, over its entire length from just proximal of the distal end portion 128 to just inside the catheter hub, as will be more fully described below. However, other tubular geometries may be used and it is understood that the catheter shaft can be formed with other cross-sectional profiles. Alternatively, the catheter shaft 102 can have a structure and geometry other than those described herein, and such other structures and / or geometries may include a lumen, as desired, for the passage of devices or fluids such as, for example, guidewires, tubular devices, instruments, saline, contrast agents, and other devices and materials.

[0032] The tubular member 150 is formed from a suitable material that can be determined by the intended use. In this embodiment, the tubular member 150 is formed from an elastomeric material conventional for vascular catheters, such as PEBA, polyurethane, or similar materials. The inner and outer surfaces of the tubular member are configured to have the desired finish for their intended purposes. In this embodiment, the outer surface 154 (FIG. 3) is configured to allow for easy movement through other devices and through the vascular system as needed. The inner surface 156 allows for easy movement of fluid flow within the tubular member and of any other desired devices or materials, such as the dilator shaft 126 and the intervention device / instrument.

[0033] In the illustrated embodiment, the tubular member 150 includes a reinforcing element. In this embodiment, the reinforcing element includes one or more helical coil structures 158 (FIGS. 3 and 4). In this embodiment, the helical coil 158 is a single continuous helical coil that extends from inside the catheter hub 104 to a point adjacent the distal end portion 128 of the tubular structure. The helical coil can form a conventional form of reinforcement for a conventional catheter tube and can be stainless steel, such as 304 or 316 stainless steel, with a diameter of 0.001 inches to 0.007 inches and a pitch of 0.003 inches to 0.020 inches. Additionally, the coil can be formed from wire with a non-circular cross-sectional shape, such as a rectangular or oval cross-section. The coil can be formed from other materials, with other coil and strand diameters and / or with other pitches, to provide the desired strength, reinforcement, and / or rigidity. Other reinforcing devices can be used as an alternative or in addition. For example, a braided structure can be used. In this embodiment, the reinforcing element is incorporated into or co-extruded with the tubular member 150, as is conventional, for example.

[0034] The tubular member 150 extends distally to a distal end portion 128 where the coil 158 terminates. The elastomeric tubular member continues distally at a converging portion 160, which then terminates at a cylindrical or annular wall portion 162. The distal end portion 128 is formed with a diameter to provide an interference fit with the dilator tip 130, both being configured to provide a desired interference fit.

[0035] The geometry and structure of the tubular member 150 extends uninterrupted from the proximal end portion to the distal end portion, in this embodiment, except for one or more openings or fluid apertures 164 (FIGS. 3 - 4). The openings 164 extend completely through the tubular wall between the strands of the coil and, in this embodiment, provide a fluid path between the inside and outside of the tubular member at the location of an opening within an outer tubular member more fully described below. The fluid apertures allow fluid, e.g., from the inflation port 106, to pass from the lumen within the tubular member 150 to a cavity or recess or balloon outside the tubular member 150. In this embodiment, there are two fluid apertures through the wall of the tubular catheter member.

[0036] The use of fluid to expand and / or contract the volume of a cavity containing a structural support element allows for varying states of the tubular structure. For example, expansion and contraction, or reduction of the applied pressure or vacuum, can change the rigidity or flexibility of the structure. In one embodiment, expanding a cavity containing a structural support element can increase the flexibility of the catheter in the region of the structural support element, and reducing the pressure, applying a vacuum, or allowing the cavity to contract can decrease the flexibility of the catheter. In this way, the catheter can have selective adjustability of its rigidity or flexibility.

[0037] The configuration of the tubular member 150 as an inner layer or inner tubular element can be configured in several ways. Flexibility can be enhanced along the length, including the distal portion of the tubular element, by varying the durometer of the material according to its length and / or by adjusting the wall thickness of the tubular member according to the length or distance from the catheter hub. Alternatively and / or in addition, reinforcement can be modified according to the distance from the catheter hub, for example, by varying the geometry or spacing of the material. In the case of a helical coil embodiment, the pitch of the coil can be changed, or the diameter of the coil or strand element can be incorporated into the tubular member. The reinforcing material can be metallic or non-metallic and can be stainless steel, nitinol, polymeric fibers, metal wires with radiopaque properties, tantalum, tungsten, or an alloy of these materials or other materials.

[0038] The catheter 100 further includes an adjustable member outside the catheter tubular member 150 that extends over at least a portion of the outer surface of the tubular member 150. In the region of the adjustable member, the catheter tubular member 150 is the inner tubular member with respect to the outer adjustable member. In some configurations, the adjustable member is used to selectively establish or vary the flexibility or rigidity of a portion of the catheter, for example, a portion of the catheter around which the adjustable member is positioned. The adjustable member can be used to sandwich one or more underlying components within an envelope, cavity, or region over which or around which the adjustable member extends. The adjustable member can be used to establish or increase an internal force that must be overcome to increase the contact surface area between adjacent elements and to move or change the geometry of a portion of the catheter. The adjustable member can also be used to effectively separate itself from a portion or the whole of the underlying component, which can allow for the separation of additional components from each other and can also allow for the positioning adjustment or other adjustment of one or more underlying components. The adjustable member can be configured to be in a first state normally, or a second state normally (e.g., having memory characteristics), for example, normally generating contact with the underlying component, or normally separating from the underlying component, or normally applying pressure, or normally being released from applying pressure. Alternatively, the adjustable member can be configured to remain in a given state until acted upon, for example, without any memory characteristics. In the embodiments described herein, the adjustable member is normally configured to be in a crushing, shrinking, or applying mode in which pressure or force is applied by the adjustable member to one or more underlying components. The adjustable member is adjusted, for example, by an active action to change the adjustable member from its crushing, shrinking, or applying mode, at least in part, to reduce the contact surface area between the adjustable member and the underlying component. In this embodiment, the adjustable member is movable radially.Also, in the present embodiment, the adjustable member applies pressure to the basic component substantially simultaneously along the entire length of the basic component.

[0039] An example of the adjustable member (Figs. 1-9 and 11A-B) is the tubular member 200. In the present embodiment, the tubular member 200 extends covering a part of the catheter shaft 102. The tubular member 200 forms an outer tubular member (outer tube) to a certain extent outside the adjacent part of the catheter shaft 102. However, it is understood that one or more other components may be outside the outer tubular member 200. The proximal end 202 of the outer tube is fixed circumferentially around the entire part of the proximal end 202 of the outer tube to the adjacent part of the catheter tubular member 150. The proximal end can be fixed, for example, thermally, or adhesively, sealed, welded, adhered, or otherwise fixed to the outer surface of the catheter tubular member 150 in a manner similar to concentric catheter tubes that can be fixed to each other in a conventional catheter. With the present outer tube, the outer tube is fixed to the catheter tubular member 150 at both ends of the outer tubular element in such a way that the joint can withstand the expected internal fluid pressure generated between the outer tubular member and the catheter tubular member 150.

[0040] The outer tube 200 extends distally around the distal end portion 128 of the catheter tubular member 150, from the proximal end portion 202 that covers the catheter tubular member 150 to the distal end portion 204 of the outer tubular member. The distal end portion 204 is sealed, welded, adhered, or otherwise fixed to the adjacent distal end portion of the catheter tubular member, similar to the proximal end portion 202. The outer tube 200 forms a cavity, envelope, or annular space 206 between the proximal end portion and the distal end portion, between the inner surface 208 of the outer tube 200 and the opposite or facing outer surface 154 of the inner tubular member 150. The cavity 206 forms a balloon in this embodiment that can be expanded or inflated according to the flexibility and strength of the outer tubular member 200. In some configurations, the adjacent portions of the inner tubular member may also be flexible enough to provide some additional expansion or dilation inwardly toward the central axis of the catheter, but this configuration has the inner wall of the inner tubular member not significantly changing in diameter under the currently considered pressure within the cavity 206, and remaining at a constant diameter before, during, and after the expansion or dilation of the outer tubular element, and before, during, and after the contraction or complete collapse of the outer tubular element, with the inner tubular member 150 having an incorporated coil 158.

[0041] In this embodiment, the outer tube 200 is of a monolithic structure, flexible, and formed of a material that can increase in diameter in response to the application of an internal pressure (e.g., about 1 - 200 psi) between the outer tube 200 and the inner tube 150 (i.e., increase in diameter when the outer tube is substantially cylindrical or circular). The outer tubular element functions as a balloon that can expand outwardly in response to the application of an internal pressure, e.g., a pressure generated by a fluid, in one embodiment, a relatively non - compressible fluid. The outer tubular element 200 is configured to have a maximum expandable diameter under normal operating conditions by selecting a material that, for example, essentially expands or stretches to a selected or preferred diameter and can maintain that diameter even if a higher than expected pressure can occur.

[0042] The outer tubular element 200 in this embodiment is formed from polyurethane and has a wall thickness of about 0.003 inches. In this embodiment, the outer tubular element 200 has a relaxed inner diameter when first formed and before being assembled onto a catheter of about 0.100 inches when other components inside the outer tubular element are sized as described herein. This has an expected expanded inner diameter of 0.118 inches. The material is preferably wear resistant and highly resistant to puncture. The outer tubular element 200 in this embodiment is similar to a balloon catheter but has a structure without any folds or wrinkles and can be produced in a manner similar to the balloon blow molding process. In this embodiment, the outer tubular element 200 is formed prior to assembly so that it is configured to normally be crushed when incorporated into the catheter. Once installed, when the outer tubular member is expanded or inflated, the material of the outer tubular member is configured to produce an elastic rebound when the pressure is reduced or removed. The outer tubular member can be modified in several ways, but in this embodiment is configured to be uniform throughout its length. In other embodiments, the outer tubular member can be configured to have different properties at different locations along its length based on, for example, durometer, thickness, original or relaxed or recovered shape and / or diameter, material as well as thickness, and circumferential configuration. However, in this embodiment, the response of the outer tubular member to the expansion or inflation pressure from the internal fluid is relatively uniform throughout the outer tubular member and reaches a predetermined outer diameter that is maintained even at higher pressures until the pressure is removed and the outer tubular member contracts, retracts, or returns to its structural support elements. In this way, the expansion or inflation of the outer tubular element allows for engagement and disengagement of the layers without overstretching the outer tubular element. The outer tubular element can be configured to have a non-linear pressure versus diameter relationship such that the diameter of the outer tubular element can increase with pressure up to a predetermined diameter and then no further expansion occurs.

[0043] In this embodiment, the catheter tubular member 150 and the outer tubular element 200 form a nested tubular structure that is concentric, and together they define a cavity. Alternatively, they can be non-concentric and can have a geometry other than a cylindrical or circular cross-section.

[0044] The lumen structure and the tubular structure, including the tubular catheter 100, can provide rigidity to the lumen and the tubular structure, and in this embodiment, can also provide selectable or adjustable rigidity or flexibility to the lumen and the tubular structure, and can include a support structure, such as a central or intermediate support structure. The support structure can be disposed along the entire length of the lumen and the tubular structure, or at several locations along the length, and in this embodiment, the support structure is positioned adjacent to the distal end of the catheter. In one configuration of the support structure and the lumen or the tubular structure, the support structure can have an adjustable rigidity or a modifiable rigidity configuration, and the configuration can be affected by its geometry and how it is combined with the lumen or the tubular structure. In one configuration, the support structure is sandwiched or interposed between two structures, one or both of which can be adjustable relative to the support structure to vary the rigidity of the assembly. In that configuration or another configuration, the support structure has a surface that contacts one or more adjacent surfaces within or above the lumen or the tubular structure, and that contact results in a frictional force when the support structure bends or otherwise changes its configuration. The frictional force resists the configuration change and, for example, at least partially contributes to an increased rigidity or a decreased flexibility of the assembly in the region of the support structure.

[0045] The support structure can be composed of several configurations and, when placed over a lumen or tubular structure, the support structure can also be a tubular support structure. The support structure can take the form of a tubular mesh including a non-random mesh configuration, a tubular skeletal structure, a tubular framework, a tubular braid, a stent, such as a structure of a medical implantable stent, etc., and other structures. In the context of structural support elements, "non-random" as used herein includes elements between the ends of the structural support elements configured in a selected or controlled manner. For example, in some configurations where the support structure is a tubular mesh, skeletal structure, framework, or stent, the elements making up the support structure can have a relatively high degree of interconnectivity while still providing some degree of freedom of movement. However, in contrast to a stent, once the catheter is assembled, this support structure does not expand radially or substantially extend longitudinally, except for what may occur in response to the bending of the support structure and thus the catheter. In the technical field of stents, a relatively low degree of interconnectivity is referred to as an open cell configuration, and a relatively high degree of interconnectivity would be referred to as a closed cell configuration, or a configuration that tends towards a closed cell configuration more than an open cell configuration. A higher level of interconnectivity in a tubular mesh, skeletal structure, or framework may have more interconnectivity between elements than less interconnectivity between elements. Interconnectivity contributes to whether the support structure can move or change its geometry, and movement is easier with less interconnectivity and more difficult with more interconnectivity.

[0046] In addition to the inherent properties of the support structure that enable or resist a moving or changing geometric shape, the interaction of the support structure with adjacent surfaces also affects the resistance to a moving or changing geometric shape. For example, a larger contact surface area between the support structure and an adjacent surface creates a frictional force that resists movement or geometric shape change much more than a smaller contact surface area. A support structure that includes a number of components with surfaces that can contact an adjacent surface exhibits a higher resistance to geometric shape change or movement than one with fewer components, all other things being equal. Similarly, the surface properties of the components of the support structure can also affect the resistance to geometric shape change or movement. For example, surface texture or surface edges can contribute to a higher frictional force that can resist geometric shape change or movement when in contact with an adjacent surface.

[0047] Catheter 100 includes an intermediate or central support structure 300 (Figs. 2-9). In this embodiment, support structure 300 is a monolithic structure having a tubular shape formed of spurs, struts, or linear or curved rims 302 that are interconnected with an open space 303 therebetween to form support structure 300. Understanding that embodiments of support structure 300 are shown in Figs. 10-13 and are described in further detail therein, the cross-sections in Figs. 2-9 show cross-sections of elements of support structure 300 such that they do not correspond to the pitch of coil 158. The support structure is a three-dimensional configuration of spurs, struts, or linear or curved rims, and intermediate cavities or openings, the configuration of which can be selectively adjusted or changed and releasably fixed as desired. Adjacent structures can be selectively coupled and decoupled to provide support or tracking as desired. In this embodiment, three components are mechanically or frictionally decoupled to a greater or lesser extent to enable a selective change or adjustment in the configuration of the support structure, and then the three components can be recombined, for example, mechanically, with an increased contact surface area for frictional engagement.

[0048] In this embodiment, the support structure 300 is positioned intermediate the tubular member 150 and the outer tubular member 200 within a cavity or annular void 206 formed between the inner tubular member and the outer tubular member 200. Also in this embodiment, the support structure 300 extends substantially from the proximal end portion 202 to the distal end portion 204 of the outer tubular element 200, and the configuration of the support structure is substantially consistent over its length. However, the support structure can be configured to have different configurations depending on the axial and / or circumferential position. The support structure 300 can be secured to the outer surface 158 of the inner tubular member 150, for example, by stapling, adhesive, or other means at one or several end points such as at the proximal and distal ends of the support structure. Such securing can aid in assembly and can be removed prior to final assembly if desired. Conversely, the flexibility of the distal portion of the catheter can be reduced depending on the securing of the structural support 300 to the inner tubular member 150 axially and / or circumferentially. However, such reduction is generally not reversible and it can be difficult to reduce the reference flexibility or increase the stiffness of the distal portion of the catheter, or to increase the flexibility above the reference or reduce the stiffness.

[0049] The components of the structural support 300, such as the rim 302, can have several geometries. In this embodiment, each rim 302 has a substantially rectangular cross-section with a major axis parallel to the catheter's longitudinal axis and a minor axis perpendicular thereto. Aligning the major axes increases the surface area of each rim that can contact the adjacent surface 158 of the inner tubular member and the inner surface 208 of the outer tubular member 200. However, other geometries can also be used. In this embodiment, each rim 302 of the support structure 300 is shown in FIGS. 4 and 4A as being slightly outwardly spaced from the outer surface 158 of the inner tubular element 150. The support structure can be configured to have an inner diameter greater than the outer diameter of the outer surface 158 in the relaxed state, which can then create a limited surface contact between the structural support 300 and the inner tubular member 150 when first assembled. Alternatively, the support structure can be configured to have an inner diameter equal to or substantially the same as the outer diameter of the outer surface 158 in the relaxed state such that additional surface contact occurs between the structural support and the inner tubular member. In another alternative, the structural support 300 can be configured to have a smaller inner diameter in the relaxed state, for example, through an inherent bias in the support structure, to have a higher contact surface area with the inner tubular element in the relaxed state. The higher contact surface area promotes rigidity relative to the lower contact surface area between the support structure 300 and the inner tubular element 150.

[0050] As shown in FIG. 4, each rim 302 of the structural support 300 has a relatively defined set of corners or angular transitions 304 from one side surface to an adjacent side surface. The corners 304 are exaggerated in their sharpness, but the curvature of the transition between the surrounding surfaces of the rim can affect the frictional force that occurs through the contact between the rim and the adjacent surface, either with the outer surface 154 of the inner tubular element or with the inner surface 208 of the outer tubular element. The amount or degree and quality of the edge contact between the rim and their adjacent surfaces will more or less contribute to the rigidity or flexibility of the combination. All else being equal, a sharper or additional angular transition between the surfaces will produce a higher frictional force, and increased rigidity, or decreased flexibility. Thus, the non-circular rim profile on the structural support 300 can enhance the rigidity or reduce the flexibility of the distal portion of the catheter when the structural support contacts the adjacent surface. Similarly, the texture on the surface of the support structure that contacts the adjacent surface of the tubular element can also increase friction and rigidity or decreased flexibility. For example, a nitinol structural support 300 that is not electropolished may enhance the rigidity or reduce the flexibility of the distal portion of the catheter as a result of surface contact with the adjacent surfaces of the inner and / or outer tubular elements.

[0051] The structural support element can be formed from several materials, including stainless steel, nitinol, polymeric materials, and other suitable materials. The structure can have a smooth or angled cross-sectional geometry, can be finished or not finished, can be etched or not etched, can be polished or not polished (e.g., grit blasted), and can be electropolished or not electropolished using, for example, nitinol. The structural support element, such as a stent, will be configured to have the structure, material, and properties of such a stent for medical implantation, such as expansion.

[0052] The explanatory diagram of the catheter of FIGS. 1-9 shows a catheter shaft extending in a straight line in what is considered a neutral configuration. In such a configuration, as can be seen in FIG. 4, the outer surface 158 extends substantially linearly in the axial direction, and the adjacent surface of the rim 302 of the support structure 300 extends substantially parallel to the outer surface. In such a configuration, relatively little frictional engagement occurs between the corner 304 and the outer surface 154 until such time as the catheter bends. When the catheter bends, the concave portion of the bend may have a relatively high contact and frictional engagement with the adjacent rim corners 304, for example, at both corners of the rim, while in the convex portion of the bend, fewer corners 304 may contact the adjacent outer surface 154.

[0053] The outer tubular element 200 is relatively more flexible than the inner tubular element 150. In a configuration where the outer tubular element 200 is shrunk, compressed, or otherwise pressed against the support structure 300, the flexibility of the outer tubular element 200 allows the inner surface 208 to somewhat conform to the adjacent surface of the support structure. Specifically, the inner surface 208 extends over the rim 302 and curves or bends around the adjacent corner 304 with which it contacts. In addition, the outer tubular element 200 extends into the gap or space 210 between the adjacent rims of the support structure. As a result, any possible movement of the rim 302 to the left (or outwardly towards the outer tubular element 200) as viewed in FIG. 4A will tend to increase the frictional engagement between the corner 304 and the adjacent surface 208A and increase the resistance to movement of the rim. A similar effect occurs at those adjacent surfaces of the other rims and the outer tubular element, thereby accumulating forces that resist movement and also increasing the rigidity or decreasing the flexibility of that portion of the catheter. As a result of the bending of the catheter, any increase in frictional engagement between the rim of the structural support 300 and the adjacent surfaces of the outer tubular element 200 and / or the inner tubular element 150 will depend on the location and direction of the bend.

[0054] The resistance to bending or stiffness in the distal portion of the catheter can be reduced by reducing the amount of contact surface area between one or more rims 302 of the support structure 300 and one or more adjacent surfaces. The extent to which such contact can be reduced can depend on whether any one or more of the surfaces release or disengage from contact with the support structure and how many surfaces release or disengage from contact. In one configuration, the contact between the support structure and one or more adjacent surfaces can occur simply by moving the catheter such that the adjacent surface 154 of the inner tubular structure 150 and / or the adjacent surface 208 of the outer tubular structure 200 slide or glide over their respective rim surfaces. In another configuration, including those illustrated herein, one or both of the adjacent surfaces of the inner and outer tubular structures are separated from one or more respective surfaces of the support structure, thereby reducing or eliminating surface contact therebetween and thereby reducing or eliminating the contribution of these surfaces to resisting movement of the catheter.

[0055] In one embodiment (Figs. 5-6), the outer tubular element 200 can be released, detached, or separated from one or more adjacent surfaces of the support structure 300. For example, fluid within the syringe 108 can be injected into the lumen 134 of the inflation port and into the inner lumen of the catheter hub and catheter. As the pressure within the interior of the catheter rises, fluid flows through the aperture 164 into the annular cavity 206 between the inner and outer tubular members. The increase in pressure within the annular cavity causes the outer tubular element to expand or enlarge, and the inner wall 208 begins to move radially outwardly and disengages or mechanically and frictionally releases from contact with the adjacent surface of the structural support 300. The amount or degree of disengagement will be a function of the pressure and one or more locations of the aperture 164. In embodiments with non-compressible fluid and sufficient apertures 164 distributed along the cavity 206, substantially all of the outer tubular element will be released from the structural support 300 both circumferentially and longitudinally. When the whole or any part of the outer tubular element is released from the adjacent surface of the rim 302, the flexibility of the catheter in the region of the outer tubular element increases proportionally and the stiffness decreases proportionally. Conversely, as more portions of the outer tubular element contact the adjacent surface of the rim 302, the flexibility of the catheter in that region decreases proportionally and the stiffness increases proportionally.

[0056] In the embodiments illustrated in FIGS. 5-6 and other embodiments of this specification, variable stiffness is incorporated into a portion of the catheter. For example, when excess fluid is removed from the annular cavity 206 and the catheter lumen, such as by pulling out the plunger 112 on the syringe 108 or by applying a vacuum, etc., when the outer tubular element is in a relaxed state, that portion of the catheter has increased stiffness. Conversely, when the outer tubular element is expanded or inflated, such as by injecting fluid into the catheter lumen and cavity 206, that portion of the catheter has decreased stiffness. Thus, in the embodiments of this specification that use expansion and contraction, expansion and contraction can be used to affect the stiffness or flexibility of the tubular element. In this embodiment, expansion increases flexibility. Similarly, the relaxed or neutral state of the outer tubular element decreases flexibility and provides a more rigid structure. In addition, the ability to increase or decrease stiffness or flexibility depends in part on the structural member 300 enclosed in a capsule or case that is independent of the structure outside the outer tubular element and the structure inside the expander. The intermediate or central structural support 300 is sandwiched between opposing continuous surfaces, one or both of which are, for example, radially movable, such as where the outer tubular element 200 can expand radially outward with respect to the structural support 300.

[0057] In this embodiment, the outer tubular element wall is movable with the fluid pressure, outwardly with an increase in fluid pressure and inwardly with a decrease in fluid pressure. Increasing the fluid pressure separates, or widens, the spacing between each of the facing walls 208 and 154 of the outer and inner tubular elements. Decreasing the fluid pressure reduces the spacing between the facing walls of the outer and inner tubular elements and ultimately brings the outer tubular wall into contact with one or more rims of the structural support 300. When the pressure is removed, the outer tubular element applies pressure to the structural support 300, squeezing the structural support between the outer and inner tubular elements, thereby changing the mechanical properties, stiffness, and flexibility of that portion of the catheter. When fluid is used to expand the outer tubular element, it can be seen that the structural support 300 is within a closed fluid system and within a cavity that is closed except for fluid communication with a fluid source for the fluid pressure. Having a support structure within an enclosed cavity within the catheter provides further predictability to the controllability of the stiffness or flexibility of the catheter. Additionally, when the outer tubular element is formed from a material and configured according to the assembly to be elastically biased in the direction of the structural support member, the elasticity of the outer tubular element serves to maintain the clamping or application of pressure on the support structure when the pressure is reduced or removed. The flexibility of the catheter can be adjusted by changing how the structural support element 300 is captured between the layers of the outer tubular element 200 and the inner tubular element 150 or concentric tubular elements. The flexibility can be adjusted by manipulating the fluid within the fluid system of the catheter lumen and cavity 206, and the fluid can be used to separate or increase the spacing between the concentric tubular elements. For example, a similar effect can be achieved by reducing the fluid pressure within the cavity such that the outer tubular element has a relaxed or unbiased configuration and has little or no contact with the support structure. By reducing the pressure within the cavity 206, the outer tubular element can be brought into further contact with a greater surface area of the structural support, thereby increasing the contact surface area and the rigidity or stiffness of that portion of the catheter.Alternatively, the outer tubular element is configured to press against the structural support element in its neutral or relaxed state, e.g., in the relaxed state, the outer tubular element has an inner diameter less than the outer diameter of the structural support element. In the embodiments illustrated herein, the neutral configuration of the assembly causes the outer tubular element to press against the structural support element when there is no elevated fluid pressure within cavity 206. Additionally, the assembly can be configured such that the fluid pressure naturally reduces when an active pressure is not being applied to syringe 112 by the user.

[0058] The catheter assembly is used such that the catheter 100 can be positioned, e.g., at a desired location within the vasculature, such as by using a guide device to direct the catheter to the desired location and position. For example, a guide wire (not shown) extends into the central lumen of the dilator and is directed into the appropriate vasculature, and the dilator and catheter with the expanded or enlarged outer tubular element are passed along the guide wire until positioned as desired. Once in place, the outer tubular element is contracted or reduced to fix the catheter geometry in place. The dilator 122 is then removed, and the remaining catheter with the fixed adjustable flexible element remains in place for subsequent procedures. As shown in FIG. 7, the dilator has been removed and the syringe 108 has been removed from the injection port 106. The catheter is then ready to receive an intervention device, material, or other component through the catheter hub 104. When the procedure is complete, fluid is reintroduced into the lumen with either the intervention device or dilator in place, the syringe attached to the injection port 106, and the outer tubular element 200 inflated to allow removal of the catheter 100.

[0059] In an alternative embodiment of the catheter (Figs. 8-9), catheter 100A has an outer tubular element 200 that encloses a structural support 300 and has the structure and functionality described above with respect to the embodiments of Figs. 1-7, except as discussed herein. In this embodiment, catheter 100A includes a catheter shaft 102A that is identical to catheter shaft 102, except that the opening 164 is omitted, the proximal portion of the catheter shaft extends further into catheter hub 104A beyond the opening of injection port 106, and except for one or more inflation lumens 170. The structure, geometry, and dimensions of exemplary catheter shaft 102A are substantially the same as those of catheter shaft 102, except that the catheter shaft includes an inflation lumen 170 defined by an inner wall 172 that extends from inflation lumen 134 within catheter hub 104A to the proximal portion 202A of the outer tubular element 200. The inflation lumen 170 has an internal lumen configured to allow for the desired inflation of the outer tubular element, enabling the catheter to be used without using a dilator to expand or enlarge the outer tubular element 200. The proximal portion 202A is sealed around the distal portion of the catheter shaft and inflation lumen 170 and withstands any fluid pressure expected within the lumen and cavity 206 of the outer tubular element. The proximal portion of the catheter is supported and sealed within catheter hub 104A as would be done with a conventional catheter. A catheter is shown in Fig. 8 that contracts or crushes the outer tubular element 200, presses on the structural support 300, and clamps or compresses the structural support 300 between the outer and inner tubular elements. Injecting fluid into lumen 170 and increasing the pressure within the fluid system from injection port 106 through lumen 170 into cavity 206 within outer tubular element 200 expands or inflates the outer tubular element 200, such that the pressure is no longer applied to a portion of, or in the illustrated embodiment, the entire structural support element 300, and reduces the stiffness and increases the flexibility of that portion of the catheter (Fig. 9).

[0060] The structural support element 300 in this embodiment includes a repeating pattern (Figs. 10 - 13). Fig. 10 shows the structural support element 300 extending along and around adjacent portions of the inner tubular element 150 from a first end 306 to a second end 308. Since the structural support element is formed from a tubular mesh design, the first and second end portions are terminations of the pattern therebetween and are not terminated with extra structure added to end portions that do not exist in the internal pattern.

[0061] A structural support element having a repeating pattern can have the repeating pattern isolated into repeating groups or cells, but it is understood that a structural support element having no recognizable repeating pattern will have a more complex structure that may not be suitable for identification of repeating groups or cells. This support structure 300 (Fig. 12) repeats circumferentially to provide six cells in this embodiment, and repeats longitudinally to provide, in the embodiment illustrated in Fig. 10, a structure with eleven cells of a terminal boundary that matches approximately half a cell added to the cells 310, depending on how the support structure is generated. Since the support structure is one used in a catheter in this embodiment, it is desirable to exclude any free end rims 302. In the illustrated embodiment, each rim terminates at both ends in one or more other rims respectively.

[0062] In the structural support element 300, each cell 310 includes a first strut 312 that, in this configuration, is a longitudinally extending strut that extends longitudinally in the tubular support structure and parallel to the axis of the inner tubular member 150. As shown in Fig. 10, the support structure and the tubular inner element 150 are concentric and coaxial over the length of the structural support element 300. The cell 310 also includes portions of adjacent longitudinal struts 312A and 312B. The longitudinal struts 312 extend parallel to each other and are circumferentially distributed around the tubular support structure. In this configuration, the longitudinal struts 312 are offset both circumferentially and axially with respect to adjacent longitudinal struts 312A and 312B.

[0063] Each vertical strut includes a first end 314 and a second end 316. The first and second ends are each joined or coupled to a series of serpentine struts extending from opposite sides of the vertical strut. The first end 314 of the vertical strut is joined or coupled to a first serpentine strut 318 on one side of the vertical strut and from the first serpentine strut 318 to a second serpentine strut 320 on the opposite side of the vertical strut. The first end 314 of the vertical strut forms a node point where three struts are joined or converge. Similarly, the second end 316 of the vertical strut 312 is joined or coupled to a third serpentine strut 322 on one side of the vertical strut, which is the same side as the first serpentine strut 318, and from the first and third serpentine struts 318 and 322 to a fourth serpentine strut 324 on the opposite side of the vertical strut. The first and second serpentine struts extend away from the vertical strut 314 and towards the third and fourth serpentine struts, which also extend away from the vertical strut 314 and towards the first and second serpentine struts, respectively.

[0064] The opposite ends of the second and fourth serpentine struts are joined or coupled at their respective ends to respective vertical struts 312B and 312A, the ends of which form respective nodal points. The second serpentine strut 320 is joined or coupled to the second end 328 of the adjacent vertical strut 312B, and the fourth serpentine strut 324 is joined or coupled to the first end 330 of the adjacent vertical strut 312A. The fifth serpentine strut 332 is coupled to the second end of the vertical strut 312B and to the first end of the vertical strut 312'. The sixth serpentine strut 334 is coupled to the first end 330 of the vertical strut 312A and to the second end of the vertical strut 312'. Thus, in this configuration, the cell 310 includes two vertical struts, as the contour lines formed from a complete vertical strut and two halves are drawn, and the cell includes four serpentine struts formed from a total of two complete serpentine struts and four partial serpentine struts. Each cell includes four nodal points, and each nodal point is a junction of three struts. As can be seen in the illustrated embodiment, all struts are joined or coupled to at least two other struts, the vertical struts are coupled to four serpentine struts, and each serpentine strut is coupled to two vertical struts. This arrangement provides a moderate degree of interconnectivity, allows for free-form radial expansion and contraction (before the support structure is combined with any other structure), and allows for free-form vertical expansion and contraction. The amount of expansion and contraction is determined in part by the starting angle of the angle 336 when the support structure is first formed. For example, when the support structure is first formed at a relatively small angle 336, a larger radial expansion than radial contraction is permitted because the starting angle is small. Conversely, when the first support structure is first formed at a relatively large angle, the remaining radial expansion is less and the available radial contraction is greater than for a relatively small angle 336.

[0065] The structural support member 300 in any given cross-section is configured to have at least two struts in the cross-section, and in many designs, there will be at least three struts since three points define a plane. In the exemplary structural support member 300, the cross-section will intersect at least six struts 312 (FIG. 11A). The six longitudinal struts 312 are substantially uniformly distributed around the circular support member 300. Such a cross-section can be visualized in FIG. 12 on either one of the sides of the cell 310 (as visualized in FIG. 12). However, in other cross-sections along the axial direction of the structural support member, additional struts become visible. For example, 12 struts will be visible when the cross-section intersects a nodal point such as 328, and 24 struts will be visible when the cross-section intersects the middle portion of the serpentine struts. Additionally, as would be seen in the cross-section, the longitudinal struts are of a different size than the serpentine struts and have a larger cross-sectional area. There are more smaller struts than there are larger struts, and in this embodiment, there are more than twice as many smaller struts as there are larger struts in a given cell. Also, as can be seen in FIG. 12, all of the struts are connected and are interconnected or interconnected such that in this embodiment, each strut is connected to at least two other struts. Also, as can be seen in FIGS. 10 and 12, no single longitudinal strut extends the entire length of the structural support member without a bend or transition to another longitudinal strut. Additionally, in the illustrated embodiment, no single element of the structural support member, nor in this embodiment, no single strut, extends the entire length of the structural support member without a bend or transition to another element / strut.

[0066] In this embodiment of the support structure, the support structure is formed from a solid tubular element having a constant wall thickness (thereby providing a substantially constant thickness to all of the struts) and is laser cut in a manner similar to the formation of a stent so as to form the tubular mesh shown in FIGS. 10 or 16 and 17. In an embodiment of the support structure 300, the angle 336 formed during the formation of the support structure may be a small acute angle, for example, as small as a few degrees (1-2°), or a large acute angle, for example, as large as 85-89°. Larger angles (obtuse angles) are also possible and provide a structural support, but once incorporated into the catheter assembly, do not provide the same structural support as the configuration of the support structure 300 having the acute angle 336 when first formed.

[0067] In the configuration of the structural support generated using the pattern shown in FIG. 12, the angle 336 is selected to be approximately 8°. In the final assembled configuration of the structural support shown in FIG. 10, the angle represented by 336 is approximately 24° after the support structure is expanded.

[0068] The support structure 300 in this embodiment is formed from a solid tubular element having a wall thickness of 0.003 inches. The structural support 300 is then laser cut in a manner similar to that used to form a stent such that all of the struts have a thickness 338 equal to the starting wall thickness of the solid tubular element. In this embodiment, the width 340 of the longitudinal struts is about 0.004 inches (in this embodiment, about 0.002 inches and approximately twice as large as the width 346 of the serpentine struts which exceeds the thickness), while the thickness is about 0.003 inches (exceeding the width 346 of the serpentine struts). As a result, the longitudinal struts are more resistant to bending than the serpentine struts. The cell geometry, strut wall thickness, strut width, and angle 336 contribute to the rigidity, flexibility, or resistance to bending of the support structure in a free form separated or spaced from the catheter assembly. Such rigidity, flexibility, or resistance to bending of the support structure is carried over to the assembly within the catheter and will exhibit similar characteristics in the catheter assembly. The strut thickness and width can be selected to be from about 0.0005 inches to 0.0100 inches. Additionally, the rigidity, flexibility, or resistance to bending of the catheter assembly in the region of the support structure 300 is determined in part by the engagement and interaction of the components of the assembly with each other, including the rigidity, flexibility, or resistance to bending of the support structure itself and the contact surface area between the structural support and the adjacent surface. When such contact surface area is reduced or removed, such as by the expansion or dilation of the outer tubular element, the various contributions to rigidity, flexibility, or resistance to bending are reduced, but the inherent rigidity, flexibility, or resistance to bending of the support structure itself remains. Thus, the design or pattern of the support structure determines not only the rigidity, flexibility, or resistance to bending of the support structure itself, but also its contribution to the rigidity, flexibility, or resistance to bending of the catheter based on the interaction of the support structure with adjacent components. In the configuration illustrated and described in FIGS. 10 - 13, the structural support member has cells with surfaces facing the outer tubular member, each cell having a facing surface area of about 0.00075824 inches, and similarly, with surfaces of each cell facing the inner tubular member.

[0069] The effect of the interaction between the support structure 300 and any adjacent component is, in part, affected by the radial position of the support structure. There is a flexible inner tubular member 150 having an inner radius R1 from the center and an outer radius R2 from the center, and the support structure 300 will be on or in close proximity to the outer surface 154 of the inner tubular element. In this embodiment, the inner diameter of the support structure 300 is represented by a radius R3 from the center that is substantially equal to the radius R2 such that the support structure contacts the outer surface 154 of the inner tubular member. The outer radius R4 of the support structure 300 is then determined by the wall thickness of the support structure. Additionally, the inner diameter of the outer tubular member 200 is represented by a radius R5 from the center and the outer diameter is represented by a radius R6, both determined while the outer tubular element is expanded or distended or inflated. The maximum inner diameter of the outer tubular element in a relaxed or crushed state substantially corresponds to R4, i.e., the outer diameter of the support structure, and the maximum outer diameter of the outer tubular element in a relaxed or crushed state is substantially the outer diameter of the support structure plus the wall thickness of the outer tubular element. The minimum inner diameter of the outer tubular element when in a crushed or non-expanded state will depend on the flexibility of the material of the outer tubular element and the relative surface area of the open area between the struts that will allow the material of the outer tubular element to extend between the struts. The radius values of the structural support 300 are set forth in Table I below.

Table 1

[0070] The resistance to bending in a tubular structure such as a catheter generally occurs on the outer surface of the tubular structure. As shown in FIG. 11A, the support structure and the outer tubular element are positioned at a distance outside the assembly, and the mechanism in the form of a structural support, which is used to provide variable stiffness in this embodiment, is located, for example, in or on the region of the outer surface of the inner tubular member where the mechanical properties of the structural support can have a strong influence. As shown in FIG. 11A, the structural support is in the region of about 95% of the maximum outer diameter of the catheter. Thus, for example, by applying it to the outer region of the catheter with respect to the central axis, which is 50% to 100% of the overall outer diameter of that part of the catheter, it is the influence of the structural support on the flexibility or rigidity of the part of the catheter where it is disposed. In addition, the function of the contact surface area, such as between the structural support and the outer surface 154 of the inner tubular member 150 and / or between the structural support 300 and the outer tubular element 200, can be improved by positioning the structural support elements at a higher radial position than a lower radial position because the available surface area increases with the square of the radius. Thus, disposing the structural support elements outside the inner tubular element 150 enhances the contribution of the contact surface area and frictional resistance generated between the structural support and any adjacent surface.

[0071] FIG. 14 shows a part of the structural support 300 in a substantially neutral state. For example, after being assembled on the inner tubular element and formed in the catheter assembly, it is in a usable state, but after a certain residual movement, since not all of the longitudinal struts 312 are precisely parallel, the serpentine struts generally labeled 348 adapt accordingly. The longitudinal struts are not under compression or tension and are substantially regularly spaced from each other, and the serpentine struts 348 are also not under tension or compression, but such a state will depend on the initial scale of the angle 336 (FIG. 12) when the support structure was first generated and its state when positioned on the inner tubular element.

[0072] Due to their relatively small thickness and width, the struts freely bend relative to each other with a minimal applied force when in an unconstrained state, such as when the outer tubular element 200 is expanded or inflated. When the structural member 300 is bent in its unconstrained state based on the applied bending load, the struts rearrange themselves to adapt to the changed mechanical state, as schematically represented in FIG. 15. In FIG. 15, the longitudinal and serpentine struts rearrange themselves to the lowest energy configuration available with the imposed curvature while maintaining the length and interconnectivity of the struts. In the concave portion of the support structure, the longitudinal struts are brought closer together, and their approach is limited by the serpentine struts that are put under tension, and the angle 336 becomes more acute. The acute angle between adjacent longitudinal and serpentine struts aids in the force transmission between the longitudinal struts when they rearrange themselves. On the convex side of the bend, the longitudinal struts tend to separate in some regions under the constraints of the attached serpentine struts and adjacent longitudinal struts.

[0073] When the support structure is incorporated into a catheter as described herein, the rearrangement of the struts occurs with a relatively low force, as required in a tracking mode when the structural support elements are unconstrained or when the outer tubular element is expanded, inflated, or separated from the structural support elements. The rearrangement of the struts either does not occur or occurs with a much higher force applied compared to when in an unconstrained state when the structural support is constrained, such as when the outer tubular element is crushed or when pressing on the structural support elements, i.e., when the catheter is in a support mode. The relatively high degree of interconnectivity between the struts allows for the flexibility of the support structure to bend, but the interconnecting points between the struts limit the degrees of freedom by which the struts can rearrange themselves. These factors can be varied by increasing or decreasing the number of nodes per unit length, increasing or decreasing the number of struts at a node, separating the struts into groups of struts and connecting one group of struts with more nodes and another group of struts with fewer nodes, and similar variations.

[0074] In one exemplary catheter configuration, the length of the catheter distal from the catheter hub is about 36 inches or about 90 cm, and the length of the variable flexibility portion with the support structure 300 and the outer tubular element 200 is about 8 inches or 20 cm. The portion of the catheter shaft that can include the variable flexibility portion can be larger or smaller than in this example.

[0075] The structural support element can be configured in several ways, particularly in view of the number of stent configurations being developed. As one example of an alternative structural support element (FIG. 16), the support element 400 includes cells 402 that form the basis of a repeating pattern extending in the longitudinal and circumferential directions. The cells 402 form part of a helical pattern that includes a rectangular frame 404, where the cells have four sides and define an opening 406. Each cell is separated from adjacent cells longitudinally by laser cut separation to form a helically wound ribbon. The opening 406 serves to receive the flexible portion of the outer tubular element when it is crushed or pressed against the structural support element, thereby helping to limit or restrict movement by mechanical engagement or frictional resistance. In an alternative configuration, the cells 402 can be connected together, as shown in FIG. 16 for example, or connected by one or more knot points (not shown) that provide additional flexibility between circumferentially adjacent cells, and can form a non-helical configuration with two or more circumferentially adjacent cells. Adjacent cells longitudinally can also be connected by one or more knot points (not shown) depending on the desired flexibility in the constrained and unconstrained states.

[0076] In another example of the structural support element (FIG. 17), the structural support element 410 is formed from a helically cut tube or a helically wound ribbon. The structural support element includes longitudinally extending protrusions 412 within one portion of the winding that extends into complementary longitudinally extending cavities 414 within adjacent windings. Windows or openings (not shown) may be provided within the edge surfaces of the helical windings to provide a friction engagement surface with the outer tubular element.

[0077] Adjustment of the flexibility or stiffness of part of the catheter 100 / 100A is used to provide a structural support within the blood vessel when desired, either to allow the catheter to follow a path within the blood vessel, for example, via a guide wire or other guiding device, or alternatively to assist passage of an intervention device or the like. In the tracking mode, the inner tubular member is flexible for easy tracking ability, resistant to kinking to minimize damage during use, and provides suitable force transmission along the long axis of the catheter for pushing and advancing through the blood vessel. In the tracking mode, the structural support elements are flexible and when unrestrained, the struts of the structural support elements bend freely, adapt and realign, and move freely in response to the positioning of adjacent struts. The struts align to the lowest energy configuration possible. When the catheter is positioned as desired, the structural support elements are compressed between the outer tubular element and the inner tubular element, thereby being restrained and the struts no longer move freely relative to each other or relative to adjacent surfaces without a significant amount of force. In the restraint or support configuration, the structural support resists bending of the catheter, reducing its flexibility and increasing its stiffness. This configuration is similar to a clutch, thereby allowing free movement of the structural support elements and the struts therein such that disengaging the outer tubular element from the structural support element and further from the inner tubular element can be limited by the bending limitation of the structural support element itself. Applying a vacuum or negative pressure, or removing inflation fluid from the inside of the outer tubular element, engages a clutch structure that mechanically couples the outer tubular element, the structural support element, and the inner tubular element, making the catheter structure in the region of the structural support element less flexible and better supporting a device that can be passed through the catheter lumen.

[0078] During operation, the fully assembled catheter assembly 100 / 100A is placed in a tracking configuration by injecting fluid into the cavity 206 within the outer tubular element 200 or otherwise increasing the pressure within the cavity. The tubular element is expanded or enlarged such that the outer tubular element is released from or mechanically disengaged from the structural support element 300, thereby reducing or eliminating the frictional resistance to bending with the structural support element 300. The pressure is maintained within the cavity 206 or the outer tubular element is otherwise maintained in an expanded or enlarged configuration. The catheter assembly is introduced into a body lumen, for example, through a trocar, introducer, or other structure and is moved through the vasculature 500 (Figs. 18 - 20), for example, using a guidewire 502. When the guidewire 502 is moved to a new position as shown in Fig. 18, the catheter 100 / 100A is advanced via the guidewire in a catheter tracking mode. When the catheter reaches a desired location as shown in Fig. 19, the catheter assembly can be placed in a support mode by withdrawing fluid or applying a negative pressure to the lumen in fluid communication with the cavity 206 or by allowing the rebound or memory of the expanded outer tubular element 200 to return towards its relaxed state, contracting to mechanically engage or contact the structural support element, applying pressure to the structural support element, and crimping the structural support element between the outer and inner tubular elements. The flexible wall of the outer tubular element also bulges into the openings 303 between the struts of the structural support element 300 (possibly contacting the outer surface 154 of the inner tubular element), thereby increasing the mechanical engagement or frictional force that resists movement of the structural member relative to the adjacent surface, thereby increasing the stiffness and support of the catheter assembly. Reinforcements, such as coils 158 within the inner tubular element, resist deformation of the inner tubular member, either alone or in combination with any bending load, for example, due to any compressive load from the outer tubular member. In the embodiments herein, the inner tubular element is substantially non - compressible with respect to the pressure loads that would be experienced under normal operating conditions.Next, the guidewire can be replaced by an intervention or other device 504 (Figure 20) which may also have its own structural support elements and a flexible outer tubular element for adjustable support as it is withdrawn and the desired procedure is performed. Next, the catheter assembly can be withdrawn after returning the catheter assembly to the tracking mode, which may include the step of reinserting the dilator, and then withdrawn according to conventional methods.

[0079] Before the catheter is introduced into the lumen and as the catheter passes through a body lumen as depicted in FIG. 18, the catheter can be in a tracking or flexible mode within the region of the structural support member. In that configuration, the catheter can assume several shaped configurations. For example, after manufacture, the catheter can be straight and include a variable stiffness region within the region of the structural support member. While the catheter is passing through the body lumen, the catheter including the variable stiffness region will assume a shaped configuration that conforms to the body lumen. In these shaped configurations, while the structural support member is released or freely adjusting its shape, the structural support member can have several configurations. One configuration is illustrated in FIG. 15 where the struts are rearranging themselves into the lowest energy configuration imposed on them by the wall of the inner tubular member. However, when a part or all of the structural support member assumes a fixed shaped configuration, for example, by being clamped, compressed, or squeezed between an inner tubular element and an outer tubular element, the structural support member and the surrounding catheter structure maintain a fixed shaped configuration that is also the configuration of the surrounding lumen wall. As a result, the variable shaped portion of the catheter adopts the shape of the surrounding lumen and does not substantially change its shape until released. For example, once the catheter is positioned as desired while in a tracking, flexible, or released mode as in FIG. 19, the variable shaped portion of the catheter assumes a second shaped configuration that is different from the previous shaped configuration while the catheter was passing through the lumen. When the structural support element is clamped, laminated, or fixed in the second shaped configuration, the variable shaped portion of the catheter applies only a very small force 506 or pressure to the lumen wall, if any, as a result of the transition from the tracking or flexible mode to the support or fixed mode in the second shaped configuration. If the catheter could theoretically be lifted out of the body lumen without having to pass through the lumen passage again, it will be seen that the catheter maintains the shape of the lumen it adopted as if it had shape memory. In other words, the variable shaped portion of the catheter when transitioning from the tracking or flexible mode to the support or fixed mode applies only a very small force, if any, to the adjacent lumen wall.Such results can be illustrated by a three-point bending test using the variable shape portion of a catheter arranged in a second shape configuration, and the forces measured before and after fixing or compressing the structural support member will not be very different. For example, the difference in force can be about 20% - 25%, can be within the range of 15 - 25%, and can be less than 10% when using the configuration of the structural support member 300 illustrated in FIGS. 10 - 13 (the force after fixing or compressing the structural support member minus the force before fixing or compressing the structural support member, divided by the force before).

[0080] The difference between the tracking mode and the support mode can be illustrated by comparing the forces used to deflect a linear catheter assembly in the variable stiffness region. Using a substantially linear catheter, the middle portion or other selected portion of the variable stiffness region can be bent to 1 inch or other selected distance by applying a normal force and measuring the force required to move the selected distance. The force is measured when the catheter is in the tracking mode or a more flexible state, and when the catheter is in the support mode or a more rigid or stiff and less flexible state. In one embodiment where the outer tubular element is completely separated from the underlying structural support member and the catheter is bent 1 inch, the measured force is about 0.38 pounds force (lbf.). The catheter is then returned to a linear configuration and placed in the support mode, or the outer tubular member is pressed against the structural support member and bent 1 inch. The measured force is about 0.54 pounds force. The bending force ratio of the support mode force divided by the tracking mode force in this embodiment is about 1.42. A ratio greater than 1 provides a desirable catheter configuration, and a ratio of about 1.2 and greater is more desirable.

[0081] The catheter assembly can be assembled in several ways, including in part by conventional methods for assembling a catheter. In one method (Figs. 21-28), a mandrel assembly 600, similar to conventional assembly devices, is used. The mandrel assembly is selected to have a mandrel 602 to provide a catheter of a desired size with a selected inner diameter. In one process, the inner tubular member 150 is assembled by sliding a polytetrafluoroethylene liner over the mandrel 602 and applying braiding or coil reinforcement over the liner. Extrusion is applied over the braiding or coil reinforcement, and then the layers are firmly laminated inside a removable heat shrink tube so that all of the components are incorporated together onto the inner tubular member 150. One or more holes or openings 164 are formed in the laminate and extend completely therethrough in the region where the structural support elements will be located. The structural support elements are formed, for example, by focusing a laser to cut a monolithic metal tube according to a desired pattern. The structural support element 300 is disposed over the tubular member 150 and positioned as desired. This may be crimped and adhered at its distal and proximal ends so as to secure it to the inner tubular member for assembly.

[0082] Next, a mandrel with an inner tubular member assembly is inserted into a tubular loading tool 604 (Figs. 23-26) with a structural support element within a barrel 606 of the loading tool. The barrel 606 can include a plurality of parts that are separated, for example, to insert the mandrel and the inner tubular member. The loading tool includes an O-ring seal 608 at the distal portion to provide an airtight seal around the inner tubular member and the mandrel. The loading tool 604 also includes a pressurizing port 610 proximal to the seal 608 to provide pressurized air or other pressurized fluid around the outside of the inner tubular element extending toward the distal end of the tubular element. The barrel 606 includes an annular hole edge or ridge 612 at the distal end to receive one end of an expandable tubular element 614 that is sealed around the barrel using an O-ring seal or other seal element 616. The parts of the barrel can be separated, the proximal portion can be disposed to cover the proximal portions of the mandrel and the inner tubular element, the distal portion can be disposed to cover the structural support element, and the two parts can be joined and sealed. The expandable tubular element 614 is applied to the distal portion of the barrel and can be sealed using the seal 616. As shown in Fig. 23, the relaxed state of the expandable tubular element 614 is less than the outer diameter of the structural support element 300, and Fig. 23 schematically shows the relationship and a larger spacing between the expandable tubular element and the mandrel 602 for ease of illustration. The opposite end of the expandable tubular element is closed, for example, using a closure knot, clip, ligation, or the like. Next, an inflation pressure, for example, about 40 psi and perhaps as high as 80 - 100 PSI, is applied at the inflation port 610 to inflate the expandable member 614 as shown in Fig. 24. The applied pressure expands or dilates the expandable member in the diametrical direction. When the expandable member is stabilized, the mandrel and the inner tubular member assembly are slid inside the outer tubular element 614 such that the expandable member is suitably positioned covering the structural support member and the underlying assembly (Fig. 25). Next, the pressure is removed from the expandable member, for example, through the pressurizing port, and the expandable member crushes around the adjacent portions of the structural support member and the inner tubular member (Fig. 26).Next, the assembly is removed from the loading tool 604 (FIG. 27), and the expandable member is cut to a desired length around the structural support member. Next, the outer tubular element 200 is adhered to the inner tubular element at 618 and 622 and further cut if necessary (FIG. 28). Next, the mandrel 602 is replaced by a smaller mandrel 622, and the tip of the catheter is joined by reflow to reduce its diameter to that of the smaller mandrel to provide a desired interference fit with the appropriate dilator tip. Next, the mandrel 622 is removed, and the tubular assembly is adhered or otherwise secured at its proximal end to a proximal hub, such as catheter hub 104 (FIGS. 1-2).

[0083] By selection of a suitable material for the outer tubular element 200, for example, by using a relaxed tubular member having an inner diameter that, in a relaxed state, is less than the structural support member and perhaps even less than the inner tubular element, elasticity or pressure memory can be incorporated into the outer tubular member in response to assembly. Expansion of the expandable material allows for easy assembly of the outer tubular element onto the catheter assembly to provide the desired elasticity such that the outer tubular member can apply an appropriate pressure to the structural support element.

[0084] Thus, while several exemplary implementations have been described, it will be apparent that various modifications and alterations can be made without departing from the concepts discussed herein. Such modifications and alterations are aimed at and suggested to be within the spirit and scope of the invention even though they are not explicitly described above. Accordingly, the foregoing description is intended to be illustrative only.

Claims

1. A catheter for use within a blood vessel, the catheter comprising: a hub having an injection port; a flexible shaft extending from a proximal portion attached to the hub to a distal portion, the flexible shaft comprising: a tubular wall; a shaft support member within the tubular wall; a flexible shaft comprising: a balloon mounted on a portion of the tubular wall covering the distal portion of the flexible shaft so as to form an enclosed cavity closed at the distal end of the balloon; an inflation lumen extending from the injection port into an interior space of the cavity of the balloon; an outer support member surrounding the tubular wall within the cavity formed by the balloon, the outer support member comprising a tubular monolithic structure having a plurality of nodes with a plurality of struts, the plurality of struts being joined to each respective one of the plurality of nodes; a catheter, wherein the balloon is configured to change from an inflated configuration in which the distal portion of the flexible shaft has a first amount of rigidity to a deflated configuration in which the balloon conforms to the shape of the outer support member, thereby imparting a second amount of rigidity greater than the first amount to the distal portion of the flexible shaft.

2. The catheter of claim 1, wherein the shaft support member comprises a single continuous helical coil.

3. The catheter according to any one of claims 1 to 2, wherein the shaft support member provides sufficient support to make the tubular wall non-compressible during use.

4. The catheter according to any one of claims 1 to 3, wherein the tubular wall has a thickness between 0.003 inches and 0.020 inches and an inner diameter between 0.025 inches and 0.100 inches.

5. The catheter according to any one of claims 1 to 4, wherein the balloon is made of polyurethane and has a wall thickness of 0.003 inches.

6. The catheter according to any one of claims 1 to 5, wherein the outer support member is attached to an outer surface of the tubular wall.

7. The catheter according to any one of claims 1 to 5, wherein the outer support member is not attached to either the outer surface of the tubular wall or the inner surface of the balloon.

8. The balloon lumen according to any one of claims 1 to 7, wherein the balloon lumen includes an inflation tube attached to the outer surface of the tubular wall between the injection port and the internal space of the balloon.

9. The balloon lumen according to any one of claims 1 to 7, wherein the balloon lumen is formed within the tubular wall between the injection port and the internal space of the balloon.

10. The balloon lumen according to any one of claims 1 to 7, wherein the balloon lumen comprises a central lumen formed by the tubular wall.

11. The catheter according to any one of claims 1 to 10, further comprising a dilator shaft extending through a central lumen formed by the tubular wall, wherein a distal tip of the dilator shaft forms a seal with a distal end of the tubular wall, and the balloon lumen is in fluid communication with a space between an outer surface of the dilator shaft and an inner surface of the tubular wall.

12. The plurality of struts of the outer support member are a plurality of longitudinal struts arranged parallel to each other circumferentially along the length of the outer support member, each longitudinal strut having a first end and a second end, and a plurality of serpentine struts attached to the plurality of longitudinal struts, each of the plurality of serpentine struts being attached at one end to the first end of one of the plurality of longitudinal struts and at the opposite end to the second end of a second longitudinal strut among the plurality of longitudinal struts. The catheter according to any one of claims 1 to 11, comprising

13. The catheter according to claim 12, wherein each longitudinal strut is arranged with other longitudinal struts in one of the plurality of circumferential rows, and each longitudinal strut has, above it, two longitudinally offset longitudinal struts from two adjacent rows among the plurality of rows, and, below it, two longitudinally offset longitudinal struts from the two adjacent rows.

14. The catheter according to claim 13, wherein each of the plurality of rows includes a plurality of full longitudinal struts and a plurality of half longitudinal struts.

15. Each of the plurality of longitudinal struts forms two of the plurality of nodes, the two being a first node, wherein the first end is attached to a first serpentine strut and a second serpentine strut among the plurality of serpentine struts. A second nodal point, wherein the second end portion is attached to a third serpentine strut and a fourth serpentine strut among the plurality of serpentine struts, the second nodal point The catheter according to claim 12, comprising:

16. The catheter according to claim 15, wherein the outer support member is woven into cells, and each cell includes four nodal points among the plurality of nodal points.

17. The catheter according to claim 12, wherein the outer support member has a wall thickness between the width of the plurality of longitudinal struts and the width of the plurality of serpentine struts.

18. The catheter according to claim 12, wherein the wall thickness of the outer support member is 0.003 inches, each of the plurality of longitudinal struts has a width of 0.004 inches, and each of the plurality of serpentine struts has a width of 0.002 inches.

19. The catheter according to any one of claims 1 to 18, wherein the shaft support member and the outer support member are made of a material selected from the group consisting of stainless steel, nitinol, and polymer.

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