Balloon catheter and support shaft for same

ES 2 807 348 T3

DESCRIPTION

Balloon catheter and support shaft for it

Field

[0001] The invention relates generally to medical devices; more particularly, to balloon catheters and balloon catheter support shafts. Methods of manufacturing such devices are also described.

Background

[0002] The use of intravascular medical devices has become an effective method for treating many types of vascular diseases. In general, a suitable intravascular device is inserted into the patient's vascular system and directed through the vasculature to a desired target site. Using this method, virtually any target site in the patient's vascular system can be accessed, including the coronary, cerebral, and peripheral vasculature.

[0003] Catheters are often used to place medical devices such as stents and embolic devices at a desired location in the body. A medical prosthesis, such as a stent for example, can be loaded onto a catheter in a configuration that has a reduced diameter and can then be inserted into the lumen of a vessel in the body. Once brought to a target location in the body, the stent can then be expanded to an enlarged configuration in the vessel to support and reinforce the vessel wall while maintaining the vessel in an open, unobstructed condition. The stent can be configured to be self-expanding, expanded by an internal radial force such as a balloon, or a combination of self-expanding and expandable balloon.

[0004] Balloon catheters are used in a number of endovascular applications including blood flow that occludes temporarily or permanently either distal or proximal to a treatment site during neurological examinations, assisting in the neurovascular embolic treatment of an aneurysm or arteriovenous malformation (AVM), and dilates narrowed blood vessels caused by vasospasm. During therapeutic procedures, such as those mentioned above, rapid aspiration deflation of the balloon catheter quickly restores sufficient or normal blood flow to the brain to avoid potential neurological deterioration, such as weakness, loss of sensation, speech problems, etc.

[0005] Current single lumen balloon catheters have inflation / deflation openings, either drilled or laser drilled in the elongated polymeric distal shaft. An improper seal between the distal balloon tip and the guidewire can lead to blood entering the balloon, which can result in poor balloon visibility and clot formation around the inflation / deflation openings. In an emergency with a balloon catheter, a physician can be forced back by pulling the guidewire proximally outward from the balloon to instantly deflate the balloon to return blood flow to the brain. Poor balloon visibility and the inability to quickly deflate the balloon during a procedure could lead to capillary damage and other serious complications.

[0006] Several different balloon catheters are known, each with certain advantages and disadvantages.

[0007] Published patent application WO 2006/135964 A1 discloses a tubular support element for use in a medical device, according to the preamble of claim 1.

[0008] Published patent application US 2007/0083132 A1 discloses a tubular support element for use in a medical device, which comprises a helical external coil which however does not comprise any segment with an annular shape and therefore does not have bars connection of said segments.

[0009] However, there is an ongoing need to provide alternative balloon catheters, in particular alternative balloon catheters that facilitate isotropic bending and rapid deflation, and methods of manufacturing such catheters.

Summary

The invention is a tubular support element for a catheter, such as a neurovascular balloon catheter, according to claim 1, formed by a plurality of stacked segments along a longitudinal axis of the catheter, where each segment has a shape annular, and a plurality of bars connecting the respective segments in the stack, where the bars meet the respective segments with oblique angles, where each rod can be rotated from a longitudinally adjacent rod by a small rotational angle and where the rods collectively form a helix around the longitudinal axis of the catheter. Respective pairs of adjacent segments in the stack are connected by a respective plurality of rods that collectively form a plurality of helices around the longitudinal axis of the catheter. The rods collectively form a pair of helices that rotate in the same direction about the longitudinal axis of the catheter.

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The catheter support member may further include at least one nested segment configured to seat a fully radiopaque or divided annular indicator band, where a respective segment is disposed on opposite sides of, and adjacent to the nested segment, where the segment is elevated relative to the embedded segment.

[0012] In such an embodiment, a bending stiffness of the support member preferably decreases in a distal direction along the support member. In other embodiments, the flexural stiffness varies along the support member. By way of non-limiting example, the respective segment widths and / or rotational angle of the bars may vary from a proximal segment of the support member to a distal segment of the support member. In one embodiment, a balloon catheter comprising the distal support element further comprises a plurality of grooves formed between respective segments and rods, and a balloon mounted on the segments and having an interior zone in fluid communication with at least one groove. . The balloon can be attached at a proximal end to a polymeric sheath extending over the support member, and at a distal end to a flexible distal tip of the catheter, such that the polymeric sheath and balloon fluidly seal the plurality of support element grooves.

[0013] In one embodiment, a tubular support member for a balloon catheter includes a plurality of respective groups of narrow segments, each comprising a plurality of segments stacked along a longitudinal axis of the catheter. A respective wide segment is disposed between adjacent groups of narrow segments, and a plurality of rods connect respective segments of each group of narrow segments, where the rods connect each group of narrow segments having the same respective rotatable position relative to the longitudinal axis of the catheter. .

[0014] In various embodiments, the tubular support member is configured to improve the performance of the balloon catheter in any or all of the following areas: (1) balloon inflation and deflation time; (2) tensile strength; (3) resistance to bending; (4) follow-up; and (5) stability and resistance to bending / buckling during inflation / deflation of the balloon.

Brief description of the drawings

[0015]

FIG. 1 is a plan view of a balloon catheter constructed in accordance with an embodiment of the invention and arranged in a container.

FIG. 2 is a perspective view of a balloon catheter constructed in accordance with an embodiment of the invention, with inserts showing the catheter shaft, the balloon, and various balloon support shafts.

FIG. 3A is a detailed perspective view of a balloon catheter according to embodiments of the invention. FIG. 3B is a detailed perspective view of various balloon support shafts according to various embodiments of the invention.

FIG. 4 is a perspective view of a balloon support shaft constructed in accordance with an embodiment of the invention.

FIG. 5 is a perspective view of a balloon support shaft constructed in accordance with an embodiment of the invention.

FIG. 6 is a perspective view of the balloon support shaft of Figure 5 in a folded configuration.

FIG. 7 is a detailed side view of a balloon support shaft constructed in accordance with an embodiment of the invention.

FIG. 8 is a detailed side view of an annular segment and two bars of a balloon support shaft constructed in accordance with an embodiment of the invention.

FIG. 9 is a perspective view of a balloon support shaft constructed in accordance with an embodiment of the invention.

FIG. 10 is a perspective view of the balloon support shaft of Figure 9 in a folded configuration.

FIG. 11 is a perspective view of a balloon support shaft that does not form an embodiment of the invention.

FIG. 12 is a perspective view of the balloon support shaft of Figure 11 in a folded configuration. Figures 13A-C are detailed perspective views of balloon support shafts according to various embodiments of the invention.

FIG. 14 is a flow chart showing a method of manufacturing a balloon support shaft according to an embodiment of the invention.

Detailed description of the illustrated embodiments

[0016] For the following defined terms these definitions shall apply, unless a different definition is provided in the claims or elsewhere in this specification.

[0017] It is assumed that all numerical values ​​have to be modified here in the en-term regardless of whether it has been indicated or not. The term in generally refers to a range of numbers

ES 2 807 348 T3 that would be considered equivalent to the quoted value (that is, with the same function or result). In many cases, the terms in can include numbers that are rounded to the nearest significant number. The target number range enumeration includes all numbers within that range (for example, 1 through 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). As used in this specification and the appended claims, the singular forms a, an / an, and the / a include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term or is generally used in its sense with and / or unless the content clearly dictates otherwise.

[0018] FIG. 1 is a plan view of a balloon catheter 10 disposed in a blood vessel 12. The balloon catheter 10 includes a balloon 14 configured to expand and seal vessels 12 in the anatomy of a patient. The balloon catheter10 can be used for intravascular procedures. For example, balloon catheter 10 can be used in conjunction with other medical devices, such as a stent or vaso-occlusive device, to treat and / or diagnose a medical condition.

[0019] FIG. 2 shows a balloon catheter 10 with a long member 16 having a proximal portion 18 and a distal portion 20. In FIG. 2, much of the proximal portion 18 is looped to show the entire design of the catheter shaft. An inflation source 22, such as a 1cc or 3cc syringe 22, is attached to the long member 16 at its proximal end using a three-way stopcock. A balloon 14 is attached to the distal end of the long member 16. The balloon 14 is also shown in an insert (2a) in sufficient detail to show the balloon support axis 24 at the distal portion 20 of the long member 16. A second insert (2b) shows several balloon support axes 24 according to various embodiments of the invention. A third insert (2c) shows a reinforced catheter shaft in proximal portion 18 of long member 16.

[0020] Figures 3A-8 show various features of the balloon support shaft 24 according to an embodiment of the invention that will be discussed in greater detail below. As shown in Figures 3B, 4, 5, and 7, the balloon support shaft 24 has a tubular member 26 with grooves 28 formed therein. When a balloon 14 is supported on a balloon catheter10, as shown in FIG. 3A, at least a part of the tubular element 26 is disposed within the balloon 14. Tubular member 26 defines a lumen 30 that houses a guidewire (not shown) and provides a fluid path for inflation and deflation of balloon 14. The structure of tubular member 26 allows fluid communication between lumen 30 and balloon 14 to through slots 28. A guidewire seal is provided at the distal end of balloon 14 to provide a fluid seal around the guidewire. Inflation source 22 is fluidly connected to lumen 30 into which inflation fluid and contrast medium can be introduced and withdrawn. The introduced fluid travels from the proximal opening of lumen 30 around guidewire provided in lumen 30, through slots 28, and into balloon 14 to facilitate inflation and deflation of the balloon.

[0021] FIG. 7 shows the detailed structure of a tubular element 26 according to the invention.

Tubular member 26 is generally a stack of annular segments 32. Tubular member 26 includes a plurality of grooves 28 formed therein. Various embodiments of groove 28 arrangements and configurations are contemplated. In some embodiments, at least some, if not all of the grooves 28 are disposed at the same or a similar angle relative to the longitudinal axis of tubular member 26. As shown, the grooves 28 may be arranged at an angle that is perpendicular or substantially perpendicular, and / or may be characterized as being arranged in a plane perpendicular to the longitudinal axis of tubular member 26. However, in other embodiments they are Grooves 28 may be disposed at an angle that is not perpendicular, and / or may be characterized as being disposed in a plane not perpendicular to the longitudinal axis of tubular member 26.

Additionally, a group of one or more grooves 28 may be arranged at different angles relative to another group of one or more grooves 28. The distribution and / or configuration of grooves 30 may also include, for the applicable extent, any of those described. in US Patent No. 7,878,984.

The grooves 28 enhance the flexibility of the tubular member 26 while retaining adequate torque transmission characteristics. The grooves 28 are formed so that the annular segments 32 are interconnected by one or more bars 34, that is, the portion of the tubular element 26 that remains after the grooves 28 are formed therein. This interconnected structure exhibits a relatively high degree of torsional stiffness, while maintaining a desired level of lateral flexibility. In some embodiments some adjacent grooves 28 may be formed, including portions that overlap each other around the circumference of tubular member 26. In other embodiments some adjacent grooves 28 may be arranged so that they do not necessarily overlap each other, but are arranged in a pattern that provides the desired degree of lateral flexibility.

Furthermore, to achieve desired properties the grooves 28 may be arranged along the length or around the circumference of the tubular member 26.

For example, adjacent grooves 28 or groups of grooves 28 may be arranged, in a symmetrical pattern, such as arranged essentially in the same way on opposite sides around the circumference of tubular member 26, or they may be rotated at an angle to each other about of the axis of the tubular element 26. In addition, adjacent grooves 28 or groups of grooves 28 equally spaced may be provided along the length of the tubular element

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26, or they can be arranged in an increasing or decreasing density pattern, or they can be arranged in a non-symmetrical or irregular pattern. Other characteristics, such as slot size, slot shape, and / or slot angle relative to the longitudinal axis of tubular member 26, can also be modified along the length of tubular member 26 to vary flexibility or other properties. In other embodiments, furthermore, it is contemplated that the tubular member parts may not include any of these grooves 28.

As suggested above, the grooves 28 can be formed in groups of two, three, four, five, or more grooves 28, which can be located at substantially the same location along the axis of the tubular element 26. Alternatively , a single slot 28 may be provided at some or all of these locations. Groove groups 28 may include grooves 28 that are equal in size (ie span the same circumferential distance around tubular member 26). In some of these as well as other embodiments, at least some grooves 28 in a group are unequal in size (ie, span a different circumferential distance around tubular member 26). Longitudinally adjacent groups of grooves 28 may have the same or different configurations.

[0025] For example, some embodiments of tubular member 26 include grooves 28 that are equal in size in a first group and then unevenly sized in an adjacent group. It can be seen that in groups having two grooves 28 that are equal in size and that are symmetrically arranged around the tubular circumference, the centroid of the pair of bars 34 coincides with the central axis of tubular member 26. In contrast, in groups having two grooves 28 that are unequal in size and whose bars 34 are directly opposite on the tubular circumference, the centroid of the pair of bars 34 is offset from the central axis of the tubular member 26. Some embodiments of the tubular element 26 include only groups of grooves with centroids that coincide with the central axis of the tubular element 26, only groups of grooves with centroids that are offset from the central axis of the tubular element 26, or groups of grooves with centroids which coincide with the central axis of tubular member 26 in a first group and are offset from the central axis of tubular member 26 in another group. The amount of deflection can vary depending on the depth (or length) of grooves 28 and can include essentially any suitable distance.

[0026] The grooves 28 can be formed by methods such as micromachining, saw cutting (for example, using a diamond drawn by semiconductor cutting blade), electron discharge machining, forging, milling, casting, molding, treatment or chemical etching. or other known methods, and the like. In some such embodiments, the structure of the tubular member 26 is formed by cutting and / or removing portions of the tube to form grooves 28. Examples of suitable micromachining methods and other cutting methods and structures for slotted tubular elements and medical devices including tubular elements are described in US patents 2003/0069522 and 2004/0181174-A2; and in US patents 6,766,720 and 6,579,246. Examples of etching processes are described in US Patent 5,106,455.

[0027] It should be understood that methods for manufacturing balloon catheter 10 may include forming grooves 28 in tubular member 26 using any of these or other manufacturing steps. For example, grooves 28 can be formed in the tubular member using a laser cutting process. The laser cutting process can include essentially any suitable laser and / or laser cutting apparatus. For example, the laser cutting process can use a fiber laser. The use of laser cutting processes is desirable for several reasons.

For example, laser cutting processes can allow tubular member 26 to be cut into several different cutting patterns in a precisely controlled manner. This can include variations in slot width (which may also be referred to as "cut"), annular segment width, bar height and / or width, and so on. Additionally, changes to the cutting pattern can be made without the need to replace the cutting instrument (for example, a blade). This can also allow smaller tubes (eg, with a smaller outer diameter) to be used to form tubular member 26 without being limited by a minimum cutting blade size. As a consequence, tubular elements 20 can be manufactured for use in neurological devices or other devices for which a small size may be desired.

Due to the precision and control that can be achieved by cutting grooves 28 with a laser, much additional variation in arrangements, configurations, etc. can be achieved. of slot 28. Still referring to FIG. 7, a side view of tubular member 26 is illustrated. Tubular member 26 includes a plurality of annular segments 32 including annular segment 32a, annular segment 32b, and annular segment 32c. In this example, segment 32a is arranged longitudinally adjacent (ie, just next to) segment 32b and segment 32c is arranged longitudinally adjacent to adjacent segment 32b (oppositely segment 32a). The number of annular segments 32 in a given tubular member 26 may vary depending on the structure of tubular member 26. For example, as the number of grooves 28 increases, the number of annular segments 32 may similarly increase. The invention is not intended to be limited to a particular number or arrangement of annular segments 32 for any given tubular element 26 or device with a tubular element 26.

[0029] It can be understood that segments 32a / 32b / 32c are generally circumferential or round portions of tubular element 26 that are defined between groups or sets of grooves 28. For example, segment 32a is defined between a first group of grooves 28a and a second group of grooves 28b. Likewise, segment 32b

ES 2 807 348 T3 is defined between group 28b and a third group of slots 28c. Furthermore, segment 32c is defined between group 28c and a fourth group of slots 28d. In this example, each group 28a / 28b / 28c / 28d includes two slots 28. However, any suitable number of slots 28 can be used for any group 28a / 28b / 28c / 28d. Like annular segments 32, the invention is not intended to be limited to any number of grooves 28, groups of grooves 28, or number of grooves 28 per group for any given tubular element or device 26 that includes a tubular element 26 with grooves 28.

[0030] When grooves 28 are formed in tubular member 26, a portion of tubular member 26 remains at the longitudinal location where grooves 28 are formed and extends between longitudinally adjacent annular segments 32. This portion is called a bar 34.

Several bars 34 are illustrated in FIG. 7 including bar 34a, bar 34a ', bar 34b, bar 34b', bar 34c, bar 34c ', bar 34d, and bar 34d'. The bars 34a / 34a '/ 34b / 34b' / 34c / 34c '/ 34d / 34d' can be understood to be parts of the tubular element 26 connecting or aggregating longitudinally adjacent annular segments 32. Each pair of longitudinally adjacent annular segments (eg, 32a and 32b) is joined by two bars (eg, 34b and 34b '), which form a bar pair at the same longitudinal location along the tubular member 26. From Similarly, segment 32b is joined to segment 32c by bars 34c and 34c '. In this example, each group 28a / 28b / 28c / 28d of grooves 28 defines or leaves behind two corresponding bars with a given longitudinal location. In FIG. 7, illustrating the tubular element 26 from the side, one bar (e.g. 34a, 34b, 34c, 34d) of each pair of bars can be viewed from the front and the other bar (e.g. 34a ', 34b', 34c ', 34d') of the bar pair can be seen from behind and is shaded for clarity.

Bars 34, 34 'are formed in tubular member 26 so that they meet annular segments 32 at an oblique angle, as shown in FIG. 8. Furthermore, each pair of bars is formed in the tubular member 26 so as to rotate about the longitudinal axis of the tubular member 26 of the preceding pair of bars. In this embodiment, each pair of bars is angularly displaced or rotated approximately eight degrees from the preceding pair of bars, resulting in a complete rotation about for every 45 pairs of bars. The pairs of bars form a double helix structure along the length of the tubular member 26 by the oblique angle between the bars 34 and the annular segments 32, and the angular displacement between the pairs of bars. These propellers, which rotate in the same direction, are shown in figures 2, 3, 5, and 6.

As the angle of rotation between adjacent bars 34 is reduced, the portion of the annular segment 32 between the bars 34 shortens until it is non-existent on one side and is completely isolated from loads (bending, tension and compression) on the other. side. In embodiments having small angles of rotation, such as that depicted in FIG. 5, the bars 34 form a continuous helix. When such a structure is placed in compression or tension the helical line of the pairs of bars acts as a continuous pair of fibers that effectively prevent a change in length of the structure. When loaded in tension, the fibers are prevented from bending inward and smoothed out by the spring support of the annular segments 32. On the contrary, when loaded in compression, individual buckling of the fibers outward is prevented. by ring segments 32.

[0033] As shown in FIG. 6, the double helix arrangement of the bars 34 causes the tubular element 26 to fold in a segmented manner, with further bending in the first zone 36 where the pair of bars in the helix defines an axis approximately parallel to the plane of bending. . There is almost no flex in the second zone 38, where the bar pair axis is perpendicular to the flex plane. Increasing the slope of the coils increases the likelihood of multiple fold zones 36 in the tightest predicted radius of curvature of balloon catheter 10. As the angle of rotation between adjacent pairs of rods increases, the angle of the helix becomes narrower and the tubular member 26 can begin to rotate in a ring when bent. Helix angle can be optimized to maximize both axial stiffness and isotropic properties in flexure.

Increasing the number of bars 34 connecting each pair of annular segments 32 results in a tubular element 26 with more isotropic flexure. Increasing the number of connecting bars 34 from two to three gives the structure a more frequently repeated symmetry along its length. For example, a two-bar structure (FIGS. 2, 3, 5, and 6) is symmetric every 180 degrees of rotation while a three-bar structure (FIGS. 9 and 10) is symmetric every 120 degrees of rotation. The three-bar structure will not be as smooth as a two-bar structure, and may be more useful in proximal areas of the balloon catheter where superior stiffness is desired.

[0035] Forming groups 46 of bars 34 and narrow annular segments 32 that are rotated a small amount, such as 90 degrees, from each other, where the groups 46 are joined by wider annular segments 44 also results in a more tubular structure. isotropic 26. The wider annular segments 44 are wide enough to resist extension. Figures 11 and 12 show an example of such a structure. The bars 34 in each group 46 are all aligned in this example, however they could also have a spiral pattern.

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Like slot groups 28a / 28b / 28c, the invention is not intended to be limited to any number of bars 34, groups of bars 34, or number of bars 34 per group for any given tubular element 26 or device including a tubular element 26 with bars 34.

[0037] In a typical transvascular device, such as a balloon catheter10, the proximal area of ​​the device is normally in less tortuous anatomy and the flexural stiffness is greater to allow the device to be pushed without bending or buckling. Accordingly, it is desirable to create a microfabricated structure with rigidity that varies along the length of the device. For example, the stiffness can decrease and / or increase along the length of the device. The stiffness can also decrease, then increase and / or increase and then decrease. The stiffness of the structure can be adjusted by increasing the bar 34 and / or dimensions of the annular segment 32. These are usually varied at the same time to create a structure with a more uniform distribution of stress. However, as the width of the dimension of the annular segment 32 increases, the slope of the helix decreases, so that there are fewer areas of flex per length, as shown in Figures 13A and 13B. To compensate for this effect, the rotary angle between sets of bars 34 (two, three, or more bars) can be varied proportionally to the width of annular segment 32 to maintain a relatively constant helical slope along the length of the tube. device. Compare Figures 13A and 13B. It can be seen from Figures 13A to 13C that as the width of the annular segment 32 increases, the rotational angle can be increased without creating creating ring structures that will be loaded in flexion, tension or compression. This results in a device with increased flexural stiffness and improved buckling and buckling capacity, while still maintaining relatively isotropic bending retention properties. In other embodiments the annular segment widths and rotational angles may vary (ie, increase or decrease).

[0038] When tubular member 26 is used as the central support shaft in a single lumen balloon catheter 10, as shown in Figures 1-3, the plurality of slots 28 allow for rapid inflation and deflation of the balloon. The grooves 28 are separated and dimensioned to create an extremely porous structure that allows inflation and deflation of the lumen 30 of the tubular element 26 in the balloon 14. The ease of inflation and deflation allow the use of a higher contrast medium, which improves visibility of the balloon under fluoroscopy. The configuration of the grooves also provides good axial strength (in tension and compression) as well as resistance to kinking and ovalization as it enters the tortuous vasculature. Furthermore, the tracking of the balloon catheter10 is improved by varying the flexural stiffness of the tubular element 26, so that it is softer at its distal end. In addition, the tubular member 26 is more resistant to bending and buckling during inflation and deflation of the balloon.

[0039] During the inflation of conformal balloons it is possible that compressive forces are created along the central axis of the balloon. Traditional single lumen balloon catheters use a plastic shaft with drilled holes for fluid passage. The shaft must be stiff enough to resist buckling but smooth enough to advance easily through the tortuous vasculature. A simple plastic tube is not easily modified to vary stiffness along its length and is also susceptible to local bending. The structure is highly resistant to kinking and easily varies in stiffness by changing the height of the bars, the widths of the cut, the spacing of the cuts, the wall thickness, etc. Column buckling (Euler buckling), regardless of end limitations, is linearly proportional to bending stiffness and varies inversely with the length of the column squared. In this way, by strengthening the proximal part of a shaft and smoothing the distal end, it is possible to create a net gain in buckling resistance while maintaining a smooth distal end, particularly for longer and larger balloon sizes (critical for atraumatic tracking). Alternatively, softening the stiffness profile of the entire shaft for shorter and smaller balloons to create maximum distal flexibility can provide better conduction.

The tubular element 26 and / or other components of the balloon catheter 10 can be manufactured from a metal, metal alloy, polymer (some examples are described below), a composite metallic polymer, ceramics, combinations thereof, and the like, or any other suitable material. Some examples of suitable metals and metal alloys include stainless steel, such as 304V, 304L, and 316LV stainless steel; ductile steel; nickel-titanium alloy such as linear elastic and / or super elastic nitinol; other nickel alloys, such as nickel-chromium-moly alloys (for example, UNS: N06625 such as INCONEL® 625, UNS: N06022 such as HASTELLOY® C-22®, UNS: N10276 such as HASTELLOY® C276®, other HASTELLOY® alloys, and the like), nickel-copper alloys (for example, UNS: N04400 such as MONEL® 400, NICKELVAC® 40o, NICORROS® 400, and the like), nickel-cobalt chromium-moly alloys (for example, UNS: R30035 such as MP35-N® and the like), nickel-moly alloys (for example, UNS: N10665 such as HASTELLOY® ALLOY B2®), other nickel-chromium alloys, other nickel-moly alloys, other nickel alloys - cobalt, other nickel-iron alloys, other nickel-copper alloys, other nickel-tungsten or tungsten alloys, and the like; cobalt-chromium alloys; cobalt chromomolybdenum alloys (eg, UNS: R30003 such as FLGILOY®, PHYNOX®, and the like); platinum-enriched stainless steel; titanium; combinations thereof; and the like; or any other suitable material.

[0041] As mentioned above, within the family of commercially available nickel-titanium or nitinol alloys, there is a category designated linear elastic or non-super elastic which, although it may be similar in chemistry to conventional shape memory and varieties super elastic, can show

ES 2 807 348 T3 different and useful mechanical properties. Linear elastic nitinol and / or non-super elastic nitinol can be distinguished from super elastic nitinol in that linear elastic and / or non-super elastic nitinol does not show a substantial super elastic plateau or indicator zone in its stress / extension curve as does the super elastic nitinol. In contrast, in linear elastic and / or non-superelastic nitinol, as recoverable extension increases, stress continues to increase substantially linearly, or to some extent, but not necessarily in fully linear relationship until plastic deformation begins or at less in a relationship that is more linear than the super elastic plateau and / or indicator zone that can be seen with super elastic nitinol. Thus, for the purposes of this disclosure linear elastic and / or non-super elastic nitinol may also be referred to as substantially linear elastic and / or non-super elastic nitinol.

[0042] In some cases, linear elastic and / or non-super elastic nitinol can also be distinguished from super elastic nitinol in that linear elastic and / or non-super elastic nitinol can accept up to about 2-5% extension while remaining substantially elastic (eg, before plastically deforming) whereas super elastic nitinol can accept an extension of up to about 8% before plastically deforming. Both materials can be distinguished from other linear elastic materials such as stainless steel (which can also be distinguished based on its composition), which can accept only about 0.2-0.44% extension before plastically deforming.

[0043] In some embodiments, the linear elastic and / or non-super elastic nickel-titanium alloy is an alloy that does not show changes in any martensite / austenite phase that are detectable by DSC and DMTA analysis over a wide range of temperature. For example, in some embodiments, there may be no detectable martensite / austenite phase by DSC and DMTA analysis in the range of about 60 ° C. up to about 120 ° C. in the linear elastic and / or non-super elastic nickel-titanium alloy. The mechanical flexural properties of such a material can therefore remain generally inert to the effect of temperature over this very wide temperature range. In some embodiments, the mechanical flexural properties of the linear elastic and / or non-super elastic nickel-titanium alloy at room or indoor temperature are substantially the same as the mechanical properties at body temperature, for example, in that they do not show a plateau zone and / or super elastic indicator zone. In other words, the linear elastic and / or non-super elastic nickel titanium alloy maintains its linear elastic characteristics and / or non-super elastic properties over a wide temperature range.

[0044] In some embodiments, the linear elastic and / or non-super elastic nickel-titanium alloy may be in the range of about 50 to about 60 weight percent nickel, the balance being essentially titanium. In some embodiments, the composition is in the range of about 54 to about 57 weight percent nickel. An example of a suitable nickel-titanium alloy is FHP-NT, an alloy commercially available from Furukawa Techno Material Co. of Kanagawa, Japan. Some examples of nickel-titanium alloys are described in US Patent Nos. 5,238,004 and 6,508,803. Other suitable materials may include ULTANIUM ™ (available from Neo-Metrics) and GUM METAL ™ (available from Toyota). In some other embodiments, a super elastic alloy, for example a super elastic nitinol, can be used to achieve desired properties.

[0045] In at least some embodiments, part or all of the tubular member 26 may also be coated with, manufactured from, or otherwise included a radiopaque material. By radiopaque materials are meant materials capable of producing a relatively bright image on a fluoroscopic screen or other imaging technique during a medical procedure. This relatively bright image assists the balloon catheter10 user in determining its location. Some examples of radiopaque materials may include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloy, polymeric material filled with a radiopaque filler, and the like. In addition, other radiopaque marker bands and / or coils can also be incorporated into the balloon catheter 10 design to achieve the same result.

[0046] In some embodiments, a degree of MRI compatibility is imparted on the balloon catheter10. For example, to improve compatibility with magnetic resonance imaging (MRI) machines, it may be desirable to fabricate tubular member 26, or other parts of balloon catheter 10, in a way that imparts a degree of MRI compatibility. For example, the tubular element 26, or parts thereof, can be made of a material that does not substantially distort the image and create substantial artifacts (artifacts are gaps in the image). Certain ferromagnetic materials, for example, may not be suitable because they can create artifacts in an MRI image. Tubular element 26 or parts thereof can also be made of a material with which the MRI machine can reproduce an image. Some materials exhibiting these characteristics include, for example, tungsten, cobalt-chromium-moly alloys (for example, UNS: R30003 such as ELGILOY®, PHYNox®, and the like), nickel-cobalt-chromium-moly alloys (for example, UNS: R30035 such as MP35-N® and the like), nitinol, and the like and others.

[0047] The entire balloon catheter 10 can be made of the same material along its length, or in some embodiments, it can include parts or sections made of different materials. In some embodiments, the material used to construct a balloon catheter 10 is chosen to impart characteristics of varying rigidity and flexibility to different parts of a balloon catheter 10. For example, the proximal section 18 and the distal section 20 of the

ES 2 807 348 T3 balloon catheter 10 can be formed of different materials, for example, materials that have different moduli of elasticity, resulting in a difference in flexibility. In some embodiments, the material used to construct proximal section 18 can be relatively rigid to push and torsion, and the material used to construct distal section 20 can be relatively flexible by comparison for better orientability and lateral traceability. For example, proximal section 18 can be formed from a polyimide shaft and / or lined with polytetrafluoroethylene (PTFE) with variable peak braid of 304v stainless steel wire or tape, or cross wound with variable spacing and distal section 20 can be form with outer layer of multidurometer polymer such as PEBAX® over the reinforced variable peak / gap structure.

[0048] In embodiments where different parts of balloon catheter 10 have been made of different materials, the different parts can be connected using any suitable connection technique and / or with a connector. For example, the different portions of the balloon catheter 10 can be connected using welding (including welding / laser bonding), soldering, brazing, adhesive, heat bonding, or the like, or combinations thereof. These techniques can be used regardless of whether a connector is used or not. The connector can include any generally suitable structure for connecting portions of a balloon catheter. An example of a suitable structure includes a structure such as a hypotube or a coiled wire having an internal diameter appropriately sized to receive and connect the ends of the proximal portion and the distal portion. Essentially any suitable configuration and / or structure can be used to connect various parts of balloon catheter 10, including those connectors described in US Patent Nos. 6,918,882 and 7,071,197 and / or in US Patent No. 2006-0122537.

[0049] As shown in FIG. 7, a polymeric sheath 40 is laminated onto the tubular element 26. The polymeric sheath 40 may be disposed over parts or all of the tubular element 26 that can define a generally smooth outer surface for the balloon catheter 10. However, in other embodiments , such sheath 40 or cover may be absent from part or all of balloon catheter 10, so that tubular member 26 may form the outer surface. The casing 40 can be made from a polymer or any other suitable material. Some examples of suitable polymers may include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene (POM, for example , DELRIN® available from DuPont), polyether block ester, polyurethane (e.g. 85A polyurethane), polypropylene (PP), polyvinyl chloride (PVC), polyether ester (e.g. ARNITEL® available from DSM Engineering Plastics), ether or ester based copolymers (for example, butylene / poly (alkylene ether) phthalate and / or other polyester elastomers such as hYtREL® available from DuPont), polyamide (for example, DURETHAN® available from Bayer or CRISTAMID® available from Elf Atochem), elastomeric polyamides, polyamide / block ethers, polyether block amide (PEBA, for example available under the trade name PEBAX®), Ethylene Vinyl Acetate (EVA) Copolymers, Silicones, Polyethylene (PE), Marlex High Density Polyethylene, Marlex Low Density Polyethylene, Linear Low Density Polyethylene (e.g. REXELL®), Polyester, Polybutylene Terephthalate (PBT) , polyethylene terephthalate (PET), polytrimethylene terephthalate, polyethylene naphthalate (PEN), polyetheretherketone (PEEK), polyimide (PI), polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polyparaphenylene terephthalamide (e.g. KEVLAR®), polysulfone, nylon, nylon-12 (such as GRILAMID® available from EMS American Grilon), perfluoro (propyl vinyl ether) (PFA), ethylene vinyl alcohol, polyolefin, polystyrene , epoxy, polyvinylidene chloride (PVdC), poly (styrene-b-isobutylene-b-styrene) (e.g. SIBS and / or SIBS 50A), polycarbonates, ionomers, biocompatible polymers, other suitable materials, or mixtures, combinations, copolymers thereof, polymer / metal composites, and the like. In some embodiments, the shell 40 can be mixed with a liquid crystal polymer (LCP). For example, the mixture can contain up to about 6% LCP.

[0050] In some embodiments, the outer surface of balloon catheter 10 (including, for example, the outer surface of tubular member 26), can be sandblasted, spherical, sodium bicarbonate treated, electropolish, etc. In these embodiments, as in some others, a coating, for example a lubricated, hydrophilic, protective, or other coating, can be applied over parts or all of the wrapper 40, or in examples without a wrapping over the part of the tubular element, or other parts of the device 10. Alternatively, the liner 40 may comprise a lubricated, hydrophilic, protective or other coating. Hydrophobic coatings such as fluoropolymers provide dry lubricity that improves device handling and device exchanges. Lubricated coatings improve maneuverability and enhance injury crossover ability. Suitable lubricated polymers are well known in the art and may include silicone and the like, hydrophilic polymers such as polyarylene oxides, polyvinylpyrrolidones, polyvinyl alcohols, hydroxy alkyl cellulosics, alginines, saccharides, caprolactones, and the like, and mixtures and combinations thereof. . Hydrophilic polymers can be mixed with each other or with formulated amounts of water-insoluble compounds (including some polymers) to produce coatings with adequate lubricity, bonding, and solubility. Some other examples of such coatings and materials and methods used to create such coatings can be found in US Patent Nos. 6,139,510 and 5,772,609.

The shell 40 can be formed, for example, by coating, extrusion, coextrusion, interrupted layer coextrusion (ILC), or casting of various end-to-end segments. The layer may have a stiffness

ES 2 807 348 T3 uniform or a gradual reduction in stiffness from the proximal end to the distal end thereof. The gradual reduction in stiffness may be continuous as per ILC or it may be stepped as by melting separately extruded tubular segments together. The wrapper 40 can be impregnated with radiopaque fillers, such as barium sulfate, bismuth, or tungsten to facilitate radiographic visualization.

[0052] The distal portion of the balloon 14 is attached to the distal end of the tubular member 26 and to the distal flexible distal tip of the inflation ports / irrigation channels. Balloon 14 is positioned in tubular member 26 such that balloon 14 covers a portion of tubular member 26 that has grooves 28 formed therein. Balloon 14 can be made of a highly compatible material that expands elastically upon pressurization. Because the balloon 14 elastically expands from the deflated state to the inflated state, the balloon 14 has an extremely low profile in the deflated state and can be used without bending the balloon. The balloon may be formed of silicone, urethane polymer, or extruded thermoplastic elastomer polyisoprene rubber such as 70a, 65A, 60A, 52A, 45A, 42A, 40A, 32A, 30A, 25A hydrogenated polyisoprene rubber, 15A, 12A, and 5A, which is commercially available under the trade names Chronoprene ™ and Mediprene ™ from AdvanSource Biomaterials, Inc. and Elasto, respectively. Hydrogenated polyisoprene provides a balloon that has superior performance and manufacturing attributes. In particular, the hydrogenated polyisoprene can be processed with standard polyolefin processing equipment to obtain balloon tubing with a wall thickness of about 0.001 inches to 0.010 inches and a corresponding internal diameter of about 0.016 inches to 0.058 inches. Such tubing produces balloons having a nominal inflated outer diameter of approximately 3.0mm to 7.5mm. The highly compliant balloon preferably expands elastically at pressures of less than 1.0 ATM. The highly compliant balloon can have a pressure compatibility of 2.0 mM / ATM or more at pressures of less than 2.0 ATM. The highly compatible balloon can have a volumetric compatibility of approximately 0.3 mm by 0.01 ml to 0.5 mm by 0.01 ml at pressures of less than 2.0 ATM, for balloons with a nominal diameter of approximately 3, 5mm and a length of approximately 10mm to 30mm. The ends of the balloon are attached to the tubular member 26 and the flexible distal tip using conventional attachment means such as thermal bonding using a hot jaw, hot air source, or a laser. The tubular member 26, excluding the balloon 14 and the distal flexible tip, can be coated with hydrophilic coatings such as Hydropass, Hydrolene or Bioslide.

[0053] As shown in FIG. 4, marker bands 42 are mounted on tubular member 26. FIG. 5 shows wide hollow annular segment 32 configured to support cylindrical marker band 42 in FIG. 4. In addition, the annular segments 32 on each side of the wide hollow annular segment 32 are raised relative to the wide hollow annular segments 32 (not beyond the outer diameter of the tubular member 26) to retain the marker band 42 therein. Marker band 42 can be made from a full band, a slit band, or a coil of round wire or ribbon made of materials such as platinum / tungsten, gold. Marker band 42 can also be made of a low durometer polymer or any other suitable material impregnated with radiopaque fillers such as barium, bismuth or tungsten sulfate to facilitate radiographic visualization. Some examples of suitable polymers may include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), elastomeric polyamides, polyamide / block ethers, polyether block amide (PEBA, for example, available under the trade name of PEBAX®).

[0054] As shown in FIG. 14, a balloon catheter 10 can be manufactured by first mounting a tubular member 26 in a cutting device (passage 50). Next, a first annular segment 32 of the tubular member 26 is passed distally through the trimming device (passage 52). Then, a first slot 28 is formed in tubular member 26 proximal to first annular segment 32, for example, by laser cutting (step 54). Subsequently, a first oblique angle is formed at a first end of the first slot 28 (step 56).

[0055] Next, a second oblique angle perpendicular to the first oblique angle is formed at a second end of the first slot 28 (step 58). Then, the tubular member 26 is rotated 180 degrees about its longitudinal axis (step 60). Subsequently, a second slot 28 is formed in tubular member 26 proximal to first annular segment 32 (passage 62).

[0056] Next, a third oblique angle is formed at a first end of the second slot 28 (step 64). Then, a fourth oblique angle, perpendicular to the first oblique angle, is formed at a second end of the second slot 28 (step 66). Subsequently, the next annular segment 32 of the tubular member 26 is passed distally through the cutting device (step 68).

[0057] The tubular element is then rotated a small angle (approximately eight degrees) about its longitudinal axis (pitch 70). Steps 54 to 70 are repeated until a plurality of grooves 28 have been cut in tubular member 26 (step 72), at which point tubular member 26 is removed from the trimming device (step 74). In some embodiments the tubular element is covered with a polymer coating 40.

[0058] Finally, when making a balloon catheter 10, a balloon 14 is attached to the tubular member 26 so that the balloon 14 defines a lumen in communication with at least one slot 28.