High pressure balloon and its manufacturing method

Abstract

Disclosed herein is a flexible high pressure angioplasty balloon that utilizes an inflatable balloon disposed on a catheter and a support structure secured on or along the catheter at a first location proximal to the balloon and a second location distal to the balloon. Inflating the balloon reconfigures the support structure to encourage the first and second locations to approach each other, thereby inhibiting longitudinal stretch of the balloon relative to the catheter. The support structure may surround, support, or otherwise extend the entire length of the balloon, and maintain high flexibility of the balloon, allowing it to bend and curve even at relatively high inflation pressures.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE This application relates to balloon catheters and methods of making and using same. More particularly, this application relates to angioplasty catheters that include a balloon that maintains flexibility and / or shape upon inflation, and methods of making and using such catheters.

[0002] Related Application Data This application claims the benefit of co-pending U.S. Provisional Application No. 63 / 319,309, filed March 12, 2022, the entire disclosure of which is expressly incorporated herein by reference. [Background technology]

[0003] Conventional angioplasty balloons are generally constructed of low-compliance materials that can withstand high inflation pressures and achieve a uniform, predictable diameter in vivo, even when the surrounding artery is partially narrowed and calcified. A typical balloon has a cylindrical section of uniform diameter between conical ends and a central catheter that extends along the longitudinal axis of the balloon. When inflated at high pressure, the walls of the balloon are placed under tension, biasing the balloon into a rigid, straight configuration. Such balloons impose this straight cylindrical configuration on a balloon-expandable stent that is crimped or otherwise held on the balloon for expansion.

[0004] The presence of a straight stent in a curved artery (e.g., coronary, renal, femoral, etc.) places stresses or strains on the stent structure, the artery, or both, especially when the artery is in motion. The resulting repeated microtrauma induces inflammation, hyperplasia, and recurrent stenosis, often until blood flow becomes severely restricted.

[0005] Previous attempts to provide flexibility to angioplasty balloons have employed segmentation, helical geometries, and compliant balloon materials. Segmented balloons come in a variety of forms depending on the degree of segmentation. For example, previous devices have included a spherical balloon stretched along a central catheter with thin intervening segments that easily bend. However, such balloons are not suitable for stent delivery because they impose an irregular, segmented shape on the stent. If a segmented balloon is inflated to the extent that it removes the gaps between the segments to deliver a more fully expanded stent, adjacent segments will interfere with each other and flexibility will be greatly reduced.

[0006] Other proposed balloons include adjacent segments separated by grooves in a continuous balloon. These local "hinge points" do little to improve differential stretchability and therefore have a modest effect on balloon flexibility. Other balloons have deep grooves that separate bulges in the balloon profile, but they also have a limited effect on flexibility.

[0007] Spiral balloons have also been used to increase flexibility, but the turns of the balloon break the longitudinal continuity so that adjacent turns on the outside of a balloon bend can move apart, while adjacent turns on the inside remain close together. The resulting differential stretching potential provides some flexibility. Spiral balloons also benefit from a multi-lumen structure. Each of the component balloons is thinner and therefore more flexible than the resulting spiral. However, such spiral balloons suffer from many of the same limitations as segmented balloons. They may deliver stents that are not fully expanded or are less flexible if overinflated to eliminate gaps. Furthermore, even when the balloon is straight, its components have sharp bends that will straighten out with high pressure inflation unless tightly restrained, quickly causing the spiral balloon to break apart. Non-compliant tightly wound spiral balloons can potentially break apart during high pressure inflation. A more loosely wound spiral balloon is more stable but less flexible.

[0008] Balloons constructed from compliant materials are more flexible than similar balloons constructed from non-compliant materials. However, compliant balloons tend to expand in the direction of least resistance and therefore may not generate enough force to initiate stent expansion, thereby leaving narrow areas untreated, rupturing arteries in weak areas, and / or extending beyond the intended area of ​​angioplasty. Early angioplasty balloons made from compliant materials were subsequently reinforced by the application of various braids, meshes, and wraps to control the shape and dimensions of the balloon at higher operating pressures.

[0009] Also, all kinds of external braids, wraps and weaves have been embedded into the low-compliance walls to further increase the maximum operating pressure. However, incorporating braids into the low-compliance walls of high-pressure balloons prevents the braids from changing angle. The braids in such balloons do not freely open and close or stretch as the balloon inflates and deflates. As a result, the presence of the braids does nothing to shorten the balloon, relieve longitudinal tension, create extra pleats in the wall, increase flexibility, or prevent a forced straight conformation during inflation.

[0010] Additionally, high pressure inflation of a non-compliant angioplasty balloon exerts an outward force on the inner surface of the balloon. Pressure acting on the mid-section of the balloon generates a transaxial force, while pressure acting on the ends of the balloon generates an axial force. Generally, the transaxial force produces the desired dilating effect on the surrounding artery. Meanwhile, the axial force has less effect on the mid-section of the balloon and more on the ends of the balloon, causing both ends of the balloon to stretch and straighten out into a roughly cylindrical shape, regardless of the shape of the surrounding artery.

[0011] Thus, there is a need for a balloon that remains flexible and / or retains a curved shape when inflated at high pressures. Summary of the Invention

[0012] The present application is directed to balloon catheters, and more particularly to angioplasty balloon catheters that include a non-compliant balloon that maintains flexibility and / or shape upon inflation, and methods of making and using such balloon catheters.

[0013] The patent literature is replete with balloon designs that purportedly avoid forced straightening while maintaining the non-cylindrical shape of the artery, but very few achieve clinically relevant flexibility or conformability. The only exception is the balloon and catheter disclosed in U.S. Patent No. 9,149,612, by the same inventor as the present application, the entire disclosure of which is expressly incorporated herein by reference. The balloon disclosed in this patent carries an outer braid that shortens upon inflation, thereby resisting elongation that would cause the balloon to straighten and become rigid.

[0014] To overcome forced balloon straightening, each end of the balloon and the corresponding end of the braid must be attached to an adjacent segment of the central catheter. Gaps between the ends of the outer braid and the corresponding ends of the balloon can result in compressive loads on the intermediate catheter, resulting in kinking and occlusion of both the catheter's inflation lumen and the guidewire lumen. The larger the balloon and the longer the gap between the balloon / catheter and the braid / catheter attachment site, the more severe the degree of angulation and the associated (potentially catastrophic) failure mode can be.

[0015] The present application provides improvements to such balloons and catheter devices. According to one example, an inflatable angioplasty balloon is configured to include a support structure, such as a braid, wrap, mesh, or the like, that includes a plurality of elongated fibers, which is retained by the balloon membrane, for example, by being wrapped around or otherwise disposed on the exterior of the balloon membrane. The support structure allows the balloon to retain high flexibility when inflated, allowing the balloon to curve and retain a curved shape, even at relatively high inflation pressures.

[0016] Generally, a balloon assembly includes a catheter having a predetermined length, an inflatable balloon located on the catheter, e.g., at a distal portion of the catheter, e.g., the balloon having a substantially cylindrical intermediate section between two substantially conical or other tapered end sections, and a support structure, e.g., including a plurality of inelastic fibers braided together, secured on or along the catheter at one or more locations, e.g., a first location proximal to the cylindrical section of the balloon and a second location distal to the cylindrical section of the balloon, such that inflation of the balloon reconfigures the support structure to bring the first and second locations closer together to prevent longitudinal stretching of the balloon relative to the catheter.

[0017] During balloon inflation, the increase in balloon diameter may cause the fibers of the support structure to move away from the shortest path between the first and second locations or other balloon attachments. Because the fibers of the support structure have little ability to stretch, expansion of the support structure by the balloon may involve shortening, drawing the proximal and distal ends of the balloon closer together. Thus, as the balloon expands, tension on those fibers replaces or offsets the longitudinally oriented tension. Further expansion may also cause one or more small excess circumferential folds to form in the balloon. The combination of that excess and the small longitudinally oriented wall tension allows the balloon to be flexible and / or maintain a curved shape even when fully inflated.

[0018] There are many options for polymer selection for the braid fibers, but few combine the necessary ability of the braid material to blend into the folded ends of the balloon while maintaining sufficient strength to resist the forces experienced during balloon expansion. One example of how such properties can be achieved is by forming the braid fibers from a blend of multiple polymer types. For example, a blend of polyethylene naphthalate ("PEN") fibers can provide strength to the composite braid, while nylon 6 fibers can provide a source of flux material for the composite braid. In this example, PEN / nylon 6 braid fibers are typically used in combination with standard nylon balloons.

[0019] In one example, the support structure is outside the balloon membrane and is free to move relative to the balloon surface between the fixed ends. A support structure configured as a mesh of support fibers can bend much like a braided stent by redirecting the fibers rather than stretching them. Furthermore, the support fibers may provide little resistance to the balloon bending or curvature because little energy is required to redirect such a mesh of fibers. Furthermore, increasing the number of fibers in a support structure configured as a braid, wrap or mesh can reduce or eliminate some of the balloon bulging in the spaces between the fibers, for example, by shortening the distance between the fibers and / or by further distributing the load on the fibers.

[0020] Regardless of the number of fibers used or the configuration of the support structure, the support structure may be formed from a substantially inelastic material (e.g., nylon, nitinol, Kevlar Vectran, Spectra, Dacron, Dyneema, Terlon (PBT), Zylon (PBO), Polyimide (PIM), ultra-high molecular weight polyethylene, etc.) formed into the shape of the fibers, which have sufficient flexibility to be collapsed into a low profile configuration when the balloon is deflated, for example, for stent loading and / or intravascular delivery. The support structure also has suitable flexibility to be reconfigured into a deployed configuration when the balloon is inflated for stent deployment or angioplasty procedure.

[0021] The slope or angle between the fibers of the support structure and the longitudinal axis of the balloon can be varied based on the desired mechanical properties for a particular application. For example, a relatively small slope (with the fibers initially oriented nearly parallel to the longitudinal axis of the balloon) can minimize resistance to expansion. A relatively large slope nearly perpendicular to the longitudinal axis can optimize the flexibility of the fully expanded balloon and / or impose a finite upper limit on its diameter. A large slope can also increase the ratio of length to diameter change during expansion. The slope can also be varied along the length of a single balloon. For example, a relatively small slope in the end sections can stabilize their shape and length, while a relatively large slope in the cylindrical sections can provide more flexibility.

[0022] As the balloon shortens under the influence of the support structure, a portion of the catheter within the balloon can be configured to shorten, e.g., in response to the shortening of the balloon. In one example, a supporting braid, wrap, or spring element on the catheter can prevent buckling, prevent collapse of the wire lumen, and / or assist the balloon, via its attachment to the support structure, in returning to a low profile state for removal.

[0023] According to one example, a device for performing a procedure within a patient's body is provided, the device including a tubular member having a proximal end, a distal end sized for introduction into the patient's body and a longitudinal axis extending therebetween, a non-compliant balloon carried at the distal end, the non-compliant balloon having a central region and end regions transitioning from the central region to attachment locations at the distal end, the non-compliant balloon being expandable from a contracted state to an expanded state, and a support structure having a plurality of substantially inelastic fibers braided together and extending helically around an outer surface of the balloon and including ends attached to the distal end, one or more of the fibers being movable relative to the central region of the balloon. The fibers can include a first set of fibers formed from polyethylene, e.g., polyethylene naphthalate ("PEN"), providing axial strength to the braid, and a second set of fibers formed from polyamide, e.g., nylon 6, providing a source of flux material to the braid, the flux material being meltable at processing temperatures used during assembly of the device.

[0024] According to another example, a method for performing a medical procedure is provided, the method including the steps of introducing a distal end of a tubular member into a patient's body, wherein a non-compliant balloon is provided over the tubular member in a deflated state and one or more inelastic fibers are provided on the balloon in a low-profile manner; positioning the balloon within a lesion in a body cavity; and expanding the balloon to an expanded state and reconfiguring the one or more fibers such that the balloon shortens as it expands.

[0025] According to another example, a method for manufacturing a catheter is provided, the method including the steps of providing a tubular member having proximal and distal ends sized for introduction into a patient's body, forming a balloon from a non-compliant material, the balloon including a central cylindrical section expandable to a preset size upon inflation and end sections for attachment to the distal end of the tubular member, disposing a plurality of braided fibers around the balloon when the balloon is in a deflated state, and attaching the ends of the fibers onto the end sections of the balloon. The fibers can have a preset length and are adapted to provide an axial compressive force upon inflation of the balloon to prevent foreshortening or shorten the balloon to increase flexibility of the fully inflated balloon. In one example, the fibers can be braided around the balloon such that they are free to slide or otherwise move on the exterior surface of the balloon to accommodate bending of the balloon.

[0026] The balloon and braided support structure are attached to a catheter shaft or other tubular member. Various adhesive and heat mediated attachment methods have been moderately successful in ensuring inter-component connections at the exact same location between the braid, balloon and inner catheter. As an example, a strong and precise inter-component connection can be achieved by applying heat directly, such as via a split clamp, to a precise location on a short segment of the catheter. In this example, if the necessary flux material is supplied externally (such as shrink tubing), the resulting protuberance in the device profile increases the diameter of the arterial access site. On the other hand, if some of the flux material used for the fiber, balloon and catheter connections is derived from the braid, the constituent polymers literally melt into the balloon / braid / catheter composite, making it strong, short and without protuberances.

[0027] Ideally, the inter-component connections between the braid end, balloon end, and catheter shaft are co-located, in which case the order of assembly is not important. In practice, however, it may be difficult to connect all three at the same time, in which case the balloon / braid connection is preferred as it is easier to place accurately. In one approach, the first step is to accurately and reliably connect the balloon tip and braid tip in the same location, resulting in a balloon / braid module that can be added later to the catheter portion of the device.

[0028] Once the ends of the balloon / braid assembly have been attached to their respective locations on the tubular member, any additional components or procedures may be used to provide a completed catheter. For example, if the balloon / braid assembly is attached to a relatively short segment of the catheter shaft, additional sections of the catheter may be attached to the short segment, e.g., using conventional methods and materials.

[0029] The resulting structure can provide a catheter with a reinforced balloon that can be inflated to high pressures while the braid prevents stretching and increases the flexibility of the catheter shaft. Thus, the devices and methods described herein can balance the tendency of high internal pressure within the balloon to push the ends of the balloon apart, with the tendency of high external tension of the fibers of the braid to pull the ends of the braid together. If the balloon catheter and braided balloon attachments are not securely and precisely co-located, the compressive load of the intervening inner catheter can cause off-axis displacement, kinking, component separation, and internal herniation, with potentially catastrophic consequences for the performance of the balloon. The present method can minimize such risks.

[0030] One exemplary method for achieving the desired stability of component attachment during device assembly involves attaching the ends of the balloon / braid assembly to the catheter using precisely controlled fusion with heat. Secure attachment requires sufficient polymer, obtained by melting the components themselves or an external source of the fusion material. The blended feature of the PEN / nylon braid provides strength through one set of fibers and low temperature flux through another set of fibers. The blended braid also helps identify the weld site in real time due to the change in appearance of the sets of braided fibers colored with different pigments, thereby facilitating visual confirmation that the ends are properly attached to the catheter.

[0031] Additionally or alternatively, a plastic marker band including titanium can be placed at the apex of the balloon neck, e.g., on the exterior of the balloon. Such a band can prevent expansion and / or herniation of the tapered section of the balloon, enhance identification of the neck of the conical segment of the balloon under fluoroscopic inspection, and / or provide a polymer reservoir for, e.g., heat braid / balloon and balloon / catheter attachment.

[0032] Typically, the components are added one at a time in any desired order. However, because the braid is located on the outside of both the catheter and the braid, mass production is most easily accomplished by, for example, adding the braid to a previously assembled balloon. For example, the braid can be attached to the balloon first, and then the balloon-braid assembly can be attached to a precisely identified location on the catheter, allowing for precise positioning.

[0033] According to yet another example, a method is provided for preparing a balloon catheter comprising a tubular member including a proximal end and a distal end, a non-compliant balloon located on the distal end in a contracted state, and a plurality of inelastic fibers located on the balloon in a low profile manner. The balloon is inflated to an expanded state, whereby the fibers can be reconfigured to prevent the balloon from stretching or to shorten the balloon as it expands. For example, the fibers can be braided or meshed on the balloon so as to slide freely on the outer surface of the balloon, e.g., to accommodate flexing of the balloon. When the balloon is expanded, the balloon can bend into a curved shape in the expanded state, whereby the fibers can be further reconfigured to maintain the balloon in the curved shape. For example, the fibers can slide along the outer surface of the balloon to accommodate the curved shape and / or one or more pleats can be formed in the balloon. The balloon can then be contracted to a contracted state, e.g., to be biased into the curved shape when it is next re-inflated.

[0034] In one example, the fibers can move on the outer surface of the balloon when the balloon is bent into a curved shape, so that the fibers move toward the inside of the curve and / or reduce tension on the balloon and / or tubular member, thereby facilitating the bending of the balloon without kinking. For example, the fibers can move toward the inside of the curve, thereby creating an asymmetric tension in the fibers that can exert a similar asymmetric force on the balloon to maintain the curved shape despite an externally applied bending force (that may straighten the balloon). Thus, once inflated into a curved shape, this type of balloon can exhibit "shape memory" and, even though the uninflated balloon is straight and flexible, the balloon can return to substantially the same curved shape when inflated again. This phenomenon can occur because the asymmetric braid distribution only affects the shape of the balloon when the fibers are tensioned by the expansion of the balloon. When the balloon is in its unexpanded state, the braided fibers are under only slight tension and have little effect on the shape of the balloon. In another example, the braid may be configured to remain substantially stable, e.g., evenly distributed across the exterior surface, regardless of the shape the balloon is guided to, thus allowing the fibers to easily slide across the exterior surface as the balloon changes shape under the action of an externally applied force.

[0035] For example, when a balloon is prepared for a medical procedure, the balloon may be deflated and the distal end of the catheter may be introduced into a patient and positioned within a lesion or other treatment site in a body cavity. The balloon may then be inflated within the body cavity and urged into a curved shape within the lesion. For example, a deflated balloon may be positioned within a curved body cavity and oriented so that its curved shape generally matches the curved shape of the body cavity. Thus, when the balloon is inflated, it may expand into a curved shape, thereby widening the body cavity while minimizing the risk of straightening or placing undesirable stress on the walls of the body cavity.

[0036] Other aspects and features, including the need for and uses of the present invention, will become apparent from consideration of the following description in conjunction with the accompanying drawings. [Brief description of the drawings]

[0037] It should be noted that the example devices illustrated in the drawings are not necessarily drawn to scale, emphasis instead being placed upon illustrating various aspects and features of the depicted examples. [Figure 1] Figure 1A shows a side view of an example angioplasty balloon disposed on an elongate catheter, and Figure 1B shows a side view of a support structure including a set of fibers wound around the balloon as a braid, wrap, mesh, or the like. [Diagram 2] 2A and 2B are side views of an alternative example of a balloon having a support structure, showing the support structure in a low-profile configuration when the balloon is deflated and in a deployed configuration when the balloon is inflated, respectively. [Diagram 3] 3A and 3B are side views of an inflated balloon having a support structure, showing the support structure in an inflated and curved or bent state. [Figure 4]4A and 4B show side views of an exemplary angioplasty balloon having an inflated length without a support structure on the balloon. [Diagram 5] 5A and 5B show side views of an inflated balloon with support structures in a straight and curved or bent configuration. [Figure 6] FIG. 6 shows a side view of a variation in which the support structure is made up of, for example, two or more fibers secured or connected to each other at their crossing locations. [Figure 7] FIG. 7 shows yet another variation in which the fibers are formed at a relatively large tilt or angle with respect to the longitudinal axis of the catheter. [Figure 8] FIG. 8 shows a side view of yet another variation in which three fibers are used to form the support structure. [Figure 9] Figure 9 shows yet another variation showing how fibers can be used to create regions along a balloon with different gradients or winding densities: Figure 9A is a detailed view of a first end of the balloon of Figure 9. [Figure 10] FIG. 10 shows a side view of yet another example of a balloon catheter in which the fibers of the support structure frictionally engage the outer surface of the balloon to resist straightening when inflated in a curved orientation. [Figure 11] FIG. 11 is a side view of yet another example of a balloon catheter including a support structure, where the support structure includes an asymmetric arrangement of one or more fibers that bias the balloon to bend into a curved shape when inflated. [Figure 12] FIG. 12 shows an alternative embodiment of a balloon having a support structure and an outer layer over the support structure. [Figure 13] FIG. 13 shows another example of a catheter that includes a support structure that covers a non-compliant balloon at the distal end of the catheter. [Figure 14]FIG. 14 is a photomicrograph showing a loop of braid embedded deeply into the neck of a balloon as shown in FIG. 13 to provide secure hemostatic fixation in the presence of high pressure balloon inflation.

[0038] The drawings are not intended to be limiting in any sense, and it is envisioned that various examples of the invention may be implemented in a variety of other ways, including those not necessarily shown in the drawings. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several aspects of the invention and, together with the description, serve to explain the principles of the present invention. It should be understood, however, that the invention is not limited to the precise arrangements shown. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] The following description of specific examples of the present invention should not be used to limit the scope of the present invention. Other examples, features, aspects, embodiments and advantages of the present invention will become apparent to those skilled in the art from the following description, which is for illustrative purposes one of the best modes contemplated for carrying out the present invention. As will be understood, the present invention is capable of various other obvious aspects, none of which departs from the present invention. Thus, the drawings and description are illustrative in nature and should not be regarded as limiting.

[0040] Before describing the examples, it is to be understood that the invention is not limited to particular examples described, as such may, of course, vary. Also, it is to be understood that the terminology used herein is for the purpose of describing particular examples only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.

[0041] Where a range of values ​​is given, it is understood that each intervening value between the upper and lower limits of that range, to the tenth of the unit of the lower limit, is also specifically disclosed unless the context clearly dictates otherwise. Each smaller range between any stated value or intervening value in a stated range and any other stated value or intervening value in a stated range is encompassed within the invention. The upper and lower limits of such smaller ranges may each be independently included or excluded within the range, and each range is encompassed within the invention, whether or not both or either are included in the smaller range, subject to the specifically excluded limit in the stated range. Where a stated range includes one or both of the limits, ranges excluding either or both of those included limits are also intended to be included within the invention.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, some possible exemplary methods and materials are described herein.

[0043] It should be noted that, as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, a reference to a "compound" includes a plurality of such compounds, and a reference to a "polymer" includes a reference to one or more polymers and equivalents thereof known to those skilled in the art.

[0044] In this specification, certain ranges are indicated by the term "about" before the numerical values. The term "about" is used in this specification to provide literal support for the exact numerical value following the term and for a numerical value close to or close to the numerical value following the term. In determining whether a numerical value is close to or close to a specifically stated numerical value, the close or close unstated numerical value may be a numerical value that provides a substantial equivalent to the specifically stated numerical value in the context in which it is presented.

[0045] In general, the devices and methods described herein relate to catheters for performing angioplasty and / or other intravascular procedures and / or catheters for otherwise treating a body cavity within a patient's body, including a catheter or other tubular member carrying a balloon including proximal and distal end sections (e.g., conical or other tapered end sections) and having a generally cylindrical section therebetween. The balloon also includes a support structure, such as one or more wires or other fibers, provided as braids, wraps, meshes, and the like, that are wrapped around the balloon membrane. The support structure surrounds, supports, and / or otherwise extends the entire length of the balloon, providing support while still allowing freedom of movement relative to the balloon, thereby allowing the balloon to retain high flexibility and / or allowing the balloon to bend or curve and / or resist straightening out of a curved shape, even at relatively high inflation pressures. If the balloon includes a high friction outer surface, the support structure can engage the balloon during inflation, thereby resisting the balloon changing shape from its pre-inflated shape, e.g., a curved or other non-linear shape corresponding to the body cavity, when the balloon is deployed.

[0046] During balloon expansion, the increase in the balloon diameter may cause the fibers of the support structure to pull away from one another, thereby shortening the support structure along its longitudinal axis. This shortening of the support structure draws the proximal and distal ends of the balloon closer together. Thus, when the balloon itself is fully inflated, the tension exerted on the fibers replaces or offsets the longitudinal tension in the membrane wall of the cylindrical portion of the balloon. Thus, the membrane wall of the unloaded cylindrical portion of the balloon is free to stretch differently, thereby allowing the balloon to bend and / or be highly flexible even when fully inflated.

[0047] 1A and 1B show an example of an apparatus 8, which, as will be described in more detail below, includes an angioplasty catheter 12 carrying a balloon 10 having a support structure 50, e.g., one or more wires or other fibers (two fibers 52, 54 are shown), on the exterior of the balloon. Generally, the catheter 12 includes a proximal end, e.g., a handle or hub (not shown), a distal end 12b sized and / or shaped for introduction into a patient's body, and one or more lumens 12c extending therebetween and generally defining a longitudinal axis 12d. For example, the inflation lumen 12c may be provided to communicate between a source of inflation medium, e.g., a syringe (filled with an inflation gas or a fluid such as saline) connected to a handle or hub (not shown) at the proximal end, and the interior of the balloon 10. Optionally, one or more additional lumens may be provided, such as a guidewire or instrument lumen, extending between a port at the proximal end and an outlet at the distal end (not shown).

[0048] FIGURE 1A illustrates an example of an angioplasty balloon 10 disposed on a catheter 12 (prior to placement of a support structure 50, as shown in FIGURE 1B) that is transitioned between a deflated or delivery state (not shown) and an expanded state as shown in FIGURE 1A. In the expanded state, the balloon 10 generally includes a substantially cylindrical central section 18 and proximal and distal sections 14 and 16, one or both of which are conically shaped, tapered, or otherwise transition from the central section 18 to the outer wall of the catheter 12. Each of the respective sections 14, 16 may be attached to the distal end 12b of the catheter 12, for example, at attachment locations 20, 22, using one or more of a variety of fastening mechanisms, such as adhesive bonding, fusion, sonic welding, an external collar, and the like (not shown). For example, each attachment location 20, 22 can include a relatively narrow neck, e.g., a relatively short, uniform diameter section (not shown, see, e.g., FIG. 12), for attaching the balloon 10 to the catheter 12, as described elsewhere herein.

[0049] The membrane of the balloon 10 can generally comprise a low-compliance or non-compliant material. The resulting non-compliant balloon 10 can withstand relatively high pressure inflation. As used herein, "non-compliant" means that the balloon 10 expands upon initial inflation, e.g., to a threshold pressure, to a preset expanded shape, e.g., having a substantially uniform diameter along the central section 18. As the pressure increases beyond the threshold pressure, the size and / or shape of the balloon 10 remains substantially unchanged, thereby allowing, e.g., the balloon 10 to apply pressure radially outward toward adjacent body structures surrounding the balloon 10. For example, the balloon membrane can be formed from a substantially inelastic material and configured to provide the initial expansion and internal pressure and to substantially maintain the preset expanded shape with minimal additional expansion until a burst or failure pressure is reached, e.g., in one example, between about 5 and 20 atmospheres (5-25 atm).

[0050] Thus, when the balloon 10 expands, the balloon membrane can generate a substantially equal force at all portions of the balloon 10. For example, as shown in FIG. 1A, when the balloon 10 is inflated, for example, with an inflation medium (such as an inflation gas or a fluid such as saline), the fluid contained within the balloon 10 exerts a pressure 24 against the wall of the balloon membrane. A resultant force 26 exerted by the fluid pressure 24 on the proximal section 14 of the balloon 10 is seen to project at an angle relative to the longitudinal axis of the catheter 12. A similar resultant force 28 exerted by the fluid pressure 24 on the distal section 16 of the balloon 10 is also seen to project at an angle relative to the longitudinal axis of the catheter 12.

[0051] Each of the resultant forces 26, 28 includes a longitudinally directed force component 30, 32, respectively, which are directed in opposite directions. In equilibrium, the longitudinally directed force component 30 of the proximal section 14 is equal and opposite to the sum of the reaction force 34 from the attachment between the catheter 12 and the balloon 10 and the longitudinally directed tension force 38 in the membrane wall of the balloon. Similarly, the longitudinally directed force component 32 of the distal section 16 is equal and opposite to the sum of the reaction force 36 from the attachment between the catheter 12 and the balloon 10 and the longitudinally directed tension force 40 in the membrane wall of the balloon. Furthermore, in the absence of longitudinal tension, the circumferentially directed tensile force 44 in the wall of the central section 18 generates a radially directed force 46 to balance the outward force caused by the pressure force 42.

[0052] 1B, the fibers 52, 54 of the support structure 50 are helically wound around the balloon 10, e.g., as a braid, wrap, mesh, etc., and are retained by the balloon 10, e.g., substantially permanently attached to the balloon 10 and / or catheter 12 at one or more locations. For example, when the balloon 10 is folded, rolled, or otherwise transitioned to a deflated state, the fibers 52, 54 of the support structure 50 may be wrapped around and / or otherwise surround the outer surface of the balloon 10 and coupled to the distal end 12b of the catheter 12 and / or the ends of the balloon 10, as described elsewhere herein. Optionally, a preset axial tension may be applied to the fibers 52, 54 as they are wrapped, and maintained when the ends of the fibers 52, 54 are attached to the catheter 12, e.g., to minimize the low-profile aspect of the support structure 50 and / or to restrain the balloon 10 in the deflated state.

[0053] The support structure 50, in this embodiment, is shown as two fibers 52, 54 that are staggered about the exterior surface of the balloon 10 and spirally wrapped together, e.g., in opposite helical directions, about the exterior surface of the balloon 10 such that the fibers 52, 54 overlap each other one or more times along the length of the balloon 10. In this example, the twisting forces induced by the fibers 52, 54 on the balloon 10 cancel each other out, imparting a net twist to the balloon 10 that is substantially zero.

[0054] Although the fibers 52, 54 are shown only at proximal and distal attachment locations 56, 58 as being attached to either the catheter 12 and / or the balloon 10, e.g., directly attached to the respective balloon attachment locations 20, 22, the length of the fibers 52, 54 between the attachment locations 56, 58 remains unattached to the balloon 10. For example, both ends of the fibers 52, 54 may be attached directly onto the respective neck or end portions 20, 22 of the balloon 10, e.g., by one or more of partially melting, welding, adhesively bonding, etc. the ends of the fibers. For example, FIG. 14 illustrates an exemplary cross-section of a balloon neck 20 in which the fibers of a braided reinforcement 50 are embedded deep into the material of the balloon, e.g., by partially melting some of the fibers of the braid, as further described elsewhere herein. Thus, the support structure 50 is disposed outside the balloon membrane and is free to move relative to the exterior surface of the balloon, e.g., along at least the central region 18, and optionally along the end sections 14, 16. Additionally or alternatively, the ends of the fibers 52, 54 may be attached to the distal end 12b of the catheter on the balloon membrane attachment locations 20, 22 by one or more of the following attachment methods, including wrapping the ends of the fibers 52, 54 around the catheter 12, securing the ends to collars on the catheter 12 (not shown), gluing, fusing, heat sealing or sonic fusing the ends to the ends of the catheter 12 and / or balloon membrane, etc. In one example, the fibers 52, 54 may be formed from a thermoplastic material that can be molded and / or fused, e.g., such that the ends of the fibers 52, 54 are fused together to form separate collars at each end of the balloon membrane, e.g., to prevent fraying and / or to facilitate attachment to the ends of the balloon 10. The support structure 50 may be applied to catheters of various lengths and various balloon configurations in addition to those described herein.

[0055] The mechanical properties of the balloon 10 supported by the braid of fibers 52, 54 depend on the ratio of the diameter of the braid at its maximum expansion to the diameter of the balloon at its maximum expansion. For example, if the diameter of the braid at its maximum expansion (i.e., the maximum diameter to which the braid of fibers 52, 54 can be expanded on the catheter 12, independent of the balloon 10) is less than about one hundred and thirty percent (130%) of the diameter of the balloon at its maximum expansion, the braid may limit the expansion of the balloon, especially in the central region between the ends of the balloon. This ratio may result in the balloon having a dog-bone shape at maximum expansion (i.e., a shape that is larger toward the ends than in the central region), and the most restricted central portion does not reach a full unrestricted diameter. If the diameter of the braid at its maximum expansion exceeds about one hundred and fifty percent (150%) of the diameter of the balloon at its maximum expansion, the balloon may not be able to form a smooth arc of substantially uniform curvature, especially at high degrees of bending. Instead, the balloon may form a series of relatively straight segments connected by sharp bends. It may therefore be desirable to maintain the ratio of maximally expanded braid diameter to balloon diameter between about one hundred and twenty percent and one hundred and sixty percent (120-160%), or between about one hundred and thirty percent and one hundred and fifty percent (130-150%).

[0056] Alternatively, although two fibers 52, 54 are shown, other variations of the support structure 50, as well as other examples described elsewhere herein, may use three or more fibers, for example, one or more sets of fibers wound in opposite directions and configured into a braid, wrap, mesh, etc., including, for example, between about two and two hundred (2-200), between ten and eighty (10-80), between twenty and fifty (20-50) fibers in total or in each direction, depending on the application. For example, for smaller balloons, 24-48 fibers may be used, for medium balloons, 36-72 fibers may be used, and for larger balloons, 48-96 fibers may be used. FIG. 13 shows one example of a device 308 including a balloon 310 attached to a catheter 312, with a support structure 350 including fibers braided and attached to the end 320 of the balloon 350 and to the catheter shaft.

[0057] The catheter 12 itself generally has a length between the proximal and distal ends 12b in the range of between about eighty and one hundred centimeters (80-150 cm) and an outer diameter between about one and three millimeters (1-3 mm or 3-9 Fr). The balloon 10 has a spindle shape, an overall length of between about ten and one hundred millimeters (10-100 mm) and an expanded diameter along the central region 18 of between about two and twelve millimeters (2-12 mm). The balloon 10 may be attached to the distal end 12b of the catheter 12 adjacent a tapered or other atraumatic distal tip. The balloon 10 may typically be formed from a low-compliance thermoplastic material, such as medium to high durometer PEBAX, nylon or PET.

[0058] In general, regardless of the number of fibers used or the configuration of the support structure 50, the fiber or fibers can be formed from a substantially inelastic material such that each fiber does not substantially axially stretch or elongate, break, or fail during normal use conditions. For example, the fiber or fibers can be formed from a variety of materials, such as nylon, nitinol, Kevlar Vectran, Spectra, Dacron, Dyneema, Terlon (PBT), Zylon (PBO), polyimide (PIM), ultra-high molecular weight polyethylene, or polyester. The fiber or fibers can be formed into substantially round or flat, solid or hollow, ribbons, wires, or other filaments, such as by extrusion, weaving or knitting finer filaments, machining, molding, etching, material deposition, or the like. For example, the diameter or other maximum cross-sectional dimension of the fiber can be between about 0.001 inches and 0.010 inches, such as between about 0.002 inches and 0.003 inches. The resulting fibers can be suitable for flexibility to be folded into a low profile configuration when the balloon 10 is collapsed to its contracted state, for example, for stent crimping or loading and / or intravascular delivery, and the support structure 50 can also be suitable for flexibility to be reconfigured into an deployed configuration when the balloon 10 is inflated to its expanded state, for example, for stent deployment or angioplasty, without substantial plastic or elastic stretching of each fiber along its length.

[0059] In one example, the fibers include a first set of fibers formed from a polyethylene, e.g., polyethylene naphthalate ("PEN"), which provides axial strength to the braid, and a second set of fibers formed from a polyamide, e.g., nylon 6, which provides a source of flux material for the braid. For example, the first set of fibers may be formed entirely from a polyethylene material and the second set of fibers may be formed entirely from a polyamide. Alternatively, the fibers may include additional materials, as desired, as described elsewhere herein. For example, a coating or other material may be added to the fibers that does not substantially change the mechanical properties of the fibers in each set.

[0060] For example, a first set of fibers may be configured to provide a desired tensile strength to the support structure, and a second set of fibers may be configured to provide a flux material to facilitate attachment of the support structure to a balloon. For example, polyamide fibers may melt at processing temperatures used during assembly of the device, e.g., to fuse the ends of the fibers to one another and / or to the ends of the balloon, as described elsewhere herein. For example, as shown in FIG. 14, polyamide fibers may facilitate embedding the ends of the fibers within the balloon, thereby securing the fibers without the need for additional materials and / or components.

[0061] In one example, the number of fibers in each set can be selected to provide the desired reinforcement and available flux material, for example, at least about 50% of the fibers are formed from PEN, or at least about 60% of the fibers are formed from PEN, or at least about 70% of the fibers are formed from PEN, or at least about 80% of the fibers are formed from PEN, with the remaining fibers being formed from a polyamide, such as nylon 6. The fibers in each set can be substantially uniformly distributed around the periphery of the support structure such that the resulting braided mesh can have substantially uniform mechanical properties around the periphery and along the length of the mesh.

[0062] Optionally, one or more fibers of the support structure 50 may be porous, for example, such that one or more compounds, e.g., one or more therapeutic compounds, are incorporated within the pores of the one or more fibers. Alternatively, one or more fibers may be coated with such compounds and / or other materials, e.g., radiopaque or other materials that facilitate imaging the support structure using external imaging when the catheter 12 is introduced into the patient's body. For example, to enhance radiopacity, some of the fibers may include iodine, metal powder, e.g., titanium powder, etc. Alternatively, some of the fibers may be formed entirely of metal fibers, e.g., gold or platinum, or other materials, to enhance radiopacity. Additionally or alternatively, one or more compounds may be coated, embedded, or otherwise incorporated into the exterior surface of the balloon 10. When the balloon 10 is brought to a deflated state, the support structure 50 around the balloon 10 can, at least in part, protect the compound, e.g., from abrasion and / or minimize exposure, until, e.g., the balloon 10 is inflated and the fibers 52, 54 of the support structure 50 move apart to expose the outer surface of the balloon 10, after which the compound can be released into the surrounding tissue and / or body cavity.

[0063] A support structure 50 configured as a mesh of support fibers bends in much the same manner as a braided stent, e.g., by redirecting rather than stretching the fibers. Moreover, because only little energy is required to redirect such a mesh of fibers, the support fibers provide little resistance to the curvature or bending of the balloon 10. Furthermore, if the number of fibers in the support structure 50 configured as a braid, wrap, or mesh is increased, bulging of the portion of the balloon in the spaces between the fibers can be reduced or eliminated, e.g., by shortening the distance between the fibers and / or by further distributing the load on the fibers, as described elsewhere herein. For example, as shown in FIG. 10, a catheter 112 can be provided that includes a balloon 110 carrying a support structure 150 that includes between about two and two hundred (2-200) fibers 152 wound in a helical mesh around the balloon 110. The resulting braid can provide a geodesic effect that helps secure the balloon 110 in a preset configuration or other curved configuration during inflation.

[0064] Additionally, the support structure 50 may be attached at its proximal and distal attachment locations 56, 58 such that when the balloon 10 is inflated, the support structure 50 has minimal or substantially no effect on the pressure-induced forces acting on the balloon 10, as described elsewhere herein. In operation, as the balloon 10 is expanded to an expanded state as shown in FIG. 1B, thereby causing the support structure 50 to reconfigure itself, the fibers of the support structure 50 may exert tension along each of their respective longitudinal axes, as shown by the tensile reaction forces 60, 64 shown in FIG. 1B. Each of the reaction forces 60, 64 may include a force component that is partially oriented in the longitudinal direction, as shown by the longitudinal reaction forces 62, 66, respectively. These reaction forces 62, 66 pull the proximal and distal attachment locations 56, 58 of the support structure 50 toward one another, e.g., generally parallel to the longitudinal axis 12d of the catheter 12, thereby pulling the attachment locations 20, 22 of the balloon 10 toward one another and axially compressing at least the central region 18 of the catheter 12 (which is designed to reversibly shorten) between the two attachment locations 56, 58.

[0065] Thus, when the balloon 10 expands and is shortened by the support structure 50, the longitudinal tensions 38, 40 in the membrane wall of the balloon 10 are relieved, so that they no longer resist the longitudinal force components 30, 32. The expansion of the balloon 10 lengthens the helical path of the fibers of the support structure 50, so that the fibers become taut and pull or draw the ends of the balloon 10 together. This allows the balloon 10 and the support structure 50 to retain flexibility in bending or curving, for example, to conform to the inner wall of a blood vessel even when the balloon 10 is inflated to a relatively high pressure. This is even more noticeable when compared to a balloon 10 that does not have such a support structure 50, because such a balloon 10 straightens out when inflated and cannot bend or curvature with the same degree of flexibility.

[0066] In the presence of the support structure 50, there is no fixed relationship between the tension in the wall of the balloon 10 along a first direction and the tension in the wall along another direction because the longitudinal component of force along the fibers of the support structure 50 on the balloon 10 replaces or overcomes the longitudinal component of tension along the balloon wall, such that the longitudinal component along the balloon 10 is reduced or falls to or approaches zero. Thus, a longitudinally unloaded wall offers little resistance to the curvature or bending of the balloon 10.

[0067] In one example, the catheter 12 further includes "shock zones" (not shown), for example on the distal end 12b between the ends of the balloon 10, that allow the catheter 12 to reversibly shorten as the balloon 10 shortens. This allows for relatively greater longitudinal redundancy, greater differential stretch between opposing walls, and / or reduced resistance to bending. These shock zones may be spring loaded (e.g., via various biasing mechanisms not shown, such as perforated Nitinol hypotubes, compression springs, etc.), which may facilitate the balloon 10 returning substantially to its initial length as it deflates. Alternatively, the distal end 12b of the catheter 12, for example between the attachment locations 20, 22 of the balloon 10, may have a high degree of flexibility, for example between the attachment locations 20, 22 of the balloon 10, which may allow the distal end 12b to transition from a generally linear to a helical or other nonlinear shape as the balloon 10 shortens, as described elsewhere herein, for example as shown in FIG. 3A.

[0068] 2A and 2B, another example of a device 8 including a catheter 12 and a balloon 10 having a support structure 50 is shown. In FIG. 2A, the balloon 10 is shown in its deflated or delivery state and the support structure 50 in its low-profile embodiment, while in FIG. 2B, the balloon 10 is shown in its expanded state and the support structure 50 in its deployed embodiment. In this example, the support structure 50 includes a single fiber 54 that is attached to the balloon 10 and / or catheter 12 at proximal or distal attachment locations 56, 58 and wrapped or wound around the outer surface of the balloon 10. In this example, a single fiber 54 is shown for clarity, but multiple fibers may be used, as in other examples herein. The resulting low-profile embodiment has an overall retracted length of L1, as shown in FIG. 2A, and the fiber 54 may form an initial fiber braid angle α with respect to the longitudinal axis 12d of the catheter 12. As shown in FIG. 2B, when the balloon 10 is inflated, the portion of the catheter 12 within the balloon 10 shortens as the diameter of the helical path taken by the fibers 54 increases, forming an expanded and reconfigured fiber braid angle α+δ with respect to the longitudinal axis 12d of the catheter 12 that is greater than the initial fiber angle α. Because the fibers 54 are formed from a substantially inelastic material, the fibers 54 themselves cannot stretch as their helical path expands, and tensile stresses within the fibers 54 increase. This allows the balloon 10 to further shorten in length due to its support structure 50, and to retain flexibility due to the relief of tension along the membrane wall. The inflated balloon length L2 is shown as being shorter than the initial deflated balloon length L1.

[0069] 3A and 3B, yet another example of a device 8' when inflated and curved or bent is shown, including a catheter 12' including an inflated balloon 10' having a support structure (not shown for clarity) thereon. As the balloon 10' expands and is shortened by its support structure, as shown in FIG. 3A, a portion 12e' of the catheter 12' passing through the interior of the balloon is compressed longitudinally, allowing the balloon 10' to form one or more circumferentially oriented pleats 60' along its length. The pleats 60' allow differential stretching between opposing walls of a cylindrical central section 18' of the balloon 10', thereby allowing the balloon 10' to bend or curve, for example, as shown in FIG. 3B (such balloons 10' are not normally able to bend or curve due to the stiffness typically imparted to non-compliant balloons when expanded, as described elsewhere herein). As shown, when the balloon 10' is inflated and straight (FIG. 3A), the opposing side walls S1, S2 of the balloon 10' are substantially equal, but when the balloon 10 is curved or bent (FIG. 3B), the length S1 of the first side wall increases and the length S2 of the opposing second side wall decreases, such that the length S1 of the first side wall forms the outer radius of the curved balloon 10' and the length S2 of the second side wall forms the inner radius, S1>>S2. Once the balloon 10' is curved or bent, the support structure allows the balloon 10' to remain curved or bent, unlike conventional high pressure balloons.

[0070] As a further illustration of the effect of the support structure on an inflated balloon as described herein, Figures 4A and 4B show a side view of an exemplary conventional angioplasty balloon 70 having an inflated length L1, without a support structure integral with the balloon 70. Figure 4B shows minimal curvature or bending of the balloon 70 relative to a straightened configuration when an off-axis force is applied to the balloon 70, such as when the balloon 70 is inflated in a curved vessel. This is in contrast to a catheter 12 (similar to the device 8 shown in Figures 2A and 2B, or other examples herein) having a support structure 50 integral with the balloon 10, as shown in the side view of Figures 5A and 5B. Although a single fiber 54' is shown as being helically disposed on the balloon 10, this is for illustrative purposes only, and any number of additional fibers may be utilized in the support structure, as described elsewhere herein.

[0071] When inflated at a high pressure similar to that of the unsupported balloon 70, the balloon 10 with the support structure 50 provides redundancy that allows the overall length of the balloon to be slightly shortened during inflation, relieving tension at the balloon 10 and at the distal end 12b of the catheter 12 within the balloon 10, and allowing differential stretching between the inside and outside of the balloon 10 when deployed in a curved body lumen. For example, the unsupported balloon shown in FIG. 4A has a length L1 that does not change substantially during inflation. In contrast, the balloon 10 with the support structure 50 has a contracted length similar to L1, but upon inflation, can have a length L2 that is shorter than the initial length L1. Furthermore, the resulting balloon 10 of FIGS. 5A and 5B can substantially maintain its flexibility when curved or bent, as shown in the side view of FIG. 5B, unlike the unsupported balloon 70, which resists bending as shown in FIG. 4B.

[0072] In yet further variations, the support structure may be configured in a variety of different configurations on the balloon. FIG. 6 shows a side view of one example where the support structure is comprised of two or more fibers, such as two fibers 80, 82, shown wound in opposite directions relative to one another around the balloon 10, that are connected or otherwise coupled to one another at crossover locations 84. For example, the fibers 80, 82 may be knotted, secured, tethered, bonded, attached, or otherwise coupled to one another at the crossover locations 84 where the fibers overlap or otherwise cross over one another as they spiral around the balloon 10, such that the fibers 80, 82 may rotate or twist about the crossover locations 84 when the balloon 10 is expanded. In one example, the fibers 80, 82 may be coupled at each of the crossover locations 84, or alternatively, the fibers 80, 82 may be coupled at only some of the crossover locations 84, such as every other crossover location or every other crossover location. Although two fibers 80, 82 are shown, a single fiber or more than two fibers may be utilized, as described elsewhere herein.

[0073] 7 shows yet another variation in which the fibers 80, 82 are formed to define a relatively high tilt or angle with respect to the longitudinal axis 12d of the catheter 12. As the balloon 10 expands to its expanded state, the support structure can define a relatively high density structure due to the additional turns that the fibers 80, 82 undergo. A support structure with a relatively low tilt or wrap angle can provide a balloon assembly with high flexibility, while a relatively high tilt or wrap angle can provide an increased ratio of length change to diameter when the balloon 10 expands, as compared to, for example, the example shown in FIG. 6.

[0074] 8 shows a side view of yet another example using three fibers 80, 82, 84 to form a support structure. Optionally, in this example, as in the other examples, the fibers 80, 82, 84 may be knotted, secured, attached, or otherwise connected to one another at one or more crossing locations, or the individual fibers may simply be one above the other without being connected to one another, for example in an over-under braided or other pattern.

[0075] FIG. 9 shows yet another example illustrating how the fibers 80 of the support structure can be used to create regions along the balloon 10 having different tilts, winding densities, and / or other mechanical properties. For example, a first portion 90 of the balloon 10 can have fibers 80 that define a relatively smaller tilt or winding angle relative to the longitudinal axis 12d of the catheter 12, as shown in FIG. 9A. A second portion 92 of the balloon 10 can have fibers 80 that define a relatively larger tilt or winding angle relative to the longitudinal axis 12d of the catheter 12, as shown, compared to the first portion 90. Both this example and other examples described herein can incorporate one or more regions with different tilt fiber angles depending on the desired bending or other mechanical properties of the balloon 10. Additionally, the support structure can be configured to have two or more regions with different tilts or winding angles, each of which can optionally vary in length along the balloon 10 as well.

[0076] Optionally, in any of the examples, one or more layers can be provided on the support structure (not shown). For example, FIG. 12 shows a device 108 including a relatively thin outer layer 130 of elastic material provided on a support structure 50 attached to a catheter 12, e.g., at or beyond the ends 20, 22 of the balloon 10. The outer layer 130 can be formed of a lubricious material or can include a lubricious coating on one or both of its inner and outer surfaces. Thus, during the expansion of the balloon 10 and the resulting reconfiguration of the support structure 50, the outer layer 130 can provide a transition between the support structure 50 and a stent or other prosthesis (not shown) mounted on the balloon 10. As one or more fibers of the support structure change angle and / or otherwise reconfigure during expansion, torsional or other circumferential forces are absorbed by the outer layer 130 and not transmitted to the prosthesis, thereby maintaining the prosthesis in its original shape during expansion.

[0077] In use, any of the devices herein can be used to perform a medical procedure within a patient's body. For example, referring to device 8 shown in FIGS. 1A and 1B, an angioplasty procedure can be performed to dilate or otherwise treat a stenosis or other lesion within the patient's vasculature. With balloon 10 in a deflated state (not shown), distal end 12b of catheter 12 can be introduced into the patient's vasculature, e.g., from a percutaneous entry site in the patient's femoral vessel, carotid artery or other peripheral vessel, similar to conventional interventional procedures, e.g., with a guide catheter, guidewire and / or other instrument (not shown). Distal end 12b is advanced and / or otherwise guided from the proximal end of catheter 12 to position balloon 10 across the lesion. Balloon 10 and support structure 50 can be flexible enough to advance through tortuous anatomy, e.g., within a lesion located in a curved or other non-linear vessel.

[0078] Once positioned within the lesion, the balloon 10 can be inflated to transition the balloon 10 to an expanded state, thereby reconfiguring the support structure 50 to its deployed configuration. Once the balloon 10 is positioned within a curved lesion, the support structure 50 can substantially maintain the balloon 10 in a curved shape corresponding to the lesion. For example, the support structure 50 can shorten and / or otherwise reconfigure the balloon 10 to, for example, create one or more pleats within an inner radius and / or other regions of the balloon 10, thereby providing sufficient flexibility to conform to the curved shape of the lesion despite the non-compliant material of the balloon 10.

[0079] Optionally, prior to a procedure, the balloon 10 can be prepared so that it exhibits "shape memory," e.g., to bias the balloon 10 into a desired curve or other shape. For example, immediately prior to a procedure, the balloon 10 can be inflated to a fully expanded (e.g., substantially straight) state while being bent into a desired curved shape (e.g., a simple curve having a desired radius of curvature, or a more complex shape, if desired), thereby further reconfiguring the support structure 50 to maintain the balloon 10 in the curved shape. For example, the fibers 52, 54 can slide along the outer surface of the balloon 10 and / or form one or more pleats in the balloon 10 to conform to the curved shape. The balloon 10 can then be re-deflated to a deflated state.

[0080] Once expanded to a curved shape, the balloon 10 will assume substantially the same shape upon re-inflation despite intermittent deflation and reconfiguration (in the deflated state). A new shape (in the inflated state) can be imprinted on the balloon as desired, for example, by forcing an inflated balloon to bend, or by bending an uninflated balloon and then re-inflating the balloon while maintaining the new shape.

[0081] This feature can be useful when endoluminal instrumentation must traverse a curved path. For example, it is often difficult to induce a conventional dilator to bend sufficiently to allow the sheath to pass around bends, bifurcations, and strictures. In these situations, a fixed curvature of the dilator can be somewhat useful if it is not too difficult to introduce through a straight segment of the body cavity or straight segment of the sheath. An uninflated shape memory balloon can be flexible enough to be easily inserted into an obstructive lesion just beyond the tip of the sheath where balloon expansion induces bending. The sheath can then be advanced beyond the obstructive lesion into the lumen of interest with or beyond the appropriately sized balloon.

[0082] One potential advantage of the balloon 10 and support structure 50 described herein is that the support structure 50 may promote a generally uniform expansion of the balloon 10. For example, unlike a typical non-compliant balloon, which tends to expand to a maximum diameter in one or two places (e.g., both ends) before propagating downward (e.g., toward the center of the balloon), the support structure 50 carried by the balloon 10 allows the balloon 10 to expand generally uniformly throughout its length during inflation.

[0083] Additionally or alternatively, the fibers 52 of the support structure 50 can decouple the deploying balloon from the inner surface of the artery against which the balloon 10 is inflated, or from the inner surface of a stent (not shown) if a stent is held on the balloon 10. This effect can protect the artery from kinking and dissection, as the balloon 10 is free to expand within the fibers 52 around the support structure 50 when no stent is present. This effect can increase the security of the stent attachment, for example, as the balloon 10 is free to slide within the support structure 50 as it deploys and expands, thereby minimizing torsional forces on a stent held around the support structure 50. In contrast, conventional angioplasty balloons may not securely attach to a stent unless a non-compliant balloon limits the rotation required to open. Such a configuration may facilitate the delivery of multiple independent stents carried by a single balloon, for example, as disclosed in Application No. 14 / 133,542, filed December 18, 2013, the entire disclosure of which is expressly incorporated herein by reference.

[0084] In an alternative example, optionally, the outer surface of balloon 10 may be configured to enhance engagement between support structure 50 and balloon 10 during expansion, e.g., to secure balloon 10 in a curved shape within a similarly shaped lesion. For example, the outer surface of balloon 10 may include a high friction treatment or coating, such that support structure 50 may frictionally engage balloon 10 during expansion to maintain the curved shape and resist straightening of balloon 10 during expansion (which may otherwise create undesirable stresses in the vessel through which balloon 10 is expanded).

[0085] For example, FIG. 10 shows a catheter 112 including a balloon 110 and a support structure 150, constructed generally similarly to other examples herein. The support structure 150 includes a plurality of substantially inelastic fibers 154 woven into a braid. While the illustrated example includes only a single fiber 154 wound in each helical direction, a denser braid or mesh may be provided, for example, including 2-10 fibers wound in each direction, if desired. Inflation of the balloon 110 exerts an outward force on the fibers 154 of the support structure 150, thereby tensioning the fibers 154 between their attachment points proximal and distal to the balloon 110. This tension causes the fibers 154 of the support structure 150 to slightly dig into the outer surface 110a of the balloon 110, for example, forming a slight quilting of the balloon surface (highlighted prominently in FIG. 10).

[0086] Optionally, the outer surface 110a of the balloon 110 has a high friction coating, texture, or other features to enhance engagement between the fibers 154 and the balloon 110. The resulting friction between the fibers 154 and the balloon 150 can substantially lock both in place when the balloon 110 is inflated, e.g., within a curved or other shaped lumen, thereby resisting bending or subsequent straightening of the balloon 110 and the distal end 112b of the catheter 112 within the balloon 110. Optionally, the distal end 112b of the catheter 112 can be configured to accommodate a curved shape while keeping a working lumen 112c through the catheter 112 open, e.g., to receive one or more instruments therein. The frictional engagement between the fibers 154 and the balloon 110 allows the distal end 112b of the catheter 112 to transition from a flexible to a rigid state, which can be useful in interventional procedures that require abrupt changes in direction from the access site to the intervention site.

[0087] 11, in another example, a catheter 212 is provided in which a support structure 250 can bias a balloon 210 to expand into a predetermined curved shape upon inflation. The catheter 212 generally includes a proximal end (not shown), a distal end 212b, an operating lumen 212c, an inflation lumen 212f, and a longitudinal axis 212d, similar to other examples herein. Additionally, the catheter 212 includes a balloon 210 and a support structure 250, which can be configured similar to other examples herein. As shown, the support structure 250 can include a single fiber 254 asymmetrically disposed about the outer surface 210a of the balloon 210, for example, the fiber 254 defines a plurality of circumferential loops 254a that extend around the outer surface of the balloon 210 and are connected to each other by a single longitudinal or axial segment 254b between adjacent loops 254a, and the longitudinal segments 254b are aligned with each other along one side of the balloon 210.

[0088] As a result of this configuration of the fibers 254, the fibers 254 are placed in tension when the balloon 210 is inflated, exerting a greater pulling force on one side of the balloon 210 than on the other side, bending the catheter 212, for example, around the side that includes the longitudinal segment 254b, as shown in Figure 11. Thus, the balloon 210 can be inflated after being positioned within a curved lesion, and the fibers 254 can maintain the distal end 212b in a curved orientation when the balloon 210 is inflated. Alternatively, the balloon 210 can be expanded to change the distal end 210 from a substantially straight configuration to a curved configuration, for example, to facilitate access to a body cavity or other vessel within the patient's body. For example, the distal end 212b may be curved or bent to direct the outlet 212e of the working lumen 212c toward a branch or other vessel, thereby allowing a guidewire, catheter and / or other device to be advanced from the working lumen 212c into the vessel of interest, for example to facilitate branch catheterization.

[0089] Optionally, the catheter 212 can include one or more markers (not shown), e.g., formed from a radiopaque, echogenic, or other material, at desired locations on the distal end 212b, the balloon 210, and / or the fiber 254 to facilitate identifying the location and / or orientation of the balloon 210 and the fiber 254 using external imaging, e.g., fluoroscopy, ultrasound, etc. For example, markers can be provided asymmetrically positioned on the balloon 210, e.g., aligned with the longitudinal segment 254b of the fiber 254, to facilitate identifying the orientation of the fiber 254 within the body vessel. To this end, a user can rotate the catheter 212 from its proximal end to rotate the balloon 210 and the fiber 254 until the longitudinal segment 254b is oriented near the bifurcation or bend where the distal end 212b is to be led.

[0090] In another option, a stent or other prosthesis (not shown) may be carried on balloon 10 by any of the catheters herein, such as catheter 12 of FIGS. 1A and 1B, and the prosthesis may be expanded and / or otherwise deployed within the lesion when balloon 10 is expanded.

[0091] Optionally, balloon 10 (of any examples herein) may be deflated and inflated one or more times, for example after being positioned within a lesion and / or one or more other locations within the patient's vasculature. Once the procedure is complete, balloon 10 can be deflated to a deflated state to reconfigure support structure 50 to a low-profile aspect, and catheter 12 can be removed from the patient's body.

[0092] The application of the above-described devices and methods is not limited to angioplasty balloons, but may include application to a variety of other inflatable balloons. Variations of the above-described assemblies and methods for carrying out the invention, combinations between the various variations as may be practiced, and variations of aspects of the invention that are obvious to those skilled in the art are intended to be included within the scope of the claims.

Claims

1. A method for manufacturing a balloon catheter, A step of providing a balloon formed from a non-compliant material, wherein the balloon includes a central region and end regions at both ends of the central region, and each end region includes a relatively narrow neck portion. A step of arranging a plurality of inelastic fibers around the balloon, wherein the fibers extend spirally around the outer surface of the balloon between the neck portions, A step of attaching both ends of the fiber to the respective neck portions, wherein the fiber is left in a state where it can move freely relative to the outer surface along at least the central region of the balloon, A method characterized by comprising the step of attaching the neck portion and the end of the attached fiber to the distal end of a tubular member at first and second spaced-apart attachment positions.

2. In the method according to claim 1, A method further comprising the step of weaving the fibers into a tubular mesh before arranging the fibers around the balloon.

3. In the method of claim 2, A method characterized in that the first and second fiber sets are distributed substantially uniformly around the outer periphery of the mesh.

4. In the method according to claim 1, A method characterized in that the fiber comprises a first fiber set formed from polyethylene and a second fiber set formed from polyamide.

5. In the method according to claim 4, A method characterized in that the first fiber set contains polyethylene naphthalate ("PEN") and the second fiber set contains nylon 6.

6. In the method according to claim 4, A method characterized in that the first fiber set is formed entirely from polyethylene, and the second fiber set is formed entirely from polyamide.

7. In the method according to claim 4, A method characterized in that the attachment of both ends of the fiber includes welding the ends to their respective neck portions, providing flux material with the second fiber set, and embedding the ends at the neck portion into the balloon material.

8. In the method of claim 7, A method characterized in that the end of the second fiber set is partially melted in order to embed both ends of the fiber into their respective neck portions.

9. In the method according to claim 1, A method for providing a balloon mesh assembly, characterized in that both ends of the fiber are attached to their respective neck portions, and the ends of the balloon mesh assembly are attached to the precise positions on the tubular member.

10. In the method according to claim 9, A method characterized in that the ends of the balloon mesh assembly are attached to the tubular member at a precise position by directly applying heat, for example, via a split clamp.

11. In the method according to claim 1, A method characterized in that the tubular member includes a relatively short segment of a catheter, and the method further includes the step of attaching one or more additional tubular members to the segment.

12. A device for performing procedures inside a patient's body, A tubular member having a proximal end, a distal end sized to be introduced into the patient's body, and a longitudinal axis extending between them, A non-compliant balloon supported at the distal end, having a central region and an end region that transitions from the central region to an attachment position on the distal end, and being expandable from a deflated state to an expanded state, A support structure having a plurality of substantially inelastic fibers, wherein the fibers are formed as a braid extending spirally around the outer surface of the balloon, and include both ends fixedly attached at their respective mounting positions, and the intermediate regions of the fibers are movable relative to the central region of the balloon, The device is characterized in that the fiber comprises a first fiber set containing polyethylene and a second fiber set containing polyamide.

13. In the device according to claim 12, The first fiber set is a device characterized by being entirely made of polyethylene.

14. In the device according to claim 13, The second fiber set is characterized by being formed entirely from polyamide.

15. In the device according to claim 12, The device is characterized in that the first fiber set contains polyethylene naphthalate ("PEN") and the second fiber set contains nylon 6.

16. In the device according to claim 12, The device is characterized in that both ends of the fiber are welded to the mounting position, and the second fiber set provides flux material to embed both ends into the balloon material at the mounting position.

17. In the device according to claim 12, The device is characterized in that the mounting position includes a relatively thin neck portion in the end region, and both ends of the fiber are welded to the neck portion.

18. In the device according to claim 17, A device characterized in that both ends of the second fiber set are partially melted, and both ends of the fiber are embedded in their respective neck portions.

19. In the device according to claim 12, A device characterized in that the first and second fiber sets are distributed substantially uniformly around the outer circumference of the support structure.

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