Expandable medical balloon having a variable diameter and related methods

Abstract

The medical device includes an inflatable medical balloon formed from a compliant material having one or more fibers embedded therein, wherein the one or more fibers can be braided or can form intersections having a first, smaller angle in a first, smaller inflated state of the medical balloon and a second, larger angle in a second, larger inflated state of the medical balloon. A catheter shaft having opposed ends can be connected to a tubular member for forming the inflatable medical balloon. The outer diameter of the tubular member can be in substantially the same plane as the outer diameter of the opposed ends of the catheter shaft. A guide wire tube can pass through the catheter shaft and the tubular member and can be connected to the distal tip of the catheter shaft. A proximal hub includes a first port for supplying inflation fluid to the catheter shaft and a second port adapted to receive a guide wire passing through the catheter shaft.

Description

Background Art

[0001] Medical balloons are often used to open or expand the incised body space restricted by rigid tissues such as stenosis, scar or calcified areas. In these applications, medical balloons with high operating and burst pressures may be required. For example, an inflatable balloon is used in angioplasty, a procedure in which the balloon can be used to expand a stenotic lesion. In these applications, it is desirable to make the outer wall of the inflatable balloon as thin as possible while still maintaining the required pressure level or burst strength. It is also desirable for the balloon to exhibit a high degree of puncture resistance.

[0002] Medical balloons are generally referred to as compliant, non-compliant, and semi-compliant. Balloon compliance is a term used to describe the change in the diameter of a balloon as a function of pressure. Low-pressure compliant medical balloons are typically formed from elastomers such as latex, polyurethane, and other thermoplastic elastomers. Low-pressure compliant medical balloons can expand by more than 100% when inflated. Compliant medical balloons are typically used for fixation and closure.

[0003] Instead, a high-pressure non-compliant balloon expands little, if at all, when pressurized from its nominal diameter to its rated burst pressure. The rated burst pressure is the maximum pressure at a statistical 95% confidence level at which 99.9% of the total number of balloons do not burst. High-pressure non-compliant balloons can have a rated burst pressure of up to 20 atmospheres. Generally, high-pressure non-compliant balloons are formed from relatively inelastic materials such as oriented highly crystalline polyethylene terephthalate (PET) film. Such PET films provide high tensile strength and can be used to form balloons with thin walls having a high burst pressure. However, balloons formed from PET and similar materials, which have relatively high strength for their wall thickness, tend to be more vulnerable to puncture. Balloons formed from PET also tend to be stiffer than balloons made from other more compliant materials. The stiffness of a deflated balloon directly affects its "trackability," i.e., its ability to pass through sharp turns or bifurcations in a blood vessel or body cavity that the balloon must traverse. Balloons with more flexible walls generally provide better trackability.

[0004] In some applications, compliant balloons may be preferred over non-compliant balloons. Compliant balloons tend not to be as stiff as non-compliant balloons and, as a result, provide better trackability. Compliant balloons can also provide better puncture resistance than non-compliant balloons. Thus, clinicians may prefer compliant balloons over non-compliant balloons in procedures where a balloon that expands to varying diameters is needed, the balloon must pass through small-diameter blood vessels, and / or the balloon must pass through a tortuous path. In some examples, compliant dilation balloons can be used to pre-dilate a stenosis prior to stent placement. Clinicians may also prefer compliant dilation balloons over non-compliant balloons for stent placement and / or for post-stent dilation.

[0005] To reduce the profile of the balloon, the expandable balloon can be formed of a pleated wall. When the balloon is deflated (i.e., before and after inflation), these pleats are folded, rolled, and / or rounded about the major axis of the balloon. As a result, the thinner the wall material of the balloon, the smaller the diameter of the balloon catheter assembly. The smaller diameter can be used with a smaller introducer and can reduce patient discomfort. The smaller diameter also facilitates passage of the deflated balloon through narrow vasculature, lumens, or cavities of the body prior to placement.

[0006] Accordingly, there is a need for an inflatable medical balloon that can achieve the benefits of a high level of compliance, puncture resistance, high burst pressure, and a thin wall while providing a variable diameter for expansion purposes. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The object of the present disclosure is to provide an inflatable medical balloon with a variable diameter (meaning that the medical balloon has different diameters at different inflation pressures). The medical balloon may comprise a compliant tubular member having fibers embedded in the wall of the tubular member. The fibers may be of a pattern woven at a constant small winding angle or a variable winding angle along the length of the tubular member. The proximal and distal ends of the compliant tubular member forming the medical balloon may be directly fused to opposite ends of a catheter shaft, the ends of the catheter shaft having the same outer diameter as the tubular member and thus being in the same plane as it in the non-inflated state, eliminating variations and, alternatively, reducing the outer shape of the resulting instrument. The medical balloon may be inflated via a port associated with a proximal hub connected to the catheter shaft. In the deflated state or when no pressure is applied, the compliant tubular member may thus be in the same plane as the catheter shaft. When the compliant tubular member expands, the embedded fibers allow the compliant material forming the medical balloon to radially expand in a controlled manner as the pressure increases and as the fibers resist expansion.

Means for Solving the Problems

[0008] According to one aspect of the present disclosure, a medical instrument is provided. The medical instrument includes an inflatable medical balloon with a variable diameter that includes a super-compliant material having one or more fibers embedded therein.

[0009] In one embodiment, the super-compliant material is selected from the group including silicone, polyurethane, hydrogel, or any polymer having an extensibility greater than 30% and a Young's modulus of less than 100 MPa. In this or other embodiments, the one or more fibers include one or more woven fibers and / or the one or more fibers include intersections of one or more fibers having a first smaller angle in a first smaller inflated state of the medical balloon and a second larger angle in a second larger inflated state of the medical balloon.

[0010] The device may further include a catheter shaft having opposed ends connected to a tubular member that forms an inflatable medical balloon. The outer diameter of the tubular member may be substantially in the same plane as the outer diameter of the opposed ends of the catheter shaft in the non-inflated state (in other words, it may be aligned or positioned). A guide wire tube may be provided within the catheter shaft and the tubular member that forms the inflatable medical balloon, and the guide wire tube may be connected to the distal tip of the catheter.

[0011] The hub at the proximal end of the catheter shaft may include a first port for supplying inflation fluid to the catheter shaft to expand the tubular member. The hub may further include a second port adapted to receive a guide wire passing through the catheter shaft.

[0012] According to a further embodiment, the medical device includes a catheter shaft including opposed ends connected to a tubular member. The tubular member is formed from a compliant material having one or more fibers therein. Thus, as a result of the compliance of the compliant material, the tubular member forms an inflatable medical balloon of variable diameter when the catheter shaft is pressurized.

[0013] In one embodiment, the compliant material includes a super-compliant material. For example, the super-compliant material may be selected from the group including silicone, polyurethane, hydrogel, or any polymer having an elongation greater than 30% and a Young's modulus less than 100 MPa.

[0014] The one or more fibers may include one or more braided fibers. The one or more fibers may include intersections of the one or more fibers having a first smaller angle in a first smaller inflated state of the medical balloon and a second larger angle in a second larger inflated state of the medical balloon.

[0015] The outer diameter of the tubular member can be substantially in the same plane as the outer diameter of the opposing end of the catheter shaft in a non-expanded state. A guide wire tube can be provided within the catheter shaft and the tubular member forming the inflatable medical balloon, and the guide wire tube can be connected to the distal tip of the catheter shaft.

[0016] The hub can include a first port for supplying inflation fluid to the catheter shaft to expand the tubular member, and can be provided at the proximal end of the catheter shaft. The hub can further include a second port adapted to receive a guide wire passing through the catheter shaft.

[0017] Furthermore, a further aspect of the present disclosure relates to a medical device comprising a catheter shaft connected to an inflatable medical balloon. The catheter shaft includes an outer surface that is coplanar with the outer surface of the inflatable medical balloon in a non-expanded state.

[0018] In one embodiment, the medical balloon comprises a tubular member formed from a compliant material having one or more fibers therein. The compliant material can include a super-compliant material such as silicone, polyurethane, hydrogel, or any polymer selected from the group including those having an elongation greater than 30% and a Young's modulus of less than 100 MPa.

[0019] The one or more fibers can include one or more braided fibers. The one or more fibers can include intersections of the one or more fibers having a first smaller angle in a first smaller inflated state of the medical balloon and a second larger angle in a second larger inflated state of the medical balloon.

[0020] The medical balloon can be attached to the opposing ends of the catheter shaft. A guide wire tube can be provided within the catheter shaft and the inflatable medical balloon, and the guide wire tube can be connected to the distal tip of the catheter shaft.

[0021] The hub may include a first port for supplying inflation fluid to a catheter to expand a medical balloon and may be provided at the proximal end of the catheter shaft. The hub may further include a second port adapted to receive a guide wire passing through the catheter shaft.

[0022] The above and further advantages of the present disclosure may be better understood by reference to the following description in conjunction with the accompanying drawings.

Brief Description of the Drawings

[0023]

Figure 1

Figure 1A

Figure 2

Figure 3

Figure 4

Figure 5

Best Mode for Carrying Out the Invention

[0024] Dimensions of some elements may be emphasized for clarity compared to other elements, or several physical components may be included in one functional block or element. Further, reference numerals may sometimes be repeated in the drawings to indicate corresponding or similar elements. Further, a portion of a unit depicted in the drawings may be combined into a single function.

[0025] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The disclosed embodiments may be practiced without these specific details. In other instances, well-known methods, procedures, components, or structures may not be described in detail so as not to obscure the present invention.

[0026] The principles and operations of the apparatus and methods of the present disclosure may be better understood with reference to the drawings and the accompanying description. The present invention is not limited in its application to the structural details and arrangements of components described in the following description or illustrated in the drawings. The present invention is capable of other embodiments or of being practiced or carried out in various ways. Also, the terminology and phraseology used herein are for the purpose of description and should not be regarded as limiting.

[0027] Certain features of the present invention that are described in the context of separate embodiments for clarity may also be provided in combination in a single embodiment. Conversely, various features of the present invention that are described in the context of a single embodiment for brevity may also be provided separately or in any suitable sub-combination.

[0028] Referring to FIG. 1, a catheter 10 is shown that includes an inflatable medical balloon 12. The medical balloon 12 includes a compliant material that includes one or more embedded fibers 14 encapsulated within the compliant material. The compliant material may be a super-compliant material. For example, a super-compliant material may be defined as any polymer having an extensibility greater than 30% and a Young's modulus of less than 100 MPa. Examples of such materials include silicone, polyurethane, hydrogel, or combinations thereof. Such materials, in combination with a high degree of compliance, puncture resistance, thin walls, and the use of embedded fibers, enable a high burst pressure to be achieved.

[0029] One or more fibers 14 may be provided to form intersections of the one or more fibers. In one example, this may be achieved by providing the one or more fibers in a braided pattern, the braided pattern may include a plurality of intertwined helical fibers, and the helical fibers thus form intersections of a plurality of such fibers, with each of the intersections of the fibers exhibiting an intersection angle or braiding angle. The braiding may be along the length of the tubular member at a constant small winding angle, or at a variable winding angle. One or more braided or intersecting fibers may have an axial intersection angle that can change as a result of the radial expansion of the balloon 12, as further outlined in the following description.

[0030] One or more fibers 14 may be formed from a variety of inelastic materials including, but not limited to, Kevlar®, Vectran®, Spectra, Dacron®, Dyneema®, Turlon (PBT), Zylon® (PBO), polyimide (PIM), and other ultra-high molecular weight polyurethanes, aramids, etc. In one embodiment, the fiber 14 may be an aramid fiber, preferably a multifilament. In another embodiment, the fiber 14 may be a para-aramid fiber, preferably a multifilament. In one example, the fiber 14 may be a Technora® brand para-phenylene / 3,4-oxydiphenylene / terephthalamide copolymer, preferably a multifilament.

[0031] Catheter 10 including balloon 12 can be constructed by attaching a tubular member including a compliant material and embedded fibers to opposite ends 16a, 16b of catheter shaft 16 which has dimensional stability and thus is non-compliant (i.e., does not expand radially when fluid pressure is applied). The attachment can be achieved by coupling or fusing the ends of the tubular member to the corresponding ends 16a, 16b of shaft 16. As can be understood from FIG. 1, the outer diameter of the tubular member can be attached such that in a nominal state (i.e., a state where no inflation pressure is applied), it is substantially in the same plane as the outer diameter of one or both of the adjacent shaft ends 16a, 16b. Thus, catheter 10 has a smooth, continuous outer surface which is therefore well adapted to pass through blood vessels and particularly tortuous anatomical structures. This arrangement also eliminates the need for kinking, coiling or folding of the medical balloon prior to introduction into the blood vessel, thereby saving time and cost. The same benefit can also be obtained by attaching the ends of the tubular member within the lumen of shaft ends 16a, 16b or by attaching the tubular member to the outer surface of the shaft ends in situations where such a smooth shape is not required.

[0032] Also, as shown in FIG. 1A, catheter 10 can include an internal tube 18 within shaft 16 that can form a lumen for guide wire 20. This internal tube 18 can be connected to proximal hub 22 at the proximal end of catheter 10 and sealed at its distal end to distal tip 24, thereby fixing the length of shaft 16 against longitudinal expansion. Hub 22 can include a first inflation port 26 for supplying inflation fluid from an inflator (not shown) to an annular region A between the outer surface of internal tube 18 and the inside or inner surface of balloon 12, and a second port 28 for receiving guide wire 20 that can pass through distal tip 24.

[0033] Accordingly, by applying an inflation pressure to the shaft 16, particularly to the annular portion A, the medical balloon 12 can be radially expanded via the inflation port 26 to engage a lesion in a blood vessel. In other words, the medical balloon 12, and in addition the shaft 16, form a continuous inner compartment that can receive inflation fluid, but only the tubular member can expand, as a result of compliance, to form the balloon 12. The expansion can change, as shown in FIG. 2, to a first inflated state 12' having a first diameter with a first magnitude of fluid pressure applied, and as shown in FIG. 3, to a second inflated state 12'' having a second larger diameter with a second increased magnitude of fluid pressure applied, and so on. As can be appreciated, this can result in a change in the relative angle of the intersecting fibers 14 from a first smaller angle α with respect to the axial or longitudinal axis, as shown in FIG. 4 (fiber 14'), to a second larger angle β with respect to the axial or longitudinal axis, as shown in FIG. 5 (fiber 14'').

[0034] In connection with the use of a compliant material, this enables the variable diameter of the balloon 12 to be achieved by a corresponding increase or decrease in the fluid pressure applied to the shaft 16, and the shaft 16 is further dimensionally stable and thus does not follow the changes as a result of the applied fluid pressure. As a result, the medical balloon 12 according to the present disclosure is useful for treating blood vessels of various diameters, in contrast to a non-compliant balloon having a generally fixed nominal inflation diameter. Further, since the fibers 14 resist the expansion of the compliant material in which they are embedded, they allow radial expansion with increasing pressure only in a controlled manner.

[0035] To form a compliant tubular member, one or more fibers 14 can be placed into a matrix material during a coextrusion process or by simultaneous molding. One or more fibers 14 can also be applied overlying the outer surface of the compliant tubular member, and the compliant tubular member can then be coated with additional compliant material to encapsulate the fibers therein. Although a braided arrangement is shown, the fibers 14 can extend longitudinally, helically, or both, at any desired angle, and can be provided in one or more layers.

[0036] In summary, the present disclosure can be considered to relate to the following items. 1. A medical device comprising an inflatable medical balloon having a variable diameter and comprising a super-compliant material in which one or more fibers are embedded. 2. The device of item 1, wherein the super-compliant material is selected from the group consisting of silicone, polyurethane, hydrogel, or any polymer having an elongation greater than 30% and a Young's modulus of less than 100 MPa. 3. The device of item 1 or item 2, wherein the one or more fibers comprise one or more braided fibers. 4. The device of any one of items 1-3, comprising intersections of the one or more fibers, wherein the one or more fibers have a first, smaller angle in a first, smaller inflated state of the medical balloon and a second, larger angle in a second, larger inflated state of the medical balloon. 5. The device of any one of items 1-4, further comprising a catheter shaft having opposed ends connected to a tubular member forming the inflatable medical balloon. 6. The device of item 5, wherein the outer diameter of the tubular member is in substantially the same plane as the outer diameter of the opposed ends of the catheter shaft. 7. The device of item 5 or item 6, further comprising a catheter shaft and a guide wire tube within the tubular member forming the inflatable medical balloon, the guide wire tube being connected to the distal tip of the catheter. 8. The apparatus according to any one of items 5 - 7, further comprising a hub at the proximal end of the catheter shaft, the hub including a first port for supplying inflation fluid to the catheter shaft to expand the tubular member. 9. The apparatus according to item 8, wherein the hub further includes a second port adapted to receive a guide wire for passing through the catheter shaft. 10. A medical device comprising a catheter shaft having opposed ends connected to a tubular member, the tubular member being formed from a compliant material having one or more fibers therein, and as a result of the compliance of the compliant material, the tubular member is configured to form an inflatable medical balloon having a variable diameter when the catheter shaft is pressurized. 11. The apparatus according to item 10, wherein the compliant material includes a super-compliant material. 12. The apparatus according to item 11, wherein the super-compliant material is selected from the group consisting of silicone, polyurethane, hydrogel, or any polymer having an elongation greater than 30% and a Young's modulus less than 100 MPa. 13. The apparatus according to any one of items 10 - 12, wherein the one or more fibers include one or more braided fibers. 14. The apparatus according to any one of items 10 - 13, including intersections of one or more fibers, wherein the one or more fibers have a first smaller angle in a first smaller inflated state of the medical balloon and a second larger angle in a second larger inflated state of the medical balloon. 15. The apparatus according to any one of items 10 - 14, wherein the outer diameter of the tubular member is in substantially the same plane as the outer diameter of the opposed ends of the catheter shaft. 16. The apparatus according to any one of items 10 - 15, further comprising a catheter shaft and a guide wire tube within the tubular member forming the inflatable medical balloon, the guide wire tube being connected to the distal tip of the catheter shaft. 17. The apparatus according to any one of items 10 - 16, further comprising a hub at the proximal end of the catheter shaft, the hub including a first port for supplying inflation fluid to the catheter shaft to expand the tubular member. 18. The apparatus of item 17, wherein the hub further includes a second port adapted to receive a guide wire for passing through the catheter shaft. 19. A medical device comprising a catheter shaft connected to an inflatable medical balloon, the catheter shaft having an outer surface that lies in the same plane as the outer surface of the inflatable medical balloon. Medical device. 20. The apparatus of item 19, wherein the medical balloon comprises a tubular member formed from a compliant material having one or more fibers therein. 21. The apparatus of item 20, wherein the compliant material includes a super-compliant material. 22. The apparatus of item 21, wherein the super-compliant material is selected from the group consisting of silicone, polyurethane, hydrogel, or any polymer having an elongation greater than 30% and a Young's modulus of less than 100 MPa. 23. The apparatus of any one of items 20 - 22, wherein the one or more fibers include one or more braided fibers. 24. The apparatus of any one of items 20 - 23, wherein the one or more fibers include intersections of the one or more fibers having a first smaller angle in a first smaller inflated state of the medical balloon and a second larger angle in a second larger inflated state of the medical balloon. 25. The apparatus of any one of items 19 - 24, wherein the medical balloon is attached to opposite ends of the catheter shaft. 26. The apparatus of any one of items 19 - 25, further comprising a guide wire tube within the catheter shaft and the inflatable medical balloon, the guide wire tube being connected to the distal tip of the catheter shaft. 27. The apparatus of any one of items 19 - 26, further comprising a hub at the proximal end of the catheter shaft, the hub including a first port for supplying inflation fluid to the catheter shaft to expand the medical balloon. 28. The apparatus of item 27, wherein the hub further includes a second port adapted to receive a guide wire for passing through the catheter shaft.

[0037] As used herein, the following terms have the following meanings: As used herein, the terms "a", "an", and "the" refer to both singular and plural referents unless the context clearly states otherwise. By way of example, "a component" refers to one or more than one component.

[0038] As used herein, "about", "substantially", or "approximately", when referring to a measurable value such as a parameter, amount, time period, etc., encompasses variations of + / - 20% or less, including variations of + / - 10% or less, + / - 5% or less, + / - 1% or less, and + / - 0.1% or less from a particular value and such variations are intended to be suitable for implementation in the disclosed invention. However, it is to be understood that the value to which such modifiers refer may itself be specifically disclosed.

[0039] As used herein, "comprise", "comprising", "comprises", and "comprised of" are synonymous with "include", "including", "includes", or "contain", "containing", "contains", and are inclusive or open-ended terms that do not exclude the presence of additional, unrecited components, features, elements, members, steps, known or disclosed in the art.

[0040] Although the invention has been described in conjunction with specific embodiments, many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, the invention encompasses all such alternatives, modifications, and variations that fall within the spirit and scope of the appended claims. All publications, patents, and patent applications mentioned in this specification are hereby incorporated by reference in their entirety to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference herein. Additionally, or alternatively, any identification of a reference in this application should not be construed as an admission that such reference is available as prior art to this disclosure.

Claims

**Claim 1** A medical device comprising a medical balloon having a variable diameter and comprising a super-compliant material in which one or more fibers are embedded. **Claim 2** The device of claim 1, wherein the super-compliant material is selected from the group consisting of silicone, polyurethane, hydrogel, or any polymer having an elongation greater than 30% and a Young's modulus of less than 100 MPa. **Claim 3** The device of claim 1, wherein the one or more fibers form a braided pattern. **Claim 4** The device of claim 1, comprising intersections of one or more fibers that have a first smaller angle in a first smaller inflated state of the medical balloon and a second larger angle in a second larger inflated state of the medical balloon. **Claim 5** The device of claim 1, further comprising a catheter shaft having opposed ends connected to a tubular member forming the inflatable medical balloon. **Claim 6** The device of claim 5, wherein an outer diameter of the tubular member is in substantially the same plane as an outer diameter of the opposed ends of the catheter shaft in a non-inflated state. **Claim 7** The device of claim 5, further comprising the catheter shaft and a guide wire tube within the tubular member forming the inflatable medical balloon, the guide wire tube being connected to a distal tip of the catheter. **Claim 8** The device of claim 5, further comprising a hub at a proximal end of the catheter shaft, the hub including a first port for supplying inflation fluid to the catheter shaft to expand the tubular member. **Claim 9** The device of claim 8, wherein the hub further includes a second port adapted to receive a guide wire passing through the catheter shaft. **Claim 10** A medical device comprising a catheter shaft having opposed ends connected to a tubular member, the tubular member being formed from a compliant material having one or more fibers therein, and configured such that as a result of the compliance of the compliant material, the tubular member forms an inflatable medical balloon having a variable diameter when the catheter shaft is pressurized. **Claim 11** The device of claim 10, wherein the compliant material includes a super-compliant material.

12. The apparatus of claim 11, wherein the super-compliant material is selected from the group consisting of silicone, polyurethane, hydrogel, or any polymer having an elongation greater than 30% and a Young's modulus of less than 100 MPa.

13. The apparatus of claim 10, wherein the one or more fibers include one or more braided fibers.

14. The apparatus of claim 10, wherein the one or more fibers include intersections of one or more fibers having a first, smaller angle in a first, smaller inflated state of the medical balloon and a second, larger angle in a second, larger inflated state of the medical balloon.

15. The apparatus of claim 10, wherein an outer diameter of the tubular member is substantially in the same plane as an outer diameter of the opposing end of the catheter shaft in a non-inflated state.

16. The apparatus of claim 10, further comprising a guide wire tube within the tubular member forming the catheter shaft and the inflatable medical balloon, the guide wire tube being connected to a distal tip of the catheter shaft.

17. The apparatus of claim 10, further comprising a hub at a proximal end of the catheter shaft, the hub including a first port for supplying inflation fluid to the catheter shaft to expand the tubular member.

18. The apparatus of claim 17, wherein the hub further includes a second port adapted to receive a guide wire passing through the catheter shaft.

19. A medical device comprising a catheter shaft connected to an inflatable medical balloon, the catheter shaft having an outer surface that is coplanar with an outer surface of the inflatable medical balloon in a non-inflated state.

20. The apparatus of claim 19, wherein the medical balloon comprises a tubular member formed from a compliant material having one or more fibers therein.

21. The apparatus of claim 20, wherein the compliant material includes a super-compliant material.

22. The apparatus of claim 21, wherein the super-compliant material is selected from the group consisting of silicone, polyurethane, hydrogel, or any polymer having an elongation greater than 30% and a Young's modulus of less than 100 MPa.

23. The apparatus of claim 20, wherein the one or more fibers form a knitted pattern.

24. The apparatus of claim 20, comprising an intersection of one or more fibers, wherein the one or more fibers have a first smaller angle in a first smaller inflated state of the medical balloon and a second larger angle in a second larger inflated state of the medical balloon.

25. The apparatus of claim 19, wherein the medical balloon is attached to opposite ends of the catheter shaft.

26. The apparatus of claim 19, further comprising a guide wire tube within the catheter shaft and the inflatable medical balloon, wherein the guide wire tube is connected to a distal tip of the catheter shaft.

27. The apparatus of claim 19, further comprising a hub at a proximal end of the catheter shaft, the hub including a first port for supplying inflation fluid to the catheter shaft to expand the medical balloon.

28. The apparatus of claim 27, wherein the hub further includes a second port adapted to receive a guide wire passing through the catheter shaft.

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