Cutting balloon catheter with improved balloon configuration

An angioplasty balloon catheter and method of making and using the same. The balloon catheter may include a catheter shaft and a balloon coupled to the shaft. The balloon may include one or more cutting edges or member and may include one or more wings. The wings may include an undulating surface.

FIELD OF THE INVENTION

The present invention pertains to angioplasty and angioplasty balloon catheters. More particularly, the present invention pertains to angioplasty balloon catheters that include one or more cutting edges and angioplasty balloons with improved folding and re-folding properties.

BACKGROUND

Heart and vascular disease are major problems in the United States and throughout the world. Conditions such as atherosclerosis result in blood vessels becoming blocked or narrowed. This blockage can result in lack of oxygenation of the heart, which has significant consequences since the heart muscle must be well oxygenated in order to maintain its blood pumping action.

Occluded, stenotic, or narrowed blood vessels may be treated with a number of relatively non-invasive medical procedures including percutaneous transluminal angioplasty (PTA), percutaneous transluminal coronary angioplasty (PTCA), and atherectomy. Angioplasty techniques typically involve the use of a balloon catheter. The balloon catheter is advanced over a guidewire so that the balloon is positioned adjacent a stenotic lesion. The balloon is then inflated, and the restriction of the vessel is opened.

One of the major obstacles in treating coronary artery disease and/or treating blocked blood vessels is re-stenosis. Evidence has shown that cutting the stenosis, for example with an angioplasty balloon equipped with a cutting blade, during treatment can reduce incidence of re-stenosis. Additionally, cutting the stenosis may reduce trauma at the treatment site and/or may reduce the trauma to adjacent healthy tissue. Cutting blades may also be beneficial additions to angioplasty procedures when the targeted occlusion is hardened or calcified. It is believed typical angioplasty balloons, alone, may not be able to expand certain of these hardened lesions. Thus, angioplasty balloons equipped with cutting edges have been developed to attempt to enhance angioplasty treatments. There is an ongoing need for improved angioplasty devices, including cutting angioplasty balloons, and improved methods of treating intravascular stenoses and occlusions.

Another potential obstacle that may accompany treatments that include expansion of a stenosis with an angioplasty balloon is the removal of the balloon from the vessel. This is because when the balloon is deflated, it may tend to maintain a relatively large profile. Moreover, if the balloon includes a cutting edge, the potential exists for the cutting edge to be disposed at a large profile region of the balloon. This could subject healthy tissue to unnecessary contact with the cutting edge and resultant abrasion or cutting during the balloon removal procedure. Accordingly, there is an ongoing need for improved angioplasty devices, including cutting angioplasty balloons, with improved re-folding abilities.

BRIEF SUMMARY

The present invention relates to angioplasty balloon catheters. In at least some embodiments, an example balloon catheter may include a catheter shaft having a balloon coupled thereto. The balloon may include one or more cutting members or blades. Additionally, the balloon may include a number of wings when the balloon is deflated or partially deflated. The wings may improve the folding and refolding abilities of the balloon. The wings may also include one or more undulating surfaces. These and other features are described in more detail below.

DETAILED DESCRIPTION

The following description should be read with reference to the drawings wherein like reference numerals indicate like elements throughout the several views. The detailed description and drawings illustrate example embodiments of the claimed invention.

FIG. 1is a partial cross-sectional side view of a distal portion of a catheter10. Catheter10includes a catheter shaft12and an expandable balloon14coupled to shaft12. Balloon14may include one or more cutting members16that may be used, for example, to sever tissue adjacent a stenosis and/or otherwise compliment the expansion of a stenotic lesion. In general, balloon catheter10may include similarities in structure and use to other balloon catheters. For example, catheter10can be advanced through the vasculature to a position adjacent a target area (e.g., an intravascular lesion) and balloon14may be expanded to expand the lesion. Uses for catheter10may include cardiac interventions as well as peripheral interventions including esophageal, urethral, and other peripheral interventions.

In at least some embodiments, balloon14may be configured to have desirable folding and re-folding abilities. For example, balloon14may be adapted to have “wings” (best seen inFIGS. 2 and 3) that are pre-formed during manufacturing and that can be seen when balloon14is deflated. The wings allow balloon14to re-fold into a relatively low-profile configuration so that balloon14can be more easily removed from the blood vessel. Additionally, the wings may be able to roll over or otherwise fold over and cover cutting members16so as to shield the vessel from cutting members16during the transportation of balloon14. Some of the other features and benefits of catheter10are described in more detail below.

Cutting members16may be a blade or other structure configured for cutting into tissue such as a lesion. For example, cutting members16may include a metallic cutting blade that is similar to a knife. However, the material composition, shape, and appearance of cutting members16may vary. Cutting members16may be attached to balloon14in any suitable way. For example, cutting members16may be secured by adhesives. Alternatively, cutting members16may be connected to balloon14using welding (e.g., resistance or laser welding), soldering, brazing, thermal bonding, or the like, combinations thereof, or any suitable method.

In some embodiments, four cutting members16are disposed around balloon14. However, the exact number of cutting members16and the exact position of cutting members16on balloon14may vary. For example, balloon14may include one to six cutting members16or more and the cutting members16may be regularly distributed, irregularly distributed, randomly distributed, or otherwise disposed in any manner.

Balloon14may be made from typical angioplasty balloon materials including polymers such as polyethylene terephthalate (PET), polyetherimid (PEI), polyethylene (PE), etc. Some other examples of suitable polymers may include polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene (POM), polybutylene terephthalate (PBT), polyether block ester, polyurethane, polypropylene (PP), polyvinylchloride (PVC), polyether-ester (for example, a polyether-ester elastomer such as ARNITEL® available from DSM Engineering Plastics), polyester (for example, a polyester elastomer such as HYTREL® available from DuPont), polyamide (for example, DURETHAN® available from Bayer or CRISTAMID® available from Elf Atochem), elastomeric polyamides, block polyamide/ethers, polyether block amide (PEBA, for example, available under the trade name PEBAX®), silicones, Marlex high-density polyethylene, Marlex low-density polyethylene, linear low density polyethylene (for example, REXELL®), polyetheretherketone (PEEK), polyimide (PI), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polysulfone, nylon, perfluoro(propyl vinyl ether) (PFA), other suitable materials, or mixtures, combinations, copolymers thereof, polymer/metal composites, and the like. Alternatively, balloon14may be made from other materials including those which may be somewhat stronger or stiffer in order to provide structural support for cutting members16. Accordingly, the stiffer materials may be disposed adjacent cutting members16. Some examples of these stiffer materials include polymers blended with liquid crystal polymer (LCP) as well as the materials listed above. For example, the mixture can contain up to about 5% LCP.

Catheter shaft12may include an inner tubular member18and an outer tubular member20. Tubular members18/20may be manufactured from a number of different materials. For example, tubular members18/20may be made of metals, metal alloys, polymers, metal-polymer composites, or any other suitable materials. Some examples of suitable metals and metal alloys include stainless steel, such as 304V, 304L, and 316L stainless steel; nickel-titanium alloy such as linear-elastic or super-elastic nitinol, nickel-chromium alloy, nickel-chromium-iron alloy, cobalt alloy, tungsten or tungsten alloys, MP35-N (having a composition of about 35% Ni, 35% Co, 20% Cr, 9.75% Mo, a maximum 1% Fe, a maximum 1% Ti, a maximum 0.25% C, a maximum 0.15% Mn, and a maximum 0.15% Si), hastelloy, monel 400, inconel 825, or the like; or other suitable material. Some examples of suitable polymers include those described above in relation to balloon14.

Tubular members18/20may be arranged in any appropriate way. For example, in some embodiments inner tubular member18can be disposed coaxially within outer tubular member20. According to these embodiments, inner and outer tubular members18/20may or may not be secured to one another along the general longitudinal axis of catheter shaft12. Alternatively, inner tubular member18may follow the inner wall or otherwise be disposed adjacent the inner wall of outer tubular member20. Again, inner and outer tubular members18/20may or may not be secured to one another. For example in one preferred embodiment, inner and outer tubular members20may be bonded, welded (including tack welding or any other welding technique), or otherwise secured at a bond point22. In some embodiments, bond point22may be generally disposed near the distal end of catheter shaft12. However, one or more bond points22may be disposed at any position along shaft12. Bond22may desirably impact, for example, the stability and the ability of tubular members18/20to maintain their position relative to one another. In still other embodiments, inner and outer tubular member18/20may be substantially parallel to one another so that they are non-overlapping. In these embodiments, shaft12may include an outer sheath that is disposed over tubular members18/20.

Inner tubular member18may include an inner lumen24. In at least some embodiments, inner lumen24is a guidewire lumen. Accordingly, catheter10can be advanced over a guidewire to the desired location. The guidewire lumen may extend along essentially the entire length of catheter shaft12so that catheter10resembles traditional “over-the-wire” catheters. Alternatively, the guidewire lumen may extend along only a portion of shaft12so that catheter10resembles “single-operator-exchange” or “rapid-exchange” catheters.

In some embodiments, one or more marker members26may be coupled to inner tubular member18, or at essentially any other suitable position on catheter10. Marker members26may include, be made from, be doped with, or otherwise include a radiopaque material. Radiopaque materials are understood to be materials capable of producing a relatively bright image on a fluoroscopy screen or another imaging technique during a medical procedure. This relatively bright image aids the user of catheter10in determining its location. Some examples of radiopaque materials can include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloy, plastic material loaded with a radiopaque filler, and the like.

Shaft12may also include an inflation lumen28that may be used, for example, to transport inflation media to and from balloon14. The location and position of inflation lumen28may vary, depending on the configuration of tubular members18/20. For example, when outer tubular member20is disposed over inner tubular member18, inflation lumen28may be defined within the annular space between tubular members18/20. Moreover, depending on the position of inner tubular member18within outer tubular member20, the shape of lumen28may vary. For example, if inner tubular member18is attached to or disposed adjacent to the inside surface of outer tubular member20, then inflation lumen28may be generally half-moon in shape; whereas if inner tubular member18is generally coaxial with outer tubular member20, then inflation lumen28may be generally ring-shaped or annular in shape. It can be appreciated that if outer tubular member20is disposed alongside inner tubular member18, then lumen28may be the lumen of outer tubular member20or it may be the space defined between the outer surface of tubular members18/20and the outer sheath disposed thereover.

Balloon14may be coupled to catheter shaft12in any of a number of suitable ways. For example, balloon14may be adhesively or thermally bonded to shaft12. In some embodiments, a proximal portion32of balloon14may be bonded to shaft12, for example, at outer tubular member20, and a distal portion32may be bonded to shaft12, for example, at inner tubular member18. The exact bonding positions, however, may vary.

A folding spring36may be coupled to balloon14, for example, adjacent proximal portion32. A description of a suitable folding spring, essentially the same in form and function as folding spring36, can be found in U.S. Pat. No. 6,425,882 the disclosure, of which is incorporated herein by reference. Folding spring36may generally include a base or band38and one or more fingers40extending distally from base38. Fingers40may be adapted to shift between a first collapsed configuration and a second expanded configuration. In some embodiments, fingers40are biased to be in the first configuration. Accordingly, when balloon14is collapsed, fingers40assume the first configuration and when balloon14is expanded, the outward force of balloon14on fingers40can overcome the bias so that fingers40assume the second configuration. The ability of folding spring36to shift between configurations may assist balloon refolding or otherwise improve the refolding ability of balloon14. For example, biasing folding spring36in the first configuration may allow fingers40to exert force on balloon14(when not inflated) so that balloon14may be at least partially collapsed.

Balloon14may be configured so that it includes one or more wings42as shown inFIG. 2. In general, wings42are visible and can be seen when balloon14is deflated. The appearance of wings42includes a plurality of alternating inward and outward radial deflection in balloon14. Wings42may allow balloon14to have more predictable and consistent re-folding characteristics. For example, wings42may help balloon14fold inward at a plurality of positions so that the overall profile of balloon14in a deflated state can be reduced. In some embodiments, balloon14includes four wings42. However, the number of wings42can vary and can be any suitable number such as three, five, six, or more. The distribution of wings42may also vary. For example, wings42may be evenly, regularly, irregularly, randomly, or otherwise dispersed in any manner about balloon14.

In at least some embodiments, wings42may be dispersed so that wings42and cutting members16alternate. Additionally, it may be desirable to configure wings42so that cutting members16are positioned at the inward-most positions of wings42. This arrangement allows cutting members16to be positioned more closely to shaft12when balloon14is deflated. Accordingly, cutting members16can be moved away from the vessel walls where they might otherwise result in contact and, possibly, damage to healthy tissue during movement of catheter10within a body lumen. Additionally, alternating wings42and cutting members12as well as positioning cutting members16relatively close to shaft12may allow wings42to fold over and cover cutting members16when balloon14is deflated. Again, this feature may reduce the exposure of cutting members16to the blood vessel.

Wings42may also include one or more undulations or an undulating surface as indicated inFIG. 2by reference number44. In general, undulations44may resemble waves or peaks and valleys formed in wings42. In some embodiments, the “peaks” of undulations44line up along the longitudinal axis of balloon14. However, this need not be the case. Additionally, the number, arrangements, and position of undulations44may vary in different example embodiments as well as among the different wings42of a particular embodiment. For example, some example wings42may include relatively few undulations44while other example wings42may include several. Moreover, some wing42embodiments may include undulations44that have opposing “peaks” similar to what is shown inFIG. 3, while other wings42may include nesting or aligned peaks or any other suitable configuration.

Undulations44may be desirable for a number of reasons. For example, undulations44may increase the surface area of wings42so that wings42have a shorter radial length than they would otherwise have without undulations44. Accordingly, when balloon14is in the deflated configuration, undulations44may allow wings42to be even closer to shaft12and, thus, decrease the overall profile of deflated balloon14.

Also shown inFIG. 2is that folding spring36may be configured so that fingers40can extend between adjacent wings42. Because folding spring36may be biased to be in the collapsed configuration (as described above), fingers40may help balloon14collapse and expose wings42by exerting force on balloon14between wings42. The bias of folding spring36may be overcome by infusing inflation media into balloon14and inflating balloon14.

FIG. 3is a cross-sectional view taken along line3-3inFIG. 2that shows undulations44disposed in wings42. Here it can be seen how undulations44may define waves with longitudinally-aligned peaks and valleys. Of course, other embodiments may include waves with differing configurations such as non-aligned waves. It can also be seen how the peaks of undulations44may be opposed. Alternative embodiments, however, include undulations44that are nested or aligned, randomly distributed, or include various combinations of configurations. Also shown inFIG. 3is a portion of shaft12, for example inner tubular member18, extending at least partially through balloon14.

When balloon14is inflated, wings42may become expanded and, thus, not visible as illustrated inFIG. 4. This alternative cross-sectional view shows how inflating balloon14can essentially expand wings42and move cutting members16toward the outer periphery of balloon14for the desired cutting action. It can be appreciated that upon deflation, balloon14can assume the winged configuration shown inFIG. 3.

FIG. 5is a schematic view of a wing-forming apparatus46that may be used to form wings42and/or undulations44. Wing-forming apparatus46may include a plurality of jaws or jaw members48that each include an undulating surface50and a blade opening52. Jaw members48may be generally metallic and can be used to “iron” or otherwise define wings42and undulations44in wings42. The ironing process may include aligning balloon14and jaw members48so that cutting members16are disposed adjacent blade openings52. In some embodiments, jaw members48may be movably mounted to a frame structure so that jaw members48can be moved inwardly toward the center of balloon14. The result may be balloon14bending inward similar to what is shown inFIG. 6.

In at least some embodiments, the use of apparatus46may include subjecting balloon14to heat and/or pressure in order to form and define wings42and undulations44in balloon14. Generally, wings42can be defined in balloon14adjacent spaces between a pair of jaw members48and undulations44may be defined adjacent undulating surfaces50of jaw members48. The source of the heat and pressure may vary. For example, apparatus46may be disposed within an oven or other suitable heating device so that the balloon can be heated during the ironing procedure. Additionally, the oven may also include pressure controls so that the pressure within the oven may be varied. Alternatively, heat and pressure may be provided by other sources such as external electrodes or connectors, electrical or other types of energy, or in any other suitable manner. Generally, the use of apparatus46results in the alteration of the geometry of balloon14so that a generally repeatable deflation shape is formed in the balloon material so that wings42are formed and visible when balloon14is deflated. It is believed that the disclosed balloon geometry, that may include a plurality of wings42having undulations44, helps render the balloon more foldable, more re-foldable, and more collapsible.

Apparatus46may alternatively be configured similarly to what is shown inFIG. 6so that balloon14may be aligned with jaw members48(e.g., with cutting members16aligned with blade openings52) and pushed, pulled, or otherwise advanced into contact with and/or through apparatus46. This arrangement allows wings42to be formed and undulations44to be defined by undulating surfaces50.

FIG. 7is an enlarged view of jaw member48that illustrates some example configurations and dimensions. First, it can be seen that jaw member48can have a pair of undulating surfaces50/50′. In some embodiments, surfaces50/50′ may be substantially symmetrical. Alternatively, surfaces50/50′ may be somewhat offset from one another. For example, surface50may have a relatively short top undulation portion54that may be about 0.002 to about 0.012 inches long, and surface50′ may have a somewhat longer top undulation portion54′ that may be about 0.012 to about 0.028 inches long. Staggering or offsetting top portions54/54′ may be desirable, for example, by allowing for adjacent jaw members48to be disposed more closely to one another by positioning a short top portion (e.g., similar to portion54) adjacent a somewhat longer top portion (e.g., similar to portion54′).

FIG. 7also illustrates that undulating surfaces50/50′ may be sized to define undulations44having an undulation height, HU, and an undulation length, LU. The precise dimension for HUand LUmay vary. For example, HUand LUmay each be about 0.010 to about 0.030 inches or so. In some embodiments, HUand LUmay be the same size as one another, while in other embodiments they may differ. Similarly, opposing undulating surfaces50/50′ may have undulations with the same or different HUand LU. Undulating surfaces50/50′ may also rise adjacent an individual undulation at an angle θ that may be about 5 to about 15 degree or so. Angle θ may be the same or different among individual undulations of a particular surface (e.g., surface50or50′) and, similarly, may vary between different undulating surfaces50/50′.

It should be understood that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of steps without exceeding the scope of the invention. The invention's scope is, of course, defined in the language in which the appended claims are expressed.