US20060184191A1 - Cutting balloon catheter having increased flexibility regions - Google Patents

Abstract

A cutting balloon catheter and method of using the same. The cutting balloon catheter may include a catheter shaft having a balloon coupled thereto. One or more cutting members or blades may be coupled to the balloon. The balloon may include one or more discrete points or areas of flexibility to enhance flexibility of the cutting balloon catheter. A break in the one or more cutting members may be aligned with the one or more discrete points of flexibility in the balloon.

Description

TECHNICAL FIELD
• 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 coupled to an angioplasty balloon having increased flexibility.
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 a lack of oxygenation to 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 may be advanced through a vasculature over a guidewire so that the balloon is positioned at a target location. The balloon may then be inflated in a manner such that the restriction in 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 edge, during treatment can reduce incidence of re-stenosis. Additionally, cutting the stenosis may reduce trauma at the treatment site and/or 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 sufficiently expand at least a portion of these hardened lesions. Thus, angioplasty balloons equipped with cutting edges have been developed in an 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.
SUMMARY
• The invention generally relates to improved angioplasty devices for treating vascular abnormalities, such as a stenosis. In at least some embodiments, an exemplary angioplasty device may include a catheter shaft having a balloon coupled thereto. One or more cutting members or blades may be coupled to the balloon. The balloon may include one or more discrete points or areas of flexibility to improve the flexibility of the balloon during delivery, deployment, and/or withdrawal of an angioplasty device. Such discrete points or areas of flexibility may include one or more creases, folds, reduced diameter portions, less expandable portions, regions of reduced wall thickness, and the like, formed in a portion of the balloon.
• Accordingly, one exemplary embodiment of the invention is a cutting balloon catheter including a balloon having one or more generally circumferentially extending creases formed in the balloon wall. One or more cutting members may be coupled to the balloon such that breaks in the cutting members, or segments thereof, are aligned with the one or more creases to impart greater flexibility to the balloon portion.
• Another embodiment of the invention includes an atherotomy device for the treatment of coronary artery disease. The atherotomy device includes a plurality of cutting edges or atherotomes coupled to an inflatable balloon. The atherotomes may be segmented to provide flexibility. The balloon may also include at least one circumferential crease to improve the flexibility of the balloon during an atherotomy procedure. The flexibility provided by the at least one circumferential crease and/or the segmented atherotomes allows the cutting balloon to more readily conform to the curvature of a vascular passageway. Balloons not having such flexibility may tend to straighten as they are inflated in a curved vascular pathway, thereby placing uneven pressure on the wall of the vessel and subjecting unnecessary trauma to the vessel.
BRIEF DESCRIPTION OF THE DRAWINGS
• The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, in which:
• FIG. 1 is a partial cross-sectional view of a representative cutting balloon catheter in accordance with an embodiment of the invention;
• FIG. 2 is a partial perspective view of a representative cutting member and balloon having at least one generally circumferentially extending crease in accordance with an embodiment of the invention;
• FIG. 3 is a partial perspective view of another representative cutting member and balloon having at least one generally circumferentially extending crease in accordance with an embodiment of the invention;
• FIG. 4 is a partial perspective view of a representative cutting balloon catheter including a balloon having at least one crease in accordance with an embodiment of the invention;
• FIG. 5 is a partial perspective view of another representative cutting balloon catheter including a balloon having at least one crease in accordance with an embodiment of the invention;
• FIG. 6 is a partial perspective view of another representative cutting balloon catheter including a balloon having at least one crease in accordance with an embodiment of the invention;
• FIG. 7 is a partial cross-sectional view of a representative cutting balloon catheter disposed in a curved vasculature;
• FIG. 8 is a partial perspective view of another representative cutting balloon catheter including a multi-lobed balloon; and
• FIG. 9 is a partial perspective view of another representative cutting balloon catheter including a plurality of expandable balloons.
DETAILED DESCRIPTION
• For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification.
• All numeric values are herein assumed to be modified by the term “about”, whether or not explicitly indicated. Unless indicated otherwise, the term “about” generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (i.e., having the same function or result). In many instances, the term “about” may include numbers that are rounded to the nearest significant figure.
• The recitation of numerical ranges by endpoints includes all numbers within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.
• The following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The detailed description and the drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the invention. The illustrative embodiments depicted are intended only as exemplary. Selected features of any illustrative embodiment may be incorporated into an additional embodiment unless clearly stated to the contrary.
• FIG. 1 is a partial cross-sectional side view of anexemplary catheter10 disposed in ablood vessel12 and positioned adjacent anintravascular lesion14.Catheter10 may include aballoon16 coupled to acatheter shaft18. One or more cutting members orblades20 may be coupled toballoon16. In general,catheter10 may be advanced over aguidewire22, through the vasculature, to a target area.Balloon16 can then be inflated to expandlesion14, and cuttingmembers20 may cutlesion14. The target area may be within any suitable peripheral, cardiac or other vessel lumen location.
• Cuttingmembers20 may vary in number, position, and arrangement aboutballoon16. For example,catheter10 may include one, two, three, four, five, six, or more cuttingmembers20 that are disposed at any position alongballoon16 and in a regular, irregular, or any other suitable pattern. The pattern can include a generally helical orientation of thecutting members20.Catheter10 may include a plurality of cuttingmembers20 placed equidistantly aboutballoon16 extending generally longitudinally. In general, cuttingmembers20 may be configured to provide variable flexibility or otherwise vary the flexibility ofcatheter10. Increasing the flexibility of cuttingmembers20,balloon16, and/orcatheter10 may be desirable, for example, because it may improve the tracking ability and general deliverability ofcatheter10 through the often tortuous anatomy. Additionally, increasing the flexibility may allowcatheter10 to be navigable to a larger number of intravascular locations, including some that may not be readily reachable by other, less flexible, cutting balloon catheters. In general, the enhanced flexibility may be the result of a structural feature of cuttingmembers20, a structural modification to cuttingmembers20, and/or a structural feature of the cuttingballoon16. For example, cuttingmembers20 may include afirst section44a, asecond section44b, and a gap or break46 disposed betweenfirst section44aandsecond section44b.Break46 may be configured to provide a region of flexibility such as a space betweenfirst section44aandsecond section44b. In some embodiments, break46 may be defined by a downward deflection or slot that is formed in the cutting surface of cuttingmember20. Alternatively, break46 may not be a physical gap betweenfirst section44aandsecond section44b, but rather break46 may be a region of cuttingmember20 having a reduced wall thickness or may comprise a material having an increased flexibility relative to the material of first andsecond sections44a,44b.Break46 also may comprise an exogenous connector that is connected to bothfirst section44aandsecond section44bin order to bridgesections44a,44b. Separation ofsections44a,44bcan increase the flexibility of cuttingmember20 and/or the overall flexibility ofcatheter10.
• Cuttingmembers20 may be made from any suitable material such as a metal, metal alloy, polymer, metal-polymer composite, and the like, or any other suitable material. For example, cuttingmembers20 may be made from stainless steel such as 304V, 304L, or 316L stainless steel. In other embodiments, cuttingmember20 can be made from a glass/KEVLAR® complex material such as ARAMAT®, which is commercially available. Some examples of other suitable materials are listed below in relation toballoon16 andshaft18.
• Balloon16 may be made from typical angioplasty balloon materials including polymers such as polyethylene terephthalate (PET), polyetherimide (PEI), polyethylene (PE), etc. Some other examples of suitable polymers, including lubricious 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), poly(ethylene naphthalenedicarboxylate) (PEN), polysulfone, nylon, perfluoro(propyl vinyl ether) (PFA), other suitable materials, or mixtures, combinations, copolymers thereof, polymer/metal composites, and the like. In some embodiments, it may be desirable to use a relatively non-compliant balloon or a balloon including high modulus or generally stiffer materials so as to reduce balloon elongation. The above list of materials includes some examples of higher modulus materials. Some other examples of 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.Balloon16 may include fiber, particulate material, or other reinforcing filaments. For example,balloon16 may comprise a nanocomposite polymer material.
• Balloon16 may be configured so that it includes one or more “wings” or wing-shaped regions whenballoon16 is deflated. These wings may appear as a plurality of alternating inward and outward radial deflections inballoon16 whenballoon16 is deflated. These wings may be desirable for a number of reasons. For example, by includingballoon16 with wings,balloon16 may have more predictable and consistent re-folding characteristics. Additionally, the wings may be configured so that cuttingmembers20 can be positioned at the inward-most positions of the deflatedballoon16. This arrangement allows cuttingmembers20 to be positioned more closely toshaft18 whenballoon16 is deflated. Accordingly, cuttingmembers20 can be moved away from the vessel walls where they might otherwise result in contact and, possibly, damage to healthy tissue during movement ofcatheter10 within a body lumen. Additionally, alternating the wings and cuttingmembers20 as well as positioning cuttingmembers20 relatively close toshaft18 may allow the wings to fold over andcover cutting members20 whenballoon16 is deflated. Again, this feature may reduce the exposure of cuttingmembers20 to the blood vessel.
• Balloon16 additionally may include one or more discrete points or areas of flexibility such as generally circumferentially extendingcrease70 formed in the wall ofballoon16. Asingle crease70 is shown inFIG. 1; however, two, three, ormore creases70 may be present inballoon16 to provide a desired flexibility to a distal region ofcatheter10.Crease70 may provide increased flexibility to the distal portion ofcatheter10 includingballoon16 during delivery, deployment, and withdrawal of a medical device within a vasculature.Crease70 may allowballoon16 havingcutting members20 to readily bend through a curved vascular pathway and maintain conformity to a vessel lumen during inflation ofballoon16 at a target location. Balloons not having such flexibility may tend to straighten as they are inflated in a curved vascular pathway, thereby placing uneven pressure on the wall of the vessel and/or causing unnecessary trauma to the vessel.
• Crease70 may be a circumferential crease, a helical crease, or the like. For example,crease70 may be disposed substantially orthogonal to cuttingmember20 or at an angle thereto. For instance,crease70 may be formed at a 45-, 60-, 75-, 80- or 90-degree angle relative to cuttingmember20. Preferably,crease70 corresponds withbreak46 in cuttingmember20. For example, cuttingmember20 may be positioned onballoon16 such that break46 of cuttingmember20 is aligned withcrease70. As shown inFIG. 1,first section44amay be positioned proximal ofcrease70 andsecond section44bmay be positioned distal ofcrease70, such thatbreak46 is substantially aligned withcrease70.
• Crease70 may be formed inballoon16 during a molding process, such as a blow molding process, prior to placingcutting members20 onballoon16. Alternatively,crease70 may be formed inballoon16 during a balloon folding operation subsequent to placingcutting members20 onballoon16. A balloon folding fixture may include means for creasingballoon16, such as notches, ridges, and the like. Theballoon16 may be positioned in a folding fixture such that break46 of cuttingmember20 is aligned with the means for creasingballoon16. In this process,crease70 may be fashioned in theballoon16 during a final folding operation. Alternatively or additionally,crease70 may be formed by grinding, laser ablating, chemical etching, or ablation and subsequent back fill with a more compliant material, for example.
• Crease70 may be located on theouter surface40 ofballoon16 or on the inner surface (not shown) ofballoon16.Crease70 may be a fold created inballoon16. Alternatively,crease70 may be defined as a portion ofballoon16 having a reduced wall thickness, a groove, a reduced diameter portion, or recessed area defined in the wall ofballoon16, for example.Crease70 may also be a portion ofballoon16 comprising a material relatively resistant to expansion. Additionally,crease70 may be formed by a band of relatively non-expandable material disposed about a portion ofballoon16 or incorporated in a portion ofballoon16. The band of relatively non-expandable material may constrain a portion ofballoon16 from readily expanding to the extent of adjacent regions.
• It is also contemplated thatballoon16 may additionally and/or alternatively include at least onecrease70 not aligned with abreak46 in cuttingmembers20. Such acrease70 may provide enhanced flexibility along at least a portion ofballoon16. Some further discussion ofcrease70 and other examples, features, and modifications are described in more detail below.
• Shaft18 may be a catheter shaft, similar to typical catheter shafts. For example,shaft18 may include aninner tubular member24 and outertubular member26.Tubular members24/26 may be manufactured from a number of different materials. For example,tubular members24/26 may 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 as300 series stainless steel (including 304V, 304L, and 316L); 400 series martensitic stainless steel; tool 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, monel400, inconel825, or the like; or other suitable material. Some examples of suitable polymers include those described above in relation toballoon16. For example,tubular members24/26 may comprise a reinforced polymer material such as a nanocomposite polymer material. Of course, any other polymer or other suitable material including ceramics may be used without departing from the spirit of the invention. The materials used to manufacture innertubular member24 may be the same as or be different from the materials used to manufacture outertubular member26. Those materials listed herein may also be used for manufacturing other components ofcatheter10 including cuttingmembers20.
• Tubular members24/26 may be arranged in any appropriate way. For example, in some embodiments,inner tubular member24 can be disposed coaxially within outertubular member26. According to these embodiments, inner and outertubular members24/26 may or may not be secured to one another along the general longitudinal axis ofshaft18. Alternatively,inner tubular member24 may follow the inner wall or otherwise be disposed adjacent the inner wall of outertubular member26. Again, inner and outertubular members24/26 may or may not be secured to one another. For example, inner and outertubular members24/26 may be bonded, welded (including tack welding or any other welding technique), or otherwise secured at a bond point. In some embodiments, the bond point may be generally disposed near the distal end ofshaft18. However, one or more bond points may be disposed at any position alongshaft18. The bond may desirably impact, for example, the stability and the ability oftubular members24/26 to maintain their position relative to one another. In still other embodiments, inner and outertubular member24/26 may be adjacent to and substantially parallel to one another so that they are non-overlapping. In these embodiments,shaft18 may include an outer sheath that is disposed overtubular members24/26.
• Innertubular member24 may include aninner lumen28. In at least some embodiments,inner lumen28 is a guidewire lumen. Accordingly,catheter10 can be advanced overguidewire22 to the desired location. The guidewire lumen may extend along essentially the entire length ofcatheter shaft18 so thatcatheter10 resembles a traditional “over-the-wire” catheter. Alternatively, the guidewire lumen may extend along only a portion ofshaft18 so thatcatheter10 resembles a “single-operator-exchange” or “rapid-exchange” catheter. Regardless of which type of catheter is contemplated,catheter10 may be configured so thatballoon16 is disposed over at least a region ofinner lumen28. In at least some of these embodiments, inner lumen28 (i.e., the portion ofinner lumen28 thatballoon16 is disposed over) may be substantially coaxial withballoon16.
• Shaft18 may also include aninflation lumen30 that may be used, for example, to transport inflation media to and fromballoon16. The location and position ofinflation lumen30 may vary, depending on the configuration oftubular members24/26. For example, when outertubular member26 is disposed over innertubular member24,inflation lumen30 may be defined within the space betweentubular members24/26. Moreover, depending on the position of innertubular member24 within outertubular member26, the shape of lumen30 (i.e., the shape adjacent shaft18) may vary. For example, if innertubular member24 is attached to or disposed adjacent to the inside surface of outertubular member26, theninflation lumen30 may be generally half-moon in shape; whereas, if innertubular member24 is generally coaxial with outertubular member26, theninflation lumen30 may be generally ring-shaped or annular in shape. It can be appreciated that if outertubular member26 is disposed alongside innertubular member24, then lumen30 may be the lumen of outertubular member26 or it may be the space defined between the outer surface oftubular members24/26 and the outer sheath disposed thereover.
• Balloon16 may be coupled tocatheter shaft18 in any of a number of suitable ways. For example,balloon16 may be adhesively or thermally bonded toshaft18. Such bonding techniques may include laser welding, heat shrinking, adhesive, and tie layers, for example. In some embodiments, aproximal waist32 ofballoon16 may be bonded toshaft18, for example, at outertubular member26, and adistal waist34 may be bonded toshaft18, for example, at innertubular member24. The exact bonding positions, however, may vary. It can be appreciated that a section ofproximal waist32 may not havesections36 extending therefrom in order for suitable bonding betweenballoon16 and outertubular member30.
• In addition to some of the structures described above,shaft18 may also include a number of other structural elements, including those typically associated with catheter shafts. For example,shaft18 may include a radiopaque marker coupled thereto that may aid a user in determining the location ofcatheter10 within the vasculature. In addition,catheter10 may include a folding spring (not shown) coupled toballoon16, for example, adjacentproximal waist32, which may further help in balloon folding and refolding. A description of a suitable folding spring can be found in U.S. Pat. No. 6,425,882, the disclosure of which is incorporated herein by reference.
• An exploded view illustrating the attachment of cuttingmember20 to balloon16 is shown inFIG. 2. Here it can be seen that a joining member orpolymeric strip38 may be coupled to cuttingmember20 and to balloon16. Joiningmember38 may be formed from a generally flexible or soft material that allows the interface between cuttingmember20 andballoon16 to be somewhat elastic or pliable. For example, joiningmember38 may be manufactured from a low durometer polyurethane or any other suitable material (including any of the polymers and other materials disclosed herein). Accordingly, cuttingmember20 may be securely coupled toballoon16 while still being able to move laterally about eight degrees or less. In addition, different portions of cuttingmember20 may be able to bend or flex, while other portions remain essentially unchanged.
• In at least some embodiments, joiningmember38 may be attached to and disposed between cuttingmember20 andballoon16. For example, joiningmember38 may be attached to anouter surface40 ofballoon16 and to abase50 of the cuttingmember20. The attachment of joiningmember38 with cuttingmember20 andballoon16 may be achieved in any appropriate manner, such as by adhesive bonding, casting, thermal bonding, mechanically connecting, welding, brazing, and the like, or in any other suitable way. The attachment means need not be the same for the attachment between cuttingmember20 and joiningmember38 as the means used to attachballoon16 and joiningmember38.
• Balloon16 may include a discrete region of flexibility such ascrease70 formed in theouter surface40 ofballoon16.Break46 of cuttingmember20 may be aligned withcrease70 such that the increased flexibility ofballoon16 provided bycrease70 may be combined with the increased flexibility of cuttingmember20 provided bybreak46. The enhanced flexibility ofballoon16 may improve the deliverability of the catheter, as well as the conformity ofballoon16 to a vessel lumen curvature during inflation ofballoon16.
• FIG. 3 depicts a partial perspective view of anothercatheter110 that is similar tocatheter10.Catheter110 includes cuttingmembers120 disposed aboutballoon16 in a tandem arrangement. In other words, two cuttingmembers120 may be arranged end-to-end to define an elongated cutting surface. This embodiment may increase the flexibility of cuttingmembers120 by dividing what might otherwise be a single cutting blade into multiple discrete sections. Thus, the cuttingmembers120 may individually have a shortened length, makingballoon16 more amenable to bending or flexing. It can be appreciated that the precise arrangement of cuttingmembers120 is not intended to be limited to a tandem configuration. For example, cuttingmembers120 may have an arrangement that is longitudinally offset. Additionally,catheter110 is not limited to pairs of cuttingmembers120, as any suitable number of cuttingmembers120 may be used without departing from the spirit of the invention.
• It can also be seen inFIG. 3 that cuttingmembers120 may be positioned on either side ofcrease70 inballoon16. As illustrated in this embodiment,crease70 may be a reduced diameter portion or material offset ofballoon16.Crease70 provides increased flexibility to theballoon16. Placing cuttingmembers120 on either side ofcrease70 provides flexibility to theballoon16 while maintaining sufficient functionality ofballoon16 necessary to perform a medical procedure at a target location. Joiningmember38 may extend overcrease70, or joiningmember38 may terminateproximate crease70. Alternatively, joiningmember38 may be absent fromcatheter assembly110.
• FIG. 4 depicts a perspective view of acatheter210 similar tocatheter10.Catheter210 includes aballoon216 disposed about a distal region ofcatheter210.Balloon216 includes ahelical crease270 disposed about theouter surface240 ofballoon216. Cuttingmembers220 may be arranged aboutballoon216 such that cuttingmembers220 are coupled away fromcrease270. In other words, cuttingmembers220 are positioned such that they do not extend overhelical crease270. Alternately, cuttingmembers220 may extend substantially the length ofballoon216, thereby traversingcrease270.Helical crease270 may provide increased flexibility of theballoon216 during a medical procedure.
• FIG. 5 is a perspective view of acatheter310 similar tocatheter10.Balloon316 may include a plurality ofcreases370. As shown inFIG. 5,balloon316 may include twocreases370 extending around the circumference ofballoon316. However, it should be recognized thatballoon316 may includeadditional creases370. A plurality of cuttingmembers320 may be coupled to theballoon316. Preferably, cuttingmembers320 are coupled equidistantly aboutballoon316. Cuttingmember320 may extend substantially the length ofballoon316 or a portion thereof. As shown inFIG. 5, cuttingmember320 may include a plurality of integral segments separated with abreak346 therebetween. Each cuttingmember320 is positioned such thatbreak346 is aligned withcrease370. In other words, cuttingmember320 may be positioned such thatbreak346 is located at the same longitudinal position alongballoon316 ascrease370. Aligningbreak346 withcrease370 providesballoon316 with defined flexibility regions along its length.
• FIG. 6 depicts a perspective view ofcatheter410 similar tocatheter10.Catheter410 includes anexpandable member416 including at least onecrease470.Crease470 may be a portion ofexpandable member416 having a reduced diameter relative toproximal balloon section430 anddistal balloon section440. A plurality of cuttingmembers420 may be coupled toballoon416. Each cuttingmember420 may extend along substantially the length ofproximal section430 ordistal section440, thereby leavingcrease470 free of cuttingmembers420. Therefore, a flexibility region may be formed atcrease470 to impart greater flexibility inballoon416.
• FIG. 7 shows a representative catheter disposed in a vessel having a curved profile.Catheter410 is shown inFIG. 7; however,catheter410 may be replaced with other representative embodiments or any combination thereof disclosed herein.Catheter410 may be advanced through the vasculature overguidewire422 untilexpandable member416 reaches a target location such asstenosis414.Stenosis414 may be located in a curved portion ofvessel412. Asexpandable member416 is expanded, cuttingmembers420 may contactstenosis414.Crease470 allowsexpandable member416 to maintain a curved profile while being expanded. Therefore, cuttingmembers420 may contactstenosis414 along a longer portion of the curved region, reducing trauma to thevessel412 and/or minimizing the need for additional procedures. Additionally, pressure withinexpandable member416 may be more evenly transmitted throughoutexpandable member416 whenexpandable member416 conforms to the curvature ofvessel412 attributable at least in part tocrease470. Therefore, cuttingmembers420 may contactstenosis414 more uniformly and along a longer portion of their length.
• FIG. 8 shows acatheter510 including a multi-lobed balloon516. Multi-lobed balloon516 includes three segments orlobes516a,516b,516c. However, balloon516 may include two, three, four, five, six or more lobes. Multi-lobed balloon516 may be coupled to a distal portion ofcatheter510. Lobes may be formed in balloon516 in a variety of ways. For example, aband575 may be disposed about a portion of balloon516 restraining a portion of balloon516 from expanding, thereby allowing a portion of balloon516 to expand while constraining an adjacent portion byband575. Band575 may be a discrete, relatively non-expandable member disposed about a portion of balloon516. Instead, balloon may be made of a material having alternating portions. Forexample band575 may be a portion of balloon516 including a relatively non-expandable material whilelobes516a,516b,516cmay include a relatively expandable material. Alternatively or additionally,band575 may be a portion of balloon516 of a greater thickness thanadjacent lobes516a,516b,516c. Portions of material of a greater thickness may not expand as readily as adjacent areas having a thinner thickness, thereby allowinglobes516a,516b,516cto expand whileband575 retains a reduced cross-sectioned profile.
• One ormore cutting members520 may be coupled to balloon516. As shown inFIG. 8, the one ormore cutting members520 may extend substantially the length of balloon516. Alternatively, cuttingmembers520 may individually be coupled to one oflobes516a,516b,516c, therefore not extending over a reducedcross-sectioned region570. Cuttingmembers520 may include one or more flexibility regions or breaks546 for increased flexibility. Preferably, break546 in cuttingmember520 may be aligned with reducedcross-sectioned region570 to impart enhanced flexibility tocatheter510. In other words, cuttingmember520 may be positioned such that break546 is located at the same longitudinal position of balloon516 asband575. Such an arrangement may providecatheter510 with sufficient flexibility to navigate a tortuous vasculature and retain a curved configuration during inflation of balloon516 at a target location.
• FIG. 9 shows acatheter610 having adistal portion630 including a plurality ofballoons616a,616b. AlthoughFIG. 9 shows acatheter610 having twoballoons616a,616b, it is contemplated thatcatheter610 may include two, three, four, five, six or more balloons616.Proximal balloon616amay be secured tocatheter610 atproximal waist611 andintermediate waist615.Distal balloon616bmay be secured tocatheter610 atdistal waist613 andintermediate waist615.Intermediate waist615 may be a portion ofproximal balloon616a,distal balloon616b, orintermediate waist615 may be a portion shared withproximal balloon616aanddistal balloon616b.Balloon616amay be integrally connected withballoon616bbyintermediate waist615.Intermediate waist615 may be secured tocatheter610 in any of a number of suitable ways. For example,intermediate waist615 may be adhesively or thermally bonded tocatheter610, orintermediate waist615 may be secured tocatheter610 by a discrete member such as a heat shrink tube, coupler, generally inelastic member, or the like. Such bonding techniques may include laser welding, heat shrinking, adhesive, and tie layers, for example. Alternatively, balloons616a,616bmay comprise two discrete elements each having anintermediate waist615 secured tocatheter610.Balloons616a,616bmay be independently expanded, expanded simultaneously, or expanded in series.
• A plurality of cuttingmembers620 may be coupled toballoons616a,616b. Preferably, eachballoon616a,616bmay include three cuttingmembers620 disposed equidistantly aboutballoon616a,616b. However, eachballoon616a,616bmay include one, two, three, four, five, six ormore cutting members620.
• Intermediate waist615 may define a reducedcross-sectioned region670 ofdistal portion630 ofcatheter610 whileballoons616a,616bare expanded. Therefore, reducedcross-sectioned region670 may provide a discrete point of flexibility in thedistal region630 ofcatheter610. In an expanded state, thedistal region630 ofcatheter610 may readily conform to the curvature of a vessel due to a discrete point offlexibility670 provided byintermediate waist615. The enhanced flexibility ofdistal portion630 may allow expansion ofballoons616a,616bwithin a vessel without surrendering compliance to a curvature of a vessel. Therefore,catheter610 may be designed to sufficiently treat a stenosis located in a sharply curved portion of a vessel.
• Those skilled in the art will recognize that the present invention may be manifested in a variety of forms other than the specific embodiments described and contemplated herein. It is contemplated that one may combine, substitute, or modify specific elements of the various embodiments described herein without departing from the scope and spirit of the invention. Accordingly, departure in form and detail may be made without departing from the scope and spirit of the present invention as described in the appended claims.

Claims (28)

1. A medical device comprising:

an elongate shaft having a distal region;

an expandable member coupled to the distal region of the elongate shaft;

a plurality of cutting members coupled to the expandable member, wherein each cutting member includes a plurality of segments, wherein each segment is separated by a break; and

wherein the expandable member includes discrete generally circumferential area of flexibility.

2. The medical device ofclaim 1, wherein the discrete area of flexibility is a circumferential crease.

3. The medical device ofclaim 2, wherein the circumferential crease is orthogonal to the plurality of cutting members.

4. The medical device ofclaim 1, wherein the discrete area of flexibility is a helical crease.

5. The medical device ofclaim 1, wherein the expandable member includes an outer surface, wherein the discrete area of flexibility is formed in the outer surface of the expandable member.

6. The medical device ofclaim 1, wherein the expandable member includes an inner surface, wherein the discrete area of flexibility is formed in the inner surface of the expandable member.

7. The medical device ofclaim 1, wherein the discrete area of flexibility is defined by a reduced wall thickness of the expandable member.

8. The medical device ofclaim 1, wherein the discrete area of flexibility is defined by a reduced diameter portion.

9. The medical device ofclaim 1, wherein the discrete area of flexibility includes a relatively non-expandable band of material.

10. The medical device ofclaim 1, wherein each cutting member includes a cutting edge, wherein the break is defined as a gap in the cutting edge.

11. A medical device comprising:

an elongate shaft having a distal region;

an expandable member coupled to the distal region of the elongate shaft;

one or more cutting members coupled to the expandable member; and

wherein the expandable member includes at least one generally circumferential crease.

12. The medical device ofclaim 11, wherein each cutting member includes a first segment, a second segment and a break located between the first and second segments.

13. The medical device ofclaim 12, wherein each circumferential crease is aligned with the break of the one or more cutting members.

14. The medical device ofclaim 11, wherein each cutting member includes a relatively more flexible region, wherein the one or more circumferential creases are aligned with the relatively more flexible region of each cutting member.

15. The medical device ofclaim 11, wherein each cutting member includes a reduced thickness area, wherein the one or more circumferential creases are aligned with the reduced thickness area.

16. The medical device ofclaim 11, wherein the expandable member includes a relatively non-compliant material.

17. The medical device ofclaim 11, wherein the one or more creases are a recessed area of the expandable member.

18. The medical device ofclaim 11, wherein the one or more creases are a reduced diameter portion of the expandable member.

19. The medical device ofclaim 11, wherein the one or more cutting members traverse the one or more circumferential creases.

20. The medical device ofclaim 11, wherein the one or more circumferential creases are free of the one or more cutting members.

21. The medical device ofclaim 11, wherein the one or more circumferential creases are orthogonal to the one or more cutting members.

22. An atherotomy device comprising:

an elongate shaft having a distal region;

an expandable member coupled to the distal region of the elongate shaft;

a plurality of atherotomes disposed about the expandable member, each atherotome including a cutting edge and at least one break in the cutting edge; and

wherein the expandable member includes a generally circumferential crease at the at least one break.

23. The atherotomy device ofclaim 22, wherein the plurality of atherotomes are disposed equidistantly about the expandable member.

24. The atherotomy device ofclaim 22, wherein each atherotome includes a plurality of segments, wherein the plurality of segments is separated by the break.

25. The atherotomy device ofclaim 22, wherein the circumferential crease is defined by a reduced wall thickness of the expandable member.

26. The atherotomy device ofclaim 22, wherein the circumferential crease is a groove formed in an outer wall of the expandable member.

27. The atherotomy device ofclaim 22, wherein the circumferential crease is a reduced diameter portion of the expandable member.

28. The atherotomy device ofclaim 22, wherein the circumferential crease is orthogonal to the plurality of atherotomes.

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