FIELD OF THE DISCLOSURE

[0001] The present disclosure generally relates to a material-removing machine for removing material from a cone section of a medical balloon and a process for removing material from the cone section.

BACKGROUND OF THE DISCLOSURE

[0002] Balloons mounted on the distal ends of catheters are widely used in medical treatment. The balloon may be used to widen a vessel into which the catheter is inserted, open a blocked vessel and/or deliver a medical device to a body location among other uses. The medical balloon includes a central body section, which is typically tubular, opposite cone sections at opposite longitudinal ends of the body section, and opposite waist sections at opposite longitudinal ends of the balloon. In use, the uninflated balloon is delivered to a treatment location within a body lumen (e.g., a blood vessel) by tracking through an introducer sheath and exiting a distal end of the sheath to reach the treatment location. Once the uninflated balloon has reached the treatment location, fluid is delivered into the balloon, thereby expanding the outer circumference of the balloon (i.e., balloon is inflated). After treatment, the balloon is deflated and "pulled back" into the introducer sheath. The balloon catheter can then be withdrawn from the mtroducer sheath and the patient's body. It may be necessary or desired to re-introduce the balloon catheter into a body lumen, through the introducer sheath, to further treat the body lumen.

[0003] One known method of forming a medical bal loon involves blow molding. In particular, the balloon is formed by radially expanding a segment of extruded polymer tubing, called a parison, in a moid. Balloons produced by radially expanding a parison typically have thicker waist sections and cone sections than the thickness of their body sections. The thicker cone sections may interfere with refolding of the balloon upon deflation (i.e., after treatment), which can make it difficult to pull the balloon back into the introducer sheath. This interference with re-folding may also make it difficult for the user to re-introduce the deflated balloon into the sheath after withdrawing the balloon catheter from the patient's body. SUMMARY OF THE DISCLOSURE

[00Θ4] In one aspect, a material-removing machine for removing material from a cone section of a medical balloon generally comprises a material -removing element operative!}'" connected to a prime mover such that operation of the prime mover imparts rotation to the materia] -removing element about a rotational axis. The material-removing element includes an interior surface defining a generally conical-shaped cavity extending along the rotational axis and adapted to receive at least a longitudinal portion of a cone section of an expanded medical balloon for removing material from the longitudinal portion of the cone section to reduce a wall thickness of the cone section. Material may be continuously removed around a 360-degree exterior perimeter of the longitudinal portion of the cone section of the medical balloon to red uc e the thickness of the balloon wall defining the cone section.

[00Θ5] Other features will be in part apparent and in part pointed out hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 is a perspective of one embodiment of a medical bal loon for a balloon catheter;

[0007] FIG. 2 is a fragmentary perspective of a balloon catheter including the balloon of FIG. 1 ;

[0008] FIG . 3 is an enlarged, fragmentary side eievationai view of the balloon of FIG. 1 , showing a proximal cone section, a portion of a proximal waist section, and a portion of the body section thereof;

[0009] FIG. 4 is an enlarged, fragmentary section of the bal loon taken along the line 4-4 in FIG. 3;

[0Θ1Θ] FIG . 5 is an enlarged, fragmentary section of the balloon, similar to FIG. 4, before removing material from the proximal cone section;

[0011] FIG. 6 is a perspective of a material-removing machine;

[0012] FIG. 7 is a cross section of the material-removing machine taken through the line 7—7 in FIG . 6;

[0013] FIG. 8 is similar to FIG. 7, additionally including a cross section of an expanded medical balloon received in the material -removing machine; [0014] FIG. 9 is a front elevation of an embodiment of a materia] -removing element of the material-removing machine;

[0015] FIG. 10 is a perspective of another embodiment of a material-removing element; and

[0016] FIG. 11 is a perspective of yet another embodiment of a material- removing element.

[0017] Corresponding reference characters indicate corresponding parts throughout the drawings.

DETAILED DESCRIPTION OF THE DRAWINGS

[0018] Referring to FIG. 1 , one embodiment of a medical balloon for a medical device is generally indicated at reference numeral 12 in FIG. 1. The balloon defines an interior chamber 14 for receiving fluid therein to expand an outer circumference (i.e., an outer perimeter) of the balloon. The balloon 12 is shown in its expanded or inflated configuration throughout the drawings, with the understanding that in its non-expanded configuration (e.g., deflated configuration or uninflated configuration), the balloon is capable of folding lengthwise such that the outer circumference of the balloon in its non- expanded configuration is substantially less than the outer circumference of the balloon in its expanded confi guration. With respect to any or all of the below described embodiments of the present disclosure, the medical balloon 12 may be secured to a catheter, generally indicated at 16 in FIG. 2, such that a catheter body 18 of the catheter extends axially through the interior chamber 14 of the balloon, as is generally known in the art, to form a balloon catheter, generally indicated at 20. The balloon 12 and catheter body 18 have suitable shapes and dimensions for introduction into a desired body lumen for treatment therein. Typically, the balloon 12, in its non-expanded initial configuration (e.g., uninflated configuration), is introduced into the body lumen using an introducer sheath (not shown). The non-expanded balloon 12 is delivered to a treatment location within a body lumen (e.g., a blood vessel) by tracking through the introducer sheath and ultimately exiting a distal end of the sheath to reach the treatment location. Once the non-expanded balloon 12 has reached the treatment location, fluid (e.g., saline) is delivered into the balloon, thereby expanding the outer circumference of the balloon (e.g., balloon is inflated). After treatment, the balloon 12 is deflated to its non-expanded configuration and "pulled back" into the introducer sheath . The balloon catheter 20 can then be withdrawn from the introducer sheath and the patient's body. It may be necessary or desired to re -introduce the balloon catheter 20 into a body lumen, through the introducer sheath, to further treat the bod)' lumen.

[001 ] The illustrated balloon catheter 20 may be configured for introduction along and inflation (i.e., circumferential or perimeter expansion) within a blood vessel for treating vascular stenosis. As an example, the medical balloon 12 of the illustrated balloon catheter 20 may be configured for introduction along and expansion within one or more of peripheral arteries and veins, coronary arteries and veins, renal arteries and veins, cerebral arteries and veins, and carotid artery. In other examples, the medical balloon 12 may be configured for introduction along and expansion within other body lumens for treating stenosis of those lumens. The balloon 12 may be configured for treating other body lumens and/or for other treatments of those lumens.

[0020] Referring to FIG. 1 , the medical balloon 12 has a length LI and comprises a balloon body section 24; opposite distal and proximal waist sections 26a, 26b, respectively, at opposite longitudinal ends of the balloon; and opposite distal and proximal cone sections, generally indicated at 28a, 28b, respectively, at corresponding distal and proximal ends of the body section intermediate the body section and the corresponding distal and proximal waist sections. The length LI of the balloon may measure from about 10 mm to about 250 mm. As explained in more detail below, the body section 24, waist sections 26a, 26b, and cone sections 28a, 28b may be integrally formed during a blow molding process to form the balloon 12 as a one-piece

construction. It is understood that the balloon 12 may have other sections, structures, and/or components without departing from the scope of the present invention,

[0021] The balloon 12 may be formed from a polymer material, including, but not limited to, a thermoplastic polymer or a thermoplastic elastomer polymer. For example, suitable materials for the balloon include polyesters such as PET, PEN and PBT; polyurethane block copolymers such as ISOPLAST 301 , PELLETHANE 2363- 75D; polyamide block copolymers such as FEB AX 6333, PEBAX 7033 and PEBAX 7233; polyamides such as nylon 12, nylon 1 1 , and nylon 10; polymer blend materials such as single or multiphase blends of liquid crystal polymers in another polymer; and polyester elastomer balloons such as ARNITEL EM 740 and HYTREL 8238. Other materials do not depart from the scope of the present invention as defined by the claims. In one example, the balloon 12 may be free from a lubricious coating (hydrophobic or hydrophilie), although in other examples the balloon may include such a lubricious coating,

[0022] As shown in FIG. 1, the body section 24 interconnects and is disposed between the distal and proximal cone sections 28a, 28b. In the illustrated embodiment, the body section 24 is generally tubular defining a portion of the interior chamber 14 for receiving fluid to expand an outer circumference (i.e., an outer dimension) of the body section. Referring to FIG. 3, the body section 24 has an expanded inner diameter ID 1 (i.e., an inner cross-sectional dimension) defined by an interior surface 30 of the balloon 12, an expanded outer diameter ODl, and a thickness Tl that may be generally uniform along its length. In one example, the expanded outer diameter ODl may measure greater than or equal to about 3 mm, and in one example, from about 3 mm to about 30 mm, and the single-wall thickness Tl may measure from about 0,0127 mm to about 0.0762 mm. The body section 24 may have other shapes and dimensions without departing from the scope of the present invention.

10023] The distal and proximal waist sections 26a, 26b are general ly tubular and, in the illustrated embodiment, are configured to receive the catheter body 18 therein. Referring to FIG. 3, each waist section 26a, 26b has an outer diameter OD2 less than the outer diameter ODl of the body section 24. Thicknesses T2 of the waist sections 26a, 26b may be greater than the thickness Tl of the body section 24. It is understood that the waist sections 26a, 26b may be omitted from the balloon 12 without departing from the scope of the present invention.

[0024] In general, the distal and proximal cone sections 28a, 28b are mirror images of one another. For purposes of this disclosure, the proximal cone section 28b is shown in detail in the drawings, with the understanding that the teachings relating to the proximal cone section apply equally to the distal cone section 28a, with exceptions noted herein. Referring to FIG. 3, the proximal cone section 28b has distal and proximal ends 36a, 36b, a length L2 extending between the proximal and distal ends, and an exterior surface 40 having a generally conical (e.g., frustoconical) shape and an outer diameter (i.e., an outer cross-sectional dimension) tapering proximal toward the proximal end of the proximal cone section. As shown in FIG. 4, an interior surface 44 of the proximal cone section 28b also has a generally conical shape defining an inner circumference or periphery (i.e., an inner dimension) and an inner diameter (i.e., an inner cross-sectional dimension) of the cone section that taper proximaliy toward its proximal end 36b. A reduced-thickness longitudinal portion (e.g., an apex end margin) of the proximal cone section 28b extending from the proximal end 36b of the cone section toward the distal end 36a thereof has a reduced wall thickness T3. The reduced wall thickness T3 extends around a 360-degree exterior perimeter of the reduced-thickness longitudinal portion of the proximal cone section 28b. As explained in more detail below, the reduced wall thickness T'3 is formed by removing material from an exterior of the proximal cone section 28b. Because of the material removal process, the red ced-thickness longitudinal portion is coarser and more opaque than the remainder of the proximal cone section 28b. Moreover, a step transition 50 is formed on the exterior surface between the reduced- thickness longitudinal portion and the remainder of the proximal cone section 28b. The step transition 50 extends continuously around the 360 degree perimeter of the proximal cone section 28b such that the step transition has an annular shape. In a non-limiting example, the step transition 50 may have a radial dimension rl from about 0.0254 mm to about 0.0508 mm.

[0025] In the illustrated embodiment, the structures of the distal cone section 28a have inverse relationships with the corresponding structures of the proximal cone section 28b. Although not shown in detail in the drawings, the distal cone section 28a has proximal and distal ends, a length extending between the proximal and distal ends, and an exterior surface having a generally conical shape and defining an outer circumference or periphery (i.e., an outer dimension) and an outer diameter (i.e., an outer cross- sectional dimension) of the cone section that taper distally to ward its distal end. An interior surface of the distal cone section 28a also has a generally conical shape and defines an inner circumference or periphery (i.e., an inner dimension) and an inner diameter (i.e., an inner cross-sectional dimension) of the cone section that taper distally toward the distal end thereof. A reduced-thickness longitudinal portion (e.g., the apex end margin) of the distal cone section 28a extending from the distal end of the cone section toward the proximal end thereof has a reduced wall thickness, similar to the reduced wall thickness of the proximal cone section 28b. The reduced wall thickness extends around a 360-degree exterior perimeter of the reduced-thickness longitudinal portion of the distal cone section 28a. As explained in more detail below, the reduced wall thickness is formed by removing material from an exterior surface of the distal cone section 28a. Because of the material removal process, the reduced-thickness longitudinal portion is coarser and more opaque than the remainder of the distal cone section 28a. Moreover, a step transition is formed on the exterior between the reduced-thickness longitudinal portion and the remainder of the distal cone section 28a. The step transition extends continuously around the 360 degree perimeter of the distal cone section 28a such that the step transition has an annular shape. In a non-limiting example, the step transition may have a radial dimension from about 0.0254 mm to about 0.0508 mm.

[0026] A cross section of an embodiment of a blow-molded balloon before removing material from the cone sections according to one embodiment of the present disclose is shown in FIG. 5. As shown in FIG. 5, a wall thickness T4 of the proximal cone section 28b between the interior and exterior surfaces 40, 44 generally increases toward the proximal end 36b thereof and the proximal waist section 26b, such that the proximal cone section has a maximum wall thickness generally adjacent to the proximal waist section. Likewise, a thickness (not indicated) of the distal cone section 28a between the interior and exterior surfaces generally increases toward the distal end thereof and the distal waist section, such that the distal cone section has a maximum wall thickness generally adjacent to the distal waist section. As set forth above, the wall thicknesses T4 of the proximal and di stal cone sections 28a, 28b after blow molding may interfere with refolding of the balloon upon deflation (i.e., after treatment), which can make it difficult to pull the balloon back into the introducer sheath. Accordingly, the following disclosed method and material-removal machine for reducing the wall thickness T4 of at least one of the distal and proximal cone sections 28a, 28b, particularly the proximal cone section such as shown in FIG. 4, also reduces the amount of feree required to pull the balloon 12 back into the introducer sheath.

[0027] Referring to FIG. 6, one embodiment of a material-removing machine is generally indicated at reference numeral 56. The material-removing machine 56 includes a prime mover 58 (e.g., an electric motor), a material-removing element 60 operatively connected to the prime mover such that operation of the prime mover imparts rotation to the material-removing element about a rotational axis Al , and a base, generally indicated at 62, to which the prime mover and the material-removing element are secured. In the illustrated embodiment, the prime mover 58 imparts rotation to the material -removing element 60 via a belt and pulley system, generally indicated at 66. The belt and pulley system 66 includes a driver pulley 68 mounted on a first pair of mounts 70 of the base 62, a dri ven pulley 72 mounted on a second pair of mounts 74, and a belt 78 connecting the driver and driven pulleys. The illustrated material-removing machine 56 also includes a belt tensioning mechanism, generally indicated at 80, to allow variable tensioning of the belt 78. The driver pulley 68 is fixed to and rotationally driven by the prime mover 58. Torque is transmitted from the driver pulley 68 to the driven pulley 72 via the belt 78. The driven pulley 72 is fixed to a drive shaft 82, which is in turn fixed to the material-removing element 60. Accordingly, the driven pulley 72 transmits torque to the drive shaft 82, which transmits torque to the material-removmg element 60 for rotating the material-removmg element about the rotational axis Al . As shown in FIG. 7, the drive shaft 82 is secured to the mounts 74 of the base 62 via radial bearings 86 and a thrust bearing 88 such that the drive shaft is rotatable relative to the base about the rotational axis Al . In other embodiments, the material -removing machine 56 may include a drive system other than the belt and pulley system 66, such as a direct drive system,

[0028] As shown in FIG. 7, the material-removmg element 60 includes an interior surface 90 defining a generally conical-shaped cavity 92 extending along the rotational axis Al and adapted to receive at least a longitudinal portion of a cone section 28a, 28b of the expanded medical balloon 12. At least a portion of the interior surface 90 is adapted to remove material from the longitudinal portion of the cone section 28a, 28b to reduce the wail thickness of the longitudinal portion. In one embodiment, at least a portion of the interior surface 90 of the material-removing element 60 may be defined by one or more abrasive elements for abrading the cone section 28a, 28b as the material- removing element rotates about the rotational axis Al . For example, as shown in FIG. 9, a plurality of abrading elements 96 (e.g., burrs) may define a portion of the interior surface 90. The material-removing element 60 also defines a through opening 100 in communication with the conical-shaped cavity 92. The through opening 100 is sized and shaped for receiving the waist section 26a, 26b of the expanded medical balloon 12 when the corresponding cone section 28a, 28b of the balloon is received in the conical -shaped cavity 92. The through opening 100 is also in communication with a passage 102 extending axially within the drive shaft 82. The passage 102 is configured to receive a shaft (e.g., the catheter body 18) that is secured to the proximal end of the balloon 12. The shaft 18 allows the balloon 12 to be expanded (e.g., inflated) during removal of materia! from one or more of the cones 28a, 28b. in the illustrated embodiment, the material-removmg element 60 is removably secured to the drive shaft 82 via a set screw (not shown) or in other ways.

[0029] In another embodiment, at least a portion of the interior surface 90 of the material-removing element 60 may be defined by one or more cutting elements for cutting the cone section 28a, 28b as the material-removmg element rotates about the rotational axis A! . For example, in the embodiment shown in FIG. 10, an interior surface 90' of a material-removing el ement 60' includes straight grooves 98 defining ribs for removing material. In another example shown in FIG. 11, an interior surface 90" of a material-removing element 60" includes crossing helical grooves 99 defining a knurled surface for removing material. The material-removing element may include other elements for removing material from the cone section 28a, 28b.

[0030] In an exemplary method, material is removed from one or both of the cone sections 28a, 28b of an expanded medical balloon 12 using the illustrated material- removing machine 56, for example. The medical balloon 12 is expanded (e.g., inflated) into its expanded configuration by delivering a fluid (e.g., saline) into the interior chamber 14 of the medical balloon. The medical balloon 12 may be expanded before, during or after insertion of the respective cone section 28a, 28b into the conical -shaped cavity 92 of the material -removing element 60. in one example when removing material from the proximal cone section 28b,the shaft (e.g., catheter body 18) attached to the uninflated medical balloon 12 is first inserted through the conical -shaped cavity 92 and through the axial passage 102 of the drive shaft 82 such that a proximal end margin of the shaft extends through an open free end of the drive shaft. A holder (not shown) may ^¬ be configured to hold or pull the free end of the waist section 26b such that the proximal cone section 28b is received and held within the conical-shaped cavity 92 and the proximal waist section 26b is received in the through opening 100. In another example when removing material from the distal cone section 28a, the distal cone section is received within the conical-shaped cavity 92 and the distal waist section 26a is inserted into the through opening 100. The medical balloon 12 may be expanded before, during or after insertion of the respective cone section 28a, 28b into the conical-shaped cavity 92 of the material-removing element 60. In one example, the medical balloon 12 is expanded after the cone section 28a, 28b is received in the conical-shape cavity 92. Moreover, in the illustrated embodi m ent, only the longitudi nal portion of the cone section 28b is received in the material-removing element 60.

[0031] Referring to FIG. 8, with the medical balloon 12 in its expanded configuration and the cone section 28b received in the material-removing element 60, the prime mover 58 is operated to rotate the material -removing element about the rotational axis Al . In a non-limiting example, the material removing element 60 may have a rotational speed from about 5,000 rpm to about 10,000 rpm. As the materia] -removing element 60 rotates about the cone section 28b, the material-removing element removes material continuously from the 360-degree exterior perimeter of the longitudinal portion of the cone section to reduce the wall thickness of the cone section. As a non-limiting example, the material-removing element 60 may be configured to remove from about 0.0254 mm to about 0.0508 mm of wall thickness from the 360-degree exterior perimeter of the longitudinal portion of the cone section 28b. The resulting cone section 28b may have the appearance and structure of the cone section 28b as described above wi th respect to FIG. 4. After removing material from the cone section 28b, material may be removed from the other cone section 28a in the same manner.

[0032] Having described the invention in detail, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims.

[0033] When introducing elements of the present invention or the preferred embodiment(s) thereof, the articles "a", "an", "the" and "said" are intended to mean that there are one or more of the elements. The terms "comprising", "including" and

"having" are intended to be inclusive and mean that there may be additional elements other than the listed elements.

[0034] As various changes could be made in the above constructions, products, and methods without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.