Patent Publication Number: US-2018036032-A1

Title: Expandable scaffold with cutting elements mounted thereto

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 13/571,552, filed on Aug. 10, 2012, which claims the benefit of U.S. Provisional Application No. 61/522,453, filed on Aug. 11, 2011, the entire disclosures of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The disclosure is directed to expandable scaffolds with cutting elements mounted thereto to score or cut stenotic lesions in a blood vessel. More particularly, the disclosure is directed to self-expanding scaffolds with cutting elements mounted thereto and balloon catheters insertable within the scaffold to radially expand the cutting elements against a stenotic lesion. 
     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, or lack of oxygenation and/or circulation to other regions of the body. 
     Occluded, stenotic, or narrowed blood vessels, as well as native or synthetic arteriovenous dialysis fistulae, may be treated in a recanalization procedure, such as with an angioplasty balloon catheter advanced over a guidewire to an occlusion so that the balloon is positioned across the occlusion. The balloon is then inflated to enlarge the passageway through the occlusion. 
     One of the major obstacles in treating coronary artery disease and/or treating blocked blood vessels or fistulae is re-stenosis or re-narrowing of the passageway through the occlusion subsequent to an angioplasty procedure or other recanalization procedure. Evidence has shown that cutting or scoring the stenosis, for example, with an angioplasty balloon equipped with a cutting element, during treatment can reduce incidence of re-stenosis. Additionally, cutting or scoring the stenosis may reduce trauma at the treatment site and/or may reduce the trauma to adjacent healthy tissue. Cutting elements may also be beneficial additions to angioplasty procedures when the targeted occlusion is hardened, fibrotic 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 elements having cutting edges have been developed to attempt to enhance angioplasty treatments. Existing cutting elements tend to be fairly rigid. The rigid structure of the cutting elements limits the flexibility of the balloon, thereby limiting the ability of the cutting element, and the balloon to which it is mounted, to navigate through a tortuous vasculature of a patient. 
     Accordingly, there is an ongoing need for delivering cutting elements for use in angioplasty treatments, and methods of incising a stenosis with cutting elements provided with a medical device. Namely, it would be desirable to provide an expandable structure for use with an angioplasty balloon to position cutting elements proximate a stenotic lesion that is flexible for navigating tortuous anatomy. 
     SUMMARY 
     The disclosure is directed to several alternative designs, materials and methods of manufacturing medical device structures and assemblies, and the uses thereof. 
     Accordingly, one illustrative embodiment is a medical device assembly for incising a stenosis in a blood vessel. The medical device assembly includes a self-expanding scaffold configured to be expandable from a first contracted configuration to a second expanded configuration. The self-expanding scaffold is biased toward the second expanded configuration. A cutting element is secured to the self-expanding scaffold and extends radially outward therefrom. The assembly further includes a sheath having a lumen therein. The self-expanding scaffold is positionable in the lumen of the sheath in the first contracted configuration. An elongate member extends proximally from the self-expanding scaffold through the lumen of the sheath. The self-expanding scaffold is constrained in the lumen of the sheath to maintain the self-expanding scaffold in the first contracted configuration and deployed out of the lumen of the sheath to permit the self-expanding scaffold to expand to the second expanded configuration. 
     Another illustrative embodiment is a medical device assembly for incising a stenosis in a blood vessel. The medical device assembly includes an incising device, a tubular sheath, and a catheter having an inflatable balloon mounted thereon. The incising device includes an expandable scaffold having a plurality of cutting elements projecting radially outward therefrom, and an elongate member extending proximally from the expandable scaffold to be manipulated by a user. The expandable scaffold is positionable in the lumen of the tubular sheath in a contracted configuration with the plurality of cutting elements engaged with an interior of the tubular sheath. The inflatable balloon of the catheter is configured to be advanced distally into an interior of the expandable scaffold through a proximal opening of the expandable scaffold, and inflation of the inflatable balloon urges the cutting elements radially outward to incise a stenosis. 
     Yet another illustrative embodiment is a method of incising a stenosis in a blood vessel. The method includes advancing a self-expanding scaffold of an incising device in a contracted configuration within a lumen of a tubular sheath to a stenosis in a blood vessel. The self-expanding scaffold includes a plurality of cutting elements projecting radially outward therefrom. The tubular sheath is withdrawn from the self-expanding scaffold to permit the self-expanding scaffold to automatically expand radially outward to an expanded configuration to urge the cutting elements against the stenosis. A deflated balloon of a balloon catheter is advanced into an interior of the self-expanding scaffold through a proximal opening of the self-expanding scaffold with the self-expanding scaffold in the expanded configuration. The balloon is then inflated to press against the interior of the self-expanding scaffold and press the cutting elements into the stenosis. 
     The above summary of some example embodiments is not intended to describe each disclosed embodiment or every implementation of the aspects of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The aspects of the disclosure may be more completely understood in consideration of the following detailed description of various embodiments in connection with the accompanying drawings, in which: 
         FIG. 1  is a side view of an exemplary system with cutting elements for incising a stenotic lesion; 
         FIG. 1A  is a cross-sectional view of the cutting device of  FIG. 1  taken along line  1 A- 1 A; 
         FIG. 1B  is a side view of an alternative arrangement of cutting elements mounted on the incising device of  FIG. 1 ; 
         FIG. 2  is a side view of another exemplary system with cutting elements for incising a stenotic lesion; 
         FIG. 2A  is a cross-sectional view of the cutting device of  FIG. 2  taken along line  2 A- 2 A; 
         FIG. 3  is a side view of another exemplary system with cutting elements for incising a stenotic lesion; 
         FIG. 3A  is a cross-sectional view of the cutting device of  FIG. 3  taken along line  3 A- 3 A; 
         FIGS. 4-8  illustrate an exemplary method of treating a stenotic lesion with an expandable scaffold with cutting elements in cooperation with an inflatable balloon of a balloon catheter; 
         FIG. 9  is a side view of another exemplary system with cutting elements for incising a stenotic lesion; 
         FIG. 9A  is a cross-sectional view of the cutting device of  FIG. 9  taken along line  9 A- 9 A; and 
         FIGS. 10-14  illustrate an exemplary method of treating a stenotic lesion with the incising system of  FIG. 9 . 
     
    
    
     While the aspects of the disclosure are amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit aspects of the disclosure to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure. 
     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. 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 be indicative as including 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). 
     Although some suitable dimensions, ranges and/or values pertaining to various components, features and/or specifications are disclosed, one of skill in the art, incited by the present disclosure, would understand desired dimensions, ranges and/or values may deviate from those expressly disclosed. 
     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 disclosure. 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 side view of an exemplary medical device assembly  10  for incising a stenosis in a blood vessel, or other lesion in an anatomical passage. The medical device assembly  10  may include an incising device  12  including one or more, or a plurality of cutting elements  20  for incising or scoring a stenosis within a blood vessel.  FIG. 1A  is a cross-sectional view taken along line  1 A- 1 A of  FIG. 1 , further illustrating various features of the incising device  12 . The medical device assembly  10  may also include a tubular sheath  34  for delivering the incising device  12  to the stenotic lesion in the blood vessel and/or withdrawing the incising device  12  from the blood vessel in a radially contracted configuration. 
     The incising device  12  may include an expandable scaffold  14  carrying the one or more, or plurality of cutting elements  20  thereon. In some instances, the expandable scaffold  14  may be a self-expanding scaffold  14  configured to automatically radially expand from a first, contracted configuration when radially constrained to a second, radially expanded configuration when unconstrained. Thus, the self-expanding scaffold  14  may be biased to the radially expanded configuration such that the self-expanding scaffold  14  tends to automatically return to the expanded configuration when all radially constraining forces are removed. In other instances, the expandable scaffold  14  may be expanded from a first, radially contracted configuration to a second radially expanded configuration through the application of an expansion force exerted by an expandable member, an expandable linkage, or other actuatable structure for expanding the scaffold  14 . 
     The expandable scaffold  14  may be formed from any number of biocompatible materials, including polymeric materials, metals, and metal alloys, such as stainless steel, tantalum, or a nickel titanium alloy such as a superelastic nickel titanium alloy known as Nitinol, which may have shape memory properties in some instances. 
     The expandable scaffold  14  may have any desired construction permitting the expandable scaffold  14  to be radially compressed into the contracted configuration for positioning in the lumen  38  of the sheath  34 , yet permitting the expandable scaffold  14  to radially expand to the expanded configuration when unconstrained by the sheath  34 . In some instances, the expandable scaffold  14  may be formed of a plurality of interconnected struts, filaments, wires or other expandable framework. For example, as shown in  FIG. 1 , the expandable scaffold  14  may include a plurality of filaments or wires  16  helically wound into a generally tubular construct. A first subset of the wires  16  may be helically wound in a first direction, while a second subset of the wires  16  may be helically wound in a second, opposite direction. The wires  16  may intersect or cross one another at cross-over points  18 . In some instances, the wires  16  may be secured or attached to one another at the cross-over points  18 , or the wires  16  may be unsecured and free to move relative to one another at the cross-over points  18 . 
     The proximal end of the expandable scaffold  14  may include a proximal opening  28  opening into the interior of the expandable scaffold  14 , allowing access to the interior of the expandable scaffold  14  to permit introducing and positioning a balloon of a balloon catheter therein. In some instances, the expandable scaffold  14  may include an annular hoop at the proximal end to define the proximal opening  28  into the interior of the expandable scaffold  14 . The annular hoop may be formed with one or more of the wires  16 , or from a discrete member to which the wires  16  may be attached to. In other instances, the proximal opening  28  may be defined by the collective circumferential arrangement of the proximal ends of the wires  16 . 
     The proximal portion of the expandable scaffold  14  may taper radially inward in a proximal direction to facilitate advancing the sheath  34  back over the expandable scaffold  14  to radially contract the expandable scaffold  14  after use of the incising device  12 . For instance, the proximal end of the expandable scaffold  14  may have a diameter less than the inner diameter of the sheath  34  such that the sheath  34  may surround the proximal tapered portion as the expandable scaffold  14  is drawn into the lumen  38  of the sheath  34 . In some instances, the expandable scaffold  14  may include one or more proximally extending struts  22  to guide the sheath  34  over the expandable scaffold  14  when collapsing the expandable scaffold  14  in the sheath  34  subsequent to using the incising device  12 . 
     The distal end of the helically arranged wires  16  forming the expandable scaffold  14  may converge in a distal direction to a distal tip  24 . As shown in  FIG. 1A , the wires  16  may extend through an arcuate pathway as the wires taper toward the distal tip  24  from the cylindrical portion of the expandable scaffold  14 . In some instances, the distal tip  24  may be constructed of one or more of the wires  16 , such as one or more of the wires  16  tightly wound into a coil. In other embodiments, the distal tip  24  may be formed of a discrete tubular member to which the distal ends of the wires  16  may be secured to. The distal tip  24  may be a tubular construction having a lumen  26  extending therethrough for the passage of a guidewire  30 . Thus, a guidewire  30  may be disposed in the lumen  26  of the distal tip  24 , such that the expandable scaffold  14  of the incising device  12  may be advanced over the guidewire  30  to a treatment site. In some instances, the distal tip  24 , and thus the guidewire  30  extending through the central lumen  26  of the distal tip  24 , may be arranged coaxially with the expandable scaffold  14 , such that a balloon of a balloon catheter advanced over the guidewire  30  into the interior of the expandable scaffold  14  is coaxially positioned within the expandable scaffold  14 . 
     The cutting elements  20  may vary in number, position, and arrangement about the expandable scaffold  14 . For example, the incising device  12  may include one, two, three, four, five, six, or more cutting elements  20  that are disposed at any position along the expandable scaffold  14  and in a regular, irregular, or any other suitable pattern. For example, in some embodiments the incising device  12  may include a plurality of cutting elements  20  longitudinally arranged symmetrically around the circumference of the expandable scaffold  14 . 
     In some instances, the cutting elements  20  may include multiple cutting segments with flexible regions  19  between adjacent segments to increase the flexibility of the cutting elements  20 . In some instances, adjacent segments of the cutting elements  20  may be interconnected with a flexible link, while in other instances adjacent segments of the cutting elements  20  may be spaced from one another at the flexible regions  19 . 
     In some instances, such as shown in  FIG. 1B , the incising device  12  may include a plurality of cutting elements  20  off-set from one another around the circumference of the expandable scaffold  14 . For example, the incising device  12  may include one or more, or a plurality of cutting elements  20  radially offset from, as well as longitudinally offset from one or more, or a plurality of adjacent cutting elements  20 . Thus, the cutting elements  20  may be staggered both radially and longitudinally around the circumference of the expandable scaffold  14 . 
     The cutting elements  20  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, cutting elements  20  may be made from stainless steel, titanium, nickel-titanium alloys, tantalum, iron-cobalt-nickel alloys, or other metallic materials in some instances. 
     As shown in  FIG. 1 , the cutting elements  20  may be mounted to and project radially outward from the expandable scaffold  14 . In other embodiments, the wires  16  of the expandable scaffold  14  may define the cutting elements  20  for scoring or cutting tissue. The cutting elements  20  may be secured to the wires  16  of the expandable scaffold  14  such as by welding, brazing, soldering, crimping, adhesively bonding, thermal bonding, or other desired means. In some instances, the cutting elements  20  may be secured to the expandable scaffold  14  at one or more of the cross-over points  18  of the wires  16 . In some embodiments, it may be desirable to secure the opposing ends of the cutting elements  20  to wires  16  of the expandable scaffold  14 , such as at cross-over points  18  of the wires  16 . 
     The cutting elements  20  may be secured to the generally cylindrical portion of the expandable scaffold  14 , such that the cutting elements  20  may extend in a generally longitudinal direction parallel to the central longitudinal axis of the expandable scaffold  14 . In other instances, the cutting elements  20  may be helically arranged around the circumference of the expandable scaffold  14 , or arranged in another desired configuration. The cutting elements  20  may extend any desired extent of the expandable scaffold  14 . For example, the cutting elements  20  may be secured intermediate the proximal and distal extents of the generally cylindrical portion of the expandable scaffold  14 . 
     As described later herein, a balloon  52 , or other radially expandable member of a catheter  50  may be positioned in the interior of the expandable scaffold  14  to provide a radially outward force to urge the cutting elements  20  radially outward and press the cutting elements  20  against a stenosis or other tissue. In some instances, a balloon of a catheter may be integrally incorporated with the incising device  12 , and thus pre-inserted within the expandable scaffold  14  of the incising device  12  prior to using the incising device  12  in a medical procedure. In other instances, however, the incising device  12  may be provided without a balloon  52  pre-inserted within the expandable scaffold  14 , thus allowing a physician to select any desired balloon  52  or other radially expandable member of a catheter  50  to be inserted within the expandable scaffold  14  intra-operatively, and/or allow for exchanging between a plurality of different sizes of balloons  52  intra-operatively. 
     The incising device  12  may also include an elongate member  32  extending proximally from the expandable scaffold  14  to be manipulated by a physician during a medical procedure. The elongate member  32  may have sufficient rigidity to be pushed distally (e.g., apply an axially compressive force) and pulled proximally (e.g., apply an axially tensile force) to manipulate the expandable scaffold  14 . The elongate member  32 , which may be a tubular member or a solid member in some instances, may have a length sufficient to extend from the treatment site to a handle assembly (not shown) of the medical device assembly  10  located external of the patient such that medical personnel can actuate the elongate member  32  to manipulate the expandable scaffold  14 . For example, the elongate member  32  may extend through the lumen  38  of the tubular sheath  34  adjacent to and generally parallel to the guidewire  30  to a handle assembly of the sheath  34 . The elongate member  32  may be non-coaxially connected to the expandable scaffold  14 , such as attached to the expandable scaffold  14  at a peripheral location offset from the central longitudinal axis of the expandable scaffold  14 , and thus offset from the guidewire  30 . In some instances, one or more struts  22  may extend from the expandable scaffold  14  to the elongate member  32 . 
     The sheath  34  may be a tubular member having a lumen  38  extending therethrough opening out at a distal opening  36  of the tubular sheath  34 . The lumen  38  of the sheath  34  may have an inner diameter sized to receive the expandable scaffold  14  therein in the radially contracted configuration. The expandable scaffold  14  may be positioned in the lumen  38  of the tubular sheath  34  in the contracted configuration with the cutting elements  20  engaged with an interior surface of the tubular sheath  34 . The elongate member  32  may extend proximally through the lumen  38  to the proximal end of the sheath  34 . Likewise, the guidewire  30  may extend through the lumen  38  of the sheath  34  along an exterior surface of the elongate member  32 . 
     While the sheath  34  may be formed of a flexible polymeric tubing for navigating a vasculature, the sheath  34  may include a protective distal tip  40  configured to withstand scoring from the cutting elements  20  as the incising device  12  is advanced out of the lumen  38  through the distal opening  36  and/or withdrawn into the lumen  38  through the distal opening  36 . For instance, the protective distal tip  40  may include a metal annular band, a tubular braid member, a helical coil, or other reinforcing structure providing the protective distal tip  40  sufficient rigidity to withstand cutting forces exerted on the protective distal tip  40  from contact with the cutting elements  20 . In other instances, the protective distal tip  40  may include an impact resistant polymer having a hardness or durability sufficient to withstand cutting forces exerted on the protective distal tip  40  from contact with the cutting elements  20 . 
       FIG. 2  is a side view of another exemplary medical device assembly  110  for incising a stenosis in a blood vessel, or other lesion in an anatomical passage. The medical device assembly  110  may include an incising device  112  including one or more, or a plurality of cutting elements  120  for incising or scoring a stenosis within a blood vessel.  FIG. 2A  is a cross-sectional view taken along line  2 A- 2 A of  FIG. 2 , further illustrating various features of the incising device  112 . Similar to the medical device assembly  10  of  FIG. 1 , the medical device assembly  110  may also include a tubular sheath  34  for delivering the incising device  112  to the stenotic lesion in the blood vessel and/or withdrawing the incising device  112  from the blood vessel. 
     The incising device  112  may be similar to the incising devise  12  in many respects. For example, the incising device  112  may include an expandable scaffold  114  carrying the one or more, or plurality of cutting elements  120  thereon, and be configured to radially expand from a first, contracted configuration when radially constrained to a second, radially expanded configuration when unconstrained. In some instances, the expandable scaffold  114  may be a self-expanding scaffold  114  configured to automatically radially expand from the first, contracted configuration when radially constrained to the second, radially expanded configuration when unconstrained. Thus, the self-expanding scaffold  114  may be biased to the radially expanded configuration such that the self-expanding scaffold  114  tends to automatically return to the expanded configuration when all radially constraining forces are removed. In other instances, the expandable scaffold  114  may be expanded from the first, radially contracted configuration to the second radially expanded configuration through the application of an expansion force exerted by an expandable member, an expandable linkage, or other actuatable structure for expanding the scaffold  114 . 
     The expandable scaffold  114  may have any desired construction permitting the expandable scaffold  114  to be radially compressed into the contracted configuration for positioning in the lumen  38  of the sheath  34 , yet permitting the expandable scaffold  114  to radially expand to the expanded configuration when unconstrained by the sheath  34 . For example, as shown in  FIG. 2 , the expandable scaffold  114  may include a plurality of filaments or wires  116  helically wound with a first wire  116  helically wound in a first direction and a second wire  116  helically wound in a second, opposite direction. The wires  116  may intersect or cross one another at cross-over points  118 . In some instances, the wires  116  may be secured or attached to one another at the cross-over points  118 , or the wires  116  may be unsecured and free to move relative to one another at the cross-over points  118 . The incising device  112  may also include an elongate member  132  extending proximally from the expandable scaffold  114  through the lumen  38  of the sheath  34  to be manipulated by a physician during a medical procedure. In some instances, the elongate member  132  may be formed as a proximal extension of one or more of the wires  116  or as a discrete member secured to the proximal ends of the wires  116 , for example. 
     The expandable scaffold  114  may include a proximal opening  128  opening into the interior of the expandable scaffold  114 , allowing access to the interior of the expandable scaffold  114  to permit introducing and positioning a balloon of a balloon catheter therein. In some instances, the proximal opening  128  may be defined by the proximal most arcuate winding of the wires  116  from the elongate member  132  to the first proximal most cross-over point  118  of the wires  116 . 
     The distal end of the helically arranged wires  116  forming the expandable scaffold  114  may terminate at a distal tip  124 . As shown in  FIG. 2A , the wires  116  may extend through an arcuate pathway of a smaller radius of curvature as the wires taper toward the distal tip  124  from the cylindrical portion of the expandable scaffold  114 . Similar to the distal tip  24 , the distal tip  124  may be constructed of one or more of the wires  116 , or the distal tip  124  may be formed of a discrete tubular member to which the distal ends of the wires  116  may be secured to, having a lumen  126  extending therethrough for the passage of a guidewire  30 . In some instances, the distal tip  124 , and thus the guidewire  30  extending through the central lumen  126  of the distal tip  124 , may be arranged coaxially with the expandable scaffold  114 , such that a balloon of a balloon catheter advanced over the guidewire  30  into the interior of the expandable scaffold  114  is coaxially positioned within the expandable scaffold  114 . 
     The cutting elements  120  may vary in number, position, and arrangement about the expandable scaffold  114 . For example, the incising device  112  may include one, two, three, four, five, six, or more cutting elements  120  that are disposed at any position along the expandable scaffold  114  and in a regular, irregular, or any other suitable pattern. For example, in some embodiments the incising device  112  may include a plurality of cutting elements  120  longitudinally arranged symmetrically around the circumference of the expandable scaffold  114 . 
     As shown in  FIG. 2 , the cutting elements  120  may be mounted to and project radially outward from the expandable scaffold  114 . In other embodiments, the wires  116  of the expandable scaffold  114  may define the cutting elements  120  for scoring or cutting tissue. 
     As shown in  FIG. 2 , in some instances, the cutting elements  120  may be mounted to the expandable scaffold  114  such that the wires  116  may be translatable relative to the cutting elements  120 . For example, the cutting elements  120  may include grommets or collars  122  through which the wires  116  slidably extend through, allowing the cutting elements  120  to float on the wires  116 . In such instances, the expandable scaffold  114  may be collapsed by longitudinally extending the wires  116  such that the connection between the cutting elements  120  and the wires  116  at the collars  122  translates along the wires  116  as the wires  116  are elongated. In some instances, the cutting elements  120  may be configured such that a cutting edge of the cutting element  120  is oriented radially outward to contact a vessel wall or stenosis regardless of the rotational orientation of the cutting element  120  about its longitudinal axis. 
     In other instances, the cutting elements  120  may be secured to the wires  116  of the expandable scaffold  114  such as by welding, brazing, soldering, crimping, adhesively bonding, thermal bonding, or other desired means. In some instances, the cutting elements  120  may be secured to the cylindrical portion of the expandable scaffold  114  at one or more of the cross-over points  118  of the wires  116 . In some embodiments, it may be desirable to secure the opposing ends of the cutting elements  120  to wires  116  of the expandable scaffold  114 , such as at cross-over points  118  of the wires  116 . For example, a first cutting element  120  may have a proximal end secured to the wires  116  at the proximal terminus of the expandable scaffold  114  and a distal end secured to the wires  116  at a cross-over point  118  distal of the proximal terminus of the expandable scaffold  114 . A second cutting element  120 , which may be secured to the expandable scaffold  114  on an opposite side of the expandable scaffold as the first cutting element  120 , may have a proximal end secured to a proximal cross-over point  118  and a distal end secured to a distal cross-over point  118 . The first cutting element  120  may be offset longitudinally from the first cutting element  120  as the securement locations (e.g., cross-over points  118 ) on opposite sides of the expandable scaffold  114  may be alternately arranged axially along the expandable scaffold  114 . 
     As described later herein, a balloon  52 , or other radially expandable member of a catheter  50  may be positioned in the interior of the expandable scaffold  114  to provide a radially outward force to urge the cutting elements  120  radially outward and press the cutting elements  120  against a stenosis or other tissue. In some instances, a balloon of a catheter may be integrally incorporated with the incising device  112 , and thus pre-inserted within the expandable scaffold  114  of the incising device  112  prior to using the incising device  112  in a medical procedure. In other instances, however, the incising device  112  may be provided without a balloon  52  pre-inserted within the expandable scaffold  114 , thus allowing a physician to select any desired balloon  52  or other radially expandable member of a catheter  50  to be inserted within the expandable scaffold  114  intra-operatively, and/or allow for exchanging between a plurality of different sizes of balloons  52  intra-operatively. 
       FIG. 3  is a side view of another exemplary medical device assembly  210  for incising a stenosis in a blood vessel, or other lesion in an anatomical passage. The medical device assembly  210  may include an incising device  212  including one or more, or a plurality of cutting elements  220  for incising or scoring a stenosis within a blood vessel.  FIG. 3A  is a cross-sectional view taken along line  3 A- 3 A of  FIG. 3 , further illustrating various features of the incising device  212 . Similar to the medical device assembly  10  of  FIG. 1 , the medical device assembly  210  may also include a tubular sheath  34  for delivering the incising device  212  to the stenotic lesion in the blood vessel and/or withdrawing the incising device  212  from the blood vessel. 
     The incising device  212  may be similar to the incising devise  12  in many respects. For example, the incising device  212  may include an expandable scaffold  214  carrying the one or more, or plurality of cutting elements  220  thereon, and be configured to radially expand from a first, contracted configuration when radially constrained to a second, radially expanded configuration when unconstrained. In some instances, the expandable scaffold  214  may be a self-expanding scaffold  214  configured to automatically radially expand from the first, contracted configuration when radially constrained to the second, radially expanded configuration when unconstrained. Thus, the self-expanding scaffold  214  may be biased to the radially expanded configuration such that the self-expanding scaffold  214  tends to automatically return to the expanded configuration when all radially constraining forces are removed. In other instances, the expandable scaffold  214  may be expanded from the first, radially contracted configuration to the second radially expanded configuration through the application of an expansion force exerted by an expandable member, an expandable linkage, or other actuatable structure for expanding the scaffold  214 . 
     The expandable scaffold  214  may have any desired construction permitting the expandable scaffold  214  to be radially compressed into the contracted configuration for positioning in the lumen  38  of the sheath  34 , yet permitting the expandable scaffold  214  to radially expand to the expanded configuration when unconstrained by the sheath  34 . For example, as shown in  FIG. 3 , the expandable scaffold  214  may include a plurality of struts  216  extending longitudinally along the expandable scaffold  214 . The struts  216 , which may be wires or other filaments in some instances, may be circumferentially arranged uniformly or nonuniformly around the circumference of the expandable scaffold  214 . The incising device  212  may also include an elongate member  232  extending proximally from the expandable scaffold  214  through the lumen  38  of the sheath  34  to be manipulated by a physician during a medical procedure. In some instances, the elongate member  232  may be formed as a proximal extension of one or more of the struts  216  or as a discrete member secured to the expandable scaffold  214 , for example. A one or more, or a plurality of additional extension wires  222  may extend from the expandable scaffold  214  to the elongate member  232 , providing a tapered transition from the elongate member  232  to struts  216  of the expandable scaffold  214  to facilitate drawing the expandable scaffold  214  into the sheath  34 . In some instances, the proximally extending extension wires  222  may be unitarily formed from the struts  216 , or the extension wires  222  may be discrete members extending between the elongate member  232  and the struts  216 . The circumferentially arranged extension wires  222  may define a proximal opening  228  opening into the interior of the expandable scaffold  214 , allowing access to the interior of the expandable scaffold  214  to permit introducing and positioning a balloon of a balloon catheter therein. The proximal tapered portion provided by the extension wires  222  may facilitate positioning the sheath  34  back over the expandable scaffold  214  to radially contract the expandable scaffold  214  after use of the incising device  212 . For instance, the one or more proximally extending extension wires  222  may help guide the sheath  34  over the expandable scaffold  214  when collapsing the expandable scaffold  214  in the sheath  34  subsequent to using the incising device  212 . 
     The longitudinal struts  216  may extend axially to define a cylindrical portion of the expandable scaffold  214 , and then taper radially inward near the distal end of the expandable scaffold  214  to converge at a distal tip  224 . The distal tip  224  may be a tubular member having a lumen  226  extending therethrough for the passage of a guidewire  30 . In some instances such as shown in  FIG. 3A , the distal tip  224 , and thus the guidewire  30  extending through the central lumen  226  of the distal tip  224 , may be arranged coaxially with the expandable scaffold  214 , such that a balloon of a balloon catheter advanced over the guidewire  30  into the interior of the expandable scaffold  214  is coaxially positioned within the expandable scaffold  214 . 
     The cutting elements  220  may vary in number, position, and arrangement about the expandable scaffold  214 . For example, the incising device  212  may include one, two, three, four, five, six, or more cutting elements  220  that are disposed at any position along the expandable scaffold  214  and in a regular, irregular, or any other suitable pattern. For example, in some embodiments the incising device  212  may include a plurality of cutting elements  220  longitudinally arranged symmetrically around the circumference of the expandable scaffold  214 . 
     As shown in  FIG. 3 , the cutting elements  220  may be mounted to and project radially outward from the struts  216  of the expandable scaffold  214 . In other embodiments, the struts  216  of the expandable scaffold  214  may define the cutting elements  220  for scoring or cutting tissue. The cutting elements  220  may be secured to the struts  216  of the expandable scaffold  214  such as by welding, brazing, soldering, crimping, adhesively bonding, thermal bonding, or other desired means. 
     As described later herein, a balloon  52 , or other radially expandable member of a catheter  50  may be positioned in the interior of the expandable scaffold  214  to provide a radially outward force to urge the cutting elements  220  radially outward and press the cutting elements  220  against a stenosis or other tissue. In some instances, a balloon of a catheter may be integrally incorporated with the incising device  212 , and thus pre-inserted within the expandable scaffold  214  of the incising device  212  prior to using the incising device  212  in a medical procedure. In other instances, however, the incising device  212  may be provided without a balloon  52  pre-inserted within the expandable scaffold  214 , thus allowing a physician to select any desired balloon  52  or other radially expandable member of a catheter  50  to be inserted within the expandable scaffold  214  intra-operatively, and/or allow for exchanging between a plurality of different sizes of balloons  52  intra-operatively. 
       FIGS. 4-8  illustrate an exemplary method of treating a stenotic lesion with an expandable scaffold with cutting elements in cooperation with an inflatable balloon of a balloon catheter. Although the exemplary method will be described in regards to using the incising device  12 , it is understood that such a method of treating a stenosis may be performed using the incising device  112  described in  FIG. 2 , the incising device  212  described in  FIG. 3 , or a similarly configured incising device in accordance with this disclosure. 
     The medical device assembly  10  may be navigated through the lumen  92  of a blood vessel  90  to a treatment location proximate a stenosis  94  or other tissue to be treated which may be within any suitable peripheral or cardiac vessel lumen location. For instance, the incising device  12  may be loaded in the sheath  34  with the expandable scaffold  14  constrained in the contracted position within the lumen  38  of the sheath  34  prior to advancing the medical device assembly  10  through the blood vessel  90 . Alternatively, the sheath  34  may be initially placed proximate the stenosis  94 , and subsequently the incising device  12  may be inserted into the lumen  38  and pushed distally through the sheath  34  to the treatment site. 
     The distal tip  24  of the incising device  12  may be inserted over a guidewire  30 , with the guidewire  30  extending through the interior of the expandable scaffold  14  and through the lumen  38  of the sheath  34 . As shown in  FIG. 4 , the expandable scaffold  14  of the incising device  12  may be advanced in the contracted configuration over the guidewire  30  while constrained within the lumen  38  of the tubular sheath  34  to the stenosis  94  in the blood vessel  90 . The guidewire  30  may extend along and adjacent to the elongate member  32  of the incising device  12  within the lumen  38  of the sheath  34 . 
     As shown in  FIG. 5 , with the radially constrained expandable scaffold  14  positioned across the stenosis  94  within the sheath  34 , the sheath  34  may be withdrawn proximally to deploy the expandable scaffold  14  distally from the distal opening  36  of the tubular sheath  34 . For example, the physician may hold the elongate member  32  of the incising device  12  while pulling the sheath  34  proximally to maintain the expandable scaffold  14  in a desired position as the sheath  34  is withdrawn. Alternatively, the physician may push the elongate member  32  distally while holding the sheath  34  to expel the expandable scaffold  14  from the distal opening  36  of the sheath  34 . The protective distal tip  40  of the sheath  34  may withstand scoring from the cutting elements  20  as the incising device  12  is advanced out of the lumen  38  through the distal opening  36 . Once unconstrained by the sheath  34 , the expandable scaffold  14  may automatically radially expand toward the expanded configuration. The expandable scaffold  14  may be sized such that in the expanded configuration, the cutting elements  20  may contact and/or press against the stenosis  94 . 
     As shown in  FIG. 6 , a deflated balloon  52 , or other expandable member, of a catheter  50  (if not already disposed in the interior of the expandable scaffold  14  prior to deploying the incising device  12  across the stenosis  94 ) may be advanced distally over the guidewire  30  through the proximal opening  28  into the interior of the expandable scaffold  14  with the expandable scaffold  14  in the expanded configuration. The catheter  50  may be selected by the physician based on the desired inflated diameter of the balloon  52  for a particular medical procedure. For example, the balloon  52  chosen may be selected based on the diameter of the vessel to be treated, the size of the stenosis, and/or the amount of radial expansion of the expandable scaffold  14  desired. In some instances, the catheter  50  may be advanced over the guidewire  30  through the lumen  38  of the sheath  34 , or the sheath  34  may be completely withdrawn from the patient prior to advancing the catheter  50  over the guidewire  30 . 
     In some instances, the balloon  52  may be formed of a compliant material, a semi-compliant material, or a non-compliant material. The balloon  52  may be made from typical angioplasty balloon materials including polymers such as polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), polybutylene terephthalate (PBT), polyurethane, polyvinylchloride (PVC), polyether-ester, polyester, polyamide, elastomeric polyamides, polyether block amide (PEBA), as well as other suitable materials, or mixtures, combinations, copolymers thereof, polymer/metal composites, and the like. The balloon  52  may be configured so that the balloon  52  includes one or more “wings” or wing-shaped regions when the balloon  52  is deflated. 
     The catheter  50  may include a catheter shaft  54  secured to the balloon  52  and extending proximally therefrom. The catheter shaft  54  may be similar to typical catheter shafts. For example, the catheter shaft  54  may include an outer tubular member and an inner tubular member extending through at least a portion of the outer tubular member. The tubular members may be arranged in any appropriate way. For example, in some embodiments the inner tubular member can be disposed coaxially within the outer tubular member. Alternatively, the inner tubular member may follow the inner wall or otherwise be disposed adjacent the inner wall of the outer tubular member. In other embodiments, the tubular members may be arranged in another desired fashion. 
     The inner tubular member may include an inner lumen, such as a guidewire lumen for receiving the guidewire  30  therethrough. Accordingly, the catheter  50  can be advanced over the guidewire  30  to the desired location. The guidewire lumen may extend along essentially the entire length of the catheter shaft  54  such that catheter  50  resembles traditional “over-the-wire” catheters. Alternatively, the guidewire lumen may extend along only a portion of the catheter shaft  54  such that the catheter  50  resembles “single-operator-exchange” or “rapid-exchange” catheters. 
     The catheter shaft  54  may also include an inflation lumen that may be used, for example, to transport inflation media to and from the balloon  52  to selectively inflate and/or deflate the balloon  52 . The location and position of the inflation lumen may vary, depending on the configuration of the tubular members of the catheter shaft  54 . For example, when the outer tubular member surrounds the inner tubular member, the inflation lumen may be defined within the space between the tubular members. In embodiments in which the outer tubular member is disposed alongside the inner tubular member, then the inflation lumen may be the lumen of the outer tubular member. 
     The balloon  52  may be coupled to the catheter shaft  54  in any of a number of suitable ways. For example, the balloon  52  may be adhesively or thermally bonded to the catheter shaft  54 . In some embodiments, a proximal waist of the balloon  52  may be bonded to the catheter shaft  54 , for example, bonded to the distal end of the outer tubular member, and a distal waist of the balloon  52  may be bonded to the catheter shaft  54 , for example, bonded to the distal end of the inner tubular member. The exact bonding positions, however, may vary. 
     In some instances, the catheter  50  may be properly positioned within the interior of the expandable scaffold  14  when the distal tip  56  of the catheter  50  contacts a proximal end of the distal tip  24  of the incising device  12 . As the balloon  52  and catheter  50  may be advanced over the guidewire  30 , which extends centrally through the expandable scaffold  14 , the balloon  52  may likewise be concentrically positioned within the interior of the expandable scaffold  14 . 
     As shown in  FIG. 7 , once positioned within the interior of the expandable scaffold  14 , the balloon  52  can be inflated to exert a radially outward force on the interior of the expandable scaffold  14  to further enlarge the expandable scaffold  14  and/or to urge the cutting elements  20  further radially outward to penetrate into or score the stenosis  94 . Thus, the cutting elements  20  may cut or score the stenosis  94  to facilitate enlarging the lumen proximate the stenosis  94 . 
     Subsequently, the balloon  52  may be deflated and withdrawn proximally from the interior of the expandable scaffold  14  through the proximal opening  28  of the expandable scaffold  14  with the expandable scaffold  14  in the expanded configuration. In some instances, it may be desirable to advance a second balloon of a second balloon catheter over the guidewire  30  into the interior of the expandable scaffold  14  through the proximal opening  28  of the expandable scaffold  14  with the expandable scaffold  14  in the expanded configuration. For example, the first balloon  52  of the first catheter  50  may have a first inflated diameter and the second balloon  52  of the second catheter  50  may have a second inflated diameter greater than the inflated diameter of the first balloon  52 . Thus, the first balloon  52  may be used to radially expand the expandable scaffold to a first diameter and urge the cutting elements  20  into the stenosis  94  a first amount, and then the first balloon  52  and catheter  50  may be exchanged for the second balloon  52  and catheter  50  to further expand the expandable scaffold to a second diameter greater than the first diameter and urge the cutting elements further into the stenosis  94  a second amount, greater than the first amount. The balloons  52  may be sequentially exchanged for balloons  52  of a different size (e.g., of a sequentially greater size), as desired until a desired dilatation of the blood vessel  90  has been attained. 
     As shown in  FIG. 8 , once the desired treatment of the blood vessel  90  with the incising device  12  has been achieved, the incising device  12  may be recaptured and retrieved with the sheath  34 , and then withdrawn from the blood vessel  90 . For example, as shown in  FIG. 8 , the sheath  34 , or another sheath, may be advanced distally to the expandable scaffold  14 . The physician may grasp the elongate member  32  to hold the expandable scaffold  14  stationary while advancing the sheath  34  distally over the expandable scaffold  14  to collapse the expandable scaffold  14  into the lumen  38  of the sheath  34 , or the physician may pull the elongate member  32  proximally to pull the self-expanding scaffold  14  into the distal opening  36  of the sheath  34  to collapse the expandable scaffold  14  into the lumen  38  of the sheath  34 . The protective distal tip  40  of the sheath  34  may withstand scoring from the cutting elements  20  as the incising device  12  is retracted into the lumen  38  through the distal opening  36 . The sheath  34  and incising device  12  may then be withdrawn from the blood vessel  90 , leaving the guidewire  30  in place for navigating additional medical devices across the stenosis  94  in the blood vessel  90 , if desired. 
       FIG. 9  is a side view of another exemplary medical device assembly  310  for incising a stenosis in a blood vessel, or other lesion in an anatomical passage. The medical device assembly  310  may include an incising device  312  including one or more, or a plurality of cutting elements  320  for incising or scoring a stenosis within a blood vessel. Similar to the medical device assembly  10  of  FIG. 1 , the medical device assembly  310  may also include a tubular sheath  34  for delivering the incising device  312  to the stenotic lesion in the blood vessel and/or withdrawing the incising device  312  from the blood vessel. 
     The incising device  312  may be similar to the incising devise  12  in many respects. For example, the incising device  312  may include an expandable scaffold  314  carrying the one or more, or plurality of cutting elements  320  thereon, and be configured to radially expand from a first, contracted configuration when radially constrained to a second, radially expanded configuration when unconstrained. In some instances, the expandable scaffold  314  may be a self-expanding scaffold  314  configured to automatically radially expand from the first, contracted configuration when radially constrained to the second, radially expanded configuration when unconstrained. Thus, the self-expanding scaffold  314  may be biased to the radially expanded configuration such that the self-expanding scaffold  314  tends to automatically return to the expanded configuration when all radially constraining forces are removed. In other instances, the expandable scaffold  314  may be expanded from the first, radially contracted configuration to the second radially expanded configuration through the application of an expansion force exerted by an expandable member, an expandable linkage, or other actuatable structure for expanding the scaffold  314 . 
     The expandable scaffold  314  may have any desired construction permitting the expandable scaffold  314  to be radially compressed into the contracted configuration for positioning in the lumen  38  of the sheath  34 , yet permitting the expandable scaffold  314  to radially expand to the expanded configuration when unconstrained by the sheath  34 . For example, as shown in  FIG. 9 , the expandable scaffold  314  may be formed of a unitary tubular mesh framework of interconnected struts  316 , similar to the structure of an expandable stent. At least some of the interconnected struts  316  may extend between adjacent cutting elements  320  within the tubular body portion of the expandable scaffold  314  to provide stability between adjacent cutting elements  320 . For instance, at least a portion of the interconnected struts  316  may, at least in part, extend circumferentially around the circumference of the expandable scaffold  314  such that interconnected struts  316  extend between adjacent cutting elements  320  around the tubular body portion. 
     The tubular mesh framework  316  may define a cylindrical body portion of the expandable scaffold  314 . The expandable scaffold  314  may also include one or more, or a plurality of proximally extending extension wires  322  extending from the proximal end of the tubular mesh framework  316  to a proximal tubular collar  360  positionable around a tubular shaft of a balloon catheter  350 . The expandable scaffold  314  may additionally include one or more, or a plurality of distally extending extension wires  323  extending from the distal end of the tubular mesh framework  316  to a distal tubular collar  362  positionable around a tubular shaft of the balloon catheter  350 . 
     The medical device assembly  310  may also include a balloon catheter  350  including an inflatable balloon  352  secured to the catheter shaft  354  of the balloon catheter  350  at a proximal balloon waist  358  and a distal balloon waist  359 . In some instances, the catheter shaft  354  may include an inner tubular member  357  defining a guidewire lumen extending coaxially within an outer tubular member  355 , defining an annular inflation lumen therebetween for inflating the inflatable balloon  352 . A hypotube  353  may extend over a proximal portion of the outer tubular member  355  to provide column support to the proximal portion of the catheter shaft  354 . In other embodiments, the catheter shaft  354  may be provided with another configuration, such as first and second parallel tubular members to define a guidewire lumen and an inflation lumen, respectively. 
     The proximal collar  360  may surround the catheter shaft  354  proximal of the inflatable main portion of the balloon  352 , such as around the outer tubular member  355  of the catheter shaft  354  proximate to and/or proximal of the proximal balloon waist  358 . Similarly, the distal collar  362  may surround the catheter shaft  354  distal of the inflatable main portion of the balloon  352 , such as around the inner tubular member  357  of the catheter shaft  354  proximate to and/or distal of the distal balloon waist  359 . The proximal collar  360  and/or the distal collar  362  may be configured to rotate and/or translate relative to the catheter shaft  354  in some instances. 
     The catheter  350  may also include a distal tip  356 , such as an enlarged distal tip positioned distal of the distal collar  362 , and thus distal of the balloon  352  and the expandable scaffold  314  surrounding the balloon  352 . In some instances, the distal tip  356  may function as a distal stop to prevent the distal collar  362  from being removed from the catheter shaft  354 . The expandable scaffold  314  may be permitted to have a limited amount of longitudinal movement relative to the catheter shaft  354 , as well as rotational movement about the catheter shaft  354 . Movement of the proximal and distal collars  360 ,  362  may facilitate expansion and contraction of the expandable scaffold  314  about the balloon  352 . The distal tip  356  may have a lumen extending therethrough for the passage of a guidewire  30 . In some instances such as shown in  FIG. 3A , the distal tip  356 , and thus the guidewire  30  extending through the central lumen of the distal tip  356 , may be arranged coaxially with the expandable scaffold  314  and the balloon  352  of the balloon catheter  350 , with the balloon  352  coaxially positioned within the expandable scaffold  314 . In some instances, the distal tip  356  may also provide an atraumatic tip to the sheath  34  when the incising device  312  is retracted into the lumen  38  of the sheath  34 . Thus, in some instances, the distal tip  356 , or a portion thereof, may be sized to remain exterior and distal of the sheath  34  when the expandable scaffold  314  of the incising device  312  is positioned within the sheath  34  during delivery and/or retrieval. 
     In some instances, the incising device  312  may also include an elongate member  332  extending proximally from the proximal collar  360  along an exterior of the catheter shaft  354  to be manipulated by a physician during a medical procedure to facilitate expelling the expandable scaffold  314  from the sheath  34 , drawing the expandable scaffold  314  into the sheath  34 , or otherwise manipulating the expandable scaffold  314 . The elongate member  332  and the catheter shaft  354  may extend through the lumen  38  of the sheath  34  to a proximal end of the medical device assembly  310 . 
     In some instances, the proximal tapered portion provided by the extension wires  322  may facilitate positioning the sheath  34  back over the expandable scaffold  314  to radially contract the expandable scaffold  314  after use of the incising device  312 . For instance, the one or more proximally extending extension wires  322  may help guide the sheath  34  over the expandable scaffold  314  when collapsing the expandable scaffold  314  in the sheath  34  subsequent to using the incising device  312 . 
     The cutting elements  320  may vary in number, position, and arrangement about the expandable scaffold  314 . For example, the incising device  312  may include one, two, three, four, five, six, or more cutting elements  320  that are disposed at any position along the expandable scaffold  314  and in a regular, irregular, or any other suitable pattern. For example, in some embodiments the incising device  312  may include a plurality of cutting elements  320  longitudinally arranged symmetrically around the circumference of the expandable scaffold  314 . 
     As shown in  FIG. 9A , the cutting elements  320  may be mounted to and project radially outward from the expandable scaffold  314 . In other embodiments, the struts  316  of the expandable scaffold  314  may define the cutting elements  320  for scoring or cutting tissue. The cutting elements  320  may be secured to the struts  316  of the expandable scaffold  314  such as by welding, brazing, soldering, crimping, adhesively bonding, thermal bonding, or other desired means. 
     The balloon  352  of the balloon catheter  350  may be positioned in the interior of the expandable scaffold  314  to provide a radially outward force to urge the cutting elements  320  radially outward and press the cutting elements  320  against a stenosis or other tissue. For instance, the balloon  352  of the catheter  350  may be integrally incorporated with the incising device  312 , and thus pre-inserted within the expandable scaffold  314  of the incising device  312  prior to using the incising device  312  in a medical procedure. In other instances, however, the incising device  312  may be provided without a balloon  352  pre-inserted within the expandable scaffold  314 , thus allowing a physician to select any desired balloon  352  or other radially expandable member of a catheter  350  to be inserted within the expandable scaffold  314  intra-operatively, and/or allow for exchanging between a plurality of different sizes of balloons  352  intra-operatively. 
     The catheter shaft  354  and sheath  34  may extend proximally to a proximal handle assembly  380  at a proximal end of the medical device assembly  310  to be manipulated by a user. The handle assembly  380  may include a manifold  382  coupled to the proximal end of the catheter shaft  354 . For example, the proximal end of the hypotube  354 , the proximal end of the outer tubular member  355  and/or the proximal end of the inner tubular member  357  may be secured to the manifold  382 , such as with an adhesive, or other bonding method. As shown in  FIG. 9 , the proximal end of the hypotube  353  and the proximal end of the outer tubular member  355  may extend into the manifold  382  with the proximal end of the outer tubular member  355  extending proximal of the proximal end of the hypotube  353 . The proximal end of the inner tubular member  357  may extend proximally beyond the proximal end of the outer tubular member  355 . The manifold  382  may include one or more ports, such as a guidewire port  384  in communication with the guidewire lumen of the inner tubular member  357  from which the guidewire  30  may extend from, and an inflation port  386  in fluid communication with the inflation lumen between the inner tubular member  357  and the outer tubular member  355  in which an inflation media may be delivered to the interior of the balloon  352  through the inflation lumen. 
     The handle assembly  380  may also include an actuation member  388 , such as a push-pull knob or handle, coupled to the proximal end of the sheath  34  for manipulation of the sheath  34  to deploy and/or retrieve the incising device  312 . In other instances, the handle assembly  380  may include an alternative structure configured for actuating the sheath  34 . Some additional structures may include a dial, a thumb push/pull lever, or other structure to effect actuation of the sheath  34  relative to the catheter shaft  354 . A user may manipulate the actuation member  388  to translate the sheath  34  in a proximal direction and/or a distal direction in order to withdraw the sheath  34  from the expandable scaffold  314  and/or advance the sheath  34  over the expandable scaffold  314 , respectively. In some instances, the actuation member  388  may include a locking mechanism to prevent inadvertent relative movement between the sheath  34  and the catheter shaft  354  to prevent premature deployment of the expandable scaffold  314  from the sheath  34 . In some instances, a distal end of the hypotube  353  may be located proximate the actuation member  388  when the sheath  34  has been pulled proximally to withdraw the sheath  34  from the expandable scaffold  314 . 
     The medical device assembly  310 , as well as the medical device assemblies  10 ,  110  and  210 , may also include radiopaque marker bands  375  positioned on or incorporated in various components of the assembly  310  in order to permit visual observation of the assembly  310  in a body vessel under fluoroscopy or other visualization technique. For example, the sheath  34  may include a radiopaque marker band  375  proximate the distal end of the sheath  34 . Furthermore, the catheter shaft  356  may include radiopaque marker bands  375  positioned proximal and distal of the balloon  352  and/or the proximal and distal collars  360 ,  362  may include radiopaque marker bands  375  or be formed of a radiopaque material to facilitate positioning the incising device  312  across a stenosis. Additionally, the distal tip  356  may include a radiopaque marker band  375  or be formed of a radiopaque material in order to visualize the position of the distal tip  356  in a vessel. Additional radiopaque markers may be incorporated into the expandable scaffold  314  or other components of the medical device assembly  310 , as desired. 
       FIGS. 10-14  illustrate an exemplary method of treating a stenotic lesion with the medical device assembly  310  illustrated in  FIG. 9 . Although the exemplary method will be described in regards to using the medical device assembly  310 , it is understood that such a method of treating a stenosis may be performed using any of the assemblies and incising device described herein, or a similarly configured incising device in accordance with this disclosure. 
     The medical device assembly  310  may be navigated through the lumen  92  of a blood vessel  90  to a treatment location proximate a stenosis  94  or other tissue to be treated which may be within any suitable peripheral or cardiac vessel lumen location. For instance, the incising device  312  may be loaded in the sheath  34  with the expandable scaffold  314  constrained in the contracted position within the lumen  38  of the sheath  34  prior to advancing the medical device assembly  10  through the blood vessel  90 . The distal tip  356  may be located at the distal end of the sheath  34 , providing an atraumatic tip for insertion of the medical device assembly  310  through the vasculature. 
     The distal tip  356  may be inserted over a previously positioned guidewire  30 , with the guidewire  30  extending through the interior of the expandable scaffold  314  and through the lumen  38  of the sheath  34 . As shown in  FIG. 10 , sheath  34 , with the expandable scaffold  314  of the incising device  312  positioned therein, may be advanced to the stenosis  94  in the blood vessel  90 . The guidewire  30  may extend through a guidewire lumen of the catheter shaft  354  of the catheter  350 , which extends within the lumen  38  of the sheath  34 . The sheath  34  may be advanced across the stenosis  94  until the expandable scaffold  314  is properly positioned. Radiopaque marker bands  275  incorporated with the components of the medical device assembly  310  may be used to visually confirm the position of the expandable scaffold  314  across the stenosis  94  using fluoroscopy or other visualization technique. 
     As shown in  FIG. 11 , once the radially constrained expandable scaffold  314  is positioned across the stenosis  94  within the sheath  34 , the sheath  34  may be withdrawn proximally to deploy the expandable scaffold  314  distally from the distal opening  36  of the tubular sheath  34 . For example, the physician may pull the actuation member  388 , or otherwise actuate the actuation member  388 , to withdraw the sheath  34  proximally to deploy the expandable scaffold  314  from the distal end of the sheath  34 . Radiopaque marker bands  275  incorporated with the components of the medical device assembly  310  may be used to visually confirm the position of the distal end of the sheath  34  relative to the expandable scaffold  314  to ensure of proper deployment of the expandable scaffold  314  using fluoroscopy or other visualization technique. 
     The protective distal tip  40  of the sheath  34  may withstand scoring from the cutting elements  320  as the incising device  312  is advanced out of the lumen  38  through the distal opening  36 . Once unconstrained by the sheath  34 , the expandable scaffold  314 , in instances in which the scaffold  314  is self-expandable, may automatically radially expand toward the expanded configuration. The expandable scaffold  314  may be sized such that in the expanded configuration, the cutting elements  320  may contact and/or press against the stenosis  94 . 
     As shown in  FIG. 12 , the deflated balloon  352  of the catheter  350 , positioned within the expandable scaffold  314  can be inflated to exert a radially outward force on the interior of the expandable scaffold  314  to further enlarge the expandable scaffold  314  and/or to urge the cutting elements  320  further radially outward to penetrate into or score the stenosis  94 . Thus, the cutting elements  320  may cut or score the stenosis  94  to facilitate enlarging the lumen proximate the stenosis  94 . Subsequently, the balloon  352  may be deflated within the interior of the expandable scaffold  314 . 
     As shown in  FIG. 13 , once the desired treatment of the blood vessel  90  with the incising device  312  has been achieved, the incising device  312  may be recaptured and retrieved with the sheath  34 , and then withdrawn from the blood vessel  90 . For example, as shown in  FIG. 13 , the sheath  34 , or another sheath, may be advanced distally to the expandable scaffold  314 . For example, the actuation member  388  may be actuated distally relative to the elongate shaft  354 , or otherwise actuated, to advance the sheath  34  distally over the expandable scaffold  314  and thus collapse the expandable scaffold  314  into the lumen  38  of the sheath  34 . The protective distal tip  40  of the sheath  34  may withstand scoring from the cutting elements  320  as the incising device  312  is retracted into the lumen  38  through the distal opening  36 . 
     As shown in  FIG. 14 , the sheath  34  may be advanced distally until the expandable scaffold  314  is within the sheath  34  and the distal tip  356  is located at the distal end of the sheath  34 . Radiopaque marker bands  275  may be used to visually confirm the position of the expandable scaffold  314  within the lumen  38  of the sheath  34  and/or the distal tip  356  at the distal end of the sheath  34  using fluoroscopy or other visualization technique. The sheath  34  and incising device  312  may then be withdrawn from the blood vessel  90 , leaving the guidewire  30  in place for navigating additional medical devices across the stenosis  94  in the blood vessel  90 , if desired. 
     The above described features of expandable scaffolds including cutting elements may permit the cutting elements to be delivered to a stenotic lesion in a blood vessel without being directed mounted to an angioplasty balloon. The scaffolding, with the cutting members secured thereto, may be more flexible for navigating tortuous anatomy, while securely delivering the cutting elements to the treatment site. 
     Those skilled in the art will recognize that the present disclosure may be manifested in a variety of forms other than the specific embodiments described and contemplated herein. Accordingly, departure in form and detail may be made without departing from the scope and spirit of the present disclosure as described in the appended claims.