Patent Publication Number: US-7717930-B2

Title: Valvulotome with a cutting edge

Description:
This application claims the benefit of U.S. Provisional Application No. 60/548,246, filed Feb. 27, 2004, and U.S. Provisional Application No. 60/581,852, filed Jun. 21, 2004, both of which are incorporated by reference in their entirety. 
    
    
     FIELD 
     The present invention relates to devices for removing or disabling valves within body vessels, such as venous valves. More particularly, the invention pertains to particular valvulotome devices and methods for using the same. 
     BACKGROUND 
     In mammalian veins, venous valves are positioned within portions of the vessel in the form of leaflets disposed annularly along the inside wall of the vein which open to permit blood flow toward the heart and close to prevent back flow. These venous valves open to permit the flow of fluid in the desired direction, and close upon a change in pressure, such as a transition from systole to diastole. When blood flows through the vein, the pressure forces the valve leaflets apart as they flex in the direction of blood flow and move toward the inside wall of the vessel, creating an opening in between for blood flow. The leaflets, however, do not normally bend in the opposite direction and therefore return to a closed position to restrict or prevent blood flow in the opposite, i.e. retrograde, direction after the pressure is relieved. The leaflets, when functioning properly, extend radially inwardly toward one another such that the tips contact each other to block backflow of blood. The competence of venous valves can be degraded or reduced if the leaflets do not adequately contact each other. 
     Disabling of incompetent venous valves can be performed for various reasons. For example, disabling of incompetent venous valves can be performed prior to implantation of a venous valve prosthesis. Venous valves may also be disabled within a section of vein used as a graft for surgical implantation at another site, where venous valves are often removed or disabled prior to implantation of the graft. Procedures such as in a coronary artery bypass grafting (CABG) commonly use vein segments with disabled or disrupted venous valves. 
     There are several procedures known in the art for disabling venous valves. Valvulotome devices are often used to render native venous valves incompetent. Several mechanical valvulotomes have been devised to date to cut valves in veins. The most common valvulotome in use is the mechanical valvulotome, which is an instrument with cutting edges specially designed to be passed into veins to cut the valves mechanically. 
     One disadvantage of the mechanical valvulotome is the possibility of injury to the walls of the vein. Moreover, there is the possibility that a valve could be missed since the valvulotome could slip past the valve. This potential problem is of major concern as it would lead to intraoperative angiograms and increased length of the primary surgical procedure. 
     Preferred valvulotome devices described herein have one or more cutting edges oriented in a manner that reduces potential injury to the walls of the vein. Furthermore, some embodiments provide valvulotome device embodiments comprising structural features adapted to slidably engage a venous valve leaflet. Related delivery devices and kits, as well as methods for using the same, are also provided by embodiments described herein. 
     SUMMARY 
     In some embodiments, a valvulotome device presenting a cutting edge that incisably engages a venous valve leaflet within a body vessel is provided. Preferably, at least a portion of the cutting edge is oriented substantially parallel to the longitudinal axis of the valvulotome device. More preferably, at least a portion of the cutting edge is oriented substantially parallel to the longitudinal axis of the body vessel when the cutting edge is deployed within a body vessel. Some embodiments provide valvulotome devices comprising surfaces configured to slidably engage a venous valve leaflet upon translation of the valvulotome device along the longitudinal axis of a body vessel. 
     In some embodiments, the valvulotome device comprises a means for capturing tissue within a body vessel. The valvulotome device preferably comprises a capturing structural feature, such as a leaflet engaging probe member. 
     In some embodiments, the valvulotome device comprises a means for guiding tissue in a body vessel toward the cutting edge. The valvulotome device preferably comprises a guiding structural feature, such as an angled surface. 
     Some valvulotome device embodiments provide a notch for slidably engaging a venous valve leaflet. In some embodiments, the notch perimeter can be defined by a leaflet engaging probe member, an angled surface or a cutting edge. In some embodiments, the leaflet engaging probe member can be angled with respect to the cutting edge. 
     The valvulotome device preferably comprises one or more valvulotome arms of variable lengths and dimensions. Preferably, one or more valvulotome arms present a cutting edge that incisably engages a venous valve leaflet within a body vessel while at least a portion of the cutting edge is oriented substantially parallel to the longitudinal axis of the valvulotome device, substantially parallel to the longitudinal axis of a body vessel lumen, or both. In some embodiments, the valvulotome device can further comprise valvulotome arms that do not present a cutting edge. Each valvulotome arm preferably comprises a proximal end fixed about a central radial position and a distal end comprising a cutting edge. The distal end is preferably moveable from a radially compressed position to an expanded position. 
     Preferably, the valvulotome arms are contoured to allow the device to open and close in a controlled fashion. The valvulotome arms can be contoured to facilitate movement between a radially-compressed delivery configuration and a radially-expanded deployed configuration. The valvulotome arm can have an angled or twisted conformation. Preferably, the angle of a valvulotome arm with respect to an interior guide wire can be correlated to the amount of translation required to deploy the valvulotome arm at a particular diameter. Angling of a portion of a valvulotome arm can also facilitate closure of the device in a compressed configuration. A portion of a valvulotome arm can be twisted to orient a leaflet-engaging probe member or cutting edge within a body vessel. 
     Some embodiments provide delivery systems comprising a valvulotome device. In some embodiments, the valvulotome device can be compressed to a delivery configuration that is suitable for intraluminal delivery into a body vessel, for example via a catheter. In some embodiments, the valvulotome device can be compressed and retained in a low-profile configuration suitable for translation through the lumen of a body vessel to a point of treatment with minimal disruption of or abrasion to the body vessel. For example, the valvulotome device can be compressed by a flexible outer sheath or ring. Preferably, the valvulotome device can be delivered using a guide wire. In some delivery system embodiments, the valvulotome device can be inserted within a tubular outer sheath that is inserted into the body lumen as part of a catheter-based delivery system. 
     A delivery system preferably comprises a means for monitoring the position or configuration of a valvulotome device, or any portion thereof, in a body vessel. In some embodiments, the valvulotome device further comprises a means for monitoring the position or configuration of the valvulotome device in a body vessel. 
     In some embodiments of the present invention, the valvulotome device or delivery system can be configured to deliver any suitable intraluminal medical device, such as a stent, an occluder, or a prosthetic venous valve. 
     Some embodiments provide methods for using a valvulotome device. One method comprises the step of inserting a valvulotome device into a body vessel. Also provided are methods where a valvulotome device is translated longitudinally (e.g., by sliding) within the body vessel, so that the valve capturing structural feature can mechanically engage a venous valve leaflet. In some methods, a delivery system can be employed to advance a valvulotome device to a first point of treatment (POT). Preferably, this step comprises advancing a delivery system that includes an outer sheath, a valvulotome device and an inner guide wire conduit through a body vessel. Alternatively, this step can comprise advancing a valvulotome device through a tube that has previously been inserted into the body vessel. At the POT, the valvulotome device can be deployed. 
     Some embodiments provide kits comprising a valvulotome device, including kits further comprising a delivery system. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a first cross-sectional view of a first valvulotome device. 
         FIG. 1B  is a second cross-sectional view of the first valvulotome device of  FIG. 1A . 
         FIG. 1C  is a cross-sectional view of a second valvulotome device. 
         FIG. 1D  is a cross-sectional view of a third valvulotome device. 
         FIG. 1E  is a cross-sectional view of a fourth valvulotome device. 
         FIG. 2  depicts a fifth valvulotome device comprising two valvulotome arms. 
         FIG. 3  depicts the fifth valvulotome device of  FIG. 2  in combination with an outer sheath. 
         FIG. 4  depicts the fifth valvulotome device of  FIG. 2  and  FIG. 3  in combination with an outer sheath. 
         FIG. 5  depicts a distal portion of a first delivery system. 
         FIG. 6  depicts a distal portion of the delivery system of  FIG. 5 . 
         FIG. 7A  depicts a proximal portion of a first delivery system. 
         FIG. 7B  depicts a proximal portion of a second delivery system. 
         FIG. 8A ,  FIG. 8B ,  FIG. 8C  and  FIG. 8D  depict a sixth valvulotome device. 
         FIG. 9A ,  FIG. 9B  and  FIG. 9C  depict a seventh valvulotome device. 
         FIG. 10A ,  FIG. 10B  and  FIG. 10C  depict an eighth valvulotome device. 
         FIG. 11A ,  FIG. 11B ,  FIG. 11C  and  FIG. 11D  depict a ninth valvulotome device. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     The following provides a detailed description of some embodiments of the invention, for example, as illustrated by the drawings. The description is not intended to limit the invention in any manner, but rather serves to enable those skilled in the art to make and use the invention. As used herein the terms “comprise(s),” “include(s),” “having,” “has,” “can,” “contain(s),” and variants thereof, are intended to be open-ended transitional phrases, terms, or words that do not preclude the possibility of additional acts or structures. The present invention also contemplates other embodiments “comprising,” “consisting of” and “consisting essentially of,” the embodiments or elements presented herein, whether explicitly set forth or not. 
     The recitation of “about” or “substantially” used with reference to a quantity, such as an angle, includes variations in the recited quantity that are equivalent to the quantity recited, for instance an amount that is insubstantially different from a recited quantity for an intended purpose or function. 
     Preferably, valvulotome devices provided herein are adapted for intraluminal use within a body vessel and methods for their use. More preferably, the valvulotome devices provide a cutting edge for incising tissue within a body vessel. Preferably, the cutting edge can incise a venous valve leaflet. For example, the valvulotome device preferably presents a cutting edge that incisably engages a venous valve leaflet within a body vessel while at least a portion of the cutting edge is oriented substantially parallel to the longitudinal axis of a body vessel lumen. Orientation of the valvulotome device can be monitored using any suitable means. Examples of suitable means include radiopaque markers on the valvulotome device or delivery device, indicia on the delivery device, or emission of a signal by the valvulotome device or the delivery device. 
     As used herein “incisably engage” means to interlock with so that the motion of an incisably-engaged surface is constrained by an engaging surface. Under suitable conditions, further movement of the engaging surface may result in cutting of the engaged surface. For example, a cutting surface “incisably engaging” a tissue surface within a vein refers to a tissue surface positioned in any orientation with respect to a cutting surface so that the tissue surface can be cut by the cutting surface, for example by motion of the cutting surface relative to the tissue surface. A venous valve leaflet positioned across a cutting surface of a notch in a valvulotome arm is one example of an incisably-engaged surface. “Incisable engagement” does not require that the cutting surface actually cut into the first surface, but only that an engaged surface is positioned with respect to the engaging surface in a manner that allows for cutting of the engaged surface upon movement of the cutting surface. 
     A “cutting edge” refers to any surface of the valvulotome that is adapted to cut into a tissue material, such as a venous valve leaflet. For example, a cutting edge can refer to a sharpened or serrated edge, a heated or cooled surface, a vibrating surface, or a chemically-treated portion of any surface. The cutting edge can extend along any suitable portion of the valvulotome body. Some valvulotome devices comprise multiple separate cutting edges. Preferably, a cutting edge is located along portions of the perimeter of a notch structure, such as portions of a leaflet engaging probe member, portions of an angled surface, portions between an angled surface and a leaflet engaging probe member, or any combination thereof. 
     Valvulotome devices preferably comprise means for capturing tissue within a body vessel. Preferably, the valvulotome devices are adapted to capture venous valve leaflet tissue or portions of the vessel wall. Means for capturing tissue include, for example, any structural design of the valvulotome device, selection of materials forming the valvulotome device, coatings on the valvulotome device or modification of the valvulotome device materials that desirably promote the capture of tissue within a body vessel. Preferably, tissue is captured to incisable engage the tissue against a cutting edge. In certain aspects, means for capturing tissue can include portions of the surface of the valvulotome device coated with an adhesive, portions of the valvulotome device that are heated or cooled, serrated, angled, bent, perforated, sharpened or roughened surfaces of the valvulotome device, portions of the valvulotome device coated with biologically active materials that promote capturing tissue within a body vessel, or any combination of two or more of these aspects used in combination in a valvulotome device. 
     Preferably, valvulotome devices provide structural features configured to capture a venous valve leaflet within a body vessel. In one aspect, a valvulotome device comprises one or more surfaces configured to slidably engage a venous valve leaflet upon translation of the valvulotome device along the longitudinal axis of a body vessel. When the valvulotome device is translated longitudinally (e.g., by sliding) within the body vessel, a valve capturing structural feature can mechanically engage a venous valve leaflet. For instance, a capturing feature can be a probe or protrusion that contacts and guides tissue radially inwardly toward a cutting edge upon translation of the capturing feature along the longitudinal axis of the body vessel lumen. 
     Further provided in some aspects are valvulotome devices comprising means for guiding tissue toward a cutting edge. Means for guiding tissue include, for example, any structural design of the valvulotome device, selection of materials forming the valvulotome device, coatings on the valvulotome device or modification of the valvulotome device materials that desirably promote guiding tissue within a body vessel toward one or more cutting edges. The guiding of tissue can be performed in any suitable manner. For instance, tissue can be guided mechanically by relative movement of the guiding surface with respect to the tissue effective to slide the tissue toward a cutting edge. Tissue can also be guided by a guiding structural feature that modifies the flow of fluid in the body vessel so as to direct fluid flow in a manner that directs a portion of the tissue toward a cutting edge. 
     Preferably, the valvulotome device comprises a guiding structural feature in communication with one or more capturing structures, one or more cutting edges, or both a capturing structure and a cutting edge. Preferably, the guiding structural feature cooperates with a means for capturing tissue, for example to entrain tissue toward a cutting edge. In one aspect, a guiding structural feature can be a curved surface positioned in communication with a capturing feature and a cutting edge. Movement of the curved surface relative to the tissue slides the tissue toward the cutting edge, where it can be incisably engaged. In one aspect, the capture feature, the guiding feature and the cutting edge are formed from a single continuous notch or slit in a valvulotome arm. One example of a capture feature is a portion of the valvulotome surface adjacent to and angled with respect to the cutting edge, where the cutting edge is oriented substantially parallel to the vessel wall. 
     More preferably, the valvulotome device comprises a capturing structural feature that is a leaflet engaging probe member; or a guiding structural feature that is an angled surface; as well as the cutting edge. In a valvulotome device comprising both a probe member and an angled surface, the leaflet engaging probe member can be oriented in the same plane as the angled surface, or the leaflet engaging probe member can be oriented out of plane with respect to the angled surface. 
     In some aspects, one or more portions of the material of the valvulotome device, or any portion thereof, can have greater radial resilience, stiffness or compliance than other portions of the device. For example, portions of a cutting edge or a guiding structure can have increased flexibility compared with the capturing feature. In other aspects, a capturing feature can have greater flexibility than a guiding structure or a cutting edge. 
     In a first embodiment, a valvulotome device comprises one or more cutting edges positioned near the distal portion of the valvulotome device. Preferred distal valvulotome device structures permit incisable engagement of tissue in a body vessel by the cutting edge. Various aspects of the first embodiment are illustrated with respect to certain exemplary valvulotome device structures. The first embodiment is not limited to the exemplary valvulotome device structures presented, but also includes any combinations of the features illustrated therein. 
     A first example of a valvulotome device  10  is shown in  FIG. 1A  and  FIG. 1B .  FIG. 1A  shows a first cross-sectional view of the valvulotome device  10 . The valvulotome device  10  has a body  22  having a first body side  23 , an opposing second body side  24 , and a rounded distal body surface  30 . The body  22  can have any suitable cross-sectional configuration. In one aspect, the cross section of the body  22  is curved or U-shaped. In another aspect, the body  22  has a rectangular or circular cross-sectional shape. A longitudinal axis  25  is shown in both  FIG. 1A  and  FIG. 1B .  FIG. 1B  shows a second cross-sectional view of the valvulotome device  10  rotated 90° around the longitudinal axis  25  to show the second body side  24 . 
     The valvulotome body  22  comprises a capturing means that is a capturing structural feature, shown as a leaflet engaging probe member  12 ; a guiding means that is a guiding structural feature, shown as an angled surface  14 ; and a cutting edge  16 . The cutting edge  16  can be a sharpened surface or any surface that will desirably cut tissue that is incisably engaged. One or more cutting edges can be positioned along any portion of the notch  18 . Other structures corresponding to the capturing structural feature, the guiding structural feature or the cutting edge are provided in other valvulotome structures. The perimeter  20  of a notch  18  of the structure shown in  FIG. 1A  extends along the cutting edge  16  and portions of the angled surface  14  and one side of the leaflet engaging probe member  12 . The cutting edge  16  can extend along any portion of the valvulotome body  25 , along portions of the notch perimeter  20 , portions of the leaflet engaging probe member  12 , or any combination thereof. The geometry of the perimeter  20  of the notch  18  can be varied. In  FIG. 1A , the angled surface  14  and the cutting edge  16  are in contiguous communication, and, together with the leaflet engaging probe member  12 , define a notch in a body  18  of the valvulotome device, which is shown as a curvilinear surface. 
     The leaflet engaging probe member  12  can be oriented in any suitable direction and angle with respect to the rest of the valvulotome device  10 . In the valvulotome  10  illustrated in  FIG. 1A  and  FIG. 1B , the leaflet engaging probe member  12  is oriented at a first angle  26  with respect to the cutting surface  16  and at a second angle  28  with respect to the portion of the body  22  that is substantially parallel to the longitudinal axis  25  of the valvulotome device  10 . The first angle  26  and the second angle  28  can be illustrated with respect to  FIG. 1A  and  FIG. 1B , respectively. In  FIG. 1A , a first cross-sectional view of the valvulotome device  10  shows the leaflet engaging probe member  12  defining a portion of the notch  18  that is positioned at the first angle  26  with respect to the cutting edge  16 . The second cross-sectional view of the valvulotome device  10  shown in  FIG. 1B  is obtained by a 90° rotation of the first cross-sectional view of  FIG. 1A  around the longitudinal axis  25  so that the second body side  24  is substantially co-planar with the second cross-sectional view. As shown in  FIG. 1B , a portion of the notch perimeter  20  along one side of a leaflet engaging probe member  12  defines a second angle  28  with respect to the portion of the body  22  that is substantially parallel to the longitudinal axis  25 . The first angle  26  and the second angle  28  can be fixed by forming the leaflet engaging probe member  12  from a rigid material, or variable by forming the leaflet engaging probe member  12  from a flexible material. Preferably, the notch perimeter  20  defines a first angle  26  that is between about 0° and 30°. The leaflet engaging probe member  12  is optionally oriented at a second angle  28  that is between about 0° and 30°. Preferably, the second angle  28  is either 0°, or, when present, is preferably between about 5° and 25°, and more preferably between about 7° and 20°. The first angle  26  and the second angle  28  can be selected to optimize the ease of engagement of tissue in a body vessel. 
     In operation, the body  22  of the valvulotome device can be translated toward a venous valve along the interior of a vein, with the surface of the body  22  or the outer body edge  24  in contact with the interior vessel wall. In operation, as the body  22  is translated toward a leaflet of the venous valve, the leaflet can be incisably engaged by a cutting edge  16  (for example by entraining the leaflet between the leaflet engaging probe member  12  and the angled surface  14 , thereby guiding the leaflet toward the cutting edge  16 ). Once the cutting edge  16  incisably engages the leaflet, further movement of the valvulotome, including translation or twisting of the cutting surface  16  with respect to the leaflet, can incise the leaflet to compromise or disable the venous valve function. 
       FIG. 1C  is a cross-sectional view of a second example of a valvulotome device  40 . The valvulotome device  40  has a body  52  having a first body side  53 , an opposing second body side  54 , and a rounded distal body surface  60 . The body  52  can have any suitable cross-sectional configuration. In one aspect, the cross section of the body  52  is curved or “U”-shaped. In another aspect, the body  52  has a rectangular or circular cross-sectional shape. A longitudinal axis  55  is also shown. 
     The valvulotome body  52  comprises a means for capturing tissue that is a structural feature, shown as a leaflet engaging probe member  42  having a barb  43  that facilitates capture of tissue in a body vessel; a guiding means that is a guiding structural feature, shown as an angled surface  44 ; and a cutting edge  46 . The cutting edge  46  is a sharpened portion of the leaflet engaging probe member  42 . The barb  43  is positioned between the cutting edge  46  and the tip of the leaflet engaging probe member  42 . The perimeter  50  of a notch  48  of the valvulotome device  40  extends along the cutting edge  46  and one side of the leaflet engaging probe member  42 . In  FIG. 1C , the angled surface  44  and the cutting edge  46  are not in contiguous communication. A portion of the leaflet engaging probe member  42  defines the notch  48  of the valvulotome device. The notch perimeter  50  forms a first angle  56  between the cutting surface and the portion of the first body side  53  opposite the cutting surface  46  and substantially parallel to the longitudinal axis  55 . 
     A valvulotome device can optionally comprise multiple cutting edges, or cutting edges that extend outside of a notch structure.  FIG. 1D  is a cross-sectional view of a third example of a valvulotome device  100  that comprises multiple cutting edges. The valvulotome device  100  has a body  150  having a first body side  152 , an opposing second body side  154 , and a rounded distal body surface  156 . The body  150  can have any suitable cross-sectional configuration. In one aspect, the cross section of the body  150  is curved or “U”-shaped. In another aspect, the body  150  has a rectangular or circular cross-sectional shape. 
     The valvulotome body  150  comprises a first leaflet engaging probe member  110  and a second leaflet engaging probe member  130 . The valvulotome body  150  further comprises a guiding means that is a pair of guiding structural features, shown as a first angled surface  112  and a second angled surface  132 . The valvulotome device  100  also comprises a first cutting edge  114  and a second cutting edge  140 . The first cutting edge  114  and the second cutting edge  140  are sharpened edges along the first notch  118  and the second notch  138 , respectively. A segment  115  of the first cutting edge  114  between the first angled surface  112  and the first leaflet engaging probe member  110  is substantially parallel to the longitudinal axis of the valvulotome device  100 . Similarly, a segment  141  of the second cutting edge  140  between the second angled surface  132  and the second leaflet engaging probe member  130  is substantially parallel to the longitudinal axis of the valvulotome device  100 . 
     The valvulotome device  100  comprises several structural features that cooperatively function to capture tissue in a body vessel, for example to incisably engage a venous valve leaflet by relative motion of the body of the valuvlotome with respect to the venous valve leaflet. In one aspect, the position and configuration of the first notch  118  provides a means for capturing tissue. In another aspect, the position and configuration of the second notch  138  provides a means for capturing tissue. Another aspect the combination, configuration or relative orientation or position of the first notch  118  and the second notch  138  provides a means for capturing tissue. A portion of the first cutting edge  114  and the first leaflet engaging probe member  110  in combination with portion of the first body side  152  define the perimeter of the first notch  118  of the valvulotome device. Similarly, a portion of the second cutting edge  140  and the second leaflet engaging probe member  130  in combination with portion of the second body side  154  define the perimeter of the second notch  138  of the valvulotome device. 
     A valvulotome device can optionally comprise multiple notches configured to capture tissue. For example, multiple probes with cutting surfaces can be distributed along the length of a valvulotome device at any suitable angle and relative spacing or orientation to define a plurality of notches.  FIG. 1E  is a cross-sectional view of a fourth example of a valvulotome device  160  that comprises multiple notches with cutting edges. The valvulotome device  160  has a body  162  having a plurality of notches. A first notch  164  comprises a first cutting edge  163 , a second notch  166  comprises a second cutting edge  165 , a third notch  168  comprises a third cutting edge  167 , and a fourth notch  170  comprises a fourth cutting edge  169 . Preferably, at least a portion of each cutting edge is oriented substantially parallel to a wall of a body vessel when the valvulotome device incisably engages tissue. 
     In a second embodiment, the valvulotome device can further comprise one or more valvulotome arms of any suitable length, dimension and spatial orientation with respect to one another. Preferably, the valvulotome arms comprise an elongated structure having a proximal end attached to a delivery device, such as the outer surface of an interior guide wire conduit. Preferably, the valvulotome arms comprise an elongated structure having a distal end that is radially moveable between a radially compact delivery configuration and a radially expanded configuration within a body vessel. More preferably, the distal end of a valvulotome arm comprises a cutting edge positioned near the distal end and is adapted to incisably engage tissue when the valvulotome arm is in the radially-expanded configuration. Most preferably, the distal portion of one or more valvulotome arms comprises a valvulotome structure of the first embodiment. 
     One or more valvulotome arms preferably present a cutting edge that incisably engages a venous valve leaflet within a body vessel. More preferably, at least a portion of the cutting edge is oriented substantially parallel to the longitudinal axis of the valvulotome arm, the longitudinal axis of a body vessel lumen, or both. Preferably, the valvulotome can have 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16 valvulotome arms. Some preferred valvulotome devices comprises 2, 4, or 6 valvulotome arms. Another preferred valvulotome device includes two or more valvulotome arms arrayed in a radially-symmetric fashion about the longitudinal axis of the valvulotome device. For instance, two valvulotome arms can be positioned opposite each other, three valvulotome arms can be arranged at about 120° from each other, and four valvulotome arms can be arranged about 90° apart from each other. Similar arrangements of other numbers of valvulotome arms are similarly provided. In some valvulotome devices, one or more valvulotome arms can have one or more cutting edges. A valvulotome device can optionally comprise one or more valvulotome arms with cutting edges, as well as one or more valvulotome arms without cutting edges. Valvulotome arms can facilitate orientation and use of the valvulotome device, for example by dilating a body vessel or centering the valvulotome device in a body vessel, as well as providing one or more cutting edges to incisably engage tissue. Some preferred valvulotome devices have an even number of valvulotome arms. Valvulotome devices with two or more valvulotome arms preferably have the valvulotome arms arranged radially around an interior longitudinal axis. Preferably, valvulotome devices comprise pairs of valvulotome arms opposably-arranged across from one another. One or more valvulotome arms can comprise self expanding material. However, valvulotome devices having valvulotome arms without self expanding material are also provided. For example, valvulotome arms can be expanded by a balloon or an outwardly-biased spring at the proximal end of a valvulotome arm. 
     The valvulotome device can further comprise a valvulotome arm with a concave U-shaped cross section comprising a capturing structural feature, a guiding feature, or both. Preferably, the valvulotome device can comprise two or more valvulotome arms.  FIG. 2  illustrates a first example of a valvulotome device  200  of the second embodiment. The valvulotome device  200  includes a first valvulotome arm  210  and a second valvulotome arm  250  joined at a first end (not shown) in a V-shape. The valvulotome device  200  comprises a first leaflet engaging probe member  220 ; a first angled surface  230  and a first cutting edge  240 , which are shown in contiguous communication. Together with each leaflet engaging probe member, each angled surface and cutting edge define separate notches (not shown) in the first body  295  and the second body  290 , respectively. While the bodies of the valvulotome arms are shown with U-shaped cross sections in  FIG. 2 , valvulotome arms having bodies with other cross-sectional dimensions and configurations can also be used. For example, the valvulotome arms can be more or less curved along the length of the valvulotome arm body, and the valvulotome arms can have cross-sections that are curved to varying degrees, including crescent-shaped or rectangular cross sections. The valvulotome arms can also have a circular cross section. 
     A valvulotome device can be configured around an inner guide wire conduit formed from any suitable material, for example, a biocompatible polymer. A valvulotome arm preferably closes around a portion of the inner guide wire conduit in a compressed configuration and the inner guide wire conduit can house a guidewire. Preferably, the proximal end of each valvulotome arm is fixedly attached to an inner guide wire conduit. When fully deployed, the proximal end of a valvulotome arm can extend any suitable distance from an internal guide wire conduit. For some applications, such as treatment of human veins, the outside radius measured between the center of the internal guide wire conduit and the proximal end of the valvulotome arms is between about 1.00 mm and about 10.00 mm, and preferably about 2, 3, 4, 5, or 6 mm, any increment of 1.00, 0.50 or 0.25 mm therebetween, or more. For treatment of animal veins, such as bovine veins, the radius is typically in the range of 10.0-20.0 mm, any increment of 1.00, 0.50 or 0.25 mm therebetween, or more. 
     In another aspect, the valvulotome arm can have an angled or twisted conformation. By introducing bends, twists or angles to the configuration of a valvulotome arm, the orientation of the valvulotome device within a body vessel or a cutting edge attached to the valvulotome arm can be adjusted. Preferably, the angle of a valvulotome arm with respect to an interior guide wire can be correlated to the amount of translation required to deploy the valvulotome arm at a particular diameter. Angling of a portion of a valvulotome arm can also facilitate closure of the device in a compressed configuration. In one aspect, a portion of a valvulotome arm can be twisted to orient a leaflet engaging probe member or cutting edge within a body vessel. In  FIG. 2 , the valvulotome device  200  comprises a first valvulotome arm  202  and a second valvulotome arm  204 , both of which have a bent configuration. In  FIG. 3  and  FIG. 4 , the movement of the outer sheath  302  in relation to the first valvulotome arm  202  and the second valvulotome arm  204  results in angle of each valvulotome arm can be adjusted. 
     Preferably, the valvulotome device has a low-profile configuration. For example, in one aspect, a valvulotome device comprises multiple valvulotome arms that are adapted to radially retract to form a low-profile, compressed configuration. In one preferred aspect, the length of two or more adjacent valvulotome arms can be staggered to facilitate compact folding from an expanded to a compressed configuration. 
     The valvulotome device can be self centering within a body vessel. Preferably, radially-symmetric valvulotome arms can facilitate self centering of the valvulotome device in a body vessel. For example, two, three or four valvulotome arms can be disposed in a radially-symmetric fashion to facilitate centering of the device. In another aspect, the valvulotome device maintains the valvulotome arms at a constant radial angle with respect to an interior guide wire upon deployment, for example, by using a Touhy-Borst adapter. In some aspects, the valvulotome device can comprise a first valvulotome arm having a cutting edge and a second valvulotome arm without a cutting edge that facilitates orientation of the valvulotome device within a body vessel. Different valvulotome arms can have different compliance against a body vessel so as to facilitate orientation of the valvulotome device within a body vessel. 
     The valvulotome device can be formed from any suitable material, or combinations of materials. In one aspect, one or more valvulotome arms comprising a cutting edge of the valvulotome device are formed by laser cutting NITINOL® tubing. 
     Preferably, the valvulotome device is self expanding. Upon compression, self expanding valvulotome devices can expand toward their pre-compression geometry. In some aspects, a selfexpanding valvulotome device can be compressed into a low-profile delivery configuration and then constrained within a delivery system for delivery to a point of treatment in the lumen of a body vessel. At the point of treatment, the self expanding valvulotome device can be released and allowed to subsequently expand to another configuration. 
     In certain embodiments, the valvulotome device is formed partially or completely of alloys such as Nickel-Titanium alloys (NiTi), including those sold under the tradename NITINOL® or TINEL®. The valvulotome can also be made in whole or in part from other materials including cobalt-chromium; stainless steel (including 302-304, 316, and 400 series); elgiloy; phynox; MP35N; cobalt-chromium alloys; diamond-like carbon; tungsten; a nickel-iron-chromium alloy such as those sold under the tradename ICONEL®; aluminum; titanium; or other titanium alloys; or platinum, gold or other noble metals. The valvulotome device can also be coated with a lubricant or a bioactive coating, such as an antibiotic optionally combined with a polymer carrier. 
     Preferably, valvulotome devices comprise self expanding valvulotome arms comprising superelastic alloys. Alloys having superelastic properties generally have at least two phases: a martensitic phase, which has a relatively low tensile strength and which is stable at relatively low temperatures, and an austenitic phase, which has a relatively high tensile strength and which can be stable at temperatures higher than the martensitic phase. For example, superelastic characteristics can generally allow a NiTi valvulotome to be deformed by collapsing the valvulotome and creating stress which causes the NiTi to reversibly change to the martensitic phase. The valvulotome can be restrained in the deformed condition inside an outer sheath typically to facilitate the insertion into a patient&#39;s body, with such deformation causing the isothermal phase transformation. Once within the body lumen, the restraint of the outer sheath on the valvulotome can be removed, thereby reducing the stress thereon so that the superelastic valvulotome returns toward its original undeformed shape through isothermal transformation back to the austenitic phase. 
     The shape memory effect allows a NiTi structure to be deformed to facilitate its insertion into a body lumen or cavity, and then heated within the body so that the structure returns to its original, set shape. 
     Shape memory effect can be imparted to an alloy useful in constructing a self expanding valvulotome by heating the nickel-titanium metal to a temperature above which the transformation from the martensitic phase to the austenitic phase can be complete; i.e., a temperature above which the austenitic phase can be stable. The shape of the metal during this heat treatment can be the shape “remembered.” The heat-treated metal can be cooled to a temperature at which the martensitic phase can be stable, causing the austenitic phase to transform to the martensitic phase. The metal in the martensitic phase can be then plastically deformed, e.g., to facilitate the entry thereof into a patient&#39;s body. Subsequent heating of the deformed martensitic phase to a temperature above the martensitic to austenitic transformation temperature causes the deformed martensitic phase to transform to the austenitic phase. During this phase, transformation of the metal reverts back towards its original shape. 
     The recovery or transition temperature may be altered by making minor variations in the composition of the metal and in processing the material. In developing the correct composition, biological temperature compatibility must be determined in order to select the correct transition temperature. In other words, when the valvulotome can be heated, it must not be so hot that it can be incompatible with the surrounding body tissue. Other shape memory materials may also be utilized, such as, but not limited to, irradiated memory polymers such as autocrosslinkable high-density polyethylene (HDPEX). Shape memory alloys are known in the art and are discussed in, for example, “Shape Memory Alloys,” Scientific American, Vol. 281, pp. 74-82 (November 1979), incorporated herein by reference. 
     Preferably, the valvulotome arms can be moved between a radially-compressed delivery configuration and a radially-expanded configuration in a gradual, controllable manner. Valvulotome arms can be contoured to facilitate radial compression and housing of the valvulotome arm in a radially compressed configuration. Preferably, an annular outer sheath is positioned around one or more radially self expanding valvulotome arms so as to compress the valvulotome arms into the radially-compressed delivery configuration. By controlling the longitudinal translation of the outer sheath with respect to one or more of the enclosed valvulotome arms, the radial position of the enclosed valvulotome arms can be controlled. Movement of the outer sheath from the proximal toward the distal end of the enclosed valvulotome arms results in radial expansion of the valvulotome arms, and movement of the outer sheath in the opposite direction radially compresses the valvulotome arms. In one aspect, the valvulotome arms can be contoured to facilitate movement between a low-profile, radially-compressed delivery configuration and a radially-expanded deployed configuration. 
     In general, an outer sheath can be a flexible, kink-resistant introducer sheath, as described in U.S. Pat. No. 5,380,304, which is incorporated in its entirety herein by reference. The outer sheath preferably comprises one or more radiopaque regions for imaging the outer sheath within a body vessel. 
       FIG. 3  and  FIG. 4  illustrate the controlled expansion of the valvulotome device  200 , where the valvulotome device is made from a self-expanding NiTi alloy material. The valvulotome device  200  comprises a first valvulotome arm  202  and a second valvulotome arm  204 , each having a U-shaped cross section, and are joined together at a common proximal end  206 .  FIG. 3  shows the valvulotome device  200  in a partially-expanded state  300 . An outer sheath  302  in the position  350  encloses the common proximal end  206  of the valvulotome device  200  and constrains the valvulotome arms from attaining a fully radially-expanded configuration. In  FIG. 4 , the outer sheath  302  is translated in the direction of the proximal end of the valvulotome arms, exposing the common proximal end  206  and allowing the first valvulotome arm  202  and the second valvulotome arm  204  to achieve a fully radially-expanded configuration  400 . The two valvulotome arms are spaced progressively farther apart as they expand apart from each other, as the outer sheath  302  is moved in the proximal direction with respect to the valvulotome arms  202 ,  204 . For comparison with the fully expanded comfiguration  400 , the position of the outer sheath  350  and the valvulotome arms in the partially-expanded state  300  is also indicated in  FIG. 4 . 
     In a third embodiment, delivery systems are provided. A delivery system preferably comprises a valvulotome device in a radially-compressed configuration within an outer sheath. The valvulotome device can be compressed to a delivery configuration that is suitable for intraluminal delivery into a body vessel, for example via a catheter. In some aspects, the valvulotome device can be compressed and retained in a low-profile configuration suitable for translation through the lumen of a body vessel to a point of treatment with minimal disruption of or abrasion to the body vessel. For example, the valvulotome device can be compressed by a flexible outer sheath or ring. In some delivery systems, the valvulotome device can be inserted within a tubular outer sheath that is inserted into the body lumen as part of a catheter-based delivery system. 
     Preferred delivery devices also comprese an inner guide wire conduit. The valvulotome device is preferably annularly configured around an interior guide wire tube conduit. The interior guide wire conduit preferably is adapted to house a guide wire to direct the valvulotome device and a delivery catheter to a point of treatment through the lumen of a body vessel. Preferably, the proximal ends of each arm of the valvulotome device is fixedly attached to an inner guide wire conduit. The inner guide wire conduit can be made of any suitable material, such as a polyamide polymer material. The valvulotome device can also be disposed adjacent to an inner guide wire conduit, or be delivered separately from the inner guide wire conduit. 
     In one aspect, the valvulotome device can be delivered using an “over-the-wire” technique that employs a guide wire to deliver the valvulotome device through a body vessel. In this aspect, the blood vessel into which a valvulotome device is to be inserted can be punctured, a thin guide wire generally being about twice the length of the distal lumen (i.e., the channel whose end is furthest away from the operator), which ends centrally relative to the round cross section at the tip of the catheter, is advanced in the blood vessel via the puncture cannule. After the guide wire has been advanced, the puncture cannule is removed by pulling back via the wire. A dilator catheter is then advanced in the vessel via the guide wire. A dilator catheter is preferably a relatively robust and rigid single-lumen catheter made of a plastic material and having a distal tip tapering to the diameter of the guide wire. The purpose of the dilator catheter is to expand the puncture channel through skin, fat and muscle tissue and the blood vessel wall to the diameter of the catheter. After expansion, the dilator catheter is removed, the guide wire remains in the blood vessel with the distal tip. The free proximal (i.e. closest to the operator) end of the guide wire is then inserted into the tip of the catheter also tapered toward the guide wire diameter and advanced into the blood vessel via the guide wire. As soon as the catheter is correctly positioned, the guide wire is pulled out of the so-called distal lumen; thus, the distal lumen of the catheter is available for other uses, such as delivery of a valvulotome device. 
       FIG. 5  shows a portion of a delivery system  500  comprising a flexible outer sheath  520  enclosing a self expanding valvulotome device  510  in a compressed delivery conformation and an inner guide wire conduit  530 .  FIG. 6  shows a delivery system  600  substantially similar to the delivery system  500  of  FIG. 5 , except that the outer sheath  620  has been retracted from the valvulotome device  610 . When the outer sheath  620  is retracted away from the valvulotome device  610 , the plurality of valvulotome arms  612  of the self-expanding valvulotome device  610  expand away from the compressed formation toward a deployment configuration. Each valvulotome arm  612  comprises a cutting edge, an angled surface and a leaflet engaging probe member that together define a notch. For example, a first leaflet engaging probe member  616 , a second leaflet engaging probe member  646 , a first angled surface  614 , a second angled surface  642 , and a second cutting edge  644  are all labeled in  FIG. 6 . Also shown in  FIG. 6  are a flexible outer sheath  620 , which has been retracted to deploy the valvulotome device  610 , and an inner guide wire conduit  630 . 
     Preferably, the delivery system provides for the controlled radial deployment of one or more valvulotome arms within a body vessel. For example, a valvulotome comprising self expanding valvulotome arms enclosed in an outer sheath can be deployed by the relative motion between the outer sheath and the self expanding valvulotome arms. For example, as shown in  FIG. 7A , a proximal portion of a delivery device  700  is shown, having a distal end  750  in communication with a self expanding valvulotome device (not shown) that is enclosed in an outer sheath within a body vessel. Movement of the proximal handle  710  of the delivery device  700  moves the outer sheath (not shown) relative to the valvulotome device within a body vessel. The proximal handle  710  can be translated in relation to the distal handle  720 , which is attached to a section of tubular conduit  740 . Movement of the outer sheath  740  relative to an interior guide wire conduit  745  radially expands or contracts the valvulotome arms of the valvulotome device, thereby adjusting the position of one or more cutting edges of the valvulotome device. 
     The valvulotome device preferably comprises a means for monitoring the position or the position and configuration of a valvulotome device, or any portion thereof, in a body vessel. For example, the valvulotome device can comprise a radiopaque marker. Radiopaque markers can be incorporated in or placed on any suitable portion of the valvulotome device or a delivery system, such as on the outer sheath, the inner guide wire conduit or a radiopaque tip distal to the outer sheath. 
     Incorporation of a radiopaque material can be useful, for example, to facilitate tracking and positioning of the valvulotome device. The radiopaque material may be added in any fabrication method or absorbed into or sprayed onto the surface of part or all of the medical device. The degree of radiopacity contrast can be altered by the type and amount of material incorporated into the device. Radiopacity may be imparted by covalently binding iodine to the polymer monomeric building blocks of the elements of the implant. Common radiopaque materials include barium sulfate, bismuth subcarbonate, and zirconium dioxide. Other radiopaque elements include: cadmium, tungsten, gold, tantalum, bismuth, platium, iridium, and rhodium. Radiopacity is typically determined by fluoroscope or x-ray film. 
     In a preferred aspect, the valvulotome delivery device comprises a tip, an outer sheath comprising a radiopaque material, or both. The tip can be positioned distal to one or more valvulotome arms in a compressed state. When the radiopaque material is incorporated at the distal end of the outer sheath and in the tip, the deployment of the valvulotome arms between the two points can be correlated to the separation of the radiopaque markers in the tip and the outer sheath. |Radiopaque markers on the valvulotome device or the delivery device can also be used in combination with indicia on the delivery device corresponding to the position or orientation of the valvulotome device or portions thereof. For instance, a delivery device handle can include markings correlated to the radial expansion of valvulotome device within a body vessel.| 
     The valvulotome delivery device also preferably comprises a means for monitoring the position and configuration of a valvulotome device, or any portion thereof, in a body vessel. For example, the position of the cutting edge, or degree of radial expansion of one or more valvulotome arms of the valvulotome can be provided to a user of the delivery device by any suitable means. In one aspect, the delivery system comprises indicia correlated to the position or orientation of the valvulotome device. Any suitable form of indicia can be used to provide the user of the delivery device with information about the position and radial dimensions of the valvulotome device in a body vessel. Suitable indicia include markings on portions of the delivery device, light emitting diodes (LED) and emission of a signal from the valvulotome or delivery device. 
     In one aspect, markings on portions of the delivery device can correlate to the translation of a handle with the radius of the valvulotome device in a body vessel. With respect to  FIG. 7A , the delivery device  700  comprises indicia  730  to correlate the translation of the proximal handle  710  with respect to the distal handle  720  to the simultaneous radial expansion of the valvulotome arms of the valvulotome device. The distal end  750  of the delivery device  700  is inserted into a body vessel. When the distal handle  720  is at a first position  732 , an outer sheath  740  completely covers the valvulotome device in the radially compressed configuration. The cutting edge(s) of the valvulotome are not exposed when the distal handle  720  is in the first position  732 . When the distal handle  720  is translated toward the proximal handle  710 , the outer sheath  740  is gradually pulled back to radially expand the valvulotome arms of the valvulotome device in a controlled manner. At a second position  734 , the valvulotome arms are partially expanded within the body vessel. At a third position  736 , the outer sheath no longer covers any portion of the fully-expanded valvulotome device. The cutting edge(s) of the valvulotome are fully exposed when the distal handle  720  is in the third position  736 . 
     In another aspect, a digital LED display or color change of an indicator region can provide information about the position or orientation of a valvulotome device in a body vessel. For example, in  FIG. 7B , a proximal portion of a delivery device  760  is shown that is the same as the proximal portion of the delivery device  700  shown in  FIG. 7A , except that a series of indicator lights correlate the position of the proximal handle  770  with the radial expansion of the valvulotome arms of a valvulotome device. Instead of the indicia  730  on the delivery device  700  in  FIG. 7A , the proximal handle  770  has a first indicator light  772  that is illuminated when the distal handle  780  is in the first position  733 , a second indicator light  774  that is illuminated when the distal handle  780  is in the second position  735 , a third indicator light  776  that is illuminated when the distal handle  780  is in the third position  737 . Appropriate combinations of electronic and mechanical connections are employed in the delivery device so that the illumination of an indicator light reflects the radial deployment state of the valvulotome inside a body vessel in real time. In another aspect, the delivery system provides information via the internet as to the position, orientation or radial deployment of a valvulotome device. For example, the delivery device can transmit a signal detected by a laptop computer as, for example, an internet signal. In one aspect, the delivery system comprises one or more disposable parts. 
     In a fourth embodiment, the valvulotome device or delivery system can further comprise any suitable intraluminal medical device, such as a stent, an occluder, and a prosthetic venous valve. The intraluminal medical device can comprise a self expanding or balloon-expandable device. For example, one or more intraluminal medical devices can be contained within a retractable outer sheath and deployed upon retraction of the outer sheath. In one aspect, retraction of an outer sheath deploys one or more valvulotome arms and further retraction of the outer sheath deploys an implantable venous valve. Methods of supplying intraluminal medical devices are also provided, for example, for treating human or veterinary patients in which it is desirable to deploy multiple intraluminal medical devices in a body vessel, for example in conjunction with procedures using the valvulotome device. 
     For example, the valvulotome device or the delivery system can further comprise a prosthetic or remodelable venous valve. The delivery systems and methods can deploy different types of intraluminal medical devices in a single procedure and/or vessel. For example, it may be desirable to deploy a prosthetic venous valve at one location in a vessel, and deploy a self-expandable stent at another location in the same vessel after using a valvulotome. Thus, any suitable combination of intraluminal medical devices can be used in the devices, kits and methods described herein. Any suitable prosthetic valve can be utilized in the devices and methods. Examples of suitable valves and delivery devices are disclosed in U.S. Patents and Published Patent Application Nos. 2004/0260389A1 (“Artificial valve prosthesis with improved flow dynamics”); 2004/0186558A1 (“Implantable vascular device”); 2004/0167619A1 (“Prosthesis adapted for placement under external imaging”); 2003/0144670A1 (“Medical device delivery system”); 2003/0125795A1 (“Multiple-sided intraluminal medical device”); U.S. Pat. No. 6,508,833 (“Multiple-sided intraluminal medical device”); and U.S. Pat. No. 6,200,336 (“Multiple-sided intraluminal medical device”). Each of these references is hereby incorporated into this disclosure in its entirety for the express purpose of describing suitable implantable medical devices and delivery systems for use in and with the devices, kits, and methods described herein. The exact combination and number of intraluminal medical devices used in any particular method or included in any particular kit will depend on various factors, including the condition being treated. 
     In a fifth embodiment, methods of using a valvulotome device are provided herein. One method comprises the step of inserting a valvulotome device into a body vessel. For example, a delivery system can be employed to advance a valvulotome device to a first point of treatment (POT). Preferably, this step comprises advancing a delivery system that includes an outer sheath, a valvulotome device and an inner guide wire conduit through a body vessel. Alternatively, this step can comprise advancing a valvulotome device through a tube that has previously been inserted into the body vessel. 
     At the POT, the valvulotome device can be deployed. The manner in which this step is accomplished will depend on the arrangement of the valvulotome device within the delivery system. For example, if the valvulotome device is disposed annularly around an inner guide wire conduit, the valvulotome device can be deployed by withdrawing the outer sheath to expose the valvulotome device and allow self expansion of the valvulotome device to occur. In other embodiments, the valvulotome device can be contained within a lumen of an outer sheath previously inserted into a body vessel and pushed in its compressed configuration to a POT. At the POT, the valvulotome device can be deployed simply by forcing the medical device out of an end of a lumen. 
     In a sixth embodiment, methods of treatment are provided. In one aspect, a method of treating or preventing a venous valve-related condition, such as Venous Valve Insufficiency (VVI), is provided. A “venous valve related condition” means any medical condition presenting symptoms commensurate with impaired venous valve function. 
     Other aspects provide methods of inducing venous valve insufficiency, for example, to create an animal model with one or more insufficient venous valves. 
     Also provided are methods of impairing the function of one or more venous valves. More generally, methods of cutting tissue within any body vessel are provided. 
     In a seventh embodiment, kits comprising a valvulotome device and a delivery system are provided, including kits comprising a catheter-based delivery system and a valvulotome device. Kits comprising a valvulotome device and an implantable venous valve or stent are also provided. 
     The foregoing disclosure includes the best mode known to the inventor for practicing the invention. It is apparent, however, that those skilled in the relevant art will recognize variations of the invention that are not described herein. While the invention is defined by the appended claims, the invention is not limited to the literal meaning of the claims, but also includes these variations. 
     The recitations of “embodiments,” “one embodiment,” “some embodiments,” “other embodiments,” “illustrative embodiments,” “selected embodiments,” “certain embodiments,” and “another embodiment” herein are synonymous. All of these recitations, and “aspects” thereof, refer to illustrative embodiments and are not exclusive of each other or of other embodiments not recited herein. Accordingly, the invention also provides embodiments that comprise combinations of one or more of the illustrative embodiments described above. 
     All references cited herein are hereby incorporated into this disclosure in their entirety. 
     EXAMPLES 
     The following Examples are offered for the purpose of illustrating the present invention and are not to be construed to limit the scope of this invention. Any combination of features described in embodiments of the invention, including those provided below, are also within the scope of the invention. 
     Example 1 
     A Four-Staggered Valvulotome Arm Valvulotome Device Having Four Cutting Edges 
       FIG. 8A  and  FIG. 8B  show a portion of a first valvulotome device  800  comprising two longer valvulotome arms  810  radially disposed in an alternating fashion with two shorter valvulotome arms  812 . The longer valvulotome arms  810  are formed from laser-cut NiTi alloy and have a curved cross section with an outside diameter of 0.086-inch. The short valvulotome arms  812  are formed from laser-cut NiTi alloy and have a curved cross section with an outside diameter of 0.065-inch. Each of the longer valvulotome arms  810  and the shorter valvulotome arms  812  comprise a probe  860 , a guiding edge  862  and a cutting edge  864  to form a notch at the distal end of each valvulotome arm. The longer valvulotome arm  810  has a greater length than the shorter valvulotome arms  812 , and the distal ends of the longer valvulotome arm  810  have a curved portion  866  that align the cutting edge  864  to be substantially parallel to a guidewire  850 . The shorter valvulotome arms  812  are straight, without a curved portion. In this example, each valvulotome arm is positioned at a 90° angle with respect to every other valvulotome arm.  FIG. 8C  and  FIG. 8D  show a compressed configuration, where the shorter valvulotome arms  812  are staggered with the longer valvulotome arms  810  so as to promote closing of the device to a compressed configuration. Translation of either an outer sheath  830  toward the radiopaque tip  840 , or translation of the valvulotome arms away from the radiopaqe tip  840 , compresses the arms into the compressed configuration. The valvulotome arms shown are laser-cut from a NITINOL® cannula. 
     The portion of the first valvulotome device  800  shown in  FIG. 8A  also includes an outer sheath  830  containing the cutting valvulotome arms  810  and the guiding valvulotome arms  812 , an inner guide wire conduit  820 , a guidewire  850  and a radiopaque tip  840 . The valvulotome arms are pressed against the inner guide wire conduit  820  in the compressed configuration. The radiopaque tip  840  is made of stainless steel and is readily visible in a body vessel using imaging techniques such as x-rays. The first valvulotome device  800  can be translated along the guidewire  850  to a point of treatment. 
     Example 2 
     A Four-Valvulotome-Arm Valvulotome Device Having Four Cutting Edges 
       FIG. 9A ,  FIG. 9B , and  FIG. 9C  show a portion of a second exemplary valvulotome device  900  comprising four valvulotome arms of equal length. Each valvulotome arm  910  has a probe  960 , a guiding edge  962  and a cutting edge  964 . This valvulotome device  900  is similar to the first valvulotome device  800 , except that each valvulotome arm is the same length. As seen in  FIG. 9B , the second valvulotome device  900  also comprises an outer sheath  930 , an inner guide wire conduit  920 , a radiopaque tip  940  and a guidewire  950 . As seen in  FIG. 9C , the radiopaque tip  940  is positioned closer to the distal end of the valvulotome arms  910  in the compressed state, as compared to the first valvulotome device  800 . 
     Example 3 
     A Two-Valvulotome-Arm Valvulotome Device Having Two Cutting Edges 
       FIG. 10A  shows a portion of a third exemplary valvulotome device  1000  having two valvulotome arms  1010  oppositely disposed from each other, as well as an inner guide wire conduit  1020  and a radiopaque tip  1040 . As seen in  FIG. 10B  and  FIG. 10C , each valvulotome arm  1010  comprises a guiding edge  1062 , a cutting edge  1064  and a probe  1060  that together define a notch. In this example, each valvulotome arm is positioned at 180° from the other. The third valvulotome device  1000  is otherwise similar to the first valvulotome device  800 . 
     Example 4 
     A Two-Valvulotome-Arm Valvulotome Device Having Tapered Valvulotome Arms and an Inward-Facing Probe 
       FIG. 11A  and  FIG. 11B  show a portion of a fourth exemplary valvulotome device  1100  having two valvulotome arms  1110  oppositely disposed around an inner guide wire conduit  1120 . As shown in  FIG. 11C  and  FIG. 11D , each valvulotome arm  1110  has a probe  1160 , a guiding edge  1162  and a cutting edge  1164 . The radiopaque tip  1140  is more elongated than that of the first valvulotome device  800 . Translation of the outer sheath  1130  toward the radiopaque tip  1140  compressed the valvulotome arms against the inner guide wire conduit  1120  from the expanded configuration to the compressed configuration. In this example, each valvulotome arm is positioned at 180° with respect to the other valvulotome arm. The fourth valvulotome device  1100  is otherwise similar to the first valvulotome device  800 .