Abstract:
A method for preparing a graft vessel for anastomosis to a target vessel includes making at least one incision in the graft vessel, such as to form a flap at an end thereof. The graft vessel and/or a fixture, such as a clamp, may be positioned relative to one another, such as to form an angle relative to one another, prior to making the incision or incisions. The position of the graft vessel relative to the fixture may be based on the size of the opening in the target vessel at the anastomosis site.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This application is a continuation of U.S. patent application Ser. No. 10/367,175, filed on Feb. 14, 2003, which is incorporated by reference in its entirety.  
           [0002]    1. Field of the Invention  
           [0003]    The present invention relates generally to preparing blood vessels for a vascular anastomosis procedure.  
           [0004]    2. Description of Related Art  
           [0005]    Vascular anastomosis is a procedure where two separate blood vessels of a patient are surgically grafted together. The vascular anastomosis procedure is routinely performed during the treatment of a variety of conditions, including coronary artery disease, diseases of the great and peripheral vessels, organ transplantation and other types of trauma. When a patient suffers from coronary artery disease (CAD), an occlusion or stenosis in a coronary artery restricts blood flow to the heart muscle. In order to treat CAD, the area where the occlusion occurs is bypassed. The area is bypassed through rerouting blood flow by grafting a vessel in the form of either a prosthesis, a harvested artery or a vein. When the vessel is grafted to bypass the blocked coronary artery, the occlusion is avoided and adequate blood flow is restored to the heart muscle. This treatment is known as coronary artery bypass grafting (CABG).  
           [0006]    When a CABG is performed, a large incision is made in the chest of a patient and the sternum is separated in order to allow access to the heart of the patient. Moreover, the patient is connected to a heart lung machine which circulates the blood of the patient. After the heart lung machine is connected to the patient, the patient&#39;s heart is stopped in order to perform the vascular anastomosis. However, stopping the patient&#39;s heart is very traumatic to the patient.  
           [0007]    In order to minimize the trauma to the patient induced by the CABG, less invasive techniques have been used. These less invasive techniques include performing a series of small incisions in the patient&#39;s chest. Once the incisions are completed, surgery is performed with the aid of visualizing scopes. The less invasive techniques may be performed on a beating heart in order minimize trauma to the patient, thereby avoiding the need for cardiopulmonary bypass.  
           [0008]    In both conventional and less invasive CABG techniques, a surgeon sutures one end of the graft vessel to the coronary artery and the other end of the graft vessel to a blood supplying vein or artery, such as the aorta, in order to bypass the occlusion. Prior to suturing the graft vessel to the arteries, called target vessels, an incision is made in the target vessel to allow suturing of the graft vessel to the target vessel. Typically, the surgeon cuts the incision in the target vessel to an appropriate length depending on a size of the graft vessel in order to suture the graft vessel to the target vessel. However, a great amount of skill and time is required in making the incision due to the small size of the graft vessel. Likewise, time and skill is required in aligning the graft vessel to the incision. Performing the anastomosis is further compounded by the small size and the flexible, circular configuration of the of the graft vessel. In addition, the surgeon has difficulties holding and suturing in the graft vessel due to the small size and the flexible, circular configuration of the blood vessel.  
           [0009]    Accordingly, a need exists for an automated method which allows a surgeon to make a precise anastomosis between a graft vessel and a target vessel. This new method should implement a grafting tool which allows a surgeon to control the thin and difficult to handle tissue of the graft and target vessel. Moreover, it would be desirable to implement a grafting tool which allows for making incisions in a graft vessel to establish a predetermined length which matches a length of an incision in a target vessel.  
         BRIEF SUMMARY OF THE INVENTION  
         [0010]    The present invention fills the aforementioned needs by providing a graft vessel preparation device which prepares a graft vessel for a vascular anastomosis procedure. The present invention also provides a method for preparing a graft vessel for a vascular anastomosis procedure using the graft vessel preparation device.  
           [0011]    In one embodiment of the present invention, a graft vessel preparation device for preparing a graft vessel is disclosed. The graft vessel preparation device prepares the graft vessel for a vascular anastomosis procedure. The preparation device comprises a spreader, a critical dimension locator and a clamp. The spreader is configured to receive and stretch an end portion of the graft vessel. The critical dimension locator is configured to establish a critical dimension on the graft vessel after the graft vessel is placed over the spreader. The clamp coordinates both the spreader and the critical dimension locator in order to fix the critical dimension on the graft vessel. The critical dimension allows for precise grafting of the graft vessel to a coronary artery during a vascular anastomosis procedure.  
           [0012]    In a further embodiment of the present invention, a graft vessel preparation device for preparing a graft vessel for a vascular anastomosis procedure is disclosed. The preparation device comprises a parallelogram linkage, a first spreader arm and a second spreader arm. The first spreader arm and the second spreader arm are mounted on opposing members of the parallelogram linkage such that the first spreader arm and the second spreader arm are parallel to one another. The parallelogram linkage also provides motion to the spreader arms whereby the spreader arms are movable with respect to each other. Also, the spreader arms are configured to receive an end of a graft vessel as the graft vessel is placed on to the graft vessel preparation device. Moreover, the spreader arms separate from one another to establish a critical dimension on the graft vessel.  
           [0013]    In another embodiment of the present invention, a graft vessel preparation device for preparing a graft vessel for a vascular anastomosis procedure is disclosed. The graft vessel preparation device includes a base, first and second spreader arms, an extension link and a holding clamp. The base includes a first part and a second part which are movable with respect to each other. The first and second spreader arms are attached to the first and second parts of the base of the graft vessel preparation device. Also, the spreader arms are configured to receive an end of the graft vessel when the graft vessel is placed over the spreader arms. The extension link of the graft vessel preparation device is rotatably attached to the base and is configured to separate the first and second spreader arms. The holding clamp of the graft vessel preparation device is substantially aligned with the extension link and clamps the graft vessel.  
           [0014]    In yet another embodiment of the present invention, a method for preparing a graft vessel for an anastomosis procedure using a graft vessel preparation device is disclosed. The graft vessel preparation device includes spreader arms that are movable with respect to each other. The method comprises placing the graft vessel over the spreader arms such that the spreader arms occupy an interior of the graft vessel. Once the graft vessel is placed over the spreader arms, the spreader arms are moved from one another to stretch the graft vessel. A critical dimension is then established once the graft vessel is stretched. The critical dimension is established by moving the spreader arms away from one another with the parallelogram linkage.  
           [0015]    In a further embodiment of the present invention, a graft vessel flapper is disclosed. The graft vessel flapper comprises spreader arms which are movable with respect to each other and a clamp. The clamp, which is rotatable with respect to the spreader arms, clamps a graft vessel placed over the spreader arms. In addition, the clamp establishes a critical dimension of the graft vessel.  
           [0016]    In another embodiment of the present invention, a method for preparing a graft vessel using a graft vessel preparation device is disclosed. The method includes forming an incision in a target vessel such that an incision perimeter is formed in the target vessel. The graft vessel is then prepared by establishing and maintaining a critical dimension of the graft vessel. The critical dimension is formed on the graft vessel such that the perimeter of the critical dimension is the same as the incision perimeter of the target vessel. The congruity of between the incision perimeter of the target vessel and the perimeter of the of the critical dimension allow for proper grafting of the graft vessel to the target vessel during a vascular anastomosis procedure.  
           [0017]    As may be appreciated, the present invention provides a device which allows an automated method for preparing graft vessels for a vascular anastomosis procedure. The present invention precisely and accurately slices a graft vessel such that the graft vessel will graft with a coronary artery during the vascular anastomosis procedure.  
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0018]    Many advantages of the present invention will be apparent to those skilled in the art with a reading of this specification in conjunction with the attached drawings, wherein like reference numerals are applied to like elements and wherein:  
         [0019]    FIG. 1 is a schematic top view of a graft vessel preparation device having a graft vessel inserted over spreader arms in preparation for grafting, in accordance with one embodiment of the present invention.  
         [0020]    FIG. 2 illustrates a schematic top view of the graft vessel preparation device of FIG. 1 where spreader arms are separated by a tension spring, in accordance with one embodiment of the present invention.  
         [0021]    FIG. 3 is a top view of the graft vessel preparation device of FIG. 2 which shows a second clamp portion attached to a first clamp portion, in accordance with one embodiment of the present invention.  
         [0022]    FIG. 4A is a schematic top view of the graft vessel preparation device of FIG. 3 illustrating incisors slicing a graft vessel, in accordance with one embodiment of the present invention.  
         [0023]    FIG. 4B shows perspective view of a graft vessel more clearly illustrating a critical dimension Y on the graft vessel, in accordance with one embodiment of the present invention.  
         [0024]    FIG. 4C illustrates an isometric view of the insertion of a anastomosis tool having an anvil into a target vessel, in accordance with one embodiment of the present invention.  
         [0025]    FIG. 4D is an isometric view of die target vessel showing the stabilization of target vessel after the anvil is inserted into the target vessel.  
         [0026]    FIG. 4E shows a side view of the spreader arm of FIG. 4A which more clearly shows grooves in the side of the spreader arm, in accordance with one embodiment of the present invention.  
         [0027]    FIG. 5 illustrates a schematic top view of the graft vessel preparation device of FIG. 4A where the graft vessel is removed from the graft vessel preparation device, in accordance with one embodiment of the present invention.  
         [0028]    FIG. 6 is a side view of the clamp of the graft vessel preparation device of FIG. 5 formed by a first clamp portion and a second clamp portion in accordance with one embodiment of the present invention.  
         [0029]    FIG. 7 illustrates a side view of the clamp of FIG. 6 being inserted onto a anastomosis tool in accordance with one embodiment of the present invention.  
         [0030]    FIG. 8 illustrates a method for slicing a graft vessel in preparation for a grafting procedure in accordance with one embodiment of the present invention.  
         [0031]    FIG. 9 illustrates a perspective view of graft vessel preparation device in accordance with an embodiment of the present invention.  
         [0032]    FIG. 10A shows a side view of a spreader of the graft vessel preparation device of FIG. 9, in accordance with one embodiment of the present invention.  
         [0033]    FIG. 10B illustrates a side view of the spreader of FIG. 10A, where the spreader is in a locked position in accordance with one embodiment of the present invention.  
         [0034]    FIG. 11 shows a side view of the spreader of FIG. 10A, where graft vessel placed over the spreader in accordance with another embodiment of the present invention.  
         [0035]    FIG. 12 shows a perspective view of a critical dimension locator of the graft vessel preparation device of FIG. 9, in accordance with one embodiment of the present invention.  
         [0036]    FIG. 13A is an embodiment of the present invention where the spreader and graft vessel of FIG. 10B are engaged with the critical dimension locator of FIG. 12.  
         [0037]    FIG. 13B shows the spreader and the graft vessel of FIG. 13A rotated clockwise within the critical dimension locator of FIG. 13A in order to establish a critical dimension Y in accordance with one embodiment of the present invention.  
         [0038]    FIG. 14A shows a perspective view of a second clamp half of the graft vessel preparation device of FIG. 9, in accordance with one embodiment of the present invention.  
         [0039]    FIG. 14B shows a bottom view of the second clamp half of FIG. 14A, in accordance with one embodiment of the present invention.  
         [0040]    FIG. 15 shows a top view of the slicing of the graft vessel of FIG. 13B with incisors in accordance with one embodiment of the present invention.  
         [0041]    FIG. 16 illustrates the insertion of the graft vessel preparation device of FIG. 9 onto a anastomosis tool in accordance with one embodiment of the present invention.  
         [0042]    FIG. 17 shows a method for preparing a graft vessel for an anastomosis procedure in accordance with one embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0043]    A graft vessel preparation device and a method for using the graft vessel preparation device is disclosed. As an overview, the present invention relates to a graft vessel preparation device which prepares graft vessels for a vascular anastomosis procedure. During the vascular anastomosis procedure, the graft vessel is grafted to a target vessel, such as a coronary artery. As will be discussed in much greater detail below and with respect to the accompanying Figures, the present invention allows a surgeon to make precise incisions into a graft vessel prior to grafting the vessel to an artery. Moreover, using the graft vessel preparation device, a surgeon may make the incisions to create or define a critical dimension. The critical dimension ensures proper grafting of the graft vessel to the target vessel during the vascular anastomosis procedure. Proper grafting of the graft vessel to the target vessel is ensured since an incision having the critical dimension made in the graft vessel is equivalent to an incision having the critical dimension made in the target vessel.  
         [0044]    Now making reference to the Figures, and more particularly to FIG. 1, FIG. 1 shows a graft vessel preparation device  100  having a graft vessel  112  inserted over spreader arms  108   a  and  108   b  in preparation for grafting. The graft vessel preparation device  100  has a first base plate  102   a , a second base plate  102   b , the spreader arms  108   a  and  108   b , and an extension link  104 . The graft vessel preparation device  100  also includes a first clamp portion  110   a  which is rotatably attached to the first base plate  102   a  and the second base plate  102   b . The graft vessel  112  may be a vessel taken from the body of a patient, such as from the leg of the patient, a synthetic graft, or other graft to be used to bypass an occlusion during a vascular anastomosis procedure. As will be described further with respect to FIGS. 4C and 4D, the graft vessel  112  is grafted to a target vessel  124  of the patient.  
         [0045]    The bases  102   a  and  102   b  include the spreader arms  108   a  and  108   b , the extension link  104  and the first clamp portion  110   a . The spreader arm  108   a  is rigidly attached to the first base plate  102   a  using any technique known in the art, including fasteners and machining such that the first base plate  102   a  and the spreader arm  108   a  form a single unit. The spreader arm  108   b  is rigidly attached to the second base plate  102   b  in the same manner as the spreader arm  108   a  is attached to the first base plate  102   a . The extension link  104  rotatably attaches the first base plate  102   a  to the second base plate  102   b  with fasteners  106 . The fasteners  106  may be any suitable fastener which allows rotatable connection between the extension link  104  and both the first base plate  102   a  and the second base plate  102   b . The first clamp portion  110   a  is rotatably connected to both the first base plate  102   a  and the second base plate  102   b  in the same manner as the extension link  104  is attached to both the first base plate  102   a  and the second base plate  102   b . The base plates  102   a  and  102   b , the extension link  104  and the first clamp portion  110   a  together form a parallelogram linkage. In an alternative embodiment of the present invention, the base plates  102   a  and  102   b  are linkages similar to the extension link  104  such that the linkages, along with the extension link  104  and the first clamp portion  110   a  form a parallelogram linkage.  
         [0046]    In one embodiment of the present invention, the base  102   a  is rigidly attached to a support base  107 . As previously described, the extension link  104  rotatably attaches the base  102   b  to the base  102   a . Therefore, as will be further discussed with reference to FIG. 2, as the extension link  104  rotates, the base  102   b , which is not rigidly attached to the support base  107 , separates from the base  102   a.    
         [0047]    Also shown with respect to FIG. 1 is the angle X 1 . The angle X 1  is the angle which both the first clamp portion  110   a  and the extension link  104  form with respect to the X axis as shown with reference to FIG. 1. As may be seen, the first clamp portion  110   a  and the extension link  104  are substantially parallel with one another such that the angle X 1  of the extension link  104  is substantially the same as the angle X 1  of the first clamp portion  110   a.    
         [0048]    Furthermore, as may be seen with respect to FIG. 1, the spreaders arms  108   a  and  108   b  are adjacent to one another such that they form a single unit. The spreader arms  108   a  and  108   b  are held adjacent to each other to form the single unit with a lock. The lock may be any device suitable for holding the second base plate  102   b  such that the spreaders arms  108   a  and  108   b  form a single unit, such as a clamp or fasteners. In one embodiment of the present invention, a clamp  103  is used to clamp the second base plate  102   b  to form the single unit between the spreader arms  108   a  and  108   b . The clamp  103  includes a grommet  105  which is in contact with the second base plate  102   b  when the graft vessel preparation device  100  is in a locked position. When the clamp  103  releases the second base plate  102   b , the spreader arms  108   a  and  108   b  separate from one another, as shown with reference to FIG. 2.  
         [0049]    FIG. 2 is an embodiment of the present invention where the spreader arms  108   a  and  108   b  have been separated by a tension spring  114 . The tension spring  114  is rigidly attached to the second base plate  102   b  at one end and anchored (not shown) at the end opposite to the end rigidly attached to the second base plate  102   b . The tension spring  114  is rigidly attached to the second base plate  102   b  with any suitable technique known in the art, such as a fastener or a clip. Once the lock is disengaged, the tension spring  114  pulls on the second base plate  102   b  in a downward direction, thereby separating the spreader arms  108   a  and  108   b  from each other.  
         [0050]    A force imparted by the tension spring  114  to separate the spreader arm  108   a  from the spreader arm  108   b  may be selected such that the spreader arms exert a force within the graft vessel  112  in a range preferably between about 40 mm Hg and about 100 mm Hg, and more preferably about 60 mm Hg. This allows the graft vessel  112  to be stretched by the graft preparation device to a condition which accurately mimics the condition of the graft vessel after completion of the anastomosis. In this embodiment, the tension spring  114  has a pretension of about 0.2 lbs., a rate between about 0.1 lb./in. to about 1 lb./in. and a length of about 1 inch.  
         [0051]    As the tensile spring  114  pulls on the second base plate  102   b  to separate the spreader arms  108   a  and  108   b  from each other, the extension link  104  rotates to an angle X 2  with respect to the X axis to separate the first base plate  102   a  from the second base plate  102   b . When the extension link  104  rotates, the spreader arms  108   a  and  108   b  separate from one another since the spreader arms  108   a  and  108   b  are rigidly attached to the base plates  102   a  and  102   b . The tensile spring  114  continues to separate the spreader arms  108   a  and  108   b  from one another until the movement of the spreader arms  108   a  and  108   b  is limited by the fully extended the graft vessel  112 . After the spreader arms  108   a  and  108   b  come into contact with the interior walls of the graft vessel  112  and stretch the graft vessel  112  to the desired amount, a second clamp portion  110   b  is attached to the first clamp portion  110   a , as shown with respect to FIG. 3.  
         [0052]    FIG. 3 shows the second clamp portion  110   b  attached to the first clamp portion  110   a  to trap the graft vessel  112  in a clamp  110 , in accordance with one embodiment of the present invention. The second clamp portion  110   b  attaches to the first clamp portion  110   a  using fasteners  116 . The fasteners  116  may be any suitable type of fastener which securely fastens the second clamp portion  110   b  to the first clamp portion  110   a , such as a threaded fastener or the like. In an alternative embodiment of the present invention, the clamp  110  may have a single-piece hinged design where the clamp  110   a  is rotatably attached with the clamp  110   b  with any suitable technique, such as a hinge or the like. When the second clamp portion  110   b  is attached to the first clamp portion  110   a , the angle X 2  is maintained such that the second clamp portion  110   b  is substantially aligned with the extension link  104 . Once the second clamp portion  110   b  is attached to the first clamp portion  110   a , the graft vessel  112  is trapped by the clamp  110 . When the graft vessel  112  is trapped by the clamp  110 , the graft vessel  112  is ready for incision, or in an alternative embodiment, version. It should be noted that the trapped graft vessel  112  is sufficiently flattened by the clamp  110  to hold the graft vessel  112  in place without damaging the graft vessel  112 .  
         [0053]    Now making reference to FIG. 4A, FIG. 4A illustrates incisors  118   a  and  118   b  slicing the graft vessel  112 , in accordance with one embodiment of the present invention. The incisors  118   a  and  118   b  may be any type of device suitable for slicing a graft vessel, such as a scalpel, a knife, scissors, shears, or the like. The incisors  118   a  and  118   b  begin slicing the graft vessel  112  at incision points  120   a  and  120   b . The incision points  120   a  and  120   b  define a critical dimension Y, as shown more clearly with reference to FIG. 4B.  
         [0054]    FIG. 4B shows the critical dimension Y on the graft vessel  112 , in accordance with one embodiment of the present invention. The critical dimension Y is defined by the incision points  120   a  and  120   b  along the graft vessel  112 . The incision points  112   a  and  112   b  are defined as the points where the first clamp portion  110   a  and the second clamp portion  110   b  intersect with the graft vessel  112 . The defining and maintaining of critical dimension Y with the clamp  110  allows for proper grafting of the graft vessel to a target vessel during the vascular anastomosis procedure. To further illustrate the anastomosis procedure, reference is now made to FIG. 4C.  
         [0055]    FIG. 4C illustrates the insertion of a anastomosis tool  126  having an anvil  128  into a target vessel  124 . In order to graft the graft vessel  112  to the target vessel  124  during the vascular anastomosis procedure, an incision must be made in the target vessel  124  which allows the grafting of the graft vessel  112  to the target vessel  124 . In order to make the incision, the anvil  128  of the anastomosis tool is first inserted into the target vessel  124 . After the anvil  128  is inserted into the target vessel  124  the anvil is lifted in order to stabilize a wall of the target vessel  124  at the anastomosis site, as shown with reference to FIG. 4D.  
         [0056]    FIG. 4D illustrates the stabilization of the target vessel  124  after the anvil  128  is inserted into the target vessel  124 . Once the anvil  128  is lifted to stabilize the target vessel  124 , a critical dimension X is established along the target vessel  124  as shown with reference to FIG. 4D. The critical dimension X corresponds substantially to the length of the anvil  128  along which the graft vessel  112  will be stapled, sutured or otherwise connected. In accordance with one embodiment of the present invention, the critical dimension Y established by the incision points  120   a  and  120   b  is equal or substantially equal to the critical dimension X formed by the anvil  128 . A length on an incision made in the target vessel  124  is substantially the same as the critical dimension X. The incision may be made before or after the graft vessel  112  is connected to the target vessel  124 . Therefore, the formation of the critical dimension Y along the graft vessel  112  ensures that the graft vessel  112  will be properly grafted to the target vessel  124  during the grafting procedure.  
         [0057]    Turning back to FIG. 4A, once the incisors  118   a  and  118   b  are placed at the incision points  120   a  and  120   b , the graft vessel  112  is sliced by the incisors  118   a  and  118   b  in a direction depicted by directional arrows B. As the incisors  118   a  and  118   b  slice the graft vessel  112 , the incisors  118   a  and  118   b  may be guided by grooves  101  in the spreader arms  108   a  and  108   b , as shown with reference to FIG. 4E. It should be noted that the critical dimension Y may also be maintained using other suitable techniques in addition to slicing the graft vessel, such as everting the graft vessel, or the like. In addition, in an alternative embodiment of the present invention, the spreader arms  108   a  and  108   b  may be removed from the graft vessel  112  and the graft vessel  112  may be sliced with scissors or a similar apparatus. In this alternative embodiment, the clamp  110  maintains the critical dimension of the graft vessel  112  as the graft vessel  112  is sliced with scissors starting at the incision points  120   a  and  120   b.    
         [0058]    Now making reference to FIG. 4E, FIG. 4E shows the groove  101  in one of the spreader arms  108   a  or  108   b , in accordance with one embodiment of the present invention. The groove  101  guides the incisor  118   a  as the incisor  118   a  slices the graft vessel  112 . The groove  101  also provides a hard surface for the incisor  118   a  as the incisor  118   a  slices the graft vessel  112 . It should be noted that the spreader arm  108   b  also includes a groove (not shown) which guides the incisor  118   b  as the incisor  118   b  slices the graft vessel  112 .  
         [0059]    Now making reference to FIG. 5, FIG. 5 illustrates removing the graft vessel  112  from the graft vessel preparation device  100 , in accordance with one embodiment of the present invention. Once the incisions are made in the graft vessel  112  with the incisors  118   a  and  118   b , the graft vessel  112  is removed from the graft vessel preparation device  100 . The clamp  110 , which is formed by the first clamp portion  110   a  and the second clamp portion  110   b , is used to hold the graft vessel  112  during removal of the graft vessel  112  from the graft vessel preparation device  100 . The clamp  110  maintains the critical dimension Y of the graft vessel as the clamp  110  is attached to an automated anastomosis tool  132 , as will be described in greater detail with respect to FIG. 7. It should be noted that any device capable of holding the graft vessel  112  may be substituted for the clamp  110 . The clamp  110  is configured to attach to the anastomosis tool  132 , as shown with reference to FIG. 6.  
         [0060]    FIG. 6 is a side view of the clamp  110  which is formed by the first clamp portion  110   a  and the second clamp portion  110   b , in accordance with one embodiment of the present invention. The first clamp portion  110   a  and the second clamp portion  110   b  contain alignment holes  130   a  through  130   d . The alignment holes  130   a  through  130   d  align the clamp  110  with the anastomosis tool  132 . It should be noted that other alignment features may be used to align the clamp  110  with the anastomosis tool  132 , such as a dovetail groove or the like. Also, the alignment holes  130   a  through  130   d  facilitate proper engagement of the clamp  110  with the anastomosis tool  132 , as shown with reference to FIG. 7.  
         [0061]    FIG. 7 illustrates the insertion of the clamp  110  onto the anastomosis tool  132  in accordance with one embodiment of the present invention. The anastomosis tool  132  performs an anastomosis by connecting the graft vessel  112  to the target vessel  124 . One example of an anastomosis tool which may be used is described in U.S. patent application Ser. No. 09/363,255, which is incorporated herein by reference in its entirety. The clamp  110  and the graft vessel  112  must be attached to the anastomosis tool in order to complete the vascular anastomosis procedure. After the graft vessel  112  is sliced and removed from the graft vessel preparation device  100  using the clamp  110 , the clamp  110  is transferred to the anastomosis tool  132  and attached to the anastomosis tool  132  via the alignment holes  130   a  through  130   d . The alignment holes  130   a  through  130   d  fit over corresponding alignment pins  134  of the anastomosis tool  132 . The alignment pins  134  ensure that the graft vessel  112  fits properly within the anastomosis tool  132  in order to allow proper grafting of the graft vessel  112  with the target vessel  124 . The alignment pins  134  are rigidly attached to the anastomosis tool  132  by any suitable means, including pressing or molding the alignment pins  134  with the anastomosis tool  132  from a single material, such as acrylonitrite butadiene styrene (ABS) or polycarbonate; or threaded fasteners or the like. Once the clamp  110  along with the graft vessel  112  is attached to the anastomosis tool  132 , the vascular anastomosis procedure may be performed.  
         [0062]    Now making reference to FIG. 8, FIG. 8 illustrate a method  200  for slicing a graft vessel in preparation for a vascular anastomosis procedure, in accordance with one embodiment of the present invention. In operation  202  of the method  200 , a graft vessel preparation device is locked. When the graft vessel preparation device is locked, spreader arms located on the graft vessel preparation device are adjacent to one another such that a single unit is formed. For example, the graft vessel preparation device  100  shown with respect to FIG. 1 is placed in a locked position such that the spreader arms  108   a  and  108   b  are adjacent to one another to form a single unit. Referring to FIG. 1, the clamp  103  clamps down onto the second base plate  102   b  to lock the graft vessel preparation device  100 . When the clamp  103  clamps the second base plate  102   b , the spreader arms  108   a  and  108   b  are held adjacent to each other to form a single unit. After the graft vessel preparation device  100  is placed in the locked position, an operation  204  is performed.  
         [0063]    In the operation  204 , a graft vessel is placed over the spreader arms of the graft vessel preparation device. The graft vessel is placed over the spreader arms such that the spreader arms occupy an interior of the graft vessel. Referring back to the example and FIG. 1, the graft vessel  112  is placed over the spreader arms  108   a  and  108   b  after the graft vessel preparation device  100  is locked. The graft vessel  112  is placed over the spreader arms  108   a  and  108   b  such that the spreader arms  108   a  and  108   b  occupy an interior of the graft vessel  112 , as shown with respect to FIG. 1. Once the graft vessel  112  is placed over the spreader arms  108   a  and  108   b , an operation  206  is performed.  
         [0064]    In the operation  206 , the spreader arms separate within an interior of the graft vessel. The spreader arms separate within the interior of the graft vessel until the spreader arms stretch the graft vessel. In one embodiment of the present invention, the graft vessel is stretched until a distance between the spreader arms is half the circumference of the graft vessel, such that the graft vessel is stretched flat. As the spreaders arms come into contact with the interior surface of the graft vessel, the spreader arms exert a force on the graft vessel which is equivalent to or less than the force exerted by the blood pressure of blood that normally flows through the graft vessel. Once the spreader arms separate within the graft vessel, the spreader arms may be pushed further into the graft vessel to fully support the end of the graft vessel. In addition, after the spreader arms separate within the graft vessel, the spreader arms may be locked to maintain the proper stretched configuration. Turning back to the example and FIG. 2, the spreader arms  108   a  and  108   b  separate within the interior of the graft vessel  112 . As described earlier, the spreader arms  108   a  and  108   b  separate due to the force applied by the tension spring  114 . The tension spring  114  continues to separate the spreader arms  108   a  and  108   b  within the graft vessel  112  until the spreader arms  108   a  and  108   b  are in contact with interior walls of the graft vessel  112 . Once the spreader arms  108   a  and  108   b  fully separate within the interior of the graft vessel  112  and apply the desired force, the method performs an operation  208 .  
         [0065]    In operation  208 , the graft vessel is secured with a clamp. When the clamp is secured to the graft vessel, incision points on the graft vessel are defined where the graft vessel and the clamp intersect with one another. The incision points define a critical dimension of the graft vessel and where the graft vessel will be sliced, as will be discussed further with reference to operation  210 . Turning back to the example and FIG. 4A, the graft vessel preparation device  100  includes the first clamp portion  110   a  as previously described. Thus, as the graft vessel  112  was placed over the spreader arms  108   a  and  108   b  in the operation  204 , the graft vessel  112  was laid over the first clamp portion  110   a . Therefore, in the operation  208 , the second clamp portion  110   b  is attached to the first clamp portion  110   a  (shown with reference to FIG. 1) with the fasteners  116  to form the clamp  110 . The intersection of the clamp  110  and the graft vessel  112  define the incision points  120   a  and  120   b  where the graft vessel is to be sliced in the operation  210 .  
         [0066]    Prior to slicing the graft vessel in the operation  210 , the spreader arms are mounted further within the interior of the graft vessel. The spreader arms are pushed within the graft vessel in order to assist the incisors in the slicing operation. In this embodiment, the spreader arms contain grooves which provide a surface for the incisors as the incisors slice graft vessel. Moreover, the groove provides a track which facilitates the slicing of the graft vessel during the slicing operation described with respect to the operation  210 .  
         [0067]    In the operation  210 , the graft vessel is sliced after the graft vessel is secured with the clamp in the operation  208 . Referring back to FIG. 4A and the example, the incisors  118   a  and  118   b  slice the graft vessel  112  from the incision points  120   a  and  120   b  outward to an end of the graft vessel  112 . As described earlier, the incision made in the graft vessel  112  is made such that the graft vessel  112  may be properly grafted to the target vessel  124  during the vascular anastomosis procedure; Once the graft vessel  112  is sliced in the operation  210 , the graft vessel  112  and the clamp  110  are removed from the graft vessel preparation device  100  in operation  212 . The graft vessel  112  and the clamp  110  are removed from the graft vessel preparation device  100  by disengaging the clamp  110  from the graft preparation device  100  and sliding the graft vessel  112  off of the spreader arms  108   a  and  108   b . After the operation  212  is complete, the graft vessel  212  is ready for grafting to a target vessel during the vascular anastomosis procedure.  
         [0068]    Now making reference to FIG. 9, FIG. 9 illustrates a graft vessel preparation device or flapper  148  in accordance with an alternative embodiment of the present invention. In this embodiment, the graft vessel flapper includes a locator clamp  150  having alignment holes  146  and a spreader  136 . The alignment holes  146  align the locator clamp  150  with the anastomosis tool  132 . In addition, the alignment holes  146  facilitate proper engagement of the graft vessel flapper  148  with the anastomosis tool  132 , as will be further discussed with reference to FIG. 16. The locator clamp  150  establishes the critical dimension Y (not shown) of the graft vessel  112 , as will be further discussed with reference to FIGS. 12 through 14B. The spreader  136  includes a first spreader arm  136   a  and a second spreader arm  136   b , as more clearly shown with reference to FIG. 10A.  
         [0069]    FIG. 10A shows the spreader  136 , in accordance with one embodiment of the present invention. The spreader  136  includes the first spreader arm  136   a  and the second spreader arm  136   b  which are movable with respect to one another. The spreader arms  136   a  and  136   b  are moved with respect to one another by a spring  138 . The spring  138  is a torsion spring in one embodiment of the present invention which connects the first spreader arm  136   a  to the second spreader arm  136   b . The spring  138  attaches to a distal end of the first spreader arm  136   a  and a distal end of the second spreader arm  136   b . The spring  138  may be any suitable type of spring which separates the first spreader arm  136   a  from the second spreader arm  136   b , such as a torsion spring, a leaf spring, a compression spring, an elastomer having spring-like characteristics, or the like. In one embodiment of the present invention. The spring  138  is a torsion spring having a spring rate in preferably in a range between about 0.001 lbs./deg. to about 0.01 lbs./deg. and more preferably about 0.00156 lbs./deg. The first spreader arm  136   a  and the second spreader arm  136   b  are configured to receive the graft vessel  112  when the spreader  136  is in a locked position, as shown with reference to FIG. 10B.  
         [0070]    FIG. 10B illustrates the spreader  136  in a locked or closed position, in accordance with another embodiment of the present invention. The spreader  136  is locked when an end  136   a - 1  of the first spreader arm  136   a  makes contact or is positioned substantially adjacent to an end  136   b - 1  of the second spreader arm  136   b , as shown with reference to FIG. 10B. The spreader  136  is placed into the locked position using any suitable technique, such as a clip, a clamp or the like. When the spreader arms  136   a  and  136   b  are placed in the locked position, the spreader  136  receives the graft vessel  112 , as shown with reference to FIG. 11.  
         [0071]    FIG. 11 shows the graft vessel  112  placed over the spreader  136 , in accordance with one embodiment of the present invention. Once the graft vessel  112  is placed over the spreader  136 , the first spreader arm  136   a  and the second spreader arm  136   b  separate within an interior of the graft vessel  112 . The spreader arms  136   a  and  136   b  separate by the action of the spring  138 . The first spreader arm  136   a  and the second spreader arm  136   b  separate until the first spreader arm  136   a  and the second spreader arm  136   b  are adjacent interior walls of the graft vessel  112  and stretch the graft vessel  112  a desired amount which simulates the condition of the graft vessel when implanted in the body.  
         [0072]    Turning back to the graft vessel flapper  148  shown with respect to FIG. 9, the graft vessel flapper also includes the locator clamp  150 . The locator clamp  150  includes a critical dimension locator  140 , as more clearly shown with reference to FIG. 12. The critical dimension locator  140  has a raised portion  140   a , a base  140   b  and threaded fasteners  140   c . The raised portion  140   a  is rigidly attached to the base  140   b  and may be formed into the base  140   b  using any suitable techniques, such as spot welding, injection molding, or the like. In the embodiment shown with respect to FIG. 12, the raised portion  140   a  is in a triangular configuration. However, it should be noted that the raised portion  140   a  may have any orientation which allows for the establishment of a critical dimension Y for the graft vessel  112 , as will be more fully discussed with reference to FIG. 13A. It should also be noted that in an alternative embodiment of the present invention, the raised portion  140   a  is not rigidly attached to the critical dimension locator  140 . Thus, as will be more fully discussed with reference to FIG. 13A, once a graft vessel is placed on the critical dimension locator  140 , the raised portion  140   a  may also be coupled with the critical dimension locator  140 . The threaded fastener  140   c  allows connection between the critical dimension locator  140  and a second clamp half  142  (not shown). The threaded fastener  140   c  may be any type of fastener suitable for connecting the critical dimension locator  140  with the second clamp half  142 . Also, the threaded fastener  140   c  has an edge  140   c - 1  and the raised portion  140   a  includes an edge  140   a - 1 . The raised portion  140   a , along with the threaded fastener  140   c , establishes a critical dimension Y for the graft vessel  112  defined between the edges  140   a - 1  and  140   c - 1 , as shown with reference to FIGS. 13A and 13B.  
         [0073]    FIG. 13A is an embodiment of the present invention showing the spreader  136 , along with the graft  112 , engaged with the critical dimension locator  140 . After the first spreader arm  136   a  and the second spreader arm  136   b  separate within the interior of the graft vessel  112 , the spreader  136 , along with the graft vessel  112 , is placed on to the critical dimension locator  140  in order to establish the critical dimension Y. Initially, the spreader  136  and the graft vessel  112  are placed in the critical dimension locator  140  such that the graft vessel  112  resides between the edges  140   a - 1  and  140   c - 1 . After the spreader  136  and the graft vessel  112  are placed within the critical dimension locator  140 , the spreader  136  and the graft vessel  112  are rotated in a clockwise direction Z on the critical dimension locator  140 , as shown with respect to FIG. 13B.  
         [0074]    FIG. 13B shows the spreader  136 , along with the graft vessel  112 , rotated clockwise within the critical dimension locator  140  in order to establish the critical dimension Y, in accordance with one embodiment of the present invention. The spreader  136  and the graft vessel  112  are rotated until the graft vessel  112  comes into contact with the edges  140   a - 1  and  140   c - 1  at contact points  120   a  and  120   b , as shown with reference to FIG. 13B. As previously described, the contact points  120   a  and  120   b  are the endpoints for the critical dimension Y. In addition, as previously discussed, the critical dimension Y allows for proper grafting of the graft vessel to a target vessel during a vascular anastomosis procedure. Once the critical dimension Y is established on the graft vessel  112 , the second clamp half  142  is attached to the critical dimension locator  140 .  
         [0075]    The second clamp half  142  is more clearly shown with reference to FIG. 14A. The second half clamp  142  includes through holes  142   a  and a recess  142   b . The through holes  142   a  allow for passage of the threaded fasteners  140   c  of the critical dimension locator  140  through the second half clamp  142  such that the second clamp half  142  may attach to the critical dimension locator  140 . The recess  142   b  allows the raised portion  140   a  to fit within the second half clamp  142  when the second clamp half  142  is attached to the critical dimension locator  140 , as shown with reference to FIG. 9.  
         [0076]    In this embodiment of the present invention, the recess  142   b  has a triangular configuration as shown with respect to FIG. 14B such that the critical dimension locator  140  will fit flush with the second half clamp  142 . It should be noted that the configuration of the recess  142   b  complements the configuration of the raised portion  140   a . Thus, if in an alternative embodiment of the present invention, the raised portion  140   a  contains a square configuration, the recess  142   b  will also have a square configuration.  
         [0077]    Returning to FIG. 9 and the graft vessel flapper  148 , once the critical dimension Y is established on the graft vessel  112 , the second clamp half  142  is securely attached to the critical dimension locator  140  to form the locator clamp  150 . The second clamp half  142  is securely attached to the critical dimension locator  140  by passing the threaded fasteners  140   a  through the through holes  142   a  of the second clamp half  142 . A fastener  140   d  is then fixed to the threaded fasteners  140   c . In one embodiment of the present invention, the fastener  140   d  may be any suitable type of fastener which securely attaches the second clamp half  142  to the critical dimension locator  140 , such as a threaded nut or the like. Once the locator clamp  150  traps and secures the graft vessel  112  in place, the graft vessel  112  is sliced, as shown with reference to FIG. 15.  
         [0078]    FIG. 15 shows the graft vessel  112  being sliced with the incisors  118   a  and  118   b , in accordance with one embodiment of the present invention. The incisors  118   a  and  118   b  slice the graft vessel  112  from the incision points  120   a  and  120   b  outward to an end of the graft vessel  112  in order to maintain the critical dimension Y. It should also be noted that in an alternative embodiment of the present invention, the incisors  118   a  and  118   b  may slice the graft vessel  112  at any point, as long as the critical dimension Y is maintained. For example, the incisors  118   a  and  118   b  may slice the graft vessel  112  at the points  121   a  and  121   b , which, as may be seen with reference to FIG. 15, maintain the critical dimension Y. As described earlier, the incisors  118   a  and  118   b  may be any type of cutting device suitable for slicing graft vessels, such as a scalpel, a pair of scissors or the like. Once the graft vessel  112  is sliced, the graft vessel flapper  148  is attached to the anastomosis tool  132  in preparation for grafting during the vascular anastomosis procedure, as shown with reference to FIG. 16.  
         [0079]    FIG. 16 illustrates the insertion of the graft vessel flapper  148  onto the anastomosis tool  132 , in accordance with one embodiment of the present invention. As previously mentioned, the anastomosis tool  132  grafts the graft vessel  112  to the target vessel  124  during the vascular anastomosis procedure. The vascular anastomosis procedure is performed using the anastomosis tool  132 . Thus, the graft vessel flapper  148  and the graft vessel  112  must be attached to the anastomosis tool  132  in order to complete the vascular anastomosis procedure. The graft vessel flapper  148  is attached to the anastomosis tool  132  via the alignment holes  146 . The alignment holes  146  fit over the alignment pins  134  in order to ensure proper fitment of the graft vessel flapper  148  with the anastomosis tool  132 . As described earlier, proper fitting of the graft vessel flapper  148  with the anastomosis tool  132  is necessary for proper grafting of the graft vessel  112  to the target vessel  124  during the vascular anastomosis procedure. Once the graft vessel flapper  148  and the graft vessel  112  are attached to the anastomosis tool  132 , the vascular anastomosis procedure is performed.  
         [0080]    Now making reference to FIG. 17 and a method  300 , FIG. 17 shows the method  300  for preparing a graft vessel for an anastomosis procedure in accordance with one embodiment of the present invention. In the method  300 , an operation  302  is first performed where a spreader is locked. The spreader is locked in order to allow the placement of a graft vessel over the spreader. For example, turning to FIG. 10B, the spreader  136  is placed in a locked position. As described earlier, the spreader  136  may be locked using any suitable technique, including a clamp, a clip, or simply pinching closed the spreader with a user&#39;s fingers such that spreader arms of the spreader are held together. As may be seen with respect to FIG. 10B, the spreader  136  is locked such that the first spreader arm  136   a  contacts the second spreader arm  136   b  at the ends  136   a - 1  and  136   b - 1 . When the spreader  136  is placed in the locked position, the spreader  136  is configured to receive a graft vessel, as described with respect to an operation  304 .  
         [0081]    The operation  304  in FIG. 17 is performed once the spreader is locked. In the operation  304 , a graft vessel is placed over the spreader while the spreader is in the locked position. After the graft vessel is placed over the spreader in the operation  304 , the spreader arms of the spreader are separated within an interior of the graft vessel in the operation  306 . Turning back to the example and FIG. 11, once the graft vessel  112  is placed over the spreader  136  in the operation  304 , the first spreader arm  136   a  and the second spreader arm  136   b  separate from each other within the interior of the graft vessel  112 . The spring  138  separates the first spreader arm  136   a  from the second spreader arm  136   b . The first spreader arm  136   a  and the second spreader arm  136   b  continue to separate from one another until both the spreader arms  136   a  and  136   b  come into contact with an interior surface of the graft vessel  112 . Once the first spreader arm  136   a  and the second spreader arm  136   b  separate within the graft vessel  112  in the operation  306 , an operation  308  is performed.  
         [0082]    In the operation  308 , the spreader, along with the graft vessel, is placed onto a graft vessel flapper. As described earlier with reference to the graft vessel flapper  148 , the graft vessel flapper establishes a critical dimension on the graft vessel. Turning back to the example and FIG. 13A, the critical dimension locator  140  forms part of the graft vessel flapper  148 . As such, the spreader  136  and the graft vessel  112  are placed in the critical dimension locator  140 . After the spreader  136  is placed in the critical dimension locator  140 , an operation  310  is performed.  
         [0083]    In the operation  310 , the spreader and the graft vessel are rotated within the graft vessel flapper. The spreader is rotated until the graft vessel comes into contact with edges of the graft vessel flapper. The edges of the graft vessel flapper establish the endpoints of the critical dimension when the graft vessel contacts the edges, thereby establishing the critical dimension on the graft vessel. Referring back to the example and FIG. 13A, the spreader  136  and the graft vessel  112  are rotated in the clockwise direction Z until the graft vessel  112  comes into contact with the edges  140   a - 1  and  140   c - 1  of the critical dimension locator  140 , as shown with reference to FIG. 13B. The graft vessel  112  contacts the edges  140   a - 1  and  140   c - 1  at the endpoints  120   a  and  120   b . As previously described, the endpoints  120   a  and  120   b  establish the critical dimension Y. Once the critical dimension Y is established in the operation  310 , the graft vessel  112  is trapped in operation  311 .  
         [0084]    The graft vessel  112  is trapped in the operation  311  as a second clamp half is attached to graft vessel flapper. When the second half clamp is attached to the graft vessel flapper, the graft vessel flapper holds the critical dimension Y. Turning back to the example and FIG. 15, the second clamp half  142  is attached to the graft vessel flapper  148 . When the second clamp half  142  is attached to the graft vessel flapper  148  when the threaded fasteners  140   c  pass through the through holes  142   a  and secured with the fasteners  140   d . Once the graft vessel  112  is trapped in the graft vessel flapper  148 , the graft vessel  112  is sliced in an operation  312 .  
         [0085]    Once the graft vessel is sliced in the operation  312 , the graft vessel flapper is attached to a anastomosis tool in the operation  314 . As described earlier, the anastomosis tool facilitates grafting of the graft vessel to a target vessel during a vascular anastomosis procedure. Making reference to the example and FIG. 16, the graft vessel  112  is first sliced in the operation  312  and then attached to the anastomosis tool  132 . As discussed earlier, the graft vessel flapper  148  attaches to the anastomosis tool  132  via the alignment holes  146  and alignment pins  134 . Once the graft vessel flapper  148  and the graft vessel  112  are attached to the anastomosis tool  132 , the graft vessel  112  is grafted to the target vessel  124  during the vascular anastomosis procedure. This grafting may be performed by any method suitable for grafting a graft vessel to a target vessel, such as suturing, stapling, tissue welding, clamping or the like.  
         [0086]    The present invention now offers surgeons an automated method for accurately grafting a graft vessel to a target vessel. The prior art problems of dealing with the innate flexing tendencies of the graft vessel due to the small size and the flexible, circular configuration of the of the graft vessel are obviated with the present invention. Moreover, the graft vessel preparation device accurately and precisely allows the graft vessel to be a cut in a manner which allows a perimeter of the graft vessel end to be matched to a perimeter of an anastomosis site on a target vessel. Thus, the surgeon saves the time required to accurately and precisely slice the graft vessel, thereby decreasing the overall time a patient spends in surgery and decreasing the overall costs associated with spending time in surgery.  
         [0087]    Furthermore, as discussed earlier, when a surgeon grafts a graft vessel to a target vessel, an assistant may be required to hold the edges of the graft vessel and assist in preparing the graft vessel for the anastomosis procedure. The clamp of the present invention holds the graft vessel as the graft vessel is placed in the anastomosis tool. The clamp of the present invention also holds the graft vessel during the anastomosis procedure. As such, the need for an assistant to hold the graft vessel during grafting is avoided with the present invention, thereby further reducing the time and the overall costs associated with performing a grafting procedure on a patient.  
         [0088]    The above are exemplary modes of carrying out the invention and are not intended to be limiting. It will be apparent to those of ordinary skill in the art that modifications thereto can be made without departure from the spirit and scope of the invention as set forth in the following claims.