Abstract:
A device prepares leaflets for cardiovascular valve reconstruction from a pericardial tissue sheet harvested from a patient. A cutter is adapted to cut a predetermined pattern having a selected leaflet size. A tissue marker automatically aligned with the predetermined cutting pattern is configured to mark suture positions on the leaflet in response to placement of the cutter. Cutting of a leaflet from the tissue sheet and marking of suture positions on the leaflet are obtained concurrently. A set of such devices spanning a variety of leaflet sizes may be provided in a kit that results in an ability to quickly obtain a properly sized and marked leaflet for reconstruction.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. provisional application 62/342,483, filed on May 27, 2016, which is incorporated herein by reference in its entirety. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
       [0002]    Not Applicable. 
       BACKGROUND OF THE INVENTION 
       [0003]    The present invention relates in general to marking and cutting a heart valve leaflet from a pericardium membrane for use in valve repair/reconstruction, and, more specifically, to devices and systems for simultaneously marking and cutting a valve leaflet with improved accuracy and shortened operating times. 
         [0004]    One type of heart surgery relates to heart valve repair or replacement. For a patient with a damaged valve leaflet (e.g., in a bicuspid or tricuspid valve), there is a surgical technique for repairing the valve leaflet using the patient&#39;s own pericardium tissue, bovine tissue, or a synthetic material. A manmade synthetic valve has good durability but requires continuous use of an anti-coagulate drug. A valve leaflet reconstruction operation using pericardium tissue removed from the patient is becoming a preferred technique. A thin sheet of pericardium tissue harvested from the patent must be cut and shaped according to the required size of the replaced leaflet. The cut leaflet is then sewn into the original position of the diseased leaflet. This therapy appears to have longer life compared to a bovine tissue valve, and it is generally safe from rejection since this therapy uses the patient&#39;s own tissue. 
         [0005]    More specifically, the procedure for valve leaflet repair may include the following steps. Circulatory support incisions are made and a perfusion system (i.e., heart lung machine) is connected. The target heart valve (e.g., aortic valve) is then exposed. A thin sheet of pericardium tissue is excised and prepared by treatment with known chemicals. The damaged valve leaflet is trimmed away. A sizing tool is used in order to measure the site (e.g., valve width) to which the new leaflet will be attached. The processed pericardium tissue is placed on a backing plate. Using a template corresponding to the measured size and a marking pen, the desired size and shape for a replacement leaflet is stenciled onto the tissue sheet. The locations (e.g. up to 15 dots) for forming individual sutures may also be marked. Using scissors, the stenciled leaflet is manually cut and trimmed from the tissue sheet. The leaflet is sutured onto the valve annulus and the leaflet commissures are sutured. 
         [0006]    During the time that the cut and trim tasks are performed, the heart is stopped and the patient is supported by external circulation using oxygenator and blood pump. This has unfavorable effects on the body, so the duration needs to be minimized. Thus, it would be desirable to minimize valve leaflet preparation time while obtaining more accurately shaped leaflets, thereby contributing to better outcomes of the therapy. 
       SUMMARY OF THE INVENTION 
       [0007]    The invention introduces various devices wherein each device is itself capable of both cutting a desired leaflet size and marking suturing locations in one user action. In one example, a device for preparing leaflets for cardiovascular valve reconstruction resembles a stamper or embosser with a “cookie cutter” blade. The device combines a cutting edge with a tissue marker, wherein cutting of a leaflet from a membrane is obtained simultaneously with marking suture positions on the leaflet. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIGS. 1-3  are perspective views of a cutting/marking device according to a first embodiment of the invention. 
           [0009]      FIG. 4  is an exploded view of the device of  FIG. 1 . 
           [0010]      FIG. 5  is an exploded view of the base plate and ink applicators. 
           [0011]      FIG. 6  is a partial cross-sectional view of the base plate and ink applicators. 
           [0012]      FIG. 7  is a cross-sectional view showing the mounting of the plunger and the base plate in greater detail. 
           [0013]      FIGS. 8A, 8B, and 8C  show a sequence of concurrently cutting and marking a leaflet using the device of  FIG. 1 . 
           [0014]      FIG. 9  is a cross section showing an alternative embodiment of a cutting/marking device. 
           [0015]      FIG. 10  is a perspective view of another embodiment including a cutting and marking stencil. 
           [0016]      FIG. 11  is a perspective view of another embodiment including a motion control table. 
           [0017]      FIG. 12  is a perspective view of another embodiment including a laser marking and cutting system. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0018]    A first embodiment of a “cookie cutter” type of leaflet cutting and marking device  10  is shown in  FIGS. 1-7 . Referring to  FIGS. 1-3 , a base plate  11  provides a frame for supporting a cutting blade  12  on a bottom side. Preferably, base plate  11  generally conforms to and is slightly larger than a desired leaflet profile. Cutting blade  12  provides a cutting edge following a precisely configured cutting pattern according to a selected leaflet dimension. The particular size for which device  10  is configured may preferably be labeled on the device so that a kit having a plurality of differently sized cutting devices can be bundled to support a surgical procedure. Base plate  11  has an upper cavity receiving a plunger  13  which is slidably mounted for upward and downward movement within the upper cavity of base plate  11 . Base plate  11  has a bottom wall  14  with appropriately placed apertures receiving a plurality of ink applicators  15  which are extendable under control of plunger  13 . 
         [0019]    Referring to  FIG. 4 , base plate  11  includes a bottom groove  25  which fixedly mounts cutting blade  12 . Bottom wall  14  of base plate  11  includes a plurality of apertures  20  each arranged to receive a respective one of ink applicators  15 . Each ink applicator  15  includes a spring-loaded base  21 , pen body  22 , and marking tip  23 . Apertures  24  are sized to accommodate pen bodies  22 . Spring bases  21  are arranged to abut a thrust surface  30  on plunger  13 . A bias member (e.g., spring)  26  is disposed between wall  14  and thrust surface  30  in order to urge surface  30  into an upward position wherein applicator tips  23  are retracted to a position farthest away from the cutting side. Plunger  13  may preferably include a rigid top section  16  and a resilient bottom section or layer  17 . Resilient section  17  cushions the interface with ink applicators  15  and may be comprised of a rubber sheet. Rigid top section  16  is integrally formed with a mounting shaft  18  extending toward a bore  20  in wall  14 . Latching tabs  19  on a bottom end of shaft  18  may interlock with the latching surface in bore  20 . 
         [0020]    Referring to  FIG. 5 , upper cavity  26  of base plate  11  receives ink applicators  15 . Each aperture  24  includes a shoulder  27  to retain spring bases  21  of ink applicators  15  within cavity  26  by interference between spring bases  21  and shoulders  27 . A collar  28  is adapted to align and retain one end of spring  26  and to provide an internal latching surface  29  for receiving latching tabs  19  as shown in  FIG. 6 . The arrangement for slidably retaining plunger  13  in alignment with collar  28  is shown in greater detail in  FIG. 7 . 
         [0021]    Preparation of a leaflet using the present invention is shown in  FIGS. 8A-8C . In  FIG. 8A , a pericardial membrane sheet  35  is first prepared and a surgeon measures a patient&#39;s aortic structures to determine a desired leaflet size. A device  10  matching the measured dimensions for the desired leaflet size is selected and brought into contact with sheet  35 . As shown in  FIG. 8B , sheet  35  and device  10  are preferably arranged on top of a rigid backing plate  86 . By manually applying a pressing force  37  onto base plate  11  (i.e., without applying pressure to plunger  13 ), cutting blade  12  penetrates sheet  35  thereby quickly and precisely cutting a leaflet of the desired dimensions. Without removing device  10 , marking of the corresponding suture positions is concurrently performed as shown in  FIG. 8C  using a downward pressing force  38  against plunger  13 . As a result, the ink applicators are moved against the spring bias forces (created by the main bias member and the individual ink applicator spring bases) until contacting the cut leaflet and marking the desired suture positions defined by the placement of the ink applicators. 
         [0022]    As shown in  FIG. 9 , a plunger  40  may have a top section  41  and resilient bottom layer  42 . In order to improve alignment of ink applicators  15 , a socket  43  may be formed as a depression or hole within layer  42  having a diameter to receive one end of a respective ink applicator. 
         [0023]    In an embodiment shown in  FIG. 10 , a support plate  50  receives a pericardial sheet or membrane  51  harvested from a patient. A stencil plate  52  (e.g., comprised of a thin, biocompatible metal plate) has a series of grooves or slots  53  following an outline of a leaflet of a predetermined size. A surgical setting would be equipped with a plurality of stencil plates configured for a variety of leaflet sizes so that one matching a measured dimension can be selected. Stencil plate  52  further includes a series of marking holes  54  penetrating stencil plate  52  and having a diameter sufficient to accommodate a marking pen  55 . Grooves  53  have a width adapted to accommodate a cutting blade  56  of a cutting tool  57 . Blade  56  is mounted to a handle  58  so that an outline of a desired leaflet can be manually cut while pressing stencil plate  52  against sheet  51 . Connecting bridges  60  may be needed which interrupt grooves  53 , but corresponding cuts beneath bridges  60  can be easily made in sheet  51  after removing stencil plate  52 . In an alternative embodiment, grooves and marking holes for differently sized leaflets can be provided on a single stencil plate provided that the included features (i.e., edges and holes) do not overlap. 
         [0024]    In an embodiment in  FIG. 11 , a support plate  65  receives a pericardial sheet or membrane  66  harvested from a patient. An X-Y motion control mechanism  67  is provided having a carriage  68  supporting a cutting blade  70  and a marking pen  71  which are vertically extendable from carriage  68  in response to a programmable controller (not shown). Carriage  68  is slidably mounted on a movable arm  72  such that servo mechanisms can translate the position of blade  70  and pen  71  to follow any desired pattern to create (i.e., cut and mark) a desired leaflet. Pen  71  may be comprised of an ink jet head connected to an ink reservoir  73  by a conduit  74 . The controller may include a library of pre-defined patterns according to a variety of desirable leaflet shapes and sizes to be selected according to the needs of a particular patient. 
         [0025]    In an embodiment in  FIG. 12 , a support plate  80  receives a pericardial sheet or membrane  81  harvested from a patient. Cutting and marking to form a desired leaflet from sheet  81  is performed using a laser scanning device  82  connected by a laser fiber  83  to a laser power unit (LPU)  84  (e.g., an Nd-YAG laser). Scanning device  82  may comprise a polygon mirror unit  85  with motion control to scan a laser beam  86  according to pre-programmed patterns for different sizes of leaflets. LPU  84  provides two different power levels, wherein a higher power level is used while scanning a leaflet edge in order to cut (i.e., ablate) the leaflet and a lower power level (reduced amplitude or shortened time pulse) is used while positioning laser beam  86  at the locations of the suture markers in order to create a visible surface burn without significant penetration. In an alternate embodiment, the laser projection lens could be mounted on an X-Y motion control mechanism of the type shown in  FIG. 11  in order to scan the laser beam along the desired paths.