Abstract:
A heart valve prostheses crimping apparatus and method for deducing the diameter of stents containing heart valve prosthesis. A medical prosthesis catheter loading apparatus, including a crimping assembly for reducing the diameter of a prosthesis; and a catheter clamp for holding a catheter adjacent to the prosthesis. Also disclosed is an apparatus for reducing the diameter of a medical prosthesis, including a base, a crimp head connectable to the base, and an actuation mechanism connected to the base and connectable to the crimp head to actuate the crimp head. Also disclosed is a method of loading a medical prosthesis into a catheter, including the steps of reducing the diameter of a prosthesis from its normal deployed state to a diameter less than that of the lumen of the catheter; holding a catheter adjacent to the reduced diameter prosthesis; and moving the prosthesis into the catheter lumen.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS, IF ANY  
       [0001]     This application claims the benefit under 35 U.S.C. §119(e) of co-pending U.S. Provisional Patent Application Ser. No. 60/580,244, filed Jun. 16, 2004, which is/are hereby incorporated by reference. 
     
    
       [0002]     A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the US Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.  
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0003]     Not applicable.  
       REFERENCE TO A MICROFICHE APPENDIX, IF ANY  
       [0004]     Not applicable.  
       BACKGROUND  
       [0005]     1. Field  
         [0006]     The present invention relates, generally, to medical devices and methods. Particularly, the invention relates to tissue prostheses processing apparatus and methods of making and using tissue prostheses apparatus and systems to process tissue prostheses. More particularly, the invention relates to apparatus and methods for reducing the diameter of tissue prostheses such as heart valves. Most particularly, the invention relates to a heart valve prostheses crimping apparatus and method whereby the diameter of stents containing heart valve prostheses is reduced.  
         [0007]     2. Background Information  
         [0008]     The state of the art includes stent crimping and balloon folding apparatus and methods produced by applicant&#39;s assignee, Machine Solutions, Inc. of Flagstaff, Ariz., USA.  
         [0009]     A need is believed to exist for the present invention.  
         [0010]     All US patents and patent applications, and all other published documents mentioned anywhere in this application are incorporated by reference in their entirety.  
       BRIEF SUMMARY  
       [0011]     The invention provides a heart valve prostheses crimping apparatus and method which are practical, reliable, accurate and efficient, and which are believed to fulfil the need and to constitute an improvement over the background technology.  
         [0012]     In one aspect, the invention provides a medical prosthesis catheter loading apparatus, comprising a crimping assembly for reducing the diameter of a prosthesis; and a catheter clamp for holding a catheter adjacent to the prosthesis.  
         [0013]     In another aspect, the invention provides an apparatus for reducing the diameter of a medical prosthesis, comprising a base, a crimp head connectable to the base, and an actuation mechanism connected to the base and connectable to the crimp head to actuate the crimp head.  
         [0014]     In a further aspect, the invention provides a method of loading a medical prosthesis into a catheter, comprising the steps of reducing the diameter of a prosthesis from its normal deployed state to a diameter less than that of the lumen of the catheter; holding a catheter adjacent to the reduced diameter prosthesis; and moving the prosthesis into the catheter lumen.  
         [0015]     The features, benefits and objects of the invention will become clear to those skilled in the art by reference to the following description, claim(s), if any, and drawings. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0016]     The present invention, and the manner and process of making and using it, will be better understood by those skilled in the art by reference to the following drawings.  
         [0017]      FIG. 1  is a perspective view of one embodiment of the tissue prostheses processing apparatus of the present invention.  
         [0018]      FIG. 2  is a further perspective view of the apparatus.  
         [0019]      FIG. 3  illustrates embodiments of the tub, catheter clamp and crimping assemblies of the apparatus.  
         [0020]      FIG. 4  is an exploded view of the crimping assembly of the apparatus.  
         [0021]      FIG. 5  is a perspective view of the crimping assembly.  
         [0022]      FIG. 6  is a perspective view of the crimping assembly showing an embodiment of the activation ring.  
         [0023]      FIG. 7  is a perspective view of the back side of an embodiment of the stationary plate of the crimping assembly.  
         [0024]      FIG. 8  is a perspective view of the back side of an embodiment of the main face plate of the crimping assembly.  
         [0025]      FIG. 9  is an exploded view of an embodiment of the quick change catheter clamp of the apparatus.  
         [0026]      FIGS. 10-15  illustrate a process of using the quick change catheter clamp.  
         [0027]      FIG. 16  is a perspective view of an alternative embodiment of the crimping assembly of the apparatus.  
         [0028]      FIG. 17  is a front elevation view of the crimping assembly of  FIG. 16 .  
         [0029]      FIG. 18  is a top plan view thereof.  
         [0030]      FIG. 19  is an end view thereof.  
         [0031]      FIG. 20A  is another perspective view of the crimping assembly, showing element loading of a fresh set of elements using a loader.  
         [0032]      FIG. 20B  is an exploded view of the crimping assembly.  
         [0033]      FIG. 21A -B illustrate an embodiment of the activation ring of the crimping assembly.  
         [0034]      FIG. 22  is a perspective view of an embodiment of the disposable crimping head of the crimping assembly, also showing the loader.  
         [0035]      FIG. 23  is an exploded view of the crimping head, also showing the loader.  
         [0036]      FIG. 24  is a perspective view of embodiments of the base and plates of the crimping assembly.  
         [0037]      FIG. 25  is a front elevation view of the crimp head.  
         [0038]      FIG. 26  is a perspective view of an embodiment of a crimping element or segment of the crimping head shown in  FIGS. 4 and 6 .  
         [0039]      FIG. 27  is a perspective view of an alternative embodiment of a crimping element for use with the crimping head shown in  FIGS. 16-25 .  
         [0040]      FIG. 28  is a view showing the opposite sides in phantom.  
         [0041]      FIG. 29  is a view of the lateral side of the segment.  
         [0042]      FIG. 30  is a view of the longitudinal side of the segment.  
         [0043]      FIG. 31  is a view of the distal end of the segment. 
     
    
     DETAILED DESCRIPTION  
       [0044]     The tissue prosthesis crimping apparatus of the present invention is useable by a single operator to easily reduce the diameter of, or crimp, relatively large stents containing tissue prostheses such as heart valves and the like, and loads such device into a catheter for later use and deployment in a patient. It is suitable “bed-side” catheter procedures such as minimally invasive heart valve replacement (MIHVR). The tissue prosthesis crimping apparatus is also useable for bench testing medical devices and product testing such devices with animals.  
         [0045]     Referring first to  FIGS. 1-3 , the tissue prosthesis crimping apparatus  10  for loading a prosthesis or other medical device (not shown) into a catheter or sheath  11 , or other tubular structure comprises, in general, a crimping assembly  12 , a submersion tank or tub  13  for holding a medical solution  14  such as saline, and catheter clamp  15 . The apparatus  10  operates while partially submerged in the saline solution  14  which is contained in the removable tub  13 . Tank  13  is preferably about 13×7.5 inches, with a height of about 5.25 inches, a maximum liquid volume of about 5.15 liters and a filled weight of about 15 lbs. Only a single person is required to perform all operations of the apparatus. A base or frame portion  19  of the crimping assembly and the catheter clamp  15  are reusable and can be steam and EtO sterilized. All parts in direct contact with the stent or prosthesis, including the crimping elements or segments (described below) of a crimp head or assembly  20 , are one-use disposable pieces that are easily interchanged between procedures.  
         [0046]     In general, operation of the system  10  first involves placing new crimp elements or segments into the crimp head  20  (preferably with the assistance of a loader), and moving it to a full open position. Next, the machine base  19 , including the head  20 , is placed into the tub  13 . The catheter  11  is secured to the quick release clamp  15 . The clamp  15  is secured to the base  19 . Next, a prosthesis mated with a stent is inserted into the head  20  for example by hand, and the head  20  is actuated, which closes a central aperture thereof, until the individual crimp elements rest against hard stops. This radially compresses or crimps the stent/prosthesis. The crimped device is pushed (for example via a quill) or pulled (via a device internal to the catheter) into the catheter  11 . This apparatus is useable with both balloon expandable and self expanding prosthesis stents. The catheter clamp  15  is removed from the base  19 . Finally, the catheter  11  is removed from the clamp  15  with the crimped prosthetic device, for example a heat valve, installed therein.  
         [0047]     Referring also to  FIGS. 4-6 , the crimping assembly  12  comprises the base or frame  19 , the crimp head  20 , and an actuation mechanism  21  connected to the frame and connectable to the crimp head  20 . The apparatus also preferably includes an attachable loader  22  for aligning and loading the elements of the crimp head  20  onto actuation mechanism  21 .  
         [0048]     Referring also to  FIGS. 7 and 8 , the frame  19  comprises a base member  25 , a front plate  26 , a rear plate  27 , and side members  28  a and b. The base member  25  provides bottom support for the remaining elements of the frame  19 . The front and rear plates  26  and  27  extend upwardly from the base member  25  and are separated a predetermined distance. Front plate  26  has a removable face plate  29 . Face plate  29  and rear plate  26  each have a predetermined arrangement of linear, angled slide grooves or slots  30  disposed on their inwardly facing surfaces, surrounding coaxial central apertures  35   a  and  b.  Each groove configuration  30  preferably have a pair of concentric members which cooperate with slide members on the head  20  elements to provide linear, radial movement to compress the stent/prosthesis, as described later.  
         [0049]     Referring also to  FIG. 26  the crimp head  20  comprises a plurality, for example eight (8) crimp segments or elements  34   a - h  which are arranged about and define a central aperture  35 . Each segment  34  has a predetermined configuration with an inwardly oriented tapered distal end  36  which is disposed toward the aperture  35  and an outwardly oriented proximal end  37 . A pair of distal rectilinear slide blocks or shoulders  38   a  and  b  are disposed on the longitudinally oriented (with respect to the working or input/output axis of the apparatus  10  in general) ends of the segment  34 . A pair of proximal slide blocks  39   a  and  b  are disposed proximally. The slide blocks  38  and  39  mate with slide grooves  30  of the plates  26  and  27 . Preferably, at least one loader mating aperture is disposed at each longitudinal end for connection to a loader (not shown). The elements  34  have predetermined substantially flat lateral faces  41  a and b which cooperate with the actuator  21 , the slide blocks  39  and the slide grooves  30  to move the elements  34 . The distal ends are preferably about 50 mm in length.  
         [0050]     As is best shown in  FIG. 6 , the actuator  21  comprises activation ring  43 , rollers  47 , arms  49 , beam  50  and screw  51 . A handle  52  is connected to the screw  51  for hand turning by the operator. The screw  51  threadedly connected to an end of the beam  50 , which is pivotally connected at pin/aperture  53  to the plates  26  and  27 . Arms  49   a  and  b  are pivotally connected to the beam  50  at one end and to the ring  43  at the other end, via brackets  48   a  and  b.  Ring  43  is preferably bifurcated, but may have a unitary structure. Ring  43  has a circumferential ring portion  45  and a plurality radial spokes  46   a - g  aligned between the crimp elements  34 . Rollers  47   a - h  are connected to spokes  46 . Rotation of the screw  51  moves the beam  50 , which moves the arms  49  and causes them to rotate the activation ring  43 . This causes rollers  47  to contact and move along the lateral faces  41  of the segments  34 . The rotary force of the rollers  47  causes the segments  34  to linearly slide along a predetermined path determined by grooves  30  as a result of slide blocks  39 . The distal ends  36  of the segments move toward one another whereby the aperture  35  becomes smaller and closes. The ends  36  engage and radially compress the prosthetic device disposed in the aperture  35 .  
         [0051]     The preferred maximum opening diameter of the crimp head  20  aperture  35  is about 35 mm and it can close to substantially zero mm. Utilizing the teachings of this invention, the maximum crimping force of the apparatus  10  is about 100 lbs. between two opposing elements  34 . Maximum crimping cycles is about 10 per head  20 .  
         [0052]     Referring to  FIGS. 9-15 , the catheter clamp  15  comprises a front plate  68  connected to a bottom block  69 , a top block  70  and a spring clamp  71 . A catheter  11  is placed in a central groove or channel of the bottom block  69  so that its open terminal or distal end abuts the front plate  68 . As is known in the art, the catheter  11  has a hollow lumen. Top block  70  is placed over the bottom block so that its groove is aligned with the catheter  11 . Clamp  71  is placed over the mated blocks  69  and  70  to hold them in place. Front plate  68  is connectable to the crimping assembly  12  so that the radially compressed, reduced diameter prosthesis can be pushed or pulled into the catheter  11  lumen via its open end. The clamp  15  will accommodate sheaths  11  up to about 8 mm in diameter and about 65 mm in length. Stent diameter reductions of at least 6 mm are obtained.  
         [0053]     Operation of the apparatus  10  is relatively simple, which minimizes the need for special operator training.. Final close diameter is dependent on the  5  specific crimping elements  34  chosen for a procedure, which substantially minimizes the possibility of operator calibration error. The crank handle  52  requires minimal physical effort to provide adequate crimping force. Introduction of the crimped stent can be accomplished by two means. A hand held quill can be used to manually push the crimped stent out of the base and into the catheter, or the stent may be pulled out of the base and into the catheter by means of an internal catheter device. The catheter clamp set  15  accommodates a wide range of french catheter sizes. The clamps  15  are quickly and easily detached and attached to the apparatus base, which reduces operation cycle time and allows for simple catheter placement. The design of the clamps  15  also provides superior alignment of the stent for insertion into the catheter when compared to other stent introduction means. The insertion aperture of the apparatus  10  minimizes gapping between crimping elements throughout its entire diameter range, which avoids damage to stents during compression. The small size and weight of the apparatus  10  allows for easy storage and transportation.  
         [0054]     The modular design of the system  10  also provides several advantages, including disposable element capability, reduced procedure cycle time, reduced storage space requirement, and reduced space requirement for sterilizing procedures. The disposable crimp elements  20  eliminate surface cross-contamination between procedures and allow preset close diameter settings on future machines. The quick-connect catheter clamp  15  allows fast and accurate location of sheath  11  within the clamp  15  and quick attachment/detachment of clamp  15  to the base  12 . They also prevent the base  12  from interfering with sheath loading by allowing operators to load the sheath  11  while the clamp  15  is not attached to the base. The C-clamp spring  71  allows quick release and removal of top clamp plate  70  and catheter  11 , while doubling as a holding grip. In one embodiment, turn crank  52  and power screw activation provides adequate holding ability at closed position under crimping loads while requiring little effort from the operator. Linearly moving crimping elements  34  reduces gapping between crimping elements  34  during aperture reduction. This also allows for development of zero gapping throughout the entire travel using injection-molded elements  34 . Additionally, it permits reduction of the overall size of the machine  10 , as well as the disposable elements  34 . Quick-change elements  34  or elements set  20  permits easy transportation, sterilization, and loading of the disposable element set  20 . It also avoids damage of the crimping elements  24  during shipping and assures correct placement within the machine base  12 . The separate submersion tank  13  reduces space required for machine storage, allows the machine to be moved in pieces, and simplifies watertight sealing. An adjustable hard stop embodiment allows fast close diameter adjustment for testing purposes. Polymer plain bearings allow for steam and EtO sterilization while reducing pivot point friction and eliminating corrosion. Lower adjustable bearing axles permit preloading of polymer roller bearings against activation rings.  
         [0055]     Referring to  FIGS. 16-19 , an alternative embodiment of the crimping assembly  112  comprises the base or frame  119 , the crimp head  120 , and an actuation mechanism  121  connected to the frame  119  and connectable to the crimp head  120 . The apparatus also preferably includes an attachable loader  122  for aligning and loading the elements of the crimp head  120  onto actuation mechanism  121 .  
         [0056]     Referring also to  FIGS. 20 and 24 , the frame  119  comprises a base member  125 , a front frame  126  and a rear frame  127 . The base member  125  provides bottom support for the remaining elements of the frame  119 . The front and rear plates  126  and  126  extend upwardly from the base member  125  and are separated a predetermined distance. Front plate  126  has a removable face plate  129 . Face plate  129  and rear plate  126  each have a predetermined arrangement of linear, angled slide grooves or slots  130  disposed on their inwardly facing surfaces, surrounding coaxial central apertures  135   a  and  b.  The groove configuration  130  preferably includes a pair of concentric members which cooperate with slide members on the head  120  elements to provide linear, radial movement to compress the stent/prosthesis.  
         [0057]     Referring also to  FIGS. 22, 23 , and  25  the crimp head  120  comprises a plurality, for example eight (8) crimp segments or elements  134   a - h  which are arranged about and define a central aperture  135 . As is best shown in  FIGS. 27-31 , each segment  134  has a predetermined configuration with an inwardly oriented tapered distal end  136  which is disposed toward the aperture  135  and an outwardly oriented proximal end  137 . A pair of distal rectilinear slide blocks or locating shoulders  138 a and b are disposed on the longitudinally oriented (with respect to the working or input/output axis of the apparatus  10  in general) ends of the segment  134 . A pair of proximal slide blocks  139   a  and  b  are disposed proximally. The slide blocks  138  and  139  mate with slide grooves  130  of the plates  126  and  127 . Preferably, at least one loader mating aperture  171  is disposed at each longitudinal end for connection to a loader  122   a  and  b.  The elements  134  have predetermined substantially flat lateral faces  141   a  and  b  of a predetermined inset configuration on one side, which cooperate with the actuator  121 , the slide blocks  139  and the slide grooves  130  to move the elements  134 . The distal ends are preferably about 50 mm in length.  
         [0058]     Returning to  FIGS. 20, 21  and  24  the actuator  121 comprises activation ring  143  with an external gear tooth profile  144  and a plurality of activation pin structures  147  disposed on its interior. The activation ring  143  is held in rotatable place between plates  126  and  127  by a capture plate lock ring  145 . A handle  152  is connected to the front plate  126  via a pin  148  at point  149 . Handle end has a drive gear  150  which mates with gear tooth profile  144  of activation ring  143 . Rotation of the arm  152  moves the gear  150 , which moves the activation ring  143 . This causes pins  147  to contact and move along the lateral faces  141  of the segments  134 . The rotary force of the pins  147  causes the segments  134  to linearly slide along a predetermined path determined by grooves  130  as a result of slide blocks  139 . The distal ends  136  of the segments move toward one another whereby the aperture  135  becomes smaller and closes. The ends  136  engage and radially compress the prosthetic device disposed in the aperture  135 .  
         [0059]     Base  119  further preferably also has segment load position indicating graphics  155 , an activation ring locating slot  156 , and a handle load position indicator  157  for ease of head  120  replacement.  
         [0060]     The descriptions above and the accompanying drawings should be interpreted in the illustrative and not the limited sense. While the invention has been disclosed in connection with an embodiment or embodiments thereof, it should be understood by those skilled in the art that there may be other embodiments which fall within the scope of the invention as defined by the claims. Where a claim, if any, is expressed as a means or step for performing a specified function it is intended that such claim be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof, including both structural equivalents and equivalent structures, material-based equivalents and equivalent materials, and act-based equivalents and equivalent acts.