Abstract:
A remote endarterectomy ring stripper ( 1 ) includes an elongate shaft ( 8 ), having distal ( 36 ) and proximal ( 32 ) ends, an intima stripping ring ( 4, 34 ) mounted to the distal end of the elongate shaft and an intima cutter assembly having an intima cutting element ( 22, 42, 56, 60 ), at the stripping ring, operated by a user-operated cutting element actuator ( 10; 12, 50 ). Movement of the cutting element severs a length of intima ( 26 ), which has been separated from the wall ( 28 ) of the blood vessel ( 23 ), passing through the stripping ring.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part patent application of U.S. patent application Ser. No. 08/633,730 filed Jun. 10, 1996, now U.S. Pat. No. 5,843,102, which is the national phase application of International Application No. PCT/NL94/00254, entitled “AN INSTRUMENT FOR LOOSENING AND CUTTING THROUGH THE INTIMA OF A BLOOD VESSEL AND A METHOD THEREFOR,” international filing date Oct. 18, 1994, published May 4, 1995, which claims the benefit of NL 9301842, filed Oct. 25, 1993, the disclosures of which are incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to a device or assembly for the treating of blood vessels and more specifically to a device or assembly for performing a remote endarterectomy or dilatation and to an endarterectomy method using the device. 
     It is known that narrowing or blockages (thromboses) can occur in blood vessels, particularly in older people. This is often caused by the effects of deposits on the inside walls of the blood vessels leading to hardening or calcifying of the blood vessels. This has dangerous consequences for the health, because the quantity of blood now able to flow through the blood vessel is drastically reduced. In order for effective blood circulation to occur, and to avoid possible limb amputation for example, any blockage or obstacle in the blood vessels must be removed. 
     One conventional method for treating hardening of the blood vessels involves a complicated operation. In the case of the artery between the groin and knee, this is quite a severe operation. The patient is cut open at the groin and the knee, whereafter the artery is completely removed and replaced by an artificial artery. This can be especially hard on and dangerous for older people, particularly because of the duration of the operation. The operation is also expensive and requires a lengthy hospital recovery period for the patient. Additionally, there is a danger of rejection of the artificial blood vessel by the body, which can lead to further post operation complications. 
     Another procedure for treating totally or partially blocked blood vessels, called endarterectomy, separates the inner layer of the blood vessel, the so called tunica-intima or intimal lining or intima, from the blood vessel wall using a ring stripper. The intimal lining, which has been separated from the vessel wall over the length of the blockage, is then removed from the patient along with the blockage. A new intimal lining then grows back to replace the removed intimal lining. See, for example, U.S. Pat. Nos. 2,944,552 and 4,621,636. 
     Conventional endarterectomy procedures are typically carried out using two incisions, one on either side of the blockage. The first incision permits access to the vessel by the instrument; the second incision permits access to the distal end of the separated intima so the separated intima may be severed from the vessel wall and then removed through the first incision. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a remote endarterectomy ring stripper which requires only one incision and provides for quicker, less expensive, more patient-friendly endarterectomy procedures. 
     The remote endarterectomy ring stripper includes an elongate shaft having distal and proximal ends. An intima stripping ring, having an open interior, is mounted to the distal end of the elongate shaft. The ring stripper also includes an intima cutter assembly having a cutting element and a cutting element actuator. The cutting element is located at the stripping ring and is movable along a cutting path across at least a portion of a cutting region. The cutting region passes through the open interior of the stripping ring. 
     The cutting element actuator has a first end, at the proximal end of the shaft, and a second end, operably coupled to the cutting element. The cutting element actuator is manipulated by the user to permit the user to cause the cutting element to move along the cutting path so to sever a length of intima, which has been separated from the wall of the blood vessel and passes through the open interior of the stripping ring. 
     The cutting element can take a number of different forms. In one embodiment the stripping ring is formed by a pair of stripping ring portions positioned adjacent to one another. The two stripping ring portions are movable with adjacent surfaces sliding against one another; the sliding surfaces have appropriately positioned cutting edges which sever the intima passing through the interior of the stripping ring. In another embodiment the cutting element includes an intima-severing wire initially positioned adjacent to the stripping ring; the cutting element is actuated by pulling on the wire to cause the wire to sever the intima passing through the stripping ring. Further embodiments use pivotal, retractable, or otherwise movable blades to cut the intima passing through the stripping ring. Still other types of cutting elements can be used as well. 
     A blocked blood vessel is able to be cleaned using the present invention so that the need for a time consuming, expensive bypass operation, which is harsh on the patient, is eliminated. The requirement of using an artificial replacement blood vessel is no longer present, because the old vessel is now in a state to again effectively fulfill its function. Therefore, rejection of an artificial blood vessel by the body, and its ensuing problems, do not play a role here. The hospital recovery period is shortened due to the less exacting nature of this operation, whereby the costs decrease and more hospital beds become available. 
     The stripping ring preferably has a cross section in the form of a truncated cone, the nose of which comprises a blunt edge which projects in the direction of the incision. In this way the blunt edge separates the intima from the blood vessel wall when the instrument is pushed between the intima and the blood vessel wall. The intima is thus peeled further away from the blood vessel wall and is subjected to a sort of bottle neck effect, caused by the cone form, between the two sides of the ring. 
     The length of the shaft may depend on the length of the blood vessel to be cleaned, and/or the extent of calcification in the blood vessel. 
     The cutting element actuator, in one embodiment, comprises a part that can take the form of a filament or a wire, that extends through the shaft, which can be moved with respect to the shaft by a user-actuated manipulator. In one embodiment the manipulator comprises a lever associated with the shaft. In this way the intima can be separated from the blood vessel wall and cut through at the required distance by the instrument, which is operable from outside the body. 
     The separation of the intima from the blood vessel wall and the cutting through and severing of the intima is consequently quick and able to be carried out in an elegant and simple manner. After cutting through of the intima, the intima plus blockage are removed through the single incision. 
     Further advantages, characteristics and details of the present invention will become clear from the following description which refers to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partly broken away perspective view of a first embodiment of the invention; 
     FIG. 2 is a perspective view of the embodiment from FIG. 1, showing operation thereof; 
     FIG. 3 is the embodiment from FIG. 1 applied to an embodiment of the method according to the present invention; 
     FIG. 4 is a detail of part of the embodiment from FIG. 1 in the action of cutting through an intima; 
     FIG. 5 is an overall view of an alternative embodiment of the invention in which an intima-severing wire is initially housed within a groove formed within the stripping ring, the intima-severing wire being connected to an actuator wire which extends through the tubular shaft to a pull ring extending from the handle at the proximal end of the shaft; 
     FIG. 5A is a cross-sectional view taken along line  5 A— 5 A of FIG. 5; 
     FIG. 5B is a simplified view illustrating the guillotine movement of the intima-severing wire within the stripping ring as the user pulls on the pull ring of FIG. 5; 
     FIG. 6 illustrates a further embodiment of the invention in which an actuator wire is connected to each end of the intima-severing wire so that pulling on one or both of the actuator wires causes the intima-severing wire to move as suggested in FIG. 5B, but also allowing a sawing action to be provided in addition to the guillotine action of FIG. 5B; 
     FIG. 7 illustrates a further embodiment of the invention in which a single retractable blade has been extended from the distal end of the hollow shaft to pierce the intima passing through the stripping ring, the intima being severed by rotating the stripping ring; 
     FIG. 7A is a side view of the embodiment of FIG. 7; 
     FIG. 8 illustrates a further embodiment of the invention in which a blade, pivotally mounted to the distal end of the stripping ring, is actuated to pivot across the interior of the stripping ring, after which the user rotates the stripping ring to completely sever the intima; 
     FIG. 9 illustrates a further embodiment of the invention in which a single curved blade is pivotally mounted at either end to opposite sides of the stripping ring so that when actuated, the curved blade cuts the intima in a scooping fashion; 
     FIG. 10 is a simplified view showing an embodiment in which a series of small blades arranged in an iris pattern move inwardly from a retracted position within the ring stripper to sever the intima passing through the ring stripper; 
     FIGS. 11 and 11A are views of a final embodiment of the invention in which the ring stripper is a segmented, telescoping ring stripper, at least a portion of the inner edge of the telescoping stripping ring is sharpened so that when moved from the expanded condition of FIG. 11 to the fully retracted condition of FIG. 11A, the sharp interior cutting edge severs the intima. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A first embodiment of a remote endarterectomy ring stripper  1 , also referred to as instrument  1 , according to the invention (FIG. 1) comprises two rings  2 ,  4  supported at an angle which are insertable around the intima, the front ring  2  having a blunt edge  6 , a hollow shaft or pin  8 , an actuator wire or a filament  10 , movable in the hollow pin  8 , which is connected via a hinge  15  of the lever  12  with a projection  14  of the filament  10 , a grip part  16 , which also acts as base for the lever  12 , and a slot  18  in the grip part  16  wherein the projection  14  and the moveable part  10  extend. The hollow pin  8  is secured to the grip part  16 , whilst the filament  10  moves in the slot  18 . The slot  18  narrows to a narrower slot  19  (FIG. 2) which extends completely through the grip  16 . 
     In FIG. 2, the lever  12  is in the raised position. On raising the lever  12 , the filament  10  in the hollow pin  8  is displaced to the grip part  16 , via the projection  14 , so that a part  20  of the moveable part  10  moves through the channel  19  and projects out from the rearside of the grip part  16 . On carrying out this action the front ring  2 , which is supported by the moveable part  10 , moves downwards with respect to the second ring  4 , so that a scissor movement is obtained between the two rings  2 ,  4 . The filament  10  extends out of the under side of the hollow pin  8  through an opening  21 , whilst on the upper side the hollow pin  8  extends to the rings  2 ,  4 . 
     The blunt edge  6  of the front ring  2  extends inwardly to a sharp inner edge  22  of the front ring  6  (FIGS.  1  and  2 ). 
     An instrument  1  according to the invention is inserted into the artery  23 , see FIG. 3, via a small incision  24  of about 8-10 cm in the groin, between the groin and the knee, in such a way that the rings  2 ,  4  extend in the direction of the knee whilst the lever  12  and the grip part  16  are located outside of the body, near the incision  24  of the artery  23 . 
     The front ring  2  is moved downwards with respect to the rear ring  4 , by the scissor movement of the two rings  2 ,  4  (FIG.  4 ), causing the intima  26 , which is already separated from the blood vessel wall  28 , to be pinched between the two rings  2 ,  4 . It is clear that further downward movement of the front ring  2  will result in the cutting through and severing of the intima  26  which is held between the sharp edge  22  of the front ring  2 , supported by the hollow pin  8 , and the rear ring  4 , supported by the moveable part of filament  10 . 
     The rings  2 ,  4  are preferably sharpened for about 40%, or 144° of their contours, front ring  2  sharpened along its upper inner side and rear ring  4  sharpened along its lower inner side, in order to achieve a highly efficient shear, scissor-like cutting movement when front ring  2  is moved relative to rear ring  4 . This scissor-like cutting effect is particularly efficient in cutting through hardened, calcified material as relatively little mechanical force is needed in operation of the instrument, to effect a neat cut. 
     The rings  2 ,  4  are flattened where they meet, as shown in FIG. 2, in order to fit together as a single ring so that no obstructions project which could damage the outer layer of the blood vessel during insertion, operation and/or removal of the instrument. 
     From clinical tests it has been determined that an effective cutting through and severing is achieved when the rings are mounted at an angle of 45° relative to the filament and hollow pin. However, it will be obvious that the rings could be mounted in any direction and in any relative position in order to achieve efficient cutting. 
     At this angle of 45° it was found that the following ring diameters, with respect to the inner diameter of the blood vessel, yielded efficient separation of the intima from the blood vessel wall and cutting through the severing of the intima and any hardened, calcified material therein. 
     
       
         
               
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                 Inner diameter blood vessel 
                 diameter rings 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 4 mm 
                 6.5 mm 
               
               
                   
                 5 mm 
                 7.5 mm 
               
               
                   
                 6 mm 
                 8.5 mm 
               
               
                   
                 7 mm 
                 9.5 mm 
               
               
                   
                 8 mm 
                 10.5 mm  
               
               
                   
                 10 mm  
                 12.5 mm  
               
               
                   
                   
               
             
          
         
       
     
     On inserting the instrument into an already opened blood vessel (FIGS. 3,  4 ) the front ring  2  and the rear ring  4  encircle the intima  26 . The instrument is then pushed through the blood vessel. The blunt edge  6  of the front ring  2  separating the intima from the blood vessel wall  28 , whereby the intima  26  is forced further inward away from the blood vessel wall by a funnel effect brought about by the front ring  2 . After the two rings  2 ,  4  have been moved to a required distance in the blood vessel, for instance to a point where there is no more blockage of the blood vessel, the movement is stopped and the lever  12  is raised which brings about the earlier stated scissor movement for the cutting through and severing of the intima. 
     In order to further improve cutting and severing, at least one of the rings, preferably the front ring  2 , may be vibrated during the scissor movement. 
     The intima and the blockage therein can be removed either by removing the instrument from the blood vessel or by any other way. 
     It will be noted that the present invention is not limited to the above-described embodiment of FIGS. 1-4. For instance in a further (not shown) embodiment of-the present invention the filament and hollow pin may be reversed so that the filament extends out of an opening on the upperside of the hollow pin, the position of the filament&#39;s and hollow pin&#39;s respective rings being reverse, whereupon cutting is achieved by pushing the filament instead of pulling the filament. In yet another (not shown) embodiment of the present invention, the hollow pin may be pushed to achieve a cutting movement, instead of pulling the filament. 
     A further advantage of the present invention is that blocked blood vessels, specifically the artery between the groin and the knee, can be unblocked to allow the insertion, via this artery, of a prosthetic into the aorta to treat patients who, along with blocked blood vessels, also have aneurysms for instance. For these patients the chest now no longer has to be opened in order to treat the aneurysm, as the now, unblocked artery between the knee and the groin yields a prosthetic access to the aorta. 
     FIGS. 5-11A illustrate alternative embodiments of the invention with corresponding reference numerals referring to corresponding structure. Ring stripper  1   a , see FIGS. 5-5B, comprises a tubular shaft  8   a  having a handle  30  at the proximal end  32  of shaft  8   a  and a stripping ring  34  at the distal end  36  of shaft  8   a . Stripping ring  34  and tubular shaft  8   a  are sized and configured to operate as an intima ring stripper in a generally conventional manner. Stripping ring  34  defines an interior  38  through which the severed intima  26  passes. Stripping ring  34  has a groove  40  along its inner circumference, see FIG. 5A, within which an intima-severing wire  42  is initially housed. Wire  42  can be temporarily maintained in groove  40  in a number of different ways, including magnetic attraction of wire  42  in groove  40 , an expanding spring force biasing wire  42  into groove  40 , snap fit of wire  42  in groove  40 , releasable adhesive in groove  40 , etc. One end  44  of wire  42  is fixed to stripping ring  34  at position  46  while the other end  48  is connected to an actuator wire  10   a . Actuator wire  10   a  is connected at its proximal end to a pull ring  50 . This permits the user to sever intima  26  passing through interior  38  of stripping ring  34  by pulling on pull ring  50  causing the intima-severing wire  42  to move in direction  52  of FIG. 5B from its initial position in groove  40  to a fully retracted position. Severing wire  42  is constructed to sever intima  26  by virtue of the size, shape, and surface character of the wire. For example, wire  42  could have a sharpened edge or diamond particles coating its surface. 
     FIG. 6 illustrates the distal end of an alternative embodiment of the invention in which stripping ring  34   a  houses an intima-severing wire  42   a.  However, both ends,  44   a ,  48   a  of wire  42   a  are connected to separate actuator wires  10   b  and  10   c . Actuator wires  10   b  and  10   c  are connected to separate pull rings (not shown), and can be pulled in unison or alternatingly to create a pure guillotine action or a sawing action as indicated by arrows  52   a ,  54 . 
     FIG. 7 shows an embodiment in which a retractable blade  56 , normally housed within distal end  36   a  of the hollow shaft, can be extended out from the hollow shaft as shown in FIGS. 7 and 7A to pierce intima  26 . To sever the intima, the instrument must be moved in a rotational motion over a total arc of about 360E, such as 180E in either direction from a start position, to completely sever intima  26  as indicated by arrow  58 . 
     FIG. 8 illustrates an embodiment in which a single blade  56   c  moves from a nested position within or adjacent to stripping ring  34   c  to the cutting position of FIG. 8 to cut a portion of intima  26 . The complete cut is made by rotating stripping ring  34   c  about 90° to 180° to completely sever intima  26  as suggested by arrow  58   c.    
     FIGS. 9 and 9A illustrate a further embodiment of the invention in which a single curved blade  56   d  is pivotally mounted at either end to opposite ends of stripping ring  34   d . Blade  56   d  is pivoted about 180° from a position aligned with one side of the stripping ring  34   d  to the other side of stripping ring  34   d  to create a curved, scooping-motion cut through intima  26 . 
     Turning now to FIG. 10, stripping ring  34   e  is shown to have a number of small camera iris-type of blades  56   e . Blades  56   e  move from a retracted position, providing a substantially unobstructed interior of stripping ring  34   e,  to an extended, cutting position shown in FIG. 10, at which point blades  56   e  have severed intima  26  passing through stripping ring  34   e.    
     FIGS. 11 and 11A illustrate a telescoping stripping ring  34   f  having an inside cutting edge  60  formed on the segmented outer stripping ring portion  62 . Outer portion  62  passes over the segmented inner portion  64  of stripping ring  34   f.  If necessary, stripping ring  34   f  can be rotated when in the cutting condition of FIG. 11A to completely sever intima  26 . This can be done easily because the outside diameter of stripping ring  34   f  in the condition of FIG. 11A is smaller, thus not creating any undue stretching forces on the vessel. 
     Additional modifications and variations are conceivable within the range of the following claims.