Abstract:
For connecting the end of a supplemental vessel to the side of a body vessel, which has a greater diameter than the supplemental vessel, use is made of a sleeve whose one end portion is expandable for the forming of an annular end flange. As a result, the supplemental vessel, after being passed through the sleeve in the direction of the expandable end portion and folding back at least over the expandable end portion, is formable into a collar, both sides of which enclose the annular end flange inside the supplemental vessel and internally surround an opening formed therein. The distal portion of the sleeve to be inserted into the body vessel may comprise a memory material enabling the end flange to be formed without using the balloon.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]    This application is a continuation-in-part of U.S. patent application Ser. No. 09/228,749 that was filed on Jul. 23, 1997. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Technical Field of the Invention  
           [0003]    The present invention relates to the field of vascular surgery and, more specifically, to a connecting method and a connecting apparatus for vessels, especially the aorta in bypass operations on the coronary vessels. The apparatus may be used for connecting any smaller vessel like a vein, an artery or a graft of artifical material end to side of a bigger vessel like the aorta. The artificial material could be PTFE, polyurethane and Dacron. The invention might also be used for an end to side connection to other tubular organs of the human body such as big veins, biliary tracts and urogenital tracts.  
           [0004]    2. Description of the Prior Art  
           [0005]    An increased flow resistance in the various coronary vessels can jeopardise the oxygen supply to the cardiac muscle. In some cases an expansion of the vascular lumen is possible. If the flow of blood in a vessel is completely or practically completely blocked, the only thing to be done is to bypass the blocked portion to prevent an irreparable injury from arising. Such a bypass operation is usually effected by connecting a new vessel after the blocked point and connecting it to another blood vessel, for instance the aorta, which may give a sufficient flow of blood to the blood vessel after the blocked point.  
           [0006]    Such a bypass operation normally requires the use of a heart-lung machine, i.e. that the heart be temporarily stopped, since the bypass operation when connecting, for instance, the two vessels involved requires the heart to be immovable. In consequence of the connecting technique employed and the use of the heart-lung machine, the operation will be relatively time-consuming and not without risk.  
           [0007]    International Patent Application No. PCT/SE97/00804 (equivalent to U.S. patent application Ser. No. 09/192,895, filed by the present applicant) discloses a branching device, which to a considerable extent facilitates the connection of the new vessel to the coronary vessel suffering from stenosis, but this branching device is not suited for connection of the new vessel to e.g. the aorta mainly owing to the difference in size.  
         SUMMARY OF THE INVENTION  
         [0008]    The object of the present invention therefore is to provide a simple and reliable end to side connection of a smaller supplemental vessel to a bigger body vessel, for instance the aorta, which can give a sufficient flow of blood to a constricted blood vessel via a branch after the constriction. Preferably it should also be possible in this case to design the connection in a manner which makes it possible that the heart-lung machine need not be used. Most preferably it should be possible to carry out the operation by applying endoscopy.  
           [0009]    The inventive sleeve makes it possible to create a flange at the end of a first smaller supplemental vessel. The flange can be made to extend around the inside of an opening formed in the second bigger body vessel. As a result, a relatively large overlapping can be achieved in the connecting area between the first and the second vessel, which in turn permits a highly reliable connection of the two vessels.  
           [0010]    In a first embodiment, use is made of a balloon for expanding the end portion of the sleeve and, thus, for forming the flange. More precisely, the balloon is equipped with an inlet tube, which can be passed through the sleeve, such that the balloon itself will be positioned adjacent to the expandable end portion of the sleeve in order to accomplish, by inflation, the expansion thereof and at the same time also form the flange at and end of the first smaller vessel.  
           [0011]    For fixing the position of the balloon during inflation thereof such that the resulting pressure acts against the expandable end portion of the sleeve, the inlet tube of the balloon suitably is made of a substantially nonelastic material.  
           [0012]    In the preferred embodiment of the inventive apparatus, the balloon besides has a nonelastic portion, which abuts on the inlet tube and in extended state has a shape corresponding to the desired shape of the annular end flange. This ensures still more that the expandable end portion of the sleeve is affected in the correct manner for the shape of the annular flange to be correct.  
           [0013]    In a second embodiment, use is made of a memory material for expanding the end portion of the sleeve and, thus, for forming the end flange. More precisely, the distal end portion of the sleeve comprises a memory material that will force this end portion to assume the shape of a radial extending flange when it has been introduced into the bigger vessel. The bigger vessel could be any body vessel having a greater diameter than the smaller supplemental vessel.  
           [0014]    Generally, the inventive apparatus comprises a sleeve having proximal and distal portions, the proximal portion adapted to couple the end of the supplemental vessel to the sleeve, the distal portion expandable from a collapsed delivery configuration, adapted to pass through the opening in the wall of the body vessel, to an expanded deployed configuration, adapted to form an annual end flange within the body vessel; and a fixing element adapted to attach the annular end flange to the wall of the body vessel.  
           [0015]    By making the distal portion of the sleeve from a memory material the distal portion can be transformed, i.e. expanded, into the annular flange as a result of the memory material unfolding and resuming the shape of an annular flange.  
           [0016]    In order to retain the distal portion as an axial elongation of the proximal portion of the sleeve, a cap removably engaging the distal portion may be used. This cap allows for selective expansion of the distal portion by preventing expansion and unfolding of the distal portion of the sleeve. It may be manouevred by means of a wire fixed to the cap and a tube slidable on the wire.  
           [0017]    The proximal portion of te sleeve may comprise a stent having a film cover made of PTFE, polyurethane, Dacron or the like.  
           [0018]    According to the invention, a locking ring is advantageously used to fix the two vessels. The locking ring can coaxially receive the sleeve and be displaced along this to a position adjacent to the annular flange, overlapping portions of the second bigger vessel or mutually overlapping portions of the first smaller vessel and the second bigger vessel being positioned therebetween. With the aid of suitable fixing means, e.g. pins with barbs, which can be integrated with the locking ring and directed axially relative to the sleeve, portions of the second bigger vessel, and possibly portions of the first smaller vessel, can be fixed in a simple and reliable manner around the opening formed in the second bigger vessel.  
           [0019]    The entire sleeve but preferably only its expandable end portion can advantageously be made of a net-like flexible material, but the end portion of the sleeve can alternatively be formed by making a plurality of axial slots from one end of the sleeve.  
           [0020]    An inventive apparatus comprising the memory material and the cap may be used in a method according to the invention for fixing an end of a supplemental vessel to the side of a body vessel having a greater diameter than the supplemental vessel. This method comprises: providing apparatus comprising a sleeve having proximal and distal portions, the distal portion expandable from a collapsed delivery configuration to an expanded deployed configuration to form an annular end flange, and a fixing element adapted to attach the annular flange to the vessel wall; attaching the proximal portion of the sleeve to a distal portion of the supplemental vessel; forming an opening in the wall of the body vessel; inserting the distal portion of the sleeve into the body vessel in the collapsed delivery configuration; expanding the distal portion of the sleeve to the expanded deployed configuration, thereby forming the annular flange within the body vessel; and attaching the annular end flange to the body vessel with the fixing element. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]    [0021]FIG. 1 is a perspective view and shows a heart with two schematically indicated bypasses of coronary vessels each having a blocking,  
         [0022]    [0022]FIG. 2 is a perspective view and shows one embodiment of an apparatus according to the invention, as well as parts preferably associated therewith,  
         [0023]    [0023]FIGS. 3 and 4 are perspective views for explaining the method of mounting the embodiment of an inventive apparatus as shown in FIG. 2,  
         [0024]    [0024]FIG. 5 is a perspective view of the inventive sleeve with an end portion expanded into an annular flange,  
         [0025]    [0025]FIGS. 6 a - c  illustrate schematically the procedure when forming a flange on the inventive sleeve when this is enclosed by a vessel,  
         [0026]    [0026]FIG. 7 is a perspective view of a first alternative embodiment of the sleeve in FIGS. 2 and 5,  
         [0027]    [0027]FIG. 8 is a perspective view of a second alternative embodiment of the sleeve in FIGS. 2 and 5,  
         [0028]    [0028]FIG. 9 is a perspective view of a third alternative embodiment of the sleeve in FIGS. 2 and 5,  
         [0029]    [0029]FIG. 10 is a perspective view of a fourth alternative embodiment of the sleeve in FIGS. 2 and 5,  
         [0030]    [0030]FIG. 11 is a perspective view of a sleeve which is combination of the sleeves shown in FIGS. 9 and 10,  
         [0031]    FIGS.  12 - 15  are perspective views schematically illustrating the mounting of the sleeve shown in FIG. 8,  
         [0032]    FIGS.  16 - 18  are cross-section views along lines A-A, B-B and C-C, respectively, in FIG. 12, FIG. 19 illustrates a modification of the sleeve shown in FIG. 8, and  
         [0033]    [0033]FIGS. 20 and 21 illustrate schematically the procedure of forming a flange on the inventive sleeve when introducing this into a vessel.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0034]    The heart  1  shown in FIG. 1 has two coronary vessels  2 ,  3  each having a blocking  4 ,  5  in the form of a stenosis or an occlusion. FIG. 1 illustrates schematically how these blockings are bypassed by means of two vessels  6 ,  7  which can be taken from the patient himself. More specifically, one end of the vessel  6  is connected after the blocking  4 , seen in the normal direction of flow in the vessel  2 , and its other end is connected to the aorta  8 , such that a sufficient quantity of oxygen-rich blood will be supplied to the already blocked coronary vessel  2  after the blocking  4  therein. The same applies to the vessel  3 .  
         [0035]    For effecting the connection of the vessel  6  to the coronary vessel  2 , a branching device according to International Patent Application No. PCT/SE97/00804 (and corresponding to U.S. patent application Ser. No. 09/192,895 which was filed on May 16, 1997) can be used.  
         [0036]    The connecting apparatus according to the present invention concerns the connection of the other end  9 ,  10  of the vessel  6  or  7  to a vessel, e.g. the aorta  8 , (i.e. a supplemental vessel to a body vessel) which thus should give a sufficient flow of blood to provide the coronary vessel  2 ,  3  after the blocked point  4 ,  5  with a sufficient supply of oxygen.  
         [0037]    As shown in FIG. 2, the connecting apparatus according to the invention comprises a sleeve  11  of a metal or plastic that is not rejected by body tissue. The sleeve  11  comprises an end or distal portion  12  having a plurality of axial slots  13  and axially directed, intermediate ribs  14 . Except for the end portion  12 , the sleeve  11  is relatively rigid. The ribs  14  of the end portion  12  are also relatively rigid, but flexible outwards from their axial direction in FIG. 2 to a radial direction, as is best seen in FIG. 5. In the outwardly-flexed state, the ribs  14  form an annular radial end flange  15 , as is also best seen in FIG. 5.  
         [0038]    An alternative to the sleeve  11  in FIG. 5 is shown in FIG. 7. Instead of having the slots  13  and the ribs  14 , the sleeve  111  in FIG. 7 is, at least at its end  112 , made of a net-like flexible material, e.g. of stent type, so as to give the flange  115  of the sleeve  111  the appearance which is schematically shown in FIG. 7.  
         [0039]    The connecting apparatus further utilises a balloon  16 , a locking ring  17  and a locking sleeve  18 . FIG. 2 also shows part of the first blood vessel  6  adjacent to the end  9  thereof. More precisely, the blood vessel  6  is shown in the form it gets after being passed, end  9  first, through the sleeve  11  in the direction of the end portion  12  of the sleeve and subsequently has been folded back with its outer part at least over the end portion  12  of the sleeve  11 , preferably past the end portion  12 .  
         [0040]    The balloon  16  is made of an elastic material, but has an inlet tube  19  which is essentially nonelastic. The inlet tube  19  is adapted to be passed through the vessel  6 , for instance after the vessel  6  has been arranged on the sleeve  11  in the manner described above. The balloon  16  may also comprise an essentially nonelastic portion  20  adjacent to the inlet tube  19  for a purpose that will be described below.  
         [0041]    The locking ring  17  is an essentially planar ring having a plurality of axially directed pins  21 , which project in the same direction from one flat side of the ring. Each pin  21  has one or more barbs  22 , which ensure that the pin  21  remains once it has been passed through a material, in this case the vessel  6  and the end flange  15 , as will be described in more detail below.  
         [0042]    The locking sleeve  18  serves to safely retain on the sleeve  11  that part of the vessel  6  which has been folded back over the sleeve  11  and past the end portion  12 . More specifically, the locking sleeve  18  is of such a design that it can be opened and be moved inwards laterally over that part of the vessel  6  which has been folded back over the sleeve  11 , and then be clamped, such that the interiorly of the locking part positioned part of the vessel  6  is locked against the sleeve  11 . Alternatively, the locking sleeve  18  can be integrally formed with the locking ring  17 .  
         [0043]    A method for connecting the vessel  6  to the vessel  8  by means of an inventive apparatus will be described below with reference to FIGS. 3 and 4.  
         [0044]    The end  9  of the vessel  6  is first passed through the sleeve  11  and folded back over the end portion  12  and somewhat past this. The folded-back part of the vessel  6  is fixed on the sleeve  11  by means of the locking sleeve  18 . The inlet tube  19  of the balloon  16  is moved through the vessel  6 , and the locking ring  17  is moved inwards over the vessel  6  from the end thereof which is opposite to the balloon  16 .  
         [0045]    After an opening has been made in the wall of the vessel  8 , the sleeve  11  with the vessel  6  pulled over and locked by means of the locking ring  18  and with the balloon  16  positioned within the sleeve  11  is moved so far into the vessel  8  that the end portion  12  is positioned completely inside the vessel  8 . The balloon  16  is then inflated via its inlet tube  19 , the balloon  16  being in such a position that the ribs  14  are bent outwards from their axial direction to a more or less radial direction. This deformation of the end portion  12  is permanent, and thus the end flange  15  is formed. The fact that the inlet tube  19  is not elastic makes it easy for the balloon  16  to affect the ribs  14  in the correct manner for the desired outwards bending thereof. The desired shape of a collar  23  formed from the vessel  6  around the end flange  15 , i.e. the shape of the end flange  15 , can be additionally guaranteed by the balloon portion  20  adjacent to the inlet pipe  19  also being formed essentially nonelastic.  
         [0046]    When inflating the balloon  16 , the shape of the sleeve  11  changes from the shape shown in FIG. 3 to the one in FIG. 4 (and also FIG. 5).  
         [0047]    The change of the shape is shown in more detail in FIGS. 6 a - c , where the sleeve  11  and the first vessel  6  are shown in a longitudinal cross-section, but where the balloon  16  is not included for the sake of clarity.  
         [0048]    [0048]FIG. 6 a  shows the starting position, where the first vessel  6  is passed through the sleeve  11  and is folded back practically to the end of the sleeve  11  opposite the end  12 , and where the locking ring  18  fixes the folded-back part of the first vessel  6  adjacent to the former end.  
         [0049]    [0049]FIG. 6 b  shows the position after the expansion of the end portion  12  of the sleeve  11  has begun. The first vessel  6  will, on the inside of the sleeve  11 , essentially abut on the inside of the end portion  12 , while on the outside of the sleeve  11  it will extend essentially straight between the locking ring  18  and the free end of the end portion  12 . Since this free end is not fixed relative to the first vessel  6 , a relative movement will be possible, which is a requirement to enable expansion of the first vessel  6  without being damaged to a considerable extent.  
         [0050]    [0050]FIG. 6 c  shows the final position of the expansion of the end portion  12  of the sleeve  11 . Also in this case, the first vessel  6  follows the inside of the end portion  12  but does not enter the angle between the sleeve  11  and the expanded end portion  12  on the outside of the sleeve  11 . This clearance between the vessel  6  and the outside of the sleeve  11  adjacent to the expanded end portion is advantageous for the necessary seal against the second vessel  8  since a pressure will thus be exerted on the inside of the edge of the opening formed in the vessel  8 .  
         [0051]    For the final fixing of the vessel  6  to the vessel  8 , the locking ring  17  is moved down coaxially on the outside of the sleeve  11  towards the end flange  15 , while the pins  21  penetrate at least the wall of the vessel  8  and the wall of that part of the vessel  6  which is folded back over the end portion  12  and forms one layer of the collar  23 . Because of the barbs  22 , the desired locking is achieved. The pins  21  can advantageously also be made to penetrate the end flange  15  and the other layer of the collar  23  and outwards into contact with the balloon  16 , which, however, is so yieldable as not to be punctured by the pins  21 .  
         [0052]    Once the vessel  6  is safely connected to the vessel  8 , the pressure in the balloon  16  can finally be relieved, thereby making it possible to pull out the balloon through the vessel  6  by means of the inlet tube  19 .  
         [0053]    An alternative embodiment of the sleeve  211  is illustrated in FIG. 8 and comprises a stent  224  extending along a proximal portion  225  of the sleeve  211 . An end or distal portion  226  of the sleeve  211  has the same configuration as the sleeve  11  of FIG. 2, i.e. a plurality of axially extending slots  213  alternating with a corresponding plurality of ribs  214 . The sleeve  211  has a continuous cover  227  made of a film of such material as PTFE, polyurethane and Dacron, at least extending over the proximal portion  225  of the sleeve  211 . The continuous cover  227  may also be extended at least over a part of the end or distal portion  226  of the sleeve  211 . Alternatively, the end or distal portion  226  of the sleeve  211  may be covered by flocks of PTFE or the like.  
         [0054]    The ribs  214  consist of a memory material, e.g. a memory metal such as Nitinol, and are shown in a folded, axially extended state in FIG. 8, in which state the ribs  214  must be retained by a positive bias, as described below. When released the ribs  214  will unfold to a radially extending state and form an annular end flange, as illustrated in FIG. 5, without the need for any external force, such as that exerted by the inflating of a balloon.  
         [0055]    A further sleeve  311  is shown in FIG. 9 in its unfolded state having an annular end flange  315 . This sleeve  311  is a combination of a proximal portion  325  corresponding to the proximal portion  225  of the sleeve  211  shown in FIG. 8 and an end portion  326  corresponding to the end portion  112  of the sleeve  111  shown in FIG. 7. Thus, this end portion  326  consists of a net-like flexible material, e.g. of stent type, which however also is a memory material such that the end portion  326  automatically will assume the shape of an annular end flange  315  when released, as shown in FIG. 9. Further, the sleeve  311  has a stent  324  and also a cover  327 , which extends over the proximal portion  325  and the distal end portion  326 .  
         [0056]    The proximal ends of the slots  13 ,  213  of each of the sleeves in FIGS. 2 and 8 lie in a common plane, which is perpendicular to the longitudinal axis of the sleeve  11 ,  211 . The end flange formed by the unfolded ribs  14 ,  213  will also lie in the same plane. Thus, an end flange, which lies in a plane that is inclined towards the longitudinal axis of the sleeve, may be obtained by placing the proximal ends of the slots in that inclined plane, as illustrated by a sleeve  411  in FIG. 10. Of course, it is possible to otain the same result with an end or distal portion having the configuration illustrated in FIGS. 7 and 9, as also shown by a sleeve  511  in FIG. 11.  
         [0057]    Referring to FIGS.  12 - 15 , a preferred method of releasing the ribs  214  will be described. As shown in FIG. 12, a frusto-conical cap  228  is pushed over the free ends of the ribs  214  to keep them in their folded position. More precisely the distal ends of the ribs are narrowed to each other so as also to give the end or distal portion  226  of the sleeve  211  a substantially conical shape. The cap  228  is kept over-the ends of the ribs  214  by a wire  229 , which is fixed to the cap  228  preferably at central point therein. The wire  229  extends through the sleeve  211  such that a positive tension applied to the wire  229  will keep the cap  228  fixed over the free distal ends of the ribs  214 .  
         [0058]    The cap  228  may have a central hole enabling the sleeve  211  to be pushed along a guide wire extending through that central hole.  
         [0059]    In order to release the memory material of the end or distal portion  226  of the sleeve  211 , a tube  230  may be pushed along the wire  229 , as shown in FIG. 13, and ultimately lift the cap  228  from the distal end of the end portion  226  of the sleeve  211 , as shown in FIG. 14. The memory material of the end portion  226  will consequently unfold and resume its unbiased state, as illustrated in FIG. 15 for the type of sleeve illustrated in FIG. 9. Eventually, the cap  228  and the tube  230  may. be withdrawn from the sleeve  211  together with the wire  229 .  
         [0060]    FIGS.  16 - 18  illustrate cross-sections of the sleeve  211  in FIGS. 8 and 12. FIG. 16 represent the cross-section view along lines A-A in FIG. 12, showing the cover  227  encircling elements of the stent  224 . FIG. 17 represent the cross-section view along lines B-B in FIG. 12, showing the cover  227  encircling the ribs  214 . FIG. 18 represent the cross-section view along lines C-C in FIG. 12, showing the uncovered distal tips of the ribs  214  encircled by the cap  228 .  
         [0061]    It should be noted that the cover  227  encircling the ribs  214  must be extremely flexible so as not to prevent the ribs  14  from unfolding when released from the cap  228 .  
         [0062]    Referring to FIG. 19, the stent  224  of the proximal portion  225  of the sleeve  211  may have spikes  231  extending radially outwards from the peripheral surface of the sleeve  211  and through the cover  227  in order to fix the cover  227  relative to the stent  224  and also to fix an end portion of the vessel  6  relative to the stent  224  when pushed over the proximal portion  225  of the sleeve  211 .  
         [0063]    A method of using the apparatus illustrated in FIGS.  12 - 15  for connecting the vessel  6  to the vessel  8  will be described below with reference to FIGS. 20 and 21.  
         [0064]    The proximal portion  225  of the sleeve  211  is inserted and fixed in the distal end of the vessel  6 , e.g. by dilating the stent  224  by means of a balloon or by allowing a self-expanding stent  224  to expand. The cap  228  is positioned over the distal tips of the ribs  214  of the distal portion  226  of the sleeve  211  and the wire  229  extends proximally from the cap  228  and through the vessel  6 .  
         [0065]    After an opening has been made in the wall of the vessel  8 , a sheath (not shown) may be used for introducing the sleeve  211  so far into the vessel  8  that the distal portion  226  is positioned completely inside the vessel  8 . The cap  228  is then pushed off the distal portion  226  by means of the tube  230  (not shown) whereby the ribs  214  are unfolded and form an end flange  215  approaching the inner surface of the wall of the vessel  8  around the opening therein. The cap  228  may then be withdrawn from the sleeve  211  and the vessel  6  by pulling the wire  229  proximally. Finally, the vessel  6  is fixed to the vessel  8  by means of the locking ring  17  which is moved towards the end flange  215  while the pins  21  penetrate at least the wall of the vessel  8  and the covering film  227  of the end flange  215 . Because of the barbs  22 , the desired locking is achieved. The pins  21  can advantageously also be made to penetrate the end flange  215 .  
         [0066]    The expert realises that several modifications of the above-described embodiments of a connecting apparatus are conceivable within the scope of the invention as defined in the appended claims. For example, the fan shape which the ribs  14  of the end flange  15  have according to FIG. 5 can also be achieved without the slots  13  by folding the material of the end portion  12  like a fan. Also, a sleeve of the type shown e.g. in FIG. 8 but comprising ribs of a non-memory material could be used in combination with a balloon. However, it is also possible to combine a balloon with a sleeve having a distal portion, which comprises a memory material.