Abstract:
A hemostasis seal configured for use in a splittable hemostasis valve, hub, or introducer sheath to permit passage of a medical device therethrough. The seal provides a substantially fluid-tight seal around the medical device without causing excessive frictional resistance that would otherwise unduly restrict movement of the medical device through the seal. In one embodiment, the seal includes first and second resilient seal portions each having a contoured mating surface to provide a first fluid seal with respect to the medical device. The seal also may include one or more projecting portions and one or more mating receiving portions which interact to provide a second fluid seal with respect to the medical device.

Description:
TECHNICAL FIELD 
   The present invention relates generally to the field of medical instruments, and more particularly to hemostasis seals for use during medical procedures. 
   BACKGROUND 
   Various medical procedures require the introduction of one or more medical instruments into arteries or veins so that the medical instruments may be advanced to a body location requiring diagnosis or treatment. For example, a guide catheter may be advanced through the patient&#39;s vasculature to a desired treatment location, such as the right atrium of the patient&#39;s heart, for delivery of a cardiac lead. A mechanism (e.g., a hemostasis valve) including a hemostasis seal may be located at the proximal end of the guide catheter to control or inhibit the flow of blood out of the guide catheter lumen. A cardiac lead or other device (e.g., a guide wire) may be inserted through the seal and the guide catheter lumen and into the patient&#39;s vasculature, and the seal inhibits blood flow around the lead. 
   The seal should accommodate medical devices (e.g., leads, catheters and guide wires) of varying diameters without unduly restricting the movement of the device, yet still effectively seal against the flow of bodily fluids. In addition, the seal may advantageously be designed to be splittable to facilitate removal of the guide catheter while leaving the inner medical device (e.g., guide wire or lead) in place in the patient&#39;s body. 
   Accordingly, there is a need for a splittable or cuttable hemostasis seal which effectively seals against leakage of bodily fluids without unduly resisting the insertion and retraction of elongated cylindrical medical devices of varying diameters. 
   SUMMARY 
   The present invention, according to one embodiment, is a hemostasis seal configured to permit passage of a medical device. The seal includes a first resilient seal portion having a first proximal seal member with a first mating surface, a first projecting portion, and a first receiving portion. The seal also includes a second resilient seal portion having a second proximal seal portion with a second mating surface, a second projecting portion, and a second receiving portion. The first mating surface is configured to mate with the second mating surface to form a first fluid seal with respect to the medical device. In addition, the first and second projecting portions are adapted to mate with and sealingly engage the second and first receiving portions, respectively, to form a second fluid seal with respect to the medical device. 
   In another embodiment, the present invention is a hemostasis seal configured to permit passage of a medical device, and includes a first resilient seal portion with a first mating surface that includes a projecting portion; and a second resilient seal portion with a second mating surface configured to mate with the first mating surface. The second mating surface includes a receiving portion adapted to mate with the projecting portion. The seal is configured such that the first and second seal portions seal around substantially the entire circumferential surface of the medical device when it is passed between the first and second seal portions. 
   The present invention, in yet another embodiment, is a hemostasis seal configured to permit passage of a medical device. The seal includes a pair of mating seal portions each having a proximal sealing member, a distal projecting member, and a distal receiving portion. The distal receiving portion of each seal portion is sized and shaped to sealingly receive the projecting member of the mating seal portion, and the proximal sealing members and the distal projecting members are configured to sealingly and slidably engage the medical device about substantially an entire circumferential surface thereof when the medical device is passed through the seal. 
   While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic cutaway view of a hub assembly for use in a medical procedure, such as a catheterization procedure, according to one embodiment of the present invention. 
       FIGS. 2A and 2B  show proximal and distal perspective views of an assembled seal according to one embodiment of the present invention. 
       FIG. 3  shows perspective views of the mating first and second portions of the seal according to one embodiment of the present invention. 
       FIG. 4  shows the first and second seal portions from a proximal plan view, according to one embodiment of the present invention. 
       FIG. 5  shows the first and second seal portions from a distal plan view, according to one embodiment of the present invention. 
       FIG. 6  is a partial cross-sectional view of the first seal portion according to one embodiment of the present invention. 
       FIG. 7  is a perspective view of the seal according to one embodiment of the present invention, showing the seal portions partially separated. 
       FIG. 8  is a partial perspective view of the seal according to one embodiment of the present invention with a medical device passing therethrough. 
       FIG. 9  is a partial proximal plan view of the seal, according to one embodiment of the present invention, with a medical device, such as a therapy lead, passing therethrough. 
   

   While the invention is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims. 
   DETAILED DESCRIPTION 
     FIG. 1  depicts, schematically, a hub assembly  10  for use in a medical procedure, such as a catheterization procedure, according to one embodiment of the present invention. As can be seen in  FIG. 1 , the hub assembly  10  includes a body  12  having a lumen  16  therethrough, and a seal  50  according to one embodiment of the present invention. The lumen  16  is sized to permit passage of a medical device  18  such as, for example, a therapy lead, guiding catheter, or a guide wire. The seal  50  is retained within the hub body  12 , and is adapted to maintain a substantially positive fluid seal around the medical device  18  that is passed through the lumen  16 . The hub  10  may be coupled to another medical device  51  such as a catheter or introducer sheath. 
     FIGS. 2A and 2B  show proximal and distal perspective views of an assembled seal  50  according to one embodiment of the present invention. As shown in  FIGS. 2A and 2B , the seal  50  is, in one embodiment, generally cylindrical with a longitudinal axis  52  and a perimeter  53 , and is composed of a first seal portion  56  and a mating second seal portion  58 . The seal portions  56  and  58  are substantially equivalent in overall size and join at a proximal joint  64  and a distal joint  66  to form a proximal entrance area  70  and a distal exit area  76 . Because the seal  50 , in one embodiment, is composed of two, separate seal elements, it is particularly adaptable for use in splittable or cuttable medical devices such as splittable hemostasis or bleedback control valves or splittable introducer sheaths. In one embodiment, the seal portions  56  and  58  may be attached at or near the seal perimeter using an attachment method that permits the seal  50  to be readily split or cut. 
   In general, the shape of the seal  50  will be dictated by the configuration and requirements of the hemostasis valve, hub, or introducer sheath into which the seal  50  is inserted. In one embodiment, the seal  50  is generally cylindrical with an outer diameter D of from about 0.250 inches to about 0.750 inches. In one embodiment, the diameter D is about 0.600 inches. In another embodiment, the diameter D is about 0.450 inches. Although  FIGS. 2A and 2B  depict a cylindrical seal  50 , this is not a requirement. To the contrary, other shapes (e.g., rectangular, elliptical) are within the scope of the present invention. 
   In one embodiment, the seal  50  may be made of polyisoprene. In other embodiments, other resilient materials may be used to form the seal  50 , including, without limitation, silicone, latex, neoprene, and other rubber-based compounds as will be understood by those of ordinary skill in the art. 
   In one embodiment, shown in  FIGS. 2A and 2B , the proximal entrance area  70  is generally conical and has an apex  78  near the longitudinal axis  52 , and the distal exit area  76  is concave and may include a generally circular planar portion  82  disposed about and generally perpendicular to the longitudinal axis  52 . In one embodiment, the planar portion  82  has a diameter d of from about 0.030 inches to about 0.100 inches. In one embodiment, the planar portion  82  has a diameter d of about 0.070 inches. In another embodiment, the planar portion  82  has a diameter d of about 0.050 inches. In other embodiments, the planar portion  82  may have a non-circular shape (e.g., rectangular, elliptical) 
   In one embodiment, the planar portion  82  may be centered about the longitudinal axis  52  and, in turn, the apex  78  of the proximal entrance area  70 . In another embodiment, either or both of the planar portion  82  and the apex  78  of the proximal entrance area  70  may be offset from the longitudinal axis  52 . 
   The seal  50  may optionally include means for facilitating retention of the seal  50  within another medical device such as, for example, a hemostasis valve or an introducer sheath. Such means may include a proximal retaining ring  90  and/or a distal retaining ring  92 . 
     FIG. 3  shows perspective views of the first and second seal portions  56  and  58 , respectively. Additionally,  FIGS. 4 and 5  are proximal ( FIG. 4 ) and distal ( FIG. 5 ) plan views of the seal portions  56  and  58 . As shown in  FIGS. 3 ,  4  and  5 , the first seal portion  56  includes a first proximal sealing member  114  having a first mating surface  118 , a first projection  132 , a first distal wall  134  defining a first recess  136 , and a first planar subportion  140 . The second seal portion  58  includes a second proximal sealing member  146  having a second mating surface  150 , a second projection  162 , a second distal wall  164  defining a second recess  166 , and a second planar subportion  170 . 
   In one embodiment, the mating surfaces  118  and  150  are each contoured to generally form an ‘S’-shape. Accordingly, in this embodiment, the proximal joint  64  in the assembled seal  50  is also ‘S’-shaped (See  FIG. 2A ). In one embodiment, each half of the ‘S’ of the contoured mating surfaces  118  and  150  may have a radius of curvature of from about 0.125 inches to about 0.250 inches. In one embodiment, the radius of curvature is about 0.150 inches. In another embodiment, the radius of curvature is about 0.187 inches. In other embodiments, the mating surfaces  118  and  150  may be configured in other shapes. When the seal portions  56  and  58  are assembled to form the seal  50 , the proximal sealing members  114  and  146  form the proximal entrance area  70  (See  FIG. 2A ). 
   In one embodiment, the projections  132  and  162  are generally sized and shaped to be inserted into and to sealingly mate with and engage the recesses  166  and  136 , respectively, when the seal portions  56  and  58  are assembled to form the seal  50 . When so engaged, the projections  132  and  162  generally form the distal exit area  76  (See  FIG. 2B ). In the assembled seal  50 , the planar subportions  140  and  170  join to form the generally planar portion  82  (see  FIG. 2B ). 
   The recesses  136  and  166  are sized and shaped to receive the projections  132  and  162 . In one embodiment, when the seal  50  is assembled, substantially all of the adjacent surfaces of the projections  132  and  162  and the recesses  166  and  136  are in sealing contact with one another. 
   In one embodiment, as shown in  FIGS. 3 ,  4  and  5 , the projections  132  and  162  and, accordingly, the recesses  136  and  166 , are curved, although this is not a requirement of the present invention. In other embodiments, for example, the projections  132  and  162  may be substantially triangular or rectangular, and the recesses  166  and  136  are shaped to sealingly receive the projections. 
   As shown in  FIGS. 4 and 5 , in one embodiment, the first proximal sealing member  114  intersects the first projection  132 , and the second proximal sealing member  146  intersects the second projection  162 , at approximately 90 degree angles and at approximately the longitudinal axis  52 . As a result, the proximal sealing members  114  and  146  overlap the distal joint  66  (see  FIG. 2B ), and the projections  132  and  162  overlap the proximal joint  64 , at substantially all points other than the longitudinal axis  52 . As discussed below, this results in sealing around substantially the entire circumferential surface of a medical device (e.g., a cardiac lead) that is inserted through the seal. 
     FIG. 6  is a partial cross-sectional view of the first seal portion  56  taken along the line X-X in  FIG. 4 . It should be understood that, although not shown in  FIG. 6 , the features of the second seal portion  58  are generally configured to have the same size and shape as the corresponding features of the first seal portion  56 . For example, the second proximal sealing member  146 , the second projection  162 , the second recess  166 , and the second planar subportion  170  have generally the same dimensions and shape as the first proximal sealing member  114 , the first projection  132 , the first recess  136 , and the first planar subportion  140 , respectively. 
   Thus, as shown in  FIG. 6 , the proximal sealing members  114  and  146  are tapered radially inward, having a thickness t 1  near the seal perimeter  53  and a thickness t 2  near the apex  78 . In one embodiment, the thickness t 1  may range from about 0.075 inches to about 0.175 inches, and the thickness t 2  may range from about 0.005 inches to about 0.025 inches. In one embodiment, the thickness t 1  is about 0.125 inches and the thickness t 2  is about 0.0075 inches. 
   As further shown in  FIG. 6 , the projections  132  and  162  are also thicker near the seal perimeter  53  than near the longitudinal axis  52 , and transition into the planar subportions  140  and  170 . In one embodiment, the projections  132  and  136  have a thickness t 3  near the perimeter  53  that may range from about 0.075 inches to about 0.175 inches, and a thickness t 4  of the planar subportions  140  and  170  of from about 0.005 inches to about 0.025 inches. In one embodiment, the thickness t 3  is about 0.125 inches and the thickness t 4  is about 0.0075 inches. 
   In the embodiment shown in  FIG. 6 , the projections  132  and  162  each have a contoured distal face  180 , although in other embodiments, the projections  132  and  162  may have different shapes (e.g., concave) or may have a straight taper similar to the proximal sealing members  114  and  146 . 
   In one embodiment, the thickness t 2  of the proximal sealing members  114  and  146  near the apex  78  is thicker than the thickness t 4  of the planar subportions  140  and  170 . In one such exemplary embodiment, the thickness t 2  is about 0.010 inches and the thickness t 4  is about 0.005 inches. 
   Table 1 below shows the dimensions, in inches, discussed above for various exemplary embodiments of a seal  50  according to the present invention. 
   
     
       
             
             
             
             
             
             
             
           
             
             
             
             
             
             
             
           
         
             
                 
                 
             
             
                 
               D 
               d 
               t1 
               t2 
               t3 
               t4 
             
             
                 
                 
             
           
           
             
                 
             
           
        
         
             
               1 
               0.450 
               0.050 
               0.125 
               0.0075 
               0.125 
               0.0075 
             
             
               2 
               0.450 
               0.070 
               0.125 
               0.010 
               0.125 
               0.010 
             
             
               3 
               0.600 
               0.050 
               0.125 
               0.0075 
               0.125 
               0.0075 
             
             
               4 
               0.600 
               0.070 
               0.150 
               0.010 
               0.150 
               0.010 
             
             
               5 
               0.300 
               0.030 
               0.075 
               0.005 
               0.075 
               0.005 
             
             
               6 
               0.500 
               0.045 
               0.125 
               0.010 
               0.125 
               0.005 
             
             
               7 
               0.750 
               0.080 
               0.150 
               0.015 
               0.150 
               0.010 
             
             
               8 
               0.750 
               0.100 
               0.175 
               0.025 
               0.175 
               0.025 
             
             
                 
             
           
        
       
     
   
     FIG. 7  is a perspective view of the seal  50  according to one embodiment of the present invention, showing the seal portions  56  and  58  partially separated to show how the projections  132  and  162  effectively interlock. 
     FIG. 8  is a partial perspective view, and  FIG. 9  is a partial proximal plan view, of the seal  50  according to one embodiment of the present invention, with a medical device, such as a therapy lead  200 , passing therethrough. For clarity, only the second seal portion  58  is shown in  FIGS. 8 and 9 . Exemplary medical devices that may be accommodated by the seal  50  according to one embodiment of the present invention include, without limitation, guide wires, therapy leads, and guide catheters, with outer diameters ranging from about 0.010 inches to about 0.170 inches. As will be apparent to those of ordinary skill in the art, the foregoing types of medical devices and the corresponding ranges of diameters are merely exemplary, and the seal  50  of the present invention may be adapted to accommodate larger or smaller diameter medical devices as may be required for a particular procedure. 
   As shown in  FIGS. 8 and 9 , the proximal sealing members  114  and  146  and the projections  132  and  162  interact to substantially fully encapsulate the lead  200  as it is passed between the seal portions  56  and  58 . The contoured shape of the mating surfaces  118  and  150  tends to cause the proximal sealing members  114  and  146  to wrap around the lead  200 . Similarly, in one embodiment, the projections  132  and  162  tend to wrap around the lead  200  as it passes through the seal  50 . Working together, the proximal sealing members  114  and  146  and projections  132  and  162  substantially fully encapsulate a generally cylindrical medical device that is passed between the seal portions  56  and  58 . 
   Additionally, the orientation of the mating surfaces  118  and  150  to the projections  132  and  162  result in at least the proximal sealing members  114  and  146 , or the projections  132  and  162 , being in sealing contact with the medical device  200  around the entire surface of the device. With a seal lacking projections  132  and  162 , insertion of a medical device between the seal elements would result in leakage at points approximately 180 degrees apart where the two seal member join. As is apparent in  FIGS. 4-7 , however, the projections  132  and  162  overlap the proximal joint  64  at all points other than the longitudinal axis  52  and accordingly, in one embodiment, the apex  78 , which is the point of entry of the medical device through the seal  50 . Thus, the projections  132  and  162  seal around the medical device immediately distal to any areas of separation that may occur in the proximal joint  64 . Similarly, the proximal sealing members  114  and  146  overlap the distal joint  66  at all points other than the apex  78 . This has the resulting effect of sealing around the regions on the medical device proximal of the points of corner separation in the distal joint  66 . Thus, the inserted medical device, the overlapping proximal sealing members  114  and  146 , and the projections  132  and  162  interact to eliminate any pathways for leakage of bodily fluids through the seal  50 . 
   The projections  132  and  162  also operate to stabilize and hold the seal portions  56  and  58  in alignment when the lead  200  or other medical device is inserted through the seal  50 . A seal without such projections may tend to become misaligned due to, for example, relative translation of the two separate seal components along their joint line, when a device is inserted into or removed from the seal. In the present invention, however, according to one embodiment, the walls  128  and  158  in the recesses  136  and  166  restrict displacement of the projections  132  and  162 , respectively. This in turn restricts relative movement of the seal portions  56  and  58 . In addition, the interlocking design of the projections  132  and  162  and the recesses  136  and  166 , respectively, similarly restricts rotational movement of the seal elements  70  and  76  relative to each other. 
   The stabilizing effect of the projections  132  and  162  is further promoted by their profiles. Near the longitudinal axis  52 , the projections  132  and  162  are relatively thin, which promotes effective sealing while at the same time reduces resistance to movement of the lead  200  or other medical device through the seal  50 . This provides a beneficial combination of effective sealing without unduly restricting the travel of the medical device through the seal  50 . At the same time, the thicker portions of the projections  132  and  162  near the perimeter of the seal  50  beneficially stiffens the projections which further inhibits misalignment of the seal portions  56  and  58 . 
   In addition, the geometry of the seal  50  advantageously promotes centering the medical device, such as the lead  200 , as it is passed through the seal  50 . The orientation of the projections  132  and  162  at approximately 90 degrees relative to the proximal joint  64  inhibits the lead  200  from sliding along the proximal joint  64 , as would tend to occur if the projections  132  and  162  were not present. Accordingly, the projections  132  and  162  operate to maintain the lead  200  or other medical device at a position at or near the longitudinal axis  52  (see  FIG. 2A ). 
   Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, while the embodiments described above refer to particular features, the scope of this invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the claims, together with all equivalents thereof.