Abstract:
The expandable sheath and system for intravascular insertion of a medical implement includes a cannula for entering a lumen of a vascular vessel of a patient, a guide wire insertable into the lumen, an introducer and dilator adapted to follow the guide wire into the lumen, an expandable sheath positioned on the introducer and dilator, with the expandable sheath being adapted to be positioned in the vessel, and an extension collar. The medical implement is received within the vessel by passing through the sheath upon separating the introducer and dilator therefrom. In one embodiment, a linear array of perforations formed through the expandable sheath allow for expansion. Alternatively, an external slit may be provided for selective expansion of the sheath.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/765,213, filed Feb. 15, 2013; U.S. Provisional Patent Application Ser. No. 61/791,748, filed Mar. 15, 2013; and U.S. Provisional Patent Application Ser. No. 61/792,352, filed Mar. 15, 2013. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to medical devices, and particularly to an expandable sheath for insertion of an arterial catheter. 
         [0004]    2. Description of the Related Art 
         [0005]    Less invasive medical procedures for various operations are, of course, highly desirable, as they result in less trauma for the patient, faster healing, less time spent in the hospital, less expense to the patient, and the ability for the patient to return to his or her work or normal lifestyle more rapidly. This is particularly true in cardiac procedures. If a surgical procedure can be accomplished without an open chest, or open-heart, surgery, such less invasive practices are much more desirable. 
         [0006]    An example of such is the opening of various coronary arteries that have become obstructed by cholesterol deposits. The correction of this condition originally required surgery to access the interiors of the arteries directly for curettage. More recently, such arterial deposits have been flattened or pressed against, or into, the walls of the arteries by the balloon angioplasty procedure, wherein an inflatable device is inserted into the artery and expanded to widen the artery for proper blood flow. Accessing the femoral artery in one of the thighs of the patient, and working a catheter through the artery until reaching the desired target area in the coronary artery conventionally accomplish this procedure. The balloon is expanded to widen the artery when the balloon reaches the target area. While this procedure is clearly less invasive than open chest surgery, the length of the catheter and sheath required, as well as the delicate manipulation of the catheter and sheath through such a relatively long pathway, make this a relatively intricate procedure. Various other procedures, such as coronary angioplasty, coronary arteriography, cardiac catheterization, etc., also typically involve the insertion of catheters, guides, and the like through an introducer sheath in the femoral artery. 
         [0007]    More recently, there has been interest in developing techniques for access of coronary arteries through the radial artery in the wrist or lower arm of the patient. This procedure has advantages, including the far shorter distance required for manipulation of the distal end of the catheter from the entry site to the coronary artery. This also generally results in fewer traumas to the patient, as the percutaneous opening need not be so large when accessing the smaller radial artery in comparison to the femoral artery. However, the radial artery is a smaller diameter vessel than the femoral artery. Generally, it is desirable to keep the puncture of the vessel as small as possible. Nevertheless, coronary procedures often require the use of larger diameter guides, catheters, etc., than desirable in the radial artery. 
         [0008]    The medical profession uses a measurement system known as the French system for the diameters of these various sheaths and catheters. In the French system, one French is equal to one third of a millimeter, i.e., 3 F=1.0 mm, with a linear correspondence between the French and metric dimensions. Typical guide and sheath diameters for use in a radial artery intervention procedure might be 2.00 mm or 6 French for the sheath, but the use of a larger 2.33 mm or 7 French guide is desirable in order to provide sufficient volume within the guide for the catheters and guides used for coronary procedures. 
         [0009]    Thus, an expandable sheath and system for intravascular insertion of a medical implement using the same solving the aforementioned problems is desired. 
       SUMMARY OF THE INVENTION 
       [0010]    The expandable sheath and system for intravascular insertion of a medical implement includes a cannula for entering a lumen of a vascular vessel of a patient, a guide wire insertable into the lumen, an introducer and dilator adapted to follow the guide wire into the lumen, an expandable sheath positioned on the introducer and dilator, with the expandable sheath being adapted to be positioned in the vessel, and an extension collar. The medical implement is received within the vessel by passing through the sheath upon separating the introducer and dilator therefrom. 
         [0011]    The expandable sheath is formed as an elongate flexible tubular member adapted for placement percutaneously within the vessel of the patient. The tubular member is preferably formed of a polymer material and includes a wall of substantially uniform thickness. The wall has an outer surface and an inner surface, with the wall having a first portion, a transitional portion and a second portion respectively having first, transitional and second inner diameters associated therewith. The first inner diameter is greater than the second inner diameter, and the transitional inner diameter is less than the first inner diameter and greater than the second inner diameter, such that, upon placement in the vessel, the sheath is adapted to slidably receive intravascular devices therein. In one embodiment, the tubular member includes a linear array of perforations formed therethrough, with the linear array of perforations extending from the second portion to the transitional portion, such that the linear array of perforations allow the second and transitional portions to expand. 
         [0012]    These and other features of the present invention will become readily apparent upon further review of the following specification and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a perspective view of an expandable sheath and system for intravascular insertion of a medical implement using the same according to the present invention. 
           [0014]      FIG. 2  is a partially exploded perspective view of an expandable sheath and system for intravascular insertion of a medical implement using the same according to the present invention. 
           [0015]      FIG. 3  is a further partially exploded perspective view of an expandable sheath and system for intravascular insertion of a medical implement using the same according to the present invention. 
           [0016]      FIG. 4  is a perspective view of the expandable sheath and system for intravascular insertion of a medical implement using the same. 
           [0017]      FIG. 5A  is an elevational view of an alternative embodiment of the expandable sheath and system for intravascular insertion of a medical implement using the same. 
           [0018]      FIG. 5B  is an enlarged view of the portion  5 B of the expandable sheath and system for intravascular insertion of a medical implement using the same of  FIG. 5A . 
           [0019]      FIG. 5C  is an enlarged view of the portion  5 C of the expandable sheath and system for intravascular insertion of a medical implement using the same of  FIG. 5A . 
           [0020]      FIG. 6A  is an elevational view of another alternative embodiment of the expandable sheath and system for intravascular insertion of a medical implement using the same. 
           [0021]      FIG. 6B  is cross-sectional view taken alone sectional cut line  6 B- 6 B of  FIG. 6A . 
           [0022]      FIG. 7  illustrates a kit including the expandable sheath and system for intravascular insertion of a medical implement using the same. 
           [0023]      FIG. 8  illustrates the kit of  FIG. 7  provided in sterile packaging. 
       
    
    
       [0024]    Similar reference characters denote corresponding features consistently throughout the attached drawings. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0025]    The expandable sheath and system for intravascular insertion of a medical implement, as shown in  FIG. 1 , generally identified as  10 , includes an introducer and dilator  62  having a proximal end  74 , a collar  76 , a sheath  40 , and a hub  60 . The sheath  40  has a proximal end  42 , a transitional area  46 , and a distal end  44 . The sheath is shown disposed about the introducer and dilator  62 , with the distal end  92  of introducer and dilator  62  shown extending from the distal end  44  of sheath  40 . The hub  60  may include, or be connected with, vascular procedural specific components, such as a hemostasis valve, for example. 
         [0026]    As shown in  FIGS. 1-3 , the overall length of the system  10  is segmented into five general regions. Each region has a specific geometrical form, and function, discussed below. Section  100  represents the distal end  92  of introducer and dilator  62 , section  110  includes the portion  94  of the introducer and dilator  62  (as shown in  FIG. 3 ), upon which the distal end  44  of sheath  40  is mounted. Section  120  represents the transitional portion  95  of introducer and dilator  62 , and the corresponding transitional section of  46  of sheath  40 . Section  130  includes a part of portion  96  of introducer and dilator  62 , and the proximal end  42  of the sheath, and hub  60  (connected to the proximal end  42 ). Section  140 , includes the remaining portion  96  of the introducer and dilator  62 , along with an extension collar  76 . 
         [0027]    As shown in  FIGS. 7 and 8 , a cannula  70  and guide wire  72  are provided for introduction into the lumen of a vascular member. Initially, the cannula  70  is used to puncture the skin, tissue, and vascular vessel, penetrating into the lumen. The guide wire  72  is subsequently introduced via the cannula  70  into the vessel, and remains traversing the skin, tissue, and vessel wall upon removal of the cannula  70 . The system  10  is thusly placed about the guide wire  72  (via the hollow interior of the introducer and dilator  62 ), and extended into the vessel lumen. The distal end  92  of the introducer and dilator  62  is tapered so as to gradually enter the aperture produced by the cannula  70 , increasing the aperture as the introducer and dilator  62  proceeds into the lumen. As best shown in  FIG. 2 , the distal end of the sheath  44  includes a tapered or rounded tip  54  that follows the distal end  92  of the introducer and dilator  62 , gradually increasing the size of the aperture leading into the vessel without causing any undue harm or injury to the skin, tissue, and vessel. 
         [0028]    The proximal end  42  of the sheath  40  may be color coded, or have indicia markings to indicate orientation and depth of penetration into the vessel. Once the desired penetration depth has been achieved, the introducer and dilator  62  is removed, and another implement, such as a catheter, for example, may be inserted into the vessel via the sheath  40 . The characteristics of the sheath  40  allow the catheter to enter into the vessel without causing any undue harm or injury to the vessel. The sheath  40  has, at its proximal end  42 , a first inner diameter, and at its distal end  42  a second inner diameter. 
         [0029]    Generally, the first inner diameter is larger than the second inner diameter. For example, the first inner diameter may be 8 Fr., while the second inner diameter may be 6 Fr. Between the proximal end  42  and the distal end  44  is a gradual transitional section  46  that connects the first inner diameter to the second inner diameter through a smooth, decrease in radial direction. This allows, for example, a gradual sloping from the 8 Fr. to the 6 Fr. inner diameters of the sheath  40 . The hub  60 , also has an inner diameter of 8 Fr. in alignment with the inner diameter of the proximal end  42  of sheath  40 . In operation, a medical practitioner is able to safely insert a medical implement, such as a balloon catheter of 6 Fr. diameter into the vessel via the sheath  40 . 
         [0030]    The introducer and dilator  62  has corresponding outer diameters with the inner diameters of the sheath  40 , in accordance with the sections  100 - 140  discussed above. Beginning from the tapered distal end  92  of introducer and dilator  62 , segment  110 , or portion  94 , has an outer diameter equal to the inner diameter of distal end  44  of sheath  40 , for example, 6 Fr. The outer diameter of the transition segment  120 , or portion  95 , of introducer and dilator  62  matches the inner diameter of transition section  46  of sheath  40 . Likewise, the outer diameter of segment  130 , or portion  96 , of introducer and dilator  62  is equal to the inner diameter of proximal end  42  of sheath  40 . 
         [0031]    Situated about the extension of portion  96  is collar  76 . Collar  76  has a first end  77  that matingly engages the hub  60  of sheath  40 . As shown in  FIG. 3 , collar  76  has a second end  78  that forms a stop for the end piece  74  of introducer and dilator  62 . The collar  76  prevents the introducer and dilator  62  from being inserted further into the sheath  40  than the depth of penetration indicia of the sheath requires. More importantly, this is the case when medical implements, such as catheters having maximum diameters of 6 Fr., are being used for vascular procedures. Collar  76  preferably releasably locks with both end piece  74  of introducer and dilator  62  and with sheath hub  60 . It should be understood that any suitable type of locking mechanism or releasable connector may be utilized. As an alternative, collar  76  may be replaced by a peel-away or tear-away collar, thus saving time in the conventional procedure, in which the dilator is removed, the collar is then removed, and then the dilator is re-inserted. 
         [0032]    If the need arises for medical implements having a greater diameter, such as 7 Fr. or 8 Fr., for example, conventional prior art systems require a different sheath to be inserted, which requires the removal of the first sheath, possibly causing blood loss and other injury to the vessel and surrounding tissue. The sheath  40 , however, avoids delay in catheter insertion due to repenetration of the introducer and dilator  62  and sheath  40 . Sheath  40  includes structure that allows for the expansion of the second inner diameter, as well as the transitional diameter, so that the inner diameter of the sheath  40  is uniformly the same as the first inner diameter of the proximal end  42 . 
         [0033]    In the alternative embodiment of  FIGS. 5A-5C , sheath  40  has a linear array of perforations  50  formed therethrough. The perforations  50  extend from transition section  46  to near the tip of distal end  44 . As best shown in the enlarged views of  FIGS. 5B and 5C , the perforations  50  are preferably linear, with each perforation  50  being separated from the adjacent perforation by a segment  52 . The perforations  50  begin at the tip  54  without breaching the open end of distal end  44  (see  FIG. 5B ). Likewise, the perforations  50  end near the junction of the proximal end  42  and transition portion  46 , such that that a space  48  prevents the perforations from encroaching into the proximal end  44 . It should be understood that the linear perforations are shown for exemplary purposes only, and that the perforations may have any desired contouring and relative dimensions, such as circular, elliptical, etc. Additionally, as best shown in the comparison between  FIGS. 5B and 5C , the perforations  50  toward the distal end of the sheath  40  are preferably longer to allow for less resistance while introducing the larger portion of the dilator and to expand the sheath with less force. 
         [0034]    In the embodiment of  FIGS. 6A and 6B  (taken along direction  6 B- 6 B of  FIG. 6A ), the sheath  40  may be an elongated cylindrical tube having a large diameter portion  12  at the proximal end thereof (for example, with an inner diameter of 8 Fr.) with an elongated slit  16  extending longitudinally from the distal end of the sheath towards the large diameter portion. It will be understood that the slit  16  may extend for more than one-half the length of the sheath  40 , and may extend up to 80-90% of the length of the sheath  40 , extending from the smaller diameter portion  14  of sheath  40  (having a diameter of 6 Fr., for example). The slit  16  may be formed by any suitable method, such as, for example, by using a circular blade with grooves. When such a blade is rolled on the sheath, the grooves leave non-slit portions between the slits created by the circular blade. The slit portion  16  is preferably formed so that the edges of the slit are harmless to the arterial wall. In the formation example given above, the way the blade edges are formed, the sharp edges of the blade slit the tube and the slit edges are compressed by the non-sharpened edges and form non-traumatic edges on both sides of slit. 
         [0035]    The slit  16  in portion  14  is kept tight to prevent bleeding. The slit  16  must avoid bleeding when sheath  40  is introduced into the artery and is used within its original dimensions (i.e., non-expanded) to deliver catheterization tools with the outside diameter smaller than the inner original diameter (i.e., non-expanded) of the sheath. Additionally, as shown in  FIG. 6B , indicia  18  may also be formed on the sheath  40  to indicate orientation, penetration depth, and any other desired positional characteristic of the sheath  40 . Indicia  18  may include markings, etchings, arrows, and/or color-coding along the entire length of sheath  40 . Indicia  18  preferably is formed on the proximal end  42 , so as to extend outside the radial artery (upon insertion), away from the patient. As an alternative to the pre-formed perforations  50  of  FIGS. 5A-5C  or the pre-formed external slit  16  of  FIGS. 6A and 6B , the dilator could be provided with a blade or the like for creating a continuous internal slit as the sheath  40  is inserted thereon. Such a blade or the like mounted on dilator  78 , preferably between sections  110  and  120 , would create an internal slit, allowing for expansion as described above with regard to both perforations  50  and external slit  16 . 
         [0036]    The purpose of the perforations  50  ( FIGS. 5A-C ) and slit  16  ( FIGS. 6A and 6B ) is to provide the medical practitioner with the ability to utilize a single system for multiple sized catheters during an intravascular procedure. The sheath  40  in both embodiments is expandable, thus increasing the second inner diameter and the transitional diameter to match the first inner diameter; i.e., expanding the transition section  46  and distal end  44  so that the respective inner diameters match the larger inner diameter of the proximal end  44 . In the example described above, the 6 Fr. distal diameter is expanded to match the 8 Fr. proximal diameter. 
         [0037]    As best shown in  FIGS. 3 and 4 , after the system  10  has been inserted into a vessel, the introducer and dilator  62  is withdrawn from sheath  40 , the extension collar  76  is removed by disengaging the first end  77  from the hub  60 . The introducer and dilator  62  is reinserted into the sheath  40  via hub  60 , and is extended along the length of the segment  140  (i.e., the remaining part of portion  96 ). Upon reinsertion, the transitional portion  95  of introducer and dilator  62  forces the transitional section  46  and distal end  44  of sheath  40  radially outward so that the inner diameter is consistent throughout the sheath  40 . The proximal end portion  96  of the introducer and dilator  62  has an outer diameter equal to the inner diameter of proximal end of the sheath  40 , thus maintaining the expansion until the introducer and dilator  62  has traveled the full extent of the length through the five segments  100 ,  110 ,  120 ,  130 ,  140 . 
         [0038]    As shown in  FIG. 4 , the sheath  40  has a constant diameter externally, indicative of the internal diameter also being constant. In this particular example, the inner diameter has been expanded to 8 Fr., thereby allowing the medical practitioner to utilize implements that are greater than 6 Fr. in the sheath  40 . Once the introducer and dilator  62  is removed, the expanded sheath allows the larger diameter implements to be inserted into the vascular vessel. Further, it is clear that the introducer and dilator  62  is a single element used in the system for both guiding the sheath  40  into the vessel, as well as causing the sheath  40  to be expanded. 
         [0039]    Additionally, the first end  77  of collar  76  is designed and configured to matingly engage the hub  60  of sheath  40 . The mating engagement may be accomplished in any suitable manner, including, but not limited to, friction fit, threads, twist lock, key and channel, dovetail, etc. Likewise, the second end  78  of the collar  76 , which stops the forward progression of the introducer and dilator  62  into the sheath  40 , may also be a mating engagement, similar to the first end and  77  with hub  60 , forming an abutment for the end  74  to stop against. 
         [0040]    In the embodiment of  FIGS. 5A-C , sheath  40  may be made from any suitable polymer or plastic material that has sufficient plasticity so that, upon the expansion of the perforations  50 , the sections  52  will stretch to accommodate the larger diameter, but upon removal of the introducer and dilator  62 , sections  52  will not return to the original shape. Similarly, the sheath  40  in  FIGS. 6A and 6B , upon insertion of the introducer and dilator  62 , causing the seam to split along the slit  16  and expand to accommodate larger implements inserted through the sheath  40 , the sheath  40  will retain its shape with the slit  16  opened. The sheath  40  may made from a single, homogenous layer of material. It should be understood that the contouring and relative dimensions of both slit  16  and perforations  50  may be varied, and those shown have been shown for exemplary purposes and for purposes of clarity only. 
         [0041]    Referring to  FIGS. 7 and 8 , the sheath  40  is part of a complete system  68  for introducing medical implements into the vascular system of a patient. The complete system  68  includes, as shown in  FIG. 7 , a holder, such as holster  64 , an introductory cannula  70 , a guide wire  72 , the expandable sheath  40 , and a stepped dilator  74 . The holster  64  includes a mount  76  for supporting the complete system  68  in proximity to the patient during installation into a blood vessel. The complete system  68  may be provided in packaging  80 , as shown in  FIG. 8 , so as to be completely sterile when needed. The packaging  80  has an indicator  84  for identifying that the contents, namely the complete system  68  and its components, are sterile. The package also has a label  82  with indicia for identifying the contents, as well as instructions on usage, warnings, and dates of manufacture, use by, and/or expiration. 
         [0042]    It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.