Abstract:
Leading edges of concentric members are desirably hidden in unions of two concentric members intended for advancement through the vasculature for vasculature implant delivery. Grooves or impressions on the inner concentric member provide spaces for the leading edge of the distal tip of the outer concentric member to create edgeless unions of two concentric members for safe and unimpeded advancement and operation of vascular implant delivery devices which include the two concentric members.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present non-provisional application claims under 35 U.S.C. §119(e) the benefit of priority of U.S. Provisional Application Ser. No. 61/542,151, filed Sep. 30, 2011, and entitled “Edgelesss Unions of Concentric Members,” the contents of which is expressly incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The invention relates to the field of medical devices, and more particularly a vascular implant delivery system. 
         [0004]    2. Related Devices and Methods 
         [0005]    Vascular disease is a leading cause of premature mortality in developed nations. Treatment of vascular disease may include implantation of tissue supporting stents or prosthetic vasculature, e.g., grafts, stent-grafts, etc., which are delivered through the vasculature at a reduced dimension for ease of navigation in, and reduced chance of injury to, the tortuous vasculature from entry point to the diseased location. These vascular implant delivery devices typically include an elongated shaft around which the vascular implant is disposed at a distal end, that is the end furthest from the medical professional implanting the vascular implant. Such shafts may have variable designs as best suited to deliver the vascular implant from the point of entry to the vasculature to the intended implantation site. Some delivery devices further include additional features such as soft tips on the distal ends of the elongated shafts, sheaths or outer members disposed about much of the length of the elongated shaft and about the vascular implant, and various features on the proximal end, that is, the end closest to the medical professional to perform varied functions, e.g., release of dye or other visualization agent, valved access to a lumen running through the elongated shaft for inserting a guide wire, sealed attachment of a pressurized fluid to inflate balloons at the distal end, or other mechanisms involved in the controlled delivery of the vasculature to its intended site. Unless otherwise stated, the other variations in the construction of the medical device to which the present invention is coupled or is otherwise a physical part of are not germane to the present invention. 
         [0006]    It is desirable to have a smooth transition at any union of two concentric members, such as at the tip of inner and outer members of vascular implant delivery systems, that is expected to interact with the patient&#39;s vasculature to prevent inadvertent injury to the vessel from insertion and tracking of the device to the target location. Such interactions with the vessel wall can cause vessel spasm, damage to health intima or even vessel perforation or dissection. 
         [0007]    Secondly any edge created by such a union might be a liability for any procedure that introduces more than one stent or stent-graft. After delivery of the first implant, the delivery system of the second implant is required to be inserted in to the lumen of the deployed implant to create an overlap. Upon introduction of the second delivery system any edge on the delivery system that is exposed can potentially snag on the deployed first implant. Unintended interactions, such as snagging, may cause problems with the placement of the first implant, interaction of the first implant and the vessel wall or fatigue of the first implant itself 
       SUMMARY 
       [0008]    In some embodiment according to the invention, grooves or impressions made in the outer surface of an inner member of two concentric member hides the leading edge of the tip of the outer concentric member allowing for a more continuous unified transition. These grooves or impression may be angled to match the outer tip design or may be generic grooves that are intended just to hide the edge of the outer tip. There can be a single groove or there could also be more than one groove. 
         [0009]    These and other features, benefits, and advantages of the present invention will be made apparent with reference to the following detailed description, appended claims, and accompanying figures, wherein like reference numerals refer to structures that are either the same structures, or perform the same functions as other structures, across the several views. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES: 
         [0010]    The figures are merely exemplary and are not meant to limit the present invention. 
           [0011]      FIG. 1A  is a top view of an inner member, near the distal tip. 
           [0012]      FIG. 1B  is a cross-sectional view of the inner member of  FIG. 1A . 
           [0013]      FIG. 2  is a top view of the inner member of  FIG. 1A  assembled with a concentric outer member, showing the union of the distal tip of the concentric outer member with the inner member. 
           [0014]      FIG. 3  is a cross sectional view of an enlarged portion of the assembly of  FIG. 2 . 
           [0015]      FIG. 4A  is a top view of a three dimensional rendering of a distal portion and tip of an inner member with a second embodiment of grooves. 
           [0016]      FIG. 4B  is a top view of an enlarge portion of  FIG. 4A . 
           [0017]      FIG. 5A  is a top view of the inner member of  FIG. 3  assembled with a concentric outer member, showing the union of the distal tip of the concentric outer member with the inner member. 
           [0018]      FIG. 5B  is a cross-sectional view of an enlarged portion of the assembly of  FIG. 5A . 
           [0019]      FIG. 6A  is a top view of an assembly of yet a third inner member, without circumferential grooves, assembled with another embodiment of an outer concentric member, showing the union of the distal tip of the concentric outer member with the inner member. 
           [0020]      FIG. 6B  is an enlargement of a portion of  FIG. 6A . 
           [0021]      FIG. 6C  is a cross section of an enlarged portion of  FIG. 6A . 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    An edgeless union of two concentric members is a feature that is designed to be used where two tips (an inner and outer member) come together and form a union. Without the benefit of embodiments of this invention, a solid tubular inner tip would have a tip of a concentric outer member resting on its outer groove-less surface creating a bump/step transition, such as depicted in  FIGS. 6A ,  6 B, and  6 C, that can lead to tissue damage and/or procedural issues due to the tip of the concentric outer member snagging. 
         [0023]    Edgeless unions of concentric members may include grooves, such as those depicted on inner member in  FIGS. 1A-1B  and  4 A- 4 B to hide the edge of the tip of the concentric outer member allowing for a more continuous, unified transition, as depicted in  FIGS. 2 ,  3 , and  5 A- 5 B instead of the bump or step transition. In some embodiments, grooves may be angled to match the outer tip design, such as depicted in  FIGS. 1A-3 , or may be generic grooves, such as those depicted in  FIGS. 4A-5B , that are intended just to hide the edge of the tip of the outer concentric member. In some embodiments there is a single groove. In some embodiments, more than one groove can be included to provide a length of the inner member along which the edge of the concentric outer member will “land” upon final assembly, taking into account length tolerances of the inner and outer concentric members. 
         [0024]    In some embodiments, the depth, width (longitudinal length) and angle of these grooves are enough to allow hiding of the edge but still allow for linear retraction of the inner member back through the concentric outer member. 
         [0025]    One embodiment is illustrated in  FIGS. 6A through 6C  where the leading edge of the outer member is given a radius. However, this embodiment fails to hide the edge and just simply attempts to make the edge less sharp. 
         [0026]    A second embodiment is illustrated in  FIGS. 6A-6C  includes drawing down the diameter of the tip of the concentric outer member. This embodiment puts a taper on some distal portion of the outer member in an attempt to have an angle of transition to the outer member body. This embodiment works well for preventing of “fish mouthing” (a condition of the outer member becoming oval and gapping on opposite sides, resembling an open fish mouth) because of tight conformance of the outer member to the inner member and does provide an angle of transition instead of a true step transition. However this taper does not hide the edge that is created going from a smaller diameter of the outer diameter of the inner member to the larger diameter of the inner diameter of the concentric outer member on it. 
         [0027]    Yet another embodiment of an edgeless union is an inner member with a smaller outer diameter on the proximal end and a larger outer diameter on the distal end (much like an arrow) to essentially create a plug when inserted into the outer member. However, in these embodiments, the tip of the concentric inner member is not made to be withdrawn back through the concentric outer member; it would not be able to be retracted back due to large sharp change in diameter. 
         [0028]    Other embodiment of edgeless unions of concentric members has impressions (circumferential angulated or non angulated impressions) in the outer surface of the inner member that will allow the concentric outer member to conform to it, thereby hiding the edge while still achieving a tight conformance to the inner member and allowing the retraction of the inner member back through the outer. It is counterintuitive that impressions are put onto the inner member tip making it less smooth in order to achieve a smoother transition as an assembly when mated with the outer member. In some embodiments, one circumferential angulated or non angulated impression will be on the inner concentric member. In some embodiments, any number of circumferential angulated or non angulated impressions may be made in the inner concentric member to allow easier assembly in manufacturing. 
         [0029]    Embodiments including the impressions on the inner member could also allow physicians the ability to initiate deployment, decide to abort deployment to reposition or retract completely. In doing so the physician would just retract to the next impression which would ensure the edge is hidden and the physician may maneuver the delivery system with the same performance as he or she did during initial insertion. 
         [0030]      FIG. 1A  is a top view of an inner member  100 , near the distal tip (not shown). Inner member  100  has an outer diameter with a cylindrical outer surface  102  in which three circumferential grooves  104  are formed. Each groove  104  has two opposing tapered faces, tapered face  106  with a decreasing diameter along the proximal to distal length, and tapered face  108  with an increasing diameter along the proximal to distal length. The tapered face  108  has a much steeper taper, such that the groove is not symmetric. 
         [0031]      FIG. 1B  is a cross-sectional view of the inner member of  FIG. 1A . It may be seen that in this embodiment, inner member  100  has a lumen  110  therethrough. 
         [0032]      FIG. 2  is a top view of inner member  100  of  FIG. 1A  assembled (assembly  200 ) with a concentric outer member  202 , showing the union of distal tip  204  of concentric outer member  202  with inner member  100 . It may be seen that distal tip  204  is hidden within the second of the three grooves  104 . 
         [0033]      FIG. 3  is a cross sectional view of an enlarged portion of the assembly of  FIG. 2 , and illustrates the leading edge of distal tip  204  within groove  104 , resulting in an edgeless union of two concentric members. 
         [0034]      FIG. 4A  is a top view of a three dimensional rendering of a distal portion and tip  126  of an inner member  120  with a second embodiment of grooves  124  in outer cylindrical surface  122  of inner member  120 . Inner member  120  has three circumferential grooves in this embodiment, spaced unevenly along the longitudinal length. 
         [0035]      FIG. 4B  is a top view of an enlarge portion of  FIG. 4A  illustrating that grooves  124  have two opposing tapered faces  128  and  130 . The taper of tapered face  128  is an increasing diameter in the distal direction and the taper of tapered face  130  is a decreasing diameter in the distal direction, and the tapers are the same, such that the groove  124  is symmetric. 
         [0036]      FIG. 5A  is a top view of the inner member  120  of  FIG. 3  assembled (assembly  220 ) with a concentric outer member  222 , showing the union of the distal tip  224  of the concentric outer member  222  with the second groove  124  of inner member  120 . 
         [0037]      FIG. 5B  is a cross-sectional view of an enlarged portion of the assembly of  FIG. 5A , which illustrates that inner member  120  has a lumen  226  therethrough. 
         [0038]      FIG. 6A  is a top view of an assembly  230  of yet a third inner member  130 , without circumferential grooves, assembled with another embodiment of an outer concentric member  232 , showing the union of the distal tip  234  of the concentric outer member  232  with outer cylindrical surface  132  of the inner member  130 . 
         [0039]      FIG. 6B  is an enlargement of a portion of  FIG. 6A  illustrating the tapered distal tip  234  ending in an exposed leading edge  236 . 
         [0040]      FIG. 6C  is a cross section of an enlarged portion of  FIG. 6A  illustrating that in this embodiment, inner member  130  has a lumen  238  therethrough and the step or bump transition presented by the leading edge of the tapered distal tip  234  of outer concentric member  232 . 
         [0041]    Aspects of the present invention have been described herein with reference to certain exemplary or preferred embodiments. These embodiments are offered as merely illustrative, not limiting, of the scope of the present invention. Certain alterations or modifications possible include the substitution of selected features from one embodiment to another, the combination of selected features from more than one embodiment, and the elimination of certain features of described embodiments. Other alterations or modifications may be apparent to those skilled in the art in light of instant disclosure without departing from the spirit or scope of the present invention, which is defined solely with reference to the following appended claims.