Abstract:
A venous access device comprises a catheter portion extending longitudinally from a proximal end to a distal end, the flexible shaft defining a lumen therein in combination with a plurality of branches separated from one another and extending distally from the flexible shaft.

Description:
BACKGROUND 
       [0001]    Venous access devices (VADs) include ports and indwelling catheters such as peripherally inserted central catheters (PICCs) that include flexible tubes used to supply fluids to internal body structures (e.g., nutrients, medications, blood products, etc.) over extended periods of time. Indwelling catheters may also be used to aspirate fluids such as blood from the patient for diagnostic procedures or to drain fluids for other therapeutic purposes. An indwelling catheter may, for example, include a proximal portion extending outside the skin or inside a pocket under the skin, while a distal tip extends through the body often along a tortuous path to enter a target body structure—e.g., the superior vena cava. To reduce trauma to tissue along this path, indwelling catheters are often made smaller in diameter, resulting in reduced flow rates. Additionally, the implanted portion of the catheter may be susceptible to fibrin sheath adherence and encrustation, which may reduce the mobility of the implanted portion. 
       SUMMARY OF THE INVENTION 
       [0002]    The present invention is directed to venous access devices that include branches at the distal end to enhance device flexibility and to minimize the risk of fibrin sheath adherence and encrustation by blood or other bodily fluids. 
         [0003]    In one embodiment, the present invention is a venous access device that comprises a catheter portion extending longitudinally from a proximal end to a distal end. The catheter portion includes a first lumen extending in a proximal portion thereof. At its distal end, the device comprises a plurality of branches separated from one another and extending distally from the catheter proximal portion. Each of the plurality of branches includes a lumen that extends between the lumen that extends within the proximal portion of the catheter portion, and a distal end that opens to an exterior of the device. 
         [0004]    In another embodiment, the present invention is a venous access device that comprises a multi-lumen catheter portion extending longitudinally from a proximal end to a distal end. The catheter portion includes a plurality of lumens, each extending in a proximal portion thereof. At its distal end, the device divides into sections, with each section containing at least one of the plurality of lumens, and each section further comprising a plurality of branches separated from one another and extending distally therefrom. Each of the plurality of branches includes a lumen that extends between the lumen(s) that extends within each section and a distal end that opens to an exterior of the device. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  shows a perspective view of a venous access device according to an exemplary embodiment of the present invention; 
           [0006]      FIG. 2  shows a cross-sectional view of the system of  FIG. 1 , along line A-A. 
           [0007]      FIG. 3  shows a cross-sectional view of the system of  FIG. 1 , along line B-B. 
           [0008]      FIG. 4  shows a cross-sectional view of the system of  FIG. 1 , along line B-B, according town alternate embodiment of the present invention. 
           [0009]      FIG. 5  shows a perspective view of a venous access device according to an exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    The present invention may be further understood with reference to the following description and the appended drawings, wherein like elements are referred to with the same reference numerals. The present invention relates to devices for the transfer of fluids to and from a target structure within a patient&#39;s body over an extended period of time. In particular, exemplary embodiments of the present invention describe a venous access device that includes a branched distal tip for improved mobility, flexibility and flow. 
         [0011]    As shown in  FIGS. 1-3 , a venous access device  100  according to an exemplary embodiment of the present invention comprises an indwelling catheter portion  102  a proximal end  108  of which is connected to a port device  104 . It will be understood by those of skill in the art that, although the device  100  is described as a port catheter system with a port device  104 , the device  100  may be any venous access device, such as PICCs, central venous catheters (CVCs), dialysis catheters, and midline infusion catheters. For example, the catheter portion  102  may extend out of the skin to any known port connectable to external devices as desired and which may be sealed between uses such as, for example, a drainage bag for a drainage catheter system. 
         [0012]    As shown in  FIG. 1 , the catheter portion  102  includes a shaft  106  extending from the proximal end  108  to a distal end  110  which, in an operative position, is inserted into a target structure within a patient&#39;s body. A proximal portion  118  of the shaft  106  includes a single first lumen  114  extending therethrough. A thickness  115  of a wall  117  of the shaft  106  around a circumference thereof may be selected as would be understood by those of skill in the art to achieve the desired properties (e.g., burst strength, flexibility, etc.) while the first lumen  114  is shaped to maximize its cross-sectional area without compromising these properties. At a distal end  110 , the shaft  106  splits into a plurality of branches  112  at which the first lumen  114  opens to two lumens  116  each of which extends through a corresponding one of the branches  112 . In a preferred embodiment, an outer diameter of each of the plurality of branches  112  is smaller than an outer diameter of the proximal portion  118  of the shaft  106 . In alternate embodiments, each branch  112  has substantially the same diameter or greater diameters as compared to that of the proximal portion  118 . In yet other embodiments, each branch  112  has a different size (e.g., length and/or diameter) from other branches, and/or a different cross sectional configuration (e.g., round, oval, trapezoid, D-shaped, etc.) from other branches. In a preferred embodiment, the shaft  106  splits into two branches  112 , although it will be understood by those of skill in the art that the shaft  106  may split into any number of branches  112 .  FIG. 3  shows an embodiment of the catheter portion  102  in which the cross-section of lumens  116  are substantially D-shaped in the same manner as a lumen of a standard dual-lumen catheter. However, as shown in  FIG. 4 , either or both of the lumens  116  may be substantially round. 
         [0013]    In another embodiment as shown in  FIG. 5 , the venous access device of the present invention includes a dual-lumen catheter portion  102 . Such dual-lumen devices are known in the art, and include devices such as dual-lumen ports (as shown in  FIG. 5 ), PICCs, and other implantable devices that include separate lumens that can be used to deliver different or the same materials such as therapeutic agents or contrast agents, or can be used to aspirate blood or other bodily fluids. In accordance with the present invention, the catheter portion  102  is divided into two sections  150 ,  151  at the distal end  110 , with each section including one of the lumens that extend from the proximal end  108  to distal end  110 . Each such section  150  is thereafter split into multiple branches  112  as described with reference to  FIGS. 1-4 , above. 
         [0014]    The inventors have found that the use of branches  112  enhance the mobility and flexibility of the indwelling portion of the catheter portion  102  as compared to a single tube catheter. For example, in embodiments where the outer diameter of each of the branches  112  is smaller than the outer diameter of the proximal portion  118 , it will be understood by those of skill in the art that the distal end  110  of the device is more flexible than the proximal portion  118 . This enhanced flexibility allows for greater movement of the device  100  at its distal end  110  while implanted, such as with normal cardiovascular flow and pulse. The added flexibility and motion of the branches  112  inhibits fibrin sheath adherence and encrustation by blood or other bodily fluids, as sometimes encountered with single tube catheters. 
         [0015]    In use, fluid flowing distally through the first lumen  114  splits into the lumens  116  as it leaves the proximal portion  118  and enters the distal end  110  of the device  100 . In one embodiment, one or all of the lumens  116  taper toward the distal end  110  (i.e., a cross-sectional area of the lumen may grow gradually smaller from the proximal end of the corresponding branch  112  toward the distal end thereof). In addition, any or all of the branches  112  may be angled relative to one another, depending upon a desired performance aspect. That is, longitudinal axes of the branches  112  may be set at any desired angle relative to a longitudinal axis of a distal end of the proximal portion of the shaft  106  to achieve a desired orientation of the branches  112  relative to one another. Preferably, this angle is minimized to between 0 and 45 degrees, and more preferably between 0 and 15 degrees, such that the branches are in-line with the catheter longitudinal axis. As an example, the proximal portion  118  near the distal end  110  can define a first longitudinal axis and the first and second branches  112  can define second and third longitudinal axes, respectively. The a preferred embodiment, the second axis extends at an angle of less than 45 degrees from the first axis and the third axis is substantially co-axial with the first axis. 
         [0016]    Those skilled in the art will understand that, for a catheter portion  102  including more than two branches  112 , the various branches  112  may be located in a single plane or a plurality of planes. The length of each branch is preferably less than about eight centimeters from most venous access applications. 
         [0017]    The distal end  110 , including the branches  112  may be delivered to a target area of the body in the same manner used for conventional split tip catheters as will be understood by those skilled in the art. The branches  112  may be temporarily bonded to one another or held together by an insertion device to facilitate the passage of the catheter portion  102  through intervening tissue with a minimum of trauma thereto. 
         [0018]    It will be understood by those skilled in the art that a catheter according to the present invention may include multiple lumens through a proximal part thereof so long as at least one of these proximal lumens opens to a plurality of lumens in separate distal branches of the catheter. That is, a catheter having a proximal part including two lumens will include at least three branches at a distal end thereof with each branch including a lumen open to one or more of the lumens of the proximal part. 
         [0019]    It will be apparent to those skilled in the art that various modifications and variations can be made in the structure and methodology of the present invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided that they come within the scope of the appended claims and their equivalents.