Abstract:
A hemostasis valve which has a varying diameter. The hemostasis valve is actuated by a mechanism which provides mechanical advantage. Actuation of the hemostatis valve provides selective incremental sizing such that the valve will fit a variety of different intravascular devices.

Description:
This application claims priority to U.S. Provisional Patent Application Ser. No. 60/105,384, filed Oct. 23, 1998. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to the field of minimally invasive medicine. More particularly, the present invention relates to those devices, commonly known as y-adapters, which are used to prevent blood from exiting a patient during a minimally invasive procedure. Such procedures include but are not limited to angioplasty, atherectomy, stenting, angiography, venous filtration, liquid infusion, dialysis, and intravascular ultrasound. Those skilled in the art will recognize the benefits of applying the present invention to similar fields not discussed herein. 
     BACKGROUND OF THE INVENTION 
     Angioplasty has gained wide acceptance in recent years as an efficient and effective method for treating various types of vascular diseases. In particular, angioplasty is widely used for opening stenoses in the coronary arteries, although it is also used for treatment of stenoses in other parts of the vascular system. The most widely used form of angioplasty makes use of a guide catheter positioned within the vascular system of a patient. The distal end of the guide catheter is inserted into an introducer sheath which is then inserted into the femoral artery located in the groin of the patient and pushed distally up through the vascular system until the distal end of the guide catheter is located in the ostium of the coronary artery. The distal end of the guide catheter is normally curved so that the distal tip of the guide catheter is more easily directed to the coronary ostium of the patient. Typically, a Y-adapter assembly is releasably secured to the proximal end of the guide catheter. The proximal end of the guide catheter and the Y-adapter protrude outside the patient&#39;s body. The Y-adapter provides an entryway for subsequent insertion of additional angioplasty devices into the patient&#39;s vascular system through the guide catheter. Prior art Y-adapters typically includes a main body portion that is secured at its distal end to the guide catheter via a luer fitting. The Y-adapter further includes a side branch that defines an infusion port. The main body portion of the Y-adapter is configured to receive a dilatation balloon catheter. 
     The proximal end of the side branch and the main body portion typically include valves which are known as Tuohy-Borst valves. Tuohy-Borst valves are seals that minimize back-bleeding during the minimally invasive procedure. Each Tuohy-Borst seal includes a gasket having a through lumen and a threadably attached cap. The through lumen is configured to receive a shaft of a dilatation catheter or other minimally invasive device. The cap can be rotatably tightened to compress the gasket and thereby decrease the diameter of the through lumen to form a fluid tight seal about the shaft of the dilatation catheter. However, if the cap of the Tuohy-Borst seal is tightened too much, the dilatation catheter may be damaged or the flow of inflation fluid through the catheter may be restricted so as to make inflation of the balloon of the dilatation catheter difficult. On the other hand, tightening the cap too little may allow back-bleeding through the proximal ends of the side branch and the main body portion of the Y-adapter. 
     There is a continuing need for improved hemostasis and Y-adapters. Specifically, there is a need for a Y-adapter of efficient design which incorporates a valve member that provides an effective releasable seal about the shaft of a dilatation catheter and provides simplified physician use. The valve member would preferably provide a fluid tight seal about the dilatation catheter to prevent back-bleeding, while minimizing damage to the catheter. In addition, the seal formed by the vale member would not restrict the flow of inflation fluid through the dilatation catheter. It would also be advantageous to provide a valve member which may selectively seal about certain diameter devices while at the same time providing visual feedback as to diameter. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 depicts a y-adapter assembly which incorporates the present invention. 
     FIG. 2 is an exploded view of the assembly shown in FIG.  1 . 
     FIG. 3 is an enlarged side view of the cam depicted in FIG.  2 . 
     FIG. 4A is a partial side view the assembly of FIG. 1, where the valve is in the fully open position. 
     FIG. 4B is an enlarged partial side view the assembly of FIG.  4 A. 
     FIG. 4C is a partial side view the assembly of FIG. 4B where the valve is partially closed. 
     FIG. 4D is a partial side view the assembly of FIG. 4B where the valve is completely closed. 
     FIG. 5 is a depiction of an alternative y-adapter assembly which incorporates the present invention. 
     FIG. 6 is a depiction of another alternative y-adapter assembly which incorporates the present invention. 
     FIG. 7A is a side view of a valve. 
     FIG. 7B is an end view of the valve of FIG.  7 A. 
     FIG. 7C is a side view of an alternative valve. 
     FIG. 7D is an end view of the valve of FIG.  7 C. 
     FIG. 8 depicts an axially activated Y-adapter assembly. 
     FIG. 9 is an exploded view of the assembly shown in FIG.  8 . 
     FIG. 10 is a partial sectioned side view of FIG.  8 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following detailed description should be read with reference to the drawings in which like elements in different drawing are numbered identically. The drawings, which are not necessarily to scale, depict selected embodiments and are not intended to limit the scope of the invention. 
     Examples of constructions, materials, dimensions, and manufacturing processes are provided for selected elements. All other elements employ that which is known to those skilled in the field of the invention. Those skilled in the art will recognize that many of the examples provided have suitable alternatives that may also be used. 
     FIG. 1 depicts an embodiment of a y-adapter  50  with actuating button  51 . Actuating button  51  may be moved either proximally or distally with the thumb or forefinger and thereby actuate the opening or closing of y-adapter  50 . 
     FIG. 2 is an exploded view of y-adapter  50 . Actuating button  51  is designed to slide within  62  of distal housing  70 . Movement of button  51  actuates motion of cam  20 . Cam  20  is pinned to proximal housing  80  by pin  22 . Accordingly pin  22  defines the axis of rotation of cam  20 . 
     Follower surface  30  is integrally molded with cylinder  40  and serves to compress valve  53  when cylinder  40  is moved axially. Washers  60  may additionally be provided proximally and distally of valve  53 . Proximal housing  80  is bonded to body  90  and when brought into contact with distal housing  20 , encases cylinder  40 , cam  20 , valve  53  and washers  60 . 
     Valve  53  may preferably be formed of medical grade silicone such as Wacker R4000. The amount of force needed to compress valve  53  is dependent on the relative hardness of the material used for valve  53 . Accordingly, it may be desirable to provide a material for valve  53  that is 20-50 Shore A durometer. Preferably, the durometer of the material of valve  53  may be 30 Shore A. Lower durometer valves or valves with a cutout as shown in FIGS. 7A-D are examples of valves which require less compression to close valve lumen  62 . Cylindrical valves with cutouts provide reduced friction and thereby allow physicians to have better tactile feedback during a procedure. 
     Proximal housing  80 , distal housing  70 , cylinder  40  and body  90  may be formed of a suitable medical grade polymer. Preferably, proximal housing  80 , distal housing  70 , cylinder  40  and body  90  may be formed of polycarbonate. Button  51  may be formed of a medical grade acetal-copolymer such as Celcon, natural. 
     Detents  120  may be formed in proximal housing  70 . Detents  120  may be spaced at regular positions along the travel length of button  51  and require button  51  to click into positions which correspond with particular diameters of valve lumen  62 . Detents  120  may be conveniently positioned to correspond to atherectomy devices, stent catheters, balloon catheters and guide wire (8 Fr., 5 Fr., 3 Fr. and 0.014 inches respectively). Button  53  may also be moved rapidly such that the valve lumen  62  moves from completely open to completely closed. 
     In an alternative embodiment, button  51  may be designed such that specified positions along it travel length are indexed by radial teeth (not shown) which project from button  51  and mate with slots in proximal housing  70 . In yet another embodiment of button  51 , button  51  may have a spring mechanism which may include a coil spring or a leaf spring which maintains the button position but may also be depressed and allow the diameter of valve lumen  62  to be fine tuned. 
     FIG. 3 depicts cam  20  with button contact surface  29  and follower contact surface  25 . Mechanical advantage is gained by the moment arm  27  or the perpendicular distance from the point which the button  51  contacts button contact surface  29 , with varying force F, to the cam axis  23 . Moment arm  27  is a key factor in the amount of force required to actuate button  51  and compress valve  53 . The location of cam axis  23  and its position relative to the follower contact surface  25  also is a factor in the mechanical advantage provide by cam  20 . The ratio of the distance the button travels axially compared to the axial travel of the follower may be a factor of 3:1 or more depending on the size and design of the cam  20 . 
     To maintain a small profile, the cam  20  should be as small as possible. However, small cam sizes have fairly high stress and therefore require stronger materials of construction. In addition to polycarbonate and other suitable medical grade polymers, filled materials may be required to withstand the high stress. Suitable filled materials may include glass filled ABS or Celcon™. 
     As may be seen in FIGS. 4A-4D, the linear activation of button  51  rotates cam  20  about pin  22  while the cam contacts the follower surface  30 . The follower surface  30  slides the cylinder  40  axially and compresses valve  53  as a function of the contact between follower surface  30  and cam  20 . Compression of the valve  53  causes reduction in the lumen diameter of valve  53 . Preferably, valve  53  will be sized such that any device may be used. A total range for valve  53  may be 9.6-0 French or 0.125-0 inches. 
     Ergonomic designs of button  51  may include various shapes or sizes as well as being fully circumferential. These designs allow easy access irrespective of the position of the y-adapter. FIGS. 5 and 6 are examples of alternative button designs  51 . 
     In addition to the embodiments shown, a cylindrical activation surface which encompasses the total circumference of the valve may also be used and will allow for easy access from any angle. Axial adjustment may also include another mechanism which allows the user analog adjustment. Analog adjustment provides for fine tuning of the valve to the required amount of hemostasis and the appropriate feel or lumen size for the particular device within the y-adapter. One such method of achieving analog adjustment is through the addition of a cylindrical threaded surface which can be adjusted for fine tuning. 
     Mechanisms other than a cam design may also be employed to achieve the main objective of the invention. One such mechanism would provide pure axial translation to compress the valve  53 . FIG. 8 depicts this embodiment of a y-adapter  160  with a cylindrical actuating button, hereafter called a collar  161 . The cylindrical actuating collar  161  may be moved either proximally or distally with the thumb or forefingers and thereby actuate the opening or closing of the y-adapter. FIG. 9 is an exploded view of the assembly shown in FIG.  8 . Various lumen sizes would be achieved by axially sliding the collar  161  along the adjusting threads  162  to snap fit into certain positions. The partial sectioned side view in FIG. 10 shows how the snap fit would be achieved by axially located spring arms  164  located within the adjusting threads  162 . The spring arms deflect when forced to move axially and snap into the thread minor diameter in either direction to achieve closing or opening of the y-adapter lumen. Alternately, the collar  161  may be rotated to achieve fine tuning of the y-adapter lumen. A spring mechanism  163  would increase the ratio of manual motion to valve compression, thereby providing the physician with greater tactile feedback. The spring  163  actuates the cylindrical push rod  40  similar to that found in the embodiment of FIG.  2 . The pushrod  40  then compresses valve  53  to reduce the lumen size. A secondary mechanism may be adjusted for fine tuning at each interval. 
     While the specification describes the preferred designs, materials, methods of manufacture and methods of use, those skilled in the art will appreciate the scope and spirit of the invention with reference to the appended claims.