Patent Abstract:
An apparatus for modulating the pressure of a fluid such as a gas within the expandable portion of a guide wire catheter. A preferred embodiment apparatus features a means for controllably gripping and releasing the open, proximal end of a tubular guide wire, means for introducing a fluid to a desired pressure and volume into the expandable portion of the tubular guide wire through the open end, and, while maintaining the pressure and volume of fluid in the tubular guide wire, a means for introducing a sealing member into the open end of said tubular guide wire to seal the fluid in the tubular guide wire. In a particularly preferred embodiment, the apparatus also features a deflation tool for piercing the seal and letting the fluid out. Using this apparatus, the tubular guide wire can be re-sealed and re-opened as necessary.

Full Description:
BACKGROUND OF THE INVENTION  
       [0001]     The invention generally relates to interventional or surgical procedures, specifically relating to interventional cardiology and other intra-luminal procedures. The invention more particularly concerns a valve mechanism that allows modulation of pressure within a balloon or expandable member attached to, or otherwise located thereon, of a guide-wire or other catheter-like instrument.  
         [0002]     The use of a balloon attached to the end of a guide-wire is not new, see for example U.S. Pat. Nos. 6,251,084 (Coelho), and 4,790,813 (Kensey). In this arrangement, the guide-wire is actually a small diameter tube, with the lumen therethrough serving to allow fluid to be injected, and with the fluid being an agent used to expand the balloon.  
         [0003]     The balloon may serve various functions (e.g., locating and/or securing the wire or associated device within the artery, securing a wire within a catheter, or blocking the distal flow of fluid and/or debris created during one or more of the procedures).  
         [0004]     The balloon/guide-wire system may be used in various types of therapeutic and/or diagnostic procedures (e.g., percutaneous transluminal angioplasty, stent placement, the placement of ultrasonic or other diagnostic instruments, and the placement of thrombectomy devices, etc.). During the procedure several catheters or elongate instruments (together “catheters”) may be used sequentially, with the same guide-wire. Inserting instruments over, or alongside, a single guide-wire saves procedural time, since only one guide-wire would need to be placed. This approach may also improve safety, and reduce chance of infection, etc.  
         [0005]     Inserting a plurality of catheters, whether singularly or concurrently, requires the catheter(s) to be placed over the proximal end of the guide-wire. Where the guide-wire is arranged with a balloon at or near the distal end, the catheter(s) would need to be passed over any valve located at the proximal end of the guide-wire.  
         [0006]     Multiple catheters are commonly used when, for example, a physician performs an angiogram or other diagnostic procedure, and then decides to perform angioplasty or other therapeutic procedure or other interventional procedure. Most interventional procedures will require the placement of a guide wire for the subsequent delivery of the interventional instruments, and more recently some guide wires incorporate distal balloons to protect the distal tissues from debris generated during those same procedures. Since treatment and diagnostic procedures are becoming more commonplace, and the advancements in each of these technologies have led to procedures using even more catheters. These catheters are continually getting smaller, which allows the physician to reach tighter arteries and lumens within the body.  
         [0007]     For distal protection to be effective the balloon must remain inflated as catheters are exchanged over the guide wire. This necessitates a small diameter valve, which some refer to as a low-profile valve. Self-sealing valves have previously been disclosed; see for example U.S. Pat. Nos. 3,477,438 (Allen, et al.), 3,495,594 (Swanson), 3,837,381 (Arroyo), and 4,752,287 (Kurtz, et al.). These valves are commonly made from elastic (Allen, et al., and Kurtz, et al.) or resilient (Swanson) materials, and may require pressure in the system to operate (Arroyo). The properties of these valve materials, together with their operational pressures, require various of these valves to have large sealing areas. This does not facilitate the design of smaller catheters. Additionally, the valves would ideally operate over a wide range of pressures; including positive and negative pressures.  
         [0008]     Check valves have also been disclosed, see for example U.S. Pat. No. 4,653,539 (Bell), however these are directional valves, and therefore will not operate in both positive and negative pressure environments. Employing a vacuum in the system during navigation will facilitate the securing of the balloon to the guide-wire, that is, the balloon will stay folded or otherwise securely pressed against the side of the wire. This may allow the system to navigate tighter vessels or lumens. However, check valves, such as the one disclosed by Bell, do not meet this bi-directional operation need. Additionally, this type of valve, as well as the previously described self-sealing valves, require a syringe or special instrument to allow evacuation around the valve&#39;s sealing surface. These syringes or needles must be in-place during the entire evacuation procedure, or the valve will cease the fluid flow. This opens the systems up to situations where malfunctions or equipment breakage may yield an inserted and expanded balloon, which may not readily be collapsed. A system is needed that will allow evacuation without the application of vacuum or other specialized components.  
         [0009]     In addition to these stated concerns, the length of time required to complete the procedure is affected by these valves. This procedure time is of concern because of escalating medical costs, as well as the stress on the patient. These valves must allow rapid infusion and evacuation of balloon-filling fluids.  
         [0010]     Yet another low profile catheter valve, designed to fit small diameter catheters to navigate small pathways within the body such as blood vessels and ducts, is disclosed in U.S. Pat. No. 4,911,163 (Fina). A syringe is attached to the proximal end of an elongated tubular conduit (e.g. catheter) and used to inflate a distal balloon. Once the balloon is inflated, the catheter is clamped at the proximal end, the syringe is removed, and a plug is inserted into the lumen of the catheter, and then the clamp is removed. The plug is retracted and reinserted to adjust the balloon inflation volume as needed, using this same multi-step procedure. Needless to say, this type of valve is tedious to handle and the need for a separate clamping system further complicates the procedure and may potentially damage the catheter. Certainly the clamping pressures are very high, in order to totally collapse the circular catheter bore such that fluid will not leak (until the plug is inserted). Reinflating the balloon would also cause integrity problems if the catheter were reclamped at the same location.  
         [0011]     Another such low profile catheter valve is disclosed in U.S. Pat. No. 6,325,778 (Zadno-Azizi, et al.). This valve features a needle which is inserted coaxially with the guide-wire, wherein the needle is arranged to cover a fluid outlet port. The rate of balloon inflation and collapse is limited by the rate at which gas leaves the fluid outlet port. Since the fluid outlet port is radially outward from the guidewire&#39;s longitudinal axis, its size is geometrically constrained; that is, the larger diameter of the port, the less strength the guide-wire has. Since the guide-wire must withstand significant bending and torsional stress during the procedure, the port must be significantly less than the inside diameter of the guide-wire, thereby limiting the rate of evacuation of the balloon-filling fluid.  
         [0012]     This slow evacuation phenomenon may have been recognized by Coelho, as the disclosure prescribes a vacuum to collapse the balloon. Indeed, the tortuous path in the orifice of the Coelho device, through which the balloon inflation fluid is evacuated, must be nearly as small as the one disclosed by Zadno-Azizi. Here, the orifice must be considerably smaller than the inside diameter of the guide-wire, because the path of fluid escape is through a self-sealing valve; and the valve must have sufficient integrity to cause a seal against itself, after an evacuation needle is withdrawn.  
         [0013]     A valve which may utilize the overall inside diameter (or bore) of the guide wire is disclosed in U.S. Pat. No. 5,807,330 (Teitelbaum). The two basic concepts disclosed by Teitelbaum are a valve that is basically an insert with threads, wherein the threads secure the valve in the proximal end of the guide-wire; and an insert with a press-fit geometry, that is pressed into the proximal end of the guide-wire. Both of these concepts suffer similar shortcomings.  
         [0014]     The threaded insert requires extremely fine threads, which are expensive and tedious to manufacture even before considering the limited wall thickness of the guide-wire available for threading (perhaps only a few thousandths of an inch). Additionally, it is extremely difficult to align small threaded parts of this sort, which leads to misalignment and cross-threading. This problem would be especially prevalent where the same valve was actuated more than once during the same procedure—a common occurrence.  
         [0015]     The press-fit geometry requires parts of very tight tolerance, which are also tedious and expensive to produce. Press-fit components are normally manufactured for mechanical support, but press-fitting to cause a gas impermeable seal is possible; however, the insert would require an extremely uniform surface, which mates exactly with the inside surface at the proximal end of the guide-wire. It is this guide-wire surface which poses great manufacturing challenges.  
         [0016]     Boring or machining the inside surface of the guide-wire is very challenging because of the fine wall thickness—perhaps only a few thousandths of an inch. Machining of this component may produce irregular wall thinning, since no tube inside and outside is truly concentric, which could lead to premature failure.  
         [0017]     The aforementioned threaded and press-fit concepts disclosed by Teitelbaum both suffer manufacturing challenges as well as economic disadvantages. Finally, they have features that may lead to premature failure, necessitating removal of the device, following by re-insertion of a new balloon/guide-wire assembly.  
         [0018]     It is the intent of the embodiments of the present invention to overcome these and other shortcomings of the prior art.  
       SUMMARY OF THE INVENTION  
       [0019]     These and other objects of this invention are achieved by providing a valve mechanism for inflating and deflating a balloon or other expandable member on a guide-wire or catheter (e.g., at or near the distal end of a guide-wire), such that while the balloon is inflated, the proximal end of the wire would have a low profile and would not interfere with the use of other interventional devices using over-the-wire technique or rapid exchange systems. The system basically consists of detachable tools, one each for inflation and deflation of the balloon; additionally the inflation tool features in a preferred embodiment a gripping means, an inflating means, and a sealing means.  
         [0020]     The inflation tool serves the functions of gripping and releasing the guide wire proximal end; providing a means of modulating the pressure inside the guide wire resulting in balloon or expandable member inflation; and applying a deformable plug into the bore of the guide wire.  
         [0021]     In use, the proximal end of the guide wire is inserted into a chamber of the inflation tool; pressure is introduced via the inflation means thereby inflating the balloon or expandable member. The detachable inflation tool inserts a malleable plug in the proximal bore of the guide wire, thereby avoiding the need for costly machining and stringently tight tolerances of other devices, in order to maintain pressure within the guide wire upon the detaching the inflation tool. The sealing means prevents the escape of fluid (e.g., gas or liquid) from the guide wire for the duration of the procedure, or until release of pressure becomes necessary.  
         [0022]     The deflation tool serves the function of relieving the pressure in the balloon or expandable member of the guide wire, by piercing the sealing means in the proximal bore of the guide wire, and upon tool removal allows the fluid contained therein to escape. The valve mechanism herein described allows repeated inflation and deflation of the catheter or guide wire, by engaging the appropriate inflation or deflation tool. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0023]      FIG. 1  is a sectional view of one design of tool for applying the sealing plug.  
         [0024]      FIG. 2  is a perspective view of the sealing plug holding rod.  
         [0025]      FIG. 3  is a perspective view of the cam sleeve.  
         [0026]      FIG. 4  is a sectional view of the deflation needle tool prior to application.  
         [0027]      FIG. 5  is a sectional view of the deflation needle tool during application. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
     Description of Inflation Tool  
       [0028]     The preferred embodiment tool shown in  FIGS. 1, 2  and  3 , performs various functions, including but not limited to: 
        a) Gripping and releasing the guide wire proximal end;     b) Inflating the balloon on the distal end of the guide-wire, or placed somewhere therealong; and     c) Applying a sealing member in the proximal bore of the guide wire.        
 
         [0032]     These various device embodiments comprise sealing means, gripping means, and inflation means; while a separate device features deflation means. It is recognized that the device arranged for deflation may be attached to the device arranged for inflation (for convenience), although they may not share any componentry other than structural or housing. Additionally, it is contemplated by this invention that an inflation device or “inflation tool” may not necessarily comprise each of a gripping means, an inflation means, and a sealing means. As a non-limiting example, it is recognized that the inflation means may be a traditional syringe (where the inflation device was arranged to accept same). It is also recognized that the gripping means may be useful to perform other functions (e.g., gripping tubes at diagnostic and/or therapeutic equipment inlet ports, e.g., those found on bypass and dialysis machines.)  
         [0033]     Referring now to  FIGS. 1, 2 , and  3 , describing a preferred embodiment of the inflation tool, wherein like numbers indicate like components. A preferred gripping means is disclosed, wherein a tubular guide wire  12 , enters bore  37  in shaft  18  and passes through deformable member  19 , through pierceable diaphragm  20 , into cavity  21 , and stops against the face  23 A of rod  23 . Shaft  18  is slidably mounted in bore  41  of housing  28 , and, driven proximally (relative to the guide-wire  12 ) by spring  16 , thereby compressing deformable member  19  against the tapered bore  40  in housing  28 . Pierceable diaphragm  20  is an intact disc until pierced by the entering tubular guide wire  12 , the purpose of the diaphragm being to capture a charge of fluid (e.g., CO 2  or saline) in cavities  45 ,  21 , and channel  35 , prior to the piercing by the guide-wire  12 . Axial compression of the deformable member  19  results in the tubular guide wire  12  being gripped as the deformable member is moved radially inward by the taper  40 . An alternative to the pierceable diaphragm for retaining the charge of fluid in the cavity  21  and  45  is to ship the assembly with a smooth mandrel gripped in the deformable member  19  (not shown).  
         [0034]     In a preferred embodiment, the gripping means further features an insertion-release means, wherein the shaft  18  can be driven distally (relative to the guide-wire  12 ) by movement of lever  15  which, pivoting on pin  14 , moves the cone  13  attached to shaft  18 . Thus movement of the lever  15  radially inward relieves the pressure on the deformable member  19  and hence releases the guide wire  12  (the same feature may also be used in reverse, to assist the entry of the guide-wire into the device, as will be described later).  
         [0035]     In a preferred embodiment the inflation tool features a sealing means, with the sealing means arranged to deliver a sealing member material into the guide-wire to effect a seal, as will be described later. In this embodiment, the sealing means is preferentially located at the proximal end of the device, wherein there exists a mounted rod  23  which can move axially and rotationally in bore  21 A of housing  28 . Rod  23  is driven distally by spring  25  acting through flange  24  and is restrained by arm  26  coming in contact with one of the grooves  42  or  43 . An O-ring seal  29  seals rod  23  against bore  21 A. A sealing member material  22  is inserted in an off center bore in rod  23 . Surface  23 A of rod  23  is striated with grooves (not shown) to permit flow of fluid into the bore of tubular guide wire  12 .  
         [0036]     In a preferred embodiment the sealing member material is made from a plastically deformable or inelastic material, wherein such material may comprise organic and/or inorganic material. It is recognized that various materials may be suitable for this application, and the totality of material properties (e.g., strength, ductility, thixotropy, toughness, malleability, hysteresis, adhesiveness and fluid permeability, etc.) may reveal several good candidates.  
         [0037]     In a preferred embodiment the inflation tool features inflation means. At the lower portion of  FIG. 1  is shown a preferred embodiment of the inflation means, comprising an inflation syringe  44 , wherein the syringe contains a barrel  30  arranged to be attached to body  28  using adhesive or a threaded joint (not shown). The charge of fluid is pre-charged into cavities  45 ,  21  and  35 . A piston  31  attached to a plunger  32  drives fluid (gas or liquid) from chamber  45  via channel  35  into chamber  21  and thence into tubular guide wire  12 . Another preferred embodiment additionally features a latch  33  fastened to barrel  30 , wherein the latch  33  engages flange  34  after the plunger has been moved inward to deliver the fluid. The latch serves to prevent the piston and plunger from being driven back by the pressure trapped in cavity  21  (etc.) and balloon  11 .  
       Description of Inflation Tool Use  
       [0038]     A preferred embodiment inflation tool includes the gripping, inflation, and sealing means in combination, and allows the operator to hold the assembly  1  in one hand and with the thumb and fore-finger to squeeze the lever  15  toward the body  28  thus moving shaft  18  distally and relieving pressure on the deformable member  19 . The guide wire  12  is then inserted into shaft  18 , centralized by the tapered inlet  38 , passed through the deformable member  19 , to pierce the diaphragm  20  and come to rest against rod  23  at surface  23 A. Chamfers at  39  and  36  further aid in centralizing the guide wire. Surface  23 A of rod  23  is striated with fine grooves (not shown) to permit flow of fluid into the bore of tubular guide wire  12 . When the guide wire has bottomed on surface  23 A, the user releases the lever  15 , whereupon the shaft  18  is propelled to proximally and deformable member  19  is placed in compression. In turn this action, through taper  40 , causes the deformable member  19  to grip the guide wire  12  securely.  
         [0039]     In a preferred embodiment, the position of the guide wire may be confirmed visually by viewing the location via the lens  46  built in to a clear plastic housing  28 . Alternatively, if the housing is made from an opaque material the viewing lens  46  can be inserted in a tunnel as a separate component (not shown).  
         [0040]     In yet another embodiment, the correct position of the guide wire  12  can alternatively be ascertained by observing the location of a contrasting band of color  60 , formed on the guide wire  12 , relative to the entrance  61  of shaft  18 .  
         [0041]     Now returning to the preferred combination embodiment, the plunger  32  and attached piston  31  are then driven inward to propel the fluid in cavity  45  through channel  35  into cavity  21  and thence through the bore of guide wire  12  into the balloon  11 . In the case where gas is used to inflate the balloon, the plunger  32  may be driven to the bottom of the bore and allowed to return to a position controlled by flange  34  and latch  33 . This over-compression of the gas permits the initial pressure to be high to overcome the balloon resistance but drops the pressure as the balloon reaches full size, thus reducing the tendency to overpressure the vessel (not shown) in which the balloon is residing.  
         [0042]     With the balloon  11  inflated in the vessel, the arm  26  is rotated 180 degrees in this example (but any other angle would work with slots  42  &amp;  43  placed differently) so that rod  23  revolves to place the sealing material  22  to a position opposing the guide wire  12 . Then spring  25  urges rod  23  distally and drives the sealing material  22  into the open end of tubular guide wire  10  thus trapping the fluid in the guide wire and balloon. A plug  50  of sealing material  22 , is driven into the bore of the tubular guide wire  12 , as shown in  FIG. 4 .  
         [0043]     At this point the lever  15  is again pressed inward radially and the guide wire is removed from the device, and the wire is ready for the rest of the interventional procedure, which might involve the passage of angioplasty balloons, stent balloons, diagnostic ultrasound, or other procedure requiring a balloon protected or anchored guide wire with the balloon inflated.  
       Description of Deflation Tool  
       [0044]     Referring to  FIGS. 4 and 5 , a preferred embodiment of the deflation tool  56  is basically constructed from four elements, a handle  51 , a tube  54 , a spring  52 , and a needle  53 . The handle has a bore  57  of about 0.016 inch diameter, a little larger than the outside diameter of the guide wire  12  which is typically 0.015 inch, and has a lead in taper  55  to allow the operator to easily locate the bore  57 .  
         [0045]     The proximal end (relative to the user&#39;s hand while utilizing the tool) of the needle  53  is held centrally in the bore  57  by tube  54 . Tube  54 , together with the needle  53 , and the handle  51  can be assembled together by any convenient means, including but not limited to welding, using an adhesive, or a crimping operation. The needle is approximately 0.005 inch in diameter in this embodiment, and is supported by the spring coils  52  to prevent the needle from being bent during use and to align the distal end (relative to the user&#39;s hand while utilizing tool) of the needle on the centerline of the bore  57 . The length of the plug  50  of sealing member material  22  (see  FIG. 1 ) in the proximal end of the guide wire  12  is preferably about 0.030 inch long axially, although other dimensions may be more suitable depending on the composition of the sealing material and the pressure at which the balloon requires. The guide wire outside diameter  59  is typically 0.015 inch and the bore  58  can typically range from 0.011 inch to 0.005 inch. The needle needs to be sufficiently large to provide a bore through the plug  50  that it will allow the balloon to be deflated rapidly, but not so large that the plug  50  is smeared along the bore  58  too far to require a very long needle. It has been found that a 0.005 inch diameter needle permits deflation times that are acceptable (less than 30 seconds), utilizing a 0.007 inch diameter guide wire bore. Clearly these dimensions are examples only and could be adjusted to accommodate guide wires or catheters of different diameters.  
         [0046]     The deflation tool embodiment described can be used multiple times, but it is unlikely that the operator will ever need to inflate and deflate the balloon more than 5 times in a procedure. The needle  53  is therefore preferably required to penetrate several times the length of the plug  50  into the guide wire bore  58  for this to be achieved.  
       Description of Deflation Tool Use  
       [0047]     The operator inserts the proximal end of the guide wire  12  into the lead taper  55  of the deflation tool  56  compressing the spring  52  to the fully compressed condition. The plug  50  is pierced as shown in  FIG. 5 , and smears into an elongated tubular shape  62  concentric to the bore  57 . The balloon  11  (see  FIG. 1 ) then deflates due to its inherent elastic recovery, and/or vacuum can be applied to the tubular guide wire  12  by syringe or other means (neither shown) to accelerate the deflation time. The tool is then removed and is available for any subsequent use.  
         [0048]     Thus since the invention disclosed herein may be embodied in other specific forms without departing from the spirit or general characteristics thereof, some of which forms have been indicated, the embodiments described herein are to be considered in all respects illustrative and not restrictive, by applying current or future knowledge. The scope of the invention is to be indicated by the appended claims, rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Technology Classification (CPC): 0