Abstract:
A catheter and a guidewire exchange system includes a catheter and a guide member. The catheter includes a lumen extending through the shaft and sized to receive the guidewire, and a longitudinal guideway enabling transverse access from the shaft exterior surface to the lumen. The guide member includes a housing, a catheter passageway extending through the housing and adapted to slidably receive the catheter, a guidewire passageway extending from one end of the housing into the catheter passageway and including a tube adapted to merge the guidewire transversely through the guideway and into the first lumen, and a user-activated device positioned in the guidewire passageway and including a clamping body adapted to clamp the guidewire and thereby secure the guidewire in the guidewire passageway.

Description:
TECHNICAL FIELD  
       [0001]     The present invention generally relates to medical catheters and medical apparatuses involving medical catheters. The present invention more particularly relates to seals for guide members of Multi-Exchange catheters.  
       BACKGROUND  
       [0002]     Cardiovascular disease, including atherosclerosis, is a leading cause of death in the U.S. The medical community has developed a number of methods and devices for treating coronary heart disease, some of which are specifically designed to treat the complications resulting from atherosclerosis and other forms of coronary arterial narrowing.  
         [0003]     One method for treating atherosclerosis and other forms of coronary narrowing is percutaneous transluminal coronary angioplasty, commonly referred to as “angioplasty” or “PTCA.” The objective in angioplasty is to enlarge the lumen of the affected coronary artery by radial hydraulic expansion. The procedure is accomplished by inflating a balloon of a balloon catheter within the narrowed lumen of coronary artery.  
         [0004]     In addition to PTCA, catheters are used for delivery of stents or grafts, therapeutic drugs (such as anti-vaso-occlusion agents or tumor treatment drugs) and radiopaque agents for radiographic viewing. Other uses for such catheters are well known in the art.  
         [0005]     The anatomy of coronary arteries varies widely from patient to patient. Often a patient&#39;s coronary arteries are irregularly shaped, highly tortuous and very narrow. The tortuous configuration of the arteries may present difficulties to the physician in proper placement of a guidewire, and advancement of a catheter to a treatment site. A highly tortuous coronary anatomy typically will present considerable resistance to advancement of the catheter over the guidewire.  
         [0006]     Therefore, it is important for a catheter to be highly flexible. However, it is also important for a catheter shaft to be stiff enough to push the catheter into the vessel in a controlled manner from a position far away from the distalmost point of the catheter.  
         [0007]     Catheters for PTCA and other procedures may include a proximal shaft, a transition section and a distal shaft having a flexible distal tip. In particular, the catheters have a proximal shaft, which is generally rigid for increased pushability and a more flexible distal shaft with a flexible distal tip for curving around particularly tortuous vessels. The proximal shaft may be made stiff by the insertion of a thin biocompatible tube, such as a stainless steel hypotube, into a lumen formed within the proximal shaft. The transition section is the portion of the catheter between the stiffer proximal shaft and the more flexible distal shaft, which provides a transition in flexibility between the two portions.  
         [0008]     With some types of catheter construction, when an increase in resistance occurs during a procedure there is a tendency for portions of the catheter to collapse, buckle axially or kink, particularly in an area where flexibility of the catheter shaft shifts dramatically. Consequently, the transition section is often an area where the flexibility of the catheter gradually transitions between the stiff proximal shaft and the flexible distal shaft. It is known in the art to create a more gradual flexibility transition by spiral cutting a distal end of the hypotubing used to create stiffness in the proximal shaft. Typically, the spiral cut is longitudinally spaced father apart at the hypotube proximal end creating an area of flexibility, and longitudinally spaced closer together at the hypotube distal end creating an area of even greater flexibility.  
         [0009]     In a typical PTCA procedure, it may be necessary to perform multiple dilatations, for example, using various sized balloons. In order to accomplish the multiple dilatations, the original catheter must be removed and a second catheter tracked to the treatment site. When catheter exchange is desired, it is advantageous to leave the guidewire in place while the first catheter is removed to properly track the second catheter.  
         [0010]     Two types of catheters commonly used in angioplasty procedures are referred to as over-the-wire (OTW) catheters and rapid exchange (RX) catheters. A third type of catheter with preferred features of both OTW and RX catheters, which is sold under the trademarks MULTI-EXCHANGE, ZIPPER MX, ZIPPER, MX and/or MXII, is discussed below. An OTW catheter&#39;s guidewire lumen runs the entire length of the catheter and may be positioned next to, or enveloped within, an inflation shaft. Thus, the entire length of an OTW catheter is tracked over a guidewire during a PTCA procedure. A RX catheter, on the other hand, has a guidewire lumen that extends within only the distalmost portion of the catheter. Thus, during a PTCA procedure only the distalmost portion of a RX catheter is tracked over a guidewire.  
         [0011]     If a catheter exchange is required while using a standard OTW catheter, the user must add an extension wire onto the proximal end of the guidewire to maintain control of the guidewire, slide the catheter off of the extended guidewire, slide the new catheter onto the guidewire and track back into position. Multiple operators are required to hold the extended guidewire in place while the original catheter is exchanged in order to maintain its sterility.  
         [0012]     A RX catheter avoids the need for multiple operators when exchanging the catheter. With a rapid exchange catheter, the guidewire runs along the exterior of the catheter for all but the distalmost portion of the catheter. As such, the guidewire can be held in place without an extension when the catheter is removed from the body. However, one problem associated with RX catheters is the guidewire, and most of the catheter, must be removed from the body in order to exchange guidewires. Essentially the procedure must then start anew because both the guidewire and the catheter must be retracked to the treatment site. An OTW catheter, with the guidewire lumen extending the entire length of the catheter, allows for simple guidewire exchange.  
         [0013]     A balloon catheter capable of both fast and simple guidewire and catheter exchange is particularly advantageous. A catheter designed to address this need is sold by Medtronic Vascular, Inc. of Santa Rosa, Calif. under the trademarks MULTI-EXCHANGE, ZIPPER MX, ZIPPER, MX and/or MXII (hereinafter referred to as the “MX catheter”). An MX catheter is disclosed in U.S. Pat. No. 4,988,356 to Crittenden et al.; co-pending U.S. patent application Ser. No. 10/116,234, filed Apr. 4, 2002; co-pending U.S. patent application Ser. No. 10/251,578, filed Sep. 18, 2002; co-pending U.S. patent application Ser. No. 10/251,477, filed Sep. 20, 2002; co-pending U.S. patent application Ser. No. 10/722,191, filed Nov. 24, 2003; and co-pending U.S. patent application Ser. No. 10/720,535, filed Nov. 24, 2003, all of which are incorporated by reference in their entirety herein.  
         [0014]     The MX catheter includes a catheter shaft having a guidewire lumen positioned side-by-side with an inflation lumen. The MX catheter also includes a longitudinal cut that extends along the catheter shaft and that extends radially from the guidewire lumen to an exterior surface of a catheter shaft. A guide member through which the shaft is slidably coupled cooperates with the longitudinal cut such that a guidewire may extend transversely into or out of the guidewire lumen at any location along the longitudinal cut&#39;s length. By moving the shaft with respect to the guide member, the effective over-the-wire length of the MX catheter is adjustable.  
         [0015]     The guidewire is threaded into a guidewire lumen opening at the distal end of the catheter and out through the guide member. The guidewire lumen envelopes the guidewire as the catheter is advanced into the patient&#39;s vasculature while the guide member and guidewire are held stationary. Furthermore, the indwelling catheter may be removed by withdrawing the catheter from the patient while holding the proximal end of the guidewire and the guide member in a fixed position. When the catheter has been withdrawn to the point where the distal end of the cut has reached the guide member, the distal portion of the catheter over the guidewire is of a sufficiently short length that the catheter may be drawn over the proximal end of the guidewire without releasing control of the guidewire or disturbing its position within the patient.  
         [0016]     During some catheter advancing and retracting processes, including a catheter exchange, it can be difficult to hold the guidewire proximal end and the guide tool in a fixed position with one hand, while retracting or advancing the catheter with the other hand. Once the guidewire is positioned in a desired region of the patient&#39;s body, it is important to maintain that guidewire position to enable the present catheter or a replacement catheter to quickly advance through an occluded or tortuous vein.  
         [0017]     While the MX catheter provides many advantages over RX catheters, like an RX catheter, the proximal shaft may not be completely secured in the hemostasis valve. For example, in a typical dye injection the physician may pull a slight negative pressure to ensure that no air bubbles are in the system. However, if the physician pulls a very heavy vacuum, there remains the possibility that air may enter the patient through the hemostasis valve if it is not sealed sufficiently. Similarly, RX catheters used with passive/active gaskets in a hemostasis valve may also be susceptible to air entering if the gasket is not closed properly and a very heavy vacuum is drawn.  
         [0018]     Accordingly, it is desirable to provide an apparatus that can reduce or eliminate the opportunity for unwanted air aspiration. In addition, it is desirable to provide such an apparatus that does not slow down guidewire insertion or other medical processes involving the catheter. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.  
       BRIEF SUMMARY  
       [0019]     A system is provided to exchange a catheter and/or a guidewire. The system includes a catheter and a guide member. The catheter includes a lumen extending through the shaft and sized to receive the guidewire, and a longitudinal guideway enabling transverse access from the shaft exterior surface to the lumen. The guide member includes a housing, a catheter passageway extending through the housing and adapted to slidably receive the catheter, a guidewire passageway extending from one end of the housing into the catheter passageway and including a tube adapted to merge the guidewire transversely through the guideway and into the first lumen, and a user-activated device positioned in the guidewire passageway and including a clamping body adapted to clamp the guidewire and thereby secure the guidewire in the guidewire passageway. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]     The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and  
         [0021]      FIG. 1  is a perspective view of a guide member with a guide wire extending through a guide member and into a catheter according to the present invention;  
         [0022]     FIGS.  2 A-D are cross sectional views of a catheter at points A-A, B-B, C-C, and D-D illustrated in  FIG. 1 ;  
         [0023]      FIG. 3  is a perspective cross sectional view of an oval proximal shaft;  
         [0024]      FIG. 4  is a cross sectional view of a circular proximal shaft;  
         [0025]      FIG. 5  is a sectional view of a guide member and its components according to the present invention;  
         [0026]      FIG. 6  is a sectional view of the proximal guidewire pathway including the guidewire port and the tube, along with a tapered seal secured in the guidewire port according to an embodiment of the present invention;  
         [0027]      FIG. 7  is a sectional view of the proximal guidewire pathway including the guidewire port and the tube, along with a compression seal secured in the guidewire port according to an embodiment of the invention;  
         [0028]      FIG. 8  is a perspective view of a flap seal according to an embodiment of the invention; and  
         [0029]      FIG. 9  is a sectional view of the proximal guidewire pathway including the guidewire port and the tube, along with the flap seal secured in the guidewire port and a switch extending through an opening in the guide member according to an embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0030]     The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description.  
         [0031]     The present invention is used with an MX catheter, an exemplary embodiment of which is illustrated in  FIG. 1 . The catheter  12  includes an elongate, flexible, cylindrical main body having a distal shaft  20  and a proximal shaft  22 . According to the present embodiment, the catheter  12  is a delivery catheter for such procedures as PTCA or stent delivery and has a balloon  24  mounted around the catheter body near the catheter distal end  18 . The balloon  24  may be inflated and deflated through the catheter inflation lumen  26 . The inflation lumen  26  communicates with a fitting  28  at the catheter proximal end, and extends the catheter length to terminate in communication with the balloon interior at the catheter distal end  18 . The catheter  12  also includes a guidewire lumen  30  that receives the guidewire  14  and extends the entire catheter length. A longitudinal cut extends into the guidewire lumen  30  along the length of most of the proximal shaft  22  to form a guideway  32 . The proximal shaft distal section  34  does not include the guideway  32 . The guidewire lumen  30  and the inflation lumen  26  are coaxially arranged in the distal shaft  20  according to the present embodiment.  
         [0032]     The present invention includes a guide member for the MX catheter  12 .  FIG. 1  depicts a guide member  10  according to an embodiment of the invention, with a guide wire  14  extending through the guide member  10  and into the MX catheter  12 .  FIGS. 2A  to  2 D are cross sections of the catheter  12  at points A-A, B-B, C-C, and D-D along the catheter length. The guide member  10  serves as a juncture in which the catheter  12  and guidewire  14  may be merged or separated so that the guidewire portion that extends proximal to the guide member  10  is separated from the catheter  12 , and the guidewire portion that is located distal to the guide member  10  is contained and housed within the catheter, although the guidewire distal end  16  may protrude out of the catheter distal end  18 .  
         [0033]     The catheter proximal shaft  22  described above can be modified to suit various needs. For example, the proximal shaft can be a tri-lumen shaft to provide passage for various drugs, fluids, wires, or other necessary compositions or equipment. Further, the proximal shaft may be oval, circular, or other suitable shape.  FIG. 3  is a perspective cross sectional view of an oval proximal shaft  22  according to one embodiment of the invention, and  FIG. 4  is a cross sectional view of a circular proximal shaft  48  according to another embodiment of the invention. Each of the proximal shafts  22 ,  48  has a respective guidewire lumen  30 ,  52  that is accessible through a guideway  32 ,  54  located along the proximal shaft length. Each of the proximal shafts  22 ,  48  also includes an inflation lumen  26 ,  62  that extends side by side with the guidewire lumen  30 ,  52  along the proximal shaft length. The inflation lumens  26 ,  62  are preferably supported by a stiffening member  60 ,  64  such as a hypotube. The inflation lumen  62  in the embodiment depicted in  FIG. 4  is crescent shaped and the hypotube stiffening member  64  also is formed in the same shape to withstand force transmission along the catheter length. The stiffening members may further include a transition section at their respective distal sections in conjunction with a transition between the relatively stiff proximal shaft to the relatively flexible distal shaft and avoid shaft kinking at the junction therebetween. For example, the hypotube  60  may be skived at its distal end, with the skived portion extending into the distal section as depicted in  FIG. 2C .  
         [0034]     Returning to  FIG. 1 , the proximal shaft  22  can be formed from suitable biomedical grade materials such as polyethylene, cross-linked polyethylene, polyolefins, polyamides, blends of polyamides and polyolefins, fluoropolymers, polyesters, polyketones, polyimides, polysulphones, polyoxymethylenes, and compatibilizers based on polyolefins, including grafted polyolefins, and other comparable materials. A lubrication additive may also be used with any polymer and may include polyethylene micro-powders, fluoropolymers, silicone based oils, fluoro-ether oils, molybdenum disulphide and polyethylene oxide. Additionally, a reinforcing additive may be used such as nano-clays, graphite, carbon fibers, glass fibers, and polymeric fibers. The distal shaft  20  can be made of a suitable polyethylene or polyolefin that readily bonds to the proximal shaft  22 .  
         [0035]     Turning now to  FIG. 5 , the guide member  10  and its components will be discussed according to one embodiment of the invention. The guide member  10  surrounds the proximal shaft  22  and includes proximal and distal ends  92 ,  94 . An outer tubular member  96  freely rotates around an inner main body  98  and hence is decoupled from the inner main body  98 . An inwardly extending distal annular wall  70  prevents the main body  98  from slipping out of the outer member  96 . A retaining clip  71  includes a tab  72  that extends into a space  73  formed by two main body walls  74 ,  75 . Additional tabs may be used as necessary to retain the inner main body  98  within the tubular member  96 .  
         [0036]     The guide member main body  98  includes a catheter passageway  88  extending longitudinally in a generally straight line from the guide member proximal end  92  to the guide member distal end  94 . A guidewire passageway  80  extends distally from the guide member proximal end  92  through an entrance port  82  into a tube  86  and then into the catheter guidewire lumen  30 , although the catheter is not depicted in  FIG. 5 . The passageway  80  is configured to slidingly receive the proximal shaft  22 , and has a cross sectional shape that approximates the proximal shaft shape, whether the proximal shaft is circular, oval, triangular, shamrock shaped, or otherwise shaped. The passageway  80  enlarges in a central area to provide space for a keel  84  that is aligned with the passageway  80  and positioned to spread the catheter guideway  32  and extend into the catheter guidewire lumen  30  to enable guidewire insertion during use.  
         [0037]     The entrance port  82  is configured to mate with a conventional wire introducer tool and is tapered to aid in loading such a tool. The tube  86  may vary in its length, although in an exemplary embodiment of the invention the tube  86  extends through the catheter guidewire lumen  30  approximately thirty-five millimeters past the guide member distal end  94 . The tube  86  may be formed from a flexible material such as a polyimide, and particularly the tube region that extends through the catheter guidewire lumen  30 . In one embodiment of the invention the tube region that introduces the guidewire  14  into the guidewire lumen  30  may be substantially rigid to provide the necessary support for the guidewire  14 .  
         [0038]     The guide member  10  is made of blends of polyamides and polyolefins in an exemplary embodiment of the invention. Other exemplary materials include ceramics, metals such as stainless steel, and other polymers such as polyamides and liquid crystal polymers. Lubrication additives such as polyethylene micro-powders, fluoropolymers, silicone-based oils, fluoro-ether oils, molybdenum disulphide, and polyethylene oxide may be included. Reinforcing additives such as nano-clays, graphite, carbon fibers, glass fibers, polyesters, polyketones, polyimides, polysulphones, polyoxymethylenes, polyolefins, cross-linked polyolefins may also be included, along with compatibilizers based on polyolefins, such as grafted polyolefins, ceramics, and metals.  
         [0039]     An exemplary guide member operation will now be described, although the procedures in the following description clearly set forth only one of many operations enabled by the guide member  10 . After the guidewire  14  and a guide catheter (not shown) are inserted into a patient, the catheter  12  is inserted with a backloading operation. The guidewire  14  is inserted into the catheter distal end  18  and threaded proximally through the guidewire lumen  30  until the guidewire tube  86  captures the guidewire proximal end and directs it into the passageway  80  and then out of the guide member proximal end  92 . This procedure can be accomplished with the guide member  10  adjacent the catheter guideway distal end. As the distal shaft  20  enters the patient, the guide member  10  will reach the hemostatic valve (not shown). The guide member  10  is not intended to enter the valve and is seated adjacent to the valve. The proximal shaft  22  is then advanced through the guide member, and the keel  84  engages the catheter guideway  32 . After the catheter  12  is inserted, the hemostatic valve may be closed down on the catheter shaft at a region that is distal to the guide member  10 . Since the tube  86  extends in to the distal shaft  20 , it is subjected to the valve clamping force. If a wire change is required, one simply withdraws the guidewire  14  from the guide member  10  as the guide member  10  is seated against the valve and as the proximal shaft  22  remains in the patient. A new guidewire is then inserted into the catheter through the passageway  80 . If a catheter exchange is required, one simply holds the guidewire  14  in place and begins moving the proximal shaft  22  proximally through the guide member. Another catheter may then be backloaded onto the guidewire  14  and introduced into the patient as described above.  
         [0040]     In order to overcome the potential for air aspiration through the guidewire lumen  30  at the catheter proximal end, the passageway  80  is adapted to include a seal that prevents or minimizes air movement through the passageway.  FIG. 6  is a sectional view of the proximal guidewire pathway  80  including the guidewire port  82  and the tube  86 , along with a tapered seal  40  secured in the guidewire port  82 . The seal  40  has an opening  46  extending therethrough that is sized to be slightly wider than the guidewire diameter in order to enable substantially frictionless guidewire advancement and retraction. The opening  46  is also narrow enough to substantially eliminate airflow through the opening  46  during guidewire advancement.  
         [0041]     The seal  40  includes a rigid cylindrical body  42  that secures the seal  40  in the guidewire entrance port  82 . The cylindrical body  42  includes a threaded outer surface  43  that rotatably engages with threads  81  in the guidewire entrance port  82 . The seal  40  also includes a tapered tip  44  that is formed from an elastomer material. The tip  44  has an outer surface in the form of a truncated cone. When the seal  40  is rotated in a tightening direction, the seal can be secured in the guidewire entrance port  82  until the tip  44  abuts a tapered tube entrance  83  as illustrated in  FIG. 6 . When the tip  44  is merely abutting the tube entrance  83 , the opening  46  is wide enough to enable substantially frictionless guidewire advancement and retraction and to substantially eliminate airflow through the opening  46 .  
         [0042]     If a user wishes to completely eliminate airflow through the opening  46  or to clamp the guidewire in a desired position, the seal  40  can be further rotated in a tightening direction. Further tightening causes the elastomer material in the tip  44  to change shape and constrict the opening  46  around the guidewire  14 . The seal  40  can be rotated until the guidewire  14  is tightly secured in its position, and a substantially airtight seal is provided around the guidewire  14 . Likewise, if a user wishes to unclamp the guidewire, the seal  40  can be rotated in a loosening direction until the elastomer material in the tip  44  retains its original shape and the opening  46  retains its original diameter.  
         [0043]      FIG. 7  is a sectional view of the proximal guidewire pathway  80  including the guidewire port  82  and the tube  86 , along with a compression seal  50  secured in the guidewire port  82  according to another embodiment of the invention. The compression seal  50  has an opening  56  extending therethrough that is sized to be slightly wider than the guidewire diameter in order to enable substantially frictionless guidewire advancement and retraction. The opening  56  is also narrow enough to substantially eliminate airflow through the opening  56  during guidewire advancement.  
         [0044]     The seal  50  is depicted in  FIG. 7  to have a proximal cylindrical portion and a distal tapered region to illustrate that the seal  50  can be formed to closely match the entrance port contours. However, the compression seal  50  can be formed to have an entirely cylindrical shape if the seal rests against a lateral wall. Further, the compression seal can be formed to rest against any entrance port surface or other surface that provides a counter force that directly opposes a seal tightening force. The main difference between the compression seal  50  and the tapered seal  40  is the compression seal is shaped to have the seal  50  primarily compressed in a longitudinal direction when subjected to a tightening force, and expanded in a lateral direction as an effect of the longitudinal compression. The lateral compression causes the opening  56  to constrict and form a substantially airtight seal around the guidewire and also clamp the guidewire in place. In contrast, the tapered seal  40  is shaped to be compressed primarily in a lateral direction.  
         [0045]     As with the tapered seal  40 , the compression seal  50  is formed from an elastomer material that changes shape when compressed to constrict the guidewire opening  56 , and retains its original shape when the compression force is removed. A tightening tool  52  includes a threaded rigid cylindrical body that secures the seal  50  in the guidewire entrance port  82 . The cylindrical body  52  includes a threaded outer surface  53  that rotatably engages with threads  81  in the guidewire entrance port  82 . When the tool  52  is rotated in a tightening direction, the tool  52  compresses the seal  50  in a primarily longitudinal direction. The longitudinal compression causes the seal to expand in a lateral direction. The lateral expansion causes the guidewire opening  56  to constrict, forming a substantially airtight seal with the guidewire  14  and securing the guidewire  14  in place. When the tool  52  is rotated in a loosening direction, the seal  50  retains its original shape.  
         [0046]     Referring now to  FIG. 8 , a perspective view of a flap seal  60  according to another embodiment of the invention reveals a two part structure. The first part is a threaded rigid cylindrical body  62  similar to the threaded structures  42 ,  52  described above. The threaded body  62  engages with threads  81  in the guidewire entrance port  82  to secure the seal  60  in place. The threaded body  62  includes an opening (not shown) through which the guidewire  14  extends. The second part of the seal  60  is a tapered body  64  that is essentially formed in the shape of a cone with a truncated tip that defines an opening  68  that is continuous with the opening (not shown) in the threaded body  62 . A plurality of longitudinal slits  66  are formed in the tapered body  64 . The slits  66  separate the distal tapered body  64  into a plurality of flaps  67 . The flaps are formed from an elastomer or other flexible material, and are biased in a position such that they do not touch one another. Although only two flaps  67  are depicted in  FIG. 8 , additional slits may be included to separate the tapered body  64  into additional flaps.  
         [0047]     During guidewire advancement and retraction, the flaps  67  are spread apart enough to allow a substantially frictionless guidewire pathway. The flaps  67  are biased in a separated position, but still substantially limit or prevent airflow into the guidewire passageway  80  during guidewire advancement. The guidewire can be secured in place by rotating the threaded body  62  in a tightening direction, causing the flaps  67  to contact the tube entrance  83  and be pressed around the guidewire  14 . In the tightened position, the flaps  67  secure the guidewire in place and also further provide an airflow seal. The flaps  67  return to their biased separated position when the threaded body  62  is rotated in a loosening direction.  
         [0048]     The above descriptions of various seals include the use of a rotatable cylindrical body that is threadedly engaged with the guidewire entrance port  82  to provide a user with ease and efficiency in the process of clamping or freeing the guidewire and limiting airflow through the opening  46 . However, it is within the purview of the invention that the seal  40  and any of the other seals described herein can be secured and manipulated by a user using any suitable conventional clamp or securing device or material.  FIG. 9  is a sectional view of the proximal guidewire pathway  80  including the guidewire port  82  and the tube  86 , along with the flap seal  60  secured in the guidewire port  82 , although any of the seals discussed above may be used in accordance with the embodiment illustrated in  FIG. 9 . Instead of rotating the seal  60  to clamp the guidewire and form a seal, an actuating switch or button  77  is coupled to the guide member  10  and is secured in a through hole  88  using tabs  87  and springs  99  to perform the clamping function.  
         [0049]     The seal  60  is secured in the guidewire port  82  using the threaded body  62  or any suitable securing mechanism. With the seal  60  in place, the actuating button  77  is configured to be pressed to a locking position such that a first end  79  of the button presses one of the flaps  67   a  toward an opposing flap  67   b  to clamp the guidewire  14  and provide a substantially airtight seal with the guidewire  14 . The button  77  can be equipped with a hook  78  or other structure to latch the button  77  in the locking position in an exemplary embodiment of the invention. The hook  78  can engage with a tab  89  or any other structure that is integral with or otherwise combined with the guide member  10 . To release the button  77  from the locking position, the user need only press the button  77  again and allow the hook to disengage with the tab.  
         [0050]     In an embodiment similar to that depicted in  FIG. 9 , the flap  67   a  is formed using an elastomer or another flexible material, and the flap  67   b  is a rigid material. Alternatively, the flap  67   b  can extend into the tube  86 , and the button  77  can be positioned above the tube  86  and the flap  67   b  so that the tube  86  and the flap  67   b  together clamp the guidewire  14  and provide a substantially airtight seal with the guidewire  14  when the button  77  is in the locking position. Further, the advantages provided by the embodiment illustrated in  FIG. 9  can be accomplished using any of the other seals described herein and equivalent seals together with the actuating button  77 .  
         [0051]     While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as set forth in the appended claims and the legal equivalents thereof.