Abstract:
A balloon catheter assembly including an inflation port having a seal disposed thereon to maintain the inflation lumen and balloon substantially free of air or other gas prior to use or during storage. Prior to use, the evacuated lumen is filled with liquid which releases the vacuum therein and brings the pressure up to at least atmospheric pressure without introducing air or other gases into the lumen, assuring a properly prepared balloon catheter free of air. A sealing device is provided which allows placing a seal on the port while pulling or maintaining vacuum on the lumen.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention generally relates to intravascular catheters, particularly balloon catheters. More precisely, the present invention relates to balloon catheters with a vacuum sealed inflation lumen.  
         BACKGROUND OF THE INVENTION  
         [0002]    The use of intravascular catheters has become an effective method for treating many types of vascular disease. In general, an intravascular catheter is inserted into the vascular system of the patient and navigated through the vasculature to a desired target site. Using this method, virtually any target site in the patient&#39;s vascular system may be accessed, including the coronary, cerebral, and peripheral vasculature. Examples of therapeutic purposes for intravascular catheters include percutaneous transluminal angioplasty (PTA) and percutaneous transluminal coronary angioplasty (PTCA).  
           [0003]    Intravascular catheters are commonly used in conjunction with a guidewire. A guidewire may be advanced through the patient&#39;s vasculature until it has reached a target location. Once in place, a catheter may be threaded onto the guidewire and urged distally until the distal end of the catheter reaches a target location.  
           [0004]    Intravascular catheters adapted for use with a guidewire typically are classified as over-the-wire (OTW) or single-operator-exchange (SOE). An OTW catheter includes a guidewire lumen extending from the distal tip of the catheter to the proximal end of the catheter. When intravascular catheters are used, it is common for physicians to remove one catheter and exchange it for another. While exchanging catheters, the guidewire should preferably be held in place so as to keep its distal end near the target area. A portion of the guidewire is typically grasped by the physician in order to withdraw the first catheter while maintaining the distal end of the guidewire in the desired position. To properly anchor the guidewire, a portion of the guidewire should preferably be exposed at all times so it is available for the physician to grasp. In the case of an OTW catheter, the length of the guidewire extending beyond the patient&#39;s body should be longer than the catheter. Consequently, in many cases, intravascular guidewires are longer than 200 cm or require guidewire extensions to facilitate exchange, and there may be more than 200 cm of wire extending from the patient. Managing this length of wire during a catheter exchange procedure can be awkward, and often requires more than one person.  
           [0005]    SOE catheters overcome some of the difficulties encountered when exchanging OTW catheters. Accordingly, SOE catheters have a relatively short guidewire lumen relative to the length of the catheter. Therefore, the length of guidewire extending beyond the body of the patient need only be slightly longer than the guidewire lumen of the catheter. The physician may anchor or hold the guidewire as the first catheter is removed from the body, with the exchange occurring over the shorter guidewire lumen. The guidewire lumen of an SOE catheter typically includes a distal guidewire port disposed at the distal tip of the catheter and a proximal guidewire port disposed proximally of the distal end of the catheter.  
           [0006]    When in use, intravascular catheters enter a patient&#39;s vasculature at a convenient location and then are urged to a target region. Once the distal portion of the catheter has entered the patient&#39;s vascular system, the physician may urge the distal tip forward by applying longitudinal forces to the proximal portion of the catheter. Then a physician may use the functional portion of the catheter to perform a medical procedure. For example, a physician may inflate an angioplasty balloon by passing a fluid through an inflation lumen.  
           [0007]    Before a medical procedure can be performed, the catheter will need to be prepared. For example, an angioplasty balloon should be free of air before using an angioplasty catheter. The procedure for evacuating air from the balloon typically includes passing fluid through the inflation lumen into the balloon and then eliminating any air bubbles that may be present. To remove the air bubbles, a person might need to tap or bump the catheter to urge the bubbles out of the balloon. Not only can this procedure be time consuming, it can lead to kinks in a catheter shaft or cracked manifolds. For these reasons, a need exists for catheters that can reduce the amount of preparation time and reduce potential damage to the catheter during preparation.  
           [0008]    Further, if the procedure is not conducted properly, there is no real assurance that the balloon is completely evacuated of air. This is an obvious problem if a balloon were to rupture in the vasculature. Further, this can be an important issue when precise balloon inflation is required. For example, air bubbles in an angioplasty balloon may alter the size or shape of the balloon once it is inflated. If the balloon is to be used in a sensitive tissue area, e.g., the central nervous system, alterations of the balloon can have major consequences. A need therefore exists for a catheter with increased assurance that the balloon is evacuated of air.  
         SUMMARY OF THE INVENTION  
         [0009]    The present invention generally relates to intravascular catheters, particularly balloon catheters. More precisely, the present invention relates to balloon catheters with a vacuum sealed inflation lumen. According to a preferred embodiment, the present invention comprises a catheter with substantially reduced preparation time and reduced potential damage to the catheter during preparation. Preferably, the catheter further comprises increased assurance that the balloon is evacuated of air or other gas.  
           [0010]    According to a preferred embodiment, the present invention comprises a seal for the proximal entry port of an inflation lumen on a balloon catheter such as an over-the-wire catheter. In a preferred embodiment, an over-the-wire (OTW) catheter comprises an elongate member having a proximal end and a distal end. Preferably, a balloon is attached proximate the distal end.  
           [0011]    In a preferred embodiment, the catheter further comprises a first tube including a proximal end, a distal end, and a first lumen extending therethrough. Preferably, the first tube defines the outside surface of the elongate member, or alternatively, the first tube can be disposed within the elongate member. In an exemplary embodiment, the first lumen is an inflation lumen for a balloon, such as an angioplasty balloon. According to a preferred embodiment, the first lumen is in fluid communication with a balloon.  
           [0012]    In a preferred embodiment, the over-the-wire catheter further comprises a second tube including a proximal end, a distal end, and a second lumen extending therethrough. According to a preferred embodiment, the second tube is disposed within the elongate member or within the first tube. Preferably, the second lumen is a guidewire lumen adapted for receiving a guidewire.  
           [0013]    In a preferred embodiment, the over-the-wire catheter further comprises a first port and a second port. Preferably, the first port is disposed at the proximal end of the first tube and is in fluid communication with the first lumen. Preferably, the second port is disposed at the proximal end of the second tube and is in fluid communication with the second lumen. In a preferred embodiment, a seal is operatively affixed to the first port. Preferably, the seal prevents fluids and air from entering the first lumen. In an exemplary embodiment, the seal prevents fluids and air from entering a balloon, for example an angioplasty balloon.  
           [0014]    An alternative embodiment of the present invention comprises a vacuum seal for the proximal entry port of a balloon inflation lumen of a single-operator-exchange (SOE) catheter. According to a preferred embodiment, a single-operator-exchange catheter comprises an elongate member having a proximal end and a distal end. Preferably, a balloon is attached proximate the distal end.  
           [0015]    In a preferred embodiment, the single-operator-exchange catheter further comprises a first tube including a proximal end, a distal end, and a first lumen extending therethrough. Preferably, the first tube defines the outside surface of the elongate member, or alternatively, the first tube can be disposed within the elongate member. In an exemplary embodiment, the first lumen is an inflation lumen for a balloon, such as an angioplasty balloon. In an exemplary embodiment, the first lumen is in fluid communication with a balloon.  
           [0016]    In a preferred embodiment, the single-operator-exchange catheter further comprises a second tube including a proximal end, a distal end, and a second lumen extending therethrough. According to a preferred embodiment, the second tube is disposed within the first tube or within the elongate member. Preferably, the second lumen is a guidewire lumen adapted for receiving a guidewire.  
           [0017]    In a preferred embodiment, the single-operator-exchange catheter further comprises a first port and a second port. Preferably, the first port is disposed at the proximal end of the first tube and is in fluid communication with the first lumen. In a preferred embodiment, a seal is attached to the first port. Preferably, the seal prevents fluids and air from entering the first lumen. In an exemplary embodiment, the seal prevents fluids and air from entering a balloon, such as an angioplasty balloon.  
           [0018]    According to a preferred embodiment, the single-operator-exchange catheter further comprises a second port disposed at the proximal end of the second tube. Preferably, the second port is a guidewire port and is near the distal end of the single-operator-exchange catheter proximal to the balloon. Preferably, the second port in fluid communication with the second lumen.  
           [0019]    An exemplary embodiment of the present invention includes a preferred method of attaching a vacuum seal to a catheter. The first port is adapted to receive an attachment, such as a sealing device. In a preferred embodiment, a sealing device is adapted for sealing a first port of an over-the-wire or single-operator-exchange catheter. Preferably, the first port further comprises a first lumen and at least one flange. Preferably, the sealing device further comprises a distal end that engages a flange of the first port. Preferably, engagement of the distal end and the flange constitutes an air-tight seal.  
           [0020]    In a preferred embodiment, the sealing device further includes a vacuum lumen therethrough. Preferably, the vacuum lumen connects a chamber within the sealing device to a proximal end of the sealing device. Preferably, the proximal end is adapted for attaching to a vacuum source.  
           [0021]    In a preferred embodiment, the chamber is defined as the space formed between the sealing device and the first port when the sealing device is attached to the first port. Preferably, disposed within the chamber is a seal attachment means attached to a mid-region of the sealing device. Preferably, a seal is releasably attached to the seal attachment means. The seal attachment means is movable from a first position spaced apart from the flange to allow flow of air out of the inflation lumen to a second position wherein the seal engages the flange and seals the inflation lumen.  
           [0022]    In a preferred embodiment, the vacuum source may pull a vacuum through the vacuum lumen and inflation lumen when the sealing device is disposed on the flange. Application of a vacuum draws air out of the inflation lumen and balloon. The seal attachment means includes threads or other means for advancing the seal to engage the flange via the seal attachment means moving from the first position to the second position. The seal can include adhesive which bonds the seal to the flange when placed in contact. Preferably, the air pressure in the first lumen prior to the transfer of the seal is about zero. In an exemplary embodiment, after the transfer of the seal to the first port, the air pressure within the first lumen is about zero.  
           [0023]    Preferably, the seal, as positioned on the flange, is adapted for receiving additional preparation devices. For example, an additional preparation device may include a syringe for placing a substance into the first lumen. Preferably, the syringe comprises a needle capable of piercing the seal. In an exemplary embodiment, the seal comprises a self-resealing septum. In a preferred embodiment, after piercing the seal, the syringe can deliver a fluid for inflation through the needle into the first lumen. This relieves the vacuum from the lumen by displacing the voided volume with fluid, not air or other gas, and easily completes the preparation for use with certainty that gas is not present in the inflation lumen or balloon. Once the vacuum is relieved with fluid, the seal can be removed.  
           [0024]    In an alternative embodiment, the seal can be a self-resealing septum. In this embodiment, the seal is placed on the flange, followed by pulling vacuum through a needle which pierces the septum. When the inflation lumen and balloon are evacuated, the needle is pulled out of the self-resealing septum which maintains the vacuum.  
           [0025]    An exemplary embodiment of the present invention includes an alternative seal for use with over-the-wire and single-operator-exchange catheters. Preferably, a seal is attached to the first port and is capable of maintaining an air-tight seal with the first lumen. According to this embodiment, the seal includes a cap which can be releasably attached to the first port and over the seal.  
           [0026]    An alternative embodiment of the invention includes an alternative seal for use with over-the-wire and single-operator-exchange catheters. Preferably, a seal is attached to the first port and is capable of maintaining an air-tight seal with the first lumen. According to this embodiment, the seal is generally oversized relative to the first port. Preferably, an excess portion of the seal extends past at least one border of the first port. Preferably, the excess portion may be grasped by the fingers of a person or by a suitable grasping device so that the seal can be removed from the first port.  
           [0027]    An alternative embodiment of the invention includes an alternative seal for use with over-the-wire and single-operator-exchange catheters. Preferably, a seal is attached to the first port and is capable of maintaining an air-tight seal with the first lumen. According to this embodiment, the seal further comprises threads capable of releasably attaching the seal to the first port.  
           [0028]    An alternative embodiment of the invention includes an alternative seal for use with over-the-wire and single-operator-exchange catheters. Preferably, a seal is attached to the first port and is capable of maintaining an air-tight seal with the first lumen. According to this embodiment, the seal further comprises a tapered distal end capable of releasably attaching to the first port. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0029]    [0029]FIG. 1 is a partial cross-sectional view of a catheter including a vacuum seal for use with over-the-wire catheters according to a preferred embodiment of the invention;  
         [0030]    [0030]FIG. 2 is a partial cross-sectional view of a catheter including a vacuum seal for use with single-operator-exchange catheters according to a preferred embodiment of the invention;  
         [0031]    [0031]FIG. 3 is an illustration of a preferred mechanism for attaching a vacuum seal to a catheter, with the seal attachment means in a first position holding the seal spaced from the flange;  
         [0032]    [0032]FIG. 4 is an illustration of the mechanism for attaching a vacuum seal to a catheter of FIG. 3, with the seal attachment means in a second position holding the seal in sealing engagement with the flange;  
         [0033]    [0033]FIG. 5 is a diagrammatic view of a first vacuum seal according to a preferred embodiment of the invention;  
         [0034]    [0034]FIG. 6 is a diagrammatic plan view of a vacuum seal and a needle/syringe assembly according to a preferred embodiment of the invention;  
         [0035]    [0035]FIG. 7 is an enlarged view of an alternative vacuum seal and cap assembly according to a preferred embodiment of the invention;  
         [0036]    [0036]FIG. 8 is an enlarged view of an alternative vacuum seal according to a preferred embodiment of the invention;  
         [0037]    [0037]FIG. 9 is an enlarged view of an alternative vacuum seal according to a preferred embodiment of the invention; and  
         [0038]    [0038]FIG. 10 is an enlarged view of an alternative vacuum seal according to a preferred embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0039]    Referring now to the drawings wherein like reference numerals indicate like elements throughout the several views, FIG. 1 is a highly diagrammatic partial cross-sectional view of a catheter including a vacuum seal. The catheter is an over-the-wire catheter. According to a preferred embodiment, an over-the-wire catheter  10  comprises an elongate member  11  having a proximal end  12  and a distal end  14 . Preferably, a balloon  16  is attached proximate the distal end  14 . According to a preferred embodiment, elongate member  11  can be manufactured from materials including, but not limited to, metal, stainless steel, nickel alloys, nickel-titanium alloys, nitinol, hypodermic tubing, hollow cylindrical stock, polymers, plastics, and combinations thereof.  
         [0040]    In a preferred embodiment, catheter  10  further comprises a first tube  18  including a proximal end  20 , a distal end  22 , and a first lumen  24  extending therethrough. According to a preferred embodiment, first tube  18  is disposed within elongate member  11 . Preferably, first lumen  24  is an inflation lumen. In an alternative embodiment, the first tube and the elongate member may be a single tubular member. According to both embodiments, first lumen  24  is in fluid communication with balloon  16 . In use, first lumen  24  is filled with an inflation fluid to inflate the balloon  16 . Preferably, first tube  18  is manufactured from materials including, but not limited to, metal, stainless steel, nickel alloys, nickel-titanium alloys, nitinol, hypodermic tubing, hollow cylindrical stock, polymers, plastics, and combinations thereof.  
         [0041]    According to an exemplary embodiment, first tube  18  may include a chemical coating capable of binding air including carbon dioxide (CO 2 ), nitrogen (N 2 ), and oxygen (O 2 ). Preferably, the chemical coating may help maintain the air pressure within first tube  18  at about zero. The chemical coating may include substances sold commercially which are called “getters”. A person of ordinary skill in the art would be familiar with a getter and the use thereof according to multiple embodiments of the present invention.  
         [0042]    In a preferred embodiment, catheter  10  further comprises a second tube  26  including a proximal end  28 , a distal end  30 , and a second lumen  32  extending therethrough. Preferably, second tube  26  is disposed within elongate member  11 , or alternatively, disposed within the first tube. According to a preferred embodiment, second lumen  32  is a guidewire lumen adapted for receiving a guidewire  34 . Preferably, second tube  26  can be manufactured from materials including, but not limited to, metal, stainless steel, nickel alloys, nickel-titanium alloys, nitinol, hypodermic tubing, hollow cylindrical stock, polymers, plastics, and combinations thereof.  
         [0043]    In a preferred embodiment, catheter  10  further comprises a first port  36  and a second port  38 . Preferably, first port  36  is disposed at proximal end  20  of first tube  18  and is in fluid communication with first lumen  24 . Preferably, second port  38  is disposed at proximal end  28  of second tube  26  and is in fluid communication with second lumen  32 .  
         [0044]    In a preferred embodiment, a seal  40  is attached to first port  36 , covering the opening thereto. Preferably, seal  40  prevents fluids and air from entering and/or exiting first lumen  24 . According to a preferred embodiment, seal  40  may comprise a polymer, rubber, a rubber septum, or plastic. Polymers include, but are not limited to, thermoplastics, high performance engineering resins, polyethylene (PE), polypropylene (PP), polyvinylchloride (PVC), polyurethane, polytetrafluoroethylene (PTFE), polyetherether ketone (PEEK), polyimide, polyamide, polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polysufone, nylon, or perfluor(opropyl vinyl ether) (PFA).  
         [0045]    In one preferred embodiment, the seal  40  is a rubber septum, wherein a penetrating member can pass through the seal, for example a needle, that upon removal of the penetrating member, the seal will self-seal. In an exemplary embodiment, a needle can be used to deliver a fluid into first lumen  24 . Alternatively, a needle can be used to pull vacuum on the lumen when it has penetrated the seal. According to multiple embodiments of the present invention, self-seal is understood to mean that a seal, for example seal  40 , will remain substantially resistant to the passage of air or fluids after a selected penetrating member is removed from the seal.  
         [0046]    [0046]FIG. 2 is a highly diagrammatic partial cross-sectional view of a catheter having a vacuum seal. The catheter is a single-operator-exchange catheter. According to a preferred embodiment, a single-operator-exchange catheter  110  comprises an elongate member  111  having a proximal end  112  and a distal end  114 . Preferably, a balloon  116  is attached proximate the distal end  118 . According to a preferred embodiment, elongate member  111  is manufactured from materials including, but not limited to, metal, stainless steel, nickel alloys, nickel-titanium alloys, nitinol, hypodermic tubing, hollow cylindrical stock, polymers, plastics, and combinations thereof.  
         [0047]    In a preferred embodiment, catheter  110  further comprises a first tube  118  including a proximal end  120 , a distal end  122 , and a first lumen  124  extending therethrough. According to a preferred embodiment, first tube  118  is disposed within elongate member  111 . Alternatively, the elongate member and the first tube can be a single tubular member having a lumen therethrough. Preferably, first lumen  124  is an inflation lumen. According to this embodiment, first lumen  124  is in fluid communication with balloon  116 . In an exemplary embodiment, in use, first lumen  124  is filled with a fluid, for example an inflation fluid. Similar to what is disclosed above, first tube  118  is preferably manufactured from materials including, but not limited to, metal, stainless steel, nickel alloys, nickel-titanium alloys, nitinol, hypodermic tubing, hollow cylindrical stock, polymers, plastics, and combinations thereof.  
         [0048]    In a preferred embodiment, catheter  110  further comprises a second tube  126  including a proximal end  128 , a distal end  130 , and a second lumen  132  extending therethrough. Second tube  126  is disposed within elongate member  111  or within the first tube of a single tubular member. Preferably, second lumen  132  is a guidewire lumen adapted for receiving a guidewire  134 . In the depicted single-operator-exchange embodiment, the second tube  126  extends over only a portion of the length of the catheter. The proximal end of the second tube is located a short distance proximal of the balloon. Similar to what is disclosed above, second tube  126  is preferably manufactured from materials including, but not limited to, metal, stainless steel, nickel alloys, nickel-titanium alloys, nitinol, hypodermic tubing, hollow cylindrical stock, polymers, plastics, and combinations thereof.  
         [0049]    In a preferred embodiment, catheter  110  further comprises a first port  136  and a second port  138 . Preferably, first port  136  is disposed at proximal end  120  of first tube  118  and is in fluid communication with first lumen  124 . Preferably, second port  138  is disposed at proximal end  128  of second tube  126  and is in fluid communication with second lumen  132 . Preferably, second port  138  is guidewire port.  
         [0050]    In a preferred embodiment, a seal  140  is attached to first port  136 . Preferably, seal  140  prevents fluids and air from entering and/or exiting first lumen  124 . Similar to what is disclosed above, seal  140  preferably comprises a polymer, rubber, a rubber septum, or plastic.  
         [0051]    First tube  118  may include a chemical coating capable of binding air including carbon dioxide (CO 2 ), nitrogen (N 2 ), and oxygen (O 2 ). Preferably, the chemical coating may help maintain the vacuum within first tube  118  at an air pressure about zero. The chemical coating may include substances sold commercially called getters. A person of ordinary skill in the art would be familiar with a getter and the use thereof according to multiple embodiments of the present invention.  
         [0052]    [0052]FIG. 3 is an illustration of a preferred apparatus to be utilized in a method of attaching a vacuum seal  58  to a catheter port  236 . In a preferred embodiment, an attachment  44 , for example a sealing device, is adapted for sealing first port  236  comprising first lumen  234  and at least one flange  46 . Preferably, attachment  44  further comprises a distal end  48  that engages flange  46  of first port  236 . Preferably, engagement of distal end  48  and flange  46  constitutes an air-tight seal.  
         [0053]    In a preferred embodiment, attachment  44  further comprises a vacuum lumen  50 . Preferably, vacuum lumen  50  connects a chamber  52  to a proximal end  54  of attachment  44 . Preferably, proximal end  54  is adapted for attaching to a vacuum source  56 .  
         [0054]    In a preferred embodiment, chamber  52  is defined as the space formed between attachment  44  and first port  236  when attachment  44  is attached to first port  236 . Preferably, disposed within chamber  52  is a seal attachment means  58  attached to a movable member  60  of attachment  44 . Preferably, a seal  240  is releasably attached to seal attachment means  58 . Similar to what is disclosed above, seal  240  preferably comprises a polymer, rubber, a rubber septum, and plastic.  
         [0055]    As indicated in FIG. 3, a seal attachment means  58  is mounted on the end of a movable member  60 . The movable member  60  is depicted in FIG. 3 as being retracted away from the flange  46  so that when vacuum is pulled on the lumen  50 , air or other gas flows out of the inflation lumen of the catheter via the first port. In this first position of the movable member  60 , the catheter can be put under sufficient vacuum to remove most, if not substantially all, of the air or other gas from the inflation lumen and balloon of the catheter.  
         [0056]    [0056]FIG. 4 is an illustration of the preferred apparatus for attaching a vacuum seal to a catheter of FIG. 3 showing the way in which the seal  240  is placed on the flange  46 . With the apparatus as configured in FIG. 3, one may pull a vacuum through vacuum lumen  50 . Application of a vacuum forces air or gas out of the inflation lumen and balloon. Once sufficient vacuum has been pulled, movable member  60  is advanced, via threads, to the second position indicated in FIG. 4 to transfer seal  240  to first port  236 . Although threads are used to advance moveable member  60 , it is recognized that other means known by those in the art can be utilized. Preferably, the air pressure in first lumen  234  just prior to the transfer of seal  240  is about zero. In an exemplary embodiment, after the transfer of seal  240  to first port  236 , the air pressure within first lumen  234  is about zero.  
         [0057]    As discussed above, attachment  44  includes a device adapted to attach to the first port and that can evacuate the first lumen and attach a seal so that vacuum is retained.  
         [0058]    [0058]FIG. 5 depicts the sealed port upon removal of the attachment  44 . According to a preferred embodiment, first port  236  comprises first lumen  234 . Seal  240  is attached to first port  236  and is capable of maintaining an airtight seal within first lumen  234 .  
         [0059]    In preferred embodiments, the catheter having an evacuated and sealed inflation lumen is shipped to the end-user. However, before use, all that must be done is to fill the evacuated lumen with inflation fluid as vacuum is relieved. In a preferred embodiment, a device penetrates the seal to release an inflation fluid into the first lumen. In alternate embodiments, a device may be adapted to remove a seal and simultaneously connect to an inflation device and its fluid source. In an exemplary embodiment, a device may comprise an object that can pierce the seal, for example a needle. Alternatively, the attachment may comprise an object capable of breaking the seal. For example, the device may include a ramming portion that forcibly breaks the seal. In alternative embodiments of the current invention, a device may accomplish any combination of the features listed above.  
         [0060]    [0060]FIG. 6 is a diagrammatic view of a preferred apparatus and method of penetrating a vacuum seal to fill the lumen with inflation fluid according to a preferred embodiment of the invention. According to preferred embodiment, first port  236  comprises first lumen  234 . Preferably, seal  240  is attached to first port  236  and is capable of maintaining an airtight seal within first lumen  234 . Preferably, first port  236  is adapted for receiving a seal piercing device  144 . For example, device  144  may comprise a syringe  64  for placing a substance such as an inflation fluid into first lumen  236  to relieve the vacuum and fill the lumen and balloon with inflation fluid  68 . Preferably, syringe  64  comprises a needle  66  capable of piercing seal  240 . In a preferred embodiment, after piercing seal  240 , syringe  64  can deliver a fluid  68  through needle  66  into first lumen  234 . After the lumen is filled, seal  240  can be removed to facilitate attachment of another inflation device. Alternatively, the inflation device can incorporate means for piercing the seal when in use.  
         [0061]    The embodiment depicted in FIG. 6 also illustrates an alternative method for evacuating the inflation lumen of a catheter without utilizing the above-described seal placement device. In particular, the catheter port  236 , including a lumen  234  therein which is in fluid communication with the balloon, can have a seal  240  placed thereon while the lumen is still full of air or other gas. In this embodiment, the seal is made of a material that can be penetrated, but reseals upon removal of the penetrating device. Thus, the seal  240  is adhered to the flange of the port  236  and the penetrating member or needle  66  pierces the seal. A source of vacuum, such as the syringe  64  or other vacuum producing mechanism, is attached to the proximal end of the needle. Vacuum may then be drawn so that air or other gas is evacuated from the inflation lumen. When sufficient vacuum has been pulled, the needle  66  may be pulled back out of the seal  240  which then reseals to hold the lumen  234  as evacuated.  
         [0062]    [0062]FIG. 7 is an enlarged view of an alternative embodiment of a vacuum seal. According to this embodiment, first port  336  comprises first lumen  334 . Preferably, seal  340  is attached to first port  336  and is capable of maintaining a relatively air-tight seal within first lumen  334 . According to this embodiment, a cap  70  is releasably attached to first port  336  and over seal  340 . Similar to what is disclosed above, seal  340  preferably comprises a polymer, rubber, a rubber septum, and plastic. The cap assembly is incorporated to provide additional assurance that the lumen  334  will remain evacuated using any of the above methods of evacuation, even when the evacuated product is stored for an extended period. The use of the cap is especially useful with methods that include piercing the seal to pull vacuum, as it is believed that a perfect seal may not be maintained in some instances when the seal re-seals.  
         [0063]    [0063]FIG. 8 is a diagrammatic view of an alternative embodiment of a vacuum seal. According to this embodiment, first port  436  comprises first lumen  434 . Preferably, seal  440  is attached to first port  436  and is capable of maintaining an air-tight seal within first lumen  434 . Similar to what is disclosed above, seal  440  preferably comprises a polymer, rubber, a rubber septum, and plastic. According to this embodiment, seal  440  is generally oversized relative to first port  436 . Preferably, an excess portion  72  of seal  440  extends past at least one border  74  of first port  436 . Preferably, excess portion  72  may be grasped by the fingers of a person or by a suitable grasping device so that seal  440  can be removed from first port  436 . This facilitates seal removal after inflation fluid has been added to the evacuated lumen.  
         [0064]    [0064]FIG. 9 is a diagrammatic view of an alternative embodiment of a vacuum seal. According to this embodiment, first port  536  comprises first lumen  534 . Preferably, seal  540  is attached to first port  536  and is capable of maintaining an air-tight seal within first lumen  534 . Similar to what is disclosed above, seal  540  preferably comprises a polymer, rubber, a rubber septum, and plastic. According to this embodiment, seal  540  further comprises threads or ridges  76  capable of releasably attaching seal  540  to first port  536 .  
         [0065]    [0065]FIG. 10 is a diagrammatic view of an alternate embodiment of a vacuum seal. According to this embodiment, first port  636  comprises first lumen  634 . Preferably, seal  640  is attached to first port  636  and is capable of maintaining an air-tight seal within first lumen  634 . Similar to what is disclosed above, seal  640  preferably comprises a polymer, rubber, a rubber septum, and plastic. According to this embodiment, seal  640  further comprises a tapered distal end  78  capable of releasably attaching to first port  636 .  
         [0066]    Numerous advantages of the invention covered by this document have been set forth in the foregoing description. It will be understood, however, that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of steps without exceeding the scope of the invention. The invention&#39;s scope is, of course, defined in the language in which the appended claims are expressed.