Patent Publication Number: US-2019183557-A1

Title: Compensation assembly for fluid injection line of cryogenic balloon catheter system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Provisional Application No. 62/607,863, filed on Dec. 19, 2017, and entitled “COMPENSATION ASSEMBLY FOR FLUID INJECTION LINE OF CRYOGENIC BALLOON CATHETER SYSTEM”. As far as permitted, the content of U.S. Provisional Application No. 62/607,863 is incorporated in its entirety herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to medical devices and methods for treating cardiac arrhythmias. More specifically, the disclosure relates to devices and methods for cardiac cryoablation. 
     BACKGROUND 
     Cardiac arrhythmias, such as atrial fibrillation, involve an abnormality in the electrical conduction of the heart and are a leading cause of stroke, heart disease, and sudden cardiac death. Treatment options for patients with arrhythmias include medications, implantable devices, and catheter ablation of cardiac tissue. 
     Catheter ablation involves delivering ablative energy to tissue inside the heart to block aberrant electrical activity from depolarizing heart muscle cells out of synchrony with the heart&#39;s normal conduction pattern. The procedure is performed by positioning the tip of an energy delivery catheter adjacent to diseased or targeted tissue in the heart. The energy delivery component of the system is typically at or near the most distal (farthest from the operator) portion of the catheter, and often at the tip of the device. Various forms of energy are used to ablate diseased heart tissue. These can include balloon cryotherapy which uses cryoballoons (also sometimes referred to herein as “balloon catheters”), ultrasound and laser energy, and radio frequency, to name a few. Atrial fibrillation is one of the most common arrhythmias treated using balloon cryotherapy. Atrial fibrillation is typically treated by pulmonary vein isolation, a procedure that removes unusual electrical conductivity in the pulmonary vein. In the earliest stages of the disease, paroxysmal atrial fibrillation, the treatment strategy involves isolating the pulmonary vein(s) from the left atrial chamber. Recently, the use of balloon cryotherapy procedures to treat atrial fibrillation has increased. In part, this stems from ease of use, shorter procedure times and improved patient outcomes. 
     In the case of balloon cryotherapy, one or more cryoballoons are maneuvered through the vascular system of the patient, and are ultimately positioned near or against targeted cardiac tissue. Once in position, the cryoballoons are inflated. Cryogenic fluid, such as liquid nitrous oxide, is delivered through a fluid injection line to an interior of the inflated cryoballoon(s) to cause tissue necrosis of the target cardiac tissue, which renders the tissue incapable of conducting electrical signals. Once the target tissue has been necrosed, the cryoballoons are then deflated and the balloon catheter is removed from the patient&#39;s body. 
     In many balloon catheters, the overall length of the balloon catheter can change during inflation and/or deflation. For example, while deflated, the cryoballoons are more elongated in length as the cryoballoons are stretched out. In these types of balloon catheters, during inflation and deflation of the cryoballoon(s), the overall length of the fluid injection line may need to be adjusted to maintain a distal end of the fluid injection line in proper position relative to the cryoballoon(s) during inflation and deflation. There is a continuing need for improved cryoablation balloon catheter designs. 
     SUMMARY 
     The present disclosure is directed toward an injection line compensation assembly for a cryogenic balloon catheter system. The cryogenic balloon catheter system includes a cryoballoon and a guidewire lumen that extends through and is secured to the cryoballoon. In various embodiments, the injection line compensation assembly includes an injection line receiver and a fluid injection line. The injection line receiver is fixedly secured to the guidewire lumen so that movement of the guidewire lumen moves the injection line receiver. Further, the injection line receiver can include an interior chamber. The fluid injection line delivers a cryogenic fluid to the interior chamber of the injection line receiver. In certain embodiments, the fluid injection line extends into the injection line receiver and allows relative movement between the fluid injection line and the injection line receiver. 
     In various embodiments, the fluid injection line is not affixed to the injection line receiver. 
     In some embodiments, the fluid injection line is not affixed to the guidewire lumen. 
     In certain embodiments, the injection line receiver includes a plenum. In some such embodiments, the plenum substantially encircles a portion of the guidewire lumen. 
     In various embodiments, the injection line receiver includes a plurality of fluid ports that allow cryogenic fluid to exit the injection line receiver into the cryoballoon. 
     In some embodiments, the injection line receiver includes one or more injection line sealers that are positioned around a portion of the fluid injection line. In certain embodiments, the injection line sealer can include an O-ring. In various embodiments, the injection line sealer can be formed from a resilient material. In some embodiments, the injection line receiver can include a plurality of injection line sealers that are each positioned around a portion of the fluid injection line. 
     In certain embodiments, the injection line receiver is slidably movable relative to the fluid injection line. 
     In another embodiment, the injection line compensation assembly includes an injection line receiver and a fluid injection line. In certain embodiments, the injection line receiver is positioned within the handle assembly. Further, the injection line receiver can include an interior chamber. The fluid injection line can be at least partially positioned within the interior chamber of the injection line receiver. In various embodiments, the fluid injection line can be configured to receive a cryogenic fluid within the interior chamber. The fluid injection line can be fixed relative to at least a portion of the guidewire lumen so that movement of the guidewire lumen moves the fluid injection line relative to the injection line receiver. 
     In various embodiments, the fluid injection line can be movably secured to the injection line receiver. In certain embodiments, the injection line receiver can include one or more injection line sealers that are positioned around a portion of the fluid injection line. 
     In certain embodiments, the injection line sealer can include an O-ring. In various embodiments, the injection line sealer can be formed from a resilient material. In some embodiments, the injection line receiver can include a plurality of injection line sealers that are each positioned around a portion of the fluid injection line. 
     While multiple embodiments are disclosed, still other embodiments of the present disclosure will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the disclosure. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simplified schematic side view illustration of a patient and an embodiment of a cryogenic balloon catheter system having features of the present disclosure; 
         FIG. 2  is a simplified side view of a portion of the patient and an embodiment of a portion of the cryogenic balloon catheter system including one embodiment of an injection line compensation assembly; 
         FIG. 3A  is a partially cutaway side view of a portion of the cryogenic balloon catheter system, including a portion of a guidewire lumen and a portion of one embodiment of the injection line compensation assembly, shown in an extended position; 
         FIG. 3B  is a partial cutaway side view of a portion of the guidewire lumen and a portion of the injection line compensation assembly illustrated in  FIG. 3A , shown in a retracted position; 
         FIG. 4A  is a perspective view of one embodiment of a portion of the injection line compensation assembly, including an injection line receiver; 
         FIG. 4B  is a cross-sectional view of the injection line receiver taken on line  4 B- 4 B in  FIG. 4A ; and 
         FIG. 5  is a partially cutaway perspective view of a portion of the cryogenic balloon catheter system, including a handle assembly and a portion of another embodiment of the injection line compensation assembly. While the disclosure is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the disclosure to the particular embodiments described. On the contrary, the disclosure is intended to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure as defined by the appended claims. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present disclosure are described herein in the context of a balloon catheter steering assembly for a cryogenic balloon catheter system. Those of ordinary skill in the art will realize that the following detailed description of the present disclosure is illustrative only and is not intended to be in any way limiting. Other embodiments of the present disclosure will readily suggest themselves to such skilled persons having the benefit of this disclosure. Reference will now be made in detail to implementations of the present disclosure as illustrated in the accompanying drawings. 
     In the interest of clarity, not all of the routine features of the implementations described herein are shown and described. It will, of course, be appreciated that in the development of any such actual implementation, numerous implementation-specific decisions must be made in order to achieve the developer&#39;s specific goals, such as compliance with application-related and business-related constraints, and that these specific goals will vary from one implementation to another and from one developer to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of engineering for those of ordinary skill in the art having the benefit of this disclosure. 
       FIG. 1  is a schematic side view illustration of one embodiment of a cryogenic balloon catheter system  10  for use with a patient  12 , which can be a human being or an animal. The design of the cryogenic balloon catheter system  10  can be varied. In certain embodiments such as the embodiment illustrated in  FIG. 1 , the cryogenic balloon catheter system  10  can include one or more of a control system  14 , a fluid source  16 , a balloon catheter  18 , a handle assembly  20 , a control console  22  and a graphical display  24 . It is understood that although  FIG. 1  illustrates the structures of the cryogenic balloon catheter system  10  in a particular position, sequence and/or order, these structures can be located in any suitably different position, sequence and/or order than that illustrated in  FIG. 1 . It is also understood that the cryogenic balloon catheter system  10  can include fewer or additional components than those specifically illustrated and described herein. 
     In various embodiments, the control system  14  can control release and/or retrieval of a cryogenic fluid  26  to and/or from the balloon catheter  18 . In various embodiments, the control system  14  can control activation and/or deactivation of one or more other processes of the balloon catheter  18 . Additionally, or in the alternative, the control system  14  can receive data and/or other information (hereinafter sometimes referred to as “sensor output”) from various structures within the cryogenic balloon catheter system  10 . In some embodiments, the control system  14  can assimilate and/or integrate the sensor output, and/or any other data or information received from any structure within the cryogenic balloon catheter system  10 . Additionally, or in the alternative, the control system  14  can control positioning of portions of the balloon catheter  18  within the body of the patient  12 , and/or can control any other suitable functions of the balloon catheter  18 . 
     The fluid source  16  contains the cryogenic fluid  26 , which is delivered to the balloon catheter  18  with or without input from the control system  14  during a cryoablation procedure. The type of cryogenic fluid  26  that is used during the cryoablation procedure can vary. In one non-exclusive embodiment, the cryogenic fluid  26  can include liquid nitrous oxide. However, any other suitable cryogenic fluid  26  can be used. 
     The balloon catheter  18  is inserted into the body of the patient  12 . In one embodiment, the balloon catheter  18  can be positioned within the body of the patient  12  using the control system  14 . Alternatively, the balloon catheter  18  can be manually positioned within the body of the patient  12  by a health care professional (also sometimes referred to herein as an “operator”). In certain embodiments, the balloon catheter  18  is positioned within the body of the patient  12  utilizing the sensor output from the balloon catheter  18 . In various embodiments, the sensor output is received by the control system  14 , which then can provide the operator with information regarding the positioning of the balloon catheter  18 . Based at least partially on the sensor output feedback received by the control system  14 , the operator can adjust the positioning of the balloon catheter  18  within the body of the patient  12 . 
     The handle assembly  20  is handled and used by the operator to operate, position and control the balloon catheter  18 . The design and specific features of the handle assembly  20  can vary to suit the design requirements of the cryogenic balloon catheter system  10 . In the embodiment illustrated in  FIG. 1 , the handle assembly  20  is separate from, but in electrical and/or fluid communication with the control system  14 , the fluid source  16  and/or the graphical display  24 . In some embodiments, the handle assembly  20  can integrate and/or include at least a portion of the control system  14  within an interior of the handle assembly  20 . It is understood that the handle assembly  20  can include fewer or additional components than those specifically illustrated and described herein. 
     In the embodiment illustrated in  FIG. 1 , the control console  22  includes the control system  14 , the fluid source  16  and the graphical display  24 . However, in alternative embodiments, the control console  22  can contain additional structures not shown or described herein. Still alternatively, the control console  22  may not include various structures that are illustrated within the control console  22  in  FIG. 1 . For example, in one embodiment, the control console  22  does not include the graphical display  24 . 
     The graphical display  24  provides the operator of the cryogenic balloon catheter system  10  with information that can be used before, during and after the cryoablation procedure. The specifics of the graphical display  24  can vary depending upon the design requirements of the cryogenic balloon catheter system  10 , or the specific needs, specifications and/or desires of the operator. 
     In one embodiment, the graphical display  24  can provide static visual data and/or information to the operator. In addition, or in the alternative, the graphical display  24  can provide dynamic visual data and/or information to the operator, such as video data or any other data that changes over time. Further, in various embodiments, the graphical display  24  can include one or more colors, different sizes, varying brightness, etc., that may act as alerts to the operator. Additionally, or in the alternative, the graphical display  24  can provide audio data or information to the operator. 
       FIG. 2  is a simplified side view of a portion of the patient  212  and an embodiment of a portion of the cryogenic balloon catheter system  210 . In this embodiment, the cryogenic balloon catheter system  210  includes a balloon catheter  218 , a handle assembly  220  and an injection line compensation assembly  228  (also sometimes referred to herein as the “compensation assembly”). 
     The design of the balloon catheter  218  can be varied to suit the design requirements of the cryogenic balloon catheter assembly  210 . In this embodiment, the balloon catheter  218  includes one or more of a catheter shaft  230 , one or more balloons including at least one of an inner balloon  232  and an outer balloon  234 , a guidewire lumen  236  and a guidewire  238 . It is understood that the balloon catheter  218  can include other structures as well. However, for the sake of clarity, these other structures have been omitted from  FIG. 2 . 
     The catheter shaft  230  is positioned coaxially over the guidewire lumen  236 . The design of the catheter shaft  230  can vary depending upon the design requirements of the balloon catheter  218 . In one embodiment, a balloon proximal region  232 P (nearer to the handle assembly  220 ) of the balloon(s)  232 ,  234  is secured to the catheter shaft  230 , and a balloon distal region  232 D (further from the handle assembly  220 ) of the balloon(s)  232 ,  234  is secured to the guidewire lumen  236 . 
     The guidewire lumen  236  extends from the handle assembly  220  in a direction away from the handle assembly  220 . The guidewire lumen can be mechanically (or otherwise) moved in a direction toward (retraction) or away (extension) from the handle assembly  220  to either extend or contract the balloon(s)  232 ,  234 , since the distal region of the balloon(s)  232 ,  234 , is secured to the guidewire lumen  236  and the proximal region of the balloon(s) is secured to the catheter shaft  230 . 
     In the embodiment illustrated in  FIG. 2 , the balloon catheter  218  is positioned within the circulatory system  240  of the patient  212 . The guidewire  238  and a portion of the guidewire lumen  236  are moved into a pulmonary vein  242  of the patient  212 , and the catheter shaft  230  and the balloons  232 ,  234  are moved along the guidewire  238  to an ostium  244  of the pulmonary vein  242 . 
     The design of the handle assembly  220  can vary. In the embodiment illustrated in  FIG. 2 , the handle assembly  220  can be used by an operator of the cryogenic balloon catheter system  210  to move portions of the balloon catheter  218 . For example, the handle assembly  220  can include one or more steering mechanisms (not shown) that can be manipulated to steer the guidewire lumen  236  toward the desired pulmonary vein  242 . The handle assembly  220  can have one or more additional or alternative suitable functions. 
     The injection line compensation assembly  228  compensates for changes in an overall length of the guidewire lumen  236  that extends away from the handle assembly  220  during extension and/or retraction of the guidewire lumen  236 . In the embodiment illustrated in  FIG. 2 , the compensation assembly  228  includes a fluid injection line  246  and an injection line receiver  248 . 
     The fluid injection line  246  delivers the cryogenic fluid  26  (illustrated in  FIG. 1 ) to the cryoballoon(s)  232 ,  234 , during a cryoablation procedure. The design of the fluid injection line  246  can vary. In one embodiment, the fluid injection line  246  is a tubular structure. In various embodiments, at least a portion of the fluid injection line  246  extends from the handle assembly  220 , along or otherwise adjacent to the guidewire lumen  236 , to a balloon interior  250 . The fluid injection line  246  can be formed from any suitably flexible material. For example, in one non-exclusive embodiment, the fluid injection line  246  can be formed at least partially from nitinol. 
     In the embodiment illustrated in  FIG. 2 , the injection line receiver  248  movably receives a portion of the fluid injection line  246 . The design of the injection line receiver  248  can vary. In one embodiment, the injection line receiver  248  can include a plenum or manifold-type of structure, as provided in greater detail herein. In the embodiment illustrated in  FIG. 2 , the injection line receiver  248  is affixed to, secured to, and moves in concert with, the guidewire lumen  236 . In other words, as the guidewire lumen  236  extends and/or retracts during a cryoablation procedure, the injection line receiver  248  likewise moves with the guidewire lumen  236 . Thus, the injection line receiver  248  can slidably move relative to the fluid injection line  246 , which in various embodiments, is not secured to the guidewire lumen  236 . Stated another way, the injection line receiver  248  can move forward and/or aft in a slidable manner over a portion of the fluid injection line  246 . In certain embodiments, the cryogenic fluid  26  exits the fluid injection line  246  into the injection line receiver  248 . The injection line receiver  248  can then distribute the cryogenic fluid  26  to the balloon interior  250  as needed during the cryoablation procedure, as provided in greater detail herein. 
       FIG. 3A  is a partially cutaway side view of a portion of the cryogenic balloon catheter system  310  including a portion of a guidewire lumen  336  and a portion of one embodiment of the injection line compensation assembly  328 , shown in an extended position. In this embodiment, the compensation assembly  328  includes the fluid injection line  346  and the injection line receiver  348 . 
     In the extended position, the guidewire lumen  336  is extended distally away from the handle assembly  220  (illustrated in  FIG. 2 ). In this position, at least a portion of the cryoballoon  232  (illustrated in  FIG. 2 ) is likewise extended distally away from the handle assembly  220 . Stated another way, the cryoballoon  232  is “stretched” lengthwise either prior to, or after ablation. 
     The fluid injection line  346  includes a line distal end  352  that is positioned within the injection line receiver  348 . The line distal end  352  can have a wider or otherwise larger dimension than other portions of the fluid injection line  346 , which maintains a positioning of the line distal end  352  within the injection line receiver  348 , as provided in greater detail herein. Cryogenic fluid  326  (illustrated in  FIG. 3B ) can exit the fluid injection line  346  during inflation of the cryoballoon  232  and/or at other times during the cryoablation procedure. 
     In the embodiment illustrated in  FIG. 3A , the injection line receiver  348  receives the line distal end  352  of the fluid injection line  346 . The design of the injection line receiver  348 , including the shape, size, materials used, and specific features, can vary. In the embodiment illustrated in  FIG. 3A , the injection line receiver  348  can be a plenum or a manifold that receives and distributes the cryogenic fluid  326  to the balloon interior  250  (illustrated in  FIG. 2 ). In this embodiment, the injection line receiver  348  is secured to the guidewire lumen  336 , and is positioned to substantially encircle at least a portion of the guidewire lumen  336 . With this design, the guidewire lumen  336  and the injection line receiver  348  move in unison relative to the fluid injection line  346 . In one embodiment, the injection line receiver  348  can include one or more of a receiver body  354  and one or more injection line sealers  356  (two injection line sealers are illustrated in  FIG. 3A ). 
     The receiver body  354  defines a mostly enclosed interior chamber  476  (illustrated in  FIG. 4B ) into which the cryogenic fluid  326  is delivered prior to being expelled into the balloon interior  250 . In one embodiment, the receiver body  354  can be substantially cylindrical in shape. Alternatively, the receiver body  354  can be somewhat conical, frusto-conical, spherical, or bullet-shaped, as non-exclusive examples. Still alternatively, the receiver body  354  can have any other suitable shape, configuration or geometry. In the embodiment illustrated in  FIG. 3A , the receiver body  354  includes one or more exit ports  358  through which the cryogenic fluid  326  exits the injection line receiver  348  into the cryoballoon  232 . The exit ports  358  can be arranged in any suitable pattern to increase the likelihood of even distribution of the cryogenic fluid  326  in a desired portion of the cryoballoon  232 . Further, the shape of each exit port  358  can be tailored to increase the likelihood of even distribution of the cryogenic fluid  326  in a desired portion of the cryoballoon  232 . 
     The injection line sealer(s)  356  form a seal around the fluid injection line  346  and within a portion of the injection line receiver  348  to inhibit cryogenic fluid  326  from exiting the receiver body  354  through any avenue other than the exit ports  358 . Additionally, or in the alternative, the injection line sealer  356  inhibits the fluid injection line  346  from being completely removed from the injection line receiver  348 , given the enlarged line distal end  352 . In the embodiment illustrated in  FIG. 3A , the injection line sealers  356  can be annular or somewhat washer shaped. Alternatively, the injection line sealers  356  can have any other suitable shape. In one embodiment, the injection line sealers  356  can be formed from a resilient material such as rubber, plastic, or the like. 
       FIG. 3B  is a partially cutaway side view of a portion of the cryogenic balloon catheter system  310  including a portion of a guidewire lumen  336  and a portion of one embodiment of the injection line compensation assembly  328 , shown in a retracted position. 
     In the retracted position, the guidewire lumen  336  is retracted toward the handle assembly  220  (illustrated in  FIG. 2 ). In this position, at least a portion of the cryoballoon  232  (illustrated in  FIG. 2 ) is likewise retracted toward the handle assembly  220  in preparation for ablation. Stated another way, the cryoballoon  232  is contracted lengthwise in preparation for and/or during ablation. 
     In this embodiment, the guidewire lumen  336  and the injection line receiver  348  move substantially in unison relative to the fluid injection line  346 . To move from the extended position illustrated in  FIG. 3A  to the retracted position illustrated in  FIG. 3B , the guidewire lumen  336  is pulled or otherwise moved in a direction indicated by arrow  360 . Because the injection line receiver  348  is secured or otherwise connected to the guidewire lumen  336 , moving the guidewire lumen  336  also simultaneously moves the injection line receiver  348  in a direction  360 , for example. 
     Conversely, to move from the retracted position illustrated in  FIG. 3B  to the extended position illustrated in  FIG. 3A , the guidewire lumen  336  is pushed or otherwise moved in a direction indicated by arrow  362  (illustrated in  FIG. 3A ). Because the injection line receiver  348  is secured or otherwise connected to the guidewire lumen  336 , moving the guidewire lumen  336  also simultaneously moves the injection line receiver  348  in a direction  362 , for example. 
       FIG. 4A  is a perspective view of one embodiment of a portion of the injection line compensation assembly  428 , including one embodiment of the injection line receiver  448 . The fluid injection line  346  has been omitted from  FIG. 4A  for clarity. In this embodiment, the injection line receiver  448  includes a receiver body  454 , one or more injection line sealers  456  (illustrated in phantom in  FIG. 4A ), one or more exit ports  458 , a guidewire lumen receiver  464 , an injection line aperture  466 , a body proximal end  468  and a body distal end  470 . The receiver body  454  can have a configuration that is somewhat similar to that previously described herein. Alternatively, the receiver body  454  can have a different configuration. In this embodiment, the exit ports  458  are positioned at a plurality of locations around a circumference of the receiver body  454 . 
     The guidewire lumen receiver  464  receives the guidewire lumen  336  (illustrated in  FIG. 3A , for example). The injection line receiver  448  can be secured to the guidewire lumen  336  by any suitable manner. For example, the injection line receiver  448  can be adhered to the guidewire lumen  336  with an adhesive material. Alternatively, the injection line receiver  448  can be welded to the guidewire lumen  336 , as one non-exclusive embodiment. 
     The injection line aperture  466  allows access or insertion of the fluid injection line  346  (illustrated in  FIG. 3A ) into an interior chamber  476  (illustrated in  FIG. 4B ) of the injection line receiver  448 . 
       FIG. 4B  is a cross-sectional view of the injection line receiver  448  taken on line  4 B- 4 B in  FIG. 4A . In this embodiment, the injection line receiver  448  includes an outer wall  472 , an inner wall  474  and an interior chamber  476  that is defined by the space formed between the outer wall  472  and the inner wall  474 . It is understood that the configuration of the outer wall  472 , the inner wall  474  and the interior chamber  476  can be varied from that illustrated in  FIG. 4B . 
       FIG. 5  is a partially cutaway perspective view of a portion of an embodiment of the cryogenic balloon catheter system  510 , including a handle assembly  520  and a portion of another embodiment of the injection line compensation assembly  528 . The design of the handle assembly  520  can vary to suit the design requirements of the cryogenic balloon catheter system  510 . In this embodiment, at least a portion of the injection line compensation assembly  528  can be positioned substantially within the handle assembly  520 . 
     For example, in the embodiment illustrated in  FIG. 5 , the compensation assembly  528  includes the fluid injection line  546  and an injection line receiver  548 . In one embodiment, the fluid injection line  546  can include a line distal end (not shown in  FIG. 5 ) and a line proximal end  578 . The line distal end extends into the cryoballoon interior  250  (illustrated in  FIG. 2 , for example). However, in this embodiment, the line distal end of the fluid injection line  546  is secured, coupled or otherwise attached to the guidewire lumen  336  (illustrated in  FIG. 3A , for example). With this design, the fluid injection line  546  moves in concert with the guidewire lumen  336 . 
     The line proximal end  578  is positioned within the injection line receiver  548  in the handle assembly  520 . Because the fluid injection line  546  moves in concert with the guidewire lumen  336 , the line proximal end  578  moves within the injection line receiver  548  in both a forward and an aft direction shown by arrow  580 . 
     In this embodiment, the injection line receiver  548  can include one or more injection line sealers  556  (two injection line sealers  556  are illustrated in  FIG. 5 ) that seal an interior chamber  576  to allow a more consistent flow of cryogenic fluid  26  (illustrated in  FIG. 1 ) to the line proximal end  578  while inhibiting leakage of cryogenic fluid  26  to unwanted regions of the cryogenic balloon catheter system  510 . 
     It is understood that although a number of different embodiments of the cryogenic balloon catheter system and the injection line compensation assembly have been illustrated and described herein, one or more features of any one embodiment can be combined with one or more features of one or more of the other embodiments, provided that such combination satisfies the intent of the present disclosure. 
     Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present disclosure. For example, while the embodiments described above refer to particular features, the scope of this disclosure also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present disclosure is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the claims, together with all equivalents thereof.