Patent Publication Number: US-7905879-B2

Title: Cryoablation catheter handle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of pending application Ser. No. 10/706,525, filed Nov. 12, 2003, by Marwan Abboud, et al., entitled CRYOABLATION CATHETER HANDLE, now Pat. No. 7,118,565, issued Oct. 10, 2006, which application is a continuation of and claims priority to application Ser. No. 10/202,991, filed Jul. 25, 2002, by Marwan Abboud, et al., entitled CRYOABLATION CATHETER HANDLE, now Pat. No. 6,746,445, issued Jun. 08, 2004, which application is a continuation of and claims priority from U.S. patent application Ser. No. 09/556,042, filed Apr. 21, 2000, by Marwan Abboud, et al., entitled CRYOABLATION CATHETER HANDLE, now Pat. No. 6,440,126, issued Aug. 27, 2002, which application claims priority from U.S. Provisional Patent Application Ser. No. 60/130,538, filed Apr. 21, 1999, by Marwan Abboud, et al., entitled CRYOABLATION CATHETER HANDLE, now lapsed, the totality of all of which are incorporated herein by reference. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
     Not applicable. 
     FIELD OF THE INVENTION 
     This invention relates to catheters, and more particularly to handles and connectors for cryogenic catheters. 
     BACKGROUND OF THE INVENTION 
     A cryocatheter can generally be described as an elongate, slender, flexible body that is capable of delivering extreme cold to provide a medically therapeutic effect. Such a catheter can be a part of a system that includes several components, such as a console, an umbilical, a cryoblation catheter and a handle. 
     The console houses the electronics and software for controlling an ablation procedure. Additionally, the console controls delivery of a refrigerant through the umbilical to the catheter and recovery of the refrigerant from the catheter. 
     The umbilical connecting the catheter and handle to the console provides mechanical connections for refrigerant transport and electrical connection for electrical devices and sensors. The handle, in addition to providing an appropriate graspable structure, can include controls for catheter steering, as well as other catheter functions. 
     Known cryocatheter systems provide a unitary handle and catheter which is intended for a single use. As with other devices, attention to the percentage and content of a system that is disposable (or that which must be disposed of for sanitary reasons), as well as attention to the cost of replacement items, can have a substantial effect on the cost of acquisition and operation of the system. Thus, if possible, it would help to reduce cost of the system if only the catheter (or a portion thereof) were disposable and, under most circumstances, the handle were available for reuse. 
     Ideally, the inclusion of disposable system elements does not compromise system performance or patient safety. However, known attempts to provide disposable catheter elements have been less than ideal. For example, providing a catheter that is removable from the handle requires not only connection to refrigerant, steering elements and electrical elements, but also a creation of a fluid-tight seal at the catheter/handle interface. Not only can it be tedious to make such connections, known devices with this type of feature have not proved to be acceptable with respect to either performance or safety. It would therefore be desirable to provide a cryocatheter and handle that provides the benefits of a disposable component and which is easy to use, without safety or performance limitations. 
     SUMMARY OF THE INVENTION 
     The present invention provides a cyrocatheter system having a two-part handle that is easy to connect and use; but the system does not compromise safety and performance requirements. 
     In an exemplary embodiment, a cryocatheter system includes a first handle portion having a proximal end, a distal end, a first fluid flow path, and a second fluid flow path; a second handle portion having a proximal end, a distal end, a first fluid flow path, and a second fluid flow path; and a catheter having a proximal end, a distal end, a first fluid flow path, and a second fluid flow path. The distal end of the first handle portion is matable with the proximal end of the second handle portion to place the respective first and second fluid flow paths of each handle portion in fluid communication; and the distal end of the second handle portion is matable with the proximal end of the catheter to place the respective first and second fluid flow paths of the second handle portion and the catheter in fluid communication. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of the present invention, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, wherein: 
         FIG. 1  illustrates a cryocatheter system generally; 
         FIG. 2  illustrates an exemplary embodiment of a handle as shown in  FIG. 1 , wherein the two handle portions are not mated; 
         FIG. 2A  depicts the first and second handle portions of  FIG. 2  in a mated state; 
         FIG. 3  shows an alternative embodiment of a two-part handle; 
         FIG. 4  is an exploded view of a two-part co-axial handle; 
         FIG. 5  is a sectional view of the two-part co-axial handle of  FIG. 4  in a partially mated state; 
         FIG. 6  illustrates additional features of the handle of  FIG. 4  in an exploded cut-away view; 
         FIG. 7  is a sectional view of another embodiment of a co-axial connection; and 
         FIG. 8  is yet another embodiment of a co-axial connection. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  depicts a cryocatheter system in accordance with the invention. The system includes a catheter  10 , such as those disclosed in U.S. Pat. Nos. 5,899,898 and 5,899,899 to Arless, which are incorporated herein by reference. The system also includes a handle  12  having a first portion  14  and a second portion  16 . First and second umbilicals  18  and  20 , respectively, connect the second portion  16  of the handle  12  to a console  22 . The first umbilical  18  provides a path for a liquid or gas refrigerant to be transferred between the console  22  and the handle  12 ; and the second umbilical  20  provides a signal path, such as for electrical signals, between the console  22  and the handle. Additional umbilicals can be provided as required, and the functions of more than one umbilical can be provided in a single, multifunction umbilical. Further, additional devices, such as a connector box  24  can be placed in electrical communication with an umbilical. As shown in  FIG. 1 , the connector box  24  provides for connection to ECG apparatus (not shown). Also, one or more of the umbilicals can be divisible into two or more portions as shown in  FIG. 1 , wherein the first umbilical includes portion  18  and  18 ′, and the second umbilical includes portions  20  and  20 ′. 
     Referring now to  FIG. 2 , additional details of an exemplary two-part handle  12  are discussed in greater detail. A first handle portion  14  is shown mated to a cryocatheter  10  and a second handle portion  16  is shown mated to a single, multipurpose umbilical  26 . The first handle portion  14  defines or includes a portion of a first fluid pathway  28  and a portion of a second fluid pathway  30 . The second handle portion  16  defines or contains a second portion of the first fluid pathway  28 ′ and a second portion of the second fluid pathway  30 ′. When the first and second portions of the first and second fluid pathways are mated, as shown in  FIG. 2A , continuous fluid paths are provided. Similarly, the first handle portion  14  includes a portion of one or more electrical or fiber-optic lines  31  and the second handle portion  16  includes a second portion of the one or more electrical or fiber-optic lines  31 ′. Further, the first handle portion  14  includes a portion of one or more steering elements, such a pull wire  33  and the second handle portion  16  includes a second portion of the steering elements  33 ′. 
     The first and second handle portions, as well as the first and second fluid pathways, one or more electrical or fiber-optic lines, and one or more steering elements are held together by complimentary locking elements  32  and  34  as is known in the art, such as locking clips, bayonet, or twist-lock. Similarly, the fluid paths are mated with couplings, the wires with electrical connectors, and the steering elements with mechanical connectors. Thus, in the exemplary embodiment, the catheter  10  can be disconnected from the umbilical  14  and discarded, while allowing the first handle portion  18 , which can include steering mechanisms and other controls, to be retained for further use. 
     Whereas  FIG. 2  shows a steering actuator, such as a thumb wheel, for selectively positioning a steering element in the second portion  16  of the handle  12 ,  FIG. 3  shows an arrangement where the steering actuator  36  is located in the first portion  14 . Additional features visible in  FIG. 3  include a blood sensor  38  located and configured in such a manner so as to detect blood being withdrawn from the catheter  10  through a low pressure or vacuum exhaust line  40  along with refrigerant injected through a supply tube  42 . Also shown are electrical controls  44  in communication with electrical wires  46 . 
     In addition to the above features, the refrigerant injection and low pressure or vacuum return lines can be configured coaxially either in an umbilical or in the handle as shown in  FIG. 4 . In this illustration an umbilical  48 , a first connector  50  or handle portion, a second connector  52  or handle portion, and second umbilical  54  or catheter are shown. The umbilical  48  includes an outer tube  56  and an inner tube  58 . In the exemplary embodiment, the inner tube  58  provides a path for fluid (e.g., refrigerant) under positive pressure, whereas the outer tube  56  provides a path for fluid under reduced or low pressure (e.g., in connection to a vacuum pump  55 ). Thus, if a leak should occur at some point along the inner tube  58  or its connections to other components, the low pressure environment allows the leak to be contained, thereby preventing refrigerant from escaping the umbilical  48 . Additional safety is provided by a sensor  59  in communication with the low-pressure fluid path defined by the outer tube  56 . The sensor  59  is tuned to detect a change in pressure within the outer tube  56 , and when a change is detected, fluid flow into the system is turned off, as a change in pressure can be an indicator that a leak is present in the system. 
     Continuing to refer to  FIG. 4 , the umbilical  48 . is mated to the first connector  50  and the umbilical  54  is mated to the second connector  52 . The first connector  50  includes O-rings  60  and  62  and is matable with the second connecter  52 , as shown in greater detail in the figures that follow, to provide a fluid-tight connection. The first connector  50  can be locked to the second connector  52  with the assistance of a bayonet-type connection having complimentary protuberances  64  and engagement slots  66 . 
       FIG. 5  is a cross-sectional view of the coaxial connector of  FIG. 4  along line  5 - 5 . In this view, the first connector  50  is shown almost fully mated to the second connector  52 . In this view the inner tube  58  is shown mated to an inner portion  68  of the first connector  50 . The inner portion  68  defines a fluid path  69  leading to an outlet  70  that, when the first and second connectors  50  and  52  are mated, aligns with a fluid inlet  72 -to an injection tube  74 . The O-ring  62  ensures good sealing of the connection. 
     Similarly, the outer tube  56  is shown mated to an outer portion  76  of the first connector  50 . The outer portion defines a fluid path  78  that is in fluid communication with a fluid path  80  defined by the second connector  52 . The fluid path  80  leads to, and is in communication with a fluid path  82  in the umbilical  54 . The O-ring  60  ensures a good seal between the first and second connectors  50  and  52 , respectively. 
       FIG. 6  is a cut-away view of the assembly shown in  FIG. 6 . In this view, the fluid path  69 , outlet  70 , fluid inlet  72 , fluid path  78 , fluid path  80  are all clearly visible. 
       FIG. 7  shows an alternative embodiment of a coaxial arrangement. Shown is a first connector  84  and a second connector  86 . In this embodiment, a male Leur taper fitting  88  is receivable within a female Leur taper receptacle  90  as complimentary locking threads  92  and  94  on the first and second connectors are engaged. When the connectors are fully engaged an O-ring seal  96  prevents leakage for connecting fluid flow paths  98  and  100 . Similarly, an o-ring seal  102  prevents leakage for connecting fluid flow paths  104  and  106 . Exemplary fluid flow through flow paths  104  and  106  is shown by arrows. 
     Yet another connector embodiment is shown in  FIG. 8 . This embodiment provides connections that are not coaxial. As shown, a first connector  108  is mated to an outer tube or catheter shaft  110  with a rigid sleeve  112  and a flexible strain relief element. An fluid injection tube  114  is connected to a high-pressure female connector fitting  116  with a flexible connector tube  118 . Electrical wires  120  that pass through the outer tube  110  terminate at a female pin wire connector  122 . A pull-wire  124  passes through the outer tube  110  and a pull-wire seal fitting  126  to a female pull-wire connector  128 . A pull-wire tension adjuster  130  can also be provided. 
     A second connector  132  includes a male, high-pressure connector  134  that is matable with the fitting  116  to provide a continuous fluid path. A male pull-wire connector  136 , matable with the connector  128 , is axially movable within a portion of the second connector  132  as shown by the double-headed arrow. The connector  136  is secured to a pull-wire  137  that is in turn secured to an actuator (such as element  36  shown in  FIGS. 2 and 3 ). Thus, when the pull-wire  137  is moved axially, the connector  136  moves axially. A bias force can be applied by a bias element  138 , such as a spring, to push the connector  136  to a selected point when axial tension is reduced on the pull-wire. Also shown is a male wire pin connector  140 . 
     A variety of modifications and variations of the present invention are possible in light of the above disclosure. It is therefore understood that, within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described hereinabove.