Patent Publication Number: US-2003236493-A1

Title: Articulating handle for a deflectable catheter and method therefor

Description:
TECHNICAL FIELD  
       [0001] The present invention relates generally to deflectable catheter assemblies. More particularly, it pertains to an articulating handle for a deflectable catheter.  
       BACKGROUND  
       [0002] Increase in the use of stents, leads, and ablation techniques in branch vessels has provided an increased demand in the placement techniques for the devices. For some procedures, it is necessary to initially position a guidewire into a desired part of the lumen of a desired vessel or duct, such as a blood vessel. After the guidewire is positioned within the desired location, a catheter or other tubular device may be positioned over the guidewire and used to convey other medical instruments into the desired blood vessel or duct.  
       [0003] Alternatively, a guiding catheter is used to negotiate the vasculature of a patient. One example of a guiding catheter is described in U.S. Pat. No. 4,898,577 to Badger et al. The Badger guiding catheter includes a single elongate shaft that has a deflectable distal portion controllable by a pull wire. Once the distal portion is at the required deflection or location within the patient, the guidewire or medical instrument is fed through the catheter.  
       [0004] The deflectable catheter is controlled at a proximal end of the catheter by a control handle that operates the pull wire to deflect the catheter, for example, as shown in U.S. Pat. No. 6,171,277. However, with conventional catheter steering mechanisms, it is sometimes difficult to accurately position the catheters in certain body vessels, such as branch veins. For instance, the mechanisms are awkward or require the use of two hands. Other steering mechanisms require pull wires to be wound and unwound around a rotatable cam wheel, causing increased fatigue on the pull wires, and potentially shortening the life of the device.  
       [0005] What is needed is a deflectable catheter that overcomes the shortcomings of previous deflectable catheters. What is further needed is a deflectable catheter that allows for more accurate positioning of the distal end of the deflectable catheter, and that is usable with a single hand.  
       SUMMARY  
       [0006] A catheter assembly includes a handle assembly, and a catheter body coupled with the handle assembly, where the catheter body extends to a deflectable distal end, and the deflectable distal end is controllable by a flexible element. An actuator member is coupled with the flexible element, and movement of the actuator member provides for movement of the flexible element. The actuator has a locked mode and an operational mode, where the actuator and the flexible element are not movable relative to the handle assembly when the actuator is in the locked mode.  
       [0007] Several options for the catheter assembly are as follows. For instance, in one option, the actuator is in a first position in the locked mode and a second position in the operational mode, where the first position is different than the second position. In another option, the flexible element is longitudinally movable by a gearing mechanism coupled with the actuator. In yet another option, the catheter body includes a catheter body lumen, the handle assembly has a handle lumen, and the catheter body lumen is communicatively coupled with the handle lumen. The catheter assembly further includes, in another option, a spring, for instance, a living hinge, is coupled with the actuator, where the spring facilitates movement of the actuator between the locked mode and the operational mode. In yet another option, in the operational mode, the actuator is depressed toward a position within the handle assembly. In yet another option, a trigger is included with the catheter assembly, where movement of the trigger places the actuator member assembly in an operational mode.  
       [0008] In another embodiment, a catheter assembly includes a handle assembly, a catheter body coupled with the handle assembly, and a steering mechanism. The catheter body has a deflectable distal end controllable by a flexible element, where the steering mechanism controls movement of the deflectable distal end. The catheter assembly further includes an indicator associated with the steering mechanism, where the indicator provides affirmative feedback while the steering mechanism is in an operational mode.  
       [0009] Several options are as follows. For instance, in one option, the indicator provides an audible click when the steering mechanism is placed in the operational mode and/or the locked mode. In yet another option, the indicator provides tactile feedback when the steering mechanism is placed in the operational mode and/or the locked mode.  
       [0010] In another embodiment, a method comprises manipulating a catheter assembly, the catheter assembly including a handle assembly, a catheter body controllable by a flexible element coupled with the handle assembly. An actuator member is coupled with the flexible element, where movement of the actuator member provides for movement of the flexible element, and the actuator has a locked mode and an operational mode. The actuator and the flexible element are not movable relative to the handle assembly when the actuator is in the locked mode. The method further includes moving the actuator and unlocking the actuator, and placing the actuator in an operational mode. In addition, the method includes steering the catheter assembly including moving the actuator and deflecting the distal end.  
       [0011] Several options for the method are as follows. For instance, in one option, the method further includes releasing the actuator and locking movement of the flexible element relative to the handle assembly. In another option, the method further includes providing feedback to the user when the actuator is placed in the operational mode and/or the locked mode. In yet another option, placing the actuator in the locked mode includes enmeshing a gear coupled with the actuator with a static component, for example a paw as discussed above. Optionally, moving the actuator includes depressing the actuator within the handle assembly.  
       [0012] The deflectable catheter allows for single handed precise movement of the distal tip, and allows for locking a position in place easily. The lock further assists in preventing inadvertent movement of the distal tip, for example, during an ablation procedure. Furthermore, with the above-described design, the distal end can be easily configured to have different radius of curvature by varying the stroke length. Another option is to vary the input/output of the actuator by modifying the gear ratio. A further benefit of the device is the feedback provided when the lock is released, for example, the audible click. This affirmatively informs the physician when the steering mechanism is placed in the operational mode and/or the locked mode.  
       [0013] These and other embodiments, aspects, advantages, and features of the present invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art by reference to the following description of the invention and referenced drawings or by practice of the invention. The aspects, advantages, and features of the invention are realized and attained by means of the instrumentalities, procedures, and combinations particularly pointed out in the appended claims and their equivalents.  
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0014]FIG. 1A is a perspective view illustrating a deflectable catheter assembly constructed in accordance with one embodiment.  
     [0015]FIG. 1B is a perspective view illustrating a deflectable catheter assembly constructed in accordance with one embodiment.  
     [0016]FIG. 2 is a perspective view illustrating a deflectable catheter body constructed in accordance with one embodiment.  
     [0017]FIG. 3 is a perspective view illustrating a distal portion of the deflectable catheter body constructed in accordance with one embodiment.  
     [0018]FIG. 4 is a perspective view illustrating a handle assembly constructed in accordance with one embodiment.  
     [0019]FIG. 5A is an exploded view illustrating a portion of a catheter assembly constructed in accordance with one embodiment.  
     [0020]FIG. 5B is an exploded view illustrating a portion of a catheter assembly constructed in accordance with another embodiment.  
     [0021]FIG. 6 is a side view illustrating a portion of the catheter assembly in a locked mode constructed in accordance with one embodiment.  
     [0022]FIG. 7 is a side view illustrating a portion of the catheter assembly in an operational mode constructed in accordance with one embodiment.  
    
    
     DESCRIPTION OF THE EMBODIMENTS  
     [0023] In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the present invention. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents.  
     [0024]FIGS. 1A and 1B illustrate a deflectable catheter assembly  100 , where FIG. 1A illustrates the deflectable catheter assembly  100  in an articulated position, and FIG. 1B illustrates the deflectable catheter assembly  100  in an unarticulated position. The deflectable catheter assembly  100  includes a deflectable catheter body  110  and a handle assembly  150  that houses steering mechanisms for deflection of the catheter body  110 . The handle assembly  150 , as described in greater detail below, allows for the deflection of a distal end of the catheter body  110 . In one option, the pull wire  120  (FIG. 2) is connected to an actuator that is slid or rotated to apply tension to the pull wire  120  (FIG. 2). As tension is applied to the pull wire  120  (FIG. 2), the pull wire anchor at the distal end of the catheter body  110  is pulled which causes the distal portion of the catheter body  110  to curve in a predetermined direction or directions.  
     [0025] With reference to FIG. 2, the catheter body  110  comprises, in one option, an elongate tubular construction that is flexible yet substantially non-compressible along its length. The deflectable catheter body  110  extends from a proximal end  102  to a distal end  104 , where the distal end  104  is disposed within a patient. At the proximal end  102  is a proximal tip  103 , and at the distal end  104  is a distal tip  105 . At the proximal end  102 , the physician controls the deflection of the deflectable catheter body  110  with the handle assembly  150  (FIGS. 1A and 1B) and a pull wire  120  (FIG. 3), as further described below. The distal end  104  is deflected to traverse various branch vessels with the catheter assembly  100  (FIG. 1).  
     [0026]FIG. 3 illustrates a partial cut-away view of FIG. 2, including the distal end  104  of the catheter body  110 . The catheter body  110  includes a pull wire anchor  121  that is secured to the catheter body  110 . The pull wire  120  is mechanically secured to the pull wire anchor  121 , for example, by welding the pull wire  120  to the pull wire anchor  121 . It should be noted that the pull wire can be secured to the distal end  104  of the catheter body  110  in other manners. The pull wire anchor  121 , in one option, comprises a marker band  119  that is viewable, for example, under fluoroscopy. In one option, the catheter body  110  includes a stiffening member embedded therein, such as a braided stainless steel member  111 . The stiffening member facilitates rotation of the distal end  104  from the proximal end  102 , and also assists in preventing the catheter body  110  from collapsing.  
     [0027] The handle assembly  150  is shown in greater detail in FIGS. 4, 5A, and  5 B. The handle assembly  150  includes a handle housing  152  is designed to easily and comfortably fit into a practitioners hand, and to be easily manipulated with single hand use. In one option, the handle housing  152  are formed of a first portion  154  and a second portion  156  that are coupled together, for example, by one or more threaded fasteners. Other devices and/or methods for coupling the first and second portions  154 ,  156  of the handle housing  152  are suitable as well, such as, but not limited to, adhesive, welding, snap-fit, etc.  
     [0028] The handle housing  152  includes a handle lumen  158  therein. The handle lumen  158  is aligned with the delivery lumen of the catheter body  110  (FIG. 2), and the handle lumen  158  extends from a first end  160  to a second end  162  of the housing. A medical instrument, such as, but not limited to, a guidewire, a lead, an ablating device, etc., is disposed through the second end  162  of the housing  152  and through the delivery lumen of the catheter body  110  (FIG. 2). In one option, a valve  130  is coupled with the delivery lumen of the catheter body  110  (FIG. 2). The valve  130  provides further prevention of inadvertent fluid leakage from the delivery lumen. In another option, a side port  132  is coupled with the valve  130 , which allows for the valve  130  to be flushed with fluids. The side port  132  is disposed through a portion of the handle assembly  150 , for example, through an opening  134 , allowing access to the side port  132  by a physician or medical technician. It should be noted that the valve  130  and/or the side port  132  can be combined with any of the above or below discussed embodiments.  
     [0029] The handle assembly  150  includes therein the actuator assembly  170  that moves the pull wire  120  (FIG. 2), and deflects the distal end  104  (FIG. 2) of the catheter body  110  (FIG. 2). Referring to FIG. 5A, the actuator assembly  170  includes an actuator  172  disposed through a slot  173  of the handle housing  152 . The actuator  172  is manipulatable by an operator to deflect the distal end  104 . In one option, the actuator  172  includes a wheel member  174  that is easily manipulated by the thumb in a rolling motion. The rotational input from the thumb is transferred into linear movement to provide the linear stroke for the pullwire on the proximal end, as further described below.  
     [0030] The following is one example of how to construct the steering assembly. It should be noted that several variations exist, including more simplified gearing configurations. In one option, the actuator  172  is coupled with a first axle  175  that rotates about a first actuator axis  176 . Also coupled with the first axle  175  is a first gear  178  that meshes with a second gear  180 . The second gear  180  is coupled with a second axle  181  that rotates about a second axis  182 .  
     [0031] A third gear  184 , in one option, is disposed on the opposite side of the actuator  172  as the first gear  178 . The third gear  184  is fixed with the first axle  175  and is adapted to mesh with a static component, such as locking paw  186 , when the actuator assembly  170  has been placed in a locked mode. The locking paw  186  is affixed to the handle portion, for example, with threaded fasteners. In one option, the locking paw  186  includes, for example, teeth integrally formed within the handle housing. A biasing member  202 , such as, but not limited to, a spring, a living hinge, a spring steel member, biases the third gear  184  into meshing with the locking paw  186  when no force is placed on the actuator  172 . It should be noted that one or more biasing members  202  can be used to bias the actuator  172  into a locked position.  
     [0032] The locking paw  186  mechanically prevents the actuator  172  from moving until it is moved out of the locked mode. When the actuator assembly  170  is placed in the locked mode, as shown in FIG. 6, the actuator  172  is mechanically locked from moving, which also locks the pull wire from moving. This is particularly advantageous over conventional designs, or designs that prevent movement by friction, since the physician can be confident that the deflection of the distal end will not be inadvertently modified. Furthermore, when the distal end is in a highly articulated position, the distal end will not succumb to change when the physician releases the steering mechanism, for example, to introduce other instruments through the catheter assembly.  
     [0033]FIG. 5B illustrates another example of the gearing mechanism for the catheter assembly. The actuator  172  is coupled with a series of gears  138  that, in one option, are assembled in a linear fashion. The series of gears  138  are each coupled with an axle  142 , about which each gear  140  rotates. In one option, the axle  142  includes a projection  144 , such as a post, that extends from an inner surface  146  of the handle housing  152 . Alternatively, or in combination, the axle  142  is disposed through or made integral with the gear  140 , and the axle  142  is disposed within a recess formed within the handle housing  152 . The axle  142  can be coupled directly or indirectly with the handle housing  152 . The series of gears  138  cooperatively operate as is shown in FIG. 5B, where a first gear  146  is coupled with the actuator  172 . Rotation of the actuator  172  causes rotation of the series of gears  138 , and linear movement of the rack  194 , as further discussed below. Locking and unlocking of the series of gears  138  can be achieved using the various embodiments discussed above and below, and shown in the Figures.  
     [0034] When the actuator assembly  170  is affirmatively placed in an operational mode, as shown in FIG. 7, the third gear  184 , or the series of gears  138 , is free to rotate, allowing the actuator  172  to freely rotate. In one option, to place the actuator assembly  170  in an operational mode, the actuator  172  is depressed to a position at least partially within the handle housing  152 . As the actuator  172  is depressed, the user overcomes the bias from the biasing member, and the third gear  184  disengages from the locking paw  186 . In another option, a trigger  173  (FIG. 5B) that is remote from the actuator  172  is used to place the actuator assembly  170  in operational mode. In one option, as the actuator assembly  170  is placed in operational mode, an audible click can be heard, thereby notifying the physician that the assembly is affirmatively in the operational mode. Other options for indicating to the physician that the status of operation has changed are possible as well. For example, a tactile click can be felt on the actuator  172 , or a visual indicator can be provided, as further discussed below.  
     [0035] During operation, when the actuator assembly  170  is in the operation mode, the actuator  172  drives one or more gears  190 , including a driving gear  192 . The driving gear  192  drives a rack  194  that is coupled with the pull wire  120  (FIGS. 2 and 6). As the actuator  172  is moved, for example, rotated, the rack  194  is moved linearly and thereby pulls the pull wire  120 . The linear movement of the rack  194  in combination with the pull wire  120  assists in preventing unnecessary fatigue being placed on the pull wire  120 , for example by wrapping and unwrapping the pull wire  120  around a rotating member.  
     [0036] As the pull wire  120  is moved, this pulls on the pull wire anchor, and the distal end of the catheter body is deflected into position as desired by the physician. In one option, an indicator is associated with the movement or deflection of the catheter body, such that feedback is provided while the body is being moved. When in place or in a proper position, the physician releases the actuator  172 , allowing the actuator assembly  170  to be locked in place, and further movement of the distal end is affirmatively prevented. In one option, as the physician releases the actuator  172 , an audible click can be heard. For example, the meshing of the gears can be configured to cause an audible click. Other options for indicating to the physician that the status of operation has changed are possible as well. For example, a tactile click can be felt on the actuator  172 , or a visual indicator can be provided when the actuator  172  is placed in the locked mode. In another option, the tactile click is caused by friction or rubbing of two or more components. The notice to the physician, in another option, involves an audible sound, or a tactile or visual indicator while the actuator  172  is being moved to manipulate the flexible element. For instance, in one option, while the actuator  172  is moved by the physician, a projection or finger would mesh with indentations or projections on the actuator  172 , allowing the physician to feel or hear a clicking sound as the actuator  172  is rotated or moved. This can be done exclusive to the audible click or tactile click or visual indicator, or it can enhance these features. It should be noted that other indicators can be incorporated herein, and/or incorporated with the various embodiments discussed/shown above and below.  
     [0037] In another embodiment, a method comprises manipulating a catheter assembly, the catheter assembly including a handle assembly, a catheter body controllable by a flexible element coupled with the handle assembly. An actuator member is coupled with the flexible element, where movement of the actuator member provides for movement of the flexible element, and the actuator has a locked mode and an operational mode. The actuator and the flexible element are not movable relative to the handle assembly when the actuator is in the locked mode. The method further includes moving the actuator and unlocking the actuator, and placing the actuator in an operational mode. In addition, the method includes steering the catheter assembly including moving the actuator and deflecting the distal end.  
     [0038] Several options for the method are as follows. For instance, in one option, the method further includes releasing the actuator and locking movement of the flexible element relative to the handle assembly. In another option, the method further includes providing feedback to the user when the actuator is placed in the operational mode and/or the locked mode. In yet another option, placing the actuator in the locked mode includes enmeshing a gear coupled with the actuator with a static component. Optionally, moving the actuator includes depressing the actuator within the handle assembly.  
     [0039] Advantageously, the above-described deflectable catheter allows for increased control of the distal deflectable catheter end. The locking mechanism provides for accurate locking of the deflectable end in a certain position, allowing the physician increased control during the placement of the catheter within a patient. Furthermore, the indicator informs the physician when the deflectable catheter assembly has been placed in a locked and/or operational mode.  
     [0040] The deflectable catheter allows for single handed precise movement of the distal tip, and allows for locking a position in place easily. The lock further assists in preventing inadvertent movement of the distal tip, for example, during an ablation procedure. Furthermore, with the above-described design, the distal end can be easily configured to have different radius of curvature by varying the stroke length. Another option is to vary the input/output of the actuator by modifying the gear ratio. A further benefit of the device is the feedback provided when the lock is released, for example, the audible click. This affirmatively informs the physician when the steering mechanism is placed in the operational mode and/or the locked mode.  
     [0041] It is to be understood that the above description is intended to be illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reading and understanding the above description. It should be noted that embodiments discussed in different portions of the description or referred to in different drawings can be combined to form additional embodiments of the present invention. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.