Abstract:
The present invention relates generally to the field of embolic protection and, more particularly, to systems for locking a shaft relative to a hub assembly. In addition, a method for securing a shaft relative to a hub assembly is disclosed.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to the field of embolic protection. More particularly, the present invention pertains to systems for locking a filter shaft relative to a delivery or retrieval sheath in an embolic protection device.  
         BACKGROUND OF THE INVENTION  
         [0002]    Heart disease is a major problem in the United States and throughout the world.  
           [0003]    Conditions such as atherosclerosis result in blood vessels becoming blocked or narrowed. This blockage can result in lack of oxygenation of the heart, which has significant consequences since the heart muscle must be well oxygenated in order to maintain its blood pumping action.  
           [0004]    Occluded, stenotic, or narrowed blood vessels may be treated with a number of relatively non-invasive medical procedures including percutaneous transluminal angioplasty (PTA), percutaneous transluminal coronary angioplasty (PTCA), and atherectomy. Angioplasty techniques typically involve the use of a balloon catheter. The balloon catheter is advanced over a guidewire such that the balloon is positioned within a stenotic lesion. The balloon is then inflated and the restriction of the vessel is opened.  
           [0005]    During an atherectomy procedure, the stenotic lesion may be mechanically cut away from the blood vessel wall using an atherectomy catheter. During angioplasty and atherectomy procedures, embolic debris can be separated from the wall of the blood vessel. If this debris enters the circulatory system, it could block other vascular regions including the neural and pulmonary vasculature, both of which are highly undesirable. During angioplasty procedures, stenotic debris may also break loose due to manipulation of the blood vessel. Because of this debris, a number of devices, termed embolic protection devices, have been developed to filter out this debris.  
         SUMMARY OF THE INVENTION  
         [0006]    The present invention pertains to embolic protection devices. More particularly, the present invention includes a system for locking a shaft relative to a delivery or retrieval sheath. The sheath may comprise a proximal end, a distal end, and a lumen extending therethrough. The shaft may have an embolic protection filter coupled to its distal end. The shaft may be adapted to be disposed within the lumen of the sheath.  
           [0007]    An assembly may be coupled to the sheath and a splitter may be coupled to the assembly. The splitter may include a tube having an inner lumen adapted to slidably receive the sheath, and a shaft coupling portion to secure the shaft relative to the assembly with a locking member. Multiple differing embodiment of the splitters are disclosed. For example, the shaft coupling portion may include a wire lumen. Alternatively, the shaft coupling portion may include a slot. The shaft may be secured relative to the assembly by a collet, a collar, a slot, a pinchable tube, etc. The splitter may further comprise a physical stop or a luer adapter.  
           [0008]    Alternate embodiments of the present invention may also include a sliding handle or the inclusion of a securement shaft. These embodiments may help to address the issue of catheter bowing, which may also interfere with movement of the shaft relative to the assembly. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is a partial cross-sectional view of an embolic protection assembly including a system for locking an elongate shaft relative to a hub assembly;  
         [0010]    [0010]FIG. 2 is a perspective view of a splitter for use with the shaft and sheath lock system;  
         [0011]    [0011]FIG. 3 is a cross-sectional view through line  3 - 3  of the splitter shown in FIG. 2;  
         [0012]    [0012]FIG. 4 is a perspective view of an alternate splitter for use with the shaft and sheath lock system;  
         [0013]    [0013]FIG. 5 is a cross-sectional view through line  5 - 5  of the splitter shown in FIG. 4;  
         [0014]    [0014]FIG. 6 is a perspective view of a second alternate splitter for use with the shaft and sheath lock system;  
         [0015]    [0015]FIG. 7 is a cross-sectional view through line  7 - 7  of the splitter shown in FIG. 6;  
         [0016]    [0016]FIG. 8 is a perspective view of a third alternate splitter for use with the shaft and sheath lock system;  
         [0017]    [0017]FIG. 9 is a cross-sectional view through line  9 - 9  of the splitter shown in FIG. 8;  
         [0018]    [0018]FIG. 10 is a perspective view of a fourth alternate splitter for use with the shaft and sheath lock system;  
         [0019]    [0019]FIG. 11 is a cross-sectional view through line  11 - 11  of the splitter shown in FIG. 10;  
         [0020]    [0020]FIG. 12 is a perspective view of a fifth alternative splitter having a physical stop;  
         [0021]    [0021]FIG. 13 is a perspective view of a sixth alternative splitter having a luer adapter;  
         [0022]    [0022]FIG. 14 is a perspective view of the splitter shown in FIG. 13 further comprising a passive valve coupled to the luer adapter;  
         [0023]    [0023]FIG. 15 is a plan view of a splitter coupled to a y-adapter according to an embodiment of the invention;  
         [0024]    [0024]FIG. 16 is a perspective view of a locking member for securing a wire to a hub;  
         [0025]    [0025]FIG. 17 is a perspective view of an alternate locking member for securing a wire to a hub;  
         [0026]    [0026]FIG. 18 is a side view of an alternate embolic protection assembly; and  
         [0027]    [0027]FIG. 19 is a side view of a second alternate embolic protection assembly. 
     
    
     DETAILED DESCRIPTION  
       [0028]    The following description should be read with reference to the drawings wherein like reference numerals indicate like elements throughout the several views. The detailed description and drawings illustrate example embodiments of the claimed invention.  
         [0029]    When delivering or retrieving an embolic protection filter, it may be important to the secure the position of the filter relative to a delivery or retrieval sheath. This may allow a clinician to accurately deliver or retrieve the filter and minimize unwanted or unplanned movement. FIG. 1 is a partial cross-sectional view of an embolic protection assembly  10  including a shaft and sheath lock system  11  for locking an elongate shaft or wire  12  relative to a sheath  14 . Shaft and sheath lock system  11  may include a splitter  16  that may separately couple to both shaft  12  and sheath  14  to, for example, secure shaft  12  while allowing movement of sheath  14 . The inclusion of splitter  16  may allow the clinician to easily and precisely deliver or retrieve an embolic protection filter  18 .  
         [0030]    Assembly  10  may include a hub and/or guide catheter assembly including, for example, a guide catheter  13  with a proximal hub  15  having a y-adaptor  17  attached thereto. The configurations of guide catheter  13 , hub  15  and y-adaptor  17  can be similar to similar devices known in the art. Guide catheter  13 , hub  15 , and y-adaptor  17  may all be configured to receive sheath  14  within an inner lumen.  
         [0031]    Shaft  12  may comprise a guidewire having a proximal end  20  and a distal end  22 . Shaft  12  may be comprised of metals including, but not limited to stainless steel, nickel alloys, and nickel-titanium alloys. Alternatively, shaft  12  may be comprised of one or more polymers or a metal-polymer composite. Embolic protection filter  18  may be coupled to shaft  12  proximate distal end  22 .  
         [0032]    Filter  18  may be comprised of a polyurethane sheet and include at least one opening that may be, for example, formed by known laser techniques. The holes or openings are sized to allow blood flow therethrough but restrict flow of debris or emboli floating in the body lumen or cavity. Filter  18  may be generally cone-shaped, and have a proximal and a distal end. The distal end may be a narrow, “V”-shaped end and can be fixedly secured or formed to shaft  12 . The proximal end has a relatively wide opening.  
         [0033]    Filter  18  operates between a closed collapsed profile and an open radially-expanded deployed profile for collecting debris in a body lumen. Filter  18  may include a collapsible proximally-tapered frame having a mouth and a plurality of longitudinally-extending ribs. In an expanded profile, the mouth is opened and the ribs extend radially outwardly to support the mouth. A number of differing configurations of filter  18  may be substituted without departing from the spirit of the invention.  
         [0034]    Sheath  14  may be comprised of one or more metals (such as those listed above), one or more polymers, or a metal-polymer composite. Sheath  14  may be generally tubular and include a proximal end  24 , a distal end  26 , and a lumen  28  extending through at least a portion thereof that is adapted and configured to slidably receive shaft  12 . For example, lumen  28  may extend through a portion of sheath  14  and exit sheath  14  through a port  30  located near distal end  26  so that sheath  14  may be used in combination with shaft  12  as a single-operator-exchange catheter. Alternatively, lumen  28  could extend throughout the length of sheath  14 .  
         [0035]    Splitter  16  may be constructed of any of the material listed above and may be manufactured by a number of techniques including injection molding and extrusion. Splitter  16  may comprise a tube  32  that includes an inner lumen  34  (best seen in FIG. 2) adapted to slidably receive sheath  14  and a shaft coupling portion  36 . According to this embodiment, shaft  12  can be secured, while sheath  14  remains slidable within lumen  34 .  
         [0036]    Splitter  16  may be used to secure the position of shaft  12  relative to y-adaptor  17 . To do so, shaft  12  may be secured between two surfaces. For example, y-adaptor  17  may have a collet  38  disposed at one end. Collet  38  is essentially the same in form and function as typical known collets. When shaft  12  is disposed at coupling portion  36 , a collar  40  may be tightened onto collet  38 , causing collet  38  deform inwardly toward splitter  16 . As collet  38  becomes more closely associated with splitter  16  (i.e., tightened onto splitter  16 ), shaft  12  may be secured between collet  38  and coupling portion  36 .  
         [0037]    A handle  42  may be coupled to sheath  14  near proximal end  24  thereof. Handle  42  may include a button  44  that may be configured so that actuation of button  44  may result in movement of sheath  14 . For example, button  44  may be slidable along the longitudinal axis of handle  42  such that movement button  44  in a distal direction results in substantially equivalent movement of sheath  14  in the distal direction. According to this embodiment, handle  42  may be used to control the position of sheath  14 . Moreover, when handle  42  is used in combination with splitter  16  such that shaft  12  may be secured relative to y-adaptor  17 , handle  42  may be used to easily and precisely deliver or retrieve filter  18 .  
         [0038]    [0038]FIG. 2 is a perspective view of splitter  16 . As mentioned above, splitter  16  may include tube  32  having inner lumen  34  adapted and configured to slidably receive sheath  14 . Variations between different splitters appropriate for multiple embodiments may include variations of shaft coupling portion  36  as depicted in this and a number of the following figures. For example, shaft coupling portion  36  may include a lumen opening  46  to a shaft lumen  48  that extends through at least a portion of splitter  16 . According to this embodiment, shaft  12  may be configured to pass through opening  46  and into shaft lumen  48 .  
         [0039]    Securing shaft  12  relative to y-adaptor  17  when using splitter  16  may occur in a number of different ways. It is believed that a portion of shaft  12  would be disposed at opening  46  that would be sufficient to allow shaft  12  to be secured between splitter  16  and collet  38  (as shown in FIG. 1). According to this embodiment, shaft  12  would pass through opening  46  (for example by back loading shaft  12  into opening  46 ) and into lumen  48 . Collar  40  may then be actuated to secure shaft  12  between collet  38  and splitter  16 . Alternatively, lumen  48  may be collapsed on shaft  12  due to pressure exerted by collet  38 . According to this embodiment, collet  38  can collapse lumen  48  by actuating collar  40 .  
         [0040]    [0040]FIG. 3 is a cross-sectional view through line  3 - 3  of splitter  16 . Shaft lumen  48  may be adapted to slidably receive shaft  12 . In addition, shaft lumen  48  may include structural support for inner lumen  34  in the form of a support tube  50  (e.g., a stainless steel tube, etc.) disposed proximate at least a portion of inner lumen  34 . Manufacturing of splitter  16  with support tube  50  (and other splitters and support tubes described herein) may include providing support tube  50  and overmolding or coextruding at least a portion of splitter  16  therewith. Support tube  50  may add sufficient structural support so as to prevent inner lumen  34  from collapsing on sheath  14  when securing shaft  12 . Alternatively, splitter  16  may be manufactured to include a web region  51  between inner lumen  34  and shaft lumen  48  that is sufficiently large to provide any necessary structural support.  
         [0041]    [0041]FIG. 4 is a perspective view of an alternate splitter  116 . Splitter  116  may include inner lumen  134  and shaft coupling portion  136  that includes a slot  152  extending along the length of splitter  116 . According to this embodiment, shaft  12  may be disposed within slot  152  and could be front loaded or be back loaded. Slot  152  may be shaped so that shaft  12  may be coupled to splitter  116  by snapping or otherwise disposing shaft  12  into slot  152 . According to this embodiment, shaft  12  may be secured relative to y-adaptor  17  by snapping shaft  12  into slot  152  and tightening collet  38 .  
         [0042]    As an alternative to or in addition to what is described above, shaft  12  may be also secured by collet  38  as described above. For example, shaft  12  may be disposed within slot  152  and be secured between slot  152  and collet  38  by actuating collar  40  to tighten collet  38 .  
         [0043]    A cross-sectional view through line  5 - 5  of splitter  116  is depicted in FIG. 5. Similar to what is described above, splitter  116  may include structural support as described above. For example, splitter  116  may further comprise support tube  150  disposed proximate at least a portion of inner lumen  134 .  
         [0044]    [0044]FIG. 6 is a perspective view of a second alternate splitter  216 . Splitter  216  includes inner lumen  234  and is essentially similar to splitter  116  except that shaft coupling portion  236  includes an alternate slot  252  having a slightly different shape than slot  152 . The shape of slot  252  may simplify the process of securing shaft  12  or may provide other advantages. For example, slot  252  may be used to secure shaft  12  to splitter  216  by snapping or otherwise disposing shaft  12  into slot  252  (and, in some embodiments, tightening collet  38 ) in a manner similar to what is disclosed above. Alternatively, shaft  12  may be secured between splitter  216  and collet  38 , for example by actuating collar  40  so as to tighten collet  38 .  
         [0045]    A cross-sectional view through line  7 - 7  of splitter  216  is depicted in FIG. 7. Similar to what is described above, splitter  216  may include structural support. For example, splitter  216  may further comprise a support tube  250  disposed proximate at least a portion of inner lumen  234 .  
         [0046]    [0046]FIG. 8 is a perspective view of a third alternate splitter  316 . Splitter  316  includes inner lumen  334  and is similar to the previously disclosed wire locks except that shaft coupling portion  336  includes a plurality of raised ribs  354  and a plurality of slots  352  between ribs  354 . Slots  352  may be adapted to receive shaft  12  in ways analogous to what is described above. For example, shaft  12  may be disposed within slots  352 .  
         [0047]    A cross-sectional view through line  9 - 9  of splitter  316  is depicted in FIG. 9. Similar to what is described above, splitter  316  may include structural support. For example, splitter  316  may further comprise support tube  350  disposed proximate at least a portion of inner lumen  334 .  
         [0048]    [0048]FIG. 10 is an enlarged view of a fourth alternate splitter  416 . Splitter  416  includes inner lumen  434  and is essentially similar to splitter  316  except that shaft coupling portion  436  includes raised ribs  454  that are larger (i.e., define deeper slots  452  between ribs  454 ) than ribs  354 . Slots  452  may be adapted to receive and shaft  12  in ways analogous to what is described above.  
         [0049]    A cross-sectional view through line  11 - 11  of splitter  416  is depicted in FIG. 11. Similar to what is described above, splitter  416  may include structural support. For example, splitter  416  may further comprise support tube  450  disposed proximate at least a portion of inner lumen  434 .  
         [0050]    [0050]FIG. 12 is a perspective view of a fifth alternative splitter  516 . Splitter  516  may include inner lumen  534 , shaft coupling portion  536 , opening  546 , and shaft lumen  548  that may be substantially similar to any of those listed above. In addition, shaft coupling portion  536  may further comprise a physical stop  556 . Physical stop  556  may make it easier for a user to determine how far splitter  516  needs to be advanced within collet  38  or prevent splitter  516  from advancing too deeply into collet  38 .  
         [0051]    As shown in FIG. 12, stop  556  is shaped as a full circumference member or enlargement coupled to splitter  516 . It can be appreciated that stop  556  could be essentially any shape or configuration that is appropriate for stopping splitter  516  from advancing too deeply into collet  38 . For example, stop  556  may comprise a single tab or notch, a partial circular member (similar to what is shown in FIG. 12 except not covering the full circumference of splitter  556 ), etc.  
         [0052]    [0052]FIG. 13 is a perspective view of a sixth alternative splitter  616 . Splitter  616  may include shaft coupling portion  636  having inner lumen  634 , a plurality of ribs  654 , and a luer adapter  658 . Although FIG. 13 depicts shaft coupling portion  636  as having ribs  654 , it should be noted that any of the shaft coupling portions discussed throughout this detailed description may be substituted without departing from the spirit of the invention. Luer adapter  658  may allow other objects to be coupled to splitter  616 . For example, FIG. 14 depicts a passive valve  660  coupled to splitter  616 . Passive valve  660  may prevent blood from being lost through sheath  14  (or inner lumen  634 ) during a medical procedure.  
         [0053]    [0053]FIG. 15 is an enlarged view of a seventh alternate splitter  716 . Splitter  716  may be attached to hub  15  of guide catheter  13  in place of y-adapter  17  (please refer to FIG. 1). According to this embodiment, splitter  716  may include a dual touhy y-adapter  738  having a main branch  764  having a main lumen  766 . In addition, y-adapter  738  may include and a side branch  768  having a side lumen  770 .  
         [0054]    Splitter  716  may include any of the features attributed to similar objects above and may comprise tube  732 , inner lumen  734 , and shaft coupling portion  736 . Inner lumen  734  may be in fluid communication with main lumen  766 . Shaft coupling portion  736  may include a wire guide  772  that is in fluid communication with side lumen  770 . According to this embodiment, shaft  12  may be disposed within wire guide  772  and may be branched away from splitter  716  and into side lumen  770 .  
         [0055]    Shaft  12  may then be secured by using locking member  740  in a manner similar to what is described above. For example, locking member  740  may comprise a collet assembly that includes a collet (similar to collet  38 ) that clamps down upon shaft  12  when the locking member  740  (e.g., a collar similar to collar  40 ) is actuated. A person of ordinary skill in the art would be familiar with uses of a collet that may be appropriate for multiple embodiments.  
         [0056]    [0056]FIG. 16 is a perspective view of an alternate locking member  840 . Locking member  840  may be used in place of y-adaptor  17  or in conjunction with (i.e., attached at one end of) y-adaptor  17 , y-adaptor  738 , etc. Locking member  840  may comprise a hinged arm  874  having a pinching portion  876  rotatable about an axis A. Shaft  12  may pass through a collapsible wire tube  878  such that when hinged arm  874  is clamped, pinching portion  876  applies a force onto tube  878  sufficient to collapse tube  878  and secure shaft  12  therein. Thus, tube  878  may be comprised of a compressible or collapsible material such as silicone. Shaft  12  can enter wire tube  878  by passing through a wire conduit  879  coupled to collapsible tube  878 . Likewise, sheath  14  may be disposed within a sheath conduit  881 . While shaft  12  is secured, sheath  14  may moved independently of shaft  12 . Hinged arm  874  may be unclamped to relieve the force applied onto wire tube  878  by pinching portion  876 . Locking member  840  may be manufactured by a number of techniques including injection molding.  
         [0057]    [0057]FIG. 17 is a perspective view of a second alternate locking member  940 . This embodiment may be used in conjunction with any of the shaft coupling portions described above and may be incorporated into a distal end of handle  42  (please see FIG. 1). Locking member  940  includes a splitter  916  that separates sheath  14  and shaft  12  by allowing sheath to pass into a sheath conduit  973  and shaft  12  to pass into a wire guide  972 . Wire guide  972  is adapted to slidably receive to shaft  12  and a fitting  980  that may be secured to wire guide  972 . A pinching button  982  may be coupled to fitting  980  such that pressing button  982  may dispose fitting  980  onto wire guide  972 , securing wire  12  in position. Locking member  940  may be manufactured by a number of techniques including injection molding.  
         [0058]    [0058]FIG. 18 is a side view of an alternate embolic protection assembly  1010  including a sliding handle  1084 . Sheath  14  may be allowed to freely move within inner lumen  34  and be used with a collet  38  and collar  40  as described previously in FIG. 1 (or other analogous splitters or analogous objects described herein). Handle  1084  (an alternate to handle  42 ) may include means for actuating sheath  14 , for example a button  1086  or equivalents thereof. By including a splitter in accordance with any of the above-described embodiments, button  1086  may be used to shift the position of sheath  14  relative to shaft  12 .  
         [0059]    Because handle  1086  may be disposed a distance away from collar  40 , actuation of sheath  14  may result in bowing between handle  1084  and collar  40 . Bowing may interfere with the ability of a user to shift shaft  12  relative to sheath  14 . To address this issue, handle  1084  may be slidable along the length of sheath  14 .  
         [0060]    Handle  1084  may further comprise a touhy-borst fitting  1088  that may be used to secure handle  1084  to sheath  14 . An intermediate shaft  1089  may extend between handle  1084  and fitting  1088  and be integrally coupled to button  1086 . According to this embodiment, handle  1084  may be slid to a position proximate collar  40  when fitting  1088  is loosened. When handle  1084  is moved to a desirable position (e.g., proximate collar  40 ) fitting  1088  may be tightened to secure handle  1084  to sheath  14 . Alternatively, fitting  1088  may comprise a collet or other element appropriate for securing handle  1084  relative to sheath  14 .  
         [0061]    Once handle  1084  is secured relative to sheath  14 , sheath  14  may be manipulated relative to shaft  12  by actuating button  1086 . In order to accommodate movement of sheath  14  relative to shaft  12 , intermediate shaft  1089  may be moveable within a portion of handle  1084 . For example, when button  1086  is actuated in the proximal direction, intermediate shaft  1089  and fitting  1088  move proximally, increasing the space between handle  1084  and fitting  1088 . Because sheath  14  is secured by fitting  1088 , proximal movement of fitting  1088  results in proximal movement of sheath  14 . Thus, having intermediate shaft  1089  disposed movably within a portion of handle  1084  allows handle to function in order to both alter the position of sheath  14  and be slidable along sheath  14 .  
         [0062]    [0062]FIG. 19 is a side view of a second alternate embolic protection assembly  1110  that includes a securement shaft  1190 . Securement shaft  1190  is an alternative way to address catheter bowing. Securement shaft  1190  can be, for example, located between handle  1184  collar  40 . Securement shaft  1190  may extend distally beyond collar  40  but should not go beyond the aortic arch when used for a medical procedure. For example, securement shaft  1190  may be about twelve to fourteen inches in length. Securment shaft  1190  may also have an outside diameter small enough to assure that it may fit into a guide catheter. Securement shaft  1190  may provide physical support in order to prevent catheter bowing. Securement shaft  1190  may also address the issue of inadvertent movement of handle  1184  while retrieving filter  18 .  
         [0063]    Securement shaft  1190  may be manufactured by extrusion. Moreover, securment shaft  1190  may further comprise an outer wire braiding that may help prevent securement shaft  1190  from collapsing due to the clamping force of a fitting (e.g., a touhy-borst fitting). In addition, it should be noted that embodiments of splitters, locking members, hubs, handles, and other elements disclosed above may also be used in combination with one another. Alternatively, features of any of the locking members disclosed above may be incorporated into handle  1184 .  
         [0064]    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.