Abstract:
A device includes a protection sleeve ( 10 ) and a retractable sheath ( 14 ) operatively connected to the protection sleeve ( 10 ), and a catheter ( 16 ) that passes through a main lumen ( 26 ) of the sleeve ( 10 ). The catheter ( 16 ) includes a heart valve treatment device arranged to pass into a lumen of the catheter ( 16 ).

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention generally relates to capturing embolic or other materials, such as during cardiovascular surgery, and particularly to a percutaneous protection sleeve, which can either serve as a guidance sleeve or slide over a catheter. 
       BACKGROUND OF THE INVENTION 
       [0002]    In valve repair or replacement surgery, manipulation of calcified valves may result in dislodgment of calcified material, particles of tissue and other debris, all referred to herein as embolic debris or simply emboli. The embolic debris can migrate through the circulatory system and cause vessel occlusion, blood clots and cerebrovascular accidents, or strokes. A need therefore exists for safely containing embolic debris during cardiovascular surgery. 
         [0003]    One method used in the past for removing embolic debris temporarily obstructs the artery and then draws the embolic debris from the vasculature by suction. A disadvantage is the temporary obstruction can threaten life or organ survival. Another method breaks up the embolic debris into small pieces for removal from the vasculature. Disadvantages include difficulty in controlling size of the fragments and possibility of damaging nearby tissue. Other methods include embolic capture or diversion by means of stand-alone filter devices, which are positioned to protect specific vessels, but that do not function as conduits or guides for delivering therapeutic devices. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention seeks to provide novel devices and methods for improving the safety and efficacy of percutaneous treatment of vasculature and devices introduced into the vasculature, such as aortic valves, as is described more in detail hereinbelow. In one embodiment, there is a guidance and protection sleeve that can be positioned in the aorta or other body lumen. The guidance and protection sleeve can be used to accurately position a catheter (or new valve) for deployment by guiding the catheter (or the new valve) into the center of the native valve, without scraping the potentially calcified or atheromateous aortic wall. In another embodiment, the invention describes a percutaneous sleeve that slides over a catheter. 
         [0005]    The term “catheter” as used herein, encompasses any percutaneous device, such as but not limited to, a catheter, cannula, guidewire, stent, certain transcatheter aortic valve implantation (TAVI) devices, and others. The catheter may be a treatment catheter, diagnostic catheter, imaging catheter, etc. In some embodiments, the protection sleeve can create an enclosed (or partly enclosed) region above the native valve leaflets (above or below the coronary ostia), in order to capture or divert away from the cerebral vasculature any embolic debris that might be created during impact, decalcification, dilation (such as by balloon valvuloplasty) or implantation of the new valve. 
         [0006]    In some embodiments, the device can be used for assisting the delivery of catheters through blood vessels by reducing the risk of scraping or perforating the blood vessel walls during catheter delivery and retrieval. The device can transform its shape after it is delivered, and before use in catheter delivery. For example, the device expands after delivery to the site before catheter delivery. Catheters may be delivered through a lumen in the device. The device can assist relative positioning of the catheter vis-à-vis the anatomy. The device can assist in centering the catheter in the aorta. The device can aid in the capture or diversion of embolic debris created during treatment. 
         [0007]    There is provided in accordance with one embodiment of the present invention, a method including introducing a protection sleeve in a body lumen, wherein proximal and distal end caps are attached to proximal and distal ends, respectively, of the protection sleeve, and wherein the proximal end cap is slidingly mounted along an outer perimeter of a catheter, and the distal end cap is affixed (or alternatively can slide with respect) to a distal portion of the catheter, and one or more manipulation elements are attached to the protection sleeve, wherein the protection sleeve is in a contracted state upon entry into the body lumen, manipulating the one or more manipulation elements to slide the proximal end cap distally (or the distal end proximally, or any combination thereof) so as to radially expand the protection sleeve, and positioning a section of the protection sleeve so that it blocks emboli from passing therethrough. 
         [0008]    In accordance with an embodiment of the present invention, the method includes allowing emboli to flow into a distal axial end portion of the protection sleeve, and to flow out of a proximal axial end portion of the protection sleeve. 
         [0009]    In accordance with an embodiment of the present invention, the method includes manipulating the one or more manipulation elements to slide the proximal end cap proximally so as to radially contract the protection sleeve, and removing the protection sleeve from the body lumen. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which: 
           [0011]      FIG. 1  is a simplified illustration of anatomy of a calcified aorta. 
           [0012]      FIG. 2  is a simplified illustration of a guiding and protection sleeve, constructed and operative in accordance with a non-limiting embodiment of the present invention. 
           [0013]      FIG. 3  is a simplified illustration of one possible function of the guidance and protection sleeve, which is to guide and control the position of a catheter relative to anatomy, such as the aorta and valve. 
           [0014]      FIG. 4  is a simplified illustration of another non-limiting embodiment of the guiding and protection sleeve, and another function that it potentially has, to reduce the potential scraping of the vascular walls by the catheter during delivery and retrieval of the catheter. 
           [0015]      FIG. 5  is a simplified illustration of a function of the guiding and protection sleeve as a diverter of potential calcific emboli. 
           [0016]      FIGS. 6 and 7  are simplified illustrations of a protection sleeve, constructed and operative in accordance with a non-limiting embodiment of the present invention, respectively before and after assembly on a catheter, wherein in  FIG. 7 , the protection sleeve is in a contracted state prior to delivery into a body lumen. 
           [0017]      FIG. 8  is a simplified illustration of the protection sleeve in a semi-expanded state during delivery into a body lumen, in accordance with a non-limiting embodiment of the present invention. 
           [0018]      FIG. 9  is a simplified illustration of the protection sleeve in a fully-expanded, deployed state after delivery into a body lumen, in accordance with a non-limiting embodiment of the present invention. 
           [0019]      FIG. 10  is a simplified illustration of the deployed protection sleeve positioned to protect carotid takeoffs from emboli entering therein, in accordance with a non-limiting embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0020]    Reference is now made to  FIG. 1 , which illustrates the anatomy of a calcified aorta. The aortic valve includes three leaflets (or two leaflets in bicuspid valves) that throughout the years can develop calcifications, which reduce leaflet mobility and lead to aortic stenosis. Above the valve leaflets are the sinuses with coronary ostia, and the ascending aorta. The carotid artery takeoffs are on the upper part of the aortic arch. 
         [0021]    Reference is now made to  FIG. 2 , which illustrates a guiding and protection sleeve  10 , constructed and operative in accordance with a non-limiting embodiment of the present invention. Sleeve  10  is shown in a deployed position, preferably anchored by means of one or more anchoring members  12  on its distal side to the aortic wall in the ascending aorta. A retractable sheath  14 , shown in an already retracted position, may be used to openexpand the anchoring members  12 . 
         [0022]    Sleeve  10  is shown in use with a catheter  16 . Without limitation, the illustrated catheter  16  is a mechanical impactor catheter, described in PCT patent applications PCTUS2009051784 or PCTUS1058810. Catheter  16  includes an impactor element  18  (in the left ventricular outflow tract (LVOT) below the valve) and a stabilizer element  20  (in the aorta above the valve). Catheter  16  crosses the valve over a guidewire  22  in a closed configuration, and is then opened for treatment. A handle  24  is used to control the operation of catheter  16 . 
         [0023]    Reference is now made to  FIG. 3 , which illustrates one possible function of the guidance and protection sleeve  10 , which is to guide and control the position of the catheter  16  relative to anatomy, such as the aorta and valve. Since the catheter  16  preferably goes through the main lumen of sleeve  10 , the axial and transverse position of the distal part of sleeve  10  affects the transverse position of catheter  16 . The position of the distal part of sleeve  16  relative to the anatomy (such as the aorta, sinuses or the aortic valve) can be established by using one or more distal anchoring members  12  (e.g., funnel, struts, wings, pads, and the like, which may be optionally expandable by balloon expansion or shape memory expansion or expanded by guidewire manipulation) that come into contact with the anatomy, or by pre-setting the shape of the guiding and protection sleeve  10  to fit the particular anatomy. This positioning function can be important in cases where the catheter  16  needs to be positioned approximately at the center of the aorta above the valve. In the case of the impactor catheter  16 , the impactor element  18  can be used to center the distal portion of the impactor catheter  16  at the LVOT, and the distal anchoring member(s)  12  of the guidance and protection sleeve can be used to ensure that the stabilizer element  20  is aligned axially. This means the central axis of catheter  16  passing through the stabilizer  20  and impactor  18 , approximately coincides with the central axis of the ascending aorta, and is approximately perpendicular to the valve plane. 
         [0024]    Reference is now made to  FIG. 4 , which illustrates another non-limiting embodiment of the guiding and protection sleeve  10 , and another function that it potentially has, namely to reduce the potential scraping, dissection or perforation of the vascular walls by the catheter  16  during delivery and retrieval of the catheter  16 . In this embodiment, sleeve  10  includes distal anchoring member(s)  12  and a main lumen  26 . The main lumen  26  is preferably designed to allow perfusion of blood through pores  28  in its material. There are numerous methods known in the art to produce such perfusion, such as, but not limited to, braiding of metal wires, a laser-cut metal tube, a metal structure (braided or other) covered by a polymer with pores, GORE-TEX material, etc. If the pores  28  surrounding the main lumen are small enough (preferably in the range of 100-500 microns), then blood can perfuse through these pores, but any relevant (potentially damaging) embolic debris remains within the main lumen and flow downstream. 
         [0025]    The embodiment described in  FIG. 4  further includes larger, embolic release pores  30 , which are preferably more than 500 microns in size. Large pores  30  can be placed in the descending aorta, so that any potential emboli flowing through the main lumen can be released to the descending aorta, avoiding the cerebral vasculature, thereby reducing the risk for stroke. It is also possible not to include embolic release pores  30 . In such case, any potential emboli will be trapped inside the main lumen, and then removed from the patient body when sleeve  10  is finally removed. Optionally, sleeve  10  may include main lumen  26  without any pores at all, e.g., a solid polymer with or without a metallic structure. If main lumen  26  does not have pores, then blood cannot perfuse through main lumen  26 , and some pores (large or small) preferably need to be incorporated downstream, in order to allow proper blood flow through the main lumen. It will readily be understood that any combination of cover types, porous or non-porous, may be used in any of the segments of sleeve  10 , such as in the distal anchoring member(s)  12 , over segments of the main lumen  26 , and downstream in the descending aorta. The distal anchoring member(s)  12  can be designed to cover the entire cross-section of the aorta or part of the cross section of the aorta. It is also possible not to include distal anchoring of sleeve  10 , but to hold or fix sleeve  10  on its proximal side, in the vicinity of the introducer shaft, and to use the mechanical strength of the sleeve structure in order to hold its distal part in place so it does not migrate. 
         [0026]      FIG. 4  further shows retraction elements  32  (e.g., wires), that can be used to hold sleeve  10  in place during the procedure, and then to retrieve sleeve  10  at the end of the procedure.  FIG. 4  further shows the catheter  16  (such as the impactor catheter, TAVI delivery system, balloon valvuloplasty catheter, decalcification catheter, etc.) as delivered through sleeve  10 . It can be readily understood that the guiding and protection sleeve  10  acts as a buffer or protection layer separating the catheter  16  from the vessel wall, and especially from the aortic arch and ascending aorta, where scraping of the wall can lead to release of debris, and even perforation. 
         [0027]    Reference is now made to  FIG. 5 , which illustrates the function of the guiding and protection sleeve  10  as a diverter of potential calcific emboli, if such embolic debris are created following treatment of the aortic valve. Emboli are collected by the distal anchoring member(s)  12 , flow through the main lumen  26  and out of the emboli release pores  30 , avoiding the carotid takeoffs. If either the distal anchoring member(s)  12  or the main lumen  26  of sleeve  10  are made of porous material, then blood can flow through the pores into the aorta and carotid takeoffs. 
         [0028]    Reference is now made to  FIGS. 6 and 7 , which illustrate a protection sleeve  110 , constructed and operative in accordance with a non-limiting embodiment of the present invention. Protection sleeve  110  may be constructed from a medically safe plastic, metal or other material, such as without limitation, stainless steel, shape memory alloy, titanium alloy, polymers, etc. 
         [0029]    In one preferred construction, protection sleeve  110  is formed of braided wire or mesh. Constructing protection sleeve  110  with braided wire technology has the advantage that the “pitch” of each wire can be relatively large when in the contracted state and then relatively small when in the fully expanded state. In the contracted state, the pores created by the braided wires have elongated “diamond” shapes (long and narrow) and therefore add minimal thickness to the catheter. In the expanded state, the pores have transverse “diamond” shapes (short and wide), that is, a very small pore size, which is advantageous for embolic protection. In summary, using braided wire technology, a relatively low profile (but long) sleeve can transform into a large expanded diameter sleeve with very small pore size. 
         [0030]    End caps  112  and  114  are attached to proximal and distal ends, respectively, of protection sleeve  110 . End caps  112  and  114  may be made of the same or different material as protection sleeve  110 . Protection sleeve  110  together with end caps  112  and  114  are assembled on a catheter  116 . The proximal end cap  112  is arranged to slide along the outer perimeter of catheter  116 , whereas the distal end cap  114  is affixed to a distal portion of catheter  116 . Alternatively, the proximal cap can be fixed, and the distal cap can slide, or both caps can slide, as long as the length of the sleeve can be varied. 
         [0031]    One or more manipulation elements  118 , such as but not limited to, push and/or pull wires, or alternatively shafts, are attached to protection sleeve  110 . As will be explained below, manipulation elements  118  may be used to radially expand or contract protection sleeve  110  for deployment of removal of the sleeve. 
         [0032]    In  FIG. 7 , protection sleeve  110  is in a contracted state prior to delivery into a body lumen. “Contracted” refers to the radial direction about the catheter  116 ; the protection sleeve  110  is elongate in the axial direction in this state. When in the axially elongated state, protection sleeve  110  adds minimal thickness to the contour of catheter  116 . 
         [0033]    Reference is now made to  FIG. 8 , which illustrates protection sleeve  110  in a semi-expanded state during delivery into the body lumen. The manipulation elements  118  are manipulated to push sleeve  110  towards the distal end of catheter  116 . It is noted that the axial length of protection sleeve  110  decreases during radial expansion of the sleeve. In one embodiment of the invention, the manipulation elements  118  cause uniform expansion and contraction of sleeve  110 . In another embodiment of the invention, a plurality of manipulation elements  118  can be affixed to different axial or radial positions of sleeve  110 , so that some of manipulation elements  118  can be manipulated independently and/or differently than other manipulation elements  118  (as shown in broken lines in  FIG. 8 ). For example, some can push while others remain unused; some can be pushed to different degrees than others. This can be used to effect non-uniform expansion and contraction of sleeve  110  (e.g., creating different sinusoidal or wavy patterns). 
         [0034]    Reference is now made to  FIG. 9 , which illustrates protection sleeve  110  in a fully-expanded, deployed state after delivery into the body lumen. In this configuration, protection sleeve  110  reaches its maximum expanded diameter and shortest axial length. The braided or meshed construction of sleeve  110  allows for different size pores at different positions in the sleeve. For example, at axial end portions  120  of sleeve  110 , there is a relatively open mesh (i.e., large pore size). This facilitates entry and exit of emboli into the sleeve  110 . In contrast, at a middle section  122  of sleeve  110 , extending between the end portions  120 , the mesh or braid is very dense (i.e., small pore size). This ensures that virtually no emboli will pass through middle section  122  of sleeve  110 . 
         [0035]    Reference is now made to  FIG. 10 , which illustrates the deployed protection sleeve  110  deployed in the aortic arch and positioned to protect carotid takeoffs  124  from emboli entering therein, in accordance with a non-limiting embodiment of the present invention. The protection sleeve  110  diverts and traps potential calcific emboli, if such embolic debris are created during a surgical procedure, such as but not limited to, valve repair or replacement surgery. Emboli  126  flow into the distal axial end portion  120  of sleeve  110  and flow out of the proximal axial end portion  120  of sleeve  110 . The middle section  122  of sleeve  110  blocks emboli  126  from entering the carotid takeoffs  124 . Protection sleeve  110  does not impede or interfere with blood flow. After the procedure is completed, the sleeve  110  can be retracted to its contracted state and removed from the lumen. In another possible embodiment, the typical pore size of section  120  “downstream” is designed small enough in order to capture emboli that are large enough. Section  120  located “upstream” can have an increased pore size, so that emboli can flow into the protection sleeve through the “eyes” and then be captured downstream.