Patent Publication Number: US-11638624-B2

Title: Ultrasonic endovascular catheter with a controllable sheath

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of U.S. patent application Ser. No. 15/425,321, filed Feb. 6, 2017, which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     This document relates generally to the art of endovascular procedures and, more particularly, to an endovascular catheter using ultrasonic energy to perform a medical procedure, such as an atherectomy or crossing an occlusion, using a controllable sheath. 
     BACKGROUND 
     Ultrasonic catheters have been proposed. An example of such a catheter is shown in U.S. Pat. No. 7,540,852, the disclosure of which is fully incorporated herein by reference. While this catheter achieves the desired result of providing enhanced disruption of blood vessel obstructions, the present disclosure proposes certain modifications or improvements to enhance the results achieved during an endovascular procedure in terms of clearing an obstruction from a vessel (such as, for example, an atherectomy for removing atherosclerosis from a blood vessel, or for crossing an occlusion). 
     SUMMARY 
     According to a first aspect of the disclosure, an apparatus for performing an endovascular procedure using ultrasonic energy. The apparatus comprises a catheter including a proximal end portion and a distal end portion having a first window, which may be elongated in a longitudinal direction of the catheter. A wave guide is provided for delivering the ultrasonic energy for performing the endovascular procedure. A cover is also provided for selectively covering the window. 
     In one embodiment, the distal end portion of the catheter includes an opening through which the wave guide may pass. The catheter may comprise a first sheath including the first window. The cover may comprise a rotatable second sheath for covering the first window of the first sheath. The second sheath may include a second window for aligning with the first window, as well as an opening through which the wave guide may pass. 
     According to a further aspect of the disclosure, an apparatus for performing an endovascular procedure is provided. The apparatus includes a source of ultrasonic energy, and a wave guide for delivering the ultrasonic energy for performing the endovascular procedure. A catheter is provided for receiving the wave guide. The catheter includes a first window for transmitting ultrasonic energy from the wave guide and an opening at a distal end through which the wave guide may pass. 
     In one embodiment, a cover is provided for selectively covering the first window, which may be elongated in a longitudinal direction of the catheter. The catheter may comprise a first sheath including the window, and the cover may comprise a rotatable second sheath for covering the window of the first sheath. The second sheath may include a second window for aligning with the window of the first sheath. The second sheath may further include an opening through which the wave guide may pass. 
     Still a further aspect of the disclosure pertains to an apparatus for performing an endovascular procedure using ultrasonic energy. The apparatus comprises a wave guide for delivering the ultrasonic energy for performing the endovascular procedure. A catheter is adapted for selectively blocking or transmitting the ultrasonic energy from the wave guide. 
     In one embodiment, the catheter comprises a first window for exposing a portion of the wave guide. A cover is also provided for covering the first window. The catheter may comprise a first sheath including the first window and a second sheath forming the cover. The second sheath may also comprise a second window corresponding to the first window. One or both of the first and second sheaths may be rotatably mounted to the catheter. A source connected to the catheter may supply ultrasonic energy to the wave guide. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       The accompanying drawing figures incorporated herein and forming a part of the specification, illustrate several aspects of the ultrasonic endovascular catheter with a controllable sheath and, together with the description, serve to explain certain principles thereof. In the drawing figures: 
         FIG.  1    is a schematic view of a prior art catheter system including an ultrasonic catheter; 
         FIG.  2    is a side view illustrating a general layout of a prior art catheter; 
         FIG.  3    is a partially cross-sectional, partially cutaway view of a catheter including an ultrasonic wave guide; 
         FIG.  4    is a side view of a catheter with a controllable sheath according to one aspect of the disclosure; 
         FIG.  5    is a close-up view of the distal end portion of the catheter of  FIG.  4   ; and 
         FIGS.  6  and  7    illustrate an alternate embodiment. 
     
    
    
     Reference will now be made in detail to the presently disclosed embodiments of the inventive aspects of the ultrasonic endovascular catheter with a controllable sheath, examples of which are illustrated in the accompanying drawing figures. 
     DETAILED DESCRIPTION 
     Ultrasound or ultrasonic catheters provide for disruption of occlusions in blood vessels, such as for example, plaques, clots, lesions, or like objects that hinder blood flow. Catheters generally include a catheter body (shaft), an ultrasonic energy transmission member disposed within the catheter body and a distal head coupled with the energy transmission member and disposed at or near the distal end of the catheter body. The ultrasonic wave guide transmits ultrasonic energy from an ultrasonic transducer to the distal end of the catheter, causing it to vibrate and, thus, disrupt, dissolve, or debulk vascular occlusions (which procedures are generally called atherectomies or thrombectomies). A number of improved features of such an ultrasonic catheter are outlined more fully in the following description. 
     Referring now to  FIG.  1   , one embodiment of an ultrasonic catheter system  20  includes an ultrasound or ultrasonic catheter  10  and an energy source  16  (which may comprise an ultrasonic generator). Catheter  10  includes a distal end  26  for disrupting occlusions, a catheter shaft or body  27 , and a proximal connector  12  for coupling catheter  10  with an ultrasonic transducer  14 . Ultrasonic transducer  14  is coupled with source  16  via a connector  28 , and generator is coupled with a control, such as a foot-actuated on/off switch  18  via another connector  29 . Source  16  provides energy to transducer  14  and, thus, to ultrasonic catheter  10 . 
     Catheter  10  further includes an ultrasonic wave guide (or “core wire”—not shown in  FIG.  1   ) that extends through the catheter body  27  and transmits energy from the transducer  14  to the distal end  26 . Some embodiments of catheter  10  include a guidewire, which in  FIG.  1    is shown as a so-called “rapid exchange” guidewire  13  and guidewire port, while other embodiments include a proximal guidewire port for over the wire guidewire delivery. In some embodiments, transducer  14  further includes a coupler  15  for coupling the catheter  10  to transducer  14 . Connectors  28 ,  29  may comprise an electric cord or cable or any other suitable connecting devices for coupling on/off switch  18 , source  16  and transducer  14 . In an alternative embodiment, on/off switch  18  is located on source  16 . 
     In addition to proximal connector  12 , ultrasonic catheter  10  may include one or more other various components, such as a Y-connector  11  including a fluid inlet port  17  (or aperture) for passage of irrigation fluid. Inlet port  17  may be removably coupled with an irrigation tube  24 , which in one embodiment may be coupled with a fluid refrigerator  30 . The refrigerator  30  may, in turn, be coupled with a fluid container  32  via a connector tube  34 . This arrangement may be used for introducing one or more fluids into catheter  10 . Fluid may be used to cool any part of the device, such as the ultrasonic wave guide, thus helping reduce wear and tear on the catheter  10 . In some embodiments, fluid inlet port  17  is located farther proximally on proximal connector  12 , to allow fluid to be applied within connector  12 . In some embodiments, refrigerated fluid is used, while in other embodiments irrigation fluid may be kept at room temperature. In various embodiments, oxygen supersaturated fluid, lubricious fluid, or any other suitable fluid or combination of fluids may be used, and again, such fluids may be refrigerated or kept room temperature. In an alternative embodiment to that shown in  FIG.  1   , refrigerator  30  and fluid container  32  are combined in one unit. 
     Generally, catheter  10  may include any suitable number of side-arms or ports for passage of a guidewire, application of suction, infusing and/or withdrawing irrigation fluid, dye and/or the like, or any other suitable ports or connections. Also, ultrasonic catheters  10  per the disclosure may be used with any suitable proximal devices, such as any suitable ultrasonic transducer  14 , energy source  16 , coupling device(s) and/or the like. Therefore, the exemplary embodiment shown in  FIG.  1    and any following descriptions of proximal apparatus or systems for use with ultrasonic catheters  10  should not be interpreted to limit the scope of the appended claims. 
     Referring now to  FIG.  2   , an enlarged view of catheter  10  is shown. Proximal connector  12 , Y-connector  11 , inlet port  17 , catheter body  27 , distal end  26  and guidewire  13  are all shown. Catheter body  27  is generally a flexible, tubular, elongate member, having any suitable diameter and length for reaching a vascular occlusion for treatment. In one embodiment, for example, catheter body  27  preferably has an outer diameter of between about 0.5 mm and about 5.0 mm. In other embodiments, as in catheters intended for use in relatively small vessels, catheter body  27  may have an outer diameter of between about 0.25 mm and about 2.5 mm. Catheter body  27  may also have any suitable length. As discussed briefly above, for example, some ultrasonic catheters have a length in the range of about 150 cm. However, any other suitable length may be used without departing from the scope of the present disclosure. 
     Referring now to  FIG.  3   , a proximal portion of one embodiment of an ultrasonic catheter  110  is shown in cross-section. An ultrasonic wave guide  140  extends from a sonic connector  152  distally to a distal end (not shown) of catheter  110 . A catheter body  127  of catheter  110  is shown only in part in this Figure, whereas catheter body may extend distally to (or near) the distal end of catheter  110 , as shown in  FIG.  4   , with the wave guide  140  also extending a particularly long distance (e.g., 30 centimeters or greater, and typically between about 15 centimeters and 30 centimeters). The catheter body  127  may be a constant diameter, or may have a variable diameter from the proximal to the distal end (such as, for example, wider in diameter at the proximal end near the point of entering the vasculature than at the distal end). 
     Catheter  110  also includes a proximal housing  112  (or “proximal connector”), having an inner bore  144  (or “inner cavity”) in which sonic connector  152 , a portion of ultrasonic wave guide  140  and one or more vibration absorbers  150  reside. Housing  112  is coupled with a Y-connector  111 , which includes a fluid inlet port  117  (or aperture), and Y-connector  111  is coupled with catheter body  127 . 
     In various embodiments, housing  112  may suitably include one or more surface features  142  for increasing the overall surface area of the outer surface of housing  112 . Increased surface area enhances the ability of housing  112  to dissipate heat generated by ultrasonic wave guide  140  out of catheter  110 . Surface features  142  may have any suitable size or shape, such as ridges, jags, undulations, grooves or the like, and any suitable number of surface features  142  may be used. Additionally, housing  112  may be made of one or more heat dissipating materials, such as aluminum, stainless steel, any other conductive metal(s), or any suitable non-metallic conductive material(s). 
     In most embodiments, ultrasonic wave guide  140 , such as wire, extends longitudinally through a lumen of catheter body  127  to transmit ultrasonic energy from an ultrasonic transducer  14  (not shown in  FIGS.  2  and  3   ), connected to the proximal end of proximal housing  112 , to the distal end of catheter  110 . Wave guide  140  may be formed of any material capable of effectively transmitting ultrasonic energy from the ultrasonic transducer  14  to the distal end of catheter body  127 , including but not limited to metals such as pure titanium or aluminum, titanium or aluminum alloys, or shape memory materials (such as nitinol), and may be coated (such as using a polymeric material). Again, additional details of ultrasonic wave guides  140  may be found in the patent applications incorporated by reference. Similarly, reference may be made to the incorporated references for descriptions of housing  112 , sonic connector  152 , vibration absorbers  150 , Y-connector  111  and the like. For example, housing  112  and other features are described in U.S. Pat. No. 7,335,180, the disclosure of which is incorporated herein by reference. 
     Ultrasonic wave guide  140  typically passes from a sonic connector  152 , through bore  144  and Y-connector  111 , and then through catheter body  127 . Fluid inlet port  117  is in fluid communication with a lumen in Y-connector, which is in fluid communication with a lumen extending through catheter body  127 . Thus, fluid introduced into fluid inlet port  117  is typically free to flow into and through catheter body  127  to contact ultrasonic wave guide  140 . Fluid may flow out of catheter body  127  through apertures in the distal head (not shown) or through any other suitable apertures or openings, such as apertures located in catheter body  127  itself. Any suitable fluid may be passed through fluid inlet port  117  and catheter body  127 , such as refrigerated fluid, lubricious fluid, super-saturated saline or contrast/saline mixture, or the like. Cooling and/or lubricating ultrasonic wave guide  140  may reduce friction and/or wear and tear of ultrasonic wave guide  140 , thus prolonging the useful life of ultrasonic catheter  110  and enhancing its performance. 
     Referring now to  FIG.  4   , it can be understood that the catheter body  127  may take the form of a sheath  127   a  in which the wave guide  140  is at least partially positioned. The proximal end of the sheath  127   a  may be positioned adjacent to the housing  112 , and may extend within the Y-connector  111 , as shown in  FIG.  3   , or may be external to it, as shown in  FIG.  4   . In either case, the sheath  127   a  may be adapted to rotate relative to the wave guide  140 , as indicated by action arrow R. Alternatively, the sheath  127   a  may be fixed in position relative to the connector  111  or housing  112 . 
     The sheath  127   a  may also include a lateral or side opening, such as a window  127   b , adjacent to a portion of the wave guide  140 , and thus exposing it to the interior of a lumen or vessel when positioned therein. As indicated in  FIG.  5   , the sheath  127   a  may be rotated relative to the wave guide  140 , such that the direction of the ultrasonic energy is controlled by the position of the window  127   b  (note action arrows E) or, alternatively, the entire catheter  110  may be rotated if the sheath is fixed. In either case, by selectively controlling the position of the window  127   b  through rotation, a focused or targeted treatment may be provided for a particular area of the vessel in which the catheter  110  is at least partially positioned, since only a portion of the wave guide  140  is exposed to the opening thus formed. 
     To allow for an enhanced level of control, the window  127   b  may also be selectively blocked. This may be achieved by providing a cover  128  for selectively covering the opening or window  127   b  in the sheath  127   a . As indicated in  FIGS.  6  and  7   , the cover  128  may comprise a second sheath  128   a  over the first sheath  127   a , such that the two structures are generally concentric about the wave guide  140 . This second sheath  127   a  may also extend to the proximal end of the catheter  110 , such as adjacent to or within the connector  111 , and may include an open end  128   c . The second sheath  128   a  may further include a lateral or side opening, such as a window  128   b , which may have a size and shape matching or corresponding to window  127   b  in the first sheath  127   a.    
     Thus, as indicated in  FIG.  6   , the second sheath  128   a  may be rotated relative to the first sheath  127   a  (which may be fixed or stationary, or also rotatable as noted above) such that the window  127   b  is covered by a portion of the second sheath. In this manner, the energy may be directed to wave guide  140  through the open end  127   c  of the sheaths  127   a ,  128   a , and the catheter  110  may be used in crossing a chronic total occlusion (CTO) in this configuration. 
     When it is desired to allow for ultrasonic energy to be transmitted radially of the longitudinal axis of the catheter  110 , the second sheath  128   a  may be rotated to align the windows  127   b ,  128   b . This allows the energy (arrow E) to pass into the vessel through the opening thus formed, as shown in  FIG.  7   . The relative rotation may also be achieved such that the opening only partially exposes the wave guide  140 , which may provide for a further level of control. 
     Control of the relative rotation may be achieved at the proximal end of the catheter by providing suitable markings on the sheaths  127   a ,  128   a  to indicate the aligned position of the openings or windows  127   b ,  128   b . The markings may be in the form of printed indicia, but may also take the form of bosses or embosses (and may be arranged to interact to create a temporary locked condition). Alternatively, radiographic visualization may be used, such as by providing one or more radiopaque markers on the periphery of the windows  127   b ,  128   b . Alignment of the markers under fluoroscopy may indicate the aligned position of the windows. 
     In summary, an improved ultrasonic catheter  110  includes a controllable sheath  127   a  or  128   a . One or both of the sheaths  127   a ,  128   a  may include windows  127   b ,  128   b  and may be adapted for relative rotation. By aligning the windows  127   b ,  128   b  to form an opening, the transmission of energy from a wave guide  140  associated with the catheter  110  may result. Yet, the catheter  110  may also be used in a “crossing” mode, such as for crossing a CTO, by reorienting the sheaths  127   a ,  128   a  and thus closing the opening formed by the windows  127   b ,  128   b  and regulating the transmission of ultrasonic energy. 
     The foregoing description has been presented for purposes of illustration. It is not intended to be exhaustive or to limit the embodiments to the precise form disclosed. Obvious modifications and variations are possible in light of the above teachings. For instance, instead of rotatable sheaths  127   a ,  128   a , one or both of the sheaths may be made to telescope relative to each other to selectively uncover or block the opening for transmitting energy radially from the wave guide  140 . The size and shape of the opening formed by the window  127   b  or  128   b  may also be altered from what is shown in the drawings to suit a particular desire or need in terms of a treatment regimen. All modifications and variations are within the scope of the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.