Abstract:
A catheter for delivering an implant, the catheter comprising a shaft having a proximal end and a distal end and a bore; a first joint in the shaft, the first joint being configured to permit adjacent portions of the shaft to rotate in relation to each other; a second joint in the shaft located distal of the first joint, the second joint being configured to permit adjacent portions of the shaft to rotate in relation to each other; wherein, the first joint and the second joint are separated by a first digit that is rotationally rigid at all points between the first joint and the second joint; further wherein, the second joint and the distal end are separated by a second digit that is rotationally rigid at all points between the second joint and the distal end, the second digit being sized to receive an implant.

Description:
BACKGROUND 
       [0001]    This application relates to systems and methods for implanting devices such as replacement heart valves, clips, stents, and similar repair devices within the anatomy of a patient. 
         [0002]    It is well known in the art to implant devices such as replacement heart valves, clips, stents, and reinforcement rings, and the like into the human heart to repair the function of the human heart. Similar devices are also introduced into other parts of the human anatomy where mechanical repair is needed. Many such repair operations are carried out by first inserting a delivery catheter by minimally invasive means into a desired organ of the human anatomy. Thereafter, a repair device is passed through an internal lumen along the entire length of the delivery catheter until the repair device reaches the target organ, and the device is pushed out of the distal end of the catheter for implantation. Such devices may expand to assume a new shape once they are pushed out of the delivery catheter, some by means of self-expansion, others by means of mechanical expansion via balloons, expanders, and the like. 
         [0003]    One of the problems confronted by such systems known in the art is that the delivery catheter may require to be threaded through a tortuous series of twists and turns through one or more lumens in the patient&#39;s anatomy. Once the delivery catheter is in position, the implant device must be pushed up, from outside the patient, through a lumen of this tortuously twisted delivery catheter. If the implant device has a substantial profile in its delivery condition, the surgeon may encounter difficulty in threading the implant device around all the tight corners of the delivery catheter. Further, once the implant device reaches the distal end of the delivery catheter, the surgeon may find that she has no control over the orientation of the distal end of the catheter because the catheter has effectively neither tortional stiffness, nor longitudinal stiffness extending unbroken all the way from the proximal end where a control handle is located, to the distal end where the device will eventually be delivered. Although delivery catheters may include pullwires to facilitate positioning the catheter&#39;s distal tip in a three dimensional space, such pullwire systems are frequently difficult to operate and not reliable for exact positioning. 
         [0004]    Therefore there exists a need in the art for improved systems and methods for delivering implant devices to a distal end of a delivery catheter, and once having so delivered, to be able to manipulate the distal end of the catheter by manipulating the proximal end of the catheter. The present invention addresses these and other needs. 
       SUMMARY OF THE INVENTION 
       [0005]    In one embodiment, the invention is a method of delivering an implant into a heart of a patient, the heart having a left atrium and a right atrium. The method comprises creating an entryway into the anatomy of a patient via a femoral artery. Then a trans-septal puncture is performed between the right atrium and the left atrium. A catheter is inserted into the patient via the femoral artery. The catheter has a proximal end communicating via a bore to a distal end. The catheter has a first joint, and a second joint that is located distal of the first joint, wherein, the first joint and the second joint are separated by a first digit that is rotationally rigid at all points between the first joint and the second joint, and further wherein the second joint and the distal end are separated by a second digit that is rotationally rigid at all points between the second joint and the distal end. The catheter is advanced into the patient until the first joint and the distal end are located in the right atrium and an implant is located, within the bore, distal of the first joint. The first joint is bent. The distal end is passed via the trans-septal puncture into the left atrium until the second joint is located in the left atrium. The implant is moved within the catheter until the implant is located distal of the second joint. One of ordinary skill will appreciate that securing an implant at a location adjacent the distal end of a delivery catheter, inside the left atrium, without having been obliged to push the implant around a number of tortuous bends inside a catheter, is a highly advantageous outcome. 
         [0006]    In some embodiments, the method further includes bending the second joint; and thereafter, it may include manipulating a position of the implant in relation to the heart by rotating the proximal end of the catheter about an elongate axis of the catheter. One of ordinary skill will appreciate that the ability to position the implant in relation to the heart by rotating the proximal end of the catheter is not feasible in current catheters because the current catheters are not tortionally rigid enough between distal end and proximal end to permit such control from the proximal end. Once the implant is positioned at a desirable location, the method may include ejecting the implant from the bore at the distal end, and this may include ejecting the implant towards a mitral valve of the heart. In some embodiments, performing a trans-septal puncture includes routing a guidewire from the femoral artery into the left atrium, and advancing the catheter may include passing the catheter over the guidewire. In some embodiments, bending the first joint may include manipulating pullwires passing through the catheter; and it may also include bending a first joint that is an articulated joint, which in turn may include rotating the articulated joint about a pin connector. 
         [0007]    In another embodiment, the invention may be a catheter for delivering an implant to a desired location within a patient. In some embodiments, the catheter comprises a shaft having a proximal end and a distal end and a bore extending between the proximal end and the distal end. It may also include a first joint in the shaft, the first joint being configured to permit adjacent portions of the shaft to rotate in relation to each other within a single plane. It also includes a second joint in the shaft located distal of the first joint, the second joint being configured to permit adjacent portions of the shaft to rotate in relation to each other within a single plane. Under this configuration, the first joint and the second joint are separated by a first digit that is rotationally rigid at all points between the first joint and the second joint. Furthermore, the second joint and the distal end are separated by a second digit that is rotationally rigid at all points between the second joint and the distal end. Again, under this configuration, the first digit and the second digit, taken together, are sized to receive an implant entirely within the bore between the first joint and the distal end. 
         [0008]    In some embodiments, the first digit is sized to receive an implant entirely within the bore between the first joint and the second joint. In other embodiments, the second digit is sized to receive an implant entirely within the bore between the second joint and the distal end. 
         [0009]    In further embodiments, the second digit includes a conical portion that is flexible in a radial direction. This aspect permits an implant to be forced distally into and through the conical portion, while the conical portion can expand radially to permit passage of the implant. In yet further embodiments, the first joint is an articulating joint, and the articulating joint may include a pin. In further embodiments, the first joint and the second joint are the only joints in the shaft between the proximal end and the distal end. One of ordinary skill will appreciate that by reducing the number of joints, a catheter is formed that has a high degree of torsional rigidity, and permits an operator to rely on that rigidity to position an implant at the distal end, while manipulating the catheter from the proximal end which extends outside the patient. 
         [0010]    These and other advantages will become apparent when read in conjunction with the drawings and the detailed description of embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a front view schematic representation of the human venous circulatory system including the heart and the great veins; 
           [0012]      FIG. 2  is a front view schematic representation of the man venous circulatory system with a guidewire routed from the femoral vein into the right atrium; 
           [0013]      FIG. 3  is a front view schematic representation of the human venous circulatory system with an expandable sheath advanced into the right atrium; 
           [0014]      FIG. 4  is a cross-sectional illustration of the heart with the expandable sheath positioned at the atrial septum and the septal penetrator advanced across the atrial septum into the left atrium, according to an embodiment of the invention; 
           [0015]      FIG. 5  is a cross-sectional illustration of the heart with the expandable sheath advanced into the left atrium across the atrial septum and the septal penetrator withdrawn into the dilator of the expandable sheath, according to an embodiment of the invention; 
           [0016]      FIG. 6A  is a cross-sectional illustration of the heart with a novel catheter advanced into the right atrium according to an embodiment of the invention. 
           [0017]      FIG. 6B  is a cross-sectional illustration of the novel catheter seen in  FIG. 6A . 
           [0018]      FIG. 7A  is a cross-sectional illustration of the heart with the catheter of  FIGS. 6A and 6B  advanced into the right atrium according to an embodiment of the invention. 
           [0019]      FIG. 7B  is a cross-sectional illustration of the novel catheter in the configuration seen in  FIG. 7A . 
           [0020]      FIG. 8  is a cross-sectional illustration of the novel catheter in a further bent configuration according to an embodiment of the invention. 
           [0021]      FIG. 9A  is a cross-sectional illustration of the heart with the catheter of  FIGS. 6A and 6B  advanced into the right atrium and bent according to an embodiment of the invention. 
           [0022]      FIG. 9B  is a cross-sectional illustration of the novel catheter in the configuration seen in  FIG. 9A . 
           [0023]      FIG. 10A  is a cross-sectional illustration of the heart with the catheter of  FIGS. 6A and 6B  advanced into the right atrium according to an embodiment of the invention, and delivering a first type of implant. 
           [0024]      FIG. 10B  is a cross-sectional illustration of the novel catheter according to an embodiment of the invention, delivering another type of implant. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0025]    As may be understood from this detailed description, as read in conjunction with the figures, a catheter having features of the invention is described. The context of the invention is explained with initial reference to  FIGS. 1-5 . 
         [0026]    Referring to  FIG. 1 , there is shown a schematic frontal illustration, looking posteriorly from the anterior side of the patient  100 . The heart  102  is a pump, the outlet of which is the aorta, including the descending aorta  104 , which is a primary artery in the systemic circulation. The circulatory system, which is connected to the heart  102  further comprises the return, or venous, circulation. The venous circulation comprises the superior vena cava  108  and the inferior vena cava  106 . The right and left jugular veins,  110  and  112 , respectively, and the subclavian vein  114  are smaller venous vessels with venous blood returning to the superior vena cava  108 . The right and left femoral veins,  116  and  118  respectively, return blood from the legs to the inferior vena cava  106 . The veins carry blood from the tissues of the body back to the right heart, which then pumps the blood through the lungs and back into the left heart. The arteries of the circulatory system carry oxygenated blood (not shown) from left ventricle of the heart  102  to the tissues of the body. 
         [0027]      FIG. 2  (prior art) shows that a vascular introduction sheath  204  has been inserted into the right femoral vein  116  via a percutaneous puncture or incision. A guidewire  200  has been inserted through the introduction sheath  204  and routed up the inferior vena cava  106  to the right atrium  202 , one of the chambers of the heart  102 . In this illustration, the left anatomical side of the patient  100  is toward the right. The guidewire  200  has been placed so that it can be used to track a delivery catheter into a region of the heart  102 . 
         [0028]      FIG. 3  (prior art), is a frontal illustration, looking posteriorly from the anterior side, of the patient  100 . The vascular introduction sheath  204  of  FIG. 2  has been removed from the right femoral vein  116  and a larger trans-septal expandable sheath  300  has been inserted into the venous circulation over the guidewire  200  and routed through the inferior vena cava  106  into the right atrium  202  of the heart  102 . The expandable trans-septal sheath  300  further comprises a dilator  306 , the proximal most part of which is shown in  FIG. 3 . The expandable trans-septal sheath  300  further comprises a proximal non-expandable region  304  and a distal expandable region  302 . 
         [0029]      FIG. 4  (prior is a cross-sectional illustration of the heart  102 , showing the atrial septum  504 . The distal expandable region  302  of the sheath  300 , substantially located within the right atrium  202 , is shown with its long axis perpendicular to the atrial septum  504 . The proximal end  304  of the sheath  300  is shown resident within the inferior vena cava  106 . A septal penetrator  500  is shown extended through a puncture  502  in the atrial septum  504  and is routed into the left atrium  404 . The septal penetrator  500  is a needle or axially elongate structure with a sharp, pointed distal end. The septal penetrator  500  is actuated at the proximal end of the sheath  300 . The septal penetrator  500  is operably connected to a control mechanism such as a button, lever, handle, trigger, etc., which is affixed, permanently or removably, at the proximal end of the dilator  306  by way of a linkage, pusher rod, or the like that runs the length of the dilator  306 . 
         [0030]      FIG. 5  (prior art), illustrates a cross-sectional view of the heart  102  showing the distal expandable region  302  having been advanced across the atrial septum  504  from the right atrium  202  and into the left atrium  404 . The tapered tip  600  of the dilator  306  leads the distal end of the expandable region  302  through the septal puncture  502  created by the penetrator  500 . 
         [0031]    Once the puncture  502  is successfully formed in the septum  504 , a guidewire  200  is redirected down the catheter  300  to extend into the left atrium  404 , and the catheter  304  is removed from the patient&#39;s anatomy, while leaving the guidewire  200  in position. The foregoing is a method known in the art for placing a guidewire across a puncture in the septum, as exemplified in U.S. Publication 20060135962, incorporated herein in its entirety. 
         [0032]    At this point a novel catheter  700  according to embodiments of the present invention is described starting with reference to  FIG. 6A  and  FIG. 6B . The catheter  700  is introduced over the guidewire  200  until the distal end  701  of the catheter protrudes into the right atrium  202 . 
         [0033]    Before proceeding to describe an embodiment of a novel method for delivering an implant once the septum  504  has been punctured, a novel catheter is described here that is suitable for carrying out embodiments of the invention. With reference to  FIG. 6A  and  FIG. 6B , the catheter  700  of the present invention is designed and configured to provide the surgeon user with a delivery instrument for advancing a relatively inflexible implant device  710  to a desired location in the human anatomy. The invention is not limited by the type of implant device, and this may take the form of a heart valve, a clip, a stent, a reinforcement ring, or similar. 
         [0034]    It will be understood by one of ordinary skill, and with reference to  FIG. 3  that the shape assumed by the catheter  700 , as it is extended from the femoral artery at the proximal end all the way to the right atrium  202 , follows a profile that is substantially a straight or linear configuration. As will be described, it is only at the very distal end of its travel that the shape of the catheter  700  will be required to depart from a substantially straight configuration for its proper use. 
         [0035]    In order to provide this characteristic, the catheter  700  is fabricated so that it is substantially stiff all the way along its length from its proximal end to near its distal end, and is at least stiff enough to receive a distally directed force exerted by the user without buckling. However, at its distal end the catheter is provided with two specific points of articulation, a first point of articulation at a proximal joint  702  and a second point of articulation at a distal joint  704 . 
         [0036]      FIG. 6B  exemplifies the structure of a joint that will be suitable to accomplish the objective of this embodiment of the invention. Each joint is configured to make a sharp turn, and in some embodiments the joints are configured to articulate about a pin  712 . In other embodiments, the joint may be configured to articulate about a ball and socket joint, or other known system or articulation. Such joints are described more fully in application Ser. No. 13/675,934, which is incorporated herein in its entirety. 
         [0037]    In some embodiments, the joints  702 ,  704  described are configured to bend away from a straight configuration in only one plane, and then to stop bending when a limit of travel has been reached. For example,  FIGS. 7A and 7B  show that the first joint  702  has been bent through an angle α which allows the distal end  701  of the catheter to be extended through the puncture  502  that has been made in the septal wall  504  as described herein. Both first joint  702  and second joint  704  are configured so that after a limited angle of bending has been travelled, the joint can bend no further, and is effectively “locked” against further movement. The movement of the joint into a bent condition is effected by pullwires (which, for sake of clarity, are not shown in the figures) that are positioned to extend axially along the circumference of the catheter according to known technology such as that described in application Ser. No. 13/675,934, and incorporated herein. 
         [0038]    The section of the catheter that lies between the first joint  702  and the second joint  704  is referred to herein as the proximal digit  706  (or first digit) and the section that extends between the second joint  704  and the distal end  701  as the distal digit  708  (or second digit). In some embodiments, these digits are rigid and are configured to not possess additional joints within the length of each one of them. These qualities in the digits  706 ,  708  are referred to herein as being “rotationally rigid.” Therefore, when the first joint  702  and second joint  704  are the only joints in the catheter, and when they are locked into a bent configuration by forces exerted through pullwires, they are configured to faithfully transmit any movement (rotational or translational) of the proximal end of the catheter to the distal end  701  thereof. At the distal end of the distal digit  708 , a flexible cone  709  may be affixed. This cone provides a narrowed and pointed end that facilitates passing the distal end  701  of the catheter through the septal puncture  502  and may be fabricated from a suitable flexible polymer. The cone is radially flexible in order to permit an implant  710  to be pushed out of the distal end of the bore  714  that extends through the catheter. The cone will be expanded by the implant as it is forced distally through the cone. 
         [0039]    In use, the invention is applied as follows. A desired implant  710  is inserted into the bore  714  of the catheter, and is advanced distally until it is positioned inside the proximal digit  706  so that it is positioned entirely between the first joint  702  and the second joint  704  as seen in  FIG. 6B . The implant may be a clip designed to repair a mitral valve (as is exemplified in  FIG. 6B ) or it may be a prosthetic mitral valve, or other implant type device known in the art for repairing body organs. A flexible push rod  716  is attached to the proximal end of the implant  710  and extends down the bore  714  of the catheter to the proximal end of the catheter. The push rod is suitable for developing sufficient column strength to push the implant distally and to control the deployment of the implant  710  once it has been ejected from the catheter according to known means. Control wires  711  may be attached to the implant to control the implant during and after deployment. 
         [0040]    The catheter  700  is then advanced over the guidewire  200  from the femoral artery at the proximal end, all the way to the right atrium  202 , as may be envisaged by reference to  FIGS. 6A and 6B . It will be appreciated that in the case where an implant occupies the center of the catheter bore  714  (such as exemplified in  FIG. 6B ), it may not be feasible to insert a guidewire down the center of the bore  714 . However, it is well known to provide a lumen for receiving a guidewire that extends along the circumferential wall of the catheter, and such a lumen will be provided in a case where the center of the catheter bore is blocked by an implant. For the sake of clarity such a lumen for a guidewire located on the circumferential wall of the catheter is not shown in the figures, but may be envisaged by reference to U.S. Pat. No. 8,317,715 which is incorporated herein in its entirety. 
         [0041]    At this point in the process, the first joint  702  may be bent by using the pullwires (not shown) so that the distal tip  701  of the catheter faces the puncture  502 ′ in the septal wall  504 ′. The septal wall and puncture  502 ′ are shown in dotted in  FIG. 7B , and the distal tip  701  of the catheter is lined up with the puncture with the aid of the guidewire. Then, the distal tip  701  may be pushed through the puncture  502  as is exemplified in  FIG. 7B  in solid line, until the second joint  704  enters the left atrium when passed through the puncture  502  as exemplified in  FIG. 7B . 
         [0042]    At this point in the process, the implant  710  may be pushed distally within the bore  714  of the catheter using the flexible push rod  716  until it is entirely located in the distal digit  708 , distally of the second joint  704 , as exemplified in  FIG. 8 . It will be appreciated that under this configuration, the flexible cone  709  is forced to expand radially outwardly, losing its conical shape to accommodate the implant  710 . 
         [0043]    Then, when this step is complete, the second joint  704  may be bent using the pullwire system (not shown) so that the distal digit  708  points downward toward the mitral valve  510 , as exemplified in  FIGS. 9A and 9B . At this point, the surgeon may manipulate the location of the distal tip  701  of the catheter by using the pullwires controlling the distal joint  704  to move the distal tip laterally (that is, left and right as seen in  FIGS. 9A and 9B ), and also by rotating the proximal end of the catheter about its elongate axis. Due to the torsional stiffness of the catheter, the distal tip  701  responds to such rotation by moving transversely (that is, in and out of the page as seen in  FIGS. 9A and 9B ). Thus, the surgeon has the ability to locate the distal tip to any point above the mitral valve  510 , ready for the next step. 
         [0044]    During the next step, exemplified in  FIG. 10A  and  FIG. 10B , the implant is pushed out of the bore  714  of the catheter at the distal tip  701 . In  FIG. 10A , an implant  710 ′ is shown, which, for exemplary purposes, is a prosthetic valve; while in  FIG. 10B , an implant  710  is shown which, for exemplary purposes, is a mitral valve clip such as a MitraClip® which is more fully described in U.S. Pat. No. 7,226,467, incorporated herein in its entirety. As noted above, the method of the invention may be carried out using any kind of implant known in the art, and is not limited to implanting valves or clips. 
         [0045]    It will be evident to one of ordinary skill in the art that a minimum dimensional requirement of the invention is that the combined length of the proximal digit  706  and the digital digit  708  must be sufficiently long to accommodate the implant  710  entirely within the bore between the first joint  702  and the distal end  701 . In some embodiments, it may be desirable for the length of the proximal digit  706  to be sufficient to accommodate the implant  710  entirely between the first joint  712  and the second joint  704 . In other embodiments, it may be desirable for the length of the distal digit  708  to be sufficient to accommodate the implant entirely between the second joint  704  and the distal end  701 . However, if the implant, once inserted into the bore  714  of the catheter at a location distal to the first joint  702 , were to extend across the second joint  704 , then the method described above would still be feasible. However, sizing the digits  706 ,  708  to be large enough to accommodate an implant  710  entirely within a single digit gives the catheter the potential to negotiate a patient&#39;s anatomy with greater flexibility in unforeseen circumstances than if the implant extends across the second joint. The configuration chosen for use in a catheter will depend on the type and length of the implant being used, and the nature of human anatomy being targeted for delivery. 
         [0046]    Thus, a novel and advantageous system and method for delivering an implant is described that eliminates the need to advance the implant around a tortuous bend in a catheter. Rather, the implant is pushed down a substantially straight bore of the catheter, and any required bending in the catheter takes place only after the implant has been advanced beyond a joint which provides a bend in the catheter. At no point is the inflexible implant required to navigate around a sharp bend in the catheter. This characteristic greatly facilitates the delivery of lengthy and inflexible implants to remote corners of a patient&#39;s anatomy. 
         [0047]    Although preferred illustrative variations of the present invention are described above, it will be apparent to those skilled in the art that various changes and modifications may be made thereto without departing from the invention. For example, it will be appreciated that combinations of the features of different embodiments may be combined to form another embodiment.