Patent Description:
<CIT> relates to methods and devices for valve clip excision.

The invention relates to an elongate catheter in accordance with claim <NUM>, a system in accordance with claim <NUM> and an electrosurgical system in accordance with claim <NUM>.

For purposes of illustration, and not limitation, exemplary embodiments of a catheter, which can also be used as a robotic manipulator, are presented in <FIG> and 2A-2D. For purposes of simplicity but not limitation, the devices are typically referred to herein as "catheters" but it will be understood by those of skill in the art that they can equally be considered to be robotic manipulators.

With reference to <FIG>, an elongate catheter is provided having a proximal end and a distal end. The catheter includes an elongate tubular main body <NUM> having a proximal end, a distal end, and defining at least one elongate passage therethrough. The elongate tubular main body defining a longitudinal axis along its length.

The catheter includes a first elongate inner body <NUM> having a proximal end and a distal end. The inner body <NUM> is illustrated with an illustrative cone-shaped atraumatic distal tip <NUM> that is configured to spread applied stress out over a larger area, which can be of particular benefit when contacting delicate anatomical structures. The first elongate inner body <NUM> is slidably disposed within the at least one elongate passage of the elongate tubular main body <NUM>.

Also illustrated is a second elongate inner body <NUM> having a proximal end and a distal end that is slidably disposed within the at least one elongate passage of the elongate tubular main body <NUM>, which is suitably configured to maintain registration of bodies <NUM> and <NUM> with respect to each other and hold them together. Bodies <NUM> and <NUM> can be housed in a common passage, or in individual passages defined within body <NUM>. Body <NUM> is slidably disposed with respect to the first inner body <NUM>, wherein an exposed distal region <NUM> of body <NUM> is illustrated as protruding beyond the distal end of main body <NUM>.

As illustrated, the distal end of the first and second inner elongate bodies <NUM>, <NUM> are preferably biased or otherwise configured to be curled or steered away from the longitudinal axis in a proximal direction when the first elongate inner body is advanced distally with respect to the main body by virtue of inner body <NUM> being removed from body <NUM>. Bodies <NUM>, <NUM> can be configured to curl as illustrated when advanced distally from body <NUM> by making bodies <NUM>, <NUM> at least in part from shape memory materials, and/or by utilizing a steering wire that travels the length of the body <NUM>, <NUM> that is attached to a distal end of each of the bodies <NUM>, <NUM>, such as by way of a ring (e.g., a radiopaque marker band) that is attached to the distal end of the bodies. In another embodiment, one or more of bodies <NUM>, <NUM> can be formed at least in part by thermoplastic or other polymeric or composite material that is molded with a preformed bend therein. Such a pre-bent or pre-formed body <NUM>, <NUM> can then be loaded, for example, into main body <NUM>, wherein main body <NUM> maintains the bodies <NUM>, <NUM> in a straight orientation until they bodies <NUM>, <NUM> are advanced distally with respect to main body <NUM>, at which time they revert to their curved shape and regain at least some of their original curvature.

Main body <NUM> can simply be an overwrap or a sheath in some implementations that functions to maintain the bodies <NUM>, <NUM> in a parallel relationship and optionally maintains the bodies <NUM>, <NUM> in a relative orientation until the bodies <NUM>, <NUM> are advanced distally with respect to body <NUM>. In other implementations, body <NUM> can be more sophisticated such as a multi-lumen extrusion including a plurality of lumens for slidably containing bodies <NUM>, <NUM>, and other devices, as desired. In lieu of a main body <NUM> or overwrap, bodies <NUM>, <NUM> can alternatively be fused or adhered to each other, or be provided with an adjustable coupling that runs their lengths that permits relative slidability of bodies <NUM>, <NUM>. For example, body <NUM> can be provided with a rib along the majority of its length (e.g., except for the distal most <NUM>-<NUM>) having a "T"-shaped cross section, wherein the base of the T adjoins the body <NUM>, and body <NUM> can be provided with a "C"-shaped channel along its length that slidably receives the T-shaped rib.

If desired, each of the first elongate inner body <NUM> and second elongate inner body <NUM> can each define one or more lumens along their respective lengths. The lumen(s) can be used, for example, for passage of a further medical instrument such as a guidewire or viewing scope, for directing electrical conductors, and the like, and/or for passage of a steering wire along the length of body <NUM>, <NUM> terminating, for example, in a marker band at the distal end of body <NUM>, <NUM> that the steering wire attaches to. Other examples of suitable steering mechanisms can be found in <CIT>, and <CIT>. Either body <NUM>, <NUM> if equipped with such a passage can additionally or alternatively include a movable body (e.g., core wire, snare catheter, etc.) slidably disposed therein.

If the passage within body <NUM> includes a snare catheter (such as that described in <CIT>, which is annexed to <CIT>, as <CIT>), the snare catheter can be directed out of the distal end of body <NUM> to provide a landing or target zone for a guidewire that is directed through the distal end of body <NUM> (not shown). This permits a guidewire that traverses through the distal end of the body <NUM> to be captured by the snare catheter that extends outwardly from body <NUM>, thereby permitting the guidewire extending from the distal end of body <NUM> to be pulled into the distal end of body <NUM>, and advanced through the body <NUM> and externalized or otherwise directed out of the proximal end of body <NUM> (not shown).

If desired, the guidewire disposed in body <NUM> can include an electrically conductive core wire surrounded by a jacket made from dielectric/insulating material. The jacket can be removed from a portion of the core wire to expose a portion of the core wire. In a further embodiment, as illustrated in <FIG>, the guidewire can include a core wire that is in turn surrounded by a first insulating layer. As illustrated in <FIG>, the guidewire <NUM> can have an electrically conductive core wire <NUM> surrounded by a jacket <NUM> made from dielectric material, such as PTFE or other suitable material. The jacket can be stripped off on one side to create an exposed region <NUM> of the core wire <NUM>. The ends of the core wire <NUM> can likewise be exposed, and the wire can be bent in half so that the exposed core wire <NUM> faces itself. When the exposed ends <NUM> of the core wire <NUM> are then connected to a generator (not shown) in a bipolar arrangement in this case to cause current to pass through the core wire, in the exposed region of the core wire that is bent over, an electrical discharge, or arc, can develop that jumps across the gap (rather than the current passing only along the core wire) that can be used to help cut and/or burn through tissue by pulling the exposed wire through the tissue.

If desired, the guidewire can be provided with more than one conducting layer as embodiment <NUM> in <FIG>. Guidewire <NUM> has an exposed proximal end <NUM> connected to a distal tip (in this case in the shape of a metallic ball <NUM>, and an elongate core wire <NUM>. A first insulating layer <NUM> (made of a polymeric layer, for example), is disposed about the core wire <NUM> along its length, but leaving the tip <NUM> and proximal end <NUM> exposed. Proximal end <NUM> can be electrically coupled to a signal generator, and the current can pass, for example, through the distal tip <NUM> and follow a return path to a conductive path (not shown) through the patient's body (monopolar arrangement) to the electrical generator. This is a useful arrangement for cutting through tissue with the tip of the guidewire <NUM>. Guidewire <NUM> further includes a second electrical conductor, or conducting layer, <NUM>, is disposed at least partially about, or at least radially outwardly from, the first insulating layer <NUM>. The second electrical conductor/conducting layer <NUM>, in turn, can in turn be surrounded by an outer insulating layer <NUM>. The outer insulating layer can be removed to expose a portion of the second electrical conductor/conducting layer to define an exposed portion <NUM> of the second electrical conductor/conducting layer. As illustrated, portion <NUM> is facing laterally outwardly to permit a cut to be performed by moving the guidewire <NUM> laterally to the side, when a proximal end of the layer <NUM> is attached to a signal generator. Current then flows through the exposed portion <NUM> and through the tissue to a conductive pad that is attached to a return path of the signal generator. Conductive layer <NUM> can be a continuous layer, such as a tubular layer, or can be an interrupted layer, wherein a conductive path is nonetheless maintained from the exposed patch <NUM> to the proximal end of the conductive layer <NUM>.

Conductive layer <NUM> can be formed, for example, from a metallic tube, such as a hypotube, in turn be defined by a tubular body that defines at least one opening <NUM> therethrough. For example, the at least one opening can be spiral shaped (via laser cutting) and winds around the first insulating layer, resulting in the remaining conductive material also winding around the first insulating layer. Alternatively, the at least one opening and the tubular body define a plurality of articulating segments, similar to those defined in <CIT>, <CIT>, <CIT>, or <CIT>, and appended to <CIT>.

The disclosure also provides an electrosurgical system including a radio frequency power supply (such as that described in <CIT>, which is annexed to <CIT>) operably coupled to the electrically conductive core wire of the elongate catheters (and/or of the second conductors of catheters) disclosed herein. Thus, the radio frequency power supply can be operably (and selectively) coupled to the electrically conductive core wire and to the second electrical conductor, as desired. Similarly, the disclosure also provides an ultrasonic surgical system, such as an ultrasonic scalpel, including an ultrasonic power source, such as that disclosed in <CIT>.

In further embodiments, and with reference to <FIG>, the body (e.g., <NUM>) of the catheter can be configured so as to penetrate an anatomical structure, such as a heart valve leaflet <NUM>, prior to passing into the lumen of the first elongate inner body. Tip(s) <NUM> of the catheter can grip the leaflet and align the passages in the arms of the catheter to permit a guidewire (e.g., <NUM>, <NUM>) to pierce the leaflet and pass through the catheter arms. Piercing can be accomplished (preferably under imaging, such as fluoroscopy) with a sharpened tip and cuff connection, electrosurgical or ultrasonic cutting tip (e.g., <NUM>). Typically, the leaflet (e.g., <NUM>) is penetrated or pierced in a region that is near or in the annulus <NUM> of the valve leaflet, most preferably where the annulus transitions to the leaflet base. The disclosed embodiments can be used to perform the procedures described in the journal publications annexed to <CIT>). When an electrically exposed portion of the guide wire is in alignment with the leaflet, the ends of the catheter can be withdrawn partially, the electrical current can be turned on, and the exposed portion of the guidewire can be pulled through the leaflet, cutting the leaflet.

<FIG> presents an alternative embodiment of a grasping catheter <NUM> that can be used in place of a pair of catheters simply for grasping the edge of a leaflet <NUM>. The catheter <NUM> includes a tubular outer body <NUM> having a proximal end, a distal end and a longitudinal passage therethrough. An internal slidable gripping mechanism is slidably disposed within the lumen of outer body <NUM> that includes a proximal actuator or handle <NUM> that is connected to an elongate inner body <NUM> that separates at a bifurcation <NUM> into a first arm <NUM> and a second arm <NUM>, that in turn terminate in inwardly pointed gripping ends <NUM>, <NUM>. Arms <NUM>, <NUM> are biased away from each other, and can be urged together by withdrawing the arms and accompanying tips toward the distal end of the tubular member <NUM>. Accordingly, by controlling the relative placement of the inner mechanism and outer tube, the jaws formed by arms <NUM>, <NUM> and gripping ends <NUM>, <NUM> can be opened and closed. Catheter <NUM> can be used as a sub-catheter in any embodiment herein.

As a further example, the movable body (e.g., <NUM>, or a slidable device within a lumen defined by body <NUM>) can include a dart passer that is configured to advance a dart having a suture attached thereto out of the distal end of the second elongate inner body and into a receiving cuff disposed in the lumen of the first elongate inner body, in accordance with the teachings of <CIT>. For example, the receiving cuff can be disposed within a lumen defined in body <NUM> at is attached to a filament/suture that passes through the lumen of body <NUM> that can receive a dart attached to or resting on the distal end of a hypotube that is advanced through body <NUM>, wherein the dart has a trailing suture that passes through the body of the hypotube. After connecting the dart and cuff, the suture attached to the cuff or the suture attached to the dart can be advanced withdrawing the coupling from the patient, and leaving behind the looped suture.

In accordance with further aspects, the rotational position of the first elongate inner body <NUM> can be fixed with respect to the rotational position of the second elongate inner body <NUM>. Or, if desired, the rotational positions of each of body <NUM> and <NUM> can be controlled by a user at a control actuator/Luer lock at a proximal location of the catheter.

In accordance with further aspects, and as presented in <FIG>, the catheter can further include a third elongate inner body <NUM> having a proximal end and a distal end that is slidably disposed within the at least one elongate passage of the elongate tubular main body, the distal end of the third inner elongate body being biased (or otherwise configured, e.g. via steering wire) to curl away from the longitudinal axis in a proximal direction when the third elongate inner body is advanced distally with respect to the main body. If desired, the catheter can further include a fourth elongate inner body <NUM> having a proximal end and a distal end that is slidably disposed within the at least one elongate passage of the elongate tubular main body, and slidably disposed with respect to the third inner body. The distal end of the fourth inner elongate body <NUM> can be biased or otherwise configured to curl away from the longitudinal axis toward the proximally oriented distal end of the third elongate inner body <NUM> when the fourth elongate inner body is advanced distally with respect to the main body. Any suitable number of such inner bodies can be provided, depending on the procedure being performed.

As with the embodiment of <FIG>, the third elongate inner body <NUM> and fourth elongate inner body <NUM> can define a lumen along their lengths. The lumen of the fourth elongate inner body <NUM> can include a device as described elsewhere herein (guidewire, snare catheter) slidably disposed therein having a distal end that is configured to be received by the lumen of the third elongate inner body at the proximally facing distal end of the third elongate inner body.

Each of bodies <NUM>, <NUM>, <NUM>, <NUM>, <NUM> can be made from a variety of materials, including multilayer polymeric extrusions, such as those described in <CIT>or <CIT> to Fontirroche. Other structures are also possible, including single or multilayer tubes reinforced by braiding, such as metallic braiding material. Any of the catheters, manipulators, guidewires, or other catheters disclosed herein or portions thereof (e.g., portions <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) can be provided with regions of varying or stepped-down stiffness with length using any of the techniques set forth in <CIT>.

Preferably, the bodies <NUM>, <NUM>, <NUM>, <NUM> have a decreased stiffness along their length, particularly in their distal regions by adjusting the cross sectional dimensions of the material to impact stiffness and flexibility, while maintaining pushability, as well as the durometer of the material. Hardness/stiffness is described herein with reference to Shore hardness durometer ("D") values. Shore hardness is measured with an apparatus known as a Durometer and consequently is also known as "Durometer hardness". The hardness value is determined by the penetration of the Durometer indenter foot into the sample. The ASTM test method designation is ASTM D2240 <NUM>, an example of which is annexed to <CIT>. For example, a more proximal region of the catheter can have a durometer of about 72D, an intermediate portion of the catheter (the proximal most <NUM>-<NUM> of the last <NUM>, for example that typically traverses an aortic arch) can have a durometer of about 55D, and the distal <NUM>-<NUM> of the catheter can have a durometer of about 35D.

Any surface of various components of the system described herein or portions thereof can be provided with one or more suitable lubricious coatings to facilitate procedures by reduction of frictional forces. Such coatings can include, for example, hydrophobic materials such as PolyTetraFluoroEthylene ("PTFE") or silicone oil, or hydrophilic coatings such as Polyvinyl Pyrrolidone ("PVP"). Other coatings are also possible, including, echogenic materials, radiopaque materials and hydrogels, for example.

One or more actuators can be provided to actuate relative proximal and distal movement of bodies <NUM>, <NUM>, <NUM>, <NUM> with respect to main body <NUM>. Such actuators typically provide either two handles for push-pull actuation, or the actuator can be more exotic. For example, it is also possible to use other actuators as are known in the art, such as threaded rotating actuators similar to those for retractable sheaths as described in <CIT>and <CIT>.

With reference to <FIG> and <FIG>, the disclosure also provides a method that includes providing an electrosurgical system as described hereinabove, deploying the distal end of the catheter into a patient's vasculature to a target location proximate the patient's valve, deploying the first elongate inner body so that the distal end of the first elongate inner body curls around the edge of the patient's valve leaflet, deploying the second elongate inner body so that the distal end of the second elongate inner body bends toward the distal end of the first elongate inner body, directing the guidewire out of the distal end of the second elongate inner body, through the patient's valve leaflet near the valve annulus (such as where the annulus transitions to the base of the leaflet(, and into the lumen of the first elongate inner body, advancing the guidewire until the exposed portion of the core wire or second conductor is located in a gap defined between the distal end of the first elongate inner body and the distal end of the second elongate inner body that coincides with the valve leaflet, wherein the exposed portion of the core wire is facing in a proximal direction, energizing the power supply of the electrosurgical system, and advancing the exposed portion of the core wire or second conductor through at least a portion of the valve leaflet to effectuate a cut in the valve leaflet.

As described herein, when practicing the illustrative methods, the exposed portion of the core wire or second conductor can be advanced through the valve leaflet through a peripheral edge of the valve leaflet. In some implementations, the valve leaflet can be a mitral valve leaflet, such as a native or artificial/replacement anterior or posterior mitral valve leaflet, or a native or artificial/replacement tricuspid, pulmonary or aortic valve leaflet. It will be appreciated that the disclosed systems can be used with respect to any suitable native or artificial/replacement valve leaflet.

The disclosure also provides a robotic manipulator having a proximal end and a distal end that includes an elongate tubular arm having a proximal end, a distal end, and defining at least one elongate passage therethrough, the elongate tubular arm defining a longitudinal axis along its length. The manipulator further includes a first elongate inner body having a proximal end and a distal end that is slidably disposed within the at least one elongate passage of the elongate tubular arm, the distal end of the first inner elongate body being biased (or otherwise configured, such as pre-forming and/or steering wire) to curl away from the longitudinal axis in a proximal direction when the first elongate inner body is advanced distally with respect to the arm. The manipulator can further include a second elongate inner body having a proximal end and a distal end that is slidably disposed within the at least one elongate passage of the elongate tubular arm that can be slidably disposed with respect to the first inner body. The distal end of the second inner elongate body can be biased to curl away from the longitudinal axis toward the deployed proximally oriented distal end of the first elongate inner body when the second elongate inner body is advanced distally with respect to the arm.

At least one of the elongate tubular arm, first elongate inner body or second elongate inner body can be connected to an axial actuator, wherein the actuator is configured to advance the component to which it is connected along a direction parallel to the longitudinal axis. Moreover, at least one of the elongate tubular arm first elongate inner body or second elongate inner body can be connected to a rotational actuator, wherein the rotational actuator is configured to rotate one or more of the elongate tubular arm, first elongate inner body and second elongate inner body.

At least one of the first elongate inner body and second elongate inner body can include an end effector attached thereto configured to perform at least one of a cutting, grasping, irrigating, evacuating, viewing or suctioning function. If desired, the end effector can include one or more of an electrosurgical device, a blade, and an ultrasonic transducer.

The disclosure also provides implementations of a laparoscopic, urinary, gynecological, neurological, or orthopedic surgical procedure utilizing the catheters or robotic manipulators disclosed herein. The disclosed catheters/manipulators can also be used in any suitable minimally invasive procedure, or a percutaneous procedure.

For example, the percutaneous procedure can include utilizing one or more of the disclosed devices to access a patient's sinus passages. The devices can be used, for example, to remove one or more polyps, and can even be used to breach a thin bony layer within the sinuses to access the cranial cavity to perform a procedure inside the cranial cavity.

In other embodiments, the percutaneous procedures disclosed herein can include an ablation procedure, such as within the heart of a patient or elsewhere, as well as a cryoablation procedure. The disclosure also provides suitable handles and actuators (illustrated in the Appendix of <CIT>, for example) for controlling one or more of the first elongate inner body, second elongate inner body and elongate tubular main body.

In further accordance with the present disclosure, <FIG> illustrates a cross sectional view of an extruded main body portion <NUM> of a further embodiment of a catheter. The body includes an extrusion defining two offset channels <NUM>, <NUM>. A first channel <NUM> is illustrated as having a generally circular cross-section, and the second channel <NUM> that is parallel thereto is illustrated as having a cross-section that is circular with a scalloped portion removed in order to accommodate the channel with the circular cross section. The main body <NUM> can be made from any suitable polymeric material, such as those set forth herein. The main body can be formed from a multilayer polymeric extrusion with one or more reinforcement (e.g. layers of braiding) formed thereon or therein. The main body can be coated with any suitable coating or material to enhance its lubricity, as desired.

<FIG> presents a side view of the illustrative catheter of <FIG> including the main shaft <NUM> described above, provided with at least one braided layer. The catheter further includes a distal tubular segment extending distally from main shaft <NUM> that defines therein lumen <NUM> that is radially co-located with the first channel of the main body. For example, the distal tubular segment can be an extruded tube that extends the full length along the inside of the main body to a proximal end of the catheter. The distal tubular segment may similarly be braided if desired, may be pre-curved as described elsewhere herein and/or can be deflectable, for example, by providing a pull wire within the lumen of the distal segment, or within a co-extruded lumen of the distal segment (not specifically illustrated). A distal end of the pull wire (not shown) can be attached to a collar embedded within or on the distal tubular segment, as desired. As illustrated in <FIG>, the distal tubular segment and its associated channel that it surrounds can be used to act as a guidewire lumen, permitting the catheter to be used as an over the wire catheter, or for delivering a lower profile catheter therethrough, such as a snare catheter, as set forth in further detail below.

<FIG> illustrates an embodiment wherein the larger/major, e.g., non-circular, lumen defined in the main body can act as a delivery lumen for a catheter that can be steerable (e.g., by a steering wire) or that can have a curve preformed into it (e.g., by heating and bending the catheter if polymeric in composition) that the catheter can assume after it is advanced distally out of the distal end of the major lumen of the main body. As presented in <FIG>, the distal tubular segment can be provided with a further tubular member disposed thereon, or integrated therewith in a co-extrusion, that can act as a guidewire lumen to facilitate a rapid exchange ("RX") procedure with the guidewire rather than having the guidewire traverse the entire length of the catheter as in an over the wire ("OTW") procedure.

<FIG> presents the embodiment of <FIG>, but including a snare catheter <NUM> disposed through the minor lumen for effectuating capture, for example, of a guidewire in a mitral cerclage procedure as set forth in <CIT>. Further aspects of the snare catheter can be seen in that application, as well as in <CIT>. The present catheter can be used, for example, for such mitral cerclage procedures. For example, the snare catheter can be used to capture a guidewire while the major passage accommodates an articulating catheter as described hereinabove for grasping a cardiac valve leaflet, or other structure.

A further embodiment is presented in <FIG>, which illustrates an articulating catheter having two preformed bends that resume their bent shape when advanced distally from the main catheter. <FIG> illustrates a further possible cross section for the main catheter, wherein major and minor lumens <NUM>, <NUM> are presented, but two additional steering wire lumens <NUM> are presented. If desired, further steering wire lumens are presented that can be used for housing a pull wire that is attached at its distal end to a portion of the catheter (not shown), such as to a ring collar that is formed on or in the body of the catheter.

<FIG> display a further embodiment of a catheter in accordance with the disclosure (or aspects thereof) that includes a scoop on one of the articulating arms as presented. The scoop, or funnel, can help guide the other articulating arm into contact with it. If desired, permanent magnets can be added at the end of each articulating arm (not shown), or a winding around each end of the catheter can be made to form a solenoid on the end of each of the arms (not shown). When electrical current is run along the same helical direction through each solenoid, the created magnetic fields add to each other, and attract each other, causing the arms to move more closely together into contact. The force is directly proportional to the current that passes through the windings. Also illustrated is a push-pull actuator for relatively articulating each of the deployable limbs in the catheter. The disclosed catheter uses a toothed wheel, or gear, that rotates around an axle and engages a gear rack in a sliding track that in turn is attached to one of the articulating arms.

For purposes of illustration, and not limitation, <FIG> depict yet another embodiment of a catheter in accordance with the present disclosure.

<FIG> illustrates a further embodiment <NUM> of a catheter. The distal end <NUM> of catheter <NUM> is depicted to highlight its functionality. Catheter <NUM> also includes a proximal end and elongate body (not shown) having one or more actuators to manipulate the various sub-components of catheter <NUM> described in detail below. Catheter <NUM> is defined by an outer tubular member having a proximal end, a distal end <NUM>, and defines an elongate passage therethrough along its length. Elongate passage slidably accommodates an intermediate tubular member <NUM> therein having a proximal end (not shown), a distal end <NUM> and in turn also defining a passage along its length for slidably receiving a subassembly therein including at least one further catheter, tool or manipulator. As illustrated in <FIG>, a subassembly is provided slidably received within intermediate tubular member <NUM> that includes a central tubular member <NUM> having a proximal end, a distal end <NUM>, and defining a passage along its length, for example, for receiving a guidewire for guiding catheter <NUM> to a target location. As illustrated, central tubular member <NUM> is a straight member, but can be imparted with a curvature if desired. The subassembly further includes a second tubular member <NUM> having a proximal end (not shown), a distal end <NUM> and an elongate body defining a central lumen along its length. Second tubular member <NUM>, as illustrated, has a curvature imparted to it. Also provided are collapsible loops <NUM>, <NUM>, which may be made from any suitable material. The particular loops illustrated are formed from nitinol. Each loop is defined by a filament that can include a stress distribution loop (<NUM>, <NUM>) formed therein that traverses <NUM> degrees or more. Providing a stress distribution loop facilitates collapse of the loops <NUM>, <NUM> by distributing the bending stress over a longer effective length of wire. The material from which loops <NUM>, <NUM> is formed can extend to the proximal end of the catheter <NUM>, or may be secured in the distal ends of additional tubular members (not shown) that are slidably disposed in intermediate tubular member <NUM>. Loops can be made, for example, from shape memory material such as various nickel titanium alloys.

As illustrated, the subassembly within tubular member <NUM> can be both slidably and rotatably movable with respect to the outer tubular member of catheter <NUM>. If desired, each of the subcomponents <NUM>, <NUM>, <NUM> and <NUM> may be slidably and rotatably movable with respect to each other, and the main body of the catheter <NUM> as well as the intermediate tubular member <NUM>.

As illustrated in <FIG>, the embodiment <NUM> is illustrated in use with respect to the structure of a tricuspid valve. In use, after the distal end <NUM> of catheter <NUM> is advanced, for example, to a tricuspid valve, the subassembly housed within intermediate tubular member <NUM> is advanced distally out of distal end <NUM> of catheter <NUM>, and the distal end <NUM> of central tubular member <NUM> can be directed through the center of the tricuspid valve between the leaflets. Next, the two loops <NUM>, <NUM> are deployed and advanced under the leaflet against the center of each leaflet by the valve annulus. This permits tubular member <NUM> to be positioned at the center of the third leaflet by the annulus. At this time, any desired instrument, such as a cutting wire or piercing instrument can be advanced through the leaflet at its edge by the annulus, such as to advance a electrosurgical cutting wire through the leaflet, permitting the cutting wire to be dragged radially inwardly through the leaflet to cut the leaflet in half. In accordance with a further example, a suture can be anchored by subassembly component <NUM>. The suture can then be used as a guide rail for delivering a prosthesis to be implanted over the leaflet, with our without cutting it in half first. It will be appreciated that catheter <NUM> can be used in many different types of procedures and that these illustrations are only examples.

Claim 1:
An elongate catheter having a proximal end and a distal end comprising:
a) an elongate tubular main body (<NUM>) having a proximal end, a distal end, and defining at least one elongate passage therethrough, the elongate tubular main body defining a longitudinal axis along its length;
b) a first elongate inner body (<NUM>) having a proximal end and a distal end that is slidably disposed within the at least one elongate passage of the elongate tubular main body (<NUM>), the distal end of the first inner elongate body being configured to curl away from the longitudinal axis in a proximal direction when the first elongate inner body (<NUM>) is advanced distally with respect to the main body (<NUM>); and
c) a second elongate inner body (<NUM>) having a proximal end and a distal end that is slidably disposed within the at least one elongate passage of the elongate tubular main body (<NUM>), and slidably disposed with respect to the first inner body (<NUM>), the distal end of the second inner elongate body (<NUM>) being configured to curl away from the longitudinal axis toward the deployed proximally oriented distal end of the first elongate inner body (<NUM>) when the second elongate inner body is advanced distally with respect to the main body (<NUM>),
wherein:
the first elongate inner body (<NUM>) and second elongate inner body (<NUM>) each define a lumen along their respective lengths;
the lumen of the second elongate inner body (<NUM>) includes a movable body slidably disposed therein having a distal end, the movable body including a guidewire (<NUM>) having an electrically conductive core wire (<NUM>) surrounded by a jacket (<NUM>) made from dielectric material, wherein the jacket is removed from a portion of the core wire along one side of the core wire to create an exposed region (<NUM>) of the core wire; and
the distal end of the movable body is configured to penetrate a target tissue region prior to passing into the lumen of the first elongate inner body (<NUM>).