WO2000067834A1

WO2000067834A1 - Steerable catheter

Info

Publication number: WO2000067834A1
Application number: PCT/US2000/012817
Authority: WO
Inventors: Jeffrey J. Giba; Martyn Edward Leat; Philip J. D'a. Remedios; Matthew N. Mrdeza
Original assignee: Zynergy Cardiovascular, Inc.
Priority date: 1999-05-11
Filing date: 2000-05-11
Publication date: 2000-11-16
Also published as: AU4836200A

Abstract

A steerable catheter assembly (20) includes a flexible, elongated catheter body (30) having a proximal end (24), and a distal end (28), the distal end (28) of the catheter body (30) having at least one deflectable segment (36) having a distal end, and a proximal end (42). A support hub (32) is disposed at the proximal end (42) of the deflectable segment (36), and a deflection mechanism comprising an actuating assembly is disposed at the proximal end (24) of the catheter body (30). The actuating assembly is operatively attached to the deflectable segment (36), an actuator line (52) attached at its proximal end (54) to the actuating assembly, and attached at its distal end at the distal end of the deflectable segment (36). The actuator line (52) passes through the support hub (432). An actuator ribbon (60) is attached at its proximal end to the support hub (32), and is attached at its distal end at the distal end of the deflectable segment (36).

Description

STEERABLE CATHETER Technical Field

The present invention relates generally to catheters. More particularly, the present invention relates to a small, flexible, deflectable catheter which can be constructed to adjust or deflect in multiple planes and/or within individual segments or sections of the same catheter device to enhance the ability of the device utilized to acquire diagnostic data or to perform therapeutic applications including cardiovascular access, drug delivery, electrophysiology, and other applications where steering or access to a body cavity or vasculature is desired. Background of the Invention

Catheters have been utilized in medical treatment for many years.

Catheters are commonly used for such purposes as drug delivery, fluid removal, acquisition of diagnostic data, and the performance of therapeutic applications such as TMR, drug delivery, and the acquisition of

electrophysiology signals from the heart.

As the trend in the application of medicine has moved towards the use of less invasive techniques for performing certain procedures, the growing use of catheters and their specialized uses have increased the specificity and design of the catheters. As the use of catheters has increased, so too have the demands placed on catheter manufacturers and designers to provide catheters capable of meeting specific needs for a given procedure or to more easily and safely reach a specific location within the body such as the coronary sinus. These new demands have brought about the development of catheters which are more capable and more useful than their predecessors through the incoφoration of specific features designed to aid in their use, such as the steerable catheter.

There are many steerable or deflectable catheter systems and designs which are well known in the art. United States Patent No. 5,190,050 issued March 2, 1993 to Nitzche discloses a steerable catheter having a handle and a tube, the distal tip of which may be selectively curved by controllably moving one of three flat, sandwiched shims relative to the other by manipulation of a handle portion.

United States Patent No. 5,358,479 issued October 25, 1994 to Wilson discloses another steerable catheter with a handle and a center tube, the apparatus having a single elongated, substantially flat shim spring mounted within the tip of the catheter tube. The shim includes at least one transverse or lateral twist which causes the tip of the catheter tube to assume a desired curvature. United States Patent No. 5,368,564 issued November 29, 1994 to

Savage discloses a catheter having a steerable tip which includes multiple wires embedded in a catheter wall to pull a distal portion of the catheter tip. However, Savage does not teach a steering mechanism capable of deflecting simultaneously in more than one plane, the wires have limited flexibility, and, since the wires are affixed in the walls, the device cannot translate movement in segments or predefined planes or directions.

United States Patent No. 5,545,200 issued August 13, 1996 to West et al. discloses a steerable electrophysiology catheter having a center core torquing wire centered about a spring shaft housing. By twisting with a torquing ring, the tip can be moved in a rotating direction. However, West et al. do not teach a catheter having the ability to deflect in multiple planes and the West et al. design also suffers from several drawbacks including that rotation of the bent section is difficult to control as it introduces whipping dynamics. Additionally, due to the complexity of the West et al. catheter design, the catheter internal components do not permit size reduction, flexibility, and additional space requirements.

United States Patent No. 5,431,168 issued July 11, 1995 to Webster, Jr. teaches a steerable open-lumen catheter which utilizes pull wires within multi- lumens which are affixed at both the distal tip and the proximal handle.

Webster, Jr. teaches the use of a coil for steering or deflecting the catheter tip. Because the Webster, Jr. catheter utilizes both springs and wires disposed in separate lumens, valuable space is taken up which limits the size to which the catheter assembly can be reduced. Additionally, the use of multi-lumens to isolate the deflecting coils reduces the overall flexibility of the catheter due to the incorporation of the septal walls of each lumen. This design also decreases the sensitivity and ease of steering of the catheter due to the same septal stiffening. Additionally, Webster, Jr. does not teach the ability to deflect in two different planes at the same time, nor does it teach the ability to vary the location of catheter deflection.

United States Patent No. 5,364,351 issued November 15, 1994 to Heinzelman et al, WO 94/26347, and WO 91/11213 disclose catheter steering mechanisms which utilize a two wire, two sided pull system with a spring core and stacking shims. However, the use of a spring core and stacking shims takes up a great deal of space within the catheter and, therefore, does not permit easy reduction in the size of the catheter assembly.

United States Patent No. 5,478,330 issued December 26, 1995 to Imran et al. teaches a steerable catheter with adjustable bend location and/or radius which utilizes a pull wire with a specified material stiffness and a slidable mandrel to adjust the bend location while the catheter is in use thus giving the ability to deflect in different locations upon selection within the same plane. However, this design takes up considerable space within the internal lumen of the catheter which does not allow for device reduction and further reduces the flexibility of the device.

WO 93/20877 teaches a steerable electrode catheter having a spring or coil axially loaded with multi-pull wires for steering. The device is a multi- lumen catheter with a bend torque transmission handle. The lumens and pull wires are radially offset to provide for deflection in several planes. The device includes a torque ring to assist in torque transmission from the handle.

However, the use of multi-lumens in this device restricts the flexibility of the catheter and the mechanism of steering by torquing the handle which pulls on the control wires is cumbersome and provides difficulty in maintaining a good tactile feel and deflection control. United States Patent No. 5,876,373 issued March 2, 1999 to Giba et al. discloses an elongated steerable catheter having at least one center tube with a hollow passageway for guiding a laser delivery means or other functional device to a selected location. The steerable catheter has a handle portion at its proximal end and a controllably deflectable end portion at its distal end. The elongated center tube has a distal end, in the region where a curvature is to be formed, and a shim anchor sleeve is slidably disposed over the center tube. The shim anchor sleeve is attached to the inside wall of the outer jacket and is coupled to the distal end of the center tube with a bendable shim member which extends between the distal tip of the steerable catheter and the sleeve over the center tube. Opposite the shim is a guide for a pull cable which is attached to the distal end of the steerable catheter and extends through the guide to the handle. However, the Giba et al. device does not teach the ability to have multiple deflecting segments, nor does it allow for the reduction in size of the catheter assembly.

It can be seen from the descriptions of the prior art set forth above that steerable catheter assemblies are well known in the art. However, there remains a need in the art for a steerable catheter which allows for the steering or deflection of various catheter sections by stacking or segmenting deflection points for multi-deflection and planar variations within a single catheter which also provides a compact, flexible and simplified catheter assembly.

Summary of the Invention A steerable catheter assembly includes a flexible, elongated catheter body having a proximal end and a distal end, the distal end of the catheter body having at least one deflectable segment having a distal end and a proximal end.

A support hub is disposed at the proximal end of the deflectable segment and a deflection mechanism comprising an actuating assembly is disposed at the proximal end of the catheter body. The actuating assembly is operatively attached to the deflectable segment, and an actuator line attached at its proximal end to the actuating assembly and attached at its distal end at the distal end of the deflectable segment. The actuator line passes through the support hub. An actuator ribbon is attached at its proximal end to the support hub and is attached at its distal end at the distal end of the deflectable segment whereby when the actuator line is placed under tension, the deflectable segment is deflected about the support hub and when the tension applied to the actuator line is released, the deflectable segment returns to its original position. Brief Description of the Drawings Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

Figure 1 is a perspective view of a steerable catheter assembly constructed in accordance with the present invention; Figure 2 is a side cross-sectional view of a distal portion of the catheter

assembly of Figure 1;

Figure 3 is a cross-sectional view taken along lines 3-3 of Figure 2; Figure 4 is an exploded perspective view of an alternative embodiment

of the present invention; Figure 5 is a detailed view of detail 5 of Figure 4;

Figure 6 is a cross-sectional view taken along line 6-6 of Figure 2; Figure 7 is a cross-sectional view taken along line 7-7 of Figure 3; Figure 8 is a plan view of an actuator ribbon of the present invention; Figure 8A is a side view of an alternative embodiment of the actuator ribbon;

Figure 9 is a perspective view of an alternative embodiment of the present invention; Figure 10 is a perspective view of a further alternative embodiment of the present invention;

Figure 11 is a cross-sectional view taken along line 11-11 of Figure 10; Figure 12 is an exploded perspective view of an actuator handle in accordance with the present invention; Figure 13 is an exploded perspective view of an alternative cable fixation mechanism in accordance with the present invention;

Figure 14 is a side cross-sectional view of an alternative embodiment of an actuator handle in accordance with the present invention;

Figure 15 is a plan view of an alternative embodiment of a cable retention element; and

Figure 16 is an enlarged region of detail 16 of Figure 15.

Detailed Description of the Invention Referring to Figure 1, a representative view of a steerable catheter assembly of the present invention is generally shown at 20 inserted into a subject 21. The steerable catheter assembly 20 has an actuator handle assembly 22 at its proximal end 24 and a controllably deflectable end portion 26 at its distal end 28. A central catheter body 30 substantially extends between the actuator handle assembly 22 and the distal end 28. Referring specifically to Figure 2, an enlarged cutaway view illustrating the junction of a support hub 32 and a first 34 and a second 36 catheter body sections. Referring to Figures 1 and 2, the catheter body 30 can be comprised of at least two sections. Generally, the sections are defined by the placement of the support hub 32 which is disposed at or on an interface edge 38 of each section 34,36 of the catheter body 30. Typically, those sections 36 designated as steerable or deflectable sections are made of a material which is more flexible and resilient than the material which comprises the sections 34 of the catheter body 30 which are not designed to specifically deflect or to be steered. The steerable or deflectable section 36 is preferably constructed of an extruded polymer such as a polyurethane. The steerable or deflectable section 36 preferably has a softer durometer than the non-steerable section 34. A softer durometer material which can be used for the deflectable section 36 can include polyurethane and PEBAX. However, any suitable material capable of bending or deflecting can be used. The non-steerable or non-deflectable sections 34 are generally constructed of a harder durometer or stiffer material than the material used for the sections 36 such as nylon, PEBAX, and PEB AX- NYLON. These materials can also include braided tubing, multi-layer composite tubing, etc. Braided materials can include nickel-titanium, tungsten, stainless steel and any biocompatible material which can be braided. The support hub 32 transfers columnar force for deflection through the various catheter body sections. The support hub also permits stacking or segmenting of deflection points for multiple deflections and planar variations in one catheter. The first section 34 is the non-deflecting section and the second section 36 is the deflecting section. The support hub 32 has a substantially tubular portion 40 which is received and retained in the second or deflectable section 36 of the catheter body 30 whereby a proximal end 42 of the flexible section 36 is disposed adjacent to and abuts a ledge portion 44 of the support hub 32. The support hub 32 also includes a substantially tubular portion 46 disposed on the opposite end thereof which is received and retained in a distal end 48 of the first non-deflecting section 36 and is disposed adjacent to and in abutment with the ledge portion 44 of the support hub 32.

Referring now to Figure 3, the support hub 32 is shown in cross-section and includes a cable guide/mounting aperture 50 for receiving an actuator cable

52 therein. Referring to Figures 2 and 3, the cable guide/mounting aperture 50 allows the actuator cable 52 which is affixed at its proximal end 54 within the actuator handle 22 to slidingly pass through the guide aperture 50 to the distal end 28 of the catheter assembly 20 where it is affixed within a distal tip 56 partially disposed within the flexible section 36 of the catheter body 30. The support hub 32 also includes a substantially rectangular opening 58 therein which is designed to receive and retain an actuator ribbon 60 therein. In this embodiment, the actuator ribbon 60 extends between the support hub 32 and the distal tip 56 of the steerable section 36 of the assembly 20. In a preferred embodiment, the actuator ribbon 60 is constructed of a Ni-Ti alloy or any super-elastic alloy. Both the actuator cable 52 and the actuator ribbon 60 are preferably affixed to the distal tip 56 by means such as by laser welding or other suitable techniques known to those skilled in the art and can depend on the materials used for the components being joined. The distal tip 56 is preferably made of metal and is contoured and/or polished to minimize any adverse effect, such as trauma, caused by motion of the distal tip 56 through a body lumen, cavity, or opening, or by loss of maneuverability and control thereof. The distal tip 56 can be made of any biocompatible material including metals such as platinum, metal alloys such as Ni-Ti and stainless steel, coated metals, and/or polymeric materials depending on the desired function and application.

The support hub 32 also includes a more centrally disposed opening or passage 62 which provides access to a central lumen or lumens 64 coextensively disposed the length of the catheter body 30. This opening 62 provides a passage for wires, lumens, tubing, etc., which may run the length of the lumen 64 of the catheter body 30. For example, referring to Figures 4 and 5, electrical signals could be transmitted either to or from a sensor 66 disposed at the distal tip 56 through the catheter body 30 via a wire 68 to a receiving device (not shown) disposed either in the actuator handle 22 or which is remotely located but accessible through the actuator handle 22.

Referring to Figure 6, a cross-sectional view taken through the distal tip 56 is shown. This Figure illustrates the fixation and orientation of the actuator cable 52 and the actuator ribbon 60 within the distal tip 56. Referring again to Figures 2, 3, 7, and 8, the actuator ribbon 60 extends through the substantially rectangular opening 58 of the support hub 32 and is secured therein by resiliently displaceable feet 70 disposed at one end 72 thereof. The feet 70 are deflected inwardly upon insertion of the end 72 of the actuator ribbon 60 into the opening 58 of the support hub 32 and resiliently deflect outwardly when the end 72 of the actuator ribbon 60 is advanced beyond an end 74 of the support hub 32 thereby retaining the actuator ribbon 60 therein. The actuator ribbon 60 defines a plane in which the deflectable section 36 can be deflected through upon the application of a force through the actuator cable 52. The actuator ribbon 60 will cause the deflectable section 36 to return to its non-deflected condition with spring-like action upon the release of the deforming force. Referring to Figure 8, a tang 76 disposed at the opposite end 78 of the actuator ribbon 60 serves to anchor and orient the actuator ribbon 60, prior to welding, to the distal tip 56. The rigid or non-deflectable section 34 of the catheter body 30 is preferably constructed of a tubular material such as, but not limited to, polyurethane or other suitable polymeric material which will resist collapse during bending and twisting, and which will resist collapse by internal forces.

Both the deflectable portion 36 of the catheter body 30 and/or the actuator ribbon 60 can preferably be made, at least partially, or otherwise comprised of, a super-elastic material which can be given a selected shape. Other suitable materials include platinum, spring steel, stainless steel, shape memory or super-elastic/shape memory alloys. Once a super-elastic material has been shaped, it has a memory for that shape. Upon deformation from the preformed shape, the material will tend to independently return to its preformed shape with spring-like action. Thus, the deflectable portion 36 of the steerable catheter assembly 20 can be temporarily deformed or otherwise curved so as to steer and position the deflectable portion 36 of the steerable catheter assembly 20 through vasculature or other body opening. In the case of shape memory materials, a "memory" for a preformed shape can be temperature set into the deflectable portion 36 of the steerable catheter assembly 20. The steerable catheter assembly 20 can be straightened or deformed and extended through the vasculature or body opening. Once the steerable catheter assembly 20 is in position, memory recall of the original preformed shape can be produced by any of a number of ways. These include heating using electrically resistive material, electrically sensitive material, radio frequencies, circulating heated fluid, laser or light energy sources, etc.

The actuator ribbon 60 can also be preformed having a predetermined size and/or shape or multiples thereof, i.e., twisted, thicker in particular regions as shown in Figure 8A which can provide multiple deflection locations, to alter the bending moment of the actuator ribbon 60. By pre-shaping super-elastic material or by varying the deflection locations along the same actuator ribbon 60 with thin or "wasted" joints, the catheter assembly 20 can be made to deflect in predetermined planes and/or segments within the same deflection actuation.

The super-elastic material can be preshaped by techniques including annealing.

The actuator ribbon 60 is supported within the support hub 32 such that the actuator ribbon 60 bends against the support hub 32, not against the catheter body 30, at the bending point establishing one deflection point. The orientation of the actuator ribbon 60 and the actuator cable 52 is such that the actuator ribbon 60 and the actuator cable 52 are disposed approximately 180 degrees from each other. That is, as shown in Figures 2 and 3, a face 80 of the rectangular cross section of the actuator ribbon 60 faces the actuator cable 52. As will be understood, increasing the tension on the actuator cable 52 by retraction thereof will cause deflection of the distal end 28 and of the deflectable portion 36 of the catheter body 30 about the deflection point defined or caused by the support hub 32 in a direction essentially out of/into a position peφendicular to the plane of the actuator ribbon 60. Continued retraction of the actuator cable 52 will cause continued deflection of the distal portion 28 of the steerable catheter assembly 20, with useful ranges of deflection between about 0 and about 180 degrees (U-shaped) to about 270 degrees (pig-tail shaped), or more or less depending upon construction and length of pull.

The actuator cable 52 is preferably comprised of a multi-stranded or braided cable of a high tensile strength material such as tungsten. By utilizing a smaller diameter, stranded or braided length of cable or wire, greater flexibility can be achieved with an overall reduction in the diameter of the actuator cable 52. Furthermore, the use of a high tensile material, such as tungsten, allows a smooth finish to be disposed upon the actuator cable 52 making coatings for friction reduction unnecessary. Additionally, the increased tensile force for a smaller diameter allows for greater deflection capability with reduced dimensional characteristics. The mechanical stiffness (elastic modulus) of the materials comprising the deflectable section 36 of the catheter body 30 controls or limits the amount of movement of the distal portion 28. By creating a deflectable section 36 having a differential material stiffness across a diametric cross-section, a hinge or deflection point can be created. The axial length of the materials will control the minimum radii of curvature of the hinge. The deflectable section 36 can have variable radii curvature as a result of the material used for the actuator ribbon 60 or the material used for the deflectable section 36, itself.

Additionally, as described above, by utilizing materials with varying the shape, size, and/or the materials utilized for the actuator ribbon 60, the catheter assembly 20 can be designed to bend at a predetermined or selected point within the deflectable portion 36 of the catheter body 30. Such a point can be immediately adjacent the distal tip 56, between the distal tip 56 and the support hub 32, and/or adjacent the support hub 32 itself. The distal tip 56 of the deflectable section 36 can be moved in three-dimensions thereby rendering the catheter assembly 20 of the present invention highly suitable for a variety of procedures and operations.

The steerable catheter assembly 20 can be constructed so as to deflect in more than one direction or plane. As shown in Figures 1-3, the catheter assembly 20 utilizes only a single actuator cable 52, a single actuator ribbon

60, and a single support hub 32 to cause deflection in one direction and one plane. However, referring to Figure 9, an alternative embodiment of the steerable catheter assembly 20 of the present invention is shown. It will be understood that structural elements with like reference numerals, as described herein with reference to the drawings, are identical or similar to each other. A steerable catheter assembly 20 is shown which is capable of movement from two spaced apart locations on the catheter body 30. The catheter assembly 20 includes a first support hub 32 defining a first deflection point 90 and a second support hub 32' defining a second deflection point 92 which, as shown, is approximately 180 degrees from the direction of deflection defined by the first support hub 32. It should be pointed out that the deflection points 90, 92 do not necessarily have to be offset from one another by 180 degrees, and that the amount of offset can be varied to any point within 0 and 180 degrees. In this embodiment, a first actuator cable 52 extends from the actuator handle 22 through the second support hub 32', through the first support hub 32 and is attached to the distal tip 56 by means as described above. A first actuator ribbon 60 extends from the first support hub 32 to the distal tip 56 similar to that described above. A second actuator cable 52' extends from the actuator handle 22 through the second support hub 32' and further extends to the first support hub 32 where it is fixedly attached thereto. A second actuator ribbon 60' extends between the second support hub 32' and the first support hub 32 and is fixed to each support hub 32, 32' by means of deflectable feet 70 disposed at both ends thereof. In this embodiment, as will be understood, increasing the tension in the first actuator cable 52 by retraction thereof will cause deflection of the distal tip 56 about the first deflection point 90 defined by the first support hub 32. Increasing the tension on the second actuator cable 52' by retraction thereof will cause deflection of the distal tip 56 about the second deflection point 92 in the same plane as the deflection about the first deflection point 90 but in the opposite direction and from a different deflection point. Thus, greater control of the catheter assembly 20 is achieved since it can be steered or deflected at multiple sites along its length. In order to be able to deflect the catheter assembly 20 at multiple sites along its length, longitudinal columnar force must be maintained between the deflection points. This can be achieved by offsetting the planes of deflection by ninety degrees, varying the stiffness of the catheter body 30 such that the more distal portions of the catheter body are less stiff than the more proximal portions of the catheter body 30. That is, as one moves from the distal portion of the catheter body 20 toward the proximal portion, the stiffness of the catheter body increases. It should be pointed out that the number and/or the orientation of the actuator ribbons and the actuator cables can be varied to produce movement in different planes and/or in different directions in any of a number of combinations.

It is important to point out that while embodiments utilizing one and two support hubs 32, respectively, are shown and described above, the present invention also contemplates embodiments which utilize more than two support hubs 32 therein in order to construct steerable catheter assemblies which are capable of deflection in a multitude of selected or desired planes and directions.

Referring to Figures 10 and 11, a further embodiment of the steerable catheter assembly 20 of the present invention is shown. In this embodiment, a single support hub 32 is utilized in combination with a single actuator ribbon 60 centrally disposed within a portion of the catheter body 30 and affixed to the distal tip 56. A first 52 and a second 52" actuator cable are disposed opposite to each flat face of the actuator ribbon 60 as specifically shown in Figure 11. In this embodiment, retraction of the first actuator cable 52 will cause deflection of the distal tip 56 in a given plane in a first direction. Retraction of the second cable 52" will cause deflection of the distal tip 56 in the same plane in a direction opposite to that generated by the first actuator cable 52. Referring now to Figure 12, an exploded view of the actuator handle 22 of the present invention is shown. The actuator handle 22 includes a housing 94 comprised of a first section 96 and a second section 98. The catheter body 30 is received in a first end 100 of a strain relief 102 attached to the housing 94. The catheter body 30 extends into the actuator housing 94 where it is typically sealed-off. The actuator cable or cables 52 then extends through a bore 104 disposed in a thumb wheel 106 having reversible threads 108 disposed thereabout. The thumb wheel 106 is held in place by ribs 110 disposed in the first and second halves of the housing 94. A portion of the thumb wheel 112 extends through openings 114 disposed in the first 96 and the second 98 halves of the housing 94 to provide access to a user of the steerable catheter assembly 20. The actuator cable 52 then extends through a continuous bore 116 disposed through a cable actuator slide 118. The movement of the cable actuator slide 118 is controlled within the housing 94 by control stops 120 disposed on the interior of the housing section 96, 98 allowing the cable actuator slide 118 to move in a linear fashion. The end 122 of the actuator cable 52 is then fixed to a cable attachment slot 124 having a cable retention element 126 disposed thereon to receive and retain the end 122 of the actuator cable 52 therein. The cable attachment slot 124 is disposed about an externally threaded portion 128 of the cable actuator slide 118. A first tensioning nut 130 is disposed on the threaded portion 128 of the cable actuator slide 118 between a shoulder portion 132 of the cable actuator slide 118 and the cable attachment element 124 which is disposed between a second nut 130'. The tensioning nut 130 provides a mechanism to place the actuator cable 52 under tension by rotating the tensioning nut 130, 130' about the threaded portion 128 of the cable actuator slide 118 causing the cable attachment element 124 to be retracted or extended as needed to properly tension the actuator cable 52.

The threaded portion 108 of the thumb wheel 106 threadingly engages the threaded bore 116 of the cable actuator slide 118 and thereby causes the cable actuator slide 118 to be longitudinally displaced within the housing 94 along an axis defined by the actuator cable 52. By causing the cable actuator slide 118 to move in a direction opposite to the distal tip 56 of the catheter assembly 20, tension in the actuator cable 52 is increased by retraction thereof causing the distal tip 56 to deflect. If the thumb wheel 106 is rotated in the opposite direction, tension is removed from the actuator cable 52 thereby allowing the deflected portions of the catheter assembly 20 to return to a non- deflected condition.

The actuator handle assembly 22 provides for a simplified slide pull combination while also incoφorating a built-in friction lock with reversible threads that pull and permit recovery. Friction is used to hold the deflection without a locking mechanism and also provides controlled deflection speed.

As shown in Figure 4, cables or wires 68 connected to elements disposed on the distal tip 56, such as sensors 66 or electrodes for electrophysiology monitoring, can also exit from the bore 116 of the actuator slide 118 where they can be connected to monitoring devices such as deflection sensors or electrophysiology monitoring equipment. Additionally, a lumen 64 or lumens could also exit the actuator assembly 22 at this point where they could be connected to, for example, a drug delivery device or a device for sampling fluid therefrom. A port or opening (not shown) in fluid communication with the lumen 64 can also be disposed at a distal point or points of the catheter body 30 to allow for drug delivery or other functions. The housing 94 further includes an electrical cable 134 which is connected to the housing 94.

Referring to Figure 13, an alternative embodiment for actuation of the assembly 20 is shown. In this embodiment, a first actuator cable 52 exits from the actuator slide 118 and is disposed about a pulley bar 136 affixed within the housing 94. A second actuator cable 52' is attached to the cable attachment slot 124. The pulley bar 136 is made of a strong material having a low coefficient of friction and preferably lubricious properties to allow the cable 52 to more easily move thereover. The end 122 of the actuator cable 52 is then affixed to the actuator slide 118 by the cable attachment element 124 and is secured utilizing a first 130 and a second 130' tensioning nut. In this embodiment, when the thumb screw (not shown) is rotated, the same linear movement causes bi-directional deflection of the deflectable portions of the catheter assembly 20.

Referring to Figure 15, an alternative cable attachment element 124' is shown. The cable attachment slot 124' is preferably utilized in embodiments wherein at least two control cables 52 are utilized. That is, a first cable 52 can be disposed within an aperture or throughbore 138 disposed in a finger-like extension 140 which is affixed at a base portion 142 to a generally ring-like structure 144 which defines the periphery of the cable attachment slot 124'. Referring to Figure 16, an enlarged view of the detail labeled 15 of Figure 15 better illustrates this embodiment of the cable retention element 124'. The extension 140 also includes a nonattached end 146. In a two cable system similar to that disclosed in Figure 13, a first cable 52 would be disposed within the aperture 138 and then would exit from the aperture 138 and be disposed about the pulley bar 136 disposed within the housing 94. The end of the cable 52 would then be receivingly retained within a first retention slot or element

148 of the retention element 126'. A second cable 52' could be affixed within a second retention slot 150 of the retention element 126' to be retained therein.

In a multi-cable embodiment, the actuator handle assembly 22 can include a first 106 and a second 106' thumb wheel as shown in Figure 14, wherein the first thumb wheel 106 is disposed inside of the second thumb wheel 106' and extends past the first actuator slide 118 to operatingly engage a second actuator slide 118'. Thus, the same actuator handle assembly 22 can be used to actuate a first actuator cable 52 and a second actuator cable 52' and allow the steerable catheter assembly 20 to be deflected in two different planes and/or two different directions using a single control device.

The steerable catheter assembly 20 of the present invention can be used for the access of coronary vessels, heart chambers, or vascular access where fine, minute deflection and control is required. Additionally, the steerable catheter assembly 20 may be used as a steerable angiographic catheter, a steerable guide catheter, a drug delivery catheter, a percutaneous transmyocardial revascularization (TMR) catheter or for any application where multi-plane and multi-segmented deflection control would allow the user more precise access to a region, location, vessel, or chamber for diagnostic and/or therapeutic use. The present invention allows the design or preprogramming of different deflecting configurations by adjusting the location of the support hub(s) and/or the actuator ribbon location or characteristics.

Any patents or publications mentioned in the specification are indicative of the levels of those skilled in the art to which the invention pertains. These patents and publications are herein incoφorated by reference to the same extent as if each individual publication was specifically and individually indicated to be incoφorated by reference.

In view of the teaching presented herein, other modifications and variations of the present invention will readily be apparent to those of skill in the art. The discussion and description are illustrative of some embodiments of the present invention, but are not meant to be limitations on the practice thereof. It is the following claims, including all equivalents, which define the

scope of the invention.

Claims

Claims 1. A steerable catheter assembly, said catheter assembly comprising:

a flexible, elongated catheter body having a proximal end and a distal end, said distal end of said catheter body having at least one deflectable segment having a distal end and a proximal end; a first support hub disposed at said proximal end of said deflectable segment; a deflection mechanism comprising an actuating assembly disposed at the proximal end of said catheter body, said actuating assembly operatively attached to said deflectable segment; a first actuator line attached at its proximal end to said actuating assembly and attached at its distal end at said distal end of said deflectable segment, said actuator line passing through said support hub; a first actuator ribbon attached at its proximal end to said support hub and attached at its distal end at said distal end of said deflectable segment; and whereby when said actuator line is placed under tension, said deflectable segment is deflected relative to said support hub and when the tension applied to said actuator line is released, said deflectable segment returns to its original position.

2. A catheter assembly as set forth in claim 1, wherein said support hub includes a first substantially tubular portion which is received within said deflectable segment.

3. A catheter assembly as set forth in claim 2, wherein said support hub includes a second substantially tubular portion disposed on the end opposite said first substantially tubular portion, said second substantially tubular portion being received within a non-deflectable segment of said catheter body.

4. A catheter assembly as set forth in claim 1, wherein said support hub comprises an aperture for receiving said actuator line therein.

5. A catheter assembly as set forth in claim 1 further comprising a tip element, said tip element being disposed at the distal end of said deflectable segment.

6. A catheter assembly as set forth in claim 1, wherein said support hub further comprises a substantially centrally disposed opening therethrough.

7. A catheter assembly as set forth in claim 1, wherein said actuator ribbon includes resiliently displaceable feet disposed on at least one end thereof, said resiliently displaceable feet being lockingly received within said support hub.

8. A catheter assembly as set forth in claim 1, wherein said actuator ribbon defines a plane in which said deflectable segment deflects.

9. A catheter assembly as set forth in claim 1, wherein said actuator ribbon comprises a super-elastic material.

10. A catheter assembly as set forth in claim 1, wherein said actuator ribbon comprises a shape memory material.

11. A catheter assembly as set forth in claim 1, wherein said actuator ribbon comprises stainless steel, spring steel, platinum, or combinations thereof.

12. A catheter assembly as set forth in claim 1, wherein said actuator ribbon includes two flat faces, said actuator line disposed within said catheter body substantially adjacent to at least one of said flat faces, whereby when said actuator ribbon is caused to bend relative to said support hub, said deflectable segment bends in a plane defined by said face of said actuator ribbon.

13. A catheter assembly as set forth in claim 12, wherein said actuator ribbon and said actuator line are disposed approximately 180 degrees from each other.

14. A catheter assembly as set forth in claim 1 further comprising a second support hub disposed on said deflectable segment axially spaced apart from said first support hub; a second actuator ribbon disposed between said first support hub and said second support hub; and a second actuator line affixed at its proximal end to said actuating assembly and affixed at its distal end to said first support hub, thereby defining a first deflection point about said first support hub and a second deflection point about said second support hub.

15. A catheter assembly as set forth in claim 14, wherein said first deflection point and said second deflection point are in different planes with respect to each other.

16. A catheter assembly as set forth in claim 14, wherein said second actuator ribbon has two flat faces, said faces of said second actuator ribbon being offset from 0 to 180 degrees from said faces of said first actuator

ribbon.

17. The steerable catheter of claim 1, wherein at least portions of the catheter body comprise shape memory materials.

18. The steerable catheter of claim 1, wherein the catheter body comprises a distal deflectable end portion and a proximal steerable portion.

19. The steerable catheter of claim 1, wherein said actuator line is

comprised of braided tungsten wire.