WO2010119445A1

WO2010119445A1 - Guide wire for stabilizing a catheter with respect to target tissue

Info

Publication number: WO2010119445A1
Application number: PCT/IL2010/000304
Authority: WO
Inventors: Ran Carmeli; Eyal Teichman
Original assignee: Assis Medical Ltd.
Priority date: 2009-04-16
Filing date: 2010-04-15
Publication date: 2010-10-21

Abstract

A guide wire being capable of guiding a catheter along a vessel is provided. The guide wire includes a distal portion which is positionable within a target site and includes a deployable pre-shaped structure capable of occupying a volume. In one embodiment, the guide wire is configured for use in positioning a catheter used for delivering a prosthetic heart valve.

Description

GUIDE WIRE FOR STABILIZING A CATHETER WITH RESPECT TO TARGET

TISSUE

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to a guide wire for guiding a catheter to a target tissue such as a heart valve. The guide wire of the present invention is configured for identifying the target tissue while also stabilizing the catheter and any device delivered therefrom with respect to the target tissue.

Heart valve abnormalities such as valvular insufficiency and valvular stenosis can result in insufficient opening or closure of a heart valve.

Valvular insufficiency is a common cardiac abnormality where the valve leaflets do not completely close. This allows regurgitation (i.e., backward leakage of blood at a heart valve). Such regurgitation requires the heart to pump both the regular volume of blood and the blood that has regurgitated. Such added workload can eventually result in heart failure.

Valvular stenosis or calcification is a calcium buildup in the valve which impedes proper valve leaflet movement and can severely limit opening of the valve. Traditionally, heart valve abnormalities are treated via open heart surgery, however, in individuals whose heart function is too severely compromised to withstand surgery; percutaneous approaches for treating heart valve disease have been developed.

Percutaneous valvotomy (also called valvuloplasty) is typically performed to treat mitral valve and pulmonic valve stenosis; in some patients it may also be performed to treat stenosis of the aortic valve.

Although valvuloplasty is effective in treatment of mitral and pulmonic valve stenosis, it is not considered effective in treatment of severe symptomatic aortic stenosis; studies have shown that valve replacement is the only viable option for effective treatment. The need for a valve replacement solution combined with the need for minimally invasive surgery has led to the development of percutaneous valve replacement approaches.

Percutaneous valve replacement (PVR) is performed by placing a catheter over a guide wire through the femoral artery (in the groin) or through a radial artery and guiding it into the chambers of the heart. A compressed tissue heart valve is placed on the balloon-mounted catheter and is positioned directly over the diseased aortic valve. Once in position, the balloon is inflated to secure the valve in place.

At present, work on percutaneous valve replacement is proceeding at a pace that reflects intensifying professional and commercial interest and although numerous percutaneous valve replacement approaches are known in the prior art, the present inventors believe that there remains a need for a percutaneous valve positioning system which can be used by a physician to locate the valve and stabilize a valvuloplasty/delivery catheter thereagainst.

SUMMARY QF THE INVENTION

According to one aspect of the present invention there is provided a guide wire being capable of guiding a catheter along a vessel comprising: (a) at least one lumen coaxial with at least a portion of a length of the guide wire; and (b) a distal portion positionable within a target site and being pre-shaped to form a coiled structure therein. According to further features in preferred embodiments of the invention described below, the guide wire further comprises at least one opening into the at least one lumen, the at least one opening being along the length of the guide wire.

According to still further features in the described preferred embodiments the coiled structure is sized and shaped for occupying a space or volume within a left ventricle.

According to still further features in the described preferred embodiments the coiled structure contacts walls of the left ventricle without substantially modifying an electrical conductance of the walls.

According to still further features in the described preferred embodiments the at least one opening is in a portion of the guide wire adjacent to the distal portion.

According to still further features in the described preferred embodiments the guide wire further comprises at least one wire disposed within the at least one lumen.

According to still further features in the described preferred embodiments an end portion of the at least one wire can be moved through the at least one opening. According to still further features in the described preferred embodiments the end portion forms a structure when moved out of the at least one opening. According to still further features in the described preferred embodiments the structure is sized and configured for anchoring the guide wire against a tissue structure.

According to still further features in the described preferred embodiments the tissue structure is a heart valve. According to still further features in the described preferred embodiments the heart valve is an aortic valve.

According to still further features in the described preferred embodiments anchoring the guide wire to the aortic valve is effected by juxtaposing the structure against a ventricular side of the aortic valve. According to still further features in the described preferred embodiments the structure is a coil.

According to still further features in the described preferred embodiments the structure is a flower.

According to still further features in the described preferred embodiments the at least one wire includes at least 2 wires and the at least one opening includes at least 2 openings.

According to still further features in the described preferred embodiments a stiffness of the distal portion is lower than the stiffness of the rest of the guide wire.

According to still further features in the described preferred embodiments the at least one wire is capable of conducting an electrical signal to and from a target tissue.

According to still further features in the described preferred embodiments the guide wire further comprises an expandable wire structure attached to the guide wire, the expandable structure being deployable through the at least one lumen.

According to still further features in the described preferred embodiments the expandable structure is deployed via a wire positioned within the at least one lumen.

According to still further features in the described preferred embodiments the expandable structure expands to a structure selected from the group consisting of an umbrella, a mushroom, a tube and a cone.

According to still further features in the described preferred embodiments a length of the guide wire is selected from a range of 100-300 cm.

According to still further features in the described preferred embodiments a length of the distal portion is selected from a range of 50-250 mm. According to still further features in the described preferred embodiments an outer diameter of the guide wire is selected from a range of 0.35-2 mm.

According to still further features in the described preferred embodiments a diameter of the at least one lumen is selected from a range of 0.25-1.9 mm. According to still further features in the described preferred embodiments a diameter of the at least one wire is selected from a range of 0.05-1.5 mm.

According to still further features in the described preferred embodiments the structure is constructed from a radio-opaque material or includes radio-opaque markings.

The present invention successfully addresses the shortcomings of the presently known configurations by providing a guide wire which can be used to locate a tissue structure and stabilize a catheter thereagainst.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. In the drawings:

FIG. 1 illustrates the guide wire of the present invention.

FIGs. 2A-B illustrates the guide wire of the present invention with a deployed spiral-shaped locator-anchor. FIGs. 3A-C illustrate the guide wire of the present invention with an internal flower-shaped locator-anchor in deployed (Figure 3a), closed (Figure 3b) and closed- sheathed (Figure 3 c) positions.

FIG. 4 illustrates the guide wire of the present invention with an external umbrella-shaped locator-anchor. FIGs. 5A-B illustrate the guide wire of the present invention with an external mushroom-shaped locator-anchor in an isometric view (Figure 5 a) and a side view (Figure 5b) showing the movable tube for deploying the mushroom structure.

FIG. 6 illustrates the guide wire of the present invention with an external flower- shaped locator-anchor. FIGs. 7A-8B illustrate another embodiment of the guide wire of the present invention showing the guide wire mounted expandable structure in a non-deployed (Figures 7a-b) and deployed (Figures 8a-b) states. Figures 7b and 8b are magnified views of the areas circled in Figure 7a and 8a (respectively).

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is of a guide wire and method which can be used for positioning and stabilizing catheters at a tissue site. Specifically, the present invention can be used to position and stabilize a catheter used for valvuloplasty or valve replacement thereby substantially enhancing valve replacement accuracy. The principles and operation of the present invention may be better understood with reference to the drawings and accompanying descriptions.

Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details set forth in the following description or exemplified by the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting. Accurately identifying the position of a tissue structure is crucial for successful treatment of disorders associated with such tissue structures. In cases where the target tissue is modified or replaced (e.g. heart valve replacement), stabilization of the target tissue with respect to a surgical device or a delivery catheter is also important. A heart valve is composed of an annulus which supports three thin and pliable leaflets. In the case of an aortic valve, normal aortic valve leaflets spread apart easily and cause no obstruction to outflow of the blood from the heart. In valve replacement therapy, defective leaflet functionality is replaced by a prosthetic valve device which is anchored to annulus tissue and as such, correctly identifying the position of the annulus as well as stabilizing it with respect to a catheter are key to successful treatment.

While reducing the present invention to practice, the present inventors have devised an approach which can be used to identify a target tissue while also enabling stabilization of the target tissue with respect to a catheter delivered to the target tissue. The present approach utilizes a guide wire which is constructed having a co-axial inner lumen capable of carrying a wire, and a distal end portion (away from operator) which is pre-shaped to form a structure capable of occupying a space or volume within a tissue lumen. As is further described hereinunder, in the case of aortic valve repair, the distal portion is constructed for occupying a space or volume within the left ventricle thus stabilizing the guide wire within the left ventricle against pushing forces (on the guide wire). The wire carried within the inner lumen of the guide wire can be pushed out of the inner lumen (e.g. through a side opening) to form a structure which can be juxtaposed against the ventricular side of the valve annulus and/or leaflets thus stabilizing the guide wire against pulling forces while at the same time providing information relating to the position of the valve annulus. Thus, according to one aspect of the present invention there is provided a guide wire capable of guiding a catheter along a vessel (e.g. blood vessel) in a body of a mammal, such as a human.

In as far as its capability to guide an over-the-wire catheter or other medical device within a vessel, the guide wire of the present invention is constructed having a length and outer diameter which enable functionality of a typical guide wire device. In that respect, the present guide wire is preferably constructed having a length and an outer diameter of typical guide wires. The guide wire of the present invention is preferably used as a guide wire for guiding a catheter, such as a valvuloplasty or valve delivery catheter. Positioning of the present guide wire in the vasculature is effected as follows. A 14-35 mil prior art guide wire is threaded through a femoral or axial access sheath through the aorta and the aortic valve and into the left ventricular (LV). A 6-8 French (F) diameter pig nose diagnostic catheter is guided over the guide wire through the valve and into the LV and the guide wire is fully withdrawn. The diagnostic catheter is then used as a conduit for guiding the guide wire of the present invention into the LV; and the catheter is then fully withdrawn.

As is mentioned hereinabove, the present guide wire is designed for facilitating identification of a target tissue and enabling stabilization of a catheter with respect to the target tissue. To enable such functionality, the guide wire of the present invention includes at least one lumen which is co-axial with at least a portion of a length of the guide wire.

The lumen, which preferably spans a length of the guide wire from the proximal end (end manipulated by an operator) to a region near the distal end (end guided through a vessel to a target tissue) includes an opening at or near the proximal end (proximal opening) and at least one opening at a region near the distal end (distal opening). The guide wire further includes at least one inner wire positioned within the lumen. The inner wire serves to deploy or form a two or three dimensional structure around the guide wire. Such a structure serves two functions, a locator function for marking a position within the body, and an anchor function for stabilizing the guide wire against a tissue site within the body.

The guide wire further includes a distal portion which is pre-shaped to form a coiled structure. As is further described hereinbelow, the distal portion is positioned distal to the distal opening described above. The coiled structure serves to stabilize and center the guide wire within a lumen of an organ such as the heart. In addition and as is further described herein, the distal coiled structure can also include radio-opaque markers to enable detection of the location and position of the coiled structure.

The structure and function of the guide wire, lumen and inner wire and the pre- shaped distal portion are further described hereinbelow with reference to the Figures.

Figure 1 illustrates the basic configuration of the guide wire of the present invention which is referred to herein as guide wire 10. Guide wire 10 includes 3 sections, section A, which includes distal portion 12

(which is pre-shaped to form a coil structure), section B, which includes one or more of distal opening 14 and section C, which includes proximal portion 16. Each of sections

A-C is constructed for a specific function and as such each of these sections has a unique property in as far as stiffness, torque ability, flexibility and maneuverability.

Section A is typically flexible and soft. It is designed to gently contact the LV walls without inducing trauma or applying pressure to the walls. The flexibility of section A enables it to easily adopt to the LV shape and size by coiling into a predetermined coiled structure. A preferred stiffness of this section is between 0.5 to 2 grams/mm. Stiffness of the various guide wire sections is expressed herein as bending force over wire deflection. Typical methods of measuring stiffness include measuring the amount of force necessary to deflect a free end of the guide wire fixed to a support a predetermined distance (typically 1 mm). Variations on this basic approach include measuring the amount of deflection of a free middle section of a guide wire trapped between two supports, as well as measuring the amount of deflection resulting from a fixed amount of force on a free section/end of the guide wire.

Section A is constructed from a thin inner metal core surrounded by a flexible spring-like sheath. Use of NITINOL in the metal core enables generation of a predetermined coiled shape. Other materials such as stainless steel may also used. The outer spring-like sheath is typically made of Stainless Steel or NITINOL, cut by laser, and attached to the inner core by means of crimping, gluing and/or welding. The springlike sheath can further by covered by a soft polymeric material (e.g. silicone or ePTFE) to prevent wall tissue erosion and reduce electrical conduction through section A. Other materials and techniques well known to the ordinary skilled artisan may be used to construct Section A.

Section B resides within the aorta side when section A of the guide wire is in the LV. This section guides a catheter carrying, for example, a prosthetic valve through the aortic arc. A catheter carrying a prosthetic valve is relatively bulky and stiff. Hence guiding of a catheter along the guide wire at the aortic arch generates lateral forces which need to be resisted by the guide wire and as such, section B is typically characterized by medium to high stiffness (e.g. 10-40 gm/mm). Longer prosthetic valve fixtures generally required higher stiffness levels for section B of the guide wire. Section B is preferably constructed from a hyper metallic tube, with 35mils external diameter (typically in the range of 20 to 45 mils) and having an internal diameter (of its lumen) in the range of 10 to 30 mils. Additional openings are applied near the distal end of section B as is further described below. These openings can be side or front -facing openings. These openings can be created using machining, laser cutting or the like. The openings are typically ellipse in shape, but can also assume alternative shapes (e.g. round, slit-like etc). The diameter of the openings is designed to enable the expansion of an internal wire structure as is further described below. Typical diameters for an ellipse openings can be in the range of 0.1 to 0.6mm (long axis)and in the range of 0.05 to 0.3 mm (short axis). The tube can be fabricated from stainless steel and/or NITINOL. Alternative materials, shapes and dimensions which can be used to construct section B of the guide wire of the present invention would be well known to the ordinary skilled artisan. Sections A and B can be interconnected via gluing, welding and/or crimping. Section C is preferably constructed from a hyper metallic tube which is contiguous with section B. The distal end of this section resides in the artery leading to the aortic arc, and at its proximal end out the body from the access point (e.g. femoral artery access point). The stiffness of this section will typically be of high (over 40 gm/mm), and in some cases very high (over 50 gm/mm) in order to enable safe and accurate guiding of a catheter from the access point to the target tissue. Since in some cases, the arteries leading to the target tissue can be tortuous and thin, a stiff guide wire section C is needed. Section C would generally be made of similar materials as section B, and would be fabricated using similar methods.

Section B and C are preferably made of the same contiguous tube, with varying stiffness provided by, for example, varying the periodicity of the laser cut thru the tube, and/or by fabricating an internal lumen with varying diameters. Additional control over stiffness, torque ability and flexibility as well as maneuverability can be achieved by varying the characteristics of an inner wire (further described below) which is inserted into the lumen of sections B and C. The length of guide wire 10 ranges from 100 to 300 cm, while its outer diameter

(dl in Figure 1) ranges from 0.35 to 2 mm. Section A (indicated by 14) of guide wire 10 is typically 7.5 to 15 cm in length and has a uniform or varying diameter (conical, tapering towards the tip - distal end). Section B (indicated by 18) is typically 15 to 30 cm in length, while section C (indicated by 16) is typically 75 to 200 cm in length.

As is shown in Figure 1 and mentioned hereinabove, guide wire 10 also includes a lumen 20 which spans a portion of a length of guide wire 10. Lumen 20 has a diameter (d2 in Figure 1) of 0.25-1.9 mm and a length which preferably stretches from a proximal opening 22 to distal opening(s) 14. Proximal opening 22 can be formed at a proximal end 24 of guide wire 10 or at an angle from lumen 20 through a wall 26 of guide wire 10 at proximal portion 16 (not shown in Figure 1). In any case, proximal opening 22 enables an operator to manipulate an inner wire or wires (further described hereinbelow) disposed within lumen 20. Distal opening 14 is provided through wall 26 of guide wire 10 at section B. Distal opening 14 is provided at an angle ranging from 20-160, preferably, 40-120, more preferably 60-100 degrees with respect to lumen 20. Distal opening 14 shown in Figure 1 is angled at 90 degrees with respect to lumen 20.

As is mentioned hereinabove, lumen 20 is designed for carrying an inner wire 28 (not shown in Figure 1). In that respect, distal opening 14 enables an operator to advance inner wire 28 out of lumen 20. As is mentioned hereinabove, inner wire 28 serves to deploy or form a two or three dimensional structure around the guide wire.

Figures 2a-b illustrates guide wire 10 having an inner wire 28 designed for forming structure 30 following advancement out of lumen 20 (not shown) through distal opening 14. Inner wire is generally constructed from a metal alloy or polymer wire having a diameter ranging between 0.05-1.5 mm.

To enable a structure-forming functionality, at least a portion of inner wire 28 is constructed from a shape memory material such as NITINOL or any other pre-formed high elasticity/super elastic material such as stainless steel; the portion forming structure 30 is pre-shaped into a defined structure. When positioned within lumen 20, the structure- forming portion of inner wire 28 maintains a linear configuration due to the trapping forces of lumen 20, however, when the structure-forming portion of inner wire 28 is advanced out of distal opening 14 it generates structure 30. It will be appreciated that since inner wire 28 is formed from an elastic material, it can be pulled back into lumen 20 through distal opening 14 to be re-linearized therein.

Inner wire 28 is formed by coiling an elastic or supper elastic metal wire over a metal-constructed model. The wire is wrapped around the model to create structure 30 and then it is heat treated in a non-oxidizing environment to achieve a stabilized super elastic structure 30.

Structure 30 can be a two dimensional (2D) or a three dimensional (3D) structure having an external diameter (dl in Figure 2) of typically 15 to 28 mm. In the example shown in Figures 2a-b, inner wire 28 is pre-shaped to form an extruded spiral (3D) having a length (L) of typically 15 to 30 mm along the axis of guide wire 10 and a diameter (Dl) of 15-25 mm. Additional structure 30 configurations that can be formed by inner wire 28 include a flat spiral (2D) a ball (3D) or a tube (3D)..

The above configuration of structure 30 is realized using a single inner wire 28 and a single distal opening 14.

Figures 3a-c illustrate a more complex configuration of structure 30 which is constructed from a plurality of elastic wires each deployed through a dedicated distal opening 14.

NITINOL or stainless steel elastic or supper elastic wires are used to construct a preshaped flower-like structure having 4-8 petal-like wire loops. The loop 'petals' can overlap and optionally be interconnected/intertwined. The wires are shaped on a model and heat treated in a non-oxidative environment to form the loops. An additional metal wire is threaded through lumen 20 to create a movable core to which the petal-forming wires will be attached. A plurality of openings 14 (typically 6-16) are laser drilled around the guide wire circumference at section B, about 75-150 mm from the distal tip of the guide wire. Two ends of a single wire are threaded through two openings 14 and the ends are connected to the core wire via welding, gluing crimping or the like. Moving the core wire proximally within lumen 20 pulls the leaf-shaping wires into the hypotube. The wires can be pulled until loops 34 contact the outside surface of the guide wire (in which case, grooves on the surface of the guide wire can be used to make sure that loops 34 are sequestered), or alternatively, wires 28 can be pulled in leaving behind loops and wires which can be covered via an external sheath 40. Sheath 40 can be glued to the hypotube of guide wire 10 distally to openings 14.

The sheathed configuration of structure 30 can be deployed as follows. The core wire is slightly Pulled out to release loops 34 from sheath 40. The core wire is then advanced distally through lumen 20 pushing out inner wires 28 and fully deploying structure 30. To retract the flower configuration of structure 30, the movable core is pulled proximally within lumen 20 thereby pulling inner wires 28 into lumen 20 to a point where loops 34 contact the outer surface of guide wire 10.

Such a configuration of structure 30 is preferably shaped as a flower in order to provide compliance in the radial direction and rigidity in the axial direction. Overlapping of petals minimizes independent movement of each petal and thus ensures that structure 30 functions as a unitary body.

Since structure 30 also functions as an anchor designed for abutting tissue structures (such as a valve annulus) and stabilizing guide wire 10 against such tissue, axial rigidity ensures that such stabilization is not axially compliant. At the same time, radial compliance in structure 30 enables accommodation in a diameter and shape of structure 30 and thus ensures optimal 'fit' between structure 30 and the target tissue. This is especially important in cases where the target tissue is an opening such as a valve annulus which is accessible through a space of varying diameter and geometry (e.g. the ventricle side of the valve). Such radial accommodation is important for both anchoring and locating since both require optimal positioning of structure 30 against the target tissue. In addition to the radial compliance to the annulus, the design of the flower according to a preferred embodiment of the present invention, also designed to have a pitch compliance, so to enable a secured accommodation in cases that the wire is not centered relative to the annulus center.

The flower configuration of structure 30 is preferably 15-25mm in overall diameter and 10-30 mm in length. Each petal covers 6 — 15mm of the overall flower circumference with overlap being 10-40 % of the petal area. Optionally, the petals can be attached, intertwined at the points of overlap of wires 28. Attachment can be facilitated via a sliding ring that encompasses two adjacent wires 28 of different petal. Such a ring can be disposed under sheath 40 when structure 30 is collapsed. Deployment of structure 30 enables rings to translate towards loops 34 and to thereby attach adjacent petal at or near loops 34. In an alternative embodiment, Inner wires 28 of adjacent petals can be crossed or wound around each other to enable attachment of petals.

The above described flower configuration of structure 30 is deployed through radial holes. Assuming that lumen 20 diameter at proximal portion 16 is 1.6mm while at portion 18 its 1.2-1.4 mm, 6 petals each including two ends of inner wire 28 (0.1mm diameter each) can be arranged within lumen 20 and deployed using a single core wire attached thereto.

The above described configurations of structure 30 are termed herein as internal configurations since most or all of the structure is contained within lumen 28 prior to deployment. As is mentioned hereinabove, inner wire 28 can also function in deploying a structure 30 which is positioned externally on guide wire 10.

Figures 4-6 illustrate several embodiments of external structure 30 which is positioned around guide wire 10 in a closed and compressed state (optionally sheathed) and is deployed to an open state via inner wire 28.

Figure 4 illustrates an umbrella configuration of structure 30 in a deployed position. A plurality of elastic/super-elastic wires (NITINOL, stainless steel etc.) are distally connected to a portion 18 of guide wire 10 by means of gluing, welding and/or crimping to create the umbrella ribs 42. Ribs 42 are evenly arranged around portion 18 of guide wire 10. Tips 44 of ribs 42 are interconnected via a wire ring 46, while each rib 42 is also connected to a central runner 48. In the collapsed state (not shown), ribs of structure 30 are trapped under an external sheath 50. Using a first inner wire 28 (not shown) to pull sheath 50 proximally will release ribs 42 and deploy structure 30 which will assume an umbrella shape. Structure 30 is collapsed by pulling runner 48 in proximal direction using a second inner wire 28 (not shown) causing ribs 42 to fold concentrically against guide wire. Collapsed structure 30 can then be sheathed via sheath 50 which can be pushed distally via first inner wire 28.

Figures 5a-b illustrate a mushroom-shaped structure 30 in a deployed position. Elastic or supper elastic wires are used to weave a tube-like initial shape. The woven wire tube is then reshaped by means of thermal treatment to create the predefined mushroom shape which can be stretched back to the tube shape. A distal end 31 of the mushroom-shaped structure 30 is attached to a core wire 33, while a proximal end 35 of structure 30 is attached to a tube 37. Tube 37 and core wire 33 can extend proximally and out of the body. A relative movement of tube wire 35 and tube 37 will cause structure 30 to expand (if tube is pushed while core is stationary) or stretch and become "tube"-like when tube 37 is pulled with reference to stationery core wire 35. Alternatively, an inner wire 28 is connected to tube 37 and used to pull/push tube 37. In any case, pulling of tube 37 proximally stretches out structure 30 in a proximal direction. As a result structure 30 forms a tube covering guide wire 10 (not shown). Pushing tube 37 distally expands structure 30 to the shape shown in Figures 5a-b.

Figure 6 illustrates a flower-shaped structure 30 which is carried around guide wire 10. In this case, the flower is constructed and deployed in a manner similar to that of the umbrella-shaped structure 30 of Figure 4.

As is mentioned hereinabove, structure 30 also functions as a locator. In that respect, structure 30 is fabricated from a radio-opaque material or includes radio-opaque markings. Portions 12 and 18 of guide wire 10 can also include radio-opaque markers disposed along their length. The latter configuration is advantageous in that use of a specific pattern of radio-opaque markers on structure 30 can assist in determining not only the general location of structure 30 but also its angle with respect to the target tissue and its degree of radial deformation. Such a pattern can be created by, placing a single radio-opaque dot on each of the loops forming the end of the petals of the flower-shaped structure 30 of Figures 3a-b.

Since structure 30 is constructed from metal wires, it can be used to deliver electrical signal to tissue and/or receive electrical signals therefrom.

For example, when structure 30 is deployed within the LV, it can be used to deliver electrical signals to the walls of the LV for the purpose of pacing. Additional or alternative sensing of electrical signals from the walls of the LV can provide clinical information as to the functioning of the heart during a procedure and indicate to a physician whether there is need to pace the heart during the procedure. For example, in percutaneous valve replacement, structure 30 can be used to pace the heart during the critical phases of prosthetic valve placement. To provide optimal functionality, structure 30 preferably includes several key characteristics and features:

(i) elasticity in the axial (along the length of guide wire 10) and radial directions as well as pitch;

(ii) reduced deformation in the axial direction and increased deformation in the radial direction;

(iii) adaptive abutment of tissue structures (such as a valve annulus), i.e. it can accommodate a range of annulus sizes in the case of heart valves. (iv) wire or wires 28 are radio-opaque or include radio-opaque markings; and

(v) wire or wires 28 are electro-conductive or include conductive coatings;

In order to further facilitate use of guide wire 10 as a tissue locking device in PVR procedures, portion 18 of guide wire 10 proximal to openings 14 can include a locking mechanism that can engage a distal portion of a valve delivery catheter. Such a locking mechanism, which can include a friction element, a magnetic element or a toothed element can be used to further stabilize the catheter on guide wire 10 and thereby further reduce movement thereof during deployment and positioning of the prosthetic valve.

Actuation of structure 30 of guide wire 10 is effected using a handle connected to a proximal end 24 of guide wire 10 (which resides out of the body when guide wire 10 is in position). The handle is connected to walls 26 of guide wire 10 (forming the outer hyper tube) as well as inner wire 28 or tube 50 in the case of the embodiment described with respect to Figures 5a-b. Actuation of the handle enables relative movement between the outer hyper tube of guide wire 10 and inner wire 28 (or tube 37). Several handle features are envisaged:

(i) Lock external hyper tube to internal wire 28 to maneuver guide wire 10 in and out and accurately located structure 30 following deployment. (ii) Push internal wire 28 relative to hyper tube or hyper tube relative to internal wire 28 to deploy structure 30. Such movement can be effected by a single actuation force (to a mechanical stop) for full deployment or in a stepwise fashion (partial deployment in each step); the latter will enable better control over guide wire 10 location as structure 30 is deployed. The handle will lock internal wire to hyper tube following each deployment actuation step.

(iii) Pull internal wire 28 relative to hyper tube or vise versa to collapse structure 30. As in (ii), collapse can be effected via a single actuation step or via multiple steps (partial collapse in each step). The handle will lock internal wire to hyper tube following each deployment step. (iv) A "quick" engage and release mechanism for engagement/disengagement of the handle to proximal end 24 of guide wire 10. Guide wire 10 can be used in medical procedures which require tissue marking/locating and tissue anchoring. Examples include valvuloplasty, percutaneous valve repair or replacement, stent positioning, as well as procedure conducted through other vessels or conduits in the body (e.g. urological procedures). In general, guide wire 10 is utilized in a manner similar to prior art guide wires.

For illustrative purposes, the guide wire described in the procedure is that illustrated in Figures 3a-c. Briefly, in a PVR procedure the physician first guides a standard guide wire, through an access site (typically in a femoral artery) to the aortic arc and into the aortic valve. This first guide wire is used to get access into the LV through a stenoic aortic valve. Once a path is established by the first guide wire, a 6F diagnostic catheter is threaded onto the first guide wire and the catheter tip is pushed into the LV. The physician than removes the first guide wire, and uses the catheter to position guide wire 10 of the present invention with distal portion 12 in the LV. Since the catheter is already positioned in the LV, it is relatively simple for the physician to access the LV with guide wire 10. Once guide wire 10 is in the LV, it is pushed out of the catheter until distal portion 12 assumes its pre determined coiled shape filling the LV volume. At this point, the physician retracts the diagnostic catheter, leaving guide wire 10 in place. The physician then deploys structure 30 by gently pulling inner wire 28 to release the petals of the flower and then pushing inner wire 28 until structure 30 is fully expanded in the LV. The entire procedure is monitored by a C-arm system which images radio opaque markers on structure 30. After expanding structure 30, the physician pulls back guide wire 10, until the petals of structure 30 lean about the aortic valve from the LV side.

The physician can now adjust the projection plane of the C-arm to be perpendicular to the annulus. When correctly aligned, the markers on structure 30 are arranged in a single plane in perpendicular imaging. A valvuloplasty balloon is then threaded over guide wire 10, and guided to the LV. Markers on both the valvuloplasty balloon catheter as well as on guide wire 10 and structure 30 ensure accurate positioning of the balloon at the stenoic valve. The balloon is inflated to deploy the valve and then deflated and retracted. A second catheter carrying a prosthetic valve is then guided over guide wire 10 until radio opaque markers on the prosthetic valve correctly correspond to markers on guide wire 10 and structure 30. Optionally, the delivery catheter carrying the prosthetic valve is advanced until stopped at the base of structure 30, which ensures correct positioning and stabilization of the catheter and accurate deployment of the attached prosthetic valve. The catheter can further be locked to guide wire 10 by means of a locking mechanism to provide additional stabilization. The locking mechanism can be contained in guide wire 10, or alternatively implemented by a special fixture on the valvuloplasty and/or PVR catheter. Such a fixture can be locked to a mating fixture provided on guide wire 10. The physician then expands the prosthetic valve in position and removes the delivery catheter out the body. Structure 30 is than folded back, by pulling on the core wire connected to inner wires 28 forming structure 30. Guide wire 10 can then be pulled out of the body or pulled into a catheter and pulled out of the body. Figures 7a-8b represent another configuration of the guide wire of the present invention which is referred to herein as guide wire 100.

Guide wire 100 includes an inner member 102 which has an outer diameter (OD) of 0.4-0.7 mm. Guide wire 100 also include a hypotube 104 (OD of 0.8-0.9 mm) which is fitted over inner member 102. Hypotube has two non-contiguous sections, a distal hypotube 105 which is attached to inner member 102 and a proximal hypotube 107 which can slide over inner member 102. An expandable wire structure 106 (similar in function to structure 30 described above) which can be manufactured by laser cutting a tube or by shaping and welding a wire etc. is attached to proximal hypotube 107 via a mounting ring 108 having an OD of 1-2 mm. (The base of each strut 110 forming expandable wire structure 106 is attached to a proximal hypotube 107 via a mounting ring 108 using crimping, gluing or welding approaches.)

Guide wire 100 further includes a retaining ring 112 which is attached via welding, gluing etc. to distal hypotube 105. Retaining ring 112 includes spokes which limit struts 110 from moving out of retaining ring 112 in a proximal direction. Retaining ring 112 maintains expandable wire structure 106 compressed against hypotube 104.

The overall OD of guide wire 100 is 2-3 mm enabling threading of this guide wire through a 7-8 F catheter.

When proximal hypotube 107 is advanced distally over inner member 102, struts 110 of expandable wire structure 106 move out of retaining ring 112 and expand radially (Figures 8a-b). To facilitate movement of struts 110 out of retaining ring 112, the region of guide wire 100 lying between mounting ring 108 and retaining ring 112 (as shown in Figure 7a) does not include hypotube 104. This enables mounting ring 108 to move towards retaining ring 112 until mounting ring 108 contacts retaining ring 112 (Figure

8a). It will be appreciated that although struts 1 10 are shown exposed in Figure 7a, a covered configuration utilizing a sheath to cover struts 110 can also be realized in which case, the sheath can slide into proximal hypotube 107 or accordion during actuation. Struts 110 are preferably fabricated from a shape memory alloy such as Nitinol which is preshaped to form a flower-like structure when released from retaining ring 112. The flower-like shape formed from struts 110 of expandable wire structure 106 has a diameter of 18-28 mm and can maintain a pulling force of 0.1-1 kg when juxtaposed against tissue. Guide wire 100 can be used to locate a catheter at a tissue site (e.g. an aortic valve) as follows. A 7-9 F catheter is used to position guide wire 100 with distal portion 114 in the left ventricle (preferably coiled therein). To facilitate coiling and prevent damage to the interior wall of the ventricle, distal portion 114 of guide wire 100 is preferably fabricated from a shape memory alloy core (inner member 102 - Nitinol) which is wrapped with a soft elastic cover (hypotube 104 - Silicone). The catheter is retracted and expandable wire structure 106 is deployed by holding inner member 102 and pushing hypotube 104 distally. Once expandable structure 106 is fully expanded (partial expansion is also possible), guide wire 100 is moved in order to position expandable wire structure 106 against the valve annulus (e.g. pulled to position it against the ventricular side of the valve). A catheter delivering a prosthetic valve or balloon is then advanced over guide wire 100 and the catheter tip is positioned against mounting ring 108 (and optionally locked thereto using a locking interface, e.g. a magnet). The catheter is then used to perform a procedure (e.g. prosthetic valve deployment or valvuloplasty), following which the catheter is pulled back and removed from the body. Guide wire 100 is then pushed distally to free expandable wire structure 106 from the valve annulus. Inner member 102 is then held in position and hypotube 104 is pulled proximally to move retaining ring 108 over struts 110 in order to compress struts against hypotube 104. The 7-9 F catheter is then reintroduced over guide wire 100 and once guide wire 100 is fully contained, the catheter and guide wire 100 are removed from the body. It is expected that during the life of this patent many relevant catheters will be developed and the scope of the term catheter is intended to include all such new technologies a priori.

As used herein the term "about" refers to + 10 %.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.

Claims

WHAT IS CLAIMED IS:

1. A guide wire being capable of guiding a catheter along a vessel comprising:

(a) at least one lumen co-axial with at least a portion of a length of the guide wire; and

(b) a distal portion positionable within a target site and being pre-shaped to form a coil therein.

2. The guide wire of claim 1, further comprising at least one opening into said at least one lumen, said at least one opening being along said length of the guide wire.

3. The guide wire of claim 1, wherein said coil is sized and shaped for occupying a space or volume within a left ventricle.

4. The guide wire of claim 3, wherein said coil contacts walls of said left ventricle without substantially modifying an electrical conductance of said walls.

5. The guide wire of claim 2, wherein said at least one opening is in a portion of the guide wire adjacent to said distal portion.

6. The guide wire of claim 5, further comprising at least one wire disposed within said at least one lumen.

7. The guide wire of claim 6, wherein an end portion of said at least one wire can be moved through said at least one opening.

8. The guide wire of claim 7, wherein said end portion forms a structure when moved out of said at least one opening.

9. The guide wire of claim 8, wherein said structure is sized and configured for anchoring the guide wire against a tissue structure.

10. The guide wire of claim 9, wherein said tissue structure is a heart valve.

1 1. The guide wire of claim 10, wherein said heart valve is an aortic valve.

12. The guide wire of claim 11, wherein anchoring the guide wire to said aortic valve is effected by juxtaposing said structure against a ventricular side of said aortic valve.

13. The guide wire of claim 8, wherein said structure is a coiled structure.

14. The guide wire of claim 8, wherein said structure is a flower.

15. The guide wire of claim 6, wherein said at least one wire includes at least 2 wires and said at least one opening includes at least 2 openings.

16. The guide wire of claim 1, wherein a stiffness of said distal portion is lower than said stiffness of the rest of the guide wire.

17. The guide wire of claim 6, wherein said at least one wire is capable of conducting an electrical signal to and from a target tissue.

18. The guide wire of claim 1, further comprising an expandable wire structure attached to the guide wire, said expandable structure being deployable through said at least one lumen.

19. The guide wire of claim 18, wherein said expandable structure is deployed via a wire positioned within said at least one lumen.

20. The guide wire of claim 18, wherein said expandable structure expands to a structure selected from the group consisting of an umbrella, a mushroom and a tube.

21. The guide wire of claim 1, wherein a length of the guide wire is selected from a range of 100-300 cm.

22. The guide wire of claim 1, wherein a length of said distal portion is selected from a range of 50-250 mm.

23. The guide wire of claim 1, wherein an outer diameter of the guide wire is selected from a range of 0.35-2 mm.

24. The guide wire of claim 1, wherein a diameter of said at least one lumen is selected from a range of 0.25-1.9 mm.

25. The guide wire of claim 6, wherein a diameter of said at least one wire is selected from a range of 0.05-1.5 mm.

26. The guide wire of claim 8, wherein said structure is constructed from a radio-opaque material or includes radio-opaque markings.

27. A guide wire being capable of guiding a catheter along a vessel comprising:

(a) a distal portion positionable within a target site and being pre-shaped to form a coiled structure therein; and

(b) an expandable wire structure attached to the guide wire and being sized and configured for anchoring the guide wire against a tissue structure when in an expanded state.

28. The guide wire of claim 27, wherein said expandable wire structure forms a flower-like shape when in said expanded state.

29. A method of guiding a catheter to a specific tissue site comprising:

(a) guiding a guide wire having a deployable wire structure thereupon to the tissue site;

(b) deploying said deployable wire structure in a vicinity of the tissue site;

(c) positioning said deployable structure against a tissue of the tissue site by pulling or pushing the guide wire; and

(d) guiding the catheter over the guide wire to the tissue site using said deployable structure as a reference.