DEFORMATION OF THE DISTAL PORTION OF A GUIDEWIRE

Technical Field

The invention concerns a guidewire for vascular navigation procedures, and in particular a guidewire having a distal portion that may be manually deformed in to a selected bent shape when ex-vivo, and reversibly redressed to a straight shape state when engaged in vivo.

Background Art

Guidewires are often used in medical procedures. Since guide wires must be advanced within the patient's tortuous anatomy, the guidewire must bear enhanced steerability and be capable to display high torque characteristics.

To assist the steering and progress of a guidewire within an anatomy, a guidewire is usually inserted into a patient's body with a distal portion having a curved shape known in the art as a j-shape configuration. Nowadays some manufacturers supply guidewires with a distal portion having a given j-shape, which is preformed in factory. Other manufacturers deliver guidewires having a straight distal portion, which is deformed into a j-shape by the practitioner prior to insertion in vivo, but once deformed, the distal portion cannot be redressed to the straight shape when in vivo. In vascular procedures, the distal end of a guidewire may need to be formed into many different shapes according to the reference diameter and the nature of the vasculature to be treated. Furthermore, the practitioner may need to redress the guidewire into a straight shape while navigation in vivo.

The background art refers to guidewires that are supplied preformed into a predetermined j-shape and may be redressed to the straight shape in vivo, such as for example U.S. Patent Application No. 20020082523 by Kinsella et al., and U.S.

Patent No. 6,599,254 by Winters. However, the preformed predetermined j-shape is not necessarily the bent shape a practitioner may desire to introduce in vivo.

It would therefore be desirable to provide a practitioner with the ability to select an operational bent shape dedicated to the vasculature of the body to be treated, and not be limited to a given preformed j-shape that cannot be redressed once in vivo.

Disclosure of Invention

Presently, a practitioner desiring to navigate the vasculature of a body may chose a tool, such as a catheter or a guidewire, having a given-form distal portion for introduction in vivo. Such a tool is presented with either a distal portion having a straight shape, or with a factory-set distal portion shape, such as a j-shape, that . may be deflected in vivo to the straight shaped state by help of a control handle disposed ex vivo. Therefore, the presently available distal tool shapes are not

adapted to the desires and needs of the practitioner and do not accommodate the requirements regarding vascular navigation related to a specific body. The problem is thus that the navigation tool is not tailored to match the vascular navigation needs for an intervention in vivo on a specific body. The solution is presented by a method and an apparatus allowing the practitioner to manually deform and bend the distal end of the tool or guidewire when ex vivo into any selected predetermined desired bent operational shape for use in vivo. The selected bent operational shape is retained as the operational distal end shape of the guidewire, allowing the practitioner to navigate and use the guidewire in vivo, and allowing the practitioner to operate a proximal control handle to reversibly redress the selected distal bent operational shape into a straight shape.

The practitioner is thus able to deform and deflect the distal end of the guidewire to any desired or required shape when ex vivo, and to repetitively and reversibly redress and straighten the predetermined shape when in vivo.

There is a need for a guidewire having a distal portion configured into a factory-set initial shape, either straight or curved, that enables the practitioner to manipulate the distal portion of the guidewire into a selected operational shape required for a specific vascular procedure. Since thisMistal end shape varies from one body to another, or from one procedure to another, the practitioner needs to be able to shape the distal portion into a selected geometrical operational shape in situ, according to the requirements of the body on which the intervention takes place.

Furthermore, there is also a need to facilitate vascular navigation, whereby, when in vivo, the practitioner is allowed to abandon the manually set and selected bent operational distal end shape, and to reversibly erect the distal portion into a straight shape, by use of the control handle disposed ex vivo. The practitioner is thereby provided with the ability to manually set the distal portion into a selected bent shape while ex vivo, to introduce and navigate the distal portion into the vasculature of a specific body, and while in vivo, to redress the distal portion into a straight shape, still allowing him to return to the selected bent shape when necessary, by operation of the control handle disposed ex vivo, and this in repetitive sequential and successive steps.

In other words, the practitioner must be permitted to both set and select the distal end into a selected bent operational shape necessary to match the requirements imposed by the vasculature of the body upon which the procedure is exercised, and to also reversibly redress the distal end D to a straight shape.

Brief Description of Drawings

In order to understand the invention and to see how it may be carried out in practice, a preferred embodiment will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: Fig. 1 depicts the distal portion of one embodiment of a guidewire,

Fig. 2 shows the distal portion of the guidewire of Fig. 1 after being deformed into a selected operational bent shape, and

Fig. 3 illustrates the distal portion of the guidewire of Fig. 1 after being redressed into the compressed straight shape. Modes for Carrying out the Invention

Fig. 1 is a schematic representation of the unstressed distal portion IOOD of a catheter or guidewire 100 in original supply shape, for example in straight extended elongated shape. The guidewire 100 has a proximal portion IOOP and a proximal control handle H, or other proximal control device(s) H, not shown in the Figs, for the sake of simplicity since well known to the art. Likewise, the practitioner P and the treated body B are not shown in the Figs., again for the sake of simplicity.

Regarding the structure of the guidewire 100, reference is made to previous applications by the same applicant, namely International Application No. WO/2005/120628, and International Application No. PCT/IL2007/001 141, which are both included herewith in whole by reference.

Fig. 1 depicts the configuration of the distal portion IOOD of the guidewire 100. Structurally, the guidewire 100 includes a controlled flexible core wire 11 passing through and being supported by a flexible tubular member 13, which has a distal member termination 13D. The flexible tubular member 13 permits relative motion therein of the flexible core wire 11 in translation and in rotation. Similarly, the core wire 11 ends distally in a core wire tip 15, and both the core wire 11 and the flexible tubular member 13 are proximally coupled to the control handle H, even though this is not shown in the Figs. In the Figs. 1 to 3, a flexible wound coil 17 has a proximal extremity 17P that may be fixedly coupled to the distal member termination 13D of the flexible tubular member 13, by any means known in the art. Such means include for example, gluing, welding, brazing, mutual tight mechanical force fit, or any other conventional means. The flexible wound coil 17 also has a distal wound coil extremity 17D facing the guidewire tip 15. The flexible wound coil 17 thus has an interior diameter wherethrough the distal portion of the flexible core wire 11 may freely move respectively thereto in relative translation and rotation. However, the interior diameter at the wound coil extremity 17D of the wound coil 17, even

though larger than the diameter of the core wire 11, is smaller than, and prevents the passage therethrough of the external diameter of the guidewire tip 15.

The control handle H is appropriately coupled in engagement with the proximal portions of the flexible core wire 11 and of the tubular member 13, whereby the practitioner P may command and operate relative translation and rotation between the core wire 11 and the tubular member 13. The control-handle

H may lock only the core wire 11, or only the tubular member 13, or lock both.

For proceeding with the operation, the practitioner P receives the distal portion IOOD of the guidewire 100 in an original supply shape I, for example the shape shown in Fig. 1. Such an initial original shape I, may be supplied with the distal guidewire end IOOD being disposed either in straight extended elongated shape, or in an a priori curved shape, thus in any predetermined curved shape, wherein the core wire 11 is disposed in stressed plastic deformation. Such a curved shape may for example the shape depicted in Fig. 2, which may also be the shape the practitioner P may select for use.

Should the original supply shape I be a preformed curved shape but not bent as desired by the practitioner P, then that preformed curved shape may be deformed by the practitioner into any desired selected bent state II, as described hereinabove with respect to a straight extended elongated shape. The practitioner P may then seize and manually operate a plastic deformation on the distal portion IOOD, and thus on the core wire 11, to achieve a selected bent operational shape. The manual application of stresses may induce the core wire 1 1 to plastically deform, for example into the shape II as shown in Fig 2. This means that the core wire 11, but not the wound coil 17, may become plastically deformed into a selected bent operational shape II.

Fig. 1 is a schematic representation of the distal portion IOOD of a catheter or guidewire 100 in initial original supply shape I, shown for example as a straight extended elongated shape.

Fig. 2 shows the distal portion IOOD of the guidewire 100 after being deformed into a selected operational bent shape II, thus after the core wire 11 has incurred the plastic bending deflection stresses imparted manually by the practitioner P, to achieve a desired shape II ready for insertion in vivo. It is noted that the wound coil 17 may have undergone a deflection larger than the deflection suffered by the core wire 11. Such a deflection of the wound coil 17 may possibly require a relative translation of the tubular member 13 over the core wire 11 , which may demand an appropriate setting or operation of the control handle H to permit that kind of relative motion.

After being introduced in vivo, the guidewire 100 may be navigated into the vasculature of the treated body B and the procedure may be operated, with the

distal portion IOOD remaining in the selected operational bent shape II for as long as desired by the practitioner P.

However, when the practitioner P so decides, the distal portion IOOD may be reversibly redressed into a compressed straight shape coextensive with the tubular member 13. Thereafter, the practitioner P may return to the selected bent operational shape II and subsequently repeat the redressing operation to the compressed straight shape in sequence as often as desired.

Fig 3 illustrates the configuration of the distal portion IOOD after being redressed from the selected bent operational shape shown in Fig. 1, into the compressed straight shape III.

Straightening of the distal portion IOOD into the compressed straight shape III may be achieved by manipulation of the control handle H to apply tension stresses to the core wire 11 and compression stresses to the wound coil 17, relative to the tubular member 13. The wound coil 17 may now become solidly seated in straight tightly compressed, or coil-on-coil straight compressed-coil state III configuration, and in compression between the guidewire tip 15 and the distal portion 13D of the tubular member 13.

The applied elongation and compression stresses, opposed to the relaxed and unstressed condition present with the initial original supply shape I shown in Fig. 1, are necessary to redress the distal portion IOOD into the tightly compressed-coil straight shape III depicted in Fig. 3.

To redress the distal portion IOOD to the compressed-coil straight shape III, the control handle H may be operated to pull the core wire 11 proximally relative to the tubular member 13. The pull induces tension stresses on the core wire 11, and redresses the wound coil 17 by exerting compression forces between the guidewire tip 15 and the distal extremity 13D of the tubular member 13. The control handle H may thus be operated, for example, to allow proximal retraction of the core wire 11 relative to the tubular member 13, which may be locked in stationary position. Thereby, the wound coil 17 becomes fully seated straight and compressed in a closed coil-to-coil shape III, as shown in Fig. 3.

When the tension stresses pulling the core wire 11 proximally are released, the distal portion 10OD may regain the selected bent operational state. This occurs since the core wire 11 still remains in plastic deformation.

In turn, redress of the distal portion IOOD to the compressed shape III, and reversible release to the selected bent operational shape II may be repeated in sequence as often as desired.

Deformation is a change in shape resuting from the application of external forces on a body. To deform the distal guidewire end IOOD, the practitioner P applies forces and bending moments intended to drive the material from which the

core wire 11 is made, past the elastic stress range and into the plastic range. Preferably, control is exerted on the deformation that may be imparted to the guidewire 100 and to the core wire 11.

The deformation of the core wire 11 may be governed by a number of parameters, such as for example the type of the selected material, and the thickness of the core wire 11.

Practically, a material for the core wire 11 may possibly be selected as Nitinol having well known characteristics, but alloys of Nitinol, and alloys of other metals may also provide properties advantageous for the control of the deformation of the core wire 11. Nitinol, for example, may withstand deformations ranging from 10% to 12%, while Stainless Steel may support deformations of up to 0.5%. Proper selection of material and alloying may thus provide control of the deformation of the core wire 11.

An additional option intended to lower the deformation percentage of the core wire 11 may be to replace a Nitinol core wire with a wire having a platinum core coated with Nitinol. Such a platinum core will also enhance the radiopacity of the . core wire 11 since platinum is known for its high visibility under fluoroscopy. In ^; general, the deformability of the core wire 11 may be altered by alloying, thus by the addition of other metals, such as copper for example. Since the relative deformation of the core wire 11 is in direct relation with the thickness thereof, and in inverse relation with the radius of bent, the thickness of the material chosen to implement the core wire 11 is also instrumental for the, control of the deformation.

The use of the guidewire system and of the method for operating an intrusive procedure is thus straightforward to a practitioner in view of the description detailed hereinabove. The practitioner makes use of the guidewire 100, having a . distal guidewire end IOOD for use in vivo, and a proximal guidewire end disposed ex vivo to which a control handle (H) is coupled. To facilitate use, the guidewire 100 has a flexible core wire 11 with a distal core wire tip 15, and a flexible tubular member 13 with a distal member termination 13D for supporting and allowing relative motion of the flexible core wire therein. Furthermore, the flexible wound coil 17 has a proximal wound coil extremity 17P and a distal wound coil extremity 17D intermediate the distal member termination and the guidewire tip. Moreover, the proximal wound coil extremity is fixedly coupled to the distal member termination.

When still ex vivo, the distal guidewire end is received as is by the practitioner, thus in the original supply shape I. However, the practitioner may deform the distal guidewire end by manual plastic deformation into a selected bent shape II, as desired.

Then, the practitioner introduces the guidewire 100 in vivo and proceeds along the following steps: a. the procedure is operated with the distal guidewire end being disposed in the selected bent state, b. the control handle to which the flexible core wire and the flexible tubular member are proximally coupled, is used to tightly compress the wound coil into a straight compressed-coil state and redress the distal guidewire end into a compressed straight shape (III), c. the procedure being operated with the wound coil being disposed in the compressed straight shape, and d. the distal guidewire end being returned to the selected bent shape by use of the control handle.

If so desired, the practitioner may choose to operate by sequential repetition of all the steps a to d, or by repetition of the steps a to c, or else, by repetition of the steps a, b, and d.

For ease of use, the distal guidewire end may be deformed and redressed in situ. Accordingly, the core wire is configured to be manually deformable by plastic deformation into a selected shape, which then becomes the selected bent shape that the practitioner may wish to use. When used in vivo, the wound coil is configured to allow reversible deformation and remain within elastic stress limits when tightly compressed into the compressed straight shape.

Sometimes, the original supply shape of the wound coil is a predetermined curved shape, which the practitioner may accept as being the selected bent shape, and if so, he may then proceed to operate by sequential repetition of the steps a to d, or by repetition of the steps a to c, or else, by repetition of the steps a, b, and d.

Industrial Applicability

The embodiments described hereinabove are suited in general for manufacture by producers of medical apparatus, and more specifically, by vendors of instruments configured for invasive procedures.

It will be appreciated by persons skilled in the art, that the present invention is not limited to what has been particularly shown and described hereinabove. For example, more than one coil 17 may be used if desired, and the wire of coil may be multi-stranded. Rather, the scope of the present invention is defined by the appended claims and includes both combinations and subcombinations of the various features described hereinabove as well as variations and modifications thereof which would occur to persons skilled in the art upon reading the foregoing description.