Abstract:
A guidewire converter for use in intravascular procedures along with a guidewire. The guidewire converter includes an elongate tubular structure defining a lumen having an inner diameter and a first outer diameter. The inner diameter of the lumen is sized to receive the guidewire for intravascular procedures. The guidewire converter includes a locking mechanism coupled to the elongate tubular structure that has a second outer diameter that is less than or substantially equal to the first outer diameter. Operation of the locking mechanism releasably secures the elongate tubular structure to the guidewire.

Description:
FIELD OF THE INVENTION 
     The invention generally relates to guidewires that are used to guide medical instruments through the human vascular system. More particularly, the invention relates to the exchange of different guidewires having different qualities. 
     BACKGROUND OF THE INVENTION 
     Guidewires are commonly used in many medical procedures to assist a physician in gaining access to blood vessels within the body to insert instruments. For example, medical procedures involving accessing blood vessels in and around the heart often include making an incision in the femoral artery in the area of the groin or upper thigh, and inserting a medical guidewire into the femoral artery. A physician then manipulates the guidewire while observing it under fluoroscopy or by other imaging techniques to guide the guidewire to a desired location, for example, within the blood vessels in and around the heart. 
     Guidewires are available in a variety of sizes and configurations. For example, guidewires sizes include but are not limited to diameters of 0.014 inches and 0.035 inches. Guidewires are also available with a variety of tips in a variety of shapes and stiffnesses to accommodate the needs of physicians and to facilitate their manipulation of the guidewires through blood vessels. 
     Stylets and catheters are also used to access blood vessels in the human body to facilitate the introduction of intravascular leads, stents and other intravascular devices into the veins or arteries of the body. Although both stylets and guidewires are often thought of as simply very small wires, the purpose and operation of guidewires is significantly different as compared to stylets. 
     Intravascular procedures typically involve an initial step of introducing and routing a guidewire through a patient&#39;s vascular system to provide a rail or track along which additional intravascular devices may be introduced. Once a guidewire is in place, an introducer sheath catheter is routed over at least a portion of the guidewire to provide a larger opening into the vein or artery and sometimes to protect the inside walls of the vessels along the route of the guidewire. With the introducer in place, the guidewire may be removed or may remain in place as additional intravascular devices, such as intravascular leads, stents and catheters are introduced into the patient&#39;s vascular system. 
     To better accomplish the purpose of a guidewire providing a track along the patient&#39;s vascular system for other intravascular devices, it is desirable that the guidewire be extremely flexible and preferably have the ability to vary the flexibility of the distal tip and/or deflect the distal tip so as to aid in routing the guidewire through the patient&#39;s vascular system. 
     In contrast to the guidewire that serves as a track over which other intravascular devices are routed, a stylet is used within an internal lumen of an intravascular device both to push that device through the vascular system and to steer the device as it is being pushed. Although some intravascular devices are designed to steer themselves using internal core wires, almost all leads and some catheters have an inner channel or lumen into which a stylet may be inserted. 
     In addition to pushing the intravascular device through the vascular system by engaging the distal end of the device, the stylet also serves to deflect the distal end of the intravascular device so as to steer the distal end through the vascular system. Unlike the lead, catheter or guidewire, which is highly flexible and floppy, the stylet must be stiffer and more rigid so as to enable the stylet to push the lead or catheter through the patient&#39;s vascular system. 
     Conventionally, stylets having different bends on the distal end are used at different points of advancing the lead or catheter to a desired location. For straight segments of a vessel a straight stylet is used, whereas a stylet with a curved distal tip is used to navigate the lead or catheter through a curved portion of a vessel. 
     It is often necessary to change guidewire size during medical procedures. Currently, changing guidewire size involves withdrawing a guidewire that is currently located in the blood vessel and inserting a different size guidewire into the blood vessel and guiding it to the position previously occupied by the original guidewire. This can be a time consuming procedure, which lengthens the time necessary to a complete a medical vascular procedure and may increase discomfort and risk for the patient. In general, it is desirable to complete invasive medical procedures such as medical vascular procedures as quickly and efficient as possible to minimize stress on the patient. 
     Thus, there is room for improvement in the guidewire arts to improve efficiency and minimize time required to complete vascular medical procedures. 
     SUMMARY OF THE INVENTION 
     The present invention solves many of the above-referenced problems. A convertible guidewire of the present invention generally includes a guidewire and a guidewire converter. 
     The guidewire may be generally conventional and has a diameter smaller than the guidewire converter. The guidewire generally also has a length greater than that of a guidewire converter. For example, the guidewire may have an outside diameter of 0.014 inches while the guidewire converter has an outside diameter 0.035 inches. The guidewire converter covers a substantial portion of the length of the guidewire. For example, the guidewire converter may have a length of between about eighty and about one hundred forty five centimeters. Guidewires generally have a length of eighty to three hundred centimeters. These lengths should not be considered limiting. 
     Generally, in an example embodiment, the guidewire converter includes a distal sleeve portion and a locking portion. The distal sleeve portion may include a more rigid proximal portion and a less rigid portion that is distal to the more rigid distal portion. To ease the transition from the guidewire to the guidewire converter, the guidewire converter generally may include a tapered distal end. The tapered distal end may include a radiopaque marker band to facilitate visibility of the end of the guidewire converter to x-rays and fluoroscopy. 
     In an example embodiment, the lumen of the guidewire converter may be lined with a liner that covers the interior of the lumen. The liner may be formed of, for example, PTFE/polyimide or another polymer material. The more rigid portion of the guidewire converter may be formed from a polymer material, for example, nylon 12. 
     The less rigid portion of the guidewire converter may be formed from, for example Pebax having a Shore hardness of 55d, or another suitable biocompatible polymer. 
     In one embodiment, the distal sleeve portion of the guidewire converter may be externally coated with a hydrophilic coating. 
     Generally, the locking portion of the guidewire converter is constructed so as to have a maximum outer diameter that is no greater than the outer diameter of the distal sleeve portion  16 . In an example embodiment, if the distal sleeve portion has an outside diameter of 0.035 inches, then the locking portion should have a maximum outside diameter of 0.035 inches or less as well. These particular dimensions should not be considered to be limiting. 
     An example locking portion includes a locking sleeve and a collet. The locking sleeve is slidably movable over the collet and includes a tapered tube having a cylindrical portion and a tapered portion. The locking sleeve is slidably engageable to the collet so that when the fingers of the collet are within the cylindrical portion they are released from a guidewire that is inside the guidewire converter and so that when the locking sleeve is advanced so that the fingers of the collet are within the tapered portion they are frictionally squeeze down to engage a guidewire within the guidewire converter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view of a guidewire converter in accordance with the present invention; 
         FIG. 2  is a partially plan view and partially cross sectional view of a guidewire converter in accordance with the present invention; 
         FIG. 3  is a cross-sectional view of a distal end of a guidewire converter in accordance with the present invention taken along section line  3 - 3  of  FIG. 2 ; and 
         FIG. 4  is a detailed cross-sectional view of an inner guidewire locking mechanism in accordance with the present invention taken from area  4  of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 and 2 , convertible guidewire  10  of the present invention generally includes guidewire  12  and guidewire converter  14 . 
     Guidewire  12  is a generally conventional guidewire of a diameter smaller than guidewire converter  14  and generally having a length greater than guidewire converter  14 . Guidewire  12  may be any guidewire known to those skilled in the art as well as any sort of guidewire which may be developed following the filing of this application. For example, guidewire  12  may include a 0.014 inch diameter guidewire having a curved or straight end. Guidewire  12  may also include ends that are bent, J-shaped or any other end style known to those skilled in the art. Further, guidewire  12  may be a guidewire of any working diameter as long as it is smaller than guidewire converter  14  as will be seen. 
     In this example, guidewire converter  14  generally includes distal sleeve portion  16  and locking portion  18 . 
     Referring to  FIGS. 1 ,  2  and  3 , an example embodiment includes liner  20 , less rigid portion  22 , more rigid portion  24  and tapered distal end  26 . Distal sleeve portion  16  generally includes tapered distal end  26 . Marker band  28  may be located proximate to tapered distal end  26 . Marker band  28  may be formed of a radiopaque substance such as platinum iridium that is highly visible to x-ray imaging. Both more rigid portion  24  and less rigid portion  22  are flexible. However, less rigid portion  22  generally has greater flexibility that does more rigid portion  24 . 
     Liner  20  may be formed of, for example, PTFE/polyimide. Liner  20  covers the interior of guidewire converter  12 . More rigid portion  24  may be formed from a polymer material, for example, nylon 12. Less rigid portion  22  may be formed of, for example, Pebax having a Shore hardness of 55d. Less rigid portion  22  may extend, for example, for about 20 centimeters from taper distal end  26 . 
     More rigid portion  24  generally extends from the end of less rigid portion  22  to locking portion  18 . This length will be variable because guidewire converter  14  can be made in a variety of different lengths. For example, guidewire converter  14  may be made in overall lengths of 80 centimeters, 120 centimeters and 145 centimeters. These lengths are examples only and should not be considered to be limiting. 
     Distal sleeve portion  16  may be externally coated with hydrophilic coating  30 . Hydrophilic coating  30  may extend for example, for about 40 centimeters proximally from tapered distal end  26 . 
     In an example embodiment, intended for use in combination with a 0.014 inch diameter guidewire  12 , guidewire converter  14  may have an outside diameter of 0.0350 inches and an inside diameter of 0.0175 inches. 
     Referring to  FIGS. 1 ,  2  and  4 , locking portion  18  has a maximum outside diameter no greater than the outside diameter of distal sleeve portion  16 . For example, in an example embodiment, if distal sleeve portion  16  has an outside diameter of 0.0350 maximum then locking portion  18  has a maximum outside diameter of 0.0350 inches or less as well. 
     In an example embodiment, locking portion  18  includes collet  32 , tapered tube  34  and inner locking sleeve  36 . Collet  32  may, for example, include three fingers  38  formed by cutting three slots  40  into locking sleeve  36 . Inner locking sleeve  36  has an outside diameter smaller than that of tapered tube  34  and distal sleeve portion  36 . Locking sleeve  36  may be formed for example of 304 stainless steel, another biocompatible metal or a rigid polymer material. 
     Tapered tube  34 , in an example embodiment, includes cylindrical portion  42  and tapered portion  44 . Tapered tube  34  is dimensioned so that when collet  32  is moved into tapered portion  44  from cylindrical portion  42 , collet  32  is forced radially inwardly to secure guide wire converter onto guidewire  12 . 
     Guidewire converter  10  defines lumen  48 . Lumen  48  is sized to receive guidewire  12 . 
     The present invention also includes a method of providing a medical device including providing guidewire converter  14  along with instructions for its use. Providing the device includes sale directly on indirectly to a user, importing or exporting the device as well as giving the device to a user without payment. The providing of instructions includes providing instruction in writing or verbally as well as presentation of the instructions in a seminar in person, through a computer network or by telephone or video communication. 
     In operation when it is desired to convert a guidewire between two different sizes, a physician may make use of convertible guidewire  10  of the present invention. This description may refer to conversion between a 0.014 diameter guidewire and a 0.035 diameter guidewire, however, this is not intended to be limiting. Conversion may take place between any larger and smaller guidewire sizes in the context of the present invention. 
     For example, a physician may insert guidewire  12  inserted inside guidewire converter  14  into a blood vessel in the body. When it is desired to convert from the larger size guidewire to a smaller size guidewire, the physician may actuate locking portion  18  to release guidewire converter  14  from guidewire  12 . Guidewire converter  10  is then removed over guidewire  12 . 
     In one embodiment of the present invention, locking sleeve  36  is slid distally over collet  32  to release three fingers  38  from their grip on guidewire  12 . Then guidewire  12  may be held in place while guidewire converter  14  is withdrawn over the top of guidewire  12 . 
     Perhaps more commonly, a physician will wish to use convertible guidewire  10  to enlarge a smaller guidewire that has already been placed. In this circumstance guidewire  12  is pre-placed within a blood vessel. When it is desired to enlarge guidewire  12 , convertible guidewire  10  is applied by placing the proximal end of guidewire  12  inside tapered distal end  26  of guidewire converter  14 . Guidewire converter  14  is then advanced over guidewire  12  until the physician has positioned tapered distal end  26  of guidewire converter  14  at a desired location. The presence of marker band  28  facilitates the positioning of tapered distal end  26  by making tapered distal end  26  visible to fluoroscopy or ultra sound. 
     Once the physician has positioned guidewire converter  14  as desired, the physician may apply locking portion  18  to secure guidewire converter  14  to guidewire  12 . 
     In order to do so, the physician grasps locking sleeve  36  and advances it toward the distal end of guidewire converter  14  a short distance. As locking sleeve  36  is advanced, three fingers  38  of collet  32  are comprised about guidewire  12  as three fingers  38  transition from cylindrical portion  42  to tapered portion  44  of tapered tube  34 . 
     The invention may be embodied in other specific forms without departing from the spirit of the essential attributes thereof, therefore, the illustrated embodiments should be considered in all respects as illustrative and not restrictive, reference being made to the appended claims rather than to the forgoing description to indicate the scope of the invention.