Abstract:
The invention is directed to a hand held vibration device which imparts reciprocating motion in a guidewire while leaving the guidewire free to rotate about its longitudinal axis, to facilitate advancement of the guidewire through a highly occluded blood vessel. The vibrating device is provided with a lock ring for reversibly preventing guidewire rotation without effecting guidewire reciprocation, and the reciprocation length of the device may be varied. The length the guidewire extends past the distal end of a delivery catheter may be varied from controls on the device which do not require guidewire detachment from the reciprocating mechanism. The device may be used with or without a delivery catheter provided with a curved distal end, the curvature of which can be varied while the catheter is inside the patient.

Description:
This application is a division of Ser. No. 08/822,150 filed Mar. 17, 1997 U.S. Pat. No. 5,908,395. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to the field of medical devices, and more particularly to a guidewire system for advancement through a highly occluded blood vessel. 
     Atherosclerosis resulting in a blockage of arteries can be a life threatening disease. Percutaneous intravascular procedures such as angioplasty and atherectomy were developed to open blocked vessels with as little trauma as possible. Angioplasty involves inflating a balloon positioned within the obstructive deposits or stenosis in the vessel, so that the stenosis is compressed against the arterial wall and the wall expanded to open up the passageway. Atherectomy involves selective excision and removal of obstructive deposits from the vessel walls. 
     An essential first step in these percutaneous procedures is maneuvering the distal operative extremity of the angioplasty or atherectomy catheter into position at a precise point inside the arterial occlusion. Maneuvering through small branched vessels and the stenosis itself can be very difficult and tedious. Especially difficult in this respect are chronic total occlusions (CTO). While most CTOs are not totally obstructed, only a small tortuous channel passes through the stenosis. 
     The guidance system used to position the catheters must be both effective and safe, because if they cannot be positioned precisely into place, the stenosis cannot be treated. Additionally, inadequate guidance carries a risk of perforation of the vessel that exceeds the benefits of recanalization. 
     The use of a guidewire is ideal in terms of effectiveness, safety, simplicity, and cost. Typically, a guiding catheter is inserted into the patient&#39;s aorta with its distal tip seated in the ostium of the desired coronary artery. The guidewire is then maneuvered into place while its progress is fluoroscopically monitored. Once the guidewire passes through the stenosis, the angioplasty or atherectomy catheters can be advanced over the guidewire and into place within the stenosis. 
     The distal end of the guidewire-may be shaped, e.g. bent, at an angle up to 90° from its longitudinal axis, so that torquing the proximal end of the guidewire from outside the patient can guide the distal tip of the guidewire into branch arteries. While it is known that vibrating a guidewire can help its passage through an occluded artery, such vibration has not been shown to be successful in highly occluded passageways such as CTO&#39;s. 
     What has been needed is a vibration device with the superior guidewire steerability and ease of use which results from having the guidewire free to rotate or move longitudinally relative to the distal tip of a guiding catheter even though the guidewire is attached to the vibrating mechanism. By providing for simultaneous manipulation of more than one variable of the guidewire, such a device gives the operator greater control over the guidewire position. Furthermore, such a device would have superior ease of use because unclasping, repositioning, and reclasping the guidewire to the vibration mechanism would not be required each time the guidewire needed to be rotated or moved relative to the guiding catheter. 
     Additional guidewire control would be provided by a guiding catheter with a bend in the distal tip which could be varied incrementally from 0° to 90° from its axis, while the catheter was inside a patient vessel. When attached to a vibrating device, a catheter with such in situ variability would allow the distal end of the guidewire to oscillate at a variety of angles to the longitudinal axis of the catheter, and would be useful in accessing off-center channels and side branches. 
     The vibration device of the present invention provides such a combination of desirable properties. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a guidewire vibration device for use with or without a guidewire guiding catheter, to aid in advancement of a guidewire through a patient vessel. The vibration device of the invention generally has a guidewire tube reciprocally driven by a motor, designed to provide superior steerability in a reciprocating guidewire. 
     The vibration device has a housing, an electric motor within the housing, and a cam attached to the motor which translates the motor&#39;s rotational output into repetitive linear motion. A reciprocating member attaches to the cam to vibrate with a pivoting action. A tube is attached to the reciprocating member so that the tube reciprocates with the reciprocating member along the tube&#39;s longitudinal axis but remains free to rotate around the longitudinal axis. A suitable connection is a ball and socket joint formed by a ball on the tube which fits into a socket on the reciprocating member. A guidewire threads through the lumen of the tube, and is releasably attached to the proximal end of the tube. 
     The rotation of the guidewire tube may be unchecked, or a locking mechanism may be used. A suitable locking mechanism reversibly locks the rotational motion of the tube by adjusting the circumference of an opening through which the guidewire tube extends. When narrowed, the opening is large enough to allow the tube to clear when reciprocating longitudinally but too small to allow corners of the tube to clear if tube rotation is attempted. 
     In accordance with a further development of the invention a fitting attaches a guiding catheter to the vibration device. The fitting allows the guiding catheter to be reversibly extended or retracted while in use, thereby varying the length that the guidewire extends beyond the distal tip of the catheter without requiring detachment of the guidewire from the vibration device. A suitable fitting has a rotating luer ring threaded onto a distal side of the device, and a tubular support member with a proximal end attached to the rotating luer ring and a distal end attached to a luer fitting which releasably connects a guiding catheter to the tubular member. Rotation of the luer ring imparts longitudinal movement in the catheter but not in the guidewire. 
     In accordance with a further development of the invention, the vibration device has a variable stroke mechanism that varies the fulcrum of the reciprocating member to vary the reciprocation length. A suitable mechanism has a rotating cap threaded onto the vibration device, and a pivot block attached to the reciprocating member and the underside of the rotating cap. When the cap is rotated, the pivot block is displaced and the fulcrum of the reciprocating member is shifted, thereby varying the angle at which the reciprocating member pivots. 
     In a preferred embodiment, the vibration device may be used in combination with a guidewire guiding catheter that has support characteristics which can be varied while inside the patient&#39;s vessel. The guiding catheter has an outer tubular member and a inner tubular member slidably disposed within the lumen of the outer tubular member. The distal extremity of the inner tubular member is provided with a curved end which can be reversibly straightened by retracting the inner tubular member distal tip into the distal end of the outer tubular member. The inner tubular member is formed of a plastic material having a modulus of elasticity such that the curve at the distal tip straightens under applied force and subsequently returns when the force is removed. The proximal end of the inner tubular member is attached to the vibration device in a position to receive the guidewire. 
     The vibration device of the invention provides for ease of use and superior control in advancing a guidewire through a patient vessel. This is due to the ability to rotate the guidewire and vary the length that the guidewire extends beyond the distal tip of the guiding catheter, while the guidewire is still attached to the vibrational mechanism. With prior devices the guidewire could not be manipulated independently of the vibration device, so the operator would have to loosen the clamping mechanism that holds the guidewire to the vibration mechanism, reposition the guidewire, and then reclamp the guidewire to the vibration mechanism. Additionally, the guidewire position inside the vessel could not be manipulated very well with the prior devices because the guidewire would not be vibrated simultaneously with the other manipulations such as rotation. Furthermore, the tediousness of repeatedly releasing, repositioning, and reattaching the guidewire to the vibration mechanism adds to operator fatigue and possibly operator error or engagement with an unsterile area thereby requiring the operator to start over from the beginning with a new sterile guidewire. 
     The guidewire steering is further optimized by the use of the guiding catheter with a distal tip angle of curvature which can be varied while inside the patient vessel. By enabling the distal end of the guidewire to oscillate at a variety of angles to the longitudinal axis of the catheter, this in situ variability allows off-center channels and side branches to be accessed which otherwise would have been difficult or impossible to enter. These and other advantages of the invention will become more apparent from the following detailed description of the invention and the accompanying exemplary drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevational schematic view of a guidewire vibration device embodying features of the invention. 
     FIG. 2 is a transverse cross-sectional view of the guidewire delivery catheter shown in FIG. 1 taken along lines  2 — 2 . 
     FIG. 3 is a transverse cross-sectional view of the guidewire delivery catheter shown in FIG. 1 taken along lines  3 — 3 . 
     FIG. 4 is a transverse cross-sectional view of the guidewire delivery catheter shown in FIG. 1 taken along lines  4 — 4 . 
     FIG. 5 is an enlarged longitudinal cross-sectional view of the proximal end of the guidewire delivery catheter shown in FIG.  1 . 
     FIG. 6 is an elevational schematic view of a guidewire delivery catheter configured for manual vibration, illustrating the inner tubular member extending out the outer tubular member. 
     FIG. 7 is an enlarged view of the distal end of the guidewire delivery catheter shown in FIG. 1 illustrating the inner tubular member extending out the outer tubular member. 
     FIG. 8 is an enlarged view of the distal end of the guidewire delivery catheter shown in FIG. 1 illustrating the inner tubular member withdrawn into the outer tubular member. 
     FIG. 9 is a cross-sectional view of the guidewire vibration device shown in FIG.  1 . 
     FIG. 10 is a fragmentary cross-sectional view of the device of FIG. 1 illustrating a reciprocating lever and a pivot block. 
     FIGS. 11 and 12 are transverse cross-sectional views of the rotating lock ring shown in FIG.  10 . 
     FIG. 13 is a fragmentary cross-sectional view of the rotating lock ring shown in FIG. 10 in the unlocked position. 
     FIG. 14 is an elevational schematic view of the device shown in FIG. 1 illustrating the action of the rotating luer ring imparting motion to the delivery sheath. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A guidewire vibration device  10  embodying features of the invention is illustrated in FIG. 1, and generally includes a housing  11  connected to a guidewire tube  12  having a lumen configured to slidably receive a guidewire  13  suitable for advancement through a patient&#39;s coronary and peripheral blood vessels. 
     Referring to FIG. 1, a presently preferred embodiment of the invention includes a delivery catheter  14  which may be attached to the vibration device  10  to facilitate directing the catheter operative end to a desired location. FIGS. 2-4 illustrate transverse cross-sections of the delivery catheter  14  taken along FIG. 1 lines  2 — 2 ,  3 — 3 , and  4 — 4  respectively. The delivery catheter  14  has an outer tubular member  16  and an inner tubular member  17  disposed within the outer tubular member lumen  18 . The inner tubular member  17  has a lumen  19  extending therein which is configured to slidably receive the guidewire  13 . A stiffening rod  20  may be provided within the outer tubular member lumen  18  to add rigidity to the outer tubular member  16 . Strain relief tubing  21  may also be provided for added support at the proximal end of the outer tubular member  16 . An annular space  15  is defined by the part of the outer tubular member lumen  18  existing between the inner  17  and outer  16  tubular members, and may provide a channel for introducing a liquid out the distal end of the catheter. 
     As can be seen in FIG. 1, the outer tubular member  16  may have a radiopaque metal tip marker  22  on its distal end for fluoroscopic observation of the tubular member, and may have printed brachial  24  and femoral  26  markings. The inner tubular member  17  may also have a radiopaque metal tip marker  23  on its distal end. More than one durometer may be spliced together so as to form a variable stiffness catheter (not shown). 
     In the presently preferred embodiment shown in FIG. 5 the inner tubular member  17  is longer than the outer tubular member  16  and extends through a cylindrical member  30 , a hollow support member  31 , and terminates at its proximal end in a centerport adapter stem  32 . Hollow support member  31  can be fixed to centerport adapter stem  32  by any convenient means, e.g., by cementing the two together. The inner tubular member  17  lies inside the hollow support member lumen  33  of the hollow support member  31  which is slidably received in the cylindrical member lumen  34 . The cylindrical member  30  functions in part as a carriage in which the hollow support member  31  and inner tubular member  17  disposed therein are free to move along an axis parallel to the guidewire&#39;s  13  longitudinal axis. The cylindrical member  30  and outer tubular member  16  remain stationary as the inner tubular member, hollow support member  31 , and vibration device  10  move longitudinally. In the embodiment shown in FIG. 5, the cylindrical member  30  is a Y-connector having a hollow side arm  40  for introducing a liquid to the annular space  15  of the outer tubular member lumen  18 . Any suitable connector  36  may be used to connect the cylindrical member  30  distal end to the outer tubular member proximal end directly, or including strain relief tubing  21  connected to the outer tubular member  16 . This allows the inner tubular member  17  to be moved independently of the outer tubular member  16  so that the inner tubular member distal end can be extended and retracted beyond the outer tubular member distal end. 
     The distal end of the hollow support member  31  may have an enlargement  37  which is larger than the port  38  at the proximal end of the cylindrical member  30  which acts as a stop to prevent the hollow support member  31  from fully disengaging from the cylindrical member  30 . While a Touhy-Borst connector  39  is shown in FIG. 5 connecting the hollow support member  31  to the cylindrical member  30 , any suitable connector may be used. FIG. 5 shows a luer connector  42  securing the proximal extremity of the delivery catheter  17  to the vibration device  10 , although any suitable connector may be used. 
     FIG. 6 illustrates the delivery catheter  14  configured for use in manual guidewire vibration, in which case a Touhy-Borst connector  43  is provided in place of the aforementioned luer connector  42  at the proximal extremity of the delivery catheter  14 . 
     The distal end of the inner tubular member  17  has a preformed curve  46  bent at an angle up to 90° from its axis, and the inner tubular member is formed of a flexible plastic material having a modulus of elasticity such that the curve  46  at the distal end straightens under applied force and subsequently returns to its original shape when the force is removed. As shown in FIG. 7, when the inner tubular member  17  is fully extended out the distal end of the outer tubular member  16 , its distal end is curved. FIG. 8 shows that withdrawing the inner tubular member  17  into the outer tubular member  16  straightens the curve at the distal end of the catheter. 
     The extent to which the inner tubular member  17  is extended beyond the distal end of the outer tubular member  16  controls the degree to which the distal end is bent. In a presently preferred embodiment, the inner tubular member  17  is of a length such that it can extend a maximum of about  3  centimeters past the distal end of the outer tubular member  16 . When the inner tubular member  17  is extended or retracted relative to the outer tubular member distal end, the guidewire  13  position relative to the inner tubular member  17  does not change when the guidewire is secured to the vibration device  10 . 
     The delivery catheter  14  may be formed of materials common in delivery catheter design. The inner  17  and outer  16  tubular members may be made of any number of polymeric materials, and the inner and outer tubular members preferably possess a low coefficient of friction with respect to oneanother to facilitate the advancement of the inner tubular member  17  and that of the guidewire  13  as well. An alternative embodiment (not shown) including an outer tubular member made up of a plurality of tube lengths of different diameter, where each proximal tube has a diameter larger than the tube distal thereto so that they may be inserted one into the other, may be used to provide a delivery catheter with variable rigidity. 
     The internal components of the vibration device  10  shown in FIG. 1 are best illustrated in FIGS. 9 and 10. Referring now to FIG. 9, the housing  11  has an interior chamber  50  containing a motor  51  with a rotary output shaft  52 . The motor output shaft  52  turns a cam  53  which travels in an orbital motion. The cam  53  imparts reciprocating motion to a reciprocating member  54 , the guidewire tube  12 , a collet  56 , and a guidewire  13  positioned within the guidewire tube  12  and collet  56 . The reciprocating member  54  generally has a bore  57  to connect with the guidewire tube  12 . The arrangement described protects the guidewire from direct exposure to the electrical components of the system. This guards against current leakage onto the guidewire. 
     A specific embodiment of the invention is illustrated in FIGS. 9 and 10. Referring now to FIG. 10, the reciprocating member  54  is a reciprocating lever  58  which reciprocates the guidewire tube  12 . The reciprocating lever  58  has a first end  59 , a second end  60 , a socket  61 , and a groove  62  in the second end which operatively engages with the cam  53  to translate the cam orbital motion to reciprocating motion. The reciprocating leyer  58  reciprocates about its fulcrum  64 . The socket  61  extends through the reciprocating lever  58  and is sized to mate with an expanded section  63  on the guidewire tube  12 . This allows the guidewire tube  12  to reciprocate with the reciprocating lever  58  while remaining free to rotate around the guidewire tube longitudinal axis. The socket  61  is shown in dashed lines in FIG. 10 to better illustrate the expanded section  63  on the guidewire tube  12 . 
     Illustrated in FIGS. 10-13 is a rotating lock ring  70  which attaches to a first externally threaded cylindrical extension  71  on the housing  11  and which can be rotated to prevent the guidewire tube  12  from rotating about its longitudinal axis. The rotating lock ring  70  is best shown in FIG.  13  and has a plurality of arms  72 , having outer sides  73  and inner sides  74 , which extend diagonally down into the core  76  of the lock ring  70  to form an opening  77  through which the guidewire tube  12  extends. A boss  78  having an inner face  79  is provided on the housing  11 , and when the lock ring  70  is rotated and moved into the locked position the inner face  79  of the boss  78  contacts the outer sides  73  of the arms  72 , forcing the arms inward and narrowing the opening  77  formed by the arms  72 . FIG. 10 shows the rotating lock ring  70  in a locked position in which the guidewire tube  12  will contact the arms  72  if rotation is attempted but remains free to reciprocate longitudinally through the opening  77 . FIG. 13 shows the rotating lock ring  70  in the unlocked position in which the arms  72  are not in contact with the boss  78 . The material used for the arms  72  should be such that bending of the arms  72  when in the locked position does not exceed the elastic limit of the material so that they will not permanently deform when in the locked position. 
     FIG. 12 shows, a cross-sectional view of the rotating lock ring  72  along lines  12 — 12  in FIG. 10, and illustrates a most preferred embodiment having four arms forming a square opening through which a guidewire tube  12  having four flat sides extends. Other lock ring configurations which reversibly alter the opening through which the guidewire tube  12  extends may be suitable. For example a lock ring with an axis offset from the guidewire tube&#39;s axis and with an opening that is circular with two flat sides meeting to form an angle of about 90°, will allow guidewire tube rotation when the guidewire tube is close to the circular region of the opening but prevent it when rotation of the lock ring moves the flat sides closer to the guidewire tube (not shown). 
     Referring again to FIG. 10, a rotating cap  81  may be provided which is threaded onto the housing  11  of the vibration device which may be used to change the stroke length of the reciprocating lever  58 . The rotating cap  81  is attached to a pivot block  82  and cap rotation imparts linear motion to the pivot block. The pivot block is attached to the reciprocating lever  58  at a point of contact which varies as the rotating cap  81  is rotated and the pivot block  82  is linearly displaced. This point of contact is the fulcrum  64  on which the reciprocating lever  58  reciprocates so the rotating cap  81  and pivot block  82  together change the stroke length of the reciprocating lever  58  by changing the lever&#39;s fulcrum  64 . 
     FIG. 10 best illustrates a rotating luer ring  90  which attaches to a second externally threaded cylindrical extension  91  on the housing  11  and which can be rotated to impart longitudinal motion in the guidewire delivery catheter  14  along an axis parallel with the guidewire longitudinal axis without imparting rotational or longitudinal motion to the guidewire  13 . The guidewire  13  is slidably received in the lumen  92  of a tubular support member  93  attached to the rotating luer ring  90  and a luer fitting  94 . A guidewire delivery catheter  14  may be attached to the device  10  at the luer fitting  94 , and rotating the luer ring  14  imparts longitudinal motion in the tubular support member  93 , the luer fitting  94 , and the delivery catheter  14 , but not in the guidewire  13  positioned within the delivery catheter  14 . FIG. 14 illustrates the action of the rotating luer ring  90  at line  14   a — 14   a , and the maximum distance of adjustment of the delivery catheter position is about 10 millimeters or more. 
     As illustrated in FIG. 1, the housing  11  of the vibration device  10  is sized and shaped to fit comfortably in the operator&#39;s hand. In operation, the button  55  on the housing  11  is pushed to activate the reciprocating member  54 . The guidewire  13  is pushed through a stenotic segment of a vessel as seen in FIG.  1 . The guidewire  13  may be secured to the device at the collet  56  and reciprocated, and it is free to rotate even though it is secured to the device. This freedom to rotate results in a vibration device with superior guidewire steerability and ease of use. A delivery catheter  14  may be extended and retracted relative to the guidewire  13  while the guidewire is secured to the device  10 , and the delivery catheter may have stiffness and distal end curvature configuration that can be varied while the catheter system remains in the patient.