Abstract:
Apparatus for opening an obstructed region of a patient blood vessel comprising a catheter and guidewire. The guidewire is of sufficient length to extend from a region outside the patient to the obstructed region. The catheter acts as a guide tube supporting the guidewire for free axial and rotary movement. A power assembly is positioned outside the patient and has an output shaft joined to the guidewire. The power assembly further includes plural motors drivingly interrelated to move the output shaft to impart simultaneous axial reciprocation and rotary reciprocation to guidewire.

Description:
BACKGROUND OF THE INVENTION 
     The subject invention is directed to a catheter system and apparatus for opening a totally or partially occluded blood vessel. 
     In my prior U.S. Pat. Nos. 4,936,845, issued Jun. 26, 1990, for “Catheter System Having Distal Tip For opening Obstructions,” and 5,116,350, issued May 26, 1992, under the same title, I have disclosed methods and apparatus for opening an occluded blood vessel through the use of a catheter with a drive shaft having a distal tip portion that is impinged against the occlusion with an axial or rotary reciprocatory motion. The patents disclose two separate devices, one capable of producing an axially reciprocated movement and the other capable of producing a rotary reciprocal movement. 
     There are numerous other arthrectomy devices for opening vascular obstructions such as the Kinsey catheter disclosed in U.S. Pat. No. 4,749,376. These other prior devices that use rotary rotation all have the common problem of “wrapping” or “twisting” tissue because of the unidirectional rotation. The reciprocal rotation of my device prevents this from happening. 
     In my prior U.S. Pat. No. 4,854,325, issued Aug. 8, 1989, for “Reciprocating Guidewire Method,” I have disclosed the use of a conventional guidewire for use in forming a passageway through a vascular obstruction. This system utilizes a conventional guidewire and catheter which is already in the patient&#39;s vascular system, such as in a coronary artery. This patent discloses a system for reciprocating the guidewire back and forth. 
     It now appears that it would be most desirable if the drive shaft tip or the guidewire tip were subjected to both forms of reciprocation (i.e., axial and rotary) simultaneously. The combined motions seem to produce more efficient and effective opening of the occlusions than either motion performed by itself. 
     SUMMARY OF THE INVENTION 
     The subject invention provides a system and apparatus that produces combined axial and rotary reciprocatory movements of the drive shaft tip or the guidewire tip in an effective, controllable manner. 
     My prior U.S. Pat. Nos. 4,936,845 and 5,116,350, issued Jun. 26, 1990 and May 26, 1992, respectively, are dedicated systems with a single purpose and are meant for use in the larger vessels. The disclosure of these patents are incorporated herein by reference. Briefly, however, the catheter system generally comprises the previously-mentioned drive catheter wire which terminates in a distal tip that can have a variety of known configurations to assist in penetration through obstructions such as plaque in the blood vessel to be opened. Typical designs are shown, for example, in my above-mentioned prior U.S. patents. 
     My prior U.S. Pat. No. 4,854,325, issued Aug. 8, 1989, titled “Reciprocating Guidewire Method” now appears to be the preferred method and will be the method described in detail. The apparatus generally comprises a conventional catheter having a guidewire protruding from the tip of the catheter. The guidewire has a sufficient length to extend from a region outside a patient to the obstructed region. The catheter acts as a guide for free axial and rotary movement. Positioned outside the patient are power means including an output shaft coupled to the guidewire. The power means includes plural motor means for simultaneously axially reciprocating and rotating the guidewire to impart simultaneous axial reciprocation and rotary reciprocation to the guidewire. 
     In addition, and in accordance with a further aspect of the invention, there are means provided for varying the rate of axial reciprocation imparted to the guidewire. Also, it is preferable that the power means includes a first motor for rotating the guidewire and a second motor for axially reciprocating the guidewire. Means are also provided for periodically reversing the direction of rotation of the first motor to produce rotary reciprocation of the guidewire. 
     In its preferred form, the first motor is mounted for reciprocation and the second motor is drivingly connected to cause axial reciprocation of the first motor. 
     As can be seen from the foregoing, a primary object of the invention is the provision of a catheter system and apparatus that can produce combined axial and rotary reciprocatory movements of the guidewire in a manner to facilitate opening of obstructions in a patient&#39;s blood vessels. 
     A further object of the invention is the provision of an apparatus of the type described wherein the rate of axial reciprocation can be readily varied without varying the rate of rotary reciprocation. 
     A still further object is the provision of an apparatus of the general type discussed which is relatively simple to use, and efficient and effective in operation. The use of a guidewire in place of a drive shaft with tip is very desirable. By using a guidewire to do both the axial and rotary reciprocatory movements, no change of catheter or other device is necessary during a procedure. In other words, the angiographic catheter and the guidewire are already in the patient&#39;s vascular system (example: a coronary artery). If the attempted angiographic study or angioplasty is successful, there is no need for additional devices. However, when an obstruction is encountered that cannot be crossed with the conventional catheter and guidewire which is being used in the patient, additional help is needed. Having to remove the catheter and guidewire already in the patient and exchanging it for another system doubles the risk to the patient. 
     With my new system, all you need is to attach the guidewire, which is already in the patient, to the external motorized device in order to impart the axial and rotary reciprocating movements. 
     Another advantage to the new system is in placing the guidewire and catheter at the beginning of the procedure. There are multiple branching vessels in the coronary system. Pushing a guidewire (0.014″ in dia) with a very flexible (“floppy”) tip section is difficult at best. We are talking about a 6 foot long guidewire being pushed through a catheter not much larger than the guidewire itself. The guidewire must also be able to be turned from side to side. Physical things, such as guidewires, at rest tend to remain at rest. However, if the guidewire is in motion such as being moved backward and forward and from side to side in a controlled manner, the guide will be easier to advance when the desired vessel opening is reached. 
     Still other advantages and benefits of the invention will become apparent to those skilled in the art upon a reading and understanding of the following detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention may take physical form in certain parts and arrangements of parts, a preferred embodiment and method of which will be described in detail in this specification and illustrated in the accompanying drawings which form a part hereof, and wherein: 
     FIG. 1 is a pictorial view showing a catheter guidewire system formed in accordance with the preferred embodiment of the invention; 
     FIG. 2 is a view showing a portion of the catheter reciprocating apparatus (a side panel has been removed to show certain details of construction with the wiring omitted); 
     FIG. 3 is a view showing the interior of the apparatus (the wiring is omitted) used for producing rotary reciprocation of the apparatus; and, 
     FIG. 4 is a somewhat diagrammatic showing of the wiring and controls used in the apparatus. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings wherein the showings are for the purposes of illustrating the preferred embodiment of the invention only and not for purposes of limiting same, FIG. 1 shows the overall arrangement of a catheter guidewire system  10  incorporating a power apparatus  20  for producing combined rotary reciprocation and axial reciprocation of a guidewire  12 . The catheter shown is a coronary dilation catheter. The design is widely known and used. The guidewire  12  shown is also of common design used with coronary dilation catheters. At present, the coronary dilation procedure is the most likely to use the simultaneous axial-rotary reciprocating system. 
     The guidewire  12  extends outwardly through a hemostasis valve  14 , which controls blood loss through a Y luer hub  16  configuration which is the proximal part of the coronary dilation catheter  18 . The guidewire enters the straight section of the Y through the entire catheter  18 , through the dilation balloon  22  portion and protrudes beyond the distal tip  24  portion of the coronary dilation catheter. The branching section of the Y which has a luer fitting  26  is used to inflate and deflate the balloon  22  as necessary. 
     Of particular importance to the subject invention, however, is the means by which the guidewire  12  can be subjected to both rotary reciprocation and axial reciprocation through the action of the power unit  20 . In its preferred form, the power unit  20  includes two separate housings  36  and  38 . The housing  36  carries the power means for imparting the axial reciprocation to the drive catheter  12 , whereas the housing  38  carries suitable batteries and control means for producing the reverse of current supplied to one of the motors which imparts the reciprocatory rotary motion in a manner subsequently to be described. For the present, however, attention is directed to FIGS. 2 and 4 which best illustrate the housing  36  and the power means carried thereby. In particular, the housing  36  is a rigid molded plastic housing having a forward end  39  that carries an outwardly and downwardly extending bracket member  40 . The lower end of the bracket member  40  carries a hemostasis valve  14  through which the drive catheter  12  extends. The outer or forward end of the fitting  14  is arranged to receive in a friction fit manner the end of the coronary dilation catheter. 
     Carried within the housing  36  is a conventional direct current rotary motor  44  positioned so that its output shaft  44   a  extends downwardly through the bottom wall  39   a  of the housing  36 . Also contained within the housing  36  is a battery  46  and an on/off slide switch  48  that are connected through a rheostat type DC motor controller  49  in the manner best illustrated in FIG.  4 . This arrangement allows the speed of rotation of the motor output of shaft  44   a  to be selectively varied. 
     The output shaft  44   a  of motor  44  is connected through a crank arm  48  with a slide member  50  carried for reciprocation in suitable guides  52  mounted on the underside of the lower wall  39   a  as best seen in FIG.  2 . These slides are arranged so as to allow free sliding movement of the slide member  50  in directions shown by the arrow upon rotation of the crank  48 . 
     Suspended from the slide plate  50  is a second motor  54 . Motor  54  is also a DC motor and has an output shaft  56  extending therethrough. The output shaft  56  is hollow and provides a path through which the guidewire  12  can extend. At the left-hand end of shaft  56  (as viewed in FIG.  2 ), there is a collet-like member  60  which joins to the shaft with a first portion  58  and has a resilient internal collar portion that is compressed into frictional gripping engagement with the guidewire  12  by an outer nut member  60 . By tightening member  60  on the end portion  58 , the shaft  56  is drivingly engaged with the guidewire  12 . Thus, during rotation of motor  44 , the motor  54  is caused to reciprocate as shown by the arrows imparting a reciprocatory motion to the guidewire  12 . If, simultaneously therewith, motor  54  is driven to rotate member  60 , a simultaneous rotary motion and axial reciprocation is applied to the guidewire  12 . According to the subject invention, means are also provided to cause a reversal in the direction of rotation of the motor  54  so as to impart a reciprocatory rotary motion to member  60  and, in turn, the guidewire  12 . 
     The means used to produce the reversal of current flow to the small DC motor  54  could, of course, be housed in the same housing  36  as houses the main reciprocating drive motor  44 . It is preferred, however, to provide a separate housing  38  for these components. Referring in particular to FIG. 3 and 4, the means used for causing reversal of the motor  54  comprises a DC motor  64  that has its output shaft connected to rotate a cam  66 . As shown in FIG. 3, the motor  64  is connected with the cam  66  through suitable reduction gearing (not shown). The motor  64  is connected with a battery  68  through a manual slide switch  70  as illustrated. 
     Referring again to the cam  66 , this cam is positioned and arranged to rotate and alternately close and permit opening of two separate micro-switches  72  and  74 . The micro-switches  72 ,  74  alternately complete and open circuits from two separate DC batteries  76  and  78  so that there is a constant reversal in polarity of the current supplied through a current source line  80 . A suitable slide-type on/off switch  82  is included in a line  84  which completes the circuit through the micro-switches  72 ,  74 . As shown, the lines  80  and  84  are connected through a standard coaxial plug assembly  90  to wires  92 ,  94 , respectively. These wires, although not shown in FIG. 2, are connected with the motor  54 . As can be appreciated, the rotation of the cam  66  thus supplies current of a constantly reversing polarity to the motor  54  to cause it to rotate in alternate directions. By controlling the speed of rotation of the output shaft of motor  65  or by varying the cam contour, it is possible to vary the duration of rate of rotary reciprocation of the motor  54 . 
     A slide switch  96  is included in line  92  so that the rotary action of motor  54  can be terminated at any desired time. Thus, not only is the system capable of simultaneous axial reciprocation and rotary reciprocation, but it is also possible to operate with either of the two forms of motion alone. That is, by ceasing operation of motor  44 , a simple rotary reciprocation can be imparted through the action of motor  54 . Alternatively, by opening switch  96  and closing switch  48 , the apparatus can be made to only provide an axial reciprocation. 
     The invention has been described with reference to the preferred embodiment. Obviously, modifications and alterations will occur to others upon a reading and understanding of this specification. It is intended to include all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.