Abstract:
The invention provides a catheter, to be used preferably for cardiac diagnostic and interventional procedures, comprising an elongated tubular body having a proximal and a distal end, and at least one lumen extending axially therethrough. A plurality of support members (e.g. wires) extends through the catheter, essentially parallel to its axis, exits the catheter at a defined distance from its distal opening, and is attached at the catheter in proximity to its distal end. Manipulation of these support members leads to their flexing outward or their retraction towards the catheter, providing an adjustable support for the catheter enabling a safer and more secure engagement of the ostia of coronary arteries.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Priority of U.S. Provisional Patent Application Serial No. 60/190,263, filed Mar. 17, 2000, incorporated herein by reference, is hereby claimed. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable 
     REFERENCE TO A “MICROFICHE APPENDIX” 
     Not applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The apparatus of the present invention relates to angiographic catheters or guide catheters for coronary angioplasty or other coronary or vascular intervention. 
     2. General Background of the Invention 
     During percutaneous coronary intervention, guide catheters are advanced from the periphery, usually the femoral artery, into the aorta. The tip of the catheter is positioned in the ostium of a coronary artery. Subsequently, wires, balloon catheters, and other equipment are advanced through the guide catheter into the large epicardial coronary arteries to treat stenotic lesions. 
     A common problem during these procedures is the lack of guide support. As the operator attempts to advance the interventional equipment into the correct position within the coronary circulation, mechanical resistance is frequently encountered. This mechanical resistance may be due to a variety of factors, including but not confined to tortuosity of the target vessel, tight narrowing or calcification of stenoses, or lack of flexibility of the equipment used. This resistance may often have to be overcome by applying increased mechanical push of the equipment. Many guide catheters, however, lack sufficient stiffness to allow this somewhat forceful passing of the interventional equipment, and back out of their ostial position. 
     Operators will typically attempt to tackle this problem through changes of their interventional equipment such as wires or balloons, or through the exchange of their guide catheter for a stiffer or differently shaped model. Prolongation of the procedure with increased radiation exposure to the patient and operators, wasting of interventional equipment, and the abandoning of the type of intervention best suited for an individual lesion in favor of a suboptimal method requiring less guide support are all frequently seen consequences of lack of guide support. Moreover, the repeated, often forceful engagement of a coronary ostium with ill fitted equipment frequently leads to endothelial trauma and at times even to the dissection of the coronary artery. 
     BRIEF SUMMARY OF THE INVENTION 
     The suggested new guide catheter features a plurality of wires, which are contained within the lumen of the catheter, extending from the proximal end of the catheter until its tip. Exit openings lead the wires outside the catheter lumen for a defined distance. Near the distal end of the catheter, the wires re-enter the catheter, and are securely anchored at or within the catheter wall. 
     A second segment of exposure of the wires to the exterior of the catheter is located at its proximal portion, the catheter segment which is not inserted into the patient&#39;s vascular system, and which is manipulated by the operator. Small knobs on the outside of the catheter are connected to the wires at the proximal segment of the catheter. These small knobs connected to the wires allow the operator to advance and retract them, leading to their flexing away from (with advancing movements of the wires) or their repositioning adjacent to the body of the catheter (with retracting movements of the wires) at a defined section near its distal end. The bending out of the wire forms supporting loops, which firmly anchor the distal portion within the aortic root. The knobs located at the proximal portion of the wires allow for their being locked in any position. Adjustment of the degree of extension or retraction of the wires, and thus the size of the distal wire loops, allows for a safe and secure engagement of the distal opening of the catheter within the coronary ostium targeted. 
     There are numerous advantages of the present invention, as listed below. 
     1. There is ample guide support for the pushing of interventional equipment into the coronary circulation, since the guide catheter is backed by its wires against the opposite wall of the aortic root. 
     2. The touching of the wire bends against the aortic root can be used by the operator to better steer the distal opening of the guide catheter through rotational movements. 
     3. Undue engagement of the coronary ostium can be avoided, significantly lessening the risk of proximal ostial trauma of the coronary artery by the catheter tip with possible injury to the ostial endothelium. 
     4. During coronary angioplasty, the ensemble of the wire bends, in fact, allows to reliably disengage the catheter tip from the coronary ostium throughout most of the procedure, providing adequate blood supply into the coronary without the fear of loss of catheter position. 
     5. The risk of loss of coronary wire position, a not infrequent and potentially disastrous event during angioplasty, is substantially lessened due to the secured guide catheter position. 
     6. Less deep engagement and better coronary flow avoid the need for guide catheters with side holes and their inherent disadvantages. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements and wherein: 
     FIG. 1 is a schematic view of a typical catheter in the human aorta. Also shown are the coronary vessels and the major branches of the aorta; 
     FIG. 2 is a schematic view of the aortic arch, the coronary vessels, a catheter, and a balloon catheter and wire assembly, illustrating the problem to be resolved with the present invention; 
     FIG. 3 is a schematic view of parts of the present invention and its method of use in the aortic arch; 
     FIG. 4 is a schematic view of parts of another embodiment of the present invention and its method of use in the aortic arch; 
     FIG. 5A is a schematic view of parts of another embodiment of the present invention; 
     FIGS. 5B-5E are perspective, magnified views of parts of an embodiment of the present invention; 
     FIGS. 6A-6H are perspective, magnified views of the distal portion of one embodiment of the present invention; 
     FIGS. 7A-7C are views of one embodiment of the present invention; 
     FIGS. 8A and 8B are perspective, magnified views of the proximal element of the present invention; and 
     FIGS. 9A and 9B are side views of the proximal and the distal end of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the enclosed drawings, FIGS. 1 and 2 are intended to illustrate the setting in which the present invention is to be used. 
     FIG. 1 shows a schematic overview of anatomical landmarks and technical equipment used in a typical cardiac catheterization procedure. The catheter  1  enters the vascular system at the common femoral artery  2 , follows the course of the aorta  3 , and has been advanced with its distal end  1   b  or tip extending into the aortic root  4 , just above the heart. The distal opening of the catheter engages a coronary artery  5 . Through this catheter  1  or guide catheter, contrast dye is injected, and/or angioplasty equipment is advanced into the coronary system. The epicardial coronary arteries  5 , but not the underlying heart muscle, have been depicted for clarity. 
     Catheter  1  thus provides a single tube or principal tube for conveying a selected fluid (e.g., dye) or a selected device (e.g., angioplasty equipment). 
     FIG. 2 illustrates the problem leading to the design of the present invention. The guide catheter  1  was engaged in the coronary ostium  6 . A thin, flexible angioplasty wire  7  has crossed successfully a stenotic lesion or blockage  8 . The operator now attempts to advance a balloon catheter  9  through the guide catheter  1  and over the wire  7  into the coronary system. However, the angioplasty balloon  10 , and the balloon catheter  9  on which it is mounted, are unable to cross the blockage  8 . Although the operator attempts to push the balloon  10  and the balloon catheter  9  through the blockage, the blockage  8  proves to be too recalcitrant. Thus, instead of crossing the blockage, the pushing of the balloon catheter  9  provides backward thrust and disengages the guide catheter  1  from its engaged position  11  within the coronary ostium  6  to an unstable, disengaged position  12 , following the direction indicated by arrows  13 , with subsequent buckling of the balloon catheter  9  and wire  7  assembly, leading to possible complete disengagement and loss of position of the entire equipment. 
     FIG. 3 shows the new catheter of the present invention designated generally by the numeral  50  in FIG.  3 . Catheter apparatus  50  includes a catheter body  1  that carries a plurality of thin, coated support wires  14 . Wires  14  are movable (as selected by an operator, cardiologist, technician, or operating room nurse) between collapsed and extended positions. In FIG. 3, wires  14  are shown in the extended position, having exited the guide catheter body  1  and form bends around its distal end  1   b  portion. The guide catheter is now securely positioned within the aortic root  4 , allowing the operator to firmly advance any equipment through the guide catheter  1  into the coronary system, without the risk of loss of guide catheter support. A remote actuator that can be manually, grasped by a user at the distal end portion of the body can be provided for moving the support wires  14  between collapsed and extended positions. 
     Extension of the support wires  14  on the side opposite to the coronary ostium  6  engaged will provide enhanced guide support. Extension of the support wires  14  on the ipsilateral side of the coronary ostium will prevent unduly deep engagement with possible endothelial ostial injury. Complete retraction of the wires  14  to the collapsed position would lead to their firm attachment to the catheter body  1  and the supportive loops would disappear (see FIG. 6 b ). 
     FIG. 4 shows a similar schematic view, using two support wires  14  only. This embodiment of the catheter, although simpler than the previous one, will nonetheless reliably prevent loss of guide support. While it cannot prevent undue deep engagement of the coronary ostium through extension of support wires  14  on the ipsilateral side of the ostium engaged, it can lessen the likelihood of this problem through retraction of the contralateral support wires  14  in conjunction with appropriate catheter pre-shaping and inherent bias specifications (moving the tip of the catheter away from the ostium). 
     FIGS. 5A-5F show in more detail the support wires section  23  of catheter body  1 , and the connection of each support wire  14  to the catheter  1  at the distal end  1 B or tip of the catheter  1 . FIG. 5 a  illustrates the wires  14 , having exited the catheter body  1 , and forming supportive bends or loops in an extended position  15 . FIG. 5B shows the same wires  14 , now in a retracted position  16 . The path of the wires  14  within the catheter body  1  is indicated by dotted lines  17  in FIGS. 5A and 5B. 
     FIG. 5C shows in a partial perspective view, how the distal end of these wires  14  could be connected to small anchor bases  18  or receptacles within the catheter wall  19 . The wires  14  have small, transversely positioned or orthogonal end pieces  20  at their tip, as shown in FIG.  5 D. These orthogonal end pieces  20  rest in small axle joint sockets  21 , a connection which allows for rotational or pivotal movements around the central longitudinal axis  20   a  of the orthogonal end pieces  20 . Small longitudinal slits  22  receive the wires  14  from the outside at the distal end  1   a  of the support section  23  of catheter  1 , and into the anchor bases  18 . FIGS. 5E and 5F show lateral partial perspective views of this ensemble, which allows the wires  14  at the site of their distal attachment a high degree of freedom through pivotal movements. 
     FIG. 5F shows how the wires  14 , at the proximal end of the support section  23 , exit through small exit holes  24  from the catheter wall  19 , within which they run through longitudinal wire channels or tracks  25 . It is readily apparent that this path of the support wires  14 , leaving through pre-formed, diagonal exit holes  24  at the proximal end of the support section  23 , and re-attaching to the catheter at the distal end of the support section  23  into axle joint sockets  21  allowing for rotational freedom of the orthogonal end pieces  20 , will lead to an essentially pear-shaped configuration of the support wires in their extended position  15 , as illustrated in FIG.  5 A. Further, the distance d 2  that the extended wire is extended between exit hole  24  and anchor base  18  is preferably greater than the radial distance d 1  between the central axis  23   a  of the support section and the extended position of wire  16 . 
     FIGS. 6 a  and  6   b  show an alternate, somewhat simpler mode of attachment of the wires  14  at the distal end of the support section  23 . As illustrated in FIG. 6 b , the wires  14  are simply anchored within the catheter wall  19  at anchor point  26 . If the inherent stiffness and bias of the wires  14  remains the same throughout the entire support section  23 , and if the angle of the exit holes  24  is the same at the proximal and the distal ends of the support section  23 , the wires  14 , in any of their extended positions  15 , will assume a shape similar to a Gaussian curve, as illustrated in FIG. 6 a . However, simple variations between the angle of the exit holes  24 , or in the inherent wire stiffness along the support section  23 , could bias the wires in their extended positions  15  to assume an infinite variety of other pre-defined shapes, as best suited for the purpose of an individual catheter. 
     As with the embodiment of FIGS. 5 a - 5   f , the wire  14  extends a distance d 4  along catheter support section  23  that is greater than the radial distance d 3  that wire  16  extends away from the central axis  23   a  of support section  23 . 
     FIGS. 6C-6H show cross sectional views of various arrangements of the position of the wire tracks  25  within the catheter wall  19 . The wire tracks  25  could be positioned in reinforced, thickened portions  27  of the catheter wall  19 . Variations of the number of wire tracks  25 , the shape of the thickened portions  27 , and the positioning of the wire tracks  25  are shown. Lastly, a plurality of wires could be run through a designated wire lumen  28  with a proximal and a distal opening (not shown), that could be connected through a side port (not shown), allowing for it to be flushed and aspirated. 
     FIGS. 7A-7C show yet another embodiment of the present invention. Wires  14 , at the distal end of the support section  23  occupied by wires  14 , attach to a small ring  29 , using either of the two attachment arrangements illustrated in FIGS. 5 and 6. Ring  29  fits into circular indentation  30 , with rotational freedom of ring  29  with respect to catheter  1 . The advantages of this arrangement are easily seen in FIG.  7 A. The catheter  1  is securely positioned by wires  14  within the aortic root  4 , preparing to engage the ostium  6  of the left main coronary artery. Torquing movements of the catheter  1  at its proximal end by the operator are now reliably transmitted into the distal opening of  37  the catheter  1  (arrows  31 ), without fear of laceration of the ostium  6  through jerking and unpredictable catheter movements. Once the optimal rotation of the distal catheter tip has been confirmed fluoroscopically, the catheter  1  can be safely engaged into the coronary ostium through manipulations of the wires  14 . As with the embodiments of FIGS. 5A-5F and  6 A- 6 B, each wire  14  preferably extends a distance d 6  along support section  23  that is greater than the distance d 5  that each wire  14  extends away from the central axis  23   a  of support section  23 . 
     FIGS. 8 a  and  8   b  illustrate the proximal ends of wires  14  and the connections of wires  14  to small knobs  32  via small connection pieces  33 . Knobs  32  move parallel to the catheter axis in longitudinal openings  34 . Accordingly, the ensemble of wire  14 , connection piece  33  and knob  32  moves slidably backward and forward. The range of motion is defined by the length  34   a  of the longitudinal openings  34 . Any conventional connection (e.g. the cammed or transversely serrated surface  35  shown in FIG. 8 a ) between the bottom portion of the knobs  32  and the exterior surface of the catheter body  1  can be used to ensure that no longitudinal movements of the wires occur without intentional change of the knob  32  position by the operator. 
     FIGS. 9 a  and  9   b  are side views of the proximal and the distal ends of the present invention, showing the catheter with four support wires, its proximal  36  and its distal  37  openings. 
     Multiple variations of this catheter design could be proposed, including but not confined to running the wires inside or outside the catheter lumen. The wires could also run in a spiral configuration rather than straight, or their advancement could be obtained through a twisting mechanism or any other conventional mechanism, rather than the knobs suggested in the preceding illustrations. 
     The unique new feature of this invention is the fact that guide support problems are overcome through a plurality of coated wires exiting the catheter in proximity to its tip, forming loops of variable sizes, and allowing its secure positioning and the manipulation of angioplasty equipment through the guide catheter without the fear of loss of guide position. An embodiment of this present invention with a single support wire is also proposed. 
     It is important that the wires, at the support section (and thus at their site of exposure to the central circulation), be covered with a special coating preventing the adhesion and aggregation of platelets with subsequent clot formation. Special lubrication (e.g. hydrophilic surface material) of the wire tracks with special fluid suitable to enhance the slidability of the wires and to prevent clot formation would be advisable. 
     The illustrations of this new invention show a Judkins Left catheter, however, multiple other commonly used catheter shapes would also be suitable for this invention, including but not confined to the Judkins Right, the Amplatz, and the Multipurpose catheters. While the advantages of the above described catheter were shown for a guide catheter for coronary intervention, minor modifications of this new catheter design could also be used for other vascular diagnostic or interventional catheters (e.g. for the safe engagement of coronary arteries or bypass grafts with tight ostial stenoses) renal artery catheters, carotid catheters, and other vascular and non-vascular medical catheters. 
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 PARTS 
               
             
          
           
               
                   
                 PART NUMBER 
                 DESCRIPTION 
               
               
                   
                   
               
               
                   
                  1 
                 catheter 
               
               
                   
                  1a 
                 proximal end 
               
               
                   
                  1b 
                 distal end 
               
               
                   
                  2 
                 common femoral artery 
               
               
                   
                  3 
                 aorta 
               
               
                   
                  4 
                 aortic root 
               
               
                   
                  5 
                 coronary artery 
               
               
                   
                  6 
                 coronary ostium 
               
               
                   
                  7 
                 angioplasty wire 
               
               
                   
                  8 
                 blockage 
               
               
                   
                  9 
                 balloon catheter 
               
               
                   
                 10 
                 balloon 
               
               
                   
                 11 
                 engaged position 
               
               
                   
                 12 
                 disengaged position 
               
               
                   
                 13 
                 arrows 
               
               
                   
                 14 
                 support wires 
               
               
                   
                 15 
                 extended wire position 
               
               
                   
                 16 
                 retracted wire position 
               
               
                   
                 17 
                 wire path 
               
               
                   
                 18 
                 internal anchor base 
               
               
                   
                 19 
                 catheter wall 
               
               
                   
                 20 
                 orthogonal end piece 
               
               
                   
                 20a 
                 central axis 
               
               
                   
                 21 
                 axle joint sockets 
               
               
                   
                 22 
                 longitudinal slits 
               
               
                   
                 23 
                 support wires section 
               
               
                   
                 23a 
                 central longitudinal axis 
               
               
                   
                 24 
                 exit holes 
               
               
                   
                 25 
                 wire tracks 
               
               
                   
                 26 
                 anchor point 
               
               
                   
                 27 
                 thickened wall portion 
               
               
                   
                 28 
                 designated wire lumen 
               
               
                   
                 29 
                 ring 
               
               
                   
                 30 
                 circular indentation 
               
               
                   
                 31 
                 arrows 
               
               
                   
                 32 
                 knobs 
               
               
                   
                 33 
                 connection pieces 
               
               
                   
                 34 
                 longitudinal openings 
               
               
                   
                 34a 
                 distance arrow 
               
               
                   
                 35 
                 cammed surface 
               
               
                   
                 36 
                 proximal opening 
               
               
                   
                 37 
                 distal opening 
               
               
                   
                 50 
                 catheter apparatus 
               
               
                   
                 d1 
                 distance arrow 
               
               
                   
                 d2 
                 distance arrow 
               
               
                   
                 d3 
                 distance arrow 
               
               
                   
                 d4 
                 distance arrow 
               
               
                   
                 d5 
                 distance arrow 
               
               
                   
                 d6 
                 distance arrow 
               
               
                   
                   
               
             
          
         
       
     
     The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims.