Abstract:
The present invention relates to a medical device including two parallel tubes attached to each other, one of which is shorter in length and receives a guide snare for directing the path of the catheter within a patient&#39;s blood vessels and into the patient&#39;s heart. The present invention further relates to a method of using a catheter comprising two tubes, whereby a guide snare is anchored to a shunt within a patient&#39;s heart and extends out of the patient&#39;s body, one of the tubes of the catheter being placed about the guide snare and the catheter being advanced into the patient&#39;s heart along the guide snare.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to medical catheters for performing diagnostic procedures and other intervention procedures using a catheter placed into a patient&#39;s body.  
         BACKGROUND OF THE INVENTION  
         [0002]    The placing of artificial shunts or other durable passageways in the heart wall to connect heart chambers containing oxygenated blood with coronary arteries is known. These devices and the techniques for placing them in the heart are described in detail in U.S. Pat. No. 5,944,019, issued Aug. 31, 1999, which is hereby incorporated by reference. Collectively, in this application, these devices, including artificial shunts and other durable passageways will be referred to solely as shunts. Such shunts typically are placed in the wall of the heart to allow oxygenated blood to flow into a partially or completely occluded coronary artery as an alternative to more traditional or conventional vein graft coronary arterial bypass procedures. What is needed are effective techniques for accessing the shunts for diagnostic reasons or other reasons.  
         SUMMARY OF THE INVENTION  
         [0003]    The present invention relates to a diagnostic catheter including two parallel tubes attached to each other, one of which is shorter in length and receives a guide snare for directing the path of the catheter to a location within a patient&#39;s body. The present invention further relates to a method of using a catheter comprising two tubes, whereby a guide snare is anchored to a shunt within a patient&#39;s heart and extends out of the patient&#39;s body, one of the tubes of the catheter being placed about the guide snare and the catheter being advanced into the patient&#39;s heart along the guide snare.  
           [0004]    A variety of advantages of the invention will be set forth in part in the description that follows, and in part will be apparent from the description, or may be learned by practicing the invention. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]    The accompanying drawings, which are incorporated in and constitute a part of the description, illustrate several aspects of the invention and together with the description, serve to explain the principles of the invention. A brief description of the drawings is as follows:  
         [0006]    [0006]FIG. 1 is a view of a distal end of a catheter according to the present invention.  
         [0007]    [0007]FIG. 2 is a cross-sectional view of the distal end of the catheter in FIG. 1.  
         [0008]    [0008]FIG. 3 is a schematic illustration with a heart in partial cutaway of a guide snare extending through a femoral artery into the left ventricle of a patient.  
         [0009]    [0009]FIG. 4 is a close up view of the heart of FIG. 3, showing the guide snare within the left ventricle of the patient anchored to a stent in the heart wall.  
         [0010]    [0010]FIG. 5 is a view of a distal end of the catheter of FIG. 1 within the left ventricle of the heart of FIG. 4.  
         [0011]    [0011]FIG. 6 is a view of a heart of in partial cutaway with a distal end of a guide snare within the left ventricle of the heart.  
         [0012]    [0012]FIG. 7 is a view of the heart in FIG. 6 with a guide snare including a distal end anchor extending from the distal end of the catheter.  
         [0013]    [0013]FIG. 8 is a view of an alternative catheter according to the present invention.  
         [0014]    [0014]FIG. 9 is a view of an alternative catheter according to the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0015]    Reference will now be made in detail to exemplary aspects of the present invention which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.  
         [0016]    Cardiac catheterization is the process of inserting a catheter, typically through a major blood vessel, such as a femoral artery  12 , into a heart  26  of a patient. Cardiac stenting is the process of providing a stable passage in the form of a stent or shunt  30  through heart wall  32  for blood to flow out of a chamber, such as left ventricle  22 , of heart  26  into a coronary artery, such as left anterior descending coronary artery  38 . Cardiac catheterization via a femoral artery is may be used to position a diagnostic catheter, such as catheter  100  within heart  26  proximate shunt  30 . Other methods of cardiac catheterization for diagnostic purposes may be found in jointly owned and copending application entitled, Interventional Diagnostic Catheter and A Method for Using a Catheter to Access Artificial Cardiac Shunts, filed Aug. 15, 2001, Attorney Docket No. 11587.34US01, which is incorporated herein by reference.  
         [0017]    Referring now to FIGS. 1 and 2, a catheter  100  is shown including a diagnostic tube  102  and a guide tube  104 . Diagnostic tube  102  is a hollow tube and includes a distal end  106  having one or more openings  108  allowing fluid communication with an interior space  110 . Alternatively, distal end  106  may have an open end or may incorporate a basket. Attached to diagnostic catheter  102  proximate distal end  106  is guide tube  104 . Guide tube  104  is also a hollow tube having an interior passageway  112  extending from distal end  114  to proximal end  116 . Length of guide tube  104  is between 2.5 cm and 8 cm, preferably 8 cm. The length of guide tube  104  will depend on the flexibility of the material from the which guide tube  104  is formed and sharpness of the bends about which the tube will be directed. The diameter of guide tube  104  is sufficient to have an inner diameter that will accept and slide along a guide snare  130 , as shown below. Commonly, these snares are approximately  4  French in size. As shown, distal end  114  and proximal end  116  of guide tube  104  may be flat-faced, or more have a truncated conic shape to aid insertion through blood vessels and heart valves.  
         [0018]    Length of diagnostic catheter  102  is sufficient to allow the insertion of distal end  106  into heart  26 , as shown below, such that hub  120  located proximate proximal end  118 , remains outside of the patient&#39;s body. The desired length may vary based on the entry site of the catheter into the patient&#39;s blood vessels and the physical size of the patient. Hub  120  is adapted to allow tools, such as snares, or diagnostic fluids, such as radio-opaque dyes, to be injected into interior  110  to flow out openings  108  into left ventricle  22 .  
         [0019]    As shown, guide tube  104  may be an integral part of diagnostic tube  102 . Alternatively, guide tube  104  may be a separate tube which is bonded or otherwise attached to outer surface  122  of diagnostic tube  102 . Guide tube  104  as shown is a continuous tube so that a guide snare  130  received within interior passageway  112  by inserting distal end  134  into interior passageway openings at distal end  114 .  
         [0020]    Referring now to FIGS. 3 through 5, a guide snare  130  is shown removably attached by an anchor  132  to an end of shunt  30  extending into left ventricle  22 . Guide snare  130  enters a femoral artery  10  at an insertion site  12  in a patient&#39;s groin. From there, guide snare  130  extends up descending aorta  16  over aortic arch  18  and into ascending aorta  20 . Passing through ascending aorta  20 , guide snare  130  crosses aortic valve  24  to enter left ventricle  22 . At the distal end of guide snare  130  is anchor  132  which releasably holds guide snare  130  to shunt  30  within left ventricle  22 . Shunt  30  provides a stable passageway for oxygenated blood to travel from within left ventricle  22  through heart wall  32  directly into coronary artery  38 . Guide snare  130  can be directed placed on shunt  30  through the use of a guide catheter  43 , discussed below and such as that disclosed in jointly owned and co-pending application entitled, Interventional Diagnostic Catheter and A Method for Using a Catheter to Access Artificial Cardiac Shunts, filed Aug. 15, 2001, Attorney Docket No. 11587.34US01, which is incorporated herein by reference.  
         [0021]    With guide snare  130  in place within left ventricle  22 , diagnostic tube  102  can be advanced into left ventricle  22 , with distal end  106  positioned proximate shunt  30 . To accomplish this, guide snare  130  is inserted within interior opening  112  of guide tube  104 . This insertion may be accomplished by threading proximal end  134  of guide snare  130  through distal end  114  of guide tube  104  and extending guide snare  130  through proximal end  116 .  
         [0022]    [0022]FIG. 4 shows guide snare  130  releasably attached to shunt  30  by anchor  132  at the distal end of guide snare  130 . In this position, guide snare  130  may be used as a guide for directing other tools or diagnostic devices such as catheter  100  into left ventricle  22 , such that the distal end of such a device may be located proximate shunt  30 . FIG. 5 shows guide tube  104  positioned about guide snare  130  within left ventricle  22 . With guide tube  104  is located proximate distal end  106  of diagnostic tube  102 , advancing guide tube  104  toward anchor  132  carries distal end  106  to a location proximate shunt  30 . Alternatively, distal end  106  of catheter  100  may be advanced along guide snare  130  and directed into shunt  30 , or placed over shunt  30  if distal end  106  comprises a bracket. In this position, material may be inserted through hub  120 , into interior space  110  of diagnostic tube  102  and into left ventricle  22 . The material injected may include but not be limited to radio-opaque dyes to aid cardiac imaging to determine blood flow through shunt  30  into coronary artery  38 .  
         [0023]    Referring now to FIGS. 3 through 7, a method of positioning diagnostic catheter  100  within left ventricle  22  is shown. The reach this position, an alignment catheter  43  is inserted at insertion site  12  in femoral artery  10  in a patient&#39;s groin. Alignment catheter  43  is then advanced retrograde through femoral artery  10 , descending aorta  16 , over aortic arch  16 , and through ascending aorta  20 , similar to the path of guide snare  130  shown in FIG. 3. Distal end  45  of alignment catheter  43  is then advanced through aortic valve  24  to arrive at a position within the left ventricle shown in FIG. 6.  
         [0024]    Alignment catheter  43 , as disclosed in jointly owned and co-pending application entitled, Interventional Diagnostic Catheter and A Method for Using a Catheter to Access Artificial Cardiac Shunts, filed Aug. 15, 2001, Attorney Docket No. 11587.34US01, which is incorporated herein by reference, is a hollow catheter allowing items from within the catheter to be passed out distal end  45 . In FIG. 7, distal end  134  of guide snare  130  with anchor  132  is extended beyond distal end  45  into left ventricle  22 . Anchor  132  shown is a simple lasso-type snare. Alternatively, other known snare types suitable for releasably attaching to shunt  30  and anchoring guide snare  130  may be used. Anchor  132  is then extending to lay about shunt  30 . Anchor  132  is then drawn snugly about shunt  30  to secure guide snare  130  within left ventricle  22 . Alignment catheter  43  can then be withdrawn from heart  26  and from the patient&#39;s body, leaving guide snare  130  anchored to shunt  30 , as shown in FIGS. 3 and 4.  
         [0025]    Alternatively, guide tube  104  may include a lengthwise split  124 , extending from distal end  114  to proximal end  116 , split  124  being normally closed. Guide tube  104  may then be made of a resilient deformable material that will allow guide snare  130  to be snapped into guide tube  104  at some location closer to insertion site  12  than proximal end  134 . Once guide snare  130  has been inserted into interior  112 , split  124  will return to its normal closed position. This alternative embodiment is shown in FIG. 8. A further alternative embodiment of a catheter  200  according to the present invention is shown in FIG. 9. Catheter  200  includes a first hollow tube  102 , as described above, and a guide ring  204 . Guide ring  204  is attached to first hollow tube  102  proximate distal end  106 , and provides an opening  212  for receiving guide snare  130 . Guide ring  204  also includes a split  224  allowing guide snare  130  to be placed within opening  212  at a location other than distal end  134 .  
         [0026]    Diagnostic catheter  100  may also be used to guide medical instruments to regions of the body other than the heart. Any location within the body providing an adequate support for anchor  132  may be accessed with catheter  100  using the apparatus and methods disclosed herein. It is anticipated that guide tube  14  and guide ring  204  may be adapted to other medical devices for use within a patient&#39;s body beyond the catheters disclosed herein and similar methods may be used to position these devices.  
         [0027]    Having described preferred aspects and embodiments of the present invention, modifications and equivalents of the disclosed concepts may readily occur to one skilled in the art. However, it is intended that such modifications and equivalents be included within the scope of the claims which are appended hereto.