Apparatus and Methods for Coronary Sinus Access

Abstract

An apparatus for imaging a body structure within a body cavity includes a catheter including proximal and distal ends, an imaging element on the distal end, and an extension extending distally from the distal end for contacting a surface of a body cavity into which the catheter is introduced. The extension has a length to maintain the optical imaging element away from the surface. Optionally, a transparent member, e.g., an expandable balloon, may be attached to the distal end of the tubular member and the extension to isolate the imaging element from contact with fluid within the body cavity. During use, the catheter is inserted into a chamber of a beating heart, and the extension and/or balloon is placed against the wall of the chamber. Sufficient force is applied to stabilize the imaging element relative to the wall while the heart is beating.

1 . An apparatus for imaging a body structure within a body cavity, comprising: 
 a flexible tubular member comprising a proximal end, a distal end sized for introduction into a body cavity, and a central longitudinal axis extending between the proximal and distal ends;    an optical imaging element carried by the distal end of the tubular member for imaging beyond the distal end; and    an extension attached eccentrically to the distal end and extending distally from the distal end for contacting a surface of a body cavity within which the distal end of the tubular member is introduced, the extension having a predetermined length to maintain the optical imaging element away from the surface by the predetermined length, thereby at least partially defining a field of view of the optical imaging element.    
     
     
         2 . The apparatus of  claim 1 , further comprising a substantially transparent member comprising a proximal end attached to the distal end of the tubular member and a distal end attached to the extension for substantially isolating the optical imaging element from contact with fluid within the body cavity.  
     
     
         3 . The apparatus of  claim 2 , wherein the substantially transparent member comprises an expandable member that is expandable from a contracted condition to an enlarged condition when fluid is introduced through the tubular member into an interior of the expandable member;  
     
     
         4 . The apparatus of  claim 2 , wherein the substantially transparent member comprises a substantially rigid bulb.  
     
     
         5 . The apparatus of  claim 2 , wherein the substantially transparent member comprises a substantially flat distal surface to facilitate imaging tissue structures beyond the expandable member with the optical imaging element.  
     
     
         6 . The apparatus of  claim 1 , wherein the distal end of the tubular member is exposed such that the optical imaging element contacts fluid within a body cavity within which the distal end of the tubular member is introduced.  
     
     
         7 . The apparatus of  claim 1 , wherein the optical imaging element is disposed away from the central longitudinal axis to minimize obstruction of a field of view of the optical imaging element by the extension.  
     
     
         8 . The apparatus of  claim 7 , wherein the optical imaging element is fixed to the distal end generally opposite the extension.  
     
     
         9 . The apparatus of  claim 1 , wherein the extension comprises a tubular extension, and wherein the tubular member comprises a cannulation lumen extending between the proximal and distal ends, the cannulation lumen communicating with the tubular extension for delivering an instrument through the tubular extension beyond the tubular extension.  
     
     
         10 . The apparatus of  claim 1 , wherein the optical imaging element comprises a plurality of optical fibers.  
     
     
         11 . The apparatus of  claim 10 , wherein the optical imaging element further comprises a lens coupled to the plurality of optical fibers for imaging beyond the extension.  
     
     
         12 . The apparatus of  claim 1 , further comprising a light source carried by the distal end of the tubular member for delivering light beyond the extension.  
     
     
         13 . A method for imaging structures within a body cavity, comprising: 
 inserting a distal end of a tubular member into a body cavity, the tubular member comprising an optical imaging element on the distal end and an extension extending distally beyond the distal end and having a predetermined length;    advancing the tubular member until the extension contacts a surface of the body cavity, thereby disposing the optical imaging element away from the surface by a distance corresponding to the predetermined length; and    imaging the surface using the optical imaging element.    
     
     
         14 . The method of  claim 13 , further comprising manipulating the tubular member to move the extension along the surface while continuing to image the surface using the optical imaging element.  
     
     
         15 . The method of  claim 13 , wherein the body cavity comprises a chamber of a beating heart, and wherein the tubular member is advanced with sufficient force to maintain the extension in substantially continuous contact with the surface while the heart is beating, thereby substantially stabilizing the optical imaging element relative to the surface.  
     
     
         16 . The method of  claim 13 , wherein the tubular member comprises a substantially transparent member extending between the distal end and the extension, the method comprising placing a distal surface of the substantially transparent member against the surface to facilitate imaging of the surface using the optical imaging element.  
     
     
         17 . The method of  claim 16 , wherein the substantially transparent member comprises an expandable member, the method further comprising expanding the expandable member within the body cavity before placing the distal surface of the expanded expandable member against the surface.  
     
     
         18 . The method of  claim 16 , wherein the substantially transparent member is substantially transparent to infrared light, and wherein the optical imaging assembly images using infrared light.  
     
     
         19 . The method of  claim 13 , wherein the surface is imaged to identify one or more tissue structures in or extending from the surface.  
     
     
         20 . The method of  claim 19 , wherein the one or more tissue structures comprises a coronary sinus ostium.  
     
     
         21 . A method for imaging a wall of a body cavity of a patient, comprising: 
 inserting a distal end of a tubular member into the body cavity, the tubular member comprising a substantially transparent member extending from the distal end;    placing a distal surface of the substantially transparent member against a surface of the body cavity in order to image the surface through the substantially transparent member using an optical imaging element on the distal end; and    applying sufficient force to maintain the distal surface in substantially continuous contact with the surface of the body cavity for substantially stabilizing the optical imaging element relative to the surface.    
     
     
         22 . The method of  claim 21 , further comprising manipulating the tubular member to move the substantially transparent member along the surface while imaging the surface through the substantially transparent member.  
     
     
         23 . The method of  claim 21 , wherein the distal surface of the substantially transparent member is maintained a predetermined distance from the optical imaging element to maintain the optical imaging element away from the surface being imaged.  
     
     
         24 . The method of  claim 21 , wherein the body cavity comprises a chamber within a beating heart and wherein sufficient force is applied to maintain the distal surface in substantially continuous contact with the surface while the heart is beating, thereby substantially stabilizing the optical imaging element relative to the surface.  
     
     
         25 . The method of  claim 21 , further comprising the tubular member to align a body lumen extending from the body cavity within a field of view of the optical imaging element, thereby substantially aligning a channel through the substantially transparent member with the body lumen.  
     
     
         26 . The method of  claim 25 , further comprising advancing an instrument through the channel into the body lumen after the channel is substantially aligned with the body lumen.