Balloon catheter with enhanced locatability

Abstract

A balloon catheter for insertion in a vessel includes a catheter shaft and an inflatable balloon attached to the catheter shaft. Markings along a longitudinal axis of the catheter are provided in an interior of the balloon, such as for measuring a distance within the vessel. A first distance separating a first marking from a second adjacent marking may be different from a second distance separating the second marking from a third adjacent marking. The markings may also be used for ensuring the proper positioning of the balloon and, in particular, the working surface thereof, relative to a treatment area. Related methods are also disclosed.

1 . A balloon catheter for insertion in a vessel for treating a treatment area, comprising:
 a shaft;   an inflatable balloon attached to the shaft and having an interior; and   at least three radiopaque markings spaced along a longitudinal axis of the catheter in the interior of the balloon, wherein a first distance separating a first radiopaque marking from a second adjacent radiopaque marking is different from a second distance separating the second radiopaque marking from a third adjacent radiopaque marking;   wherein the balloon includes an uninflated midpoint location and an inflated midpoint location;   the shaft includes at least one radiopaque marking positioned at an offset location relative to the uninflated midpoint location,   whereby on inflation of the balloon, the at least one radiopaque marking substantially aligns with the inflated midpoint location.   
     
     
         2 . The balloon catheter of  claim 1 , wherein the catheter shaft further includes an inner tubular member forming a guidewire lumen, and wherein the inner tubular member comprises the at least three radiopaque markings. 
     
     
         3 . The balloon catheter of  claim 1 , wherein the shaft includes an outer wall having at least one of the first or second radiopaque markings. 
     
     
         4 . The balloon catheter of  claim 1 , wherein the first distance is smaller than the second distance and the first radiopaque marking is distal to the second radiopaque marking, which is distal to the third radiopaque marking along the longitudinal axis. 
     
     
         5 . The balloon catheter of  claim 1 , wherein the at least three radiopaque markings are arranged in a pattern comprising a plurality of adjacent pairs, and wherein the adjacent pairs are alternatingly separated by the first and second distances. 
     
     
         6 . The balloon catheter of  claim 1 , wherein the radiopaque markings are arranged in a pattern comprising adjacent radiopaque markings spaced at progressively larger distances from one another from a distal point on the catheter to a proximal point on the catheter. 
     
     
         7 . (canceled) 
     
     
         8 . The balloon catheter of  claim 1 , wherein the second radiopaque marking corresponds to at least one end of the working surface of the balloon. 
     
     
         9 . The balloon catheter of  claim 1 , wherein the third radiopaque marking on the shaft is provided at a location corresponding to another end of the working surface. 
     
     
         10 . The balloon catheter of  claim 1 , wherein the offset location is spaced from the uninflated midpoint location in a proximal direction. 
     
     
         11 . The balloon catheter of  claim 1 , wherein the offset location is spaced from the uninflated midpoint location in a distal direction. 
     
     
         12 . The balloon catheter of  claim 1 , wherein the offset location is spaced from the uninflated midpoint location a distance approximately 1-15% of a length between a distal end and a proximal end of the balloon in an inflated condition. 
     
     
         13 . The balloon catheter of  claim 1 , further including at least one radiopaque marking external to the interior of the balloon. 
     
     
         14 . The balloon catheter of  claim 13 , wherein the external radiopaque marking is located on the shaft. 
     
     
         15 . The balloon catheter of  claim 13 , further including an outer, tubular shaft forming an inflation lumen for supplying an inflation fluid to the balloon, and wherein the external radiopaque marking is located on the outer tubular shaft. 
     
     
         16 . The balloon catheter of  claim 1 , further including a plurality of radiopaque markings external to the interior of the balloon, wherein the external markings are equidistantly spaced. 
     
     
         17 . The balloon catheter of  claim 1 , further including a plurality of radiopaque markings external to the interior of the balloon, wherein the external markings are irregularly spaced. 
     
     
         18 . The balloon catheter of  claim 1 , wherein the markings comprise bands formed at least partially of a radiopaque material. 
     
     
         19 . A balloon catheter for insertion in a vessel for treating a treatment area, comprising:
 a shaft;   an inflatable balloon attached to the shaft, said inflatable balloon having an interior;   at least three radiopaque markings extending along a longitudinal axis of the catheter and located within the interior of the balloon, wherein a first amount of non-radiopaque material separating a first radiopaque marking from a second radiopaque marking is different from a second amount of non-radiopaque material separating the second radiopaque marking from a third radiopaque marking   wherein:   the balloon includes an uninflated midpoint location and an inflated midpoint location;   the shaft includes at least one radiopaque marking positioned at an offset location relative to the uninflated midpoint location,   whereby on inflation of the balloon, the at least one radiopaque marking substantially aligns with the inflated midpoint location.   
     
     
         20 . (canceled) 
     
     
         21 - 42 . (canceled) 
     
     
         43 . A balloon catheter, comprising:
 an elongated, tubular shaft; and   an inflatable balloon supported by the shaft, the balloon having an uninflated midpoint location and an inflated midpoint location;   wherein the shaft includes at least one first radiopaque marking positioned at an offset location relative to the uninflated midpoint location,   whereby on inflation of the balloon, the at least one first radiopaque marking substantially aligns with the inflated midpoint location.   
     
     
         44 . The balloon catheter of  claim 43 , further including a second radiopaque marking corresponding to at least one end of the working surface of the balloon. 
     
     
         45 . The balloon catheter of  claim 44 , wherein the second radiopaque marking is provided on the balloon. 
     
     
         46 . The balloon catheter of  claim 44 , wherein the second radiopaque marking is provided along a narrowed end section of the balloon adjacent one end of the working surface. 
     
     
         47 . The balloon catheter of  claim 44 , wherein the second radiopaque marking is provided on the shaft at a location corresponding to one end of the working surface. 
     
     
         48 . The balloon catheter of  claim 44 , further including a third radiopaque marking on the shaft at a location corresponding to another end of the working surface. 
     
     
         49 . The balloon catheter of  claim 44 , wherein the radiopaque marking or markings comprise a band formed at least partially of a radiopaque material. 
     
     
         50 . The balloon catheter of  claim 44 , wherein the offset location is spaced from the uninflated midpoint location in a proximal direction. 
     
     
         51 . The balloon catheter of  claim 44 , wherein the offset location is spaced from the uninflated midpoint location in a distal direction. 
     
     
         52 . The balloon catheter of  claim 44 , wherein the offset location is spaced from the uninflated midpoint location a distance approximately 1-15% of a length between a distal end and a proximal end of the balloon in an inflated condition. 
     
     
         53 . The balloon catheter of  claim 44 , in combination with a second balloon catheter including a second offset radiopaque marking substantially matching the location of the first radiopaque marking. 
     
     
         54 - 65 . (canceled)