Dilatation Catheter with Enhanced Distal End for Crossing Occluded Lesions

Abstract

A catheter for crossing an occluding lesion with an inflatable balloon and dilating the lesion includes an inner tube that defines a longitudinal axis. The balloon includes a distal section that is bonded to the tube's distal end, a working section, and a conically shaped distal transition section connecting the working and distal section. A plurality of rigid ribs are spaced around the circumference of the balloon near the catheter's distal end. Each rib includes a first elongated portion attached to the balloon's distal section and aligned substantially parallel with the longitudinal axis. A second portion extending from the first portion and at an angle thereto is attached to and lies along the surface of the balloon's distal transition section. The plurality of ribs combine to simulate a stiff, tapered surface that can be wedged into the occluding lesion to create a passageway to cross the lesion with the balloon.

1 . A catheter, the catheter comprising
 a first shaft;   a balloon, the balloon having a deflated state and an inflated state, the balloon comprising:
 a distal section, the distal section being substantially cylindrically shaped when the balloon is in the deflated state and when the balloon is in the inflated state, the distal section being engaged to the first shaft; 
 a distal transition section, the distal transition section being a truncated cone when the balloon is in the deflated state and when the balloon is in the inflated state; and 
 at least one rib, each rib comprising a first portion and a second portion, the first portion being engaged to the distal section of the balloon and the second portion being engaged to the distal transition section of the balloon. 
   
     
     
         2 . The catheter of  claim 1 , the distal section of the balloon having a diameter, the diameter being the same when the balloon is in the deflated state and when the balloon is in the inflated state. 
     
     
         3 . The catheter of  claim 1 , the first shaft having a longitudinal axis, wherein the first portion is aligned substantially parallel with the longitudinal axis and the second portion extends from the first portion and at an angle thereto. 
     
     
         4 . The catheter of  claim 3 , wherein the angle is between approximately fifteen degrees and forty-five degrees (15°-45°). 
     
     
         5 . The catheter of  claim 1 , the first shaft having a longitudinal axis, each rib further comprising a first end and a second end, the first end being radially distanced from the longitudinal axis at a first distance d 1  and the second end being radially distanced from the longitudinal axis at a second distance d 2  with d 2 >d 1 . 
     
     
         6 . The catheter of  claim 1 , wherein each rib is made of a material selected from the group of materials consisting of Liquid Crystal Polymer, Polyphenylene Sulfide and Polyethylene Naphthalate. 
     
     
         7 . The catheter of  claim 1 , each rib being engaged to the balloon by heat bonding. 
     
     
         8 . The catheter of  claim 1 , each rib being engaged to the balloon by an adhesive. 
     
     
         9 . The catheter of  claim 1 , wherein material forming each rib is extruded onto the distal section and the distal transition section of the balloon thereby engaging the rib to the distal section and the distal transition section of the balloon. 
     
     
         10 . The catheter of  claim 1 , the at least one rib being a plurality of ribs. 
     
     
         11 . The catheter of  claim 10 , the plurality of ribs being evenly spaced around a circumference of the balloon. 
     
     
         12 . The catheter of  claim 11 , the plurality of ribs forming a tapered surface of the balloon at all times. 
     
     
         13 . The catheter of  claim 1 , the balloon further comprising a working section, the distal transition section connecting the working section to the distal section, the working section having a shape, the shape being either cylindrical or a truncated cone when the balloon is in the inflated state. 
     
     
         14 . The catheter of  claim 13 , further comprising a proximal transition section and a proximal section, the proximal transition section connecting the working section to the proximal section, the proximal transition section being a truncated cone when the balloon is in the inflated state, and the proximal section being substantially cylindrical when the balloon is in the deflated state and the inflated state. 
     
     
         15 . The catheter of  claim 14 , the proximal section being engaged to the first shaft. 
     
     
         16 . The catheter of  claim 1 , the first shaft defining a lumen, the catheter further comprising a guidewire, the guidewire being positioned within the lumen defined by the first shaft.