Small flexible liquid core catheter for laser ablation in body lumens and methods for use

Abstract

Embodiments relate to the design and use of a low profile ablation catheter with a liquid core for use in laser ablation removal of arterial plaque blockages to restore blood flow.

What is claimed is: 
     
         1 . A liquid core ablation catheter, comprising:
 an elongate low profile, kink resistant, torqueable, multi-layer catheter tube, comprising:
 a base tubular layer including fluorinated or mostly fluorinated material, 
 a braided layer disposed over an outside surface of the base tubular layer, 
 a over-jacket layer coated over the braided layer and base tubular layer to encapsulate the braided layer, and 
 a thin inner luminal layer of a low IR, U.V. transparent, amorphous fluoropolymer having an index of refraction of less than or equal to about 1.33 disposed on an inside surface of the base tubular layer; 
   an ultraviolet grade output optical window or window assembly sealed to a surface of the catheter tube;   a ultraviolet grade input optical window sealed to a surface of the catheter tube at a proximal end of the catheter tube to create a fluid tight core liquid volume; and   a biocompatible U.V. transparent fluid disposed within and completely filling the core liquid volume formed between an inner surface of the thin inner luminal layer, a proximal surface of the output optical window and a distal surface of the input optical window.   
     
     
         2 . The liquid core ablation catheter of  claim 1  wherein an area ratio of the output optical window to an area of an outer diameter of a distal end of the catheter tube is greater than about 40%. 
     
     
         3 . The liquid core ablation catheter of  claim 1  wherein a material of the base tubular layer comprises FEP or PCTFE. 
     
     
         4 . The liquid core ablation catheter of  claim 1  wherein the core liquid comprises a liquid selected from the group consisting of water, normal saline and Ringers solution. 
     
     
         5 . The liquid core ablation catheter of  claim 1  wherein the thin inner luminal layer is comprised of a single or multiple coatings of an amorphous fluoropolymer selected from the group consisting of Teflon AF 2400®, AF 1601®, Cytop®, and Hyflon AD® dissolved in a solvent such as a Fluorinert. 
     
     
         6 . The liquid core ablation catheter of  claim 1  wherein the thin inner luminal layer is made from a coating solution including a low index of refraction perfluoropolyether oil to improve adhesion, increase the film thickness and lower the over all index of refraction of the inner luminal layer. 
     
     
         7 . The liquid core ablation catheter of  claim 1  wherein the braided layer of the multi-layer catheter tube comprises multiple metal ribbons or round wires braided in a manner to provide kink resistance, adequate torque and pushability for the plastic base tubing layer. 
     
     
         8 . The liquid core ablation catheter of  claim 1  wherein the input optical window comprises a U.V. grade synthetic silica or fused quartz rod that acts as a waveguide input window using an air/silica rod configuration such that an NA of the input window is less than or equal to an NA of the liquid core ablation catheter. 
     
     
         9 . The liquid core ablation catheter of  claim 7  wherein the input optical window extends proximally beyond the multi-layer catheter tube of the system to prevent laser damage to the catheter tube. 
     
     
         10 . The liquid core ablation catheter of  claim 1  wherein the input optical window comprises a U.V. grade optical fiber with a cladding that acts as a fiber optic input window such that an NA of the input optical window is less than or equal to an NA resulting from the core liquid inner luminal layer interface of the liquid core ablation catheter. 
     
     
         11 . The liquid core ablation catheter of  claim 1  wherein the catheter tube, optical windows and U.V. transparent fluid are configured to deliver full ablation energy for typical blockages in arteries including calcified plaque with energy densities substantially equal to or greater than about 14 mJ/mm2 and a repetition rate of up to about 100 Hz. 
     
     
         12 . The liquid core ablation catheter of  claim 1  further comprising a radiopaque marker at a distal end thereof to visualize the end of the ablation catheter in the artery through standard fluoroscopic imaging. 
     
     
         13 . The liquid core ablation catheter of  claim 12  wherein the radiopaque marker comprises a tapered metal housing disposed at a distal end of the liquid core ablation catheter. 
     
     
         14 . The liquid core ablation catheter of  claim 1  wherein the inner luminal layer is made by applying a coating of low index amorphous fluoropolymer solution to an inner luminal surface of the base tubular layer and subsequent removal of a solvent of the solution at temperatures near 100 degrees C. but well below the glass transition temperature (Tg) of an amorphous fluoropolymer of the solution and boiling point of the solvent to prevent damage to lower temperature materials used for the base tubular layer or over-jacket layer. 
     
     
         15 . The liquid core ablation catheter of  claim 1  further comprising an outer diameter sufficient to pass through human arteries and is in the range of about 1 mm to about 2.5 mm. 
     
     
         16 . The liquid core ablation catheter of  claim 1  further comprising a red diode laser beam optically coupled to the liquid core ablation catheter and configured to be emitted from a distal end thereof during a procedure using the liquid core ablation catheter. 
     
     
         17 . The liquid core ablation catheter of  claim 1  further comprising an eccentric guidewire lumen disposed along an outer surface of the catheter which has a distal port disposed proximally from a distal end of the ablation catheter by at least about 5 mm and which has a longitudinal length of at least about 10 cm. 
     
     
         18 . A liquid core ablation catheter, comprising:
 an elongate, low profile, kink resistant, torqueable, multi-layer catheter tube including a thin inner luminal layer of a low IR, U.V. transparent, amorphous fluoropolymer having an index of refraction of less than or equal to about 1.33 disposed on an inside surface of the base tubular layer;   an ultraviolet grade output optical window or window assembly sealed to a distal end of the catheter tube;   an ultraviolet grade input optical window sealed to a proximal end of the catheter tube to create a fluid tight core liquid volume; and   a biocompatible U.V. transparent fluid disposed within and completely filling the core liquid volume formed between an inner surface of the thin inner luminal layer, the output optical window and the input optical window.   
     
     
         19 . The liquid core ablation catheter of  claim 18  wherein an area ratio of the output optical window to an area of an outer diameter of a distal end of the catheter tube is greater than about 40%. 
     
     
         20 . The liquid core ablation catheter of  claim 18  wherein the core liquid comprises a liquid selected from the group consisting of water, normal saline and Ringers solution. 
     
     
         21 . The liquid core ablation catheter of  claim 18  wherein the thin inner luminal layer is comprised of a single or multiple coatings of an amorphous fluoropolymer selected from the group consisting of PFPE oil, Teflon AF 2400®, AF 1601®, Cytop®, and Hyflon AD® dissolved in a solvent such as a Fluorinert. 
     
     
         22 . The liquid core ablation catheter of  claim 18  wherein the catheter tube, optical windows and U.V. transparent fluid are configured to deliver full ablation energy for typical blockages in arteries including calcified plaque with energy densities substantially equal to or greater than about 14 mJ/mm2 and a repetition rate of up to about 100 Hz. 
     
     
         23 . The liquid core ablation catheter of  claim 18  further comprising a radiopaque marker at a distal end thereof to visualize the end of the ablation catheter in the artery through standard fluoroscopic imaging. 
     
     
         24 . The liquid core ablation catheter of  claim 18  wherein the output optical window is secured to the distal end of the catheter tube with a tapered metal housing disposed at a distal end of the catheter tube. 
     
     
         25 . The liquid core ablation catheter of  claim 24  wherein the tapered metal housing comprises a radiopaque marker configured to be visualized under fluoroscopic imaging. 
     
     
         26 . The liquid core ablation catheter of  claim 18  wherein the inner luminal layer is made by applying a coating of low index amorphous fluoropolymer solution to an inner luminal surface of the base tubular layer and subsequent removal of a solvent of the solution at temperatures near 100 degrees C. but well below the glass transition temperature (Tg) of an amorphous fluoropolymer of the solution and boiling point of the solvent to prevent damage to lower temperature materials used for the base tubular layer or over-jacket layer. 
     
     
         27 . The liquid core ablation catheter of  claim 18  further comprising an outer diameter sufficient to pass through human arteries and is in the range of about 1 mm to about 2.5 mm. 
     
     
         28 . The liquid core ablation catheter of  claim 18  wherein the multi-layer catheter tube comprises a total wall thickness less than or equal to about 0.015 inches. 
     
     
         29 . The liquid core ablation catheter of  claim 28  wherein the multi-layer catheter tube comprises a total wall thickness less than or equal to about 0.010 inches. 
     
     
         30 . The liquid core ablation catheter of  claim 29  wherein the multi-layer catheter tube comprises a total wall thickness less than or equal to about 0.008 inches. 
     
     
         31 . The liquid core ablation catheter of  claim 18  further comprising a red diode laser beam optically coupled to the liquid core ablation catheter and configured to be emitted from a distal end thereof during a procedure using the liquid core ablation catheter.