System for tissue ablation using pulsed laser

Abstract

Systems for enabling delivery of very high peak power laser pulses through optical fibers for use in ablation procedures preferably in contact mode. Such lasers advantageously emit at 355 nm wavelength. Other systems enable selective removal of undesired tissue within a blood vessel, while minimizing the risk of damaging the blood vessel itself, based on the use of the ablative properties of short laser pulses of 320 to 400 nm laser wavelength, with selected parameters of the mechanical walls of the tubes constituting the catheter, of the laser fluence and of the force that is applied by the catheter on the tissues. Additionally, a novel method of calibrating such catheters is disclosed, which also enables real time monitoring of the ablation process. Additionally, novel methods of protecting the fibers exit facets are disclosed.

What is claimed: 
     
         1 . A kit comprising:
 a catheter configured to operatively couple to a laser system, the laser system comprising: a laser source configured to emit a laser beam comprising a beam propagation ratio (M 2 ) greater than or equal to 10; at least one beam splitter to separate the laser beam into a first laser beam and a second laser beam; a first optical element to introduce a temporal delay into the second laser beam; and a second optical element to combine the first laser beam and the temporally delayed second laser beam into a modified laser beam, the modified laser beam comprising a pulse width less than or equal to 25 nanoseconds; and   written instructions for using the catheter to treat a lesion site within a patient by a method comprising the steps of:
 operatively coupling the catheter to the laser system; 
 guiding the catheter to a treatment site comprising the target lesion; and 
 activating the laser system. 
   
     
     
         2 . The kit of  claim 1 , wherein the catheter further comprises an optical fiber. 
     
     
         3 . The kit of  claim 2 , wherein the optical fiber is configured to transmit the modified laser beam. 
     
     
         4 . The kit of  claim 1 , wherein the instructions for using the catheter to treat the lesion site within the patient by the method further comprises the step of advancing the catheter towards the target lesion. 
     
     
         5 . The kit of  claim 1 , wherein the target lesion comprises any of the following: an atheroma, a plaque deposit, or an undesirable material. 
     
     
         6 . The kit of  claim 1 , wherein the instructions for using the catheter to treat the lesion site within the patient by the method further comprises the step of deactivating the laser system. 
     
     
         7 . The kit of  claim 2 , wherein the optical fiber comprises a fiber core of less than 200 microns in diameter. 
     
     
         8 . The kit of  claim 1 , wherein the catheter further comprises a blunt mechanical blade coupled to a catheter distal end. 
     
     
         9 . The kit of  claim 1 , wherein the catheter further comprises an inner blunt mechanical blade coupled to a catheter distal end and an outer blunt mechanical blade coupled to the catheter distal end. 
     
     
         10 . A kit comprising:
 a catheter configured to operatively couple to a laser system, the laser system comprising: a laser source arranged to emit a pulsed laser beam comprising a beam propagation ratio (M2) greater than or equal to 10; and an optical system in optical communication with the laser source, the optical system comprising a plurality of optical elements arranged to: receive the pulsed laser beam, and form, based in part on the pulsed laser beam, a modified pulsed laser beam comprising a pulse width less than or equal to 25 nanoseconds (ns) and at least two temporally separated component parts; and   written step-by-step instructions for using the catheter to treat a target tissue within a patient by a method comprising the steps of:
 operatively coupling the catheter to the laser system; 
 guiding the catheter to the target tissue; 
 activating the laser system; and 
 advancing the catheter through the target tissue. 
   
     
     
         11 . The kit of  claim 10 , wherein the catheter further comprises a fiber configured to transmit the modified laser beam. 
     
     
         12 . The kit of  claim 11 , wherein the written step-by-step instructions for using the catheter to treat the target tissue within the patient by the method further comprises the step of flushing a fluid into a treatment site, wherein the treatment site comprises the target tissue. 
     
     
         13 . The kit of  claim 10 , wherein the step of guiding the catheter to the treatment site further comprises guiding the catheter over a guidewire. 
     
     
         14 . The kit of  claim 12 , wherein the fluid comprises saline or a substrate. 
     
     
         15 . A kit comprising:
 a catheter configured to operatively couple to a laser system, the laser system comprising: a laser source arranged to emit a pulsed laser beam comprising a beam propagation ratio (M2) greater than or equal to 10; and an optical system in optical communication with the laser source, the optical system comprising a plurality of optical elements arranged to receive the pulsed laser beam, and form, based in part on the pulsed laser beam, a modified pulsed laser beam comprising a pulse width less than or equal to 25 nanoseconds (ns), a temporal delay between at least two temporally separated component parts; wherein the temporal delay is equal to or less than a relaxation time of a target tissue; and   written directions for using the catheter to treat a target tissue within a patient by a method comprising the steps of:
 operatively coupling the catheter to the laser system; 
 guiding the catheter towards the target tissue; 
 activating the laser system; 
 advancing the catheter through the target tissue; and 
 deactivating the laser system. 
   
     
     
         16 . The kit of  claim 15 , wherein the written directions for using the catheter to treat the target tissue within the patient by the method further comprises the step of flushing a fluid into the patient. 
     
     
         17 . The kit of  claim 16 , wherein the fluid is saline, a dye, or a substrate. 
     
     
         18 . The kit of  claim 15 , wherein the catheter further comprises at least one optical fiber configured to transmit the modified laser beam. 
     
     
         19 . The kit of  claim 15 , wherein the step of advancing the catheter towards the target tissue further comprises exerting a distal force on the catheter. 
     
     
         20 . The kit of  claim 19 , wherein the distal force exerted on the catheter comprises an adjustable advancement rate.