Optical analyzer assembly with safety shutdown system for intravascular lithotripsy device

Abstract

A catheter system for treating a treatment site within or adjacent to a vessel wall or a heart valve, includes a light source, a balloon, a light guide and an optical analyzer assembly. The light source generates first light energy. The balloon is positionable substantially adjacent to the treatment site. The balloon has a balloon wall that defines a balloon interior that receives a balloon fluid. The light guide receives the first light energy and guides the first light energy in a first direction from a guide proximal end toward a guide distal end positioned within the balloon interior. The optical analyzer assembly optically analyzes a second light energy from the light guide that moves in a second direction that is opposite the first direction. The optical analyzer assembly includes a safety shutdown system to inhibit the first light energy from being received by the guide proximal end of the light guide.

1 . A method for treating a treatment site within or adjacent to a vessel wall or a heart valve with a catheter system, the method comprising the steps of:
 generating first light energy with a light source;   positioning a balloon substantially adjacent to the treatment site, the balloon having a balloon wall that defines a balloon interior, the balloon interior receiving a balloon fluid;   receiving the first light energy at a guide proximal end of a light guide;   guiding the first light energy in a first direction from the guide proximal end toward a guide distal end that is positioned within the balloon interior, the first light energy being configured to induce generation of a plasma within the balloon interior; and   optically analyzing, with an optical analyzer assembly, a second light energy from the light guide that moves in a second direction that is opposite the first direction, the optical analyzer assembly including a safety shutdown system that is selectively activated to inhibit the first light energy from the light source from being received by the guide proximal end of the light guide.   
     
     
         2 . The method of  claim 1  further comprising coupling a pulse generator to the light source; and triggering the light source to generate a source beam that is directed toward the light guide with the pulse generator; and wherein optically analyzing includes selectively activating a safety interlock of the safety shutdown system to block the pulse generator from triggering the generation of the source beam with the light source. 
     
     
         3 . The method of  claim 1  further comprising coupling a pulse generator to the light source; and triggering the light source to generate a source beam that is directed toward the light guide with the pulse generator; and wherein optically analyzing includes selectively activating a shutter of the safety shutdown system to block the source beam from being directed toward the light guide. 
     
     
         4 . The method of  claim 1  wherein optically analyzing includes optically determining with the optical analyzer assembly whether or not plasma generation has occurred within the balloon interior. 
     
     
         5 . The method of  claim 1  wherein optically analyzing includes optically detecting with the optical analyzer assembly a failure of the light guide between the guide proximal end and the guide distal end. 
     
     
         6 . The method of  claim 1  wherein optically analyzing includes optically analyzing the second light energy to detect at least two of (i) normal operation conditions; (ii) intermittent gas bubble production conditions; (iii) guide distal end plasma initiation conditions; (iv) plasma generation failure conditions; (v) broken light guide conditions; and (vi) chewback conditions. 
     
     
         7 . The method of  claim 1  wherein optically analyzing includes optically analyzing the second light energy to detect an operational condition of the catheter system; and the method further comprising directing a pulse of the first light energy through the light guide in the first direction to produce a plasma flash that can be captured by the optical analyzer assembly in the form of a flash signature that can include summary parameters including at least one of a pulse maximum value, rise time, width, start time relative to a reference, and a measure of signal volatility, which can provide an indication of the operational condition of the catheter system. 
     
     
         8 . The method of  claim 1  wherein generating first light energy includes the light source including a laser; and wherein receiving the first light energy includes the light guide including an optical fiber. 
     
     
         9 . A catheter system for treating a treatment site within or adjacent to a vessel wall or a heart valve, the catheter system comprising:
 a light source that generates first light energy;   a balloon that is positionable substantially adjacent to the treatment site, the balloon having a balloon wall that defines a balloon interior, the balloon interior receiving a balloon fluid;   a light guide that is configured to receive the first light energy at a guide proximal end and guide the first light energy in a first direction from the guide proximal end toward a guide distal end that is positioned within the balloon interior, the first light energy inducing generation of a plasma within the balloon interior; and   an optical analyzer assembly that is configured to optically analyze a second light energy from the light guide that moves in a second direction that is opposite the first direction, the optical analyzer being configured to optically analyze the second light energy to detect an operational condition of the catheter system, the optical analyzer assembly including a safety shutdown system that is selectively activated to inhibit the first light energy from the light source from being received by the guide proximal end of the light guide;   wherein a pulse of the first light energy being directed through the light guide in the first direction produces a plasma flash that can be captured by the optical analyzer assembly in the form of a flash signature that indicates an operational condition of the catheter system, the flash signature indicating at least one of a pulse maximum value, a rise time, a pulse width, a start time relative to a reference, and a measure of signal volatility.   
     
     
         10 . The catheter system of  claim 9  wherein, if the pulse maximum value of the flash signature is greater than a maximum pulse maximum threshold, then the optical analyzer assembly can identify the operational condition as a guide distal end plasma initiation condition. 
     
     
         11 . The catheter system of  claim 9  wherein, if the pulse maximum value of the flash signature is less than a minimum pulse maximum threshold, then the optical analyzer assembly can identify the operational condition as one of an intermittent gas bubble production condition, a plasma generation failure condition, and a broken light guide condition. 
     
     
         12 . The catheter system of  claim 11  wherein the optical analyzer assembly is configured to require that a number of pulses of first light energy where the pulse maximum value of the flash signature is less than a minimum pulse maximum threshold within a specified range of previous pulses exceeds a defined zero pulse count in order to identify the operational condition as one of an intermittent gas bubble production condition, a plasma generation failure condition, and a broken light guide condition. 
     
     
         13 . The catheter system of  claim 12  wherein a history of all pulses of first light energy directed through the light guide in the first direction is tracked to distinguish between the intermittent gas bubble production condition, the plasma generation failure condition, and the broken light guide condition. 
     
     
         14 . The catheter system of  claim 9  wherein the measure of signal volatility of the flash signature includes a number of transitions that are identified in the flash signature; and wherein, if the number of transitions in the flash signature is greater than a transition threshold, then the optical analyzer assembly can identify the operational condition as a chewback condition. 
     
     
         15 . A method for treating a treatment site within or adjacent to a vessel wall or a heart valve with a catheter system, the method comprising the steps of:
 generating first light energy with a light source;   positioning a balloon substantially adjacent to the treatment site, the balloon having a balloon wall that defines a balloon interior, the balloon interior receiving a balloon fluid;   receiving the first light energy at a guide proximal end of a light guide;   guiding the first light energy in a first direction from the guide proximal end toward a guide distal end that is positioned within the balloon interior;   optically analyzing, with an optical analyzer assembly, a second light energy from the light guide that moves in a second direction that is opposite the first direction, the optical analyzer being configured to optically analyze the second light energy to detect an operational condition of the catheter system, the optical analyzer assembly including a safety shutdown system that is selectively activated to inhibit the first light energy from the light source from being received by the guide proximal end of the light guide; and   directing a pulse of the first light energy through the light guide in the first direction to produce a plasma flash that can be captured by the optical analyzer assembly in the form of a flash signature that indicates an operational condition of the catheter system, the flash signature indicating at least one of a pulse maximum value, a rise time, a pulse width, a start time relative to a reference, and a measure of signal volatility.   
     
     
         16 . The method of  claim 15  wherein, if the pulse maximum value of the flash signature is greater than a maximum pulse maximum threshold, then the optical analyzer assembly can identify the operational condition as a guide distal end plasma initiation condition. 
     
     
         17 . The method of  claim 15  wherein, if the pulse maximum value of the flash signature is less than a minimum pulse maximum threshold, then the optical analyzer assembly can identify the operational condition as one of an intermittent gas bubble production condition, a plasma generation failure condition, and a broken light guide condition. 
     
     
         18 . The method of  claim 17  wherein the optical analyzer assembly is configured to require that a number of pulses of first light energy where the pulse maximum value of the flash signature is less than a minimum pulse maximum threshold within a specified range of previous pulses exceeds a defined zero pulse count in order to identify the operational condition as one of an intermittent gas bubble production condition, a plasma generation failure condition, and a broken light guide condition. 
     
     
         19 . The method of  claim 18  further comprising tracking a history of all pulses of first light energy directed through the light guide in the first direction to distinguish between the intermittent gas bubble production condition, the plasma generation failure condition, and the broken light guide condition. 
     
     
         20 . The method of  claim 15  wherein the measure of signal volatility of the flash signature includes a number of transitions that are identified in the flash signature; and wherein, if the number of transitions in the flash signature is greater than a transition threshold, then the optical analyzer assembly can identify the operational condition as a chewback condition.