Ultrasound Therapy System

Abstract

In one embodiment of the present invention, a system for treating an occlusion within a patient's vasculature with ultrasonic energy comprises a catheter configured to be passed through the patient's vasculature such that a portion of the catheter is positioned at an intravascular treatment site. The system further comprises an ultrasound radiating member, an ultrasound signal generator configured to supply a drive signal to the ultrasound radiating member, an infusion pump configured to pump a therapeutic compound into the fluid delivery lumen so as to cause the therapeutic compound to be delivered to the treatment site and a controller configured to control the ultrasound signal generator and the infusion pump.

1 . A system for treating an occlusion within a patient's vasculature with ultrasonic energy, the system comprising: 
 a catheter configured to be passed through the patient's vasculature such that a portion of the catheter is positioned at an intravascular treatment site, wherein the catheter includes a fluid delivery lumen having a distal fluid delivery port;    an ultrasound radiating member positioned within the catheter;    an ultrasound signal generator configured to supply a drive signal to the ultrasound radiating member so as to cause ultrasonic energy to be delivered to the treatment site;    an infusion pump configured to pump a therapeutic compound into the fluid delivery lumen so as to cause the therapeutic compound to be delivered through the distal fluid delivery port to the treatment site; and    a controller configured to control the ultrasound signal generator and the infusion pump such that (a) when the ultrasound signal generator is supplying the drive signal to the ultrasound radiating member the infusion pump is in an idle state, and (b) when the infusion pump is pumping a therapeutic compound into the fluid delivery lumen the ultrasound signal generator is in an idle state.    
   
   
       2 . The system of  claim 1 , wherein the infusion pump is selected from the group consisting of a rotating syringe pump and a peristaltic pump.  
   
   
       3 . The system of  claim 1 , wherein the therapeutic compound is a microbubble therapeutic compound.  
   
   
       4 . The system of  claim 3 , wherein the microbubble therapeutic compound has a microbubble concentration between approximately 4×10 6  and approximately 12×10 9  microbubbles per milliliter.  
   
   
       5 . The system of  claim 3 , wherein the microbubble therapeutic compound has an average microbubble diameter that is between approximately 0.4 μm and approximately 6 μm.  
   
   
       6 . The system of  claim 3 , wherein the microbubble therapeutic compound comprises octafluoropropane encapsulated in a plurality of lipid shells.  
   
   
       7 . The system of  claim 1 , wherein the infusion pump is configured to pump the therapeutic compound into the delivery lumen at an infusion rate that is between approximately 10 mL per hour and approximately 120 mL per hour.  
   
   
       8 . The system of  claim 1 , further comprising a first reservoir configured to hold the therapeutic compound, wherein: 
 the therapeutic compound is a microbubble therapeutic compound; and    the infusion pump is configured to pump the therapeutic compound from the first reservoir into the fluid delivery lumen.    
   
   
       9 . The system of  claim 8 , further comprising a second reservoir configured to hold a supplemental therapeutic compound, wherein the infusion pump is further configured to pump the supplemental therapeutic compound from the second reservoir into the fluid delivery lumen.  
   
   
       10 . The system of  claim 9 , wherein the supplemental therapeutic compound does not include microbubbles.  
   
   
       11 . The system of  claim 10 , wherein the controller is further configured to control the infusion pump such that when the ultrasound signal generator is supplying the drive signal to the ultrasound radiating member the infusion pump is not pumping the therapeutic compound into the fluid delivery lumen, and is pumping the supplemental therapeutic compound into the fluid delivery lumen.  
   
   
       12 . The system of  claim 8 , further comprising an agitator configured to supply mechanical vibrations to the first reservoir.  
   
   
       13 . The system of  claim 12 , wherein the controller is configured to control the agitator.  
   
   
       14 . The system of  claim 1 , wherein the distal fluid delivery port is positioned adjacent to the ultrasound radiating member, such that a therapeutic compound delivered from the distal fluid delivery port is within an ultrasonic energy field generated by the ultrasound radiating member.  
   
   
       15 . A system comprising: 
 a catheter having a proximal region and a distal region, the catheter including (a) a fluid delivery lumen extending from an infusion port in the proximal region to a delivery port in the distal region, (b) an ultrasound radiating member positioned in the distal region, and (c) an elongate conductor extending from the ultrasound radiating member to the proximal region;    an ultrasound signal generator configured to supply a drive signal to the ultrasound radiating member via the elongate conductor;    a microbubble therapeutic compound reservoir coupled to the infusion port via an infusion pump, the infusion pump being configured to pump fluid from the microbubble therapeutic compound reservoir into the infusion port; and    a controller configured to control the ultrasound signal generator and the infusion pump such that (a) when the infusion pump is pumping fluid into the infusion port the ultrasound signal generator is not supplying a drive signal to the ultrasound radiating member, and (b) when the infusion pump is not pumping fluid into the infusion port the ultrasound signal generator is supplying a drive signal to the ultrasound radiating member.    
   
   
       16 . The system of  claim 15 , wherein the catheter includes a plurality of ultrasound radiating members positioned in the distal region.  
   
   
       17 . The system of  claim 15 , wherein the ultrasound radiating member is movable relative to the delivery port.  
   
   
       18 . The system of  claim 15 , wherein the ultrasound radiating member is a hollow cylinder, and wherein the fluid delivery lumen passes through the ultrasound radiating member.  
   
   
       19 . The system of  claim 15 , further comprising an agitator configured to impart mechanical motion to the microbubble therapeutic compound reservoir.  
   
   
       20 . The system of  claim 19 , wherein the controller is further configured to control the agitator.  
   
   
       21 . The system of  claim 15 , further comprising a therapeutic compound reservoir coupled to the infusion port via the infusion pump.  
   
   
       22 . The system of  claim 21 , wherein the controller is configured to control the infusion pump such that the infusion pump does not pump fluid into the infusion port from the microbubble therapeutic compound reservoir and the therapeutic compound reservoir simultaneously.  
   
   
       23 . The system of  claim 22 , wherein the controller is further configured to pump fluid into the infusion port from the therapeutic compound reservoir when the ultrasound signal generator is supplying a drive signal to the ultrasound radiating member.  
   
   
       24 . A method of treating a vascular occlusion, the method comprising: 
 providing an ultrasound catheter having a treatment zone, an ultrasound radiating member positioned within the treatment zone, and a fluid delivery lumen hydraulically coupled to an exit port within the treatment zone;    positioning the ultrasound catheter within a patient;    delivering, through the fluid delivery lumen and the exit port, a microbubble therapeutic compound to the internal portion of the vascular occlusion; and    delivering ultrasonic energy to the vascular occlusion, wherein the ultrasonic energy causes cavitation to occur within the microbubble therapeutic compound delivered to the vascular occlusion.    
   
   
       25 . The method of  claim 24 , further comprising positioning the ultrasound catheter within a patient's vasculature such that at least a portion of the treatment zone is located in an internal portion of the vascular occlusion.  
   
   
       26 . The method of  claim 25 , wherein an exterior surface of the treatment zone includes a cavitation promoting surface.  
   
   
       27 . The method of  claim 26 , wherein the cavitation promoting surface is patterned with features from an ablative laser.  
   
   
       28 . The method of  claim 25 , wherein delivering ultrasonic energy to the vascular occlusion causes stable cavitation to occur without causing substantial inertial cavitation.  
   
   
       29 . The method of  claim 25 , wherein the microbubble therapeutic compound comprises microbubbles infused with a drug.  
   
   
       30 . The method of  claim 24 , further comprising positioning the ultrasound catheter outside a patient's vasculature such that at least a portion of the treatment zone is located outside the patient's vasculature.  
   
   
       31 . A method of manufacturing an ultrasound catheter, the method comprising: 
 providing an elongate catheter body having a distal region, a proximal region opposite the distal region, and an exterior surface;    positioning an ultrasound radiating member within the distal region of the elongate catheter body;    forming a fluid delivery lumen within the elongate catheter body, wherein the fluid delivery lumen extends between the proximal region and the distal region;    providing a fluid delivery port in the distal region of the elongate catheter body, the fluid delivery port being hydraulically connected to the fluid delivery lumen; and    forming a plurality of surface features on the exterior surface of the catheter body distal region using an ablative laser.    
   
   
       32 . The method of  claim 31 , wherein the plurality of surface features comprise a plurality of holes that do not extend through the catheter body.  
   
   
       33 . The method of  claim 31 , wherein the ablative laser is an excimer laser.  
   
   
       34 . The method of  claim 31 , wherein the plurality of surface features are formed using a mask projection technique.  
   
   
       35 . The method of  claim 31 , wherein: 
 the plurality of surface features comprise a plurality of holes that do not extend through the catheter body; and    wherein the plurality of holes have a diameter between approximately 1 μm and approximately 100 μm.    
   
   
       36 . The method of  claim 31 , wherein: 
 the plurality of surface features comprise a plurality of holes that do not extend through the catheter body; and    wherein the plurality of holes are separated from each other by an average distance that is between approximately 1 μm and approximately 100 μm.    
   
   
       37 . The method of  claim 31 , wherein the plurality of surface features are formed adjacent to the ultrasound radiating member.  
   
   
       38 . The method of  claim 31 , wherein the plurality of surface features of formed adjacent to the fluid delivery port.  
   
   
       39 . An apparatus comprising: 
 an elongate, hollow catheter body having a distal region, a proximal region opposite the distal region, and an exterior surface;    an ultrasound radiating member positioned with the distal region of the catheter body;    a fluid delivery lumen extending between the proximal region and the distal region of the catheter body; and    a plurality of holes formed in the exterior surface of the catheter body distal region.    
   
   
       40 . The apparatus of  claim 39 , further comprising a fluid delivery port formed in the distal region of the elongate catheter body, the fluid delivery port being hydraulically connected to the fluid delivery lumen.  
   
   
       41 . The apparatus of  claim 39 , wherein the plurality of holes do not extend through the catheter body.  
   
   
       42 . The apparatus of  claim 39 , wherein the plurality of holes are formed using an ablative laser.  
   
   
       43 . The apparatus of  claim 39 , wherein the plurality of holes have a diameter between approximately 1 μm and approximately 100 μm.  
   
   
       44 . The apparatus of  claim 39 , wherein the plurality of holes are separated from each other by an average distance that is between approximately 1 μm and approximately 100 μm.  
   
   
       45 . The apparatus of  claim 39 , wherein the plurality of holes are positioned adjacent to the ultrasound radiating member.  
   
   
       46 . The apparatus of  claim 39 , further comprising a plurality of ultrasound radiating members positioned within the distal region of the catheter body.