Small vessel ultrasound cathter

Abstract

An ultrasound catheter adapted for accessing small vessels in the distal anatomy is disclosed. The ultrasound catheter comprises an elongate tubular body formed with a delivery lumen. The flexibility and dimensions of the tubular body allow access to the distal anatomy by advancement over the guidewire. An ultrasound radiating member is provided along the distal end portion of the tubular body for emitting ultrasound energy at a treatment site. A drug solution may also be delivered through the delivery lumen and out an exit port to the treatment site.

1 . A method of treating a small vessel, comprising:
 providing a first guidewire, an elongate outer sheath, and a second guidewire having an ultrasound radiating member disposed along a distal end;   advancing said first guidewire though a patient's vasculature to a treatment site;   advancing said elongate outer sheath over said first guidewire to said treatment site;   removing said first guidewire from said vasculature;   advancing said second guidewire through a delivery lumen of said elongate outer sheath such that said ultrasound radiating member is located along a distal end portion of said elongate outer sheath; and   emitting ultrasound energy from said ultrasound radiating member to said treatment site.   
     
     
         2 . The method of  claim 2 , further comprising delivering a drug solution through said delivery lumen to said treatment site. 
     
     
         3 . A method of treating an occlusion at a treatment site within a patient's vasculature comprising:
 providing a guidewire having a proximal region and a distal region opposite the proximal region, wherein an ultrasound radiating member is mounted in the guidewire distal region;   positioning the guidewire within the patient's vasculature, such that the ultrasound radiating member is adjacent to the treatment site;   advancing an elongate tubular body over a portion of the guidewire such that the ultrasound radiating member is not covered by the elongate tubular body, the elongate tubular body having an inner diameter greater than an outer diameter of the guidewire;   passing a therapeutic compound through an annulus formed between the elongate tubular body and the guidewire; and   emitting ultrasonic energy from the ultrasound radiating member.   
     
     
         4 . The method of  claim 3 , wherein the guidewire comprises a hollow, cylindrical hypotube. 
     
     
         5 . The method of  claim 3 , wherein a plurality of electrical conductors are passed through the guidewire. 
     
     
         6 . The method of  claim 3 , further comprising sensing a temperature at the treatment site. 
     
     
         7 . The method of  claim 3 , further comprising moving the guidewire simultaneously with the emission of ultrasonic energy from the ultrasound radiating member. 
     
     
         8 . The method of  claim 3 , further comprising imparting a shape to the elongate tubular body before advancing the elongate tubular body over the guidewire, the shape configured to facilitate the advancement of the elongate tubular body over the guidewire.