Use of focused ultrasound for vascular sealing

Abstract

An ultrasonic applicator unit ( 2 ) is used diagnostically to locate a puncture wound ( 316 ) in an artery and then therapeutically to seal the puncture wound with high intensity focused ultrasound (HIFU). A control unit ( 6 ) coupled to the applicator unit includes a processor ( 74 ) that automates the procedure, controlling various parameters of the diagnostic and therapeutic modes, including the intensity and duration of the ultrasonic energy emitted by the applicator unit. A protective, sterile acoustic shell ( 4 ), which is intended to be used with a single patient and then discarded, is slipped over the applicator unit to protect against direct contact between the applicator unit and the patient and to maintain a sterile field at the site of the puncture. The apparatus and method are particularly applicable to sealing a puncture made when inserting a catheter into an artery or other vessel. Several different procedures are described for locating the puncture wound, including imaging the vessel in which the puncture is disposed and use of a locator rod to determine the disposition of the puncture along the longitudinal axis of the artery.

1 . A method of positioning a therapeutic applicator relative to the location of a puncture site in a vessel, the method comprising: 
 inserting an elongated puncture site locator through the puncture site and into the vessel; and    positioning the therapeutic applicator relative to the locator.    
     
     
         2 . The method of  claim 1 , wherein the locator comprises a spatial position resolving element.  
     
     
         3 . The method of  claim 2 , wherein the spatial resolving element comprises a magnetic position sensor.  
     
     
         4 . The method of  claim 2 , wherein the spatial resolving element comprises an optical position sensor.  
     
     
         5 . The method of  claim 2 , wherein the spatial resolving element comprises an acoustic position sensor.  
     
     
         6 . The method of  claim 2 , comprising positioning the therapeutic applicator relative to the spatial resolving element.  
     
     
         7 . The method of  claim 1 , wherein positioning the therapeutic applicator relative to the locator comprises using an ultrasonic pulse-echo technique.  
     
     
         8 . The method of  claim 1 , wherein positioning the therapeutic applicator relative to the locator comprises making an ultrasonic time-of-flight measurement.  
     
     
         9 . The method of  claim 1 , wherein the locator extends through the puncture site from outside a patient.  
     
     
         10 . The method of  claim 1 , wherein the locator comprises a substantially rigid rod.  
     
     
         11 . The method of  claim 1 , wherein the locator comprises a guide wire.  
     
     
         12 . The method of  claim 1 , wherein the locator comprises an introducer.  
     
     
         13 . An apparatus for positioning a therapeutic applicator relative to the location of a puncture site in a vessel, the apparatus comprising: 
 an elongated puncture site locator dimensioned such that it can be inserted through the puncture site and into the vessel from the outside a patient; and    a spatial position resolving element positioned on the locator.    
     
     
         14 . The method of  claim 13 , wherein the locator comprises a substantially rigid rod.  
     
     
         15 . The method of  claim 13 , wherein the locator comprises a guide wire.  
     
     
         16 . The method of  claim 13 , wherein the locator comprises an introducer.  
     
     
         17 . The method of  claim 13 , wherein the spatial resolving element comprises a magnetic position sensor.  
     
     
         18 . The method of  claim 13 , wherein the spatial resolving element comprises an optical position sensor.  
     
     
         19 . The method of  claim 13 , wherein the spatial resolving element comprises an acoustic position sensor.  
     
     
         20 . A method for sealing a vascular opening in a patient's body, comprising: 
 identifying a treatment zone to which ultrasonic energy should be applied to close the vascular opening;    applying compressive force to the treatment zone; and    directing ultrasonic energy towards the treatment zone.    
     
     
         21 . The method of  claim 20 , wherein the ultrasound energy directed towards the treatment zone is high intensity focused ultrasound (HIFU) energy.  
     
     
         22 . The method of  claim 20 , wherein the treatment zone is located on a femoral, brachial, or radial artery.  
     
     
         23 . The method of  claim 20 , comprising over-scanning the treatment zone with the ultrasonic energy, thereby ensuring that the vascular opening is treated and sealed.  
     
     
         24 . A system for sealing a vascular opening in a patient's body, comprising: 
 an applicator unit comprising 
 an outer housing configured to be hand held and  
 a high intensity focused ultrasound (HIFU) transducer array assembly having a substantially flat face and coupled to the outer housing, wherein the transducer array assembly is configured to apply a substantially compressive, controllable force on tissues in the patient's body when the substantially flat face contacts the tissues and force is applied to the outer housing; and  
   a control unit configured to excite the transducer array such that the array produces high intensity focused ultrasound (HIFU).    
     
     
         25 . The system of  claim 24 , wherein the outer housing is constructed from an injection moldable plastic.  
     
     
         26 . The system of  claim 24 , wherein the transducer array is a phased array.  
     
     
         27 . The system of  claim 24 , wherein the transducer array is an annular array.  
     
     
         28 . The system of  claim 24 , wherein the control unit comprises a radio frequency generator.  
     
     
         29 . The system of  claim 24 , wherein the applicator unit weighs about 1 pound or more.