Methods and Apparatus for Utilizing Impeller-Based Rotationally-Scanning Catheters

Abstract

An ablation catheter includes a tubular catheter body having a lumen, a tip portion, a liquid inlet, at least one liquid outlet, a liquid flow path defined between the liquid inlet and the liquid outlet, and an ablation element mounted on the tip portion of the catheter body. A rotationally-scanning ultrasound assembly is disposed within the lumen of the catheter body adjacent the tip portion. The ultrasound assembly includes an ultrasound transducer having an active face, an acoustic mirror acoustically coupled to the active face of the ultrasound transducer, and an impeller positioned in the liquid flow path and operably coupled to at least one of the ultrasound transducer and the acoustic mirror to impart rotational motion thereto when a liquid flows through the impeller.

1 - 31 . (canceled) 
     
     
         32 . A method of manufacturing an ablation catheter, comprising:
 providing a tubular catheter body having a tip portion, a lumen, and at least one liquid outlet extending from the lumen through a wall of the catheter body;   mounting an ablation element on the tip portion;   placing a rotationally-scanning ultrasound assembly within the lumen adjacent the tip portion, the ultrasound assembly including a transducer; and   operably coupling an impeller to the ultrasound assembly to impart rotational motion to the ultrasound assembly when a liquid flows through the impeller and is exhausted through the at least one liquid outlet.   
     
     
         33 . The method according to  claim 32 , further comprising micromolding the impeller. 
     
     
         34 . The method according to  claim 32 , wherein the step of operably coupling the impeller to the ultrasound assembly comprises operably coupling the impeller to the transducer. 
     
     
         35 . The method according to  claim 32 , wherein the ultrasound assembly further comprises an acoustic mirror acoustically coupled to the transducer, and the step of operably coupling the impeller to the ultrasound assembly comprises operably coupling the impeller to the acoustic mirror. 
     
     
         36 . The method according to  claim 35 , wherein the step of operably coupling the impeller to the acoustic mirror comprises micromolding a unitary assembly including the impeller and the acoustic mirror. 
     
     
         37 . The method according to  claim 35 , wherein the acoustic mirror is positioned proximally of the transducer. 
     
     
         38 . The method according to  claim 35 , wherein the acoustic mirror is positioned distally of the transducer. 
     
     
         39 . The method according to  claim 32 , wherein the impeller includes a central passageway, further comprising the steps of:
 providing at least one lead;   attaching an end of the at least one lead to at least one of the ablation element and the transducer; and   routing the lead proximally through the central passageway of the impeller.   
     
     
         40 . The method according to  claim 32 , wherein the ultrasound assembly further comprises an acoustic lens acoustically coupled to an active face of the transducer via an acoustic coupling medium. 
     
     
         41 . The method according to  claim 32 , wherein the ablation element comprises a radiofrequency ablation element. 
     
     
         42 . The method according to  claim 32 , wherein placing a rotationally-scanning ultrasound assembly within the lumen adjacent the tip portion comprises slidably mounting the rotationally-scanning ultrasound assembly within the lumen adjacent the tip portion. 
     
     
         43 . An ablation catheter, comprising:
 a tubular catheter body configured for insertion into a body, the tubular catheter body including at least one liquid outlet extending through a wall of the catheter and in fluid communication with a lumen defined by the catheter body;   an ablation element mounted to a distal end of the tubular catheter body; and   a rotationally-scanning ultrasound assembly positioned within the lumen and oriented such that a visualization field of the rotationally-scanning ultrasound assembly includes a tissue being ablated by the ablation element, the rotationally-scanning ultrasound assembly comprising:
 an ultrasound transducer; and 
 an impeller, 
   wherein a liquid flowing throw the impeller imparts rotational motion to the rotationally-scanning ultrasound assembly before being exhausted in vivo through the at least one liquid outlet.   
     
     
         44 . The ablation catheter according to  claim 43 , wherein the impeller is coupled to the ultrasound transducer such that rotation of the impeller imparts rotational motion to the ultrasound transducer. 
     
     
         45 . The ablation catheter according to  claim 43 , wherein the rotationally-scanning ultrasound assembly further comprises an acoustic mirror, and wherein the impeller is coupled to the acoustic mirror such that rotation of the impeller imparts rotational motion to the acoustic mirror. 
     
     
         46 . The ablation catheter according to  claim 45 , wherein at least one of the acoustic mirror and the ultrasound transducer is oriented non-orthogonally to a central axis of the catheter body, such that the visualization field of the rotationally-scanning ultrasound assembly includes the tissue being ablated by the ablation element. 
     
     
         47 . The ablation catheter according to  claim 43 , wherein the rotationally-scanning ultrasound assembly is slidably mounted within the lumen. 
     
     
         48 . The ablation catheter according to  claim 43 , wherein the ablation element comprises a radiofrequency ablation element.