Flexible microwave catheters for natural or artificial lumens

Abstract

A method for forming a resonating structure within a body lumen, the method including advancing a flexible microwave catheter into a body lumen of a patient, the flexible microwave catheter including a radiating portion at the distal end of the flexible microwave catheter, the radiating portion configured to receive microwave energy, and at least one centering device proximate the radiating portion configured to deploy radially outward from the flexible microwave catheter; positioning the radiating portion near tissue of interest; deploying the at least one centering device radially outward from the flexible microwave catheter within the body lumen such that a longitudinal axis of the radiating portion is substantially parallel with and at a fixed distance from a longitudinal axis of the body lumen near the targeted tissue; and delivering microwave energy to the radiating portion such that a circumferentially balanced resonating structure is formed with the body lumen.

What is claimed is: 
     
         1 . A method for forming a resonating structure within a body lumen, the method comprising:
 advancing a flexible microwave catheter into a body lumen of a patient, the flexible microwave catheter including:
 a radiating portion at the distal end of the flexible microwave catheter, the radiating portion configured to receive microwave energy, and 
 at least one centering device proximate the radiating portion configured to deploy radially outward from the flexible microwave catheter; 
   positioning the radiating portion near targeted tissue;   deploying the at least one centering device radially outward from the flexible microwave catheter within the body lumen such that a longitudinal axis of the radiating portion is substantially parallel with and at a fixed distance from a longitudinal axis of the body lumen near the targeted tissue; and   delivering microwave energy to the radiating portion such that a circumferentially balanced resonating structure is formed with the body lumen.   
     
     
         2 . The method according to  claim 1 , wherein the circumferentially balanced resonating structure radiates energy 360 degrees around the longitudinal axis of the radiating portion and along a longitudinal span of about 2 to about 3 cm. 
     
     
         3 . The method of  claim 1 , wherein the body lumen is the renal artery. 
     
     
         4 . The method of  claim 3 , wherein the targeted tissue is one or more renal nerves and the circumferentially balanced resonating structure generates an electromagnetic field that denervates the targeted tissue. 
     
     
         5 . The method of  claim 1 , further including the steps of:
 providing a continuous fluid flow within the body lumen; and   cooling at least a portion of the body lumen.   
     
     
         6 . The method of  claim 5 , further including the steps of:
 monitoring the temperature of the continuous fluid flow; and   terminating the delivery of microwave energy if the monitored temperature exceeds a threshold temperature.   
     
     
         7 . The method of  claim 1 , further including the step of:
 continuing delivery of the microwave energy until a sufficient amount of energy is delivered to effectively damage the targeted tissue while preserving the critical structure of the body lumen.   
     
     
         8 . The method of  claim 1 , wherein the body lumen is selected from at least one of a gastrointestinal lumen, an auditory lumen, a respiratory system lumen, urinary system lumen, a female reproductive system lumen, a male reproductive system lumen, a vascular system lumen, and an internal organ. 
     
     
         9 . The method of  claim 1 , further including the step of expanding the body lumen to form a structure related to the microwave frequency. 
     
     
         10 . The method of  claim 1 , further including the step of delivering microwave energy at a frequency that is selected to be resonate with the body lumen. 
     
     
         11 . The method of  claim 1 , further including the steps of:
 monitoring a temperature within the body lumen; and   terminating the delivery of the microwave energy signal when the temperature exceeds a threshold temperature.   
     
     
         12 . The method of  claim 1 , wherein the radiating portion includes a feed gap forming an open circuit in the flexible microwave catheter. 
     
     
         13 . The method of  claim 1 , wherein the radiating portion includes a first feed gap and a second feed gap, and wherein the first and second feed gaps each form open circuits in the flexible microwave catheter. 
     
     
         14 . A method for forming a resonating structure within a body lumen, the method comprising:
 advancing a flexible microwave catheter into a body lumen of a patient, the flexible microwave catheter including:
 a radiating portion at the distal end of the flexible microwave catheter, the radiating portion configured to receive a microwave energy signal at a microwave frequency; and 
 an electrically conductive mesh adjacent the radiating portion; and 
 a retractable sheath configured to deploy the electrically conductive mesh about the radiating portion; 
   positioning the radiating portion adjacent a targeted tissue;   retracting the retractable sheath;   deploying the electrically conductive mesh radially outward from the flexible microwave catheter and within the body lumen thereby centering the radiating portion at the radial center of the body lumen;   forming a circumferentially balanced resonating structure within the body lumen via the radiating portion, and   delivering the microwave energy signal at the microwave frequency to resonate the body lumen at the microwave frequency.   
     
     
         15 . The method of  claim 14 , further including the step of:
 forming a window in the electrically conductive mesh, the window being characterized by a lack of material; and   heating a region of the body lumen related to the window.   
     
     
         16 . The method of  claim 15 , wherein the body lumen is a renal artery, the targeted tissue is a renal nerve, and heating the region of the body lumen related to the window at least partially denervates the kidney. 
     
     
         17 . The method of  claim 16 , further including the step of cooling at least a portion of the renal artery. 
     
     
         18 . The method of  claim 15 , further including the step of:
 providing a fluid cooling structure to enhance energy delivery and reduce heating of a least a portion of the flexible microwave catheter.   
     
     
         19 . The method of  claim 15 , wherein the body lumen is selected from at least one of a gastrointestinal lumen, an auditory lumen, a respiratory system lumen, urinary system lumen, a female reproductive system lumen, a male reproductive system lumen, a vascular system lumen, and an internal organ. 
     
     
         20 . The method according to  claim 15 , wherein the circumferentially balanced resonating structure radiate energy over 360 degrees along a longitudinal span of about 2 to 3 cm.