Systems and methods for treating a hollow anatomical structure

Abstract

A catheter includes multiple primary leads to deliver energy for ligating a hollow anatomical structure. Each of the primary leads includes a resistive element located at the working end of the catheter. Separation is maintained between the leads such that each lead can individually receive power. The catheter can include a lumen to accommodate a guide wire or to allow fluid delivery. Energy is applied until the diameter of the hollow anatomical structure is reduced to the point where occlusion is achieved. In one embodiment, a balloon is inflated to place the resistive elements into apposition with a hollow anatomical structure and to occlude the structure before the application of energy. The inflated balloon impairs blood flow and facilitates the infusion of saline, or medication, to the hollow anatomical structure in order to reduce the occurrence of coagulation and to improve the heating of the structure by the catheter.

What is claimed is: 
     
         1 . An apparatus for treatment of a hollow anatomical structure (HAS), the apparatus comprising:
 a catheter sized for insertion into the HAS, the catheter including an elongate shaft having a proximal end, a working end, and at least one lumen extending through at least a portion of the shaft;   wherein the catheter working end comprises
 an elongate flexible wire extending distally from the catheter shaft and having a plurality of spaced, expandable, formed bends when in an unstressed state; 
 an electrically resistive coil helically wound around at least a portion of the wire; and 
 an insulative outer sleeve encasing the resistive coil so as to prevent electrical contact and electrical conduction with tissue. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the catheter working end further comprises a temperature sensor. 
     
     
         3 . The apparatus of  claim 1 , wherein the outer sleeve is a low friction material. 
     
     
         4 . The apparatus of  claim 1 , wherein a direction of each bend alternates along a length of the wire so that the wire resembles a sine wave when viewed in profile. 
     
     
         5 . The apparatus of  claim 4 , wherein a height of the wire, measured as a peak-to-peak distance between adjacent bends, is greater than an outside diameter of the catheter shaft. 
     
     
         6 . The apparatus of  claim 5 , wherein the wire may be withdrawn proximally with respect to the catheter shaft into the at least one lumen. 
     
     
         7 . The apparatus of  claim 6 , wherein when the wire is withdrawn into the at least one lumen the wire becomes straighter. 
     
     
         8 . The apparatus of  claim 1 , wherein the wire comprises a shape memory material. 
     
     
         9 . The apparatus of  claim 1 , wherein the at least one lumen includes an inner liner. 
     
     
         10 . The apparatus of  claim 9 , wherein the inner liner extends out a distal end of the at least one lumen and wraps around the distal end to form an outer lip. 
     
     
         11 . A method for treating a hollow anatomical structure (HAS), the method comprising:
 inserting a catheter into the HAS, the catheter including an elongate shaft having a proximal end, a working end, and at least one lumen extending through at least a portion of the shaft;   wherein the catheter working end comprises
 an elongate flexible wire extending distally from the catheter shaft and having a plurality of spaced, expandable, formed bends when in an unstressed state; and 
 an electrically resistive coil helically wound around at least a portion of the wire; 
   advancing the catheter through the HAS until the wire is located at a treatment site; and   applying energy to the resistive coil to heat the coil, thereby heating and constricting a lumen of the HAS at the treatment site.   
     
     
         12 . The method of  claim 11 , wherein applying energy to the resistive coil comprises selecting a constant power output of an energy source. 
     
     
         13 . The method of  claim 11 , further comprising sensing a temperature at the treatment site. 
     
     
         14 . The method of  claim 13 , further comprising adjusting the energy applied to the resistive coil in response to the sensed temperature. 
     
     
         15 . The method of  claim 14 , further comprising delivering fluid to the HAS before application of the energy to the resistive coil. 
     
     
         16 . The method of  claim 15 , wherein the fluid comprises saline or a venoconstrictor. 
     
     
         17 . The method of  claim 11 , further comprising ceasing application of the energy to the resistive coil, drawing the catheter proximally through the HAS to a second treatment site, and applying energy to the resistive coil to heat the coil, thereby heating and constricting the lumen of the HAS at the second treatment site. 
     
     
         18 . The method of  claim 11 , wherein a direction of each bend alternates along a length of the wire so that the wire resembles a sine wave when viewed in profile. 
     
     
         19 . The method of  claim 18 , wherein a height of the wire, measured as a peak-to-peak distance between adjacent bends, is greater than an outside diameter of the catheter shaft. 
     
     
         20 . The method of  claim 11 , wherein the wire comprises a shape memory material.