Method and device for thermal ablation having improved heat transfer

A thermal ablation system comprising:

• a catheter including an elongate member having proximal and distal ends an axial lumen, a resistive heating element mounted on an exterior surface over a predetermined length at the distal end of the elongate member, and a plurality of apertures extending radially outward from the axial lumen within the predetermined length of the exterior surface;
• a power supply connected to the resistive heating element;
• and
• means for inducing an oscillatory flow of thermally conductive medium past the resistive heating element in two directions.

A method for ablating a hollow body organ, said method comprising:

• percutaneously introducing a catheter into the interior of said hollow body organ, said catheter having a heating element and fluid distributing means at its distal end, wherein the heating element is directly exposed to fluid within the organ;
• introducing a thermally conductive medium into the hollow body organ through the fluid distributing means so that the medium is unconstrained and in direct thermal contact with the interior wall of the organ;
• heating the thermally conductive medium within the hollow body organ using the heating element;
• and
• alternately aspirating and expelling volumes of thermally conductive medium through the fluid distributing means past the heating element in a reversing flow pattern with substantially all the aspirated medium and all the expelled medium flowing past the heating element to effect mixing of the fluid and increase heat flux and uniformity of temperature distribution.

A thermal ablation catheter comprising:

• an elongate member having a proximal end, a distal end, and a lumen extending between said proximal and distal ends;
• a heating element disposed over a predetermined length of the distal end of the elongate member;
• means for suspending the heating element away from an exterior surface of the elongate member to form a circulation region between the surface and the heating element, wherein the means for suspending comprises three or more axial ribs formed along the distal end of the elongate member with trough regions between adjacent ribs defining the circulation region;
• and
• means for distributing a heat transfer fluid from the lumen to the region between the member surface and the heating element.

A thermal ablation system comprising:

• a catheter including an elongate member adapted for insertion into a hollow body cavity;
• said elongate member having proximal and distal ends and a resistive heating element having spaced-apart windings mounted on an exterior surface at the distal end of the elongate member;
• means for suspending the coil away from an exterior surface of the elongate member to form a circulation region between the surface and the coil;
• a power supply connected to the resistive heating element;
• and
• means for inducing an oscillatory flow of thermally conductive medium past the resistive heating element.

A method for ablating a hollow body organ, said method comprising:

• percutaneously introducing a catheter into the interior of said hollow body organ, said catheter having a heating element and fluid distributing means at its distal end, wherein the heater element is directly exposed to fluid within the organ;
• expanding a cage structure within the hollow body organ;
• positioning the heating element of the catheter within the expanded cage structure;
• introducing a thermally conductive medium into the hollow body organ through the fluid distributing means so that the medium is unconstrained and in direct thermal contact with the interior wall of the organ;
• heating the thermally conductive medium within the hollow body organ using the heating element;
• and
• alternately aspirating and expelling volumes of thermally conductive medium through the fluid distributing means to effect mixing of the fluid and increase heat flux and uniformity of temperature distribution.

A method for ablating a hollow body organ, said method comprising:

• percutaneously introducing a catheter into the interior of said hollow body organ, said catheter having a heating element and fluid distributing means at its distal end, wherein the heater element is directly exposed to fluid within the organ and the fluid distributing means directs fluid generally radially through the heating element;
• introducing a thermally conductive medium into the hollow body organ through the fluid distributing means so that the medium is unconstrained and in direct thermal contact with the interior wall of the organ;
• heating the thermally conductive medium within the hollow body organ using the heating element;
• and
• alternately aspirating and expelling volumes of thermally conductive medium through the fluid distributing means to effect mixing of the fluid and increase heat flux and uniformity of temperature distribution.

A method for ablating a hollow body organ, said method comprising:

• introducing a catheter into the interior of said hollow body organ;
• introducing a thermally conductive medium into the hollow body organ so that the medium is unconstrained and in direct thermal conduct with the interior wall of the organ;
• and
• alternately aspirating and expelling volumes of the thermally conductive medium through the catheter and past a heating element in a reversing flow pattern with substantially all the aspirated medium and all the expelled medium flowing past the heating element to effect mixing of the fluid and increase heat flux and uniformity of temperature distribution.