Catheter for obstructed stent

A method of removing obstructive material from the interior of an axially extending stent implanted in a subject, comprising:

• engaging said subject with an elongate electrosurgical device including a tube having a proximal end and a distal end and an interior surface therebetween, said device having an ablation electrode proximate said distal end, said ablation electrode being positioned within said interior surface such that it is prevented from contacting the stent by said tube and is electrically unobstructed in a radial direction in relation to an axial direction defined by said stent while being shielded from physical contact with the stent;
• positioning said device so that the ablation electrode is at least partially with the stent;
• and
• supplying current from a current source to said ablation electrode to ablate said obstructive material.

A therapeutic method to increase flow through an at least partially obstructed lumen, comprising the steps of:

• deploying a stent with the abstract lumen;
• inserting an ablation device within the stent, the device having
• (a) an elongate flexible tube having a distal end and a proximal end and an interior surface therebetween, the tube defining an axial direction along a length of the tube and a radial direction radially away from the tube;
• (b) a first ablation electrode positioned within said interior surface proximate the distal end;
• (c) an ablation power supply in electrical communication with said ablation electrode;
• (d) wherein said first ablation electrode is shielded from physical contact with the stent by said tube when the first ablation electrode is positioned within the stent;
• and wherein said first ablation electrode is positioned so that it is electrically unobstructed in the radial direction by the tube while being shielded from physical contact with the stent, thereby being electrically operative in the radial direction with respect to its position along the axial direction;
• and
• using said ablation device to ablate obstructions from the stent.