Ablation system with catheter clearing abrasive

A method for ablating a lesion in a patient's vessel using an ablation burr system comprising:

• routing an atherectomy burr that is connected to a driveshaft over a guidewire to a position just proximate to said lesion, said burr having a proximal surface;
• routing an aspiration catheter over the driveshaft to a position just proximate to said burr, said aspiration catheter having proximal and distal ends and including a lumen extending longitudinally therethrough, said lumen forming an aspiration mouth at said distal end of said aspiration catheter, wherein said aspiration catheter includes a filter section defining a portion of said lumen that cooperates with said proximal surface of said burr;
• rotating and advancing said burr distally through said lesion causing loose lesion particulate to separate from the vessel wall;
• aspirating said loose lesion particulate with said aspiration catheter;
• filtering at least some of said loose lesion particulate by trapping said loose lesion particulate in said filter section;
• and
• clearing said filter section from said trapped lesion particulate by moving said rotating burr toward said aspiration catheter and into engagement with said trapped lesion particulate so that said proximal surface of the burr breaks down said trapped lesion particulate for removal by said catheter.