Fiber tip atherectomy catheter

A method of conducting an atherectomy procedure comprising the steps of:

• (a) advancing a balloon tipped tubular guide catheter containing a coaxially disposed and axially moveable drive tube with a cutter member attached to its distal end through the vascular system to the site of the atheroma to be treated, said cutter comprising a plurality of filaments adhered to said drive tube at only one end of said filaments;
• (b) inflating the balloon on said tubular guide catheter;
• (c) rotating said drive tube and cutter at a predetermined speed sufficient to cause said plurality of filaments to project radially from said drive tube while advancing said drive tube beyond the distal end of said guide catheter and into said atheroma;
• (d) during step (c), applying a vacuum to the proximal end of said drive tube for aspirating blood and tissue matter through the lumen of said drive tube;
• (e) deflating said balloon;
• and
• (f) repeating steps (a) through (e) until said balloon passes completely through the atheroma.

An atherectomy catheter assembly comprising:

• (a) a first, flexible tubular member of a predetermined outside and inside diameter having a proximal end, and distal end and a lumen extending from said proximal end to said distal end;
• (b) an inflatable expander member attached to said distal end of said first tubular member to be inflated by fluid passing through said lumen of said first tubular member;
• (c) a second tubular member having an outer diameter less than said predetermined inside diameter of said first tubular member, a proximal end, a distal end, and a lumen extending from said proximal end to said distal end of said second tubular member, said second tubular member being coaxially disposed within said lumen of said first tubular member with a predetermined clearance between said outer diameter of said second tubular member, allowing rotation and axial displacement of the distal end of said second tubular member beyond the distal end of said first tubular member;
• (d) a cutter member attached to said distal end of said second tubular member, said cutter member including a plurality of filamentary strands having one end thereof adhered to said distal end of said second tubular member and normally extending parallel to the axis of said second tubular member;
• (e) motor means coupled to said proximal end of said second tubular member for imparting rotation thereto within said lumen of said first tubular member;
• (f) means coupled to said proximal end of said first tubular member for directing fluid through said lumen of said first tubular member to inflate and deflate said expander member;
• (g) means for applying a negative pressure to said lumen of said second tubular member at the proximal end portion thereof;
• and
• (h) means located at said proximal end of said second tubular member for axially extending and retracting said distal end of said second tubular and said cutter member from said distal end of said first tubular member as said second member is being rotated by said motor means, rotation of said second tubular member causing said filamentary strands to project radially from said second tubular member.