Patent ID: 8556926

Claim:
A guidewire for insertion into a lumen, said guidewire comprising: a flexible wire having an outer diameter, an inner diameter, a proximal end and a distal end; a generally solid, rotatable core wire having an outer diameter, a proximal end and a distal end, with said distal end of said rotatable core wire slidably inserted into said proximal end of said flexible wire; a guide tip attached to said distal end of said rotatable core wire, wherein said guide tip comprises a boring surface; and a sheath, having an outer diameter and an inner diameter, a proximal end and a distal end, with said distal end of said sheath slidably insertable over said proximal end of said flexible wire, at least one centering device attached to said distal end of said flexible wire, said at least one centering device having a proximal end and a distal end, a smaller first diameter for insertion into said lumen, and a second larger diameter for centering said flexible wire in said lumen, said at least one centering device having said smaller first diameter when said sheath is slidably inserted over said flexible wire and said centering device, until said distal end of said sheath is substantially in contact with said guide tip, and said at least one centering device having said second larger diameter when said sheath is slidably retracted from said guide tip until said distal end of said sheath is no longer in contact with said at least one centering device.