Rotational device with eccentric abrasive element and method of use

A rotational atherectomy device for removing an occlusion within a tubular structure, comprising:

• a drive shaft having a distal end section formed from at least one helically wound wire;
• a guidewire that is slidably receivable in a lumen of the flexible drive shaft;
• a rigid abrasive element on the distal end section having a center of mass offset from a longitudinal axis of the drive shaft in a first offset direction;
• and
• distal and proximal solid counterweights fixedly secured to the at least one helically wound wire on the distal end section and spaced apart from the abrasive element such that the entire distal solid counterweight is separated from the abrasive element by a first longitudinal portion of the drive shaft extending distally of a distal end of the abrasive element and the entire proximal solid counterweight is separated from the abrasive element by a second longitudinal portion of the drive shaft extending proximally of a proximal end of the abrasive element, each of the distal and proximal solid counterweights having a center of mass offset from the longitudinal axis of the drive shaft in a second offset direction that is opposite rom the first offset direction, each of the distal and proximal solid counterweights being smaller than the abrasive element, the abrasive element having an abrasive outer surface and the distal and proximal solid counterweights having non-abrasive outer surfaces,
• wherein the center of mass of each of the abrasive element and the counterweights is offset from the longitudinal axis such that the distal end section of the drive shaft bows in response to rotation of the drive shaft around the guidewire while the guidewire is fully withdrawn into the lumen of the drive shaft to a position that is proximal to the abrasive element.

A method of using a rotational atherectomy device to remove an occlusion from inside a tubular structure, comprising the steps of:

• inserting a drive shaft with an abrasive element thereon over a guidewire into a tubular structure, the abrasive element having a center of mass offset from a longitudinal axis of the drive shaft in a first offset direction, the abrasive element being spaced between distal and proximal solid counterweights on a distal end section of the drive shaft such that the entire distal solid counterweight is separated from the abrasive element by a first longitudinal portion of the drive shaft extending distally of a distal end of the abrasive element and the entire proximal solid counterweight is separated from the abrasive element by a second longitudinal portion of the drive shaft extending proximally of a proximal end of the abrasive element, each of the distal and proximal solid counterweights having a center of mass offset from the longitudinal axis of the drive shaft in a second offset direction that is opposite from the first direction;
• withdrawing a distal end of the guidewire into a lumen of the drive shaft such that the guidewire is positioned proximal to the abrasive element;
• and
• after withdrawal of the distal end of the guidewire into the lumen of the drive shaft, rotating the drive shaft over the guidewire so that the offset centers of mass of the abrasive element and the counterweights cause the drive shaft to bow as the abrasive element moves in an orbital path.