Atherectomy devices and methods

A method for performing rotational atherectomy to remove stenotic lesion material from an arteriovenous graft of a patient, the method comprising:

• delivering a portion of a rotational atherectomy system into the arteriovenous graft, wherein the rotational atherectomy system comprises:
• an rotational atherectomy device comprising:
• an elongate flexible drive shaft comprising a torque-transmitting coil and defining a longitudinal axis, the drive shaft being configured to rotate about the longitudinal axis;
• and
• a helical array of abrasive elements attached to a distal end portion of the drive shaft, each of the abrasive elements having a center of mass that is offset from the longitudinal axis, the centers of mass of each of the abrasive elements arranged along a spiral path around the longitudinal axis;
• and
• a controller;
• and
• rotating the drive shaft about the longitudinal axis such that the helical array of abrasive elements orbit around the longitudinal axis.