A thrombus treatment device includes a support wire, a body frame portion that is disposed about an axis defined by the support wire, one or more tethers that each have a first end and a second end. Each of the one or more tethers is attached at its first end to the body frame portion, and at its second end to a collar that couples the second end of each of the multiple tethers to the support wire. When the collar is advanced to a position substantially within a region interior of the body frame portion, a rotational actuation of the support wire causes a swiveling motion of the one or more tethers. The swiveling motion of the tethers operates to macerate a thrombus.