Disclosed herein is an outflow graft assembly for an implantable blood pump. The outflow graft assembly includes a graft, a locking nut including a plurality of planar edges and a plurality of corners, and a U-shaped fixation clip. The U-shaped fixation clip includes a first flat segment including a first flexure including a first locking feature, a second flat segment including a second flexure including a second locking feature, an arcuate segment extending between the first flat segment and the second flat segment, and a lip including a first flat and a second flat. The U-shaped fixation clip is configured to engage the locking nut such that the first and second locking features contact associated corners of the plurality of corners and the first and second flats contact associated planar edges of the plurality of planar edges, thereby preventing rotation of the locking nut relative to the fixation clip.
