Disclosed herein is an implantable blood pump assembly that includes a housing defining an inlet, an outlet, and a flow path extending from the inlet to the outlet, a rotor positioned within the flow path, a stator positioned within the housing and operable to drive the rotor, and an outflow cannula. The outflow cannula includes a coupler assembly configured for removable mechanical connection to the outlet coupler, and includes a first component of an anti-rotation mechanism and a first component of an axial lock. The housing includes an outlet coupler that includes a second component of the anti-rotation mechanism and a second component of the axial lock. The first and second components of the anti-rotation mechanism are positioned to engage one another prior to the first and second components of the axial lock during insertion of the outflow cannula into the housing outlet.