Impeller coupling portion

A method for manufacturing a blood pump, the method comprising:

• placing a first portion of a coupling element around an axial shaft configured for insertion into, and rotation within, a body of a subject,
• the first portion being made of a shape-memory material, being shaped to define one or more slits that facilitate a radial expansion of the first portion such that the first portion is placeable around the axial shaft, and being shape-set to have an inner diameter that is smaller than an outer diameter of the axial shaft such that, following the placement of the first portion around the axial shaft, the first portion becomes radially contracted around, and thus locked in place with respect to, the axial shaft;
• and
• coupling an impeller, which includes a bushing and one or more blades coupled to the bushing, to the axial shaft, by coupling the bushing to a second portion of the coupling element, such that, as the axial shaft rotates, the blades rotate, thereby pumping blood of the subject.