Apparatus and methods are described for manufacturing a housing for an impeller of a blood pump. A mandrel is placed inside an inner lining, with a central cylindrical portion of a frame disposed around the inner lining, the mandrel being shorter than a length of the inner lining. A portion of an elongate tube is placed around at least a portion of the frame. The inner lining, the frame and the portion of the elongate tube are heated, via the mandrel, and, while heating the inner lining, the frame, and the portion of the elongate tube, pressure is applied from outside the portion of the elongate tube, such as to cause the portion of the elongate tube to become coupled to the frame. Other applications are also described.

Apparatus and methods are described including a blood pump that includes an axial shaft configured for insertion into, and rotation within, a subject's body. The blood pump also includes an impeller, which includes a proximal bushing disposed over the axial shaft, a distal bushing disposed over the axial shaft distally from the proximal bushing, and one or more blades. Each of the blades includes a single inner helical elongate element, a single outer helical elongate element, and a film of material extending between the inner helical elongate element and the outer helical elongate element. The blades are proximally coupled to the proximal bushing and distally coupled to the distal bushing such that, as the axial shaft rotates, the blades rotate, thereby pumping blood of the subject. Other applications are also described.