Impeller for use in blood pump

A method, comprising:

• manufacturing an impeller by:
• cutting a tube such that the cut tube defines a structure having first and second end portions at proximal and distal ends of the structure, the end portions being connected to one another by at least one elongate element;
• tying sutures around the at least one elongate element;
• causing the at least one elongate element to radially expand and form at least one helical elongate element, by axially compressing the structure;
• and
• coupling a material to the at least one helical elongate element, such that the at least one helical elongate element with the material coupled thereto defines a blade of the impeller,
• the sutures being configured to facilitate coupling of the material to the helical elongate element,
• wherein the at least one helical elongate element has a first stiffness, wherein the material comprises a material having a lower stiffness than the first stiffness, and wherein tying sutures around the at least one elongate element comprises using the sutures as mediators, such as to enhance bonding between the at least one helical elongate element and the material.