Impeller for use in blood pump
Apparatus and methods are described including an impeller that includes an impeller frame that comprises proximal and distal end portions and at least one helical elongate element that winds from the proximal end portion to the distal end portion. A material is coupled 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. A plurality of sutures are tied around the at least one helical elongate element, the sutures being configured to facilitate coupling of the material to the at least one helical elongate element. Other applications are also described.
1. 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.
2. The method according to claim 1 , wherein coupling a material to the at least one helical elongate element comprises coupling the material to the at least one helical elongate element such that the material defines a hollow central lumen therethrough, the hollow central lumen facilitating the insertion of an axial support member through the hollow central lumen.
3. The method according to claim 1 , wherein manufacturing the impeller comprises manufacturing a biocompatible impeller that is configured to be inserted into a blood vessel of a subject.
4. The method according to claim 1 , wherein cutting the tube further comprises forming a notch in an edge of at least one of the end portions, the notch being configured to facilitate coupling of the material to the at least one helical elongate element.
5. The method according to claim 1 , wherein cutting the tube comprises cutting the 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 three elongate elements, and wherein causing the at least one elongate element to radially expand and form at least one helical elongate element comprises causing the three elongate elements to form three helical elongate elements.
6. The method according to claim 1 , wherein cutting the tube comprises cutting the 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 two elongate elements, and wherein causing the at least one elongate element to radially expand and form at least one helical elongate element comprises causing the two elongate elements to form two helical elongate elements.
7. The method according to claim 1 , wherein causing the at least one elongate element to form the at least one helical elongate element comprises causing the at least one elongate element to form at least one helical elongate element, the at least one helical elongate element defining less than half a winding of a helix.
8. The method according to claim 1 , wherein cutting the tube comprises cutting the tube such that the cut tube defines a structure having first and second rings at proximal and distal ends of the structure, and such that first and second ends of each of the at least one elongate element are disposed at an angle from one another with respect to circumferences of the rings, the angle being greater than 50 degrees.
9. The method according to claim 1 , wherein cutting the tube comprises cutting the tube such that the cut tube defines a structure having first and second rings at proximal and distal ends of the structure, and such that first and second ends of the at least one elongate element are disposed at an angle from one another with respect to circumferences of the rings, the angle being less than 180 degrees.
10. The method according to claim 1 , wherein coupling the material to the at least one helical elongate element comprises dipping at least a portion of the structure into the material while the material is in a liquid state, and drying the material, while the material is being supported by the at least one helical elongate element.
11. The method according to claim 10 , wherein tying sutures around the at least one elongate element comprises enhancing bonding between the at least one helical elongate element and the material by increasing a surface area with which the material comes into contact.
12. The method according to claim 10 , wherein tying sutures around the at least one elongate element comprises enhancing bonding between the at least one helical elongate element and the material by providing a surface that is more porous that that of the helical elongate element, with which the material comes into contact.
13. The method according to claim 10 , wherein the material includes silicone, and wherein drying the material comprises curing the silicone.