Heart assist device with expandable impeller pump

A method of manipulating an expandable pump, the pump comprising an expandable impeller and a cannula having an expandable portion comprising a mesh extending between a proximal portion of the cannula and a distal portion of the cannula and at least about the impeller, the cannula comprising an enclosure disposed about the mesh, the mesh comprising a first plurality of circumferential rings, each circumferential ring of the first plurality of circumferential rings comprising a plurality of distal crests, a plurality of proximal troughs, and a plurality of side segments extending between respective crests and troughs, wherein a first connector connects a first side segment of a first circumferential ring to a second circumferential ring, wherein each circumferential ring of the first plurality of circumferential rings is connected to an adjacent circumferential ring of the first plurality of circumferential rings by at least one connector, the pump further comprising a retainer sleeve disposed over the cannula, the cannula having an inlet and an outlet spaced from the inlet along an axial direction of the pump, the enclosure defining a space for the flow of blood in the axial direction, the method comprising:

• moving the retainer sleeve over the expandable portion of the cannula to compress the expandable portion of the cannula into a compressed state;
• such that the compressing of the expandable portion of the cannula causes the impeller to be compressed within the cannula to be in a stored configuration,
• the stored configuration being reversible to a deployed configuration by opposite relative motion.

A method of pumping blood within a subject, the method comprising:

• inserting a blood pump into the subject;
• positioning the blood pump so that an impeller and a cannula of the blood pump are at a desired location, the cannula having a mesh with circumferential rings that are at least partially interleaved, the cannula having an inlet and an outlet spaced from the inlet along an axial direction of the blood pump and an enclosure disposed about the mesh, the enclosure defining a space for the flow of blood in the axial direction, wherein each circumferential ring comprises a plurality of distal crests, a plurality of proximal troughs, and a plurality of side segments extending between respective crests and troughs, and wherein the crests of a first circumferential ring are distal of the troughs of a second circumferential ring, the second circumferential ring distal the first circumferential ring;
• expanding the cannula and the impeller within the cannula at the desired location;
• and
• pumping blood through the cannula along the axial direction.

A method of pumping blood within a subject, the method comprising:

• inserting a blood pump into the subject;
• positioning the blood pump so that an impeller and a cannula of the blood pump are at a desired location, the cannula having a mesh with a first plurality of circumferential rings, each circumferential ring of the first plurality of circumferential rings comprising a plurality of distal crests, a plurality of proximal troughs, and a plurality of side segments extending between respective crests and troughs, wherein a first connector connects a first side segment of a first circumferential ring to a second circumferential ring, wherein each circumferential ring of the first plurality of circumferential rings is connected to an adjacent circumferential ring of the first plurality of circumferential rings by at least one connector;
• and
• expanding the cannula and the impeller within the cannula at the desired location.

A blood pump comprising:

• a cannula having a mesh with a plurality of circumferential rings that are at least partially interleaved, the cannula having an inlet, an outlet spaced from the inlet along an axial direction of the blood pump, and an enclosure disposed about the mesh, the enclosure defining a space for the flow of blood in the axial direction;
• and
• an impeller disposed in the cannula,
• wherein each circumferential ring comprises a plurality of distal crests, a plurality of proximal troughs, and a plurality of side segments extending between respective crests and troughs, and
• wherein the crests of a first circumferential ring are at least partially nested within the crests of a second circumferential ring that is adjacent to the first circumferential ring.