CATHETER BLOOD PUMPS AND METHODS OF USE AND MANUFACTURE
Catheter blood pumps and methods of use and manufacture. The pumps may include an expandable and collapsible shroud that defines a blood lumen. The shroud may include a polymeric scaffold along at least a portion of a length of the shroud. The pumps may include one or more impellers.
1 - 48 . (canceled)
49 . A blood pump, comprising:
an expandable and collapsible shroud that defines a blood lumen, the shroud comprising a proximal impeller region and a central region positioned distally to the proximal impeller region, wherein the proximal impeller region has a first stiffness that is greater than a second stiffness of the central region;
a proximal impeller disposed at least partially within the proximal impeller region of the shroud.
50 . The blood pump of claim 49 , wherein the expandable and collapsible shroud includes a plurality of helical arms to define at least one helical region.
51 . The blood pump of claim 50 , wherein at least one helical region axially overlaps with the proximal impeller.
52 . The blood pump of claim 50 , wherein a plurality of helical regions axially overlaps with the proximal impeller.
53 . The blood pump of claim 50 , wherein at least one of the plurality of helical arms extends between adjacent non-helical regions.
54 . The blood pump of claim 50 , wherein at least one helical region extends between adjacent non-helical regions of the expandable and collapsible shroud.
55 . The blood pump of claim 49 , wherein the proximal impeller region of the expandable and collapsible shroud includes a plurality of helical arms to define at least one helical region.
56 . The blood pump of claim 55 , wherein at least one helical region axially overlaps with the proximal impeller.
57 . The blood pump of claim 55 , wherein a plurality of helical regions axially overlaps with the proximal impeller.
58 . The blood pump of claim 55 , wherein at least one of the plurality of helical arms extends between adjacent non-helical regions.
59 . The blood pump of claim 50 , wherein the proximal impeller region comprises at least one helical region and the central region comprises at least one non-helical region.
60 . The blood pump of claim 49 , further comprising a membrane coupled to the expandable and collapsible shroud to define a fluid conduit that is impermeable to blood.
61 . The blood pump of claim 49 , wherein the expandable and collapsible shroud comprises nitinol.
62 . The blood pump of claim 49 , wherein the expandable and collapsible shroud comprises a polymeric structure.
63 . The blood pump of claim 62 , wherein a first durometer of the proximal impeller region is greater than a second durometer of the central region.
64 . The blood pump of claim 49 , wherein the expandable and collapsible shroud comprises a distal impeller region positioned distally to the central region, wherein the distal impeller region has a third stiffness that is greater than the second stiffness of the central region, the blood pump further comprising a distal impeller disposed at least partially within the distal impeller region of the shroud.
65 . The blood pump of claim 64 , wherein the first stiffness of the proximal impeller region is substantially similar to the third stiffness of the distal impeller region.
66 . The blood pump of claim 49 , wherein the proximal impeller region is configured to maintain a tip gap between the proximal impeller and the expandable and collapsible shroud ranging from 0.01 mm to 1 mm.
67 . The blood pump of claim 49 , wherein the proximal impeller region is configured to maintain a tip gap between the proximal impeller and the expandable and collapsible shroud ranging from 0.5 mm to 1 mm.
68 . The blood pump of claim 49 , wherein the greater stiffness of the proximal impeller region is configured to maintain concentricity between the proximal impeller and the expandable and collapsible shroud.