US Patent 8684904 Blood pump with expandable cannula

A blood pump includes an impeller having a plurality of foldable blades and a cannula having a proximal portion with a fixed diameter, and a distal portion with an expandable diameter. The impeller can reside in the expandable portion of the cannula. The cannula has a collapsed condition for percutaneous delivery to a desired location within the body, and an expanded condition in which the impeller can rotate to pump blood. A flexible drive shaft can extend through the cannula for rotationally driving the impeller within the patient's body.