A pump for inducing motion of a fluid, the pump including a cannula adjustable between an operable configuration having a first diameter and a deployment configuration having a substantially smaller second diameter. An impeller is rotatable within the cannula about an axis. The impeller includes an at least semi-rigid support for a flexible web, and is positionable with respect to the cannula the operable configuration and the deployment configuration, the operable configuration extending the web to a first radial distance from the axis and the deployment configuration collapsing the web to a second substantially smaller radial distance from the axis.