A circulatory assist apparatus comprising: an inflatable pumping balloon having a proximal end joined to an elongated balloon catheter, the balloon catheter having a distal end joined to the pumping balloon and a proximal end, separated from the distal end by a length sufficient to extend from within a circulatory lumen to the outside of a patient's body, for receiving positive and negative pressure pulses from a pump to inflate and deflate the pumping balloon； and a radially expandable frame, mounted on one of a segment extending distally from the pumping balloon, the balloon catheter, and a sleeve tube surrounding the balloon catheter. The expandable frame is manipulable to expand within the circulatory lumen, and functions to space apart the inflatable balloon from the circulatory lumen, having a first diameter in a collapsed configuration for intraluminal delivery and a second, larger diameter in an expanded configuration achieved by said manipulation.
