Abstract: An intra-aortic balloon (IAB) having an elongated member expandable within said balloon to prevent total collapse of the balloon or any portion thereof during deflation. The member preventing balloon collapse, in one preferred embodiment, is stored in the catheter tube in the collapsed state and expands when moved into the balloon. In another embodiment, the member preventing deflation is arranged within the balloon and is provided with an operating member for selectively expanding and collapsing the member provided for preventing deflation. Moving the member for preventing deflation to the collapsed state permits the profile of the balloon to be significantly reduced which aids in percutaneous insertion and in removal of the balloon.