A vascular system comprises a balloon catheter (200, 210, 220, 230) and a vascular device (10, 100, 300). The balloon catheter has an elongated shaft (209) and an expandable balloon (240, 250, 250). The vascular device (10, 100, 300) is mounted over the expandable balloon and is composed of shape memory material. The vascular device has a collapsed position and a memorized position and is expandable to an expanded position to engage the vessel walls and returnable substantially to the memorized position to bring the walls radially inwardly.
