The first catheter is exchanged out over the guidewire for a guiding catheter and the guidewire is removed. A smaller guidewire is advanced across the blocked section of the coronary artery and a balloon -tipped tube is positioned so the balloon part of the tube is beside the blockage. The balloon is then inflated for a few seconds to compress the blockage against the artery wall. Then the balloon is deflated. The doctor may repeat this a few times, each time pumping up the balloon a little more to widen the passage for the blood to flow through. This treatment may be repeated at each blocked site in the coronary arteries.