Rotational atherectomy (Rotablation) is used in cases of calcium deposition in the coronary arteries, resulting in difficulty opening a stenosis with a balloon and stent. It consists of a burr, which at its front end contains microscopic diamond crystals. The burr rotates at approximately 150,000 revolutions per minute and, passing through the calcified atheromatous plaque, pulverizes the calcium into very small fragments that are absorbed by the circulation. Rotational atherectomy is usually followed by safe balloon inflation and stent placement.