Angioplasty or PTCA as it is popularly known, is aimed at removing the blockages of the coronary arteries to restore the blood flow. Stenting is now used in about 60% of angioplasty procedures. Studies report high survival rates with the use of stents, including their use with multiple blood vessels and as the initial device after a heart attack instead of balloon angioplasty. Recently, however, this widespread use is being questioned. In one study, there was no difference in outcome between balloon angioplasty and coronary stents, except in certain cases. Of additional concern was a 1999 study reporting more injury to the walls of the artery after six months in patients with coronary stents compared to angioplasty or atherectomy. Research is needed to determine which individuals would benefit most from stents. Some experts now recommend they be used only to prevent restenosis in patients with large blood vessels (greater than 3 mm).