Angioplasty is a procedure which opens blocked heart arteries using balloons and/or stents. Most U.S. states and all national heart organizations require that angioplasty be done only at hospitals that can also perform open heart surgery. The reason for this is that there is a risk that angioplasty can cause injury to the heart artery that might require open heart surgery to fix. Open heart surgery is a backup in case it is needed. The risk that open heart surgery will be needed is very small. Nevertheless, without more research, many state Departments of Health and all national heart organizations do not want to change the requirement for having on-site open heart surgery wherever angioplasty is performed. Some States already allow this; and European heart organizations already allow it, as well.