The catheter-based interventional treatment of branching points in blocked heart blood vessels is complex and prone to higher rate of complications. This study is intended to better understand why and under what conditions coronary blockages move during balloon angioplasty and stenting. The movement of coronary artery blockages during the standard treatment of coronary disease often leads to blocking of small artery branches near the treatment site. The blocking of these small branches does not occur at all times, but when it does occur it often results in small myocardial infarctions or residual chest pain.