Angioplasty of occluded coronary arteries: use of thin shaft balloon over-the-wire system without pre-dilatation. A retrospective review was done on 13 consecutive patients who underwent PTCA of totally occluded coronary arteries using a recently released thin shaft balloon over-the-wire angioplasty system. Balloon size was determined by the closest fit to the arterial size and used without predilatation techniques. This technique was initially successful in 12 patients with only 2 clinically insignificant episodes of distal embolization and one probable early reclosure. Using thin shaft angioplasty systems, balloon dilatation of totally occluded coronary arteries can be done safely with a single balloon in many cases resulting in simplified procedures and economic benefits. 