The PTCA III or NACI Registry was established in 1990 to follow revascularization devices or methods other than PTCA. Utilization of PTCA experienced an explosive growth since it was first introduced. However, despite this rapid growth in technological improvements and techniques, balloon angioplasty is not universally successful. Problems relate to failure to cross chronic total occlusions, failure to successfully dilate elastic lesions, intimal dissection and abrupt closure which leads to emergency surgery, and most particularly, restenosis of the dilated segment. In the late 1970s, diverse technologies were developed in an attempt to counter the problems plaguing coronary angioplasty. These technologies include: mechanical devices for crossing total occlusions; atherectomy catheters; abrasive athero-dispersion devices; intracoronary stents; ablative lasers; hot-tip lasers, and laser balloon dilation techniques. Each of the above device categories entered clinical testing. However, these devices were in a state of flux. Moreover, these devices were utilized in different clinical settings, with different definitions of success and complication rates and different follow-up regimens. Therefore, it was difficult to judge the relative efficacy of any single device in comparison to standard PTCA. The need to establish a mechanism capable of evaluating each device was, therefore, of practical importance from a clinical and investigational standpoint. The primary purpose of the registry was not to compare devices but to follow simultaneously the progress of multiple devices in a parallel fashion, using common methodologies and definitions in their early clinical usage.