The third registry, NACI, was designed to gather information on the use of three types of intervention technologies other than PTCA. The interventional techniques were loosely grouped into several categories such as atherectomy, stents, and laster methods. Patients were contacted by telephone at six weeks, six months, and a year. The centers performed a treadmill test and a repeat angiogram at six months. To be investigated, a technique must have been used at two or more centers and a center must have used the intervention in at least five patients. Following acceptance into the registry for a technique, the clinical site admitted alll subsequent patients consecutively. Results were analyzed in batches of fifty, examining both patients and lesions as analytic units. The primary endpoint was reduction of a target lesion by at least 20 percent and to less than 50 percent final diameter stenosis without major complications. Secondary endpoints common to all devices included major events and additional events, health status at follow-up, and patency status at six months. In addition, there were secondary endpoints specific to the device under study. In 1993, an independent Angiographic Core Laboratory was established for the NACI under R01HL49527.