The New Approaches to Coronary Intervention (NACI) registry was funded in 1990 by the National Heart, Lung, and Blood Institute to evaluate the safety and efficacy of new coronary interventional devices. The registry collected data from 39 clinical centers on 8 new devices: 3 atherectomy devices, 2 stents, 2 laser devices and the laser balloon. The original funding called for a total of 500 patients to be recruited for each device. One device (the laser balloon) was removed from use early in the recruitment period. Subsequent funding was obtained for an additional 500 patients treated with directional atherectomy, and 500 additional female patients who were recruited when the main recruitment had finished. When all recruitment was finished in March 1994, a total of 4,429 patients had been recruited. Consecutive patients treated with a new device at each clinical site were recruited regardless of underlying clinical condition or result. Patients were followed for 1 year by telephone contact at 6 weeks, 6 months and 1 year. Overall 1-year follow-up compliance was excellent at 96% of patients. The NACI database was designed to allow analysis of the complex relationships between patient, lesion and device. In particular, the mode of use of each device, the treatment order, and the outcome after each device attempt were recorded. All in-hospital clinical events were recorded as well as an assessment of the success of the procedure by the operator. The results of each telephone follow-up included any interim cardiac events, anginal status, and results of any subsequent angiograms or exercise test. Any repeat percutaneous procedures or bypass surgery on an NACI patient were recorded in the same detail as the original procedure. All data collected were subjected to extensive editing at the coordinating center to ensure both internal and external consistency. An angiographic core laboratory was also funded for NACI in 1992 to provide uniform analyses of procedural angiograms. Measurements were made at each step of the procedure, that is preprocedure, after each device use, and postprocedure. Both quantitative and qualitative measurements were made at each step using standardized definitions, enabling a complete description of the procedure to be analyzed. Angiograms were made available to the core laboratory for 89% of all initial procedures.