BACKGROUND: Due to its pivotal role in the management of patients with ischemic heart disease, the use of coronary angiography has been continuously and progressively increasing over the years. However, an inappropriate rate of its utilization has been reported in 2 to 58% of cases. The aim of our study was therefore to evaluate the appropriateness of the indications for coronary angiography at our Institution. METHODS: All the patients undergoing coronary angiography at the catheterization laboratory of the Maggiore Hospital in Bologna during 1999 were evaluated. By retrospectively reviewing the data forms filled in at the time of insertion of the patient on the waiting list, the indications for coronary angiography were categorized as appropriate (class I/IIa), of uncertain value (class IIb) and inappropriate (class III), according to the guidelines of the American College of Cardiology/American Heart Association. In a blind fashion to this classification, the reports of coronary angiography were also reviewed to determine, both globally and in the different clinical subsets, the prevalence of significant coronary stenoses and of angiographically normal vessels. RESULTS: Class I/IIa indications were found in 72% of patients, as opposed to 28% in class lIb and none in class III. In the clinical subsets of stable angina, previous myocardial infarction and out-of-hospital cardiac arrest, the appropriateness was significantly higher, ranging from 74 to 100%, compared to recent myocardial infarction (63%) and unstable angina (59%) (accounting by itself for about one half of all class IIb indications). The overall prevalence of significant coronary artery disease was 87%, while in only 3% of cases did coronary angiography reveal normal vessels. CONCLUSIONS: In our population, the use of coronary angiography was highly appropriate and only seldom of uncertain value. The accurate noninvasive selection of patients which, in view of the limited access to the catheterization laboratory, we needed to perform before proceeding to coronary angiography probably played a major role in these results.