Prevalence of anomalous origin of coronary arteries: a retrospective study in a Portuguese population.

The definition, prevalence, classification and clinical relevance of anomalous origin of coronary arteries (AOCA) are still the subject of debate. Most international series estimate its prevalence at 1-2% but we found values ranging from 0.3 to 5.6% in the literature. The prevalence in our population was 0.54%, absence of the left main coronary artery being the most common anomaly (0.38%.). There were two cases involving the circumflex artery, one the anterior descending artery, two of the left main artery originating from the right coronary sinus, and one of the right coronary artery originating from the left coronary sinus. The aim of this retrospective study was to assess the prevalence of AOCA in an unselected population undergoing coronary angiography and to characterize that population.